Commit | Line | Data |
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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 | ||
c30700db CH |
263 | # |
264 | # Select if arch has an uncached kernel segment and provides the | |
265 | # uncached_kernel_address / cached_kernel_address symbols to use it | |
266 | # | |
267 | config ARCH_HAS_UNCACHED_SEGMENT | |
268 | select ARCH_HAS_DMA_PREP_COHERENT | |
269 | bool | |
270 | ||
0500871f DH |
271 | # Select if arch init_task must go in the __init_task_data section |
272 | config ARCH_TASK_STRUCT_ON_STACK | |
a4a2eb49 TG |
273 | bool |
274 | ||
f5e10287 TG |
275 | # Select if arch has its private alloc_task_struct() function |
276 | config ARCH_TASK_STRUCT_ALLOCATOR | |
277 | bool | |
278 | ||
5905429a KC |
279 | config HAVE_ARCH_THREAD_STRUCT_WHITELIST |
280 | bool | |
281 | depends on !ARCH_TASK_STRUCT_ALLOCATOR | |
282 | help | |
283 | An architecture should select this to provide hardened usercopy | |
284 | knowledge about what region of the thread_struct should be | |
285 | whitelisted for copying to userspace. Normally this is only the | |
286 | FPU registers. Specifically, arch_thread_struct_whitelist() | |
287 | should be implemented. Without this, the entire thread_struct | |
288 | field in task_struct will be left whitelisted. | |
289 | ||
b235beea LT |
290 | # Select if arch has its private alloc_thread_stack() function |
291 | config ARCH_THREAD_STACK_ALLOCATOR | |
f5e10287 TG |
292 | bool |
293 | ||
5aaeb5c0 IM |
294 | # Select if arch wants to size task_struct dynamically via arch_task_struct_size: |
295 | config ARCH_WANTS_DYNAMIC_TASK_STRUCT | |
296 | bool | |
297 | ||
942fa985 YN |
298 | config ARCH_32BIT_OFF_T |
299 | bool | |
300 | depends on !64BIT | |
301 | help | |
302 | All new 32-bit architectures should have 64-bit off_t type on | |
303 | userspace side which corresponds to the loff_t kernel type. This | |
304 | is the requirement for modern ABIs. Some existing architectures | |
305 | still support 32-bit off_t. This option is enabled for all such | |
306 | architectures explicitly. | |
307 | ||
f850c30c HC |
308 | config HAVE_REGS_AND_STACK_ACCESS_API |
309 | bool | |
e01292b1 HC |
310 | help |
311 | This symbol should be selected by an architecure if it supports | |
312 | the API needed to access registers and stack entries from pt_regs, | |
313 | declared in asm/ptrace.h | |
314 | For example the kprobes-based event tracer needs this API. | |
f850c30c | 315 | |
d7822b1e MD |
316 | config HAVE_RSEQ |
317 | bool | |
318 | depends on HAVE_REGS_AND_STACK_ACCESS_API | |
319 | help | |
320 | This symbol should be selected by an architecture if it | |
321 | supports an implementation of restartable sequences. | |
322 | ||
3c88ee19 MH |
323 | config HAVE_FUNCTION_ARG_ACCESS_API |
324 | bool | |
325 | help | |
326 | This symbol should be selected by an architecure if it supports | |
327 | the API needed to access function arguments from pt_regs, | |
328 | declared in asm/ptrace.h | |
329 | ||
9483a578 | 330 | config HAVE_CLK |
9ba16087 | 331 | bool |
9483a578 DB |
332 | help |
333 | The <linux/clk.h> calls support software clock gating and | |
334 | thus are a key power management tool on many systems. | |
335 | ||
62a038d3 P |
336 | config HAVE_HW_BREAKPOINT |
337 | bool | |
99e8c5a3 | 338 | depends on PERF_EVENTS |
62a038d3 | 339 | |
0102752e FW |
340 | config HAVE_MIXED_BREAKPOINTS_REGS |
341 | bool | |
342 | depends on HAVE_HW_BREAKPOINT | |
343 | help | |
344 | Depending on the arch implementation of hardware breakpoints, | |
345 | some of them have separate registers for data and instruction | |
346 | breakpoints addresses, others have mixed registers to store | |
347 | them but define the access type in a control register. | |
348 | Select this option if your arch implements breakpoints under the | |
349 | latter fashion. | |
350 | ||
7c68af6e AK |
351 | config HAVE_USER_RETURN_NOTIFIER |
352 | bool | |
a1922ed6 | 353 | |
c01d4323 FW |
354 | config HAVE_PERF_EVENTS_NMI |
355 | bool | |
23637d47 FW |
356 | help |
357 | System hardware can generate an NMI using the perf event | |
358 | subsystem. Also has support for calculating CPU cycle events | |
359 | to determine how many clock cycles in a given period. | |
c01d4323 | 360 | |
05a4a952 NP |
361 | config HAVE_HARDLOCKUP_DETECTOR_PERF |
362 | bool | |
363 | depends on HAVE_PERF_EVENTS_NMI | |
364 | help | |
365 | The arch chooses to use the generic perf-NMI-based hardlockup | |
366 | detector. Must define HAVE_PERF_EVENTS_NMI. | |
367 | ||
368 | config HAVE_NMI_WATCHDOG | |
369 | depends on HAVE_NMI | |
370 | bool | |
371 | help | |
372 | The arch provides a low level NMI watchdog. It provides | |
373 | asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). | |
374 | ||
375 | config HAVE_HARDLOCKUP_DETECTOR_ARCH | |
376 | bool | |
377 | select HAVE_NMI_WATCHDOG | |
378 | help | |
379 | The arch chooses to provide its own hardlockup detector, which is | |
380 | a superset of the HAVE_NMI_WATCHDOG. It also conforms to config | |
381 | interfaces and parameters provided by hardlockup detector subsystem. | |
382 | ||
c5e63197 JO |
383 | config HAVE_PERF_REGS |
384 | bool | |
385 | help | |
386 | Support selective register dumps for perf events. This includes | |
387 | bit-mapping of each registers and a unique architecture id. | |
388 | ||
c5ebcedb JO |
389 | config HAVE_PERF_USER_STACK_DUMP |
390 | bool | |
391 | help | |
392 | Support user stack dumps for perf event samples. This needs | |
393 | access to the user stack pointer which is not unified across | |
394 | architectures. | |
395 | ||
bf5438fc JB |
396 | config HAVE_ARCH_JUMP_LABEL |
397 | bool | |
398 | ||
50ff18ab AB |
399 | config HAVE_ARCH_JUMP_LABEL_RELATIVE |
400 | bool | |
401 | ||
26723911 PZ |
402 | config HAVE_RCU_TABLE_FREE |
403 | bool | |
404 | ||
96bc9567 | 405 | config HAVE_RCU_TABLE_NO_INVALIDATE |
d86564a2 PZ |
406 | bool |
407 | ||
ed6a7935 PZ |
408 | config HAVE_MMU_GATHER_PAGE_SIZE |
409 | bool | |
410 | ||
952a31c9 MS |
411 | config HAVE_MMU_GATHER_NO_GATHER |
412 | bool | |
413 | ||
df013ffb HY |
414 | config ARCH_HAVE_NMI_SAFE_CMPXCHG |
415 | bool | |
416 | ||
43570fd2 HC |
417 | config HAVE_ALIGNED_STRUCT_PAGE |
418 | bool | |
419 | help | |
420 | This makes sure that struct pages are double word aligned and that | |
421 | e.g. the SLUB allocator can perform double word atomic operations | |
422 | on a struct page for better performance. However selecting this | |
423 | might increase the size of a struct page by a word. | |
424 | ||
4156153c HC |
425 | config HAVE_CMPXCHG_LOCAL |
426 | bool | |
427 | ||
2565409f HC |
428 | config HAVE_CMPXCHG_DOUBLE |
429 | bool | |
430 | ||
77e58496 PM |
431 | config ARCH_WEAK_RELEASE_ACQUIRE |
432 | bool | |
433 | ||
c1d7e01d WD |
434 | config ARCH_WANT_IPC_PARSE_VERSION |
435 | bool | |
436 | ||
437 | config ARCH_WANT_COMPAT_IPC_PARSE_VERSION | |
438 | bool | |
439 | ||
48b25c43 | 440 | config ARCH_WANT_OLD_COMPAT_IPC |
c1d7e01d | 441 | select ARCH_WANT_COMPAT_IPC_PARSE_VERSION |
48b25c43 CM |
442 | bool |
443 | ||
e2cfabdf WD |
444 | config HAVE_ARCH_SECCOMP_FILTER |
445 | bool | |
446 | help | |
fb0fadf9 | 447 | An arch should select this symbol if it provides all of these things: |
bb6ea430 WD |
448 | - syscall_get_arch() |
449 | - syscall_get_arguments() | |
450 | - syscall_rollback() | |
451 | - syscall_set_return_value() | |
fb0fadf9 WD |
452 | - SIGSYS siginfo_t support |
453 | - secure_computing is called from a ptrace_event()-safe context | |
454 | - secure_computing return value is checked and a return value of -1 | |
455 | results in the system call being skipped immediately. | |
48dc92b9 | 456 | - seccomp syscall wired up |
e2cfabdf WD |
457 | |
458 | config SECCOMP_FILTER | |
459 | def_bool y | |
460 | depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET | |
461 | help | |
462 | Enable tasks to build secure computing environments defined | |
463 | in terms of Berkeley Packet Filter programs which implement | |
464 | task-defined system call filtering polices. | |
465 | ||
5fb94e9c | 466 | See Documentation/userspace-api/seccomp_filter.rst for details. |
e2cfabdf | 467 | |
afaef01c AP |
468 | config HAVE_ARCH_STACKLEAK |
469 | bool | |
470 | help | |
471 | An architecture should select this if it has the code which | |
472 | fills the used part of the kernel stack with the STACKLEAK_POISON | |
473 | value before returning from system calls. | |
474 | ||
d148eac0 | 475 | config HAVE_STACKPROTECTOR |
19952a92 KC |
476 | bool |
477 | help | |
478 | An arch should select this symbol if: | |
19952a92 KC |
479 | - it has implemented a stack canary (e.g. __stack_chk_guard) |
480 | ||
2a61f474 MY |
481 | config CC_HAS_STACKPROTECTOR_NONE |
482 | def_bool $(cc-option,-fno-stack-protector) | |
483 | ||
050e9baa | 484 | config STACKPROTECTOR |
2a61f474 | 485 | bool "Stack Protector buffer overflow detection" |
d148eac0 | 486 | depends on HAVE_STACKPROTECTOR |
2a61f474 MY |
487 | depends on $(cc-option,-fstack-protector) |
488 | default y | |
19952a92 | 489 | help |
8779657d | 490 | This option turns on the "stack-protector" GCC feature. This |
19952a92 KC |
491 | feature puts, at the beginning of functions, a canary value on |
492 | the stack just before the return address, and validates | |
493 | the value just before actually returning. Stack based buffer | |
494 | overflows (that need to overwrite this return address) now also | |
495 | overwrite the canary, which gets detected and the attack is then | |
496 | neutralized via a kernel panic. | |
497 | ||
8779657d KC |
498 | Functions will have the stack-protector canary logic added if they |
499 | have an 8-byte or larger character array on the stack. | |
500 | ||
19952a92 | 501 | This feature requires gcc version 4.2 or above, or a distribution |
8779657d KC |
502 | gcc with the feature backported ("-fstack-protector"). |
503 | ||
504 | On an x86 "defconfig" build, this feature adds canary checks to | |
505 | about 3% of all kernel functions, which increases kernel code size | |
506 | by about 0.3%. | |
507 | ||
050e9baa | 508 | config STACKPROTECTOR_STRONG |
2a61f474 | 509 | bool "Strong Stack Protector" |
050e9baa | 510 | depends on STACKPROTECTOR |
2a61f474 MY |
511 | depends on $(cc-option,-fstack-protector-strong) |
512 | default y | |
8779657d KC |
513 | help |
514 | Functions will have the stack-protector canary logic added in any | |
515 | of the following conditions: | |
516 | ||
517 | - local variable's address used as part of the right hand side of an | |
518 | assignment or function argument | |
519 | - local variable is an array (or union containing an array), | |
520 | regardless of array type or length | |
521 | - uses register local variables | |
522 | ||
523 | This feature requires gcc version 4.9 or above, or a distribution | |
524 | gcc with the feature backported ("-fstack-protector-strong"). | |
525 | ||
526 | On an x86 "defconfig" build, this feature adds canary checks to | |
527 | about 20% of all kernel functions, which increases the kernel code | |
528 | size by about 2%. | |
529 | ||
0f60a8ef KC |
530 | config HAVE_ARCH_WITHIN_STACK_FRAMES |
531 | bool | |
532 | help | |
533 | An architecture should select this if it can walk the kernel stack | |
534 | frames to determine if an object is part of either the arguments | |
535 | or local variables (i.e. that it excludes saved return addresses, | |
536 | and similar) by implementing an inline arch_within_stack_frames(), | |
537 | which is used by CONFIG_HARDENED_USERCOPY. | |
538 | ||
91d1aa43 | 539 | config HAVE_CONTEXT_TRACKING |
2b1d5024 FW |
540 | bool |
541 | help | |
91d1aa43 FW |
542 | Provide kernel/user boundaries probes necessary for subsystems |
543 | that need it, such as userspace RCU extended quiescent state. | |
544 | Syscalls need to be wrapped inside user_exit()-user_enter() through | |
545 | the slow path using TIF_NOHZ flag. Exceptions handlers must be | |
546 | wrapped as well. Irqs are already protected inside | |
547 | rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on | |
548 | irq exit still need to be protected. | |
2b1d5024 | 549 | |
b952741c FW |
550 | config HAVE_VIRT_CPU_ACCOUNTING |
551 | bool | |
552 | ||
40565b5a SG |
553 | config ARCH_HAS_SCALED_CPUTIME |
554 | bool | |
555 | ||
554b0004 KH |
556 | config HAVE_VIRT_CPU_ACCOUNTING_GEN |
557 | bool | |
558 | default y if 64BIT | |
559 | help | |
560 | With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. | |
561 | Before enabling this option, arch code must be audited | |
562 | to ensure there are no races in concurrent read/write of | |
563 | cputime_t. For example, reading/writing 64-bit cputime_t on | |
564 | some 32-bit arches may require multiple accesses, so proper | |
565 | locking is needed to protect against concurrent accesses. | |
566 | ||
567 | ||
fdf9c356 FW |
568 | config HAVE_IRQ_TIME_ACCOUNTING |
569 | bool | |
570 | help | |
571 | Archs need to ensure they use a high enough resolution clock to | |
572 | support irq time accounting and then call enable_sched_clock_irqtime(). | |
573 | ||
2c91bd4a JFG |
574 | config HAVE_MOVE_PMD |
575 | bool | |
576 | help | |
577 | Archs that select this are able to move page tables at the PMD level. | |
578 | ||
15626062 GS |
579 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE |
580 | bool | |
581 | ||
a00cc7d9 MW |
582 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
583 | bool | |
584 | ||
0ddab1d2 TK |
585 | config HAVE_ARCH_HUGE_VMAP |
586 | bool | |
587 | ||
0f8975ec PE |
588 | config HAVE_ARCH_SOFT_DIRTY |
589 | bool | |
590 | ||
786d35d4 DH |
591 | config HAVE_MOD_ARCH_SPECIFIC |
592 | bool | |
593 | help | |
594 | The arch uses struct mod_arch_specific to store data. Many arches | |
595 | just need a simple module loader without arch specific data - those | |
596 | should not enable this. | |
597 | ||
598 | config MODULES_USE_ELF_RELA | |
599 | bool | |
600 | help | |
601 | Modules only use ELF RELA relocations. Modules with ELF REL | |
602 | relocations will give an error. | |
603 | ||
604 | config MODULES_USE_ELF_REL | |
605 | bool | |
606 | help | |
607 | Modules only use ELF REL relocations. Modules with ELF RELA | |
608 | relocations will give an error. | |
609 | ||
cc1f0274 FW |
610 | config HAVE_IRQ_EXIT_ON_IRQ_STACK |
611 | bool | |
612 | help | |
613 | Architecture doesn't only execute the irq handler on the irq stack | |
614 | but also irq_exit(). This way we can process softirqs on this irq | |
615 | stack instead of switching to a new one when we call __do_softirq() | |
616 | in the end of an hardirq. | |
617 | This spares a stack switch and improves cache usage on softirq | |
618 | processing. | |
619 | ||
235a8f02 KS |
620 | config PGTABLE_LEVELS |
621 | int | |
622 | default 2 | |
623 | ||
2b68f6ca KC |
624 | config ARCH_HAS_ELF_RANDOMIZE |
625 | bool | |
626 | help | |
627 | An architecture supports choosing randomized locations for | |
628 | stack, mmap, brk, and ET_DYN. Defined functions: | |
629 | - arch_mmap_rnd() | |
204db6ed | 630 | - arch_randomize_brk() |
2b68f6ca | 631 | |
d07e2259 DC |
632 | config HAVE_ARCH_MMAP_RND_BITS |
633 | bool | |
634 | help | |
635 | An arch should select this symbol if it supports setting a variable | |
636 | number of bits for use in establishing the base address for mmap | |
637 | allocations, has MMU enabled and provides values for both: | |
638 | - ARCH_MMAP_RND_BITS_MIN | |
639 | - ARCH_MMAP_RND_BITS_MAX | |
640 | ||
5f56a5df JS |
641 | config HAVE_EXIT_THREAD |
642 | bool | |
643 | help | |
644 | An architecture implements exit_thread. | |
645 | ||
d07e2259 DC |
646 | config ARCH_MMAP_RND_BITS_MIN |
647 | int | |
648 | ||
649 | config ARCH_MMAP_RND_BITS_MAX | |
650 | int | |
651 | ||
652 | config ARCH_MMAP_RND_BITS_DEFAULT | |
653 | int | |
654 | ||
655 | config ARCH_MMAP_RND_BITS | |
656 | int "Number of bits to use for ASLR of mmap base address" if EXPERT | |
657 | range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX | |
658 | default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT | |
659 | default ARCH_MMAP_RND_BITS_MIN | |
660 | depends on HAVE_ARCH_MMAP_RND_BITS | |
661 | help | |
662 | This value can be used to select the number of bits to use to | |
663 | determine the random offset to the base address of vma regions | |
664 | resulting from mmap allocations. This value will be bounded | |
665 | by the architecture's minimum and maximum supported values. | |
666 | ||
667 | This value can be changed after boot using the | |
668 | /proc/sys/vm/mmap_rnd_bits tunable | |
669 | ||
670 | config HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
671 | bool | |
672 | help | |
673 | An arch should select this symbol if it supports running applications | |
674 | in compatibility mode, supports setting a variable number of bits for | |
675 | use in establishing the base address for mmap allocations, has MMU | |
676 | enabled and provides values for both: | |
677 | - ARCH_MMAP_RND_COMPAT_BITS_MIN | |
678 | - ARCH_MMAP_RND_COMPAT_BITS_MAX | |
679 | ||
680 | config ARCH_MMAP_RND_COMPAT_BITS_MIN | |
681 | int | |
682 | ||
683 | config ARCH_MMAP_RND_COMPAT_BITS_MAX | |
684 | int | |
685 | ||
686 | config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
687 | int | |
688 | ||
689 | config ARCH_MMAP_RND_COMPAT_BITS | |
690 | int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT | |
691 | range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX | |
692 | default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
693 | default ARCH_MMAP_RND_COMPAT_BITS_MIN | |
694 | depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
695 | help | |
696 | This value can be used to select the number of bits to use to | |
697 | determine the random offset to the base address of vma regions | |
698 | resulting from mmap allocations for compatible applications This | |
699 | value will be bounded by the architecture's minimum and maximum | |
700 | supported values. | |
701 | ||
702 | This value can be changed after boot using the | |
703 | /proc/sys/vm/mmap_rnd_compat_bits tunable | |
704 | ||
1b028f78 DS |
705 | config HAVE_ARCH_COMPAT_MMAP_BASES |
706 | bool | |
707 | help | |
708 | This allows 64bit applications to invoke 32-bit mmap() syscall | |
709 | and vice-versa 32-bit applications to call 64-bit mmap(). | |
710 | Required for applications doing different bitness syscalls. | |
711 | ||
3033f14a JT |
712 | config HAVE_COPY_THREAD_TLS |
713 | bool | |
714 | help | |
715 | Architecture provides copy_thread_tls to accept tls argument via | |
716 | normal C parameter passing, rather than extracting the syscall | |
717 | argument from pt_regs. | |
718 | ||
b9ab5ebb JP |
719 | config HAVE_STACK_VALIDATION |
720 | bool | |
721 | help | |
722 | Architecture supports the 'objtool check' host tool command, which | |
723 | performs compile-time stack metadata validation. | |
724 | ||
af085d90 JP |
725 | config HAVE_RELIABLE_STACKTRACE |
726 | bool | |
727 | help | |
728 | Architecture has a save_stack_trace_tsk_reliable() function which | |
729 | only returns a stack trace if it can guarantee the trace is reliable. | |
730 | ||
468a9428 GS |
731 | config HAVE_ARCH_HASH |
732 | bool | |
733 | default n | |
734 | help | |
735 | If this is set, the architecture provides an <asm/hash.h> | |
736 | file which provides platform-specific implementations of some | |
737 | functions in <linux/hash.h> or fs/namei.c. | |
738 | ||
666047fe FT |
739 | config HAVE_ARCH_NVRAM_OPS |
740 | bool | |
741 | ||
3a495511 WBG |
742 | config ISA_BUS_API |
743 | def_bool ISA | |
744 | ||
d2125043 AV |
745 | # |
746 | # ABI hall of shame | |
747 | # | |
748 | config CLONE_BACKWARDS | |
749 | bool | |
750 | help | |
751 | Architecture has tls passed as the 4th argument of clone(2), | |
752 | not the 5th one. | |
753 | ||
754 | config CLONE_BACKWARDS2 | |
755 | bool | |
756 | help | |
757 | Architecture has the first two arguments of clone(2) swapped. | |
758 | ||
dfa9771a MS |
759 | config CLONE_BACKWARDS3 |
760 | bool | |
761 | help | |
762 | Architecture has tls passed as the 3rd argument of clone(2), | |
763 | not the 5th one. | |
764 | ||
eaca6eae AV |
765 | config ODD_RT_SIGACTION |
766 | bool | |
767 | help | |
768 | Architecture has unusual rt_sigaction(2) arguments | |
769 | ||
0a0e8cdf AV |
770 | config OLD_SIGSUSPEND |
771 | bool | |
772 | help | |
773 | Architecture has old sigsuspend(2) syscall, of one-argument variety | |
774 | ||
775 | config OLD_SIGSUSPEND3 | |
776 | bool | |
777 | help | |
778 | Even weirder antique ABI - three-argument sigsuspend(2) | |
779 | ||
495dfbf7 AV |
780 | config OLD_SIGACTION |
781 | bool | |
782 | help | |
783 | Architecture has old sigaction(2) syscall. Nope, not the same | |
784 | as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), | |
785 | but fairly different variant of sigaction(2), thanks to OSF/1 | |
786 | compatibility... | |
787 | ||
788 | config COMPAT_OLD_SIGACTION | |
789 | bool | |
790 | ||
d4703dda | 791 | config 64BIT_TIME |
f3d96467 | 792 | def_bool y |
d4703dda DD |
793 | help |
794 | This should be selected by all architectures that need to support | |
795 | new system calls with a 64-bit time_t. This is relevant on all 32-bit | |
796 | architectures, and 64-bit architectures as part of compat syscall | |
797 | handling. | |
798 | ||
17435e5f | 799 | config COMPAT_32BIT_TIME |
00bf25d6 | 800 | def_bool !64BIT || COMPAT |
17435e5f DD |
801 | help |
802 | This enables 32 bit time_t support in addition to 64 bit time_t support. | |
803 | This is relevant on all 32-bit architectures, and 64-bit architectures | |
804 | as part of compat syscall handling. | |
805 | ||
0d4a619b CH |
806 | config ARCH_NO_COHERENT_DMA_MMAP |
807 | bool | |
808 | ||
87a4c375 CH |
809 | config ARCH_NO_PREEMPT |
810 | bool | |
811 | ||
fff7fb0b ZZ |
812 | config CPU_NO_EFFICIENT_FFS |
813 | def_bool n | |
814 | ||
ba14a194 AL |
815 | config HAVE_ARCH_VMAP_STACK |
816 | def_bool n | |
817 | help | |
818 | An arch should select this symbol if it can support kernel stacks | |
819 | in vmalloc space. This means: | |
820 | ||
821 | - vmalloc space must be large enough to hold many kernel stacks. | |
822 | This may rule out many 32-bit architectures. | |
823 | ||
824 | - Stacks in vmalloc space need to work reliably. For example, if | |
825 | vmap page tables are created on demand, either this mechanism | |
826 | needs to work while the stack points to a virtual address with | |
827 | unpopulated page tables or arch code (switch_to() and switch_mm(), | |
828 | most likely) needs to ensure that the stack's page table entries | |
829 | are populated before running on a possibly unpopulated stack. | |
830 | ||
831 | - If the stack overflows into a guard page, something reasonable | |
832 | should happen. The definition of "reasonable" is flexible, but | |
833 | instantly rebooting without logging anything would be unfriendly. | |
834 | ||
835 | config VMAP_STACK | |
836 | default y | |
837 | bool "Use a virtually-mapped stack" | |
838 | depends on HAVE_ARCH_VMAP_STACK && !KASAN | |
839 | ---help--- | |
840 | Enable this if you want the use virtually-mapped kernel stacks | |
841 | with guard pages. This causes kernel stack overflows to be | |
842 | caught immediately rather than causing difficult-to-diagnose | |
843 | corruption. | |
844 | ||
845 | This is presently incompatible with KASAN because KASAN expects | |
846 | the stack to map directly to the KASAN shadow map using a formula | |
847 | that is incorrect if the stack is in vmalloc space. | |
848 | ||
ad21fc4f LA |
849 | config ARCH_OPTIONAL_KERNEL_RWX |
850 | def_bool n | |
851 | ||
852 | config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
853 | def_bool n | |
854 | ||
855 | config ARCH_HAS_STRICT_KERNEL_RWX | |
856 | def_bool n | |
857 | ||
0f5bf6d0 | 858 | config STRICT_KERNEL_RWX |
ad21fc4f LA |
859 | bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX |
860 | depends on ARCH_HAS_STRICT_KERNEL_RWX | |
861 | default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
862 | help | |
863 | If this is set, kernel text and rodata memory will be made read-only, | |
864 | and non-text memory will be made non-executable. This provides | |
865 | protection against certain security exploits (e.g. executing the heap | |
866 | or modifying text) | |
867 | ||
868 | These features are considered standard security practice these days. | |
869 | You should say Y here in almost all cases. | |
870 | ||
871 | config ARCH_HAS_STRICT_MODULE_RWX | |
872 | def_bool n | |
873 | ||
0f5bf6d0 | 874 | config STRICT_MODULE_RWX |
ad21fc4f LA |
875 | bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX |
876 | depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES | |
877 | default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
878 | help | |
879 | If this is set, module text and rodata memory will be made read-only, | |
880 | and non-text memory will be made non-executable. This provides | |
881 | protection against certain security exploits (e.g. writing to text) | |
882 | ||
ea8c64ac CH |
883 | # select if the architecture provides an asm/dma-direct.h header |
884 | config ARCH_HAS_PHYS_TO_DMA | |
885 | bool | |
886 | ||
7a46ec0e KC |
887 | config ARCH_HAS_REFCOUNT |
888 | bool | |
889 | help | |
890 | An architecture selects this when it has implemented refcount_t | |
891 | using open coded assembly primitives that provide an optimized | |
892 | refcount_t implementation, possibly at the expense of some full | |
893 | refcount state checks of CONFIG_REFCOUNT_FULL=y. | |
894 | ||
895 | The refcount overflow check behavior, however, must be retained. | |
896 | Catching overflows is the primary security concern for protecting | |
897 | against bugs in reference counts. | |
898 | ||
fd25d19f KC |
899 | config REFCOUNT_FULL |
900 | bool "Perform full reference count validation at the expense of speed" | |
901 | help | |
902 | Enabling this switches the refcounting infrastructure from a fast | |
903 | unchecked atomic_t implementation to a fully state checked | |
904 | implementation, which can be (slightly) slower but provides protections | |
905 | against various use-after-free conditions that can be used in | |
906 | security flaw exploits. | |
907 | ||
04f264d3 PB |
908 | config HAVE_ARCH_COMPILER_H |
909 | bool | |
910 | help | |
911 | An architecture can select this if it provides an | |
912 | asm/compiler.h header that should be included after | |
913 | linux/compiler-*.h in order to override macro definitions that those | |
914 | headers generally provide. | |
915 | ||
271ca788 AB |
916 | config HAVE_ARCH_PREL32_RELOCATIONS |
917 | bool | |
918 | help | |
919 | May be selected by an architecture if it supports place-relative | |
920 | 32-bit relocations, both in the toolchain and in the module loader, | |
921 | in which case relative references can be used in special sections | |
922 | for PCI fixup, initcalls etc which are only half the size on 64 bit | |
923 | architectures, and don't require runtime relocation on relocatable | |
924 | kernels. | |
925 | ||
ce9084ba AB |
926 | config ARCH_USE_MEMREMAP_PROT |
927 | bool | |
928 | ||
fb346fd9 WL |
929 | config LOCK_EVENT_COUNTS |
930 | bool "Locking event counts collection" | |
931 | depends on DEBUG_FS | |
fb346fd9 WL |
932 | ---help--- |
933 | Enable light-weight counting of various locking related events | |
934 | in the system with minimal performance impact. This reduces | |
935 | the chance of application behavior change because of timing | |
936 | differences. The counts are reported via debugfs. | |
937 | ||
2521f2c2 | 938 | source "kernel/gcov/Kconfig" |
45332b1b MY |
939 | |
940 | source "scripts/gcc-plugins/Kconfig" | |
fa1b5d09 | 941 | |
22471e13 | 942 | endmenu |