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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-4.10.17)


  1 # SPDX-License-Identifier: GPL-2.0             << 
  2 #                                                   1 #
  3 # General architecture dependent options            2 # General architecture dependent options
  4 #                                                   3 #
  5                                                     4 
  6 #                                              !!   5 config KEXEC_CORE
  7 # Note: arch/$(SRCARCH)/Kconfig needs to be in << 
  8 # override the default values in this file.    << 
  9 #                                              << 
 10 source "arch/$(SRCARCH)/Kconfig"               << 
 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"  << 
 21                                                << 
 22 config ARCH_HAS_SUBPAGE_FAULTS                 << 
 23         bool                                   << 
 24         help                                   << 
 25           Select if the architecture can check << 
 26           granularity (e.g. arm64 MTE). The pr << 
 27           must be implemented.                 << 
 28                                                << 
 29 config HOTPLUG_SMT                             << 
 30         bool                                        6         bool
 31                                                     7 
 32 config SMT_NUM_THREADS_DYNAMIC                 !!   8 config HAVE_IMA_KEXEC
 33         bool                                        9         bool
 34                                                    10 
 35 # Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLU !!  11 config OPROFILE
 36 config HOTPLUG_CORE_SYNC                       !!  12         tristate "OProfile system profiling"
 37         bool                                   !!  13         depends on PROFILING
                                                   >>  14         depends on HAVE_OPROFILE
                                                   >>  15         select RING_BUFFER
                                                   >>  16         select RING_BUFFER_ALLOW_SWAP
                                                   >>  17         help
                                                   >>  18           OProfile is a profiling system capable of profiling the
                                                   >>  19           whole system, include the kernel, kernel modules, libraries,
                                                   >>  20           and applications.
 38                                                    21 
 39 # Basic CPU dead synchronization selected by a !!  22           If unsure, say N.
 40 config HOTPLUG_CORE_SYNC_DEAD                  << 
 41         bool                                   << 
 42         select HOTPLUG_CORE_SYNC               << 
 43                                                    23 
 44 # Full CPU synchronization with alive state se !!  24 config OPROFILE_EVENT_MULTIPLEX
 45 config HOTPLUG_CORE_SYNC_FULL                  !!  25         bool "OProfile multiplexing support (EXPERIMENTAL)"
 46         bool                                   !!  26         default n
 47         select HOTPLUG_CORE_SYNC_DEAD if HOTPL !!  27         depends on OPROFILE && X86
 48         select HOTPLUG_CORE_SYNC               !!  28         help
                                                   >>  29           The number of hardware counters is limited. The multiplexing
                                                   >>  30           feature enables OProfile to gather more events than counters
                                                   >>  31           are provided by the hardware. This is realized by switching
                                                   >>  32           between events at an user specified time interval.
 49                                                    33 
 50 config HOTPLUG_SPLIT_STARTUP                   !!  34           If unsure, say N.
 51         bool                                   << 
 52         select HOTPLUG_CORE_SYNC_FULL          << 
 53                                                    35 
 54 config HOTPLUG_PARALLEL                        !!  36 config HAVE_OPROFILE
 55         bool                                       37         bool
 56         select HOTPLUG_SPLIT_STARTUP           << 
 57                                                    38 
 58 config GENERIC_ENTRY                           !!  39 config OPROFILE_NMI_TIMER
 59         bool                                   !!  40         def_bool y
                                                   >>  41         depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64
 60                                                    42 
 61 config KPROBES                                     43 config KPROBES
 62         bool "Kprobes"                             44         bool "Kprobes"
                                                   >>  45         depends on MODULES
 63         depends on HAVE_KPROBES                    46         depends on HAVE_KPROBES
 64         select KALLSYMS                            47         select KALLSYMS
 65         select EXECMEM                         << 
 66         select NEED_TASKS_RCU                  << 
 67         help                                       48         help
 68           Kprobes allows you to trap at almost     49           Kprobes allows you to trap at almost any kernel address and
 69           execute a callback function.  regist     50           execute a callback function.  register_kprobe() establishes
 70           a probepoint and specifies the callb     51           a probepoint and specifies the callback.  Kprobes is useful
 71           for kernel debugging, non-intrusive      52           for kernel debugging, non-intrusive instrumentation and testing.
 72           If in doubt, say "N".                    53           If in doubt, say "N".
 73                                                    54 
 74 config JUMP_LABEL                                  55 config JUMP_LABEL
 75         bool "Optimize very unlikely/likely br !!  56        bool "Optimize very unlikely/likely branches"
 76         depends on HAVE_ARCH_JUMP_LABEL        !!  57        depends on HAVE_ARCH_JUMP_LABEL
 77         select OBJTOOL if HAVE_JUMP_LABEL_HACK !!  58        help
 78         help                                   !!  59          This option enables a transparent branch optimization that
 79           This option enables a transparent br !!  60          makes certain almost-always-true or almost-always-false branch
 80           makes certain almost-always-true or  !!  61          conditions even cheaper to execute within the kernel.
 81           conditions even cheaper to execute w !!  62 
 82                                                !!  63          Certain performance-sensitive kernel code, such as trace points,
 83           Certain performance-sensitive kernel !!  64          scheduler functionality, networking code and KVM have such
 84           scheduler functionality, networking  !!  65          branches and include support for this optimization technique.
 85           branches and include support for thi !!  66 
 86                                                !!  67          If it is detected that the compiler has support for "asm goto",
 87           If it is detected that the compiler  !!  68          the kernel will compile such branches with just a nop
 88           the kernel will compile such branche !!  69          instruction. When the condition flag is toggled to true, the
 89           instruction. When the condition flag !!  70          nop will be converted to a jump instruction to execute the
 90           nop will be converted to a jump inst !!  71          conditional block of instructions.
 91           conditional block of instructions.   !!  72 
 92                                                !!  73          This technique lowers overhead and stress on the branch prediction
 93           This technique lowers overhead and s !!  74          of the processor and generally makes the kernel faster. The update
 94           of the processor and generally makes !!  75          of the condition is slower, but those are always very rare.
 95           of the condition is slower, but thos << 
 96                                                    76 
 97           ( On 32-bit x86, the necessary optio !!  77          ( On 32-bit x86, the necessary options added to the compiler
 98             flags may increase the size of the !!  78            flags may increase the size of the kernel slightly. )
 99                                                    79 
100 config STATIC_KEYS_SELFTEST                        80 config STATIC_KEYS_SELFTEST
101         bool "Static key selftest"                 81         bool "Static key selftest"
102         depends on JUMP_LABEL                      82         depends on JUMP_LABEL
103         help                                       83         help
104           Boot time self-test of the branch pa     84           Boot time self-test of the branch patching code.
105                                                    85 
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                                   86 config OPTPROBES
113         def_bool y                                 87         def_bool y
114         depends on KPROBES && HAVE_OPTPROBES       88         depends on KPROBES && HAVE_OPTPROBES
115         select NEED_TASKS_RCU                  !!  89         depends on !PREEMPT
116                                                    90 
117 config KPROBES_ON_FTRACE                           91 config KPROBES_ON_FTRACE
118         def_bool y                                 92         def_bool y
119         depends on KPROBES && HAVE_KPROBES_ON_     93         depends on KPROBES && HAVE_KPROBES_ON_FTRACE
120         depends on DYNAMIC_FTRACE_WITH_REGS        94         depends on DYNAMIC_FTRACE_WITH_REGS
121         help                                       95         help
122           If function tracer is enabled and th !!  96          If function tracer is enabled and the arch supports full
123           passing of pt_regs to function traci !!  97          passing of pt_regs to function tracing, then kprobes can
124           optimize on top of function tracing. !!  98          optimize on top of function tracing.
125                                                    99 
126 config UPROBES                                    100 config UPROBES
127         def_bool n                                101         def_bool n
128         depends on ARCH_SUPPORTS_UPROBES          102         depends on ARCH_SUPPORTS_UPROBES
129         help                                      103         help
130           Uprobes is the user-space counterpar    104           Uprobes is the user-space counterpart to kprobes: they
131           enable instrumentation applications     105           enable instrumentation applications (such as 'perf probe')
132           to establish unintrusive probes in u    106           to establish unintrusive probes in user-space binaries and
133           libraries, by executing handler func    107           libraries, by executing handler functions when the probes
134           are hit by user-space applications.     108           are hit by user-space applications.
135                                                   109 
136           ( These probes come in the form of s    110           ( These probes come in the form of single-byte breakpoints,
137             managed by the kernel and kept tra    111             managed by the kernel and kept transparent to the probed
138             application. )                        112             application. )
139                                                   113 
140 config HAVE_64BIT_ALIGNED_ACCESS                  114 config HAVE_64BIT_ALIGNED_ACCESS
141         def_bool 64BIT && !HAVE_EFFICIENT_UNAL    115         def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
142         help                                      116         help
143           Some architectures require 64 bit ac    117           Some architectures require 64 bit accesses to be 64 bit
144           aligned, which also requires structs    118           aligned, which also requires structs containing 64 bit values
145           to be 64 bit aligned too. This inclu    119           to be 64 bit aligned too. This includes some 32 bit
146           architectures which can do 64 bit ac    120           architectures which can do 64 bit accesses, as well as 64 bit
147           architectures without unaligned acce    121           architectures without unaligned access.
148                                                   122 
149           This symbol should be selected by an    123           This symbol should be selected by an architecture if 64 bit
150           accesses are required to be 64 bit a    124           accesses are required to be 64 bit aligned in this way even
151           though it is not a 64 bit architectu    125           though it is not a 64 bit architecture.
152                                                   126 
153           See Documentation/core-api/unaligned !! 127           See Documentation/unaligned-memory-access.txt for more
154           more information on the topic of una !! 128           information on the topic of unaligned memory accesses.
155                                                   129 
156 config HAVE_EFFICIENT_UNALIGNED_ACCESS            130 config HAVE_EFFICIENT_UNALIGNED_ACCESS
157         bool                                      131         bool
158         help                                      132         help
159           Some architectures are unable to per    133           Some architectures are unable to perform unaligned accesses
160           without the use of get_unaligned/put    134           without the use of get_unaligned/put_unaligned. Others are
161           unable to perform such accesses effi    135           unable to perform such accesses efficiently (e.g. trap on
162           unaligned access and require fixing     136           unaligned access and require fixing it up in the exception
163           handler.)                               137           handler.)
164                                                   138 
165           This symbol should be selected by an    139           This symbol should be selected by an architecture if it can
166           perform unaligned accesses efficient    140           perform unaligned accesses efficiently to allow different
167           code paths to be selected for these     141           code paths to be selected for these cases. Some network
168           drivers, for example, could opt to n    142           drivers, for example, could opt to not fix up alignment
169           problems with received packets if do    143           problems with received packets if doing so would not help
170           much.                                   144           much.
171                                                   145 
172           See Documentation/core-api/unaligned !! 146           See Documentation/unaligned-memory-access.txt for more
173           information on the topic of unaligne    147           information on the topic of unaligned memory accesses.
174                                                   148 
175 config ARCH_USE_BUILTIN_BSWAP                     149 config ARCH_USE_BUILTIN_BSWAP
176         bool                                   !! 150        bool
177         help                                   !! 151        help
178           Modern versions of GCC (since 4.4) h !! 152          Modern versions of GCC (since 4.4) have builtin functions
179           for handling byte-swapping. Using th !! 153          for handling byte-swapping. Using these, instead of the old
180           inline assembler that the architectu !! 154          inline assembler that the architecture code provides in the
181           __arch_bswapXX() macros, allows the  !! 155          __arch_bswapXX() macros, allows the compiler to see what's
182           happening and offers more opportunit !! 156          happening and offers more opportunity for optimisation. In
183           particular, the compiler will be abl !! 157          particular, the compiler will be able to combine the byteswap
184           with a nearby load or store and use  !! 158          with a nearby load or store and use load-and-swap or
185           store-and-swap instructions if the a !! 159          store-and-swap instructions if the architecture has them. It
186           should almost *never* result in code !! 160          should almost *never* result in code which is worse than the
187           hand-coded assembler in <asm/swab.h> !! 161          hand-coded assembler in <asm/swab.h>.  But just in case it
188           does, the use of the builtins is opt !! 162          does, the use of the builtins is optional.
189                                                !! 163 
190           Any architecture with load-and-swap  !! 164          Any architecture with load-and-swap or store-and-swap
191           instructions should set this. And it !! 165          instructions should set this. And it shouldn't hurt to set it
192           on architectures that don't have suc !! 166          on architectures that don't have such instructions.
193                                                   167 
194 config KRETPROBES                                 168 config KRETPROBES
195         def_bool y                                169         def_bool y
196         depends on KPROBES && (HAVE_KRETPROBES !! 170         depends on KPROBES && HAVE_KRETPROBES
197                                                << 
198 config KRETPROBE_ON_RETHOOK                    << 
199         def_bool y                             << 
200         depends on HAVE_RETHOOK                << 
201         depends on KRETPROBES                  << 
202         select RETHOOK                         << 
203                                                   171 
204 config USER_RETURN_NOTIFIER                       172 config USER_RETURN_NOTIFIER
205         bool                                      173         bool
206         depends on HAVE_USER_RETURN_NOTIFIER      174         depends on HAVE_USER_RETURN_NOTIFIER
207         help                                      175         help
208           Provide a kernel-internal notificati    176           Provide a kernel-internal notification when a cpu is about to
209           switch to user mode.                    177           switch to user mode.
210                                                   178 
211 config HAVE_IOREMAP_PROT                          179 config HAVE_IOREMAP_PROT
212         bool                                      180         bool
213                                                   181 
214 config HAVE_KPROBES                               182 config HAVE_KPROBES
215         bool                                      183         bool
216                                                   184 
217 config HAVE_KRETPROBES                            185 config HAVE_KRETPROBES
218         bool                                      186         bool
219                                                   187 
220 config HAVE_OPTPROBES                             188 config HAVE_OPTPROBES
221         bool                                      189         bool
222                                                   190 
223 config HAVE_KPROBES_ON_FTRACE                     191 config HAVE_KPROBES_ON_FTRACE
224         bool                                      192         bool
225                                                   193 
226 config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE    << 
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           << 
235         bool                                   << 
236                                                << 
237 config HAVE_NMI                                   194 config HAVE_NMI
238         bool                                      195         bool
239                                                   196 
240 config HAVE_FUNCTION_DESCRIPTORS               !! 197 config HAVE_NMI_WATCHDOG
241         bool                                   !! 198         depends on HAVE_NMI
242                                                << 
243 config TRACE_IRQFLAGS_SUPPORT                  << 
244         bool                                      199         bool
245                                                << 
246 config TRACE_IRQFLAGS_NMI_SUPPORT              << 
247         bool                                   << 
248                                                << 
249 #                                                 200 #
250 # An arch should select this if it provides al    201 # An arch should select this if it provides all these things:
251 #                                                 202 #
252 #       task_pt_regs()          in asm/process    203 #       task_pt_regs()          in asm/processor.h or asm/ptrace.h
253 #       arch_has_single_step()  if there is ha    204 #       arch_has_single_step()  if there is hardware single-step support
254 #       arch_has_block_step()   if there is ha    205 #       arch_has_block_step()   if there is hardware block-step support
255 #       asm/syscall.h           supplying asm-    206 #       asm/syscall.h           supplying asm-generic/syscall.h interface
256 #       linux/regset.h          user_regset in    207 #       linux/regset.h          user_regset interfaces
257 #       CORE_DUMP_USE_REGSET    #define'd in l    208 #       CORE_DUMP_USE_REGSET    #define'd in linux/elf.h
258 #       TIF_SYSCALL_TRACE       calls ptrace_r !! 209 #       TIF_SYSCALL_TRACE       calls tracehook_report_syscall_{entry,exit}
259 #       TIF_NOTIFY_RESUME       calls resume_u !! 210 #       TIF_NOTIFY_RESUME       calls tracehook_notify_resume()
                                                   >> 211 #       signal delivery         calls tracehook_signal_handler()
260 #                                                 212 #
261 config HAVE_ARCH_TRACEHOOK                        213 config HAVE_ARCH_TRACEHOOK
262         bool                                      214         bool
263                                                   215 
264 config HAVE_DMA_CONTIGUOUS                        216 config HAVE_DMA_CONTIGUOUS
265         bool                                      217         bool
266                                                   218 
267 config GENERIC_SMP_IDLE_THREAD                    219 config GENERIC_SMP_IDLE_THREAD
268         bool                                   !! 220        bool
269                                                   221 
270 config GENERIC_IDLE_POLL_SETUP                    222 config GENERIC_IDLE_POLL_SETUP
271         bool                                   !! 223        bool
272                                                   224 
273 config ARCH_HAS_FORTIFY_SOURCE                 !! 225 # Select if arch init_task initializer is different to init/init_task.c
274         bool                                   !! 226 config ARCH_INIT_TASK
275         help                                   !! 227        bool
276           An architecture should select this w << 
277           build and run with CONFIG_FORTIFY_SO << 
278                                                << 
279 #                                              << 
280 # Select if the arch provides a historic keepi << 
281 # command line option                          << 
282 #                                              << 
283 config ARCH_HAS_KEEPINITRD                     << 
284         bool                                   << 
285                                                   228 
286 # Select if arch has all set_memory_ro/rw/x/nx !! 229 # Select if arch has its private alloc_task_struct() function
287 config ARCH_HAS_SET_MEMORY                     !! 230 config ARCH_TASK_STRUCT_ALLOCATOR
288         bool                                      231         bool
289                                                   232 
290 # Select if arch has all set_direct_map_invali !! 233 # Select if arch has its private alloc_thread_stack() function
291 config ARCH_HAS_SET_DIRECT_MAP                 !! 234 config ARCH_THREAD_STACK_ALLOCATOR
292         bool                                      235         bool
293                                                   236 
294 #                                              << 
295 # Select if the architecture provides the arch << 
296 # either provide an uncached segment alias for << 
297 # to remap the page tables in place.           << 
298 #                                              << 
299 config ARCH_HAS_DMA_SET_UNCACHED               << 
300         bool                                   << 
301                                                << 
302 #                                              << 
303 # Select if the architectures provides the arc << 
304 # to undo an in-place page table remap for unc << 
305 #                                              << 
306 config ARCH_HAS_DMA_CLEAR_UNCACHED             << 
307         bool                                   << 
308                                                << 
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       << 
318         bool                                   << 
319         help                                   << 
320           An architecture should select this t << 
321           knowledge about what region of the t << 
322           whitelisted for copying to userspace << 
323           FPU registers. Specifically, arch_th << 
324           should be implemented. Without this, << 
325           field in task_struct will be left wh << 
326                                                << 
327 # Select if arch wants to size task_struct dyn    237 # Select if arch wants to size task_struct dynamically via arch_task_struct_size:
328 config ARCH_WANTS_DYNAMIC_TASK_STRUCT             238 config ARCH_WANTS_DYNAMIC_TASK_STRUCT
329         bool                                      239         bool
330                                                   240 
331 config ARCH_WANTS_NO_INSTR                     << 
332         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                                                << 
338 config ARCH_32BIT_OFF_T                        << 
339         bool                                   << 
340         depends on !64BIT                      << 
341         help                                   << 
342           All new 32-bit architectures should  << 
343           userspace side which corresponds to  << 
344           is the requirement for modern ABIs.  << 
345           still support 32-bit off_t. This opt << 
346           architectures explicitly.            << 
347                                                << 
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             241 config HAVE_REGS_AND_STACK_ACCESS_API
360         bool                                      242         bool
361         help                                      243         help
362           This symbol should be selected by an !! 244           This symbol should be selected by an architecure if it supports
363           the API needed to access registers a    245           the API needed to access registers and stack entries from pt_regs,
364           declared in asm/ptrace.h                246           declared in asm/ptrace.h
365           For example the kprobes-based event     247           For example the kprobes-based event tracer needs this API.
366                                                   248 
367 config HAVE_RSEQ                               !! 249 config HAVE_CLK
368         bool                                   << 
369         depends on HAVE_REGS_AND_STACK_ACCESS_ << 
370         help                                   << 
371           This symbol should be selected by an << 
372           supports an implementation of restar << 
373                                                << 
374 config HAVE_RUST                               << 
375         bool                                      250         bool
376         help                                      251         help
377           This symbol should be selected by an !! 252           The <linux/clk.h> calls support software clock gating and
378           supports Rust.                       !! 253           thus are a key power management tool on many systems.
379                                                   254 
380 config HAVE_FUNCTION_ARG_ACCESS_API            !! 255 config HAVE_DMA_API_DEBUG
381         bool                                      256         bool
382         help                                   << 
383           This symbol should be selected by an << 
384           the API needed to access function ar << 
385           declared in asm/ptrace.h             << 
386                                                   257 
387 config HAVE_HW_BREAKPOINT                         258 config HAVE_HW_BREAKPOINT
388         bool                                      259         bool
389         depends on PERF_EVENTS                    260         depends on PERF_EVENTS
390                                                   261 
391 config HAVE_MIXED_BREAKPOINTS_REGS                262 config HAVE_MIXED_BREAKPOINTS_REGS
392         bool                                      263         bool
393         depends on HAVE_HW_BREAKPOINT             264         depends on HAVE_HW_BREAKPOINT
394         help                                      265         help
395           Depending on the arch implementation    266           Depending on the arch implementation of hardware breakpoints,
396           some of them have separate registers    267           some of them have separate registers for data and instruction
397           breakpoints addresses, others have m    268           breakpoints addresses, others have mixed registers to store
398           them but define the access type in a    269           them but define the access type in a control register.
399           Select this option if your arch impl    270           Select this option if your arch implements breakpoints under the
400           latter fashion.                         271           latter fashion.
401                                                   272 
402 config HAVE_USER_RETURN_NOTIFIER                  273 config HAVE_USER_RETURN_NOTIFIER
403         bool                                      274         bool
404                                                   275 
405 config HAVE_PERF_EVENTS_NMI                       276 config HAVE_PERF_EVENTS_NMI
406         bool                                      277         bool
407         help                                      278         help
408           System hardware can generate an NMI     279           System hardware can generate an NMI using the perf event
409           subsystem.  Also has support for cal    280           subsystem.  Also has support for calculating CPU cycle events
410           to determine how many clock cycles i    281           to determine how many clock cycles in a given period.
411                                                   282 
412 config HAVE_HARDLOCKUP_DETECTOR_PERF           << 
413         bool                                   << 
414         depends on HAVE_PERF_EVENTS_NMI        << 
415         help                                   << 
416           The arch chooses to use the generic  << 
417           detector. Must define HAVE_PERF_EVEN << 
418                                                << 
419 config HAVE_HARDLOCKUP_DETECTOR_ARCH           << 
420         bool                                   << 
421         help                                   << 
422           The arch provides its own hardlockup << 
423           of the generic ones.                 << 
424                                                << 
425           It uses the same command line parame << 
426           as the generic hardlockup detectors. << 
427                                                << 
428 config HAVE_PERF_REGS                             283 config HAVE_PERF_REGS
429         bool                                      284         bool
430         help                                      285         help
431           Support selective register dumps for    286           Support selective register dumps for perf events. This includes
432           bit-mapping of each registers and a     287           bit-mapping of each registers and a unique architecture id.
433                                                   288 
434 config HAVE_PERF_USER_STACK_DUMP                  289 config HAVE_PERF_USER_STACK_DUMP
435         bool                                      290         bool
436         help                                      291         help
437           Support user stack dumps for perf ev    292           Support user stack dumps for perf event samples. This needs
438           access to the user stack pointer whi    293           access to the user stack pointer which is not unified across
439           architectures.                          294           architectures.
440                                                   295 
441 config HAVE_ARCH_JUMP_LABEL                       296 config HAVE_ARCH_JUMP_LABEL
442         bool                                      297         bool
443                                                   298 
444 config HAVE_ARCH_JUMP_LABEL_RELATIVE           !! 299 config HAVE_RCU_TABLE_FREE
445         bool                                   << 
446                                                << 
447 config MMU_GATHER_TABLE_FREE                   << 
448         bool                                   << 
449                                                << 
450 config MMU_GATHER_RCU_TABLE_FREE               << 
451         bool                                   << 
452         select MMU_GATHER_TABLE_FREE           << 
453                                                << 
454 config MMU_GATHER_PAGE_SIZE                    << 
455         bool                                   << 
456                                                << 
457 config MMU_GATHER_NO_RANGE                     << 
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                                      300         bool
509                                                   301 
510 config ARCH_HAVE_NMI_SAFE_CMPXCHG                 302 config ARCH_HAVE_NMI_SAFE_CMPXCHG
511         bool                                      303         bool
512                                                   304 
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                   305 config HAVE_ALIGNED_STRUCT_PAGE
526         bool                                      306         bool
527         help                                      307         help
528           This makes sure that struct pages ar    308           This makes sure that struct pages are double word aligned and that
529           e.g. the SLUB allocator can perform     309           e.g. the SLUB allocator can perform double word atomic operations
530           on a struct page for better performa    310           on a struct page for better performance. However selecting this
531           might increase the size of a struct     311           might increase the size of a struct page by a word.
532                                                   312 
533 config HAVE_CMPXCHG_LOCAL                         313 config HAVE_CMPXCHG_LOCAL
534         bool                                      314         bool
535                                                   315 
536 config HAVE_CMPXCHG_DOUBLE                        316 config HAVE_CMPXCHG_DOUBLE
537         bool                                      317         bool
538                                                   318 
539 config ARCH_WEAK_RELEASE_ACQUIRE               << 
540         bool                                   << 
541                                                << 
542 config ARCH_WANT_IPC_PARSE_VERSION                319 config ARCH_WANT_IPC_PARSE_VERSION
543         bool                                      320         bool
544                                                   321 
545 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION         322 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
546         bool                                      323         bool
547                                                   324 
548 config ARCH_WANT_OLD_COMPAT_IPC                   325 config ARCH_WANT_OLD_COMPAT_IPC
549         select ARCH_WANT_COMPAT_IPC_PARSE_VERS    326         select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
550         bool                                      327         bool
551                                                   328 
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                   329 config HAVE_ARCH_SECCOMP_FILTER
564         bool                                      330         bool
565         select HAVE_ARCH_SECCOMP               << 
566         help                                      331         help
567           An arch should select this symbol if    332           An arch should select this symbol if it provides all of these things:
568           - all the requirements for HAVE_ARCH << 
569           - syscall_get_arch()                    333           - syscall_get_arch()
570           - syscall_get_arguments()               334           - syscall_get_arguments()
571           - syscall_rollback()                    335           - syscall_rollback()
572           - syscall_set_return_value()            336           - syscall_set_return_value()
573           - SIGSYS siginfo_t support              337           - SIGSYS siginfo_t support
574           - secure_computing is called from a     338           - secure_computing is called from a ptrace_event()-safe context
575           - secure_computing return value is c    339           - secure_computing return value is checked and a return value of -1
576             results in the system call being s    340             results in the system call being skipped immediately.
577           - seccomp syscall wired up              341           - 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                                                   342 
599 config SECCOMP_FILTER                             343 config SECCOMP_FILTER
600         def_bool y                                344         def_bool y
601         depends on HAVE_ARCH_SECCOMP_FILTER &&    345         depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
602         help                                      346         help
603           Enable tasks to build secure computi    347           Enable tasks to build secure computing environments defined
604           in terms of Berkeley Packet Filter p    348           in terms of Berkeley Packet Filter programs which implement
605           task-defined system call filtering p    349           task-defined system call filtering polices.
606                                                   350 
607           See Documentation/userspace-api/secc !! 351           See Documentation/prctl/seccomp_filter.txt for details.
608                                                   352 
609 config SECCOMP_CACHE_DEBUG                     !! 353 config HAVE_GCC_PLUGINS
610         bool "Show seccomp filter cache status !! 354         bool
611         depends on SECCOMP_FILTER && !HAVE_SPA !! 355         help
612         depends on PROC_FS                     !! 356           An arch should select this symbol if it supports building with
613         help                                   !! 357           GCC plugins.
614           This enables the /proc/pid/seccomp_c << 
615           seccomp cache data. The file format  << 
616           the file requires CAP_SYS_ADMIN.     << 
617                                                   358 
618           This option is for debugging only. E !! 359 menuconfig GCC_PLUGINS
619           an adversary may be able to infer th !! 360         bool "GCC plugins"
                                                   >> 361         depends on HAVE_GCC_PLUGINS
                                                   >> 362         depends on !COMPILE_TEST
                                                   >> 363         help
                                                   >> 364           GCC plugins are loadable modules that provide extra features to the
                                                   >> 365           compiler. They are useful for runtime instrumentation and static analysis.
620                                                   366 
621           If unsure, say N.                    !! 367           See Documentation/gcc-plugins.txt for details.
622                                                   368 
623 config HAVE_ARCH_STACKLEAK                     !! 369 config GCC_PLUGIN_CYC_COMPLEXITY
624         bool                                   !! 370         bool "Compute the cyclomatic complexity of a function" if EXPERT
                                                   >> 371         depends on GCC_PLUGINS
                                                   >> 372         depends on !COMPILE_TEST
625         help                                      373         help
626           An architecture should select this i !! 374           The complexity M of a function's control flow graph is defined as:
627           fills the used part of the kernel st !! 375            M = E - N + 2P
628           value before returning from system c !! 376           where
                                                   >> 377 
                                                   >> 378           E = the number of edges
                                                   >> 379           N = the number of nodes
                                                   >> 380           P = the number of connected components (exit nodes).
                                                   >> 381 
                                                   >> 382           Enabling this plugin reports the complexity to stderr during the
                                                   >> 383           build. It mainly serves as a simple example of how to create a
                                                   >> 384           gcc plugin for the kernel.
                                                   >> 385 
                                                   >> 386 config GCC_PLUGIN_SANCOV
                                                   >> 387         bool
                                                   >> 388         depends on GCC_PLUGINS
                                                   >> 389         help
                                                   >> 390           This plugin inserts a __sanitizer_cov_trace_pc() call at the start of
                                                   >> 391           basic blocks. It supports all gcc versions with plugin support (from
                                                   >> 392           gcc-4.5 on). It is based on the commit "Add fuzzing coverage support"
                                                   >> 393           by Dmitry Vyukov <dvyukov@google.com>.
                                                   >> 394 
                                                   >> 395 config GCC_PLUGIN_LATENT_ENTROPY
                                                   >> 396         bool "Generate some entropy during boot and runtime"
                                                   >> 397         depends on GCC_PLUGINS
                                                   >> 398         help
                                                   >> 399           By saying Y here the kernel will instrument some kernel code to
                                                   >> 400           extract some entropy from both original and artificially created
                                                   >> 401           program state.  This will help especially embedded systems where
                                                   >> 402           there is little 'natural' source of entropy normally.  The cost
                                                   >> 403           is some slowdown of the boot process (about 0.5%) and fork and
                                                   >> 404           irq processing.
                                                   >> 405 
                                                   >> 406           Note that entropy extracted this way is not cryptographically
                                                   >> 407           secure!
                                                   >> 408 
                                                   >> 409           This plugin was ported from grsecurity/PaX. More information at:
                                                   >> 410            * https://grsecurity.net/
                                                   >> 411            * https://pax.grsecurity.net/
629                                                   412 
630 config HAVE_STACKPROTECTOR                     !! 413 config HAVE_CC_STACKPROTECTOR
631         bool                                      414         bool
632         help                                      415         help
633           An arch should select this symbol if    416           An arch should select this symbol if:
                                                   >> 417           - its compiler supports the -fstack-protector option
634           - it has implemented a stack canary     418           - it has implemented a stack canary (e.g. __stack_chk_guard)
635                                                   419 
636 config STACKPROTECTOR                          !! 420 config CC_STACKPROTECTOR
637         bool "Stack Protector buffer overflow  !! 421         def_bool n
638         depends on HAVE_STACKPROTECTOR         !! 422         help
639         depends on $(cc-option,-fstack-protect !! 423           Set when a stack-protector mode is enabled, so that the build
640         default y                              !! 424           can enable kernel-side support for the GCC feature.
                                                   >> 425 
                                                   >> 426 choice
                                                   >> 427         prompt "Stack Protector buffer overflow detection"
                                                   >> 428         depends on HAVE_CC_STACKPROTECTOR
                                                   >> 429         default CC_STACKPROTECTOR_NONE
641         help                                      430         help
642           This option turns on the "stack-prot    431           This option turns on the "stack-protector" GCC feature. This
643           feature puts, at the beginning of fu    432           feature puts, at the beginning of functions, a canary value on
644           the stack just before the return add    433           the stack just before the return address, and validates
645           the value just before actually retur    434           the value just before actually returning.  Stack based buffer
646           overflows (that need to overwrite th    435           overflows (that need to overwrite this return address) now also
647           overwrite the canary, which gets det    436           overwrite the canary, which gets detected and the attack is then
648           neutralized via a kernel panic.         437           neutralized via a kernel panic.
649                                                   438 
                                                   >> 439 config CC_STACKPROTECTOR_NONE
                                                   >> 440         bool "None"
                                                   >> 441         help
                                                   >> 442           Disable "stack-protector" GCC feature.
                                                   >> 443 
                                                   >> 444 config CC_STACKPROTECTOR_REGULAR
                                                   >> 445         bool "Regular"
                                                   >> 446         select CC_STACKPROTECTOR
                                                   >> 447         help
650           Functions will have the stack-protec    448           Functions will have the stack-protector canary logic added if they
651           have an 8-byte or larger character a    449           have an 8-byte or larger character array on the stack.
652                                                   450 
653           This feature requires gcc version 4.    451           This feature requires gcc version 4.2 or above, or a distribution
654           gcc with the feature backported ("-f    452           gcc with the feature backported ("-fstack-protector").
655                                                   453 
656           On an x86 "defconfig" build, this fe    454           On an x86 "defconfig" build, this feature adds canary checks to
657           about 3% of all kernel functions, wh    455           about 3% of all kernel functions, which increases kernel code size
658           by about 0.3%.                          456           by about 0.3%.
659                                                   457 
660 config STACKPROTECTOR_STRONG                   !! 458 config CC_STACKPROTECTOR_STRONG
661         bool "Strong Stack Protector"          !! 459         bool "Strong"
662         depends on STACKPROTECTOR              !! 460         select CC_STACKPROTECTOR
663         depends on $(cc-option,-fstack-protect << 
664         default y                              << 
665         help                                      461         help
666           Functions will have the stack-protec    462           Functions will have the stack-protector canary logic added in any
667           of the following conditions:            463           of the following conditions:
668                                                   464 
669           - local variable's address used as p    465           - local variable's address used as part of the right hand side of an
670             assignment or function argument       466             assignment or function argument
671           - local variable is an array (or uni    467           - local variable is an array (or union containing an array),
672             regardless of array type or length    468             regardless of array type or length
673           - uses register local variables         469           - uses register local variables
674                                                   470 
675           This feature requires gcc version 4.    471           This feature requires gcc version 4.9 or above, or a distribution
676           gcc with the feature backported ("-f    472           gcc with the feature backported ("-fstack-protector-strong").
677                                                   473 
678           On an x86 "defconfig" build, this fe    474           On an x86 "defconfig" build, this feature adds canary checks to
679           about 20% of all kernel functions, w    475           about 20% of all kernel functions, which increases the kernel code
680           size by about 2%.                       476           size by about 2%.
681                                                   477 
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                                         478 endchoice
804                                                   479 
805 config ARCH_SUPPORTS_CFI_CLANG                 !! 480 config THIN_ARCHIVES
806         bool                                      481         bool
807         help                                      482         help
808           An architecture should select this o !! 483           Select this if the architecture wants to use thin archives
809           Control-Flow Integrity (CFI) checkin !! 484           instead of ld -r to create the built-in.o files.
810                                                   485 
811 config ARCH_USES_CFI_TRAPS                     !! 486 config LD_DEAD_CODE_DATA_ELIMINATION
812         bool                                      487         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                                      488         help
833           When selected, Control Flow Integrit !! 489           Select this if the architecture wants to do dead code and
834           warning instead of a kernel panic. T !! 490           data elimination with the linker by compiling with
835           for finding indirect call type misma !! 491           -ffunction-sections -fdata-sections and linking with
                                                   >> 492           --gc-sections.
836                                                   493 
837           If unsure, say N.                    !! 494           This requires that the arch annotates or otherwise protects
                                                   >> 495           its external entry points from being discarded. Linker scripts
                                                   >> 496           must also merge .text.*, .data.*, and .bss.* correctly into
                                                   >> 497           output sections. Care must be taken not to pull in unrelated
                                                   >> 498           sections (e.g., '.text.init'). Typically '.' in section names
                                                   >> 499           is used to distinguish them from label names / C identifiers.
838                                                   500 
839 config HAVE_ARCH_WITHIN_STACK_FRAMES              501 config HAVE_ARCH_WITHIN_STACK_FRAMES
840         bool                                      502         bool
841         help                                      503         help
842           An architecture should select this i    504           An architecture should select this if it can walk the kernel stack
843           frames to determine if an object is     505           frames to determine if an object is part of either the arguments
844           or local variables (i.e. that it exc    506           or local variables (i.e. that it excludes saved return addresses,
845           and similar) by implementing an inli    507           and similar) by implementing an inline arch_within_stack_frames(),
846           which is used by CONFIG_HARDENED_USE    508           which is used by CONFIG_HARDENED_USERCOPY.
847                                                   509 
848 config HAVE_CONTEXT_TRACKING_USER              !! 510 config HAVE_CONTEXT_TRACKING
849         bool                                      511         bool
850         help                                      512         help
851           Provide kernel/user boundaries probe    513           Provide kernel/user boundaries probes necessary for subsystems
852           that need it, such as userspace RCU     514           that need it, such as userspace RCU extended quiescent state.
853           Syscalls need to be wrapped inside u !! 515           Syscalls need to be wrapped inside user_exit()-user_enter() through
854           optimized behind static key or throu !! 516           the slow path using TIF_NOHZ flag. Exceptions handlers must be
855           flag. Exceptions handlers must be wr !! 517           wrapped as well. Irqs are already protected inside
856           protected inside ct_irq_enter/ct_irq !! 518           rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on
857           handling on irq exit still need to b !! 519           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                                                   520 
882 config HAVE_VIRT_CPU_ACCOUNTING                   521 config HAVE_VIRT_CPU_ACCOUNTING
883         bool                                      522         bool
884                                                   523 
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                    524 config ARCH_HAS_SCALED_CPUTIME
892         bool                                      525         bool
893                                                   526 
894 config HAVE_VIRT_CPU_ACCOUNTING_GEN               527 config HAVE_VIRT_CPU_ACCOUNTING_GEN
895         bool                                      528         bool
896         default y if 64BIT                        529         default y if 64BIT
897         help                                      530         help
898           With VIRT_CPU_ACCOUNTING_GEN, cputim    531           With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
899           Before enabling this option, arch co    532           Before enabling this option, arch code must be audited
900           to ensure there are no races in conc    533           to ensure there are no races in concurrent read/write of
901           cputime_t. For example, reading/writ    534           cputime_t. For example, reading/writing 64-bit cputime_t on
902           some 32-bit arches may require multi    535           some 32-bit arches may require multiple accesses, so proper
903           locking is needed to protect against    536           locking is needed to protect against concurrent accesses.
904                                                   537 
                                                   >> 538 
905 config HAVE_IRQ_TIME_ACCOUNTING                   539 config HAVE_IRQ_TIME_ACCOUNTING
906         bool                                      540         bool
907         help                                      541         help
908           Archs need to ensure they use a high    542           Archs need to ensure they use a high enough resolution clock to
909           support irq time accounting and then    543           support irq time accounting and then call enable_sched_clock_irqtime().
910                                                   544 
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                           << 
919         bool                                   << 
920         help                                   << 
921           Archs that select this are able to m << 
922                                                << 
923 config HAVE_ARCH_TRANSPARENT_HUGEPAGE             545 config HAVE_ARCH_TRANSPARENT_HUGEPAGE
924         bool                                      546         bool
925                                                   547 
926 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD      << 
927         bool                                   << 
928                                                << 
929 config HAVE_ARCH_HUGE_VMAP                        548 config HAVE_ARCH_HUGE_VMAP
930         bool                                      549         bool
931                                                   550 
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                       551 config HAVE_ARCH_SOFT_DIRTY
953         bool                                      552         bool
954                                                   553 
955 config HAVE_MOD_ARCH_SPECIFIC                     554 config HAVE_MOD_ARCH_SPECIFIC
956         bool                                      555         bool
957         help                                      556         help
958           The arch uses struct mod_arch_specif    557           The arch uses struct mod_arch_specific to store data.  Many arches
959           just need a simple module loader wit    558           just need a simple module loader without arch specific data - those
960           should not enable this.                 559           should not enable this.
961                                                   560 
962 config MODULES_USE_ELF_RELA                       561 config MODULES_USE_ELF_RELA
963         bool                                      562         bool
964         help                                      563         help
965           Modules only use ELF RELA relocation    564           Modules only use ELF RELA relocations.  Modules with ELF REL
966           relocations will give an error.         565           relocations will give an error.
967                                                   566 
968 config MODULES_USE_ELF_REL                        567 config MODULES_USE_ELF_REL
969         bool                                      568         bool
970         help                                      569         help
971           Modules only use ELF REL relocations    570           Modules only use ELF REL relocations.  Modules with ELF RELA
972           relocations will give an error.         571           relocations will give an error.
973                                                   572 
974 config ARCH_WANTS_MODULES_DATA_IN_VMALLOC      !! 573 config HAVE_UNDERSCORE_SYMBOL_PREFIX
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                                      574         bool
982         help                                      575         help
983           For architectures that do not alloca !! 576           Some architectures generate an _ in front of C symbols; things like
984           boot, but rather require its initial !! 577           module loading and assembly files need to know about this.
985           enough entropy for module space rand << 
986           arm64.                               << 
987                                                   578 
988 config HAVE_IRQ_EXIT_ON_IRQ_STACK                 579 config HAVE_IRQ_EXIT_ON_IRQ_STACK
989         bool                                      580         bool
990         help                                      581         help
991           Architecture doesn't only execute th    582           Architecture doesn't only execute the irq handler on the irq stack
992           but also irq_exit(). This way we can    583           but also irq_exit(). This way we can process softirqs on this irq
993           stack instead of switching to a new     584           stack instead of switching to a new one when we call __do_softirq()
994           in the end of an hardirq.               585           in the end of an hardirq.
995           This spares a stack switch and impro    586           This spares a stack switch and improves cache usage on softirq
996           processing.                             587           processing.
997                                                   588 
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                            589 config PGTABLE_LEVELS
1015         int                                      590         int
1016         default 2                                591         default 2
1017                                                  592 
1018 config ARCH_HAS_ELF_RANDOMIZE                    593 config ARCH_HAS_ELF_RANDOMIZE
1019         bool                                     594         bool
1020         help                                     595         help
1021           An architecture supports choosing r    596           An architecture supports choosing randomized locations for
1022           stack, mmap, brk, and ET_DYN. Defin    597           stack, mmap, brk, and ET_DYN. Defined functions:
1023           - arch_mmap_rnd()                      598           - arch_mmap_rnd()
1024           - arch_randomize_brk()                 599           - arch_randomize_brk()
1025                                                  600 
1026 config HAVE_ARCH_MMAP_RND_BITS                   601 config HAVE_ARCH_MMAP_RND_BITS
1027         bool                                     602         bool
1028         help                                     603         help
1029           An arch should select this symbol i    604           An arch should select this symbol if it supports setting a variable
1030           number of bits for use in establish    605           number of bits for use in establishing the base address for mmap
1031           allocations, has MMU enabled and pr    606           allocations, has MMU enabled and provides values for both:
1032           - ARCH_MMAP_RND_BITS_MIN               607           - ARCH_MMAP_RND_BITS_MIN
1033           - ARCH_MMAP_RND_BITS_MAX               608           - ARCH_MMAP_RND_BITS_MAX
1034                                                  609 
1035 config HAVE_EXIT_THREAD                          610 config HAVE_EXIT_THREAD
1036         bool                                     611         bool
1037         help                                     612         help
1038           An architecture implements exit_thr    613           An architecture implements exit_thread.
1039                                                  614 
1040 config ARCH_MMAP_RND_BITS_MIN                    615 config ARCH_MMAP_RND_BITS_MIN
1041         int                                      616         int
1042                                                  617 
1043 config ARCH_MMAP_RND_BITS_MAX                    618 config ARCH_MMAP_RND_BITS_MAX
1044         int                                      619         int
1045                                                  620 
1046 config ARCH_MMAP_RND_BITS_DEFAULT                621 config ARCH_MMAP_RND_BITS_DEFAULT
1047         int                                      622         int
1048                                                  623 
1049 config ARCH_MMAP_RND_BITS                        624 config ARCH_MMAP_RND_BITS
1050         int "Number of bits to use for ASLR o    625         int "Number of bits to use for ASLR of mmap base address" if EXPERT
1051         range ARCH_MMAP_RND_BITS_MIN ARCH_MMA    626         range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
1052         default ARCH_MMAP_RND_BITS_DEFAULT if    627         default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
1053         default ARCH_MMAP_RND_BITS_MIN           628         default ARCH_MMAP_RND_BITS_MIN
1054         depends on HAVE_ARCH_MMAP_RND_BITS       629         depends on HAVE_ARCH_MMAP_RND_BITS
1055         help                                     630         help
1056           This value can be used to select th    631           This value can be used to select the number of bits to use to
1057           determine the random offset to the     632           determine the random offset to the base address of vma regions
1058           resulting from mmap allocations. Th    633           resulting from mmap allocations. This value will be bounded
1059           by the architecture's minimum and m    634           by the architecture's minimum and maximum supported values.
1060                                                  635 
1061           This value can be changed after boo    636           This value can be changed after boot using the
1062           /proc/sys/vm/mmap_rnd_bits tunable     637           /proc/sys/vm/mmap_rnd_bits tunable
1063                                                  638 
1064 config HAVE_ARCH_MMAP_RND_COMPAT_BITS            639 config HAVE_ARCH_MMAP_RND_COMPAT_BITS
1065         bool                                     640         bool
1066         help                                     641         help
1067           An arch should select this symbol i    642           An arch should select this symbol if it supports running applications
1068           in compatibility mode, supports set    643           in compatibility mode, supports setting a variable number of bits for
1069           use in establishing the base addres    644           use in establishing the base address for mmap allocations, has MMU
1070           enabled and provides values for bot    645           enabled and provides values for both:
1071           - ARCH_MMAP_RND_COMPAT_BITS_MIN        646           - ARCH_MMAP_RND_COMPAT_BITS_MIN
1072           - ARCH_MMAP_RND_COMPAT_BITS_MAX        647           - ARCH_MMAP_RND_COMPAT_BITS_MAX
1073                                                  648 
1074 config ARCH_MMAP_RND_COMPAT_BITS_MIN             649 config ARCH_MMAP_RND_COMPAT_BITS_MIN
1075         int                                      650         int
1076                                                  651 
1077 config ARCH_MMAP_RND_COMPAT_BITS_MAX             652 config ARCH_MMAP_RND_COMPAT_BITS_MAX
1078         int                                      653         int
1079                                                  654 
1080 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT         655 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1081         int                                      656         int
1082                                                  657 
1083 config ARCH_MMAP_RND_COMPAT_BITS                 658 config ARCH_MMAP_RND_COMPAT_BITS
1084         int "Number of bits to use for ASLR o    659         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    660         range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
1086         default ARCH_MMAP_RND_COMPAT_BITS_DEF    661         default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1087         default ARCH_MMAP_RND_COMPAT_BITS_MIN    662         default ARCH_MMAP_RND_COMPAT_BITS_MIN
1088         depends on HAVE_ARCH_MMAP_RND_COMPAT_    663         depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
1089         help                                     664         help
1090           This value can be used to select th    665           This value can be used to select the number of bits to use to
1091           determine the random offset to the     666           determine the random offset to the base address of vma regions
1092           resulting from mmap allocations for    667           resulting from mmap allocations for compatible applications This
1093           value will be bounded by the archit    668           value will be bounded by the architecture's minimum and maximum
1094           supported values.                      669           supported values.
1095                                                  670 
1096           This value can be changed after boo    671           This value can be changed after boot using the
1097           /proc/sys/vm/mmap_rnd_compat_bits t    672           /proc/sys/vm/mmap_rnd_compat_bits tunable
1098                                                  673 
1099 config HAVE_ARCH_COMPAT_MMAP_BASES            !! 674 config HAVE_COPY_THREAD_TLS
1100         bool                                     675         bool
1101         help                                     676         help
1102           This allows 64bit applications to i !! 677           Architecture provides copy_thread_tls to accept tls argument via
1103           and vice-versa 32-bit applications  !! 678           normal C parameter passing, rather than extracting the syscall
1104           Required for applications doing dif !! 679           argument from pt_regs.
1105                                               << 
1106 config HAVE_PAGE_SIZE_4KB                     << 
1107         bool                                  << 
1108                                               << 
1109 config HAVE_PAGE_SIZE_8KB                     << 
1110         bool                                  << 
1111                                               << 
1112 config HAVE_PAGE_SIZE_16KB                    << 
1113         bool                                  << 
1114                                               << 
1115 config HAVE_PAGE_SIZE_32KB                    << 
1116         bool                                  << 
1117                                               << 
1118 config HAVE_PAGE_SIZE_64KB                    << 
1119         bool                                  << 
1120                                               << 
1121 config HAVE_PAGE_SIZE_256KB                   << 
1122         bool                                  << 
1123                                               << 
1124 choice                                        << 
1125         prompt "MMU page size"                << 
1126                                               << 
1127 config PAGE_SIZE_4KB                          << 
1128         bool "4KiB pages"                     << 
1129         depends on HAVE_PAGE_SIZE_4KB         << 
1130         help                                  << 
1131           This option select the standard 4Ki << 
1132           available option on many architectu << 
1133           minimize memory consumption and is  << 
1134           memory systems.                     << 
1135           Some software that is written for x << 
1136           assumptions about the page size and << 
1137                                               << 
1138 config PAGE_SIZE_8KB                          << 
1139         bool "8KiB pages"                     << 
1140         depends on HAVE_PAGE_SIZE_8KB         << 
1141         help                                  << 
1142           This option is the only supported p << 
1143           processors, and can be slightly fas << 
1144                                               << 
1145 config PAGE_SIZE_16KB                         << 
1146         bool "16KiB pages"                    << 
1147         depends on HAVE_PAGE_SIZE_16KB        << 
1148         help                                  << 
1149           This option is usually a good compr << 
1150           consumption and performance for typ << 
1151           workloads, often saving a level of  << 
1152           to 4KB pages as well as reducing TL << 
1153           per-page operations in the kernel a << 
1154           page cache.                         << 
1155                                               << 
1156 config PAGE_SIZE_32KB                         << 
1157         bool "32KiB pages"                    << 
1158         depends on HAVE_PAGE_SIZE_32KB        << 
1159         help                                  << 
1160           Using 32KiB page size will result i << 
1161           kernel at the price of higher memor << 
1162           16KiB pages.  This option is availa << 
1163           Note that you will need a suitable  << 
1164           support this.                       << 
1165                                               << 
1166 config PAGE_SIZE_64KB                         << 
1167         bool "64KiB pages"                    << 
1168         depends on HAVE_PAGE_SIZE_64KB        << 
1169         help                                  << 
1170           Using 64KiB page size will result i << 
1171           kernel at the price of much higher  << 
1172           4KiB or 16KiB pages.                << 
1173           This is not suitable for general-pu << 
1174           better performance may be worth the << 
1175           supercomputing or database applicat << 
1176           large in-memory data rather than sm << 
1177                                               << 
1178 config PAGE_SIZE_256KB                        << 
1179         bool "256KiB pages"                   << 
1180         depends on HAVE_PAGE_SIZE_256KB       << 
1181         help                                  << 
1182           256KiB pages have little practical  << 
1183           memory usage.  The kernel will only << 
1184           that have been compiled with '-zmax << 
1185           (the default is 64KiB or 4KiB on mo << 
1186                                               << 
1187 endchoice                                     << 
1188                                               << 
1189 config PAGE_SIZE_LESS_THAN_64KB               << 
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                                                  680 
1234 config HAVE_STACK_VALIDATION                     681 config HAVE_STACK_VALIDATION
1235         bool                                     682         bool
1236         help                                     683         help
1237           Architecture supports objtool compi !! 684           Architecture supports the 'objtool check' host tool command, which
1238           validation.                         !! 685           performs compile-time stack metadata validation.
1239                                               << 
1240 config HAVE_RELIABLE_STACKTRACE               << 
1241         bool                                  << 
1242         help                                  << 
1243           Architecture has either save_stack_ << 
1244           arch_stack_walk_reliable() function << 
1245           if it can guarantee the trace is re << 
1246                                                  686 
1247 config HAVE_ARCH_HASH                            687 config HAVE_ARCH_HASH
1248         bool                                     688         bool
1249         default n                                689         default n
1250         help                                     690         help
1251           If this is set, the architecture pr    691           If this is set, the architecture provides an <asm/hash.h>
1252           file which provides platform-specif    692           file which provides platform-specific implementations of some
1253           functions in <linux/hash.h> or fs/n    693           functions in <linux/hash.h> or fs/namei.c.
1254                                                  694 
1255 config HAVE_ARCH_NVRAM_OPS                    << 
1256         bool                                  << 
1257                                               << 
1258 config ISA_BUS_API                               695 config ISA_BUS_API
1259         def_bool ISA                             696         def_bool ISA
1260                                                  697 
1261 #                                                698 #
1262 # ABI hall of shame                              699 # ABI hall of shame
1263 #                                                700 #
1264 config CLONE_BACKWARDS                           701 config CLONE_BACKWARDS
1265         bool                                     702         bool
1266         help                                     703         help
1267           Architecture has tls passed as the     704           Architecture has tls passed as the 4th argument of clone(2),
1268           not the 5th one.                       705           not the 5th one.
1269                                                  706 
1270 config CLONE_BACKWARDS2                          707 config CLONE_BACKWARDS2
1271         bool                                     708         bool
1272         help                                     709         help
1273           Architecture has the first two argu    710           Architecture has the first two arguments of clone(2) swapped.
1274                                                  711 
1275 config CLONE_BACKWARDS3                          712 config CLONE_BACKWARDS3
1276         bool                                     713         bool
1277         help                                     714         help
1278           Architecture has tls passed as the     715           Architecture has tls passed as the 3rd argument of clone(2),
1279           not the 5th one.                       716           not the 5th one.
1280                                                  717 
1281 config ODD_RT_SIGACTION                          718 config ODD_RT_SIGACTION
1282         bool                                     719         bool
1283         help                                     720         help
1284           Architecture has unusual rt_sigacti    721           Architecture has unusual rt_sigaction(2) arguments
1285                                                  722 
1286 config OLD_SIGSUSPEND                            723 config OLD_SIGSUSPEND
1287         bool                                     724         bool
1288         help                                     725         help
1289           Architecture has old sigsuspend(2)     726           Architecture has old sigsuspend(2) syscall, of one-argument variety
1290                                                  727 
1291 config OLD_SIGSUSPEND3                           728 config OLD_SIGSUSPEND3
1292         bool                                     729         bool
1293         help                                     730         help
1294           Even weirder antique ABI - three-ar    731           Even weirder antique ABI - three-argument sigsuspend(2)
1295                                                  732 
1296 config OLD_SIGACTION                             733 config OLD_SIGACTION
1297         bool                                     734         bool
1298         help                                     735         help
1299           Architecture has old sigaction(2) s    736           Architecture has old sigaction(2) syscall.  Nope, not the same
1300           as OLD_SIGSUSPEND | OLD_SIGSUSPEND3    737           as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
1301           but fairly different variant of sig    738           but fairly different variant of sigaction(2), thanks to OSF/1
1302           compatibility...                       739           compatibility...
1303                                                  740 
1304 config COMPAT_OLD_SIGACTION                      741 config COMPAT_OLD_SIGACTION
1305         bool                                     742         bool
1306                                                  743 
1307 config COMPAT_32BIT_TIME                      !! 744 config ARCH_NO_COHERENT_DMA_MMAP
1308         bool "Provide system calls for 32-bit << 
1309         default !64BIT || COMPAT              << 
1310         help                                  << 
1311           This enables 32 bit time_t support  << 
1312           This is relevant on all 32-bit arch << 
1313           as part of compat syscall handling. << 
1314                                               << 
1315 config ARCH_NO_PREEMPT                        << 
1316         bool                                  << 
1317                                               << 
1318 config ARCH_SUPPORTS_RT                       << 
1319         bool                                     745         bool
1320                                                  746 
1321 config CPU_NO_EFFICIENT_FFS                      747 config CPU_NO_EFFICIENT_FFS
1322         def_bool n                               748         def_bool n
1323                                                  749 
1324 config HAVE_ARCH_VMAP_STACK                      750 config HAVE_ARCH_VMAP_STACK
1325         def_bool n                               751         def_bool n
1326         help                                     752         help
1327           An arch should select this symbol i    753           An arch should select this symbol if it can support kernel stacks
1328           in vmalloc space.  This means:         754           in vmalloc space.  This means:
1329                                                  755 
1330           - vmalloc space must be large enoug    756           - vmalloc space must be large enough to hold many kernel stacks.
1331             This may rule out many 32-bit arc    757             This may rule out many 32-bit architectures.
1332                                                  758 
1333           - Stacks in vmalloc space need to w    759           - Stacks in vmalloc space need to work reliably.  For example, if
1334             vmap page tables are created on d    760             vmap page tables are created on demand, either this mechanism
1335             needs to work while the stack poi    761             needs to work while the stack points to a virtual address with
1336             unpopulated page tables or arch c    762             unpopulated page tables or arch code (switch_to() and switch_mm(),
1337             most likely) needs to ensure that    763             most likely) needs to ensure that the stack's page table entries
1338             are populated before running on a    764             are populated before running on a possibly unpopulated stack.
1339                                                  765 
1340           - If the stack overflows into a gua    766           - If the stack overflows into a guard page, something reasonable
1341             should happen.  The definition of    767             should happen.  The definition of "reasonable" is flexible, but
1342             instantly rebooting without loggi    768             instantly rebooting without logging anything would be unfriendly.
1343                                                  769 
1344 config VMAP_STACK                                770 config VMAP_STACK
1345         default y                                771         default y
1346         bool "Use a virtually-mapped stack"      772         bool "Use a virtually-mapped stack"
1347         depends on HAVE_ARCH_VMAP_STACK       !! 773         depends on HAVE_ARCH_VMAP_STACK && !KASAN
1348         depends on !KASAN || KASAN_HW_TAGS || !! 774         ---help---
1349         help                                  << 
1350           Enable this if you want the use vir    775           Enable this if you want the use virtually-mapped kernel stacks
1351           with guard pages.  This causes kern    776           with guard pages.  This causes kernel stack overflows to be
1352           caught immediately rather than caus    777           caught immediately rather than causing difficult-to-diagnose
1353           corruption.                            778           corruption.
1354                                                  779 
1355           To use this with software KASAN mod !! 780           This is presently incompatible with KASAN because KASAN expects
1356           backing virtual mappings with real  !! 781           the stack to map directly to the KASAN shadow map using a formula
1357           must be enabled.                    !! 782           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                                               << 
1396 config ARCH_OPTIONAL_KERNEL_RWX               << 
1397         def_bool n                            << 
1398                                               << 
1399 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT       << 
1400         def_bool n                            << 
1401                                               << 
1402 config ARCH_HAS_STRICT_KERNEL_RWX             << 
1403         def_bool n                            << 
1404                                               << 
1405 config STRICT_KERNEL_RWX                      << 
1406         bool "Make kernel text and rodata rea << 
1407         depends on ARCH_HAS_STRICT_KERNEL_RWX << 
1408         default !ARCH_OPTIONAL_KERNEL_RWX ||  << 
1409         help                                  << 
1410           If this is set, kernel text and rod << 
1411           and non-text memory will be made no << 
1412           protection against certain security << 
1413           or modifying text)                  << 
1414                                               << 
1415           These features are considered stand << 
1416           You should say Y here in almost all << 
1417                                               << 
1418 config ARCH_HAS_STRICT_MODULE_RWX             << 
1419         def_bool n                            << 
1420                                               << 
1421 config STRICT_MODULE_RWX                      << 
1422         bool "Set loadable kernel module data << 
1423         depends on ARCH_HAS_STRICT_MODULE_RWX << 
1424         default !ARCH_OPTIONAL_KERNEL_RWX ||  << 
1425         help                                  << 
1426           If this is set, module text and rod << 
1427           and non-text memory will be made no << 
1428           protection against certain security << 
1429                                               << 
1430 # select if the architecture provides an asm/ << 
1431 config ARCH_HAS_PHYS_TO_DMA                   << 
1432         bool                                  << 
1433                                               << 
1434 config HAVE_ARCH_COMPILER_H                   << 
1435         bool                                  << 
1436         help                                  << 
1437           An architecture can select this if  << 
1438           asm/compiler.h header that should b << 
1439           linux/compiler-*.h in order to over << 
1440           headers generally provide.          << 
1441                                               << 
1442 config HAVE_ARCH_PREL32_RELOCATIONS           << 
1443         bool                                  << 
1444         help                                  << 
1445           May be selected by an architecture  << 
1446           32-bit relocations, both in the too << 
1447           in which case relative references c << 
1448           for PCI fixup, initcalls etc which  << 
1449           architectures, and don't require ru << 
1450           kernels.                            << 
1451                                               << 
1452 config ARCH_USE_MEMREMAP_PROT                 << 
1453         bool                                  << 
1454                                               << 
1455 config LOCK_EVENT_COUNTS                      << 
1456         bool "Locking event counts collection << 
1457         depends on DEBUG_FS                   << 
1458         help                                  << 
1459           Enable light-weight counting of var << 
1460           in the system with minimal performa << 
1461           the chance of application behavior  << 
1462           differences. The counts are reporte << 
1463                                               << 
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                                                  783 
1603 source "kernel/gcov/Kconfig"                     784 source "kernel/gcov/Kconfig"
1604                                               << 
1605 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                                               << 
1646 endmenu                                       << 
                                                      

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