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TOMOYO Linux Cross Reference
Linux/arch/Kconfig

Version: ~ [ linux-6.11.5 ] ~ [ linux-6.10.14 ] ~ [ linux-6.9.12 ] ~ [ linux-6.8.12 ] ~ [ linux-6.7.12 ] ~ [ linux-6.6.58 ] ~ [ linux-6.5.13 ] ~ [ linux-6.4.16 ] ~ [ linux-6.3.13 ] ~ [ linux-6.2.16 ] ~ [ linux-6.1.114 ] ~ [ linux-6.0.19 ] ~ [ linux-5.19.17 ] ~ [ linux-5.18.19 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.169 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.228 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.284 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.322 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.336 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.337 ] ~ [ linux-4.4.302 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.9 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

Diff markup

Differences between /arch/Kconfig (Version linux-6.11.5) and /arch/Kconfig (Version linux-5.16.20)


  1 # SPDX-License-Identifier: GPL-2.0                  1 # SPDX-License-Identifier: GPL-2.0
  2 #                                                   2 #
  3 # General architecture dependent options            3 # General architecture dependent options
  4 #                                                   4 #
  5                                                     5 
  6 #                                                   6 #
  7 # Note: arch/$(SRCARCH)/Kconfig needs to be in      7 # Note: arch/$(SRCARCH)/Kconfig needs to be included first so that it can
  8 # override the default values in this file.         8 # override the default values in this file.
  9 #                                                   9 #
 10 source "arch/$(SRCARCH)/Kconfig"                   10 source "arch/$(SRCARCH)/Kconfig"
 11                                                    11 
 12 config ARCH_CONFIGURES_CPU_MITIGATIONS         << 
 13         bool                                   << 
 14                                                << 
 15 if !ARCH_CONFIGURES_CPU_MITIGATIONS            << 
 16 config CPU_MITIGATIONS                         << 
 17         def_bool y                             << 
 18 endif                                          << 
 19                                                << 
 20 menu "General architecture-dependent options"      12 menu "General architecture-dependent options"
 21                                                    13 
 22 config ARCH_HAS_SUBPAGE_FAULTS                 !!  14 config CRASH_CORE
 23         bool                                   << 
 24         help                                   << 
 25           Select if the architecture can check << 
 26           granularity (e.g. arm64 MTE). The pr << 
 27           must be implemented.                 << 
 28                                                << 
 29 config HOTPLUG_SMT                             << 
 30         bool                                   << 
 31                                                << 
 32 config SMT_NUM_THREADS_DYNAMIC                 << 
 33         bool                                       15         bool
 34                                                    16 
 35 # Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLU !!  17 config KEXEC_CORE
 36 config HOTPLUG_CORE_SYNC                       !!  18         select CRASH_CORE
 37         bool                                       19         bool
 38                                                    20 
 39 # Basic CPU dead synchronization selected by a !!  21 config KEXEC_ELF
 40 config HOTPLUG_CORE_SYNC_DEAD                  << 
 41         bool                                       22         bool
 42         select HOTPLUG_CORE_SYNC               << 
 43                                                    23 
 44 # Full CPU synchronization with alive state se !!  24 config HAVE_IMA_KEXEC
 45 config HOTPLUG_CORE_SYNC_FULL                  << 
 46         bool                                       25         bool
 47         select HOTPLUG_CORE_SYNC_DEAD if HOTPL << 
 48         select HOTPLUG_CORE_SYNC               << 
 49                                                    26 
 50 config HOTPLUG_SPLIT_STARTUP                   !!  27 config SET_FS
 51         bool                                       28         bool
 52         select HOTPLUG_CORE_SYNC_FULL          << 
 53                                                    29 
 54 config HOTPLUG_PARALLEL                        !!  30 config HOTPLUG_SMT
 55         bool                                       31         bool
 56         select HOTPLUG_SPLIT_STARTUP           << 
 57                                                    32 
 58 config GENERIC_ENTRY                               33 config GENERIC_ENTRY
 59         bool                                   !!  34        bool
 60                                                    35 
 61 config KPROBES                                     36 config KPROBES
 62         bool "Kprobes"                             37         bool "Kprobes"
                                                   >>  38         depends on MODULES
 63         depends on HAVE_KPROBES                    39         depends on HAVE_KPROBES
 64         select KALLSYMS                            40         select KALLSYMS
 65         select EXECMEM                         << 
 66         select NEED_TASKS_RCU                  << 
 67         help                                       41         help
 68           Kprobes allows you to trap at almost     42           Kprobes allows you to trap at almost any kernel address and
 69           execute a callback function.  regist     43           execute a callback function.  register_kprobe() establishes
 70           a probepoint and specifies the callb     44           a probepoint and specifies the callback.  Kprobes is useful
 71           for kernel debugging, non-intrusive      45           for kernel debugging, non-intrusive instrumentation and testing.
 72           If in doubt, say "N".                    46           If in doubt, say "N".
 73                                                    47 
 74 config JUMP_LABEL                                  48 config JUMP_LABEL
 75         bool "Optimize very unlikely/likely br     49         bool "Optimize very unlikely/likely branches"
 76         depends on HAVE_ARCH_JUMP_LABEL            50         depends on HAVE_ARCH_JUMP_LABEL
 77         select OBJTOOL if HAVE_JUMP_LABEL_HACK !!  51         depends on CC_HAS_ASM_GOTO
 78         help                                       52         help
 79           This option enables a transparent br !!  53          This option enables a transparent branch optimization that
 80           makes certain almost-always-true or  !!  54          makes certain almost-always-true or almost-always-false branch
 81           conditions even cheaper to execute w !!  55          conditions even cheaper to execute within the kernel.
 82                                                !!  56 
 83           Certain performance-sensitive kernel !!  57          Certain performance-sensitive kernel code, such as trace points,
 84           scheduler functionality, networking  !!  58          scheduler functionality, networking code and KVM have such
 85           branches and include support for thi !!  59          branches and include support for this optimization technique.
 86                                                !!  60 
 87           If it is detected that the compiler  !!  61          If it is detected that the compiler has support for "asm goto",
 88           the kernel will compile such branche !!  62          the kernel will compile such branches with just a nop
 89           instruction. When the condition flag !!  63          instruction. When the condition flag is toggled to true, the
 90           nop will be converted to a jump inst !!  64          nop will be converted to a jump instruction to execute the
 91           conditional block of instructions.   !!  65          conditional block of instructions.
 92                                                !!  66 
 93           This technique lowers overhead and s !!  67          This technique lowers overhead and stress on the branch prediction
 94           of the processor and generally makes !!  68          of the processor and generally makes the kernel faster. The update
 95           of the condition is slower, but thos !!  69          of the condition is slower, but those are always very rare.
 96                                                    70 
 97           ( On 32-bit x86, the necessary optio !!  71          ( On 32-bit x86, the necessary options added to the compiler
 98             flags may increase the size of the !!  72            flags may increase the size of the kernel slightly. )
 99                                                    73 
100 config STATIC_KEYS_SELFTEST                        74 config STATIC_KEYS_SELFTEST
101         bool "Static key selftest"                 75         bool "Static key selftest"
102         depends on JUMP_LABEL                      76         depends on JUMP_LABEL
103         help                                       77         help
104           Boot time self-test of the branch pa     78           Boot time self-test of the branch patching code.
105                                                    79 
106 config STATIC_CALL_SELFTEST                        80 config STATIC_CALL_SELFTEST
107         bool "Static call selftest"                81         bool "Static call selftest"
108         depends on HAVE_STATIC_CALL                82         depends on HAVE_STATIC_CALL
109         help                                       83         help
110           Boot time self-test of the call patc     84           Boot time self-test of the call patching code.
111                                                    85 
112 config OPTPROBES                                   86 config OPTPROBES
113         def_bool y                                 87         def_bool y
114         depends on KPROBES && HAVE_OPTPROBES       88         depends on KPROBES && HAVE_OPTPROBES
115         select NEED_TASKS_RCU                  !!  89         select TASKS_RCU if PREEMPTION
116                                                    90 
117 config KPROBES_ON_FTRACE                           91 config KPROBES_ON_FTRACE
118         def_bool y                                 92         def_bool y
119         depends on KPROBES && HAVE_KPROBES_ON_     93         depends on KPROBES && HAVE_KPROBES_ON_FTRACE
120         depends on DYNAMIC_FTRACE_WITH_REGS        94         depends on DYNAMIC_FTRACE_WITH_REGS
121         help                                       95         help
122           If function tracer is enabled and th !!  96          If function tracer is enabled and the arch supports full
123           passing of pt_regs to function traci !!  97          passing of pt_regs to function tracing, then kprobes can
124           optimize on top of function tracing. !!  98          optimize on top of function tracing.
125                                                    99 
126 config UPROBES                                    100 config UPROBES
127         def_bool n                                101         def_bool n
128         depends on ARCH_SUPPORTS_UPROBES          102         depends on ARCH_SUPPORTS_UPROBES
129         help                                      103         help
130           Uprobes is the user-space counterpar    104           Uprobes is the user-space counterpart to kprobes: they
131           enable instrumentation applications     105           enable instrumentation applications (such as 'perf probe')
132           to establish unintrusive probes in u    106           to establish unintrusive probes in user-space binaries and
133           libraries, by executing handler func    107           libraries, by executing handler functions when the probes
134           are hit by user-space applications.     108           are hit by user-space applications.
135                                                   109 
136           ( These probes come in the form of s    110           ( These probes come in the form of single-byte breakpoints,
137             managed by the kernel and kept tra    111             managed by the kernel and kept transparent to the probed
138             application. )                        112             application. )
139                                                   113 
140 config HAVE_64BIT_ALIGNED_ACCESS                  114 config HAVE_64BIT_ALIGNED_ACCESS
141         def_bool 64BIT && !HAVE_EFFICIENT_UNAL    115         def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
142         help                                      116         help
143           Some architectures require 64 bit ac    117           Some architectures require 64 bit accesses to be 64 bit
144           aligned, which also requires structs    118           aligned, which also requires structs containing 64 bit values
145           to be 64 bit aligned too. This inclu    119           to be 64 bit aligned too. This includes some 32 bit
146           architectures which can do 64 bit ac    120           architectures which can do 64 bit accesses, as well as 64 bit
147           architectures without unaligned acce    121           architectures without unaligned access.
148                                                   122 
149           This symbol should be selected by an    123           This symbol should be selected by an architecture if 64 bit
150           accesses are required to be 64 bit a    124           accesses are required to be 64 bit aligned in this way even
151           though it is not a 64 bit architectu    125           though it is not a 64 bit architecture.
152                                                   126 
153           See Documentation/core-api/unaligned    127           See Documentation/core-api/unaligned-memory-access.rst for
154           more information on the topic of una    128           more information on the topic of unaligned memory accesses.
155                                                   129 
156 config HAVE_EFFICIENT_UNALIGNED_ACCESS            130 config HAVE_EFFICIENT_UNALIGNED_ACCESS
157         bool                                      131         bool
158         help                                      132         help
159           Some architectures are unable to per    133           Some architectures are unable to perform unaligned accesses
160           without the use of get_unaligned/put    134           without the use of get_unaligned/put_unaligned. Others are
161           unable to perform such accesses effi    135           unable to perform such accesses efficiently (e.g. trap on
162           unaligned access and require fixing     136           unaligned access and require fixing it up in the exception
163           handler.)                               137           handler.)
164                                                   138 
165           This symbol should be selected by an    139           This symbol should be selected by an architecture if it can
166           perform unaligned accesses efficient    140           perform unaligned accesses efficiently to allow different
167           code paths to be selected for these     141           code paths to be selected for these cases. Some network
168           drivers, for example, could opt to n    142           drivers, for example, could opt to not fix up alignment
169           problems with received packets if do    143           problems with received packets if doing so would not help
170           much.                                   144           much.
171                                                   145 
172           See Documentation/core-api/unaligned    146           See Documentation/core-api/unaligned-memory-access.rst for more
173           information on the topic of unaligne    147           information on the topic of unaligned memory accesses.
174                                                   148 
175 config ARCH_USE_BUILTIN_BSWAP                     149 config ARCH_USE_BUILTIN_BSWAP
176         bool                                      150         bool
177         help                                      151         help
178           Modern versions of GCC (since 4.4) h !! 152          Modern versions of GCC (since 4.4) have builtin functions
179           for handling byte-swapping. Using th !! 153          for handling byte-swapping. Using these, instead of the old
180           inline assembler that the architectu !! 154          inline assembler that the architecture code provides in the
181           __arch_bswapXX() macros, allows the  !! 155          __arch_bswapXX() macros, allows the compiler to see what's
182           happening and offers more opportunit !! 156          happening and offers more opportunity for optimisation. In
183           particular, the compiler will be abl !! 157          particular, the compiler will be able to combine the byteswap
184           with a nearby load or store and use  !! 158          with a nearby load or store and use load-and-swap or
185           store-and-swap instructions if the a !! 159          store-and-swap instructions if the architecture has them. It
186           should almost *never* result in code !! 160          should almost *never* result in code which is worse than the
187           hand-coded assembler in <asm/swab.h> !! 161          hand-coded assembler in <asm/swab.h>.  But just in case it
188           does, the use of the builtins is opt !! 162          does, the use of the builtins is optional.
189                                                !! 163 
190           Any architecture with load-and-swap  !! 164          Any architecture with load-and-swap or store-and-swap
191           instructions should set this. And it !! 165          instructions should set this. And it shouldn't hurt to set it
192           on architectures that don't have suc !! 166          on architectures that don't have such instructions.
193                                                   167 
194 config KRETPROBES                                 168 config KRETPROBES
195         def_bool y                                169         def_bool y
196         depends on KPROBES && (HAVE_KRETPROBES !! 170         depends on KPROBES && HAVE_KRETPROBES
197                                                << 
198 config KRETPROBE_ON_RETHOOK                    << 
199         def_bool y                             << 
200         depends on HAVE_RETHOOK                << 
201         depends on KRETPROBES                  << 
202         select RETHOOK                         << 
203                                                   171 
204 config USER_RETURN_NOTIFIER                       172 config USER_RETURN_NOTIFIER
205         bool                                      173         bool
206         depends on HAVE_USER_RETURN_NOTIFIER      174         depends on HAVE_USER_RETURN_NOTIFIER
207         help                                      175         help
208           Provide a kernel-internal notificati    176           Provide a kernel-internal notification when a cpu is about to
209           switch to user mode.                    177           switch to user mode.
210                                                   178 
211 config HAVE_IOREMAP_PROT                          179 config HAVE_IOREMAP_PROT
212         bool                                      180         bool
213                                                   181 
214 config HAVE_KPROBES                               182 config HAVE_KPROBES
215         bool                                      183         bool
216                                                   184 
217 config HAVE_KRETPROBES                            185 config HAVE_KRETPROBES
218         bool                                      186         bool
219                                                   187 
220 config HAVE_OPTPROBES                             188 config HAVE_OPTPROBES
221         bool                                      189         bool
222                                                   190 
223 config HAVE_KPROBES_ON_FTRACE                     191 config HAVE_KPROBES_ON_FTRACE
224         bool                                      192         bool
225                                                   193 
226 config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE       194 config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
227         bool                                      195         bool
228         help                                      196         help
229           Since kretprobes modifies return add    197           Since kretprobes modifies return address on the stack, the
230           stacktrace may see the kretprobe tra    198           stacktrace may see the kretprobe trampoline address instead
231           of correct one. If the architecture     199           of correct one. If the architecture stacktrace code and
232           unwinder can adjust such entries, se    200           unwinder can adjust such entries, select this configuration.
233                                                   201 
234 config HAVE_FUNCTION_ERROR_INJECTION              202 config HAVE_FUNCTION_ERROR_INJECTION
235         bool                                      203         bool
236                                                   204 
237 config HAVE_NMI                                   205 config HAVE_NMI
238         bool                                      206         bool
239                                                   207 
240 config HAVE_FUNCTION_DESCRIPTORS               << 
241         bool                                   << 
242                                                << 
243 config TRACE_IRQFLAGS_SUPPORT                     208 config TRACE_IRQFLAGS_SUPPORT
244         bool                                      209         bool
245                                                   210 
246 config TRACE_IRQFLAGS_NMI_SUPPORT              << 
247         bool                                   << 
248                                                << 
249 #                                                 211 #
250 # An arch should select this if it provides al    212 # An arch should select this if it provides all these things:
251 #                                                 213 #
252 #       task_pt_regs()          in asm/process    214 #       task_pt_regs()          in asm/processor.h or asm/ptrace.h
253 #       arch_has_single_step()  if there is ha    215 #       arch_has_single_step()  if there is hardware single-step support
254 #       arch_has_block_step()   if there is ha    216 #       arch_has_block_step()   if there is hardware block-step support
255 #       asm/syscall.h           supplying asm-    217 #       asm/syscall.h           supplying asm-generic/syscall.h interface
256 #       linux/regset.h          user_regset in    218 #       linux/regset.h          user_regset interfaces
257 #       CORE_DUMP_USE_REGSET    #define'd in l    219 #       CORE_DUMP_USE_REGSET    #define'd in linux/elf.h
258 #       TIF_SYSCALL_TRACE       calls ptrace_r !! 220 #       TIF_SYSCALL_TRACE       calls tracehook_report_syscall_{entry,exit}
259 #       TIF_NOTIFY_RESUME       calls resume_u !! 221 #       TIF_NOTIFY_RESUME       calls tracehook_notify_resume()
                                                   >> 222 #       signal delivery         calls tracehook_signal_handler()
260 #                                                 223 #
261 config HAVE_ARCH_TRACEHOOK                        224 config HAVE_ARCH_TRACEHOOK
262         bool                                      225         bool
263                                                   226 
264 config HAVE_DMA_CONTIGUOUS                        227 config HAVE_DMA_CONTIGUOUS
265         bool                                      228         bool
266                                                   229 
267 config GENERIC_SMP_IDLE_THREAD                    230 config GENERIC_SMP_IDLE_THREAD
268         bool                                      231         bool
269                                                   232 
270 config GENERIC_IDLE_POLL_SETUP                    233 config GENERIC_IDLE_POLL_SETUP
271         bool                                      234         bool
272                                                   235 
273 config ARCH_HAS_FORTIFY_SOURCE                    236 config ARCH_HAS_FORTIFY_SOURCE
274         bool                                      237         bool
275         help                                      238         help
276           An architecture should select this w    239           An architecture should select this when it can successfully
277           build and run with CONFIG_FORTIFY_SO    240           build and run with CONFIG_FORTIFY_SOURCE.
278                                                   241 
279 #                                                 242 #
280 # Select if the arch provides a historic keepi    243 # Select if the arch provides a historic keepinit alias for the retain_initrd
281 # command line option                             244 # command line option
282 #                                                 245 #
283 config ARCH_HAS_KEEPINITRD                        246 config ARCH_HAS_KEEPINITRD
284         bool                                      247         bool
285                                                   248 
286 # Select if arch has all set_memory_ro/rw/x/nx    249 # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
287 config ARCH_HAS_SET_MEMORY                        250 config ARCH_HAS_SET_MEMORY
288         bool                                      251         bool
289                                                   252 
290 # Select if arch has all set_direct_map_invali    253 # Select if arch has all set_direct_map_invalid/default() functions
291 config ARCH_HAS_SET_DIRECT_MAP                    254 config ARCH_HAS_SET_DIRECT_MAP
292         bool                                      255         bool
293                                                   256 
294 #                                                 257 #
295 # Select if the architecture provides the arch    258 # Select if the architecture provides the arch_dma_set_uncached symbol to
296 # either provide an uncached segment alias for    259 # either provide an uncached segment alias for a DMA allocation, or
297 # to remap the page tables in place.              260 # to remap the page tables in place.
298 #                                                 261 #
299 config ARCH_HAS_DMA_SET_UNCACHED                  262 config ARCH_HAS_DMA_SET_UNCACHED
300         bool                                      263         bool
301                                                   264 
302 #                                                 265 #
303 # Select if the architectures provides the arc    266 # Select if the architectures provides the arch_dma_clear_uncached symbol
304 # to undo an in-place page table remap for unc    267 # to undo an in-place page table remap for uncached access.
305 #                                                 268 #
306 config ARCH_HAS_DMA_CLEAR_UNCACHED                269 config ARCH_HAS_DMA_CLEAR_UNCACHED
307         bool                                      270         bool
308                                                   271 
309 config ARCH_HAS_CPU_FINALIZE_INIT              !! 272 # Select if arch init_task must go in the __init_task_data section
                                                   >> 273 config ARCH_TASK_STRUCT_ON_STACK
310         bool                                      274         bool
311                                                   275 
312 # The architecture has a per-task state that i !! 276 # Select if arch has its private alloc_task_struct() function
313 config ARCH_HAS_CPU_PASID                      !! 277 config ARCH_TASK_STRUCT_ALLOCATOR
314         bool                                      278         bool
315         select IOMMU_MM_DATA                   << 
316                                                   279 
317 config HAVE_ARCH_THREAD_STRUCT_WHITELIST          280 config HAVE_ARCH_THREAD_STRUCT_WHITELIST
318         bool                                      281         bool
                                                   >> 282         depends on !ARCH_TASK_STRUCT_ALLOCATOR
319         help                                      283         help
320           An architecture should select this t    284           An architecture should select this to provide hardened usercopy
321           knowledge about what region of the t    285           knowledge about what region of the thread_struct should be
322           whitelisted for copying to userspace    286           whitelisted for copying to userspace. Normally this is only the
323           FPU registers. Specifically, arch_th    287           FPU registers. Specifically, arch_thread_struct_whitelist()
324           should be implemented. Without this,    288           should be implemented. Without this, the entire thread_struct
325           field in task_struct will be left wh    289           field in task_struct will be left whitelisted.
326                                                   290 
                                                   >> 291 # Select if arch has its private alloc_thread_stack() function
                                                   >> 292 config ARCH_THREAD_STACK_ALLOCATOR
                                                   >> 293         bool
                                                   >> 294 
327 # Select if arch wants to size task_struct dyn    295 # Select if arch wants to size task_struct dynamically via arch_task_struct_size:
328 config ARCH_WANTS_DYNAMIC_TASK_STRUCT             296 config ARCH_WANTS_DYNAMIC_TASK_STRUCT
329         bool                                      297         bool
330                                                   298 
331 config ARCH_WANTS_NO_INSTR                        299 config ARCH_WANTS_NO_INSTR
332         bool                                      300         bool
333         help                                      301         help
334           An architecture should select this i    302           An architecture should select this if the noinstr macro is being used on
335           functions to denote that the toolcha    303           functions to denote that the toolchain should avoid instrumenting such
336           functions and is required for correc    304           functions and is required for correctness.
337                                                   305 
338 config ARCH_32BIT_OFF_T                           306 config ARCH_32BIT_OFF_T
339         bool                                      307         bool
340         depends on !64BIT                         308         depends on !64BIT
341         help                                      309         help
342           All new 32-bit architectures should     310           All new 32-bit architectures should have 64-bit off_t type on
343           userspace side which corresponds to     311           userspace side which corresponds to the loff_t kernel type. This
344           is the requirement for modern ABIs.     312           is the requirement for modern ABIs. Some existing architectures
345           still support 32-bit off_t. This opt    313           still support 32-bit off_t. This option is enabled for all such
346           architectures explicitly.               314           architectures explicitly.
347                                                   315 
348 # Selected by 64 bit architectures which have     316 # Selected by 64 bit architectures which have a 32 bit f_tinode in struct ustat
349 config ARCH_32BIT_USTAT_F_TINODE                  317 config ARCH_32BIT_USTAT_F_TINODE
350         bool                                      318         bool
351                                                   319 
352 config HAVE_ASM_MODVERSIONS                       320 config HAVE_ASM_MODVERSIONS
353         bool                                      321         bool
354         help                                      322         help
355           This symbol should be selected by an    323           This symbol should be selected by an architecture if it provides
356           <asm/asm-prototypes.h> to support th    324           <asm/asm-prototypes.h> to support the module versioning for symbols
357           exported from assembly code.            325           exported from assembly code.
358                                                   326 
359 config HAVE_REGS_AND_STACK_ACCESS_API             327 config HAVE_REGS_AND_STACK_ACCESS_API
360         bool                                      328         bool
361         help                                      329         help
362           This symbol should be selected by an    330           This symbol should be selected by an architecture if it supports
363           the API needed to access registers a    331           the API needed to access registers and stack entries from pt_regs,
364           declared in asm/ptrace.h                332           declared in asm/ptrace.h
365           For example the kprobes-based event     333           For example the kprobes-based event tracer needs this API.
366                                                   334 
367 config HAVE_RSEQ                                  335 config HAVE_RSEQ
368         bool                                      336         bool
369         depends on HAVE_REGS_AND_STACK_ACCESS_    337         depends on HAVE_REGS_AND_STACK_ACCESS_API
370         help                                      338         help
371           This symbol should be selected by an    339           This symbol should be selected by an architecture if it
372           supports an implementation of restar    340           supports an implementation of restartable sequences.
373                                                   341 
374 config HAVE_RUST                               << 
375         bool                                   << 
376         help                                   << 
377           This symbol should be selected by an << 
378           supports Rust.                       << 
379                                                << 
380 config HAVE_FUNCTION_ARG_ACCESS_API               342 config HAVE_FUNCTION_ARG_ACCESS_API
381         bool                                      343         bool
382         help                                      344         help
383           This symbol should be selected by an    345           This symbol should be selected by an architecture if it supports
384           the API needed to access function ar    346           the API needed to access function arguments from pt_regs,
385           declared in asm/ptrace.h                347           declared in asm/ptrace.h
386                                                   348 
387 config HAVE_HW_BREAKPOINT                         349 config HAVE_HW_BREAKPOINT
388         bool                                      350         bool
389         depends on PERF_EVENTS                    351         depends on PERF_EVENTS
390                                                   352 
391 config HAVE_MIXED_BREAKPOINTS_REGS                353 config HAVE_MIXED_BREAKPOINTS_REGS
392         bool                                      354         bool
393         depends on HAVE_HW_BREAKPOINT             355         depends on HAVE_HW_BREAKPOINT
394         help                                      356         help
395           Depending on the arch implementation    357           Depending on the arch implementation of hardware breakpoints,
396           some of them have separate registers    358           some of them have separate registers for data and instruction
397           breakpoints addresses, others have m    359           breakpoints addresses, others have mixed registers to store
398           them but define the access type in a    360           them but define the access type in a control register.
399           Select this option if your arch impl    361           Select this option if your arch implements breakpoints under the
400           latter fashion.                         362           latter fashion.
401                                                   363 
402 config HAVE_USER_RETURN_NOTIFIER                  364 config HAVE_USER_RETURN_NOTIFIER
403         bool                                      365         bool
404                                                   366 
405 config HAVE_PERF_EVENTS_NMI                       367 config HAVE_PERF_EVENTS_NMI
406         bool                                      368         bool
407         help                                      369         help
408           System hardware can generate an NMI     370           System hardware can generate an NMI using the perf event
409           subsystem.  Also has support for cal    371           subsystem.  Also has support for calculating CPU cycle events
410           to determine how many clock cycles i    372           to determine how many clock cycles in a given period.
411                                                   373 
412 config HAVE_HARDLOCKUP_DETECTOR_PERF              374 config HAVE_HARDLOCKUP_DETECTOR_PERF
413         bool                                      375         bool
414         depends on HAVE_PERF_EVENTS_NMI           376         depends on HAVE_PERF_EVENTS_NMI
415         help                                      377         help
416           The arch chooses to use the generic     378           The arch chooses to use the generic perf-NMI-based hardlockup
417           detector. Must define HAVE_PERF_EVEN    379           detector. Must define HAVE_PERF_EVENTS_NMI.
418                                                   380 
419 config HAVE_HARDLOCKUP_DETECTOR_ARCH           !! 381 config HAVE_NMI_WATCHDOG
                                                   >> 382         depends on HAVE_NMI
420         bool                                      383         bool
421         help                                      384         help
422           The arch provides its own hardlockup !! 385           The arch provides a low level NMI watchdog. It provides
423           of the generic ones.                 !! 386           asm/nmi.h, and defines its own arch_touch_nmi_watchdog().
424                                                   387 
425           It uses the same command line parame !! 388 config HAVE_HARDLOCKUP_DETECTOR_ARCH
426           as the generic hardlockup detectors. !! 389         bool
                                                   >> 390         select HAVE_NMI_WATCHDOG
                                                   >> 391         help
                                                   >> 392           The arch chooses to provide its own hardlockup detector, which is
                                                   >> 393           a superset of the HAVE_NMI_WATCHDOG. It also conforms to config
                                                   >> 394           interfaces and parameters provided by hardlockup detector subsystem.
427                                                   395 
428 config HAVE_PERF_REGS                             396 config HAVE_PERF_REGS
429         bool                                      397         bool
430         help                                      398         help
431           Support selective register dumps for    399           Support selective register dumps for perf events. This includes
432           bit-mapping of each registers and a     400           bit-mapping of each registers and a unique architecture id.
433                                                   401 
434 config HAVE_PERF_USER_STACK_DUMP                  402 config HAVE_PERF_USER_STACK_DUMP
435         bool                                      403         bool
436         help                                      404         help
437           Support user stack dumps for perf ev    405           Support user stack dumps for perf event samples. This needs
438           access to the user stack pointer whi    406           access to the user stack pointer which is not unified across
439           architectures.                          407           architectures.
440                                                   408 
441 config HAVE_ARCH_JUMP_LABEL                       409 config HAVE_ARCH_JUMP_LABEL
442         bool                                      410         bool
443                                                   411 
444 config HAVE_ARCH_JUMP_LABEL_RELATIVE              412 config HAVE_ARCH_JUMP_LABEL_RELATIVE
445         bool                                      413         bool
446                                                   414 
447 config MMU_GATHER_TABLE_FREE                      415 config MMU_GATHER_TABLE_FREE
448         bool                                      416         bool
449                                                   417 
450 config MMU_GATHER_RCU_TABLE_FREE                  418 config MMU_GATHER_RCU_TABLE_FREE
451         bool                                      419         bool
452         select MMU_GATHER_TABLE_FREE              420         select MMU_GATHER_TABLE_FREE
453                                                   421 
454 config MMU_GATHER_PAGE_SIZE                       422 config MMU_GATHER_PAGE_SIZE
455         bool                                      423         bool
456                                                   424 
457 config MMU_GATHER_NO_RANGE                        425 config MMU_GATHER_NO_RANGE
458         bool                                      426         bool
459         select MMU_GATHER_MERGE_VMAS           << 
460                                                << 
461 config MMU_GATHER_NO_FLUSH_CACHE               << 
462         bool                                   << 
463                                                << 
464 config MMU_GATHER_MERGE_VMAS                   << 
465         bool                                   << 
466                                                   427 
467 config MMU_GATHER_NO_GATHER                       428 config MMU_GATHER_NO_GATHER
468         bool                                      429         bool
469         depends on MMU_GATHER_TABLE_FREE          430         depends on MMU_GATHER_TABLE_FREE
470                                                   431 
471 config ARCH_WANT_IRQS_OFF_ACTIVATE_MM             432 config ARCH_WANT_IRQS_OFF_ACTIVATE_MM
472         bool                                      433         bool
473         help                                      434         help
474           Temporary select until all architect    435           Temporary select until all architectures can be converted to have
475           irqs disabled over activate_mm. Arch    436           irqs disabled over activate_mm. Architectures that do IPI based TLB
476           shootdowns should enable this.          437           shootdowns should enable this.
477                                                   438 
478 # Use normal mm refcounting for MMU_LAZY_TLB k << 
479 # MMU_LAZY_TLB_REFCOUNT=n can improve the scal << 
480 # to/from kernel threads when the same mm is r << 
481 # multi-threaded application), by reducing con << 
482 #                                              << 
483 # This can be disabled if the architecture ens << 
484 # "lazy tlb" beyond its final refcount (i.e.,  << 
485 # or its kernel page tables). This could be ar << 
486 # final exit(2) TLB flush, for example.        << 
487 #                                              << 
488 # To implement this, an arch *must*:           << 
489 # Ensure the _lazy_tlb variants of mmgrab/mmdr << 
490 # the lazy tlb reference of a kthread's ->acti << 
491 # converted already).                          << 
492 config MMU_LAZY_TLB_REFCOUNT                   << 
493         def_bool y                             << 
494         depends on !MMU_LAZY_TLB_SHOOTDOWN     << 
495                                                << 
496 # This option allows MMU_LAZY_TLB_REFCOUNT=n.  << 
497 # mm as a lazy tlb beyond its last reference c << 
498 # users before the mm is deallocated. __mmdrop << 
499 # be using the mm as a lazy tlb, so that they  << 
500 # init_mm for their active mm. mm_cpumask(mm)  << 
501 # may be using mm as a lazy tlb mm.            << 
502 #                                              << 
503 # To implement this, an arch *must*:           << 
504 # - At the time of the final mmdrop of the mm, << 
505 #   at least all possible CPUs in which the mm << 
506 # - It must meet the requirements for MMU_LAZY << 
507 config MMU_LAZY_TLB_SHOOTDOWN                  << 
508         bool                                   << 
509                                                << 
510 config ARCH_HAVE_NMI_SAFE_CMPXCHG                 439 config ARCH_HAVE_NMI_SAFE_CMPXCHG
511         bool                                      440         bool
512                                                   441 
513 config ARCH_HAVE_EXTRA_ELF_NOTES               << 
514         bool                                   << 
515         help                                   << 
516           An architecture should select this i << 
517           arch-specific ELF note section to co << 
518           functions: elf_coredump_extra_notes_ << 
519           elf_coredump_extra_notes_write() whi << 
520           dumper.                              << 
521                                                << 
522 config ARCH_HAS_NMI_SAFE_THIS_CPU_OPS          << 
523         bool                                   << 
524                                                << 
525 config HAVE_ALIGNED_STRUCT_PAGE                   442 config HAVE_ALIGNED_STRUCT_PAGE
526         bool                                      443         bool
527         help                                      444         help
528           This makes sure that struct pages ar    445           This makes sure that struct pages are double word aligned and that
529           e.g. the SLUB allocator can perform     446           e.g. the SLUB allocator can perform double word atomic operations
530           on a struct page for better performa    447           on a struct page for better performance. However selecting this
531           might increase the size of a struct     448           might increase the size of a struct page by a word.
532                                                   449 
533 config HAVE_CMPXCHG_LOCAL                         450 config HAVE_CMPXCHG_LOCAL
534         bool                                      451         bool
535                                                   452 
536 config HAVE_CMPXCHG_DOUBLE                        453 config HAVE_CMPXCHG_DOUBLE
537         bool                                      454         bool
538                                                   455 
539 config ARCH_WEAK_RELEASE_ACQUIRE                  456 config ARCH_WEAK_RELEASE_ACQUIRE
540         bool                                      457         bool
541                                                   458 
542 config ARCH_WANT_IPC_PARSE_VERSION                459 config ARCH_WANT_IPC_PARSE_VERSION
543         bool                                      460         bool
544                                                   461 
545 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION         462 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
546         bool                                      463         bool
547                                                   464 
548 config ARCH_WANT_OLD_COMPAT_IPC                   465 config ARCH_WANT_OLD_COMPAT_IPC
549         select ARCH_WANT_COMPAT_IPC_PARSE_VERS    466         select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
550         bool                                      467         bool
551                                                   468 
552 config HAVE_ARCH_SECCOMP                          469 config HAVE_ARCH_SECCOMP
553         bool                                      470         bool
554         help                                      471         help
555           An arch should select this symbol to    472           An arch should select this symbol to support seccomp mode 1 (the fixed
556           syscall policy), and must provide an    473           syscall policy), and must provide an overrides for __NR_seccomp_sigreturn,
557           and compat syscalls if the asm-gener    474           and compat syscalls if the asm-generic/seccomp.h defaults need adjustment:
558           - __NR_seccomp_read_32                  475           - __NR_seccomp_read_32
559           - __NR_seccomp_write_32                 476           - __NR_seccomp_write_32
560           - __NR_seccomp_exit_32                  477           - __NR_seccomp_exit_32
561           - __NR_seccomp_sigreturn_32             478           - __NR_seccomp_sigreturn_32
562                                                   479 
563 config HAVE_ARCH_SECCOMP_FILTER                   480 config HAVE_ARCH_SECCOMP_FILTER
564         bool                                      481         bool
565         select HAVE_ARCH_SECCOMP                  482         select HAVE_ARCH_SECCOMP
566         help                                      483         help
567           An arch should select this symbol if    484           An arch should select this symbol if it provides all of these things:
568           - all the requirements for HAVE_ARCH    485           - all the requirements for HAVE_ARCH_SECCOMP
569           - syscall_get_arch()                    486           - syscall_get_arch()
570           - syscall_get_arguments()               487           - syscall_get_arguments()
571           - syscall_rollback()                    488           - syscall_rollback()
572           - syscall_set_return_value()            489           - syscall_set_return_value()
573           - SIGSYS siginfo_t support              490           - SIGSYS siginfo_t support
574           - secure_computing is called from a     491           - secure_computing is called from a ptrace_event()-safe context
575           - secure_computing return value is c    492           - secure_computing return value is checked and a return value of -1
576             results in the system call being s    493             results in the system call being skipped immediately.
577           - seccomp syscall wired up              494           - seccomp syscall wired up
578           - if !HAVE_SPARSE_SYSCALL_NR, have S    495           - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE,
579             SECCOMP_ARCH_NATIVE_NR, SECCOMP_AR    496             SECCOMP_ARCH_NATIVE_NR, SECCOMP_ARCH_NATIVE_NAME defined. If
580             COMPAT is supported, have the SECC    497             COMPAT is supported, have the SECCOMP_ARCH_COMPAT* defines too.
581                                                   498 
582 config SECCOMP                                    499 config SECCOMP
583         prompt "Enable seccomp to safely execu    500         prompt "Enable seccomp to safely execute untrusted bytecode"
584         def_bool y                                501         def_bool y
585         depends on HAVE_ARCH_SECCOMP              502         depends on HAVE_ARCH_SECCOMP
586         help                                      503         help
587           This kernel feature is useful for nu    504           This kernel feature is useful for number crunching applications
588           that may need to handle untrusted by    505           that may need to handle untrusted bytecode during their
589           execution. By using pipes or other t    506           execution. By using pipes or other transports made available
590           to the process as file descriptors s    507           to the process as file descriptors supporting the read/write
591           syscalls, it's possible to isolate t    508           syscalls, it's possible to isolate those applications in their
592           own address space using seccomp. Onc    509           own address space using seccomp. Once seccomp is enabled via
593           prctl(PR_SET_SECCOMP) or the seccomp    510           prctl(PR_SET_SECCOMP) or the seccomp() syscall, it cannot be
594           disabled and the task is only allowe    511           disabled and the task is only allowed to execute a few safe
595           syscalls defined by each seccomp mod    512           syscalls defined by each seccomp mode.
596                                                   513 
597           If unsure, say Y.                       514           If unsure, say Y.
598                                                   515 
599 config SECCOMP_FILTER                             516 config SECCOMP_FILTER
600         def_bool y                                517         def_bool y
601         depends on HAVE_ARCH_SECCOMP_FILTER &&    518         depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
602         help                                      519         help
603           Enable tasks to build secure computi    520           Enable tasks to build secure computing environments defined
604           in terms of Berkeley Packet Filter p    521           in terms of Berkeley Packet Filter programs which implement
605           task-defined system call filtering p    522           task-defined system call filtering polices.
606                                                   523 
607           See Documentation/userspace-api/secc    524           See Documentation/userspace-api/seccomp_filter.rst for details.
608                                                   525 
609 config SECCOMP_CACHE_DEBUG                        526 config SECCOMP_CACHE_DEBUG
610         bool "Show seccomp filter cache status    527         bool "Show seccomp filter cache status in /proc/pid/seccomp_cache"
611         depends on SECCOMP_FILTER && !HAVE_SPA    528         depends on SECCOMP_FILTER && !HAVE_SPARSE_SYSCALL_NR
612         depends on PROC_FS                        529         depends on PROC_FS
613         help                                      530         help
614           This enables the /proc/pid/seccomp_c    531           This enables the /proc/pid/seccomp_cache interface to monitor
615           seccomp cache data. The file format     532           seccomp cache data. The file format is subject to change. Reading
616           the file requires CAP_SYS_ADMIN.        533           the file requires CAP_SYS_ADMIN.
617                                                   534 
618           This option is for debugging only. E    535           This option is for debugging only. Enabling presents the risk that
619           an adversary may be able to infer th    536           an adversary may be able to infer the seccomp filter logic.
620                                                   537 
621           If unsure, say N.                       538           If unsure, say N.
622                                                   539 
623 config HAVE_ARCH_STACKLEAK                        540 config HAVE_ARCH_STACKLEAK
624         bool                                      541         bool
625         help                                      542         help
626           An architecture should select this i    543           An architecture should select this if it has the code which
627           fills the used part of the kernel st    544           fills the used part of the kernel stack with the STACKLEAK_POISON
628           value before returning from system c    545           value before returning from system calls.
629                                                   546 
630 config HAVE_STACKPROTECTOR                        547 config HAVE_STACKPROTECTOR
631         bool                                      548         bool
632         help                                      549         help
633           An arch should select this symbol if    550           An arch should select this symbol if:
634           - it has implemented a stack canary     551           - it has implemented a stack canary (e.g. __stack_chk_guard)
635                                                   552 
636 config STACKPROTECTOR                             553 config STACKPROTECTOR
637         bool "Stack Protector buffer overflow     554         bool "Stack Protector buffer overflow detection"
638         depends on HAVE_STACKPROTECTOR            555         depends on HAVE_STACKPROTECTOR
639         depends on $(cc-option,-fstack-protect    556         depends on $(cc-option,-fstack-protector)
640         default y                                 557         default y
641         help                                      558         help
642           This option turns on the "stack-prot    559           This option turns on the "stack-protector" GCC feature. This
643           feature puts, at the beginning of fu    560           feature puts, at the beginning of functions, a canary value on
644           the stack just before the return add    561           the stack just before the return address, and validates
645           the value just before actually retur    562           the value just before actually returning.  Stack based buffer
646           overflows (that need to overwrite th    563           overflows (that need to overwrite this return address) now also
647           overwrite the canary, which gets det    564           overwrite the canary, which gets detected and the attack is then
648           neutralized via a kernel panic.         565           neutralized via a kernel panic.
649                                                   566 
650           Functions will have the stack-protec    567           Functions will have the stack-protector canary logic added if they
651           have an 8-byte or larger character a    568           have an 8-byte or larger character array on the stack.
652                                                   569 
653           This feature requires gcc version 4.    570           This feature requires gcc version 4.2 or above, or a distribution
654           gcc with the feature backported ("-f    571           gcc with the feature backported ("-fstack-protector").
655                                                   572 
656           On an x86 "defconfig" build, this fe    573           On an x86 "defconfig" build, this feature adds canary checks to
657           about 3% of all kernel functions, wh    574           about 3% of all kernel functions, which increases kernel code size
658           by about 0.3%.                          575           by about 0.3%.
659                                                   576 
660 config STACKPROTECTOR_STRONG                      577 config STACKPROTECTOR_STRONG
661         bool "Strong Stack Protector"             578         bool "Strong Stack Protector"
662         depends on STACKPROTECTOR                 579         depends on STACKPROTECTOR
663         depends on $(cc-option,-fstack-protect    580         depends on $(cc-option,-fstack-protector-strong)
664         default y                                 581         default y
665         help                                      582         help
666           Functions will have the stack-protec    583           Functions will have the stack-protector canary logic added in any
667           of the following conditions:            584           of the following conditions:
668                                                   585 
669           - local variable's address used as p    586           - local variable's address used as part of the right hand side of an
670             assignment or function argument       587             assignment or function argument
671           - local variable is an array (or uni    588           - local variable is an array (or union containing an array),
672             regardless of array type or length    589             regardless of array type or length
673           - uses register local variables         590           - uses register local variables
674                                                   591 
675           This feature requires gcc version 4.    592           This feature requires gcc version 4.9 or above, or a distribution
676           gcc with the feature backported ("-f    593           gcc with the feature backported ("-fstack-protector-strong").
677                                                   594 
678           On an x86 "defconfig" build, this fe    595           On an x86 "defconfig" build, this feature adds canary checks to
679           about 20% of all kernel functions, w    596           about 20% of all kernel functions, which increases the kernel code
680           size by about 2%.                       597           size by about 2%.
681                                                   598 
682 config ARCH_SUPPORTS_SHADOW_CALL_STACK            599 config ARCH_SUPPORTS_SHADOW_CALL_STACK
683         bool                                      600         bool
684         help                                      601         help
685           An architecture should select this i !! 602           An architecture should select this if it supports Clang's Shadow
686           Shadow Call Stack and implements run !! 603           Call Stack and implements runtime support for shadow stack
687           switching.                              604           switching.
688                                                   605 
689 config SHADOW_CALL_STACK                          606 config SHADOW_CALL_STACK
690         bool "Shadow Call Stack"               !! 607         bool "Clang Shadow Call Stack"
691         depends on ARCH_SUPPORTS_SHADOW_CALL_S !! 608         depends on CC_IS_CLANG && ARCH_SUPPORTS_SHADOW_CALL_STACK
692         depends on DYNAMIC_FTRACE_WITH_ARGS || !! 609         depends on DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER
693         depends on MMU                         !! 610         help
694         help                                   !! 611           This option enables Clang's Shadow Call Stack, which uses a
695           This option enables the compiler's S !! 612           shadow stack to protect function return addresses from being
696           uses a shadow stack to protect funct !! 613           overwritten by an attacker. More information can be found in
697           being overwritten by an attacker. Mo !! 614           Clang's documentation:
698           in the compiler's documentation:     << 
699                                                   615 
700           - Clang: https://clang.llvm.org/docs !! 616             https://clang.llvm.org/docs/ShadowCallStack.html
701           - GCC: https://gcc.gnu.org/onlinedoc << 
702                                                   617 
703           Note that security guarantees in the    618           Note that security guarantees in the kernel differ from the
704           ones documented for user space. The     619           ones documented for user space. The kernel must store addresses
705           of shadow stacks in memory, which me    620           of shadow stacks in memory, which means an attacker capable of
706           reading and writing arbitrary memory    621           reading and writing arbitrary memory may be able to locate them
707           and hijack control flow by modifying    622           and hijack control flow by modifying the stacks.
708                                                   623 
709 config DYNAMIC_SCS                             << 
710         bool                                   << 
711         help                                   << 
712           Set by the arch code if it relies on << 
713           shadow call stack push and pop instr << 
714           compiler.                            << 
715                                                << 
716 config LTO                                        624 config LTO
717         bool                                      625         bool
718         help                                      626         help
719           Selected if the kernel will be built    627           Selected if the kernel will be built using the compiler's LTO feature.
720                                                   628 
721 config LTO_CLANG                                  629 config LTO_CLANG
722         bool                                      630         bool
723         select LTO                                631         select LTO
724         help                                      632         help
725           Selected if the kernel will be built    633           Selected if the kernel will be built using Clang's LTO feature.
726                                                   634 
727 config ARCH_SUPPORTS_LTO_CLANG                    635 config ARCH_SUPPORTS_LTO_CLANG
728         bool                                      636         bool
729         help                                      637         help
730           An architecture should select this o    638           An architecture should select this option if it supports:
731           - compiling with Clang,                 639           - compiling with Clang,
732           - compiling inline assembly with Cla    640           - compiling inline assembly with Clang's integrated assembler,
733           - and linking with LLD.                 641           - and linking with LLD.
734                                                   642 
735 config ARCH_SUPPORTS_LTO_CLANG_THIN               643 config ARCH_SUPPORTS_LTO_CLANG_THIN
736         bool                                      644         bool
737         help                                      645         help
738           An architecture should select this o    646           An architecture should select this option if it can support Clang's
739           ThinLTO mode.                           647           ThinLTO mode.
740                                                   648 
741 config HAS_LTO_CLANG                              649 config HAS_LTO_CLANG
742         def_bool y                                650         def_bool y
743         depends on CC_IS_CLANG && LD_IS_LLD && !! 651         # Clang >= 11: https://github.com/ClangBuiltLinux/linux/issues/510
                                                   >> 652         depends on CC_IS_CLANG && CLANG_VERSION >= 110000 && LD_IS_LLD && AS_IS_LLVM
744         depends on $(success,$(NM) --help | he    653         depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
745         depends on $(success,$(AR) --help | he    654         depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
746         depends on ARCH_SUPPORTS_LTO_CLANG        655         depends on ARCH_SUPPORTS_LTO_CLANG
747         depends on !FTRACE_MCOUNT_USE_RECORDMC    656         depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT
748         # https://github.com/ClangBuiltLinux/l !! 657         depends on !KASAN || KASAN_HW_TAGS
749         depends on (!KASAN || KASAN_HW_TAGS || << 
750         depends on (!KCOV || CLANG_VERSION >=  << 
751         depends on !GCOV_KERNEL                   658         depends on !GCOV_KERNEL
752         help                                      659         help
753           The compiler and Kconfig options sup    660           The compiler and Kconfig options support building with Clang's
754           LTO.                                    661           LTO.
755                                                   662 
756 choice                                            663 choice
757         prompt "Link Time Optimization (LTO)"     664         prompt "Link Time Optimization (LTO)"
758         default LTO_NONE                          665         default LTO_NONE
759         help                                      666         help
760           This option enables Link Time Optimi    667           This option enables Link Time Optimization (LTO), which allows the
761           compiler to optimize binaries global    668           compiler to optimize binaries globally.
762                                                   669 
763           If unsure, select LTO_NONE. Note tha    670           If unsure, select LTO_NONE. Note that LTO is very resource-intensive
764           so it's disabled by default.            671           so it's disabled by default.
765                                                   672 
766 config LTO_NONE                                   673 config LTO_NONE
767         bool "None"                               674         bool "None"
768         help                                      675         help
769           Build the kernel normally, without L    676           Build the kernel normally, without Link Time Optimization (LTO).
770                                                   677 
771 config LTO_CLANG_FULL                             678 config LTO_CLANG_FULL
772         bool "Clang Full LTO (EXPERIMENTAL)"      679         bool "Clang Full LTO (EXPERIMENTAL)"
773         depends on HAS_LTO_CLANG                  680         depends on HAS_LTO_CLANG
774         depends on !COMPILE_TEST                  681         depends on !COMPILE_TEST
775         select LTO_CLANG                          682         select LTO_CLANG
776         help                                      683         help
777           This option enables Clang's full Lin !! 684           This option enables Clang's full Link Time Optimization (LTO), which
778           allows the compiler to optimize the  !! 685           allows the compiler to optimize the kernel globally. If you enable
779           this option, the compiler generates  !! 686           this option, the compiler generates LLVM bitcode instead of ELF
780           object files, and the actual compila !! 687           object files, and the actual compilation from bitcode happens at
781           the LTO link step, which may take se !! 688           the LTO link step, which may take several minutes depending on the
782           kernel configuration. More informati !! 689           kernel configuration. More information can be found from LLVM's
783           documentation:                       !! 690           documentation:
784                                                   691 
785             https://llvm.org/docs/LinkTimeOpti    692             https://llvm.org/docs/LinkTimeOptimization.html
786                                                   693 
787           During link time, this option can us    694           During link time, this option can use a large amount of RAM, and
788           may take much longer than the ThinLT    695           may take much longer than the ThinLTO option.
789                                                   696 
790 config LTO_CLANG_THIN                             697 config LTO_CLANG_THIN
791         bool "Clang ThinLTO (EXPERIMENTAL)"       698         bool "Clang ThinLTO (EXPERIMENTAL)"
792         depends on HAS_LTO_CLANG && ARCH_SUPPO    699         depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN
793         select LTO_CLANG                          700         select LTO_CLANG
794         help                                      701         help
795           This option enables Clang's ThinLTO,    702           This option enables Clang's ThinLTO, which allows for parallel
796           optimization and faster incremental     703           optimization and faster incremental compiles compared to the
797           CONFIG_LTO_CLANG_FULL option. More i    704           CONFIG_LTO_CLANG_FULL option. More information can be found
798           from Clang's documentation:             705           from Clang's documentation:
799                                                   706 
800             https://clang.llvm.org/docs/ThinLT    707             https://clang.llvm.org/docs/ThinLTO.html
801                                                   708 
802           If unsure, say Y.                       709           If unsure, say Y.
803 endchoice                                         710 endchoice
804                                                   711 
805 config ARCH_SUPPORTS_CFI_CLANG                    712 config ARCH_SUPPORTS_CFI_CLANG
806         bool                                      713         bool
807         help                                      714         help
808           An architecture should select this o    715           An architecture should select this option if it can support Clang's
809           Control-Flow Integrity (CFI) checkin    716           Control-Flow Integrity (CFI) checking.
810                                                   717 
811 config ARCH_USES_CFI_TRAPS                     << 
812         bool                                   << 
813                                                << 
814 config CFI_CLANG                                  718 config CFI_CLANG
815         bool "Use Clang's Control Flow Integri    719         bool "Use Clang's Control Flow Integrity (CFI)"
816         depends on ARCH_SUPPORTS_CFI_CLANG     !! 720         depends on LTO_CLANG && ARCH_SUPPORTS_CFI_CLANG
817         depends on $(cc-option,-fsanitize=kcfi !! 721         # Clang >= 12:
                                                   >> 722         # - https://bugs.llvm.org/show_bug.cgi?id=46258
                                                   >> 723         # - https://bugs.llvm.org/show_bug.cgi?id=47479
                                                   >> 724         depends on CLANG_VERSION >= 120000
                                                   >> 725         select KALLSYMS
818         help                                      726         help
819           This option enables Clang's forward- !! 727           This option enables Clang’s forward-edge Control Flow Integrity
820           (CFI) checking, where the compiler i    728           (CFI) checking, where the compiler injects a runtime check to each
821           indirect function call to ensure the    729           indirect function call to ensure the target is a valid function with
822           the correct static type. This restri    730           the correct static type. This restricts possible call targets and
823           makes it more difficult for an attac    731           makes it more difficult for an attacker to exploit bugs that allow
824           the modification of stored function     732           the modification of stored function pointers. More information can be
825           found from Clang's documentation:       733           found from Clang's documentation:
826                                                   734 
827             https://clang.llvm.org/docs/Contro    735             https://clang.llvm.org/docs/ControlFlowIntegrity.html
828                                                   736 
                                                   >> 737 config CFI_CLANG_SHADOW
                                                   >> 738         bool "Use CFI shadow to speed up cross-module checks"
                                                   >> 739         default y
                                                   >> 740         depends on CFI_CLANG && MODULES
                                                   >> 741         help
                                                   >> 742           If you select this option, the kernel builds a fast look-up table of
                                                   >> 743           CFI check functions in loaded modules to reduce performance overhead.
                                                   >> 744 
                                                   >> 745           If unsure, say Y.
                                                   >> 746 
829 config CFI_PERMISSIVE                             747 config CFI_PERMISSIVE
830         bool "Use CFI in permissive mode"         748         bool "Use CFI in permissive mode"
831         depends on CFI_CLANG                      749         depends on CFI_CLANG
832         help                                      750         help
833           When selected, Control Flow Integrit    751           When selected, Control Flow Integrity (CFI) violations result in a
834           warning instead of a kernel panic. T    752           warning instead of a kernel panic. This option should only be used
835           for finding indirect call type misma    753           for finding indirect call type mismatches during development.
836                                                   754 
837           If unsure, say N.                       755           If unsure, say N.
838                                                   756 
839 config HAVE_ARCH_WITHIN_STACK_FRAMES              757 config HAVE_ARCH_WITHIN_STACK_FRAMES
840         bool                                      758         bool
841         help                                      759         help
842           An architecture should select this i    760           An architecture should select this if it can walk the kernel stack
843           frames to determine if an object is     761           frames to determine if an object is part of either the arguments
844           or local variables (i.e. that it exc    762           or local variables (i.e. that it excludes saved return addresses,
845           and similar) by implementing an inli    763           and similar) by implementing an inline arch_within_stack_frames(),
846           which is used by CONFIG_HARDENED_USE    764           which is used by CONFIG_HARDENED_USERCOPY.
847                                                   765 
848 config HAVE_CONTEXT_TRACKING_USER              !! 766 config HAVE_CONTEXT_TRACKING
849         bool                                      767         bool
850         help                                      768         help
851           Provide kernel/user boundaries probe    769           Provide kernel/user boundaries probes necessary for subsystems
852           that need it, such as userspace RCU     770           that need it, such as userspace RCU extended quiescent state.
853           Syscalls need to be wrapped inside u    771           Syscalls need to be wrapped inside user_exit()-user_enter(), either
854           optimized behind static key or throu    772           optimized behind static key or through the slow path using TIF_NOHZ
855           flag. Exceptions handlers must be wr    773           flag. Exceptions handlers must be wrapped as well. Irqs are already
856           protected inside ct_irq_enter/ct_irq !! 774           protected inside rcu_irq_enter/rcu_irq_exit() but preemption or signal
857           handling on irq exit still need to b    775           handling on irq exit still need to be protected.
858                                                   776 
859 config HAVE_CONTEXT_TRACKING_USER_OFFSTACK     !! 777 config HAVE_CONTEXT_TRACKING_OFFSTACK
860         bool                                      778         bool
861         help                                      779         help
862           Architecture neither relies on excep    780           Architecture neither relies on exception_enter()/exception_exit()
863           nor on schedule_user(). Also preempt    781           nor on schedule_user(). Also preempt_schedule_notrace() and
864           preempt_schedule_irq() can't be call    782           preempt_schedule_irq() can't be called in a preemptible section
865           while context tracking is CONTEXT_US    783           while context tracking is CONTEXT_USER. This feature reflects a sane
866           entry implementation where the follo    784           entry implementation where the following requirements are met on
867           critical entry code, ie: before user    785           critical entry code, ie: before user_exit() or after user_enter():
868                                                   786 
869           - Critical entry code isn't preempti    787           - Critical entry code isn't preemptible (or better yet:
870             not interruptible).                   788             not interruptible).
871           - No use of RCU read side critical s !! 789           - No use of RCU read side critical sections, unless rcu_nmi_enter()
872             got called.                           790             got called.
873           - No use of instrumentation, unless     791           - No use of instrumentation, unless instrumentation_begin() got
874             called.                               792             called.
875                                                   793 
876 config HAVE_TIF_NOHZ                              794 config HAVE_TIF_NOHZ
877         bool                                      795         bool
878         help                                      796         help
879           Arch relies on TIF_NOHZ and syscall     797           Arch relies on TIF_NOHZ and syscall slow path to implement context
880           tracking calls to user_enter()/user_    798           tracking calls to user_enter()/user_exit().
881                                                   799 
882 config HAVE_VIRT_CPU_ACCOUNTING                   800 config HAVE_VIRT_CPU_ACCOUNTING
883         bool                                      801         bool
884                                                   802 
885 config HAVE_VIRT_CPU_ACCOUNTING_IDLE              803 config HAVE_VIRT_CPU_ACCOUNTING_IDLE
886         bool                                      804         bool
887         help                                      805         help
888           Architecture has its own way to acco    806           Architecture has its own way to account idle CPU time and therefore
889           doesn't implement vtime_account_idle    807           doesn't implement vtime_account_idle().
890                                                   808 
891 config ARCH_HAS_SCALED_CPUTIME                    809 config ARCH_HAS_SCALED_CPUTIME
892         bool                                      810         bool
893                                                   811 
894 config HAVE_VIRT_CPU_ACCOUNTING_GEN               812 config HAVE_VIRT_CPU_ACCOUNTING_GEN
895         bool                                      813         bool
896         default y if 64BIT                        814         default y if 64BIT
897         help                                      815         help
898           With VIRT_CPU_ACCOUNTING_GEN, cputim    816           With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
899           Before enabling this option, arch co    817           Before enabling this option, arch code must be audited
900           to ensure there are no races in conc    818           to ensure there are no races in concurrent read/write of
901           cputime_t. For example, reading/writ    819           cputime_t. For example, reading/writing 64-bit cputime_t on
902           some 32-bit arches may require multi    820           some 32-bit arches may require multiple accesses, so proper
903           locking is needed to protect against    821           locking is needed to protect against concurrent accesses.
904                                                   822 
905 config HAVE_IRQ_TIME_ACCOUNTING                   823 config HAVE_IRQ_TIME_ACCOUNTING
906         bool                                      824         bool
907         help                                      825         help
908           Archs need to ensure they use a high    826           Archs need to ensure they use a high enough resolution clock to
909           support irq time accounting and then    827           support irq time accounting and then call enable_sched_clock_irqtime().
910                                                   828 
911 config HAVE_MOVE_PUD                              829 config HAVE_MOVE_PUD
912         bool                                      830         bool
913         help                                      831         help
914           Architectures that select this are a    832           Architectures that select this are able to move page tables at the
915           PUD level. If there are only 3 page     833           PUD level. If there are only 3 page table levels, the move effectively
916           happens at the PGD level.               834           happens at the PGD level.
917                                                   835 
918 config HAVE_MOVE_PMD                              836 config HAVE_MOVE_PMD
919         bool                                      837         bool
920         help                                      838         help
921           Archs that select this are able to m    839           Archs that select this are able to move page tables at the PMD level.
922                                                   840 
923 config HAVE_ARCH_TRANSPARENT_HUGEPAGE             841 config HAVE_ARCH_TRANSPARENT_HUGEPAGE
924         bool                                      842         bool
925                                                   843 
926 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD         844 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
927         bool                                      845         bool
928                                                   846 
929 config HAVE_ARCH_HUGE_VMAP                        847 config HAVE_ARCH_HUGE_VMAP
930         bool                                      848         bool
931                                                   849 
932 #                                                 850 #
933 #  Archs that select this would be capable of     851 #  Archs that select this would be capable of PMD-sized vmaps (i.e.,
934 #  arch_vmap_pmd_supported() returns true). Th !! 852 #  arch_vmap_pmd_supported() returns true), and they must make no assumptions
935 #  must be used to enable allocations to use h !! 853 #  that vmalloc memory is mapped with PAGE_SIZE ptes. The VM_NO_HUGE_VMAP flag
                                                   >> 854 #  can be used to prohibit arch-specific allocations from using hugepages to
                                                   >> 855 #  help with this (e.g., modules may require it).
936 #                                                 856 #
937 config HAVE_ARCH_HUGE_VMALLOC                     857 config HAVE_ARCH_HUGE_VMALLOC
938         depends on HAVE_ARCH_HUGE_VMAP            858         depends on HAVE_ARCH_HUGE_VMAP
939         bool                                      859         bool
940                                                   860 
941 config ARCH_WANT_HUGE_PMD_SHARE                   861 config ARCH_WANT_HUGE_PMD_SHARE
942         bool                                      862         bool
943                                                   863 
944 # Archs that want to use pmd_mkwrite on kernel << 
945 # if there are no userspace memory management  << 
946 config ARCH_WANT_KERNEL_PMD_MKWRITE            << 
947         bool                                   << 
948                                                << 
949 config ARCH_WANT_PMD_MKWRITE                   << 
950         def_bool TRANSPARENT_HUGEPAGE || ARCH_ << 
951                                                << 
952 config HAVE_ARCH_SOFT_DIRTY                       864 config HAVE_ARCH_SOFT_DIRTY
953         bool                                      865         bool
954                                                   866 
955 config HAVE_MOD_ARCH_SPECIFIC                     867 config HAVE_MOD_ARCH_SPECIFIC
956         bool                                      868         bool
957         help                                      869         help
958           The arch uses struct mod_arch_specif    870           The arch uses struct mod_arch_specific to store data.  Many arches
959           just need a simple module loader wit    871           just need a simple module loader without arch specific data - those
960           should not enable this.                 872           should not enable this.
961                                                   873 
962 config MODULES_USE_ELF_RELA                       874 config MODULES_USE_ELF_RELA
963         bool                                      875         bool
964         help                                      876         help
965           Modules only use ELF RELA relocation    877           Modules only use ELF RELA relocations.  Modules with ELF REL
966           relocations will give an error.         878           relocations will give an error.
967                                                   879 
968 config MODULES_USE_ELF_REL                        880 config MODULES_USE_ELF_REL
969         bool                                      881         bool
970         help                                      882         help
971           Modules only use ELF REL relocations    883           Modules only use ELF REL relocations.  Modules with ELF RELA
972           relocations will give an error.         884           relocations will give an error.
973                                                   885 
974 config ARCH_WANTS_MODULES_DATA_IN_VMALLOC      << 
975         bool                                   << 
976         help                                   << 
977           For architectures like powerpc/32 wh << 
978           allocation and need to allocate modu << 
979                                                << 
980 config ARCH_WANTS_EXECMEM_LATE                 << 
981         bool                                   << 
982         help                                   << 
983           For architectures that do not alloca << 
984           boot, but rather require its initial << 
985           enough entropy for module space rand << 
986           arm64.                               << 
987                                                << 
988 config HAVE_IRQ_EXIT_ON_IRQ_STACK                 886 config HAVE_IRQ_EXIT_ON_IRQ_STACK
989         bool                                      887         bool
990         help                                      888         help
991           Architecture doesn't only execute th    889           Architecture doesn't only execute the irq handler on the irq stack
992           but also irq_exit(). This way we can    890           but also irq_exit(). This way we can process softirqs on this irq
993           stack instead of switching to a new     891           stack instead of switching to a new one when we call __do_softirq()
994           in the end of an hardirq.               892           in the end of an hardirq.
995           This spares a stack switch and impro    893           This spares a stack switch and improves cache usage on softirq
996           processing.                             894           processing.
997                                                   895 
998 config HAVE_SOFTIRQ_ON_OWN_STACK                  896 config HAVE_SOFTIRQ_ON_OWN_STACK
999         bool                                      897         bool
1000         help                                     898         help
1001           Architecture provides a function to    899           Architecture provides a function to run __do_softirq() on a
1002           separate stack.                        900           separate stack.
1003                                                  901 
1004 config SOFTIRQ_ON_OWN_STACK                   << 
1005         def_bool HAVE_SOFTIRQ_ON_OWN_STACK && << 
1006                                               << 
1007 config ALTERNATE_USER_ADDRESS_SPACE           << 
1008         bool                                  << 
1009         help                                  << 
1010           Architectures set this when the CPU << 
1011           spaces for kernel and user space po << 
1012           access_ok() check on a __user point << 
1013                                               << 
1014 config PGTABLE_LEVELS                            902 config PGTABLE_LEVELS
1015         int                                      903         int
1016         default 2                                904         default 2
1017                                                  905 
1018 config ARCH_HAS_ELF_RANDOMIZE                    906 config ARCH_HAS_ELF_RANDOMIZE
1019         bool                                     907         bool
1020         help                                     908         help
1021           An architecture supports choosing r    909           An architecture supports choosing randomized locations for
1022           stack, mmap, brk, and ET_DYN. Defin    910           stack, mmap, brk, and ET_DYN. Defined functions:
1023           - arch_mmap_rnd()                      911           - arch_mmap_rnd()
1024           - arch_randomize_brk()                 912           - arch_randomize_brk()
1025                                                  913 
1026 config HAVE_ARCH_MMAP_RND_BITS                   914 config HAVE_ARCH_MMAP_RND_BITS
1027         bool                                     915         bool
1028         help                                     916         help
1029           An arch should select this symbol i    917           An arch should select this symbol if it supports setting a variable
1030           number of bits for use in establish    918           number of bits for use in establishing the base address for mmap
1031           allocations, has MMU enabled and pr    919           allocations, has MMU enabled and provides values for both:
1032           - ARCH_MMAP_RND_BITS_MIN               920           - ARCH_MMAP_RND_BITS_MIN
1033           - ARCH_MMAP_RND_BITS_MAX               921           - ARCH_MMAP_RND_BITS_MAX
1034                                                  922 
1035 config HAVE_EXIT_THREAD                          923 config HAVE_EXIT_THREAD
1036         bool                                     924         bool
1037         help                                     925         help
1038           An architecture implements exit_thr    926           An architecture implements exit_thread.
1039                                                  927 
1040 config ARCH_MMAP_RND_BITS_MIN                    928 config ARCH_MMAP_RND_BITS_MIN
1041         int                                      929         int
1042                                                  930 
1043 config ARCH_MMAP_RND_BITS_MAX                    931 config ARCH_MMAP_RND_BITS_MAX
1044         int                                      932         int
1045                                                  933 
1046 config ARCH_MMAP_RND_BITS_DEFAULT                934 config ARCH_MMAP_RND_BITS_DEFAULT
1047         int                                      935         int
1048                                                  936 
1049 config ARCH_MMAP_RND_BITS                        937 config ARCH_MMAP_RND_BITS
1050         int "Number of bits to use for ASLR o    938         int "Number of bits to use for ASLR of mmap base address" if EXPERT
1051         range ARCH_MMAP_RND_BITS_MIN ARCH_MMA    939         range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
1052         default ARCH_MMAP_RND_BITS_DEFAULT if    940         default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
1053         default ARCH_MMAP_RND_BITS_MIN           941         default ARCH_MMAP_RND_BITS_MIN
1054         depends on HAVE_ARCH_MMAP_RND_BITS       942         depends on HAVE_ARCH_MMAP_RND_BITS
1055         help                                     943         help
1056           This value can be used to select th    944           This value can be used to select the number of bits to use to
1057           determine the random offset to the     945           determine the random offset to the base address of vma regions
1058           resulting from mmap allocations. Th    946           resulting from mmap allocations. This value will be bounded
1059           by the architecture's minimum and m    947           by the architecture's minimum and maximum supported values.
1060                                                  948 
1061           This value can be changed after boo    949           This value can be changed after boot using the
1062           /proc/sys/vm/mmap_rnd_bits tunable     950           /proc/sys/vm/mmap_rnd_bits tunable
1063                                                  951 
1064 config HAVE_ARCH_MMAP_RND_COMPAT_BITS            952 config HAVE_ARCH_MMAP_RND_COMPAT_BITS
1065         bool                                     953         bool
1066         help                                     954         help
1067           An arch should select this symbol i    955           An arch should select this symbol if it supports running applications
1068           in compatibility mode, supports set    956           in compatibility mode, supports setting a variable number of bits for
1069           use in establishing the base addres    957           use in establishing the base address for mmap allocations, has MMU
1070           enabled and provides values for bot    958           enabled and provides values for both:
1071           - ARCH_MMAP_RND_COMPAT_BITS_MIN        959           - ARCH_MMAP_RND_COMPAT_BITS_MIN
1072           - ARCH_MMAP_RND_COMPAT_BITS_MAX        960           - ARCH_MMAP_RND_COMPAT_BITS_MAX
1073                                                  961 
1074 config ARCH_MMAP_RND_COMPAT_BITS_MIN             962 config ARCH_MMAP_RND_COMPAT_BITS_MIN
1075         int                                      963         int
1076                                                  964 
1077 config ARCH_MMAP_RND_COMPAT_BITS_MAX             965 config ARCH_MMAP_RND_COMPAT_BITS_MAX
1078         int                                      966         int
1079                                                  967 
1080 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT         968 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1081         int                                      969         int
1082                                                  970 
1083 config ARCH_MMAP_RND_COMPAT_BITS                 971 config ARCH_MMAP_RND_COMPAT_BITS
1084         int "Number of bits to use for ASLR o    972         int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
1085         range ARCH_MMAP_RND_COMPAT_BITS_MIN A    973         range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
1086         default ARCH_MMAP_RND_COMPAT_BITS_DEF    974         default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1087         default ARCH_MMAP_RND_COMPAT_BITS_MIN    975         default ARCH_MMAP_RND_COMPAT_BITS_MIN
1088         depends on HAVE_ARCH_MMAP_RND_COMPAT_    976         depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
1089         help                                     977         help
1090           This value can be used to select th    978           This value can be used to select the number of bits to use to
1091           determine the random offset to the     979           determine the random offset to the base address of vma regions
1092           resulting from mmap allocations for    980           resulting from mmap allocations for compatible applications This
1093           value will be bounded by the archit    981           value will be bounded by the architecture's minimum and maximum
1094           supported values.                      982           supported values.
1095                                                  983 
1096           This value can be changed after boo    984           This value can be changed after boot using the
1097           /proc/sys/vm/mmap_rnd_compat_bits t    985           /proc/sys/vm/mmap_rnd_compat_bits tunable
1098                                                  986 
1099 config HAVE_ARCH_COMPAT_MMAP_BASES               987 config HAVE_ARCH_COMPAT_MMAP_BASES
1100         bool                                     988         bool
1101         help                                     989         help
1102           This allows 64bit applications to i    990           This allows 64bit applications to invoke 32-bit mmap() syscall
1103           and vice-versa 32-bit applications     991           and vice-versa 32-bit applications to call 64-bit mmap().
1104           Required for applications doing dif    992           Required for applications doing different bitness syscalls.
1105                                                  993 
1106 config HAVE_PAGE_SIZE_4KB                     << 
1107         bool                                  << 
1108                                               << 
1109 config HAVE_PAGE_SIZE_8KB                     << 
1110         bool                                  << 
1111                                               << 
1112 config HAVE_PAGE_SIZE_16KB                    << 
1113         bool                                  << 
1114                                               << 
1115 config HAVE_PAGE_SIZE_32KB                    << 
1116         bool                                  << 
1117                                               << 
1118 config HAVE_PAGE_SIZE_64KB                    << 
1119         bool                                  << 
1120                                               << 
1121 config HAVE_PAGE_SIZE_256KB                   << 
1122         bool                                  << 
1123                                               << 
1124 choice                                        << 
1125         prompt "MMU page size"                << 
1126                                               << 
1127 config PAGE_SIZE_4KB                          << 
1128         bool "4KiB pages"                     << 
1129         depends on HAVE_PAGE_SIZE_4KB         << 
1130         help                                  << 
1131           This option select the standard 4Ki << 
1132           available option on many architectu << 
1133           minimize memory consumption and is  << 
1134           memory systems.                     << 
1135           Some software that is written for x << 
1136           assumptions about the page size and << 
1137                                               << 
1138 config PAGE_SIZE_8KB                          << 
1139         bool "8KiB pages"                     << 
1140         depends on HAVE_PAGE_SIZE_8KB         << 
1141         help                                  << 
1142           This option is the only supported p << 
1143           processors, and can be slightly fas << 
1144                                               << 
1145 config PAGE_SIZE_16KB                         << 
1146         bool "16KiB pages"                    << 
1147         depends on HAVE_PAGE_SIZE_16KB        << 
1148         help                                  << 
1149           This option is usually a good compr << 
1150           consumption and performance for typ << 
1151           workloads, often saving a level of  << 
1152           to 4KB pages as well as reducing TL << 
1153           per-page operations in the kernel a << 
1154           page cache.                         << 
1155                                               << 
1156 config PAGE_SIZE_32KB                         << 
1157         bool "32KiB pages"                    << 
1158         depends on HAVE_PAGE_SIZE_32KB        << 
1159         help                                  << 
1160           Using 32KiB page size will result i << 
1161           kernel at the price of higher memor << 
1162           16KiB pages.  This option is availa << 
1163           Note that you will need a suitable  << 
1164           support this.                       << 
1165                                               << 
1166 config PAGE_SIZE_64KB                         << 
1167         bool "64KiB pages"                    << 
1168         depends on HAVE_PAGE_SIZE_64KB        << 
1169         help                                  << 
1170           Using 64KiB page size will result i << 
1171           kernel at the price of much higher  << 
1172           4KiB or 16KiB pages.                << 
1173           This is not suitable for general-pu << 
1174           better performance may be worth the << 
1175           supercomputing or database applicat << 
1176           large in-memory data rather than sm << 
1177                                               << 
1178 config PAGE_SIZE_256KB                        << 
1179         bool "256KiB pages"                   << 
1180         depends on HAVE_PAGE_SIZE_256KB       << 
1181         help                                  << 
1182           256KiB pages have little practical  << 
1183           memory usage.  The kernel will only << 
1184           that have been compiled with '-zmax << 
1185           (the default is 64KiB or 4KiB on mo << 
1186                                               << 
1187 endchoice                                     << 
1188                                               << 
1189 config PAGE_SIZE_LESS_THAN_64KB                  994 config PAGE_SIZE_LESS_THAN_64KB
1190         def_bool y                               995         def_bool y
                                                   >> 996         depends on !ARM64_64K_PAGES
                                                   >> 997         depends on !IA64_PAGE_SIZE_64KB
1191         depends on !PAGE_SIZE_64KB               998         depends on !PAGE_SIZE_64KB
1192         depends on PAGE_SIZE_LESS_THAN_256KB  !! 999         depends on !PARISC_PAGE_SIZE_64KB
1193                                               !! 1000         depends on !PPC_64K_PAGES
1194 config PAGE_SIZE_LESS_THAN_256KB              !! 1001         depends on !PPC_256K_PAGES
1195         def_bool y                            << 
1196         depends on !PAGE_SIZE_256KB              1002         depends on !PAGE_SIZE_256KB
1197                                                  1003 
1198 config PAGE_SHIFT                             << 
1199         int                                   << 
1200         default 12 if PAGE_SIZE_4KB           << 
1201         default 13 if PAGE_SIZE_8KB           << 
1202         default 14 if PAGE_SIZE_16KB          << 
1203         default 15 if PAGE_SIZE_32KB          << 
1204         default 16 if PAGE_SIZE_64KB          << 
1205         default 18 if PAGE_SIZE_256KB         << 
1206                                               << 
1207 # This allows to use a set of generic functio    1004 # This allows to use a set of generic functions to determine mmap base
1208 # address by giving priority to top-down sche    1005 # address by giving priority to top-down scheme only if the process
1209 # is not in legacy mode (compat task, unlimit    1006 # is not in legacy mode (compat task, unlimited stack size or
1210 # sysctl_legacy_va_layout).                      1007 # sysctl_legacy_va_layout).
1211 # Architecture that selects this option can p    1008 # Architecture that selects this option can provide its own version of:
1212 # - STACK_RND_MASK                               1009 # - STACK_RND_MASK
1213 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT     1010 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
1214         bool                                     1011         bool
1215         depends on MMU                           1012         depends on MMU
1216         select ARCH_HAS_ELF_RANDOMIZE            1013         select ARCH_HAS_ELF_RANDOMIZE
1217                                                  1014 
1218 config HAVE_OBJTOOL                           << 
1219         bool                                  << 
1220                                               << 
1221 config HAVE_JUMP_LABEL_HACK                   << 
1222         bool                                  << 
1223                                               << 
1224 config HAVE_NOINSTR_HACK                      << 
1225         bool                                  << 
1226                                               << 
1227 config HAVE_NOINSTR_VALIDATION                << 
1228         bool                                  << 
1229                                               << 
1230 config HAVE_UACCESS_VALIDATION                << 
1231         bool                                  << 
1232         select OBJTOOL                        << 
1233                                               << 
1234 config HAVE_STACK_VALIDATION                     1015 config HAVE_STACK_VALIDATION
1235         bool                                     1016         bool
1236         help                                     1017         help
1237           Architecture supports objtool compi !! 1018           Architecture supports the 'objtool check' host tool command, which
1238           validation.                         !! 1019           performs compile-time stack metadata validation.
1239                                                  1020 
1240 config HAVE_RELIABLE_STACKTRACE                  1021 config HAVE_RELIABLE_STACKTRACE
1241         bool                                     1022         bool
1242         help                                     1023         help
1243           Architecture has either save_stack_    1024           Architecture has either save_stack_trace_tsk_reliable() or
1244           arch_stack_walk_reliable() function    1025           arch_stack_walk_reliable() function which only returns a stack trace
1245           if it can guarantee the trace is re    1026           if it can guarantee the trace is reliable.
1246                                                  1027 
1247 config HAVE_ARCH_HASH                            1028 config HAVE_ARCH_HASH
1248         bool                                     1029         bool
1249         default n                                1030         default n
1250         help                                     1031         help
1251           If this is set, the architecture pr    1032           If this is set, the architecture provides an <asm/hash.h>
1252           file which provides platform-specif    1033           file which provides platform-specific implementations of some
1253           functions in <linux/hash.h> or fs/n    1034           functions in <linux/hash.h> or fs/namei.c.
1254                                                  1035 
1255 config HAVE_ARCH_NVRAM_OPS                       1036 config HAVE_ARCH_NVRAM_OPS
1256         bool                                     1037         bool
1257                                                  1038 
1258 config ISA_BUS_API                               1039 config ISA_BUS_API
1259         def_bool ISA                             1040         def_bool ISA
1260                                                  1041 
1261 #                                                1042 #
1262 # ABI hall of shame                              1043 # ABI hall of shame
1263 #                                                1044 #
1264 config CLONE_BACKWARDS                           1045 config CLONE_BACKWARDS
1265         bool                                     1046         bool
1266         help                                     1047         help
1267           Architecture has tls passed as the     1048           Architecture has tls passed as the 4th argument of clone(2),
1268           not the 5th one.                       1049           not the 5th one.
1269                                                  1050 
1270 config CLONE_BACKWARDS2                          1051 config CLONE_BACKWARDS2
1271         bool                                     1052         bool
1272         help                                     1053         help
1273           Architecture has the first two argu    1054           Architecture has the first two arguments of clone(2) swapped.
1274                                                  1055 
1275 config CLONE_BACKWARDS3                          1056 config CLONE_BACKWARDS3
1276         bool                                     1057         bool
1277         help                                     1058         help
1278           Architecture has tls passed as the     1059           Architecture has tls passed as the 3rd argument of clone(2),
1279           not the 5th one.                       1060           not the 5th one.
1280                                                  1061 
1281 config ODD_RT_SIGACTION                          1062 config ODD_RT_SIGACTION
1282         bool                                     1063         bool
1283         help                                     1064         help
1284           Architecture has unusual rt_sigacti    1065           Architecture has unusual rt_sigaction(2) arguments
1285                                                  1066 
1286 config OLD_SIGSUSPEND                            1067 config OLD_SIGSUSPEND
1287         bool                                     1068         bool
1288         help                                     1069         help
1289           Architecture has old sigsuspend(2)     1070           Architecture has old sigsuspend(2) syscall, of one-argument variety
1290                                                  1071 
1291 config OLD_SIGSUSPEND3                           1072 config OLD_SIGSUSPEND3
1292         bool                                     1073         bool
1293         help                                     1074         help
1294           Even weirder antique ABI - three-ar    1075           Even weirder antique ABI - three-argument sigsuspend(2)
1295                                                  1076 
1296 config OLD_SIGACTION                             1077 config OLD_SIGACTION
1297         bool                                     1078         bool
1298         help                                     1079         help
1299           Architecture has old sigaction(2) s    1080           Architecture has old sigaction(2) syscall.  Nope, not the same
1300           as OLD_SIGSUSPEND | OLD_SIGSUSPEND3    1081           as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
1301           but fairly different variant of sig    1082           but fairly different variant of sigaction(2), thanks to OSF/1
1302           compatibility...                       1083           compatibility...
1303                                                  1084 
1304 config COMPAT_OLD_SIGACTION                      1085 config COMPAT_OLD_SIGACTION
1305         bool                                     1086         bool
1306                                                  1087 
1307 config COMPAT_32BIT_TIME                         1088 config COMPAT_32BIT_TIME
1308         bool "Provide system calls for 32-bit    1089         bool "Provide system calls for 32-bit time_t"
1309         default !64BIT || COMPAT                 1090         default !64BIT || COMPAT
1310         help                                     1091         help
1311           This enables 32 bit time_t support     1092           This enables 32 bit time_t support in addition to 64 bit time_t support.
1312           This is relevant on all 32-bit arch    1093           This is relevant on all 32-bit architectures, and 64-bit architectures
1313           as part of compat syscall handling.    1094           as part of compat syscall handling.
1314                                                  1095 
1315 config ARCH_NO_PREEMPT                           1096 config ARCH_NO_PREEMPT
1316         bool                                     1097         bool
1317                                                  1098 
                                                   >> 1099 config ARCH_EPHEMERAL_INODES
                                                   >> 1100         def_bool n
                                                   >> 1101         help
                                                   >> 1102           An arch should select this symbol if it doesn't keep track of inode
                                                   >> 1103           instances on its own, but instead relies on something else (e.g. the
                                                   >> 1104           host kernel for an UML kernel).
                                                   >> 1105 
1318 config ARCH_SUPPORTS_RT                          1106 config ARCH_SUPPORTS_RT
1319         bool                                     1107         bool
1320                                                  1108 
1321 config CPU_NO_EFFICIENT_FFS                      1109 config CPU_NO_EFFICIENT_FFS
1322         def_bool n                               1110         def_bool n
1323                                                  1111 
1324 config HAVE_ARCH_VMAP_STACK                      1112 config HAVE_ARCH_VMAP_STACK
1325         def_bool n                               1113         def_bool n
1326         help                                     1114         help
1327           An arch should select this symbol i    1115           An arch should select this symbol if it can support kernel stacks
1328           in vmalloc space.  This means:         1116           in vmalloc space.  This means:
1329                                                  1117 
1330           - vmalloc space must be large enoug    1118           - vmalloc space must be large enough to hold many kernel stacks.
1331             This may rule out many 32-bit arc    1119             This may rule out many 32-bit architectures.
1332                                                  1120 
1333           - Stacks in vmalloc space need to w    1121           - Stacks in vmalloc space need to work reliably.  For example, if
1334             vmap page tables are created on d    1122             vmap page tables are created on demand, either this mechanism
1335             needs to work while the stack poi    1123             needs to work while the stack points to a virtual address with
1336             unpopulated page tables or arch c    1124             unpopulated page tables or arch code (switch_to() and switch_mm(),
1337             most likely) needs to ensure that    1125             most likely) needs to ensure that the stack's page table entries
1338             are populated before running on a    1126             are populated before running on a possibly unpopulated stack.
1339                                                  1127 
1340           - If the stack overflows into a gua    1128           - If the stack overflows into a guard page, something reasonable
1341             should happen.  The definition of    1129             should happen.  The definition of "reasonable" is flexible, but
1342             instantly rebooting without loggi    1130             instantly rebooting without logging anything would be unfriendly.
1343                                                  1131 
1344 config VMAP_STACK                                1132 config VMAP_STACK
1345         default y                                1133         default y
1346         bool "Use a virtually-mapped stack"      1134         bool "Use a virtually-mapped stack"
1347         depends on HAVE_ARCH_VMAP_STACK          1135         depends on HAVE_ARCH_VMAP_STACK
1348         depends on !KASAN || KASAN_HW_TAGS ||    1136         depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC
1349         help                                     1137         help
1350           Enable this if you want the use vir    1138           Enable this if you want the use virtually-mapped kernel stacks
1351           with guard pages.  This causes kern    1139           with guard pages.  This causes kernel stack overflows to be
1352           caught immediately rather than caus    1140           caught immediately rather than causing difficult-to-diagnose
1353           corruption.                            1141           corruption.
1354                                                  1142 
1355           To use this with software KASAN mod    1143           To use this with software KASAN modes, the architecture must support
1356           backing virtual mappings with real     1144           backing virtual mappings with real shadow memory, and KASAN_VMALLOC
1357           must be enabled.                       1145           must be enabled.
1358                                                  1146 
1359 config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET         1147 config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
1360         def_bool n                               1148         def_bool n
1361         help                                     1149         help
1362           An arch should select this symbol i    1150           An arch should select this symbol if it can support kernel stack
1363           offset randomization with calls to     1151           offset randomization with calls to add_random_kstack_offset()
1364           during syscall entry and choose_ran    1152           during syscall entry and choose_random_kstack_offset() during
1365           syscall exit. Careful removal of -f    1153           syscall exit. Careful removal of -fstack-protector-strong and
1366           -fstack-protector should also be ap    1154           -fstack-protector should also be applied to the entry code and
1367           closely examined, as the artificial    1155           closely examined, as the artificial stack bump looks like an array
1368           to the compiler, so it will attempt    1156           to the compiler, so it will attempt to add canary checks regardless
1369           of the static branch state.            1157           of the static branch state.
1370                                                  1158 
1371 config RANDOMIZE_KSTACK_OFFSET                !! 1159 config RANDOMIZE_KSTACK_OFFSET_DEFAULT
1372         bool "Support for randomizing kernel  !! 1160         bool "Randomize kernel stack offset on syscall entry"
1373         default y                             << 
1374         depends on HAVE_ARCH_RANDOMIZE_KSTACK    1161         depends on HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
1375         depends on INIT_STACK_NONE || !CC_IS_    1162         depends on INIT_STACK_NONE || !CC_IS_CLANG || CLANG_VERSION >= 140000
1376         help                                     1163         help
1377           The kernel stack offset can be rand    1164           The kernel stack offset can be randomized (after pt_regs) by
1378           roughly 5 bits of entropy, frustrat    1165           roughly 5 bits of entropy, frustrating memory corruption
1379           attacks that depend on stack addres    1166           attacks that depend on stack address determinism or
1380           cross-syscall address exposures.    !! 1167           cross-syscall address exposures. This feature is controlled
1381                                               !! 1168           by kernel boot param "randomize_kstack_offset=on/off", and this
1382           The feature is controlled via the " !! 1169           config chooses the default boot state.
1383           kernel boot param, and if turned of << 
1384           of static branches (see JUMP_LABEL) << 
1385                                               << 
1386           If unsure, say Y.                   << 
1387                                               << 
1388 config RANDOMIZE_KSTACK_OFFSET_DEFAULT        << 
1389         bool "Default state of kernel stack o << 
1390         depends on RANDOMIZE_KSTACK_OFFSET    << 
1391         help                                  << 
1392           Kernel stack offset randomization i << 
1393           "randomize_kstack_offset=on/off", a << 
1394           boot state.                         << 
1395                                                  1170 
1396 config ARCH_OPTIONAL_KERNEL_RWX                  1171 config ARCH_OPTIONAL_KERNEL_RWX
1397         def_bool n                               1172         def_bool n
1398                                                  1173 
1399 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT          1174 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1400         def_bool n                               1175         def_bool n
1401                                                  1176 
1402 config ARCH_HAS_STRICT_KERNEL_RWX                1177 config ARCH_HAS_STRICT_KERNEL_RWX
1403         def_bool n                               1178         def_bool n
1404                                                  1179 
1405 config STRICT_KERNEL_RWX                         1180 config STRICT_KERNEL_RWX
1406         bool "Make kernel text and rodata rea    1181         bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
1407         depends on ARCH_HAS_STRICT_KERNEL_RWX    1182         depends on ARCH_HAS_STRICT_KERNEL_RWX
1408         default !ARCH_OPTIONAL_KERNEL_RWX ||     1183         default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1409         help                                     1184         help
1410           If this is set, kernel text and rod    1185           If this is set, kernel text and rodata memory will be made read-only,
1411           and non-text memory will be made no    1186           and non-text memory will be made non-executable. This provides
1412           protection against certain security    1187           protection against certain security exploits (e.g. executing the heap
1413           or modifying text)                     1188           or modifying text)
1414                                                  1189 
1415           These features are considered stand    1190           These features are considered standard security practice these days.
1416           You should say Y here in almost all    1191           You should say Y here in almost all cases.
1417                                                  1192 
1418 config ARCH_HAS_STRICT_MODULE_RWX                1193 config ARCH_HAS_STRICT_MODULE_RWX
1419         def_bool n                               1194         def_bool n
1420                                                  1195 
1421 config STRICT_MODULE_RWX                         1196 config STRICT_MODULE_RWX
1422         bool "Set loadable kernel module data    1197         bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX
1423         depends on ARCH_HAS_STRICT_MODULE_RWX    1198         depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES
1424         default !ARCH_OPTIONAL_KERNEL_RWX ||     1199         default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1425         help                                     1200         help
1426           If this is set, module text and rod    1201           If this is set, module text and rodata memory will be made read-only,
1427           and non-text memory will be made no    1202           and non-text memory will be made non-executable. This provides
1428           protection against certain security    1203           protection against certain security exploits (e.g. writing to text)
1429                                                  1204 
1430 # select if the architecture provides an asm/    1205 # select if the architecture provides an asm/dma-direct.h header
1431 config ARCH_HAS_PHYS_TO_DMA                      1206 config ARCH_HAS_PHYS_TO_DMA
1432         bool                                     1207         bool
1433                                                  1208 
1434 config HAVE_ARCH_COMPILER_H                      1209 config HAVE_ARCH_COMPILER_H
1435         bool                                     1210         bool
1436         help                                     1211         help
1437           An architecture can select this if     1212           An architecture can select this if it provides an
1438           asm/compiler.h header that should b    1213           asm/compiler.h header that should be included after
1439           linux/compiler-*.h in order to over    1214           linux/compiler-*.h in order to override macro definitions that those
1440           headers generally provide.             1215           headers generally provide.
1441                                                  1216 
1442 config HAVE_ARCH_PREL32_RELOCATIONS              1217 config HAVE_ARCH_PREL32_RELOCATIONS
1443         bool                                     1218         bool
1444         help                                     1219         help
1445           May be selected by an architecture     1220           May be selected by an architecture if it supports place-relative
1446           32-bit relocations, both in the too    1221           32-bit relocations, both in the toolchain and in the module loader,
1447           in which case relative references c    1222           in which case relative references can be used in special sections
1448           for PCI fixup, initcalls etc which     1223           for PCI fixup, initcalls etc which are only half the size on 64 bit
1449           architectures, and don't require ru    1224           architectures, and don't require runtime relocation on relocatable
1450           kernels.                               1225           kernels.
1451                                                  1226 
1452 config ARCH_USE_MEMREMAP_PROT                    1227 config ARCH_USE_MEMREMAP_PROT
1453         bool                                     1228         bool
1454                                                  1229 
1455 config LOCK_EVENT_COUNTS                         1230 config LOCK_EVENT_COUNTS
1456         bool "Locking event counts collection    1231         bool "Locking event counts collection"
1457         depends on DEBUG_FS                      1232         depends on DEBUG_FS
1458         help                                     1233         help
1459           Enable light-weight counting of var    1234           Enable light-weight counting of various locking related events
1460           in the system with minimal performa    1235           in the system with minimal performance impact. This reduces
1461           the chance of application behavior     1236           the chance of application behavior change because of timing
1462           differences. The counts are reporte    1237           differences. The counts are reported via debugfs.
1463                                                  1238 
1464 # Select if the architecture has support for     1239 # Select if the architecture has support for applying RELR relocations.
1465 config ARCH_HAS_RELR                             1240 config ARCH_HAS_RELR
1466         bool                                     1241         bool
1467                                                  1242 
1468 config RELR                                      1243 config RELR
1469         bool "Use RELR relocation packing"       1244         bool "Use RELR relocation packing"
1470         depends on ARCH_HAS_RELR && TOOLS_SUP    1245         depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR
1471         default y                                1246         default y
1472         help                                     1247         help
1473           Store the kernel's dynamic relocati    1248           Store the kernel's dynamic relocations in the RELR relocation packing
1474           format. Requires a compatible linke    1249           format. Requires a compatible linker (LLD supports this feature), as
1475           well as compatible NM and OBJCOPY u    1250           well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy
1476           are compatible).                       1251           are compatible).
1477                                                  1252 
1478 config ARCH_HAS_MEM_ENCRYPT                      1253 config ARCH_HAS_MEM_ENCRYPT
1479         bool                                     1254         bool
1480                                                  1255 
1481 config ARCH_HAS_CC_PLATFORM                      1256 config ARCH_HAS_CC_PLATFORM
1482         bool                                     1257         bool
1483                                                  1258 
1484 config HAVE_SPARSE_SYSCALL_NR                    1259 config HAVE_SPARSE_SYSCALL_NR
1485         bool                                  !! 1260        bool
1486         help                                  !! 1261        help
1487           An architecture should select this  !! 1262           An architecture should select this if its syscall numbering is sparse
1488           to save space. For example, MIPS ar    1263           to save space. For example, MIPS architecture has a syscall array with
1489           entries at 4000, 5000 and 6000 loca    1264           entries at 4000, 5000 and 6000 locations. This option turns on syscall
1490           related optimizations for a given a    1265           related optimizations for a given architecture.
1491                                                  1266 
1492 config ARCH_HAS_VDSO_DATA                        1267 config ARCH_HAS_VDSO_DATA
1493         bool                                     1268         bool
1494                                                  1269 
1495 config HAVE_STATIC_CALL                          1270 config HAVE_STATIC_CALL
1496         bool                                     1271         bool
1497                                                  1272 
1498 config HAVE_STATIC_CALL_INLINE                   1273 config HAVE_STATIC_CALL_INLINE
1499         bool                                     1274         bool
1500         depends on HAVE_STATIC_CALL              1275         depends on HAVE_STATIC_CALL
1501         select OBJTOOL                        << 
1502                                                  1276 
1503 config HAVE_PREEMPT_DYNAMIC                      1277 config HAVE_PREEMPT_DYNAMIC
1504         bool                                     1278         bool
1505                                               << 
1506 config HAVE_PREEMPT_DYNAMIC_CALL              << 
1507         bool                                  << 
1508         depends on HAVE_STATIC_CALL              1279         depends on HAVE_STATIC_CALL
1509         select HAVE_PREEMPT_DYNAMIC           !! 1280         depends on GENERIC_ENTRY
1510         help                                     1281         help
1511           An architecture should select this  !! 1282            Select this if the architecture support boot time preempt setting
1512           model being selected at boot time u !! 1283            on top of static calls. It is strongly advised to support inline
1513                                               !! 1284            static call to avoid any overhead.
1514           Where an architecture selects HAVE_ << 
1515           preemption function will be patched << 
1516                                               << 
1517           Where an architecture does not sele << 
1518           call to a preemption function will  << 
1519           trampoline will be patched.         << 
1520                                               << 
1521           It is strongly advised to support i << 
1522           overhead.                           << 
1523                                               << 
1524 config HAVE_PREEMPT_DYNAMIC_KEY               << 
1525         bool                                  << 
1526         depends on HAVE_ARCH_JUMP_LABEL       << 
1527         select HAVE_PREEMPT_DYNAMIC           << 
1528         help                                  << 
1529           An architecture should select this  << 
1530           model being selected at boot time u << 
1531                                               << 
1532           Each preemption function will be gi << 
1533           static key. This should have slight << 
1534           static calls, as this effectively i << 
1535           start of its callee. This may avoid << 
1536           integrate better with CFI schemes.  << 
1537                                               << 
1538           This will have greater overhead tha << 
1539           the call to the preemption function << 
1540                                                  1285 
1541 config ARCH_WANT_LD_ORPHAN_WARN                  1286 config ARCH_WANT_LD_ORPHAN_WARN
1542         bool                                     1287         bool
1543         help                                     1288         help
1544           An arch should select this symbol o    1289           An arch should select this symbol once all linker sections are explicitly
1545           included, size-asserted, or discard    1290           included, size-asserted, or discarded in the linker scripts. This is
1546           important because we never want exp    1291           important because we never want expected sections to be placed heuristically
1547           by the linker, since the locations     1292           by the linker, since the locations of such sections can change between linker
1548           versions.                              1293           versions.
1549                                                  1294 
1550 config HAVE_ARCH_PFN_VALID                       1295 config HAVE_ARCH_PFN_VALID
1551         bool                                     1296         bool
1552                                                  1297 
1553 config ARCH_SUPPORTS_DEBUG_PAGEALLOC             1298 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
1554         bool                                     1299         bool
1555                                                  1300 
1556 config ARCH_SUPPORTS_PAGE_TABLE_CHECK         << 
1557         bool                                  << 
1558                                               << 
1559 config ARCH_SPLIT_ARG64                          1301 config ARCH_SPLIT_ARG64
1560         bool                                     1302         bool
1561         help                                     1303         help
1562           If a 32-bit architecture requires 6 !! 1304            If a 32-bit architecture requires 64-bit arguments to be split into
1563           pairs of 32-bit arguments, select t !! 1305            pairs of 32-bit arguments, select this option.
1564                                                  1306 
1565 config ARCH_HAS_ELFCORE_COMPAT                   1307 config ARCH_HAS_ELFCORE_COMPAT
1566         bool                                     1308         bool
1567                                                  1309 
1568 config ARCH_HAS_PARANOID_L1D_FLUSH               1310 config ARCH_HAS_PARANOID_L1D_FLUSH
1569         bool                                     1311         bool
1570                                                  1312 
1571 config ARCH_HAVE_TRACE_MMIO_ACCESS            << 
1572         bool                                  << 
1573                                               << 
1574 config DYNAMIC_SIGFRAME                          1313 config DYNAMIC_SIGFRAME
1575         bool                                     1314         bool
1576                                                  1315 
1577 # Select, if arch has a named attribute group << 
1578 config HAVE_ARCH_NODE_DEV_GROUP               << 
1579         bool                                  << 
1580                                               << 
1581 config ARCH_HAS_HW_PTE_YOUNG                  << 
1582         bool                                  << 
1583         help                                  << 
1584           Architectures that select this opti << 
1585           accessed bit in PTE entries when us << 
1586           translations. Architectures that re << 
1587           this option and override arch_has_h << 
1588                                               << 
1589 config ARCH_HAS_NONLEAF_PMD_YOUNG             << 
1590         bool                                  << 
1591         help                                  << 
1592           Architectures that select this opti << 
1593           accessed bit in non-leaf PMD entrie << 
1594           address translations. Page table wa << 
1595           may use this capability to reduce t << 
1596                                               << 
1597 config ARCH_HAS_KERNEL_FPU_SUPPORT            << 
1598         bool                                  << 
1599         help                                  << 
1600           Architectures that select this opti << 
1601           the kernel, as described in Documen << 
1602                                               << 
1603 source "kernel/gcov/Kconfig"                     1316 source "kernel/gcov/Kconfig"
1604                                                  1317 
1605 source "scripts/gcc-plugins/Kconfig"             1318 source "scripts/gcc-plugins/Kconfig"
1606                                               << 
1607 config FUNCTION_ALIGNMENT_4B                  << 
1608         bool                                  << 
1609                                               << 
1610 config FUNCTION_ALIGNMENT_8B                  << 
1611         bool                                  << 
1612                                               << 
1613 config FUNCTION_ALIGNMENT_16B                 << 
1614         bool                                  << 
1615                                               << 
1616 config FUNCTION_ALIGNMENT_32B                 << 
1617         bool                                  << 
1618                                               << 
1619 config FUNCTION_ALIGNMENT_64B                 << 
1620         bool                                  << 
1621                                               << 
1622 config FUNCTION_ALIGNMENT                     << 
1623         int                                   << 
1624         default 64 if FUNCTION_ALIGNMENT_64B  << 
1625         default 32 if FUNCTION_ALIGNMENT_32B  << 
1626         default 16 if FUNCTION_ALIGNMENT_16B  << 
1627         default 8 if FUNCTION_ALIGNMENT_8B    << 
1628         default 4 if FUNCTION_ALIGNMENT_4B    << 
1629         default 0                             << 
1630                                               << 
1631 config CC_HAS_MIN_FUNCTION_ALIGNMENT          << 
1632         # Detect availability of the GCC opti << 
1633         # guarantees minimal alignment for al << 
1634         # -falign-functions which the compile << 
1635         def_bool $(cc-option, -fmin-function- << 
1636                                               << 
1637 config CC_HAS_SANE_FUNCTION_ALIGNMENT         << 
1638         # Set if the guaranteed alignment wit << 
1639         # available or extra care is required << 
1640         # strict alignment always, even with  << 
1641         def_bool CC_HAS_MIN_FUNCTION_ALIGNMEN << 
1642                                               << 
1643 config ARCH_NEED_CMPXCHG_1_EMU                << 
1644         bool                                  << 
1645                                                  1319 
1646 endmenu                                          1320 endmenu
                                                      

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