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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
Arthur Kepner74bc7ce2008-04-29 01:00:30 -0700208config HAVE_DMA_ATTRS
Jan Beulich9ba16082008-10-15 22:01:38 -0700209 bool
Jens Axboe3d442232008-06-26 11:21:34 +0200210
Marek Szyprowskic64be2b2011-12-29 13:09:51 +0100211config HAVE_DMA_CONTIGUOUS
212 bool
213
Thomas Gleixner29d5e042012-04-20 13:05:45 +0000214config GENERIC_SMP_IDLE_THREAD
215 bool
216
Kevin Hilman485cf5d2013-04-24 17:19:13 -0700217config GENERIC_IDLE_POLL_SETUP
218 bool
219
Thomas Gleixnera6359d12012-05-03 09:03:02 +0000220# Select if arch init_task initializer is different to init/init_task.c
221config ARCH_INIT_TASK
Thomas Gleixnera4a2eb42012-05-03 09:02:48 +0000222 bool
223
Thomas Gleixnerf5e10282012-05-05 15:05:48 +0000224# Select if arch has its private alloc_task_struct() function
225config ARCH_TASK_STRUCT_ALLOCATOR
226 bool
227
228# Select if arch has its private alloc_thread_info() function
229config ARCH_THREAD_INFO_ALLOCATOR
230 bool
231
Ingo Molnar5aaeb5c2015-07-17 12:28:12 +0200232# Select if arch wants to size task_struct dynamically via arch_task_struct_size:
233config ARCH_WANTS_DYNAMIC_TASK_STRUCT
234 bool
235
Heiko Carstensf850c30c2010-02-10 17:25:17 +0100236config HAVE_REGS_AND_STACK_ACCESS_API
237 bool
Heiko Carstense01292b2010-02-18 14:25:21 +0100238 help
239 This symbol should be selected by an architecure if it supports
240 the API needed to access registers and stack entries from pt_regs,
241 declared in asm/ptrace.h
242 For example the kprobes-based event tracer needs this API.
Heiko Carstensf850c30c2010-02-10 17:25:17 +0100243
David Brownell9483a572008-07-23 21:26:48 -0700244config HAVE_CLK
Jan Beulich9ba16082008-10-15 22:01:38 -0700245 bool
David Brownell9483a572008-07-23 21:26:48 -0700246 help
247 The <linux/clk.h> calls support software clock gating and
248 thus are a key power management tool on many systems.
249
Joerg Roedel5ee00bd2009-01-09 12:14:24 +0100250config HAVE_DMA_API_DEBUG
251 bool
Heiko Carstens36cd3c92009-04-09 18:48:34 +0200252
K.Prasad62a038d2009-06-01 23:43:33 +0530253config HAVE_HW_BREAKPOINT
254 bool
Frederic Weisbecker99e8c5a2009-12-17 01:33:54 +0100255 depends on PERF_EVENTS
K.Prasad62a038d2009-06-01 23:43:33 +0530256
Frederic Weisbecker01027522010-04-11 18:55:56 +0200257config HAVE_MIXED_BREAKPOINTS_REGS
258 bool
259 depends on HAVE_HW_BREAKPOINT
260 help
261 Depending on the arch implementation of hardware breakpoints,
262 some of them have separate registers for data and instruction
263 breakpoints addresses, others have mixed registers to store
264 them but define the access type in a control register.
265 Select this option if your arch implements breakpoints under the
266 latter fashion.
267
Avi Kivity7c68af62009-09-19 09:40:22 +0300268config HAVE_USER_RETURN_NOTIFIER
269 bool
Ingo Molnara1922ed2009-09-07 08:19:51 +0200270
Frederic Weisbeckerc01d4322010-05-15 22:57:48 +0200271config HAVE_PERF_EVENTS_NMI
272 bool
Frederic Weisbecker23637d42010-05-15 23:15:20 +0200273 help
274 System hardware can generate an NMI using the perf event
275 subsystem. Also has support for calculating CPU cycle events
276 to determine how many clock cycles in a given period.
Frederic Weisbeckerc01d4322010-05-15 22:57:48 +0200277
Jiri Olsac5e63192012-08-07 15:20:36 +0200278config HAVE_PERF_REGS
279 bool
280 help
281 Support selective register dumps for perf events. This includes
282 bit-mapping of each registers and a unique architecture id.
283
Jiri Olsac5ebced2012-08-07 15:20:40 +0200284config HAVE_PERF_USER_STACK_DUMP
285 bool
286 help
287 Support user stack dumps for perf event samples. This needs
288 access to the user stack pointer which is not unified across
289 architectures.
290
Jason Baronbf5438fc2010-09-17 11:09:00 -0400291config HAVE_ARCH_JUMP_LABEL
292 bool
293
Peter Zijlstra26723912011-05-24 17:12:00 -0700294config HAVE_RCU_TABLE_FREE
295 bool
296
Huang Yingdf013ff2011-07-13 13:14:22 +0800297config ARCH_HAVE_NMI_SAFE_CMPXCHG
298 bool
299
Heiko Carstens43570fd2012-01-12 17:17:27 -0800300config HAVE_ALIGNED_STRUCT_PAGE
301 bool
302 help
303 This makes sure that struct pages are double word aligned and that
304 e.g. the SLUB allocator can perform double word atomic operations
305 on a struct page for better performance. However selecting this
306 might increase the size of a struct page by a word.
307
Heiko Carstens41561532012-01-12 17:17:30 -0800308config HAVE_CMPXCHG_LOCAL
309 bool
310
Heiko Carstens25654092012-01-12 17:17:33 -0800311config HAVE_CMPXCHG_DOUBLE
312 bool
313
Will Deaconc1d7e012012-07-30 14:42:46 -0700314config ARCH_WANT_IPC_PARSE_VERSION
315 bool
316
317config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
318 bool
319
Chris Metcalf48b25c42012-03-15 13:13:38 -0400320config ARCH_WANT_OLD_COMPAT_IPC
Will Deaconc1d7e012012-07-30 14:42:46 -0700321 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
Chris Metcalf48b25c42012-03-15 13:13:38 -0400322 bool
323
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500324config HAVE_ARCH_SECCOMP_FILTER
325 bool
326 help
Will Drewryfb0fadf2012-04-12 16:48:02 -0500327 An arch should select this symbol if it provides all of these things:
Will Drewrybb6ea432012-04-12 16:48:01 -0500328 - syscall_get_arch()
329 - syscall_get_arguments()
330 - syscall_rollback()
331 - syscall_set_return_value()
Will Drewryfb0fadf2012-04-12 16:48:02 -0500332 - SIGSYS siginfo_t support
333 - secure_computing is called from a ptrace_event()-safe context
334 - secure_computing return value is checked and a return value of -1
335 results in the system call being skipped immediately.
Kees Cook48dc92b2014-06-25 16:08:24 -0700336 - seccomp syscall wired up
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500337
Andy Lutomirskiff27f382014-07-21 18:49:17 -0700338 For best performance, an arch should use seccomp_phase1 and
339 seccomp_phase2 directly. It should call seccomp_phase1 for all
340 syscalls if TIF_SECCOMP is set, but seccomp_phase1 does not
341 need to be called from a ptrace-safe context. It must then
342 call seccomp_phase2 if seccomp_phase1 returns anything other
343 than SECCOMP_PHASE1_OK or SECCOMP_PHASE1_SKIP.
344
345 As an additional optimization, an arch may provide seccomp_data
346 directly to seccomp_phase1; this avoids multiple calls
347 to the syscall_xyz helpers for every syscall.
348
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500349config SECCOMP_FILTER
350 def_bool y
351 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
352 help
353 Enable tasks to build secure computing environments defined
354 in terms of Berkeley Packet Filter programs which implement
355 task-defined system call filtering polices.
356
357 See Documentation/prctl/seccomp_filter.txt for details.
358
Kees Cook19952a92013-12-19 11:35:58 -0800359config HAVE_CC_STACKPROTECTOR
360 bool
361 help
362 An arch should select this symbol if:
363 - its compiler supports the -fstack-protector option
364 - it has implemented a stack canary (e.g. __stack_chk_guard)
365
366config CC_STACKPROTECTOR
Kees Cook87796572013-12-19 11:35:59 -0800367 def_bool n
Kees Cook19952a92013-12-19 11:35:58 -0800368 help
Kees Cook87796572013-12-19 11:35:59 -0800369 Set when a stack-protector mode is enabled, so that the build
370 can enable kernel-side support for the GCC feature.
371
372choice
373 prompt "Stack Protector buffer overflow detection"
374 depends on HAVE_CC_STACKPROTECTOR
375 default CC_STACKPROTECTOR_NONE
376 help
377 This option turns on the "stack-protector" GCC feature. This
Kees Cook19952a92013-12-19 11:35:58 -0800378 feature puts, at the beginning of functions, a canary value on
379 the stack just before the return address, and validates
380 the value just before actually returning. Stack based buffer
381 overflows (that need to overwrite this return address) now also
382 overwrite the canary, which gets detected and the attack is then
383 neutralized via a kernel panic.
384
Kees Cook87796572013-12-19 11:35:59 -0800385config CC_STACKPROTECTOR_NONE
386 bool "None"
387 help
388 Disable "stack-protector" GCC feature.
389
390config CC_STACKPROTECTOR_REGULAR
391 bool "Regular"
392 select CC_STACKPROTECTOR
393 help
394 Functions will have the stack-protector canary logic added if they
395 have an 8-byte or larger character array on the stack.
396
Kees Cook19952a92013-12-19 11:35:58 -0800397 This feature requires gcc version 4.2 or above, or a distribution
Kees Cook87796572013-12-19 11:35:59 -0800398 gcc with the feature backported ("-fstack-protector").
399
400 On an x86 "defconfig" build, this feature adds canary checks to
401 about 3% of all kernel functions, which increases kernel code size
402 by about 0.3%.
403
404config CC_STACKPROTECTOR_STRONG
405 bool "Strong"
406 select CC_STACKPROTECTOR
407 help
408 Functions will have the stack-protector canary logic added in any
409 of the following conditions:
410
411 - local variable's address used as part of the right hand side of an
412 assignment or function argument
413 - local variable is an array (or union containing an array),
414 regardless of array type or length
415 - uses register local variables
416
417 This feature requires gcc version 4.9 or above, or a distribution
418 gcc with the feature backported ("-fstack-protector-strong").
419
420 On an x86 "defconfig" build, this feature adds canary checks to
421 about 20% of all kernel functions, which increases the kernel code
422 size by about 2%.
423
424endchoice
Kees Cook19952a92013-12-19 11:35:58 -0800425
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100426config HAVE_CONTEXT_TRACKING
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200427 bool
428 help
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100429 Provide kernel/user boundaries probes necessary for subsystems
430 that need it, such as userspace RCU extended quiescent state.
431 Syscalls need to be wrapped inside user_exit()-user_enter() through
432 the slow path using TIF_NOHZ flag. Exceptions handlers must be
433 wrapped as well. Irqs are already protected inside
434 rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on
435 irq exit still need to be protected.
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200436
Frederic Weisbeckerb9527412012-06-16 15:39:34 +0200437config HAVE_VIRT_CPU_ACCOUNTING
438 bool
439
Kevin Hilman554b0002013-09-16 15:28:21 -0700440config HAVE_VIRT_CPU_ACCOUNTING_GEN
441 bool
442 default y if 64BIT
443 help
444 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
445 Before enabling this option, arch code must be audited
446 to ensure there are no races in concurrent read/write of
447 cputime_t. For example, reading/writing 64-bit cputime_t on
448 some 32-bit arches may require multiple accesses, so proper
449 locking is needed to protect against concurrent accesses.
450
451
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200452config HAVE_IRQ_TIME_ACCOUNTING
453 bool
454 help
455 Archs need to ensure they use a high enough resolution clock to
456 support irq time accounting and then call enable_sched_clock_irqtime().
457
Gerald Schaefer15626062012-10-08 16:30:04 -0700458config HAVE_ARCH_TRANSPARENT_HUGEPAGE
459 bool
460
Toshi Kani0ddab1d2015-04-14 15:47:20 -0700461config HAVE_ARCH_HUGE_VMAP
462 bool
463
Pavel Emelyanov0f8975e2013-07-03 15:01:20 -0700464config HAVE_ARCH_SOFT_DIRTY
465 bool
466
David Howells786d35d2012-09-28 14:31:03 +0930467config HAVE_MOD_ARCH_SPECIFIC
468 bool
469 help
470 The arch uses struct mod_arch_specific to store data. Many arches
471 just need a simple module loader without arch specific data - those
472 should not enable this.
473
474config MODULES_USE_ELF_RELA
475 bool
476 help
477 Modules only use ELF RELA relocations. Modules with ELF REL
478 relocations will give an error.
479
480config MODULES_USE_ELF_REL
481 bool
482 help
483 Modules only use ELF REL relocations. Modules with ELF RELA
484 relocations will give an error.
485
Rusty Russellb92021b2013-03-15 15:04:17 +1030486config HAVE_UNDERSCORE_SYMBOL_PREFIX
487 bool
488 help
489 Some architectures generate an _ in front of C symbols; things like
490 module loading and assembly files need to know about this.
491
Frederic Weisbeckercc1f0272013-09-24 17:17:47 +0200492config HAVE_IRQ_EXIT_ON_IRQ_STACK
493 bool
494 help
495 Architecture doesn't only execute the irq handler on the irq stack
496 but also irq_exit(). This way we can process softirqs on this irq
497 stack instead of switching to a new one when we call __do_softirq()
498 in the end of an hardirq.
499 This spares a stack switch and improves cache usage on softirq
500 processing.
501
Kirill A. Shutemov235a8f02015-04-14 15:46:17 -0700502config PGTABLE_LEVELS
503 int
504 default 2
505
Kees Cook2b68f6c2015-04-14 15:48:00 -0700506config ARCH_HAS_ELF_RANDOMIZE
507 bool
508 help
509 An architecture supports choosing randomized locations for
510 stack, mmap, brk, and ET_DYN. Defined functions:
511 - arch_mmap_rnd()
Kees Cook204db6e2015-04-14 15:48:12 -0700512 - arch_randomize_brk()
Kees Cook2b68f6c2015-04-14 15:48:00 -0700513
Daniel Cashmand07e2252016-01-14 15:19:53 -0800514config HAVE_ARCH_MMAP_RND_BITS
515 bool
516 help
517 An arch should select this symbol if it supports setting a variable
518 number of bits for use in establishing the base address for mmap
519 allocations, has MMU enabled and provides values for both:
520 - ARCH_MMAP_RND_BITS_MIN
521 - ARCH_MMAP_RND_BITS_MAX
522
523config ARCH_MMAP_RND_BITS_MIN
524 int
525
526config ARCH_MMAP_RND_BITS_MAX
527 int
528
529config ARCH_MMAP_RND_BITS_DEFAULT
530 int
531
532config ARCH_MMAP_RND_BITS
533 int "Number of bits to use for ASLR of mmap base address" if EXPERT
534 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
535 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
536 default ARCH_MMAP_RND_BITS_MIN
537 depends on HAVE_ARCH_MMAP_RND_BITS
538 help
539 This value can be used to select the number of bits to use to
540 determine the random offset to the base address of vma regions
541 resulting from mmap allocations. This value will be bounded
542 by the architecture's minimum and maximum supported values.
543
544 This value can be changed after boot using the
545 /proc/sys/vm/mmap_rnd_bits tunable
546
547config HAVE_ARCH_MMAP_RND_COMPAT_BITS
548 bool
549 help
550 An arch should select this symbol if it supports running applications
551 in compatibility mode, supports setting a variable number of bits for
552 use in establishing the base address for mmap allocations, has MMU
553 enabled and provides values for both:
554 - ARCH_MMAP_RND_COMPAT_BITS_MIN
555 - ARCH_MMAP_RND_COMPAT_BITS_MAX
556
557config ARCH_MMAP_RND_COMPAT_BITS_MIN
558 int
559
560config ARCH_MMAP_RND_COMPAT_BITS_MAX
561 int
562
563config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
564 int
565
566config ARCH_MMAP_RND_COMPAT_BITS
567 int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
568 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
569 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
570 default ARCH_MMAP_RND_COMPAT_BITS_MIN
571 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
572 help
573 This value can be used to select the number of bits to use to
574 determine the random offset to the base address of vma regions
575 resulting from mmap allocations for compatible applications This
576 value will be bounded by the architecture's minimum and maximum
577 supported values.
578
579 This value can be changed after boot using the
580 /proc/sys/vm/mmap_rnd_compat_bits tunable
581
Josh Triplett3033f14a2015-06-25 15:01:19 -0700582config HAVE_COPY_THREAD_TLS
583 bool
584 help
585 Architecture provides copy_thread_tls to accept tls argument via
586 normal C parameter passing, rather than extracting the syscall
587 argument from pt_regs.
588
Al Virod2125042012-10-23 13:17:59 -0400589#
590# ABI hall of shame
591#
592config CLONE_BACKWARDS
593 bool
594 help
595 Architecture has tls passed as the 4th argument of clone(2),
596 not the 5th one.
597
598config CLONE_BACKWARDS2
599 bool
600 help
601 Architecture has the first two arguments of clone(2) swapped.
602
Michal Simekdfa97712013-08-13 16:00:53 -0700603config CLONE_BACKWARDS3
604 bool
605 help
606 Architecture has tls passed as the 3rd argument of clone(2),
607 not the 5th one.
608
Al Viroeaca6ea2012-11-25 23:12:10 -0500609config ODD_RT_SIGACTION
610 bool
611 help
612 Architecture has unusual rt_sigaction(2) arguments
613
Al Viro0a0e8cd2012-12-25 16:04:12 -0500614config OLD_SIGSUSPEND
615 bool
616 help
617 Architecture has old sigsuspend(2) syscall, of one-argument variety
618
619config OLD_SIGSUSPEND3
620 bool
621 help
622 Even weirder antique ABI - three-argument sigsuspend(2)
623
Al Viro495dfbf2012-12-25 19:09:45 -0500624config OLD_SIGACTION
625 bool
626 help
627 Architecture has old sigaction(2) syscall. Nope, not the same
628 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
629 but fairly different variant of sigaction(2), thanks to OSF/1
630 compatibility...
631
632config COMPAT_OLD_SIGACTION
633 bool
634
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -0700635source "kernel/gcov/Kconfig"