1# SPDX-License-Identifier: GPL-2.0-only
2config CC_VERSION_TEXT
3	string
4	default "$(CC_VERSION_TEXT)"
5	help
6	  This is used in unclear ways:
7
8	  - Re-run Kconfig when the compiler is updated
9	    The 'default' property references the environment variable,
10	    CC_VERSION_TEXT so it is recorded in include/config/auto.conf.cmd.
11	    When the compiler is updated, Kconfig will be invoked.
12
13	  - Ensure full rebuild when the compiler is updated
14	    include/linux/compiler-version.h contains this option in the comment
15	    line so fixdep adds include/config/CC_VERSION_TEXT into the
16	    auto-generated dependency. When the compiler is updated, syncconfig
17	    will touch it and then every file will be rebuilt.
18
19config CC_IS_GCC
20	def_bool $(success,test "$(cc-name)" = GCC)
21
22config GCC_VERSION
23	int
24	default $(cc-version) if CC_IS_GCC
25	default 0
26
27config CC_IS_CLANG
28	def_bool $(success,test "$(cc-name)" = Clang)
29
30config CLANG_VERSION
31	int
32	default $(cc-version) if CC_IS_CLANG
33	default 0
34
35config AS_IS_GNU
36	def_bool $(success,test "$(as-name)" = GNU)
37
38config AS_IS_LLVM
39	def_bool $(success,test "$(as-name)" = LLVM)
40
41config AS_VERSION
42	int
43	# Use clang version if this is the integrated assembler
44	default CLANG_VERSION if AS_IS_LLVM
45	default $(as-version)
46
47config LD_IS_BFD
48	def_bool $(success,test "$(ld-name)" = BFD)
49
50config LD_VERSION
51	int
52	default $(ld-version) if LD_IS_BFD
53	default 0
54
55config LD_IS_LLD
56	def_bool $(success,test "$(ld-name)" = LLD)
57
58config LLD_VERSION
59	int
60	default $(ld-version) if LD_IS_LLD
61	default 0
62
63config RUST_IS_AVAILABLE
64	def_bool $(success,$(srctree)/scripts/rust_is_available.sh)
65	help
66	  This shows whether a suitable Rust toolchain is available (found).
67
68	  Please see Documentation/rust/quick-start.rst for instructions on how
69	  to satisfy the build requirements of Rust support.
70
71	  In particular, the Makefile target 'rustavailable' is useful to check
72	  why the Rust toolchain is not being detected.
73
74config CC_CAN_LINK
75	bool
76	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag)) if 64BIT
77	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m32-flag))
78
79config CC_CAN_LINK_STATIC
80	bool
81	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag) -static) if 64BIT
82	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m32-flag) -static)
83
84config CC_HAS_ASM_GOTO_OUTPUT
85	def_bool $(success,echo 'int foo(int x) { asm goto ("": "=r"(x) ::: bar); return x; bar: return 0; }' | $(CC) -x c - -c -o /dev/null)
86
87config CC_HAS_ASM_GOTO_TIED_OUTPUT
88	depends on CC_HAS_ASM_GOTO_OUTPUT
89	# Detect buggy gcc and clang, fixed in gcc-11 clang-14.
90	def_bool $(success,echo 'int foo(int *x) { asm goto (".long (%l[bar]) - .": "+m"(*x) ::: bar); return *x; bar: return 0; }' | $CC -x c - -c -o /dev/null)
91
92config TOOLS_SUPPORT_RELR
93	def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh)
94
95config CC_HAS_ASM_INLINE
96	def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null)
97
98config CC_HAS_NO_PROFILE_FN_ATTR
99	def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror)
100
101config PAHOLE_VERSION
102	int
103	default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE))
104
105config CONSTRUCTORS
106	bool
107
108config IRQ_WORK
109	bool
110
111config BUILDTIME_TABLE_SORT
112	bool
113
114config THREAD_INFO_IN_TASK
115	bool
116	help
117	  Select this to move thread_info off the stack into task_struct.  To
118	  make this work, an arch will need to remove all thread_info fields
119	  except flags and fix any runtime bugs.
120
121	  One subtle change that will be needed is to use try_get_task_stack()
122	  and put_task_stack() in save_thread_stack_tsk() and get_wchan().
123
124menu "General setup"
125
126config BROKEN
127	bool
128
129config BROKEN_ON_SMP
130	bool
131	depends on BROKEN || !SMP
132	default y
133
134config INIT_ENV_ARG_LIMIT
135	int
136	default 32 if !UML
137	default 128 if UML
138	help
139	  Maximum of each of the number of arguments and environment
140	  variables passed to init from the kernel command line.
141
142config COMPILE_TEST
143	bool "Compile also drivers which will not load"
144	depends on HAS_IOMEM
145	help
146	  Some drivers can be compiled on a different platform than they are
147	  intended to be run on. Despite they cannot be loaded there (or even
148	  when they load they cannot be used due to missing HW support),
149	  developers still, opposing to distributors, might want to build such
150	  drivers to compile-test them.
151
152	  If you are a developer and want to build everything available, say Y
153	  here. If you are a user/distributor, say N here to exclude useless
154	  drivers to be distributed.
155
156config WERROR
157	bool "Compile the kernel with warnings as errors"
158	default COMPILE_TEST
159	help
160	  A kernel build should not cause any compiler warnings, and this
161	  enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags
162	  to enforce that rule by default. Certain warnings from other tools
163	  such as the linker may be upgraded to errors with this option as
164	  well.
165
166	  However, if you have a new (or very old) compiler or linker with odd
167	  and unusual warnings, or you have some architecture with problems,
168	  you may need to disable this config option in order to
169	  successfully build the kernel.
170
171	  If in doubt, say Y.
172
173config UAPI_HEADER_TEST
174	bool "Compile test UAPI headers"
175	depends on HEADERS_INSTALL && CC_CAN_LINK
176	help
177	  Compile test headers exported to user-space to ensure they are
178	  self-contained, i.e. compilable as standalone units.
179
180	  If you are a developer or tester and want to ensure the exported
181	  headers are self-contained, say Y here. Otherwise, choose N.
182
183config LOCALVERSION
184	string "Local version - append to kernel release"
185	help
186	  Append an extra string to the end of your kernel version.
187	  This will show up when you type uname, for example.
188	  The string you set here will be appended after the contents of
189	  any files with a filename matching localversion* in your
190	  object and source tree, in that order.  Your total string can
191	  be a maximum of 64 characters.
192
193config LOCALVERSION_AUTO
194	bool "Automatically append version information to the version string"
195	default y
196	depends on !COMPILE_TEST
197	help
198	  This will try to automatically determine if the current tree is a
199	  release tree by looking for git tags that belong to the current
200	  top of tree revision.
201
202	  A string of the format -gxxxxxxxx will be added to the localversion
203	  if a git-based tree is found.  The string generated by this will be
204	  appended after any matching localversion* files, and after the value
205	  set in CONFIG_LOCALVERSION.
206
207	  (The actual string used here is the first 12 characters produced
208	  by running the command:
209
210	    $ git rev-parse --verify HEAD
211
212	  which is done within the script "scripts/setlocalversion".)
213
214config BUILD_SALT
215	string "Build ID Salt"
216	default ""
217	help
218	  The build ID is used to link binaries and their debug info. Setting
219	  this option will use the value in the calculation of the build id.
220	  This is mostly useful for distributions which want to ensure the
221	  build is unique between builds. It's safe to leave the default.
222
223config HAVE_KERNEL_GZIP
224	bool
225
226config HAVE_KERNEL_BZIP2
227	bool
228
229config HAVE_KERNEL_LZMA
230	bool
231
232config HAVE_KERNEL_XZ
233	bool
234
235config HAVE_KERNEL_LZO
236	bool
237
238config HAVE_KERNEL_LZ4
239	bool
240
241config HAVE_KERNEL_ZSTD
242	bool
243
244config HAVE_KERNEL_UNCOMPRESSED
245	bool
246
247choice
248	prompt "Kernel compression mode"
249	default KERNEL_GZIP
250	depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 || HAVE_KERNEL_ZSTD || HAVE_KERNEL_UNCOMPRESSED
251	help
252	  The linux kernel is a kind of self-extracting executable.
253	  Several compression algorithms are available, which differ
254	  in efficiency, compression and decompression speed.
255	  Compression speed is only relevant when building a kernel.
256	  Decompression speed is relevant at each boot.
257
258	  If you have any problems with bzip2 or lzma compressed
259	  kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
260	  version of this functionality (bzip2 only), for 2.4, was
261	  supplied by Christian Ludwig)
262
263	  High compression options are mostly useful for users, who
264	  are low on disk space (embedded systems), but for whom ram
265	  size matters less.
266
267	  If in doubt, select 'gzip'
268
269config KERNEL_GZIP
270	bool "Gzip"
271	depends on HAVE_KERNEL_GZIP
272	help
273	  The old and tried gzip compression. It provides a good balance
274	  between compression ratio and decompression speed.
275
276config KERNEL_BZIP2
277	bool "Bzip2"
278	depends on HAVE_KERNEL_BZIP2
279	help
280	  Its compression ratio and speed is intermediate.
281	  Decompression speed is slowest among the choices.  The kernel
282	  size is about 10% smaller with bzip2, in comparison to gzip.
283	  Bzip2 uses a large amount of memory. For modern kernels you
284	  will need at least 8MB RAM or more for booting.
285
286config KERNEL_LZMA
287	bool "LZMA"
288	depends on HAVE_KERNEL_LZMA
289	help
290	  This compression algorithm's ratio is best.  Decompression speed
291	  is between gzip and bzip2.  Compression is slowest.
292	  The kernel size is about 33% smaller with LZMA in comparison to gzip.
293
294config KERNEL_XZ
295	bool "XZ"
296	depends on HAVE_KERNEL_XZ
297	help
298	  XZ uses the LZMA2 algorithm and instruction set specific
299	  BCJ filters which can improve compression ratio of executable
300	  code. The size of the kernel is about 30% smaller with XZ in
301	  comparison to gzip. On architectures for which there is a BCJ
302	  filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
303	  will create a few percent smaller kernel than plain LZMA.
304
305	  The speed is about the same as with LZMA: The decompression
306	  speed of XZ is better than that of bzip2 but worse than gzip
307	  and LZO. Compression is slow.
308
309config KERNEL_LZO
310	bool "LZO"
311	depends on HAVE_KERNEL_LZO
312	help
313	  Its compression ratio is the poorest among the choices. The kernel
314	  size is about 10% bigger than gzip; however its speed
315	  (both compression and decompression) is the fastest.
316
317config KERNEL_LZ4
318	bool "LZ4"
319	depends on HAVE_KERNEL_LZ4
320	help
321	  LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
322	  A preliminary version of LZ4 de/compression tool is available at
323	  <https://code.google.com/p/lz4/>.
324
325	  Its compression ratio is worse than LZO. The size of the kernel
326	  is about 8% bigger than LZO. But the decompression speed is
327	  faster than LZO.
328
329config KERNEL_ZSTD
330	bool "ZSTD"
331	depends on HAVE_KERNEL_ZSTD
332	help
333	  ZSTD is a compression algorithm targeting intermediate compression
334	  with fast decompression speed. It will compress better than GZIP and
335	  decompress around the same speed as LZO, but slower than LZ4. You
336	  will need at least 192 KB RAM or more for booting. The zstd command
337	  line tool is required for compression.
338
339config KERNEL_UNCOMPRESSED
340	bool "None"
341	depends on HAVE_KERNEL_UNCOMPRESSED
342	help
343	  Produce uncompressed kernel image. This option is usually not what
344	  you want. It is useful for debugging the kernel in slow simulation
345	  environments, where decompressing and moving the kernel is awfully
346	  slow. This option allows early boot code to skip the decompressor
347	  and jump right at uncompressed kernel image.
348
349endchoice
350
351config DEFAULT_INIT
352	string "Default init path"
353	default ""
354	help
355	  This option determines the default init for the system if no init=
356	  option is passed on the kernel command line. If the requested path is
357	  not present, we will still then move on to attempting further
358	  locations (e.g. /sbin/init, etc). If this is empty, we will just use
359	  the fallback list when init= is not passed.
360
361config DEFAULT_HOSTNAME
362	string "Default hostname"
363	default "(none)"
364	help
365	  This option determines the default system hostname before userspace
366	  calls sethostname(2). The kernel traditionally uses "(none)" here,
367	  but you may wish to use a different default here to make a minimal
368	  system more usable with less configuration.
369
370config SYSVIPC
371	bool "System V IPC"
372	help
373	  Inter Process Communication is a suite of library functions and
374	  system calls which let processes (running programs) synchronize and
375	  exchange information. It is generally considered to be a good thing,
376	  and some programs won't run unless you say Y here. In particular, if
377	  you want to run the DOS emulator dosemu under Linux (read the
378	  DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
379	  you'll need to say Y here.
380
381	  You can find documentation about IPC with "info ipc" and also in
382	  section 6.4 of the Linux Programmer's Guide, available from
383	  <http://www.tldp.org/guides.html>.
384
385config SYSVIPC_SYSCTL
386	bool
387	depends on SYSVIPC
388	depends on SYSCTL
389	default y
390
391config SYSVIPC_COMPAT
392	def_bool y
393	depends on COMPAT && SYSVIPC
394
395config POSIX_MQUEUE
396	bool "POSIX Message Queues"
397	depends on NET
398	help
399	  POSIX variant of message queues is a part of IPC. In POSIX message
400	  queues every message has a priority which decides about succession
401	  of receiving it by a process. If you want to compile and run
402	  programs written e.g. for Solaris with use of its POSIX message
403	  queues (functions mq_*) say Y here.
404
405	  POSIX message queues are visible as a filesystem called 'mqueue'
406	  and can be mounted somewhere if you want to do filesystem
407	  operations on message queues.
408
409	  If unsure, say Y.
410
411config POSIX_MQUEUE_SYSCTL
412	bool
413	depends on POSIX_MQUEUE
414	depends on SYSCTL
415	default y
416
417config WATCH_QUEUE
418	bool "General notification queue"
419	default n
420	help
421
422	  This is a general notification queue for the kernel to pass events to
423	  userspace by splicing them into pipes.  It can be used in conjunction
424	  with watches for key/keyring change notifications and device
425	  notifications.
426
427	  See Documentation/core-api/watch_queue.rst
428
429config CROSS_MEMORY_ATTACH
430	bool "Enable process_vm_readv/writev syscalls"
431	depends on MMU
432	default y
433	help
434	  Enabling this option adds the system calls process_vm_readv and
435	  process_vm_writev which allow a process with the correct privileges
436	  to directly read from or write to another process' address space.
437	  See the man page for more details.
438
439config USELIB
440	bool "uselib syscall (for libc5 and earlier)"
441	default ALPHA || M68K || SPARC
442	help
443	  This option enables the uselib syscall, a system call used in the
444	  dynamic linker from libc5 and earlier.  glibc does not use this
445	  system call.  If you intend to run programs built on libc5 or
446	  earlier, you may need to enable this syscall.  Current systems
447	  running glibc can safely disable this.
448
449config AUDIT
450	bool "Auditing support"
451	depends on NET
452	help
453	  Enable auditing infrastructure that can be used with another
454	  kernel subsystem, such as SELinux (which requires this for
455	  logging of avc messages output).  System call auditing is included
456	  on architectures which support it.
457
458config HAVE_ARCH_AUDITSYSCALL
459	bool
460
461config AUDITSYSCALL
462	def_bool y
463	depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
464	select FSNOTIFY
465
466source "kernel/irq/Kconfig"
467source "kernel/time/Kconfig"
468source "kernel/bpf/Kconfig"
469source "kernel/Kconfig.preempt"
470
471menu "CPU/Task time and stats accounting"
472
473config VIRT_CPU_ACCOUNTING
474	bool
475
476choice
477	prompt "Cputime accounting"
478	default TICK_CPU_ACCOUNTING
479
480# Kind of a stub config for the pure tick based cputime accounting
481config TICK_CPU_ACCOUNTING
482	bool "Simple tick based cputime accounting"
483	depends on !S390 && !NO_HZ_FULL
484	help
485	  This is the basic tick based cputime accounting that maintains
486	  statistics about user, system and idle time spent on per jiffies
487	  granularity.
488
489	  If unsure, say Y.
490
491config VIRT_CPU_ACCOUNTING_NATIVE
492	bool "Deterministic task and CPU time accounting"
493	depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
494	select VIRT_CPU_ACCOUNTING
495	help
496	  Select this option to enable more accurate task and CPU time
497	  accounting.  This is done by reading a CPU counter on each
498	  kernel entry and exit and on transitions within the kernel
499	  between system, softirq and hardirq state, so there is a
500	  small performance impact.  In the case of s390 or IBM POWER > 5,
501	  this also enables accounting of stolen time on logically-partitioned
502	  systems.
503
504config VIRT_CPU_ACCOUNTING_GEN
505	bool "Full dynticks CPU time accounting"
506	depends on HAVE_CONTEXT_TRACKING_USER
507	depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
508	depends on GENERIC_CLOCKEVENTS
509	select VIRT_CPU_ACCOUNTING
510	select CONTEXT_TRACKING_USER
511	help
512	  Select this option to enable task and CPU time accounting on full
513	  dynticks systems. This accounting is implemented by watching every
514	  kernel-user boundaries using the context tracking subsystem.
515	  The accounting is thus performed at the expense of some significant
516	  overhead.
517
518	  For now this is only useful if you are working on the full
519	  dynticks subsystem development.
520
521	  If unsure, say N.
522
523endchoice
524
525config IRQ_TIME_ACCOUNTING
526	bool "Fine granularity task level IRQ time accounting"
527	depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
528	help
529	  Select this option to enable fine granularity task irq time
530	  accounting. This is done by reading a timestamp on each
531	  transitions between softirq and hardirq state, so there can be a
532	  small performance impact.
533
534	  If in doubt, say N here.
535
536config HAVE_SCHED_AVG_IRQ
537	def_bool y
538	depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING
539	depends on SMP
540
541config SCHED_THERMAL_PRESSURE
542	bool
543	default y if ARM && ARM_CPU_TOPOLOGY
544	default y if ARM64
545	depends on SMP
546	depends on CPU_FREQ_THERMAL
547	help
548	  Select this option to enable thermal pressure accounting in the
549	  scheduler. Thermal pressure is the value conveyed to the scheduler
550	  that reflects the reduction in CPU compute capacity resulted from
551	  thermal throttling. Thermal throttling occurs when the performance of
552	  a CPU is capped due to high operating temperatures.
553
554	  If selected, the scheduler will be able to balance tasks accordingly,
555	  i.e. put less load on throttled CPUs than on non/less throttled ones.
556
557	  This requires the architecture to implement
558	  arch_update_thermal_pressure() and arch_scale_thermal_pressure().
559
560config BSD_PROCESS_ACCT
561	bool "BSD Process Accounting"
562	depends on MULTIUSER
563	help
564	  If you say Y here, a user level program will be able to instruct the
565	  kernel (via a special system call) to write process accounting
566	  information to a file: whenever a process exits, information about
567	  that process will be appended to the file by the kernel.  The
568	  information includes things such as creation time, owning user,
569	  command name, memory usage, controlling terminal etc. (the complete
570	  list is in the struct acct in <file:include/linux/acct.h>).  It is
571	  up to the user level program to do useful things with this
572	  information.  This is generally a good idea, so say Y.
573
574config BSD_PROCESS_ACCT_V3
575	bool "BSD Process Accounting version 3 file format"
576	depends on BSD_PROCESS_ACCT
577	default n
578	help
579	  If you say Y here, the process accounting information is written
580	  in a new file format that also logs the process IDs of each
581	  process and its parent. Note that this file format is incompatible
582	  with previous v0/v1/v2 file formats, so you will need updated tools
583	  for processing it. A preliminary version of these tools is available
584	  at <http://www.gnu.org/software/acct/>.
585
586config TASKSTATS
587	bool "Export task/process statistics through netlink"
588	depends on NET
589	depends on MULTIUSER
590	default n
591	help
592	  Export selected statistics for tasks/processes through the
593	  generic netlink interface. Unlike BSD process accounting, the
594	  statistics are available during the lifetime of tasks/processes as
595	  responses to commands. Like BSD accounting, they are sent to user
596	  space on task exit.
597
598	  Say N if unsure.
599
600config TASK_DELAY_ACCT
601	bool "Enable per-task delay accounting"
602	depends on TASKSTATS
603	select SCHED_INFO
604	help
605	  Collect information on time spent by a task waiting for system
606	  resources like cpu, synchronous block I/O completion and swapping
607	  in pages. Such statistics can help in setting a task's priorities
608	  relative to other tasks for cpu, io, rss limits etc.
609
610	  Say N if unsure.
611
612config TASK_XACCT
613	bool "Enable extended accounting over taskstats"
614	depends on TASKSTATS
615	help
616	  Collect extended task accounting data and send the data
617	  to userland for processing over the taskstats interface.
618
619	  Say N if unsure.
620
621config TASK_IO_ACCOUNTING
622	bool "Enable per-task storage I/O accounting"
623	depends on TASK_XACCT
624	help
625	  Collect information on the number of bytes of storage I/O which this
626	  task has caused.
627
628	  Say N if unsure.
629
630config PSI
631	bool "Pressure stall information tracking"
632	help
633	  Collect metrics that indicate how overcommitted the CPU, memory,
634	  and IO capacity are in the system.
635
636	  If you say Y here, the kernel will create /proc/pressure/ with the
637	  pressure statistics files cpu, memory, and io. These will indicate
638	  the share of walltime in which some or all tasks in the system are
639	  delayed due to contention of the respective resource.
640
641	  In kernels with cgroup support, cgroups (cgroup2 only) will
642	  have cpu.pressure, memory.pressure, and io.pressure files,
643	  which aggregate pressure stalls for the grouped tasks only.
644
645	  For more details see Documentation/accounting/psi.rst.
646
647	  Say N if unsure.
648
649config PSI_DEFAULT_DISABLED
650	bool "Require boot parameter to enable pressure stall information tracking"
651	default n
652	depends on PSI
653	help
654	  If set, pressure stall information tracking will be disabled
655	  per default but can be enabled through passing psi=1 on the
656	  kernel commandline during boot.
657
658	  This feature adds some code to the task wakeup and sleep
659	  paths of the scheduler. The overhead is too low to affect
660	  common scheduling-intense workloads in practice (such as
661	  webservers, memcache), but it does show up in artificial
662	  scheduler stress tests, such as hackbench.
663
664	  If you are paranoid and not sure what the kernel will be
665	  used for, say Y.
666
667	  Say N if unsure.
668
669endmenu # "CPU/Task time and stats accounting"
670
671config CPU_ISOLATION
672	bool "CPU isolation"
673	depends on SMP || COMPILE_TEST
674	default y
675	help
676	  Make sure that CPUs running critical tasks are not disturbed by
677	  any source of "noise" such as unbound workqueues, timers, kthreads...
678	  Unbound jobs get offloaded to housekeeping CPUs. This is driven by
679	  the "isolcpus=" boot parameter.
680
681	  Say Y if unsure.
682
683source "kernel/rcu/Kconfig"
684
685config IKCONFIG
686	tristate "Kernel .config support"
687	help
688	  This option enables the complete Linux kernel ".config" file
689	  contents to be saved in the kernel. It provides documentation
690	  of which kernel options are used in a running kernel or in an
691	  on-disk kernel.  This information can be extracted from the kernel
692	  image file with the script scripts/extract-ikconfig and used as
693	  input to rebuild the current kernel or to build another kernel.
694	  It can also be extracted from a running kernel by reading
695	  /proc/config.gz if enabled (below).
696
697config IKCONFIG_PROC
698	bool "Enable access to .config through /proc/config.gz"
699	depends on IKCONFIG && PROC_FS
700	help
701	  This option enables access to the kernel configuration file
702	  through /proc/config.gz.
703
704config IKHEADERS
705	tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz"
706	depends on SYSFS
707	help
708	  This option enables access to the in-kernel headers that are generated during
709	  the build process. These can be used to build eBPF tracing programs,
710	  or similar programs.  If you build the headers as a module, a module called
711	  kheaders.ko is built which can be loaded on-demand to get access to headers.
712
713config LOG_BUF_SHIFT
714	int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
715	range 12 25
716	default 17
717	depends on PRINTK
718	help
719	  Select the minimal kernel log buffer size as a power of 2.
720	  The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
721	  parameter, see below. Any higher size also might be forced
722	  by "log_buf_len" boot parameter.
723
724	  Examples:
725		     17 => 128 KB
726		     16 => 64 KB
727		     15 => 32 KB
728		     14 => 16 KB
729		     13 =>  8 KB
730		     12 =>  4 KB
731
732config LOG_CPU_MAX_BUF_SHIFT
733	int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
734	depends on SMP
735	range 0 21
736	default 12 if !BASE_SMALL
737	default 0 if BASE_SMALL
738	depends on PRINTK
739	help
740	  This option allows to increase the default ring buffer size
741	  according to the number of CPUs. The value defines the contribution
742	  of each CPU as a power of 2. The used space is typically only few
743	  lines however it might be much more when problems are reported,
744	  e.g. backtraces.
745
746	  The increased size means that a new buffer has to be allocated and
747	  the original static one is unused. It makes sense only on systems
748	  with more CPUs. Therefore this value is used only when the sum of
749	  contributions is greater than the half of the default kernel ring
750	  buffer as defined by LOG_BUF_SHIFT. The default values are set
751	  so that more than 16 CPUs are needed to trigger the allocation.
752
753	  Also this option is ignored when "log_buf_len" kernel parameter is
754	  used as it forces an exact (power of two) size of the ring buffer.
755
756	  The number of possible CPUs is used for this computation ignoring
757	  hotplugging making the computation optimal for the worst case
758	  scenario while allowing a simple algorithm to be used from bootup.
759
760	  Examples shift values and their meaning:
761		     17 => 128 KB for each CPU
762		     16 =>  64 KB for each CPU
763		     15 =>  32 KB for each CPU
764		     14 =>  16 KB for each CPU
765		     13 =>   8 KB for each CPU
766		     12 =>   4 KB for each CPU
767
768config PRINTK_SAFE_LOG_BUF_SHIFT
769	int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)"
770	range 10 21
771	default 13
772	depends on PRINTK
773	help
774	  Select the size of an alternate printk per-CPU buffer where messages
775	  printed from unsafe contexts are temporary stored. One example would
776	  be NMI messages, another one - printk recursion. The messages are
777	  copied to the main log buffer in a safe context to avoid a deadlock.
778	  The value defines the size as a power of 2.
779
780	  Those messages are rare and limited. The largest one is when
781	  a backtrace is printed. It usually fits into 4KB. Select
782	  8KB if you want to be on the safe side.
783
784	  Examples:
785		     17 => 128 KB for each CPU
786		     16 =>  64 KB for each CPU
787		     15 =>  32 KB for each CPU
788		     14 =>  16 KB for each CPU
789		     13 =>   8 KB for each CPU
790		     12 =>   4 KB for each CPU
791
792config PRINTK_INDEX
793	bool "Printk indexing debugfs interface"
794	depends on PRINTK && DEBUG_FS
795	help
796	  Add support for indexing of all printk formats known at compile time
797	  at <debugfs>/printk/index/<module>.
798
799	  This can be used as part of maintaining daemons which monitor
800	  /dev/kmsg, as it permits auditing the printk formats present in a
801	  kernel, allowing detection of cases where monitored printks are
802	  changed or no longer present.
803
804	  There is no additional runtime cost to printk with this enabled.
805
806#
807# Architectures with an unreliable sched_clock() should select this:
808#
809config HAVE_UNSTABLE_SCHED_CLOCK
810	bool
811
812config GENERIC_SCHED_CLOCK
813	bool
814
815menu "Scheduler features"
816
817config UCLAMP_TASK
818	bool "Enable utilization clamping for RT/FAIR tasks"
819	depends on CPU_FREQ_GOV_SCHEDUTIL
820	help
821	  This feature enables the scheduler to track the clamped utilization
822	  of each CPU based on RUNNABLE tasks scheduled on that CPU.
823
824	  With this option, the user can specify the min and max CPU
825	  utilization allowed for RUNNABLE tasks. The max utilization defines
826	  the maximum frequency a task should use while the min utilization
827	  defines the minimum frequency it should use.
828
829	  Both min and max utilization clamp values are hints to the scheduler,
830	  aiming at improving its frequency selection policy, but they do not
831	  enforce or grant any specific bandwidth for tasks.
832
833	  If in doubt, say N.
834
835config UCLAMP_BUCKETS_COUNT
836	int "Number of supported utilization clamp buckets"
837	range 5 20
838	default 5
839	depends on UCLAMP_TASK
840	help
841	  Defines the number of clamp buckets to use. The range of each bucket
842	  will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the
843	  number of clamp buckets the finer their granularity and the higher
844	  the precision of clamping aggregation and tracking at run-time.
845
846	  For example, with the minimum configuration value we will have 5
847	  clamp buckets tracking 20% utilization each. A 25% boosted tasks will
848	  be refcounted in the [20..39]% bucket and will set the bucket clamp
849	  effective value to 25%.
850	  If a second 30% boosted task should be co-scheduled on the same CPU,
851	  that task will be refcounted in the same bucket of the first task and
852	  it will boost the bucket clamp effective value to 30%.
853	  The clamp effective value of a bucket is reset to its nominal value
854	  (20% in the example above) when there are no more tasks refcounted in
855	  that bucket.
856
857	  An additional boost/capping margin can be added to some tasks. In the
858	  example above the 25% task will be boosted to 30% until it exits the
859	  CPU. If that should be considered not acceptable on certain systems,
860	  it's always possible to reduce the margin by increasing the number of
861	  clamp buckets to trade off used memory for run-time tracking
862	  precision.
863
864	  If in doubt, use the default value.
865
866endmenu
867
868#
869# For architectures that want to enable the support for NUMA-affine scheduler
870# balancing logic:
871#
872config ARCH_SUPPORTS_NUMA_BALANCING
873	bool
874
875#
876# For architectures that prefer to flush all TLBs after a number of pages
877# are unmapped instead of sending one IPI per page to flush. The architecture
878# must provide guarantees on what happens if a clean TLB cache entry is
879# written after the unmap. Details are in mm/rmap.c near the check for
880# should_defer_flush. The architecture should also consider if the full flush
881# and the refill costs are offset by the savings of sending fewer IPIs.
882config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
883	bool
884
885config CC_HAS_INT128
886	def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT
887
888config CC_IMPLICIT_FALLTHROUGH
889	string
890	default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5)
891	default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough)
892
893# Currently, disable gcc-11,12 array-bounds globally.
894# We may want to target only particular configurations some day.
895config GCC11_NO_ARRAY_BOUNDS
896	def_bool y
897
898config GCC12_NO_ARRAY_BOUNDS
899	def_bool y
900
901config CC_NO_ARRAY_BOUNDS
902	bool
903	default y if CC_IS_GCC && GCC_VERSION >= 110000 && GCC_VERSION < 120000 && GCC11_NO_ARRAY_BOUNDS
904	default y if CC_IS_GCC && GCC_VERSION >= 120000 && GCC_VERSION < 130000 && GCC12_NO_ARRAY_BOUNDS
905
906#
907# For architectures that know their GCC __int128 support is sound
908#
909config ARCH_SUPPORTS_INT128
910	bool
911
912# For architectures that (ab)use NUMA to represent different memory regions
913# all cpu-local but of different latencies, such as SuperH.
914#
915config ARCH_WANT_NUMA_VARIABLE_LOCALITY
916	bool
917
918config NUMA_BALANCING
919	bool "Memory placement aware NUMA scheduler"
920	depends on ARCH_SUPPORTS_NUMA_BALANCING
921	depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
922	depends on SMP && NUMA && MIGRATION && !PREEMPT_RT
923	help
924	  This option adds support for automatic NUMA aware memory/task placement.
925	  The mechanism is quite primitive and is based on migrating memory when
926	  it has references to the node the task is running on.
927
928	  This system will be inactive on UMA systems.
929
930config NUMA_BALANCING_DEFAULT_ENABLED
931	bool "Automatically enable NUMA aware memory/task placement"
932	default y
933	depends on NUMA_BALANCING
934	help
935	  If set, automatic NUMA balancing will be enabled if running on a NUMA
936	  machine.
937
938menuconfig CGROUPS
939	bool "Control Group support"
940	select KERNFS
941	help
942	  This option adds support for grouping sets of processes together, for
943	  use with process control subsystems such as Cpusets, CFS, memory
944	  controls or device isolation.
945	  See
946		- Documentation/scheduler/sched-design-CFS.rst	(CFS)
947		- Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation
948					  and resource control)
949
950	  Say N if unsure.
951
952if CGROUPS
953
954config PAGE_COUNTER
955	bool
956
957config CGROUP_FAVOR_DYNMODS
958        bool "Favor dynamic modification latency reduction by default"
959        help
960          This option enables the "favordynmods" mount option by default
961          which reduces the latencies of dynamic cgroup modifications such
962          as task migrations and controller on/offs at the cost of making
963          hot path operations such as forks and exits more expensive.
964
965          Say N if unsure.
966
967config MEMCG
968	bool "Memory controller"
969	select PAGE_COUNTER
970	select EVENTFD
971	help
972	  Provides control over the memory footprint of tasks in a cgroup.
973
974config MEMCG_KMEM
975	bool
976	depends on MEMCG && !SLOB
977	default y
978
979config BLK_CGROUP
980	bool "IO controller"
981	depends on BLOCK
982	default n
983	help
984	Generic block IO controller cgroup interface. This is the common
985	cgroup interface which should be used by various IO controlling
986	policies.
987
988	Currently, CFQ IO scheduler uses it to recognize task groups and
989	control disk bandwidth allocation (proportional time slice allocation)
990	to such task groups. It is also used by bio throttling logic in
991	block layer to implement upper limit in IO rates on a device.
992
993	This option only enables generic Block IO controller infrastructure.
994	One needs to also enable actual IO controlling logic/policy. For
995	enabling proportional weight division of disk bandwidth in CFQ, set
996	CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
997	CONFIG_BLK_DEV_THROTTLING=y.
998
999	See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information.
1000
1001config CGROUP_WRITEBACK
1002	bool
1003	depends on MEMCG && BLK_CGROUP
1004	default y
1005
1006menuconfig CGROUP_SCHED
1007	bool "CPU controller"
1008	default n
1009	help
1010	  This feature lets CPU scheduler recognize task groups and control CPU
1011	  bandwidth allocation to such task groups. It uses cgroups to group
1012	  tasks.
1013
1014if CGROUP_SCHED
1015config FAIR_GROUP_SCHED
1016	bool "Group scheduling for SCHED_OTHER"
1017	depends on CGROUP_SCHED
1018	default CGROUP_SCHED
1019
1020config CFS_BANDWIDTH
1021	bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1022	depends on FAIR_GROUP_SCHED
1023	default n
1024	help
1025	  This option allows users to define CPU bandwidth rates (limits) for
1026	  tasks running within the fair group scheduler.  Groups with no limit
1027	  set are considered to be unconstrained and will run with no
1028	  restriction.
1029	  See Documentation/scheduler/sched-bwc.rst for more information.
1030
1031config RT_GROUP_SCHED
1032	bool "Group scheduling for SCHED_RR/FIFO"
1033	depends on CGROUP_SCHED
1034	default n
1035	help
1036	  This feature lets you explicitly allocate real CPU bandwidth
1037	  to task groups. If enabled, it will also make it impossible to
1038	  schedule realtime tasks for non-root users until you allocate
1039	  realtime bandwidth for them.
1040	  See Documentation/scheduler/sched-rt-group.rst for more information.
1041
1042endif #CGROUP_SCHED
1043
1044config SCHED_MM_CID
1045	def_bool y
1046	depends on SMP && RSEQ
1047
1048config UCLAMP_TASK_GROUP
1049	bool "Utilization clamping per group of tasks"
1050	depends on CGROUP_SCHED
1051	depends on UCLAMP_TASK
1052	default n
1053	help
1054	  This feature enables the scheduler to track the clamped utilization
1055	  of each CPU based on RUNNABLE tasks currently scheduled on that CPU.
1056
1057	  When this option is enabled, the user can specify a min and max
1058	  CPU bandwidth which is allowed for each single task in a group.
1059	  The max bandwidth allows to clamp the maximum frequency a task
1060	  can use, while the min bandwidth allows to define a minimum
1061	  frequency a task will always use.
1062
1063	  When task group based utilization clamping is enabled, an eventually
1064	  specified task-specific clamp value is constrained by the cgroup
1065	  specified clamp value. Both minimum and maximum task clamping cannot
1066	  be bigger than the corresponding clamping defined at task group level.
1067
1068	  If in doubt, say N.
1069
1070config CGROUP_PIDS
1071	bool "PIDs controller"
1072	help
1073	  Provides enforcement of process number limits in the scope of a
1074	  cgroup. Any attempt to fork more processes than is allowed in the
1075	  cgroup will fail. PIDs are fundamentally a global resource because it
1076	  is fairly trivial to reach PID exhaustion before you reach even a
1077	  conservative kmemcg limit. As a result, it is possible to grind a
1078	  system to halt without being limited by other cgroup policies. The
1079	  PIDs controller is designed to stop this from happening.
1080
1081	  It should be noted that organisational operations (such as attaching
1082	  to a cgroup hierarchy) will *not* be blocked by the PIDs controller,
1083	  since the PIDs limit only affects a process's ability to fork, not to
1084	  attach to a cgroup.
1085
1086config CGROUP_RDMA
1087	bool "RDMA controller"
1088	help
1089	  Provides enforcement of RDMA resources defined by IB stack.
1090	  It is fairly easy for consumers to exhaust RDMA resources, which
1091	  can result into resource unavailability to other consumers.
1092	  RDMA controller is designed to stop this from happening.
1093	  Attaching processes with active RDMA resources to the cgroup
1094	  hierarchy is allowed even if can cross the hierarchy's limit.
1095
1096config CGROUP_FREEZER
1097	bool "Freezer controller"
1098	help
1099	  Provides a way to freeze and unfreeze all tasks in a
1100	  cgroup.
1101
1102	  This option affects the ORIGINAL cgroup interface. The cgroup2 memory
1103	  controller includes important in-kernel memory consumers per default.
1104
1105	  If you're using cgroup2, say N.
1106
1107config CGROUP_HUGETLB
1108	bool "HugeTLB controller"
1109	depends on HUGETLB_PAGE
1110	select PAGE_COUNTER
1111	default n
1112	help
1113	  Provides a cgroup controller for HugeTLB pages.
1114	  When you enable this, you can put a per cgroup limit on HugeTLB usage.
1115	  The limit is enforced during page fault. Since HugeTLB doesn't
1116	  support page reclaim, enforcing the limit at page fault time implies
1117	  that, the application will get SIGBUS signal if it tries to access
1118	  HugeTLB pages beyond its limit. This requires the application to know
1119	  beforehand how much HugeTLB pages it would require for its use. The
1120	  control group is tracked in the third page lru pointer. This means
1121	  that we cannot use the controller with huge page less than 3 pages.
1122
1123config CPUSETS
1124	bool "Cpuset controller"
1125	depends on SMP
1126	help
1127	  This option will let you create and manage CPUSETs which
1128	  allow dynamically partitioning a system into sets of CPUs and
1129	  Memory Nodes and assigning tasks to run only within those sets.
1130	  This is primarily useful on large SMP or NUMA systems.
1131
1132	  Say N if unsure.
1133
1134config PROC_PID_CPUSET
1135	bool "Include legacy /proc/<pid>/cpuset file"
1136	depends on CPUSETS
1137	default y
1138
1139config CGROUP_DEVICE
1140	bool "Device controller"
1141	help
1142	  Provides a cgroup controller implementing whitelists for
1143	  devices which a process in the cgroup can mknod or open.
1144
1145config CGROUP_CPUACCT
1146	bool "Simple CPU accounting controller"
1147	help
1148	  Provides a simple controller for monitoring the
1149	  total CPU consumed by the tasks in a cgroup.
1150
1151config CGROUP_PERF
1152	bool "Perf controller"
1153	depends on PERF_EVENTS
1154	help
1155	  This option extends the perf per-cpu mode to restrict monitoring
1156	  to threads which belong to the cgroup specified and run on the
1157	  designated cpu.  Or this can be used to have cgroup ID in samples
1158	  so that it can monitor performance events among cgroups.
1159
1160	  Say N if unsure.
1161
1162config CGROUP_BPF
1163	bool "Support for eBPF programs attached to cgroups"
1164	depends on BPF_SYSCALL
1165	select SOCK_CGROUP_DATA
1166	help
1167	  Allow attaching eBPF programs to a cgroup using the bpf(2)
1168	  syscall command BPF_PROG_ATTACH.
1169
1170	  In which context these programs are accessed depends on the type
1171	  of attachment. For instance, programs that are attached using
1172	  BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
1173	  inet sockets.
1174
1175config CGROUP_MISC
1176	bool "Misc resource controller"
1177	default n
1178	help
1179	  Provides a controller for miscellaneous resources on a host.
1180
1181	  Miscellaneous scalar resources are the resources on the host system
1182	  which cannot be abstracted like the other cgroups. This controller
1183	  tracks and limits the miscellaneous resources used by a process
1184	  attached to a cgroup hierarchy.
1185
1186	  For more information, please check misc cgroup section in
1187	  /Documentation/admin-guide/cgroup-v2.rst.
1188
1189config CGROUP_DEBUG
1190	bool "Debug controller"
1191	default n
1192	depends on DEBUG_KERNEL
1193	help
1194	  This option enables a simple controller that exports
1195	  debugging information about the cgroups framework. This
1196	  controller is for control cgroup debugging only. Its
1197	  interfaces are not stable.
1198
1199	  Say N.
1200
1201config SOCK_CGROUP_DATA
1202	bool
1203	default n
1204
1205endif # CGROUPS
1206
1207menuconfig NAMESPACES
1208	bool "Namespaces support" if EXPERT
1209	depends on MULTIUSER
1210	default !EXPERT
1211	help
1212	  Provides the way to make tasks work with different objects using
1213	  the same id. For example same IPC id may refer to different objects
1214	  or same user id or pid may refer to different tasks when used in
1215	  different namespaces.
1216
1217if NAMESPACES
1218
1219config UTS_NS
1220	bool "UTS namespace"
1221	default y
1222	help
1223	  In this namespace tasks see different info provided with the
1224	  uname() system call
1225
1226config TIME_NS
1227	bool "TIME namespace"
1228	depends on GENERIC_VDSO_TIME_NS
1229	default y
1230	help
1231	  In this namespace boottime and monotonic clocks can be set.
1232	  The time will keep going with the same pace.
1233
1234config IPC_NS
1235	bool "IPC namespace"
1236	depends on (SYSVIPC || POSIX_MQUEUE)
1237	default y
1238	help
1239	  In this namespace tasks work with IPC ids which correspond to
1240	  different IPC objects in different namespaces.
1241
1242config USER_NS
1243	bool "User namespace"
1244	default n
1245	help
1246	  This allows containers, i.e. vservers, to use user namespaces
1247	  to provide different user info for different servers.
1248
1249	  When user namespaces are enabled in the kernel it is
1250	  recommended that the MEMCG option also be enabled and that
1251	  user-space use the memory control groups to limit the amount
1252	  of memory a memory unprivileged users can use.
1253
1254	  If unsure, say N.
1255
1256config PID_NS
1257	bool "PID Namespaces"
1258	default y
1259	help
1260	  Support process id namespaces.  This allows having multiple
1261	  processes with the same pid as long as they are in different
1262	  pid namespaces.  This is a building block of containers.
1263
1264config NET_NS
1265	bool "Network namespace"
1266	depends on NET
1267	default y
1268	help
1269	  Allow user space to create what appear to be multiple instances
1270	  of the network stack.
1271
1272endif # NAMESPACES
1273
1274config CHECKPOINT_RESTORE
1275	bool "Checkpoint/restore support"
1276	depends on PROC_FS
1277	select PROC_CHILDREN
1278	select KCMP
1279	default n
1280	help
1281	  Enables additional kernel features in a sake of checkpoint/restore.
1282	  In particular it adds auxiliary prctl codes to setup process text,
1283	  data and heap segment sizes, and a few additional /proc filesystem
1284	  entries.
1285
1286	  If unsure, say N here.
1287
1288config SCHED_AUTOGROUP
1289	bool "Automatic process group scheduling"
1290	select CGROUPS
1291	select CGROUP_SCHED
1292	select FAIR_GROUP_SCHED
1293	help
1294	  This option optimizes the scheduler for common desktop workloads by
1295	  automatically creating and populating task groups.  This separation
1296	  of workloads isolates aggressive CPU burners (like build jobs) from
1297	  desktop applications.  Task group autogeneration is currently based
1298	  upon task session.
1299
1300config SYSFS_DEPRECATED
1301	bool "Enable deprecated sysfs features to support old userspace tools"
1302	depends on SYSFS
1303	default n
1304	help
1305	  This option adds code that switches the layout of the "block" class
1306	  devices, to not show up in /sys/class/block/, but only in
1307	  /sys/block/.
1308
1309	  This switch is only active when the sysfs.deprecated=1 boot option is
1310	  passed or the SYSFS_DEPRECATED_V2 option is set.
1311
1312	  This option allows new kernels to run on old distributions and tools,
1313	  which might get confused by /sys/class/block/. Since 2007/2008 all
1314	  major distributions and tools handle this just fine.
1315
1316	  Recent distributions and userspace tools after 2009/2010 depend on
1317	  the existence of /sys/class/block/, and will not work with this
1318	  option enabled.
1319
1320	  Only if you are using a new kernel on an old distribution, you might
1321	  need to say Y here.
1322
1323config SYSFS_DEPRECATED_V2
1324	bool "Enable deprecated sysfs features by default"
1325	default n
1326	depends on SYSFS
1327	depends on SYSFS_DEPRECATED
1328	help
1329	  Enable deprecated sysfs by default.
1330
1331	  See the CONFIG_SYSFS_DEPRECATED option for more details about this
1332	  option.
1333
1334	  Only if you are using a new kernel on an old distribution, you might
1335	  need to say Y here. Even then, odds are you would not need it
1336	  enabled, you can always pass the boot option if absolutely necessary.
1337
1338config RELAY
1339	bool "Kernel->user space relay support (formerly relayfs)"
1340	select IRQ_WORK
1341	help
1342	  This option enables support for relay interface support in
1343	  certain file systems (such as debugfs).
1344	  It is designed to provide an efficient mechanism for tools and
1345	  facilities to relay large amounts of data from kernel space to
1346	  user space.
1347
1348	  If unsure, say N.
1349
1350config BLK_DEV_INITRD
1351	bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1352	help
1353	  The initial RAM filesystem is a ramfs which is loaded by the
1354	  boot loader (loadlin or lilo) and that is mounted as root
1355	  before the normal boot procedure. It is typically used to
1356	  load modules needed to mount the "real" root file system,
1357	  etc. See <file:Documentation/admin-guide/initrd.rst> for details.
1358
1359	  If RAM disk support (BLK_DEV_RAM) is also included, this
1360	  also enables initial RAM disk (initrd) support and adds
1361	  15 Kbytes (more on some other architectures) to the kernel size.
1362
1363	  If unsure say Y.
1364
1365if BLK_DEV_INITRD
1366
1367source "usr/Kconfig"
1368
1369endif
1370
1371config BOOT_CONFIG
1372	bool "Boot config support"
1373	select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED
1374	help
1375	  Extra boot config allows system admin to pass a config file as
1376	  complemental extension of kernel cmdline when booting.
1377	  The boot config file must be attached at the end of initramfs
1378	  with checksum, size and magic word.
1379	  See <file:Documentation/admin-guide/bootconfig.rst> for details.
1380
1381	  If unsure, say Y.
1382
1383config BOOT_CONFIG_FORCE
1384	bool "Force unconditional bootconfig processing"
1385	depends on BOOT_CONFIG
1386	default y if BOOT_CONFIG_EMBED
1387	help
1388	  With this Kconfig option set, BOOT_CONFIG processing is carried
1389	  out even when the "bootconfig" kernel-boot parameter is omitted.
1390	  In fact, with this Kconfig option set, there is no way to
1391	  make the kernel ignore the BOOT_CONFIG-supplied kernel-boot
1392	  parameters.
1393
1394	  If unsure, say N.
1395
1396config BOOT_CONFIG_EMBED
1397	bool "Embed bootconfig file in the kernel"
1398	depends on BOOT_CONFIG
1399	help
1400	  Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the
1401	  kernel. Usually, the bootconfig file is loaded with the initrd
1402	  image. But if the system doesn't support initrd, this option will
1403	  help you by embedding a bootconfig file while building the kernel.
1404
1405	  If unsure, say N.
1406
1407config BOOT_CONFIG_EMBED_FILE
1408	string "Embedded bootconfig file path"
1409	depends on BOOT_CONFIG_EMBED
1410	help
1411	  Specify a bootconfig file which will be embedded to the kernel.
1412	  This bootconfig will be used if there is no initrd or no other
1413	  bootconfig in the initrd.
1414
1415config INITRAMFS_PRESERVE_MTIME
1416	bool "Preserve cpio archive mtimes in initramfs"
1417	default y
1418	help
1419	  Each entry in an initramfs cpio archive carries an mtime value. When
1420	  enabled, extracted cpio items take this mtime, with directory mtime
1421	  setting deferred until after creation of any child entries.
1422
1423	  If unsure, say Y.
1424
1425choice
1426	prompt "Compiler optimization level"
1427	default CC_OPTIMIZE_FOR_PERFORMANCE
1428
1429config CC_OPTIMIZE_FOR_PERFORMANCE
1430	bool "Optimize for performance (-O2)"
1431	help
1432	  This is the default optimization level for the kernel, building
1433	  with the "-O2" compiler flag for best performance and most
1434	  helpful compile-time warnings.
1435
1436config CC_OPTIMIZE_FOR_SIZE
1437	bool "Optimize for size (-Os)"
1438	help
1439	  Choosing this option will pass "-Os" to your compiler resulting
1440	  in a smaller kernel.
1441
1442endchoice
1443
1444config HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1445	bool
1446	help
1447	  This requires that the arch annotates or otherwise protects
1448	  its external entry points from being discarded. Linker scripts
1449	  must also merge .text.*, .data.*, and .bss.* correctly into
1450	  output sections. Care must be taken not to pull in unrelated
1451	  sections (e.g., '.text.init'). Typically '.' in section names
1452	  is used to distinguish them from label names / C identifiers.
1453
1454config LD_DEAD_CODE_DATA_ELIMINATION
1455	bool "Dead code and data elimination (EXPERIMENTAL)"
1456	depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1457	depends on EXPERT
1458	depends on $(cc-option,-ffunction-sections -fdata-sections)
1459	depends on $(ld-option,--gc-sections)
1460	help
1461	  Enable this if you want to do dead code and data elimination with
1462	  the linker by compiling with -ffunction-sections -fdata-sections,
1463	  and linking with --gc-sections.
1464
1465	  This can reduce on disk and in-memory size of the kernel
1466	  code and static data, particularly for small configs and
1467	  on small systems. This has the possibility of introducing
1468	  silently broken kernel if the required annotations are not
1469	  present. This option is not well tested yet, so use at your
1470	  own risk.
1471
1472config LD_ORPHAN_WARN
1473	def_bool y
1474	depends on ARCH_WANT_LD_ORPHAN_WARN
1475	depends on $(ld-option,--orphan-handling=warn)
1476	depends on $(ld-option,--orphan-handling=error)
1477
1478config LD_ORPHAN_WARN_LEVEL
1479        string
1480        depends on LD_ORPHAN_WARN
1481        default "error" if WERROR
1482        default "warn"
1483
1484config SYSCTL
1485	bool
1486
1487config HAVE_UID16
1488	bool
1489
1490config SYSCTL_EXCEPTION_TRACE
1491	bool
1492	help
1493	  Enable support for /proc/sys/debug/exception-trace.
1494
1495config SYSCTL_ARCH_UNALIGN_NO_WARN
1496	bool
1497	help
1498	  Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1499	  Allows arch to define/use @no_unaligned_warning to possibly warn
1500	  about unaligned access emulation going on under the hood.
1501
1502config SYSCTL_ARCH_UNALIGN_ALLOW
1503	bool
1504	help
1505	  Enable support for /proc/sys/kernel/unaligned-trap
1506	  Allows arches to define/use @unaligned_enabled to runtime toggle
1507	  the unaligned access emulation.
1508	  see arch/parisc/kernel/unaligned.c for reference
1509
1510config HAVE_PCSPKR_PLATFORM
1511	bool
1512
1513# interpreter that classic socket filters depend on
1514config BPF
1515	bool
1516	select CRYPTO_LIB_SHA1
1517
1518menuconfig EXPERT
1519	bool "Configure standard kernel features (expert users)"
1520	# Unhide debug options, to make the on-by-default options visible
1521	select DEBUG_KERNEL
1522	help
1523	  This option allows certain base kernel options and settings
1524	  to be disabled or tweaked. This is for specialized
1525	  environments which can tolerate a "non-standard" kernel.
1526	  Only use this if you really know what you are doing.
1527
1528config UID16
1529	bool "Enable 16-bit UID system calls" if EXPERT
1530	depends on HAVE_UID16 && MULTIUSER
1531	default y
1532	help
1533	  This enables the legacy 16-bit UID syscall wrappers.
1534
1535config MULTIUSER
1536	bool "Multiple users, groups and capabilities support" if EXPERT
1537	default y
1538	help
1539	  This option enables support for non-root users, groups and
1540	  capabilities.
1541
1542	  If you say N here, all processes will run with UID 0, GID 0, and all
1543	  possible capabilities.  Saying N here also compiles out support for
1544	  system calls related to UIDs, GIDs, and capabilities, such as setuid,
1545	  setgid, and capset.
1546
1547	  If unsure, say Y here.
1548
1549config SGETMASK_SYSCALL
1550	bool "sgetmask/ssetmask syscalls support" if EXPERT
1551	def_bool PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH
1552	help
1553	  sys_sgetmask and sys_ssetmask are obsolete system calls
1554	  no longer supported in libc but still enabled by default in some
1555	  architectures.
1556
1557	  If unsure, leave the default option here.
1558
1559config SYSFS_SYSCALL
1560	bool "Sysfs syscall support" if EXPERT
1561	default y
1562	help
1563	  sys_sysfs is an obsolete system call no longer supported in libc.
1564	  Note that disabling this option is more secure but might break
1565	  compatibility with some systems.
1566
1567	  If unsure say Y here.
1568
1569config FHANDLE
1570	bool "open by fhandle syscalls" if EXPERT
1571	select EXPORTFS
1572	default y
1573	help
1574	  If you say Y here, a user level program will be able to map
1575	  file names to handle and then later use the handle for
1576	  different file system operations. This is useful in implementing
1577	  userspace file servers, which now track files using handles instead
1578	  of names. The handle would remain the same even if file names
1579	  get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
1580	  syscalls.
1581
1582config POSIX_TIMERS
1583	bool "Posix Clocks & timers" if EXPERT
1584	default y
1585	help
1586	  This includes native support for POSIX timers to the kernel.
1587	  Some embedded systems have no use for them and therefore they
1588	  can be configured out to reduce the size of the kernel image.
1589
1590	  When this option is disabled, the following syscalls won't be
1591	  available: timer_create, timer_gettime: timer_getoverrun,
1592	  timer_settime, timer_delete, clock_adjtime, getitimer,
1593	  setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
1594	  clock_getres and clock_nanosleep syscalls will be limited to
1595	  CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
1596
1597	  If unsure say y.
1598
1599config PRINTK
1600	default y
1601	bool "Enable support for printk" if EXPERT
1602	select IRQ_WORK
1603	help
1604	  This option enables normal printk support. Removing it
1605	  eliminates most of the message strings from the kernel image
1606	  and makes the kernel more or less silent. As this makes it
1607	  very difficult to diagnose system problems, saying N here is
1608	  strongly discouraged.
1609
1610config BUG
1611	bool "BUG() support" if EXPERT
1612	default y
1613	help
1614	  Disabling this option eliminates support for BUG and WARN, reducing
1615	  the size of your kernel image and potentially quietly ignoring
1616	  numerous fatal conditions. You should only consider disabling this
1617	  option for embedded systems with no facilities for reporting errors.
1618	  Just say Y.
1619
1620config ELF_CORE
1621	depends on COREDUMP
1622	default y
1623	bool "Enable ELF core dumps" if EXPERT
1624	help
1625	  Enable support for generating core dumps. Disabling saves about 4k.
1626
1627
1628config PCSPKR_PLATFORM
1629	bool "Enable PC-Speaker support" if EXPERT
1630	depends on HAVE_PCSPKR_PLATFORM
1631	select I8253_LOCK
1632	default y
1633	help
1634	  This option allows to disable the internal PC-Speaker
1635	  support, saving some memory.
1636
1637config BASE_FULL
1638	default y
1639	bool "Enable full-sized data structures for core" if EXPERT
1640	help
1641	  Disabling this option reduces the size of miscellaneous core
1642	  kernel data structures. This saves memory on small machines,
1643	  but may reduce performance.
1644
1645config FUTEX
1646	bool "Enable futex support" if EXPERT
1647	depends on !(SPARC32 && SMP)
1648	default y
1649	imply RT_MUTEXES
1650	help
1651	  Disabling this option will cause the kernel to be built without
1652	  support for "fast userspace mutexes".  The resulting kernel may not
1653	  run glibc-based applications correctly.
1654
1655config FUTEX_PI
1656	bool
1657	depends on FUTEX && RT_MUTEXES
1658	default y
1659
1660config EPOLL
1661	bool "Enable eventpoll support" if EXPERT
1662	default y
1663	help
1664	  Disabling this option will cause the kernel to be built without
1665	  support for epoll family of system calls.
1666
1667config SIGNALFD
1668	bool "Enable signalfd() system call" if EXPERT
1669	default y
1670	help
1671	  Enable the signalfd() system call that allows to receive signals
1672	  on a file descriptor.
1673
1674	  If unsure, say Y.
1675
1676config TIMERFD
1677	bool "Enable timerfd() system call" if EXPERT
1678	default y
1679	help
1680	  Enable the timerfd() system call that allows to receive timer
1681	  events on a file descriptor.
1682
1683	  If unsure, say Y.
1684
1685config EVENTFD
1686	bool "Enable eventfd() system call" if EXPERT
1687	default y
1688	help
1689	  Enable the eventfd() system call that allows to receive both
1690	  kernel notification (ie. KAIO) or userspace notifications.
1691
1692	  If unsure, say Y.
1693
1694config SHMEM
1695	bool "Use full shmem filesystem" if EXPERT
1696	default y
1697	depends on MMU
1698	help
1699	  The shmem is an internal filesystem used to manage shared memory.
1700	  It is backed by swap and manages resource limits. It is also exported
1701	  to userspace as tmpfs if TMPFS is enabled. Disabling this
1702	  option replaces shmem and tmpfs with the much simpler ramfs code,
1703	  which may be appropriate on small systems without swap.
1704
1705config AIO
1706	bool "Enable AIO support" if EXPERT
1707	default y
1708	help
1709	  This option enables POSIX asynchronous I/O which may by used
1710	  by some high performance threaded applications. Disabling
1711	  this option saves about 7k.
1712
1713config IO_URING
1714	bool "Enable IO uring support" if EXPERT
1715	select IO_WQ
1716	default y
1717	help
1718	  This option enables support for the io_uring interface, enabling
1719	  applications to submit and complete IO through submission and
1720	  completion rings that are shared between the kernel and application.
1721
1722config ADVISE_SYSCALLS
1723	bool "Enable madvise/fadvise syscalls" if EXPERT
1724	default y
1725	help
1726	  This option enables the madvise and fadvise syscalls, used by
1727	  applications to advise the kernel about their future memory or file
1728	  usage, improving performance. If building an embedded system where no
1729	  applications use these syscalls, you can disable this option to save
1730	  space.
1731
1732config MEMBARRIER
1733	bool "Enable membarrier() system call" if EXPERT
1734	default y
1735	help
1736	  Enable the membarrier() system call that allows issuing memory
1737	  barriers across all running threads, which can be used to distribute
1738	  the cost of user-space memory barriers asymmetrically by transforming
1739	  pairs of memory barriers into pairs consisting of membarrier() and a
1740	  compiler barrier.
1741
1742	  If unsure, say Y.
1743
1744config KALLSYMS
1745	bool "Load all symbols for debugging/ksymoops" if EXPERT
1746	default y
1747	help
1748	  Say Y here to let the kernel print out symbolic crash information and
1749	  symbolic stack backtraces. This increases the size of the kernel
1750	  somewhat, as all symbols have to be loaded into the kernel image.
1751
1752config KALLSYMS_SELFTEST
1753	bool "Test the basic functions and performance of kallsyms"
1754	depends on KALLSYMS
1755	default n
1756	help
1757	  Test the basic functions and performance of some interfaces, such as
1758	  kallsyms_lookup_name. It also calculates the compression rate of the
1759	  kallsyms compression algorithm for the current symbol set.
1760
1761	  Start self-test automatically after system startup. Suggest executing
1762	  "dmesg | grep kallsyms_selftest" to collect test results. "finish" is
1763	  displayed in the last line, indicating that the test is complete.
1764
1765config KALLSYMS_ALL
1766	bool "Include all symbols in kallsyms"
1767	depends on DEBUG_KERNEL && KALLSYMS
1768	help
1769	  Normally kallsyms only contains the symbols of functions for nicer
1770	  OOPS messages and backtraces (i.e., symbols from the text and inittext
1771	  sections). This is sufficient for most cases. And only if you want to
1772	  enable kernel live patching, or other less common use cases (e.g.,
1773	  when a debugger is used) all symbols are required (i.e., names of
1774	  variables from the data sections, etc).
1775
1776	  This option makes sure that all symbols are loaded into the kernel
1777	  image (i.e., symbols from all sections) in cost of increased kernel
1778	  size (depending on the kernel configuration, it may be 300KiB or
1779	  something like this).
1780
1781	  Say N unless you really need all symbols, or kernel live patching.
1782
1783config KALLSYMS_ABSOLUTE_PERCPU
1784	bool
1785	depends on KALLSYMS
1786	default X86_64 && SMP
1787
1788config KALLSYMS_BASE_RELATIVE
1789	bool
1790	depends on KALLSYMS
1791	default !IA64
1792	help
1793	  Instead of emitting them as absolute values in the native word size,
1794	  emit the symbol references in the kallsyms table as 32-bit entries,
1795	  each containing a relative value in the range [base, base + U32_MAX]
1796	  or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either
1797	  an absolute value in the range [0, S32_MAX] or a relative value in the
1798	  range [base, base + S32_MAX], where base is the lowest relative symbol
1799	  address encountered in the image.
1800
1801	  On 64-bit builds, this reduces the size of the address table by 50%,
1802	  but more importantly, it results in entries whose values are build
1803	  time constants, and no relocation pass is required at runtime to fix
1804	  up the entries based on the runtime load address of the kernel.
1805
1806# end of the "standard kernel features (expert users)" menu
1807
1808# syscall, maps, verifier
1809
1810config ARCH_HAS_MEMBARRIER_CALLBACKS
1811	bool
1812
1813config ARCH_HAS_MEMBARRIER_SYNC_CORE
1814	bool
1815
1816config KCMP
1817	bool "Enable kcmp() system call" if EXPERT
1818	help
1819	  Enable the kernel resource comparison system call. It provides
1820	  user-space with the ability to compare two processes to see if they
1821	  share a common resource, such as a file descriptor or even virtual
1822	  memory space.
1823
1824	  If unsure, say N.
1825
1826config RSEQ
1827	bool "Enable rseq() system call" if EXPERT
1828	default y
1829	depends on HAVE_RSEQ
1830	select MEMBARRIER
1831	help
1832	  Enable the restartable sequences system call. It provides a
1833	  user-space cache for the current CPU number value, which
1834	  speeds up getting the current CPU number from user-space,
1835	  as well as an ABI to speed up user-space operations on
1836	  per-CPU data.
1837
1838	  If unsure, say Y.
1839
1840config DEBUG_RSEQ
1841	default n
1842	bool "Enabled debugging of rseq() system call" if EXPERT
1843	depends on RSEQ && DEBUG_KERNEL
1844	help
1845	  Enable extra debugging checks for the rseq system call.
1846
1847	  If unsure, say N.
1848
1849config EMBEDDED
1850	bool "Embedded system"
1851	select EXPERT
1852	help
1853	  This option should be enabled if compiling the kernel for
1854	  an embedded system so certain expert options are available
1855	  for configuration.
1856
1857config HAVE_PERF_EVENTS
1858	bool
1859	help
1860	  See tools/perf/design.txt for details.
1861
1862config GUEST_PERF_EVENTS
1863	bool
1864	depends on HAVE_PERF_EVENTS
1865
1866config PERF_USE_VMALLOC
1867	bool
1868	help
1869	  See tools/perf/design.txt for details
1870
1871config PC104
1872	bool "PC/104 support" if EXPERT
1873	help
1874	  Expose PC/104 form factor device drivers and options available for
1875	  selection and configuration. Enable this option if your target
1876	  machine has a PC/104 bus.
1877
1878menu "Kernel Performance Events And Counters"
1879
1880config PERF_EVENTS
1881	bool "Kernel performance events and counters"
1882	default y if PROFILING
1883	depends on HAVE_PERF_EVENTS
1884	select IRQ_WORK
1885	help
1886	  Enable kernel support for various performance events provided
1887	  by software and hardware.
1888
1889	  Software events are supported either built-in or via the
1890	  use of generic tracepoints.
1891
1892	  Most modern CPUs support performance events via performance
1893	  counter registers. These registers count the number of certain
1894	  types of hw events: such as instructions executed, cachemisses
1895	  suffered, or branches mis-predicted - without slowing down the
1896	  kernel or applications. These registers can also trigger interrupts
1897	  when a threshold number of events have passed - and can thus be
1898	  used to profile the code that runs on that CPU.
1899
1900	  The Linux Performance Event subsystem provides an abstraction of
1901	  these software and hardware event capabilities, available via a
1902	  system call and used by the "perf" utility in tools/perf/. It
1903	  provides per task and per CPU counters, and it provides event
1904	  capabilities on top of those.
1905
1906	  Say Y if unsure.
1907
1908config DEBUG_PERF_USE_VMALLOC
1909	default n
1910	bool "Debug: use vmalloc to back perf mmap() buffers"
1911	depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
1912	select PERF_USE_VMALLOC
1913	help
1914	  Use vmalloc memory to back perf mmap() buffers.
1915
1916	  Mostly useful for debugging the vmalloc code on platforms
1917	  that don't require it.
1918
1919	  Say N if unsure.
1920
1921endmenu
1922
1923config SYSTEM_DATA_VERIFICATION
1924	def_bool n
1925	select SYSTEM_TRUSTED_KEYRING
1926	select KEYS
1927	select CRYPTO
1928	select CRYPTO_RSA
1929	select ASYMMETRIC_KEY_TYPE
1930	select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1931	select ASN1
1932	select OID_REGISTRY
1933	select X509_CERTIFICATE_PARSER
1934	select PKCS7_MESSAGE_PARSER
1935	help
1936	  Provide PKCS#7 message verification using the contents of the system
1937	  trusted keyring to provide public keys.  This then can be used for
1938	  module verification, kexec image verification and firmware blob
1939	  verification.
1940
1941config PROFILING
1942	bool "Profiling support"
1943	help
1944	  Say Y here to enable the extended profiling support mechanisms used
1945	  by profilers.
1946
1947config RUST
1948	bool "Rust support"
1949	depends on HAVE_RUST
1950	depends on RUST_IS_AVAILABLE
1951	depends on !MODVERSIONS
1952	depends on !GCC_PLUGINS
1953	depends on !RANDSTRUCT
1954	depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
1955	select CONSTRUCTORS
1956	help
1957	  Enables Rust support in the kernel.
1958
1959	  This allows other Rust-related options, like drivers written in Rust,
1960	  to be selected.
1961
1962	  It is also required to be able to load external kernel modules
1963	  written in Rust.
1964
1965	  See Documentation/rust/ for more information.
1966
1967	  If unsure, say N.
1968
1969config RUSTC_VERSION_TEXT
1970	string
1971	depends on RUST
1972	default $(shell,command -v $(RUSTC) >/dev/null 2>&1 && $(RUSTC) --version || echo n)
1973
1974config BINDGEN_VERSION_TEXT
1975	string
1976	depends on RUST
1977	default $(shell,command -v $(BINDGEN) >/dev/null 2>&1 && $(BINDGEN) --version || echo n)
1978
1979#
1980# Place an empty function call at each tracepoint site. Can be
1981# dynamically changed for a probe function.
1982#
1983config TRACEPOINTS
1984	bool
1985
1986endmenu		# General setup
1987
1988source "arch/Kconfig"
1989
1990config RT_MUTEXES
1991	bool
1992	default y if PREEMPT_RT
1993
1994config BASE_SMALL
1995	int
1996	default 0 if BASE_FULL
1997	default 1 if !BASE_FULL
1998
1999config MODULE_SIG_FORMAT
2000	def_bool n
2001	select SYSTEM_DATA_VERIFICATION
2002
2003source "kernel/module/Kconfig"
2004
2005config INIT_ALL_POSSIBLE
2006	bool
2007	help
2008	  Back when each arch used to define their own cpu_online_mask and
2009	  cpu_possible_mask, some of them chose to initialize cpu_possible_mask
2010	  with all 1s, and others with all 0s.  When they were centralised,
2011	  it was better to provide this option than to break all the archs
2012	  and have several arch maintainers pursuing me down dark alleys.
2013
2014source "block/Kconfig"
2015
2016config PREEMPT_NOTIFIERS
2017	bool
2018
2019config PADATA
2020	depends on SMP
2021	bool
2022
2023config ASN1
2024	tristate
2025	help
2026	  Build a simple ASN.1 grammar compiler that produces a bytecode output
2027	  that can be interpreted by the ASN.1 stream decoder and used to
2028	  inform it as to what tags are to be expected in a stream and what
2029	  functions to call on what tags.
2030
2031source "kernel/Kconfig.locks"
2032
2033config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
2034	bool
2035
2036config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
2037	bool
2038
2039# It may be useful for an architecture to override the definitions of the
2040# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h>
2041# and the COMPAT_ variants in <linux/compat.h>, in particular to use a
2042# different calling convention for syscalls. They can also override the
2043# macros for not-implemented syscalls in kernel/sys_ni.c and
2044# kernel/time/posix-stubs.c. All these overrides need to be available in
2045# <asm/syscall_wrapper.h>.
2046config ARCH_HAS_SYSCALL_WRAPPER
2047	def_bool n
2048