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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
5config OPROFILE
Robert Richterb309a292010-02-26 15:01:23 +01006 tristate "OProfile system profiling"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05007 depends on PROFILING
8 depends on HAVE_OPROFILE
Ingo Molnard69d59f2008-12-12 09:38:57 +01009 select RING_BUFFER
Christian Borntraeger9a5963e2009-09-16 21:56:49 +020010 select RING_BUFFER_ALLOW_SWAP
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050011 help
12 OProfile is a profiling system capable of profiling the
13 whole system, include the kernel, kernel modules, libraries,
14 and applications.
15
16 If unsure, say N.
17
Jason Yeh4d4036e2009-07-08 13:49:38 +020018config OPROFILE_EVENT_MULTIPLEX
19 bool "OProfile multiplexing support (EXPERIMENTAL)"
20 default n
21 depends on OPROFILE && X86
22 help
23 The number of hardware counters is limited. The multiplexing
24 feature enables OProfile to gather more events than counters
25 are provided by the hardware. This is realized by switching
26 between events at an user specified time interval.
27
28 If unsure, say N.
29
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050030config HAVE_OPROFILE
Jan Beulich9ba16082008-10-15 22:01:38 -070031 bool
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050032
Robert Richterdcfce4a2011-10-11 17:11:08 +020033config OPROFILE_NMI_TIMER
34 def_bool y
Anton Blanchardaf9feeb2015-04-09 12:52:55 +100035 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64
Robert Richterdcfce4a2011-10-11 17:11:08 +020036
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050037config KPROBES
38 bool "Kprobes"
Masami Hiramatsu05ed1602010-09-13 19:25:41 +090039 depends on MODULES
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050040 depends on HAVE_KPROBES
Masami Hiramatsu05ed1602010-09-13 19:25:41 +090041 select KALLSYMS
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050042 help
43 Kprobes allows you to trap at almost any kernel address and
44 execute a callback function. register_kprobe() establishes
45 a probepoint and specifies the callback. Kprobes is useful
46 for kernel debugging, non-intrusive instrumentation and testing.
47 If in doubt, say "N".
48
Steven Rostedt45f81b12010-10-29 12:33:43 -040049config JUMP_LABEL
Ingo Molnarc5905af2012-02-24 08:31:31 +010050 bool "Optimize very unlikely/likely branches"
Steven Rostedt45f81b12010-10-29 12:33:43 -040051 depends on HAVE_ARCH_JUMP_LABEL
52 help
Ingo Molnarc5905af2012-02-24 08:31:31 +010053 This option enables a transparent branch optimization that
54 makes certain almost-always-true or almost-always-false branch
55 conditions even cheaper to execute within the kernel.
Steven Rostedt45f81b12010-10-29 12:33:43 -040056
Ingo Molnarc5905af2012-02-24 08:31:31 +010057 Certain performance-sensitive kernel code, such as trace points,
58 scheduler functionality, networking code and KVM have such
59 branches and include support for this optimization technique.
60
61 If it is detected that the compiler has support for "asm goto",
62 the kernel will compile such branches with just a nop
63 instruction. When the condition flag is toggled to true, the
64 nop will be converted to a jump instruction to execute the
65 conditional block of instructions.
66
67 This technique lowers overhead and stress on the branch prediction
68 of the processor and generally makes the kernel faster. The update
69 of the condition is slower, but those are always very rare.
70
71 ( On 32-bit x86, the necessary options added to the compiler
72 flags may increase the size of the kernel slightly. )
Steven Rostedt45f81b12010-10-29 12:33:43 -040073
Masami Hiramatsuafd66252010-02-25 08:34:07 -050074config OPTPROBES
Masami Hiramatsu5cc718b2010-03-15 13:00:54 -040075 def_bool y
76 depends on KPROBES && HAVE_OPTPROBES
Masami Hiramatsuafd66252010-02-25 08:34:07 -050077 depends on !PREEMPT
Masami Hiramatsuafd66252010-02-25 08:34:07 -050078
Masami Hiramatsue7dbfe32012-09-28 17:15:20 +090079config KPROBES_ON_FTRACE
80 def_bool y
81 depends on KPROBES && HAVE_KPROBES_ON_FTRACE
82 depends on DYNAMIC_FTRACE_WITH_REGS
83 help
84 If function tracer is enabled and the arch supports full
85 passing of pt_regs to function tracing, then kprobes can
86 optimize on top of function tracing.
87
Srikar Dronamraju2b144492012-02-09 14:56:42 +053088config UPROBES
David A. Long09294e32014-03-07 10:32:22 -050089 def_bool n
Oleg Nesterov22b361d2012-12-17 16:01:39 -080090 select PERCPU_RWSEM
Srikar Dronamraju2b144492012-02-09 14:56:42 +053091 help
Ingo Molnar7b2d81d2012-02-17 09:27:41 +010092 Uprobes is the user-space counterpart to kprobes: they
93 enable instrumentation applications (such as 'perf probe')
94 to establish unintrusive probes in user-space binaries and
95 libraries, by executing handler functions when the probes
96 are hit by user-space applications.
97
98 ( These probes come in the form of single-byte breakpoints,
99 managed by the kernel and kept transparent to the probed
100 application. )
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530101
James Hoganc19fa942012-05-30 11:23:23 +0100102config HAVE_64BIT_ALIGNED_ACCESS
103 def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
104 help
105 Some architectures require 64 bit accesses to be 64 bit
106 aligned, which also requires structs containing 64 bit values
107 to be 64 bit aligned too. This includes some 32 bit
108 architectures which can do 64 bit accesses, as well as 64 bit
109 architectures without unaligned access.
110
111 This symbol should be selected by an architecture if 64 bit
112 accesses are required to be 64 bit aligned in this way even
113 though it is not a 64 bit architecture.
114
115 See Documentation/unaligned-memory-access.txt for more
116 information on the topic of unaligned memory accesses.
117
Johannes Berg58340a02008-07-25 01:45:33 -0700118config HAVE_EFFICIENT_UNALIGNED_ACCESS
Jan Beulich9ba16082008-10-15 22:01:38 -0700119 bool
Johannes Berg58340a02008-07-25 01:45:33 -0700120 help
121 Some architectures are unable to perform unaligned accesses
122 without the use of get_unaligned/put_unaligned. Others are
123 unable to perform such accesses efficiently (e.g. trap on
124 unaligned access and require fixing it up in the exception
125 handler.)
126
127 This symbol should be selected by an architecture if it can
128 perform unaligned accesses efficiently to allow different
129 code paths to be selected for these cases. Some network
130 drivers, for example, could opt to not fix up alignment
131 problems with received packets if doing so would not help
132 much.
133
134 See Documentation/unaligned-memory-access.txt for more
135 information on the topic of unaligned memory accesses.
136
David Woodhousecf66bb92012-12-03 16:25:40 +0000137config ARCH_USE_BUILTIN_BSWAP
138 bool
139 help
140 Modern versions of GCC (since 4.4) have builtin functions
141 for handling byte-swapping. Using these, instead of the old
142 inline assembler that the architecture code provides in the
143 __arch_bswapXX() macros, allows the compiler to see what's
144 happening and offers more opportunity for optimisation. In
145 particular, the compiler will be able to combine the byteswap
146 with a nearby load or store and use load-and-swap or
147 store-and-swap instructions if the architecture has them. It
148 should almost *never* result in code which is worse than the
149 hand-coded assembler in <asm/swab.h>. But just in case it
150 does, the use of the builtins is optional.
151
152 Any architecture with load-and-swap or store-and-swap
153 instructions should set this. And it shouldn't hurt to set it
154 on architectures that don't have such instructions.
155
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -0800156config KRETPROBES
157 def_bool y
158 depends on KPROBES && HAVE_KRETPROBES
159
Avi Kivity7c68af62009-09-19 09:40:22 +0300160config USER_RETURN_NOTIFIER
161 bool
162 depends on HAVE_USER_RETURN_NOTIFIER
163 help
164 Provide a kernel-internal notification when a cpu is about to
165 switch to user mode.
166
Rik van Riel28b2ee22008-07-23 21:27:05 -0700167config HAVE_IOREMAP_PROT
Jan Beulich9ba16082008-10-15 22:01:38 -0700168 bool
Rik van Riel28b2ee22008-07-23 21:27:05 -0700169
Mathieu Desnoyers125e5642008-02-02 15:10:36 -0500170config HAVE_KPROBES
Jan Beulich9ba16082008-10-15 22:01:38 -0700171 bool
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -0800172
173config HAVE_KRETPROBES
Jan Beulich9ba16082008-10-15 22:01:38 -0700174 bool
Arthur Kepner74bc7ce2008-04-29 01:00:30 -0700175
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500176config HAVE_OPTPROBES
177 bool
Cong Wangd314d742012-03-23 15:01:51 -0700178
Masami Hiramatsue7dbfe32012-09-28 17:15:20 +0900179config HAVE_KPROBES_ON_FTRACE
180 bool
181
Cong Wangd314d742012-03-23 15:01:51 -0700182config HAVE_NMI_WATCHDOG
183 bool
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700184#
185# An arch should select this if it provides all these things:
186#
187# task_pt_regs() in asm/processor.h or asm/ptrace.h
188# arch_has_single_step() if there is hardware single-step support
189# arch_has_block_step() if there is hardware block-step support
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700190# asm/syscall.h supplying asm-generic/syscall.h interface
191# linux/regset.h user_regset interfaces
192# CORE_DUMP_USE_REGSET #define'd in linux/elf.h
193# TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit}
194# TIF_NOTIFY_RESUME calls tracehook_notify_resume()
195# signal delivery calls tracehook_signal_handler()
196#
197config HAVE_ARCH_TRACEHOOK
Jan Beulich9ba16082008-10-15 22:01:38 -0700198 bool
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700199
Arthur Kepner74bc7ce2008-04-29 01:00:30 -0700200config HAVE_DMA_ATTRS
Jan Beulich9ba16082008-10-15 22:01:38 -0700201 bool
Jens Axboe3d442232008-06-26 11:21:34 +0200202
Marek Szyprowskic64be2b2011-12-29 13:09:51 +0100203config HAVE_DMA_CONTIGUOUS
204 bool
205
Thomas Gleixner29d5e042012-04-20 13:05:45 +0000206config GENERIC_SMP_IDLE_THREAD
207 bool
208
Kevin Hilman485cf5d2013-04-24 17:19:13 -0700209config GENERIC_IDLE_POLL_SETUP
210 bool
211
Thomas Gleixnera6359d12012-05-03 09:03:02 +0000212# Select if arch init_task initializer is different to init/init_task.c
213config ARCH_INIT_TASK
Thomas Gleixnera4a2eb42012-05-03 09:02:48 +0000214 bool
215
Thomas Gleixnerf5e10282012-05-05 15:05:48 +0000216# Select if arch has its private alloc_task_struct() function
217config ARCH_TASK_STRUCT_ALLOCATOR
218 bool
219
220# Select if arch has its private alloc_thread_info() function
221config ARCH_THREAD_INFO_ALLOCATOR
222 bool
223
Heiko Carstensf850c30c2010-02-10 17:25:17 +0100224config HAVE_REGS_AND_STACK_ACCESS_API
225 bool
Heiko Carstense01292b2010-02-18 14:25:21 +0100226 help
227 This symbol should be selected by an architecure if it supports
228 the API needed to access registers and stack entries from pt_regs,
229 declared in asm/ptrace.h
230 For example the kprobes-based event tracer needs this API.
Heiko Carstensf850c30c2010-02-10 17:25:17 +0100231
David Brownell9483a572008-07-23 21:26:48 -0700232config HAVE_CLK
Jan Beulich9ba16082008-10-15 22:01:38 -0700233 bool
David Brownell9483a572008-07-23 21:26:48 -0700234 help
235 The <linux/clk.h> calls support software clock gating and
236 thus are a key power management tool on many systems.
237
Joerg Roedel5ee00bd2009-01-09 12:14:24 +0100238config HAVE_DMA_API_DEBUG
239 bool
Heiko Carstens36cd3c92009-04-09 18:48:34 +0200240
K.Prasad62a038d2009-06-01 23:43:33 +0530241config HAVE_HW_BREAKPOINT
242 bool
Frederic Weisbecker99e8c5a2009-12-17 01:33:54 +0100243 depends on PERF_EVENTS
K.Prasad62a038d2009-06-01 23:43:33 +0530244
Frederic Weisbecker01027522010-04-11 18:55:56 +0200245config HAVE_MIXED_BREAKPOINTS_REGS
246 bool
247 depends on HAVE_HW_BREAKPOINT
248 help
249 Depending on the arch implementation of hardware breakpoints,
250 some of them have separate registers for data and instruction
251 breakpoints addresses, others have mixed registers to store
252 them but define the access type in a control register.
253 Select this option if your arch implements breakpoints under the
254 latter fashion.
255
Avi Kivity7c68af62009-09-19 09:40:22 +0300256config HAVE_USER_RETURN_NOTIFIER
257 bool
Ingo Molnara1922ed2009-09-07 08:19:51 +0200258
Frederic Weisbeckerc01d4322010-05-15 22:57:48 +0200259config HAVE_PERF_EVENTS_NMI
260 bool
Frederic Weisbecker23637d42010-05-15 23:15:20 +0200261 help
262 System hardware can generate an NMI using the perf event
263 subsystem. Also has support for calculating CPU cycle events
264 to determine how many clock cycles in a given period.
Frederic Weisbeckerc01d4322010-05-15 22:57:48 +0200265
Jiri Olsac5e63192012-08-07 15:20:36 +0200266config HAVE_PERF_REGS
267 bool
268 help
269 Support selective register dumps for perf events. This includes
270 bit-mapping of each registers and a unique architecture id.
271
Jiri Olsac5ebced2012-08-07 15:20:40 +0200272config HAVE_PERF_USER_STACK_DUMP
273 bool
274 help
275 Support user stack dumps for perf event samples. This needs
276 access to the user stack pointer which is not unified across
277 architectures.
278
Jason Baronbf5438fc2010-09-17 11:09:00 -0400279config HAVE_ARCH_JUMP_LABEL
280 bool
281
Peter Zijlstra26723912011-05-24 17:12:00 -0700282config HAVE_RCU_TABLE_FREE
283 bool
284
Huang Yingdf013ff2011-07-13 13:14:22 +0800285config ARCH_HAVE_NMI_SAFE_CMPXCHG
286 bool
287
Heiko Carstens43570fd2012-01-12 17:17:27 -0800288config HAVE_ALIGNED_STRUCT_PAGE
289 bool
290 help
291 This makes sure that struct pages are double word aligned and that
292 e.g. the SLUB allocator can perform double word atomic operations
293 on a struct page for better performance. However selecting this
294 might increase the size of a struct page by a word.
295
Heiko Carstens41561532012-01-12 17:17:30 -0800296config HAVE_CMPXCHG_LOCAL
297 bool
298
Heiko Carstens25654092012-01-12 17:17:33 -0800299config HAVE_CMPXCHG_DOUBLE
300 bool
301
Will Deaconc1d7e012012-07-30 14:42:46 -0700302config ARCH_WANT_IPC_PARSE_VERSION
303 bool
304
305config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
306 bool
307
Chris Metcalf48b25c42012-03-15 13:13:38 -0400308config ARCH_WANT_OLD_COMPAT_IPC
Will Deaconc1d7e012012-07-30 14:42:46 -0700309 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
Chris Metcalf48b25c42012-03-15 13:13:38 -0400310 bool
311
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500312config HAVE_ARCH_SECCOMP_FILTER
313 bool
314 help
Will Drewryfb0fadf2012-04-12 16:48:02 -0500315 An arch should select this symbol if it provides all of these things:
Will Drewrybb6ea432012-04-12 16:48:01 -0500316 - syscall_get_arch()
317 - syscall_get_arguments()
318 - syscall_rollback()
319 - syscall_set_return_value()
Will Drewryfb0fadf2012-04-12 16:48:02 -0500320 - SIGSYS siginfo_t support
321 - secure_computing is called from a ptrace_event()-safe context
322 - secure_computing return value is checked and a return value of -1
323 results in the system call being skipped immediately.
Kees Cook48dc92b2014-06-25 16:08:24 -0700324 - seccomp syscall wired up
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500325
Andy Lutomirskiff27f382014-07-21 18:49:17 -0700326 For best performance, an arch should use seccomp_phase1 and
327 seccomp_phase2 directly. It should call seccomp_phase1 for all
328 syscalls if TIF_SECCOMP is set, but seccomp_phase1 does not
329 need to be called from a ptrace-safe context. It must then
330 call seccomp_phase2 if seccomp_phase1 returns anything other
331 than SECCOMP_PHASE1_OK or SECCOMP_PHASE1_SKIP.
332
333 As an additional optimization, an arch may provide seccomp_data
334 directly to seccomp_phase1; this avoids multiple calls
335 to the syscall_xyz helpers for every syscall.
336
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500337config SECCOMP_FILTER
338 def_bool y
339 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
340 help
341 Enable tasks to build secure computing environments defined
342 in terms of Berkeley Packet Filter programs which implement
343 task-defined system call filtering polices.
344
345 See Documentation/prctl/seccomp_filter.txt for details.
346
Kees Cook19952a92013-12-19 11:35:58 -0800347config HAVE_CC_STACKPROTECTOR
348 bool
349 help
350 An arch should select this symbol if:
351 - its compiler supports the -fstack-protector option
352 - it has implemented a stack canary (e.g. __stack_chk_guard)
353
354config CC_STACKPROTECTOR
Kees Cook87796572013-12-19 11:35:59 -0800355 def_bool n
Kees Cook19952a92013-12-19 11:35:58 -0800356 help
Kees Cook87796572013-12-19 11:35:59 -0800357 Set when a stack-protector mode is enabled, so that the build
358 can enable kernel-side support for the GCC feature.
359
360choice
361 prompt "Stack Protector buffer overflow detection"
362 depends on HAVE_CC_STACKPROTECTOR
363 default CC_STACKPROTECTOR_NONE
364 help
365 This option turns on the "stack-protector" GCC feature. This
Kees Cook19952a92013-12-19 11:35:58 -0800366 feature puts, at the beginning of functions, a canary value on
367 the stack just before the return address, and validates
368 the value just before actually returning. Stack based buffer
369 overflows (that need to overwrite this return address) now also
370 overwrite the canary, which gets detected and the attack is then
371 neutralized via a kernel panic.
372
Kees Cook87796572013-12-19 11:35:59 -0800373config CC_STACKPROTECTOR_NONE
374 bool "None"
375 help
376 Disable "stack-protector" GCC feature.
377
378config CC_STACKPROTECTOR_REGULAR
379 bool "Regular"
380 select CC_STACKPROTECTOR
381 help
382 Functions will have the stack-protector canary logic added if they
383 have an 8-byte or larger character array on the stack.
384
Kees Cook19952a92013-12-19 11:35:58 -0800385 This feature requires gcc version 4.2 or above, or a distribution
Kees Cook87796572013-12-19 11:35:59 -0800386 gcc with the feature backported ("-fstack-protector").
387
388 On an x86 "defconfig" build, this feature adds canary checks to
389 about 3% of all kernel functions, which increases kernel code size
390 by about 0.3%.
391
392config CC_STACKPROTECTOR_STRONG
393 bool "Strong"
394 select CC_STACKPROTECTOR
395 help
396 Functions will have the stack-protector canary logic added in any
397 of the following conditions:
398
399 - local variable's address used as part of the right hand side of an
400 assignment or function argument
401 - local variable is an array (or union containing an array),
402 regardless of array type or length
403 - uses register local variables
404
405 This feature requires gcc version 4.9 or above, or a distribution
406 gcc with the feature backported ("-fstack-protector-strong").
407
408 On an x86 "defconfig" build, this feature adds canary checks to
409 about 20% of all kernel functions, which increases the kernel code
410 size by about 2%.
411
412endchoice
Kees Cook19952a92013-12-19 11:35:58 -0800413
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100414config HAVE_CONTEXT_TRACKING
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200415 bool
416 help
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100417 Provide kernel/user boundaries probes necessary for subsystems
418 that need it, such as userspace RCU extended quiescent state.
419 Syscalls need to be wrapped inside user_exit()-user_enter() through
420 the slow path using TIF_NOHZ flag. Exceptions handlers must be
421 wrapped as well. Irqs are already protected inside
422 rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on
423 irq exit still need to be protected.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200424
Frederic Weisbeckerb9527412012-06-16 15:39:34 +0200425config HAVE_VIRT_CPU_ACCOUNTING
426 bool
427
Kevin Hilman554b0002013-09-16 15:28:21 -0700428config HAVE_VIRT_CPU_ACCOUNTING_GEN
429 bool
430 default y if 64BIT
431 help
432 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
433 Before enabling this option, arch code must be audited
434 to ensure there are no races in concurrent read/write of
435 cputime_t. For example, reading/writing 64-bit cputime_t on
436 some 32-bit arches may require multiple accesses, so proper
437 locking is needed to protect against concurrent accesses.
438
439
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200440config HAVE_IRQ_TIME_ACCOUNTING
441 bool
442 help
443 Archs need to ensure they use a high enough resolution clock to
444 support irq time accounting and then call enable_sched_clock_irqtime().
445
Gerald Schaefer15626062012-10-08 16:30:04 -0700446config HAVE_ARCH_TRANSPARENT_HUGEPAGE
447 bool
448
Toshi Kani0ddab1d2015-04-14 15:47:20 -0700449config HAVE_ARCH_HUGE_VMAP
450 bool
451
Pavel Emelyanov0f8975e2013-07-03 15:01:20 -0700452config HAVE_ARCH_SOFT_DIRTY
453 bool
454
David Howells786d35d2012-09-28 14:31:03 +0930455config HAVE_MOD_ARCH_SPECIFIC
456 bool
457 help
458 The arch uses struct mod_arch_specific to store data. Many arches
459 just need a simple module loader without arch specific data - those
460 should not enable this.
461
462config MODULES_USE_ELF_RELA
463 bool
464 help
465 Modules only use ELF RELA relocations. Modules with ELF REL
466 relocations will give an error.
467
468config MODULES_USE_ELF_REL
469 bool
470 help
471 Modules only use ELF REL relocations. Modules with ELF RELA
472 relocations will give an error.
473
Rusty Russellb92021b2013-03-15 15:04:17 +1030474config HAVE_UNDERSCORE_SYMBOL_PREFIX
475 bool
476 help
477 Some architectures generate an _ in front of C symbols; things like
478 module loading and assembly files need to know about this.
479
Frederic Weisbeckercc1f0272013-09-24 17:17:47 +0200480config HAVE_IRQ_EXIT_ON_IRQ_STACK
481 bool
482 help
483 Architecture doesn't only execute the irq handler on the irq stack
484 but also irq_exit(). This way we can process softirqs on this irq
485 stack instead of switching to a new one when we call __do_softirq()
486 in the end of an hardirq.
487 This spares a stack switch and improves cache usage on softirq
488 processing.
489
Kirill A. Shutemov235a8f02015-04-14 15:46:17 -0700490config PGTABLE_LEVELS
491 int
492 default 2
493
Kees Cook2b68f6c2015-04-14 15:48:00 -0700494config ARCH_HAS_ELF_RANDOMIZE
495 bool
496 help
497 An architecture supports choosing randomized locations for
498 stack, mmap, brk, and ET_DYN. Defined functions:
499 - arch_mmap_rnd()
Kees Cook204db6e2015-04-14 15:48:12 -0700500 - arch_randomize_brk()
Kees Cook2b68f6c2015-04-14 15:48:00 -0700501
Al Virod2125042012-10-23 13:17:59 -0400502#
503# ABI hall of shame
504#
505config CLONE_BACKWARDS
506 bool
507 help
508 Architecture has tls passed as the 4th argument of clone(2),
509 not the 5th one.
510
511config CLONE_BACKWARDS2
512 bool
513 help
514 Architecture has the first two arguments of clone(2) swapped.
515
Michal Simekdfa97712013-08-13 16:00:53 -0700516config CLONE_BACKWARDS3
517 bool
518 help
519 Architecture has tls passed as the 3rd argument of clone(2),
520 not the 5th one.
521
Al Viroeaca6ea2012-11-25 23:12:10 -0500522config ODD_RT_SIGACTION
523 bool
524 help
525 Architecture has unusual rt_sigaction(2) arguments
526
Al Viro0a0e8cd2012-12-25 16:04:12 -0500527config OLD_SIGSUSPEND
528 bool
529 help
530 Architecture has old sigsuspend(2) syscall, of one-argument variety
531
532config OLD_SIGSUSPEND3
533 bool
534 help
535 Even weirder antique ABI - three-argument sigsuspend(2)
536
Al Viro495dfbf2012-12-25 19:09:45 -0500537config OLD_SIGACTION
538 bool
539 help
540 Architecture has old sigaction(2) syscall. Nope, not the same
541 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
542 but fairly different variant of sigaction(2), thanks to OSF/1
543 compatibility...
544
545config COMPAT_OLD_SIGACTION
546 bool
547
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -0700548source "kernel/gcov/Kconfig"