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