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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 | ||
da32b581 CM |
27 | config ARCH_HAS_SUBPAGE_FAULTS |
28 | bool | |
29 | help | |
30 | Select if the architecture can check permissions at sub-page | |
31 | granularity (e.g. arm64 MTE). The probe_user_*() functions | |
32 | must be implemented. | |
33 | ||
05736e4a TG |
34 | config HOTPLUG_SMT |
35 | bool | |
36 | ||
142781e1 TG |
37 | config GENERIC_ENTRY |
38 | bool | |
39 | ||
125e5645 MD |
40 | config KPROBES |
41 | bool "Kprobes" | |
05ed160e | 42 | depends on MODULES |
125e5645 | 43 | depends on HAVE_KPROBES |
05ed160e | 44 | select KALLSYMS |
835f14ed | 45 | select TASKS_RCU if PREEMPTION |
125e5645 MD |
46 | help |
47 | Kprobes allows you to trap at almost any kernel address and | |
48 | execute a callback function. register_kprobe() establishes | |
49 | a probepoint and specifies the callback. Kprobes is useful | |
50 | for kernel debugging, non-intrusive instrumentation and testing. | |
51 | If in doubt, say "N". | |
52 | ||
45f81b1c | 53 | config JUMP_LABEL |
24b54fee KK |
54 | bool "Optimize very unlikely/likely branches" |
55 | depends on HAVE_ARCH_JUMP_LABEL | |
4ab7674f | 56 | select OBJTOOL if HAVE_JUMP_LABEL_HACK |
24b54fee KK |
57 | help |
58 | This option enables a transparent branch optimization that | |
c5905afb IM |
59 | makes certain almost-always-true or almost-always-false branch |
60 | conditions even cheaper to execute within the kernel. | |
61 | ||
62 | Certain performance-sensitive kernel code, such as trace points, | |
63 | scheduler functionality, networking code and KVM have such | |
64 | branches and include support for this optimization technique. | |
65 | ||
24b54fee | 66 | If it is detected that the compiler has support for "asm goto", |
c5905afb IM |
67 | the kernel will compile such branches with just a nop |
68 | instruction. When the condition flag is toggled to true, the | |
69 | nop will be converted to a jump instruction to execute the | |
70 | conditional block of instructions. | |
71 | ||
72 | This technique lowers overhead and stress on the branch prediction | |
73 | of the processor and generally makes the kernel faster. The update | |
74 | of the condition is slower, but those are always very rare. | |
45f81b1c | 75 | |
c5905afb IM |
76 | ( On 32-bit x86, the necessary options added to the compiler |
77 | flags may increase the size of the kernel slightly. ) | |
45f81b1c | 78 | |
1987c947 PZ |
79 | config STATIC_KEYS_SELFTEST |
80 | bool "Static key selftest" | |
81 | depends on JUMP_LABEL | |
82 | help | |
83 | Boot time self-test of the branch patching code. | |
84 | ||
f03c4129 PZ |
85 | config STATIC_CALL_SELFTEST |
86 | bool "Static call selftest" | |
87 | depends on HAVE_STATIC_CALL | |
88 | help | |
89 | Boot time self-test of the call patching code. | |
90 | ||
afd66255 | 91 | config OPTPROBES |
5cc718b9 MH |
92 | def_bool y |
93 | depends on KPROBES && HAVE_OPTPROBES | |
01b1d88b | 94 | select TASKS_RCU if PREEMPTION |
afd66255 | 95 | |
e7dbfe34 MH |
96 | config KPROBES_ON_FTRACE |
97 | def_bool y | |
98 | depends on KPROBES && HAVE_KPROBES_ON_FTRACE | |
99 | depends on DYNAMIC_FTRACE_WITH_REGS | |
100 | help | |
101 | If function tracer is enabled and the arch supports full | |
102 | passing of pt_regs to function tracing, then kprobes can | |
103 | optimize on top of function tracing. | |
104 | ||
2b144498 | 105 | config UPROBES |
09294e31 | 106 | def_bool n |
e8f4aa60 | 107 | depends on ARCH_SUPPORTS_UPROBES |
2b144498 | 108 | help |
7b2d81d4 IM |
109 | Uprobes is the user-space counterpart to kprobes: they |
110 | enable instrumentation applications (such as 'perf probe') | |
111 | to establish unintrusive probes in user-space binaries and | |
112 | libraries, by executing handler functions when the probes | |
113 | are hit by user-space applications. | |
114 | ||
115 | ( These probes come in the form of single-byte breakpoints, | |
116 | managed by the kernel and kept transparent to the probed | |
117 | application. ) | |
2b144498 | 118 | |
adab66b7 SRV |
119 | config HAVE_64BIT_ALIGNED_ACCESS |
120 | def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS | |
121 | help | |
122 | Some architectures require 64 bit accesses to be 64 bit | |
123 | aligned, which also requires structs containing 64 bit values | |
124 | to be 64 bit aligned too. This includes some 32 bit | |
125 | architectures which can do 64 bit accesses, as well as 64 bit | |
126 | architectures without unaligned access. | |
127 | ||
128 | This symbol should be selected by an architecture if 64 bit | |
129 | accesses are required to be 64 bit aligned in this way even | |
130 | though it is not a 64 bit architecture. | |
131 | ||
ba1a297d LB |
132 | See Documentation/core-api/unaligned-memory-access.rst for |
133 | more information on the topic of unaligned memory accesses. | |
adab66b7 | 134 | |
58340a07 | 135 | config HAVE_EFFICIENT_UNALIGNED_ACCESS |
9ba16087 | 136 | bool |
58340a07 JB |
137 | help |
138 | Some architectures are unable to perform unaligned accesses | |
139 | without the use of get_unaligned/put_unaligned. Others are | |
140 | unable to perform such accesses efficiently (e.g. trap on | |
141 | unaligned access and require fixing it up in the exception | |
142 | handler.) | |
143 | ||
144 | This symbol should be selected by an architecture if it can | |
145 | perform unaligned accesses efficiently to allow different | |
146 | code paths to be selected for these cases. Some network | |
147 | drivers, for example, could opt to not fix up alignment | |
148 | problems with received packets if doing so would not help | |
149 | much. | |
150 | ||
c9b54d6f | 151 | See Documentation/core-api/unaligned-memory-access.rst for more |
58340a07 JB |
152 | information on the topic of unaligned memory accesses. |
153 | ||
cf66bb93 | 154 | config ARCH_USE_BUILTIN_BSWAP |
24b54fee KK |
155 | bool |
156 | help | |
cf66bb93 DW |
157 | Modern versions of GCC (since 4.4) have builtin functions |
158 | for handling byte-swapping. Using these, instead of the old | |
159 | inline assembler that the architecture code provides in the | |
160 | __arch_bswapXX() macros, allows the compiler to see what's | |
161 | happening and offers more opportunity for optimisation. In | |
162 | particular, the compiler will be able to combine the byteswap | |
163 | with a nearby load or store and use load-and-swap or | |
164 | store-and-swap instructions if the architecture has them. It | |
165 | should almost *never* result in code which is worse than the | |
166 | hand-coded assembler in <asm/swab.h>. But just in case it | |
167 | does, the use of the builtins is optional. | |
168 | ||
169 | Any architecture with load-and-swap or store-and-swap | |
170 | instructions should set this. And it shouldn't hurt to set it | |
171 | on architectures that don't have such instructions. | |
172 | ||
9edddaa2 AM |
173 | config KRETPROBES |
174 | def_bool y | |
73f9b911 MH |
175 | depends on KPROBES && (HAVE_KRETPROBES || HAVE_RETHOOK) |
176 | ||
177 | config KRETPROBE_ON_RETHOOK | |
178 | def_bool y | |
179 | depends on HAVE_RETHOOK | |
180 | depends on KRETPROBES | |
181 | select RETHOOK | |
9edddaa2 | 182 | |
7c68af6e AK |
183 | config USER_RETURN_NOTIFIER |
184 | bool | |
185 | depends on HAVE_USER_RETURN_NOTIFIER | |
186 | help | |
187 | Provide a kernel-internal notification when a cpu is about to | |
188 | switch to user mode. | |
189 | ||
28b2ee20 | 190 | config HAVE_IOREMAP_PROT |
9ba16087 | 191 | bool |
28b2ee20 | 192 | |
125e5645 | 193 | config HAVE_KPROBES |
9ba16087 | 194 | bool |
9edddaa2 AM |
195 | |
196 | config HAVE_KRETPROBES | |
9ba16087 | 197 | bool |
74bc7cee | 198 | |
afd66255 MH |
199 | config HAVE_OPTPROBES |
200 | bool | |
d314d74c | 201 | |
e7dbfe34 MH |
202 | config HAVE_KPROBES_ON_FTRACE |
203 | bool | |
204 | ||
1f6d3a8f MH |
205 | config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE |
206 | bool | |
207 | help | |
208 | Since kretprobes modifies return address on the stack, the | |
209 | stacktrace may see the kretprobe trampoline address instead | |
210 | of correct one. If the architecture stacktrace code and | |
211 | unwinder can adjust such entries, select this configuration. | |
212 | ||
540adea3 | 213 | config HAVE_FUNCTION_ERROR_INJECTION |
9802d865 JB |
214 | bool |
215 | ||
42a0bb3f PM |
216 | config HAVE_NMI |
217 | bool | |
218 | ||
a257cacc CL |
219 | config HAVE_FUNCTION_DESCRIPTORS |
220 | bool | |
221 | ||
4aae683f MY |
222 | config TRACE_IRQFLAGS_SUPPORT |
223 | bool | |
224 | ||
4510bffb MR |
225 | config TRACE_IRQFLAGS_NMI_SUPPORT |
226 | bool | |
227 | ||
1f5a4ad9 RM |
228 | # |
229 | # An arch should select this if it provides all these things: | |
230 | # | |
231 | # task_pt_regs() in asm/processor.h or asm/ptrace.h | |
232 | # arch_has_single_step() if there is hardware single-step support | |
233 | # arch_has_block_step() if there is hardware block-step support | |
1f5a4ad9 RM |
234 | # asm/syscall.h supplying asm-generic/syscall.h interface |
235 | # linux/regset.h user_regset interfaces | |
236 | # CORE_DUMP_USE_REGSET #define'd in linux/elf.h | |
153474ba | 237 | # TIF_SYSCALL_TRACE calls ptrace_report_syscall_{entry,exit} |
03248add | 238 | # TIF_NOTIFY_RESUME calls resume_user_mode_work() |
1f5a4ad9 RM |
239 | # |
240 | config HAVE_ARCH_TRACEHOOK | |
9ba16087 | 241 | bool |
1f5a4ad9 | 242 | |
c64be2bb MS |
243 | config HAVE_DMA_CONTIGUOUS |
244 | bool | |
245 | ||
29d5e047 | 246 | config GENERIC_SMP_IDLE_THREAD |
24b54fee | 247 | bool |
29d5e047 | 248 | |
485cf5da | 249 | config GENERIC_IDLE_POLL_SETUP |
24b54fee | 250 | bool |
485cf5da | 251 | |
6974f0c4 DM |
252 | config ARCH_HAS_FORTIFY_SOURCE |
253 | bool | |
254 | help | |
255 | An architecture should select this when it can successfully | |
256 | build and run with CONFIG_FORTIFY_SOURCE. | |
257 | ||
d8ae8a37 CH |
258 | # |
259 | # Select if the arch provides a historic keepinit alias for the retain_initrd | |
260 | # command line option | |
261 | # | |
262 | config ARCH_HAS_KEEPINITRD | |
263 | bool | |
264 | ||
d2852a22 DB |
265 | # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h |
266 | config ARCH_HAS_SET_MEMORY | |
267 | bool | |
268 | ||
d253ca0c RE |
269 | # Select if arch has all set_direct_map_invalid/default() functions |
270 | config ARCH_HAS_SET_DIRECT_MAP | |
271 | bool | |
272 | ||
c30700db | 273 | # |
fa7e2247 | 274 | # Select if the architecture provides the arch_dma_set_uncached symbol to |
a86ecfa6 | 275 | # either provide an uncached segment alias for a DMA allocation, or |
fa7e2247 | 276 | # to remap the page tables in place. |
c30700db | 277 | # |
fa7e2247 | 278 | config ARCH_HAS_DMA_SET_UNCACHED |
c30700db CH |
279 | bool |
280 | ||
999a5d12 CH |
281 | # |
282 | # Select if the architectures provides the arch_dma_clear_uncached symbol | |
283 | # to undo an in-place page table remap for uncached access. | |
284 | # | |
285 | config ARCH_HAS_DMA_CLEAR_UNCACHED | |
c30700db CH |
286 | bool |
287 | ||
0500871f DH |
288 | # Select if arch init_task must go in the __init_task_data section |
289 | config ARCH_TASK_STRUCT_ON_STACK | |
24b54fee | 290 | bool |
a4a2eb49 | 291 | |
f5e10287 TG |
292 | # Select if arch has its private alloc_task_struct() function |
293 | config ARCH_TASK_STRUCT_ALLOCATOR | |
294 | bool | |
295 | ||
5905429a KC |
296 | config HAVE_ARCH_THREAD_STRUCT_WHITELIST |
297 | bool | |
298 | depends on !ARCH_TASK_STRUCT_ALLOCATOR | |
299 | help | |
300 | An architecture should select this to provide hardened usercopy | |
301 | knowledge about what region of the thread_struct should be | |
302 | whitelisted for copying to userspace. Normally this is only the | |
303 | FPU registers. Specifically, arch_thread_struct_whitelist() | |
304 | should be implemented. Without this, the entire thread_struct | |
305 | field in task_struct will be left whitelisted. | |
306 | ||
b235beea LT |
307 | # Select if arch has its private alloc_thread_stack() function |
308 | config ARCH_THREAD_STACK_ALLOCATOR | |
f5e10287 TG |
309 | bool |
310 | ||
5aaeb5c0 IM |
311 | # Select if arch wants to size task_struct dynamically via arch_task_struct_size: |
312 | config ARCH_WANTS_DYNAMIC_TASK_STRUCT | |
313 | bool | |
314 | ||
51c2ee6d ND |
315 | config ARCH_WANTS_NO_INSTR |
316 | bool | |
317 | help | |
318 | An architecture should select this if the noinstr macro is being used on | |
319 | functions to denote that the toolchain should avoid instrumenting such | |
320 | functions and is required for correctness. | |
321 | ||
942fa985 YN |
322 | config ARCH_32BIT_OFF_T |
323 | bool | |
324 | depends on !64BIT | |
325 | help | |
326 | All new 32-bit architectures should have 64-bit off_t type on | |
327 | userspace side which corresponds to the loff_t kernel type. This | |
328 | is the requirement for modern ABIs. Some existing architectures | |
329 | still support 32-bit off_t. This option is enabled for all such | |
330 | architectures explicitly. | |
331 | ||
96c0a6a7 HC |
332 | # Selected by 64 bit architectures which have a 32 bit f_tinode in struct ustat |
333 | config ARCH_32BIT_USTAT_F_TINODE | |
334 | bool | |
335 | ||
2ff2b7ec MY |
336 | config HAVE_ASM_MODVERSIONS |
337 | bool | |
338 | help | |
a86ecfa6 | 339 | This symbol should be selected by an architecture if it provides |
2ff2b7ec MY |
340 | <asm/asm-prototypes.h> to support the module versioning for symbols |
341 | exported from assembly code. | |
342 | ||
f850c30c HC |
343 | config HAVE_REGS_AND_STACK_ACCESS_API |
344 | bool | |
e01292b1 | 345 | help |
a86ecfa6 | 346 | This symbol should be selected by an architecture if it supports |
e01292b1 HC |
347 | the API needed to access registers and stack entries from pt_regs, |
348 | declared in asm/ptrace.h | |
349 | For example the kprobes-based event tracer needs this API. | |
f850c30c | 350 | |
d7822b1e MD |
351 | config HAVE_RSEQ |
352 | bool | |
353 | depends on HAVE_REGS_AND_STACK_ACCESS_API | |
354 | help | |
355 | This symbol should be selected by an architecture if it | |
356 | supports an implementation of restartable sequences. | |
357 | ||
3c88ee19 MH |
358 | config HAVE_FUNCTION_ARG_ACCESS_API |
359 | bool | |
360 | help | |
a86ecfa6 | 361 | This symbol should be selected by an architecture if it supports |
3c88ee19 MH |
362 | the API needed to access function arguments from pt_regs, |
363 | declared in asm/ptrace.h | |
364 | ||
62a038d3 P |
365 | config HAVE_HW_BREAKPOINT |
366 | bool | |
99e8c5a3 | 367 | depends on PERF_EVENTS |
62a038d3 | 368 | |
0102752e FW |
369 | config HAVE_MIXED_BREAKPOINTS_REGS |
370 | bool | |
371 | depends on HAVE_HW_BREAKPOINT | |
372 | help | |
373 | Depending on the arch implementation of hardware breakpoints, | |
374 | some of them have separate registers for data and instruction | |
375 | breakpoints addresses, others have mixed registers to store | |
376 | them but define the access type in a control register. | |
377 | Select this option if your arch implements breakpoints under the | |
378 | latter fashion. | |
379 | ||
7c68af6e AK |
380 | config HAVE_USER_RETURN_NOTIFIER |
381 | bool | |
a1922ed6 | 382 | |
c01d4323 FW |
383 | config HAVE_PERF_EVENTS_NMI |
384 | bool | |
23637d47 FW |
385 | help |
386 | System hardware can generate an NMI using the perf event | |
387 | subsystem. Also has support for calculating CPU cycle events | |
388 | to determine how many clock cycles in a given period. | |
c01d4323 | 389 | |
05a4a952 NP |
390 | config HAVE_HARDLOCKUP_DETECTOR_PERF |
391 | bool | |
392 | depends on HAVE_PERF_EVENTS_NMI | |
393 | help | |
394 | The arch chooses to use the generic perf-NMI-based hardlockup | |
395 | detector. Must define HAVE_PERF_EVENTS_NMI. | |
396 | ||
397 | config HAVE_NMI_WATCHDOG | |
398 | depends on HAVE_NMI | |
399 | bool | |
400 | help | |
401 | The arch provides a low level NMI watchdog. It provides | |
402 | asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). | |
403 | ||
404 | config HAVE_HARDLOCKUP_DETECTOR_ARCH | |
405 | bool | |
406 | select HAVE_NMI_WATCHDOG | |
407 | help | |
408 | The arch chooses to provide its own hardlockup detector, which is | |
409 | a superset of the HAVE_NMI_WATCHDOG. It also conforms to config | |
410 | interfaces and parameters provided by hardlockup detector subsystem. | |
411 | ||
c5e63197 JO |
412 | config HAVE_PERF_REGS |
413 | bool | |
414 | help | |
415 | Support selective register dumps for perf events. This includes | |
416 | bit-mapping of each registers and a unique architecture id. | |
417 | ||
c5ebcedb JO |
418 | config HAVE_PERF_USER_STACK_DUMP |
419 | bool | |
420 | help | |
421 | Support user stack dumps for perf event samples. This needs | |
422 | access to the user stack pointer which is not unified across | |
423 | architectures. | |
424 | ||
bf5438fc JB |
425 | config HAVE_ARCH_JUMP_LABEL |
426 | bool | |
427 | ||
50ff18ab AB |
428 | config HAVE_ARCH_JUMP_LABEL_RELATIVE |
429 | bool | |
430 | ||
0d6e24d4 PZ |
431 | config MMU_GATHER_TABLE_FREE |
432 | bool | |
433 | ||
ff2e6d72 | 434 | config MMU_GATHER_RCU_TABLE_FREE |
26723911 | 435 | bool |
0d6e24d4 | 436 | select MMU_GATHER_TABLE_FREE |
26723911 | 437 | |
3af4bd03 | 438 | config MMU_GATHER_PAGE_SIZE |
ed6a7935 PZ |
439 | bool |
440 | ||
27796d03 PZ |
441 | config MMU_GATHER_NO_RANGE |
442 | bool | |
1e9fdf21 PZ |
443 | select MMU_GATHER_MERGE_VMAS |
444 | ||
445 | config MMU_GATHER_NO_FLUSH_CACHE | |
446 | bool | |
447 | ||
448 | config MMU_GATHER_MERGE_VMAS | |
449 | bool | |
27796d03 | 450 | |
580a586c | 451 | config MMU_GATHER_NO_GATHER |
952a31c9 | 452 | bool |
0d6e24d4 | 453 | depends on MMU_GATHER_TABLE_FREE |
952a31c9 | 454 | |
d53c3dfb NP |
455 | config ARCH_WANT_IRQS_OFF_ACTIVATE_MM |
456 | bool | |
457 | help | |
458 | Temporary select until all architectures can be converted to have | |
459 | irqs disabled over activate_mm. Architectures that do IPI based TLB | |
460 | shootdowns should enable this. | |
461 | ||
df013ffb HY |
462 | config ARCH_HAVE_NMI_SAFE_CMPXCHG |
463 | bool | |
464 | ||
43570fd2 HC |
465 | config HAVE_ALIGNED_STRUCT_PAGE |
466 | bool | |
467 | help | |
468 | This makes sure that struct pages are double word aligned and that | |
469 | e.g. the SLUB allocator can perform double word atomic operations | |
470 | on a struct page for better performance. However selecting this | |
471 | might increase the size of a struct page by a word. | |
472 | ||
4156153c HC |
473 | config HAVE_CMPXCHG_LOCAL |
474 | bool | |
475 | ||
2565409f HC |
476 | config HAVE_CMPXCHG_DOUBLE |
477 | bool | |
478 | ||
77e58496 PM |
479 | config ARCH_WEAK_RELEASE_ACQUIRE |
480 | bool | |
481 | ||
c1d7e01d WD |
482 | config ARCH_WANT_IPC_PARSE_VERSION |
483 | bool | |
484 | ||
485 | config ARCH_WANT_COMPAT_IPC_PARSE_VERSION | |
486 | bool | |
487 | ||
48b25c43 | 488 | config ARCH_WANT_OLD_COMPAT_IPC |
c1d7e01d | 489 | select ARCH_WANT_COMPAT_IPC_PARSE_VERSION |
48b25c43 CM |
490 | bool |
491 | ||
282a181b YZ |
492 | config HAVE_ARCH_SECCOMP |
493 | bool | |
494 | help | |
495 | An arch should select this symbol to support seccomp mode 1 (the fixed | |
496 | syscall policy), and must provide an overrides for __NR_seccomp_sigreturn, | |
497 | and compat syscalls if the asm-generic/seccomp.h defaults need adjustment: | |
498 | - __NR_seccomp_read_32 | |
499 | - __NR_seccomp_write_32 | |
500 | - __NR_seccomp_exit_32 | |
501 | - __NR_seccomp_sigreturn_32 | |
502 | ||
e2cfabdf WD |
503 | config HAVE_ARCH_SECCOMP_FILTER |
504 | bool | |
282a181b | 505 | select HAVE_ARCH_SECCOMP |
e2cfabdf | 506 | help |
fb0fadf9 | 507 | An arch should select this symbol if it provides all of these things: |
282a181b | 508 | - all the requirements for HAVE_ARCH_SECCOMP |
bb6ea430 WD |
509 | - syscall_get_arch() |
510 | - syscall_get_arguments() | |
511 | - syscall_rollback() | |
512 | - syscall_set_return_value() | |
fb0fadf9 WD |
513 | - SIGSYS siginfo_t support |
514 | - secure_computing is called from a ptrace_event()-safe context | |
515 | - secure_computing return value is checked and a return value of -1 | |
516 | results in the system call being skipped immediately. | |
48dc92b9 | 517 | - seccomp syscall wired up |
0d8315dd YZ |
518 | - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE, |
519 | SECCOMP_ARCH_NATIVE_NR, SECCOMP_ARCH_NATIVE_NAME defined. If | |
520 | COMPAT is supported, have the SECCOMP_ARCH_COMPAT* defines too. | |
e2cfabdf | 521 | |
282a181b YZ |
522 | config SECCOMP |
523 | prompt "Enable seccomp to safely execute untrusted bytecode" | |
524 | def_bool y | |
525 | depends on HAVE_ARCH_SECCOMP | |
526 | help | |
527 | This kernel feature is useful for number crunching applications | |
528 | that may need to handle untrusted bytecode during their | |
529 | execution. By using pipes or other transports made available | |
530 | to the process as file descriptors supporting the read/write | |
531 | syscalls, it's possible to isolate those applications in their | |
532 | own address space using seccomp. Once seccomp is enabled via | |
533 | prctl(PR_SET_SECCOMP) or the seccomp() syscall, it cannot be | |
534 | disabled and the task is only allowed to execute a few safe | |
535 | syscalls defined by each seccomp mode. | |
536 | ||
537 | If unsure, say Y. | |
538 | ||
e2cfabdf WD |
539 | config SECCOMP_FILTER |
540 | def_bool y | |
541 | depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET | |
542 | help | |
543 | Enable tasks to build secure computing environments defined | |
544 | in terms of Berkeley Packet Filter programs which implement | |
545 | task-defined system call filtering polices. | |
546 | ||
5fb94e9c | 547 | See Documentation/userspace-api/seccomp_filter.rst for details. |
e2cfabdf | 548 | |
0d8315dd YZ |
549 | config SECCOMP_CACHE_DEBUG |
550 | bool "Show seccomp filter cache status in /proc/pid/seccomp_cache" | |
551 | depends on SECCOMP_FILTER && !HAVE_SPARSE_SYSCALL_NR | |
552 | depends on PROC_FS | |
553 | help | |
554 | This enables the /proc/pid/seccomp_cache interface to monitor | |
555 | seccomp cache data. The file format is subject to change. Reading | |
556 | the file requires CAP_SYS_ADMIN. | |
557 | ||
558 | This option is for debugging only. Enabling presents the risk that | |
559 | an adversary may be able to infer the seccomp filter logic. | |
560 | ||
561 | If unsure, say N. | |
562 | ||
afaef01c AP |
563 | config HAVE_ARCH_STACKLEAK |
564 | bool | |
565 | help | |
566 | An architecture should select this if it has the code which | |
567 | fills the used part of the kernel stack with the STACKLEAK_POISON | |
568 | value before returning from system calls. | |
569 | ||
d148eac0 | 570 | config HAVE_STACKPROTECTOR |
19952a92 KC |
571 | bool |
572 | help | |
573 | An arch should select this symbol if: | |
19952a92 KC |
574 | - it has implemented a stack canary (e.g. __stack_chk_guard) |
575 | ||
050e9baa | 576 | config STACKPROTECTOR |
2a61f474 | 577 | bool "Stack Protector buffer overflow detection" |
d148eac0 | 578 | depends on HAVE_STACKPROTECTOR |
2a61f474 MY |
579 | depends on $(cc-option,-fstack-protector) |
580 | default y | |
19952a92 | 581 | help |
8779657d | 582 | This option turns on the "stack-protector" GCC feature. This |
19952a92 KC |
583 | feature puts, at the beginning of functions, a canary value on |
584 | the stack just before the return address, and validates | |
585 | the value just before actually returning. Stack based buffer | |
586 | overflows (that need to overwrite this return address) now also | |
587 | overwrite the canary, which gets detected and the attack is then | |
588 | neutralized via a kernel panic. | |
589 | ||
8779657d KC |
590 | Functions will have the stack-protector canary logic added if they |
591 | have an 8-byte or larger character array on the stack. | |
592 | ||
19952a92 | 593 | This feature requires gcc version 4.2 or above, or a distribution |
8779657d KC |
594 | gcc with the feature backported ("-fstack-protector"). |
595 | ||
596 | On an x86 "defconfig" build, this feature adds canary checks to | |
597 | about 3% of all kernel functions, which increases kernel code size | |
598 | by about 0.3%. | |
599 | ||
050e9baa | 600 | config STACKPROTECTOR_STRONG |
2a61f474 | 601 | bool "Strong Stack Protector" |
050e9baa | 602 | depends on STACKPROTECTOR |
2a61f474 MY |
603 | depends on $(cc-option,-fstack-protector-strong) |
604 | default y | |
8779657d KC |
605 | help |
606 | Functions will have the stack-protector canary logic added in any | |
607 | of the following conditions: | |
608 | ||
609 | - local variable's address used as part of the right hand side of an | |
610 | assignment or function argument | |
611 | - local variable is an array (or union containing an array), | |
612 | regardless of array type or length | |
613 | - uses register local variables | |
614 | ||
615 | This feature requires gcc version 4.9 or above, or a distribution | |
616 | gcc with the feature backported ("-fstack-protector-strong"). | |
617 | ||
618 | On an x86 "defconfig" build, this feature adds canary checks to | |
619 | about 20% of all kernel functions, which increases the kernel code | |
620 | size by about 2%. | |
621 | ||
d08b9f0c ST |
622 | config ARCH_SUPPORTS_SHADOW_CALL_STACK |
623 | bool | |
624 | help | |
afcf5441 DL |
625 | An architecture should select this if it supports the compiler's |
626 | Shadow Call Stack and implements runtime support for shadow stack | |
aa7a65ae | 627 | switching. |
d08b9f0c ST |
628 | |
629 | config SHADOW_CALL_STACK | |
afcf5441 DL |
630 | bool "Shadow Call Stack" |
631 | depends on ARCH_SUPPORTS_SHADOW_CALL_STACK | |
ddc9863e | 632 | depends on DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER |
d08b9f0c | 633 | help |
afcf5441 DL |
634 | This option enables the compiler's Shadow Call Stack, which |
635 | uses a shadow stack to protect function return addresses from | |
636 | being overwritten by an attacker. More information can be found | |
637 | in the compiler's documentation: | |
d08b9f0c | 638 | |
afcf5441 DL |
639 | - Clang: https://clang.llvm.org/docs/ShadowCallStack.html |
640 | - GCC: https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options | |
d08b9f0c ST |
641 | |
642 | Note that security guarantees in the kernel differ from the | |
643 | ones documented for user space. The kernel must store addresses | |
644 | of shadow stacks in memory, which means an attacker capable of | |
645 | reading and writing arbitrary memory may be able to locate them | |
646 | and hijack control flow by modifying the stacks. | |
647 | ||
dc5723b0 ST |
648 | config LTO |
649 | bool | |
650 | help | |
651 | Selected if the kernel will be built using the compiler's LTO feature. | |
652 | ||
653 | config LTO_CLANG | |
654 | bool | |
655 | select LTO | |
656 | help | |
657 | Selected if the kernel will be built using Clang's LTO feature. | |
658 | ||
659 | config ARCH_SUPPORTS_LTO_CLANG | |
660 | bool | |
661 | help | |
662 | An architecture should select this option if it supports: | |
663 | - compiling with Clang, | |
664 | - compiling inline assembly with Clang's integrated assembler, | |
665 | - and linking with LLD. | |
666 | ||
667 | config ARCH_SUPPORTS_LTO_CLANG_THIN | |
668 | bool | |
669 | help | |
670 | An architecture should select this option if it can support Clang's | |
671 | ThinLTO mode. | |
672 | ||
673 | config HAS_LTO_CLANG | |
674 | def_bool y | |
1e68a8af | 675 | depends on CC_IS_CLANG && LD_IS_LLD && AS_IS_LLVM |
dc5723b0 ST |
676 | depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm) |
677 | depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm) | |
678 | depends on ARCH_SUPPORTS_LTO_CLANG | |
679 | depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT | |
bf3c2551 | 680 | depends on !KASAN || KASAN_HW_TAGS |
dc5723b0 | 681 | depends on !GCOV_KERNEL |
dc5723b0 ST |
682 | help |
683 | The compiler and Kconfig options support building with Clang's | |
684 | LTO. | |
685 | ||
686 | choice | |
687 | prompt "Link Time Optimization (LTO)" | |
688 | default LTO_NONE | |
689 | help | |
690 | This option enables Link Time Optimization (LTO), which allows the | |
691 | compiler to optimize binaries globally. | |
692 | ||
693 | If unsure, select LTO_NONE. Note that LTO is very resource-intensive | |
694 | so it's disabled by default. | |
695 | ||
696 | config LTO_NONE | |
697 | bool "None" | |
698 | help | |
699 | Build the kernel normally, without Link Time Optimization (LTO). | |
700 | ||
701 | config LTO_CLANG_FULL | |
702 | bool "Clang Full LTO (EXPERIMENTAL)" | |
703 | depends on HAS_LTO_CLANG | |
704 | depends on !COMPILE_TEST | |
705 | select LTO_CLANG | |
706 | help | |
707 | This option enables Clang's full Link Time Optimization (LTO), which | |
708 | allows the compiler to optimize the kernel globally. If you enable | |
709 | this option, the compiler generates LLVM bitcode instead of ELF | |
710 | object files, and the actual compilation from bitcode happens at | |
711 | the LTO link step, which may take several minutes depending on the | |
712 | kernel configuration. More information can be found from LLVM's | |
713 | documentation: | |
714 | ||
715 | https://llvm.org/docs/LinkTimeOptimization.html | |
716 | ||
717 | During link time, this option can use a large amount of RAM, and | |
718 | may take much longer than the ThinLTO option. | |
719 | ||
720 | config LTO_CLANG_THIN | |
721 | bool "Clang ThinLTO (EXPERIMENTAL)" | |
722 | depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN | |
723 | select LTO_CLANG | |
724 | help | |
725 | This option enables Clang's ThinLTO, which allows for parallel | |
726 | optimization and faster incremental compiles compared to the | |
727 | CONFIG_LTO_CLANG_FULL option. More information can be found | |
728 | from Clang's documentation: | |
729 | ||
730 | https://clang.llvm.org/docs/ThinLTO.html | |
731 | ||
732 | If unsure, say Y. | |
733 | endchoice | |
734 | ||
cf68fffb ST |
735 | config ARCH_SUPPORTS_CFI_CLANG |
736 | bool | |
737 | help | |
738 | An architecture should select this option if it can support Clang's | |
739 | Control-Flow Integrity (CFI) checking. | |
740 | ||
741 | config CFI_CLANG | |
742 | bool "Use Clang's Control Flow Integrity (CFI)" | |
743 | depends on LTO_CLANG && ARCH_SUPPORTS_CFI_CLANG | |
e6f3b3c9 | 744 | depends on CLANG_VERSION >= 140000 |
cf68fffb ST |
745 | select KALLSYMS |
746 | help | |
747 | This option enables Clang’s forward-edge Control Flow Integrity | |
748 | (CFI) checking, where the compiler injects a runtime check to each | |
749 | indirect function call to ensure the target is a valid function with | |
750 | the correct static type. This restricts possible call targets and | |
751 | makes it more difficult for an attacker to exploit bugs that allow | |
752 | the modification of stored function pointers. More information can be | |
753 | found from Clang's documentation: | |
754 | ||
755 | https://clang.llvm.org/docs/ControlFlowIntegrity.html | |
756 | ||
757 | config CFI_CLANG_SHADOW | |
758 | bool "Use CFI shadow to speed up cross-module checks" | |
759 | default y | |
760 | depends on CFI_CLANG && MODULES | |
761 | help | |
762 | If you select this option, the kernel builds a fast look-up table of | |
763 | CFI check functions in loaded modules to reduce performance overhead. | |
764 | ||
765 | If unsure, say Y. | |
766 | ||
767 | config CFI_PERMISSIVE | |
768 | bool "Use CFI in permissive mode" | |
769 | depends on CFI_CLANG | |
770 | help | |
771 | When selected, Control Flow Integrity (CFI) violations result in a | |
772 | warning instead of a kernel panic. This option should only be used | |
773 | for finding indirect call type mismatches during development. | |
774 | ||
775 | If unsure, say N. | |
776 | ||
0f60a8ef KC |
777 | config HAVE_ARCH_WITHIN_STACK_FRAMES |
778 | bool | |
779 | help | |
780 | An architecture should select this if it can walk the kernel stack | |
781 | frames to determine if an object is part of either the arguments | |
782 | or local variables (i.e. that it excludes saved return addresses, | |
783 | and similar) by implementing an inline arch_within_stack_frames(), | |
784 | which is used by CONFIG_HARDENED_USERCOPY. | |
785 | ||
24a9c541 | 786 | config HAVE_CONTEXT_TRACKING_USER |
2b1d5024 FW |
787 | bool |
788 | help | |
91d1aa43 FW |
789 | Provide kernel/user boundaries probes necessary for subsystems |
790 | that need it, such as userspace RCU extended quiescent state. | |
490f561b FW |
791 | Syscalls need to be wrapped inside user_exit()-user_enter(), either |
792 | optimized behind static key or through the slow path using TIF_NOHZ | |
793 | flag. Exceptions handlers must be wrapped as well. Irqs are already | |
6f0e6c15 | 794 | protected inside ct_irq_enter/ct_irq_exit() but preemption or signal |
490f561b FW |
795 | handling on irq exit still need to be protected. |
796 | ||
24a9c541 | 797 | config HAVE_CONTEXT_TRACKING_USER_OFFSTACK |
83c2da2e FW |
798 | bool |
799 | help | |
800 | Architecture neither relies on exception_enter()/exception_exit() | |
801 | nor on schedule_user(). Also preempt_schedule_notrace() and | |
802 | preempt_schedule_irq() can't be called in a preemptible section | |
803 | while context tracking is CONTEXT_USER. This feature reflects a sane | |
804 | entry implementation where the following requirements are met on | |
805 | critical entry code, ie: before user_exit() or after user_enter(): | |
806 | ||
807 | - Critical entry code isn't preemptible (or better yet: | |
808 | not interruptible). | |
493c1822 | 809 | - No use of RCU read side critical sections, unless ct_nmi_enter() |
83c2da2e FW |
810 | got called. |
811 | - No use of instrumentation, unless instrumentation_begin() got | |
812 | called. | |
813 | ||
490f561b FW |
814 | config HAVE_TIF_NOHZ |
815 | bool | |
816 | help | |
817 | Arch relies on TIF_NOHZ and syscall slow path to implement context | |
818 | tracking calls to user_enter()/user_exit(). | |
2b1d5024 | 819 | |
b952741c FW |
820 | config HAVE_VIRT_CPU_ACCOUNTING |
821 | bool | |
822 | ||
2b91ec9f FW |
823 | config HAVE_VIRT_CPU_ACCOUNTING_IDLE |
824 | bool | |
825 | help | |
826 | Architecture has its own way to account idle CPU time and therefore | |
827 | doesn't implement vtime_account_idle(). | |
828 | ||
40565b5a SG |
829 | config ARCH_HAS_SCALED_CPUTIME |
830 | bool | |
831 | ||
554b0004 KH |
832 | config HAVE_VIRT_CPU_ACCOUNTING_GEN |
833 | bool | |
834 | default y if 64BIT | |
835 | help | |
836 | With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. | |
837 | Before enabling this option, arch code must be audited | |
838 | to ensure there are no races in concurrent read/write of | |
839 | cputime_t. For example, reading/writing 64-bit cputime_t on | |
840 | some 32-bit arches may require multiple accesses, so proper | |
841 | locking is needed to protect against concurrent accesses. | |
842 | ||
fdf9c356 FW |
843 | config HAVE_IRQ_TIME_ACCOUNTING |
844 | bool | |
845 | help | |
846 | Archs need to ensure they use a high enough resolution clock to | |
847 | support irq time accounting and then call enable_sched_clock_irqtime(). | |
848 | ||
c49dd340 KS |
849 | config HAVE_MOVE_PUD |
850 | bool | |
851 | help | |
852 | Architectures that select this are able to move page tables at the | |
853 | PUD level. If there are only 3 page table levels, the move effectively | |
854 | happens at the PGD level. | |
855 | ||
2c91bd4a JFG |
856 | config HAVE_MOVE_PMD |
857 | bool | |
858 | help | |
859 | Archs that select this are able to move page tables at the PMD level. | |
860 | ||
15626062 GS |
861 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE |
862 | bool | |
863 | ||
a00cc7d9 MW |
864 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
865 | bool | |
866 | ||
0ddab1d2 TK |
867 | config HAVE_ARCH_HUGE_VMAP |
868 | bool | |
869 | ||
121e6f32 NP |
870 | # |
871 | # Archs that select this would be capable of PMD-sized vmaps (i.e., | |
559089e0 SL |
872 | # arch_vmap_pmd_supported() returns true). The VM_ALLOW_HUGE_VMAP flag |
873 | # must be used to enable allocations to use hugepages. | |
121e6f32 NP |
874 | # |
875 | config HAVE_ARCH_HUGE_VMALLOC | |
876 | depends on HAVE_ARCH_HUGE_VMAP | |
877 | bool | |
878 | ||
3876d4a3 AG |
879 | config ARCH_WANT_HUGE_PMD_SHARE |
880 | bool | |
881 | ||
0f8975ec PE |
882 | config HAVE_ARCH_SOFT_DIRTY |
883 | bool | |
884 | ||
786d35d4 DH |
885 | config HAVE_MOD_ARCH_SPECIFIC |
886 | bool | |
887 | help | |
888 | The arch uses struct mod_arch_specific to store data. Many arches | |
889 | just need a simple module loader without arch specific data - those | |
890 | should not enable this. | |
891 | ||
892 | config MODULES_USE_ELF_RELA | |
893 | bool | |
894 | help | |
895 | Modules only use ELF RELA relocations. Modules with ELF REL | |
896 | relocations will give an error. | |
897 | ||
898 | config MODULES_USE_ELF_REL | |
899 | bool | |
900 | help | |
901 | Modules only use ELF REL relocations. Modules with ELF RELA | |
902 | relocations will give an error. | |
903 | ||
01dc0386 CL |
904 | config ARCH_WANTS_MODULES_DATA_IN_VMALLOC |
905 | bool | |
906 | help | |
907 | For architectures like powerpc/32 which have constraints on module | |
908 | allocation and need to allocate module data outside of module area. | |
909 | ||
cc1f0274 FW |
910 | config HAVE_IRQ_EXIT_ON_IRQ_STACK |
911 | bool | |
912 | help | |
913 | Architecture doesn't only execute the irq handler on the irq stack | |
914 | but also irq_exit(). This way we can process softirqs on this irq | |
915 | stack instead of switching to a new one when we call __do_softirq() | |
916 | in the end of an hardirq. | |
917 | This spares a stack switch and improves cache usage on softirq | |
918 | processing. | |
919 | ||
cd1a41ce TG |
920 | config HAVE_SOFTIRQ_ON_OWN_STACK |
921 | bool | |
922 | help | |
923 | Architecture provides a function to run __do_softirq() on a | |
c226bc3c | 924 | separate stack. |
cd1a41ce | 925 | |
8cbb2b50 SAS |
926 | config SOFTIRQ_ON_OWN_STACK |
927 | def_bool HAVE_SOFTIRQ_ON_OWN_STACK && !PREEMPT_RT | |
928 | ||
12700c17 AB |
929 | config ALTERNATE_USER_ADDRESS_SPACE |
930 | bool | |
931 | help | |
932 | Architectures set this when the CPU uses separate address | |
933 | spaces for kernel and user space pointers. In this case, the | |
934 | access_ok() check on a __user pointer is skipped. | |
935 | ||
235a8f02 KS |
936 | config PGTABLE_LEVELS |
937 | int | |
938 | default 2 | |
939 | ||
2b68f6ca KC |
940 | config ARCH_HAS_ELF_RANDOMIZE |
941 | bool | |
942 | help | |
943 | An architecture supports choosing randomized locations for | |
944 | stack, mmap, brk, and ET_DYN. Defined functions: | |
945 | - arch_mmap_rnd() | |
204db6ed | 946 | - arch_randomize_brk() |
2b68f6ca | 947 | |
d07e2259 DC |
948 | config HAVE_ARCH_MMAP_RND_BITS |
949 | bool | |
950 | help | |
951 | An arch should select this symbol if it supports setting a variable | |
952 | number of bits for use in establishing the base address for mmap | |
953 | allocations, has MMU enabled and provides values for both: | |
954 | - ARCH_MMAP_RND_BITS_MIN | |
955 | - ARCH_MMAP_RND_BITS_MAX | |
956 | ||
5f56a5df JS |
957 | config HAVE_EXIT_THREAD |
958 | bool | |
959 | help | |
960 | An architecture implements exit_thread. | |
961 | ||
d07e2259 DC |
962 | config ARCH_MMAP_RND_BITS_MIN |
963 | int | |
964 | ||
965 | config ARCH_MMAP_RND_BITS_MAX | |
966 | int | |
967 | ||
968 | config ARCH_MMAP_RND_BITS_DEFAULT | |
969 | int | |
970 | ||
971 | config ARCH_MMAP_RND_BITS | |
972 | int "Number of bits to use for ASLR of mmap base address" if EXPERT | |
973 | range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX | |
974 | default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT | |
975 | default ARCH_MMAP_RND_BITS_MIN | |
976 | depends on HAVE_ARCH_MMAP_RND_BITS | |
977 | help | |
978 | This value can be used to select the number of bits to use to | |
979 | determine the random offset to the base address of vma regions | |
980 | resulting from mmap allocations. This value will be bounded | |
981 | by the architecture's minimum and maximum supported values. | |
982 | ||
983 | This value can be changed after boot using the | |
984 | /proc/sys/vm/mmap_rnd_bits tunable | |
985 | ||
986 | config HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
987 | bool | |
988 | help | |
989 | An arch should select this symbol if it supports running applications | |
990 | in compatibility mode, supports setting a variable number of bits for | |
991 | use in establishing the base address for mmap allocations, has MMU | |
992 | enabled and provides values for both: | |
993 | - ARCH_MMAP_RND_COMPAT_BITS_MIN | |
994 | - ARCH_MMAP_RND_COMPAT_BITS_MAX | |
995 | ||
996 | config ARCH_MMAP_RND_COMPAT_BITS_MIN | |
997 | int | |
998 | ||
999 | config ARCH_MMAP_RND_COMPAT_BITS_MAX | |
1000 | int | |
1001 | ||
1002 | config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
1003 | int | |
1004 | ||
1005 | config ARCH_MMAP_RND_COMPAT_BITS | |
1006 | int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT | |
1007 | range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX | |
1008 | default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
1009 | default ARCH_MMAP_RND_COMPAT_BITS_MIN | |
1010 | depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
1011 | help | |
1012 | This value can be used to select the number of bits to use to | |
1013 | determine the random offset to the base address of vma regions | |
1014 | resulting from mmap allocations for compatible applications This | |
1015 | value will be bounded by the architecture's minimum and maximum | |
1016 | supported values. | |
1017 | ||
1018 | This value can be changed after boot using the | |
1019 | /proc/sys/vm/mmap_rnd_compat_bits tunable | |
1020 | ||
1b028f78 DS |
1021 | config HAVE_ARCH_COMPAT_MMAP_BASES |
1022 | bool | |
1023 | help | |
1024 | This allows 64bit applications to invoke 32-bit mmap() syscall | |
1025 | and vice-versa 32-bit applications to call 64-bit mmap(). | |
1026 | Required for applications doing different bitness syscalls. | |
1027 | ||
1f0e290c GR |
1028 | config PAGE_SIZE_LESS_THAN_64KB |
1029 | def_bool y | |
1030 | depends on !ARM64_64K_PAGES | |
1031 | depends on !IA64_PAGE_SIZE_64KB | |
1032 | depends on !PAGE_SIZE_64KB | |
1033 | depends on !PARISC_PAGE_SIZE_64KB | |
e4bbd20d NC |
1034 | depends on PAGE_SIZE_LESS_THAN_256KB |
1035 | ||
1036 | config PAGE_SIZE_LESS_THAN_256KB | |
1037 | def_bool y | |
1f0e290c GR |
1038 | depends on !PAGE_SIZE_256KB |
1039 | ||
67f3977f AG |
1040 | # This allows to use a set of generic functions to determine mmap base |
1041 | # address by giving priority to top-down scheme only if the process | |
1042 | # is not in legacy mode (compat task, unlimited stack size or | |
1043 | # sysctl_legacy_va_layout). | |
1044 | # Architecture that selects this option can provide its own version of: | |
1045 | # - STACK_RND_MASK | |
1046 | config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT | |
1047 | bool | |
1048 | depends on MMU | |
e7142bf5 | 1049 | select ARCH_HAS_ELF_RANDOMIZE |
67f3977f | 1050 | |
03f16cd0 JP |
1051 | config HAVE_OBJTOOL |
1052 | bool | |
1053 | ||
4ab7674f JP |
1054 | config HAVE_JUMP_LABEL_HACK |
1055 | bool | |
1056 | ||
22102f45 JP |
1057 | config HAVE_NOINSTR_HACK |
1058 | bool | |
1059 | ||
489e355b JP |
1060 | config HAVE_NOINSTR_VALIDATION |
1061 | bool | |
1062 | ||
5f3da8c0 JP |
1063 | config HAVE_UACCESS_VALIDATION |
1064 | bool | |
1065 | select OBJTOOL | |
1066 | ||
b9ab5ebb JP |
1067 | config HAVE_STACK_VALIDATION |
1068 | bool | |
1069 | help | |
03f16cd0 JP |
1070 | Architecture supports objtool compile-time frame pointer rule |
1071 | validation. | |
b9ab5ebb | 1072 | |
af085d90 JP |
1073 | config HAVE_RELIABLE_STACKTRACE |
1074 | bool | |
1075 | help | |
140d7e88 MB |
1076 | Architecture has either save_stack_trace_tsk_reliable() or |
1077 | arch_stack_walk_reliable() function which only returns a stack trace | |
1078 | if it can guarantee the trace is reliable. | |
af085d90 | 1079 | |
468a9428 GS |
1080 | config HAVE_ARCH_HASH |
1081 | bool | |
1082 | default n | |
1083 | help | |
1084 | If this is set, the architecture provides an <asm/hash.h> | |
1085 | file which provides platform-specific implementations of some | |
1086 | functions in <linux/hash.h> or fs/namei.c. | |
1087 | ||
666047fe FT |
1088 | config HAVE_ARCH_NVRAM_OPS |
1089 | bool | |
1090 | ||
3a495511 WBG |
1091 | config ISA_BUS_API |
1092 | def_bool ISA | |
1093 | ||
d2125043 AV |
1094 | # |
1095 | # ABI hall of shame | |
1096 | # | |
1097 | config CLONE_BACKWARDS | |
1098 | bool | |
1099 | help | |
1100 | Architecture has tls passed as the 4th argument of clone(2), | |
1101 | not the 5th one. | |
1102 | ||
1103 | config CLONE_BACKWARDS2 | |
1104 | bool | |
1105 | help | |
1106 | Architecture has the first two arguments of clone(2) swapped. | |
1107 | ||
dfa9771a MS |
1108 | config CLONE_BACKWARDS3 |
1109 | bool | |
1110 | help | |
1111 | Architecture has tls passed as the 3rd argument of clone(2), | |
1112 | not the 5th one. | |
1113 | ||
eaca6eae AV |
1114 | config ODD_RT_SIGACTION |
1115 | bool | |
1116 | help | |
1117 | Architecture has unusual rt_sigaction(2) arguments | |
1118 | ||
0a0e8cdf AV |
1119 | config OLD_SIGSUSPEND |
1120 | bool | |
1121 | help | |
1122 | Architecture has old sigsuspend(2) syscall, of one-argument variety | |
1123 | ||
1124 | config OLD_SIGSUSPEND3 | |
1125 | bool | |
1126 | help | |
1127 | Even weirder antique ABI - three-argument sigsuspend(2) | |
1128 | ||
495dfbf7 AV |
1129 | config OLD_SIGACTION |
1130 | bool | |
1131 | help | |
1132 | Architecture has old sigaction(2) syscall. Nope, not the same | |
1133 | as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), | |
1134 | but fairly different variant of sigaction(2), thanks to OSF/1 | |
1135 | compatibility... | |
1136 | ||
1137 | config COMPAT_OLD_SIGACTION | |
1138 | bool | |
1139 | ||
17435e5f | 1140 | config COMPAT_32BIT_TIME |
942437c9 AB |
1141 | bool "Provide system calls for 32-bit time_t" |
1142 | default !64BIT || COMPAT | |
17435e5f DD |
1143 | help |
1144 | This enables 32 bit time_t support in addition to 64 bit time_t support. | |
1145 | This is relevant on all 32-bit architectures, and 64-bit architectures | |
1146 | as part of compat syscall handling. | |
1147 | ||
87a4c375 CH |
1148 | config ARCH_NO_PREEMPT |
1149 | bool | |
1150 | ||
cb2c7d1a MS |
1151 | config ARCH_EPHEMERAL_INODES |
1152 | def_bool n | |
1153 | help | |
1154 | An arch should select this symbol if it doesn't keep track of inode | |
1155 | instances on its own, but instead relies on something else (e.g. the | |
1156 | host kernel for an UML kernel). | |
1157 | ||
a50a3f4b TG |
1158 | config ARCH_SUPPORTS_RT |
1159 | bool | |
1160 | ||
fff7fb0b ZZ |
1161 | config CPU_NO_EFFICIENT_FFS |
1162 | def_bool n | |
1163 | ||
ba14a194 AL |
1164 | config HAVE_ARCH_VMAP_STACK |
1165 | def_bool n | |
1166 | help | |
1167 | An arch should select this symbol if it can support kernel stacks | |
1168 | in vmalloc space. This means: | |
1169 | ||
1170 | - vmalloc space must be large enough to hold many kernel stacks. | |
1171 | This may rule out many 32-bit architectures. | |
1172 | ||
1173 | - Stacks in vmalloc space need to work reliably. For example, if | |
1174 | vmap page tables are created on demand, either this mechanism | |
1175 | needs to work while the stack points to a virtual address with | |
1176 | unpopulated page tables or arch code (switch_to() and switch_mm(), | |
1177 | most likely) needs to ensure that the stack's page table entries | |
1178 | are populated before running on a possibly unpopulated stack. | |
1179 | ||
1180 | - If the stack overflows into a guard page, something reasonable | |
1181 | should happen. The definition of "reasonable" is flexible, but | |
1182 | instantly rebooting without logging anything would be unfriendly. | |
1183 | ||
1184 | config VMAP_STACK | |
1185 | default y | |
1186 | bool "Use a virtually-mapped stack" | |
eafb149e | 1187 | depends on HAVE_ARCH_VMAP_STACK |
38dd767d | 1188 | depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC |
a7f7f624 | 1189 | help |
ba14a194 AL |
1190 | Enable this if you want the use virtually-mapped kernel stacks |
1191 | with guard pages. This causes kernel stack overflows to be | |
1192 | caught immediately rather than causing difficult-to-diagnose | |
1193 | corruption. | |
1194 | ||
38dd767d AK |
1195 | To use this with software KASAN modes, the architecture must support |
1196 | backing virtual mappings with real shadow memory, and KASAN_VMALLOC | |
1197 | must be enabled. | |
ba14a194 | 1198 | |
39218ff4 KC |
1199 | config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET |
1200 | def_bool n | |
1201 | help | |
1202 | An arch should select this symbol if it can support kernel stack | |
1203 | offset randomization with calls to add_random_kstack_offset() | |
1204 | during syscall entry and choose_random_kstack_offset() during | |
1205 | syscall exit. Careful removal of -fstack-protector-strong and | |
1206 | -fstack-protector should also be applied to the entry code and | |
1207 | closely examined, as the artificial stack bump looks like an array | |
1208 | to the compiler, so it will attempt to add canary checks regardless | |
1209 | of the static branch state. | |
1210 | ||
8cb37a59 ME |
1211 | config RANDOMIZE_KSTACK_OFFSET |
1212 | bool "Support for randomizing kernel stack offset on syscall entry" if EXPERT | |
1213 | default y | |
39218ff4 | 1214 | depends on HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET |
efa90c11 | 1215 | depends on INIT_STACK_NONE || !CC_IS_CLANG || CLANG_VERSION >= 140000 |
39218ff4 KC |
1216 | help |
1217 | The kernel stack offset can be randomized (after pt_regs) by | |
1218 | roughly 5 bits of entropy, frustrating memory corruption | |
1219 | attacks that depend on stack address determinism or | |
8cb37a59 ME |
1220 | cross-syscall address exposures. |
1221 | ||
1222 | The feature is controlled via the "randomize_kstack_offset=on/off" | |
1223 | kernel boot param, and if turned off has zero overhead due to its use | |
1224 | of static branches (see JUMP_LABEL). | |
1225 | ||
1226 | If unsure, say Y. | |
1227 | ||
1228 | config RANDOMIZE_KSTACK_OFFSET_DEFAULT | |
1229 | bool "Default state of kernel stack offset randomization" | |
1230 | depends on RANDOMIZE_KSTACK_OFFSET | |
1231 | help | |
1232 | Kernel stack offset randomization is controlled by kernel boot param | |
1233 | "randomize_kstack_offset=on/off", and this config chooses the default | |
1234 | boot state. | |
39218ff4 | 1235 | |
ad21fc4f LA |
1236 | config ARCH_OPTIONAL_KERNEL_RWX |
1237 | def_bool n | |
1238 | ||
1239 | config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
1240 | def_bool n | |
1241 | ||
1242 | config ARCH_HAS_STRICT_KERNEL_RWX | |
1243 | def_bool n | |
1244 | ||
0f5bf6d0 | 1245 | config STRICT_KERNEL_RWX |
ad21fc4f LA |
1246 | bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX |
1247 | depends on ARCH_HAS_STRICT_KERNEL_RWX | |
1248 | default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
1249 | help | |
1250 | If this is set, kernel text and rodata memory will be made read-only, | |
1251 | and non-text memory will be made non-executable. This provides | |
1252 | protection against certain security exploits (e.g. executing the heap | |
1253 | or modifying text) | |
1254 | ||
1255 | These features are considered standard security practice these days. | |
1256 | You should say Y here in almost all cases. | |
1257 | ||
1258 | config ARCH_HAS_STRICT_MODULE_RWX | |
1259 | def_bool n | |
1260 | ||
0f5bf6d0 | 1261 | config STRICT_MODULE_RWX |
ad21fc4f LA |
1262 | bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX |
1263 | depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES | |
1264 | default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
1265 | help | |
1266 | If this is set, module text and rodata memory will be made read-only, | |
1267 | and non-text memory will be made non-executable. This provides | |
1268 | protection against certain security exploits (e.g. writing to text) | |
1269 | ||
ea8c64ac CH |
1270 | # select if the architecture provides an asm/dma-direct.h header |
1271 | config ARCH_HAS_PHYS_TO_DMA | |
1272 | bool | |
1273 | ||
04f264d3 PB |
1274 | config HAVE_ARCH_COMPILER_H |
1275 | bool | |
1276 | help | |
1277 | An architecture can select this if it provides an | |
1278 | asm/compiler.h header that should be included after | |
1279 | linux/compiler-*.h in order to override macro definitions that those | |
1280 | headers generally provide. | |
1281 | ||
271ca788 AB |
1282 | config HAVE_ARCH_PREL32_RELOCATIONS |
1283 | bool | |
1284 | help | |
1285 | May be selected by an architecture if it supports place-relative | |
1286 | 32-bit relocations, both in the toolchain and in the module loader, | |
1287 | in which case relative references can be used in special sections | |
1288 | for PCI fixup, initcalls etc which are only half the size on 64 bit | |
1289 | architectures, and don't require runtime relocation on relocatable | |
1290 | kernels. | |
1291 | ||
ce9084ba AB |
1292 | config ARCH_USE_MEMREMAP_PROT |
1293 | bool | |
1294 | ||
fb346fd9 WL |
1295 | config LOCK_EVENT_COUNTS |
1296 | bool "Locking event counts collection" | |
1297 | depends on DEBUG_FS | |
a7f7f624 | 1298 | help |
fb346fd9 WL |
1299 | Enable light-weight counting of various locking related events |
1300 | in the system with minimal performance impact. This reduces | |
1301 | the chance of application behavior change because of timing | |
1302 | differences. The counts are reported via debugfs. | |
1303 | ||
5cf896fb PC |
1304 | # Select if the architecture has support for applying RELR relocations. |
1305 | config ARCH_HAS_RELR | |
1306 | bool | |
1307 | ||
1308 | config RELR | |
1309 | bool "Use RELR relocation packing" | |
1310 | depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR | |
1311 | default y | |
1312 | help | |
1313 | Store the kernel's dynamic relocations in the RELR relocation packing | |
1314 | format. Requires a compatible linker (LLD supports this feature), as | |
1315 | well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy | |
1316 | are compatible). | |
1317 | ||
0c9c1d56 TJB |
1318 | config ARCH_HAS_MEM_ENCRYPT |
1319 | bool | |
1320 | ||
46b49b12 TL |
1321 | config ARCH_HAS_CC_PLATFORM |
1322 | bool | |
1323 | ||
0e242208 HN |
1324 | config HAVE_SPARSE_SYSCALL_NR |
1325 | bool | |
1326 | help | |
1327 | An architecture should select this if its syscall numbering is sparse | |
1328 | to save space. For example, MIPS architecture has a syscall array with | |
1329 | entries at 4000, 5000 and 6000 locations. This option turns on syscall | |
1330 | related optimizations for a given architecture. | |
1331 | ||
d60d7de3 SS |
1332 | config ARCH_HAS_VDSO_DATA |
1333 | bool | |
1334 | ||
115284d8 JP |
1335 | config HAVE_STATIC_CALL |
1336 | bool | |
1337 | ||
9183c3f9 JP |
1338 | config HAVE_STATIC_CALL_INLINE |
1339 | bool | |
1340 | depends on HAVE_STATIC_CALL | |
03f16cd0 | 1341 | select OBJTOOL |
9183c3f9 | 1342 | |
6ef869e0 MH |
1343 | config HAVE_PREEMPT_DYNAMIC |
1344 | bool | |
99cf983c MR |
1345 | |
1346 | config HAVE_PREEMPT_DYNAMIC_CALL | |
1347 | bool | |
6ef869e0 | 1348 | depends on HAVE_STATIC_CALL |
99cf983c MR |
1349 | select HAVE_PREEMPT_DYNAMIC |
1350 | help | |
1351 | An architecture should select this if it can handle the preemption | |
1352 | model being selected at boot time using static calls. | |
1353 | ||
1354 | Where an architecture selects HAVE_STATIC_CALL_INLINE, any call to a | |
1355 | preemption function will be patched directly. | |
1356 | ||
1357 | Where an architecture does not select HAVE_STATIC_CALL_INLINE, any | |
1358 | call to a preemption function will go through a trampoline, and the | |
1359 | trampoline will be patched. | |
1360 | ||
1361 | It is strongly advised to support inline static call to avoid any | |
1362 | overhead. | |
1363 | ||
1364 | config HAVE_PREEMPT_DYNAMIC_KEY | |
1365 | bool | |
a0a12c3e | 1366 | depends on HAVE_ARCH_JUMP_LABEL |
99cf983c | 1367 | select HAVE_PREEMPT_DYNAMIC |
6ef869e0 | 1368 | help |
99cf983c MR |
1369 | An architecture should select this if it can handle the preemption |
1370 | model being selected at boot time using static keys. | |
1371 | ||
1372 | Each preemption function will be given an early return based on a | |
1373 | static key. This should have slightly lower overhead than non-inline | |
1374 | static calls, as this effectively inlines each trampoline into the | |
1375 | start of its callee. This may avoid redundant work, and may | |
1376 | integrate better with CFI schemes. | |
1377 | ||
1378 | This will have greater overhead than using inline static calls as | |
1379 | the call to the preemption function cannot be entirely elided. | |
6ef869e0 | 1380 | |
59612b24 NC |
1381 | config ARCH_WANT_LD_ORPHAN_WARN |
1382 | bool | |
1383 | help | |
1384 | An arch should select this symbol once all linker sections are explicitly | |
1385 | included, size-asserted, or discarded in the linker scripts. This is | |
1386 | important because we never want expected sections to be placed heuristically | |
1387 | by the linker, since the locations of such sections can change between linker | |
1388 | versions. | |
1389 | ||
4f5b0c17 MR |
1390 | config HAVE_ARCH_PFN_VALID |
1391 | bool | |
1392 | ||
5d6ad668 MR |
1393 | config ARCH_SUPPORTS_DEBUG_PAGEALLOC |
1394 | bool | |
1395 | ||
df4e817b PT |
1396 | config ARCH_SUPPORTS_PAGE_TABLE_CHECK |
1397 | bool | |
1398 | ||
2ca408d9 BG |
1399 | config ARCH_SPLIT_ARG64 |
1400 | bool | |
1401 | help | |
1402 | If a 32-bit architecture requires 64-bit arguments to be split into | |
1403 | pairs of 32-bit arguments, select this option. | |
1404 | ||
7facdc42 AV |
1405 | config ARCH_HAS_ELFCORE_COMPAT |
1406 | bool | |
1407 | ||
58e106e7 BS |
1408 | config ARCH_HAS_PARANOID_L1D_FLUSH |
1409 | bool | |
1410 | ||
d593d64f PS |
1411 | config ARCH_HAVE_TRACE_MMIO_ACCESS |
1412 | bool | |
1413 | ||
1bdda24c TG |
1414 | config DYNAMIC_SIGFRAME |
1415 | bool | |
1416 | ||
50468e43 JS |
1417 | # Select, if arch has a named attribute group bound to NUMA device nodes. |
1418 | config HAVE_ARCH_NODE_DEV_GROUP | |
1419 | bool | |
1420 | ||
2521f2c2 | 1421 | source "kernel/gcov/Kconfig" |
45332b1b MY |
1422 | |
1423 | source "scripts/gcc-plugins/Kconfig" | |
fa1b5d09 | 1424 | |
22471e13 | 1425 | endmenu |