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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 | |
692f66f2 HB |
6 | config CRASH_CORE |
7 | bool | |
8 | ||
2965faa5 | 9 | config KEXEC_CORE |
692f66f2 | 10 | select CRASH_CORE |
2965faa5 DY |
11 | bool |
12 | ||
467d2782 TJB |
13 | config HAVE_IMA_KEXEC |
14 | bool | |
15 | ||
125e5645 | 16 | config OPROFILE |
b309a294 | 17 | tristate "OProfile system profiling" |
125e5645 MD |
18 | depends on PROFILING |
19 | depends on HAVE_OPROFILE | |
d69d59f4 | 20 | select RING_BUFFER |
9a5963eb | 21 | select RING_BUFFER_ALLOW_SWAP |
125e5645 MD |
22 | help |
23 | OProfile is a profiling system capable of profiling the | |
24 | whole system, include the kernel, kernel modules, libraries, | |
25 | and applications. | |
26 | ||
27 | If unsure, say N. | |
28 | ||
4d4036e0 JY |
29 | config OPROFILE_EVENT_MULTIPLEX |
30 | bool "OProfile multiplexing support (EXPERIMENTAL)" | |
31 | default n | |
32 | depends on OPROFILE && X86 | |
33 | help | |
34 | The number of hardware counters is limited. The multiplexing | |
35 | feature enables OProfile to gather more events than counters | |
36 | are provided by the hardware. This is realized by switching | |
9332ef9d | 37 | between events at a user specified time interval. |
4d4036e0 JY |
38 | |
39 | If unsure, say N. | |
40 | ||
125e5645 | 41 | config HAVE_OPROFILE |
9ba16087 | 42 | bool |
125e5645 | 43 | |
dcfce4a0 RR |
44 | config OPROFILE_NMI_TIMER |
45 | def_bool y | |
af9feebe | 46 | depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64 |
dcfce4a0 | 47 | |
125e5645 MD |
48 | config KPROBES |
49 | bool "Kprobes" | |
05ed160e | 50 | depends on MODULES |
125e5645 | 51 | depends on HAVE_KPROBES |
05ed160e | 52 | select KALLSYMS |
125e5645 MD |
53 | help |
54 | Kprobes allows you to trap at almost any kernel address and | |
55 | execute a callback function. register_kprobe() establishes | |
56 | a probepoint and specifies the callback. Kprobes is useful | |
57 | for kernel debugging, non-intrusive instrumentation and testing. | |
58 | If in doubt, say "N". | |
59 | ||
45f81b1c | 60 | config JUMP_LABEL |
c5905afb | 61 | bool "Optimize very unlikely/likely branches" |
45f81b1c SR |
62 | depends on HAVE_ARCH_JUMP_LABEL |
63 | help | |
c5905afb IM |
64 | This option enables a transparent branch optimization that |
65 | makes certain almost-always-true or almost-always-false branch | |
66 | conditions even cheaper to execute within the kernel. | |
67 | ||
68 | Certain performance-sensitive kernel code, such as trace points, | |
69 | scheduler functionality, networking code and KVM have such | |
70 | branches and include support for this optimization technique. | |
71 | ||
45f81b1c | 72 | If it is detected that the compiler has support for "asm goto", |
c5905afb IM |
73 | the kernel will compile such branches with just a nop |
74 | instruction. When the condition flag is toggled to true, the | |
75 | nop will be converted to a jump instruction to execute the | |
76 | conditional block of instructions. | |
77 | ||
78 | This technique lowers overhead and stress on the branch prediction | |
79 | of the processor and generally makes the kernel faster. The update | |
80 | of the condition is slower, but those are always very rare. | |
45f81b1c | 81 | |
c5905afb IM |
82 | ( On 32-bit x86, the necessary options added to the compiler |
83 | flags may increase the size of the kernel slightly. ) | |
45f81b1c | 84 | |
1987c947 PZ |
85 | config STATIC_KEYS_SELFTEST |
86 | bool "Static key selftest" | |
87 | depends on JUMP_LABEL | |
88 | help | |
89 | Boot time self-test of the branch patching code. | |
90 | ||
afd66255 | 91 | config OPTPROBES |
5cc718b9 MH |
92 | def_bool y |
93 | depends on KPROBES && HAVE_OPTPROBES | |
a30b85df | 94 | select TASKS_RCU if PREEMPT |
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 | |
c19fa94a JH |
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 | ||
132 | See Documentation/unaligned-memory-access.txt for more | |
133 | information on the topic of unaligned memory accesses. | |
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 | ||
151 | See Documentation/unaligned-memory-access.txt for more | |
152 | information on the topic of unaligned memory accesses. | |
153 | ||
cf66bb93 DW |
154 | config ARCH_USE_BUILTIN_BSWAP |
155 | bool | |
156 | help | |
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 | |
175 | depends on KPROBES && HAVE_KRETPROBES | |
176 | ||
7c68af6e AK |
177 | config USER_RETURN_NOTIFIER |
178 | bool | |
179 | depends on HAVE_USER_RETURN_NOTIFIER | |
180 | help | |
181 | Provide a kernel-internal notification when a cpu is about to | |
182 | switch to user mode. | |
183 | ||
28b2ee20 | 184 | config HAVE_IOREMAP_PROT |
9ba16087 | 185 | bool |
28b2ee20 | 186 | |
125e5645 | 187 | config HAVE_KPROBES |
9ba16087 | 188 | bool |
9edddaa2 AM |
189 | |
190 | config HAVE_KRETPROBES | |
9ba16087 | 191 | bool |
74bc7cee | 192 | |
afd66255 MH |
193 | config HAVE_OPTPROBES |
194 | bool | |
d314d74c | 195 | |
e7dbfe34 MH |
196 | config HAVE_KPROBES_ON_FTRACE |
197 | bool | |
198 | ||
540adea3 | 199 | config HAVE_FUNCTION_ERROR_INJECTION |
9802d865 JB |
200 | bool |
201 | ||
42a0bb3f PM |
202 | config HAVE_NMI |
203 | bool | |
204 | ||
1f5a4ad9 RM |
205 | # |
206 | # An arch should select this if it provides all these things: | |
207 | # | |
208 | # task_pt_regs() in asm/processor.h or asm/ptrace.h | |
209 | # arch_has_single_step() if there is hardware single-step support | |
210 | # arch_has_block_step() if there is hardware block-step support | |
1f5a4ad9 RM |
211 | # asm/syscall.h supplying asm-generic/syscall.h interface |
212 | # linux/regset.h user_regset interfaces | |
213 | # CORE_DUMP_USE_REGSET #define'd in linux/elf.h | |
214 | # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} | |
215 | # TIF_NOTIFY_RESUME calls tracehook_notify_resume() | |
216 | # signal delivery calls tracehook_signal_handler() | |
217 | # | |
218 | config HAVE_ARCH_TRACEHOOK | |
9ba16087 | 219 | bool |
1f5a4ad9 | 220 | |
c64be2bb MS |
221 | config HAVE_DMA_CONTIGUOUS |
222 | bool | |
223 | ||
29d5e047 TG |
224 | config GENERIC_SMP_IDLE_THREAD |
225 | bool | |
226 | ||
485cf5da KH |
227 | config GENERIC_IDLE_POLL_SETUP |
228 | bool | |
229 | ||
6974f0c4 DM |
230 | config ARCH_HAS_FORTIFY_SOURCE |
231 | bool | |
232 | help | |
233 | An architecture should select this when it can successfully | |
234 | build and run with CONFIG_FORTIFY_SOURCE. | |
235 | ||
d2852a22 DB |
236 | # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h |
237 | config ARCH_HAS_SET_MEMORY | |
238 | bool | |
239 | ||
0500871f DH |
240 | # Select if arch init_task must go in the __init_task_data section |
241 | config ARCH_TASK_STRUCT_ON_STACK | |
a4a2eb49 TG |
242 | bool |
243 | ||
f5e10287 TG |
244 | # Select if arch has its private alloc_task_struct() function |
245 | config ARCH_TASK_STRUCT_ALLOCATOR | |
246 | bool | |
247 | ||
5905429a KC |
248 | config HAVE_ARCH_THREAD_STRUCT_WHITELIST |
249 | bool | |
250 | depends on !ARCH_TASK_STRUCT_ALLOCATOR | |
251 | help | |
252 | An architecture should select this to provide hardened usercopy | |
253 | knowledge about what region of the thread_struct should be | |
254 | whitelisted for copying to userspace. Normally this is only the | |
255 | FPU registers. Specifically, arch_thread_struct_whitelist() | |
256 | should be implemented. Without this, the entire thread_struct | |
257 | field in task_struct will be left whitelisted. | |
258 | ||
b235beea LT |
259 | # Select if arch has its private alloc_thread_stack() function |
260 | config ARCH_THREAD_STACK_ALLOCATOR | |
f5e10287 TG |
261 | bool |
262 | ||
5aaeb5c0 IM |
263 | # Select if arch wants to size task_struct dynamically via arch_task_struct_size: |
264 | config ARCH_WANTS_DYNAMIC_TASK_STRUCT | |
265 | bool | |
266 | ||
f850c30c HC |
267 | config HAVE_REGS_AND_STACK_ACCESS_API |
268 | bool | |
e01292b1 HC |
269 | help |
270 | This symbol should be selected by an architecure if it supports | |
271 | the API needed to access registers and stack entries from pt_regs, | |
272 | declared in asm/ptrace.h | |
273 | For example the kprobes-based event tracer needs this API. | |
f850c30c | 274 | |
d7822b1e MD |
275 | config HAVE_RSEQ |
276 | bool | |
277 | depends on HAVE_REGS_AND_STACK_ACCESS_API | |
278 | help | |
279 | This symbol should be selected by an architecture if it | |
280 | supports an implementation of restartable sequences. | |
281 | ||
9483a578 | 282 | config HAVE_CLK |
9ba16087 | 283 | bool |
9483a578 DB |
284 | help |
285 | The <linux/clk.h> calls support software clock gating and | |
286 | thus are a key power management tool on many systems. | |
287 | ||
62a038d3 P |
288 | config HAVE_HW_BREAKPOINT |
289 | bool | |
99e8c5a3 | 290 | depends on PERF_EVENTS |
62a038d3 | 291 | |
0102752e FW |
292 | config HAVE_MIXED_BREAKPOINTS_REGS |
293 | bool | |
294 | depends on HAVE_HW_BREAKPOINT | |
295 | help | |
296 | Depending on the arch implementation of hardware breakpoints, | |
297 | some of them have separate registers for data and instruction | |
298 | breakpoints addresses, others have mixed registers to store | |
299 | them but define the access type in a control register. | |
300 | Select this option if your arch implements breakpoints under the | |
301 | latter fashion. | |
302 | ||
7c68af6e AK |
303 | config HAVE_USER_RETURN_NOTIFIER |
304 | bool | |
a1922ed6 | 305 | |
c01d4323 FW |
306 | config HAVE_PERF_EVENTS_NMI |
307 | bool | |
23637d47 FW |
308 | help |
309 | System hardware can generate an NMI using the perf event | |
310 | subsystem. Also has support for calculating CPU cycle events | |
311 | to determine how many clock cycles in a given period. | |
c01d4323 | 312 | |
05a4a952 NP |
313 | config HAVE_HARDLOCKUP_DETECTOR_PERF |
314 | bool | |
315 | depends on HAVE_PERF_EVENTS_NMI | |
316 | help | |
317 | The arch chooses to use the generic perf-NMI-based hardlockup | |
318 | detector. Must define HAVE_PERF_EVENTS_NMI. | |
319 | ||
320 | config HAVE_NMI_WATCHDOG | |
321 | depends on HAVE_NMI | |
322 | bool | |
323 | help | |
324 | The arch provides a low level NMI watchdog. It provides | |
325 | asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). | |
326 | ||
327 | config HAVE_HARDLOCKUP_DETECTOR_ARCH | |
328 | bool | |
329 | select HAVE_NMI_WATCHDOG | |
330 | help | |
331 | The arch chooses to provide its own hardlockup detector, which is | |
332 | a superset of the HAVE_NMI_WATCHDOG. It also conforms to config | |
333 | interfaces and parameters provided by hardlockup detector subsystem. | |
334 | ||
c5e63197 JO |
335 | config HAVE_PERF_REGS |
336 | bool | |
337 | help | |
338 | Support selective register dumps for perf events. This includes | |
339 | bit-mapping of each registers and a unique architecture id. | |
340 | ||
c5ebcedb JO |
341 | config HAVE_PERF_USER_STACK_DUMP |
342 | bool | |
343 | help | |
344 | Support user stack dumps for perf event samples. This needs | |
345 | access to the user stack pointer which is not unified across | |
346 | architectures. | |
347 | ||
bf5438fc JB |
348 | config HAVE_ARCH_JUMP_LABEL |
349 | bool | |
350 | ||
26723911 PZ |
351 | config HAVE_RCU_TABLE_FREE |
352 | bool | |
353 | ||
df013ffb HY |
354 | config ARCH_HAVE_NMI_SAFE_CMPXCHG |
355 | bool | |
356 | ||
43570fd2 HC |
357 | config HAVE_ALIGNED_STRUCT_PAGE |
358 | bool | |
359 | help | |
360 | This makes sure that struct pages are double word aligned and that | |
361 | e.g. the SLUB allocator can perform double word atomic operations | |
362 | on a struct page for better performance. However selecting this | |
363 | might increase the size of a struct page by a word. | |
364 | ||
4156153c HC |
365 | config HAVE_CMPXCHG_LOCAL |
366 | bool | |
367 | ||
2565409f HC |
368 | config HAVE_CMPXCHG_DOUBLE |
369 | bool | |
370 | ||
77e58496 PM |
371 | config ARCH_WEAK_RELEASE_ACQUIRE |
372 | bool | |
373 | ||
c1d7e01d WD |
374 | config ARCH_WANT_IPC_PARSE_VERSION |
375 | bool | |
376 | ||
377 | config ARCH_WANT_COMPAT_IPC_PARSE_VERSION | |
378 | bool | |
379 | ||
48b25c43 | 380 | config ARCH_WANT_OLD_COMPAT_IPC |
c1d7e01d | 381 | select ARCH_WANT_COMPAT_IPC_PARSE_VERSION |
48b25c43 CM |
382 | bool |
383 | ||
e2cfabdf WD |
384 | config HAVE_ARCH_SECCOMP_FILTER |
385 | bool | |
386 | help | |
fb0fadf9 | 387 | An arch should select this symbol if it provides all of these things: |
bb6ea430 WD |
388 | - syscall_get_arch() |
389 | - syscall_get_arguments() | |
390 | - syscall_rollback() | |
391 | - syscall_set_return_value() | |
fb0fadf9 WD |
392 | - SIGSYS siginfo_t support |
393 | - secure_computing is called from a ptrace_event()-safe context | |
394 | - secure_computing return value is checked and a return value of -1 | |
395 | results in the system call being skipped immediately. | |
48dc92b9 | 396 | - seccomp syscall wired up |
e2cfabdf WD |
397 | |
398 | config SECCOMP_FILTER | |
399 | def_bool y | |
400 | depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET | |
401 | help | |
402 | Enable tasks to build secure computing environments defined | |
403 | in terms of Berkeley Packet Filter programs which implement | |
404 | task-defined system call filtering polices. | |
405 | ||
5fb94e9c | 406 | See Documentation/userspace-api/seccomp_filter.rst for details. |
e2cfabdf | 407 | |
59f53855 MY |
408 | preferred-plugin-hostcc := $(if-success,[ $(gcc-version) -ge 40800 ],$(HOSTCXX),$(HOSTCC)) |
409 | ||
410 | config PLUGIN_HOSTCC | |
411 | string | |
412 | default "$(shell,$(srctree)/scripts/gcc-plugin.sh "$(preferred-plugin-hostcc)" "$(HOSTCXX)" "$(CC)")" | |
413 | help | |
414 | Host compiler used to build GCC plugins. This can be $(HOSTCXX), | |
415 | $(HOSTCC), or a null string if GCC plugin is unsupported. | |
416 | ||
6b90bd4b ER |
417 | config HAVE_GCC_PLUGINS |
418 | bool | |
419 | help | |
420 | An arch should select this symbol if it supports building with | |
421 | GCC plugins. | |
422 | ||
423 | menuconfig GCC_PLUGINS | |
424 | bool "GCC plugins" | |
425 | depends on HAVE_GCC_PLUGINS | |
59f53855 | 426 | depends on PLUGIN_HOSTCC != "" |
6b90bd4b ER |
427 | help |
428 | GCC plugins are loadable modules that provide extra features to the | |
429 | compiler. They are useful for runtime instrumentation and static analysis. | |
430 | ||
431 | See Documentation/gcc-plugins.txt for details. | |
432 | ||
0dae776c | 433 | config GCC_PLUGIN_CYC_COMPLEXITY |
215e2aa6 | 434 | bool "Compute the cyclomatic complexity of a function" if EXPERT |
0dae776c | 435 | depends on GCC_PLUGINS |
1658dcee | 436 | depends on !COMPILE_TEST # too noisy |
0dae776c ER |
437 | help |
438 | The complexity M of a function's control flow graph is defined as: | |
439 | M = E - N + 2P | |
440 | where | |
441 | ||
442 | E = the number of edges | |
443 | N = the number of nodes | |
444 | P = the number of connected components (exit nodes). | |
445 | ||
215e2aa6 KC |
446 | Enabling this plugin reports the complexity to stderr during the |
447 | build. It mainly serves as a simple example of how to create a | |
448 | gcc plugin for the kernel. | |
449 | ||
543c37cb ER |
450 | config GCC_PLUGIN_SANCOV |
451 | bool | |
452 | depends on GCC_PLUGINS | |
453 | help | |
454 | This plugin inserts a __sanitizer_cov_trace_pc() call at the start of | |
455 | basic blocks. It supports all gcc versions with plugin support (from | |
456 | gcc-4.5 on). It is based on the commit "Add fuzzing coverage support" | |
457 | by Dmitry Vyukov <dvyukov@google.com>. | |
458 | ||
38addce8 ER |
459 | config GCC_PLUGIN_LATENT_ENTROPY |
460 | bool "Generate some entropy during boot and runtime" | |
461 | depends on GCC_PLUGINS | |
462 | help | |
463 | By saying Y here the kernel will instrument some kernel code to | |
464 | extract some entropy from both original and artificially created | |
465 | program state. This will help especially embedded systems where | |
466 | there is little 'natural' source of entropy normally. The cost | |
467 | is some slowdown of the boot process (about 0.5%) and fork and | |
468 | irq processing. | |
469 | ||
470 | Note that entropy extracted this way is not cryptographically | |
471 | secure! | |
472 | ||
473 | This plugin was ported from grsecurity/PaX. More information at: | |
474 | * https://grsecurity.net/ | |
475 | * https://pax.grsecurity.net/ | |
476 | ||
c61f13ea KC |
477 | config GCC_PLUGIN_STRUCTLEAK |
478 | bool "Force initialization of variables containing userspace addresses" | |
479 | depends on GCC_PLUGINS | |
c9cf87ea DV |
480 | # Currently STRUCTLEAK inserts initialization out of live scope of |
481 | # variables from KASAN point of view. This leads to KASAN false | |
482 | # positive reports. Prohibit this combination for now. | |
483 | depends on !KASAN_EXTRA | |
c61f13ea | 484 | help |
f136e090 | 485 | This plugin zero-initializes any structures containing a |
c61f13ea KC |
486 | __user attribute. This can prevent some classes of information |
487 | exposures. | |
488 | ||
489 | This plugin was ported from grsecurity/PaX. More information at: | |
490 | * https://grsecurity.net/ | |
491 | * https://pax.grsecurity.net/ | |
492 | ||
f7dd2507 AB |
493 | config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL |
494 | bool "Force initialize all struct type variables passed by reference" | |
495 | depends on GCC_PLUGIN_STRUCTLEAK | |
caa91ba5 | 496 | depends on !COMPILE_TEST |
f7dd2507 AB |
497 | help |
498 | Zero initialize any struct type local variable that may be passed by | |
499 | reference without having been initialized. | |
500 | ||
c61f13ea KC |
501 | config GCC_PLUGIN_STRUCTLEAK_VERBOSE |
502 | bool "Report forcefully initialized variables" | |
503 | depends on GCC_PLUGIN_STRUCTLEAK | |
1658dcee | 504 | depends on !COMPILE_TEST # too noisy |
c61f13ea KC |
505 | help |
506 | This option will cause a warning to be printed each time the | |
507 | structleak plugin finds a variable it thinks needs to be | |
508 | initialized. Since not all existing initializers are detected | |
509 | by the plugin, this can produce false positive warnings. | |
510 | ||
313dd1b6 KC |
511 | config GCC_PLUGIN_RANDSTRUCT |
512 | bool "Randomize layout of sensitive kernel structures" | |
513 | depends on GCC_PLUGINS | |
514 | select MODVERSIONS if MODULES | |
515 | help | |
9225331b KC |
516 | If you say Y here, the layouts of structures that are entirely |
517 | function pointers (and have not been manually annotated with | |
518 | __no_randomize_layout), or structures that have been explicitly | |
519 | marked with __randomize_layout, will be randomized at compile-time. | |
520 | This can introduce the requirement of an additional information | |
521 | exposure vulnerability for exploits targeting these structure | |
522 | types. | |
313dd1b6 KC |
523 | |
524 | Enabling this feature will introduce some performance impact, | |
525 | slightly increase memory usage, and prevent the use of forensic | |
526 | tools like Volatility against the system (unless the kernel | |
527 | source tree isn't cleaned after kernel installation). | |
528 | ||
529 | The seed used for compilation is located at | |
530 | scripts/gcc-plgins/randomize_layout_seed.h. It remains after | |
531 | a make clean to allow for external modules to be compiled with | |
532 | the existing seed and will be removed by a make mrproper or | |
533 | make distclean. | |
534 | ||
535 | Note that the implementation requires gcc 4.7 or newer. | |
536 | ||
537 | This plugin was ported from grsecurity/PaX. More information at: | |
538 | * https://grsecurity.net/ | |
539 | * https://pax.grsecurity.net/ | |
540 | ||
541 | config GCC_PLUGIN_RANDSTRUCT_PERFORMANCE | |
542 | bool "Use cacheline-aware structure randomization" | |
543 | depends on GCC_PLUGIN_RANDSTRUCT | |
1658dcee | 544 | depends on !COMPILE_TEST # do not reduce test coverage |
313dd1b6 KC |
545 | help |
546 | If you say Y here, the RANDSTRUCT randomization will make a | |
547 | best effort at restricting randomization to cacheline-sized | |
548 | groups of elements. It will further not randomize bitfields | |
549 | in structures. This reduces the performance hit of RANDSTRUCT | |
550 | at the cost of weakened randomization. | |
551 | ||
d148eac0 | 552 | config HAVE_STACKPROTECTOR |
19952a92 KC |
553 | bool |
554 | help | |
555 | An arch should select this symbol if: | |
19952a92 KC |
556 | - it has implemented a stack canary (e.g. __stack_chk_guard) |
557 | ||
2a61f474 MY |
558 | config CC_HAS_STACKPROTECTOR_NONE |
559 | def_bool $(cc-option,-fno-stack-protector) | |
560 | ||
050e9baa | 561 | config STACKPROTECTOR |
2a61f474 | 562 | bool "Stack Protector buffer overflow detection" |
d148eac0 | 563 | depends on HAVE_STACKPROTECTOR |
2a61f474 MY |
564 | depends on $(cc-option,-fstack-protector) |
565 | default y | |
19952a92 | 566 | help |
8779657d | 567 | This option turns on the "stack-protector" GCC feature. This |
19952a92 KC |
568 | feature puts, at the beginning of functions, a canary value on |
569 | the stack just before the return address, and validates | |
570 | the value just before actually returning. Stack based buffer | |
571 | overflows (that need to overwrite this return address) now also | |
572 | overwrite the canary, which gets detected and the attack is then | |
573 | neutralized via a kernel panic. | |
574 | ||
8779657d KC |
575 | Functions will have the stack-protector canary logic added if they |
576 | have an 8-byte or larger character array on the stack. | |
577 | ||
19952a92 | 578 | This feature requires gcc version 4.2 or above, or a distribution |
8779657d KC |
579 | gcc with the feature backported ("-fstack-protector"). |
580 | ||
581 | On an x86 "defconfig" build, this feature adds canary checks to | |
582 | about 3% of all kernel functions, which increases kernel code size | |
583 | by about 0.3%. | |
584 | ||
050e9baa | 585 | config STACKPROTECTOR_STRONG |
2a61f474 | 586 | bool "Strong Stack Protector" |
050e9baa | 587 | depends on STACKPROTECTOR |
2a61f474 MY |
588 | depends on $(cc-option,-fstack-protector-strong) |
589 | default y | |
8779657d KC |
590 | help |
591 | Functions will have the stack-protector canary logic added in any | |
592 | of the following conditions: | |
593 | ||
594 | - local variable's address used as part of the right hand side of an | |
595 | assignment or function argument | |
596 | - local variable is an array (or union containing an array), | |
597 | regardless of array type or length | |
598 | - uses register local variables | |
599 | ||
600 | This feature requires gcc version 4.9 or above, or a distribution | |
601 | gcc with the feature backported ("-fstack-protector-strong"). | |
602 | ||
603 | On an x86 "defconfig" build, this feature adds canary checks to | |
604 | about 20% of all kernel functions, which increases the kernel code | |
605 | size by about 2%. | |
606 | ||
0f60a8ef KC |
607 | config HAVE_ARCH_WITHIN_STACK_FRAMES |
608 | bool | |
609 | help | |
610 | An architecture should select this if it can walk the kernel stack | |
611 | frames to determine if an object is part of either the arguments | |
612 | or local variables (i.e. that it excludes saved return addresses, | |
613 | and similar) by implementing an inline arch_within_stack_frames(), | |
614 | which is used by CONFIG_HARDENED_USERCOPY. | |
615 | ||
91d1aa43 | 616 | config HAVE_CONTEXT_TRACKING |
2b1d5024 FW |
617 | bool |
618 | help | |
91d1aa43 FW |
619 | Provide kernel/user boundaries probes necessary for subsystems |
620 | that need it, such as userspace RCU extended quiescent state. | |
621 | Syscalls need to be wrapped inside user_exit()-user_enter() through | |
622 | the slow path using TIF_NOHZ flag. Exceptions handlers must be | |
623 | wrapped as well. Irqs are already protected inside | |
624 | rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on | |
625 | irq exit still need to be protected. | |
2b1d5024 | 626 | |
b952741c FW |
627 | config HAVE_VIRT_CPU_ACCOUNTING |
628 | bool | |
629 | ||
40565b5a SG |
630 | config ARCH_HAS_SCALED_CPUTIME |
631 | bool | |
632 | ||
554b0004 KH |
633 | config HAVE_VIRT_CPU_ACCOUNTING_GEN |
634 | bool | |
635 | default y if 64BIT | |
636 | help | |
637 | With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. | |
638 | Before enabling this option, arch code must be audited | |
639 | to ensure there are no races in concurrent read/write of | |
640 | cputime_t. For example, reading/writing 64-bit cputime_t on | |
641 | some 32-bit arches may require multiple accesses, so proper | |
642 | locking is needed to protect against concurrent accesses. | |
643 | ||
644 | ||
fdf9c356 FW |
645 | config HAVE_IRQ_TIME_ACCOUNTING |
646 | bool | |
647 | help | |
648 | Archs need to ensure they use a high enough resolution clock to | |
649 | support irq time accounting and then call enable_sched_clock_irqtime(). | |
650 | ||
15626062 GS |
651 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE |
652 | bool | |
653 | ||
a00cc7d9 MW |
654 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
655 | bool | |
656 | ||
0ddab1d2 TK |
657 | config HAVE_ARCH_HUGE_VMAP |
658 | bool | |
659 | ||
0f8975ec PE |
660 | config HAVE_ARCH_SOFT_DIRTY |
661 | bool | |
662 | ||
786d35d4 DH |
663 | config HAVE_MOD_ARCH_SPECIFIC |
664 | bool | |
665 | help | |
666 | The arch uses struct mod_arch_specific to store data. Many arches | |
667 | just need a simple module loader without arch specific data - those | |
668 | should not enable this. | |
669 | ||
670 | config MODULES_USE_ELF_RELA | |
671 | bool | |
672 | help | |
673 | Modules only use ELF RELA relocations. Modules with ELF REL | |
674 | relocations will give an error. | |
675 | ||
676 | config MODULES_USE_ELF_REL | |
677 | bool | |
678 | help | |
679 | Modules only use ELF REL relocations. Modules with ELF RELA | |
680 | relocations will give an error. | |
681 | ||
cc1f0274 FW |
682 | config HAVE_IRQ_EXIT_ON_IRQ_STACK |
683 | bool | |
684 | help | |
685 | Architecture doesn't only execute the irq handler on the irq stack | |
686 | but also irq_exit(). This way we can process softirqs on this irq | |
687 | stack instead of switching to a new one when we call __do_softirq() | |
688 | in the end of an hardirq. | |
689 | This spares a stack switch and improves cache usage on softirq | |
690 | processing. | |
691 | ||
235a8f02 KS |
692 | config PGTABLE_LEVELS |
693 | int | |
694 | default 2 | |
695 | ||
2b68f6ca KC |
696 | config ARCH_HAS_ELF_RANDOMIZE |
697 | bool | |
698 | help | |
699 | An architecture supports choosing randomized locations for | |
700 | stack, mmap, brk, and ET_DYN. Defined functions: | |
701 | - arch_mmap_rnd() | |
204db6ed | 702 | - arch_randomize_brk() |
2b68f6ca | 703 | |
d07e2259 DC |
704 | config HAVE_ARCH_MMAP_RND_BITS |
705 | bool | |
706 | help | |
707 | An arch should select this symbol if it supports setting a variable | |
708 | number of bits for use in establishing the base address for mmap | |
709 | allocations, has MMU enabled and provides values for both: | |
710 | - ARCH_MMAP_RND_BITS_MIN | |
711 | - ARCH_MMAP_RND_BITS_MAX | |
712 | ||
5f56a5df JS |
713 | config HAVE_EXIT_THREAD |
714 | bool | |
715 | help | |
716 | An architecture implements exit_thread. | |
717 | ||
d07e2259 DC |
718 | config ARCH_MMAP_RND_BITS_MIN |
719 | int | |
720 | ||
721 | config ARCH_MMAP_RND_BITS_MAX | |
722 | int | |
723 | ||
724 | config ARCH_MMAP_RND_BITS_DEFAULT | |
725 | int | |
726 | ||
727 | config ARCH_MMAP_RND_BITS | |
728 | int "Number of bits to use for ASLR of mmap base address" if EXPERT | |
729 | range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX | |
730 | default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT | |
731 | default ARCH_MMAP_RND_BITS_MIN | |
732 | depends on HAVE_ARCH_MMAP_RND_BITS | |
733 | help | |
734 | This value can be used to select the number of bits to use to | |
735 | determine the random offset to the base address of vma regions | |
736 | resulting from mmap allocations. This value will be bounded | |
737 | by the architecture's minimum and maximum supported values. | |
738 | ||
739 | This value can be changed after boot using the | |
740 | /proc/sys/vm/mmap_rnd_bits tunable | |
741 | ||
742 | config HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
743 | bool | |
744 | help | |
745 | An arch should select this symbol if it supports running applications | |
746 | in compatibility mode, supports setting a variable number of bits for | |
747 | use in establishing the base address for mmap allocations, has MMU | |
748 | enabled and provides values for both: | |
749 | - ARCH_MMAP_RND_COMPAT_BITS_MIN | |
750 | - ARCH_MMAP_RND_COMPAT_BITS_MAX | |
751 | ||
752 | config ARCH_MMAP_RND_COMPAT_BITS_MIN | |
753 | int | |
754 | ||
755 | config ARCH_MMAP_RND_COMPAT_BITS_MAX | |
756 | int | |
757 | ||
758 | config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
759 | int | |
760 | ||
761 | config ARCH_MMAP_RND_COMPAT_BITS | |
762 | int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT | |
763 | range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX | |
764 | default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
765 | default ARCH_MMAP_RND_COMPAT_BITS_MIN | |
766 | depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
767 | help | |
768 | This value can be used to select the number of bits to use to | |
769 | determine the random offset to the base address of vma regions | |
770 | resulting from mmap allocations for compatible applications This | |
771 | value will be bounded by the architecture's minimum and maximum | |
772 | supported values. | |
773 | ||
774 | This value can be changed after boot using the | |
775 | /proc/sys/vm/mmap_rnd_compat_bits tunable | |
776 | ||
1b028f78 DS |
777 | config HAVE_ARCH_COMPAT_MMAP_BASES |
778 | bool | |
779 | help | |
780 | This allows 64bit applications to invoke 32-bit mmap() syscall | |
781 | and vice-versa 32-bit applications to call 64-bit mmap(). | |
782 | Required for applications doing different bitness syscalls. | |
783 | ||
3033f14a JT |
784 | config HAVE_COPY_THREAD_TLS |
785 | bool | |
786 | help | |
787 | Architecture provides copy_thread_tls to accept tls argument via | |
788 | normal C parameter passing, rather than extracting the syscall | |
789 | argument from pt_regs. | |
790 | ||
b9ab5ebb JP |
791 | config HAVE_STACK_VALIDATION |
792 | bool | |
793 | help | |
794 | Architecture supports the 'objtool check' host tool command, which | |
795 | performs compile-time stack metadata validation. | |
796 | ||
af085d90 JP |
797 | config HAVE_RELIABLE_STACKTRACE |
798 | bool | |
799 | help | |
800 | Architecture has a save_stack_trace_tsk_reliable() function which | |
801 | only returns a stack trace if it can guarantee the trace is reliable. | |
802 | ||
468a9428 GS |
803 | config HAVE_ARCH_HASH |
804 | bool | |
805 | default n | |
806 | help | |
807 | If this is set, the architecture provides an <asm/hash.h> | |
808 | file which provides platform-specific implementations of some | |
809 | functions in <linux/hash.h> or fs/namei.c. | |
810 | ||
3a495511 WBG |
811 | config ISA_BUS_API |
812 | def_bool ISA | |
813 | ||
d2125043 AV |
814 | # |
815 | # ABI hall of shame | |
816 | # | |
817 | config CLONE_BACKWARDS | |
818 | bool | |
819 | help | |
820 | Architecture has tls passed as the 4th argument of clone(2), | |
821 | not the 5th one. | |
822 | ||
823 | config CLONE_BACKWARDS2 | |
824 | bool | |
825 | help | |
826 | Architecture has the first two arguments of clone(2) swapped. | |
827 | ||
dfa9771a MS |
828 | config CLONE_BACKWARDS3 |
829 | bool | |
830 | help | |
831 | Architecture has tls passed as the 3rd argument of clone(2), | |
832 | not the 5th one. | |
833 | ||
eaca6eae AV |
834 | config ODD_RT_SIGACTION |
835 | bool | |
836 | help | |
837 | Architecture has unusual rt_sigaction(2) arguments | |
838 | ||
0a0e8cdf AV |
839 | config OLD_SIGSUSPEND |
840 | bool | |
841 | help | |
842 | Architecture has old sigsuspend(2) syscall, of one-argument variety | |
843 | ||
844 | config OLD_SIGSUSPEND3 | |
845 | bool | |
846 | help | |
847 | Even weirder antique ABI - three-argument sigsuspend(2) | |
848 | ||
495dfbf7 AV |
849 | config OLD_SIGACTION |
850 | bool | |
851 | help | |
852 | Architecture has old sigaction(2) syscall. Nope, not the same | |
853 | as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), | |
854 | but fairly different variant of sigaction(2), thanks to OSF/1 | |
855 | compatibility... | |
856 | ||
857 | config COMPAT_OLD_SIGACTION | |
858 | bool | |
859 | ||
d4703dda DD |
860 | config 64BIT_TIME |
861 | def_bool ARCH_HAS_64BIT_TIME | |
862 | help | |
863 | This should be selected by all architectures that need to support | |
864 | new system calls with a 64-bit time_t. This is relevant on all 32-bit | |
865 | architectures, and 64-bit architectures as part of compat syscall | |
866 | handling. | |
867 | ||
17435e5f DD |
868 | config COMPAT_32BIT_TIME |
869 | def_bool (!64BIT && 64BIT_TIME) || COMPAT | |
870 | help | |
871 | This enables 32 bit time_t support in addition to 64 bit time_t support. | |
872 | This is relevant on all 32-bit architectures, and 64-bit architectures | |
873 | as part of compat syscall handling. | |
874 | ||
0d4a619b CH |
875 | config ARCH_NO_COHERENT_DMA_MMAP |
876 | bool | |
877 | ||
fff7fb0b ZZ |
878 | config CPU_NO_EFFICIENT_FFS |
879 | def_bool n | |
880 | ||
ba14a194 AL |
881 | config HAVE_ARCH_VMAP_STACK |
882 | def_bool n | |
883 | help | |
884 | An arch should select this symbol if it can support kernel stacks | |
885 | in vmalloc space. This means: | |
886 | ||
887 | - vmalloc space must be large enough to hold many kernel stacks. | |
888 | This may rule out many 32-bit architectures. | |
889 | ||
890 | - Stacks in vmalloc space need to work reliably. For example, if | |
891 | vmap page tables are created on demand, either this mechanism | |
892 | needs to work while the stack points to a virtual address with | |
893 | unpopulated page tables or arch code (switch_to() and switch_mm(), | |
894 | most likely) needs to ensure that the stack's page table entries | |
895 | are populated before running on a possibly unpopulated stack. | |
896 | ||
897 | - If the stack overflows into a guard page, something reasonable | |
898 | should happen. The definition of "reasonable" is flexible, but | |
899 | instantly rebooting without logging anything would be unfriendly. | |
900 | ||
901 | config VMAP_STACK | |
902 | default y | |
903 | bool "Use a virtually-mapped stack" | |
904 | depends on HAVE_ARCH_VMAP_STACK && !KASAN | |
905 | ---help--- | |
906 | Enable this if you want the use virtually-mapped kernel stacks | |
907 | with guard pages. This causes kernel stack overflows to be | |
908 | caught immediately rather than causing difficult-to-diagnose | |
909 | corruption. | |
910 | ||
911 | This is presently incompatible with KASAN because KASAN expects | |
912 | the stack to map directly to the KASAN shadow map using a formula | |
913 | that is incorrect if the stack is in vmalloc space. | |
914 | ||
ad21fc4f LA |
915 | config ARCH_OPTIONAL_KERNEL_RWX |
916 | def_bool n | |
917 | ||
918 | config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
919 | def_bool n | |
920 | ||
921 | config ARCH_HAS_STRICT_KERNEL_RWX | |
922 | def_bool n | |
923 | ||
0f5bf6d0 | 924 | config STRICT_KERNEL_RWX |
ad21fc4f LA |
925 | bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX |
926 | depends on ARCH_HAS_STRICT_KERNEL_RWX | |
927 | default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
928 | help | |
929 | If this is set, kernel text and rodata memory will be made read-only, | |
930 | and non-text memory will be made non-executable. This provides | |
931 | protection against certain security exploits (e.g. executing the heap | |
932 | or modifying text) | |
933 | ||
934 | These features are considered standard security practice these days. | |
935 | You should say Y here in almost all cases. | |
936 | ||
937 | config ARCH_HAS_STRICT_MODULE_RWX | |
938 | def_bool n | |
939 | ||
0f5bf6d0 | 940 | config STRICT_MODULE_RWX |
ad21fc4f LA |
941 | bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX |
942 | depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES | |
943 | default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
944 | help | |
945 | If this is set, module text and rodata memory will be made read-only, | |
946 | and non-text memory will be made non-executable. This provides | |
947 | protection against certain security exploits (e.g. writing to text) | |
948 | ||
ea8c64ac CH |
949 | # select if the architecture provides an asm/dma-direct.h header |
950 | config ARCH_HAS_PHYS_TO_DMA | |
951 | bool | |
952 | ||
7a46ec0e KC |
953 | config ARCH_HAS_REFCOUNT |
954 | bool | |
955 | help | |
956 | An architecture selects this when it has implemented refcount_t | |
957 | using open coded assembly primitives that provide an optimized | |
958 | refcount_t implementation, possibly at the expense of some full | |
959 | refcount state checks of CONFIG_REFCOUNT_FULL=y. | |
960 | ||
961 | The refcount overflow check behavior, however, must be retained. | |
962 | Catching overflows is the primary security concern for protecting | |
963 | against bugs in reference counts. | |
964 | ||
fd25d19f KC |
965 | config REFCOUNT_FULL |
966 | bool "Perform full reference count validation at the expense of speed" | |
967 | help | |
968 | Enabling this switches the refcounting infrastructure from a fast | |
969 | unchecked atomic_t implementation to a fully state checked | |
970 | implementation, which can be (slightly) slower but provides protections | |
971 | against various use-after-free conditions that can be used in | |
972 | security flaw exploits. | |
973 | ||
2521f2c2 | 974 | source "kernel/gcov/Kconfig" |