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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 | ||
175fca3b SS |
21 | config KEXEC_ELF |
22 | bool | |
23 | ||
467d2782 TJB |
24 | config HAVE_IMA_KEXEC |
25 | bool | |
26 | ||
5e6e9852 CH |
27 | config SET_FS |
28 | bool | |
29 | ||
05736e4a TG |
30 | config HOTPLUG_SMT |
31 | bool | |
32 | ||
142781e1 TG |
33 | config GENERIC_ENTRY |
34 | bool | |
35 | ||
125e5645 MD |
36 | config KPROBES |
37 | bool "Kprobes" | |
05ed160e | 38 | depends on MODULES |
125e5645 | 39 | depends on HAVE_KPROBES |
05ed160e | 40 | select KALLSYMS |
125e5645 MD |
41 | help |
42 | Kprobes allows you to trap at almost any kernel address and | |
43 | execute a callback function. register_kprobe() establishes | |
44 | a probepoint and specifies the callback. Kprobes is useful | |
45 | for kernel debugging, non-intrusive instrumentation and testing. | |
46 | If in doubt, say "N". | |
47 | ||
45f81b1c | 48 | config JUMP_LABEL |
24b54fee KK |
49 | bool "Optimize very unlikely/likely branches" |
50 | depends on HAVE_ARCH_JUMP_LABEL | |
51 | depends on CC_HAS_ASM_GOTO | |
52 | help | |
53 | This option enables a transparent branch optimization that | |
c5905afb IM |
54 | makes certain almost-always-true or almost-always-false branch |
55 | conditions even cheaper to execute within the kernel. | |
56 | ||
57 | Certain performance-sensitive kernel code, such as trace points, | |
58 | scheduler functionality, networking code and KVM have such | |
59 | branches and include support for this optimization technique. | |
60 | ||
24b54fee | 61 | If it is detected that the compiler has support for "asm goto", |
c5905afb IM |
62 | the kernel will compile such branches with just a nop |
63 | instruction. When the condition flag is toggled to true, the | |
64 | nop will be converted to a jump instruction to execute the | |
65 | conditional block of instructions. | |
66 | ||
67 | This technique lowers overhead and stress on the branch prediction | |
68 | of the processor and generally makes the kernel faster. The update | |
69 | of the condition is slower, but those are always very rare. | |
45f81b1c | 70 | |
c5905afb IM |
71 | ( On 32-bit x86, the necessary options added to the compiler |
72 | flags may increase the size of the kernel slightly. ) | |
45f81b1c | 73 | |
1987c947 PZ |
74 | config STATIC_KEYS_SELFTEST |
75 | bool "Static key selftest" | |
76 | depends on JUMP_LABEL | |
77 | help | |
78 | Boot time self-test of the branch patching code. | |
79 | ||
f03c4129 PZ |
80 | config STATIC_CALL_SELFTEST |
81 | bool "Static call selftest" | |
82 | depends on HAVE_STATIC_CALL | |
83 | help | |
84 | Boot time self-test of the call patching code. | |
85 | ||
afd66255 | 86 | config OPTPROBES |
5cc718b9 MH |
87 | def_bool y |
88 | depends on KPROBES && HAVE_OPTPROBES | |
01b1d88b | 89 | select TASKS_RCU if PREEMPTION |
afd66255 | 90 | |
e7dbfe34 MH |
91 | config KPROBES_ON_FTRACE |
92 | def_bool y | |
93 | depends on KPROBES && HAVE_KPROBES_ON_FTRACE | |
94 | depends on DYNAMIC_FTRACE_WITH_REGS | |
95 | help | |
96 | If function tracer is enabled and the arch supports full | |
97 | passing of pt_regs to function tracing, then kprobes can | |
98 | optimize on top of function tracing. | |
99 | ||
2b144498 | 100 | config UPROBES |
09294e31 | 101 | def_bool n |
e8f4aa60 | 102 | depends on ARCH_SUPPORTS_UPROBES |
2b144498 | 103 | help |
7b2d81d4 IM |
104 | Uprobes is the user-space counterpart to kprobes: they |
105 | enable instrumentation applications (such as 'perf probe') | |
106 | to establish unintrusive probes in user-space binaries and | |
107 | libraries, by executing handler functions when the probes | |
108 | are hit by user-space applications. | |
109 | ||
110 | ( These probes come in the form of single-byte breakpoints, | |
111 | managed by the kernel and kept transparent to the probed | |
112 | application. ) | |
2b144498 | 113 | |
adab66b7 SRV |
114 | config HAVE_64BIT_ALIGNED_ACCESS |
115 | def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS | |
116 | help | |
117 | Some architectures require 64 bit accesses to be 64 bit | |
118 | aligned, which also requires structs containing 64 bit values | |
119 | to be 64 bit aligned too. This includes some 32 bit | |
120 | architectures which can do 64 bit accesses, as well as 64 bit | |
121 | architectures without unaligned access. | |
122 | ||
123 | This symbol should be selected by an architecture if 64 bit | |
124 | accesses are required to be 64 bit aligned in this way even | |
125 | though it is not a 64 bit architecture. | |
126 | ||
ba1a297d LB |
127 | See Documentation/core-api/unaligned-memory-access.rst for |
128 | more information on the topic of unaligned memory accesses. | |
adab66b7 | 129 | |
58340a07 | 130 | config HAVE_EFFICIENT_UNALIGNED_ACCESS |
9ba16087 | 131 | bool |
58340a07 JB |
132 | help |
133 | Some architectures are unable to perform unaligned accesses | |
134 | without the use of get_unaligned/put_unaligned. Others are | |
135 | unable to perform such accesses efficiently (e.g. trap on | |
136 | unaligned access and require fixing it up in the exception | |
137 | handler.) | |
138 | ||
139 | This symbol should be selected by an architecture if it can | |
140 | perform unaligned accesses efficiently to allow different | |
141 | code paths to be selected for these cases. Some network | |
142 | drivers, for example, could opt to not fix up alignment | |
143 | problems with received packets if doing so would not help | |
144 | much. | |
145 | ||
c9b54d6f | 146 | See Documentation/core-api/unaligned-memory-access.rst for more |
58340a07 JB |
147 | information on the topic of unaligned memory accesses. |
148 | ||
cf66bb93 | 149 | config ARCH_USE_BUILTIN_BSWAP |
24b54fee KK |
150 | bool |
151 | help | |
cf66bb93 DW |
152 | Modern versions of GCC (since 4.4) have builtin functions |
153 | for handling byte-swapping. Using these, instead of the old | |
154 | inline assembler that the architecture code provides in the | |
155 | __arch_bswapXX() macros, allows the compiler to see what's | |
156 | happening and offers more opportunity for optimisation. In | |
157 | particular, the compiler will be able to combine the byteswap | |
158 | with a nearby load or store and use load-and-swap or | |
159 | store-and-swap instructions if the architecture has them. It | |
160 | should almost *never* result in code which is worse than the | |
161 | hand-coded assembler in <asm/swab.h>. But just in case it | |
162 | does, the use of the builtins is optional. | |
163 | ||
164 | Any architecture with load-and-swap or store-and-swap | |
165 | instructions should set this. And it shouldn't hurt to set it | |
166 | on architectures that don't have such instructions. | |
167 | ||
9edddaa2 AM |
168 | config KRETPROBES |
169 | def_bool y | |
170 | depends on KPROBES && HAVE_KRETPROBES | |
171 | ||
7c68af6e AK |
172 | config USER_RETURN_NOTIFIER |
173 | bool | |
174 | depends on HAVE_USER_RETURN_NOTIFIER | |
175 | help | |
176 | Provide a kernel-internal notification when a cpu is about to | |
177 | switch to user mode. | |
178 | ||
28b2ee20 | 179 | config HAVE_IOREMAP_PROT |
9ba16087 | 180 | bool |
28b2ee20 | 181 | |
125e5645 | 182 | config HAVE_KPROBES |
9ba16087 | 183 | bool |
9edddaa2 AM |
184 | |
185 | config HAVE_KRETPROBES | |
9ba16087 | 186 | bool |
74bc7cee | 187 | |
afd66255 MH |
188 | config HAVE_OPTPROBES |
189 | bool | |
d314d74c | 190 | |
e7dbfe34 MH |
191 | config HAVE_KPROBES_ON_FTRACE |
192 | bool | |
193 | ||
540adea3 | 194 | config HAVE_FUNCTION_ERROR_INJECTION |
9802d865 JB |
195 | bool |
196 | ||
42a0bb3f PM |
197 | config HAVE_NMI |
198 | bool | |
199 | ||
4aae683f MY |
200 | config TRACE_IRQFLAGS_SUPPORT |
201 | bool | |
202 | ||
1f5a4ad9 RM |
203 | # |
204 | # An arch should select this if it provides all these things: | |
205 | # | |
206 | # task_pt_regs() in asm/processor.h or asm/ptrace.h | |
207 | # arch_has_single_step() if there is hardware single-step support | |
208 | # arch_has_block_step() if there is hardware block-step support | |
1f5a4ad9 RM |
209 | # asm/syscall.h supplying asm-generic/syscall.h interface |
210 | # linux/regset.h user_regset interfaces | |
211 | # CORE_DUMP_USE_REGSET #define'd in linux/elf.h | |
212 | # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} | |
213 | # TIF_NOTIFY_RESUME calls tracehook_notify_resume() | |
214 | # signal delivery calls tracehook_signal_handler() | |
215 | # | |
216 | config HAVE_ARCH_TRACEHOOK | |
9ba16087 | 217 | bool |
1f5a4ad9 | 218 | |
c64be2bb MS |
219 | config HAVE_DMA_CONTIGUOUS |
220 | bool | |
221 | ||
29d5e047 | 222 | config GENERIC_SMP_IDLE_THREAD |
24b54fee | 223 | bool |
29d5e047 | 224 | |
485cf5da | 225 | config GENERIC_IDLE_POLL_SETUP |
24b54fee | 226 | bool |
485cf5da | 227 | |
6974f0c4 DM |
228 | config ARCH_HAS_FORTIFY_SOURCE |
229 | bool | |
230 | help | |
231 | An architecture should select this when it can successfully | |
232 | build and run with CONFIG_FORTIFY_SOURCE. | |
233 | ||
d8ae8a37 CH |
234 | # |
235 | # Select if the arch provides a historic keepinit alias for the retain_initrd | |
236 | # command line option | |
237 | # | |
238 | config ARCH_HAS_KEEPINITRD | |
239 | bool | |
240 | ||
d2852a22 DB |
241 | # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h |
242 | config ARCH_HAS_SET_MEMORY | |
243 | bool | |
244 | ||
d253ca0c RE |
245 | # Select if arch has all set_direct_map_invalid/default() functions |
246 | config ARCH_HAS_SET_DIRECT_MAP | |
247 | bool | |
248 | ||
c30700db | 249 | # |
fa7e2247 | 250 | # Select if the architecture provides the arch_dma_set_uncached symbol to |
a86ecfa6 | 251 | # either provide an uncached segment alias for a DMA allocation, or |
fa7e2247 | 252 | # to remap the page tables in place. |
c30700db | 253 | # |
fa7e2247 | 254 | config ARCH_HAS_DMA_SET_UNCACHED |
c30700db CH |
255 | bool |
256 | ||
999a5d12 CH |
257 | # |
258 | # Select if the architectures provides the arch_dma_clear_uncached symbol | |
259 | # to undo an in-place page table remap for uncached access. | |
260 | # | |
261 | config ARCH_HAS_DMA_CLEAR_UNCACHED | |
c30700db CH |
262 | bool |
263 | ||
0500871f DH |
264 | # Select if arch init_task must go in the __init_task_data section |
265 | config ARCH_TASK_STRUCT_ON_STACK | |
24b54fee | 266 | bool |
a4a2eb49 | 267 | |
f5e10287 TG |
268 | # Select if arch has its private alloc_task_struct() function |
269 | config ARCH_TASK_STRUCT_ALLOCATOR | |
270 | bool | |
271 | ||
5905429a KC |
272 | config HAVE_ARCH_THREAD_STRUCT_WHITELIST |
273 | bool | |
274 | depends on !ARCH_TASK_STRUCT_ALLOCATOR | |
275 | help | |
276 | An architecture should select this to provide hardened usercopy | |
277 | knowledge about what region of the thread_struct should be | |
278 | whitelisted for copying to userspace. Normally this is only the | |
279 | FPU registers. Specifically, arch_thread_struct_whitelist() | |
280 | should be implemented. Without this, the entire thread_struct | |
281 | field in task_struct will be left whitelisted. | |
282 | ||
b235beea LT |
283 | # Select if arch has its private alloc_thread_stack() function |
284 | config ARCH_THREAD_STACK_ALLOCATOR | |
f5e10287 TG |
285 | bool |
286 | ||
5aaeb5c0 IM |
287 | # Select if arch wants to size task_struct dynamically via arch_task_struct_size: |
288 | config ARCH_WANTS_DYNAMIC_TASK_STRUCT | |
289 | bool | |
290 | ||
51c2ee6d ND |
291 | config ARCH_WANTS_NO_INSTR |
292 | bool | |
293 | help | |
294 | An architecture should select this if the noinstr macro is being used on | |
295 | functions to denote that the toolchain should avoid instrumenting such | |
296 | functions and is required for correctness. | |
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 | ||
96c0a6a7 HC |
308 | # Selected by 64 bit architectures which have a 32 bit f_tinode in struct ustat |
309 | config ARCH_32BIT_USTAT_F_TINODE | |
310 | bool | |
311 | ||
2ff2b7ec MY |
312 | config HAVE_ASM_MODVERSIONS |
313 | bool | |
314 | help | |
a86ecfa6 | 315 | This symbol should be selected by an architecture if it provides |
2ff2b7ec MY |
316 | <asm/asm-prototypes.h> to support the module versioning for symbols |
317 | exported from assembly code. | |
318 | ||
f850c30c HC |
319 | config HAVE_REGS_AND_STACK_ACCESS_API |
320 | bool | |
e01292b1 | 321 | help |
a86ecfa6 | 322 | This symbol should be selected by an architecture if it supports |
e01292b1 HC |
323 | the API needed to access registers and stack entries from pt_regs, |
324 | declared in asm/ptrace.h | |
325 | For example the kprobes-based event tracer needs this API. | |
f850c30c | 326 | |
d7822b1e MD |
327 | config HAVE_RSEQ |
328 | bool | |
329 | depends on HAVE_REGS_AND_STACK_ACCESS_API | |
330 | help | |
331 | This symbol should be selected by an architecture if it | |
332 | supports an implementation of restartable sequences. | |
333 | ||
3c88ee19 MH |
334 | config HAVE_FUNCTION_ARG_ACCESS_API |
335 | bool | |
336 | help | |
a86ecfa6 | 337 | This symbol should be selected by an architecture if it supports |
3c88ee19 MH |
338 | the API needed to access function arguments from pt_regs, |
339 | declared in asm/ptrace.h | |
340 | ||
62a038d3 P |
341 | config HAVE_HW_BREAKPOINT |
342 | bool | |
99e8c5a3 | 343 | depends on PERF_EVENTS |
62a038d3 | 344 | |
0102752e FW |
345 | config HAVE_MIXED_BREAKPOINTS_REGS |
346 | bool | |
347 | depends on HAVE_HW_BREAKPOINT | |
348 | help | |
349 | Depending on the arch implementation of hardware breakpoints, | |
350 | some of them have separate registers for data and instruction | |
351 | breakpoints addresses, others have mixed registers to store | |
352 | them but define the access type in a control register. | |
353 | Select this option if your arch implements breakpoints under the | |
354 | latter fashion. | |
355 | ||
7c68af6e AK |
356 | config HAVE_USER_RETURN_NOTIFIER |
357 | bool | |
a1922ed6 | 358 | |
c01d4323 FW |
359 | config HAVE_PERF_EVENTS_NMI |
360 | bool | |
23637d47 FW |
361 | help |
362 | System hardware can generate an NMI using the perf event | |
363 | subsystem. Also has support for calculating CPU cycle events | |
364 | to determine how many clock cycles in a given period. | |
c01d4323 | 365 | |
05a4a952 NP |
366 | config HAVE_HARDLOCKUP_DETECTOR_PERF |
367 | bool | |
368 | depends on HAVE_PERF_EVENTS_NMI | |
369 | help | |
370 | The arch chooses to use the generic perf-NMI-based hardlockup | |
371 | detector. Must define HAVE_PERF_EVENTS_NMI. | |
372 | ||
373 | config HAVE_NMI_WATCHDOG | |
374 | depends on HAVE_NMI | |
375 | bool | |
376 | help | |
377 | The arch provides a low level NMI watchdog. It provides | |
378 | asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). | |
379 | ||
380 | config HAVE_HARDLOCKUP_DETECTOR_ARCH | |
381 | bool | |
382 | select HAVE_NMI_WATCHDOG | |
383 | help | |
384 | The arch chooses to provide its own hardlockup detector, which is | |
385 | a superset of the HAVE_NMI_WATCHDOG. It also conforms to config | |
386 | interfaces and parameters provided by hardlockup detector subsystem. | |
387 | ||
c5e63197 JO |
388 | config HAVE_PERF_REGS |
389 | bool | |
390 | help | |
391 | Support selective register dumps for perf events. This includes | |
392 | bit-mapping of each registers and a unique architecture id. | |
393 | ||
c5ebcedb JO |
394 | config HAVE_PERF_USER_STACK_DUMP |
395 | bool | |
396 | help | |
397 | Support user stack dumps for perf event samples. This needs | |
398 | access to the user stack pointer which is not unified across | |
399 | architectures. | |
400 | ||
bf5438fc JB |
401 | config HAVE_ARCH_JUMP_LABEL |
402 | bool | |
403 | ||
50ff18ab AB |
404 | config HAVE_ARCH_JUMP_LABEL_RELATIVE |
405 | bool | |
406 | ||
0d6e24d4 PZ |
407 | config MMU_GATHER_TABLE_FREE |
408 | bool | |
409 | ||
ff2e6d72 | 410 | config MMU_GATHER_RCU_TABLE_FREE |
26723911 | 411 | bool |
0d6e24d4 | 412 | select MMU_GATHER_TABLE_FREE |
26723911 | 413 | |
3af4bd03 | 414 | config MMU_GATHER_PAGE_SIZE |
ed6a7935 PZ |
415 | bool |
416 | ||
27796d03 PZ |
417 | config MMU_GATHER_NO_RANGE |
418 | bool | |
419 | ||
580a586c | 420 | config MMU_GATHER_NO_GATHER |
952a31c9 | 421 | bool |
0d6e24d4 | 422 | depends on MMU_GATHER_TABLE_FREE |
952a31c9 | 423 | |
d53c3dfb NP |
424 | config ARCH_WANT_IRQS_OFF_ACTIVATE_MM |
425 | bool | |
426 | help | |
427 | Temporary select until all architectures can be converted to have | |
428 | irqs disabled over activate_mm. Architectures that do IPI based TLB | |
429 | shootdowns should enable this. | |
430 | ||
df013ffb HY |
431 | config ARCH_HAVE_NMI_SAFE_CMPXCHG |
432 | bool | |
433 | ||
43570fd2 HC |
434 | config HAVE_ALIGNED_STRUCT_PAGE |
435 | bool | |
436 | help | |
437 | This makes sure that struct pages are double word aligned and that | |
438 | e.g. the SLUB allocator can perform double word atomic operations | |
439 | on a struct page for better performance. However selecting this | |
440 | might increase the size of a struct page by a word. | |
441 | ||
4156153c HC |
442 | config HAVE_CMPXCHG_LOCAL |
443 | bool | |
444 | ||
2565409f HC |
445 | config HAVE_CMPXCHG_DOUBLE |
446 | bool | |
447 | ||
77e58496 PM |
448 | config ARCH_WEAK_RELEASE_ACQUIRE |
449 | bool | |
450 | ||
c1d7e01d WD |
451 | config ARCH_WANT_IPC_PARSE_VERSION |
452 | bool | |
453 | ||
454 | config ARCH_WANT_COMPAT_IPC_PARSE_VERSION | |
455 | bool | |
456 | ||
48b25c43 | 457 | config ARCH_WANT_OLD_COMPAT_IPC |
c1d7e01d | 458 | select ARCH_WANT_COMPAT_IPC_PARSE_VERSION |
48b25c43 CM |
459 | bool |
460 | ||
282a181b YZ |
461 | config HAVE_ARCH_SECCOMP |
462 | bool | |
463 | help | |
464 | An arch should select this symbol to support seccomp mode 1 (the fixed | |
465 | syscall policy), and must provide an overrides for __NR_seccomp_sigreturn, | |
466 | and compat syscalls if the asm-generic/seccomp.h defaults need adjustment: | |
467 | - __NR_seccomp_read_32 | |
468 | - __NR_seccomp_write_32 | |
469 | - __NR_seccomp_exit_32 | |
470 | - __NR_seccomp_sigreturn_32 | |
471 | ||
e2cfabdf WD |
472 | config HAVE_ARCH_SECCOMP_FILTER |
473 | bool | |
282a181b | 474 | select HAVE_ARCH_SECCOMP |
e2cfabdf | 475 | help |
fb0fadf9 | 476 | An arch should select this symbol if it provides all of these things: |
282a181b | 477 | - all the requirements for HAVE_ARCH_SECCOMP |
bb6ea430 WD |
478 | - syscall_get_arch() |
479 | - syscall_get_arguments() | |
480 | - syscall_rollback() | |
481 | - syscall_set_return_value() | |
fb0fadf9 WD |
482 | - SIGSYS siginfo_t support |
483 | - secure_computing is called from a ptrace_event()-safe context | |
484 | - secure_computing return value is checked and a return value of -1 | |
485 | results in the system call being skipped immediately. | |
48dc92b9 | 486 | - seccomp syscall wired up |
0d8315dd YZ |
487 | - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE, |
488 | SECCOMP_ARCH_NATIVE_NR, SECCOMP_ARCH_NATIVE_NAME defined. If | |
489 | COMPAT is supported, have the SECCOMP_ARCH_COMPAT* defines too. | |
e2cfabdf | 490 | |
282a181b YZ |
491 | config SECCOMP |
492 | prompt "Enable seccomp to safely execute untrusted bytecode" | |
493 | def_bool y | |
494 | depends on HAVE_ARCH_SECCOMP | |
495 | help | |
496 | This kernel feature is useful for number crunching applications | |
497 | that may need to handle untrusted bytecode during their | |
498 | execution. By using pipes or other transports made available | |
499 | to the process as file descriptors supporting the read/write | |
500 | syscalls, it's possible to isolate those applications in their | |
501 | own address space using seccomp. Once seccomp is enabled via | |
502 | prctl(PR_SET_SECCOMP) or the seccomp() syscall, it cannot be | |
503 | disabled and the task is only allowed to execute a few safe | |
504 | syscalls defined by each seccomp mode. | |
505 | ||
506 | If unsure, say Y. | |
507 | ||
e2cfabdf WD |
508 | config SECCOMP_FILTER |
509 | def_bool y | |
510 | depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET | |
511 | help | |
512 | Enable tasks to build secure computing environments defined | |
513 | in terms of Berkeley Packet Filter programs which implement | |
514 | task-defined system call filtering polices. | |
515 | ||
5fb94e9c | 516 | See Documentation/userspace-api/seccomp_filter.rst for details. |
e2cfabdf | 517 | |
0d8315dd YZ |
518 | config SECCOMP_CACHE_DEBUG |
519 | bool "Show seccomp filter cache status in /proc/pid/seccomp_cache" | |
520 | depends on SECCOMP_FILTER && !HAVE_SPARSE_SYSCALL_NR | |
521 | depends on PROC_FS | |
522 | help | |
523 | This enables the /proc/pid/seccomp_cache interface to monitor | |
524 | seccomp cache data. The file format is subject to change. Reading | |
525 | the file requires CAP_SYS_ADMIN. | |
526 | ||
527 | This option is for debugging only. Enabling presents the risk that | |
528 | an adversary may be able to infer the seccomp filter logic. | |
529 | ||
530 | If unsure, say N. | |
531 | ||
afaef01c AP |
532 | config HAVE_ARCH_STACKLEAK |
533 | bool | |
534 | help | |
535 | An architecture should select this if it has the code which | |
536 | fills the used part of the kernel stack with the STACKLEAK_POISON | |
537 | value before returning from system calls. | |
538 | ||
d148eac0 | 539 | config HAVE_STACKPROTECTOR |
19952a92 KC |
540 | bool |
541 | help | |
542 | An arch should select this symbol if: | |
19952a92 KC |
543 | - it has implemented a stack canary (e.g. __stack_chk_guard) |
544 | ||
050e9baa | 545 | config STACKPROTECTOR |
2a61f474 | 546 | bool "Stack Protector buffer overflow detection" |
d148eac0 | 547 | depends on HAVE_STACKPROTECTOR |
2a61f474 MY |
548 | depends on $(cc-option,-fstack-protector) |
549 | default y | |
19952a92 | 550 | help |
8779657d | 551 | This option turns on the "stack-protector" GCC feature. This |
19952a92 KC |
552 | feature puts, at the beginning of functions, a canary value on |
553 | the stack just before the return address, and validates | |
554 | the value just before actually returning. Stack based buffer | |
555 | overflows (that need to overwrite this return address) now also | |
556 | overwrite the canary, which gets detected and the attack is then | |
557 | neutralized via a kernel panic. | |
558 | ||
8779657d KC |
559 | Functions will have the stack-protector canary logic added if they |
560 | have an 8-byte or larger character array on the stack. | |
561 | ||
19952a92 | 562 | This feature requires gcc version 4.2 or above, or a distribution |
8779657d KC |
563 | gcc with the feature backported ("-fstack-protector"). |
564 | ||
565 | On an x86 "defconfig" build, this feature adds canary checks to | |
566 | about 3% of all kernel functions, which increases kernel code size | |
567 | by about 0.3%. | |
568 | ||
050e9baa | 569 | config STACKPROTECTOR_STRONG |
2a61f474 | 570 | bool "Strong Stack Protector" |
050e9baa | 571 | depends on STACKPROTECTOR |
2a61f474 MY |
572 | depends on $(cc-option,-fstack-protector-strong) |
573 | default y | |
8779657d KC |
574 | help |
575 | Functions will have the stack-protector canary logic added in any | |
576 | of the following conditions: | |
577 | ||
578 | - local variable's address used as part of the right hand side of an | |
579 | assignment or function argument | |
580 | - local variable is an array (or union containing an array), | |
581 | regardless of array type or length | |
582 | - uses register local variables | |
583 | ||
584 | This feature requires gcc version 4.9 or above, or a distribution | |
585 | gcc with the feature backported ("-fstack-protector-strong"). | |
586 | ||
587 | On an x86 "defconfig" build, this feature adds canary checks to | |
588 | about 20% of all kernel functions, which increases the kernel code | |
589 | size by about 2%. | |
590 | ||
d08b9f0c ST |
591 | config ARCH_SUPPORTS_SHADOW_CALL_STACK |
592 | bool | |
593 | help | |
594 | An architecture should select this if it supports Clang's Shadow | |
aa7a65ae WD |
595 | Call Stack and implements runtime support for shadow stack |
596 | switching. | |
d08b9f0c ST |
597 | |
598 | config SHADOW_CALL_STACK | |
599 | bool "Clang Shadow Call Stack" | |
600 | depends on CC_IS_CLANG && ARCH_SUPPORTS_SHADOW_CALL_STACK | |
ddc9863e | 601 | depends on DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER |
d08b9f0c ST |
602 | help |
603 | This option enables Clang's Shadow Call Stack, which uses a | |
604 | shadow stack to protect function return addresses from being | |
605 | overwritten by an attacker. More information can be found in | |
606 | Clang's documentation: | |
607 | ||
608 | https://clang.llvm.org/docs/ShadowCallStack.html | |
609 | ||
610 | Note that security guarantees in the kernel differ from the | |
611 | ones documented for user space. The kernel must store addresses | |
612 | of shadow stacks in memory, which means an attacker capable of | |
613 | reading and writing arbitrary memory may be able to locate them | |
614 | and hijack control flow by modifying the stacks. | |
615 | ||
dc5723b0 ST |
616 | config LTO |
617 | bool | |
618 | help | |
619 | Selected if the kernel will be built using the compiler's LTO feature. | |
620 | ||
621 | config LTO_CLANG | |
622 | bool | |
623 | select LTO | |
624 | help | |
625 | Selected if the kernel will be built using Clang's LTO feature. | |
626 | ||
627 | config ARCH_SUPPORTS_LTO_CLANG | |
628 | bool | |
629 | help | |
630 | An architecture should select this option if it supports: | |
631 | - compiling with Clang, | |
632 | - compiling inline assembly with Clang's integrated assembler, | |
633 | - and linking with LLD. | |
634 | ||
635 | config ARCH_SUPPORTS_LTO_CLANG_THIN | |
636 | bool | |
637 | help | |
638 | An architecture should select this option if it can support Clang's | |
639 | ThinLTO mode. | |
640 | ||
641 | config HAS_LTO_CLANG | |
642 | def_bool y | |
643 | # Clang >= 11: https://github.com/ClangBuiltLinux/linux/issues/510 | |
ba64beb1 | 644 | depends on CC_IS_CLANG && CLANG_VERSION >= 110000 && LD_IS_LLD && AS_IS_LLVM |
dc5723b0 ST |
645 | depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm) |
646 | depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm) | |
647 | depends on ARCH_SUPPORTS_LTO_CLANG | |
648 | depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT | |
bf3c2551 | 649 | depends on !KASAN || KASAN_HW_TAGS |
dc5723b0 | 650 | depends on !GCOV_KERNEL |
dc5723b0 ST |
651 | help |
652 | The compiler and Kconfig options support building with Clang's | |
653 | LTO. | |
654 | ||
655 | choice | |
656 | prompt "Link Time Optimization (LTO)" | |
657 | default LTO_NONE | |
658 | help | |
659 | This option enables Link Time Optimization (LTO), which allows the | |
660 | compiler to optimize binaries globally. | |
661 | ||
662 | If unsure, select LTO_NONE. Note that LTO is very resource-intensive | |
663 | so it's disabled by default. | |
664 | ||
665 | config LTO_NONE | |
666 | bool "None" | |
667 | help | |
668 | Build the kernel normally, without Link Time Optimization (LTO). | |
669 | ||
670 | config LTO_CLANG_FULL | |
671 | bool "Clang Full LTO (EXPERIMENTAL)" | |
672 | depends on HAS_LTO_CLANG | |
673 | depends on !COMPILE_TEST | |
674 | select LTO_CLANG | |
675 | help | |
676 | This option enables Clang's full Link Time Optimization (LTO), which | |
677 | allows the compiler to optimize the kernel globally. If you enable | |
678 | this option, the compiler generates LLVM bitcode instead of ELF | |
679 | object files, and the actual compilation from bitcode happens at | |
680 | the LTO link step, which may take several minutes depending on the | |
681 | kernel configuration. More information can be found from LLVM's | |
682 | documentation: | |
683 | ||
684 | https://llvm.org/docs/LinkTimeOptimization.html | |
685 | ||
686 | During link time, this option can use a large amount of RAM, and | |
687 | may take much longer than the ThinLTO option. | |
688 | ||
689 | config LTO_CLANG_THIN | |
690 | bool "Clang ThinLTO (EXPERIMENTAL)" | |
691 | depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN | |
692 | select LTO_CLANG | |
693 | help | |
694 | This option enables Clang's ThinLTO, which allows for parallel | |
695 | optimization and faster incremental compiles compared to the | |
696 | CONFIG_LTO_CLANG_FULL option. More information can be found | |
697 | from Clang's documentation: | |
698 | ||
699 | https://clang.llvm.org/docs/ThinLTO.html | |
700 | ||
701 | If unsure, say Y. | |
702 | endchoice | |
703 | ||
cf68fffb ST |
704 | config ARCH_SUPPORTS_CFI_CLANG |
705 | bool | |
706 | help | |
707 | An architecture should select this option if it can support Clang's | |
708 | Control-Flow Integrity (CFI) checking. | |
709 | ||
710 | config CFI_CLANG | |
711 | bool "Use Clang's Control Flow Integrity (CFI)" | |
712 | depends on LTO_CLANG && ARCH_SUPPORTS_CFI_CLANG | |
713 | # Clang >= 12: | |
714 | # - https://bugs.llvm.org/show_bug.cgi?id=46258 | |
715 | # - https://bugs.llvm.org/show_bug.cgi?id=47479 | |
716 | depends on CLANG_VERSION >= 120000 | |
717 | select KALLSYMS | |
718 | help | |
719 | This option enables Clang’s forward-edge Control Flow Integrity | |
720 | (CFI) checking, where the compiler injects a runtime check to each | |
721 | indirect function call to ensure the target is a valid function with | |
722 | the correct static type. This restricts possible call targets and | |
723 | makes it more difficult for an attacker to exploit bugs that allow | |
724 | the modification of stored function pointers. More information can be | |
725 | found from Clang's documentation: | |
726 | ||
727 | https://clang.llvm.org/docs/ControlFlowIntegrity.html | |
728 | ||
729 | config CFI_CLANG_SHADOW | |
730 | bool "Use CFI shadow to speed up cross-module checks" | |
731 | default y | |
732 | depends on CFI_CLANG && MODULES | |
733 | help | |
734 | If you select this option, the kernel builds a fast look-up table of | |
735 | CFI check functions in loaded modules to reduce performance overhead. | |
736 | ||
737 | If unsure, say Y. | |
738 | ||
739 | config CFI_PERMISSIVE | |
740 | bool "Use CFI in permissive mode" | |
741 | depends on CFI_CLANG | |
742 | help | |
743 | When selected, Control Flow Integrity (CFI) violations result in a | |
744 | warning instead of a kernel panic. This option should only be used | |
745 | for finding indirect call type mismatches during development. | |
746 | ||
747 | If unsure, say N. | |
748 | ||
0f60a8ef KC |
749 | config HAVE_ARCH_WITHIN_STACK_FRAMES |
750 | bool | |
751 | help | |
752 | An architecture should select this if it can walk the kernel stack | |
753 | frames to determine if an object is part of either the arguments | |
754 | or local variables (i.e. that it excludes saved return addresses, | |
755 | and similar) by implementing an inline arch_within_stack_frames(), | |
756 | which is used by CONFIG_HARDENED_USERCOPY. | |
757 | ||
91d1aa43 | 758 | config HAVE_CONTEXT_TRACKING |
2b1d5024 FW |
759 | bool |
760 | help | |
91d1aa43 FW |
761 | Provide kernel/user boundaries probes necessary for subsystems |
762 | that need it, such as userspace RCU extended quiescent state. | |
490f561b FW |
763 | Syscalls need to be wrapped inside user_exit()-user_enter(), either |
764 | optimized behind static key or through the slow path using TIF_NOHZ | |
765 | flag. Exceptions handlers must be wrapped as well. Irqs are already | |
766 | protected inside rcu_irq_enter/rcu_irq_exit() but preemption or signal | |
767 | handling on irq exit still need to be protected. | |
768 | ||
83c2da2e FW |
769 | config HAVE_CONTEXT_TRACKING_OFFSTACK |
770 | bool | |
771 | help | |
772 | Architecture neither relies on exception_enter()/exception_exit() | |
773 | nor on schedule_user(). Also preempt_schedule_notrace() and | |
774 | preempt_schedule_irq() can't be called in a preemptible section | |
775 | while context tracking is CONTEXT_USER. This feature reflects a sane | |
776 | entry implementation where the following requirements are met on | |
777 | critical entry code, ie: before user_exit() or after user_enter(): | |
778 | ||
779 | - Critical entry code isn't preemptible (or better yet: | |
780 | not interruptible). | |
781 | - No use of RCU read side critical sections, unless rcu_nmi_enter() | |
782 | got called. | |
783 | - No use of instrumentation, unless instrumentation_begin() got | |
784 | called. | |
785 | ||
490f561b FW |
786 | config HAVE_TIF_NOHZ |
787 | bool | |
788 | help | |
789 | Arch relies on TIF_NOHZ and syscall slow path to implement context | |
790 | tracking calls to user_enter()/user_exit(). | |
2b1d5024 | 791 | |
b952741c FW |
792 | config HAVE_VIRT_CPU_ACCOUNTING |
793 | bool | |
794 | ||
2b91ec9f FW |
795 | config HAVE_VIRT_CPU_ACCOUNTING_IDLE |
796 | bool | |
797 | help | |
798 | Architecture has its own way to account idle CPU time and therefore | |
799 | doesn't implement vtime_account_idle(). | |
800 | ||
40565b5a SG |
801 | config ARCH_HAS_SCALED_CPUTIME |
802 | bool | |
803 | ||
554b0004 KH |
804 | config HAVE_VIRT_CPU_ACCOUNTING_GEN |
805 | bool | |
806 | default y if 64BIT | |
807 | help | |
808 | With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. | |
809 | Before enabling this option, arch code must be audited | |
810 | to ensure there are no races in concurrent read/write of | |
811 | cputime_t. For example, reading/writing 64-bit cputime_t on | |
812 | some 32-bit arches may require multiple accesses, so proper | |
813 | locking is needed to protect against concurrent accesses. | |
814 | ||
fdf9c356 FW |
815 | config HAVE_IRQ_TIME_ACCOUNTING |
816 | bool | |
817 | help | |
818 | Archs need to ensure they use a high enough resolution clock to | |
819 | support irq time accounting and then call enable_sched_clock_irqtime(). | |
820 | ||
c49dd340 KS |
821 | config HAVE_MOVE_PUD |
822 | bool | |
823 | help | |
824 | Architectures that select this are able to move page tables at the | |
825 | PUD level. If there are only 3 page table levels, the move effectively | |
826 | happens at the PGD level. | |
827 | ||
2c91bd4a JFG |
828 | config HAVE_MOVE_PMD |
829 | bool | |
830 | help | |
831 | Archs that select this are able to move page tables at the PMD level. | |
832 | ||
15626062 GS |
833 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE |
834 | bool | |
835 | ||
a00cc7d9 MW |
836 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
837 | bool | |
838 | ||
0ddab1d2 TK |
839 | config HAVE_ARCH_HUGE_VMAP |
840 | bool | |
841 | ||
121e6f32 NP |
842 | # |
843 | # Archs that select this would be capable of PMD-sized vmaps (i.e., | |
844 | # arch_vmap_pmd_supported() returns true), and they must make no assumptions | |
845 | # that vmalloc memory is mapped with PAGE_SIZE ptes. The VM_NO_HUGE_VMAP flag | |
846 | # can be used to prohibit arch-specific allocations from using hugepages to | |
847 | # help with this (e.g., modules may require it). | |
848 | # | |
849 | config HAVE_ARCH_HUGE_VMALLOC | |
850 | depends on HAVE_ARCH_HUGE_VMAP | |
851 | bool | |
852 | ||
3876d4a3 AG |
853 | config ARCH_WANT_HUGE_PMD_SHARE |
854 | bool | |
855 | ||
0f8975ec PE |
856 | config HAVE_ARCH_SOFT_DIRTY |
857 | bool | |
858 | ||
786d35d4 DH |
859 | config HAVE_MOD_ARCH_SPECIFIC |
860 | bool | |
861 | help | |
862 | The arch uses struct mod_arch_specific to store data. Many arches | |
863 | just need a simple module loader without arch specific data - those | |
864 | should not enable this. | |
865 | ||
866 | config MODULES_USE_ELF_RELA | |
867 | bool | |
868 | help | |
869 | Modules only use ELF RELA relocations. Modules with ELF REL | |
870 | relocations will give an error. | |
871 | ||
872 | config MODULES_USE_ELF_REL | |
873 | bool | |
874 | help | |
875 | Modules only use ELF REL relocations. Modules with ELF RELA | |
876 | relocations will give an error. | |
877 | ||
cc1f0274 FW |
878 | config HAVE_IRQ_EXIT_ON_IRQ_STACK |
879 | bool | |
880 | help | |
881 | Architecture doesn't only execute the irq handler on the irq stack | |
882 | but also irq_exit(). This way we can process softirqs on this irq | |
883 | stack instead of switching to a new one when we call __do_softirq() | |
884 | in the end of an hardirq. | |
885 | This spares a stack switch and improves cache usage on softirq | |
886 | processing. | |
887 | ||
cd1a41ce TG |
888 | config HAVE_SOFTIRQ_ON_OWN_STACK |
889 | bool | |
890 | help | |
891 | Architecture provides a function to run __do_softirq() on a | |
c226bc3c | 892 | separate stack. |
cd1a41ce | 893 | |
235a8f02 KS |
894 | config PGTABLE_LEVELS |
895 | int | |
896 | default 2 | |
897 | ||
2b68f6ca KC |
898 | config ARCH_HAS_ELF_RANDOMIZE |
899 | bool | |
900 | help | |
901 | An architecture supports choosing randomized locations for | |
902 | stack, mmap, brk, and ET_DYN. Defined functions: | |
903 | - arch_mmap_rnd() | |
204db6ed | 904 | - arch_randomize_brk() |
2b68f6ca | 905 | |
d07e2259 DC |
906 | config HAVE_ARCH_MMAP_RND_BITS |
907 | bool | |
908 | help | |
909 | An arch should select this symbol if it supports setting a variable | |
910 | number of bits for use in establishing the base address for mmap | |
911 | allocations, has MMU enabled and provides values for both: | |
912 | - ARCH_MMAP_RND_BITS_MIN | |
913 | - ARCH_MMAP_RND_BITS_MAX | |
914 | ||
5f56a5df JS |
915 | config HAVE_EXIT_THREAD |
916 | bool | |
917 | help | |
918 | An architecture implements exit_thread. | |
919 | ||
d07e2259 DC |
920 | config ARCH_MMAP_RND_BITS_MIN |
921 | int | |
922 | ||
923 | config ARCH_MMAP_RND_BITS_MAX | |
924 | int | |
925 | ||
926 | config ARCH_MMAP_RND_BITS_DEFAULT | |
927 | int | |
928 | ||
929 | config ARCH_MMAP_RND_BITS | |
930 | int "Number of bits to use for ASLR of mmap base address" if EXPERT | |
931 | range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX | |
932 | default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT | |
933 | default ARCH_MMAP_RND_BITS_MIN | |
934 | depends on HAVE_ARCH_MMAP_RND_BITS | |
935 | help | |
936 | This value can be used to select the number of bits to use to | |
937 | determine the random offset to the base address of vma regions | |
938 | resulting from mmap allocations. This value will be bounded | |
939 | by the architecture's minimum and maximum supported values. | |
940 | ||
941 | This value can be changed after boot using the | |
942 | /proc/sys/vm/mmap_rnd_bits tunable | |
943 | ||
944 | config HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
945 | bool | |
946 | help | |
947 | An arch should select this symbol if it supports running applications | |
948 | in compatibility mode, supports setting a variable number of bits for | |
949 | use in establishing the base address for mmap allocations, has MMU | |
950 | enabled and provides values for both: | |
951 | - ARCH_MMAP_RND_COMPAT_BITS_MIN | |
952 | - ARCH_MMAP_RND_COMPAT_BITS_MAX | |
953 | ||
954 | config ARCH_MMAP_RND_COMPAT_BITS_MIN | |
955 | int | |
956 | ||
957 | config ARCH_MMAP_RND_COMPAT_BITS_MAX | |
958 | int | |
959 | ||
960 | config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
961 | int | |
962 | ||
963 | config ARCH_MMAP_RND_COMPAT_BITS | |
964 | int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT | |
965 | range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX | |
966 | default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
967 | default ARCH_MMAP_RND_COMPAT_BITS_MIN | |
968 | depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
969 | help | |
970 | This value can be used to select the number of bits to use to | |
971 | determine the random offset to the base address of vma regions | |
972 | resulting from mmap allocations for compatible applications This | |
973 | value will be bounded by the architecture's minimum and maximum | |
974 | supported values. | |
975 | ||
976 | This value can be changed after boot using the | |
977 | /proc/sys/vm/mmap_rnd_compat_bits tunable | |
978 | ||
1b028f78 DS |
979 | config HAVE_ARCH_COMPAT_MMAP_BASES |
980 | bool | |
981 | help | |
982 | This allows 64bit applications to invoke 32-bit mmap() syscall | |
983 | and vice-versa 32-bit applications to call 64-bit mmap(). | |
984 | Required for applications doing different bitness syscalls. | |
985 | ||
67f3977f AG |
986 | # This allows to use a set of generic functions to determine mmap base |
987 | # address by giving priority to top-down scheme only if the process | |
988 | # is not in legacy mode (compat task, unlimited stack size or | |
989 | # sysctl_legacy_va_layout). | |
990 | # Architecture that selects this option can provide its own version of: | |
991 | # - STACK_RND_MASK | |
992 | config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT | |
993 | bool | |
994 | depends on MMU | |
e7142bf5 | 995 | select ARCH_HAS_ELF_RANDOMIZE |
67f3977f | 996 | |
b9ab5ebb JP |
997 | config HAVE_STACK_VALIDATION |
998 | bool | |
999 | help | |
1000 | Architecture supports the 'objtool check' host tool command, which | |
1001 | performs compile-time stack metadata validation. | |
1002 | ||
af085d90 JP |
1003 | config HAVE_RELIABLE_STACKTRACE |
1004 | bool | |
1005 | help | |
140d7e88 MB |
1006 | Architecture has either save_stack_trace_tsk_reliable() or |
1007 | arch_stack_walk_reliable() function which only returns a stack trace | |
1008 | if it can guarantee the trace is reliable. | |
af085d90 | 1009 | |
468a9428 GS |
1010 | config HAVE_ARCH_HASH |
1011 | bool | |
1012 | default n | |
1013 | help | |
1014 | If this is set, the architecture provides an <asm/hash.h> | |
1015 | file which provides platform-specific implementations of some | |
1016 | functions in <linux/hash.h> or fs/namei.c. | |
1017 | ||
666047fe FT |
1018 | config HAVE_ARCH_NVRAM_OPS |
1019 | bool | |
1020 | ||
3a495511 WBG |
1021 | config ISA_BUS_API |
1022 | def_bool ISA | |
1023 | ||
d2125043 AV |
1024 | # |
1025 | # ABI hall of shame | |
1026 | # | |
1027 | config CLONE_BACKWARDS | |
1028 | bool | |
1029 | help | |
1030 | Architecture has tls passed as the 4th argument of clone(2), | |
1031 | not the 5th one. | |
1032 | ||
1033 | config CLONE_BACKWARDS2 | |
1034 | bool | |
1035 | help | |
1036 | Architecture has the first two arguments of clone(2) swapped. | |
1037 | ||
dfa9771a MS |
1038 | config CLONE_BACKWARDS3 |
1039 | bool | |
1040 | help | |
1041 | Architecture has tls passed as the 3rd argument of clone(2), | |
1042 | not the 5th one. | |
1043 | ||
eaca6eae AV |
1044 | config ODD_RT_SIGACTION |
1045 | bool | |
1046 | help | |
1047 | Architecture has unusual rt_sigaction(2) arguments | |
1048 | ||
0a0e8cdf AV |
1049 | config OLD_SIGSUSPEND |
1050 | bool | |
1051 | help | |
1052 | Architecture has old sigsuspend(2) syscall, of one-argument variety | |
1053 | ||
1054 | config OLD_SIGSUSPEND3 | |
1055 | bool | |
1056 | help | |
1057 | Even weirder antique ABI - three-argument sigsuspend(2) | |
1058 | ||
495dfbf7 AV |
1059 | config OLD_SIGACTION |
1060 | bool | |
1061 | help | |
1062 | Architecture has old sigaction(2) syscall. Nope, not the same | |
1063 | as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), | |
1064 | but fairly different variant of sigaction(2), thanks to OSF/1 | |
1065 | compatibility... | |
1066 | ||
1067 | config COMPAT_OLD_SIGACTION | |
1068 | bool | |
1069 | ||
17435e5f | 1070 | config COMPAT_32BIT_TIME |
942437c9 AB |
1071 | bool "Provide system calls for 32-bit time_t" |
1072 | default !64BIT || COMPAT | |
17435e5f DD |
1073 | help |
1074 | This enables 32 bit time_t support in addition to 64 bit time_t support. | |
1075 | This is relevant on all 32-bit architectures, and 64-bit architectures | |
1076 | as part of compat syscall handling. | |
1077 | ||
87a4c375 CH |
1078 | config ARCH_NO_PREEMPT |
1079 | bool | |
1080 | ||
cb2c7d1a MS |
1081 | config ARCH_EPHEMERAL_INODES |
1082 | def_bool n | |
1083 | help | |
1084 | An arch should select this symbol if it doesn't keep track of inode | |
1085 | instances on its own, but instead relies on something else (e.g. the | |
1086 | host kernel for an UML kernel). | |
1087 | ||
a50a3f4b TG |
1088 | config ARCH_SUPPORTS_RT |
1089 | bool | |
1090 | ||
fff7fb0b ZZ |
1091 | config CPU_NO_EFFICIENT_FFS |
1092 | def_bool n | |
1093 | ||
ba14a194 AL |
1094 | config HAVE_ARCH_VMAP_STACK |
1095 | def_bool n | |
1096 | help | |
1097 | An arch should select this symbol if it can support kernel stacks | |
1098 | in vmalloc space. This means: | |
1099 | ||
1100 | - vmalloc space must be large enough to hold many kernel stacks. | |
1101 | This may rule out many 32-bit architectures. | |
1102 | ||
1103 | - Stacks in vmalloc space need to work reliably. For example, if | |
1104 | vmap page tables are created on demand, either this mechanism | |
1105 | needs to work while the stack points to a virtual address with | |
1106 | unpopulated page tables or arch code (switch_to() and switch_mm(), | |
1107 | most likely) needs to ensure that the stack's page table entries | |
1108 | are populated before running on a possibly unpopulated stack. | |
1109 | ||
1110 | - If the stack overflows into a guard page, something reasonable | |
1111 | should happen. The definition of "reasonable" is flexible, but | |
1112 | instantly rebooting without logging anything would be unfriendly. | |
1113 | ||
1114 | config VMAP_STACK | |
1115 | default y | |
1116 | bool "Use a virtually-mapped stack" | |
eafb149e | 1117 | depends on HAVE_ARCH_VMAP_STACK |
38dd767d | 1118 | depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC |
a7f7f624 | 1119 | help |
ba14a194 AL |
1120 | Enable this if you want the use virtually-mapped kernel stacks |
1121 | with guard pages. This causes kernel stack overflows to be | |
1122 | caught immediately rather than causing difficult-to-diagnose | |
1123 | corruption. | |
1124 | ||
38dd767d AK |
1125 | To use this with software KASAN modes, the architecture must support |
1126 | backing virtual mappings with real shadow memory, and KASAN_VMALLOC | |
1127 | must be enabled. | |
ba14a194 | 1128 | |
39218ff4 KC |
1129 | config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET |
1130 | def_bool n | |
1131 | help | |
1132 | An arch should select this symbol if it can support kernel stack | |
1133 | offset randomization with calls to add_random_kstack_offset() | |
1134 | during syscall entry and choose_random_kstack_offset() during | |
1135 | syscall exit. Careful removal of -fstack-protector-strong and | |
1136 | -fstack-protector should also be applied to the entry code and | |
1137 | closely examined, as the artificial stack bump looks like an array | |
1138 | to the compiler, so it will attempt to add canary checks regardless | |
1139 | of the static branch state. | |
1140 | ||
1141 | config RANDOMIZE_KSTACK_OFFSET_DEFAULT | |
1142 | bool "Randomize kernel stack offset on syscall entry" | |
1143 | depends on HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET | |
7ce41f09 | 1144 | depends on INIT_STACK_NONE || !CC_IS_CLANG || CLANG_VERSION >= 140000 |
39218ff4 KC |
1145 | help |
1146 | The kernel stack offset can be randomized (after pt_regs) by | |
1147 | roughly 5 bits of entropy, frustrating memory corruption | |
1148 | attacks that depend on stack address determinism or | |
1149 | cross-syscall address exposures. This feature is controlled | |
1150 | by kernel boot param "randomize_kstack_offset=on/off", and this | |
1151 | config chooses the default boot state. | |
1152 | ||
ad21fc4f LA |
1153 | config ARCH_OPTIONAL_KERNEL_RWX |
1154 | def_bool n | |
1155 | ||
1156 | config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
1157 | def_bool n | |
1158 | ||
1159 | config ARCH_HAS_STRICT_KERNEL_RWX | |
1160 | def_bool n | |
1161 | ||
0f5bf6d0 | 1162 | config STRICT_KERNEL_RWX |
ad21fc4f LA |
1163 | bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX |
1164 | depends on ARCH_HAS_STRICT_KERNEL_RWX | |
1165 | default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
1166 | help | |
1167 | If this is set, kernel text and rodata memory will be made read-only, | |
1168 | and non-text memory will be made non-executable. This provides | |
1169 | protection against certain security exploits (e.g. executing the heap | |
1170 | or modifying text) | |
1171 | ||
1172 | These features are considered standard security practice these days. | |
1173 | You should say Y here in almost all cases. | |
1174 | ||
1175 | config ARCH_HAS_STRICT_MODULE_RWX | |
1176 | def_bool n | |
1177 | ||
0f5bf6d0 | 1178 | config STRICT_MODULE_RWX |
ad21fc4f LA |
1179 | bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX |
1180 | depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES | |
1181 | default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
1182 | help | |
1183 | If this is set, module text and rodata memory will be made read-only, | |
1184 | and non-text memory will be made non-executable. This provides | |
1185 | protection against certain security exploits (e.g. writing to text) | |
1186 | ||
ea8c64ac CH |
1187 | # select if the architecture provides an asm/dma-direct.h header |
1188 | config ARCH_HAS_PHYS_TO_DMA | |
1189 | bool | |
1190 | ||
04f264d3 PB |
1191 | config HAVE_ARCH_COMPILER_H |
1192 | bool | |
1193 | help | |
1194 | An architecture can select this if it provides an | |
1195 | asm/compiler.h header that should be included after | |
1196 | linux/compiler-*.h in order to override macro definitions that those | |
1197 | headers generally provide. | |
1198 | ||
271ca788 AB |
1199 | config HAVE_ARCH_PREL32_RELOCATIONS |
1200 | bool | |
1201 | help | |
1202 | May be selected by an architecture if it supports place-relative | |
1203 | 32-bit relocations, both in the toolchain and in the module loader, | |
1204 | in which case relative references can be used in special sections | |
1205 | for PCI fixup, initcalls etc which are only half the size on 64 bit | |
1206 | architectures, and don't require runtime relocation on relocatable | |
1207 | kernels. | |
1208 | ||
ce9084ba AB |
1209 | config ARCH_USE_MEMREMAP_PROT |
1210 | bool | |
1211 | ||
fb346fd9 WL |
1212 | config LOCK_EVENT_COUNTS |
1213 | bool "Locking event counts collection" | |
1214 | depends on DEBUG_FS | |
a7f7f624 | 1215 | help |
fb346fd9 WL |
1216 | Enable light-weight counting of various locking related events |
1217 | in the system with minimal performance impact. This reduces | |
1218 | the chance of application behavior change because of timing | |
1219 | differences. The counts are reported via debugfs. | |
1220 | ||
5cf896fb PC |
1221 | # Select if the architecture has support for applying RELR relocations. |
1222 | config ARCH_HAS_RELR | |
1223 | bool | |
1224 | ||
1225 | config RELR | |
1226 | bool "Use RELR relocation packing" | |
1227 | depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR | |
1228 | default y | |
1229 | help | |
1230 | Store the kernel's dynamic relocations in the RELR relocation packing | |
1231 | format. Requires a compatible linker (LLD supports this feature), as | |
1232 | well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy | |
1233 | are compatible). | |
1234 | ||
0c9c1d56 TJB |
1235 | config ARCH_HAS_MEM_ENCRYPT |
1236 | bool | |
1237 | ||
a650b468 TL |
1238 | config ARCH_HAS_CC_PLATFORM |
1239 | bool | |
1240 | ||
0e242208 HN |
1241 | config HAVE_SPARSE_SYSCALL_NR |
1242 | bool | |
1243 | help | |
1244 | An architecture should select this if its syscall numbering is sparse | |
1245 | to save space. For example, MIPS architecture has a syscall array with | |
1246 | entries at 4000, 5000 and 6000 locations. This option turns on syscall | |
1247 | related optimizations for a given architecture. | |
1248 | ||
d60d7de3 SS |
1249 | config ARCH_HAS_VDSO_DATA |
1250 | bool | |
1251 | ||
115284d8 JP |
1252 | config HAVE_STATIC_CALL |
1253 | bool | |
1254 | ||
9183c3f9 JP |
1255 | config HAVE_STATIC_CALL_INLINE |
1256 | bool | |
1257 | depends on HAVE_STATIC_CALL | |
1258 | ||
6ef869e0 MH |
1259 | config HAVE_PREEMPT_DYNAMIC |
1260 | bool | |
1261 | depends on HAVE_STATIC_CALL | |
1262 | depends on GENERIC_ENTRY | |
1263 | help | |
1264 | Select this if the architecture support boot time preempt setting | |
1265 | on top of static calls. It is strongly advised to support inline | |
1266 | static call to avoid any overhead. | |
1267 | ||
59612b24 NC |
1268 | config ARCH_WANT_LD_ORPHAN_WARN |
1269 | bool | |
1270 | help | |
1271 | An arch should select this symbol once all linker sections are explicitly | |
1272 | included, size-asserted, or discarded in the linker scripts. This is | |
1273 | important because we never want expected sections to be placed heuristically | |
1274 | by the linker, since the locations of such sections can change between linker | |
1275 | versions. | |
1276 | ||
4f5b0c17 MR |
1277 | config HAVE_ARCH_PFN_VALID |
1278 | bool | |
1279 | ||
5d6ad668 MR |
1280 | config ARCH_SUPPORTS_DEBUG_PAGEALLOC |
1281 | bool | |
1282 | ||
2ca408d9 BG |
1283 | config ARCH_SPLIT_ARG64 |
1284 | bool | |
1285 | help | |
1286 | If a 32-bit architecture requires 64-bit arguments to be split into | |
1287 | pairs of 32-bit arguments, select this option. | |
1288 | ||
7facdc42 AV |
1289 | config ARCH_HAS_ELFCORE_COMPAT |
1290 | bool | |
1291 | ||
58e106e7 BS |
1292 | config ARCH_HAS_PARANOID_L1D_FLUSH |
1293 | bool | |
1294 | ||
2256cacf TG |
1295 | config DYNAMIC_SIGFRAME |
1296 | bool | |
1297 | ||
2521f2c2 | 1298 | source "kernel/gcov/Kconfig" |
45332b1b MY |
1299 | |
1300 | source "scripts/gcc-plugins/Kconfig" | |
fa1b5d09 | 1301 | |
22471e13 | 1302 | endmenu |