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Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001#
2# General architecture dependent options
3#
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05004
Dave Young2965faa2015-09-09 15:38:55 -07005config KEXEC_CORE
6 bool
7
Thiago Jung Bauermann467d2782016-12-19 16:22:32 -08008config HAVE_IMA_KEXEC
9 bool
10
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050011config OPROFILE
Robert Richterb309a292010-02-26 15:01:23 +010012 tristate "OProfile system profiling"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050013 depends on PROFILING
14 depends on HAVE_OPROFILE
Ingo Molnard69d59f2008-12-12 09:38:57 +010015 select RING_BUFFER
Christian Borntraeger9a5963e2009-09-16 21:56:49 +020016 select RING_BUFFER_ALLOW_SWAP
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050017 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
Jason Yeh4d4036e2009-07-08 13:49:38 +020024config 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
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050036config HAVE_OPROFILE
Jan Beulich9ba16082008-10-15 22:01:38 -070037 bool
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050038
Robert Richterdcfce4a2011-10-11 17:11:08 +020039config OPROFILE_NMI_TIMER
40 def_bool y
Anton Blanchardaf9feeb2015-04-09 12:52:55 +100041 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64
Robert Richterdcfce4a2011-10-11 17:11:08 +020042
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050043config KPROBES
44 bool "Kprobes"
Masami Hiramatsu05ed1602010-09-13 19:25:41 +090045 depends on MODULES
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050046 depends on HAVE_KPROBES
Masami Hiramatsu05ed1602010-09-13 19:25:41 +090047 select KALLSYMS
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050048 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
Steven Rostedt45f81b12010-10-29 12:33:43 -040055config JUMP_LABEL
Ingo Molnarc5905af2012-02-24 08:31:31 +010056 bool "Optimize very unlikely/likely branches"
Steven Rostedt45f81b12010-10-29 12:33:43 -040057 depends on HAVE_ARCH_JUMP_LABEL
58 help
Ingo Molnarc5905af2012-02-24 08:31:31 +010059 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.
Steven Rostedt45f81b12010-10-29 12:33:43 -040062
Ingo Molnarc5905af2012-02-24 08:31:31 +010063 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
67 If it is detected that the compiler has support for "asm goto",
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.
76
77 ( On 32-bit x86, the necessary options added to the compiler
78 flags may increase the size of the kernel slightly. )
Steven Rostedt45f81b12010-10-29 12:33:43 -040079
Peter Zijlstra1987c942015-07-27 18:32:09 +020080config 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
Masami Hiramatsuafd66252010-02-25 08:34:07 -050086config OPTPROBES
Masami Hiramatsu5cc718b2010-03-15 13:00:54 -040087 def_bool y
88 depends on KPROBES && HAVE_OPTPROBES
Masami Hiramatsuafd66252010-02-25 08:34:07 -050089 depends on !PREEMPT
Masami Hiramatsuafd66252010-02-25 08:34:07 -050090
Masami Hiramatsue7dbfe32012-09-28 17:15:20 +090091config 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
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530100config UPROBES
David A. Long09294e32014-03-07 10:32:22 -0500101 def_bool n
Allen Paise8f4aa62016-10-13 10:06:13 +0530102 depends on ARCH_SUPPORTS_UPROBES
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530103 help
Ingo Molnar7b2d81d2012-02-17 09:27:41 +0100104 Uprobes is the user-space counterpart to kprobes: they
105 enable instrumentation applications (such as 'perf probe')
106 to establish unintrusive probes in user-space binaries and
107 libraries, by executing handler functions when the probes
108 are hit by user-space applications.
109
110 ( These probes come in the form of single-byte breakpoints,
111 managed by the kernel and kept transparent to the probed
112 application. )
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530113
James Hoganc19fa942012-05-30 11:23:23 +0100114config HAVE_64BIT_ALIGNED_ACCESS
115 def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
116 help
117 Some architectures require 64 bit accesses to be 64 bit
118 aligned, which also requires structs containing 64 bit values
119 to be 64 bit aligned too. This includes some 32 bit
120 architectures which can do 64 bit accesses, as well as 64 bit
121 architectures without unaligned access.
122
123 This symbol should be selected by an architecture if 64 bit
124 accesses are required to be 64 bit aligned in this way even
125 though it is not a 64 bit architecture.
126
127 See Documentation/unaligned-memory-access.txt for more
128 information on the topic of unaligned memory accesses.
129
Johannes Berg58340a02008-07-25 01:45:33 -0700130config HAVE_EFFICIENT_UNALIGNED_ACCESS
Jan Beulich9ba16082008-10-15 22:01:38 -0700131 bool
Johannes Berg58340a02008-07-25 01:45:33 -0700132 help
133 Some architectures are unable to perform unaligned accesses
134 without the use of get_unaligned/put_unaligned. Others are
135 unable to perform such accesses efficiently (e.g. trap on
136 unaligned access and require fixing it up in the exception
137 handler.)
138
139 This symbol should be selected by an architecture if it can
140 perform unaligned accesses efficiently to allow different
141 code paths to be selected for these cases. Some network
142 drivers, for example, could opt to not fix up alignment
143 problems with received packets if doing so would not help
144 much.
145
146 See Documentation/unaligned-memory-access.txt for more
147 information on the topic of unaligned memory accesses.
148
David Woodhousecf66bb92012-12-03 16:25:40 +0000149config ARCH_USE_BUILTIN_BSWAP
150 bool
151 help
152 Modern versions of GCC (since 4.4) have builtin functions
153 for handling byte-swapping. Using these, instead of the old
154 inline assembler that the architecture code provides in the
155 __arch_bswapXX() macros, allows the compiler to see what's
156 happening and offers more opportunity for optimisation. In
157 particular, the compiler will be able to combine the byteswap
158 with a nearby load or store and use load-and-swap or
159 store-and-swap instructions if the architecture has them. It
160 should almost *never* result in code which is worse than the
161 hand-coded assembler in <asm/swab.h>. But just in case it
162 does, the use of the builtins is optional.
163
164 Any architecture with load-and-swap or store-and-swap
165 instructions should set this. And it shouldn't hurt to set it
166 on architectures that don't have such instructions.
167
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -0800168config KRETPROBES
169 def_bool y
170 depends on KPROBES && HAVE_KRETPROBES
171
Avi Kivity7c68af62009-09-19 09:40:22 +0300172config USER_RETURN_NOTIFIER
173 bool
174 depends on HAVE_USER_RETURN_NOTIFIER
175 help
176 Provide a kernel-internal notification when a cpu is about to
177 switch to user mode.
178
Rik van Riel28b2ee22008-07-23 21:27:05 -0700179config HAVE_IOREMAP_PROT
Jan Beulich9ba16082008-10-15 22:01:38 -0700180 bool
Rik van Riel28b2ee22008-07-23 21:27:05 -0700181
Mathieu Desnoyers125e5642008-02-02 15:10:36 -0500182config HAVE_KPROBES
Jan Beulich9ba16082008-10-15 22:01:38 -0700183 bool
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -0800184
185config HAVE_KRETPROBES
Jan Beulich9ba16082008-10-15 22:01:38 -0700186 bool
Arthur Kepner74bc7ce2008-04-29 01:00:30 -0700187
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500188config HAVE_OPTPROBES
189 bool
Cong Wangd314d742012-03-23 15:01:51 -0700190
Masami Hiramatsue7dbfe32012-09-28 17:15:20 +0900191config HAVE_KPROBES_ON_FTRACE
192 bool
193
Petr Mladek42a0bb32016-05-20 17:00:33 -0700194config HAVE_NMI
195 bool
196
Cong Wangd314d742012-03-23 15:01:51 -0700197config HAVE_NMI_WATCHDOG
Petr Mladek42a0bb32016-05-20 17:00:33 -0700198 depends on HAVE_NMI
Cong Wangd314d742012-03-23 15:01:51 -0700199 bool
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700200#
201# An arch should select this if it provides all these things:
202#
203# task_pt_regs() in asm/processor.h or asm/ptrace.h
204# arch_has_single_step() if there is hardware single-step support
205# arch_has_block_step() if there is hardware block-step support
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700206# asm/syscall.h supplying asm-generic/syscall.h interface
207# linux/regset.h user_regset interfaces
208# CORE_DUMP_USE_REGSET #define'd in linux/elf.h
209# TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit}
210# TIF_NOTIFY_RESUME calls tracehook_notify_resume()
211# signal delivery calls tracehook_signal_handler()
212#
213config HAVE_ARCH_TRACEHOOK
Jan Beulich9ba16082008-10-15 22:01:38 -0700214 bool
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700215
Marek Szyprowskic64be2b2011-12-29 13:09:51 +0100216config HAVE_DMA_CONTIGUOUS
217 bool
218
Thomas Gleixner29d5e042012-04-20 13:05:45 +0000219config GENERIC_SMP_IDLE_THREAD
220 bool
221
Kevin Hilman485cf5d2013-04-24 17:19:13 -0700222config GENERIC_IDLE_POLL_SETUP
223 bool
224
Daniel Borkmannd2852a22017-02-21 16:09:33 +0100225# Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
226config ARCH_HAS_SET_MEMORY
227 bool
228
Thomas Gleixnera6359d12012-05-03 09:03:02 +0000229# Select if arch init_task initializer is different to init/init_task.c
230config ARCH_INIT_TASK
Thomas Gleixnera4a2eb42012-05-03 09:02:48 +0000231 bool
232
Thomas Gleixnerf5e10282012-05-05 15:05:48 +0000233# Select if arch has its private alloc_task_struct() function
234config ARCH_TASK_STRUCT_ALLOCATOR
235 bool
236
Linus Torvaldsb235bee2016-06-24 15:09:37 -0700237# Select if arch has its private alloc_thread_stack() function
238config ARCH_THREAD_STACK_ALLOCATOR
Thomas Gleixnerf5e10282012-05-05 15:05:48 +0000239 bool
240
Ingo Molnar5aaeb5c2015-07-17 12:28:12 +0200241# Select if arch wants to size task_struct dynamically via arch_task_struct_size:
242config ARCH_WANTS_DYNAMIC_TASK_STRUCT
243 bool
244
Heiko Carstensf850c30c2010-02-10 17:25:17 +0100245config HAVE_REGS_AND_STACK_ACCESS_API
246 bool
Heiko Carstense01292b2010-02-18 14:25:21 +0100247 help
248 This symbol should be selected by an architecure if it supports
249 the API needed to access registers and stack entries from pt_regs,
250 declared in asm/ptrace.h
251 For example the kprobes-based event tracer needs this API.
Heiko Carstensf850c30c2010-02-10 17:25:17 +0100252
David Brownell9483a572008-07-23 21:26:48 -0700253config HAVE_CLK
Jan Beulich9ba16082008-10-15 22:01:38 -0700254 bool
David Brownell9483a572008-07-23 21:26:48 -0700255 help
256 The <linux/clk.h> calls support software clock gating and
257 thus are a key power management tool on many systems.
258
Joerg Roedel5ee00bd2009-01-09 12:14:24 +0100259config HAVE_DMA_API_DEBUG
260 bool
Heiko Carstens36cd3c92009-04-09 18:48:34 +0200261
K.Prasad62a038d2009-06-01 23:43:33 +0530262config HAVE_HW_BREAKPOINT
263 bool
Frederic Weisbecker99e8c5a2009-12-17 01:33:54 +0100264 depends on PERF_EVENTS
K.Prasad62a038d2009-06-01 23:43:33 +0530265
Frederic Weisbecker01027522010-04-11 18:55:56 +0200266config HAVE_MIXED_BREAKPOINTS_REGS
267 bool
268 depends on HAVE_HW_BREAKPOINT
269 help
270 Depending on the arch implementation of hardware breakpoints,
271 some of them have separate registers for data and instruction
272 breakpoints addresses, others have mixed registers to store
273 them but define the access type in a control register.
274 Select this option if your arch implements breakpoints under the
275 latter fashion.
276
Avi Kivity7c68af62009-09-19 09:40:22 +0300277config HAVE_USER_RETURN_NOTIFIER
278 bool
Ingo Molnara1922ed2009-09-07 08:19:51 +0200279
Frederic Weisbeckerc01d4322010-05-15 22:57:48 +0200280config HAVE_PERF_EVENTS_NMI
281 bool
Frederic Weisbecker23637d42010-05-15 23:15:20 +0200282 help
283 System hardware can generate an NMI using the perf event
284 subsystem. Also has support for calculating CPU cycle events
285 to determine how many clock cycles in a given period.
Frederic Weisbeckerc01d4322010-05-15 22:57:48 +0200286
Jiri Olsac5e63192012-08-07 15:20:36 +0200287config HAVE_PERF_REGS
288 bool
289 help
290 Support selective register dumps for perf events. This includes
291 bit-mapping of each registers and a unique architecture id.
292
Jiri Olsac5ebced2012-08-07 15:20:40 +0200293config HAVE_PERF_USER_STACK_DUMP
294 bool
295 help
296 Support user stack dumps for perf event samples. This needs
297 access to the user stack pointer which is not unified across
298 architectures.
299
Jason Baronbf5438fc2010-09-17 11:09:00 -0400300config HAVE_ARCH_JUMP_LABEL
301 bool
302
Peter Zijlstra26723912011-05-24 17:12:00 -0700303config HAVE_RCU_TABLE_FREE
304 bool
305
Huang Yingdf013ff2011-07-13 13:14:22 +0800306config ARCH_HAVE_NMI_SAFE_CMPXCHG
307 bool
308
Heiko Carstens43570fd2012-01-12 17:17:27 -0800309config HAVE_ALIGNED_STRUCT_PAGE
310 bool
311 help
312 This makes sure that struct pages are double word aligned and that
313 e.g. the SLUB allocator can perform double word atomic operations
314 on a struct page for better performance. However selecting this
315 might increase the size of a struct page by a word.
316
Heiko Carstens41561532012-01-12 17:17:30 -0800317config HAVE_CMPXCHG_LOCAL
318 bool
319
Heiko Carstens25654092012-01-12 17:17:33 -0800320config HAVE_CMPXCHG_DOUBLE
321 bool
322
Will Deaconc1d7e012012-07-30 14:42:46 -0700323config ARCH_WANT_IPC_PARSE_VERSION
324 bool
325
326config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
327 bool
328
Chris Metcalf48b25c42012-03-15 13:13:38 -0400329config ARCH_WANT_OLD_COMPAT_IPC
Will Deaconc1d7e012012-07-30 14:42:46 -0700330 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
Chris Metcalf48b25c42012-03-15 13:13:38 -0400331 bool
332
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500333config HAVE_ARCH_SECCOMP_FILTER
334 bool
335 help
Will Drewryfb0fadf2012-04-12 16:48:02 -0500336 An arch should select this symbol if it provides all of these things:
Will Drewrybb6ea432012-04-12 16:48:01 -0500337 - syscall_get_arch()
338 - syscall_get_arguments()
339 - syscall_rollback()
340 - syscall_set_return_value()
Will Drewryfb0fadf2012-04-12 16:48:02 -0500341 - SIGSYS siginfo_t support
342 - secure_computing is called from a ptrace_event()-safe context
343 - secure_computing return value is checked and a return value of -1
344 results in the system call being skipped immediately.
Kees Cook48dc92b2014-06-25 16:08:24 -0700345 - seccomp syscall wired up
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500346
347config SECCOMP_FILTER
348 def_bool y
349 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
350 help
351 Enable tasks to build secure computing environments defined
352 in terms of Berkeley Packet Filter programs which implement
353 task-defined system call filtering polices.
354
355 See Documentation/prctl/seccomp_filter.txt for details.
356
Emese Revfy6b90bd42016-05-24 00:09:38 +0200357config HAVE_GCC_PLUGINS
358 bool
359 help
360 An arch should select this symbol if it supports building with
361 GCC plugins.
362
363menuconfig GCC_PLUGINS
364 bool "GCC plugins"
365 depends on HAVE_GCC_PLUGINS
Kees Cooka519167e2016-06-11 09:09:28 -0700366 depends on !COMPILE_TEST
Emese Revfy6b90bd42016-05-24 00:09:38 +0200367 help
368 GCC plugins are loadable modules that provide extra features to the
369 compiler. They are useful for runtime instrumentation and static analysis.
370
371 See Documentation/gcc-plugins.txt for details.
372
Emese Revfy0dae7762016-05-24 00:10:35 +0200373config GCC_PLUGIN_CYC_COMPLEXITY
Kees Cook215e2aa2016-11-08 16:27:03 -0800374 bool "Compute the cyclomatic complexity of a function" if EXPERT
Emese Revfy0dae7762016-05-24 00:10:35 +0200375 depends on GCC_PLUGINS
Kees Cook215e2aa2016-11-08 16:27:03 -0800376 depends on !COMPILE_TEST
Emese Revfy0dae7762016-05-24 00:10:35 +0200377 help
378 The complexity M of a function's control flow graph is defined as:
379 M = E - N + 2P
380 where
381
382 E = the number of edges
383 N = the number of nodes
384 P = the number of connected components (exit nodes).
385
Kees Cook215e2aa2016-11-08 16:27:03 -0800386 Enabling this plugin reports the complexity to stderr during the
387 build. It mainly serves as a simple example of how to create a
388 gcc plugin for the kernel.
389
Emese Revfy543c37c2016-05-24 00:11:37 +0200390config GCC_PLUGIN_SANCOV
391 bool
392 depends on GCC_PLUGINS
393 help
394 This plugin inserts a __sanitizer_cov_trace_pc() call at the start of
395 basic blocks. It supports all gcc versions with plugin support (from
396 gcc-4.5 on). It is based on the commit "Add fuzzing coverage support"
397 by Dmitry Vyukov <dvyukov@google.com>.
398
Emese Revfy38addce2016-06-20 20:41:19 +0200399config GCC_PLUGIN_LATENT_ENTROPY
400 bool "Generate some entropy during boot and runtime"
401 depends on GCC_PLUGINS
402 help
403 By saying Y here the kernel will instrument some kernel code to
404 extract some entropy from both original and artificially created
405 program state. This will help especially embedded systems where
406 there is little 'natural' source of entropy normally. The cost
407 is some slowdown of the boot process (about 0.5%) and fork and
408 irq processing.
409
410 Note that entropy extracted this way is not cryptographically
411 secure!
412
413 This plugin was ported from grsecurity/PaX. More information at:
414 * https://grsecurity.net/
415 * https://pax.grsecurity.net/
416
Kees Cook19952a92013-12-19 11:35:58 -0800417config HAVE_CC_STACKPROTECTOR
418 bool
419 help
420 An arch should select this symbol if:
421 - its compiler supports the -fstack-protector option
422 - it has implemented a stack canary (e.g. __stack_chk_guard)
423
424config CC_STACKPROTECTOR
Kees Cook87796572013-12-19 11:35:59 -0800425 def_bool n
Kees Cook19952a92013-12-19 11:35:58 -0800426 help
Kees Cook87796572013-12-19 11:35:59 -0800427 Set when a stack-protector mode is enabled, so that the build
428 can enable kernel-side support for the GCC feature.
429
430choice
431 prompt "Stack Protector buffer overflow detection"
432 depends on HAVE_CC_STACKPROTECTOR
433 default CC_STACKPROTECTOR_NONE
434 help
435 This option turns on the "stack-protector" GCC feature. This
Kees Cook19952a92013-12-19 11:35:58 -0800436 feature puts, at the beginning of functions, a canary value on
437 the stack just before the return address, and validates
438 the value just before actually returning. Stack based buffer
439 overflows (that need to overwrite this return address) now also
440 overwrite the canary, which gets detected and the attack is then
441 neutralized via a kernel panic.
442
Kees Cook87796572013-12-19 11:35:59 -0800443config CC_STACKPROTECTOR_NONE
444 bool "None"
445 help
446 Disable "stack-protector" GCC feature.
447
448config CC_STACKPROTECTOR_REGULAR
449 bool "Regular"
450 select CC_STACKPROTECTOR
451 help
452 Functions will have the stack-protector canary logic added if they
453 have an 8-byte or larger character array on the stack.
454
Kees Cook19952a92013-12-19 11:35:58 -0800455 This feature requires gcc version 4.2 or above, or a distribution
Kees Cook87796572013-12-19 11:35:59 -0800456 gcc with the feature backported ("-fstack-protector").
457
458 On an x86 "defconfig" build, this feature adds canary checks to
459 about 3% of all kernel functions, which increases kernel code size
460 by about 0.3%.
461
462config CC_STACKPROTECTOR_STRONG
463 bool "Strong"
464 select CC_STACKPROTECTOR
465 help
466 Functions will have the stack-protector canary logic added in any
467 of the following conditions:
468
469 - local variable's address used as part of the right hand side of an
470 assignment or function argument
471 - local variable is an array (or union containing an array),
472 regardless of array type or length
473 - uses register local variables
474
475 This feature requires gcc version 4.9 or above, or a distribution
476 gcc with the feature backported ("-fstack-protector-strong").
477
478 On an x86 "defconfig" build, this feature adds canary checks to
479 about 20% of all kernel functions, which increases the kernel code
480 size by about 2%.
481
482endchoice
Kees Cook19952a92013-12-19 11:35:58 -0800483
Stephen Rothwella5967db2016-08-24 22:29:19 +1000484config THIN_ARCHIVES
485 bool
486 help
487 Select this if the architecture wants to use thin archives
488 instead of ld -r to create the built-in.o files.
489
Nicholas Pigginb67067f2016-08-24 22:29:20 +1000490config LD_DEAD_CODE_DATA_ELIMINATION
491 bool
492 help
493 Select this if the architecture wants to do dead code and
494 data elimination with the linker by compiling with
495 -ffunction-sections -fdata-sections and linking with
496 --gc-sections.
497
498 This requires that the arch annotates or otherwise protects
499 its external entry points from being discarded. Linker scripts
500 must also merge .text.*, .data.*, and .bss.* correctly into
Nicholas Piggin0f4c4af2016-09-14 12:24:03 +1000501 output sections. Care must be taken not to pull in unrelated
502 sections (e.g., '.text.init'). Typically '.' in section names
503 is used to distinguish them from label names / C identifiers.
Nicholas Pigginb67067f2016-08-24 22:29:20 +1000504
Kees Cook0f60a8e2016-07-12 16:19:48 -0700505config HAVE_ARCH_WITHIN_STACK_FRAMES
506 bool
507 help
508 An architecture should select this if it can walk the kernel stack
509 frames to determine if an object is part of either the arguments
510 or local variables (i.e. that it excludes saved return addresses,
511 and similar) by implementing an inline arch_within_stack_frames(),
512 which is used by CONFIG_HARDENED_USERCOPY.
513
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100514config HAVE_CONTEXT_TRACKING
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200515 bool
516 help
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100517 Provide kernel/user boundaries probes necessary for subsystems
518 that need it, such as userspace RCU extended quiescent state.
519 Syscalls need to be wrapped inside user_exit()-user_enter() through
520 the slow path using TIF_NOHZ flag. Exceptions handlers must be
521 wrapped as well. Irqs are already protected inside
522 rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on
523 irq exit still need to be protected.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200524
Frederic Weisbeckerb9527412012-06-16 15:39:34 +0200525config HAVE_VIRT_CPU_ACCOUNTING
526 bool
527
Stanislaw Gruszka40565b52016-11-15 03:06:51 +0100528config ARCH_HAS_SCALED_CPUTIME
529 bool
530
Kevin Hilman554b0002013-09-16 15:28:21 -0700531config HAVE_VIRT_CPU_ACCOUNTING_GEN
532 bool
533 default y if 64BIT
534 help
535 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
536 Before enabling this option, arch code must be audited
537 to ensure there are no races in concurrent read/write of
538 cputime_t. For example, reading/writing 64-bit cputime_t on
539 some 32-bit arches may require multiple accesses, so proper
540 locking is needed to protect against concurrent accesses.
541
542
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200543config HAVE_IRQ_TIME_ACCOUNTING
544 bool
545 help
546 Archs need to ensure they use a high enough resolution clock to
547 support irq time accounting and then call enable_sched_clock_irqtime().
548
Gerald Schaefer15626062012-10-08 16:30:04 -0700549config HAVE_ARCH_TRANSPARENT_HUGEPAGE
550 bool
551
Toshi Kani0ddab1d2015-04-14 15:47:20 -0700552config HAVE_ARCH_HUGE_VMAP
553 bool
554
Pavel Emelyanov0f8975e2013-07-03 15:01:20 -0700555config HAVE_ARCH_SOFT_DIRTY
556 bool
557
David Howells786d35d2012-09-28 14:31:03 +0930558config HAVE_MOD_ARCH_SPECIFIC
559 bool
560 help
561 The arch uses struct mod_arch_specific to store data. Many arches
562 just need a simple module loader without arch specific data - those
563 should not enable this.
564
565config MODULES_USE_ELF_RELA
566 bool
567 help
568 Modules only use ELF RELA relocations. Modules with ELF REL
569 relocations will give an error.
570
571config MODULES_USE_ELF_REL
572 bool
573 help
574 Modules only use ELF REL relocations. Modules with ELF RELA
575 relocations will give an error.
576
Rusty Russellb92021b2013-03-15 15:04:17 +1030577config HAVE_UNDERSCORE_SYMBOL_PREFIX
578 bool
579 help
580 Some architectures generate an _ in front of C symbols; things like
581 module loading and assembly files need to know about this.
582
Frederic Weisbeckercc1f0272013-09-24 17:17:47 +0200583config HAVE_IRQ_EXIT_ON_IRQ_STACK
584 bool
585 help
586 Architecture doesn't only execute the irq handler on the irq stack
587 but also irq_exit(). This way we can process softirqs on this irq
588 stack instead of switching to a new one when we call __do_softirq()
589 in the end of an hardirq.
590 This spares a stack switch and improves cache usage on softirq
591 processing.
592
Kirill A. Shutemov235a8f02015-04-14 15:46:17 -0700593config PGTABLE_LEVELS
594 int
595 default 2
596
Kees Cook2b68f6c2015-04-14 15:48:00 -0700597config ARCH_HAS_ELF_RANDOMIZE
598 bool
599 help
600 An architecture supports choosing randomized locations for
601 stack, mmap, brk, and ET_DYN. Defined functions:
602 - arch_mmap_rnd()
Kees Cook204db6e2015-04-14 15:48:12 -0700603 - arch_randomize_brk()
Kees Cook2b68f6c2015-04-14 15:48:00 -0700604
Daniel Cashmand07e2252016-01-14 15:19:53 -0800605config HAVE_ARCH_MMAP_RND_BITS
606 bool
607 help
608 An arch should select this symbol if it supports setting a variable
609 number of bits for use in establishing the base address for mmap
610 allocations, has MMU enabled and provides values for both:
611 - ARCH_MMAP_RND_BITS_MIN
612 - ARCH_MMAP_RND_BITS_MAX
613
Jiri Slaby5f56a5d2016-05-20 17:00:16 -0700614config HAVE_EXIT_THREAD
615 bool
616 help
617 An architecture implements exit_thread.
618
Daniel Cashmand07e2252016-01-14 15:19:53 -0800619config ARCH_MMAP_RND_BITS_MIN
620 int
621
622config ARCH_MMAP_RND_BITS_MAX
623 int
624
625config ARCH_MMAP_RND_BITS_DEFAULT
626 int
627
628config ARCH_MMAP_RND_BITS
629 int "Number of bits to use for ASLR of mmap base address" if EXPERT
630 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
631 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
632 default ARCH_MMAP_RND_BITS_MIN
633 depends on HAVE_ARCH_MMAP_RND_BITS
634 help
635 This value can be used to select the number of bits to use to
636 determine the random offset to the base address of vma regions
637 resulting from mmap allocations. This value will be bounded
638 by the architecture's minimum and maximum supported values.
639
640 This value can be changed after boot using the
641 /proc/sys/vm/mmap_rnd_bits tunable
642
643config HAVE_ARCH_MMAP_RND_COMPAT_BITS
644 bool
645 help
646 An arch should select this symbol if it supports running applications
647 in compatibility mode, supports setting a variable number of bits for
648 use in establishing the base address for mmap allocations, has MMU
649 enabled and provides values for both:
650 - ARCH_MMAP_RND_COMPAT_BITS_MIN
651 - ARCH_MMAP_RND_COMPAT_BITS_MAX
652
653config ARCH_MMAP_RND_COMPAT_BITS_MIN
654 int
655
656config ARCH_MMAP_RND_COMPAT_BITS_MAX
657 int
658
659config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
660 int
661
662config ARCH_MMAP_RND_COMPAT_BITS
663 int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
664 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
665 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
666 default ARCH_MMAP_RND_COMPAT_BITS_MIN
667 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
668 help
669 This value can be used to select the number of bits to use to
670 determine the random offset to the base address of vma regions
671 resulting from mmap allocations for compatible applications This
672 value will be bounded by the architecture's minimum and maximum
673 supported values.
674
675 This value can be changed after boot using the
676 /proc/sys/vm/mmap_rnd_compat_bits tunable
677
Josh Triplett3033f14a2015-06-25 15:01:19 -0700678config HAVE_COPY_THREAD_TLS
679 bool
680 help
681 Architecture provides copy_thread_tls to accept tls argument via
682 normal C parameter passing, rather than extracting the syscall
683 argument from pt_regs.
684
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600685config HAVE_STACK_VALIDATION
686 bool
687 help
688 Architecture supports the 'objtool check' host tool command, which
689 performs compile-time stack metadata validation.
690
George Spelvin468a9422016-05-26 22:11:51 -0400691config HAVE_ARCH_HASH
692 bool
693 default n
694 help
695 If this is set, the architecture provides an <asm/hash.h>
696 file which provides platform-specific implementations of some
697 functions in <linux/hash.h> or fs/namei.c.
698
William Breathitt Gray3a495512016-05-27 18:08:27 -0400699config ISA_BUS_API
700 def_bool ISA
701
Al Virod2125042012-10-23 13:17:59 -0400702#
703# ABI hall of shame
704#
705config CLONE_BACKWARDS
706 bool
707 help
708 Architecture has tls passed as the 4th argument of clone(2),
709 not the 5th one.
710
711config CLONE_BACKWARDS2
712 bool
713 help
714 Architecture has the first two arguments of clone(2) swapped.
715
Michal Simekdfa97712013-08-13 16:00:53 -0700716config CLONE_BACKWARDS3
717 bool
718 help
719 Architecture has tls passed as the 3rd argument of clone(2),
720 not the 5th one.
721
Al Viroeaca6ea2012-11-25 23:12:10 -0500722config ODD_RT_SIGACTION
723 bool
724 help
725 Architecture has unusual rt_sigaction(2) arguments
726
Al Viro0a0e8cd2012-12-25 16:04:12 -0500727config OLD_SIGSUSPEND
728 bool
729 help
730 Architecture has old sigsuspend(2) syscall, of one-argument variety
731
732config OLD_SIGSUSPEND3
733 bool
734 help
735 Even weirder antique ABI - three-argument sigsuspend(2)
736
Al Viro495dfbf2012-12-25 19:09:45 -0500737config OLD_SIGACTION
738 bool
739 help
740 Architecture has old sigaction(2) syscall. Nope, not the same
741 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
742 but fairly different variant of sigaction(2), thanks to OSF/1
743 compatibility...
744
745config COMPAT_OLD_SIGACTION
746 bool
747
Christoph Hellwig0d4a6192016-01-20 15:01:22 -0800748config ARCH_NO_COHERENT_DMA_MMAP
749 bool
750
Zhaoxiu Zengfff7fb02016-05-20 17:03:57 -0700751config CPU_NO_EFFICIENT_FFS
752 def_bool n
753
Andy Lutomirskiba14a192016-08-11 02:35:21 -0700754config HAVE_ARCH_VMAP_STACK
755 def_bool n
756 help
757 An arch should select this symbol if it can support kernel stacks
758 in vmalloc space. This means:
759
760 - vmalloc space must be large enough to hold many kernel stacks.
761 This may rule out many 32-bit architectures.
762
763 - Stacks in vmalloc space need to work reliably. For example, if
764 vmap page tables are created on demand, either this mechanism
765 needs to work while the stack points to a virtual address with
766 unpopulated page tables or arch code (switch_to() and switch_mm(),
767 most likely) needs to ensure that the stack's page table entries
768 are populated before running on a possibly unpopulated stack.
769
770 - If the stack overflows into a guard page, something reasonable
771 should happen. The definition of "reasonable" is flexible, but
772 instantly rebooting without logging anything would be unfriendly.
773
774config VMAP_STACK
775 default y
776 bool "Use a virtually-mapped stack"
777 depends on HAVE_ARCH_VMAP_STACK && !KASAN
778 ---help---
779 Enable this if you want the use virtually-mapped kernel stacks
780 with guard pages. This causes kernel stack overflows to be
781 caught immediately rather than causing difficult-to-diagnose
782 corruption.
783
784 This is presently incompatible with KASAN because KASAN expects
785 the stack to map directly to the KASAN shadow map using a formula
786 that is incorrect if the stack is in vmalloc space.
787
Mao Wenan1a8b6d72017-01-18 08:50:05 +0800788config ARCH_WANT_RELAX_ORDER
789 bool
790
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -0700791source "kernel/gcov/Kconfig"