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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-5.2.21)


  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                                       15         bool
 24         help                                   << 
 25           Select if the architecture can check << 
 26           granularity (e.g. arm64 MTE). The pr << 
 27           must be implemented.                 << 
 28                                                    16 
 29 config HOTPLUG_SMT                             !!  17 config KEXEC_CORE
                                                   >>  18         select CRASH_CORE
 30         bool                                       19         bool
 31                                                    20 
 32 config SMT_NUM_THREADS_DYNAMIC                 !!  21 config HAVE_IMA_KEXEC
 33         bool                                       22         bool
 34                                                    23 
 35 # Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLU !!  24 config HOTPLUG_SMT
 36 config HOTPLUG_CORE_SYNC                       << 
 37         bool                                       25         bool
 38                                                    26 
 39 # Basic CPU dead synchronization selected by a !!  27 config OPROFILE
 40 config HOTPLUG_CORE_SYNC_DEAD                  !!  28         tristate "OProfile system profiling"
 41         bool                                   !!  29         depends on PROFILING
 42         select HOTPLUG_CORE_SYNC               !!  30         depends on HAVE_OPROFILE
                                                   >>  31         select RING_BUFFER
                                                   >>  32         select RING_BUFFER_ALLOW_SWAP
                                                   >>  33         help
                                                   >>  34           OProfile is a profiling system capable of profiling the
                                                   >>  35           whole system, include the kernel, kernel modules, libraries,
                                                   >>  36           and applications.
 43                                                    37 
 44 # Full CPU synchronization with alive state se !!  38           If unsure, say N.
 45 config HOTPLUG_CORE_SYNC_FULL                  << 
 46         bool                                   << 
 47         select HOTPLUG_CORE_SYNC_DEAD if HOTPL << 
 48         select HOTPLUG_CORE_SYNC               << 
 49                                                    39 
 50 config HOTPLUG_SPLIT_STARTUP                   !!  40 config OPROFILE_EVENT_MULTIPLEX
 51         bool                                   !!  41         bool "OProfile multiplexing support (EXPERIMENTAL)"
 52         select HOTPLUG_CORE_SYNC_FULL          !!  42         default n
                                                   >>  43         depends on OPROFILE && X86
                                                   >>  44         help
                                                   >>  45           The number of hardware counters is limited. The multiplexing
                                                   >>  46           feature enables OProfile to gather more events than counters
                                                   >>  47           are provided by the hardware. This is realized by switching
                                                   >>  48           between events at a user specified time interval.
 53                                                    49 
 54 config HOTPLUG_PARALLEL                        !!  50           If unsure, say N.
 55         bool                                   << 
 56         select HOTPLUG_SPLIT_STARTUP           << 
 57                                                    51 
 58 config GENERIC_ENTRY                           !!  52 config HAVE_OPROFILE
 59         bool                                       53         bool
 60                                                    54 
                                                   >>  55 config OPROFILE_NMI_TIMER
                                                   >>  56         def_bool y
                                                   >>  57         depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64
                                                   >>  58 
 61 config KPROBES                                     59 config KPROBES
 62         bool "Kprobes"                             60         bool "Kprobes"
                                                   >>  61         depends on MODULES
 63         depends on HAVE_KPROBES                    62         depends on HAVE_KPROBES
 64         select KALLSYMS                            63         select KALLSYMS
 65         select EXECMEM                         << 
 66         select NEED_TASKS_RCU                  << 
 67         help                                       64         help
 68           Kprobes allows you to trap at almost     65           Kprobes allows you to trap at almost any kernel address and
 69           execute a callback function.  regist     66           execute a callback function.  register_kprobe() establishes
 70           a probepoint and specifies the callb     67           a probepoint and specifies the callback.  Kprobes is useful
 71           for kernel debugging, non-intrusive      68           for kernel debugging, non-intrusive instrumentation and testing.
 72           If in doubt, say "N".                    69           If in doubt, say "N".
 73                                                    70 
 74 config JUMP_LABEL                                  71 config JUMP_LABEL
 75         bool "Optimize very unlikely/likely br !!  72        bool "Optimize very unlikely/likely branches"
 76         depends on HAVE_ARCH_JUMP_LABEL        !!  73        depends on HAVE_ARCH_JUMP_LABEL
 77         select OBJTOOL if HAVE_JUMP_LABEL_HACK !!  74        depends on CC_HAS_ASM_GOTO
 78         help                                   !!  75        help
 79           This option enables a transparent br !!  76          This option enables a transparent branch optimization that
 80           makes certain almost-always-true or  !!  77          makes certain almost-always-true or almost-always-false branch
 81           conditions even cheaper to execute w !!  78          conditions even cheaper to execute within the kernel.
 82                                                !!  79 
 83           Certain performance-sensitive kernel !!  80          Certain performance-sensitive kernel code, such as trace points,
 84           scheduler functionality, networking  !!  81          scheduler functionality, networking code and KVM have such
 85           branches and include support for thi !!  82          branches and include support for this optimization technique.
 86                                                !!  83 
 87           If it is detected that the compiler  !!  84          If it is detected that the compiler has support for "asm goto",
 88           the kernel will compile such branche !!  85          the kernel will compile such branches with just a nop
 89           instruction. When the condition flag !!  86          instruction. When the condition flag is toggled to true, the
 90           nop will be converted to a jump inst !!  87          nop will be converted to a jump instruction to execute the
 91           conditional block of instructions.   !!  88          conditional block of instructions.
 92                                                !!  89 
 93           This technique lowers overhead and s !!  90          This technique lowers overhead and stress on the branch prediction
 94           of the processor and generally makes !!  91          of the processor and generally makes the kernel faster. The update
 95           of the condition is slower, but thos !!  92          of the condition is slower, but those are always very rare.
 96                                                    93 
 97           ( On 32-bit x86, the necessary optio !!  94          ( On 32-bit x86, the necessary options added to the compiler
 98             flags may increase the size of the !!  95            flags may increase the size of the kernel slightly. )
 99                                                    96 
100 config STATIC_KEYS_SELFTEST                        97 config STATIC_KEYS_SELFTEST
101         bool "Static key selftest"                 98         bool "Static key selftest"
102         depends on JUMP_LABEL                      99         depends on JUMP_LABEL
103         help                                      100         help
104           Boot time self-test of the branch pa    101           Boot time self-test of the branch patching code.
105                                                   102 
106 config STATIC_CALL_SELFTEST                    << 
107         bool "Static call selftest"            << 
108         depends on HAVE_STATIC_CALL            << 
109         help                                   << 
110           Boot time self-test of the call patc << 
111                                                << 
112 config OPTPROBES                                  103 config OPTPROBES
113         def_bool y                                104         def_bool y
114         depends on KPROBES && HAVE_OPTPROBES      105         depends on KPROBES && HAVE_OPTPROBES
115         select NEED_TASKS_RCU                  !! 106         select TASKS_RCU if PREEMPT
116                                                   107 
117 config KPROBES_ON_FTRACE                          108 config KPROBES_ON_FTRACE
118         def_bool y                                109         def_bool y
119         depends on KPROBES && HAVE_KPROBES_ON_    110         depends on KPROBES && HAVE_KPROBES_ON_FTRACE
120         depends on DYNAMIC_FTRACE_WITH_REGS       111         depends on DYNAMIC_FTRACE_WITH_REGS
121         help                                      112         help
122           If function tracer is enabled and th !! 113          If function tracer is enabled and the arch supports full
123           passing of pt_regs to function traci !! 114          passing of pt_regs to function tracing, then kprobes can
124           optimize on top of function tracing. !! 115          optimize on top of function tracing.
125                                                   116 
126 config UPROBES                                    117 config UPROBES
127         def_bool n                                118         def_bool n
128         depends on ARCH_SUPPORTS_UPROBES          119         depends on ARCH_SUPPORTS_UPROBES
129         help                                      120         help
130           Uprobes is the user-space counterpar    121           Uprobes is the user-space counterpart to kprobes: they
131           enable instrumentation applications     122           enable instrumentation applications (such as 'perf probe')
132           to establish unintrusive probes in u    123           to establish unintrusive probes in user-space binaries and
133           libraries, by executing handler func    124           libraries, by executing handler functions when the probes
134           are hit by user-space applications.     125           are hit by user-space applications.
135                                                   126 
136           ( These probes come in the form of s    127           ( These probes come in the form of single-byte breakpoints,
137             managed by the kernel and kept tra    128             managed by the kernel and kept transparent to the probed
138             application. )                        129             application. )
139                                                   130 
140 config HAVE_64BIT_ALIGNED_ACCESS                  131 config HAVE_64BIT_ALIGNED_ACCESS
141         def_bool 64BIT && !HAVE_EFFICIENT_UNAL    132         def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
142         help                                      133         help
143           Some architectures require 64 bit ac    134           Some architectures require 64 bit accesses to be 64 bit
144           aligned, which also requires structs    135           aligned, which also requires structs containing 64 bit values
145           to be 64 bit aligned too. This inclu    136           to be 64 bit aligned too. This includes some 32 bit
146           architectures which can do 64 bit ac    137           architectures which can do 64 bit accesses, as well as 64 bit
147           architectures without unaligned acce    138           architectures without unaligned access.
148                                                   139 
149           This symbol should be selected by an    140           This symbol should be selected by an architecture if 64 bit
150           accesses are required to be 64 bit a    141           accesses are required to be 64 bit aligned in this way even
151           though it is not a 64 bit architectu    142           though it is not a 64 bit architecture.
152                                                   143 
153           See Documentation/core-api/unaligned !! 144           See Documentation/unaligned-memory-access.txt for more
154           more information on the topic of una !! 145           information on the topic of unaligned memory accesses.
155                                                   146 
156 config HAVE_EFFICIENT_UNALIGNED_ACCESS            147 config HAVE_EFFICIENT_UNALIGNED_ACCESS
157         bool                                      148         bool
158         help                                      149         help
159           Some architectures are unable to per    150           Some architectures are unable to perform unaligned accesses
160           without the use of get_unaligned/put    151           without the use of get_unaligned/put_unaligned. Others are
161           unable to perform such accesses effi    152           unable to perform such accesses efficiently (e.g. trap on
162           unaligned access and require fixing     153           unaligned access and require fixing it up in the exception
163           handler.)                               154           handler.)
164                                                   155 
165           This symbol should be selected by an    156           This symbol should be selected by an architecture if it can
166           perform unaligned accesses efficient    157           perform unaligned accesses efficiently to allow different
167           code paths to be selected for these     158           code paths to be selected for these cases. Some network
168           drivers, for example, could opt to n    159           drivers, for example, could opt to not fix up alignment
169           problems with received packets if do    160           problems with received packets if doing so would not help
170           much.                                   161           much.
171                                                   162 
172           See Documentation/core-api/unaligned !! 163           See Documentation/unaligned-memory-access.txt for more
173           information on the topic of unaligne    164           information on the topic of unaligned memory accesses.
174                                                   165 
175 config ARCH_USE_BUILTIN_BSWAP                     166 config ARCH_USE_BUILTIN_BSWAP
176         bool                                   !! 167        bool
177         help                                   !! 168        help
178           Modern versions of GCC (since 4.4) h !! 169          Modern versions of GCC (since 4.4) have builtin functions
179           for handling byte-swapping. Using th !! 170          for handling byte-swapping. Using these, instead of the old
180           inline assembler that the architectu !! 171          inline assembler that the architecture code provides in the
181           __arch_bswapXX() macros, allows the  !! 172          __arch_bswapXX() macros, allows the compiler to see what's
182           happening and offers more opportunit !! 173          happening and offers more opportunity for optimisation. In
183           particular, the compiler will be abl !! 174          particular, the compiler will be able to combine the byteswap
184           with a nearby load or store and use  !! 175          with a nearby load or store and use load-and-swap or
185           store-and-swap instructions if the a !! 176          store-and-swap instructions if the architecture has them. It
186           should almost *never* result in code !! 177          should almost *never* result in code which is worse than the
187           hand-coded assembler in <asm/swab.h> !! 178          hand-coded assembler in <asm/swab.h>.  But just in case it
188           does, the use of the builtins is opt !! 179          does, the use of the builtins is optional.
189                                                !! 180 
190           Any architecture with load-and-swap  !! 181          Any architecture with load-and-swap or store-and-swap
191           instructions should set this. And it !! 182          instructions should set this. And it shouldn't hurt to set it
192           on architectures that don't have suc !! 183          on architectures that don't have such instructions.
193                                                   184 
194 config KRETPROBES                                 185 config KRETPROBES
195         def_bool y                                186         def_bool y
196         depends on KPROBES && (HAVE_KRETPROBES !! 187         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                                                   188 
204 config USER_RETURN_NOTIFIER                       189 config USER_RETURN_NOTIFIER
205         bool                                      190         bool
206         depends on HAVE_USER_RETURN_NOTIFIER      191         depends on HAVE_USER_RETURN_NOTIFIER
207         help                                      192         help
208           Provide a kernel-internal notificati    193           Provide a kernel-internal notification when a cpu is about to
209           switch to user mode.                    194           switch to user mode.
210                                                   195 
211 config HAVE_IOREMAP_PROT                          196 config HAVE_IOREMAP_PROT
212         bool                                      197         bool
213                                                   198 
214 config HAVE_KPROBES                               199 config HAVE_KPROBES
215         bool                                      200         bool
216                                                   201 
217 config HAVE_KRETPROBES                            202 config HAVE_KRETPROBES
218         bool                                      203         bool
219                                                   204 
220 config HAVE_OPTPROBES                             205 config HAVE_OPTPROBES
221         bool                                      206         bool
222                                                   207 
223 config HAVE_KPROBES_ON_FTRACE                     208 config HAVE_KPROBES_ON_FTRACE
224         bool                                      209         bool
225                                                   210 
226 config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE    << 
227         bool                                   << 
228         help                                   << 
229           Since kretprobes modifies return add << 
230           stacktrace may see the kretprobe tra << 
231           of correct one. If the architecture  << 
232           unwinder can adjust such entries, se << 
233                                                << 
234 config HAVE_FUNCTION_ERROR_INJECTION              211 config HAVE_FUNCTION_ERROR_INJECTION
235         bool                                      212         bool
236                                                   213 
237 config HAVE_NMI                                   214 config HAVE_NMI
238         bool                                      215         bool
239                                                   216 
240 config HAVE_FUNCTION_DESCRIPTORS               << 
241         bool                                   << 
242                                                << 
243 config TRACE_IRQFLAGS_SUPPORT                  << 
244         bool                                   << 
245                                                << 
246 config TRACE_IRQFLAGS_NMI_SUPPORT              << 
247         bool                                   << 
248                                                << 
249 #                                                 217 #
250 # An arch should select this if it provides al    218 # An arch should select this if it provides all these things:
251 #                                                 219 #
252 #       task_pt_regs()          in asm/process    220 #       task_pt_regs()          in asm/processor.h or asm/ptrace.h
253 #       arch_has_single_step()  if there is ha    221 #       arch_has_single_step()  if there is hardware single-step support
254 #       arch_has_block_step()   if there is ha    222 #       arch_has_block_step()   if there is hardware block-step support
255 #       asm/syscall.h           supplying asm-    223 #       asm/syscall.h           supplying asm-generic/syscall.h interface
256 #       linux/regset.h          user_regset in    224 #       linux/regset.h          user_regset interfaces
257 #       CORE_DUMP_USE_REGSET    #define'd in l    225 #       CORE_DUMP_USE_REGSET    #define'd in linux/elf.h
258 #       TIF_SYSCALL_TRACE       calls ptrace_r !! 226 #       TIF_SYSCALL_TRACE       calls tracehook_report_syscall_{entry,exit}
259 #       TIF_NOTIFY_RESUME       calls resume_u !! 227 #       TIF_NOTIFY_RESUME       calls tracehook_notify_resume()
                                                   >> 228 #       signal delivery         calls tracehook_signal_handler()
260 #                                                 229 #
261 config HAVE_ARCH_TRACEHOOK                        230 config HAVE_ARCH_TRACEHOOK
262         bool                                      231         bool
263                                                   232 
264 config HAVE_DMA_CONTIGUOUS                        233 config HAVE_DMA_CONTIGUOUS
265         bool                                      234         bool
266                                                   235 
267 config GENERIC_SMP_IDLE_THREAD                    236 config GENERIC_SMP_IDLE_THREAD
268         bool                                   !! 237        bool
269                                                   238 
270 config GENERIC_IDLE_POLL_SETUP                    239 config GENERIC_IDLE_POLL_SETUP
271         bool                                   !! 240        bool
272                                                   241 
273 config ARCH_HAS_FORTIFY_SOURCE                    242 config ARCH_HAS_FORTIFY_SOURCE
274         bool                                      243         bool
275         help                                      244         help
276           An architecture should select this w    245           An architecture should select this when it can successfully
277           build and run with CONFIG_FORTIFY_SO    246           build and run with CONFIG_FORTIFY_SOURCE.
278                                                   247 
279 #                                                 248 #
280 # Select if the arch provides a historic keepi    249 # Select if the arch provides a historic keepinit alias for the retain_initrd
281 # command line option                             250 # command line option
282 #                                                 251 #
283 config ARCH_HAS_KEEPINITRD                        252 config ARCH_HAS_KEEPINITRD
284         bool                                      253         bool
285                                                   254 
286 # Select if arch has all set_memory_ro/rw/x/nx    255 # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
287 config ARCH_HAS_SET_MEMORY                        256 config ARCH_HAS_SET_MEMORY
288         bool                                      257         bool
289                                                   258 
290 # Select if arch has all set_direct_map_invali    259 # Select if arch has all set_direct_map_invalid/default() functions
291 config ARCH_HAS_SET_DIRECT_MAP                    260 config ARCH_HAS_SET_DIRECT_MAP
292         bool                                      261         bool
293                                                   262 
294 #                                              !! 263 # Select if arch init_task must go in the __init_task_data section
295 # Select if the architecture provides the arch !! 264 config ARCH_TASK_STRUCT_ON_STACK
296 # either provide an uncached segment alias for !! 265        bool
297 # to remap the page tables in place.           << 
298 #                                              << 
299 config ARCH_HAS_DMA_SET_UNCACHED               << 
300         bool                                   << 
301                                                   266 
302 #                                              !! 267 # Select if arch has its private alloc_task_struct() function
303 # Select if the architectures provides the arc !! 268 config ARCH_TASK_STRUCT_ALLOCATOR
304 # to undo an in-place page table remap for unc << 
305 #                                              << 
306 config ARCH_HAS_DMA_CLEAR_UNCACHED             << 
307         bool                                      269         bool
308                                                   270 
309 config ARCH_HAS_CPU_FINALIZE_INIT              << 
310         bool                                   << 
311                                                << 
312 # The architecture has a per-task state that i << 
313 config ARCH_HAS_CPU_PASID                      << 
314         bool                                   << 
315         select IOMMU_MM_DATA                   << 
316                                                << 
317 config HAVE_ARCH_THREAD_STRUCT_WHITELIST          271 config HAVE_ARCH_THREAD_STRUCT_WHITELIST
318         bool                                      272         bool
                                                   >> 273         depends on !ARCH_TASK_STRUCT_ALLOCATOR
319         help                                      274         help
320           An architecture should select this t    275           An architecture should select this to provide hardened usercopy
321           knowledge about what region of the t    276           knowledge about what region of the thread_struct should be
322           whitelisted for copying to userspace    277           whitelisted for copying to userspace. Normally this is only the
323           FPU registers. Specifically, arch_th    278           FPU registers. Specifically, arch_thread_struct_whitelist()
324           should be implemented. Without this,    279           should be implemented. Without this, the entire thread_struct
325           field in task_struct will be left wh    280           field in task_struct will be left whitelisted.
326                                                   281 
327 # Select if arch wants to size task_struct dyn !! 282 # Select if arch has its private alloc_thread_stack() function
328 config ARCH_WANTS_DYNAMIC_TASK_STRUCT          !! 283 config ARCH_THREAD_STACK_ALLOCATOR
329         bool                                      284         bool
330                                                   285 
331 config ARCH_WANTS_NO_INSTR                     !! 286 # Select if arch wants to size task_struct dynamically via arch_task_struct_size:
                                                   >> 287 config ARCH_WANTS_DYNAMIC_TASK_STRUCT
332         bool                                      288         bool
333         help                                   << 
334           An architecture should select this i << 
335           functions to denote that the toolcha << 
336           functions and is required for correc << 
337                                                   289 
338 config ARCH_32BIT_OFF_T                           290 config ARCH_32BIT_OFF_T
339         bool                                      291         bool
340         depends on !64BIT                         292         depends on !64BIT
341         help                                      293         help
342           All new 32-bit architectures should     294           All new 32-bit architectures should have 64-bit off_t type on
343           userspace side which corresponds to     295           userspace side which corresponds to the loff_t kernel type. This
344           is the requirement for modern ABIs.     296           is the requirement for modern ABIs. Some existing architectures
345           still support 32-bit off_t. This opt    297           still support 32-bit off_t. This option is enabled for all such
346           architectures explicitly.               298           architectures explicitly.
347                                                   299 
348 # Selected by 64 bit architectures which have  << 
349 config ARCH_32BIT_USTAT_F_TINODE               << 
350         bool                                   << 
351                                                << 
352 config HAVE_ASM_MODVERSIONS                    << 
353         bool                                   << 
354         help                                   << 
355           This symbol should be selected by an << 
356           <asm/asm-prototypes.h> to support th << 
357           exported from assembly code.         << 
358                                                << 
359 config HAVE_REGS_AND_STACK_ACCESS_API             300 config HAVE_REGS_AND_STACK_ACCESS_API
360         bool                                      301         bool
361         help                                      302         help
362           This symbol should be selected by an !! 303           This symbol should be selected by an architecure if it supports
363           the API needed to access registers a    304           the API needed to access registers and stack entries from pt_regs,
364           declared in asm/ptrace.h                305           declared in asm/ptrace.h
365           For example the kprobes-based event     306           For example the kprobes-based event tracer needs this API.
366                                                   307 
367 config HAVE_RSEQ                                  308 config HAVE_RSEQ
368         bool                                      309         bool
369         depends on HAVE_REGS_AND_STACK_ACCESS_    310         depends on HAVE_REGS_AND_STACK_ACCESS_API
370         help                                      311         help
371           This symbol should be selected by an    312           This symbol should be selected by an architecture if it
372           supports an implementation of restar    313           supports an implementation of restartable sequences.
373                                                   314 
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               315 config HAVE_FUNCTION_ARG_ACCESS_API
381         bool                                      316         bool
382         help                                      317         help
383           This symbol should be selected by an !! 318           This symbol should be selected by an architecure if it supports
384           the API needed to access function ar    319           the API needed to access function arguments from pt_regs,
385           declared in asm/ptrace.h                320           declared in asm/ptrace.h
386                                                   321 
                                                   >> 322 config HAVE_CLK
                                                   >> 323         bool
                                                   >> 324         help
                                                   >> 325           The <linux/clk.h> calls support software clock gating and
                                                   >> 326           thus are a key power management tool on many systems.
                                                   >> 327 
387 config HAVE_HW_BREAKPOINT                         328 config HAVE_HW_BREAKPOINT
388         bool                                      329         bool
389         depends on PERF_EVENTS                    330         depends on PERF_EVENTS
390                                                   331 
391 config HAVE_MIXED_BREAKPOINTS_REGS                332 config HAVE_MIXED_BREAKPOINTS_REGS
392         bool                                      333         bool
393         depends on HAVE_HW_BREAKPOINT             334         depends on HAVE_HW_BREAKPOINT
394         help                                      335         help
395           Depending on the arch implementation    336           Depending on the arch implementation of hardware breakpoints,
396           some of them have separate registers    337           some of them have separate registers for data and instruction
397           breakpoints addresses, others have m    338           breakpoints addresses, others have mixed registers to store
398           them but define the access type in a    339           them but define the access type in a control register.
399           Select this option if your arch impl    340           Select this option if your arch implements breakpoints under the
400           latter fashion.                         341           latter fashion.
401                                                   342 
402 config HAVE_USER_RETURN_NOTIFIER                  343 config HAVE_USER_RETURN_NOTIFIER
403         bool                                      344         bool
404                                                   345 
405 config HAVE_PERF_EVENTS_NMI                       346 config HAVE_PERF_EVENTS_NMI
406         bool                                      347         bool
407         help                                      348         help
408           System hardware can generate an NMI     349           System hardware can generate an NMI using the perf event
409           subsystem.  Also has support for cal    350           subsystem.  Also has support for calculating CPU cycle events
410           to determine how many clock cycles i    351           to determine how many clock cycles in a given period.
411                                                   352 
412 config HAVE_HARDLOCKUP_DETECTOR_PERF              353 config HAVE_HARDLOCKUP_DETECTOR_PERF
413         bool                                      354         bool
414         depends on HAVE_PERF_EVENTS_NMI           355         depends on HAVE_PERF_EVENTS_NMI
415         help                                      356         help
416           The arch chooses to use the generic     357           The arch chooses to use the generic perf-NMI-based hardlockup
417           detector. Must define HAVE_PERF_EVEN    358           detector. Must define HAVE_PERF_EVENTS_NMI.
418                                                   359 
419 config HAVE_HARDLOCKUP_DETECTOR_ARCH           !! 360 config HAVE_NMI_WATCHDOG
                                                   >> 361         depends on HAVE_NMI
420         bool                                      362         bool
421         help                                      363         help
422           The arch provides its own hardlockup !! 364           The arch provides a low level NMI watchdog. It provides
423           of the generic ones.                 !! 365           asm/nmi.h, and defines its own arch_touch_nmi_watchdog().
424                                                   366 
425           It uses the same command line parame !! 367 config HAVE_HARDLOCKUP_DETECTOR_ARCH
426           as the generic hardlockup detectors. !! 368         bool
                                                   >> 369         select HAVE_NMI_WATCHDOG
                                                   >> 370         help
                                                   >> 371           The arch chooses to provide its own hardlockup detector, which is
                                                   >> 372           a superset of the HAVE_NMI_WATCHDOG. It also conforms to config
                                                   >> 373           interfaces and parameters provided by hardlockup detector subsystem.
427                                                   374 
428 config HAVE_PERF_REGS                             375 config HAVE_PERF_REGS
429         bool                                      376         bool
430         help                                      377         help
431           Support selective register dumps for    378           Support selective register dumps for perf events. This includes
432           bit-mapping of each registers and a     379           bit-mapping of each registers and a unique architecture id.
433                                                   380 
434 config HAVE_PERF_USER_STACK_DUMP                  381 config HAVE_PERF_USER_STACK_DUMP
435         bool                                      382         bool
436         help                                      383         help
437           Support user stack dumps for perf ev    384           Support user stack dumps for perf event samples. This needs
438           access to the user stack pointer whi    385           access to the user stack pointer which is not unified across
439           architectures.                          386           architectures.
440                                                   387 
441 config HAVE_ARCH_JUMP_LABEL                       388 config HAVE_ARCH_JUMP_LABEL
442         bool                                      389         bool
443                                                   390 
444 config HAVE_ARCH_JUMP_LABEL_RELATIVE              391 config HAVE_ARCH_JUMP_LABEL_RELATIVE
445         bool                                      392         bool
446                                                   393 
447 config MMU_GATHER_TABLE_FREE                   !! 394 config HAVE_RCU_TABLE_FREE
448         bool                                      395         bool
449                                                   396 
450 config MMU_GATHER_RCU_TABLE_FREE               !! 397 config HAVE_RCU_TABLE_NO_INVALIDATE
451         bool                                      398         bool
452         select MMU_GATHER_TABLE_FREE           << 
453                                                   399 
454 config MMU_GATHER_PAGE_SIZE                    !! 400 config HAVE_MMU_GATHER_PAGE_SIZE
455         bool                                      401         bool
456                                                   402 
457 config MMU_GATHER_NO_RANGE                     !! 403 config HAVE_MMU_GATHER_NO_GATHER
458         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                                                << 
467 config MMU_GATHER_NO_GATHER                    << 
468         bool                                   << 
469         depends on MMU_GATHER_TABLE_FREE       << 
470                                                << 
471 config ARCH_WANT_IRQS_OFF_ACTIVATE_MM          << 
472         bool                                   << 
473         help                                   << 
474           Temporary select until all architect << 
475           irqs disabled over activate_mm. Arch << 
476           shootdowns should enable this.       << 
477                                                << 
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                                      404         bool
509                                                   405 
510 config ARCH_HAVE_NMI_SAFE_CMPXCHG                 406 config ARCH_HAVE_NMI_SAFE_CMPXCHG
511         bool                                      407         bool
512                                                   408 
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                   409 config HAVE_ALIGNED_STRUCT_PAGE
526         bool                                      410         bool
527         help                                      411         help
528           This makes sure that struct pages ar    412           This makes sure that struct pages are double word aligned and that
529           e.g. the SLUB allocator can perform     413           e.g. the SLUB allocator can perform double word atomic operations
530           on a struct page for better performa    414           on a struct page for better performance. However selecting this
531           might increase the size of a struct     415           might increase the size of a struct page by a word.
532                                                   416 
533 config HAVE_CMPXCHG_LOCAL                         417 config HAVE_CMPXCHG_LOCAL
534         bool                                      418         bool
535                                                   419 
536 config HAVE_CMPXCHG_DOUBLE                        420 config HAVE_CMPXCHG_DOUBLE
537         bool                                      421         bool
538                                                   422 
539 config ARCH_WEAK_RELEASE_ACQUIRE                  423 config ARCH_WEAK_RELEASE_ACQUIRE
540         bool                                      424         bool
541                                                   425 
542 config ARCH_WANT_IPC_PARSE_VERSION                426 config ARCH_WANT_IPC_PARSE_VERSION
543         bool                                      427         bool
544                                                   428 
545 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION         429 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
546         bool                                      430         bool
547                                                   431 
548 config ARCH_WANT_OLD_COMPAT_IPC                   432 config ARCH_WANT_OLD_COMPAT_IPC
549         select ARCH_WANT_COMPAT_IPC_PARSE_VERS    433         select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
550         bool                                      434         bool
551                                                   435 
552 config HAVE_ARCH_SECCOMP                       << 
553         bool                                   << 
554         help                                   << 
555           An arch should select this symbol to << 
556           syscall policy), and must provide an << 
557           and compat syscalls if the asm-gener << 
558           - __NR_seccomp_read_32               << 
559           - __NR_seccomp_write_32              << 
560           - __NR_seccomp_exit_32               << 
561           - __NR_seccomp_sigreturn_32          << 
562                                                << 
563 config HAVE_ARCH_SECCOMP_FILTER                   436 config HAVE_ARCH_SECCOMP_FILTER
564         bool                                      437         bool
565         select HAVE_ARCH_SECCOMP               << 
566         help                                      438         help
567           An arch should select this symbol if    439           An arch should select this symbol if it provides all of these things:
568           - all the requirements for HAVE_ARCH << 
569           - syscall_get_arch()                    440           - syscall_get_arch()
570           - syscall_get_arguments()               441           - syscall_get_arguments()
571           - syscall_rollback()                    442           - syscall_rollback()
572           - syscall_set_return_value()            443           - syscall_set_return_value()
573           - SIGSYS siginfo_t support              444           - SIGSYS siginfo_t support
574           - secure_computing is called from a     445           - secure_computing is called from a ptrace_event()-safe context
575           - secure_computing return value is c    446           - secure_computing return value is checked and a return value of -1
576             results in the system call being s    447             results in the system call being skipped immediately.
577           - seccomp syscall wired up              448           - seccomp syscall wired up
578           - if !HAVE_SPARSE_SYSCALL_NR, have S << 
579             SECCOMP_ARCH_NATIVE_NR, SECCOMP_AR << 
580             COMPAT is supported, have the SECC << 
581                                                << 
582 config SECCOMP                                 << 
583         prompt "Enable seccomp to safely execu << 
584         def_bool y                             << 
585         depends on HAVE_ARCH_SECCOMP           << 
586         help                                   << 
587           This kernel feature is useful for nu << 
588           that may need to handle untrusted by << 
589           execution. By using pipes or other t << 
590           to the process as file descriptors s << 
591           syscalls, it's possible to isolate t << 
592           own address space using seccomp. Onc << 
593           prctl(PR_SET_SECCOMP) or the seccomp << 
594           disabled and the task is only allowe << 
595           syscalls defined by each seccomp mod << 
596                                                << 
597           If unsure, say Y.                    << 
598                                                   449 
599 config SECCOMP_FILTER                             450 config SECCOMP_FILTER
600         def_bool y                                451         def_bool y
601         depends on HAVE_ARCH_SECCOMP_FILTER &&    452         depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
602         help                                      453         help
603           Enable tasks to build secure computi    454           Enable tasks to build secure computing environments defined
604           in terms of Berkeley Packet Filter p    455           in terms of Berkeley Packet Filter programs which implement
605           task-defined system call filtering p    456           task-defined system call filtering polices.
606                                                   457 
607           See Documentation/userspace-api/secc    458           See Documentation/userspace-api/seccomp_filter.rst for details.
608                                                   459 
609 config SECCOMP_CACHE_DEBUG                     << 
610         bool "Show seccomp filter cache status << 
611         depends on SECCOMP_FILTER && !HAVE_SPA << 
612         depends on PROC_FS                     << 
613         help                                   << 
614           This enables the /proc/pid/seccomp_c << 
615           seccomp cache data. The file format  << 
616           the file requires CAP_SYS_ADMIN.     << 
617                                                << 
618           This option is for debugging only. E << 
619           an adversary may be able to infer th << 
620                                                << 
621           If unsure, say N.                    << 
622                                                << 
623 config HAVE_ARCH_STACKLEAK                        460 config HAVE_ARCH_STACKLEAK
624         bool                                      461         bool
625         help                                      462         help
626           An architecture should select this i    463           An architecture should select this if it has the code which
627           fills the used part of the kernel st    464           fills the used part of the kernel stack with the STACKLEAK_POISON
628           value before returning from system c    465           value before returning from system calls.
629                                                   466 
630 config HAVE_STACKPROTECTOR                        467 config HAVE_STACKPROTECTOR
631         bool                                      468         bool
632         help                                      469         help
633           An arch should select this symbol if    470           An arch should select this symbol if:
634           - it has implemented a stack canary     471           - it has implemented a stack canary (e.g. __stack_chk_guard)
635                                                   472 
                                                   >> 473 config CC_HAS_STACKPROTECTOR_NONE
                                                   >> 474         def_bool $(cc-option,-fno-stack-protector)
                                                   >> 475 
636 config STACKPROTECTOR                             476 config STACKPROTECTOR
637         bool "Stack Protector buffer overflow     477         bool "Stack Protector buffer overflow detection"
638         depends on HAVE_STACKPROTECTOR            478         depends on HAVE_STACKPROTECTOR
639         depends on $(cc-option,-fstack-protect    479         depends on $(cc-option,-fstack-protector)
640         default y                                 480         default y
641         help                                      481         help
642           This option turns on the "stack-prot    482           This option turns on the "stack-protector" GCC feature. This
643           feature puts, at the beginning of fu    483           feature puts, at the beginning of functions, a canary value on
644           the stack just before the return add    484           the stack just before the return address, and validates
645           the value just before actually retur    485           the value just before actually returning.  Stack based buffer
646           overflows (that need to overwrite th    486           overflows (that need to overwrite this return address) now also
647           overwrite the canary, which gets det    487           overwrite the canary, which gets detected and the attack is then
648           neutralized via a kernel panic.         488           neutralized via a kernel panic.
649                                                   489 
650           Functions will have the stack-protec    490           Functions will have the stack-protector canary logic added if they
651           have an 8-byte or larger character a    491           have an 8-byte or larger character array on the stack.
652                                                   492 
653           This feature requires gcc version 4.    493           This feature requires gcc version 4.2 or above, or a distribution
654           gcc with the feature backported ("-f    494           gcc with the feature backported ("-fstack-protector").
655                                                   495 
656           On an x86 "defconfig" build, this fe    496           On an x86 "defconfig" build, this feature adds canary checks to
657           about 3% of all kernel functions, wh    497           about 3% of all kernel functions, which increases kernel code size
658           by about 0.3%.                          498           by about 0.3%.
659                                                   499 
660 config STACKPROTECTOR_STRONG                      500 config STACKPROTECTOR_STRONG
661         bool "Strong Stack Protector"             501         bool "Strong Stack Protector"
662         depends on STACKPROTECTOR                 502         depends on STACKPROTECTOR
663         depends on $(cc-option,-fstack-protect    503         depends on $(cc-option,-fstack-protector-strong)
664         default y                                 504         default y
665         help                                      505         help
666           Functions will have the stack-protec    506           Functions will have the stack-protector canary logic added in any
667           of the following conditions:            507           of the following conditions:
668                                                   508 
669           - local variable's address used as p    509           - local variable's address used as part of the right hand side of an
670             assignment or function argument       510             assignment or function argument
671           - local variable is an array (or uni    511           - local variable is an array (or union containing an array),
672             regardless of array type or length    512             regardless of array type or length
673           - uses register local variables         513           - uses register local variables
674                                                   514 
675           This feature requires gcc version 4.    515           This feature requires gcc version 4.9 or above, or a distribution
676           gcc with the feature backported ("-f    516           gcc with the feature backported ("-fstack-protector-strong").
677                                                   517 
678           On an x86 "defconfig" build, this fe    518           On an x86 "defconfig" build, this feature adds canary checks to
679           about 20% of all kernel functions, w    519           about 20% of all kernel functions, which increases the kernel code
680           size by about 2%.                       520           size by about 2%.
681                                                   521 
682 config ARCH_SUPPORTS_SHADOW_CALL_STACK         << 
683         bool                                   << 
684         help                                   << 
685           An architecture should select this i << 
686           Shadow Call Stack and implements run << 
687           switching.                           << 
688                                                << 
689 config SHADOW_CALL_STACK                       << 
690         bool "Shadow Call Stack"               << 
691         depends on ARCH_SUPPORTS_SHADOW_CALL_S << 
692         depends on DYNAMIC_FTRACE_WITH_ARGS || << 
693         depends on MMU                         << 
694         help                                   << 
695           This option enables the compiler's S << 
696           uses a shadow stack to protect funct << 
697           being overwritten by an attacker. Mo << 
698           in the compiler's documentation:     << 
699                                                << 
700           - Clang: https://clang.llvm.org/docs << 
701           - GCC: https://gcc.gnu.org/onlinedoc << 
702                                                << 
703           Note that security guarantees in the << 
704           ones documented for user space. The  << 
705           of shadow stacks in memory, which me << 
706           reading and writing arbitrary memory << 
707           and hijack control flow by modifying << 
708                                                << 
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                                     << 
717         bool                                   << 
718         help                                   << 
719           Selected if the kernel will be built << 
720                                                << 
721 config LTO_CLANG                               << 
722         bool                                   << 
723         select LTO                             << 
724         help                                   << 
725           Selected if the kernel will be built << 
726                                                << 
727 config ARCH_SUPPORTS_LTO_CLANG                 << 
728         bool                                   << 
729         help                                   << 
730           An architecture should select this o << 
731           - compiling with Clang,              << 
732           - compiling inline assembly with Cla << 
733           - and linking with LLD.              << 
734                                                << 
735 config ARCH_SUPPORTS_LTO_CLANG_THIN            << 
736         bool                                   << 
737         help                                   << 
738           An architecture should select this o << 
739           ThinLTO mode.                        << 
740                                                << 
741 config HAS_LTO_CLANG                           << 
742         def_bool y                             << 
743         depends on CC_IS_CLANG && LD_IS_LLD && << 
744         depends on $(success,$(NM) --help | he << 
745         depends on $(success,$(AR) --help | he << 
746         depends on ARCH_SUPPORTS_LTO_CLANG     << 
747         depends on !FTRACE_MCOUNT_USE_RECORDMC << 
748         # https://github.com/ClangBuiltLinux/l << 
749         depends on (!KASAN || KASAN_HW_TAGS || << 
750         depends on (!KCOV || CLANG_VERSION >=  << 
751         depends on !GCOV_KERNEL                << 
752         help                                   << 
753           The compiler and Kconfig options sup << 
754           LTO.                                 << 
755                                                << 
756 choice                                         << 
757         prompt "Link Time Optimization (LTO)"  << 
758         default LTO_NONE                       << 
759         help                                   << 
760           This option enables Link Time Optimi << 
761           compiler to optimize binaries global << 
762                                                << 
763           If unsure, select LTO_NONE. Note tha << 
764           so it's disabled by default.         << 
765                                                << 
766 config LTO_NONE                                << 
767         bool "None"                            << 
768         help                                   << 
769           Build the kernel normally, without L << 
770                                                << 
771 config LTO_CLANG_FULL                          << 
772         bool "Clang Full LTO (EXPERIMENTAL)"   << 
773         depends on HAS_LTO_CLANG               << 
774         depends on !COMPILE_TEST               << 
775         select LTO_CLANG                       << 
776         help                                   << 
777           This option enables Clang's full Lin << 
778           allows the compiler to optimize the  << 
779           this option, the compiler generates  << 
780           object files, and the actual compila << 
781           the LTO link step, which may take se << 
782           kernel configuration. More informati << 
783           documentation:                       << 
784                                                << 
785             https://llvm.org/docs/LinkTimeOpti << 
786                                                << 
787           During link time, this option can us << 
788           may take much longer than the ThinLT << 
789                                                << 
790 config LTO_CLANG_THIN                          << 
791         bool "Clang ThinLTO (EXPERIMENTAL)"    << 
792         depends on HAS_LTO_CLANG && ARCH_SUPPO << 
793         select LTO_CLANG                       << 
794         help                                   << 
795           This option enables Clang's ThinLTO, << 
796           optimization and faster incremental  << 
797           CONFIG_LTO_CLANG_FULL option. More i << 
798           from Clang's documentation:          << 
799                                                << 
800             https://clang.llvm.org/docs/ThinLT << 
801                                                << 
802           If unsure, say Y.                    << 
803 endchoice                                      << 
804                                                << 
805 config ARCH_SUPPORTS_CFI_CLANG                 << 
806         bool                                   << 
807         help                                   << 
808           An architecture should select this o << 
809           Control-Flow Integrity (CFI) checkin << 
810                                                << 
811 config ARCH_USES_CFI_TRAPS                     << 
812         bool                                   << 
813                                                << 
814 config CFI_CLANG                               << 
815         bool "Use Clang's Control Flow Integri << 
816         depends on ARCH_SUPPORTS_CFI_CLANG     << 
817         depends on $(cc-option,-fsanitize=kcfi << 
818         help                                   << 
819           This option enables Clang's forward- << 
820           (CFI) checking, where the compiler i << 
821           indirect function call to ensure the << 
822           the correct static type. This restri << 
823           makes it more difficult for an attac << 
824           the modification of stored function  << 
825           found from Clang's documentation:    << 
826                                                << 
827             https://clang.llvm.org/docs/Contro << 
828                                                << 
829 config CFI_PERMISSIVE                          << 
830         bool "Use CFI in permissive mode"      << 
831         depends on CFI_CLANG                   << 
832         help                                   << 
833           When selected, Control Flow Integrit << 
834           warning instead of a kernel panic. T << 
835           for finding indirect call type misma << 
836                                                << 
837           If unsure, say N.                    << 
838                                                << 
839 config HAVE_ARCH_WITHIN_STACK_FRAMES              522 config HAVE_ARCH_WITHIN_STACK_FRAMES
840         bool                                      523         bool
841         help                                      524         help
842           An architecture should select this i    525           An architecture should select this if it can walk the kernel stack
843           frames to determine if an object is     526           frames to determine if an object is part of either the arguments
844           or local variables (i.e. that it exc    527           or local variables (i.e. that it excludes saved return addresses,
845           and similar) by implementing an inli    528           and similar) by implementing an inline arch_within_stack_frames(),
846           which is used by CONFIG_HARDENED_USE    529           which is used by CONFIG_HARDENED_USERCOPY.
847                                                   530 
848 config HAVE_CONTEXT_TRACKING_USER              !! 531 config HAVE_CONTEXT_TRACKING
849         bool                                      532         bool
850         help                                      533         help
851           Provide kernel/user boundaries probe    534           Provide kernel/user boundaries probes necessary for subsystems
852           that need it, such as userspace RCU     535           that need it, such as userspace RCU extended quiescent state.
853           Syscalls need to be wrapped inside u !! 536           Syscalls need to be wrapped inside user_exit()-user_enter() through
854           optimized behind static key or throu !! 537           the slow path using TIF_NOHZ flag. Exceptions handlers must be
855           flag. Exceptions handlers must be wr !! 538           wrapped as well. Irqs are already protected inside
856           protected inside ct_irq_enter/ct_irq !! 539           rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on
857           handling on irq exit still need to b !! 540           irq exit still need to be protected.
858                                                << 
859 config HAVE_CONTEXT_TRACKING_USER_OFFSTACK     << 
860         bool                                   << 
861         help                                   << 
862           Architecture neither relies on excep << 
863           nor on schedule_user(). Also preempt << 
864           preempt_schedule_irq() can't be call << 
865           while context tracking is CONTEXT_US << 
866           entry implementation where the follo << 
867           critical entry code, ie: before user << 
868                                                << 
869           - Critical entry code isn't preempti << 
870             not interruptible).                << 
871           - No use of RCU read side critical s << 
872             got called.                        << 
873           - No use of instrumentation, unless  << 
874             called.                            << 
875                                                << 
876 config HAVE_TIF_NOHZ                           << 
877         bool                                   << 
878         help                                   << 
879           Arch relies on TIF_NOHZ and syscall  << 
880           tracking calls to user_enter()/user_ << 
881                                                   541 
882 config HAVE_VIRT_CPU_ACCOUNTING                   542 config HAVE_VIRT_CPU_ACCOUNTING
883         bool                                      543         bool
884                                                   544 
885 config HAVE_VIRT_CPU_ACCOUNTING_IDLE           << 
886         bool                                   << 
887         help                                   << 
888           Architecture has its own way to acco << 
889           doesn't implement vtime_account_idle << 
890                                                << 
891 config ARCH_HAS_SCALED_CPUTIME                    545 config ARCH_HAS_SCALED_CPUTIME
892         bool                                      546         bool
893                                                   547 
894 config HAVE_VIRT_CPU_ACCOUNTING_GEN               548 config HAVE_VIRT_CPU_ACCOUNTING_GEN
895         bool                                      549         bool
896         default y if 64BIT                        550         default y if 64BIT
897         help                                      551         help
898           With VIRT_CPU_ACCOUNTING_GEN, cputim    552           With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
899           Before enabling this option, arch co    553           Before enabling this option, arch code must be audited
900           to ensure there are no races in conc    554           to ensure there are no races in concurrent read/write of
901           cputime_t. For example, reading/writ    555           cputime_t. For example, reading/writing 64-bit cputime_t on
902           some 32-bit arches may require multi    556           some 32-bit arches may require multiple accesses, so proper
903           locking is needed to protect against    557           locking is needed to protect against concurrent accesses.
904                                                   558 
                                                   >> 559 
905 config HAVE_IRQ_TIME_ACCOUNTING                   560 config HAVE_IRQ_TIME_ACCOUNTING
906         bool                                      561         bool
907         help                                      562         help
908           Archs need to ensure they use a high    563           Archs need to ensure they use a high enough resolution clock to
909           support irq time accounting and then    564           support irq time accounting and then call enable_sched_clock_irqtime().
910                                                   565 
911 config HAVE_MOVE_PUD                           << 
912         bool                                   << 
913         help                                   << 
914           Architectures that select this are a << 
915           PUD level. If there are only 3 page  << 
916           happens at the PGD level.            << 
917                                                << 
918 config HAVE_MOVE_PMD                              566 config HAVE_MOVE_PMD
919         bool                                      567         bool
920         help                                      568         help
921           Archs that select this are able to m    569           Archs that select this are able to move page tables at the PMD level.
922                                                   570 
923 config HAVE_ARCH_TRANSPARENT_HUGEPAGE             571 config HAVE_ARCH_TRANSPARENT_HUGEPAGE
924         bool                                      572         bool
925                                                   573 
926 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD         574 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
927         bool                                      575         bool
928                                                   576 
929 config HAVE_ARCH_HUGE_VMAP                        577 config HAVE_ARCH_HUGE_VMAP
930         bool                                      578         bool
931                                                   579 
932 #                                              << 
933 #  Archs that select this would be capable of  << 
934 #  arch_vmap_pmd_supported() returns true). Th << 
935 #  must be used to enable allocations to use h << 
936 #                                              << 
937 config HAVE_ARCH_HUGE_VMALLOC                  << 
938         depends on HAVE_ARCH_HUGE_VMAP         << 
939         bool                                   << 
940                                                << 
941 config ARCH_WANT_HUGE_PMD_SHARE                << 
942         bool                                   << 
943                                                << 
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                       580 config HAVE_ARCH_SOFT_DIRTY
953         bool                                      581         bool
954                                                   582 
955 config HAVE_MOD_ARCH_SPECIFIC                     583 config HAVE_MOD_ARCH_SPECIFIC
956         bool                                      584         bool
957         help                                      585         help
958           The arch uses struct mod_arch_specif    586           The arch uses struct mod_arch_specific to store data.  Many arches
959           just need a simple module loader wit    587           just need a simple module loader without arch specific data - those
960           should not enable this.                 588           should not enable this.
961                                                   589 
962 config MODULES_USE_ELF_RELA                       590 config MODULES_USE_ELF_RELA
963         bool                                      591         bool
964         help                                      592         help
965           Modules only use ELF RELA relocation    593           Modules only use ELF RELA relocations.  Modules with ELF REL
966           relocations will give an error.         594           relocations will give an error.
967                                                   595 
968 config MODULES_USE_ELF_REL                        596 config MODULES_USE_ELF_REL
969         bool                                      597         bool
970         help                                      598         help
971           Modules only use ELF REL relocations    599           Modules only use ELF REL relocations.  Modules with ELF RELA
972           relocations will give an error.         600           relocations will give an error.
973                                                   601 
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                 602 config HAVE_IRQ_EXIT_ON_IRQ_STACK
989         bool                                      603         bool
990         help                                      604         help
991           Architecture doesn't only execute th    605           Architecture doesn't only execute the irq handler on the irq stack
992           but also irq_exit(). This way we can    606           but also irq_exit(). This way we can process softirqs on this irq
993           stack instead of switching to a new     607           stack instead of switching to a new one when we call __do_softirq()
994           in the end of an hardirq.               608           in the end of an hardirq.
995           This spares a stack switch and impro    609           This spares a stack switch and improves cache usage on softirq
996           processing.                             610           processing.
997                                                   611 
998 config HAVE_SOFTIRQ_ON_OWN_STACK               << 
999         bool                                   << 
1000         help                                  << 
1001           Architecture provides a function to << 
1002           separate stack.                     << 
1003                                               << 
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                            612 config PGTABLE_LEVELS
1015         int                                      613         int
1016         default 2                                614         default 2
1017                                                  615 
1018 config ARCH_HAS_ELF_RANDOMIZE                    616 config ARCH_HAS_ELF_RANDOMIZE
1019         bool                                     617         bool
1020         help                                     618         help
1021           An architecture supports choosing r    619           An architecture supports choosing randomized locations for
1022           stack, mmap, brk, and ET_DYN. Defin    620           stack, mmap, brk, and ET_DYN. Defined functions:
1023           - arch_mmap_rnd()                      621           - arch_mmap_rnd()
1024           - arch_randomize_brk()                 622           - arch_randomize_brk()
1025                                                  623 
1026 config HAVE_ARCH_MMAP_RND_BITS                   624 config HAVE_ARCH_MMAP_RND_BITS
1027         bool                                     625         bool
1028         help                                     626         help
1029           An arch should select this symbol i    627           An arch should select this symbol if it supports setting a variable
1030           number of bits for use in establish    628           number of bits for use in establishing the base address for mmap
1031           allocations, has MMU enabled and pr    629           allocations, has MMU enabled and provides values for both:
1032           - ARCH_MMAP_RND_BITS_MIN               630           - ARCH_MMAP_RND_BITS_MIN
1033           - ARCH_MMAP_RND_BITS_MAX               631           - ARCH_MMAP_RND_BITS_MAX
1034                                                  632 
1035 config HAVE_EXIT_THREAD                          633 config HAVE_EXIT_THREAD
1036         bool                                     634         bool
1037         help                                     635         help
1038           An architecture implements exit_thr    636           An architecture implements exit_thread.
1039                                                  637 
1040 config ARCH_MMAP_RND_BITS_MIN                    638 config ARCH_MMAP_RND_BITS_MIN
1041         int                                      639         int
1042                                                  640 
1043 config ARCH_MMAP_RND_BITS_MAX                    641 config ARCH_MMAP_RND_BITS_MAX
1044         int                                      642         int
1045                                                  643 
1046 config ARCH_MMAP_RND_BITS_DEFAULT                644 config ARCH_MMAP_RND_BITS_DEFAULT
1047         int                                      645         int
1048                                                  646 
1049 config ARCH_MMAP_RND_BITS                        647 config ARCH_MMAP_RND_BITS
1050         int "Number of bits to use for ASLR o    648         int "Number of bits to use for ASLR of mmap base address" if EXPERT
1051         range ARCH_MMAP_RND_BITS_MIN ARCH_MMA    649         range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
1052         default ARCH_MMAP_RND_BITS_DEFAULT if    650         default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
1053         default ARCH_MMAP_RND_BITS_MIN           651         default ARCH_MMAP_RND_BITS_MIN
1054         depends on HAVE_ARCH_MMAP_RND_BITS       652         depends on HAVE_ARCH_MMAP_RND_BITS
1055         help                                     653         help
1056           This value can be used to select th    654           This value can be used to select the number of bits to use to
1057           determine the random offset to the     655           determine the random offset to the base address of vma regions
1058           resulting from mmap allocations. Th    656           resulting from mmap allocations. This value will be bounded
1059           by the architecture's minimum and m    657           by the architecture's minimum and maximum supported values.
1060                                                  658 
1061           This value can be changed after boo    659           This value can be changed after boot using the
1062           /proc/sys/vm/mmap_rnd_bits tunable     660           /proc/sys/vm/mmap_rnd_bits tunable
1063                                                  661 
1064 config HAVE_ARCH_MMAP_RND_COMPAT_BITS            662 config HAVE_ARCH_MMAP_RND_COMPAT_BITS
1065         bool                                     663         bool
1066         help                                     664         help
1067           An arch should select this symbol i    665           An arch should select this symbol if it supports running applications
1068           in compatibility mode, supports set    666           in compatibility mode, supports setting a variable number of bits for
1069           use in establishing the base addres    667           use in establishing the base address for mmap allocations, has MMU
1070           enabled and provides values for bot    668           enabled and provides values for both:
1071           - ARCH_MMAP_RND_COMPAT_BITS_MIN        669           - ARCH_MMAP_RND_COMPAT_BITS_MIN
1072           - ARCH_MMAP_RND_COMPAT_BITS_MAX        670           - ARCH_MMAP_RND_COMPAT_BITS_MAX
1073                                                  671 
1074 config ARCH_MMAP_RND_COMPAT_BITS_MIN             672 config ARCH_MMAP_RND_COMPAT_BITS_MIN
1075         int                                      673         int
1076                                                  674 
1077 config ARCH_MMAP_RND_COMPAT_BITS_MAX             675 config ARCH_MMAP_RND_COMPAT_BITS_MAX
1078         int                                      676         int
1079                                                  677 
1080 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT         678 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1081         int                                      679         int
1082                                                  680 
1083 config ARCH_MMAP_RND_COMPAT_BITS                 681 config ARCH_MMAP_RND_COMPAT_BITS
1084         int "Number of bits to use for ASLR o    682         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    683         range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
1086         default ARCH_MMAP_RND_COMPAT_BITS_DEF    684         default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1087         default ARCH_MMAP_RND_COMPAT_BITS_MIN    685         default ARCH_MMAP_RND_COMPAT_BITS_MIN
1088         depends on HAVE_ARCH_MMAP_RND_COMPAT_    686         depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
1089         help                                     687         help
1090           This value can be used to select th    688           This value can be used to select the number of bits to use to
1091           determine the random offset to the     689           determine the random offset to the base address of vma regions
1092           resulting from mmap allocations for    690           resulting from mmap allocations for compatible applications This
1093           value will be bounded by the archit    691           value will be bounded by the architecture's minimum and maximum
1094           supported values.                      692           supported values.
1095                                                  693 
1096           This value can be changed after boo    694           This value can be changed after boot using the
1097           /proc/sys/vm/mmap_rnd_compat_bits t    695           /proc/sys/vm/mmap_rnd_compat_bits tunable
1098                                                  696 
1099 config HAVE_ARCH_COMPAT_MMAP_BASES               697 config HAVE_ARCH_COMPAT_MMAP_BASES
1100         bool                                     698         bool
1101         help                                     699         help
1102           This allows 64bit applications to i    700           This allows 64bit applications to invoke 32-bit mmap() syscall
1103           and vice-versa 32-bit applications     701           and vice-versa 32-bit applications to call 64-bit mmap().
1104           Required for applications doing dif    702           Required for applications doing different bitness syscalls.
1105                                                  703 
1106 config HAVE_PAGE_SIZE_4KB                     !! 704 config HAVE_COPY_THREAD_TLS
1107         bool                                  << 
1108                                               << 
1109 config HAVE_PAGE_SIZE_8KB                     << 
1110         bool                                     705         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                                     706         help
1149           This option is usually a good compr !! 707           Architecture provides copy_thread_tls to accept tls argument via
1150           consumption and performance for typ !! 708           normal C parameter passing, rather than extracting the syscall
1151           workloads, often saving a level of  !! 709           argument from pt_regs.
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               << 
1190         def_bool y                            << 
1191         depends on !PAGE_SIZE_64KB            << 
1192         depends on PAGE_SIZE_LESS_THAN_256KB  << 
1193                                               << 
1194 config PAGE_SIZE_LESS_THAN_256KB              << 
1195         def_bool y                            << 
1196         depends on !PAGE_SIZE_256KB           << 
1197                                               << 
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 << 
1208 # address by giving priority to top-down sche << 
1209 # is not in legacy mode (compat task, unlimit << 
1210 # sysctl_legacy_va_layout).                   << 
1211 # Architecture that selects this option can p << 
1212 # - STACK_RND_MASK                            << 
1213 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT  << 
1214         bool                                  << 
1215         depends on MMU                        << 
1216         select ARCH_HAS_ELF_RANDOMIZE         << 
1217                                               << 
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                                                  710 
1234 config HAVE_STACK_VALIDATION                     711 config HAVE_STACK_VALIDATION
1235         bool                                     712         bool
1236         help                                     713         help
1237           Architecture supports objtool compi !! 714           Architecture supports the 'objtool check' host tool command, which
1238           validation.                         !! 715           performs compile-time stack metadata validation.
1239                                                  716 
1240 config HAVE_RELIABLE_STACKTRACE                  717 config HAVE_RELIABLE_STACKTRACE
1241         bool                                     718         bool
1242         help                                     719         help
1243           Architecture has either save_stack_ !! 720           Architecture has a save_stack_trace_tsk_reliable() function which
1244           arch_stack_walk_reliable() function !! 721           only returns a stack trace if it can guarantee the trace is reliable.
1245           if it can guarantee the trace is re << 
1246                                                  722 
1247 config HAVE_ARCH_HASH                            723 config HAVE_ARCH_HASH
1248         bool                                     724         bool
1249         default n                                725         default n
1250         help                                     726         help
1251           If this is set, the architecture pr    727           If this is set, the architecture provides an <asm/hash.h>
1252           file which provides platform-specif    728           file which provides platform-specific implementations of some
1253           functions in <linux/hash.h> or fs/n    729           functions in <linux/hash.h> or fs/namei.c.
1254                                                  730 
1255 config HAVE_ARCH_NVRAM_OPS                       731 config HAVE_ARCH_NVRAM_OPS
1256         bool                                     732         bool
1257                                                  733 
1258 config ISA_BUS_API                               734 config ISA_BUS_API
1259         def_bool ISA                             735         def_bool ISA
1260                                                  736 
1261 #                                                737 #
1262 # ABI hall of shame                              738 # ABI hall of shame
1263 #                                                739 #
1264 config CLONE_BACKWARDS                           740 config CLONE_BACKWARDS
1265         bool                                     741         bool
1266         help                                     742         help
1267           Architecture has tls passed as the     743           Architecture has tls passed as the 4th argument of clone(2),
1268           not the 5th one.                       744           not the 5th one.
1269                                                  745 
1270 config CLONE_BACKWARDS2                          746 config CLONE_BACKWARDS2
1271         bool                                     747         bool
1272         help                                     748         help
1273           Architecture has the first two argu    749           Architecture has the first two arguments of clone(2) swapped.
1274                                                  750 
1275 config CLONE_BACKWARDS3                          751 config CLONE_BACKWARDS3
1276         bool                                     752         bool
1277         help                                     753         help
1278           Architecture has tls passed as the     754           Architecture has tls passed as the 3rd argument of clone(2),
1279           not the 5th one.                       755           not the 5th one.
1280                                                  756 
1281 config ODD_RT_SIGACTION                          757 config ODD_RT_SIGACTION
1282         bool                                     758         bool
1283         help                                     759         help
1284           Architecture has unusual rt_sigacti    760           Architecture has unusual rt_sigaction(2) arguments
1285                                                  761 
1286 config OLD_SIGSUSPEND                            762 config OLD_SIGSUSPEND
1287         bool                                     763         bool
1288         help                                     764         help
1289           Architecture has old sigsuspend(2)     765           Architecture has old sigsuspend(2) syscall, of one-argument variety
1290                                                  766 
1291 config OLD_SIGSUSPEND3                           767 config OLD_SIGSUSPEND3
1292         bool                                     768         bool
1293         help                                     769         help
1294           Even weirder antique ABI - three-ar    770           Even weirder antique ABI - three-argument sigsuspend(2)
1295                                                  771 
1296 config OLD_SIGACTION                             772 config OLD_SIGACTION
1297         bool                                     773         bool
1298         help                                     774         help
1299           Architecture has old sigaction(2) s    775           Architecture has old sigaction(2) syscall.  Nope, not the same
1300           as OLD_SIGSUSPEND | OLD_SIGSUSPEND3    776           as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
1301           but fairly different variant of sig    777           but fairly different variant of sigaction(2), thanks to OSF/1
1302           compatibility...                       778           compatibility...
1303                                                  779 
1304 config COMPAT_OLD_SIGACTION                      780 config COMPAT_OLD_SIGACTION
1305         bool                                     781         bool
1306                                                  782 
                                                   >> 783 config 64BIT_TIME
                                                   >> 784         def_bool y
                                                   >> 785         help
                                                   >> 786           This should be selected by all architectures that need to support
                                                   >> 787           new system calls with a 64-bit time_t. This is relevant on all 32-bit
                                                   >> 788           architectures, and 64-bit architectures as part of compat syscall
                                                   >> 789           handling.
                                                   >> 790 
1307 config COMPAT_32BIT_TIME                         791 config COMPAT_32BIT_TIME
1308         bool "Provide system calls for 32-bit !! 792         def_bool !64BIT || COMPAT
1309         default !64BIT || COMPAT              << 
1310         help                                     793         help
1311           This enables 32 bit time_t support     794           This enables 32 bit time_t support in addition to 64 bit time_t support.
1312           This is relevant on all 32-bit arch    795           This is relevant on all 32-bit architectures, and 64-bit architectures
1313           as part of compat syscall handling.    796           as part of compat syscall handling.
1314                                                  797 
1315 config ARCH_NO_PREEMPT                        !! 798 config ARCH_NO_COHERENT_DMA_MMAP
1316         bool                                     799         bool
1317                                                  800 
1318 config ARCH_SUPPORTS_RT                       !! 801 config ARCH_NO_PREEMPT
1319         bool                                     802         bool
1320                                                  803 
1321 config CPU_NO_EFFICIENT_FFS                      804 config CPU_NO_EFFICIENT_FFS
1322         def_bool n                               805         def_bool n
1323                                                  806 
1324 config HAVE_ARCH_VMAP_STACK                      807 config HAVE_ARCH_VMAP_STACK
1325         def_bool n                               808         def_bool n
1326         help                                     809         help
1327           An arch should select this symbol i    810           An arch should select this symbol if it can support kernel stacks
1328           in vmalloc space.  This means:         811           in vmalloc space.  This means:
1329                                                  812 
1330           - vmalloc space must be large enoug    813           - vmalloc space must be large enough to hold many kernel stacks.
1331             This may rule out many 32-bit arc    814             This may rule out many 32-bit architectures.
1332                                                  815 
1333           - Stacks in vmalloc space need to w    816           - Stacks in vmalloc space need to work reliably.  For example, if
1334             vmap page tables are created on d    817             vmap page tables are created on demand, either this mechanism
1335             needs to work while the stack poi    818             needs to work while the stack points to a virtual address with
1336             unpopulated page tables or arch c    819             unpopulated page tables or arch code (switch_to() and switch_mm(),
1337             most likely) needs to ensure that    820             most likely) needs to ensure that the stack's page table entries
1338             are populated before running on a    821             are populated before running on a possibly unpopulated stack.
1339                                                  822 
1340           - If the stack overflows into a gua    823           - If the stack overflows into a guard page, something reasonable
1341             should happen.  The definition of    824             should happen.  The definition of "reasonable" is flexible, but
1342             instantly rebooting without loggi    825             instantly rebooting without logging anything would be unfriendly.
1343                                                  826 
1344 config VMAP_STACK                                827 config VMAP_STACK
1345         default y                                828         default y
1346         bool "Use a virtually-mapped stack"      829         bool "Use a virtually-mapped stack"
1347         depends on HAVE_ARCH_VMAP_STACK       !! 830         depends on HAVE_ARCH_VMAP_STACK && !KASAN
1348         depends on !KASAN || KASAN_HW_TAGS || !! 831         ---help---
1349         help                                  << 
1350           Enable this if you want the use vir    832           Enable this if you want the use virtually-mapped kernel stacks
1351           with guard pages.  This causes kern    833           with guard pages.  This causes kernel stack overflows to be
1352           caught immediately rather than caus    834           caught immediately rather than causing difficult-to-diagnose
1353           corruption.                            835           corruption.
1354                                                  836 
1355           To use this with software KASAN mod !! 837           This is presently incompatible with KASAN because KASAN expects
1356           backing virtual mappings with real  !! 838           the stack to map directly to the KASAN shadow map using a formula
1357           must be enabled.                    !! 839           that is incorrect if the stack is in vmalloc space.
1358                                               << 
1359 config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET      << 
1360         def_bool n                            << 
1361         help                                  << 
1362           An arch should select this symbol i << 
1363           offset randomization with calls to  << 
1364           during syscall entry and choose_ran << 
1365           syscall exit. Careful removal of -f << 
1366           -fstack-protector should also be ap << 
1367           closely examined, as the artificial << 
1368           to the compiler, so it will attempt << 
1369           of the static branch state.         << 
1370                                               << 
1371 config RANDOMIZE_KSTACK_OFFSET                << 
1372         bool "Support for randomizing kernel  << 
1373         default y                             << 
1374         depends on HAVE_ARCH_RANDOMIZE_KSTACK << 
1375         depends on INIT_STACK_NONE || !CC_IS_ << 
1376         help                                  << 
1377           The kernel stack offset can be rand << 
1378           roughly 5 bits of entropy, frustrat << 
1379           attacks that depend on stack addres << 
1380           cross-syscall address exposures.    << 
1381                                               << 
1382           The feature is controlled via the " << 
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                                                  840 
1396 config ARCH_OPTIONAL_KERNEL_RWX                  841 config ARCH_OPTIONAL_KERNEL_RWX
1397         def_bool n                               842         def_bool n
1398                                                  843 
1399 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT          844 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1400         def_bool n                               845         def_bool n
1401                                                  846 
1402 config ARCH_HAS_STRICT_KERNEL_RWX                847 config ARCH_HAS_STRICT_KERNEL_RWX
1403         def_bool n                               848         def_bool n
1404                                                  849 
1405 config STRICT_KERNEL_RWX                         850 config STRICT_KERNEL_RWX
1406         bool "Make kernel text and rodata rea    851         bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
1407         depends on ARCH_HAS_STRICT_KERNEL_RWX    852         depends on ARCH_HAS_STRICT_KERNEL_RWX
1408         default !ARCH_OPTIONAL_KERNEL_RWX ||     853         default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1409         help                                     854         help
1410           If this is set, kernel text and rod    855           If this is set, kernel text and rodata memory will be made read-only,
1411           and non-text memory will be made no    856           and non-text memory will be made non-executable. This provides
1412           protection against certain security    857           protection against certain security exploits (e.g. executing the heap
1413           or modifying text)                     858           or modifying text)
1414                                                  859 
1415           These features are considered stand    860           These features are considered standard security practice these days.
1416           You should say Y here in almost all    861           You should say Y here in almost all cases.
1417                                                  862 
1418 config ARCH_HAS_STRICT_MODULE_RWX                863 config ARCH_HAS_STRICT_MODULE_RWX
1419         def_bool n                               864         def_bool n
1420                                                  865 
1421 config STRICT_MODULE_RWX                         866 config STRICT_MODULE_RWX
1422         bool "Set loadable kernel module data    867         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    868         depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES
1424         default !ARCH_OPTIONAL_KERNEL_RWX ||     869         default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1425         help                                     870         help
1426           If this is set, module text and rod    871           If this is set, module text and rodata memory will be made read-only,
1427           and non-text memory will be made no    872           and non-text memory will be made non-executable. This provides
1428           protection against certain security    873           protection against certain security exploits (e.g. writing to text)
1429                                                  874 
1430 # select if the architecture provides an asm/    875 # select if the architecture provides an asm/dma-direct.h header
1431 config ARCH_HAS_PHYS_TO_DMA                      876 config ARCH_HAS_PHYS_TO_DMA
1432         bool                                     877         bool
1433                                                  878 
                                                   >> 879 config ARCH_HAS_REFCOUNT
                                                   >> 880         bool
                                                   >> 881         help
                                                   >> 882           An architecture selects this when it has implemented refcount_t
                                                   >> 883           using open coded assembly primitives that provide an optimized
                                                   >> 884           refcount_t implementation, possibly at the expense of some full
                                                   >> 885           refcount state checks of CONFIG_REFCOUNT_FULL=y.
                                                   >> 886 
                                                   >> 887           The refcount overflow check behavior, however, must be retained.
                                                   >> 888           Catching overflows is the primary security concern for protecting
                                                   >> 889           against bugs in reference counts.
                                                   >> 890 
                                                   >> 891 config REFCOUNT_FULL
                                                   >> 892         bool "Perform full reference count validation at the expense of speed"
                                                   >> 893         help
                                                   >> 894           Enabling this switches the refcounting infrastructure from a fast
                                                   >> 895           unchecked atomic_t implementation to a fully state checked
                                                   >> 896           implementation, which can be (slightly) slower but provides protections
                                                   >> 897           against various use-after-free conditions that can be used in
                                                   >> 898           security flaw exploits.
                                                   >> 899 
1434 config HAVE_ARCH_COMPILER_H                      900 config HAVE_ARCH_COMPILER_H
1435         bool                                     901         bool
1436         help                                     902         help
1437           An architecture can select this if     903           An architecture can select this if it provides an
1438           asm/compiler.h header that should b    904           asm/compiler.h header that should be included after
1439           linux/compiler-*.h in order to over    905           linux/compiler-*.h in order to override macro definitions that those
1440           headers generally provide.             906           headers generally provide.
1441                                                  907 
1442 config HAVE_ARCH_PREL32_RELOCATIONS              908 config HAVE_ARCH_PREL32_RELOCATIONS
1443         bool                                     909         bool
1444         help                                     910         help
1445           May be selected by an architecture     911           May be selected by an architecture if it supports place-relative
1446           32-bit relocations, both in the too    912           32-bit relocations, both in the toolchain and in the module loader,
1447           in which case relative references c    913           in which case relative references can be used in special sections
1448           for PCI fixup, initcalls etc which     914           for PCI fixup, initcalls etc which are only half the size on 64 bit
1449           architectures, and don't require ru    915           architectures, and don't require runtime relocation on relocatable
1450           kernels.                               916           kernels.
1451                                                  917 
1452 config ARCH_USE_MEMREMAP_PROT                    918 config ARCH_USE_MEMREMAP_PROT
1453         bool                                     919         bool
1454                                                  920 
1455 config LOCK_EVENT_COUNTS                         921 config LOCK_EVENT_COUNTS
1456         bool "Locking event counts collection    922         bool "Locking event counts collection"
1457         depends on DEBUG_FS                      923         depends on DEBUG_FS
1458         help                                  !! 924         ---help---
1459           Enable light-weight counting of var    925           Enable light-weight counting of various locking related events
1460           in the system with minimal performa    926           in the system with minimal performance impact. This reduces
1461           the chance of application behavior     927           the chance of application behavior change because of timing
1462           differences. The counts are reporte    928           differences. The counts are reported via debugfs.
1463                                                  929 
1464 # Select if the architecture has support for  << 
1465 config ARCH_HAS_RELR                          << 
1466         bool                                  << 
1467                                               << 
1468 config RELR                                   << 
1469         bool "Use RELR relocation packing"    << 
1470         depends on ARCH_HAS_RELR && TOOLS_SUP << 
1471         default y                             << 
1472         help                                  << 
1473           Store the kernel's dynamic relocati << 
1474           format. Requires a compatible linke << 
1475           well as compatible NM and OBJCOPY u << 
1476           are compatible).                    << 
1477                                               << 
1478 config ARCH_HAS_MEM_ENCRYPT                   << 
1479         bool                                  << 
1480                                               << 
1481 config ARCH_HAS_CC_PLATFORM                   << 
1482         bool                                  << 
1483                                               << 
1484 config HAVE_SPARSE_SYSCALL_NR                 << 
1485         bool                                  << 
1486         help                                  << 
1487           An architecture should select this  << 
1488           to save space. For example, MIPS ar << 
1489           entries at 4000, 5000 and 6000 loca << 
1490           related optimizations for a given a << 
1491                                               << 
1492 config ARCH_HAS_VDSO_DATA                     << 
1493         bool                                  << 
1494                                               << 
1495 config HAVE_STATIC_CALL                       << 
1496         bool                                  << 
1497                                               << 
1498 config HAVE_STATIC_CALL_INLINE                << 
1499         bool                                  << 
1500         depends on HAVE_STATIC_CALL           << 
1501         select OBJTOOL                        << 
1502                                               << 
1503 config HAVE_PREEMPT_DYNAMIC                   << 
1504         bool                                  << 
1505                                               << 
1506 config HAVE_PREEMPT_DYNAMIC_CALL              << 
1507         bool                                  << 
1508         depends on HAVE_STATIC_CALL           << 
1509         select HAVE_PREEMPT_DYNAMIC           << 
1510         help                                  << 
1511           An architecture should select this  << 
1512           model being selected at boot time u << 
1513                                               << 
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                                               << 
1541 config ARCH_WANT_LD_ORPHAN_WARN               << 
1542         bool                                  << 
1543         help                                  << 
1544           An arch should select this symbol o << 
1545           included, size-asserted, or discard << 
1546           important because we never want exp << 
1547           by the linker, since the locations  << 
1548           versions.                           << 
1549                                               << 
1550 config HAVE_ARCH_PFN_VALID                    << 
1551         bool                                  << 
1552                                               << 
1553 config ARCH_SUPPORTS_DEBUG_PAGEALLOC          << 
1554         bool                                  << 
1555                                               << 
1556 config ARCH_SUPPORTS_PAGE_TABLE_CHECK         << 
1557         bool                                  << 
1558                                               << 
1559 config ARCH_SPLIT_ARG64                       << 
1560         bool                                  << 
1561         help                                  << 
1562           If a 32-bit architecture requires 6 << 
1563           pairs of 32-bit arguments, select t << 
1564                                               << 
1565 config ARCH_HAS_ELFCORE_COMPAT                << 
1566         bool                                  << 
1567                                               << 
1568 config ARCH_HAS_PARANOID_L1D_FLUSH            << 
1569         bool                                  << 
1570                                               << 
1571 config ARCH_HAVE_TRACE_MMIO_ACCESS            << 
1572         bool                                  << 
1573                                               << 
1574 config DYNAMIC_SIGFRAME                       << 
1575         bool                                  << 
1576                                               << 
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"                     930 source "kernel/gcov/Kconfig"
1604                                                  931 
1605 source "scripts/gcc-plugins/Kconfig"             932 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                                                  933 
1646 endmenu                                          934 endmenu
                                                      

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