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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 | ||
692f66f2 HB |
12 | config CRASH_CORE |
13 | bool | |
14 | ||
2965faa5 | 15 | config KEXEC_CORE |
692f66f2 | 16 | select CRASH_CORE |
2965faa5 DY |
17 | bool |
18 | ||
467d2782 TJB |
19 | config HAVE_IMA_KEXEC |
20 | bool | |
21 | ||
125e5645 | 22 | config OPROFILE |
b309a294 | 23 | tristate "OProfile system profiling" |
125e5645 MD |
24 | depends on PROFILING |
25 | depends on HAVE_OPROFILE | |
d69d59f4 | 26 | select RING_BUFFER |
9a5963eb | 27 | select RING_BUFFER_ALLOW_SWAP |
125e5645 MD |
28 | help |
29 | OProfile is a profiling system capable of profiling the | |
30 | whole system, include the kernel, kernel modules, libraries, | |
31 | and applications. | |
32 | ||
33 | If unsure, say N. | |
34 | ||
4d4036e0 JY |
35 | config OPROFILE_EVENT_MULTIPLEX |
36 | bool "OProfile multiplexing support (EXPERIMENTAL)" | |
37 | default n | |
38 | depends on OPROFILE && X86 | |
39 | help | |
40 | The number of hardware counters is limited. The multiplexing | |
41 | feature enables OProfile to gather more events than counters | |
42 | are provided by the hardware. This is realized by switching | |
9332ef9d | 43 | between events at a user specified time interval. |
4d4036e0 JY |
44 | |
45 | If unsure, say N. | |
46 | ||
125e5645 | 47 | config HAVE_OPROFILE |
9ba16087 | 48 | bool |
125e5645 | 49 | |
dcfce4a0 RR |
50 | config OPROFILE_NMI_TIMER |
51 | def_bool y | |
af9feebe | 52 | depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64 |
dcfce4a0 | 53 | |
125e5645 MD |
54 | config KPROBES |
55 | bool "Kprobes" | |
05ed160e | 56 | depends on MODULES |
125e5645 | 57 | depends on HAVE_KPROBES |
05ed160e | 58 | select KALLSYMS |
125e5645 MD |
59 | help |
60 | Kprobes allows you to trap at almost any kernel address and | |
61 | execute a callback function. register_kprobe() establishes | |
62 | a probepoint and specifies the callback. Kprobes is useful | |
63 | for kernel debugging, non-intrusive instrumentation and testing. | |
64 | If in doubt, say "N". | |
65 | ||
45f81b1c | 66 | config JUMP_LABEL |
c5905afb | 67 | bool "Optimize very unlikely/likely branches" |
45f81b1c SR |
68 | depends on HAVE_ARCH_JUMP_LABEL |
69 | help | |
c5905afb IM |
70 | This option enables a transparent branch optimization that |
71 | makes certain almost-always-true or almost-always-false branch | |
72 | conditions even cheaper to execute within the kernel. | |
73 | ||
74 | Certain performance-sensitive kernel code, such as trace points, | |
75 | scheduler functionality, networking code and KVM have such | |
76 | branches and include support for this optimization technique. | |
77 | ||
45f81b1c | 78 | If it is detected that the compiler has support for "asm goto", |
c5905afb IM |
79 | the kernel will compile such branches with just a nop |
80 | instruction. When the condition flag is toggled to true, the | |
81 | nop will be converted to a jump instruction to execute the | |
82 | conditional block of instructions. | |
83 | ||
84 | This technique lowers overhead and stress on the branch prediction | |
85 | of the processor and generally makes the kernel faster. The update | |
86 | of the condition is slower, but those are always very rare. | |
45f81b1c | 87 | |
c5905afb IM |
88 | ( On 32-bit x86, the necessary options added to the compiler |
89 | flags may increase the size of the kernel slightly. ) | |
45f81b1c | 90 | |
1987c947 PZ |
91 | config STATIC_KEYS_SELFTEST |
92 | bool "Static key selftest" | |
93 | depends on JUMP_LABEL | |
94 | help | |
95 | Boot time self-test of the branch patching code. | |
96 | ||
afd66255 | 97 | config OPTPROBES |
5cc718b9 MH |
98 | def_bool y |
99 | depends on KPROBES && HAVE_OPTPROBES | |
a30b85df | 100 | select TASKS_RCU if PREEMPT |
afd66255 | 101 | |
e7dbfe34 MH |
102 | config KPROBES_ON_FTRACE |
103 | def_bool y | |
104 | depends on KPROBES && HAVE_KPROBES_ON_FTRACE | |
105 | depends on DYNAMIC_FTRACE_WITH_REGS | |
106 | help | |
107 | If function tracer is enabled and the arch supports full | |
108 | passing of pt_regs to function tracing, then kprobes can | |
109 | optimize on top of function tracing. | |
110 | ||
2b144498 | 111 | config UPROBES |
09294e31 | 112 | def_bool n |
e8f4aa60 | 113 | depends on ARCH_SUPPORTS_UPROBES |
2b144498 | 114 | help |
7b2d81d4 IM |
115 | Uprobes is the user-space counterpart to kprobes: they |
116 | enable instrumentation applications (such as 'perf probe') | |
117 | to establish unintrusive probes in user-space binaries and | |
118 | libraries, by executing handler functions when the probes | |
119 | are hit by user-space applications. | |
120 | ||
121 | ( These probes come in the form of single-byte breakpoints, | |
122 | managed by the kernel and kept transparent to the probed | |
123 | application. ) | |
2b144498 | 124 | |
c19fa94a JH |
125 | config HAVE_64BIT_ALIGNED_ACCESS |
126 | def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS | |
127 | help | |
128 | Some architectures require 64 bit accesses to be 64 bit | |
129 | aligned, which also requires structs containing 64 bit values | |
130 | to be 64 bit aligned too. This includes some 32 bit | |
131 | architectures which can do 64 bit accesses, as well as 64 bit | |
132 | architectures without unaligned access. | |
133 | ||
134 | This symbol should be selected by an architecture if 64 bit | |
135 | accesses are required to be 64 bit aligned in this way even | |
136 | though it is not a 64 bit architecture. | |
137 | ||
138 | See Documentation/unaligned-memory-access.txt for more | |
139 | information on the topic of unaligned memory accesses. | |
140 | ||
58340a07 | 141 | config HAVE_EFFICIENT_UNALIGNED_ACCESS |
9ba16087 | 142 | bool |
58340a07 JB |
143 | help |
144 | Some architectures are unable to perform unaligned accesses | |
145 | without the use of get_unaligned/put_unaligned. Others are | |
146 | unable to perform such accesses efficiently (e.g. trap on | |
147 | unaligned access and require fixing it up in the exception | |
148 | handler.) | |
149 | ||
150 | This symbol should be selected by an architecture if it can | |
151 | perform unaligned accesses efficiently to allow different | |
152 | code paths to be selected for these cases. Some network | |
153 | drivers, for example, could opt to not fix up alignment | |
154 | problems with received packets if doing so would not help | |
155 | much. | |
156 | ||
157 | See Documentation/unaligned-memory-access.txt for more | |
158 | information on the topic of unaligned memory accesses. | |
159 | ||
cf66bb93 DW |
160 | config ARCH_USE_BUILTIN_BSWAP |
161 | bool | |
162 | help | |
163 | Modern versions of GCC (since 4.4) have builtin functions | |
164 | for handling byte-swapping. Using these, instead of the old | |
165 | inline assembler that the architecture code provides in the | |
166 | __arch_bswapXX() macros, allows the compiler to see what's | |
167 | happening and offers more opportunity for optimisation. In | |
168 | particular, the compiler will be able to combine the byteswap | |
169 | with a nearby load or store and use load-and-swap or | |
170 | store-and-swap instructions if the architecture has them. It | |
171 | should almost *never* result in code which is worse than the | |
172 | hand-coded assembler in <asm/swab.h>. But just in case it | |
173 | does, the use of the builtins is optional. | |
174 | ||
175 | Any architecture with load-and-swap or store-and-swap | |
176 | instructions should set this. And it shouldn't hurt to set it | |
177 | on architectures that don't have such instructions. | |
178 | ||
9edddaa2 AM |
179 | config KRETPROBES |
180 | def_bool y | |
181 | depends on KPROBES && HAVE_KRETPROBES | |
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 | ||
540adea3 | 205 | config HAVE_FUNCTION_ERROR_INJECTION |
9802d865 JB |
206 | bool |
207 | ||
42a0bb3f PM |
208 | config HAVE_NMI |
209 | bool | |
210 | ||
1f5a4ad9 RM |
211 | # |
212 | # An arch should select this if it provides all these things: | |
213 | # | |
214 | # task_pt_regs() in asm/processor.h or asm/ptrace.h | |
215 | # arch_has_single_step() if there is hardware single-step support | |
216 | # arch_has_block_step() if there is hardware block-step support | |
1f5a4ad9 RM |
217 | # asm/syscall.h supplying asm-generic/syscall.h interface |
218 | # linux/regset.h user_regset interfaces | |
219 | # CORE_DUMP_USE_REGSET #define'd in linux/elf.h | |
220 | # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} | |
221 | # TIF_NOTIFY_RESUME calls tracehook_notify_resume() | |
222 | # signal delivery calls tracehook_signal_handler() | |
223 | # | |
224 | config HAVE_ARCH_TRACEHOOK | |
9ba16087 | 225 | bool |
1f5a4ad9 | 226 | |
c64be2bb MS |
227 | config HAVE_DMA_CONTIGUOUS |
228 | bool | |
229 | ||
29d5e047 TG |
230 | config GENERIC_SMP_IDLE_THREAD |
231 | bool | |
232 | ||
485cf5da KH |
233 | config GENERIC_IDLE_POLL_SETUP |
234 | bool | |
235 | ||
6974f0c4 DM |
236 | config ARCH_HAS_FORTIFY_SOURCE |
237 | bool | |
238 | help | |
239 | An architecture should select this when it can successfully | |
240 | build and run with CONFIG_FORTIFY_SOURCE. | |
241 | ||
d2852a22 DB |
242 | # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h |
243 | config ARCH_HAS_SET_MEMORY | |
244 | bool | |
245 | ||
0500871f DH |
246 | # Select if arch init_task must go in the __init_task_data section |
247 | config ARCH_TASK_STRUCT_ON_STACK | |
a4a2eb49 TG |
248 | bool |
249 | ||
f5e10287 TG |
250 | # Select if arch has its private alloc_task_struct() function |
251 | config ARCH_TASK_STRUCT_ALLOCATOR | |
252 | bool | |
253 | ||
5905429a KC |
254 | config HAVE_ARCH_THREAD_STRUCT_WHITELIST |
255 | bool | |
256 | depends on !ARCH_TASK_STRUCT_ALLOCATOR | |
257 | help | |
258 | An architecture should select this to provide hardened usercopy | |
259 | knowledge about what region of the thread_struct should be | |
260 | whitelisted for copying to userspace. Normally this is only the | |
261 | FPU registers. Specifically, arch_thread_struct_whitelist() | |
262 | should be implemented. Without this, the entire thread_struct | |
263 | field in task_struct will be left whitelisted. | |
264 | ||
b235beea LT |
265 | # Select if arch has its private alloc_thread_stack() function |
266 | config ARCH_THREAD_STACK_ALLOCATOR | |
f5e10287 TG |
267 | bool |
268 | ||
5aaeb5c0 IM |
269 | # Select if arch wants to size task_struct dynamically via arch_task_struct_size: |
270 | config ARCH_WANTS_DYNAMIC_TASK_STRUCT | |
271 | bool | |
272 | ||
f850c30c HC |
273 | config HAVE_REGS_AND_STACK_ACCESS_API |
274 | bool | |
e01292b1 HC |
275 | help |
276 | This symbol should be selected by an architecure if it supports | |
277 | the API needed to access registers and stack entries from pt_regs, | |
278 | declared in asm/ptrace.h | |
279 | For example the kprobes-based event tracer needs this API. | |
f850c30c | 280 | |
d7822b1e MD |
281 | config HAVE_RSEQ |
282 | bool | |
283 | depends on HAVE_REGS_AND_STACK_ACCESS_API | |
284 | help | |
285 | This symbol should be selected by an architecture if it | |
286 | supports an implementation of restartable sequences. | |
287 | ||
9483a578 | 288 | config HAVE_CLK |
9ba16087 | 289 | bool |
9483a578 DB |
290 | help |
291 | The <linux/clk.h> calls support software clock gating and | |
292 | thus are a key power management tool on many systems. | |
293 | ||
62a038d3 P |
294 | config HAVE_HW_BREAKPOINT |
295 | bool | |
99e8c5a3 | 296 | depends on PERF_EVENTS |
62a038d3 | 297 | |
0102752e FW |
298 | config HAVE_MIXED_BREAKPOINTS_REGS |
299 | bool | |
300 | depends on HAVE_HW_BREAKPOINT | |
301 | help | |
302 | Depending on the arch implementation of hardware breakpoints, | |
303 | some of them have separate registers for data and instruction | |
304 | breakpoints addresses, others have mixed registers to store | |
305 | them but define the access type in a control register. | |
306 | Select this option if your arch implements breakpoints under the | |
307 | latter fashion. | |
308 | ||
7c68af6e AK |
309 | config HAVE_USER_RETURN_NOTIFIER |
310 | bool | |
a1922ed6 | 311 | |
c01d4323 FW |
312 | config HAVE_PERF_EVENTS_NMI |
313 | bool | |
23637d47 FW |
314 | help |
315 | System hardware can generate an NMI using the perf event | |
316 | subsystem. Also has support for calculating CPU cycle events | |
317 | to determine how many clock cycles in a given period. | |
c01d4323 | 318 | |
05a4a952 NP |
319 | config HAVE_HARDLOCKUP_DETECTOR_PERF |
320 | bool | |
321 | depends on HAVE_PERF_EVENTS_NMI | |
322 | help | |
323 | The arch chooses to use the generic perf-NMI-based hardlockup | |
324 | detector. Must define HAVE_PERF_EVENTS_NMI. | |
325 | ||
326 | config HAVE_NMI_WATCHDOG | |
327 | depends on HAVE_NMI | |
328 | bool | |
329 | help | |
330 | The arch provides a low level NMI watchdog. It provides | |
331 | asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). | |
332 | ||
333 | config HAVE_HARDLOCKUP_DETECTOR_ARCH | |
334 | bool | |
335 | select HAVE_NMI_WATCHDOG | |
336 | help | |
337 | The arch chooses to provide its own hardlockup detector, which is | |
338 | a superset of the HAVE_NMI_WATCHDOG. It also conforms to config | |
339 | interfaces and parameters provided by hardlockup detector subsystem. | |
340 | ||
c5e63197 JO |
341 | config HAVE_PERF_REGS |
342 | bool | |
343 | help | |
344 | Support selective register dumps for perf events. This includes | |
345 | bit-mapping of each registers and a unique architecture id. | |
346 | ||
c5ebcedb JO |
347 | config HAVE_PERF_USER_STACK_DUMP |
348 | bool | |
349 | help | |
350 | Support user stack dumps for perf event samples. This needs | |
351 | access to the user stack pointer which is not unified across | |
352 | architectures. | |
353 | ||
bf5438fc JB |
354 | config HAVE_ARCH_JUMP_LABEL |
355 | bool | |
356 | ||
26723911 PZ |
357 | config HAVE_RCU_TABLE_FREE |
358 | bool | |
359 | ||
df013ffb HY |
360 | config ARCH_HAVE_NMI_SAFE_CMPXCHG |
361 | bool | |
362 | ||
43570fd2 HC |
363 | config HAVE_ALIGNED_STRUCT_PAGE |
364 | bool | |
365 | help | |
366 | This makes sure that struct pages are double word aligned and that | |
367 | e.g. the SLUB allocator can perform double word atomic operations | |
368 | on a struct page for better performance. However selecting this | |
369 | might increase the size of a struct page by a word. | |
370 | ||
4156153c HC |
371 | config HAVE_CMPXCHG_LOCAL |
372 | bool | |
373 | ||
2565409f HC |
374 | config HAVE_CMPXCHG_DOUBLE |
375 | bool | |
376 | ||
77e58496 PM |
377 | config ARCH_WEAK_RELEASE_ACQUIRE |
378 | bool | |
379 | ||
c1d7e01d WD |
380 | config ARCH_WANT_IPC_PARSE_VERSION |
381 | bool | |
382 | ||
383 | config ARCH_WANT_COMPAT_IPC_PARSE_VERSION | |
384 | bool | |
385 | ||
48b25c43 | 386 | config ARCH_WANT_OLD_COMPAT_IPC |
c1d7e01d | 387 | select ARCH_WANT_COMPAT_IPC_PARSE_VERSION |
48b25c43 CM |
388 | bool |
389 | ||
e2cfabdf WD |
390 | config HAVE_ARCH_SECCOMP_FILTER |
391 | bool | |
392 | help | |
fb0fadf9 | 393 | An arch should select this symbol if it provides all of these things: |
bb6ea430 WD |
394 | - syscall_get_arch() |
395 | - syscall_get_arguments() | |
396 | - syscall_rollback() | |
397 | - syscall_set_return_value() | |
fb0fadf9 WD |
398 | - SIGSYS siginfo_t support |
399 | - secure_computing is called from a ptrace_event()-safe context | |
400 | - secure_computing return value is checked and a return value of -1 | |
401 | results in the system call being skipped immediately. | |
48dc92b9 | 402 | - seccomp syscall wired up |
e2cfabdf WD |
403 | |
404 | config SECCOMP_FILTER | |
405 | def_bool y | |
406 | depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET | |
407 | help | |
408 | Enable tasks to build secure computing environments defined | |
409 | in terms of Berkeley Packet Filter programs which implement | |
410 | task-defined system call filtering polices. | |
411 | ||
5fb94e9c | 412 | See Documentation/userspace-api/seccomp_filter.rst for details. |
e2cfabdf | 413 | |
59f53855 MY |
414 | preferred-plugin-hostcc := $(if-success,[ $(gcc-version) -ge 40800 ],$(HOSTCXX),$(HOSTCC)) |
415 | ||
416 | config PLUGIN_HOSTCC | |
417 | string | |
418 | default "$(shell,$(srctree)/scripts/gcc-plugin.sh "$(preferred-plugin-hostcc)" "$(HOSTCXX)" "$(CC)")" | |
419 | help | |
420 | Host compiler used to build GCC plugins. This can be $(HOSTCXX), | |
421 | $(HOSTCC), or a null string if GCC plugin is unsupported. | |
422 | ||
6b90bd4b ER |
423 | config HAVE_GCC_PLUGINS |
424 | bool | |
425 | help | |
426 | An arch should select this symbol if it supports building with | |
427 | GCC plugins. | |
428 | ||
429 | menuconfig GCC_PLUGINS | |
430 | bool "GCC plugins" | |
431 | depends on HAVE_GCC_PLUGINS | |
59f53855 | 432 | depends on PLUGIN_HOSTCC != "" |
6b90bd4b ER |
433 | help |
434 | GCC plugins are loadable modules that provide extra features to the | |
435 | compiler. They are useful for runtime instrumentation and static analysis. | |
436 | ||
437 | See Documentation/gcc-plugins.txt for details. | |
438 | ||
0dae776c | 439 | config GCC_PLUGIN_CYC_COMPLEXITY |
215e2aa6 | 440 | bool "Compute the cyclomatic complexity of a function" if EXPERT |
0dae776c | 441 | depends on GCC_PLUGINS |
1658dcee | 442 | depends on !COMPILE_TEST # too noisy |
0dae776c ER |
443 | help |
444 | The complexity M of a function's control flow graph is defined as: | |
445 | M = E - N + 2P | |
446 | where | |
447 | ||
448 | E = the number of edges | |
449 | N = the number of nodes | |
450 | P = the number of connected components (exit nodes). | |
451 | ||
215e2aa6 KC |
452 | Enabling this plugin reports the complexity to stderr during the |
453 | build. It mainly serves as a simple example of how to create a | |
454 | gcc plugin for the kernel. | |
455 | ||
543c37cb ER |
456 | config GCC_PLUGIN_SANCOV |
457 | bool | |
458 | depends on GCC_PLUGINS | |
459 | help | |
460 | This plugin inserts a __sanitizer_cov_trace_pc() call at the start of | |
461 | basic blocks. It supports all gcc versions with plugin support (from | |
462 | gcc-4.5 on). It is based on the commit "Add fuzzing coverage support" | |
463 | by Dmitry Vyukov <dvyukov@google.com>. | |
464 | ||
38addce8 ER |
465 | config GCC_PLUGIN_LATENT_ENTROPY |
466 | bool "Generate some entropy during boot and runtime" | |
467 | depends on GCC_PLUGINS | |
468 | help | |
469 | By saying Y here the kernel will instrument some kernel code to | |
470 | extract some entropy from both original and artificially created | |
471 | program state. This will help especially embedded systems where | |
472 | there is little 'natural' source of entropy normally. The cost | |
473 | is some slowdown of the boot process (about 0.5%) and fork and | |
474 | irq processing. | |
475 | ||
476 | Note that entropy extracted this way is not cryptographically | |
477 | secure! | |
478 | ||
479 | This plugin was ported from grsecurity/PaX. More information at: | |
480 | * https://grsecurity.net/ | |
481 | * https://pax.grsecurity.net/ | |
482 | ||
c61f13ea KC |
483 | config GCC_PLUGIN_STRUCTLEAK |
484 | bool "Force initialization of variables containing userspace addresses" | |
485 | depends on GCC_PLUGINS | |
c9cf87ea DV |
486 | # Currently STRUCTLEAK inserts initialization out of live scope of |
487 | # variables from KASAN point of view. This leads to KASAN false | |
488 | # positive reports. Prohibit this combination for now. | |
489 | depends on !KASAN_EXTRA | |
c61f13ea | 490 | help |
f136e090 | 491 | This plugin zero-initializes any structures containing a |
c61f13ea KC |
492 | __user attribute. This can prevent some classes of information |
493 | exposures. | |
494 | ||
495 | This plugin was ported from grsecurity/PaX. More information at: | |
496 | * https://grsecurity.net/ | |
497 | * https://pax.grsecurity.net/ | |
498 | ||
f7dd2507 AB |
499 | config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL |
500 | bool "Force initialize all struct type variables passed by reference" | |
501 | depends on GCC_PLUGIN_STRUCTLEAK | |
caa91ba5 | 502 | depends on !COMPILE_TEST |
f7dd2507 AB |
503 | help |
504 | Zero initialize any struct type local variable that may be passed by | |
505 | reference without having been initialized. | |
506 | ||
c61f13ea KC |
507 | config GCC_PLUGIN_STRUCTLEAK_VERBOSE |
508 | bool "Report forcefully initialized variables" | |
509 | depends on GCC_PLUGIN_STRUCTLEAK | |
1658dcee | 510 | depends on !COMPILE_TEST # too noisy |
c61f13ea KC |
511 | help |
512 | This option will cause a warning to be printed each time the | |
513 | structleak plugin finds a variable it thinks needs to be | |
514 | initialized. Since not all existing initializers are detected | |
515 | by the plugin, this can produce false positive warnings. | |
516 | ||
313dd1b6 KC |
517 | config GCC_PLUGIN_RANDSTRUCT |
518 | bool "Randomize layout of sensitive kernel structures" | |
519 | depends on GCC_PLUGINS | |
520 | select MODVERSIONS if MODULES | |
521 | help | |
9225331b KC |
522 | If you say Y here, the layouts of structures that are entirely |
523 | function pointers (and have not been manually annotated with | |
524 | __no_randomize_layout), or structures that have been explicitly | |
525 | marked with __randomize_layout, will be randomized at compile-time. | |
526 | This can introduce the requirement of an additional information | |
527 | exposure vulnerability for exploits targeting these structure | |
528 | types. | |
313dd1b6 KC |
529 | |
530 | Enabling this feature will introduce some performance impact, | |
531 | slightly increase memory usage, and prevent the use of forensic | |
532 | tools like Volatility against the system (unless the kernel | |
533 | source tree isn't cleaned after kernel installation). | |
534 | ||
535 | The seed used for compilation is located at | |
536 | scripts/gcc-plgins/randomize_layout_seed.h. It remains after | |
537 | a make clean to allow for external modules to be compiled with | |
538 | the existing seed and will be removed by a make mrproper or | |
539 | make distclean. | |
540 | ||
541 | Note that the implementation requires gcc 4.7 or newer. | |
542 | ||
543 | This plugin was ported from grsecurity/PaX. More information at: | |
544 | * https://grsecurity.net/ | |
545 | * https://pax.grsecurity.net/ | |
546 | ||
547 | config GCC_PLUGIN_RANDSTRUCT_PERFORMANCE | |
548 | bool "Use cacheline-aware structure randomization" | |
549 | depends on GCC_PLUGIN_RANDSTRUCT | |
1658dcee | 550 | depends on !COMPILE_TEST # do not reduce test coverage |
313dd1b6 KC |
551 | help |
552 | If you say Y here, the RANDSTRUCT randomization will make a | |
553 | best effort at restricting randomization to cacheline-sized | |
554 | groups of elements. It will further not randomize bitfields | |
555 | in structures. This reduces the performance hit of RANDSTRUCT | |
556 | at the cost of weakened randomization. | |
557 | ||
d148eac0 | 558 | config HAVE_STACKPROTECTOR |
19952a92 KC |
559 | bool |
560 | help | |
561 | An arch should select this symbol if: | |
19952a92 KC |
562 | - it has implemented a stack canary (e.g. __stack_chk_guard) |
563 | ||
2a61f474 MY |
564 | config CC_HAS_STACKPROTECTOR_NONE |
565 | def_bool $(cc-option,-fno-stack-protector) | |
566 | ||
050e9baa | 567 | config STACKPROTECTOR |
2a61f474 | 568 | bool "Stack Protector buffer overflow detection" |
d148eac0 | 569 | depends on HAVE_STACKPROTECTOR |
2a61f474 MY |
570 | depends on $(cc-option,-fstack-protector) |
571 | default y | |
19952a92 | 572 | help |
8779657d | 573 | This option turns on the "stack-protector" GCC feature. This |
19952a92 KC |
574 | feature puts, at the beginning of functions, a canary value on |
575 | the stack just before the return address, and validates | |
576 | the value just before actually returning. Stack based buffer | |
577 | overflows (that need to overwrite this return address) now also | |
578 | overwrite the canary, which gets detected and the attack is then | |
579 | neutralized via a kernel panic. | |
580 | ||
8779657d KC |
581 | Functions will have the stack-protector canary logic added if they |
582 | have an 8-byte or larger character array on the stack. | |
583 | ||
19952a92 | 584 | This feature requires gcc version 4.2 or above, or a distribution |
8779657d KC |
585 | gcc with the feature backported ("-fstack-protector"). |
586 | ||
587 | On an x86 "defconfig" build, this feature adds canary checks to | |
588 | about 3% of all kernel functions, which increases kernel code size | |
589 | by about 0.3%. | |
590 | ||
050e9baa | 591 | config STACKPROTECTOR_STRONG |
2a61f474 | 592 | bool "Strong Stack Protector" |
050e9baa | 593 | depends on STACKPROTECTOR |
2a61f474 MY |
594 | depends on $(cc-option,-fstack-protector-strong) |
595 | default y | |
8779657d KC |
596 | help |
597 | Functions will have the stack-protector canary logic added in any | |
598 | of the following conditions: | |
599 | ||
600 | - local variable's address used as part of the right hand side of an | |
601 | assignment or function argument | |
602 | - local variable is an array (or union containing an array), | |
603 | regardless of array type or length | |
604 | - uses register local variables | |
605 | ||
606 | This feature requires gcc version 4.9 or above, or a distribution | |
607 | gcc with the feature backported ("-fstack-protector-strong"). | |
608 | ||
609 | On an x86 "defconfig" build, this feature adds canary checks to | |
610 | about 20% of all kernel functions, which increases the kernel code | |
611 | size by about 2%. | |
612 | ||
0f60a8ef KC |
613 | config HAVE_ARCH_WITHIN_STACK_FRAMES |
614 | bool | |
615 | help | |
616 | An architecture should select this if it can walk the kernel stack | |
617 | frames to determine if an object is part of either the arguments | |
618 | or local variables (i.e. that it excludes saved return addresses, | |
619 | and similar) by implementing an inline arch_within_stack_frames(), | |
620 | which is used by CONFIG_HARDENED_USERCOPY. | |
621 | ||
91d1aa43 | 622 | config HAVE_CONTEXT_TRACKING |
2b1d5024 FW |
623 | bool |
624 | help | |
91d1aa43 FW |
625 | Provide kernel/user boundaries probes necessary for subsystems |
626 | that need it, such as userspace RCU extended quiescent state. | |
627 | Syscalls need to be wrapped inside user_exit()-user_enter() through | |
628 | the slow path using TIF_NOHZ flag. Exceptions handlers must be | |
629 | wrapped as well. Irqs are already protected inside | |
630 | rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on | |
631 | irq exit still need to be protected. | |
2b1d5024 | 632 | |
b952741c FW |
633 | config HAVE_VIRT_CPU_ACCOUNTING |
634 | bool | |
635 | ||
40565b5a SG |
636 | config ARCH_HAS_SCALED_CPUTIME |
637 | bool | |
638 | ||
554b0004 KH |
639 | config HAVE_VIRT_CPU_ACCOUNTING_GEN |
640 | bool | |
641 | default y if 64BIT | |
642 | help | |
643 | With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. | |
644 | Before enabling this option, arch code must be audited | |
645 | to ensure there are no races in concurrent read/write of | |
646 | cputime_t. For example, reading/writing 64-bit cputime_t on | |
647 | some 32-bit arches may require multiple accesses, so proper | |
648 | locking is needed to protect against concurrent accesses. | |
649 | ||
650 | ||
fdf9c356 FW |
651 | config HAVE_IRQ_TIME_ACCOUNTING |
652 | bool | |
653 | help | |
654 | Archs need to ensure they use a high enough resolution clock to | |
655 | support irq time accounting and then call enable_sched_clock_irqtime(). | |
656 | ||
15626062 GS |
657 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE |
658 | bool | |
659 | ||
a00cc7d9 MW |
660 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
661 | bool | |
662 | ||
0ddab1d2 TK |
663 | config HAVE_ARCH_HUGE_VMAP |
664 | bool | |
665 | ||
0f8975ec PE |
666 | config HAVE_ARCH_SOFT_DIRTY |
667 | bool | |
668 | ||
786d35d4 DH |
669 | config HAVE_MOD_ARCH_SPECIFIC |
670 | bool | |
671 | help | |
672 | The arch uses struct mod_arch_specific to store data. Many arches | |
673 | just need a simple module loader without arch specific data - those | |
674 | should not enable this. | |
675 | ||
676 | config MODULES_USE_ELF_RELA | |
677 | bool | |
678 | help | |
679 | Modules only use ELF RELA relocations. Modules with ELF REL | |
680 | relocations will give an error. | |
681 | ||
682 | config MODULES_USE_ELF_REL | |
683 | bool | |
684 | help | |
685 | Modules only use ELF REL relocations. Modules with ELF RELA | |
686 | relocations will give an error. | |
687 | ||
cc1f0274 FW |
688 | config HAVE_IRQ_EXIT_ON_IRQ_STACK |
689 | bool | |
690 | help | |
691 | Architecture doesn't only execute the irq handler on the irq stack | |
692 | but also irq_exit(). This way we can process softirqs on this irq | |
693 | stack instead of switching to a new one when we call __do_softirq() | |
694 | in the end of an hardirq. | |
695 | This spares a stack switch and improves cache usage on softirq | |
696 | processing. | |
697 | ||
235a8f02 KS |
698 | config PGTABLE_LEVELS |
699 | int | |
700 | default 2 | |
701 | ||
2b68f6ca KC |
702 | config ARCH_HAS_ELF_RANDOMIZE |
703 | bool | |
704 | help | |
705 | An architecture supports choosing randomized locations for | |
706 | stack, mmap, brk, and ET_DYN. Defined functions: | |
707 | - arch_mmap_rnd() | |
204db6ed | 708 | - arch_randomize_brk() |
2b68f6ca | 709 | |
d07e2259 DC |
710 | config HAVE_ARCH_MMAP_RND_BITS |
711 | bool | |
712 | help | |
713 | An arch should select this symbol if it supports setting a variable | |
714 | number of bits for use in establishing the base address for mmap | |
715 | allocations, has MMU enabled and provides values for both: | |
716 | - ARCH_MMAP_RND_BITS_MIN | |
717 | - ARCH_MMAP_RND_BITS_MAX | |
718 | ||
5f56a5df JS |
719 | config HAVE_EXIT_THREAD |
720 | bool | |
721 | help | |
722 | An architecture implements exit_thread. | |
723 | ||
d07e2259 DC |
724 | config ARCH_MMAP_RND_BITS_MIN |
725 | int | |
726 | ||
727 | config ARCH_MMAP_RND_BITS_MAX | |
728 | int | |
729 | ||
730 | config ARCH_MMAP_RND_BITS_DEFAULT | |
731 | int | |
732 | ||
733 | config ARCH_MMAP_RND_BITS | |
734 | int "Number of bits to use for ASLR of mmap base address" if EXPERT | |
735 | range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX | |
736 | default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT | |
737 | default ARCH_MMAP_RND_BITS_MIN | |
738 | depends on HAVE_ARCH_MMAP_RND_BITS | |
739 | help | |
740 | This value can be used to select the number of bits to use to | |
741 | determine the random offset to the base address of vma regions | |
742 | resulting from mmap allocations. This value will be bounded | |
743 | by the architecture's minimum and maximum supported values. | |
744 | ||
745 | This value can be changed after boot using the | |
746 | /proc/sys/vm/mmap_rnd_bits tunable | |
747 | ||
748 | config HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
749 | bool | |
750 | help | |
751 | An arch should select this symbol if it supports running applications | |
752 | in compatibility mode, supports setting a variable number of bits for | |
753 | use in establishing the base address for mmap allocations, has MMU | |
754 | enabled and provides values for both: | |
755 | - ARCH_MMAP_RND_COMPAT_BITS_MIN | |
756 | - ARCH_MMAP_RND_COMPAT_BITS_MAX | |
757 | ||
758 | config ARCH_MMAP_RND_COMPAT_BITS_MIN | |
759 | int | |
760 | ||
761 | config ARCH_MMAP_RND_COMPAT_BITS_MAX | |
762 | int | |
763 | ||
764 | config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
765 | int | |
766 | ||
767 | config ARCH_MMAP_RND_COMPAT_BITS | |
768 | int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT | |
769 | range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX | |
770 | default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
771 | default ARCH_MMAP_RND_COMPAT_BITS_MIN | |
772 | depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
773 | help | |
774 | This value can be used to select the number of bits to use to | |
775 | determine the random offset to the base address of vma regions | |
776 | resulting from mmap allocations for compatible applications This | |
777 | value will be bounded by the architecture's minimum and maximum | |
778 | supported values. | |
779 | ||
780 | This value can be changed after boot using the | |
781 | /proc/sys/vm/mmap_rnd_compat_bits tunable | |
782 | ||
1b028f78 DS |
783 | config HAVE_ARCH_COMPAT_MMAP_BASES |
784 | bool | |
785 | help | |
786 | This allows 64bit applications to invoke 32-bit mmap() syscall | |
787 | and vice-versa 32-bit applications to call 64-bit mmap(). | |
788 | Required for applications doing different bitness syscalls. | |
789 | ||
3033f14a JT |
790 | config HAVE_COPY_THREAD_TLS |
791 | bool | |
792 | help | |
793 | Architecture provides copy_thread_tls to accept tls argument via | |
794 | normal C parameter passing, rather than extracting the syscall | |
795 | argument from pt_regs. | |
796 | ||
b9ab5ebb JP |
797 | config HAVE_STACK_VALIDATION |
798 | bool | |
799 | help | |
800 | Architecture supports the 'objtool check' host tool command, which | |
801 | performs compile-time stack metadata validation. | |
802 | ||
af085d90 JP |
803 | config HAVE_RELIABLE_STACKTRACE |
804 | bool | |
805 | help | |
806 | Architecture has a save_stack_trace_tsk_reliable() function which | |
807 | only returns a stack trace if it can guarantee the trace is reliable. | |
808 | ||
468a9428 GS |
809 | config HAVE_ARCH_HASH |
810 | bool | |
811 | default n | |
812 | help | |
813 | If this is set, the architecture provides an <asm/hash.h> | |
814 | file which provides platform-specific implementations of some | |
815 | functions in <linux/hash.h> or fs/namei.c. | |
816 | ||
3a495511 WBG |
817 | config ISA_BUS_API |
818 | def_bool ISA | |
819 | ||
d2125043 AV |
820 | # |
821 | # ABI hall of shame | |
822 | # | |
823 | config CLONE_BACKWARDS | |
824 | bool | |
825 | help | |
826 | Architecture has tls passed as the 4th argument of clone(2), | |
827 | not the 5th one. | |
828 | ||
829 | config CLONE_BACKWARDS2 | |
830 | bool | |
831 | help | |
832 | Architecture has the first two arguments of clone(2) swapped. | |
833 | ||
dfa9771a MS |
834 | config CLONE_BACKWARDS3 |
835 | bool | |
836 | help | |
837 | Architecture has tls passed as the 3rd argument of clone(2), | |
838 | not the 5th one. | |
839 | ||
eaca6eae AV |
840 | config ODD_RT_SIGACTION |
841 | bool | |
842 | help | |
843 | Architecture has unusual rt_sigaction(2) arguments | |
844 | ||
0a0e8cdf AV |
845 | config OLD_SIGSUSPEND |
846 | bool | |
847 | help | |
848 | Architecture has old sigsuspend(2) syscall, of one-argument variety | |
849 | ||
850 | config OLD_SIGSUSPEND3 | |
851 | bool | |
852 | help | |
853 | Even weirder antique ABI - three-argument sigsuspend(2) | |
854 | ||
495dfbf7 AV |
855 | config OLD_SIGACTION |
856 | bool | |
857 | help | |
858 | Architecture has old sigaction(2) syscall. Nope, not the same | |
859 | as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), | |
860 | but fairly different variant of sigaction(2), thanks to OSF/1 | |
861 | compatibility... | |
862 | ||
863 | config COMPAT_OLD_SIGACTION | |
864 | bool | |
865 | ||
d4703dda DD |
866 | config 64BIT_TIME |
867 | def_bool ARCH_HAS_64BIT_TIME | |
868 | help | |
869 | This should be selected by all architectures that need to support | |
870 | new system calls with a 64-bit time_t. This is relevant on all 32-bit | |
871 | architectures, and 64-bit architectures as part of compat syscall | |
872 | handling. | |
873 | ||
17435e5f DD |
874 | config COMPAT_32BIT_TIME |
875 | def_bool (!64BIT && 64BIT_TIME) || COMPAT | |
876 | help | |
877 | This enables 32 bit time_t support in addition to 64 bit time_t support. | |
878 | This is relevant on all 32-bit architectures, and 64-bit architectures | |
879 | as part of compat syscall handling. | |
880 | ||
0d4a619b CH |
881 | config ARCH_NO_COHERENT_DMA_MMAP |
882 | bool | |
883 | ||
87a4c375 CH |
884 | config ARCH_NO_PREEMPT |
885 | bool | |
886 | ||
fff7fb0b ZZ |
887 | config CPU_NO_EFFICIENT_FFS |
888 | def_bool n | |
889 | ||
ba14a194 AL |
890 | config HAVE_ARCH_VMAP_STACK |
891 | def_bool n | |
892 | help | |
893 | An arch should select this symbol if it can support kernel stacks | |
894 | in vmalloc space. This means: | |
895 | ||
896 | - vmalloc space must be large enough to hold many kernel stacks. | |
897 | This may rule out many 32-bit architectures. | |
898 | ||
899 | - Stacks in vmalloc space need to work reliably. For example, if | |
900 | vmap page tables are created on demand, either this mechanism | |
901 | needs to work while the stack points to a virtual address with | |
902 | unpopulated page tables or arch code (switch_to() and switch_mm(), | |
903 | most likely) needs to ensure that the stack's page table entries | |
904 | are populated before running on a possibly unpopulated stack. | |
905 | ||
906 | - If the stack overflows into a guard page, something reasonable | |
907 | should happen. The definition of "reasonable" is flexible, but | |
908 | instantly rebooting without logging anything would be unfriendly. | |
909 | ||
910 | config VMAP_STACK | |
911 | default y | |
912 | bool "Use a virtually-mapped stack" | |
913 | depends on HAVE_ARCH_VMAP_STACK && !KASAN | |
914 | ---help--- | |
915 | Enable this if you want the use virtually-mapped kernel stacks | |
916 | with guard pages. This causes kernel stack overflows to be | |
917 | caught immediately rather than causing difficult-to-diagnose | |
918 | corruption. | |
919 | ||
920 | This is presently incompatible with KASAN because KASAN expects | |
921 | the stack to map directly to the KASAN shadow map using a formula | |
922 | that is incorrect if the stack is in vmalloc space. | |
923 | ||
ad21fc4f LA |
924 | config ARCH_OPTIONAL_KERNEL_RWX |
925 | def_bool n | |
926 | ||
927 | config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
928 | def_bool n | |
929 | ||
930 | config ARCH_HAS_STRICT_KERNEL_RWX | |
931 | def_bool n | |
932 | ||
0f5bf6d0 | 933 | config STRICT_KERNEL_RWX |
ad21fc4f LA |
934 | bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX |
935 | depends on ARCH_HAS_STRICT_KERNEL_RWX | |
936 | default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
937 | help | |
938 | If this is set, kernel text and rodata memory will be made read-only, | |
939 | and non-text memory will be made non-executable. This provides | |
940 | protection against certain security exploits (e.g. executing the heap | |
941 | or modifying text) | |
942 | ||
943 | These features are considered standard security practice these days. | |
944 | You should say Y here in almost all cases. | |
945 | ||
946 | config ARCH_HAS_STRICT_MODULE_RWX | |
947 | def_bool n | |
948 | ||
0f5bf6d0 | 949 | config STRICT_MODULE_RWX |
ad21fc4f LA |
950 | bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX |
951 | depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES | |
952 | default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT | |
953 | help | |
954 | If this is set, module text and rodata memory will be made read-only, | |
955 | and non-text memory will be made non-executable. This provides | |
956 | protection against certain security exploits (e.g. writing to text) | |
957 | ||
ea8c64ac CH |
958 | # select if the architecture provides an asm/dma-direct.h header |
959 | config ARCH_HAS_PHYS_TO_DMA | |
960 | bool | |
961 | ||
7a46ec0e KC |
962 | config ARCH_HAS_REFCOUNT |
963 | bool | |
964 | help | |
965 | An architecture selects this when it has implemented refcount_t | |
966 | using open coded assembly primitives that provide an optimized | |
967 | refcount_t implementation, possibly at the expense of some full | |
968 | refcount state checks of CONFIG_REFCOUNT_FULL=y. | |
969 | ||
970 | The refcount overflow check behavior, however, must be retained. | |
971 | Catching overflows is the primary security concern for protecting | |
972 | against bugs in reference counts. | |
973 | ||
fd25d19f KC |
974 | config REFCOUNT_FULL |
975 | bool "Perform full reference count validation at the expense of speed" | |
976 | help | |
977 | Enabling this switches the refcounting infrastructure from a fast | |
978 | unchecked atomic_t implementation to a fully state checked | |
979 | implementation, which can be (slightly) slower but provides protections | |
980 | against various use-after-free conditions that can be used in | |
981 | security flaw exploits. | |
982 | ||
2521f2c2 | 983 | source "kernel/gcov/Kconfig" |