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RISC-V: Drop invalid test from CONFIG_AS_HAS_OPTION_ARCH
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b2441318 1# SPDX-License-Identifier: GPL-2.0
fb32e03f
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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14config ARCH_HAS_SUBPAGE_FAULTS
15 bool
16 help
17 Select if the architecture can check permissions at sub-page
18 granularity (e.g. arm64 MTE). The probe_user_*() functions
19 must be implemented.
20
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TG
21config HOTPLUG_SMT
22 bool
23
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ME
24config SMT_NUM_THREADS_DYNAMIC
25 bool
26
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TG
27# Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLUG_CORE_SYNC_FULL
28config HOTPLUG_CORE_SYNC
29 bool
30
31# Basic CPU dead synchronization selected by architecture
32config HOTPLUG_CORE_SYNC_DEAD
33 bool
34 select HOTPLUG_CORE_SYNC
35
36# Full CPU synchronization with alive state selected by architecture
37config HOTPLUG_CORE_SYNC_FULL
38 bool
39 select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
40 select HOTPLUG_CORE_SYNC
41
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TG
42config HOTPLUG_SPLIT_STARTUP
43 bool
44 select HOTPLUG_CORE_SYNC_FULL
45
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TG
46config HOTPLUG_PARALLEL
47 bool
48 select HOTPLUG_SPLIT_STARTUP
49
142781e1 50config GENERIC_ENTRY
9f79ffc1 51 bool
142781e1 52
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MD
53config KPROBES
54 bool "Kprobes"
05ed160e 55 depends on MODULES
125e5645 56 depends on HAVE_KPROBES
05ed160e 57 select KALLSYMS
835f14ed 58 select TASKS_RCU if PREEMPTION
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MD
59 help
60 Kprobes allows you to trap at almost any kernel address and
61 execute a callback function. register_kprobe() establishes
62 a probepoint and specifies the callback. Kprobes is useful
63 for kernel debugging, non-intrusive instrumentation and testing.
64 If in doubt, say "N".
65
45f81b1c 66config JUMP_LABEL
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KK
67 bool "Optimize very unlikely/likely branches"
68 depends on HAVE_ARCH_JUMP_LABEL
4ab7674f 69 select OBJTOOL if HAVE_JUMP_LABEL_HACK
24b54fee 70 help
9f79ffc1
JH
71 This option enables a transparent branch optimization that
72 makes certain almost-always-true or almost-always-false branch
73 conditions even cheaper to execute within the kernel.
c5905afb 74
9f79ffc1
JH
75 Certain performance-sensitive kernel code, such as trace points,
76 scheduler functionality, networking code and KVM have such
77 branches and include support for this optimization technique.
c5905afb 78
9f79ffc1
JH
79 If it is detected that the compiler has support for "asm goto",
80 the kernel will compile such branches with just a nop
81 instruction. When the condition flag is toggled to true, the
82 nop will be converted to a jump instruction to execute the
83 conditional block of instructions.
c5905afb 84
9f79ffc1
JH
85 This technique lowers overhead and stress on the branch prediction
86 of the processor and generally makes the kernel faster. The update
87 of the condition is slower, but those are always very rare.
45f81b1c 88
9f79ffc1
JH
89 ( On 32-bit x86, the necessary options added to the compiler
90 flags may increase the size of the kernel slightly. )
45f81b1c 91
1987c947
PZ
92config STATIC_KEYS_SELFTEST
93 bool "Static key selftest"
94 depends on JUMP_LABEL
95 help
96 Boot time self-test of the branch patching code.
97
f03c4129
PZ
98config STATIC_CALL_SELFTEST
99 bool "Static call selftest"
100 depends on HAVE_STATIC_CALL
101 help
102 Boot time self-test of the call patching code.
103
afd66255 104config OPTPROBES
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MH
105 def_bool y
106 depends on KPROBES && HAVE_OPTPROBES
01b1d88b 107 select TASKS_RCU if PREEMPTION
afd66255 108
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MH
109config KPROBES_ON_FTRACE
110 def_bool y
111 depends on KPROBES && HAVE_KPROBES_ON_FTRACE
112 depends on DYNAMIC_FTRACE_WITH_REGS
113 help
9f79ffc1
JH
114 If function tracer is enabled and the arch supports full
115 passing of pt_regs to function tracing, then kprobes can
116 optimize on top of function tracing.
e7dbfe34 117
2b144498 118config UPROBES
09294e31 119 def_bool n
e8f4aa60 120 depends on ARCH_SUPPORTS_UPROBES
2b144498 121 help
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IM
122 Uprobes is the user-space counterpart to kprobes: they
123 enable instrumentation applications (such as 'perf probe')
124 to establish unintrusive probes in user-space binaries and
125 libraries, by executing handler functions when the probes
126 are hit by user-space applications.
127
128 ( These probes come in the form of single-byte breakpoints,
129 managed by the kernel and kept transparent to the probed
130 application. )
2b144498 131
adab66b7
SRV
132config HAVE_64BIT_ALIGNED_ACCESS
133 def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
134 help
135 Some architectures require 64 bit accesses to be 64 bit
136 aligned, which also requires structs containing 64 bit values
137 to be 64 bit aligned too. This includes some 32 bit
138 architectures which can do 64 bit accesses, as well as 64 bit
139 architectures without unaligned access.
140
141 This symbol should be selected by an architecture if 64 bit
142 accesses are required to be 64 bit aligned in this way even
143 though it is not a 64 bit architecture.
144
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145 See Documentation/core-api/unaligned-memory-access.rst for
146 more information on the topic of unaligned memory accesses.
adab66b7 147
58340a07 148config HAVE_EFFICIENT_UNALIGNED_ACCESS
9ba16087 149 bool
58340a07
JB
150 help
151 Some architectures are unable to perform unaligned accesses
152 without the use of get_unaligned/put_unaligned. Others are
153 unable to perform such accesses efficiently (e.g. trap on
154 unaligned access and require fixing it up in the exception
155 handler.)
156
157 This symbol should be selected by an architecture if it can
158 perform unaligned accesses efficiently to allow different
159 code paths to be selected for these cases. Some network
160 drivers, for example, could opt to not fix up alignment
161 problems with received packets if doing so would not help
162 much.
163
c9b54d6f 164 See Documentation/core-api/unaligned-memory-access.rst for more
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JB
165 information on the topic of unaligned memory accesses.
166
cf66bb93 167config ARCH_USE_BUILTIN_BSWAP
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168 bool
169 help
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JH
170 Modern versions of GCC (since 4.4) have builtin functions
171 for handling byte-swapping. Using these, instead of the old
172 inline assembler that the architecture code provides in the
173 __arch_bswapXX() macros, allows the compiler to see what's
174 happening and offers more opportunity for optimisation. In
175 particular, the compiler will be able to combine the byteswap
176 with a nearby load or store and use load-and-swap or
177 store-and-swap instructions if the architecture has them. It
178 should almost *never* result in code which is worse than the
179 hand-coded assembler in <asm/swab.h>. But just in case it
180 does, the use of the builtins is optional.
cf66bb93 181
9f79ffc1
JH
182 Any architecture with load-and-swap or store-and-swap
183 instructions should set this. And it shouldn't hurt to set it
184 on architectures that don't have such instructions.
cf66bb93 185
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AM
186config KRETPROBES
187 def_bool y
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MH
188 depends on KPROBES && (HAVE_KRETPROBES || HAVE_RETHOOK)
189
190config KRETPROBE_ON_RETHOOK
191 def_bool y
192 depends on HAVE_RETHOOK
193 depends on KRETPROBES
194 select RETHOOK
9edddaa2 195
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196config USER_RETURN_NOTIFIER
197 bool
198 depends on HAVE_USER_RETURN_NOTIFIER
199 help
200 Provide a kernel-internal notification when a cpu is about to
201 switch to user mode.
202
28b2ee20 203config HAVE_IOREMAP_PROT
9ba16087 204 bool
28b2ee20 205
125e5645 206config HAVE_KPROBES
9ba16087 207 bool
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AM
208
209config HAVE_KRETPROBES
9ba16087 210 bool
74bc7cee 211
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MH
212config HAVE_OPTPROBES
213 bool
d314d74c 214
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MH
215config HAVE_KPROBES_ON_FTRACE
216 bool
217
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218config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
219 bool
220 help
221 Since kretprobes modifies return address on the stack, the
222 stacktrace may see the kretprobe trampoline address instead
223 of correct one. If the architecture stacktrace code and
224 unwinder can adjust such entries, select this configuration.
225
540adea3 226config HAVE_FUNCTION_ERROR_INJECTION
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JB
227 bool
228
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229config HAVE_NMI
230 bool
231
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232config HAVE_FUNCTION_DESCRIPTORS
233 bool
234
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MY
235config TRACE_IRQFLAGS_SUPPORT
236 bool
237
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238config TRACE_IRQFLAGS_NMI_SUPPORT
239 bool
240
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241#
242# An arch should select this if it provides all these things:
243#
244# task_pt_regs() in asm/processor.h or asm/ptrace.h
245# arch_has_single_step() if there is hardware single-step support
246# arch_has_block_step() if there is hardware block-step support
1f5a4ad9
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247# asm/syscall.h supplying asm-generic/syscall.h interface
248# linux/regset.h user_regset interfaces
249# CORE_DUMP_USE_REGSET #define'd in linux/elf.h
153474ba 250# TIF_SYSCALL_TRACE calls ptrace_report_syscall_{entry,exit}
03248add 251# TIF_NOTIFY_RESUME calls resume_user_mode_work()
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RM
252#
253config HAVE_ARCH_TRACEHOOK
9ba16087 254 bool
1f5a4ad9 255
c64be2bb
MS
256config HAVE_DMA_CONTIGUOUS
257 bool
258
29d5e047 259config GENERIC_SMP_IDLE_THREAD
24b54fee 260 bool
29d5e047 261
485cf5da 262config GENERIC_IDLE_POLL_SETUP
24b54fee 263 bool
485cf5da 264
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265config ARCH_HAS_FORTIFY_SOURCE
266 bool
267 help
268 An architecture should select this when it can successfully
269 build and run with CONFIG_FORTIFY_SOURCE.
270
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CH
271#
272# Select if the arch provides a historic keepinit alias for the retain_initrd
273# command line option
274#
275config ARCH_HAS_KEEPINITRD
276 bool
277
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278# Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
279config ARCH_HAS_SET_MEMORY
280 bool
281
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RE
282# Select if arch has all set_direct_map_invalid/default() functions
283config ARCH_HAS_SET_DIRECT_MAP
284 bool
285
c30700db 286#
fa7e2247 287# Select if the architecture provides the arch_dma_set_uncached symbol to
a86ecfa6 288# either provide an uncached segment alias for a DMA allocation, or
fa7e2247 289# to remap the page tables in place.
c30700db 290#
fa7e2247 291config ARCH_HAS_DMA_SET_UNCACHED
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CH
292 bool
293
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CH
294#
295# Select if the architectures provides the arch_dma_clear_uncached symbol
296# to undo an in-place page table remap for uncached access.
297#
298config ARCH_HAS_DMA_CLEAR_UNCACHED
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CH
299 bool
300
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TG
301config ARCH_HAS_CPU_FINALIZE_INIT
302 bool
303
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JG
304# The architecture has a per-task state that includes the mm's PASID
305config ARCH_HAS_CPU_PASID
306 bool
307 select IOMMU_MM_DATA
308
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KC
309config HAVE_ARCH_THREAD_STRUCT_WHITELIST
310 bool
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KC
311 help
312 An architecture should select this to provide hardened usercopy
313 knowledge about what region of the thread_struct should be
314 whitelisted for copying to userspace. Normally this is only the
315 FPU registers. Specifically, arch_thread_struct_whitelist()
316 should be implemented. Without this, the entire thread_struct
317 field in task_struct will be left whitelisted.
318
5aaeb5c0
IM
319# Select if arch wants to size task_struct dynamically via arch_task_struct_size:
320config ARCH_WANTS_DYNAMIC_TASK_STRUCT
321 bool
322
51c2ee6d
ND
323config ARCH_WANTS_NO_INSTR
324 bool
325 help
326 An architecture should select this if the noinstr macro is being used on
327 functions to denote that the toolchain should avoid instrumenting such
328 functions and is required for correctness.
329
942fa985
YN
330config ARCH_32BIT_OFF_T
331 bool
332 depends on !64BIT
333 help
334 All new 32-bit architectures should have 64-bit off_t type on
335 userspace side which corresponds to the loff_t kernel type. This
336 is the requirement for modern ABIs. Some existing architectures
337 still support 32-bit off_t. This option is enabled for all such
338 architectures explicitly.
339
96c0a6a7
HC
340# Selected by 64 bit architectures which have a 32 bit f_tinode in struct ustat
341config ARCH_32BIT_USTAT_F_TINODE
342 bool
343
2ff2b7ec
MY
344config HAVE_ASM_MODVERSIONS
345 bool
346 help
a86ecfa6 347 This symbol should be selected by an architecture if it provides
2ff2b7ec
MY
348 <asm/asm-prototypes.h> to support the module versioning for symbols
349 exported from assembly code.
350
f850c30c
HC
351config HAVE_REGS_AND_STACK_ACCESS_API
352 bool
e01292b1 353 help
a86ecfa6 354 This symbol should be selected by an architecture if it supports
e01292b1
HC
355 the API needed to access registers and stack entries from pt_regs,
356 declared in asm/ptrace.h
357 For example the kprobes-based event tracer needs this API.
f850c30c 358
d7822b1e
MD
359config HAVE_RSEQ
360 bool
361 depends on HAVE_REGS_AND_STACK_ACCESS_API
362 help
363 This symbol should be selected by an architecture if it
364 supports an implementation of restartable sequences.
365
2f7ab126
MO
366config HAVE_RUST
367 bool
368 help
369 This symbol should be selected by an architecture if it
370 supports Rust.
371
3c88ee19
MH
372config HAVE_FUNCTION_ARG_ACCESS_API
373 bool
374 help
a86ecfa6 375 This symbol should be selected by an architecture if it supports
3c88ee19
MH
376 the API needed to access function arguments from pt_regs,
377 declared in asm/ptrace.h
378
62a038d3
P
379config HAVE_HW_BREAKPOINT
380 bool
99e8c5a3 381 depends on PERF_EVENTS
62a038d3 382
0102752e
FW
383config HAVE_MIXED_BREAKPOINTS_REGS
384 bool
385 depends on HAVE_HW_BREAKPOINT
386 help
387 Depending on the arch implementation of hardware breakpoints,
388 some of them have separate registers for data and instruction
389 breakpoints addresses, others have mixed registers to store
390 them but define the access type in a control register.
391 Select this option if your arch implements breakpoints under the
392 latter fashion.
393
7c68af6e
AK
394config HAVE_USER_RETURN_NOTIFIER
395 bool
a1922ed6 396
c01d4323
FW
397config HAVE_PERF_EVENTS_NMI
398 bool
23637d47
FW
399 help
400 System hardware can generate an NMI using the perf event
401 subsystem. Also has support for calculating CPU cycle events
402 to determine how many clock cycles in a given period.
c01d4323 403
05a4a952
NP
404config HAVE_HARDLOCKUP_DETECTOR_PERF
405 bool
406 depends on HAVE_PERF_EVENTS_NMI
407 help
408 The arch chooses to use the generic perf-NMI-based hardlockup
409 detector. Must define HAVE_PERF_EVENTS_NMI.
410
05a4a952
NP
411config HAVE_HARDLOCKUP_DETECTOR_ARCH
412 bool
05a4a952 413 help
1356d0b9
PM
414 The arch provides its own hardlockup detector implementation instead
415 of the generic ones.
416
417 It uses the same command line parameters, and sysctl interface,
418 as the generic hardlockup detectors.
05a4a952 419
c5e63197
JO
420config HAVE_PERF_REGS
421 bool
422 help
423 Support selective register dumps for perf events. This includes
424 bit-mapping of each registers and a unique architecture id.
425
c5ebcedb
JO
426config HAVE_PERF_USER_STACK_DUMP
427 bool
428 help
429 Support user stack dumps for perf event samples. This needs
430 access to the user stack pointer which is not unified across
431 architectures.
432
bf5438fc
JB
433config HAVE_ARCH_JUMP_LABEL
434 bool
435
50ff18ab
AB
436config HAVE_ARCH_JUMP_LABEL_RELATIVE
437 bool
438
0d6e24d4
PZ
439config MMU_GATHER_TABLE_FREE
440 bool
441
ff2e6d72 442config MMU_GATHER_RCU_TABLE_FREE
26723911 443 bool
0d6e24d4 444 select MMU_GATHER_TABLE_FREE
26723911 445
3af4bd03 446config MMU_GATHER_PAGE_SIZE
ed6a7935
PZ
447 bool
448
27796d03
PZ
449config MMU_GATHER_NO_RANGE
450 bool
1e9fdf21
PZ
451 select MMU_GATHER_MERGE_VMAS
452
453config MMU_GATHER_NO_FLUSH_CACHE
454 bool
455
456config MMU_GATHER_MERGE_VMAS
457 bool
27796d03 458
580a586c 459config MMU_GATHER_NO_GATHER
952a31c9 460 bool
0d6e24d4 461 depends on MMU_GATHER_TABLE_FREE
952a31c9 462
d53c3dfb
NP
463config ARCH_WANT_IRQS_OFF_ACTIVATE_MM
464 bool
465 help
466 Temporary select until all architectures can be converted to have
467 irqs disabled over activate_mm. Architectures that do IPI based TLB
468 shootdowns should enable this.
469
88e3009b
NP
470# Use normal mm refcounting for MMU_LAZY_TLB kernel thread references.
471# MMU_LAZY_TLB_REFCOUNT=n can improve the scalability of context switching
472# to/from kernel threads when the same mm is running on a lot of CPUs (a large
473# multi-threaded application), by reducing contention on the mm refcount.
474#
475# This can be disabled if the architecture ensures no CPUs are using an mm as a
476# "lazy tlb" beyond its final refcount (i.e., by the time __mmdrop frees the mm
477# or its kernel page tables). This could be arranged by arch_exit_mmap(), or
478# final exit(2) TLB flush, for example.
479#
480# To implement this, an arch *must*:
481# Ensure the _lazy_tlb variants of mmgrab/mmdrop are used when manipulating
482# the lazy tlb reference of a kthread's ->active_mm (non-arch code has been
483# converted already).
484config MMU_LAZY_TLB_REFCOUNT
485 def_bool y
2655421a
NP
486 depends on !MMU_LAZY_TLB_SHOOTDOWN
487
488# This option allows MMU_LAZY_TLB_REFCOUNT=n. It ensures no CPUs are using an
489# mm as a lazy tlb beyond its last reference count, by shooting down these
490# users before the mm is deallocated. __mmdrop() first IPIs all CPUs that may
491# be using the mm as a lazy tlb, so that they may switch themselves to using
492# init_mm for their active mm. mm_cpumask(mm) is used to determine which CPUs
493# may be using mm as a lazy tlb mm.
494#
495# To implement this, an arch *must*:
496# - At the time of the final mmdrop of the mm, ensure mm_cpumask(mm) contains
497# at least all possible CPUs in which the mm is lazy.
498# - It must meet the requirements for MMU_LAZY_TLB_REFCOUNT=n (see above).
499config MMU_LAZY_TLB_SHOOTDOWN
500 bool
88e3009b 501
df013ffb
YH
502config ARCH_HAVE_NMI_SAFE_CMPXCHG
503 bool
504
2e83b879
PM
505config ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
506 bool
507
43570fd2
HC
508config HAVE_ALIGNED_STRUCT_PAGE
509 bool
510 help
511 This makes sure that struct pages are double word aligned and that
512 e.g. the SLUB allocator can perform double word atomic operations
513 on a struct page for better performance. However selecting this
514 might increase the size of a struct page by a word.
515
4156153c
HC
516config HAVE_CMPXCHG_LOCAL
517 bool
518
2565409f
HC
519config HAVE_CMPXCHG_DOUBLE
520 bool
521
77e58496
PM
522config ARCH_WEAK_RELEASE_ACQUIRE
523 bool
524
c1d7e01d
WD
525config ARCH_WANT_IPC_PARSE_VERSION
526 bool
527
528config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
529 bool
530
48b25c43 531config ARCH_WANT_OLD_COMPAT_IPC
c1d7e01d 532 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
48b25c43
CM
533 bool
534
282a181b
YZ
535config HAVE_ARCH_SECCOMP
536 bool
537 help
538 An arch should select this symbol to support seccomp mode 1 (the fixed
539 syscall policy), and must provide an overrides for __NR_seccomp_sigreturn,
540 and compat syscalls if the asm-generic/seccomp.h defaults need adjustment:
541 - __NR_seccomp_read_32
542 - __NR_seccomp_write_32
543 - __NR_seccomp_exit_32
544 - __NR_seccomp_sigreturn_32
545
e2cfabdf
WD
546config HAVE_ARCH_SECCOMP_FILTER
547 bool
282a181b 548 select HAVE_ARCH_SECCOMP
e2cfabdf 549 help
fb0fadf9 550 An arch should select this symbol if it provides all of these things:
282a181b 551 - all the requirements for HAVE_ARCH_SECCOMP
bb6ea430
WD
552 - syscall_get_arch()
553 - syscall_get_arguments()
554 - syscall_rollback()
555 - syscall_set_return_value()
fb0fadf9
WD
556 - SIGSYS siginfo_t support
557 - secure_computing is called from a ptrace_event()-safe context
558 - secure_computing return value is checked and a return value of -1
559 results in the system call being skipped immediately.
48dc92b9 560 - seccomp syscall wired up
0d8315dd
YZ
561 - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE,
562 SECCOMP_ARCH_NATIVE_NR, SECCOMP_ARCH_NATIVE_NAME defined. If
563 COMPAT is supported, have the SECCOMP_ARCH_COMPAT* defines too.
e2cfabdf 564
282a181b
YZ
565config SECCOMP
566 prompt "Enable seccomp to safely execute untrusted bytecode"
567 def_bool y
568 depends on HAVE_ARCH_SECCOMP
569 help
570 This kernel feature is useful for number crunching applications
571 that may need to handle untrusted bytecode during their
572 execution. By using pipes or other transports made available
573 to the process as file descriptors supporting the read/write
574 syscalls, it's possible to isolate those applications in their
575 own address space using seccomp. Once seccomp is enabled via
576 prctl(PR_SET_SECCOMP) or the seccomp() syscall, it cannot be
577 disabled and the task is only allowed to execute a few safe
578 syscalls defined by each seccomp mode.
579
580 If unsure, say Y.
581
e2cfabdf
WD
582config SECCOMP_FILTER
583 def_bool y
584 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
585 help
586 Enable tasks to build secure computing environments defined
587 in terms of Berkeley Packet Filter programs which implement
588 task-defined system call filtering polices.
589
5fb94e9c 590 See Documentation/userspace-api/seccomp_filter.rst for details.
e2cfabdf 591
0d8315dd
YZ
592config SECCOMP_CACHE_DEBUG
593 bool "Show seccomp filter cache status in /proc/pid/seccomp_cache"
594 depends on SECCOMP_FILTER && !HAVE_SPARSE_SYSCALL_NR
595 depends on PROC_FS
596 help
597 This enables the /proc/pid/seccomp_cache interface to monitor
598 seccomp cache data. The file format is subject to change. Reading
599 the file requires CAP_SYS_ADMIN.
600
601 This option is for debugging only. Enabling presents the risk that
602 an adversary may be able to infer the seccomp filter logic.
603
604 If unsure, say N.
605
afaef01c
AP
606config HAVE_ARCH_STACKLEAK
607 bool
608 help
609 An architecture should select this if it has the code which
610 fills the used part of the kernel stack with the STACKLEAK_POISON
611 value before returning from system calls.
612
d148eac0 613config HAVE_STACKPROTECTOR
19952a92
KC
614 bool
615 help
616 An arch should select this symbol if:
19952a92
KC
617 - it has implemented a stack canary (e.g. __stack_chk_guard)
618
050e9baa 619config STACKPROTECTOR
2a61f474 620 bool "Stack Protector buffer overflow detection"
d148eac0 621 depends on HAVE_STACKPROTECTOR
2a61f474
MY
622 depends on $(cc-option,-fstack-protector)
623 default y
19952a92 624 help
8779657d 625 This option turns on the "stack-protector" GCC feature. This
19952a92
KC
626 feature puts, at the beginning of functions, a canary value on
627 the stack just before the return address, and validates
628 the value just before actually returning. Stack based buffer
629 overflows (that need to overwrite this return address) now also
630 overwrite the canary, which gets detected and the attack is then
631 neutralized via a kernel panic.
632
8779657d
KC
633 Functions will have the stack-protector canary logic added if they
634 have an 8-byte or larger character array on the stack.
635
19952a92 636 This feature requires gcc version 4.2 or above, or a distribution
8779657d
KC
637 gcc with the feature backported ("-fstack-protector").
638
639 On an x86 "defconfig" build, this feature adds canary checks to
640 about 3% of all kernel functions, which increases kernel code size
641 by about 0.3%.
642
050e9baa 643config STACKPROTECTOR_STRONG
2a61f474 644 bool "Strong Stack Protector"
050e9baa 645 depends on STACKPROTECTOR
2a61f474
MY
646 depends on $(cc-option,-fstack-protector-strong)
647 default y
8779657d
KC
648 help
649 Functions will have the stack-protector canary logic added in any
650 of the following conditions:
651
652 - local variable's address used as part of the right hand side of an
653 assignment or function argument
654 - local variable is an array (or union containing an array),
655 regardless of array type or length
656 - uses register local variables
657
658 This feature requires gcc version 4.9 or above, or a distribution
659 gcc with the feature backported ("-fstack-protector-strong").
660
661 On an x86 "defconfig" build, this feature adds canary checks to
662 about 20% of all kernel functions, which increases the kernel code
663 size by about 2%.
664
d08b9f0c
ST
665config ARCH_SUPPORTS_SHADOW_CALL_STACK
666 bool
667 help
afcf5441
DL
668 An architecture should select this if it supports the compiler's
669 Shadow Call Stack and implements runtime support for shadow stack
aa7a65ae 670 switching.
d08b9f0c
ST
671
672config SHADOW_CALL_STACK
afcf5441
DL
673 bool "Shadow Call Stack"
674 depends on ARCH_SUPPORTS_SHADOW_CALL_STACK
38792972 675 depends on DYNAMIC_FTRACE_WITH_ARGS || DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER
d08b9f0c 676 help
afcf5441
DL
677 This option enables the compiler's Shadow Call Stack, which
678 uses a shadow stack to protect function return addresses from
679 being overwritten by an attacker. More information can be found
680 in the compiler's documentation:
d08b9f0c 681
afcf5441
DL
682 - Clang: https://clang.llvm.org/docs/ShadowCallStack.html
683 - GCC: https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options
d08b9f0c
ST
684
685 Note that security guarantees in the kernel differ from the
686 ones documented for user space. The kernel must store addresses
687 of shadow stacks in memory, which means an attacker capable of
688 reading and writing arbitrary memory may be able to locate them
689 and hijack control flow by modifying the stacks.
690
9beccca0
AB
691config DYNAMIC_SCS
692 bool
693 help
694 Set by the arch code if it relies on code patching to insert the
695 shadow call stack push and pop instructions rather than on the
696 compiler.
697
dc5723b0
ST
698config LTO
699 bool
700 help
701 Selected if the kernel will be built using the compiler's LTO feature.
702
703config LTO_CLANG
704 bool
705 select LTO
706 help
707 Selected if the kernel will be built using Clang's LTO feature.
708
709config ARCH_SUPPORTS_LTO_CLANG
710 bool
711 help
712 An architecture should select this option if it supports:
713 - compiling with Clang,
714 - compiling inline assembly with Clang's integrated assembler,
715 - and linking with LLD.
716
717config ARCH_SUPPORTS_LTO_CLANG_THIN
718 bool
719 help
720 An architecture should select this option if it can support Clang's
721 ThinLTO mode.
722
723config HAS_LTO_CLANG
724 def_bool y
1e68a8af 725 depends on CC_IS_CLANG && LD_IS_LLD && AS_IS_LLVM
dc5723b0
ST
726 depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
727 depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
728 depends on ARCH_SUPPORTS_LTO_CLANG
729 depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT
349fde59
JK
730 # https://github.com/ClangBuiltLinux/linux/issues/1721
731 depends on (!KASAN || KASAN_HW_TAGS || CLANG_VERSION >= 170000) || !DEBUG_INFO
732 depends on (!KCOV || CLANG_VERSION >= 170000) || !DEBUG_INFO
dc5723b0 733 depends on !GCOV_KERNEL
dc5723b0
ST
734 help
735 The compiler and Kconfig options support building with Clang's
736 LTO.
737
738choice
739 prompt "Link Time Optimization (LTO)"
740 default LTO_NONE
741 help
742 This option enables Link Time Optimization (LTO), which allows the
743 compiler to optimize binaries globally.
744
745 If unsure, select LTO_NONE. Note that LTO is very resource-intensive
746 so it's disabled by default.
747
748config LTO_NONE
749 bool "None"
750 help
751 Build the kernel normally, without Link Time Optimization (LTO).
752
753config LTO_CLANG_FULL
754 bool "Clang Full LTO (EXPERIMENTAL)"
755 depends on HAS_LTO_CLANG
756 depends on !COMPILE_TEST
757 select LTO_CLANG
758 help
9f79ffc1
JH
759 This option enables Clang's full Link Time Optimization (LTO), which
760 allows the compiler to optimize the kernel globally. If you enable
761 this option, the compiler generates LLVM bitcode instead of ELF
762 object files, and the actual compilation from bitcode happens at
763 the LTO link step, which may take several minutes depending on the
764 kernel configuration. More information can be found from LLVM's
765 documentation:
dc5723b0
ST
766
767 https://llvm.org/docs/LinkTimeOptimization.html
768
769 During link time, this option can use a large amount of RAM, and
770 may take much longer than the ThinLTO option.
771
772config LTO_CLANG_THIN
773 bool "Clang ThinLTO (EXPERIMENTAL)"
774 depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN
775 select LTO_CLANG
776 help
777 This option enables Clang's ThinLTO, which allows for parallel
778 optimization and faster incremental compiles compared to the
779 CONFIG_LTO_CLANG_FULL option. More information can be found
780 from Clang's documentation:
781
782 https://clang.llvm.org/docs/ThinLTO.html
783
784 If unsure, say Y.
785endchoice
786
cf68fffb
ST
787config ARCH_SUPPORTS_CFI_CLANG
788 bool
789 help
790 An architecture should select this option if it can support Clang's
791 Control-Flow Integrity (CFI) checking.
792
89245600
ST
793config ARCH_USES_CFI_TRAPS
794 bool
795
cf68fffb
ST
796config CFI_CLANG
797 bool "Use Clang's Control Flow Integrity (CFI)"
89245600
ST
798 depends on ARCH_SUPPORTS_CFI_CLANG
799 depends on $(cc-option,-fsanitize=kcfi)
cf68fffb
ST
800 help
801 This option enables Clang’s forward-edge Control Flow Integrity
802 (CFI) checking, where the compiler injects a runtime check to each
803 indirect function call to ensure the target is a valid function with
804 the correct static type. This restricts possible call targets and
805 makes it more difficult for an attacker to exploit bugs that allow
806 the modification of stored function pointers. More information can be
807 found from Clang's documentation:
808
809 https://clang.llvm.org/docs/ControlFlowIntegrity.html
810
cf68fffb
ST
811config CFI_PERMISSIVE
812 bool "Use CFI in permissive mode"
813 depends on CFI_CLANG
814 help
815 When selected, Control Flow Integrity (CFI) violations result in a
816 warning instead of a kernel panic. This option should only be used
817 for finding indirect call type mismatches during development.
818
819 If unsure, say N.
820
0f60a8ef
KC
821config HAVE_ARCH_WITHIN_STACK_FRAMES
822 bool
823 help
824 An architecture should select this if it can walk the kernel stack
825 frames to determine if an object is part of either the arguments
826 or local variables (i.e. that it excludes saved return addresses,
827 and similar) by implementing an inline arch_within_stack_frames(),
828 which is used by CONFIG_HARDENED_USERCOPY.
829
24a9c541 830config HAVE_CONTEXT_TRACKING_USER
2b1d5024
FW
831 bool
832 help
91d1aa43
FW
833 Provide kernel/user boundaries probes necessary for subsystems
834 that need it, such as userspace RCU extended quiescent state.
490f561b
FW
835 Syscalls need to be wrapped inside user_exit()-user_enter(), either
836 optimized behind static key or through the slow path using TIF_NOHZ
837 flag. Exceptions handlers must be wrapped as well. Irqs are already
6f0e6c15 838 protected inside ct_irq_enter/ct_irq_exit() but preemption or signal
490f561b
FW
839 handling on irq exit still need to be protected.
840
24a9c541 841config HAVE_CONTEXT_TRACKING_USER_OFFSTACK
83c2da2e
FW
842 bool
843 help
844 Architecture neither relies on exception_enter()/exception_exit()
845 nor on schedule_user(). Also preempt_schedule_notrace() and
846 preempt_schedule_irq() can't be called in a preemptible section
847 while context tracking is CONTEXT_USER. This feature reflects a sane
848 entry implementation where the following requirements are met on
849 critical entry code, ie: before user_exit() or after user_enter():
850
851 - Critical entry code isn't preemptible (or better yet:
852 not interruptible).
493c1822 853 - No use of RCU read side critical sections, unless ct_nmi_enter()
83c2da2e
FW
854 got called.
855 - No use of instrumentation, unless instrumentation_begin() got
856 called.
857
490f561b
FW
858config HAVE_TIF_NOHZ
859 bool
860 help
861 Arch relies on TIF_NOHZ and syscall slow path to implement context
862 tracking calls to user_enter()/user_exit().
2b1d5024 863
b952741c
FW
864config HAVE_VIRT_CPU_ACCOUNTING
865 bool
866
2b91ec9f
FW
867config HAVE_VIRT_CPU_ACCOUNTING_IDLE
868 bool
869 help
870 Architecture has its own way to account idle CPU time and therefore
871 doesn't implement vtime_account_idle().
872
40565b5a
SG
873config ARCH_HAS_SCALED_CPUTIME
874 bool
875
554b0004
KH
876config HAVE_VIRT_CPU_ACCOUNTING_GEN
877 bool
878 default y if 64BIT
879 help
880 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
881 Before enabling this option, arch code must be audited
882 to ensure there are no races in concurrent read/write of
883 cputime_t. For example, reading/writing 64-bit cputime_t on
884 some 32-bit arches may require multiple accesses, so proper
885 locking is needed to protect against concurrent accesses.
886
fdf9c356
FW
887config HAVE_IRQ_TIME_ACCOUNTING
888 bool
889 help
890 Archs need to ensure they use a high enough resolution clock to
891 support irq time accounting and then call enable_sched_clock_irqtime().
892
c49dd340
KS
893config HAVE_MOVE_PUD
894 bool
895 help
896 Architectures that select this are able to move page tables at the
897 PUD level. If there are only 3 page table levels, the move effectively
898 happens at the PGD level.
899
2c91bd4a
JFG
900config HAVE_MOVE_PMD
901 bool
902 help
903 Archs that select this are able to move page tables at the PMD level.
904
15626062
GS
905config HAVE_ARCH_TRANSPARENT_HUGEPAGE
906 bool
907
a00cc7d9
MW
908config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
909 bool
910
0ddab1d2
TK
911config HAVE_ARCH_HUGE_VMAP
912 bool
913
121e6f32
NP
914#
915# Archs that select this would be capable of PMD-sized vmaps (i.e.,
559089e0
SL
916# arch_vmap_pmd_supported() returns true). The VM_ALLOW_HUGE_VMAP flag
917# must be used to enable allocations to use hugepages.
121e6f32
NP
918#
919config HAVE_ARCH_HUGE_VMALLOC
920 depends on HAVE_ARCH_HUGE_VMAP
921 bool
922
3876d4a3
AG
923config ARCH_WANT_HUGE_PMD_SHARE
924 bool
925
2f0584f3
RE
926# Archs that want to use pmd_mkwrite on kernel memory need it defined even
927# if there are no userspace memory management features that use it
928config ARCH_WANT_KERNEL_PMD_MKWRITE
929 bool
930
931config ARCH_WANT_PMD_MKWRITE
932 def_bool TRANSPARENT_HUGEPAGE || ARCH_WANT_KERNEL_PMD_MKWRITE
933
0f8975ec
PE
934config HAVE_ARCH_SOFT_DIRTY
935 bool
936
786d35d4
DH
937config HAVE_MOD_ARCH_SPECIFIC
938 bool
939 help
940 The arch uses struct mod_arch_specific to store data. Many arches
941 just need a simple module loader without arch specific data - those
942 should not enable this.
943
944config MODULES_USE_ELF_RELA
945 bool
946 help
947 Modules only use ELF RELA relocations. Modules with ELF REL
948 relocations will give an error.
949
950config MODULES_USE_ELF_REL
951 bool
952 help
953 Modules only use ELF REL relocations. Modules with ELF RELA
954 relocations will give an error.
955
01dc0386
CL
956config ARCH_WANTS_MODULES_DATA_IN_VMALLOC
957 bool
958 help
959 For architectures like powerpc/32 which have constraints on module
960 allocation and need to allocate module data outside of module area.
961
cc1f0274
FW
962config HAVE_IRQ_EXIT_ON_IRQ_STACK
963 bool
964 help
965 Architecture doesn't only execute the irq handler on the irq stack
966 but also irq_exit(). This way we can process softirqs on this irq
967 stack instead of switching to a new one when we call __do_softirq()
968 in the end of an hardirq.
969 This spares a stack switch and improves cache usage on softirq
970 processing.
971
cd1a41ce
TG
972config HAVE_SOFTIRQ_ON_OWN_STACK
973 bool
974 help
975 Architecture provides a function to run __do_softirq() on a
c226bc3c 976 separate stack.
cd1a41ce 977
8cbb2b50
SAS
978config SOFTIRQ_ON_OWN_STACK
979 def_bool HAVE_SOFTIRQ_ON_OWN_STACK && !PREEMPT_RT
980
12700c17
AB
981config ALTERNATE_USER_ADDRESS_SPACE
982 bool
983 help
984 Architectures set this when the CPU uses separate address
985 spaces for kernel and user space pointers. In this case, the
986 access_ok() check on a __user pointer is skipped.
987
235a8f02
KS
988config PGTABLE_LEVELS
989 int
990 default 2
991
2b68f6ca
KC
992config ARCH_HAS_ELF_RANDOMIZE
993 bool
994 help
995 An architecture supports choosing randomized locations for
996 stack, mmap, brk, and ET_DYN. Defined functions:
997 - arch_mmap_rnd()
204db6ed 998 - arch_randomize_brk()
2b68f6ca 999
d07e2259
DC
1000config HAVE_ARCH_MMAP_RND_BITS
1001 bool
1002 help
1003 An arch should select this symbol if it supports setting a variable
1004 number of bits for use in establishing the base address for mmap
1005 allocations, has MMU enabled and provides values for both:
1006 - ARCH_MMAP_RND_BITS_MIN
1007 - ARCH_MMAP_RND_BITS_MAX
1008
5f56a5df
JS
1009config HAVE_EXIT_THREAD
1010 bool
1011 help
1012 An architecture implements exit_thread.
1013
d07e2259
DC
1014config ARCH_MMAP_RND_BITS_MIN
1015 int
1016
1017config ARCH_MMAP_RND_BITS_MAX
1018 int
1019
1020config ARCH_MMAP_RND_BITS_DEFAULT
1021 int
1022
1023config ARCH_MMAP_RND_BITS
1024 int "Number of bits to use for ASLR of mmap base address" if EXPERT
1025 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
1026 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
1027 default ARCH_MMAP_RND_BITS_MIN
1028 depends on HAVE_ARCH_MMAP_RND_BITS
1029 help
1030 This value can be used to select the number of bits to use to
1031 determine the random offset to the base address of vma regions
1032 resulting from mmap allocations. This value will be bounded
1033 by the architecture's minimum and maximum supported values.
1034
1035 This value can be changed after boot using the
1036 /proc/sys/vm/mmap_rnd_bits tunable
1037
1038config HAVE_ARCH_MMAP_RND_COMPAT_BITS
1039 bool
1040 help
1041 An arch should select this symbol if it supports running applications
1042 in compatibility mode, supports setting a variable number of bits for
1043 use in establishing the base address for mmap allocations, has MMU
1044 enabled and provides values for both:
1045 - ARCH_MMAP_RND_COMPAT_BITS_MIN
1046 - ARCH_MMAP_RND_COMPAT_BITS_MAX
1047
1048config ARCH_MMAP_RND_COMPAT_BITS_MIN
1049 int
1050
1051config ARCH_MMAP_RND_COMPAT_BITS_MAX
1052 int
1053
1054config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1055 int
1056
1057config ARCH_MMAP_RND_COMPAT_BITS
1058 int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
1059 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
1060 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1061 default ARCH_MMAP_RND_COMPAT_BITS_MIN
1062 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
1063 help
1064 This value can be used to select the number of bits to use to
1065 determine the random offset to the base address of vma regions
1066 resulting from mmap allocations for compatible applications This
1067 value will be bounded by the architecture's minimum and maximum
1068 supported values.
1069
1070 This value can be changed after boot using the
1071 /proc/sys/vm/mmap_rnd_compat_bits tunable
1072
1b028f78
DS
1073config HAVE_ARCH_COMPAT_MMAP_BASES
1074 bool
1075 help
1076 This allows 64bit applications to invoke 32-bit mmap() syscall
1077 and vice-versa 32-bit applications to call 64-bit mmap().
1078 Required for applications doing different bitness syscalls.
1079
1f0e290c
GR
1080config PAGE_SIZE_LESS_THAN_64KB
1081 def_bool y
1082 depends on !ARM64_64K_PAGES
1f0e290c
GR
1083 depends on !PAGE_SIZE_64KB
1084 depends on !PARISC_PAGE_SIZE_64KB
e4bbd20d
NC
1085 depends on PAGE_SIZE_LESS_THAN_256KB
1086
1087config PAGE_SIZE_LESS_THAN_256KB
1088 def_bool y
1f0e290c
GR
1089 depends on !PAGE_SIZE_256KB
1090
67f3977f
AG
1091# This allows to use a set of generic functions to determine mmap base
1092# address by giving priority to top-down scheme only if the process
1093# is not in legacy mode (compat task, unlimited stack size or
1094# sysctl_legacy_va_layout).
1095# Architecture that selects this option can provide its own version of:
1096# - STACK_RND_MASK
1097config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
1098 bool
1099 depends on MMU
e7142bf5 1100 select ARCH_HAS_ELF_RANDOMIZE
67f3977f 1101
03f16cd0
JP
1102config HAVE_OBJTOOL
1103 bool
1104
4ab7674f
JP
1105config HAVE_JUMP_LABEL_HACK
1106 bool
1107
22102f45
JP
1108config HAVE_NOINSTR_HACK
1109 bool
1110
489e355b
JP
1111config HAVE_NOINSTR_VALIDATION
1112 bool
1113
5f3da8c0
JP
1114config HAVE_UACCESS_VALIDATION
1115 bool
1116 select OBJTOOL
1117
b9ab5ebb
JP
1118config HAVE_STACK_VALIDATION
1119 bool
1120 help
03f16cd0
JP
1121 Architecture supports objtool compile-time frame pointer rule
1122 validation.
b9ab5ebb 1123
af085d90
JP
1124config HAVE_RELIABLE_STACKTRACE
1125 bool
1126 help
140d7e88
MB
1127 Architecture has either save_stack_trace_tsk_reliable() or
1128 arch_stack_walk_reliable() function which only returns a stack trace
1129 if it can guarantee the trace is reliable.
af085d90 1130
468a9428
GS
1131config HAVE_ARCH_HASH
1132 bool
1133 default n
1134 help
1135 If this is set, the architecture provides an <asm/hash.h>
1136 file which provides platform-specific implementations of some
1137 functions in <linux/hash.h> or fs/namei.c.
1138
666047fe
FT
1139config HAVE_ARCH_NVRAM_OPS
1140 bool
1141
3a495511
WBG
1142config ISA_BUS_API
1143 def_bool ISA
1144
d2125043
AV
1145#
1146# ABI hall of shame
1147#
1148config CLONE_BACKWARDS
1149 bool
1150 help
1151 Architecture has tls passed as the 4th argument of clone(2),
1152 not the 5th one.
1153
1154config CLONE_BACKWARDS2
1155 bool
1156 help
1157 Architecture has the first two arguments of clone(2) swapped.
1158
dfa9771a
MS
1159config CLONE_BACKWARDS3
1160 bool
1161 help
1162 Architecture has tls passed as the 3rd argument of clone(2),
1163 not the 5th one.
1164
eaca6eae
AV
1165config ODD_RT_SIGACTION
1166 bool
1167 help
1168 Architecture has unusual rt_sigaction(2) arguments
1169
0a0e8cdf
AV
1170config OLD_SIGSUSPEND
1171 bool
1172 help
1173 Architecture has old sigsuspend(2) syscall, of one-argument variety
1174
1175config OLD_SIGSUSPEND3
1176 bool
1177 help
1178 Even weirder antique ABI - three-argument sigsuspend(2)
1179
495dfbf7
AV
1180config OLD_SIGACTION
1181 bool
1182 help
1183 Architecture has old sigaction(2) syscall. Nope, not the same
1184 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
1185 but fairly different variant of sigaction(2), thanks to OSF/1
1186 compatibility...
1187
1188config COMPAT_OLD_SIGACTION
1189 bool
1190
17435e5f 1191config COMPAT_32BIT_TIME
942437c9
AB
1192 bool "Provide system calls for 32-bit time_t"
1193 default !64BIT || COMPAT
17435e5f
DD
1194 help
1195 This enables 32 bit time_t support in addition to 64 bit time_t support.
1196 This is relevant on all 32-bit architectures, and 64-bit architectures
1197 as part of compat syscall handling.
1198
87a4c375
CH
1199config ARCH_NO_PREEMPT
1200 bool
1201
a50a3f4b
TG
1202config ARCH_SUPPORTS_RT
1203 bool
1204
fff7fb0b
ZZ
1205config CPU_NO_EFFICIENT_FFS
1206 def_bool n
1207
ba14a194
AL
1208config HAVE_ARCH_VMAP_STACK
1209 def_bool n
1210 help
1211 An arch should select this symbol if it can support kernel stacks
1212 in vmalloc space. This means:
1213
1214 - vmalloc space must be large enough to hold many kernel stacks.
1215 This may rule out many 32-bit architectures.
1216
1217 - Stacks in vmalloc space need to work reliably. For example, if
1218 vmap page tables are created on demand, either this mechanism
1219 needs to work while the stack points to a virtual address with
1220 unpopulated page tables or arch code (switch_to() and switch_mm(),
1221 most likely) needs to ensure that the stack's page table entries
1222 are populated before running on a possibly unpopulated stack.
1223
1224 - If the stack overflows into a guard page, something reasonable
1225 should happen. The definition of "reasonable" is flexible, but
1226 instantly rebooting without logging anything would be unfriendly.
1227
1228config VMAP_STACK
1229 default y
1230 bool "Use a virtually-mapped stack"
eafb149e 1231 depends on HAVE_ARCH_VMAP_STACK
38dd767d 1232 depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC
a7f7f624 1233 help
ba14a194
AL
1234 Enable this if you want the use virtually-mapped kernel stacks
1235 with guard pages. This causes kernel stack overflows to be
1236 caught immediately rather than causing difficult-to-diagnose
1237 corruption.
1238
38dd767d
AK
1239 To use this with software KASAN modes, the architecture must support
1240 backing virtual mappings with real shadow memory, and KASAN_VMALLOC
1241 must be enabled.
ba14a194 1242
39218ff4
KC
1243config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
1244 def_bool n
1245 help
1246 An arch should select this symbol if it can support kernel stack
1247 offset randomization with calls to add_random_kstack_offset()
1248 during syscall entry and choose_random_kstack_offset() during
1249 syscall exit. Careful removal of -fstack-protector-strong and
1250 -fstack-protector should also be applied to the entry code and
1251 closely examined, as the artificial stack bump looks like an array
1252 to the compiler, so it will attempt to add canary checks regardless
1253 of the static branch state.
1254
8cb37a59
ME
1255config RANDOMIZE_KSTACK_OFFSET
1256 bool "Support for randomizing kernel stack offset on syscall entry" if EXPERT
1257 default y
39218ff4 1258 depends on HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
efa90c11 1259 depends on INIT_STACK_NONE || !CC_IS_CLANG || CLANG_VERSION >= 140000
39218ff4
KC
1260 help
1261 The kernel stack offset can be randomized (after pt_regs) by
1262 roughly 5 bits of entropy, frustrating memory corruption
1263 attacks that depend on stack address determinism or
8cb37a59
ME
1264 cross-syscall address exposures.
1265
1266 The feature is controlled via the "randomize_kstack_offset=on/off"
1267 kernel boot param, and if turned off has zero overhead due to its use
1268 of static branches (see JUMP_LABEL).
1269
1270 If unsure, say Y.
1271
1272config RANDOMIZE_KSTACK_OFFSET_DEFAULT
1273 bool "Default state of kernel stack offset randomization"
1274 depends on RANDOMIZE_KSTACK_OFFSET
1275 help
1276 Kernel stack offset randomization is controlled by kernel boot param
1277 "randomize_kstack_offset=on/off", and this config chooses the default
1278 boot state.
39218ff4 1279
ad21fc4f
LA
1280config ARCH_OPTIONAL_KERNEL_RWX
1281 def_bool n
1282
1283config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1284 def_bool n
1285
1286config ARCH_HAS_STRICT_KERNEL_RWX
1287 def_bool n
1288
0f5bf6d0 1289config STRICT_KERNEL_RWX
ad21fc4f
LA
1290 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
1291 depends on ARCH_HAS_STRICT_KERNEL_RWX
1292 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1293 help
1294 If this is set, kernel text and rodata memory will be made read-only,
1295 and non-text memory will be made non-executable. This provides
1296 protection against certain security exploits (e.g. executing the heap
1297 or modifying text)
1298
1299 These features are considered standard security practice these days.
1300 You should say Y here in almost all cases.
1301
1302config ARCH_HAS_STRICT_MODULE_RWX
1303 def_bool n
1304
0f5bf6d0 1305config STRICT_MODULE_RWX
ad21fc4f
LA
1306 bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX
1307 depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES
1308 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1309 help
1310 If this is set, module text and rodata memory will be made read-only,
1311 and non-text memory will be made non-executable. This provides
1312 protection against certain security exploits (e.g. writing to text)
1313
ea8c64ac
CH
1314# select if the architecture provides an asm/dma-direct.h header
1315config ARCH_HAS_PHYS_TO_DMA
1316 bool
1317
04f264d3
PB
1318config HAVE_ARCH_COMPILER_H
1319 bool
1320 help
1321 An architecture can select this if it provides an
1322 asm/compiler.h header that should be included after
1323 linux/compiler-*.h in order to override macro definitions that those
1324 headers generally provide.
1325
271ca788
AB
1326config HAVE_ARCH_PREL32_RELOCATIONS
1327 bool
1328 help
1329 May be selected by an architecture if it supports place-relative
1330 32-bit relocations, both in the toolchain and in the module loader,
1331 in which case relative references can be used in special sections
1332 for PCI fixup, initcalls etc which are only half the size on 64 bit
1333 architectures, and don't require runtime relocation on relocatable
1334 kernels.
1335
ce9084ba
AB
1336config ARCH_USE_MEMREMAP_PROT
1337 bool
1338
fb346fd9
WL
1339config LOCK_EVENT_COUNTS
1340 bool "Locking event counts collection"
1341 depends on DEBUG_FS
a7f7f624 1342 help
fb346fd9
WL
1343 Enable light-weight counting of various locking related events
1344 in the system with minimal performance impact. This reduces
1345 the chance of application behavior change because of timing
1346 differences. The counts are reported via debugfs.
1347
5cf896fb
PC
1348# Select if the architecture has support for applying RELR relocations.
1349config ARCH_HAS_RELR
1350 bool
1351
1352config RELR
1353 bool "Use RELR relocation packing"
1354 depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR
1355 default y
1356 help
1357 Store the kernel's dynamic relocations in the RELR relocation packing
1358 format. Requires a compatible linker (LLD supports this feature), as
1359 well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy
1360 are compatible).
1361
0c9c1d56
TJB
1362config ARCH_HAS_MEM_ENCRYPT
1363 bool
1364
46b49b12
TL
1365config ARCH_HAS_CC_PLATFORM
1366 bool
1367
0e242208 1368config HAVE_SPARSE_SYSCALL_NR
9f79ffc1
JH
1369 bool
1370 help
1371 An architecture should select this if its syscall numbering is sparse
0e242208
HN
1372 to save space. For example, MIPS architecture has a syscall array with
1373 entries at 4000, 5000 and 6000 locations. This option turns on syscall
1374 related optimizations for a given architecture.
1375
d60d7de3
SS
1376config ARCH_HAS_VDSO_DATA
1377 bool
1378
115284d8
JP
1379config HAVE_STATIC_CALL
1380 bool
1381
9183c3f9
JP
1382config HAVE_STATIC_CALL_INLINE
1383 bool
1384 depends on HAVE_STATIC_CALL
03f16cd0 1385 select OBJTOOL
9183c3f9 1386
6ef869e0
MH
1387config HAVE_PREEMPT_DYNAMIC
1388 bool
99cf983c
MR
1389
1390config HAVE_PREEMPT_DYNAMIC_CALL
1391 bool
6ef869e0 1392 depends on HAVE_STATIC_CALL
99cf983c
MR
1393 select HAVE_PREEMPT_DYNAMIC
1394 help
9f79ffc1
JH
1395 An architecture should select this if it can handle the preemption
1396 model being selected at boot time using static calls.
99cf983c 1397
9f79ffc1
JH
1398 Where an architecture selects HAVE_STATIC_CALL_INLINE, any call to a
1399 preemption function will be patched directly.
99cf983c 1400
9f79ffc1
JH
1401 Where an architecture does not select HAVE_STATIC_CALL_INLINE, any
1402 call to a preemption function will go through a trampoline, and the
1403 trampoline will be patched.
99cf983c 1404
9f79ffc1
JH
1405 It is strongly advised to support inline static call to avoid any
1406 overhead.
99cf983c
MR
1407
1408config HAVE_PREEMPT_DYNAMIC_KEY
1409 bool
a0a12c3e 1410 depends on HAVE_ARCH_JUMP_LABEL
99cf983c 1411 select HAVE_PREEMPT_DYNAMIC
6ef869e0 1412 help
9f79ffc1
JH
1413 An architecture should select this if it can handle the preemption
1414 model being selected at boot time using static keys.
99cf983c 1415
9f79ffc1
JH
1416 Each preemption function will be given an early return based on a
1417 static key. This should have slightly lower overhead than non-inline
1418 static calls, as this effectively inlines each trampoline into the
1419 start of its callee. This may avoid redundant work, and may
1420 integrate better with CFI schemes.
99cf983c 1421
9f79ffc1
JH
1422 This will have greater overhead than using inline static calls as
1423 the call to the preemption function cannot be entirely elided.
6ef869e0 1424
59612b24
NC
1425config ARCH_WANT_LD_ORPHAN_WARN
1426 bool
1427 help
1428 An arch should select this symbol once all linker sections are explicitly
1429 included, size-asserted, or discarded in the linker scripts. This is
1430 important because we never want expected sections to be placed heuristically
1431 by the linker, since the locations of such sections can change between linker
1432 versions.
1433
4f5b0c17
MR
1434config HAVE_ARCH_PFN_VALID
1435 bool
1436
5d6ad668
MR
1437config ARCH_SUPPORTS_DEBUG_PAGEALLOC
1438 bool
1439
df4e817b
PT
1440config ARCH_SUPPORTS_PAGE_TABLE_CHECK
1441 bool
1442
2ca408d9
BG
1443config ARCH_SPLIT_ARG64
1444 bool
1445 help
9f79ffc1
JH
1446 If a 32-bit architecture requires 64-bit arguments to be split into
1447 pairs of 32-bit arguments, select this option.
2ca408d9 1448
7facdc42
AV
1449config ARCH_HAS_ELFCORE_COMPAT
1450 bool
1451
58e106e7
BS
1452config ARCH_HAS_PARANOID_L1D_FLUSH
1453 bool
1454
d593d64f
PS
1455config ARCH_HAVE_TRACE_MMIO_ACCESS
1456 bool
1457
1bdda24c
TG
1458config DYNAMIC_SIGFRAME
1459 bool
1460
50468e43
JS
1461# Select, if arch has a named attribute group bound to NUMA device nodes.
1462config HAVE_ARCH_NODE_DEV_GROUP
1463 bool
1464
71ce1ab5
KH
1465config ARCH_HAS_HW_PTE_YOUNG
1466 bool
1467 help
1468 Architectures that select this option are capable of setting the
1469 accessed bit in PTE entries when using them as part of linear address
1470 translations. Architectures that require runtime check should select
1471 this option and override arch_has_hw_pte_young().
1472
eed9a328
YZ
1473config ARCH_HAS_NONLEAF_PMD_YOUNG
1474 bool
1475 help
1476 Architectures that select this option are capable of setting the
1477 accessed bit in non-leaf PMD entries when using them as part of linear
1478 address translations. Page table walkers that clear the accessed bit
1479 may use this capability to reduce their search space.
1480
2521f2c2 1481source "kernel/gcov/Kconfig"
45332b1b
MY
1482
1483source "scripts/gcc-plugins/Kconfig"
fa1b5d09 1484
d49a0626
PZ
1485config FUNCTION_ALIGNMENT_4B
1486 bool
1487
1488config FUNCTION_ALIGNMENT_8B
1489 bool
1490
1491config FUNCTION_ALIGNMENT_16B
1492 bool
1493
1494config FUNCTION_ALIGNMENT_32B
1495 bool
1496
1497config FUNCTION_ALIGNMENT_64B
1498 bool
1499
1500config FUNCTION_ALIGNMENT
1501 int
1502 default 64 if FUNCTION_ALIGNMENT_64B
1503 default 32 if FUNCTION_ALIGNMENT_32B
1504 default 16 if FUNCTION_ALIGNMENT_16B
1505 default 8 if FUNCTION_ALIGNMENT_8B
1506 default 4 if FUNCTION_ALIGNMENT_4B
1507 default 0
1508
22471e13 1509endmenu
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