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Commit | Line | Data |
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fb32e03f MD |
1 | # |
2 | # General architecture dependent options | |
3 | # | |
125e5645 | 4 | |
2965faa5 DY |
5 | config KEXEC_CORE |
6 | bool | |
7 | ||
f37486c0 TG |
8 | config HOTPLUG_SMT |
9 | bool | |
10 | ||
125e5645 | 11 | config OPROFILE |
b309a294 | 12 | tristate "OProfile system profiling" |
125e5645 MD |
13 | depends on PROFILING |
14 | depends on HAVE_OPROFILE | |
d69d59f4 | 15 | select RING_BUFFER |
9a5963eb | 16 | select RING_BUFFER_ALLOW_SWAP |
125e5645 MD |
17 | help |
18 | OProfile is a profiling system capable of profiling the | |
19 | whole system, include the kernel, kernel modules, libraries, | |
20 | and applications. | |
21 | ||
22 | If unsure, say N. | |
23 | ||
4d4036e0 JY |
24 | config OPROFILE_EVENT_MULTIPLEX |
25 | bool "OProfile multiplexing support (EXPERIMENTAL)" | |
26 | default n | |
27 | depends on OPROFILE && X86 | |
28 | help | |
29 | The number of hardware counters is limited. The multiplexing | |
30 | feature enables OProfile to gather more events than counters | |
31 | are provided by the hardware. This is realized by switching | |
32 | between events at an user specified time interval. | |
33 | ||
34 | If unsure, say N. | |
35 | ||
125e5645 | 36 | config HAVE_OPROFILE |
9ba16087 | 37 | bool |
125e5645 | 38 | |
dcfce4a0 RR |
39 | config OPROFILE_NMI_TIMER |
40 | def_bool y | |
af9feebe | 41 | depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64 |
dcfce4a0 | 42 | |
125e5645 MD |
43 | config KPROBES |
44 | bool "Kprobes" | |
05ed160e | 45 | depends on MODULES |
125e5645 | 46 | depends on HAVE_KPROBES |
05ed160e | 47 | select KALLSYMS |
125e5645 MD |
48 | help |
49 | Kprobes allows you to trap at almost any kernel address and | |
50 | execute a callback function. register_kprobe() establishes | |
51 | a probepoint and specifies the callback. Kprobes is useful | |
52 | for kernel debugging, non-intrusive instrumentation and testing. | |
53 | If in doubt, say "N". | |
54 | ||
45f81b1c | 55 | config JUMP_LABEL |
c5905afb | 56 | bool "Optimize very unlikely/likely branches" |
45f81b1c SR |
57 | depends on HAVE_ARCH_JUMP_LABEL |
58 | help | |
c5905afb IM |
59 | This option enables a transparent branch optimization that |
60 | makes certain almost-always-true or almost-always-false branch | |
61 | conditions even cheaper to execute within the kernel. | |
62 | ||
63 | Certain performance-sensitive kernel code, such as trace points, | |
64 | scheduler functionality, networking code and KVM have such | |
65 | branches and include support for this optimization technique. | |
66 | ||
45f81b1c | 67 | If it is detected that the compiler has support for "asm goto", |
c5905afb IM |
68 | the kernel will compile such branches with just a nop |
69 | instruction. When the condition flag is toggled to true, the | |
70 | nop will be converted to a jump instruction to execute the | |
71 | conditional block of instructions. | |
72 | ||
73 | This technique lowers overhead and stress on the branch prediction | |
74 | of the processor and generally makes the kernel faster. The update | |
75 | of the condition is slower, but those are always very rare. | |
45f81b1c | 76 | |
c5905afb IM |
77 | ( On 32-bit x86, the necessary options added to the compiler |
78 | flags may increase the size of the kernel slightly. ) | |
45f81b1c | 79 | |
1987c947 PZ |
80 | config STATIC_KEYS_SELFTEST |
81 | bool "Static key selftest" | |
82 | depends on JUMP_LABEL | |
83 | help | |
84 | Boot time self-test of the branch patching code. | |
85 | ||
afd66255 | 86 | config OPTPROBES |
5cc718b9 MH |
87 | def_bool y |
88 | depends on KPROBES && HAVE_OPTPROBES | |
afd66255 | 89 | depends on !PREEMPT |
afd66255 | 90 | |
e7dbfe34 MH |
91 | config KPROBES_ON_FTRACE |
92 | def_bool y | |
93 | depends on KPROBES && HAVE_KPROBES_ON_FTRACE | |
94 | depends on DYNAMIC_FTRACE_WITH_REGS | |
95 | help | |
96 | If function tracer is enabled and the arch supports full | |
97 | passing of pt_regs to function tracing, then kprobes can | |
98 | optimize on top of function tracing. | |
99 | ||
2b144498 | 100 | config UPROBES |
09294e31 | 101 | def_bool n |
2b144498 | 102 | help |
7b2d81d4 IM |
103 | Uprobes is the user-space counterpart to kprobes: they |
104 | enable instrumentation applications (such as 'perf probe') | |
105 | to establish unintrusive probes in user-space binaries and | |
106 | libraries, by executing handler functions when the probes | |
107 | are hit by user-space applications. | |
108 | ||
109 | ( These probes come in the form of single-byte breakpoints, | |
110 | managed by the kernel and kept transparent to the probed | |
111 | application. ) | |
2b144498 | 112 | |
c19fa94a JH |
113 | config HAVE_64BIT_ALIGNED_ACCESS |
114 | def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS | |
115 | help | |
116 | Some architectures require 64 bit accesses to be 64 bit | |
117 | aligned, which also requires structs containing 64 bit values | |
118 | to be 64 bit aligned too. This includes some 32 bit | |
119 | architectures which can do 64 bit accesses, as well as 64 bit | |
120 | architectures without unaligned access. | |
121 | ||
122 | This symbol should be selected by an architecture if 64 bit | |
123 | accesses are required to be 64 bit aligned in this way even | |
124 | though it is not a 64 bit architecture. | |
125 | ||
126 | See Documentation/unaligned-memory-access.txt for more | |
127 | information on the topic of unaligned memory accesses. | |
128 | ||
58340a07 | 129 | config HAVE_EFFICIENT_UNALIGNED_ACCESS |
9ba16087 | 130 | bool |
58340a07 JB |
131 | help |
132 | Some architectures are unable to perform unaligned accesses | |
133 | without the use of get_unaligned/put_unaligned. Others are | |
134 | unable to perform such accesses efficiently (e.g. trap on | |
135 | unaligned access and require fixing it up in the exception | |
136 | handler.) | |
137 | ||
138 | This symbol should be selected by an architecture if it can | |
139 | perform unaligned accesses efficiently to allow different | |
140 | code paths to be selected for these cases. Some network | |
141 | drivers, for example, could opt to not fix up alignment | |
142 | problems with received packets if doing so would not help | |
143 | much. | |
144 | ||
145 | See Documentation/unaligned-memory-access.txt for more | |
146 | information on the topic of unaligned memory accesses. | |
147 | ||
cf66bb93 DW |
148 | config ARCH_USE_BUILTIN_BSWAP |
149 | bool | |
150 | help | |
151 | Modern versions of GCC (since 4.4) have builtin functions | |
152 | for handling byte-swapping. Using these, instead of the old | |
153 | inline assembler that the architecture code provides in the | |
154 | __arch_bswapXX() macros, allows the compiler to see what's | |
155 | happening and offers more opportunity for optimisation. In | |
156 | particular, the compiler will be able to combine the byteswap | |
157 | with a nearby load or store and use load-and-swap or | |
158 | store-and-swap instructions if the architecture has them. It | |
159 | should almost *never* result in code which is worse than the | |
160 | hand-coded assembler in <asm/swab.h>. But just in case it | |
161 | does, the use of the builtins is optional. | |
162 | ||
163 | Any architecture with load-and-swap or store-and-swap | |
164 | instructions should set this. And it shouldn't hurt to set it | |
165 | on architectures that don't have such instructions. | |
166 | ||
9edddaa2 AM |
167 | config KRETPROBES |
168 | def_bool y | |
169 | depends on KPROBES && HAVE_KRETPROBES | |
170 | ||
7c68af6e AK |
171 | config USER_RETURN_NOTIFIER |
172 | bool | |
173 | depends on HAVE_USER_RETURN_NOTIFIER | |
174 | help | |
175 | Provide a kernel-internal notification when a cpu is about to | |
176 | switch to user mode. | |
177 | ||
28b2ee20 | 178 | config HAVE_IOREMAP_PROT |
9ba16087 | 179 | bool |
28b2ee20 | 180 | |
125e5645 | 181 | config HAVE_KPROBES |
9ba16087 | 182 | bool |
9edddaa2 AM |
183 | |
184 | config HAVE_KRETPROBES | |
9ba16087 | 185 | bool |
74bc7cee | 186 | |
afd66255 MH |
187 | config HAVE_OPTPROBES |
188 | bool | |
d314d74c | 189 | |
e7dbfe34 MH |
190 | config HAVE_KPROBES_ON_FTRACE |
191 | bool | |
192 | ||
42a0bb3f PM |
193 | config HAVE_NMI |
194 | bool | |
195 | ||
d314d74c | 196 | config HAVE_NMI_WATCHDOG |
42a0bb3f | 197 | depends on HAVE_NMI |
d314d74c | 198 | bool |
1f5a4ad9 RM |
199 | # |
200 | # An arch should select this if it provides all these things: | |
201 | # | |
202 | # task_pt_regs() in asm/processor.h or asm/ptrace.h | |
203 | # arch_has_single_step() if there is hardware single-step support | |
204 | # arch_has_block_step() if there is hardware block-step support | |
1f5a4ad9 RM |
205 | # asm/syscall.h supplying asm-generic/syscall.h interface |
206 | # linux/regset.h user_regset interfaces | |
207 | # CORE_DUMP_USE_REGSET #define'd in linux/elf.h | |
208 | # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} | |
209 | # TIF_NOTIFY_RESUME calls tracehook_notify_resume() | |
210 | # signal delivery calls tracehook_signal_handler() | |
211 | # | |
212 | config HAVE_ARCH_TRACEHOOK | |
9ba16087 | 213 | bool |
1f5a4ad9 | 214 | |
c64be2bb MS |
215 | config HAVE_DMA_CONTIGUOUS |
216 | bool | |
217 | ||
29d5e047 TG |
218 | config GENERIC_SMP_IDLE_THREAD |
219 | bool | |
220 | ||
485cf5da KH |
221 | config GENERIC_IDLE_POLL_SETUP |
222 | bool | |
223 | ||
a6359d1e TG |
224 | # Select if arch init_task initializer is different to init/init_task.c |
225 | config ARCH_INIT_TASK | |
a4a2eb49 TG |
226 | bool |
227 | ||
f5e10287 TG |
228 | # Select if arch has its private alloc_task_struct() function |
229 | config ARCH_TASK_STRUCT_ALLOCATOR | |
230 | bool | |
231 | ||
b235beea LT |
232 | # Select if arch has its private alloc_thread_stack() function |
233 | config ARCH_THREAD_STACK_ALLOCATOR | |
f5e10287 TG |
234 | bool |
235 | ||
5aaeb5c0 IM |
236 | # Select if arch wants to size task_struct dynamically via arch_task_struct_size: |
237 | config ARCH_WANTS_DYNAMIC_TASK_STRUCT | |
238 | bool | |
239 | ||
f850c30c HC |
240 | config HAVE_REGS_AND_STACK_ACCESS_API |
241 | bool | |
e01292b1 HC |
242 | help |
243 | This symbol should be selected by an architecure if it supports | |
244 | the API needed to access registers and stack entries from pt_regs, | |
245 | declared in asm/ptrace.h | |
246 | For example the kprobes-based event tracer needs this API. | |
f850c30c | 247 | |
9483a578 | 248 | config HAVE_CLK |
9ba16087 | 249 | bool |
9483a578 DB |
250 | help |
251 | The <linux/clk.h> calls support software clock gating and | |
252 | thus are a key power management tool on many systems. | |
253 | ||
5ee00bd4 JR |
254 | config HAVE_DMA_API_DEBUG |
255 | bool | |
36cd3c9f | 256 | |
62a038d3 P |
257 | config HAVE_HW_BREAKPOINT |
258 | bool | |
99e8c5a3 | 259 | depends on PERF_EVENTS |
62a038d3 | 260 | |
0102752e FW |
261 | config HAVE_MIXED_BREAKPOINTS_REGS |
262 | bool | |
263 | depends on HAVE_HW_BREAKPOINT | |
264 | help | |
265 | Depending on the arch implementation of hardware breakpoints, | |
266 | some of them have separate registers for data and instruction | |
267 | breakpoints addresses, others have mixed registers to store | |
268 | them but define the access type in a control register. | |
269 | Select this option if your arch implements breakpoints under the | |
270 | latter fashion. | |
271 | ||
7c68af6e AK |
272 | config HAVE_USER_RETURN_NOTIFIER |
273 | bool | |
a1922ed6 | 274 | |
c01d4323 FW |
275 | config HAVE_PERF_EVENTS_NMI |
276 | bool | |
23637d47 FW |
277 | help |
278 | System hardware can generate an NMI using the perf event | |
279 | subsystem. Also has support for calculating CPU cycle events | |
280 | to determine how many clock cycles in a given period. | |
c01d4323 | 281 | |
c5e63197 JO |
282 | config HAVE_PERF_REGS |
283 | bool | |
284 | help | |
285 | Support selective register dumps for perf events. This includes | |
286 | bit-mapping of each registers and a unique architecture id. | |
287 | ||
c5ebcedb JO |
288 | config HAVE_PERF_USER_STACK_DUMP |
289 | bool | |
290 | help | |
291 | Support user stack dumps for perf event samples. This needs | |
292 | access to the user stack pointer which is not unified across | |
293 | architectures. | |
294 | ||
bf5438fc JB |
295 | config HAVE_ARCH_JUMP_LABEL |
296 | bool | |
297 | ||
26723911 PZ |
298 | config HAVE_RCU_TABLE_FREE |
299 | bool | |
300 | ||
df013ffb HY |
301 | config ARCH_HAVE_NMI_SAFE_CMPXCHG |
302 | bool | |
303 | ||
43570fd2 HC |
304 | config HAVE_ALIGNED_STRUCT_PAGE |
305 | bool | |
306 | help | |
307 | This makes sure that struct pages are double word aligned and that | |
308 | e.g. the SLUB allocator can perform double word atomic operations | |
309 | on a struct page for better performance. However selecting this | |
310 | might increase the size of a struct page by a word. | |
311 | ||
4156153c HC |
312 | config HAVE_CMPXCHG_LOCAL |
313 | bool | |
314 | ||
2565409f HC |
315 | config HAVE_CMPXCHG_DOUBLE |
316 | bool | |
317 | ||
c1d7e01d WD |
318 | config ARCH_WANT_IPC_PARSE_VERSION |
319 | bool | |
320 | ||
321 | config ARCH_WANT_COMPAT_IPC_PARSE_VERSION | |
322 | bool | |
323 | ||
48b25c43 | 324 | config ARCH_WANT_OLD_COMPAT_IPC |
c1d7e01d | 325 | select ARCH_WANT_COMPAT_IPC_PARSE_VERSION |
48b25c43 CM |
326 | bool |
327 | ||
e2cfabdf WD |
328 | config HAVE_ARCH_SECCOMP_FILTER |
329 | bool | |
330 | help | |
fb0fadf9 | 331 | An arch should select this symbol if it provides all of these things: |
bb6ea430 WD |
332 | - syscall_get_arch() |
333 | - syscall_get_arguments() | |
334 | - syscall_rollback() | |
335 | - syscall_set_return_value() | |
fb0fadf9 WD |
336 | - SIGSYS siginfo_t support |
337 | - secure_computing is called from a ptrace_event()-safe context | |
338 | - secure_computing return value is checked and a return value of -1 | |
339 | results in the system call being skipped immediately. | |
48dc92b9 | 340 | - seccomp syscall wired up |
e2cfabdf WD |
341 | |
342 | config SECCOMP_FILTER | |
343 | def_bool y | |
344 | depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET | |
345 | help | |
346 | Enable tasks to build secure computing environments defined | |
347 | in terms of Berkeley Packet Filter programs which implement | |
348 | task-defined system call filtering polices. | |
349 | ||
350 | See Documentation/prctl/seccomp_filter.txt for details. | |
351 | ||
6b90bd4b ER |
352 | config HAVE_GCC_PLUGINS |
353 | bool | |
354 | help | |
355 | An arch should select this symbol if it supports building with | |
356 | GCC plugins. | |
357 | ||
358 | menuconfig GCC_PLUGINS | |
359 | bool "GCC plugins" | |
360 | depends on HAVE_GCC_PLUGINS | |
a519167e | 361 | depends on !COMPILE_TEST |
6b90bd4b ER |
362 | help |
363 | GCC plugins are loadable modules that provide extra features to the | |
364 | compiler. They are useful for runtime instrumentation and static analysis. | |
365 | ||
366 | See Documentation/gcc-plugins.txt for details. | |
367 | ||
0dae776c ER |
368 | config GCC_PLUGIN_CYC_COMPLEXITY |
369 | bool "Compute the cyclomatic complexity of a function" | |
370 | depends on GCC_PLUGINS | |
371 | help | |
372 | The complexity M of a function's control flow graph is defined as: | |
373 | M = E - N + 2P | |
374 | where | |
375 | ||
376 | E = the number of edges | |
377 | N = the number of nodes | |
378 | P = the number of connected components (exit nodes). | |
379 | ||
543c37cb ER |
380 | config GCC_PLUGIN_SANCOV |
381 | bool | |
382 | depends on GCC_PLUGINS | |
383 | help | |
384 | This plugin inserts a __sanitizer_cov_trace_pc() call at the start of | |
385 | basic blocks. It supports all gcc versions with plugin support (from | |
386 | gcc-4.5 on). It is based on the commit "Add fuzzing coverage support" | |
387 | by Dmitry Vyukov <dvyukov@google.com>. | |
388 | ||
38addce8 ER |
389 | config GCC_PLUGIN_LATENT_ENTROPY |
390 | bool "Generate some entropy during boot and runtime" | |
391 | depends on GCC_PLUGINS | |
392 | help | |
393 | By saying Y here the kernel will instrument some kernel code to | |
394 | extract some entropy from both original and artificially created | |
395 | program state. This will help especially embedded systems where | |
396 | there is little 'natural' source of entropy normally. The cost | |
397 | is some slowdown of the boot process (about 0.5%) and fork and | |
398 | irq processing. | |
399 | ||
400 | Note that entropy extracted this way is not cryptographically | |
401 | secure! | |
402 | ||
403 | This plugin was ported from grsecurity/PaX. More information at: | |
404 | * https://grsecurity.net/ | |
405 | * https://pax.grsecurity.net/ | |
406 | ||
19952a92 KC |
407 | config HAVE_CC_STACKPROTECTOR |
408 | bool | |
409 | help | |
410 | An arch should select this symbol if: | |
411 | - its compiler supports the -fstack-protector option | |
412 | - it has implemented a stack canary (e.g. __stack_chk_guard) | |
413 | ||
414 | config CC_STACKPROTECTOR | |
8779657d KC |
415 | def_bool n |
416 | help | |
417 | Set when a stack-protector mode is enabled, so that the build | |
418 | can enable kernel-side support for the GCC feature. | |
419 | ||
420 | choice | |
421 | prompt "Stack Protector buffer overflow detection" | |
19952a92 | 422 | depends on HAVE_CC_STACKPROTECTOR |
8779657d | 423 | default CC_STACKPROTECTOR_NONE |
19952a92 | 424 | help |
8779657d | 425 | This option turns on the "stack-protector" GCC feature. This |
19952a92 KC |
426 | feature puts, at the beginning of functions, a canary value on |
427 | the stack just before the return address, and validates | |
428 | the value just before actually returning. Stack based buffer | |
429 | overflows (that need to overwrite this return address) now also | |
430 | overwrite the canary, which gets detected and the attack is then | |
431 | neutralized via a kernel panic. | |
432 | ||
8779657d KC |
433 | config CC_STACKPROTECTOR_NONE |
434 | bool "None" | |
435 | help | |
436 | Disable "stack-protector" GCC feature. | |
437 | ||
438 | config CC_STACKPROTECTOR_REGULAR | |
439 | bool "Regular" | |
440 | select CC_STACKPROTECTOR | |
441 | help | |
442 | Functions will have the stack-protector canary logic added if they | |
443 | have an 8-byte or larger character array on the stack. | |
444 | ||
19952a92 | 445 | This feature requires gcc version 4.2 or above, or a distribution |
8779657d KC |
446 | gcc with the feature backported ("-fstack-protector"). |
447 | ||
448 | On an x86 "defconfig" build, this feature adds canary checks to | |
449 | about 3% of all kernel functions, which increases kernel code size | |
450 | by about 0.3%. | |
451 | ||
452 | config CC_STACKPROTECTOR_STRONG | |
453 | bool "Strong" | |
454 | select CC_STACKPROTECTOR | |
455 | help | |
456 | Functions will have the stack-protector canary logic added in any | |
457 | of the following conditions: | |
458 | ||
459 | - local variable's address used as part of the right hand side of an | |
460 | assignment or function argument | |
461 | - local variable is an array (or union containing an array), | |
462 | regardless of array type or length | |
463 | - uses register local variables | |
464 | ||
465 | This feature requires gcc version 4.9 or above, or a distribution | |
466 | gcc with the feature backported ("-fstack-protector-strong"). | |
467 | ||
468 | On an x86 "defconfig" build, this feature adds canary checks to | |
469 | about 20% of all kernel functions, which increases the kernel code | |
470 | size by about 2%. | |
471 | ||
472 | endchoice | |
19952a92 | 473 | |
a5967db9 SR |
474 | config THIN_ARCHIVES |
475 | bool | |
476 | help | |
477 | Select this if the architecture wants to use thin archives | |
478 | instead of ld -r to create the built-in.o files. | |
479 | ||
b67067f1 NP |
480 | config LD_DEAD_CODE_DATA_ELIMINATION |
481 | bool | |
482 | help | |
483 | Select this if the architecture wants to do dead code and | |
484 | data elimination with the linker by compiling with | |
485 | -ffunction-sections -fdata-sections and linking with | |
486 | --gc-sections. | |
487 | ||
488 | This requires that the arch annotates or otherwise protects | |
489 | its external entry points from being discarded. Linker scripts | |
490 | must also merge .text.*, .data.*, and .bss.* correctly into | |
0f4c4af0 NP |
491 | output sections. Care must be taken not to pull in unrelated |
492 | sections (e.g., '.text.init'). Typically '.' in section names | |
493 | is used to distinguish them from label names / C identifiers. | |
b67067f1 | 494 | |
0f60a8ef KC |
495 | config HAVE_ARCH_WITHIN_STACK_FRAMES |
496 | bool | |
497 | help | |
498 | An architecture should select this if it can walk the kernel stack | |
499 | frames to determine if an object is part of either the arguments | |
500 | or local variables (i.e. that it excludes saved return addresses, | |
501 | and similar) by implementing an inline arch_within_stack_frames(), | |
502 | which is used by CONFIG_HARDENED_USERCOPY. | |
503 | ||
91d1aa43 | 504 | config HAVE_CONTEXT_TRACKING |
2b1d5024 FW |
505 | bool |
506 | help | |
91d1aa43 FW |
507 | Provide kernel/user boundaries probes necessary for subsystems |
508 | that need it, such as userspace RCU extended quiescent state. | |
509 | Syscalls need to be wrapped inside user_exit()-user_enter() through | |
510 | the slow path using TIF_NOHZ flag. Exceptions handlers must be | |
511 | wrapped as well. Irqs are already protected inside | |
512 | rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on | |
513 | irq exit still need to be protected. | |
2b1d5024 | 514 | |
b952741c FW |
515 | config HAVE_VIRT_CPU_ACCOUNTING |
516 | bool | |
517 | ||
554b0004 KH |
518 | config HAVE_VIRT_CPU_ACCOUNTING_GEN |
519 | bool | |
520 | default y if 64BIT | |
521 | help | |
522 | With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. | |
523 | Before enabling this option, arch code must be audited | |
524 | to ensure there are no races in concurrent read/write of | |
525 | cputime_t. For example, reading/writing 64-bit cputime_t on | |
526 | some 32-bit arches may require multiple accesses, so proper | |
527 | locking is needed to protect against concurrent accesses. | |
528 | ||
529 | ||
fdf9c356 FW |
530 | config HAVE_IRQ_TIME_ACCOUNTING |
531 | bool | |
532 | help | |
533 | Archs need to ensure they use a high enough resolution clock to | |
534 | support irq time accounting and then call enable_sched_clock_irqtime(). | |
535 | ||
15626062 GS |
536 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE |
537 | bool | |
538 | ||
0ddab1d2 TK |
539 | config HAVE_ARCH_HUGE_VMAP |
540 | bool | |
541 | ||
0f8975ec PE |
542 | config HAVE_ARCH_SOFT_DIRTY |
543 | bool | |
544 | ||
786d35d4 DH |
545 | config HAVE_MOD_ARCH_SPECIFIC |
546 | bool | |
547 | help | |
548 | The arch uses struct mod_arch_specific to store data. Many arches | |
549 | just need a simple module loader without arch specific data - those | |
550 | should not enable this. | |
551 | ||
552 | config MODULES_USE_ELF_RELA | |
553 | bool | |
554 | help | |
555 | Modules only use ELF RELA relocations. Modules with ELF REL | |
556 | relocations will give an error. | |
557 | ||
558 | config MODULES_USE_ELF_REL | |
559 | bool | |
560 | help | |
561 | Modules only use ELF REL relocations. Modules with ELF RELA | |
562 | relocations will give an error. | |
563 | ||
b92021b0 RR |
564 | config HAVE_UNDERSCORE_SYMBOL_PREFIX |
565 | bool | |
566 | help | |
567 | Some architectures generate an _ in front of C symbols; things like | |
568 | module loading and assembly files need to know about this. | |
569 | ||
cc1f0274 FW |
570 | config HAVE_IRQ_EXIT_ON_IRQ_STACK |
571 | bool | |
572 | help | |
573 | Architecture doesn't only execute the irq handler on the irq stack | |
574 | but also irq_exit(). This way we can process softirqs on this irq | |
575 | stack instead of switching to a new one when we call __do_softirq() | |
576 | in the end of an hardirq. | |
577 | This spares a stack switch and improves cache usage on softirq | |
578 | processing. | |
579 | ||
235a8f02 KS |
580 | config PGTABLE_LEVELS |
581 | int | |
582 | default 2 | |
583 | ||
2b68f6ca KC |
584 | config ARCH_HAS_ELF_RANDOMIZE |
585 | bool | |
586 | help | |
587 | An architecture supports choosing randomized locations for | |
588 | stack, mmap, brk, and ET_DYN. Defined functions: | |
589 | - arch_mmap_rnd() | |
204db6ed | 590 | - arch_randomize_brk() |
2b68f6ca | 591 | |
d07e2259 DC |
592 | config HAVE_ARCH_MMAP_RND_BITS |
593 | bool | |
594 | help | |
595 | An arch should select this symbol if it supports setting a variable | |
596 | number of bits for use in establishing the base address for mmap | |
597 | allocations, has MMU enabled and provides values for both: | |
598 | - ARCH_MMAP_RND_BITS_MIN | |
599 | - ARCH_MMAP_RND_BITS_MAX | |
600 | ||
5f56a5df JS |
601 | config HAVE_EXIT_THREAD |
602 | bool | |
603 | help | |
604 | An architecture implements exit_thread. | |
605 | ||
d07e2259 DC |
606 | config ARCH_MMAP_RND_BITS_MIN |
607 | int | |
608 | ||
609 | config ARCH_MMAP_RND_BITS_MAX | |
610 | int | |
611 | ||
612 | config ARCH_MMAP_RND_BITS_DEFAULT | |
613 | int | |
614 | ||
615 | config ARCH_MMAP_RND_BITS | |
616 | int "Number of bits to use for ASLR of mmap base address" if EXPERT | |
617 | range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX | |
618 | default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT | |
619 | default ARCH_MMAP_RND_BITS_MIN | |
620 | depends on HAVE_ARCH_MMAP_RND_BITS | |
621 | help | |
622 | This value can be used to select the number of bits to use to | |
623 | determine the random offset to the base address of vma regions | |
624 | resulting from mmap allocations. This value will be bounded | |
625 | by the architecture's minimum and maximum supported values. | |
626 | ||
627 | This value can be changed after boot using the | |
628 | /proc/sys/vm/mmap_rnd_bits tunable | |
629 | ||
630 | config HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
631 | bool | |
632 | help | |
633 | An arch should select this symbol if it supports running applications | |
634 | in compatibility mode, supports setting a variable number of bits for | |
635 | use in establishing the base address for mmap allocations, has MMU | |
636 | enabled and provides values for both: | |
637 | - ARCH_MMAP_RND_COMPAT_BITS_MIN | |
638 | - ARCH_MMAP_RND_COMPAT_BITS_MAX | |
639 | ||
640 | config ARCH_MMAP_RND_COMPAT_BITS_MIN | |
641 | int | |
642 | ||
643 | config ARCH_MMAP_RND_COMPAT_BITS_MAX | |
644 | int | |
645 | ||
646 | config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
647 | int | |
648 | ||
649 | config ARCH_MMAP_RND_COMPAT_BITS | |
650 | int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT | |
651 | range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX | |
652 | default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT | |
653 | default ARCH_MMAP_RND_COMPAT_BITS_MIN | |
654 | depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS | |
655 | help | |
656 | This value can be used to select the number of bits to use to | |
657 | determine the random offset to the base address of vma regions | |
658 | resulting from mmap allocations for compatible applications This | |
659 | value will be bounded by the architecture's minimum and maximum | |
660 | supported values. | |
661 | ||
662 | This value can be changed after boot using the | |
663 | /proc/sys/vm/mmap_rnd_compat_bits tunable | |
664 | ||
3033f14a JT |
665 | config HAVE_COPY_THREAD_TLS |
666 | bool | |
667 | help | |
668 | Architecture provides copy_thread_tls to accept tls argument via | |
669 | normal C parameter passing, rather than extracting the syscall | |
670 | argument from pt_regs. | |
671 | ||
b9ab5ebb JP |
672 | config HAVE_STACK_VALIDATION |
673 | bool | |
674 | help | |
675 | Architecture supports the 'objtool check' host tool command, which | |
676 | performs compile-time stack metadata validation. | |
677 | ||
468a9428 GS |
678 | config HAVE_ARCH_HASH |
679 | bool | |
680 | default n | |
681 | help | |
682 | If this is set, the architecture provides an <asm/hash.h> | |
683 | file which provides platform-specific implementations of some | |
684 | functions in <linux/hash.h> or fs/namei.c. | |
685 | ||
3a495511 WBG |
686 | config ISA_BUS_API |
687 | def_bool ISA | |
688 | ||
d2125043 AV |
689 | # |
690 | # ABI hall of shame | |
691 | # | |
692 | config CLONE_BACKWARDS | |
693 | bool | |
694 | help | |
695 | Architecture has tls passed as the 4th argument of clone(2), | |
696 | not the 5th one. | |
697 | ||
698 | config CLONE_BACKWARDS2 | |
699 | bool | |
700 | help | |
701 | Architecture has the first two arguments of clone(2) swapped. | |
702 | ||
dfa9771a MS |
703 | config CLONE_BACKWARDS3 |
704 | bool | |
705 | help | |
706 | Architecture has tls passed as the 3rd argument of clone(2), | |
707 | not the 5th one. | |
708 | ||
eaca6eae AV |
709 | config ODD_RT_SIGACTION |
710 | bool | |
711 | help | |
712 | Architecture has unusual rt_sigaction(2) arguments | |
713 | ||
0a0e8cdf AV |
714 | config OLD_SIGSUSPEND |
715 | bool | |
716 | help | |
717 | Architecture has old sigsuspend(2) syscall, of one-argument variety | |
718 | ||
719 | config OLD_SIGSUSPEND3 | |
720 | bool | |
721 | help | |
722 | Even weirder antique ABI - three-argument sigsuspend(2) | |
723 | ||
495dfbf7 AV |
724 | config OLD_SIGACTION |
725 | bool | |
726 | help | |
727 | Architecture has old sigaction(2) syscall. Nope, not the same | |
728 | as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), | |
729 | but fairly different variant of sigaction(2), thanks to OSF/1 | |
730 | compatibility... | |
731 | ||
732 | config COMPAT_OLD_SIGACTION | |
733 | bool | |
734 | ||
0d4a619b CH |
735 | config ARCH_NO_COHERENT_DMA_MMAP |
736 | bool | |
737 | ||
fff7fb0b ZZ |
738 | config CPU_NO_EFFICIENT_FFS |
739 | def_bool n | |
740 | ||
ba14a194 AL |
741 | config HAVE_ARCH_VMAP_STACK |
742 | def_bool n | |
743 | help | |
744 | An arch should select this symbol if it can support kernel stacks | |
745 | in vmalloc space. This means: | |
746 | ||
747 | - vmalloc space must be large enough to hold many kernel stacks. | |
748 | This may rule out many 32-bit architectures. | |
749 | ||
750 | - Stacks in vmalloc space need to work reliably. For example, if | |
751 | vmap page tables are created on demand, either this mechanism | |
752 | needs to work while the stack points to a virtual address with | |
753 | unpopulated page tables or arch code (switch_to() and switch_mm(), | |
754 | most likely) needs to ensure that the stack's page table entries | |
755 | are populated before running on a possibly unpopulated stack. | |
756 | ||
757 | - If the stack overflows into a guard page, something reasonable | |
758 | should happen. The definition of "reasonable" is flexible, but | |
759 | instantly rebooting without logging anything would be unfriendly. | |
760 | ||
761 | config VMAP_STACK | |
762 | default y | |
763 | bool "Use a virtually-mapped stack" | |
764 | depends on HAVE_ARCH_VMAP_STACK && !KASAN | |
765 | ---help--- | |
766 | Enable this if you want the use virtually-mapped kernel stacks | |
767 | with guard pages. This causes kernel stack overflows to be | |
768 | caught immediately rather than causing difficult-to-diagnose | |
769 | corruption. | |
770 | ||
771 | This is presently incompatible with KASAN because KASAN expects | |
772 | the stack to map directly to the KASAN shadow map using a formula | |
773 | that is incorrect if the stack is in vmalloc space. | |
774 | ||
2521f2c2 | 775 | source "kernel/gcov/Kconfig" |