ublk: fail to recover device if queue setup is interrupted
[linux-block.git] / arch / Kconfig
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b2441318 1# SPDX-License-Identifier: GPL-2.0
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MD
2#
3# General architecture dependent options
4#
125e5645 5
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CH
6#
7# Note: arch/$(SRCARCH)/Kconfig needs to be included first so that it can
8# override the default values in this file.
9#
10source "arch/$(SRCARCH)/Kconfig"
11
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RD
12menu "General architecture-dependent options"
13
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HB
14config CRASH_CORE
15 bool
16
2965faa5 17config KEXEC_CORE
692f66f2 18 select CRASH_CORE
2965faa5
DY
19 bool
20
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SS
21config KEXEC_ELF
22 bool
23
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TJB
24config HAVE_IMA_KEXEC
25 bool
26
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CM
27config ARCH_HAS_SUBPAGE_FAULTS
28 bool
29 help
30 Select if the architecture can check permissions at sub-page
31 granularity (e.g. arm64 MTE). The probe_user_*() functions
32 must be implemented.
33
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TG
34config HOTPLUG_SMT
35 bool
36
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TG
37# Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLUG_CORE_SYNC_FULL
38config HOTPLUG_CORE_SYNC
39 bool
40
41# Basic CPU dead synchronization selected by architecture
42config HOTPLUG_CORE_SYNC_DEAD
43 bool
44 select HOTPLUG_CORE_SYNC
45
46# Full CPU synchronization with alive state selected by architecture
47config HOTPLUG_CORE_SYNC_FULL
48 bool
49 select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
50 select HOTPLUG_CORE_SYNC
51
a631be92
TG
52config HOTPLUG_SPLIT_STARTUP
53 bool
54 select HOTPLUG_CORE_SYNC_FULL
55
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TG
56config HOTPLUG_PARALLEL
57 bool
58 select HOTPLUG_SPLIT_STARTUP
59
142781e1 60config GENERIC_ENTRY
9f79ffc1 61 bool
142781e1 62
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MD
63config KPROBES
64 bool "Kprobes"
05ed160e 65 depends on MODULES
125e5645 66 depends on HAVE_KPROBES
05ed160e 67 select KALLSYMS
835f14ed 68 select TASKS_RCU if PREEMPTION
125e5645
MD
69 help
70 Kprobes allows you to trap at almost any kernel address and
71 execute a callback function. register_kprobe() establishes
72 a probepoint and specifies the callback. Kprobes is useful
73 for kernel debugging, non-intrusive instrumentation and testing.
74 If in doubt, say "N".
75
45f81b1c 76config JUMP_LABEL
24b54fee
KK
77 bool "Optimize very unlikely/likely branches"
78 depends on HAVE_ARCH_JUMP_LABEL
4ab7674f 79 select OBJTOOL if HAVE_JUMP_LABEL_HACK
24b54fee 80 help
9f79ffc1
JH
81 This option enables a transparent branch optimization that
82 makes certain almost-always-true or almost-always-false branch
83 conditions even cheaper to execute within the kernel.
c5905afb 84
9f79ffc1
JH
85 Certain performance-sensitive kernel code, such as trace points,
86 scheduler functionality, networking code and KVM have such
87 branches and include support for this optimization technique.
c5905afb 88
9f79ffc1
JH
89 If it is detected that the compiler has support for "asm goto",
90 the kernel will compile such branches with just a nop
91 instruction. When the condition flag is toggled to true, the
92 nop will be converted to a jump instruction to execute the
93 conditional block of instructions.
c5905afb 94
9f79ffc1
JH
95 This technique lowers overhead and stress on the branch prediction
96 of the processor and generally makes the kernel faster. The update
97 of the condition is slower, but those are always very rare.
45f81b1c 98
9f79ffc1
JH
99 ( On 32-bit x86, the necessary options added to the compiler
100 flags may increase the size of the kernel slightly. )
45f81b1c 101
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PZ
102config STATIC_KEYS_SELFTEST
103 bool "Static key selftest"
104 depends on JUMP_LABEL
105 help
106 Boot time self-test of the branch patching code.
107
f03c4129
PZ
108config STATIC_CALL_SELFTEST
109 bool "Static call selftest"
110 depends on HAVE_STATIC_CALL
111 help
112 Boot time self-test of the call patching code.
113
afd66255 114config OPTPROBES
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MH
115 def_bool y
116 depends on KPROBES && HAVE_OPTPROBES
01b1d88b 117 select TASKS_RCU if PREEMPTION
afd66255 118
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MH
119config KPROBES_ON_FTRACE
120 def_bool y
121 depends on KPROBES && HAVE_KPROBES_ON_FTRACE
122 depends on DYNAMIC_FTRACE_WITH_REGS
123 help
9f79ffc1
JH
124 If function tracer is enabled and the arch supports full
125 passing of pt_regs to function tracing, then kprobes can
126 optimize on top of function tracing.
e7dbfe34 127
2b144498 128config UPROBES
09294e31 129 def_bool n
e8f4aa60 130 depends on ARCH_SUPPORTS_UPROBES
2b144498 131 help
7b2d81d4
IM
132 Uprobes is the user-space counterpart to kprobes: they
133 enable instrumentation applications (such as 'perf probe')
134 to establish unintrusive probes in user-space binaries and
135 libraries, by executing handler functions when the probes
136 are hit by user-space applications.
137
138 ( These probes come in the form of single-byte breakpoints,
139 managed by the kernel and kept transparent to the probed
140 application. )
2b144498 141
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SRV
142config HAVE_64BIT_ALIGNED_ACCESS
143 def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
144 help
145 Some architectures require 64 bit accesses to be 64 bit
146 aligned, which also requires structs containing 64 bit values
147 to be 64 bit aligned too. This includes some 32 bit
148 architectures which can do 64 bit accesses, as well as 64 bit
149 architectures without unaligned access.
150
151 This symbol should be selected by an architecture if 64 bit
152 accesses are required to be 64 bit aligned in this way even
153 though it is not a 64 bit architecture.
154
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155 See Documentation/core-api/unaligned-memory-access.rst for
156 more information on the topic of unaligned memory accesses.
adab66b7 157
58340a07 158config HAVE_EFFICIENT_UNALIGNED_ACCESS
9ba16087 159 bool
58340a07
JB
160 help
161 Some architectures are unable to perform unaligned accesses
162 without the use of get_unaligned/put_unaligned. Others are
163 unable to perform such accesses efficiently (e.g. trap on
164 unaligned access and require fixing it up in the exception
165 handler.)
166
167 This symbol should be selected by an architecture if it can
168 perform unaligned accesses efficiently to allow different
169 code paths to be selected for these cases. Some network
170 drivers, for example, could opt to not fix up alignment
171 problems with received packets if doing so would not help
172 much.
173
c9b54d6f 174 See Documentation/core-api/unaligned-memory-access.rst for more
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JB
175 information on the topic of unaligned memory accesses.
176
cf66bb93 177config ARCH_USE_BUILTIN_BSWAP
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KK
178 bool
179 help
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JH
180 Modern versions of GCC (since 4.4) have builtin functions
181 for handling byte-swapping. Using these, instead of the old
182 inline assembler that the architecture code provides in the
183 __arch_bswapXX() macros, allows the compiler to see what's
184 happening and offers more opportunity for optimisation. In
185 particular, the compiler will be able to combine the byteswap
186 with a nearby load or store and use load-and-swap or
187 store-and-swap instructions if the architecture has them. It
188 should almost *never* result in code which is worse than the
189 hand-coded assembler in <asm/swab.h>. But just in case it
190 does, the use of the builtins is optional.
cf66bb93 191
9f79ffc1
JH
192 Any architecture with load-and-swap or store-and-swap
193 instructions should set this. And it shouldn't hurt to set it
194 on architectures that don't have such instructions.
cf66bb93 195
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AM
196config KRETPROBES
197 def_bool y
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198 depends on KPROBES && (HAVE_KRETPROBES || HAVE_RETHOOK)
199
200config KRETPROBE_ON_RETHOOK
201 def_bool y
202 depends on HAVE_RETHOOK
203 depends on KRETPROBES
204 select RETHOOK
9edddaa2 205
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AK
206config USER_RETURN_NOTIFIER
207 bool
208 depends on HAVE_USER_RETURN_NOTIFIER
209 help
210 Provide a kernel-internal notification when a cpu is about to
211 switch to user mode.
212
28b2ee20 213config HAVE_IOREMAP_PROT
9ba16087 214 bool
28b2ee20 215
125e5645 216config HAVE_KPROBES
9ba16087 217 bool
9edddaa2
AM
218
219config HAVE_KRETPROBES
9ba16087 220 bool
74bc7cee 221
afd66255
MH
222config HAVE_OPTPROBES
223 bool
d314d74c 224
e7dbfe34
MH
225config HAVE_KPROBES_ON_FTRACE
226 bool
227
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MH
228config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
229 bool
230 help
231 Since kretprobes modifies return address on the stack, the
232 stacktrace may see the kretprobe trampoline address instead
233 of correct one. If the architecture stacktrace code and
234 unwinder can adjust such entries, select this configuration.
235
540adea3 236config HAVE_FUNCTION_ERROR_INJECTION
9802d865
JB
237 bool
238
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PM
239config HAVE_NMI
240 bool
241
a257cacc
CL
242config HAVE_FUNCTION_DESCRIPTORS
243 bool
244
4aae683f
MY
245config TRACE_IRQFLAGS_SUPPORT
246 bool
247
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MR
248config TRACE_IRQFLAGS_NMI_SUPPORT
249 bool
250
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RM
251#
252# An arch should select this if it provides all these things:
253#
254# task_pt_regs() in asm/processor.h or asm/ptrace.h
255# arch_has_single_step() if there is hardware single-step support
256# arch_has_block_step() if there is hardware block-step support
1f5a4ad9
RM
257# asm/syscall.h supplying asm-generic/syscall.h interface
258# linux/regset.h user_regset interfaces
259# CORE_DUMP_USE_REGSET #define'd in linux/elf.h
153474ba 260# TIF_SYSCALL_TRACE calls ptrace_report_syscall_{entry,exit}
03248add 261# TIF_NOTIFY_RESUME calls resume_user_mode_work()
1f5a4ad9
RM
262#
263config HAVE_ARCH_TRACEHOOK
9ba16087 264 bool
1f5a4ad9 265
c64be2bb
MS
266config HAVE_DMA_CONTIGUOUS
267 bool
268
29d5e047 269config GENERIC_SMP_IDLE_THREAD
24b54fee 270 bool
29d5e047 271
485cf5da 272config GENERIC_IDLE_POLL_SETUP
24b54fee 273 bool
485cf5da 274
6974f0c4
DM
275config ARCH_HAS_FORTIFY_SOURCE
276 bool
277 help
278 An architecture should select this when it can successfully
279 build and run with CONFIG_FORTIFY_SOURCE.
280
d8ae8a37
CH
281#
282# Select if the arch provides a historic keepinit alias for the retain_initrd
283# command line option
284#
285config ARCH_HAS_KEEPINITRD
286 bool
287
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DB
288# Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
289config ARCH_HAS_SET_MEMORY
290 bool
291
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RE
292# Select if arch has all set_direct_map_invalid/default() functions
293config ARCH_HAS_SET_DIRECT_MAP
294 bool
295
c30700db 296#
fa7e2247 297# Select if the architecture provides the arch_dma_set_uncached symbol to
a86ecfa6 298# either provide an uncached segment alias for a DMA allocation, or
fa7e2247 299# to remap the page tables in place.
c30700db 300#
fa7e2247 301config ARCH_HAS_DMA_SET_UNCACHED
c30700db
CH
302 bool
303
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CH
304#
305# Select if the architectures provides the arch_dma_clear_uncached symbol
306# to undo an in-place page table remap for uncached access.
307#
308config ARCH_HAS_DMA_CLEAR_UNCACHED
c30700db
CH
309 bool
310
7725acaa
TG
311config ARCH_HAS_CPU_FINALIZE_INIT
312 bool
313
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DH
314# Select if arch init_task must go in the __init_task_data section
315config ARCH_TASK_STRUCT_ON_STACK
24b54fee 316 bool
a4a2eb49 317
f5e10287
TG
318# Select if arch has its private alloc_task_struct() function
319config ARCH_TASK_STRUCT_ALLOCATOR
320 bool
321
5905429a
KC
322config HAVE_ARCH_THREAD_STRUCT_WHITELIST
323 bool
324 depends on !ARCH_TASK_STRUCT_ALLOCATOR
325 help
326 An architecture should select this to provide hardened usercopy
327 knowledge about what region of the thread_struct should be
328 whitelisted for copying to userspace. Normally this is only the
329 FPU registers. Specifically, arch_thread_struct_whitelist()
330 should be implemented. Without this, the entire thread_struct
331 field in task_struct will be left whitelisted.
332
b235beea
LT
333# Select if arch has its private alloc_thread_stack() function
334config ARCH_THREAD_STACK_ALLOCATOR
f5e10287
TG
335 bool
336
5aaeb5c0
IM
337# Select if arch wants to size task_struct dynamically via arch_task_struct_size:
338config ARCH_WANTS_DYNAMIC_TASK_STRUCT
339 bool
340
51c2ee6d
ND
341config ARCH_WANTS_NO_INSTR
342 bool
343 help
344 An architecture should select this if the noinstr macro is being used on
345 functions to denote that the toolchain should avoid instrumenting such
346 functions and is required for correctness.
347
942fa985
YN
348config ARCH_32BIT_OFF_T
349 bool
350 depends on !64BIT
351 help
352 All new 32-bit architectures should have 64-bit off_t type on
353 userspace side which corresponds to the loff_t kernel type. This
354 is the requirement for modern ABIs. Some existing architectures
355 still support 32-bit off_t. This option is enabled for all such
356 architectures explicitly.
357
96c0a6a7
HC
358# Selected by 64 bit architectures which have a 32 bit f_tinode in struct ustat
359config ARCH_32BIT_USTAT_F_TINODE
360 bool
361
2ff2b7ec
MY
362config HAVE_ASM_MODVERSIONS
363 bool
364 help
a86ecfa6 365 This symbol should be selected by an architecture if it provides
2ff2b7ec
MY
366 <asm/asm-prototypes.h> to support the module versioning for symbols
367 exported from assembly code.
368
f850c30c
HC
369config HAVE_REGS_AND_STACK_ACCESS_API
370 bool
e01292b1 371 help
a86ecfa6 372 This symbol should be selected by an architecture if it supports
e01292b1
HC
373 the API needed to access registers and stack entries from pt_regs,
374 declared in asm/ptrace.h
375 For example the kprobes-based event tracer needs this API.
f850c30c 376
d7822b1e
MD
377config HAVE_RSEQ
378 bool
379 depends on HAVE_REGS_AND_STACK_ACCESS_API
380 help
381 This symbol should be selected by an architecture if it
382 supports an implementation of restartable sequences.
383
2f7ab126
MO
384config HAVE_RUST
385 bool
386 help
387 This symbol should be selected by an architecture if it
388 supports Rust.
389
3c88ee19
MH
390config HAVE_FUNCTION_ARG_ACCESS_API
391 bool
392 help
a86ecfa6 393 This symbol should be selected by an architecture if it supports
3c88ee19
MH
394 the API needed to access function arguments from pt_regs,
395 declared in asm/ptrace.h
396
62a038d3
P
397config HAVE_HW_BREAKPOINT
398 bool
99e8c5a3 399 depends on PERF_EVENTS
62a038d3 400
0102752e
FW
401config HAVE_MIXED_BREAKPOINTS_REGS
402 bool
403 depends on HAVE_HW_BREAKPOINT
404 help
405 Depending on the arch implementation of hardware breakpoints,
406 some of them have separate registers for data and instruction
407 breakpoints addresses, others have mixed registers to store
408 them but define the access type in a control register.
409 Select this option if your arch implements breakpoints under the
410 latter fashion.
411
7c68af6e
AK
412config HAVE_USER_RETURN_NOTIFIER
413 bool
a1922ed6 414
c01d4323
FW
415config HAVE_PERF_EVENTS_NMI
416 bool
23637d47
FW
417 help
418 System hardware can generate an NMI using the perf event
419 subsystem. Also has support for calculating CPU cycle events
420 to determine how many clock cycles in a given period.
c01d4323 421
05a4a952
NP
422config HAVE_HARDLOCKUP_DETECTOR_PERF
423 bool
424 depends on HAVE_PERF_EVENTS_NMI
425 help
426 The arch chooses to use the generic perf-NMI-based hardlockup
427 detector. Must define HAVE_PERF_EVENTS_NMI.
428
05a4a952
NP
429config HAVE_HARDLOCKUP_DETECTOR_ARCH
430 bool
05a4a952 431 help
1356d0b9
PM
432 The arch provides its own hardlockup detector implementation instead
433 of the generic ones.
434
435 It uses the same command line parameters, and sysctl interface,
436 as the generic hardlockup detectors.
05a4a952 437
c5e63197
JO
438config HAVE_PERF_REGS
439 bool
440 help
441 Support selective register dumps for perf events. This includes
442 bit-mapping of each registers and a unique architecture id.
443
c5ebcedb
JO
444config HAVE_PERF_USER_STACK_DUMP
445 bool
446 help
447 Support user stack dumps for perf event samples. This needs
448 access to the user stack pointer which is not unified across
449 architectures.
450
bf5438fc
JB
451config HAVE_ARCH_JUMP_LABEL
452 bool
453
50ff18ab
AB
454config HAVE_ARCH_JUMP_LABEL_RELATIVE
455 bool
456
0d6e24d4
PZ
457config MMU_GATHER_TABLE_FREE
458 bool
459
ff2e6d72 460config MMU_GATHER_RCU_TABLE_FREE
26723911 461 bool
0d6e24d4 462 select MMU_GATHER_TABLE_FREE
26723911 463
3af4bd03 464config MMU_GATHER_PAGE_SIZE
ed6a7935
PZ
465 bool
466
27796d03
PZ
467config MMU_GATHER_NO_RANGE
468 bool
1e9fdf21
PZ
469 select MMU_GATHER_MERGE_VMAS
470
471config MMU_GATHER_NO_FLUSH_CACHE
472 bool
473
474config MMU_GATHER_MERGE_VMAS
475 bool
27796d03 476
580a586c 477config MMU_GATHER_NO_GATHER
952a31c9 478 bool
0d6e24d4 479 depends on MMU_GATHER_TABLE_FREE
952a31c9 480
d53c3dfb
NP
481config ARCH_WANT_IRQS_OFF_ACTIVATE_MM
482 bool
483 help
484 Temporary select until all architectures can be converted to have
485 irqs disabled over activate_mm. Architectures that do IPI based TLB
486 shootdowns should enable this.
487
88e3009b
NP
488# Use normal mm refcounting for MMU_LAZY_TLB kernel thread references.
489# MMU_LAZY_TLB_REFCOUNT=n can improve the scalability of context switching
490# to/from kernel threads when the same mm is running on a lot of CPUs (a large
491# multi-threaded application), by reducing contention on the mm refcount.
492#
493# This can be disabled if the architecture ensures no CPUs are using an mm as a
494# "lazy tlb" beyond its final refcount (i.e., by the time __mmdrop frees the mm
495# or its kernel page tables). This could be arranged by arch_exit_mmap(), or
496# final exit(2) TLB flush, for example.
497#
498# To implement this, an arch *must*:
499# Ensure the _lazy_tlb variants of mmgrab/mmdrop are used when manipulating
500# the lazy tlb reference of a kthread's ->active_mm (non-arch code has been
501# converted already).
502config MMU_LAZY_TLB_REFCOUNT
503 def_bool y
2655421a
NP
504 depends on !MMU_LAZY_TLB_SHOOTDOWN
505
506# This option allows MMU_LAZY_TLB_REFCOUNT=n. It ensures no CPUs are using an
507# mm as a lazy tlb beyond its last reference count, by shooting down these
508# users before the mm is deallocated. __mmdrop() first IPIs all CPUs that may
509# be using the mm as a lazy tlb, so that they may switch themselves to using
510# init_mm for their active mm. mm_cpumask(mm) is used to determine which CPUs
511# may be using mm as a lazy tlb mm.
512#
513# To implement this, an arch *must*:
514# - At the time of the final mmdrop of the mm, ensure mm_cpumask(mm) contains
515# at least all possible CPUs in which the mm is lazy.
516# - It must meet the requirements for MMU_LAZY_TLB_REFCOUNT=n (see above).
517config MMU_LAZY_TLB_SHOOTDOWN
518 bool
88e3009b 519
df013ffb
HY
520config ARCH_HAVE_NMI_SAFE_CMPXCHG
521 bool
522
2e83b879
PM
523config ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
524 bool
525
43570fd2
HC
526config HAVE_ALIGNED_STRUCT_PAGE
527 bool
528 help
529 This makes sure that struct pages are double word aligned and that
530 e.g. the SLUB allocator can perform double word atomic operations
531 on a struct page for better performance. However selecting this
532 might increase the size of a struct page by a word.
533
4156153c
HC
534config HAVE_CMPXCHG_LOCAL
535 bool
536
2565409f
HC
537config HAVE_CMPXCHG_DOUBLE
538 bool
539
77e58496
PM
540config ARCH_WEAK_RELEASE_ACQUIRE
541 bool
542
c1d7e01d
WD
543config ARCH_WANT_IPC_PARSE_VERSION
544 bool
545
546config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
547 bool
548
48b25c43 549config ARCH_WANT_OLD_COMPAT_IPC
c1d7e01d 550 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
48b25c43
CM
551 bool
552
282a181b
YZ
553config HAVE_ARCH_SECCOMP
554 bool
555 help
556 An arch should select this symbol to support seccomp mode 1 (the fixed
557 syscall policy), and must provide an overrides for __NR_seccomp_sigreturn,
558 and compat syscalls if the asm-generic/seccomp.h defaults need adjustment:
559 - __NR_seccomp_read_32
560 - __NR_seccomp_write_32
561 - __NR_seccomp_exit_32
562 - __NR_seccomp_sigreturn_32
563
e2cfabdf
WD
564config HAVE_ARCH_SECCOMP_FILTER
565 bool
282a181b 566 select HAVE_ARCH_SECCOMP
e2cfabdf 567 help
fb0fadf9 568 An arch should select this symbol if it provides all of these things:
282a181b 569 - all the requirements for HAVE_ARCH_SECCOMP
bb6ea430
WD
570 - syscall_get_arch()
571 - syscall_get_arguments()
572 - syscall_rollback()
573 - syscall_set_return_value()
fb0fadf9
WD
574 - SIGSYS siginfo_t support
575 - secure_computing is called from a ptrace_event()-safe context
576 - secure_computing return value is checked and a return value of -1
577 results in the system call being skipped immediately.
48dc92b9 578 - seccomp syscall wired up
0d8315dd
YZ
579 - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE,
580 SECCOMP_ARCH_NATIVE_NR, SECCOMP_ARCH_NATIVE_NAME defined. If
581 COMPAT is supported, have the SECCOMP_ARCH_COMPAT* defines too.
e2cfabdf 582
282a181b
YZ
583config SECCOMP
584 prompt "Enable seccomp to safely execute untrusted bytecode"
585 def_bool y
586 depends on HAVE_ARCH_SECCOMP
587 help
588 This kernel feature is useful for number crunching applications
589 that may need to handle untrusted bytecode during their
590 execution. By using pipes or other transports made available
591 to the process as file descriptors supporting the read/write
592 syscalls, it's possible to isolate those applications in their
593 own address space using seccomp. Once seccomp is enabled via
594 prctl(PR_SET_SECCOMP) or the seccomp() syscall, it cannot be
595 disabled and the task is only allowed to execute a few safe
596 syscalls defined by each seccomp mode.
597
598 If unsure, say Y.
599
e2cfabdf
WD
600config SECCOMP_FILTER
601 def_bool y
602 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
603 help
604 Enable tasks to build secure computing environments defined
605 in terms of Berkeley Packet Filter programs which implement
606 task-defined system call filtering polices.
607
5fb94e9c 608 See Documentation/userspace-api/seccomp_filter.rst for details.
e2cfabdf 609
0d8315dd
YZ
610config SECCOMP_CACHE_DEBUG
611 bool "Show seccomp filter cache status in /proc/pid/seccomp_cache"
612 depends on SECCOMP_FILTER && !HAVE_SPARSE_SYSCALL_NR
613 depends on PROC_FS
614 help
615 This enables the /proc/pid/seccomp_cache interface to monitor
616 seccomp cache data. The file format is subject to change. Reading
617 the file requires CAP_SYS_ADMIN.
618
619 This option is for debugging only. Enabling presents the risk that
620 an adversary may be able to infer the seccomp filter logic.
621
622 If unsure, say N.
623
afaef01c
AP
624config HAVE_ARCH_STACKLEAK
625 bool
626 help
627 An architecture should select this if it has the code which
628 fills the used part of the kernel stack with the STACKLEAK_POISON
629 value before returning from system calls.
630
d148eac0 631config HAVE_STACKPROTECTOR
19952a92
KC
632 bool
633 help
634 An arch should select this symbol if:
19952a92
KC
635 - it has implemented a stack canary (e.g. __stack_chk_guard)
636
050e9baa 637config STACKPROTECTOR
2a61f474 638 bool "Stack Protector buffer overflow detection"
d148eac0 639 depends on HAVE_STACKPROTECTOR
2a61f474
MY
640 depends on $(cc-option,-fstack-protector)
641 default y
19952a92 642 help
8779657d 643 This option turns on the "stack-protector" GCC feature. This
19952a92
KC
644 feature puts, at the beginning of functions, a canary value on
645 the stack just before the return address, and validates
646 the value just before actually returning. Stack based buffer
647 overflows (that need to overwrite this return address) now also
648 overwrite the canary, which gets detected and the attack is then
649 neutralized via a kernel panic.
650
8779657d
KC
651 Functions will have the stack-protector canary logic added if they
652 have an 8-byte or larger character array on the stack.
653
19952a92 654 This feature requires gcc version 4.2 or above, or a distribution
8779657d
KC
655 gcc with the feature backported ("-fstack-protector").
656
657 On an x86 "defconfig" build, this feature adds canary checks to
658 about 3% of all kernel functions, which increases kernel code size
659 by about 0.3%.
660
050e9baa 661config STACKPROTECTOR_STRONG
2a61f474 662 bool "Strong Stack Protector"
050e9baa 663 depends on STACKPROTECTOR
2a61f474
MY
664 depends on $(cc-option,-fstack-protector-strong)
665 default y
8779657d
KC
666 help
667 Functions will have the stack-protector canary logic added in any
668 of the following conditions:
669
670 - local variable's address used as part of the right hand side of an
671 assignment or function argument
672 - local variable is an array (or union containing an array),
673 regardless of array type or length
674 - uses register local variables
675
676 This feature requires gcc version 4.9 or above, or a distribution
677 gcc with the feature backported ("-fstack-protector-strong").
678
679 On an x86 "defconfig" build, this feature adds canary checks to
680 about 20% of all kernel functions, which increases the kernel code
681 size by about 2%.
682
d08b9f0c
ST
683config ARCH_SUPPORTS_SHADOW_CALL_STACK
684 bool
685 help
afcf5441
DL
686 An architecture should select this if it supports the compiler's
687 Shadow Call Stack and implements runtime support for shadow stack
aa7a65ae 688 switching.
d08b9f0c
ST
689
690config SHADOW_CALL_STACK
afcf5441
DL
691 bool "Shadow Call Stack"
692 depends on ARCH_SUPPORTS_SHADOW_CALL_STACK
38792972 693 depends on DYNAMIC_FTRACE_WITH_ARGS || DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER
d08b9f0c 694 help
afcf5441
DL
695 This option enables the compiler's Shadow Call Stack, which
696 uses a shadow stack to protect function return addresses from
697 being overwritten by an attacker. More information can be found
698 in the compiler's documentation:
d08b9f0c 699
afcf5441
DL
700 - Clang: https://clang.llvm.org/docs/ShadowCallStack.html
701 - GCC: https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options
d08b9f0c
ST
702
703 Note that security guarantees in the kernel differ from the
704 ones documented for user space. The kernel must store addresses
705 of shadow stacks in memory, which means an attacker capable of
706 reading and writing arbitrary memory may be able to locate them
707 and hijack control flow by modifying the stacks.
708
9beccca0
AB
709config DYNAMIC_SCS
710 bool
711 help
712 Set by the arch code if it relies on code patching to insert the
713 shadow call stack push and pop instructions rather than on the
714 compiler.
715
dc5723b0
ST
716config LTO
717 bool
718 help
719 Selected if the kernel will be built using the compiler's LTO feature.
720
721config LTO_CLANG
722 bool
723 select LTO
724 help
725 Selected if the kernel will be built using Clang's LTO feature.
726
727config ARCH_SUPPORTS_LTO_CLANG
728 bool
729 help
730 An architecture should select this option if it supports:
731 - compiling with Clang,
732 - compiling inline assembly with Clang's integrated assembler,
733 - and linking with LLD.
734
735config ARCH_SUPPORTS_LTO_CLANG_THIN
736 bool
737 help
738 An architecture should select this option if it can support Clang's
739 ThinLTO mode.
740
741config HAS_LTO_CLANG
742 def_bool y
1e68a8af 743 depends on CC_IS_CLANG && LD_IS_LLD && AS_IS_LLVM
dc5723b0
ST
744 depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
745 depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
746 depends on ARCH_SUPPORTS_LTO_CLANG
747 depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT
bf3c2551 748 depends on !KASAN || KASAN_HW_TAGS
dc5723b0 749 depends on !GCOV_KERNEL
dc5723b0
ST
750 help
751 The compiler and Kconfig options support building with Clang's
752 LTO.
753
754choice
755 prompt "Link Time Optimization (LTO)"
756 default LTO_NONE
757 help
758 This option enables Link Time Optimization (LTO), which allows the
759 compiler to optimize binaries globally.
760
761 If unsure, select LTO_NONE. Note that LTO is very resource-intensive
762 so it's disabled by default.
763
764config LTO_NONE
765 bool "None"
766 help
767 Build the kernel normally, without Link Time Optimization (LTO).
768
769config LTO_CLANG_FULL
770 bool "Clang Full LTO (EXPERIMENTAL)"
771 depends on HAS_LTO_CLANG
772 depends on !COMPILE_TEST
773 select LTO_CLANG
774 help
9f79ffc1
JH
775 This option enables Clang's full Link Time Optimization (LTO), which
776 allows the compiler to optimize the kernel globally. If you enable
777 this option, the compiler generates LLVM bitcode instead of ELF
778 object files, and the actual compilation from bitcode happens at
779 the LTO link step, which may take several minutes depending on the
780 kernel configuration. More information can be found from LLVM's
781 documentation:
dc5723b0
ST
782
783 https://llvm.org/docs/LinkTimeOptimization.html
784
785 During link time, this option can use a large amount of RAM, and
786 may take much longer than the ThinLTO option.
787
788config LTO_CLANG_THIN
789 bool "Clang ThinLTO (EXPERIMENTAL)"
790 depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN
791 select LTO_CLANG
792 help
793 This option enables Clang's ThinLTO, which allows for parallel
794 optimization and faster incremental compiles compared to the
795 CONFIG_LTO_CLANG_FULL option. More information can be found
796 from Clang's documentation:
797
798 https://clang.llvm.org/docs/ThinLTO.html
799
800 If unsure, say Y.
801endchoice
802
cf68fffb
ST
803config ARCH_SUPPORTS_CFI_CLANG
804 bool
805 help
806 An architecture should select this option if it can support Clang's
807 Control-Flow Integrity (CFI) checking.
808
89245600
ST
809config ARCH_USES_CFI_TRAPS
810 bool
811
cf68fffb
ST
812config CFI_CLANG
813 bool "Use Clang's Control Flow Integrity (CFI)"
89245600
ST
814 depends on ARCH_SUPPORTS_CFI_CLANG
815 depends on $(cc-option,-fsanitize=kcfi)
cf68fffb
ST
816 help
817 This option enables Clang’s forward-edge Control Flow Integrity
818 (CFI) checking, where the compiler injects a runtime check to each
819 indirect function call to ensure the target is a valid function with
820 the correct static type. This restricts possible call targets and
821 makes it more difficult for an attacker to exploit bugs that allow
822 the modification of stored function pointers. More information can be
823 found from Clang's documentation:
824
825 https://clang.llvm.org/docs/ControlFlowIntegrity.html
826
cf68fffb
ST
827config CFI_PERMISSIVE
828 bool "Use CFI in permissive mode"
829 depends on CFI_CLANG
830 help
831 When selected, Control Flow Integrity (CFI) violations result in a
832 warning instead of a kernel panic. This option should only be used
833 for finding indirect call type mismatches during development.
834
835 If unsure, say N.
836
0f60a8ef
KC
837config HAVE_ARCH_WITHIN_STACK_FRAMES
838 bool
839 help
840 An architecture should select this if it can walk the kernel stack
841 frames to determine if an object is part of either the arguments
842 or local variables (i.e. that it excludes saved return addresses,
843 and similar) by implementing an inline arch_within_stack_frames(),
844 which is used by CONFIG_HARDENED_USERCOPY.
845
24a9c541 846config HAVE_CONTEXT_TRACKING_USER
2b1d5024
FW
847 bool
848 help
91d1aa43
FW
849 Provide kernel/user boundaries probes necessary for subsystems
850 that need it, such as userspace RCU extended quiescent state.
490f561b
FW
851 Syscalls need to be wrapped inside user_exit()-user_enter(), either
852 optimized behind static key or through the slow path using TIF_NOHZ
853 flag. Exceptions handlers must be wrapped as well. Irqs are already
6f0e6c15 854 protected inside ct_irq_enter/ct_irq_exit() but preemption or signal
490f561b
FW
855 handling on irq exit still need to be protected.
856
24a9c541 857config HAVE_CONTEXT_TRACKING_USER_OFFSTACK
83c2da2e
FW
858 bool
859 help
860 Architecture neither relies on exception_enter()/exception_exit()
861 nor on schedule_user(). Also preempt_schedule_notrace() and
862 preempt_schedule_irq() can't be called in a preemptible section
863 while context tracking is CONTEXT_USER. This feature reflects a sane
864 entry implementation where the following requirements are met on
865 critical entry code, ie: before user_exit() or after user_enter():
866
867 - Critical entry code isn't preemptible (or better yet:
868 not interruptible).
493c1822 869 - No use of RCU read side critical sections, unless ct_nmi_enter()
83c2da2e
FW
870 got called.
871 - No use of instrumentation, unless instrumentation_begin() got
872 called.
873
490f561b
FW
874config HAVE_TIF_NOHZ
875 bool
876 help
877 Arch relies on TIF_NOHZ and syscall slow path to implement context
878 tracking calls to user_enter()/user_exit().
2b1d5024 879
b952741c
FW
880config HAVE_VIRT_CPU_ACCOUNTING
881 bool
882
2b91ec9f
FW
883config HAVE_VIRT_CPU_ACCOUNTING_IDLE
884 bool
885 help
886 Architecture has its own way to account idle CPU time and therefore
887 doesn't implement vtime_account_idle().
888
40565b5a
SG
889config ARCH_HAS_SCALED_CPUTIME
890 bool
891
554b0004
KH
892config HAVE_VIRT_CPU_ACCOUNTING_GEN
893 bool
894 default y if 64BIT
895 help
896 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
897 Before enabling this option, arch code must be audited
898 to ensure there are no races in concurrent read/write of
899 cputime_t. For example, reading/writing 64-bit cputime_t on
900 some 32-bit arches may require multiple accesses, so proper
901 locking is needed to protect against concurrent accesses.
902
fdf9c356
FW
903config HAVE_IRQ_TIME_ACCOUNTING
904 bool
905 help
906 Archs need to ensure they use a high enough resolution clock to
907 support irq time accounting and then call enable_sched_clock_irqtime().
908
c49dd340
KS
909config HAVE_MOVE_PUD
910 bool
911 help
912 Architectures that select this are able to move page tables at the
913 PUD level. If there are only 3 page table levels, the move effectively
914 happens at the PGD level.
915
2c91bd4a
JFG
916config HAVE_MOVE_PMD
917 bool
918 help
919 Archs that select this are able to move page tables at the PMD level.
920
15626062
GS
921config HAVE_ARCH_TRANSPARENT_HUGEPAGE
922 bool
923
a00cc7d9
MW
924config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
925 bool
926
0ddab1d2
TK
927config HAVE_ARCH_HUGE_VMAP
928 bool
929
121e6f32
NP
930#
931# Archs that select this would be capable of PMD-sized vmaps (i.e.,
559089e0
SL
932# arch_vmap_pmd_supported() returns true). The VM_ALLOW_HUGE_VMAP flag
933# must be used to enable allocations to use hugepages.
121e6f32
NP
934#
935config HAVE_ARCH_HUGE_VMALLOC
936 depends on HAVE_ARCH_HUGE_VMAP
937 bool
938
3876d4a3
AG
939config ARCH_WANT_HUGE_PMD_SHARE
940 bool
941
0f8975ec
PE
942config HAVE_ARCH_SOFT_DIRTY
943 bool
944
786d35d4
DH
945config HAVE_MOD_ARCH_SPECIFIC
946 bool
947 help
948 The arch uses struct mod_arch_specific to store data. Many arches
949 just need a simple module loader without arch specific data - those
950 should not enable this.
951
952config MODULES_USE_ELF_RELA
953 bool
954 help
955 Modules only use ELF RELA relocations. Modules with ELF REL
956 relocations will give an error.
957
958config MODULES_USE_ELF_REL
959 bool
960 help
961 Modules only use ELF REL relocations. Modules with ELF RELA
962 relocations will give an error.
963
01dc0386
CL
964config ARCH_WANTS_MODULES_DATA_IN_VMALLOC
965 bool
966 help
967 For architectures like powerpc/32 which have constraints on module
968 allocation and need to allocate module data outside of module area.
969
cc1f0274
FW
970config HAVE_IRQ_EXIT_ON_IRQ_STACK
971 bool
972 help
973 Architecture doesn't only execute the irq handler on the irq stack
974 but also irq_exit(). This way we can process softirqs on this irq
975 stack instead of switching to a new one when we call __do_softirq()
976 in the end of an hardirq.
977 This spares a stack switch and improves cache usage on softirq
978 processing.
979
cd1a41ce
TG
980config HAVE_SOFTIRQ_ON_OWN_STACK
981 bool
982 help
983 Architecture provides a function to run __do_softirq() on a
c226bc3c 984 separate stack.
cd1a41ce 985
8cbb2b50
SAS
986config SOFTIRQ_ON_OWN_STACK
987 def_bool HAVE_SOFTIRQ_ON_OWN_STACK && !PREEMPT_RT
988
12700c17
AB
989config ALTERNATE_USER_ADDRESS_SPACE
990 bool
991 help
992 Architectures set this when the CPU uses separate address
993 spaces for kernel and user space pointers. In this case, the
994 access_ok() check on a __user pointer is skipped.
995
235a8f02
KS
996config PGTABLE_LEVELS
997 int
998 default 2
999
2b68f6ca
KC
1000config ARCH_HAS_ELF_RANDOMIZE
1001 bool
1002 help
1003 An architecture supports choosing randomized locations for
1004 stack, mmap, brk, and ET_DYN. Defined functions:
1005 - arch_mmap_rnd()
204db6ed 1006 - arch_randomize_brk()
2b68f6ca 1007
d07e2259
DC
1008config HAVE_ARCH_MMAP_RND_BITS
1009 bool
1010 help
1011 An arch should select this symbol if it supports setting a variable
1012 number of bits for use in establishing the base address for mmap
1013 allocations, has MMU enabled and provides values for both:
1014 - ARCH_MMAP_RND_BITS_MIN
1015 - ARCH_MMAP_RND_BITS_MAX
1016
5f56a5df
JS
1017config HAVE_EXIT_THREAD
1018 bool
1019 help
1020 An architecture implements exit_thread.
1021
d07e2259
DC
1022config ARCH_MMAP_RND_BITS_MIN
1023 int
1024
1025config ARCH_MMAP_RND_BITS_MAX
1026 int
1027
1028config ARCH_MMAP_RND_BITS_DEFAULT
1029 int
1030
1031config ARCH_MMAP_RND_BITS
1032 int "Number of bits to use for ASLR of mmap base address" if EXPERT
1033 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
1034 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
1035 default ARCH_MMAP_RND_BITS_MIN
1036 depends on HAVE_ARCH_MMAP_RND_BITS
1037 help
1038 This value can be used to select the number of bits to use to
1039 determine the random offset to the base address of vma regions
1040 resulting from mmap allocations. This value will be bounded
1041 by the architecture's minimum and maximum supported values.
1042
1043 This value can be changed after boot using the
1044 /proc/sys/vm/mmap_rnd_bits tunable
1045
1046config HAVE_ARCH_MMAP_RND_COMPAT_BITS
1047 bool
1048 help
1049 An arch should select this symbol if it supports running applications
1050 in compatibility mode, supports setting a variable number of bits for
1051 use in establishing the base address for mmap allocations, has MMU
1052 enabled and provides values for both:
1053 - ARCH_MMAP_RND_COMPAT_BITS_MIN
1054 - ARCH_MMAP_RND_COMPAT_BITS_MAX
1055
1056config ARCH_MMAP_RND_COMPAT_BITS_MIN
1057 int
1058
1059config ARCH_MMAP_RND_COMPAT_BITS_MAX
1060 int
1061
1062config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1063 int
1064
1065config ARCH_MMAP_RND_COMPAT_BITS
1066 int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
1067 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
1068 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1069 default ARCH_MMAP_RND_COMPAT_BITS_MIN
1070 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
1071 help
1072 This value can be used to select the number of bits to use to
1073 determine the random offset to the base address of vma regions
1074 resulting from mmap allocations for compatible applications This
1075 value will be bounded by the architecture's minimum and maximum
1076 supported values.
1077
1078 This value can be changed after boot using the
1079 /proc/sys/vm/mmap_rnd_compat_bits tunable
1080
1b028f78
DS
1081config HAVE_ARCH_COMPAT_MMAP_BASES
1082 bool
1083 help
1084 This allows 64bit applications to invoke 32-bit mmap() syscall
1085 and vice-versa 32-bit applications to call 64-bit mmap().
1086 Required for applications doing different bitness syscalls.
1087
1f0e290c
GR
1088config PAGE_SIZE_LESS_THAN_64KB
1089 def_bool y
1090 depends on !ARM64_64K_PAGES
1091 depends on !IA64_PAGE_SIZE_64KB
1092 depends on !PAGE_SIZE_64KB
1093 depends on !PARISC_PAGE_SIZE_64KB
e4bbd20d
NC
1094 depends on PAGE_SIZE_LESS_THAN_256KB
1095
1096config PAGE_SIZE_LESS_THAN_256KB
1097 def_bool y
1f0e290c
GR
1098 depends on !PAGE_SIZE_256KB
1099
67f3977f
AG
1100# This allows to use a set of generic functions to determine mmap base
1101# address by giving priority to top-down scheme only if the process
1102# is not in legacy mode (compat task, unlimited stack size or
1103# sysctl_legacy_va_layout).
1104# Architecture that selects this option can provide its own version of:
1105# - STACK_RND_MASK
1106config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
1107 bool
1108 depends on MMU
e7142bf5 1109 select ARCH_HAS_ELF_RANDOMIZE
67f3977f 1110
03f16cd0
JP
1111config HAVE_OBJTOOL
1112 bool
1113
4ab7674f
JP
1114config HAVE_JUMP_LABEL_HACK
1115 bool
1116
22102f45
JP
1117config HAVE_NOINSTR_HACK
1118 bool
1119
489e355b
JP
1120config HAVE_NOINSTR_VALIDATION
1121 bool
1122
5f3da8c0
JP
1123config HAVE_UACCESS_VALIDATION
1124 bool
1125 select OBJTOOL
1126
b9ab5ebb
JP
1127config HAVE_STACK_VALIDATION
1128 bool
1129 help
03f16cd0
JP
1130 Architecture supports objtool compile-time frame pointer rule
1131 validation.
b9ab5ebb 1132
af085d90
JP
1133config HAVE_RELIABLE_STACKTRACE
1134 bool
1135 help
140d7e88
MB
1136 Architecture has either save_stack_trace_tsk_reliable() or
1137 arch_stack_walk_reliable() function which only returns a stack trace
1138 if it can guarantee the trace is reliable.
af085d90 1139
468a9428
GS
1140config HAVE_ARCH_HASH
1141 bool
1142 default n
1143 help
1144 If this is set, the architecture provides an <asm/hash.h>
1145 file which provides platform-specific implementations of some
1146 functions in <linux/hash.h> or fs/namei.c.
1147
666047fe
FT
1148config HAVE_ARCH_NVRAM_OPS
1149 bool
1150
3a495511
WBG
1151config ISA_BUS_API
1152 def_bool ISA
1153
d2125043
AV
1154#
1155# ABI hall of shame
1156#
1157config CLONE_BACKWARDS
1158 bool
1159 help
1160 Architecture has tls passed as the 4th argument of clone(2),
1161 not the 5th one.
1162
1163config CLONE_BACKWARDS2
1164 bool
1165 help
1166 Architecture has the first two arguments of clone(2) swapped.
1167
dfa9771a
MS
1168config CLONE_BACKWARDS3
1169 bool
1170 help
1171 Architecture has tls passed as the 3rd argument of clone(2),
1172 not the 5th one.
1173
eaca6eae
AV
1174config ODD_RT_SIGACTION
1175 bool
1176 help
1177 Architecture has unusual rt_sigaction(2) arguments
1178
0a0e8cdf
AV
1179config OLD_SIGSUSPEND
1180 bool
1181 help
1182 Architecture has old sigsuspend(2) syscall, of one-argument variety
1183
1184config OLD_SIGSUSPEND3
1185 bool
1186 help
1187 Even weirder antique ABI - three-argument sigsuspend(2)
1188
495dfbf7
AV
1189config OLD_SIGACTION
1190 bool
1191 help
1192 Architecture has old sigaction(2) syscall. Nope, not the same
1193 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
1194 but fairly different variant of sigaction(2), thanks to OSF/1
1195 compatibility...
1196
1197config COMPAT_OLD_SIGACTION
1198 bool
1199
17435e5f 1200config COMPAT_32BIT_TIME
942437c9
AB
1201 bool "Provide system calls for 32-bit time_t"
1202 default !64BIT || COMPAT
17435e5f
DD
1203 help
1204 This enables 32 bit time_t support in addition to 64 bit time_t support.
1205 This is relevant on all 32-bit architectures, and 64-bit architectures
1206 as part of compat syscall handling.
1207
87a4c375
CH
1208config ARCH_NO_PREEMPT
1209 bool
1210
a50a3f4b
TG
1211config ARCH_SUPPORTS_RT
1212 bool
1213
fff7fb0b
ZZ
1214config CPU_NO_EFFICIENT_FFS
1215 def_bool n
1216
ba14a194
AL
1217config HAVE_ARCH_VMAP_STACK
1218 def_bool n
1219 help
1220 An arch should select this symbol if it can support kernel stacks
1221 in vmalloc space. This means:
1222
1223 - vmalloc space must be large enough to hold many kernel stacks.
1224 This may rule out many 32-bit architectures.
1225
1226 - Stacks in vmalloc space need to work reliably. For example, if
1227 vmap page tables are created on demand, either this mechanism
1228 needs to work while the stack points to a virtual address with
1229 unpopulated page tables or arch code (switch_to() and switch_mm(),
1230 most likely) needs to ensure that the stack's page table entries
1231 are populated before running on a possibly unpopulated stack.
1232
1233 - If the stack overflows into a guard page, something reasonable
1234 should happen. The definition of "reasonable" is flexible, but
1235 instantly rebooting without logging anything would be unfriendly.
1236
1237config VMAP_STACK
1238 default y
1239 bool "Use a virtually-mapped stack"
eafb149e 1240 depends on HAVE_ARCH_VMAP_STACK
38dd767d 1241 depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC
a7f7f624 1242 help
ba14a194
AL
1243 Enable this if you want the use virtually-mapped kernel stacks
1244 with guard pages. This causes kernel stack overflows to be
1245 caught immediately rather than causing difficult-to-diagnose
1246 corruption.
1247
38dd767d
AK
1248 To use this with software KASAN modes, the architecture must support
1249 backing virtual mappings with real shadow memory, and KASAN_VMALLOC
1250 must be enabled.
ba14a194 1251
39218ff4
KC
1252config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
1253 def_bool n
1254 help
1255 An arch should select this symbol if it can support kernel stack
1256 offset randomization with calls to add_random_kstack_offset()
1257 during syscall entry and choose_random_kstack_offset() during
1258 syscall exit. Careful removal of -fstack-protector-strong and
1259 -fstack-protector should also be applied to the entry code and
1260 closely examined, as the artificial stack bump looks like an array
1261 to the compiler, so it will attempt to add canary checks regardless
1262 of the static branch state.
1263
8cb37a59
ME
1264config RANDOMIZE_KSTACK_OFFSET
1265 bool "Support for randomizing kernel stack offset on syscall entry" if EXPERT
1266 default y
39218ff4 1267 depends on HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
efa90c11 1268 depends on INIT_STACK_NONE || !CC_IS_CLANG || CLANG_VERSION >= 140000
39218ff4
KC
1269 help
1270 The kernel stack offset can be randomized (after pt_regs) by
1271 roughly 5 bits of entropy, frustrating memory corruption
1272 attacks that depend on stack address determinism or
8cb37a59
ME
1273 cross-syscall address exposures.
1274
1275 The feature is controlled via the "randomize_kstack_offset=on/off"
1276 kernel boot param, and if turned off has zero overhead due to its use
1277 of static branches (see JUMP_LABEL).
1278
1279 If unsure, say Y.
1280
1281config RANDOMIZE_KSTACK_OFFSET_DEFAULT
1282 bool "Default state of kernel stack offset randomization"
1283 depends on RANDOMIZE_KSTACK_OFFSET
1284 help
1285 Kernel stack offset randomization is controlled by kernel boot param
1286 "randomize_kstack_offset=on/off", and this config chooses the default
1287 boot state.
39218ff4 1288
ad21fc4f
LA
1289config ARCH_OPTIONAL_KERNEL_RWX
1290 def_bool n
1291
1292config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1293 def_bool n
1294
1295config ARCH_HAS_STRICT_KERNEL_RWX
1296 def_bool n
1297
0f5bf6d0 1298config STRICT_KERNEL_RWX
ad21fc4f
LA
1299 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
1300 depends on ARCH_HAS_STRICT_KERNEL_RWX
1301 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1302 help
1303 If this is set, kernel text and rodata memory will be made read-only,
1304 and non-text memory will be made non-executable. This provides
1305 protection against certain security exploits (e.g. executing the heap
1306 or modifying text)
1307
1308 These features are considered standard security practice these days.
1309 You should say Y here in almost all cases.
1310
1311config ARCH_HAS_STRICT_MODULE_RWX
1312 def_bool n
1313
0f5bf6d0 1314config STRICT_MODULE_RWX
ad21fc4f
LA
1315 bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX
1316 depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES
1317 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1318 help
1319 If this is set, module text and rodata memory will be made read-only,
1320 and non-text memory will be made non-executable. This provides
1321 protection against certain security exploits (e.g. writing to text)
1322
ea8c64ac
CH
1323# select if the architecture provides an asm/dma-direct.h header
1324config ARCH_HAS_PHYS_TO_DMA
1325 bool
1326
04f264d3
PB
1327config HAVE_ARCH_COMPILER_H
1328 bool
1329 help
1330 An architecture can select this if it provides an
1331 asm/compiler.h header that should be included after
1332 linux/compiler-*.h in order to override macro definitions that those
1333 headers generally provide.
1334
271ca788
AB
1335config HAVE_ARCH_PREL32_RELOCATIONS
1336 bool
1337 help
1338 May be selected by an architecture if it supports place-relative
1339 32-bit relocations, both in the toolchain and in the module loader,
1340 in which case relative references can be used in special sections
1341 for PCI fixup, initcalls etc which are only half the size on 64 bit
1342 architectures, and don't require runtime relocation on relocatable
1343 kernels.
1344
ce9084ba
AB
1345config ARCH_USE_MEMREMAP_PROT
1346 bool
1347
fb346fd9
WL
1348config LOCK_EVENT_COUNTS
1349 bool "Locking event counts collection"
1350 depends on DEBUG_FS
a7f7f624 1351 help
fb346fd9
WL
1352 Enable light-weight counting of various locking related events
1353 in the system with minimal performance impact. This reduces
1354 the chance of application behavior change because of timing
1355 differences. The counts are reported via debugfs.
1356
5cf896fb
PC
1357# Select if the architecture has support for applying RELR relocations.
1358config ARCH_HAS_RELR
1359 bool
1360
1361config RELR
1362 bool "Use RELR relocation packing"
1363 depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR
1364 default y
1365 help
1366 Store the kernel's dynamic relocations in the RELR relocation packing
1367 format. Requires a compatible linker (LLD supports this feature), as
1368 well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy
1369 are compatible).
1370
0c9c1d56
TJB
1371config ARCH_HAS_MEM_ENCRYPT
1372 bool
1373
46b49b12
TL
1374config ARCH_HAS_CC_PLATFORM
1375 bool
1376
0e242208 1377config HAVE_SPARSE_SYSCALL_NR
9f79ffc1
JH
1378 bool
1379 help
1380 An architecture should select this if its syscall numbering is sparse
0e242208
HN
1381 to save space. For example, MIPS architecture has a syscall array with
1382 entries at 4000, 5000 and 6000 locations. This option turns on syscall
1383 related optimizations for a given architecture.
1384
d60d7de3
SS
1385config ARCH_HAS_VDSO_DATA
1386 bool
1387
115284d8
JP
1388config HAVE_STATIC_CALL
1389 bool
1390
9183c3f9
JP
1391config HAVE_STATIC_CALL_INLINE
1392 bool
1393 depends on HAVE_STATIC_CALL
03f16cd0 1394 select OBJTOOL
9183c3f9 1395
6ef869e0
MH
1396config HAVE_PREEMPT_DYNAMIC
1397 bool
99cf983c
MR
1398
1399config HAVE_PREEMPT_DYNAMIC_CALL
1400 bool
6ef869e0 1401 depends on HAVE_STATIC_CALL
99cf983c
MR
1402 select HAVE_PREEMPT_DYNAMIC
1403 help
9f79ffc1
JH
1404 An architecture should select this if it can handle the preemption
1405 model being selected at boot time using static calls.
99cf983c 1406
9f79ffc1
JH
1407 Where an architecture selects HAVE_STATIC_CALL_INLINE, any call to a
1408 preemption function will be patched directly.
99cf983c 1409
9f79ffc1
JH
1410 Where an architecture does not select HAVE_STATIC_CALL_INLINE, any
1411 call to a preemption function will go through a trampoline, and the
1412 trampoline will be patched.
99cf983c 1413
9f79ffc1
JH
1414 It is strongly advised to support inline static call to avoid any
1415 overhead.
99cf983c
MR
1416
1417config HAVE_PREEMPT_DYNAMIC_KEY
1418 bool
a0a12c3e 1419 depends on HAVE_ARCH_JUMP_LABEL
99cf983c 1420 select HAVE_PREEMPT_DYNAMIC
6ef869e0 1421 help
9f79ffc1
JH
1422 An architecture should select this if it can handle the preemption
1423 model being selected at boot time using static keys.
99cf983c 1424
9f79ffc1
JH
1425 Each preemption function will be given an early return based on a
1426 static key. This should have slightly lower overhead than non-inline
1427 static calls, as this effectively inlines each trampoline into the
1428 start of its callee. This may avoid redundant work, and may
1429 integrate better with CFI schemes.
99cf983c 1430
9f79ffc1
JH
1431 This will have greater overhead than using inline static calls as
1432 the call to the preemption function cannot be entirely elided.
6ef869e0 1433
59612b24
NC
1434config ARCH_WANT_LD_ORPHAN_WARN
1435 bool
1436 help
1437 An arch should select this symbol once all linker sections are explicitly
1438 included, size-asserted, or discarded in the linker scripts. This is
1439 important because we never want expected sections to be placed heuristically
1440 by the linker, since the locations of such sections can change between linker
1441 versions.
1442
4f5b0c17
MR
1443config HAVE_ARCH_PFN_VALID
1444 bool
1445
5d6ad668
MR
1446config ARCH_SUPPORTS_DEBUG_PAGEALLOC
1447 bool
1448
df4e817b
PT
1449config ARCH_SUPPORTS_PAGE_TABLE_CHECK
1450 bool
1451
2ca408d9
BG
1452config ARCH_SPLIT_ARG64
1453 bool
1454 help
9f79ffc1
JH
1455 If a 32-bit architecture requires 64-bit arguments to be split into
1456 pairs of 32-bit arguments, select this option.
2ca408d9 1457
7facdc42
AV
1458config ARCH_HAS_ELFCORE_COMPAT
1459 bool
1460
58e106e7
BS
1461config ARCH_HAS_PARANOID_L1D_FLUSH
1462 bool
1463
d593d64f
PS
1464config ARCH_HAVE_TRACE_MMIO_ACCESS
1465 bool
1466
1bdda24c
TG
1467config DYNAMIC_SIGFRAME
1468 bool
1469
50468e43
JS
1470# Select, if arch has a named attribute group bound to NUMA device nodes.
1471config HAVE_ARCH_NODE_DEV_GROUP
1472 bool
1473
eed9a328
YZ
1474config ARCH_HAS_NONLEAF_PMD_YOUNG
1475 bool
1476 help
1477 Architectures that select this option are capable of setting the
1478 accessed bit in non-leaf PMD entries when using them as part of linear
1479 address translations. Page table walkers that clear the accessed bit
1480 may use this capability to reduce their search space.
1481
2521f2c2 1482source "kernel/gcov/Kconfig"
45332b1b
MY
1483
1484source "scripts/gcc-plugins/Kconfig"
fa1b5d09 1485
d49a0626
PZ
1486config FUNCTION_ALIGNMENT_4B
1487 bool
1488
1489config FUNCTION_ALIGNMENT_8B
1490 bool
1491
1492config FUNCTION_ALIGNMENT_16B
1493 bool
1494
1495config FUNCTION_ALIGNMENT_32B
1496 bool
1497
1498config FUNCTION_ALIGNMENT_64B
1499 bool
1500
1501config FUNCTION_ALIGNMENT
1502 int
1503 default 64 if FUNCTION_ALIGNMENT_64B
1504 default 32 if FUNCTION_ALIGNMENT_32B
1505 default 16 if FUNCTION_ALIGNMENT_16B
1506 default 8 if FUNCTION_ALIGNMENT_8B
1507 default 4 if FUNCTION_ALIGNMENT_4B
1508 default 0
1509
22471e13 1510endmenu