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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
Petr Mladek42a0bb32016-05-20 17:00:33 -0700190config HAVE_NMI
191 bool
192
Cong Wangd314d742012-03-23 15:01:51 -0700193config HAVE_NMI_WATCHDOG
Petr Mladek42a0bb32016-05-20 17:00:33 -0700194 depends on HAVE_NMI
Cong Wangd314d742012-03-23 15:01:51 -0700195 bool
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700196#
197# An arch should select this if it provides all these things:
198#
199# task_pt_regs() in asm/processor.h or asm/ptrace.h
200# arch_has_single_step() if there is hardware single-step support
201# arch_has_block_step() if there is hardware block-step support
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700202# asm/syscall.h supplying asm-generic/syscall.h interface
203# linux/regset.h user_regset interfaces
204# CORE_DUMP_USE_REGSET #define'd in linux/elf.h
205# TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit}
206# TIF_NOTIFY_RESUME calls tracehook_notify_resume()
207# signal delivery calls tracehook_signal_handler()
208#
209config HAVE_ARCH_TRACEHOOK
Jan Beulich9ba16082008-10-15 22:01:38 -0700210 bool
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700211
Marek Szyprowskic64be2b2011-12-29 13:09:51 +0100212config HAVE_DMA_CONTIGUOUS
213 bool
214
Thomas Gleixner29d5e042012-04-20 13:05:45 +0000215config GENERIC_SMP_IDLE_THREAD
216 bool
217
Kevin Hilman485cf5d2013-04-24 17:19:13 -0700218config GENERIC_IDLE_POLL_SETUP
219 bool
220
Thomas Gleixnera6359d12012-05-03 09:03:02 +0000221# Select if arch init_task initializer is different to init/init_task.c
222config ARCH_INIT_TASK
Thomas Gleixnera4a2eb42012-05-03 09:02:48 +0000223 bool
224
Thomas Gleixnerf5e10282012-05-05 15:05:48 +0000225# Select if arch has its private alloc_task_struct() function
226config ARCH_TASK_STRUCT_ALLOCATOR
227 bool
228
Linus Torvaldsb235bee2016-06-24 15:09:37 -0700229# Select if arch has its private alloc_thread_stack() function
230config ARCH_THREAD_STACK_ALLOCATOR
Thomas Gleixnerf5e10282012-05-05 15:05:48 +0000231 bool
232
Ingo Molnar5aaeb5c2015-07-17 12:28:12 +0200233# Select if arch wants to size task_struct dynamically via arch_task_struct_size:
234config ARCH_WANTS_DYNAMIC_TASK_STRUCT
235 bool
236
Heiko Carstensf850c30c2010-02-10 17:25:17 +0100237config HAVE_REGS_AND_STACK_ACCESS_API
238 bool
Heiko Carstense01292b2010-02-18 14:25:21 +0100239 help
240 This symbol should be selected by an architecure if it supports
241 the API needed to access registers and stack entries from pt_regs,
242 declared in asm/ptrace.h
243 For example the kprobes-based event tracer needs this API.
Heiko Carstensf850c30c2010-02-10 17:25:17 +0100244
David Brownell9483a572008-07-23 21:26:48 -0700245config HAVE_CLK
Jan Beulich9ba16082008-10-15 22:01:38 -0700246 bool
David Brownell9483a572008-07-23 21:26:48 -0700247 help
248 The <linux/clk.h> calls support software clock gating and
249 thus are a key power management tool on many systems.
250
Joerg Roedel5ee00bd2009-01-09 12:14:24 +0100251config HAVE_DMA_API_DEBUG
252 bool
Heiko Carstens36cd3c92009-04-09 18:48:34 +0200253
K.Prasad62a038d2009-06-01 23:43:33 +0530254config HAVE_HW_BREAKPOINT
255 bool
Frederic Weisbecker99e8c5a2009-12-17 01:33:54 +0100256 depends on PERF_EVENTS
K.Prasad62a038d2009-06-01 23:43:33 +0530257
Frederic Weisbecker01027522010-04-11 18:55:56 +0200258config HAVE_MIXED_BREAKPOINTS_REGS
259 bool
260 depends on HAVE_HW_BREAKPOINT
261 help
262 Depending on the arch implementation of hardware breakpoints,
263 some of them have separate registers for data and instruction
264 breakpoints addresses, others have mixed registers to store
265 them but define the access type in a control register.
266 Select this option if your arch implements breakpoints under the
267 latter fashion.
268
Avi Kivity7c68af62009-09-19 09:40:22 +0300269config HAVE_USER_RETURN_NOTIFIER
270 bool
Ingo Molnara1922ed2009-09-07 08:19:51 +0200271
Frederic Weisbeckerc01d4322010-05-15 22:57:48 +0200272config HAVE_PERF_EVENTS_NMI
273 bool
Frederic Weisbecker23637d42010-05-15 23:15:20 +0200274 help
275 System hardware can generate an NMI using the perf event
276 subsystem. Also has support for calculating CPU cycle events
277 to determine how many clock cycles in a given period.
Frederic Weisbeckerc01d4322010-05-15 22:57:48 +0200278
Jiri Olsac5e63192012-08-07 15:20:36 +0200279config HAVE_PERF_REGS
280 bool
281 help
282 Support selective register dumps for perf events. This includes
283 bit-mapping of each registers and a unique architecture id.
284
Jiri Olsac5ebced2012-08-07 15:20:40 +0200285config HAVE_PERF_USER_STACK_DUMP
286 bool
287 help
288 Support user stack dumps for perf event samples. This needs
289 access to the user stack pointer which is not unified across
290 architectures.
291
Jason Baronbf5438fc2010-09-17 11:09:00 -0400292config HAVE_ARCH_JUMP_LABEL
293 bool
294
Peter Zijlstra26723912011-05-24 17:12:00 -0700295config HAVE_RCU_TABLE_FREE
296 bool
297
Huang Yingdf013ff2011-07-13 13:14:22 +0800298config ARCH_HAVE_NMI_SAFE_CMPXCHG
299 bool
300
Heiko Carstens43570fd2012-01-12 17:17:27 -0800301config HAVE_ALIGNED_STRUCT_PAGE
302 bool
303 help
304 This makes sure that struct pages are double word aligned and that
305 e.g. the SLUB allocator can perform double word atomic operations
306 on a struct page for better performance. However selecting this
307 might increase the size of a struct page by a word.
308
Heiko Carstens41561532012-01-12 17:17:30 -0800309config HAVE_CMPXCHG_LOCAL
310 bool
311
Heiko Carstens25654092012-01-12 17:17:33 -0800312config HAVE_CMPXCHG_DOUBLE
313 bool
314
Will Deaconc1d7e012012-07-30 14:42:46 -0700315config ARCH_WANT_IPC_PARSE_VERSION
316 bool
317
318config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
319 bool
320
Chris Metcalf48b25c42012-03-15 13:13:38 -0400321config ARCH_WANT_OLD_COMPAT_IPC
Will Deaconc1d7e012012-07-30 14:42:46 -0700322 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
Chris Metcalf48b25c42012-03-15 13:13:38 -0400323 bool
324
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500325config HAVE_ARCH_SECCOMP_FILTER
326 bool
327 help
Will Drewryfb0fadf2012-04-12 16:48:02 -0500328 An arch should select this symbol if it provides all of these things:
Will Drewrybb6ea432012-04-12 16:48:01 -0500329 - syscall_get_arch()
330 - syscall_get_arguments()
331 - syscall_rollback()
332 - syscall_set_return_value()
Will Drewryfb0fadf2012-04-12 16:48:02 -0500333 - SIGSYS siginfo_t support
334 - secure_computing is called from a ptrace_event()-safe context
335 - secure_computing return value is checked and a return value of -1
336 results in the system call being skipped immediately.
Kees Cook48dc92b2014-06-25 16:08:24 -0700337 - seccomp syscall wired up
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500338
Andy Lutomirskiff27f382014-07-21 18:49:17 -0700339 For best performance, an arch should use seccomp_phase1 and
340 seccomp_phase2 directly. It should call seccomp_phase1 for all
341 syscalls if TIF_SECCOMP is set, but seccomp_phase1 does not
342 need to be called from a ptrace-safe context. It must then
343 call seccomp_phase2 if seccomp_phase1 returns anything other
344 than SECCOMP_PHASE1_OK or SECCOMP_PHASE1_SKIP.
345
346 As an additional optimization, an arch may provide seccomp_data
347 directly to seccomp_phase1; this avoids multiple calls
348 to the syscall_xyz helpers for every syscall.
349
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500350config SECCOMP_FILTER
351 def_bool y
352 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
353 help
354 Enable tasks to build secure computing environments defined
355 in terms of Berkeley Packet Filter programs which implement
356 task-defined system call filtering polices.
357
358 See Documentation/prctl/seccomp_filter.txt for details.
359
Kees Cook19952a92013-12-19 11:35:58 -0800360config HAVE_CC_STACKPROTECTOR
361 bool
362 help
363 An arch should select this symbol if:
364 - its compiler supports the -fstack-protector option
365 - it has implemented a stack canary (e.g. __stack_chk_guard)
366
367config CC_STACKPROTECTOR
Kees Cook87796572013-12-19 11:35:59 -0800368 def_bool n
Kees Cook19952a92013-12-19 11:35:58 -0800369 help
Kees Cook87796572013-12-19 11:35:59 -0800370 Set when a stack-protector mode is enabled, so that the build
371 can enable kernel-side support for the GCC feature.
372
373choice
374 prompt "Stack Protector buffer overflow detection"
375 depends on HAVE_CC_STACKPROTECTOR
376 default CC_STACKPROTECTOR_NONE
377 help
378 This option turns on the "stack-protector" GCC feature. This
Kees Cook19952a92013-12-19 11:35:58 -0800379 feature puts, at the beginning of functions, a canary value on
380 the stack just before the return address, and validates
381 the value just before actually returning. Stack based buffer
382 overflows (that need to overwrite this return address) now also
383 overwrite the canary, which gets detected and the attack is then
384 neutralized via a kernel panic.
385
Kees Cook87796572013-12-19 11:35:59 -0800386config CC_STACKPROTECTOR_NONE
387 bool "None"
388 help
389 Disable "stack-protector" GCC feature.
390
391config CC_STACKPROTECTOR_REGULAR
392 bool "Regular"
393 select CC_STACKPROTECTOR
394 help
395 Functions will have the stack-protector canary logic added if they
396 have an 8-byte or larger character array on the stack.
397
Kees Cook19952a92013-12-19 11:35:58 -0800398 This feature requires gcc version 4.2 or above, or a distribution
Kees Cook87796572013-12-19 11:35:59 -0800399 gcc with the feature backported ("-fstack-protector").
400
401 On an x86 "defconfig" build, this feature adds canary checks to
402 about 3% of all kernel functions, which increases kernel code size
403 by about 0.3%.
404
405config CC_STACKPROTECTOR_STRONG
406 bool "Strong"
407 select CC_STACKPROTECTOR
408 help
409 Functions will have the stack-protector canary logic added in any
410 of the following conditions:
411
412 - local variable's address used as part of the right hand side of an
413 assignment or function argument
414 - local variable is an array (or union containing an array),
415 regardless of array type or length
416 - uses register local variables
417
418 This feature requires gcc version 4.9 or above, or a distribution
419 gcc with the feature backported ("-fstack-protector-strong").
420
421 On an x86 "defconfig" build, this feature adds canary checks to
422 about 20% of all kernel functions, which increases the kernel code
423 size by about 2%.
424
425endchoice
Kees Cook19952a92013-12-19 11:35:58 -0800426
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100427config HAVE_CONTEXT_TRACKING
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200428 bool
429 help
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100430 Provide kernel/user boundaries probes necessary for subsystems
431 that need it, such as userspace RCU extended quiescent state.
432 Syscalls need to be wrapped inside user_exit()-user_enter() through
433 the slow path using TIF_NOHZ flag. Exceptions handlers must be
434 wrapped as well. Irqs are already protected inside
435 rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on
436 irq exit still need to be protected.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200437
Frederic Weisbeckerb9527412012-06-16 15:39:34 +0200438config HAVE_VIRT_CPU_ACCOUNTING
439 bool
440
Kevin Hilman554b0002013-09-16 15:28:21 -0700441config HAVE_VIRT_CPU_ACCOUNTING_GEN
442 bool
443 default y if 64BIT
444 help
445 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
446 Before enabling this option, arch code must be audited
447 to ensure there are no races in concurrent read/write of
448 cputime_t. For example, reading/writing 64-bit cputime_t on
449 some 32-bit arches may require multiple accesses, so proper
450 locking is needed to protect against concurrent accesses.
451
452
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200453config HAVE_IRQ_TIME_ACCOUNTING
454 bool
455 help
456 Archs need to ensure they use a high enough resolution clock to
457 support irq time accounting and then call enable_sched_clock_irqtime().
458
Gerald Schaefer15626062012-10-08 16:30:04 -0700459config HAVE_ARCH_TRANSPARENT_HUGEPAGE
460 bool
461
Toshi Kani0ddab1d2015-04-14 15:47:20 -0700462config HAVE_ARCH_HUGE_VMAP
463 bool
464
Pavel Emelyanov0f8975e2013-07-03 15:01:20 -0700465config HAVE_ARCH_SOFT_DIRTY
466 bool
467
David Howells786d35d2012-09-28 14:31:03 +0930468config HAVE_MOD_ARCH_SPECIFIC
469 bool
470 help
471 The arch uses struct mod_arch_specific to store data. Many arches
472 just need a simple module loader without arch specific data - those
473 should not enable this.
474
475config MODULES_USE_ELF_RELA
476 bool
477 help
478 Modules only use ELF RELA relocations. Modules with ELF REL
479 relocations will give an error.
480
481config MODULES_USE_ELF_REL
482 bool
483 help
484 Modules only use ELF REL relocations. Modules with ELF RELA
485 relocations will give an error.
486
Rusty Russellb92021b2013-03-15 15:04:17 +1030487config HAVE_UNDERSCORE_SYMBOL_PREFIX
488 bool
489 help
490 Some architectures generate an _ in front of C symbols; things like
491 module loading and assembly files need to know about this.
492
Frederic Weisbeckercc1f0272013-09-24 17:17:47 +0200493config HAVE_IRQ_EXIT_ON_IRQ_STACK
494 bool
495 help
496 Architecture doesn't only execute the irq handler on the irq stack
497 but also irq_exit(). This way we can process softirqs on this irq
498 stack instead of switching to a new one when we call __do_softirq()
499 in the end of an hardirq.
500 This spares a stack switch and improves cache usage on softirq
501 processing.
502
Kirill A. Shutemov235a8f02015-04-14 15:46:17 -0700503config PGTABLE_LEVELS
504 int
505 default 2
506
Kees Cook2b68f6c2015-04-14 15:48:00 -0700507config ARCH_HAS_ELF_RANDOMIZE
508 bool
509 help
510 An architecture supports choosing randomized locations for
511 stack, mmap, brk, and ET_DYN. Defined functions:
512 - arch_mmap_rnd()
Kees Cook204db6e2015-04-14 15:48:12 -0700513 - arch_randomize_brk()
Kees Cook2b68f6c2015-04-14 15:48:00 -0700514
Daniel Cashmand07e2252016-01-14 15:19:53 -0800515config HAVE_ARCH_MMAP_RND_BITS
516 bool
517 help
518 An arch should select this symbol if it supports setting a variable
519 number of bits for use in establishing the base address for mmap
520 allocations, has MMU enabled and provides values for both:
521 - ARCH_MMAP_RND_BITS_MIN
522 - ARCH_MMAP_RND_BITS_MAX
523
Jiri Slaby5f56a5d2016-05-20 17:00:16 -0700524config HAVE_EXIT_THREAD
525 bool
526 help
527 An architecture implements exit_thread.
528
Daniel Cashmand07e2252016-01-14 15:19:53 -0800529config ARCH_MMAP_RND_BITS_MIN
530 int
531
532config ARCH_MMAP_RND_BITS_MAX
533 int
534
535config ARCH_MMAP_RND_BITS_DEFAULT
536 int
537
538config ARCH_MMAP_RND_BITS
539 int "Number of bits to use for ASLR of mmap base address" if EXPERT
540 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
541 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
542 default ARCH_MMAP_RND_BITS_MIN
543 depends on HAVE_ARCH_MMAP_RND_BITS
544 help
545 This value can be used to select the number of bits to use to
546 determine the random offset to the base address of vma regions
547 resulting from mmap allocations. This value will be bounded
548 by the architecture's minimum and maximum supported values.
549
550 This value can be changed after boot using the
551 /proc/sys/vm/mmap_rnd_bits tunable
552
553config HAVE_ARCH_MMAP_RND_COMPAT_BITS
554 bool
555 help
556 An arch should select this symbol if it supports running applications
557 in compatibility mode, supports setting a variable number of bits for
558 use in establishing the base address for mmap allocations, has MMU
559 enabled and provides values for both:
560 - ARCH_MMAP_RND_COMPAT_BITS_MIN
561 - ARCH_MMAP_RND_COMPAT_BITS_MAX
562
563config ARCH_MMAP_RND_COMPAT_BITS_MIN
564 int
565
566config ARCH_MMAP_RND_COMPAT_BITS_MAX
567 int
568
569config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
570 int
571
572config ARCH_MMAP_RND_COMPAT_BITS
573 int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
574 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
575 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
576 default ARCH_MMAP_RND_COMPAT_BITS_MIN
577 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
578 help
579 This value can be used to select the number of bits to use to
580 determine the random offset to the base address of vma regions
581 resulting from mmap allocations for compatible applications This
582 value will be bounded by the architecture's minimum and maximum
583 supported values.
584
585 This value can be changed after boot using the
586 /proc/sys/vm/mmap_rnd_compat_bits tunable
587
Josh Triplett3033f14a2015-06-25 15:01:19 -0700588config HAVE_COPY_THREAD_TLS
589 bool
590 help
591 Architecture provides copy_thread_tls to accept tls argument via
592 normal C parameter passing, rather than extracting the syscall
593 argument from pt_regs.
594
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600595config HAVE_STACK_VALIDATION
596 bool
597 help
598 Architecture supports the 'objtool check' host tool command, which
599 performs compile-time stack metadata validation.
600
George Spelvin468a9422016-05-26 22:11:51 -0400601config HAVE_ARCH_HASH
602 bool
603 default n
604 help
605 If this is set, the architecture provides an <asm/hash.h>
606 file which provides platform-specific implementations of some
607 functions in <linux/hash.h> or fs/namei.c.
608
William Breathitt Gray3a495512016-05-27 18:08:27 -0400609config ISA_BUS_API
610 def_bool ISA
611
Al Virod2125042012-10-23 13:17:59 -0400612#
613# ABI hall of shame
614#
615config CLONE_BACKWARDS
616 bool
617 help
618 Architecture has tls passed as the 4th argument of clone(2),
619 not the 5th one.
620
621config CLONE_BACKWARDS2
622 bool
623 help
624 Architecture has the first two arguments of clone(2) swapped.
625
Michal Simekdfa97712013-08-13 16:00:53 -0700626config CLONE_BACKWARDS3
627 bool
628 help
629 Architecture has tls passed as the 3rd argument of clone(2),
630 not the 5th one.
631
Al Viroeaca6ea2012-11-25 23:12:10 -0500632config ODD_RT_SIGACTION
633 bool
634 help
635 Architecture has unusual rt_sigaction(2) arguments
636
Al Viro0a0e8cd2012-12-25 16:04:12 -0500637config OLD_SIGSUSPEND
638 bool
639 help
640 Architecture has old sigsuspend(2) syscall, of one-argument variety
641
642config OLD_SIGSUSPEND3
643 bool
644 help
645 Even weirder antique ABI - three-argument sigsuspend(2)
646
Al Viro495dfbf2012-12-25 19:09:45 -0500647config OLD_SIGACTION
648 bool
649 help
650 Architecture has old sigaction(2) syscall. Nope, not the same
651 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
652 but fairly different variant of sigaction(2), thanks to OSF/1
653 compatibility...
654
655config COMPAT_OLD_SIGACTION
656 bool
657
Christoph Hellwig0d4a6192016-01-20 15:01:22 -0800658config ARCH_NO_COHERENT_DMA_MMAP
659 bool
660
Zhaoxiu Zengfff7fb02016-05-20 17:03:57 -0700661config CPU_NO_EFFICIENT_FFS
662 def_bool n
663
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -0700664source "kernel/gcov/Kconfig"