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b2441318 | 1 | # SPDX-License-Identifier: GPL-2.0 |
fb32e03f MD |
2 | # |
3 | # General architecture dependent options | |
4 | # | |
125e5645 | 5 | |
1572497c CH |
6 | # |
7 | # Note: arch/$(SRCARCH)/Kconfig needs to be included first so that it can | |
8 | # override the default values in this file. | |
9 | # | |
10 | source "arch/$(SRCARCH)/Kconfig" | |
11 | ||
22471e13 RD |
12 | menu "General architecture-dependent options" |
13 | ||
692f66f2 HB |
14 | config CRASH_CORE |
15 | bool | |
16 | ||
2965faa5 | 17 | config KEXEC_CORE |
692f66f2 | 18 | select CRASH_CORE |
2965faa5 DY |
19 | bool |
20 | ||
467d2782 TJB |
21 | config HAVE_IMA_KEXEC |
22 | bool | |
23 | ||
05736e4a TG |
24 | config HOTPLUG_SMT |
25 | bool | |
26 | ||
125e5645 | 27 | config OPROFILE |
b309a294 | 28 | tristate "OProfile system profiling" |
125e5645 MD |
29 | depends on PROFILING |
30 | depends on HAVE_OPROFILE | |
d69d59f4 | 31 | select RING_BUFFER |
9a5963eb | 32 | select RING_BUFFER_ALLOW_SWAP |
125e5645 MD |
33 | help |
34 | OProfile is a profiling system capable of profiling the | |
35 | whole system, include the kernel, kernel modules, libraries, | |
36 | and applications. | |
37 | ||
38 | If unsure, say N. | |
39 | ||
4d4036e0 JY |
40 | config OPROFILE_EVENT_MULTIPLEX |
41 | bool "OProfile multiplexing support (EXPERIMENTAL)" | |
42 | default n | |
43 | depends on OPROFILE && X86 | |
44 | help | |
45 | The number of hardware counters is limited. The multiplexing | |
46 | feature enables OProfile to gather more events than counters | |
47 | are provided by the hardware. This is realized by switching | |
9332ef9d | 48 | between events at a user specified time interval. |
4d4036e0 JY |
49 | |
50 | If unsure, say N. | |
51 | ||
125e5645 | 52 | config HAVE_OPROFILE |
9ba16087 | 53 | bool |
125e5645 | 54 | |
dcfce4a0 RR |
55 | config OPROFILE_NMI_TIMER |
56 | def_bool y | |
af9feebe | 57 | depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64 |
dcfce4a0 | 58 | |
125e5645 MD |
59 | config KPROBES |
60 | bool "Kprobes" | |
05ed160e | 61 | depends on MODULES |
125e5645 | 62 | depends on HAVE_KPROBES |
05ed160e | 63 | select KALLSYMS |
125e5645 MD |
64 | help |
65 | Kprobes allows you to trap at almost any kernel address and | |
66 | execute a callback function. register_kprobe() establishes | |
67 | a probepoint and specifies the callback. Kprobes is useful | |
68 | for kernel debugging, non-intrusive instrumentation and testing. | |
69 | If in doubt, say "N". | |
70 | ||
45f81b1c | 71 | config JUMP_LABEL |
c5905afb | 72 | bool "Optimize very unlikely/likely branches" |
45f81b1c | 73 | depends on HAVE_ARCH_JUMP_LABEL |
e9666d10 | 74 | depends on CC_HAS_ASM_GOTO |
45f81b1c | 75 | help |
c5905afb IM |
76 | This option enables a transparent branch optimization that |
77 | makes certain almost-always-true or almost-always-false branch | |
78 | conditions even cheaper to execute within the kernel. | |
79 | ||
80 | Certain performance-sensitive kernel code, such as trace points, | |
81 | scheduler functionality, networking code and KVM have such | |
82 | branches and include support for this optimization technique. | |
83 | ||
45f81b1c | 84 | If it is detected that the compiler has support for "asm goto", |
c5905afb IM |
85 | the kernel will compile such branches with just a nop |
86 | instruction. When the condition flag is toggled to true, the | |
87 | nop will be converted to a jump instruction to execute the | |
88 | conditional block of instructions. | |
89 | ||
90 | This technique lowers overhead and stress on the branch prediction | |
91 | of the processor and generally makes the kernel faster. The update | |
92 | of the condition is slower, but those are always very rare. | |
45f81b1c | 93 | |
c5905afb IM |
94 | ( On 32-bit x86, the necessary options added to the compiler |
95 | flags may increase the size of the kernel slightly. ) | |
45f81b1c | 96 | |
1987c947 PZ |
97 | config STATIC_KEYS_SELFTEST |
98 | bool "Static key selftest" | |
99 | depends on JUMP_LABEL | |
100 | help | |
101 | Boot time self-test of the branch patching code. | |
102 | ||
afd66255 | 103 | config OPTPROBES |
5cc718b9 MH |
104 | def_bool y |
105 | depends on KPROBES && HAVE_OPTPROBES | |
a30b85df | 106 | select TASKS_RCU if PREEMPT |
afd66255 | 107 | |
e7dbfe34 MH |
108 | config KPROBES_ON_FTRACE |
109 | def_bool y | |
110 | depends on KPROBES && HAVE_KPROBES_ON_FTRACE | |
111 | depends on DYNAMIC_FTRACE_WITH_REGS | |
112 | help | |
113 | If function tracer is enabled and the arch supports full | |
114 | passing of pt_regs to function tracing, then kprobes can | |
115 | optimize on top of function tracing. | |
116 | ||
2b144498 | 117 | config UPROBES |
09294e31 | 118 | def_bool n |
e8f4aa60 | 119 | depends on ARCH_SUPPORTS_UPROBES |
2b144498 | 120 | help |
7b2d81d4 IM |
121 | Uprobes is the user-space counterpart to kprobes: they |
122 | enable instrumentation applications (such as 'perf probe') | |
123 | to establish unintrusive probes in user-space binaries and | |
124 | libraries, by executing handler functions when the probes | |
125 | are hit by user-space applications. | |
126 | ||
127 | ( These probes come in the form of single-byte breakpoints, | |
128 | managed by the kernel and kept transparent to the probed | |
129 | application. ) | |
2b144498 | 130 | |
c19fa94a JH |
131 | config HAVE_64BIT_ALIGNED_ACCESS |
132 | def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS | |
133 | help | |
134 | Some architectures require 64 bit accesses to be 64 bit | |
135 | aligned, which also requires structs containing 64 bit values | |
136 | to be 64 bit aligned too. This includes some 32 bit | |
137 | architectures which can do 64 bit accesses, as well as 64 bit | |
138 | architectures without unaligned access. | |
139 | ||
140 | This symbol should be selected by an architecture if 64 bit | |
141 | accesses are required to be 64 bit aligned in this way even | |
142 | though it is not a 64 bit architecture. | |
143 | ||
144 | See Documentation/unaligned-memory-access.txt for more | |
145 | information on the topic of unaligned memory accesses. | |
146 | ||
58340a07 | 147 | config HAVE_EFFICIENT_UNALIGNED_ACCESS |
9ba16087 | 148 | bool |
58340a07 JB |
149 | help |
150 | Some architectures are unable to perform unaligned accesses | |
151 | without the use of get_unaligned/put_unaligned. Others are | |
152 | unable to perform such accesses efficiently (e.g. trap on | |
153 | unaligned access and require fixing it up in the exception | |
154 | handler.) | |
155 | ||
156 | This symbol should be selected by an architecture if it can | |
157 | perform unaligned accesses efficiently to allow different | |
158 | code paths to be selected for these cases. Some network | |
159 | drivers, for example, could opt to not fix up alignment | |
160 | problems with received packets if doing so would not help | |
161 | much. | |
162 | ||
163 | See Documentation/unaligned-memory-access.txt for more | |
164 | information on the topic of unaligned memory accesses. | |
165 | ||
cf66bb93 DW |
166 | config ARCH_USE_BUILTIN_BSWAP |
167 | bool | |
168 | help | |
169 | Modern versions of GCC (since 4.4) have builtin functions | |
170 | for handling byte-swapping. Using these, instead of the old | |
171 | inline assembler that the architecture code provides in the | |
172 | __arch_bswapXX() macros, allows the compiler to see what's | |
173 | happening and offers more opportunity for optimisation. In | |
174 | particular, the compiler will be able to combine the byteswap | |
175 | with a nearby load or store and use load-and-swap or | |
176 | store-and-swap instructions if the architecture has them. It | |
177 | should almost *never* result in code which is worse than the | |
178 | hand-coded assembler in <asm/swab.h>. But just in case it | |
179 | does, the use of the builtins is optional. | |
180 | ||
181 | Any architecture with load-and-swap or store-and-swap | |
182 | instructions should set this. And it shouldn't hurt to set it | |
183 | on architectures that don't have such instructions. | |
184 | ||
9edddaa2 AM |
185 | config KRETPROBES |
186 | def_bool y | |
187 | depends on KPROBES && HAVE_KRETPROBES | |
188 | ||
7c68af6e AK |
189 | config USER_RETURN_NOTIFIER |
190 | bool | |
191 | depends on HAVE_USER_RETURN_NOTIFIER | |
192 | help | |
193 | Provide a kernel-internal notification when a cpu is about to | |
194 | switch to user mode. | |
195 | ||
28b2ee20 | 196 | config HAVE_IOREMAP_PROT |
9ba16087 | 197 | bool |
28b2ee20 | 198 | |
125e5645 | 199 | config HAVE_KPROBES |
9ba16087 | 200 | bool |
9edddaa2 AM |
201 | |
202 | config HAVE_KRETPROBES | |
9ba16087 | 203 | bool |
74bc7cee | 204 | |
afd66255 MH |
205 | config HAVE_OPTPROBES |
206 | bool | |
d314d74c | 207 | |
e7dbfe34 MH |
208 | config HAVE_KPROBES_ON_FTRACE |
209 | bool | |
210 | ||
540adea3 | 211 | config HAVE_FUNCTION_ERROR_INJECTION |
9802d865 JB |
212 | bool |
213 | ||
42a0bb3f PM |
214 | config HAVE_NMI |
215 | bool | |
216 | ||
1f5a4ad9 RM |
217 | # |
218 | # An arch should select this if it provides all these things: | |
219 | # | |
220 | # task_pt_regs() in asm/processor.h or asm/ptrace.h | |
221 | # arch_has_single_step() if there is hardware single-step support | |
222 | # arch_has_block_step() if there is hardware block-step support | |
1f5a4ad9 RM |
223 | # asm/syscall.h supplying asm-generic/syscall.h interface |
224 | # linux/regset.h user_regset interfaces | |
225 | # CORE_DUMP_USE_REGSET #define'd in linux/elf.h | |
226 | # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} | |
227 | # TIF_NOTIFY_RESUME calls tracehook_notify_resume() | |
228 | # signal delivery calls tracehook_signal_handler() | |
229 | # | |
230 | config HAVE_ARCH_TRACEHOOK | |
9ba16087 | 231 | bool |
1f5a4ad9 | 232 | |
c64be2bb MS |
233 | config HAVE_DMA_CONTIGUOUS |
234 | bool | |
235 | ||
29d5e047 TG |
236 | config GENERIC_SMP_IDLE_THREAD |
237 | bool | |
238 | ||
485cf5da KH |
239 | config GENERIC_IDLE_POLL_SETUP |
240 | bool | |
241 | ||
6974f0c4 DM |
242 | config ARCH_HAS_FORTIFY_SOURCE |
243 | bool | |
244 | help | |
245 | An architecture should select this when it can successfully | |
246 | build and run with CONFIG_FORTIFY_SOURCE. | |
247 | ||
d8ae8a37 CH |
248 | # |
249 | # Select if the arch provides a historic keepinit alias for the retain_initrd | |
250 | # command line option | |
251 | # | |
252 | config ARCH_HAS_KEEPINITRD | |
253 | bool | |
254 | ||
d2852a22 DB |
255 | # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h |
256 | config ARCH_HAS_SET_MEMORY | |
257 | bool | |
258 | ||
d253ca0c RE |
259 | # Select if arch has all set_direct_map_invalid/default() functions |
260 | config ARCH_HAS_SET_DIRECT_MAP | |
261 | bool | |
262 | ||
0500871f DH |
263 | # Select if arch init_task must go in the __init_task_data section |
264 | config ARCH_TASK_STRUCT_ON_STACK | |
a4a2eb49 TG |
265 | bool |
266 | ||
f5e10287 TG |
267 | # Select if arch has its private alloc_task_struct() function |
268 | config ARCH_TASK_STRUCT_ALLOCATOR | |
269 | bool | |
270 | ||
5905429a KC |
271 | config HAVE_ARCH_THREAD_STRUCT_WHITELIST |
272 | bool | |
273 | depends on !ARCH_TASK_STRUCT_ALLOCATOR | |
274 | help | |
275 | An architecture should select this to provide hardened usercopy | |
276 | knowledge about what region of the thread_struct should be | |
277 | whitelisted for copying to userspace. Normally this is only the | |
278 | FPU registers. Specifically, arch_thread_struct_whitelist() | |
279 | should be implemented. Without this, the entire thread_struct | |
280 | field in task_struct will be left whitelisted. | |
281 | ||
b235beea LT |
282 | # Select if arch has its private alloc_thread_stack() function |
283 | config ARCH_THREAD_STACK_ALLOCATOR | |
f5e10287 TG |
284 | bool |
285 | ||
5aaeb5c0 IM |
286 | # Select if arch wants to size task_struct dynamically via arch_task_struct_size: |
287 | config ARCH_WANTS_DYNAMIC_TASK_STRUCT | |
288 | bool | |
289 | ||
942fa985 YN |
290 | config ARCH_32BIT_OFF_T |
291 | bool | |
292 | depends on !64BIT | |
293 | help | |
294 | All new 32-bit architectures should have 64-bit off_t type on | |
295 | userspace side which corresponds to the loff_t kernel type. This | |
296 | is the requirement for modern ABIs. Some existing architectures | |
297 | still support 32-bit off_t. This option is enabled for all such | |
298 | architectures explicitly. | |
299 | ||
f850c30c HC |
300 | config HAVE_REGS_AND_STACK_ACCESS_API |
301 | bool | |
e01292b1 HC |
302 | help |
303 | This symbol should be selected by an architecure if it supports | |
304 | the API needed to access registers and stack entries from pt_regs, | |
305 | declared in asm/ptrace.h | |
306 | For example the kprobes-based event tracer needs this API. | |
f850c30c | 307 | |
d7822b1e MD |
308 | config HAVE_RSEQ |
309 | bool | |
310 | depends on HAVE_REGS_AND_STACK_ACCESS_API | |
311 | help | |
312 | This symbol should be selected by an architecture if it | |
313 | supports an implementation of restartable sequences. | |
314 | ||
3c88ee19 MH |
315 | config HAVE_FUNCTION_ARG_ACCESS_API |
316 | bool | |
317 | help | |
318 | This symbol should be selected by an architecure if it supports | |
319 | the API needed to access function arguments from pt_regs, | |
320 | declared in asm/ptrace.h | |
321 | ||
9483a578 | 322 | config HAVE_CLK |
9ba16087 | 323 | bool |
9483a578 DB |
324 | help |
325 | The <linux/clk.h> calls support software clock gating and | |
326 | thus are a key power management tool on many systems. | |
327 | ||
62a038d3 P |
328 | config HAVE_HW_BREAKPOINT |
329 | bool | |
99e8c5a3 | 330 | depends on PERF_EVENTS |
62a038d3 | 331 | |
0102752e FW |
332 | config HAVE_MIXED_BREAKPOINTS_REGS |
333 | bool | |
334 | depends on HAVE_HW_BREAKPOINT | |
335 | help | |
336 | Depending on the arch implementation of hardware breakpoints, | |
337 | some of them have separate registers for data and instruction | |
338 | breakpoints addresses, others have mixed registers to store | |
339 | them but define the access type in a control register. | |
340 | Select this option if your arch implements breakpoints under the | |
341 | latter fashion. | |
342 | ||
7c68af6e AK |
343 | config HAVE_USER_RETURN_NOTIFIER |
344 | bool | |
a1922ed6 | 345 | |
c01d4323 FW |
346 | config HAVE_PERF_EVENTS_NMI |
347 | bool | |
23637d47 FW |
348 | help |
349 | System hardware can generate an NMI using the perf event | |
350 | subsystem. Also has support for calculating CPU cycle events | |
351 | to determine how many clock cycles in a given period. | |
c01d4323 | 352 | |
05a4a952 NP |
353 | config HAVE_HARDLOCKUP_DETECTOR_PERF |
354 | bool | |
355 | depends on HAVE_PERF_EVENTS_NMI | |
356 | help | |
357 | The arch chooses to use the generic perf-NMI-based hardlockup | |
358 | detector. Must define HAVE_PERF_EVENTS_NMI. | |
359 | ||
360 | config HAVE_NMI_WATCHDOG | |
361 | depends on HAVE_NMI | |
362 | bool | |
363 | help | |
364 | The arch provides a low level NMI watchdog. It provides | |
365 | asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). | |
366 | ||
367 | config HAVE_HARDLOCKUP_DETECTOR_ARCH | |
368 | bool | |
369 | select HAVE_NMI_WATCHDOG | |
370 | help | |
371 | The arch chooses to provide its own hardlockup detector, which is | |
372 | a superset of the HAVE_NMI_WATCHDOG. It also conforms to config | |
373 | interfaces and parameters provided by hardlockup detector subsystem. | |
374 | ||
c5e63197 JO |
375 | config HAVE_PERF_REGS |
376 | bool | |
377 | help | |
378 | Support selective register dumps for perf events. This includes | |
379 | bit-mapping of each registers and a unique architecture id. | |
380 | ||
c5ebcedb JO |
381 | config HAVE_PERF_USER_STACK_DUMP |
382 | bool | |
383 | help | |
384 | Support user stack dumps for perf event samples. This needs | |
385 | access to the user stack pointer which is not unified across | |
386 | architectures. | |
387 | ||
bf5438fc JB |
388 | config HAVE_ARCH_JUMP_LABEL |
389 | bool | |
390 | ||
50ff18ab AB |
391 | config HAVE_ARCH_JUMP_LABEL_RELATIVE |
392 | bool | |
393 | ||
26723911 PZ |
394 | config HAVE_RCU_TABLE_FREE |
395 | bool | |
396 | ||
96bc9567 | 397 | config HAVE_RCU_TABLE_NO_INVALIDATE |
d86564a2 PZ |
398 | bool |
399 | ||
ed6a7935 PZ |
400 | config HAVE_MMU_GATHER_PAGE_SIZE |
401 | bool | |
402 | ||
952a31c9 MS |
403 | config HAVE_MMU_GATHER_NO_GATHER |
404 | bool | |
405 | ||
df013ffb HY |
406 | config ARCH_HAVE_NMI_SAFE_CMPXCHG |
407 | bool | |
408 | ||
43570fd2 HC |
409 | config HAVE_ALIGNED_STRUCT_PAGE |
410 | bool | |
411 | help | |
412 | This makes sure that struct pages are double word aligned and that | |
413 | e.g. the SLUB allocator can perform double word atomic operations | |
414 | on a struct page for better performance. However selecting this | |
415 | might increase the size of a struct page by a word. | |
416 | ||
4156153c HC |
417 | config HAVE_CMPXCHG_LOCAL |
418 | bool | |
419 | ||
2565409f HC |
420 | config HAVE_CMPXCHG_DOUBLE |
421 | bool | |
422 | ||
77e58496 PM |
423 | config ARCH_WEAK_RELEASE_ACQUIRE |
424 | bool | |
425 | ||
c1d7e01d WD |
426 | config ARCH_WANT_IPC_PARSE_VERSION |
427 | bool | |
428 | ||
429 | config ARCH_WANT_COMPAT_IPC_PARSE_VERSION | |
430 | bool | |
431 | ||
48b25c43 | 432 | config ARCH_WANT_OLD_COMPAT_IPC |
c1d7e01d | 433 | select ARCH_WANT_COMPAT_IPC_PARSE_VERSION |
48b25c43 CM |
434 | bool |
435 | ||
e2cfabdf WD |
436 | config HAVE_ARCH_SECCOMP_FILTER |
437 | bool | |
438 | help | |
fb0fadf9 | 439 | An arch should select this symbol if it provides all of these things: |
bb6ea430 WD |
440 | - syscall_get_arch() |
441 | - syscall_get_arguments() | |
442 | - syscall_rollback() | |
443 | - syscall_set_return_value() | |
fb0fadf9 WD |
444 | - SIGSYS siginfo_t support |
445 | - secure_computing is called from a ptrace_event()-safe context | |
446 | - secure_computing return value is checked and a return value of -1 | |
447 | results in the system call being skipped immediately. | |
48dc92b9 | 448 | - seccomp syscall wired up |
e2cfabdf WD |
449 | |
450 | config SECCOMP_FILTER | |
451 | def_bool y | |
452 | depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET | |
453 | help | |
454 | Enable tasks to build secure computing environments defined | |
455 | in terms of Berkeley Packet Filter programs which implement | |
456 | task-defined system call filtering polices. | |
457 | ||
5fb94e9c | 458 | See Documentation/userspace-api/seccomp_filter.rst for details. |
e2cfabdf | 459 | |
afaef01c AP |
460 | config HAVE_ARCH_STACKLEAK |
461 | bool | |
462 | help | |
463 | An architecture should select this if it has the code which | |
464 | fills the used part of the kernel stack with the STACKLEAK_POISON | |
465 | value before returning from system calls. | |
466 | ||
d148eac0 | 467 | config HAVE_STACKPROTECTOR |
19952a92 KC |
468 | bool |
469 | help | |
470 | An arch should select this symbol if: | |
19952a92 KC |
471 | - it has implemented a stack canary (e.g. __stack_chk_guard) |
472 | ||
2a61f474 MY |
473 | config CC_HAS_STACKPROTECTOR_NONE |
474 | def_bool $(cc-option,-fno-stack-protector) | |
475 | ||
050e9baa | 476 | config STACKPROTECTOR |
2a61f474 | 477 | bool "Stack Protector buffer overflow detection" |
d148eac0 | 478 | depends on HAVE_STACKPROTECTOR |
2a61f474 MY |
479 | depends on $(cc-option,-fstack-protector) |
480 | default y | |
19952a92 | 481 | help |
8779657d | 482 | This option turns on the "stack-protector" GCC feature. This |
19952a92 KC |
483 | feature puts, at the beginning of functions, a canary value on |
484 | the stack just before the return address, and validates | |
485 | the value just before actually returning. Stack based buffer | |
486 | overflows (that need to overwrite this return address) now also | |
487 | overwrite the canary, which gets detected and the attack is then | |
488 | neutralized via a kernel panic. | |
489 | ||
8779657d KC |
490 | Functions will have the stack-protector canary logic added if they |
491 | have an 8-byte or larger character array on the stack. | |
492 | ||
19952a92 | 493 | This feature requires gcc version 4.2 or above, or a distribution |
8779657d KC |
494 | gcc with the feature backported ("-fstack-protector"). |
495 | ||
496 | On an x86 "defconfig" build, this feature adds canary checks to | |
497 | about 3% of all kernel functions, which increases kernel code size | |
498 | by about 0.3%. | |
499 | ||
050e9baa | 500 | config STACKPROTECTOR_STRONG |
2a61f474 | 501 | bool "Strong Stack Protector" |
050e9baa | 502 | depends on STACKPROTECTOR |
2a61f474 MY |
503 | depends on $(cc-option,-fstack-protector-strong) |
504 | default y | |
8779657d KC |
505 | help |
506 | Functions will have the stack-protector canary logic added in any | |
507 | of the following conditions: | |
508 | ||
509 | - local variable's address used as part of the right hand side of an | |
510 | assignment or function argument | |
511 | - local variable is an array (or union containing an array), | |
512 | regardless of array type or length | |
513 | - uses register local variables | |
514 | ||
515 | This feature requires gcc version 4.9 or above, or a distribution | |
516 | gcc with the feature backported ("-fstack-protector-strong"). | |
517 | ||
518 | On an x86 "defconfig" build, this feature adds canary checks to | |
519 | about 20% of all kernel functions, which increases the kernel code | |
520 | size by about 2%. | |
521 | ||
0f60a8ef KC |
522 | config HAVE_ARCH_WITHIN_STACK_FRAMES |
523 | bool | |
524 | help | |
525 | An architecture should select this if it can walk the kernel stack | |
526 | frames to determine if an object is part of either the arguments | |
527 | or local variables (i.e. that it excludes saved return addresses, | |
528 | and similar) by implementing an inline arch_within_stack_frames(), | |
529 | which is used by CONFIG_HARDENED_USERCOPY. | |
530 | ||
91d1aa43 | 531 | config HAVE_CONTEXT_TRACKING |
2b1d5024 FW |
532 | bool |
533 | help | |
91d1aa43 FW |
534 | Provide kernel/user boundaries probes necessary for subsystems |
535 | that need it, such as userspace RCU extended quiescent state. | |
536 | Syscalls need to be wrapped inside user_exit()-user_enter() through | |
537 | the slow path using TIF_NOHZ flag. Exceptions handlers must be | |
538 | wrapped as well. Irqs are already protected inside | |
539 | rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on | |
540 | irq exit still need to be protected. | |
2b1d5024 | 541 | |
b952741c FW |
542 | config HAVE_VIRT_CPU_ACCOUNTING |
543 | bool | |
544 | ||
40565b5a SG |
545 | config ARCH_HAS_SCALED_CPUTIME |
546 | bool | |
547 | ||
554b0004 KH |
548 | config HAVE_VIRT_CPU_ACCOUNTING_GEN |
549 | bool | |
550 | default y if 64BIT | |
551 | help | |
552 | With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. | |
553 | Before enabling this option, arch code must be audited | |
554 | to ensure there are no races in concurrent read/write of | |
555 | cputime_t. For example, reading/writing 64-bit cputime_t on | |
556 | some 32-bit arches may require multiple accesses, so proper | |
557 | locking is needed to protect against concurrent accesses. | |
558 | ||
559 | ||
fdf9c356 FW |
560 | config HAVE_IRQ_TIME_ACCOUNTING |
561 | bool | |
562 | help | |
563 | Archs need to ensure they use a high enough resolution clock to | |
564 | support irq time accounting and then call enable_sched_clock_irqtime(). | |
565 | ||
2c91bd4a JFG |
566 | config HAVE_MOVE_PMD |
567 | bool | |
568 | help | |
569 | Archs that select this are able to move page tables at the PMD level. | |
570 | ||
15626062 GS |
571 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE |
572 | bool | |
573 | ||
a00cc7d9 MW |
574 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
575 | bool | |
576 | ||
0ddab1d2 TK |
577 | config HAVE_ARCH_HUGE_VMAP |
578 | bool | |
579 | ||
0f8975ec PE |
580 | config HAVE_ARCH_SOFT_DIRTY |
581 | bool | |
582 | ||
786d35d4 DH |
583 | config HAVE_MOD_ARCH_SPECIFIC |
584 | bool | |
585 | help | |
586 | The arch uses struct mod_arch_specific to store data. Many arches | |
587 | just need a simple module loader without arch specific data - those | |
588 | should not enable this. | |
589 | ||
590 | config MODULES_USE_ELF_RELA | |
591 | bool | |
592 | help | |
593 | Modules only use ELF RELA relocations. Modules with ELF REL | |
594 | relocations will give an error. | |
595 | ||
596 | config MODULES_USE_ELF_REL | |
597 | bool | |
598 | help | |
599 | Modules only use ELF REL relocations. Modules with ELF RELA | |
600 | relocations will give an error. | |
601 | ||
cc1f0274 FW |
602 | config HAVE_IRQ_EXIT_ON_IRQ_STACK |
603 | bool | |
604 | help | |
605 | Architecture doesn't only execute the irq handler on the irq stack | |
606 | but also irq_exit(). This way we can process softirqs on this irq | |
607 | stack instead of switching to a new one when we call __do_softirq() | |
608 | in the end of an hardirq. | |
609 | This spares a stack switch and improves cache usage on softirq | |
610 | processing. | |
611 | ||
235a8f02 KS |
612 | config PGTABLE_LEVELS |
613 | int | |
614 | default 2 | |
615 | ||
2b68f6ca KC |
616 | config ARCH_HAS_ELF_RANDOMIZE |
617 | bool | |
618 | help | |
619 | An architecture supports choosing randomized locations for | |
620 | stack, mmap, brk, and ET_DYN. Defined functions: | |
621 | - arch_mmap_rnd() | |
204db6ed | 622 | - arch_randomize_brk() |
2b68f6ca | 623 | |
d07e2259 DC |
624 | config HAVE_ARCH_MMAP_RND_BITS |
625 | bool | |
626 | help | |
627 | An arch should select this symbol if it supports setting a variable | |
628 | number of bits for use in establishing the base address for mmap | |
629 | allocations, has MMU enabled and provides values for both: | |
630 | - ARCH_MMAP_RND_BITS_MIN | |
631 | - ARCH_MMAP_RND_BITS_MAX | |
632 | ||
5f56a5df JS |
633 | config HAVE_EXIT_THREAD |
634 | bool | |
635 | help | |
636 | An architecture implements exit_thread. | |
637 | ||
d07e2259 DC |
638 | config ARCH_MMAP_RND_BITS_MIN |
639 | int | |
640 | ||
641 | config ARCH_MMAP_RND_BITS_MAX | |
642 | int | |
643 | ||
644 | config ARCH_MMAP_RND_BITS_DEFAULT | |
645 | int | |
646 | ||
647 | config ARCH_MMAP_RND_BITS | |
648 | int "Number of bits to use for ASLR of mmap base address" if EXPERT | |
649 | range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX | |
650 | default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT | |
651 | default ARCH_MMAP_RND_BITS_MIN | |
652 | depends on HAVE_ARCH_MMAP_RND_BITS | |
653 | help | |
654 | This value can be used to select the number of bits to use to | |
655 | determine the random offset to the base address of vma regions | |
656 | resulting from mmap allocations. This value will be bounded | |
657 | by the architecture's minimum and maximum supported values. | |
658 | ||
659 | This value can be changed after boot using the | |
660 | /proc/sys/vm/mmap_rnd_bits tunable | |
661 | ||
662 | config HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
663 | bool | |
664 | help | |
665 | An arch should select this symbol if it supports running applications | |
666 | in compatibility mode, supports setting a variable number of bits for | |
667 | use in establishing the base address for mmap allocations, has MMU | |
668 | enabled and provides values for both: | |
669 | - ARCH_MMAP_RND_COMPAT_BITS_MIN | |
670 | - ARCH_MMAP_RND_COMPAT_BITS_MAX | |
671 | ||
672 | config ARCH_MMAP_RND_COMPAT_BITS_MIN | |
673 | int | |
674 | ||
675 | config ARCH_MMAP_RND_COMPAT_BITS_MAX | |
676 | int | |
677 | ||
678 | config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
679 | int | |
680 | ||
681 | config ARCH_MMAP_RND_COMPAT_BITS | |
682 | int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT | |
683 | range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX | |
684 | default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
685 | default ARCH_MMAP_RND_COMPAT_BITS_MIN | |
686 | depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
687 | help | |
688 | This value can be used to select the number of bits to use to | |
689 | determine the random offset to the base address of vma regions | |
690 | resulting from mmap allocations for compatible applications This | |
691 | value will be bounded by the architecture's minimum and maximum | |
692 | supported values. | |
693 | ||
694 | This value can be changed after boot using the | |
695 | /proc/sys/vm/mmap_rnd_compat_bits tunable | |
696 | ||
1b028f78 DS |
697 | config HAVE_ARCH_COMPAT_MMAP_BASES |
698 | bool | |
699 | help | |
700 | This allows 64bit applications to invoke 32-bit mmap() syscall | |
701 | and vice-versa 32-bit applications to call 64-bit mmap(). | |
702 | Required for applications doing different bitness syscalls. | |
703 | ||
3033f14a JT |
704 | config HAVE_COPY_THREAD_TLS |
705 | bool | |
706 | help | |
707 | Architecture provides copy_thread_tls to accept tls argument via | |
708 | normal C parameter passing, rather than extracting the syscall | |
709 | argument from pt_regs. | |
710 | ||
b9ab5ebb JP |
711 | config HAVE_STACK_VALIDATION |
712 | bool | |
713 | help | |
714 | Architecture supports the 'objtool check' host tool command, which | |
715 | performs compile-time stack metadata validation. | |
716 | ||
af085d90 JP |
717 | config HAVE_RELIABLE_STACKTRACE |
718 | bool | |
719 | help | |
720 | Architecture has a save_stack_trace_tsk_reliable() function which | |
721 | only returns a stack trace if it can guarantee the trace is reliable. | |
722 | ||
468a9428 GS |
723 | config HAVE_ARCH_HASH |
724 | bool | |
725 | default n | |
726 | help | |
727 | If this is set, the architecture provides an <asm/hash.h> | |
728 | file which provides platform-specific implementations of some | |
729 | functions in <linux/hash.h> or fs/namei.c. | |
730 | ||
666047fe FT |
731 | config HAVE_ARCH_NVRAM_OPS |
732 | bool | |
733 | ||
3a495511 WBG |
734 | config ISA_BUS_API |
735 | def_bool ISA | |
736 | ||
d2125043 AV |
737 | # |
738 | # ABI hall of shame | |
739 | # | |
740 | config CLONE_BACKWARDS | |
741 | bool | |
742 | help | |
743 | Architecture has tls passed as the 4th argument of clone(2), | |
744 | not the 5th one. | |
745 | ||
746 | config CLONE_BACKWARDS2 | |
747 | bool | |
748 | help | |
749 | Architecture has the first two arguments of clone(2) swapped. | |
750 | ||
dfa9771a MS |
751 | config CLONE_BACKWARDS3 |
752 | bool | |
753 | help | |
754 | Architecture has tls passed as the 3rd argument of clone(2), | |
755 | not the 5th one. | |
756 | ||
eaca6eae AV |
757 | config ODD_RT_SIGACTION |
758 | bool | |
759 | help | |
760 | Architecture has unusual rt_sigaction(2) arguments | |
761 | ||
0a0e8cdf AV |
762 | config OLD_SIGSUSPEND |
763 | bool | |
764 | help | |
765 | Architecture has old sigsuspend(2) syscall, of one-argument variety | |
766 | ||
767 | config OLD_SIGSUSPEND3 | |
768 | bool | |
769 | help | |
770 | Even weirder antique ABI - three-argument sigsuspend(2) | |
771 | ||
495dfbf7 AV |
772 | config OLD_SIGACTION |
773 | bool | |
774 | help | |
775 | Architecture has old sigaction(2) syscall. Nope, not the same | |
776 | as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), | |
777 | but fairly different variant of sigaction(2), thanks to OSF/1 | |
778 | compatibility... | |
779 | ||
780 | config COMPAT_OLD_SIGACTION | |
781 | bool | |
782 | ||
d4703dda | 783 | config 64BIT_TIME |
f3d96467 | 784 | def_bool y |
d4703dda DD |
785 | help |
786 | This should be selected by all architectures that need to support | |
787 | new system calls with a 64-bit time_t. This is relevant on all 32-bit | |
788 | architectures, and 64-bit architectures as part of compat syscall | |
789 | handling. | |
790 | ||
17435e5f | 791 | config COMPAT_32BIT_TIME |
00bf25d6 | 792 | def_bool !64BIT || COMPAT |
17435e5f DD |
793 | help |
794 | This enables 32 bit time_t support in addition to 64 bit time_t support. | |
795 | This is relevant on all 32-bit architectures, and 64-bit architectures | |
796 | as part of compat syscall handling. | |
797 | ||
0d4a619b CH |
798 | config ARCH_NO_COHERENT_DMA_MMAP |
799 | bool | |
800 | ||
87a4c375 CH |
801 | config ARCH_NO_PREEMPT |
802 | bool | |
803 | ||
fff7fb0b ZZ |
804 | config CPU_NO_EFFICIENT_FFS |
805 | def_bool n | |
806 | ||
ba14a194 AL |
807 | config HAVE_ARCH_VMAP_STACK |
808 | def_bool n | |
809 | help | |
810 | An arch should select this symbol if it can support kernel stacks | |
811 | in vmalloc space. This means: | |
812 | ||
813 | - vmalloc space must be large enough to hold many kernel stacks. | |
814 | This may rule out many 32-bit architectures. | |
815 | ||
816 | - Stacks in vmalloc space need to work reliably. For example, if | |
817 | vmap page tables are created on demand, either this mechanism | |
818 | needs to work while the stack points to a virtual address with | |
819 | unpopulated page tables or arch code (switch_to() and switch_mm(), | |
820 | most likely) needs to ensure that the stack's page table entries | |
821 | are populated before running on a possibly unpopulated stack. | |
822 | ||
823 | - If the stack overflows into a guard page, something reasonable | |
824 | should happen. The definition of "reasonable" is flexible, but | |
825 | instantly rebooting without logging anything would be unfriendly. | |
826 | ||
827 | config VMAP_STACK | |
828 | default y | |
829 | bool "Use a virtually-mapped stack" | |
830 | depends on HAVE_ARCH_VMAP_STACK && !KASAN | |
831 | ---help--- | |
832 | Enable this if you want the use virtually-mapped kernel stacks | |
833 | with guard pages. This causes kernel stack overflows to be | |
834 | caught immediately rather than causing difficult-to-diagnose | |
835 | corruption. | |
836 | ||
837 | This is presently incompatible with KASAN because KASAN expects | |
838 | the stack to map directly to the KASAN shadow map using a formula | |
839 | that is incorrect if the stack is in vmalloc space. | |
840 | ||
ad21fc4f LA |
841 | config ARCH_OPTIONAL_KERNEL_RWX |
842 | def_bool n | |
843 | ||
844 | config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
845 | def_bool n | |
846 | ||
847 | config ARCH_HAS_STRICT_KERNEL_RWX | |
848 | def_bool n | |
849 | ||
0f5bf6d0 | 850 | config STRICT_KERNEL_RWX |
ad21fc4f LA |
851 | bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX |
852 | depends on ARCH_HAS_STRICT_KERNEL_RWX | |
853 | default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
854 | help | |
855 | If this is set, kernel text and rodata memory will be made read-only, | |
856 | and non-text memory will be made non-executable. This provides | |
857 | protection against certain security exploits (e.g. executing the heap | |
858 | or modifying text) | |
859 | ||
860 | These features are considered standard security practice these days. | |
861 | You should say Y here in almost all cases. | |
862 | ||
863 | config ARCH_HAS_STRICT_MODULE_RWX | |
864 | def_bool n | |
865 | ||
0f5bf6d0 | 866 | config STRICT_MODULE_RWX |
ad21fc4f LA |
867 | bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX |
868 | depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES | |
869 | default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
870 | help | |
871 | If this is set, module text and rodata memory will be made read-only, | |
872 | and non-text memory will be made non-executable. This provides | |
873 | protection against certain security exploits (e.g. writing to text) | |
874 | ||
ea8c64ac CH |
875 | # select if the architecture provides an asm/dma-direct.h header |
876 | config ARCH_HAS_PHYS_TO_DMA | |
877 | bool | |
878 | ||
7a46ec0e KC |
879 | config ARCH_HAS_REFCOUNT |
880 | bool | |
881 | help | |
882 | An architecture selects this when it has implemented refcount_t | |
883 | using open coded assembly primitives that provide an optimized | |
884 | refcount_t implementation, possibly at the expense of some full | |
885 | refcount state checks of CONFIG_REFCOUNT_FULL=y. | |
886 | ||
887 | The refcount overflow check behavior, however, must be retained. | |
888 | Catching overflows is the primary security concern for protecting | |
889 | against bugs in reference counts. | |
890 | ||
fd25d19f KC |
891 | config REFCOUNT_FULL |
892 | bool "Perform full reference count validation at the expense of speed" | |
893 | help | |
894 | Enabling this switches the refcounting infrastructure from a fast | |
895 | unchecked atomic_t implementation to a fully state checked | |
896 | implementation, which can be (slightly) slower but provides protections | |
897 | against various use-after-free conditions that can be used in | |
898 | security flaw exploits. | |
899 | ||
04f264d3 PB |
900 | config HAVE_ARCH_COMPILER_H |
901 | bool | |
902 | help | |
903 | An architecture can select this if it provides an | |
904 | asm/compiler.h header that should be included after | |
905 | linux/compiler-*.h in order to override macro definitions that those | |
906 | headers generally provide. | |
907 | ||
271ca788 AB |
908 | config HAVE_ARCH_PREL32_RELOCATIONS |
909 | bool | |
910 | help | |
911 | May be selected by an architecture if it supports place-relative | |
912 | 32-bit relocations, both in the toolchain and in the module loader, | |
913 | in which case relative references can be used in special sections | |
914 | for PCI fixup, initcalls etc which are only half the size on 64 bit | |
915 | architectures, and don't require runtime relocation on relocatable | |
916 | kernels. | |
917 | ||
ce9084ba AB |
918 | config ARCH_USE_MEMREMAP_PROT |
919 | bool | |
920 | ||
fb346fd9 WL |
921 | config LOCK_EVENT_COUNTS |
922 | bool "Locking event counts collection" | |
923 | depends on DEBUG_FS | |
fb346fd9 WL |
924 | ---help--- |
925 | Enable light-weight counting of various locking related events | |
926 | in the system with minimal performance impact. This reduces | |
927 | the chance of application behavior change because of timing | |
928 | differences. The counts are reported via debugfs. | |
929 | ||
2521f2c2 | 930 | source "kernel/gcov/Kconfig" |
45332b1b MY |
931 | |
932 | source "scripts/gcc-plugins/Kconfig" | |
fa1b5d09 | 933 | |
22471e13 | 934 | endmenu |