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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 | ||
d2852a22 DB |
248 | # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h |
249 | config ARCH_HAS_SET_MEMORY | |
250 | bool | |
251 | ||
0500871f DH |
252 | # Select if arch init_task must go in the __init_task_data section |
253 | config ARCH_TASK_STRUCT_ON_STACK | |
a4a2eb49 TG |
254 | bool |
255 | ||
f5e10287 TG |
256 | # Select if arch has its private alloc_task_struct() function |
257 | config ARCH_TASK_STRUCT_ALLOCATOR | |
258 | bool | |
259 | ||
5905429a KC |
260 | config HAVE_ARCH_THREAD_STRUCT_WHITELIST |
261 | bool | |
262 | depends on !ARCH_TASK_STRUCT_ALLOCATOR | |
263 | help | |
264 | An architecture should select this to provide hardened usercopy | |
265 | knowledge about what region of the thread_struct should be | |
266 | whitelisted for copying to userspace. Normally this is only the | |
267 | FPU registers. Specifically, arch_thread_struct_whitelist() | |
268 | should be implemented. Without this, the entire thread_struct | |
269 | field in task_struct will be left whitelisted. | |
270 | ||
b235beea LT |
271 | # Select if arch has its private alloc_thread_stack() function |
272 | config ARCH_THREAD_STACK_ALLOCATOR | |
f5e10287 TG |
273 | bool |
274 | ||
5aaeb5c0 IM |
275 | # Select if arch wants to size task_struct dynamically via arch_task_struct_size: |
276 | config ARCH_WANTS_DYNAMIC_TASK_STRUCT | |
277 | bool | |
278 | ||
f850c30c HC |
279 | config HAVE_REGS_AND_STACK_ACCESS_API |
280 | bool | |
e01292b1 HC |
281 | help |
282 | This symbol should be selected by an architecure if it supports | |
283 | the API needed to access registers and stack entries from pt_regs, | |
284 | declared in asm/ptrace.h | |
285 | For example the kprobes-based event tracer needs this API. | |
f850c30c | 286 | |
d7822b1e MD |
287 | config HAVE_RSEQ |
288 | bool | |
289 | depends on HAVE_REGS_AND_STACK_ACCESS_API | |
290 | help | |
291 | This symbol should be selected by an architecture if it | |
292 | supports an implementation of restartable sequences. | |
293 | ||
3c88ee19 MH |
294 | config HAVE_FUNCTION_ARG_ACCESS_API |
295 | bool | |
296 | help | |
297 | This symbol should be selected by an architecure if it supports | |
298 | the API needed to access function arguments from pt_regs, | |
299 | declared in asm/ptrace.h | |
300 | ||
9483a578 | 301 | config HAVE_CLK |
9ba16087 | 302 | bool |
9483a578 DB |
303 | help |
304 | The <linux/clk.h> calls support software clock gating and | |
305 | thus are a key power management tool on many systems. | |
306 | ||
62a038d3 P |
307 | config HAVE_HW_BREAKPOINT |
308 | bool | |
99e8c5a3 | 309 | depends on PERF_EVENTS |
62a038d3 | 310 | |
0102752e FW |
311 | config HAVE_MIXED_BREAKPOINTS_REGS |
312 | bool | |
313 | depends on HAVE_HW_BREAKPOINT | |
314 | help | |
315 | Depending on the arch implementation of hardware breakpoints, | |
316 | some of them have separate registers for data and instruction | |
317 | breakpoints addresses, others have mixed registers to store | |
318 | them but define the access type in a control register. | |
319 | Select this option if your arch implements breakpoints under the | |
320 | latter fashion. | |
321 | ||
7c68af6e AK |
322 | config HAVE_USER_RETURN_NOTIFIER |
323 | bool | |
a1922ed6 | 324 | |
c01d4323 FW |
325 | config HAVE_PERF_EVENTS_NMI |
326 | bool | |
23637d47 FW |
327 | help |
328 | System hardware can generate an NMI using the perf event | |
329 | subsystem. Also has support for calculating CPU cycle events | |
330 | to determine how many clock cycles in a given period. | |
c01d4323 | 331 | |
05a4a952 NP |
332 | config HAVE_HARDLOCKUP_DETECTOR_PERF |
333 | bool | |
334 | depends on HAVE_PERF_EVENTS_NMI | |
335 | help | |
336 | The arch chooses to use the generic perf-NMI-based hardlockup | |
337 | detector. Must define HAVE_PERF_EVENTS_NMI. | |
338 | ||
339 | config HAVE_NMI_WATCHDOG | |
340 | depends on HAVE_NMI | |
341 | bool | |
342 | help | |
343 | The arch provides a low level NMI watchdog. It provides | |
344 | asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). | |
345 | ||
346 | config HAVE_HARDLOCKUP_DETECTOR_ARCH | |
347 | bool | |
348 | select HAVE_NMI_WATCHDOG | |
349 | help | |
350 | The arch chooses to provide its own hardlockup detector, which is | |
351 | a superset of the HAVE_NMI_WATCHDOG. It also conforms to config | |
352 | interfaces and parameters provided by hardlockup detector subsystem. | |
353 | ||
c5e63197 JO |
354 | config HAVE_PERF_REGS |
355 | bool | |
356 | help | |
357 | Support selective register dumps for perf events. This includes | |
358 | bit-mapping of each registers and a unique architecture id. | |
359 | ||
c5ebcedb JO |
360 | config HAVE_PERF_USER_STACK_DUMP |
361 | bool | |
362 | help | |
363 | Support user stack dumps for perf event samples. This needs | |
364 | access to the user stack pointer which is not unified across | |
365 | architectures. | |
366 | ||
bf5438fc JB |
367 | config HAVE_ARCH_JUMP_LABEL |
368 | bool | |
369 | ||
50ff18ab AB |
370 | config HAVE_ARCH_JUMP_LABEL_RELATIVE |
371 | bool | |
372 | ||
26723911 PZ |
373 | config HAVE_RCU_TABLE_FREE |
374 | bool | |
375 | ||
d86564a2 PZ |
376 | config HAVE_RCU_TABLE_INVALIDATE |
377 | bool | |
378 | ||
df013ffb HY |
379 | config ARCH_HAVE_NMI_SAFE_CMPXCHG |
380 | bool | |
381 | ||
43570fd2 HC |
382 | config HAVE_ALIGNED_STRUCT_PAGE |
383 | bool | |
384 | help | |
385 | This makes sure that struct pages are double word aligned and that | |
386 | e.g. the SLUB allocator can perform double word atomic operations | |
387 | on a struct page for better performance. However selecting this | |
388 | might increase the size of a struct page by a word. | |
389 | ||
4156153c HC |
390 | config HAVE_CMPXCHG_LOCAL |
391 | bool | |
392 | ||
2565409f HC |
393 | config HAVE_CMPXCHG_DOUBLE |
394 | bool | |
395 | ||
77e58496 PM |
396 | config ARCH_WEAK_RELEASE_ACQUIRE |
397 | bool | |
398 | ||
c1d7e01d WD |
399 | config ARCH_WANT_IPC_PARSE_VERSION |
400 | bool | |
401 | ||
402 | config ARCH_WANT_COMPAT_IPC_PARSE_VERSION | |
403 | bool | |
404 | ||
48b25c43 | 405 | config ARCH_WANT_OLD_COMPAT_IPC |
c1d7e01d | 406 | select ARCH_WANT_COMPAT_IPC_PARSE_VERSION |
48b25c43 CM |
407 | bool |
408 | ||
e2cfabdf WD |
409 | config HAVE_ARCH_SECCOMP_FILTER |
410 | bool | |
411 | help | |
fb0fadf9 | 412 | An arch should select this symbol if it provides all of these things: |
bb6ea430 WD |
413 | - syscall_get_arch() |
414 | - syscall_get_arguments() | |
415 | - syscall_rollback() | |
416 | - syscall_set_return_value() | |
fb0fadf9 WD |
417 | - SIGSYS siginfo_t support |
418 | - secure_computing is called from a ptrace_event()-safe context | |
419 | - secure_computing return value is checked and a return value of -1 | |
420 | results in the system call being skipped immediately. | |
48dc92b9 | 421 | - seccomp syscall wired up |
e2cfabdf WD |
422 | |
423 | config SECCOMP_FILTER | |
424 | def_bool y | |
425 | depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET | |
426 | help | |
427 | Enable tasks to build secure computing environments defined | |
428 | in terms of Berkeley Packet Filter programs which implement | |
429 | task-defined system call filtering polices. | |
430 | ||
5fb94e9c | 431 | See Documentation/userspace-api/seccomp_filter.rst for details. |
e2cfabdf | 432 | |
afaef01c AP |
433 | config HAVE_ARCH_STACKLEAK |
434 | bool | |
435 | help | |
436 | An architecture should select this if it has the code which | |
437 | fills the used part of the kernel stack with the STACKLEAK_POISON | |
438 | value before returning from system calls. | |
439 | ||
d148eac0 | 440 | config HAVE_STACKPROTECTOR |
19952a92 KC |
441 | bool |
442 | help | |
443 | An arch should select this symbol if: | |
19952a92 KC |
444 | - it has implemented a stack canary (e.g. __stack_chk_guard) |
445 | ||
2a61f474 MY |
446 | config CC_HAS_STACKPROTECTOR_NONE |
447 | def_bool $(cc-option,-fno-stack-protector) | |
448 | ||
050e9baa | 449 | config STACKPROTECTOR |
2a61f474 | 450 | bool "Stack Protector buffer overflow detection" |
d148eac0 | 451 | depends on HAVE_STACKPROTECTOR |
2a61f474 MY |
452 | depends on $(cc-option,-fstack-protector) |
453 | default y | |
19952a92 | 454 | help |
8779657d | 455 | This option turns on the "stack-protector" GCC feature. This |
19952a92 KC |
456 | feature puts, at the beginning of functions, a canary value on |
457 | the stack just before the return address, and validates | |
458 | the value just before actually returning. Stack based buffer | |
459 | overflows (that need to overwrite this return address) now also | |
460 | overwrite the canary, which gets detected and the attack is then | |
461 | neutralized via a kernel panic. | |
462 | ||
8779657d KC |
463 | Functions will have the stack-protector canary logic added if they |
464 | have an 8-byte or larger character array on the stack. | |
465 | ||
19952a92 | 466 | This feature requires gcc version 4.2 or above, or a distribution |
8779657d KC |
467 | gcc with the feature backported ("-fstack-protector"). |
468 | ||
469 | On an x86 "defconfig" build, this feature adds canary checks to | |
470 | about 3% of all kernel functions, which increases kernel code size | |
471 | by about 0.3%. | |
472 | ||
050e9baa | 473 | config STACKPROTECTOR_STRONG |
2a61f474 | 474 | bool "Strong Stack Protector" |
050e9baa | 475 | depends on STACKPROTECTOR |
2a61f474 MY |
476 | depends on $(cc-option,-fstack-protector-strong) |
477 | default y | |
8779657d KC |
478 | help |
479 | Functions will have the stack-protector canary logic added in any | |
480 | of the following conditions: | |
481 | ||
482 | - local variable's address used as part of the right hand side of an | |
483 | assignment or function argument | |
484 | - local variable is an array (or union containing an array), | |
485 | regardless of array type or length | |
486 | - uses register local variables | |
487 | ||
488 | This feature requires gcc version 4.9 or above, or a distribution | |
489 | gcc with the feature backported ("-fstack-protector-strong"). | |
490 | ||
491 | On an x86 "defconfig" build, this feature adds canary checks to | |
492 | about 20% of all kernel functions, which increases the kernel code | |
493 | size by about 2%. | |
494 | ||
0f60a8ef KC |
495 | config HAVE_ARCH_WITHIN_STACK_FRAMES |
496 | bool | |
497 | help | |
498 | An architecture should select this if it can walk the kernel stack | |
499 | frames to determine if an object is part of either the arguments | |
500 | or local variables (i.e. that it excludes saved return addresses, | |
501 | and similar) by implementing an inline arch_within_stack_frames(), | |
502 | which is used by CONFIG_HARDENED_USERCOPY. | |
503 | ||
91d1aa43 | 504 | config HAVE_CONTEXT_TRACKING |
2b1d5024 FW |
505 | bool |
506 | help | |
91d1aa43 FW |
507 | Provide kernel/user boundaries probes necessary for subsystems |
508 | that need it, such as userspace RCU extended quiescent state. | |
509 | Syscalls need to be wrapped inside user_exit()-user_enter() through | |
510 | the slow path using TIF_NOHZ flag. Exceptions handlers must be | |
511 | wrapped as well. Irqs are already protected inside | |
512 | rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on | |
513 | irq exit still need to be protected. | |
2b1d5024 | 514 | |
b952741c FW |
515 | config HAVE_VIRT_CPU_ACCOUNTING |
516 | bool | |
517 | ||
40565b5a SG |
518 | config ARCH_HAS_SCALED_CPUTIME |
519 | bool | |
520 | ||
554b0004 KH |
521 | config HAVE_VIRT_CPU_ACCOUNTING_GEN |
522 | bool | |
523 | default y if 64BIT | |
524 | help | |
525 | With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. | |
526 | Before enabling this option, arch code must be audited | |
527 | to ensure there are no races in concurrent read/write of | |
528 | cputime_t. For example, reading/writing 64-bit cputime_t on | |
529 | some 32-bit arches may require multiple accesses, so proper | |
530 | locking is needed to protect against concurrent accesses. | |
531 | ||
532 | ||
fdf9c356 FW |
533 | config HAVE_IRQ_TIME_ACCOUNTING |
534 | bool | |
535 | help | |
536 | Archs need to ensure they use a high enough resolution clock to | |
537 | support irq time accounting and then call enable_sched_clock_irqtime(). | |
538 | ||
2c91bd4a JFG |
539 | config HAVE_MOVE_PMD |
540 | bool | |
541 | help | |
542 | Archs that select this are able to move page tables at the PMD level. | |
543 | ||
15626062 GS |
544 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE |
545 | bool | |
546 | ||
a00cc7d9 MW |
547 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
548 | bool | |
549 | ||
0ddab1d2 TK |
550 | config HAVE_ARCH_HUGE_VMAP |
551 | bool | |
552 | ||
0f8975ec PE |
553 | config HAVE_ARCH_SOFT_DIRTY |
554 | bool | |
555 | ||
786d35d4 DH |
556 | config HAVE_MOD_ARCH_SPECIFIC |
557 | bool | |
558 | help | |
559 | The arch uses struct mod_arch_specific to store data. Many arches | |
560 | just need a simple module loader without arch specific data - those | |
561 | should not enable this. | |
562 | ||
563 | config MODULES_USE_ELF_RELA | |
564 | bool | |
565 | help | |
566 | Modules only use ELF RELA relocations. Modules with ELF REL | |
567 | relocations will give an error. | |
568 | ||
569 | config MODULES_USE_ELF_REL | |
570 | bool | |
571 | help | |
572 | Modules only use ELF REL relocations. Modules with ELF RELA | |
573 | relocations will give an error. | |
574 | ||
cc1f0274 FW |
575 | config HAVE_IRQ_EXIT_ON_IRQ_STACK |
576 | bool | |
577 | help | |
578 | Architecture doesn't only execute the irq handler on the irq stack | |
579 | but also irq_exit(). This way we can process softirqs on this irq | |
580 | stack instead of switching to a new one when we call __do_softirq() | |
581 | in the end of an hardirq. | |
582 | This spares a stack switch and improves cache usage on softirq | |
583 | processing. | |
584 | ||
235a8f02 KS |
585 | config PGTABLE_LEVELS |
586 | int | |
587 | default 2 | |
588 | ||
2b68f6ca KC |
589 | config ARCH_HAS_ELF_RANDOMIZE |
590 | bool | |
591 | help | |
592 | An architecture supports choosing randomized locations for | |
593 | stack, mmap, brk, and ET_DYN. Defined functions: | |
594 | - arch_mmap_rnd() | |
204db6ed | 595 | - arch_randomize_brk() |
2b68f6ca | 596 | |
d07e2259 DC |
597 | config HAVE_ARCH_MMAP_RND_BITS |
598 | bool | |
599 | help | |
600 | An arch should select this symbol if it supports setting a variable | |
601 | number of bits for use in establishing the base address for mmap | |
602 | allocations, has MMU enabled and provides values for both: | |
603 | - ARCH_MMAP_RND_BITS_MIN | |
604 | - ARCH_MMAP_RND_BITS_MAX | |
605 | ||
5f56a5df JS |
606 | config HAVE_EXIT_THREAD |
607 | bool | |
608 | help | |
609 | An architecture implements exit_thread. | |
610 | ||
d07e2259 DC |
611 | config ARCH_MMAP_RND_BITS_MIN |
612 | int | |
613 | ||
614 | config ARCH_MMAP_RND_BITS_MAX | |
615 | int | |
616 | ||
617 | config ARCH_MMAP_RND_BITS_DEFAULT | |
618 | int | |
619 | ||
620 | config ARCH_MMAP_RND_BITS | |
621 | int "Number of bits to use for ASLR of mmap base address" if EXPERT | |
622 | range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX | |
623 | default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT | |
624 | default ARCH_MMAP_RND_BITS_MIN | |
625 | depends on HAVE_ARCH_MMAP_RND_BITS | |
626 | help | |
627 | This value can be used to select the number of bits to use to | |
628 | determine the random offset to the base address of vma regions | |
629 | resulting from mmap allocations. This value will be bounded | |
630 | by the architecture's minimum and maximum supported values. | |
631 | ||
632 | This value can be changed after boot using the | |
633 | /proc/sys/vm/mmap_rnd_bits tunable | |
634 | ||
635 | config HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
636 | bool | |
637 | help | |
638 | An arch should select this symbol if it supports running applications | |
639 | in compatibility mode, supports setting a variable number of bits for | |
640 | use in establishing the base address for mmap allocations, has MMU | |
641 | enabled and provides values for both: | |
642 | - ARCH_MMAP_RND_COMPAT_BITS_MIN | |
643 | - ARCH_MMAP_RND_COMPAT_BITS_MAX | |
644 | ||
645 | config ARCH_MMAP_RND_COMPAT_BITS_MIN | |
646 | int | |
647 | ||
648 | config ARCH_MMAP_RND_COMPAT_BITS_MAX | |
649 | int | |
650 | ||
651 | config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
652 | int | |
653 | ||
654 | config ARCH_MMAP_RND_COMPAT_BITS | |
655 | int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT | |
656 | range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX | |
657 | default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
658 | default ARCH_MMAP_RND_COMPAT_BITS_MIN | |
659 | depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
660 | help | |
661 | This value can be used to select the number of bits to use to | |
662 | determine the random offset to the base address of vma regions | |
663 | resulting from mmap allocations for compatible applications This | |
664 | value will be bounded by the architecture's minimum and maximum | |
665 | supported values. | |
666 | ||
667 | This value can be changed after boot using the | |
668 | /proc/sys/vm/mmap_rnd_compat_bits tunable | |
669 | ||
1b028f78 DS |
670 | config HAVE_ARCH_COMPAT_MMAP_BASES |
671 | bool | |
672 | help | |
673 | This allows 64bit applications to invoke 32-bit mmap() syscall | |
674 | and vice-versa 32-bit applications to call 64-bit mmap(). | |
675 | Required for applications doing different bitness syscalls. | |
676 | ||
3033f14a JT |
677 | config HAVE_COPY_THREAD_TLS |
678 | bool | |
679 | help | |
680 | Architecture provides copy_thread_tls to accept tls argument via | |
681 | normal C parameter passing, rather than extracting the syscall | |
682 | argument from pt_regs. | |
683 | ||
b9ab5ebb JP |
684 | config HAVE_STACK_VALIDATION |
685 | bool | |
686 | help | |
687 | Architecture supports the 'objtool check' host tool command, which | |
688 | performs compile-time stack metadata validation. | |
689 | ||
af085d90 JP |
690 | config HAVE_RELIABLE_STACKTRACE |
691 | bool | |
692 | help | |
693 | Architecture has a save_stack_trace_tsk_reliable() function which | |
694 | only returns a stack trace if it can guarantee the trace is reliable. | |
695 | ||
468a9428 GS |
696 | config HAVE_ARCH_HASH |
697 | bool | |
698 | default n | |
699 | help | |
700 | If this is set, the architecture provides an <asm/hash.h> | |
701 | file which provides platform-specific implementations of some | |
702 | functions in <linux/hash.h> or fs/namei.c. | |
703 | ||
3a495511 WBG |
704 | config ISA_BUS_API |
705 | def_bool ISA | |
706 | ||
d2125043 AV |
707 | # |
708 | # ABI hall of shame | |
709 | # | |
710 | config CLONE_BACKWARDS | |
711 | bool | |
712 | help | |
713 | Architecture has tls passed as the 4th argument of clone(2), | |
714 | not the 5th one. | |
715 | ||
716 | config CLONE_BACKWARDS2 | |
717 | bool | |
718 | help | |
719 | Architecture has the first two arguments of clone(2) swapped. | |
720 | ||
dfa9771a MS |
721 | config CLONE_BACKWARDS3 |
722 | bool | |
723 | help | |
724 | Architecture has tls passed as the 3rd argument of clone(2), | |
725 | not the 5th one. | |
726 | ||
eaca6eae AV |
727 | config ODD_RT_SIGACTION |
728 | bool | |
729 | help | |
730 | Architecture has unusual rt_sigaction(2) arguments | |
731 | ||
0a0e8cdf AV |
732 | config OLD_SIGSUSPEND |
733 | bool | |
734 | help | |
735 | Architecture has old sigsuspend(2) syscall, of one-argument variety | |
736 | ||
737 | config OLD_SIGSUSPEND3 | |
738 | bool | |
739 | help | |
740 | Even weirder antique ABI - three-argument sigsuspend(2) | |
741 | ||
495dfbf7 AV |
742 | config OLD_SIGACTION |
743 | bool | |
744 | help | |
745 | Architecture has old sigaction(2) syscall. Nope, not the same | |
746 | as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), | |
747 | but fairly different variant of sigaction(2), thanks to OSF/1 | |
748 | compatibility... | |
749 | ||
750 | config COMPAT_OLD_SIGACTION | |
751 | bool | |
752 | ||
d4703dda DD |
753 | config 64BIT_TIME |
754 | def_bool ARCH_HAS_64BIT_TIME | |
755 | help | |
756 | This should be selected by all architectures that need to support | |
757 | new system calls with a 64-bit time_t. This is relevant on all 32-bit | |
758 | architectures, and 64-bit architectures as part of compat syscall | |
759 | handling. | |
760 | ||
17435e5f DD |
761 | config COMPAT_32BIT_TIME |
762 | def_bool (!64BIT && 64BIT_TIME) || COMPAT | |
763 | help | |
764 | This enables 32 bit time_t support in addition to 64 bit time_t support. | |
765 | This is relevant on all 32-bit architectures, and 64-bit architectures | |
766 | as part of compat syscall handling. | |
767 | ||
0d4a619b CH |
768 | config ARCH_NO_COHERENT_DMA_MMAP |
769 | bool | |
770 | ||
87a4c375 CH |
771 | config ARCH_NO_PREEMPT |
772 | bool | |
773 | ||
fff7fb0b ZZ |
774 | config CPU_NO_EFFICIENT_FFS |
775 | def_bool n | |
776 | ||
ba14a194 AL |
777 | config HAVE_ARCH_VMAP_STACK |
778 | def_bool n | |
779 | help | |
780 | An arch should select this symbol if it can support kernel stacks | |
781 | in vmalloc space. This means: | |
782 | ||
783 | - vmalloc space must be large enough to hold many kernel stacks. | |
784 | This may rule out many 32-bit architectures. | |
785 | ||
786 | - Stacks in vmalloc space need to work reliably. For example, if | |
787 | vmap page tables are created on demand, either this mechanism | |
788 | needs to work while the stack points to a virtual address with | |
789 | unpopulated page tables or arch code (switch_to() and switch_mm(), | |
790 | most likely) needs to ensure that the stack's page table entries | |
791 | are populated before running on a possibly unpopulated stack. | |
792 | ||
793 | - If the stack overflows into a guard page, something reasonable | |
794 | should happen. The definition of "reasonable" is flexible, but | |
795 | instantly rebooting without logging anything would be unfriendly. | |
796 | ||
797 | config VMAP_STACK | |
798 | default y | |
799 | bool "Use a virtually-mapped stack" | |
800 | depends on HAVE_ARCH_VMAP_STACK && !KASAN | |
801 | ---help--- | |
802 | Enable this if you want the use virtually-mapped kernel stacks | |
803 | with guard pages. This causes kernel stack overflows to be | |
804 | caught immediately rather than causing difficult-to-diagnose | |
805 | corruption. | |
806 | ||
807 | This is presently incompatible with KASAN because KASAN expects | |
808 | the stack to map directly to the KASAN shadow map using a formula | |
809 | that is incorrect if the stack is in vmalloc space. | |
810 | ||
ad21fc4f LA |
811 | config ARCH_OPTIONAL_KERNEL_RWX |
812 | def_bool n | |
813 | ||
814 | config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
815 | def_bool n | |
816 | ||
817 | config ARCH_HAS_STRICT_KERNEL_RWX | |
818 | def_bool n | |
819 | ||
0f5bf6d0 | 820 | config STRICT_KERNEL_RWX |
ad21fc4f LA |
821 | bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX |
822 | depends on ARCH_HAS_STRICT_KERNEL_RWX | |
823 | default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
824 | help | |
825 | If this is set, kernel text and rodata memory will be made read-only, | |
826 | and non-text memory will be made non-executable. This provides | |
827 | protection against certain security exploits (e.g. executing the heap | |
828 | or modifying text) | |
829 | ||
830 | These features are considered standard security practice these days. | |
831 | You should say Y here in almost all cases. | |
832 | ||
833 | config ARCH_HAS_STRICT_MODULE_RWX | |
834 | def_bool n | |
835 | ||
0f5bf6d0 | 836 | config STRICT_MODULE_RWX |
ad21fc4f LA |
837 | bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX |
838 | depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES | |
839 | default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
840 | help | |
841 | If this is set, module text and rodata memory will be made read-only, | |
842 | and non-text memory will be made non-executable. This provides | |
843 | protection against certain security exploits (e.g. writing to text) | |
844 | ||
ea8c64ac CH |
845 | # select if the architecture provides an asm/dma-direct.h header |
846 | config ARCH_HAS_PHYS_TO_DMA | |
847 | bool | |
848 | ||
7a46ec0e KC |
849 | config ARCH_HAS_REFCOUNT |
850 | bool | |
851 | help | |
852 | An architecture selects this when it has implemented refcount_t | |
853 | using open coded assembly primitives that provide an optimized | |
854 | refcount_t implementation, possibly at the expense of some full | |
855 | refcount state checks of CONFIG_REFCOUNT_FULL=y. | |
856 | ||
857 | The refcount overflow check behavior, however, must be retained. | |
858 | Catching overflows is the primary security concern for protecting | |
859 | against bugs in reference counts. | |
860 | ||
fd25d19f KC |
861 | config REFCOUNT_FULL |
862 | bool "Perform full reference count validation at the expense of speed" | |
863 | help | |
864 | Enabling this switches the refcounting infrastructure from a fast | |
865 | unchecked atomic_t implementation to a fully state checked | |
866 | implementation, which can be (slightly) slower but provides protections | |
867 | against various use-after-free conditions that can be used in | |
868 | security flaw exploits. | |
869 | ||
04f264d3 PB |
870 | config HAVE_ARCH_COMPILER_H |
871 | bool | |
872 | help | |
873 | An architecture can select this if it provides an | |
874 | asm/compiler.h header that should be included after | |
875 | linux/compiler-*.h in order to override macro definitions that those | |
876 | headers generally provide. | |
877 | ||
271ca788 AB |
878 | config HAVE_ARCH_PREL32_RELOCATIONS |
879 | bool | |
880 | help | |
881 | May be selected by an architecture if it supports place-relative | |
882 | 32-bit relocations, both in the toolchain and in the module loader, | |
883 | in which case relative references can be used in special sections | |
884 | for PCI fixup, initcalls etc which are only half the size on 64 bit | |
885 | architectures, and don't require runtime relocation on relocatable | |
886 | kernels. | |
887 | ||
2521f2c2 | 888 | source "kernel/gcov/Kconfig" |
45332b1b MY |
889 | |
890 | source "scripts/gcc-plugins/Kconfig" | |
fa1b5d09 | 891 | |
22471e13 | 892 | endmenu |