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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
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05008config OPROFILE
Robert Richterb309a292010-02-26 15:01:23 +01009 tristate "OProfile system profiling"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050010 depends on PROFILING
11 depends on HAVE_OPROFILE
Ingo Molnard69d59f2008-12-12 09:38:57 +010012 select RING_BUFFER
Christian Borntraeger9a5963e2009-09-16 21:56:49 +020013 select RING_BUFFER_ALLOW_SWAP
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050014 help
15 OProfile is a profiling system capable of profiling the
16 whole system, include the kernel, kernel modules, libraries,
17 and applications.
18
19 If unsure, say N.
20
Jason Yeh4d4036e2009-07-08 13:49:38 +020021config OPROFILE_EVENT_MULTIPLEX
22 bool "OProfile multiplexing support (EXPERIMENTAL)"
23 default n
24 depends on OPROFILE && X86
25 help
26 The number of hardware counters is limited. The multiplexing
27 feature enables OProfile to gather more events than counters
28 are provided by the hardware. This is realized by switching
29 between events at an user specified time interval.
30
31 If unsure, say N.
32
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050033config HAVE_OPROFILE
Jan Beulich9ba16082008-10-15 22:01:38 -070034 bool
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050035
Robert Richterdcfce4a2011-10-11 17:11:08 +020036config OPROFILE_NMI_TIMER
37 def_bool y
Anton Blanchardaf9feeb2015-04-09 12:52:55 +100038 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64
Robert Richterdcfce4a2011-10-11 17:11:08 +020039
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050040config KPROBES
41 bool "Kprobes"
Masami Hiramatsu05ed1602010-09-13 19:25:41 +090042 depends on MODULES
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050043 depends on HAVE_KPROBES
Masami Hiramatsu05ed1602010-09-13 19:25:41 +090044 select KALLSYMS
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050045 help
46 Kprobes allows you to trap at almost any kernel address and
47 execute a callback function. register_kprobe() establishes
48 a probepoint and specifies the callback. Kprobes is useful
49 for kernel debugging, non-intrusive instrumentation and testing.
50 If in doubt, say "N".
51
Steven Rostedt45f81b12010-10-29 12:33:43 -040052config JUMP_LABEL
Ingo Molnarc5905af2012-02-24 08:31:31 +010053 bool "Optimize very unlikely/likely branches"
Steven Rostedt45f81b12010-10-29 12:33:43 -040054 depends on HAVE_ARCH_JUMP_LABEL
55 help
Ingo Molnarc5905af2012-02-24 08:31:31 +010056 This option enables a transparent branch optimization that
57 makes certain almost-always-true or almost-always-false branch
58 conditions even cheaper to execute within the kernel.
Steven Rostedt45f81b12010-10-29 12:33:43 -040059
Ingo Molnarc5905af2012-02-24 08:31:31 +010060 Certain performance-sensitive kernel code, such as trace points,
61 scheduler functionality, networking code and KVM have such
62 branches and include support for this optimization technique.
63
64 If it is detected that the compiler has support for "asm goto",
65 the kernel will compile such branches with just a nop
66 instruction. When the condition flag is toggled to true, the
67 nop will be converted to a jump instruction to execute the
68 conditional block of instructions.
69
70 This technique lowers overhead and stress on the branch prediction
71 of the processor and generally makes the kernel faster. The update
72 of the condition is slower, but those are always very rare.
73
74 ( On 32-bit x86, the necessary options added to the compiler
75 flags may increase the size of the kernel slightly. )
Steven Rostedt45f81b12010-10-29 12:33:43 -040076
Peter Zijlstra1987c942015-07-27 18:32:09 +020077config STATIC_KEYS_SELFTEST
78 bool "Static key selftest"
79 depends on JUMP_LABEL
80 help
81 Boot time self-test of the branch patching code.
82
Masami Hiramatsuafd66252010-02-25 08:34:07 -050083config OPTPROBES
Masami Hiramatsu5cc718b2010-03-15 13:00:54 -040084 def_bool y
85 depends on KPROBES && HAVE_OPTPROBES
Masami Hiramatsuafd66252010-02-25 08:34:07 -050086 depends on !PREEMPT
Masami Hiramatsuafd66252010-02-25 08:34:07 -050087
Masami Hiramatsue7dbfe32012-09-28 17:15:20 +090088config KPROBES_ON_FTRACE
89 def_bool y
90 depends on KPROBES && HAVE_KPROBES_ON_FTRACE
91 depends on DYNAMIC_FTRACE_WITH_REGS
92 help
93 If function tracer is enabled and the arch supports full
94 passing of pt_regs to function tracing, then kprobes can
95 optimize on top of function tracing.
96
Srikar Dronamraju2b144492012-02-09 14:56:42 +053097config UPROBES
David A. Long09294e32014-03-07 10:32:22 -050098 def_bool n
Srikar Dronamraju2b144492012-02-09 14:56:42 +053099 help
Ingo Molnar7b2d81d2012-02-17 09:27:41 +0100100 Uprobes is the user-space counterpart to kprobes: they
101 enable instrumentation applications (such as 'perf probe')
102 to establish unintrusive probes in user-space binaries and
103 libraries, by executing handler functions when the probes
104 are hit by user-space applications.
105
106 ( These probes come in the form of single-byte breakpoints,
107 managed by the kernel and kept transparent to the probed
108 application. )
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530109
James Hoganc19fa942012-05-30 11:23:23 +0100110config HAVE_64BIT_ALIGNED_ACCESS
111 def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
112 help
113 Some architectures require 64 bit accesses to be 64 bit
114 aligned, which also requires structs containing 64 bit values
115 to be 64 bit aligned too. This includes some 32 bit
116 architectures which can do 64 bit accesses, as well as 64 bit
117 architectures without unaligned access.
118
119 This symbol should be selected by an architecture if 64 bit
120 accesses are required to be 64 bit aligned in this way even
121 though it is not a 64 bit architecture.
122
123 See Documentation/unaligned-memory-access.txt for more
124 information on the topic of unaligned memory accesses.
125
Johannes Berg58340a02008-07-25 01:45:33 -0700126config HAVE_EFFICIENT_UNALIGNED_ACCESS
Jan Beulich9ba16082008-10-15 22:01:38 -0700127 bool
Johannes Berg58340a02008-07-25 01:45:33 -0700128 help
129 Some architectures are unable to perform unaligned accesses
130 without the use of get_unaligned/put_unaligned. Others are
131 unable to perform such accesses efficiently (e.g. trap on
132 unaligned access and require fixing it up in the exception
133 handler.)
134
135 This symbol should be selected by an architecture if it can
136 perform unaligned accesses efficiently to allow different
137 code paths to be selected for these cases. Some network
138 drivers, for example, could opt to not fix up alignment
139 problems with received packets if doing so would not help
140 much.
141
142 See Documentation/unaligned-memory-access.txt for more
143 information on the topic of unaligned memory accesses.
144
David Woodhousecf66bb92012-12-03 16:25:40 +0000145config ARCH_USE_BUILTIN_BSWAP
146 bool
147 help
148 Modern versions of GCC (since 4.4) have builtin functions
149 for handling byte-swapping. Using these, instead of the old
150 inline assembler that the architecture code provides in the
151 __arch_bswapXX() macros, allows the compiler to see what's
152 happening and offers more opportunity for optimisation. In
153 particular, the compiler will be able to combine the byteswap
154 with a nearby load or store and use load-and-swap or
155 store-and-swap instructions if the architecture has them. It
156 should almost *never* result in code which is worse than the
157 hand-coded assembler in <asm/swab.h>. But just in case it
158 does, the use of the builtins is optional.
159
160 Any architecture with load-and-swap or store-and-swap
161 instructions should set this. And it shouldn't hurt to set it
162 on architectures that don't have such instructions.
163
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -0800164config KRETPROBES
165 def_bool y
166 depends on KPROBES && HAVE_KRETPROBES
167
Avi Kivity7c68af62009-09-19 09:40:22 +0300168config USER_RETURN_NOTIFIER
169 bool
170 depends on HAVE_USER_RETURN_NOTIFIER
171 help
172 Provide a kernel-internal notification when a cpu is about to
173 switch to user mode.
174
Rik van Riel28b2ee22008-07-23 21:27:05 -0700175config HAVE_IOREMAP_PROT
Jan Beulich9ba16082008-10-15 22:01:38 -0700176 bool
Rik van Riel28b2ee22008-07-23 21:27:05 -0700177
Mathieu Desnoyers125e5642008-02-02 15:10:36 -0500178config HAVE_KPROBES
Jan Beulich9ba16082008-10-15 22:01:38 -0700179 bool
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -0800180
181config HAVE_KRETPROBES
Jan Beulich9ba16082008-10-15 22:01:38 -0700182 bool
Arthur Kepner74bc7ce2008-04-29 01:00:30 -0700183
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500184config HAVE_OPTPROBES
185 bool
Cong Wangd314d742012-03-23 15:01:51 -0700186
Masami Hiramatsue7dbfe32012-09-28 17:15:20 +0900187config HAVE_KPROBES_ON_FTRACE
188 bool
189
Cong Wangd314d742012-03-23 15:01:51 -0700190config HAVE_NMI_WATCHDOG
191 bool
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700192#
193# An arch should select this if it provides all these things:
194#
195# task_pt_regs() in asm/processor.h or asm/ptrace.h
196# arch_has_single_step() if there is hardware single-step support
197# arch_has_block_step() if there is hardware block-step support
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700198# asm/syscall.h supplying asm-generic/syscall.h interface
199# linux/regset.h user_regset interfaces
200# CORE_DUMP_USE_REGSET #define'd in linux/elf.h
201# TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit}
202# TIF_NOTIFY_RESUME calls tracehook_notify_resume()
203# signal delivery calls tracehook_signal_handler()
204#
205config HAVE_ARCH_TRACEHOOK
Jan Beulich9ba16082008-10-15 22:01:38 -0700206 bool
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700207
Marek Szyprowskic64be2b2011-12-29 13:09:51 +0100208config HAVE_DMA_CONTIGUOUS
209 bool
210
Thomas Gleixner29d5e042012-04-20 13:05:45 +0000211config GENERIC_SMP_IDLE_THREAD
212 bool
213
Kevin Hilman485cf5d2013-04-24 17:19:13 -0700214config GENERIC_IDLE_POLL_SETUP
215 bool
216
Thomas Gleixnera6359d12012-05-03 09:03:02 +0000217# Select if arch init_task initializer is different to init/init_task.c
218config ARCH_INIT_TASK
Thomas Gleixnera4a2eb42012-05-03 09:02:48 +0000219 bool
220
Thomas Gleixnerf5e10282012-05-05 15:05:48 +0000221# Select if arch has its private alloc_task_struct() function
222config ARCH_TASK_STRUCT_ALLOCATOR
223 bool
224
225# Select if arch has its private alloc_thread_info() function
226config ARCH_THREAD_INFO_ALLOCATOR
227 bool
228
Ingo Molnar5aaeb5c2015-07-17 12:28:12 +0200229# Select if arch wants to size task_struct dynamically via arch_task_struct_size:
230config ARCH_WANTS_DYNAMIC_TASK_STRUCT
231 bool
232
Heiko Carstensf850c30c2010-02-10 17:25:17 +0100233config HAVE_REGS_AND_STACK_ACCESS_API
234 bool
Heiko Carstense01292b2010-02-18 14:25:21 +0100235 help
236 This symbol should be selected by an architecure if it supports
237 the API needed to access registers and stack entries from pt_regs,
238 declared in asm/ptrace.h
239 For example the kprobes-based event tracer needs this API.
Heiko Carstensf850c30c2010-02-10 17:25:17 +0100240
David Brownell9483a572008-07-23 21:26:48 -0700241config HAVE_CLK
Jan Beulich9ba16082008-10-15 22:01:38 -0700242 bool
David Brownell9483a572008-07-23 21:26:48 -0700243 help
244 The <linux/clk.h> calls support software clock gating and
245 thus are a key power management tool on many systems.
246
Joerg Roedel5ee00bd2009-01-09 12:14:24 +0100247config HAVE_DMA_API_DEBUG
248 bool
Heiko Carstens36cd3c92009-04-09 18:48:34 +0200249
K.Prasad62a038d2009-06-01 23:43:33 +0530250config HAVE_HW_BREAKPOINT
251 bool
Frederic Weisbecker99e8c5a2009-12-17 01:33:54 +0100252 depends on PERF_EVENTS
K.Prasad62a038d2009-06-01 23:43:33 +0530253
Frederic Weisbecker01027522010-04-11 18:55:56 +0200254config HAVE_MIXED_BREAKPOINTS_REGS
255 bool
256 depends on HAVE_HW_BREAKPOINT
257 help
258 Depending on the arch implementation of hardware breakpoints,
259 some of them have separate registers for data and instruction
260 breakpoints addresses, others have mixed registers to store
261 them but define the access type in a control register.
262 Select this option if your arch implements breakpoints under the
263 latter fashion.
264
Avi Kivity7c68af62009-09-19 09:40:22 +0300265config HAVE_USER_RETURN_NOTIFIER
266 bool
Ingo Molnara1922ed2009-09-07 08:19:51 +0200267
Frederic Weisbeckerc01d4322010-05-15 22:57:48 +0200268config HAVE_PERF_EVENTS_NMI
269 bool
Frederic Weisbecker23637d42010-05-15 23:15:20 +0200270 help
271 System hardware can generate an NMI using the perf event
272 subsystem. Also has support for calculating CPU cycle events
273 to determine how many clock cycles in a given period.
Frederic Weisbeckerc01d4322010-05-15 22:57:48 +0200274
Jiri Olsac5e63192012-08-07 15:20:36 +0200275config HAVE_PERF_REGS
276 bool
277 help
278 Support selective register dumps for perf events. This includes
279 bit-mapping of each registers and a unique architecture id.
280
Jiri Olsac5ebced2012-08-07 15:20:40 +0200281config HAVE_PERF_USER_STACK_DUMP
282 bool
283 help
284 Support user stack dumps for perf event samples. This needs
285 access to the user stack pointer which is not unified across
286 architectures.
287
Jason Baronbf5438fc2010-09-17 11:09:00 -0400288config HAVE_ARCH_JUMP_LABEL
289 bool
290
Peter Zijlstra26723912011-05-24 17:12:00 -0700291config HAVE_RCU_TABLE_FREE
292 bool
293
Huang Yingdf013ff2011-07-13 13:14:22 +0800294config ARCH_HAVE_NMI_SAFE_CMPXCHG
295 bool
296
Heiko Carstens43570fd2012-01-12 17:17:27 -0800297config HAVE_ALIGNED_STRUCT_PAGE
298 bool
299 help
300 This makes sure that struct pages are double word aligned and that
301 e.g. the SLUB allocator can perform double word atomic operations
302 on a struct page for better performance. However selecting this
303 might increase the size of a struct page by a word.
304
Heiko Carstens41561532012-01-12 17:17:30 -0800305config HAVE_CMPXCHG_LOCAL
306 bool
307
Heiko Carstens25654092012-01-12 17:17:33 -0800308config HAVE_CMPXCHG_DOUBLE
309 bool
310
Will Deaconc1d7e012012-07-30 14:42:46 -0700311config ARCH_WANT_IPC_PARSE_VERSION
312 bool
313
314config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
315 bool
316
Chris Metcalf48b25c42012-03-15 13:13:38 -0400317config ARCH_WANT_OLD_COMPAT_IPC
Will Deaconc1d7e012012-07-30 14:42:46 -0700318 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
Chris Metcalf48b25c42012-03-15 13:13:38 -0400319 bool
320
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500321config HAVE_ARCH_SECCOMP_FILTER
322 bool
323 help
Will Drewryfb0fadf2012-04-12 16:48:02 -0500324 An arch should select this symbol if it provides all of these things:
Will Drewrybb6ea432012-04-12 16:48:01 -0500325 - syscall_get_arch()
326 - syscall_get_arguments()
327 - syscall_rollback()
328 - syscall_set_return_value()
Will Drewryfb0fadf2012-04-12 16:48:02 -0500329 - SIGSYS siginfo_t support
330 - secure_computing is called from a ptrace_event()-safe context
331 - secure_computing return value is checked and a return value of -1
332 results in the system call being skipped immediately.
Kees Cook48dc92b2014-06-25 16:08:24 -0700333 - seccomp syscall wired up
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500334
Andy Lutomirskiff27f382014-07-21 18:49:17 -0700335 For best performance, an arch should use seccomp_phase1 and
336 seccomp_phase2 directly. It should call seccomp_phase1 for all
337 syscalls if TIF_SECCOMP is set, but seccomp_phase1 does not
338 need to be called from a ptrace-safe context. It must then
339 call seccomp_phase2 if seccomp_phase1 returns anything other
340 than SECCOMP_PHASE1_OK or SECCOMP_PHASE1_SKIP.
341
342 As an additional optimization, an arch may provide seccomp_data
343 directly to seccomp_phase1; this avoids multiple calls
344 to the syscall_xyz helpers for every syscall.
345
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500346config SECCOMP_FILTER
347 def_bool y
348 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
349 help
350 Enable tasks to build secure computing environments defined
351 in terms of Berkeley Packet Filter programs which implement
352 task-defined system call filtering polices.
353
354 See Documentation/prctl/seccomp_filter.txt for details.
355
Kees Cook19952a92013-12-19 11:35:58 -0800356config HAVE_CC_STACKPROTECTOR
357 bool
358 help
359 An arch should select this symbol if:
360 - its compiler supports the -fstack-protector option
361 - it has implemented a stack canary (e.g. __stack_chk_guard)
362
363config CC_STACKPROTECTOR
Kees Cook87796572013-12-19 11:35:59 -0800364 def_bool n
Kees Cook19952a92013-12-19 11:35:58 -0800365 help
Kees Cook87796572013-12-19 11:35:59 -0800366 Set when a stack-protector mode is enabled, so that the build
367 can enable kernel-side support for the GCC feature.
368
369choice
370 prompt "Stack Protector buffer overflow detection"
371 depends on HAVE_CC_STACKPROTECTOR
372 default CC_STACKPROTECTOR_NONE
373 help
374 This option turns on the "stack-protector" GCC feature. This
Kees Cook19952a92013-12-19 11:35:58 -0800375 feature puts, at the beginning of functions, a canary value on
376 the stack just before the return address, and validates
377 the value just before actually returning. Stack based buffer
378 overflows (that need to overwrite this return address) now also
379 overwrite the canary, which gets detected and the attack is then
380 neutralized via a kernel panic.
381
Kees Cook87796572013-12-19 11:35:59 -0800382config CC_STACKPROTECTOR_NONE
383 bool "None"
384 help
385 Disable "stack-protector" GCC feature.
386
387config CC_STACKPROTECTOR_REGULAR
388 bool "Regular"
389 select CC_STACKPROTECTOR
390 help
391 Functions will have the stack-protector canary logic added if they
392 have an 8-byte or larger character array on the stack.
393
Kees Cook19952a92013-12-19 11:35:58 -0800394 This feature requires gcc version 4.2 or above, or a distribution
Kees Cook87796572013-12-19 11:35:59 -0800395 gcc with the feature backported ("-fstack-protector").
396
397 On an x86 "defconfig" build, this feature adds canary checks to
398 about 3% of all kernel functions, which increases kernel code size
399 by about 0.3%.
400
401config CC_STACKPROTECTOR_STRONG
402 bool "Strong"
403 select CC_STACKPROTECTOR
404 help
405 Functions will have the stack-protector canary logic added in any
406 of the following conditions:
407
408 - local variable's address used as part of the right hand side of an
409 assignment or function argument
410 - local variable is an array (or union containing an array),
411 regardless of array type or length
412 - uses register local variables
413
414 This feature requires gcc version 4.9 or above, or a distribution
415 gcc with the feature backported ("-fstack-protector-strong").
416
417 On an x86 "defconfig" build, this feature adds canary checks to
418 about 20% of all kernel functions, which increases the kernel code
419 size by about 2%.
420
421endchoice
Kees Cook19952a92013-12-19 11:35:58 -0800422
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100423config HAVE_CONTEXT_TRACKING
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200424 bool
425 help
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100426 Provide kernel/user boundaries probes necessary for subsystems
427 that need it, such as userspace RCU extended quiescent state.
428 Syscalls need to be wrapped inside user_exit()-user_enter() through
429 the slow path using TIF_NOHZ flag. Exceptions handlers must be
430 wrapped as well. Irqs are already protected inside
431 rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on
432 irq exit still need to be protected.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200433
Frederic Weisbeckerb9527412012-06-16 15:39:34 +0200434config HAVE_VIRT_CPU_ACCOUNTING
435 bool
436
Kevin Hilman554b0002013-09-16 15:28:21 -0700437config HAVE_VIRT_CPU_ACCOUNTING_GEN
438 bool
439 default y if 64BIT
440 help
441 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
442 Before enabling this option, arch code must be audited
443 to ensure there are no races in concurrent read/write of
444 cputime_t. For example, reading/writing 64-bit cputime_t on
445 some 32-bit arches may require multiple accesses, so proper
446 locking is needed to protect against concurrent accesses.
447
448
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200449config HAVE_IRQ_TIME_ACCOUNTING
450 bool
451 help
452 Archs need to ensure they use a high enough resolution clock to
453 support irq time accounting and then call enable_sched_clock_irqtime().
454
Gerald Schaefer15626062012-10-08 16:30:04 -0700455config HAVE_ARCH_TRANSPARENT_HUGEPAGE
456 bool
457
Toshi Kani0ddab1d2015-04-14 15:47:20 -0700458config HAVE_ARCH_HUGE_VMAP
459 bool
460
Pavel Emelyanov0f8975e2013-07-03 15:01:20 -0700461config HAVE_ARCH_SOFT_DIRTY
462 bool
463
David Howells786d35d2012-09-28 14:31:03 +0930464config HAVE_MOD_ARCH_SPECIFIC
465 bool
466 help
467 The arch uses struct mod_arch_specific to store data. Many arches
468 just need a simple module loader without arch specific data - those
469 should not enable this.
470
471config MODULES_USE_ELF_RELA
472 bool
473 help
474 Modules only use ELF RELA relocations. Modules with ELF REL
475 relocations will give an error.
476
477config MODULES_USE_ELF_REL
478 bool
479 help
480 Modules only use ELF REL relocations. Modules with ELF RELA
481 relocations will give an error.
482
Rusty Russellb92021b2013-03-15 15:04:17 +1030483config HAVE_UNDERSCORE_SYMBOL_PREFIX
484 bool
485 help
486 Some architectures generate an _ in front of C symbols; things like
487 module loading and assembly files need to know about this.
488
Frederic Weisbeckercc1f0272013-09-24 17:17:47 +0200489config HAVE_IRQ_EXIT_ON_IRQ_STACK
490 bool
491 help
492 Architecture doesn't only execute the irq handler on the irq stack
493 but also irq_exit(). This way we can process softirqs on this irq
494 stack instead of switching to a new one when we call __do_softirq()
495 in the end of an hardirq.
496 This spares a stack switch and improves cache usage on softirq
497 processing.
498
Kirill A. Shutemov235a8f02015-04-14 15:46:17 -0700499config PGTABLE_LEVELS
500 int
501 default 2
502
Kees Cook2b68f6c2015-04-14 15:48:00 -0700503config ARCH_HAS_ELF_RANDOMIZE
504 bool
505 help
506 An architecture supports choosing randomized locations for
507 stack, mmap, brk, and ET_DYN. Defined functions:
508 - arch_mmap_rnd()
Kees Cook204db6e2015-04-14 15:48:12 -0700509 - arch_randomize_brk()
Kees Cook2b68f6c2015-04-14 15:48:00 -0700510
Daniel Cashmand07e2252016-01-14 15:19:53 -0800511config HAVE_ARCH_MMAP_RND_BITS
512 bool
513 help
514 An arch should select this symbol if it supports setting a variable
515 number of bits for use in establishing the base address for mmap
516 allocations, has MMU enabled and provides values for both:
517 - ARCH_MMAP_RND_BITS_MIN
518 - ARCH_MMAP_RND_BITS_MAX
519
Jiri Slaby5f56a5d2016-05-20 17:00:16 -0700520config HAVE_EXIT_THREAD
521 bool
522 help
523 An architecture implements exit_thread.
524
Daniel Cashmand07e2252016-01-14 15:19:53 -0800525config ARCH_MMAP_RND_BITS_MIN
526 int
527
528config ARCH_MMAP_RND_BITS_MAX
529 int
530
531config ARCH_MMAP_RND_BITS_DEFAULT
532 int
533
534config ARCH_MMAP_RND_BITS
535 int "Number of bits to use for ASLR of mmap base address" if EXPERT
536 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
537 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
538 default ARCH_MMAP_RND_BITS_MIN
539 depends on HAVE_ARCH_MMAP_RND_BITS
540 help
541 This value can be used to select the number of bits to use to
542 determine the random offset to the base address of vma regions
543 resulting from mmap allocations. This value will be bounded
544 by the architecture's minimum and maximum supported values.
545
546 This value can be changed after boot using the
547 /proc/sys/vm/mmap_rnd_bits tunable
548
549config HAVE_ARCH_MMAP_RND_COMPAT_BITS
550 bool
551 help
552 An arch should select this symbol if it supports running applications
553 in compatibility mode, supports setting a variable number of bits for
554 use in establishing the base address for mmap allocations, has MMU
555 enabled and provides values for both:
556 - ARCH_MMAP_RND_COMPAT_BITS_MIN
557 - ARCH_MMAP_RND_COMPAT_BITS_MAX
558
559config ARCH_MMAP_RND_COMPAT_BITS_MIN
560 int
561
562config ARCH_MMAP_RND_COMPAT_BITS_MAX
563 int
564
565config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
566 int
567
568config ARCH_MMAP_RND_COMPAT_BITS
569 int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
570 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
571 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
572 default ARCH_MMAP_RND_COMPAT_BITS_MIN
573 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
574 help
575 This value can be used to select the number of bits to use to
576 determine the random offset to the base address of vma regions
577 resulting from mmap allocations for compatible applications This
578 value will be bounded by the architecture's minimum and maximum
579 supported values.
580
581 This value can be changed after boot using the
582 /proc/sys/vm/mmap_rnd_compat_bits tunable
583
Josh Triplett3033f14a2015-06-25 15:01:19 -0700584config HAVE_COPY_THREAD_TLS
585 bool
586 help
587 Architecture provides copy_thread_tls to accept tls argument via
588 normal C parameter passing, rather than extracting the syscall
589 argument from pt_regs.
590
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600591config HAVE_STACK_VALIDATION
592 bool
593 help
594 Architecture supports the 'objtool check' host tool command, which
595 performs compile-time stack metadata validation.
596
Al Virod2125042012-10-23 13:17:59 -0400597#
598# ABI hall of shame
599#
600config CLONE_BACKWARDS
601 bool
602 help
603 Architecture has tls passed as the 4th argument of clone(2),
604 not the 5th one.
605
606config CLONE_BACKWARDS2
607 bool
608 help
609 Architecture has the first two arguments of clone(2) swapped.
610
Michal Simekdfa97712013-08-13 16:00:53 -0700611config CLONE_BACKWARDS3
612 bool
613 help
614 Architecture has tls passed as the 3rd argument of clone(2),
615 not the 5th one.
616
Al Viroeaca6ea2012-11-25 23:12:10 -0500617config ODD_RT_SIGACTION
618 bool
619 help
620 Architecture has unusual rt_sigaction(2) arguments
621
Al Viro0a0e8cd2012-12-25 16:04:12 -0500622config OLD_SIGSUSPEND
623 bool
624 help
625 Architecture has old sigsuspend(2) syscall, of one-argument variety
626
627config OLD_SIGSUSPEND3
628 bool
629 help
630 Even weirder antique ABI - three-argument sigsuspend(2)
631
Al Viro495dfbf2012-12-25 19:09:45 -0500632config OLD_SIGACTION
633 bool
634 help
635 Architecture has old sigaction(2) syscall. Nope, not the same
636 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
637 but fairly different variant of sigaction(2), thanks to OSF/1
638 compatibility...
639
640config COMPAT_OLD_SIGACTION
641 bool
642
Christoph Hellwig0d4a6192016-01-20 15:01:22 -0800643config ARCH_NO_COHERENT_DMA_MMAP
644 bool
645
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -0700646source "kernel/gcov/Kconfig"