xref: /linux/init/Kconfig (revision 9e7dc228bb6d4afa74dd6bab4f3aad43126cc2db)
1ec8f24b7SThomas Gleixner# SPDX-License-Identifier: GPL-2.0-only
28b59cd81SMasahiro Yamadaconfig CC_VERSION_TEXT
38b59cd81SMasahiro Yamada	string
48b59cd81SMasahiro Yamada	default "$(CC_VERSION_TEXT)"
58b59cd81SMasahiro Yamada	help
68b59cd81SMasahiro Yamada	  This is used in unclear ways:
78b59cd81SMasahiro Yamada
88b59cd81SMasahiro Yamada	  - Re-run Kconfig when the compiler is updated
98b59cd81SMasahiro Yamada	    The 'default' property references the environment variable,
108b59cd81SMasahiro Yamada	    CC_VERSION_TEXT so it is recorded in include/config/auto.conf.cmd.
118b59cd81SMasahiro Yamada	    When the compiler is updated, Kconfig will be invoked.
128b59cd81SMasahiro Yamada
13f9c8bc46SBhaskar Chowdhury	  - Ensure full rebuild when the compiler is updated
14ce6ed1c4SMasahiro Yamada	    include/linux/compiler-version.h contains this option in the comment
150e0345b7SAlexey Dobriyan	    line so fixdep adds include/config/CC_VERSION_TEXT into the
16ce6ed1c4SMasahiro Yamada	    auto-generated dependency. When the compiler is updated, syncconfig
17ce6ed1c4SMasahiro Yamada	    will touch it and then every file will be rebuilt.
188b59cd81SMasahiro Yamada
19a4353898SMasahiro Yamadaconfig CC_IS_GCC
20aec6c60aSMasahiro Yamada	def_bool $(success,test "$(cc-name)" = GCC)
21a4353898SMasahiro Yamada
22a4353898SMasahiro Yamadaconfig GCC_VERSION
23a4353898SMasahiro Yamada	int
24aec6c60aSMasahiro Yamada	default $(cc-version) if CC_IS_GCC
25a4353898SMasahiro Yamada	default 0
26a4353898SMasahiro Yamada
27469cb737SMasahiro Yamadaconfig CC_IS_CLANG
28aec6c60aSMasahiro Yamada	def_bool $(success,test "$(cc-name)" = Clang)
29b744b43fSSami Tolvanen
30469cb737SMasahiro Yamadaconfig CLANG_VERSION
31469cb737SMasahiro Yamada	int
32aec6c60aSMasahiro Yamada	default $(cc-version) if CC_IS_CLANG
33aec6c60aSMasahiro Yamada	default 0
34469cb737SMasahiro Yamada
35ba64beb1SMasahiro Yamadaconfig AS_IS_GNU
36ba64beb1SMasahiro Yamada	def_bool $(success,test "$(as-name)" = GNU)
37ba64beb1SMasahiro Yamada
38ba64beb1SMasahiro Yamadaconfig AS_IS_LLVM
39ba64beb1SMasahiro Yamada	def_bool $(success,test "$(as-name)" = LLVM)
40ba64beb1SMasahiro Yamada
41ba64beb1SMasahiro Yamadaconfig AS_VERSION
42ba64beb1SMasahiro Yamada	int
43ba64beb1SMasahiro Yamada	# Use clang version if this is the integrated assembler
44ba64beb1SMasahiro Yamada	default CLANG_VERSION if AS_IS_LLVM
45ba64beb1SMasahiro Yamada	default $(as-version)
46ba64beb1SMasahiro Yamada
4702aff859SMasahiro Yamadaconfig LD_IS_BFD
4802aff859SMasahiro Yamada	def_bool $(success,test "$(ld-name)" = BFD)
4902aff859SMasahiro Yamada
5002aff859SMasahiro Yamadaconfig LD_VERSION
5102aff859SMasahiro Yamada	int
5202aff859SMasahiro Yamada	default $(ld-version) if LD_IS_BFD
5302aff859SMasahiro Yamada	default 0
5402aff859SMasahiro Yamada
5502aff859SMasahiro Yamadaconfig LD_IS_LLD
5602aff859SMasahiro Yamada	def_bool $(success,test "$(ld-name)" = LLD)
57c65eacbeSAndy Lutomirski
58d5750cd3SNathan Chancellorconfig LLD_VERSION
59d5750cd3SNathan Chancellor	int
6002aff859SMasahiro Yamada	default $(ld-version) if LD_IS_LLD
6102aff859SMasahiro Yamada	default 0
62d5750cd3SNathan Chancellor
636e74c6b5SMiguel Ojedaconfig RUSTC_VERSION
646e74c6b5SMiguel Ojeda	int
65af0121c2SGary Guo	default $(rustc-version)
666e74c6b5SMiguel Ojeda	help
676e74c6b5SMiguel Ojeda	  It does not depend on `RUST` since that one may need to use the version
686e74c6b5SMiguel Ojeda	  in a `depends on`.
696e74c6b5SMiguel Ojeda
702f7ab126SMiguel Ojedaconfig RUST_IS_AVAILABLE
712f7ab126SMiguel Ojeda	def_bool $(success,$(srctree)/scripts/rust_is_available.sh)
722f7ab126SMiguel Ojeda	help
732f7ab126SMiguel Ojeda	  This shows whether a suitable Rust toolchain is available (found).
742f7ab126SMiguel Ojeda
752f7ab126SMiguel Ojeda	  Please see Documentation/rust/quick-start.rst for instructions on how
76eacf96d2SColin Ian King	  to satisfy the build requirements of Rust support.
772f7ab126SMiguel Ojeda
782f7ab126SMiguel Ojeda	  In particular, the Makefile target 'rustavailable' is useful to check
792f7ab126SMiguel Ojeda	  why the Rust toolchain is not being detected.
802f7ab126SMiguel Ojeda
81af0121c2SGary Guoconfig RUSTC_LLVM_VERSION
82af0121c2SGary Guo	int
83af0121c2SGary Guo	default $(rustc-llvm-version)
84af0121c2SGary Guo
85deab487eSThomas Weißschuhconfig ARCH_HAS_CC_CAN_LINK
86deab487eSThomas Weißschuh	bool
87deab487eSThomas Weißschuh
881a927fd3SMasahiro Yamadaconfig CC_CAN_LINK
899371f86eSMasahiro Yamada	bool
90deab487eSThomas Weißschuh	default ARCH_CC_CAN_LINK if ARCH_HAS_CC_CAN_LINK
9180623f2cSThomas Weißschuh	default $(cc_can_link_user,$(m64-flag)) if 64BIT
9280623f2cSThomas Weißschuh	default $(cc_can_link_user,$(m32-flag))
931a927fd3SMasahiro Yamada
94f2f6a8e8SMark Rutland# Fixed in GCC 14, 13.3, 12.4 and 11.5
95f2f6a8e8SMark Rutland# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113921
96f2f6a8e8SMark Rutlandconfig GCC_ASM_GOTO_OUTPUT_BROKEN
97f2f6a8e8SMark Rutland	bool
98f2f6a8e8SMark Rutland	depends on CC_IS_GCC
99f2f6a8e8SMark Rutland	default y if GCC_VERSION < 110500
100f2f6a8e8SMark Rutland	default y if GCC_VERSION >= 120000 && GCC_VERSION < 120400
101f2f6a8e8SMark Rutland	default y if GCC_VERSION >= 130000 && GCC_VERSION < 130300
102f2f6a8e8SMark Rutland
103587f1701SNick Desaulniersconfig CC_HAS_ASM_GOTO_OUTPUT
104f2f6a8e8SMark Rutland	def_bool y
105f2f6a8e8SMark Rutland	depends on !GCC_ASM_GOTO_OUTPUT_BROKEN
106e2ffa15bSThomas Gleixner	# Detect basic support
107f2f6a8e8SMark Rutland	depends on $(success,echo 'int foo(int x) { asm goto ("": "=r"(x) ::: bar); return x; bar: return 0; }' | $(CC) -x c - -c -o /dev/null)
108e2ffa15bSThomas Gleixner	# Detect clang (< v17) scoped label issues
109fde0ab43SLinus Torvalds	depends on $(success,echo 'void b(void **);void* c(void);int f(void){{asm goto(""::::l0);return 0;l0:return 1;}void *x __attribute__((cleanup(b)))=c();{asm goto(""::::l1);return 2;l1:return 3;}}' | $(CC) -x c - -c -o /dev/null)
110587f1701SNick Desaulniers
1111aa0e8b1SSean Christophersonconfig CC_HAS_ASM_GOTO_TIED_OUTPUT
1121aa0e8b1SSean Christopherson	depends on CC_HAS_ASM_GOTO_OUTPUT
1131aa0e8b1SSean Christopherson	# Detect buggy gcc and clang, fixed in gcc-11 clang-14.
114534bd703SAlexandre Belloni	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)
1151aa0e8b1SSean Christopherson
1165cf896fbSPeter Collingbourneconfig TOOLS_SUPPORT_RELR
1172d122942SWill Deacon	def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh)
1185cf896fbSPeter Collingbourne
119eb111869SRasmus Villemoesconfig CC_HAS_ASM_INLINE
120eb111869SRasmus Villemoes	def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null)
121eb111869SRasmus Villemoes
122f72e2cffSHeiko Carstensconfig CC_HAS_ASSUME
123f72e2cffSHeiko Carstens	bool
124f72e2cffSHeiko Carstens	# clang needs to be at least 19.1.0 since the meaning of the assume
125f72e2cffSHeiko Carstens	# attribute changed:
126f72e2cffSHeiko Carstens	# https://github.com/llvm/llvm-project/commit/c44fa3e8a9a44c2e9a575768a3c185354b9f6c17
127f72e2cffSHeiko Carstens	default y if CC_IS_CLANG && CLANG_VERSION >= 190100
128f72e2cffSHeiko Carstens	# supported since gcc 13.1.0
129f72e2cffSHeiko Carstens	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106654
130f72e2cffSHeiko Carstens	default y if CC_IS_GCC && GCC_VERSION >= 130100
131f72e2cffSHeiko Carstens
13251c2ee6dSNick Desaulniersconfig CC_HAS_NO_PROFILE_FN_ATTR
13351c2ee6dSNick Desaulniers	def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror)
13451c2ee6dSNick Desaulniers
135f06e108aSJan Hendrik Farrconfig CC_HAS_COUNTED_BY
1365106c650SJan Hendrik Farr	bool
13786a9b125SNathan Chancellor	# clang needs to be at least 20.1.0 to avoid potential crashes
13886a9b125SNathan Chancellor	# when building structures that contain __counted_by
13986a9b125SNathan Chancellor	# https://github.com/ClangBuiltLinux/linux/issues/2114
14086a9b125SNathan Chancellor	# https://github.com/llvm/llvm-project/commit/160fb1121cdf703c3ef5e61fb26c5659eb581489
14186a9b125SNathan Chancellor	default y if CC_IS_CLANG && CLANG_VERSION >= 200100
1425106c650SJan Hendrik Farr	# supported since gcc 15.1.0
1435106c650SJan Hendrik Farr	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896
1445106c650SJan Hendrik Farr	default y if CC_IS_GCC && GCC_VERSION >= 150100
145f06e108aSJan Hendrik Farr
146150a04d8SBill Wendlingconfig CC_HAS_COUNTED_BY_PTR
147150a04d8SBill Wendling	bool
148150a04d8SBill Wendling	# supported since clang 22
149150a04d8SBill Wendling	default y if CC_IS_CLANG && CLANG_VERSION >= 220000
150150a04d8SBill Wendling	# supported since gcc 16.0.0
151150a04d8SBill Wendling	default y if CC_IS_GCC && GCC_VERSION >= 160000
152150a04d8SBill Wendling
153b688f369SKees Cookconfig CC_HAS_MULTIDIMENSIONAL_NONSTRING
154b688f369SKees Cook	def_bool $(success,echo 'char tag[][4] __attribute__((__nonstring__)) = { };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror)
155b688f369SKees Cook
156e7607f7dSNathan Chancellorconfig LD_CAN_USE_KEEP_IN_OVERLAY
157e7607f7dSNathan Chancellor	# ld.lld prior to 21.0.0 did not support KEEP within an overlay description
158e7607f7dSNathan Chancellor	# https://github.com/llvm/llvm-project/pull/130661
159e7607f7dSNathan Chancellor	def_bool LD_IS_BFD || LLD_VERSION >= 210000
160e7607f7dSNathan Chancellor
16188622323SAlexandre Courbotconfig RUSTC_HAS_SLICE_AS_FLATTENED
16288622323SAlexandre Courbot	def_bool RUSTC_VERSION >= 108000
16388622323SAlexandre Courbot
16447cb6bf7SXiangfei Dingconfig RUSTC_HAS_COERCE_POINTEE
16547cb6bf7SXiangfei Ding	def_bool RUSTC_VERSION >= 108400
16647cb6bf7SXiangfei Ding
16736174d16SMiguel Ojedaconfig RUSTC_HAS_SPAN_FILE
16836174d16SMiguel Ojeda	def_bool RUSTC_VERSION >= 108800
16936174d16SMiguel Ojeda
1707129ea6eSMiguel Ojedaconfig RUSTC_HAS_UNNECESSARY_TRANSMUTES
1717129ea6eSMiguel Ojeda	def_bool RUSTC_VERSION >= 108800
1727129ea6eSMiguel Ojeda
1730aa2b78cSBoqun Fengconfig RUSTC_HAS_FILE_WITH_NUL
1740aa2b78cSBoqun Feng	def_bool RUSTC_VERSION >= 108900
1750aa2b78cSBoqun Feng
176c09461a0SAlice Ryhlconfig RUSTC_HAS_FILE_AS_C_STR
177c09461a0SAlice Ryhl	def_bool RUSTC_VERSION >= 109100
178c09461a0SAlice Ryhl
179613fe169SNathan Chancellorconfig PAHOLE_VERSION
180613fe169SNathan Chancellor	int
18190e5b38aSIhor Solodrai	default "$(PAHOLE_VERSION)"
182613fe169SNathan Chancellor
183b99b87f7SPeter Oberparleiterconfig CONSTRUCTORS
184b99b87f7SPeter Oberparleiter	bool
185b99b87f7SPeter Oberparleiter
186e360adbeSPeter Zijlstraconfig IRQ_WORK
187fd0a68a2STejun Heo	def_bool y if SMP
188e360adbeSPeter Zijlstra
18910916706SShile Zhangconfig BUILDTIME_TABLE_SORT
1901dbdc6f1SDavid Daney	bool
1911dbdc6f1SDavid Daney
192c65eacbeSAndy Lutomirskiconfig THREAD_INFO_IN_TASK
193c65eacbeSAndy Lutomirski	bool
194c65eacbeSAndy Lutomirski	help
195c65eacbeSAndy Lutomirski	  Select this to move thread_info off the stack into task_struct.  To
196c65eacbeSAndy Lutomirski	  make this work, an arch will need to remove all thread_info fields
197c65eacbeSAndy Lutomirski	  except flags and fix any runtime bugs.
198c65eacbeSAndy Lutomirski
199c6c314a6SAndy Lutomirski	  One subtle change that will be needed is to use try_get_task_stack()
200c6c314a6SAndy Lutomirski	  and put_task_stack() in save_thread_stack_tsk() and get_wchan().
201c6c314a6SAndy Lutomirski
202ff0cfc66SAl Boldimenu "General setup"
2031da177e4SLinus Torvalds
2041da177e4SLinus Torvaldsconfig BROKEN
2051da177e4SLinus Torvalds	bool
206fefbeed8SAndrew Morton	help
207fefbeed8SAndrew Morton	  This option allows you to choose whether you want to try to
208fefbeed8SAndrew Morton	  compile (and fix) old drivers that haven't been updated to
209fefbeed8SAndrew Morton	  new infrastructure.
2101da177e4SLinus Torvalds
2111da177e4SLinus Torvaldsconfig BROKEN_ON_SMP
2121da177e4SLinus Torvalds	bool
2131da177e4SLinus Torvalds	depends on BROKEN || !SMP
2141da177e4SLinus Torvalds	default y
2151da177e4SLinus Torvalds
2161da177e4SLinus Torvaldsconfig INIT_ENV_ARG_LIMIT
2171da177e4SLinus Torvalds	int
218dd673bcaSAdrian Bunk	default 32 if !UML
219dd673bcaSAdrian Bunk	default 128 if UML
2201da177e4SLinus Torvalds	help
22134ad92c2SRandy Dunlap	  Maximum of each of the number of arguments and environment
22234ad92c2SRandy Dunlap	  variables passed to init from the kernel command line.
2231da177e4SLinus Torvalds
2244bb16672SJiri Slabyconfig COMPILE_TEST
2254bb16672SJiri Slaby	bool "Compile also drivers which will not load"
226ea29b20aSMasahiro Yamada	depends on HAS_IOMEM
2274bb16672SJiri Slaby	help
2284bb16672SJiri Slaby	  Some drivers can be compiled on a different platform than they are
2294bb16672SJiri Slaby	  intended to be run on. Despite they cannot be loaded there (or even
2304bb16672SJiri Slaby	  when they load they cannot be used due to missing HW support),
2314bb16672SJiri Slaby	  developers still, opposing to distributors, might want to build such
2324bb16672SJiri Slaby	  drivers to compile-test them.
2334bb16672SJiri Slaby
2344bb16672SJiri Slaby	  If you are a developer and want to build everything available, say Y
2354bb16672SJiri Slaby	  here. If you are a user/distributor, say N here to exclude useless
2364bb16672SJiri Slaby	  drivers to be distributed.
2374bb16672SJiri Slaby
2383fe617ccSLinus Torvaldsconfig WERROR
2393fe617ccSLinus Torvalds	bool "Compile the kernel with warnings as errors"
240b339ec9cSMarco Elver	default COMPILE_TEST
2413fe617ccSLinus Torvalds	help
2423fe617ccSLinus Torvalds	  A kernel build should not cause any compiler warnings, and this
2432f7ab126SMiguel Ojeda	  enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags
244e1789d7cSXin Li	  to enforce that rule by default. Certain warnings from other tools
245e1789d7cSXin Li	  such as the linker may be upgraded to errors with this option as
246e1789d7cSXin Li	  well.
2473fe617ccSLinus Torvalds
248e1789d7cSXin Li	  However, if you have a new (or very old) compiler or linker with odd
249e1789d7cSXin Li	  and unusual warnings, or you have some architecture with problems,
2503fe617ccSLinus Torvalds	  you may need to disable this config option in order to
2513fe617ccSLinus Torvalds	  successfully build the kernel.
2523fe617ccSLinus Torvalds
2533fe617ccSLinus Torvalds	  If in doubt, say Y.
2543fe617ccSLinus Torvalds
255d6fc9fcbSMasahiro Yamadaconfig UAPI_HEADER_TEST
256d6fc9fcbSMasahiro Yamada	bool "Compile test UAPI headers"
2572a0a3080SThomas Weißschuh	depends on HEADERS_INSTALL
258d6fc9fcbSMasahiro Yamada	help
259d6fc9fcbSMasahiro Yamada	  Compile test headers exported to user-space to ensure they are
260d6fc9fcbSMasahiro Yamada	  self-contained, i.e. compilable as standalone units.
261d6fc9fcbSMasahiro Yamada
262d6fc9fcbSMasahiro Yamada	  If you are a developer or tester and want to ensure the exported
263d6fc9fcbSMasahiro Yamada	  headers are self-contained, say Y here. Otherwise, choose N.
264d6fc9fcbSMasahiro Yamada
2651da177e4SLinus Torvaldsconfig LOCALVERSION
2661da177e4SLinus Torvalds	string "Local version - append to kernel release"
2671da177e4SLinus Torvalds	help
2681da177e4SLinus Torvalds	  Append an extra string to the end of your kernel version.
2691da177e4SLinus Torvalds	  This will show up when you type uname, for example.
2701da177e4SLinus Torvalds	  The string you set here will be appended after the contents of
2711da177e4SLinus Torvalds	  any files with a filename matching localversion* in your
2721da177e4SLinus Torvalds	  object and source tree, in that order.  Your total string can
2731da177e4SLinus Torvalds	  be a maximum of 64 characters.
2741da177e4SLinus Torvalds
275aaebf433SRyan Andersonconfig LOCALVERSION_AUTO
276aaebf433SRyan Anderson	bool "Automatically append version information to the version string"
277aaebf433SRyan Anderson	default y
278ac3339baSAlexey Dobriyan	depends on !COMPILE_TEST
279aaebf433SRyan Anderson	help
280aaebf433SRyan Anderson	  This will try to automatically determine if the current tree is a
2816e5a5420SRobert P. J. Day	  release tree by looking for git tags that belong to the current
2826e5a5420SRobert P. J. Day	  top of tree revision.
283aaebf433SRyan Anderson
284aaebf433SRyan Anderson	  A string of the format -gxxxxxxxx will be added to the localversion
2856e5a5420SRobert P. J. Day	  if a git-based tree is found.  The string generated by this will be
286aaebf433SRyan Anderson	  appended after any matching localversion* files, and after the value
2876e5a5420SRobert P. J. Day	  set in CONFIG_LOCALVERSION.
288aaebf433SRyan Anderson
2890f9c608dSRasmus Villemoes	  (The actual string used here is the first 12 characters produced
2906e5a5420SRobert P. J. Day	  by running the command:
2916e5a5420SRobert P. J. Day
2926e5a5420SRobert P. J. Day	    $ git rev-parse --verify HEAD
2936e5a5420SRobert P. J. Day
2946e5a5420SRobert P. J. Day	  which is done within the script "scripts/setlocalversion".)
295aaebf433SRyan Anderson
2969afb719eSLaura Abbottconfig BUILD_SALT
2979afb719eSLaura Abbott	string "Build ID Salt"
2989afb719eSLaura Abbott	default ""
2999afb719eSLaura Abbott	help
3009afb719eSLaura Abbott	  The build ID is used to link binaries and their debug info. Setting
3019afb719eSLaura Abbott	  this option will use the value in the calculation of the build id.
3029afb719eSLaura Abbott	  This is mostly useful for distributions which want to ensure the
3039afb719eSLaura Abbott	  build is unique between builds. It's safe to leave the default.
3049afb719eSLaura Abbott
3052e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_GZIP
3062e9f3bddSH. Peter Anvin	bool
3072e9f3bddSH. Peter Anvin
3082e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_BZIP2
3092e9f3bddSH. Peter Anvin	bool
3102e9f3bddSH. Peter Anvin
3112e9f3bddSH. Peter Anvinconfig HAVE_KERNEL_LZMA
3122e9f3bddSH. Peter Anvin	bool
3132e9f3bddSH. Peter Anvin
3143ebe1243SLasse Collinconfig HAVE_KERNEL_XZ
3153ebe1243SLasse Collin	bool
3163ebe1243SLasse Collin
3177dd65febSAlbin Tonnerreconfig HAVE_KERNEL_LZO
3187dd65febSAlbin Tonnerre	bool
3197dd65febSAlbin Tonnerre
320e76e1fdfSKyungsik Leeconfig HAVE_KERNEL_LZ4
321e76e1fdfSKyungsik Lee	bool
322e76e1fdfSKyungsik Lee
32348f7ddf7SNick Terrellconfig HAVE_KERNEL_ZSTD
32448f7ddf7SNick Terrell	bool
32548f7ddf7SNick Terrell
326f16466afSVasily Gorbikconfig HAVE_KERNEL_UNCOMPRESSED
327f16466afSVasily Gorbik	bool
328f16466afSVasily Gorbik
32930d65dbfSAlain Knaffchoice
33030d65dbfSAlain Knaff	prompt "Kernel compression mode"
33130d65dbfSAlain Knaff	default KERNEL_GZIP
33248f7ddf7SNick Terrell	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
33330d65dbfSAlain Knaff	help
33430d65dbfSAlain Knaff	  The linux kernel is a kind of self-extracting executable.
33530d65dbfSAlain Knaff	  Several compression algorithms are available, which differ
33630d65dbfSAlain Knaff	  in efficiency, compression and decompression speed.
33730d65dbfSAlain Knaff	  Compression speed is only relevant when building a kernel.
33830d65dbfSAlain Knaff	  Decompression speed is relevant at each boot.
33930d65dbfSAlain Knaff
34030d65dbfSAlain Knaff	  If you have any problems with bzip2 or lzma compressed
34130d65dbfSAlain Knaff	  kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
34230d65dbfSAlain Knaff	  version of this functionality (bzip2 only), for 2.4, was
34330d65dbfSAlain Knaff	  supplied by Christian Ludwig)
34430d65dbfSAlain Knaff
34530d65dbfSAlain Knaff	  High compression options are mostly useful for users, who
34630d65dbfSAlain Knaff	  are low on disk space (embedded systems), but for whom ram
34730d65dbfSAlain Knaff	  size matters less.
34830d65dbfSAlain Knaff
34930d65dbfSAlain Knaff	  If in doubt, select 'gzip'
35030d65dbfSAlain Knaff
35130d65dbfSAlain Knaffconfig KERNEL_GZIP
35230d65dbfSAlain Knaff	bool "Gzip"
3532e9f3bddSH. Peter Anvin	depends on HAVE_KERNEL_GZIP
35430d65dbfSAlain Knaff	help
3557dd65febSAlbin Tonnerre	  The old and tried gzip compression. It provides a good balance
3567dd65febSAlbin Tonnerre	  between compression ratio and decompression speed.
35730d65dbfSAlain Knaff
35830d65dbfSAlain Knaffconfig KERNEL_BZIP2
35930d65dbfSAlain Knaff	bool "Bzip2"
3602e9f3bddSH. Peter Anvin	depends on HAVE_KERNEL_BZIP2
36130d65dbfSAlain Knaff	help
36230d65dbfSAlain Knaff	  Its compression ratio and speed is intermediate.
3630a4dd35cSRandy Dunlap	  Decompression speed is slowest among the choices.  The kernel
3642e9f3bddSH. Peter Anvin	  size is about 10% smaller with bzip2, in comparison to gzip.
3652e9f3bddSH. Peter Anvin	  Bzip2 uses a large amount of memory. For modern kernels you
3662e9f3bddSH. Peter Anvin	  will need at least 8MB RAM or more for booting.
36730d65dbfSAlain Knaff
36830d65dbfSAlain Knaffconfig KERNEL_LZMA
36930d65dbfSAlain Knaff	bool "LZMA"
3702e9f3bddSH. Peter Anvin	depends on HAVE_KERNEL_LZMA
37130d65dbfSAlain Knaff	help
3720a4dd35cSRandy Dunlap	  This compression algorithm's ratio is best.  Decompression speed
3730a4dd35cSRandy Dunlap	  is between gzip and bzip2.  Compression is slowest.
3740a4dd35cSRandy Dunlap	  The kernel size is about 33% smaller with LZMA in comparison to gzip.
37530d65dbfSAlain Knaff
3763ebe1243SLasse Collinconfig KERNEL_XZ
3773ebe1243SLasse Collin	bool "XZ"
3783ebe1243SLasse Collin	depends on HAVE_KERNEL_XZ
3793ebe1243SLasse Collin	help
3803ebe1243SLasse Collin	  XZ uses the LZMA2 algorithm and instruction set specific
3813ebe1243SLasse Collin	  BCJ filters which can improve compression ratio of executable
3823ebe1243SLasse Collin	  code. The size of the kernel is about 30% smaller with XZ in
3833ebe1243SLasse Collin	  comparison to gzip. On architectures for which there is a BCJ
3847472ff8aSLasse Collin	  filter (i386, x86_64, ARM, ARM64, RISC-V, big endian PowerPC,
3857472ff8aSLasse Collin	  and SPARC), XZ will create a few percent smaller kernel than
3867472ff8aSLasse Collin	  plain LZMA.
3873ebe1243SLasse Collin
3883ebe1243SLasse Collin	  The speed is about the same as with LZMA: The decompression
3893ebe1243SLasse Collin	  speed of XZ is better than that of bzip2 but worse than gzip
3903ebe1243SLasse Collin	  and LZO. Compression is slow.
3913ebe1243SLasse Collin
3927dd65febSAlbin Tonnerreconfig KERNEL_LZO
3937dd65febSAlbin Tonnerre	bool "LZO"
3947dd65febSAlbin Tonnerre	depends on HAVE_KERNEL_LZO
3957dd65febSAlbin Tonnerre	help
3960a4dd35cSRandy Dunlap	  Its compression ratio is the poorest among the choices. The kernel
397681b3049SStephan Sperber	  size is about 10% bigger than gzip; however its speed
3987dd65febSAlbin Tonnerre	  (both compression and decompression) is the fastest.
3997dd65febSAlbin Tonnerre
400e76e1fdfSKyungsik Leeconfig KERNEL_LZ4
401e76e1fdfSKyungsik Lee	bool "LZ4"
402e76e1fdfSKyungsik Lee	depends on HAVE_KERNEL_LZ4
403e76e1fdfSKyungsik Lee	help
404e76e1fdfSKyungsik Lee	  LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
405e76e1fdfSKyungsik Lee	  A preliminary version of LZ4 de/compression tool is available at
406e76e1fdfSKyungsik Lee	  <https://code.google.com/p/lz4/>.
407e76e1fdfSKyungsik Lee
408e76e1fdfSKyungsik Lee	  Its compression ratio is worse than LZO. The size of the kernel
409e76e1fdfSKyungsik Lee	  is about 8% bigger than LZO. But the decompression speed is
410e76e1fdfSKyungsik Lee	  faster than LZO.
411e76e1fdfSKyungsik Lee
41248f7ddf7SNick Terrellconfig KERNEL_ZSTD
41348f7ddf7SNick Terrell	bool "ZSTD"
41448f7ddf7SNick Terrell	depends on HAVE_KERNEL_ZSTD
41548f7ddf7SNick Terrell	help
41648f7ddf7SNick Terrell	  ZSTD is a compression algorithm targeting intermediate compression
41748f7ddf7SNick Terrell	  with fast decompression speed. It will compress better than GZIP and
41848f7ddf7SNick Terrell	  decompress around the same speed as LZO, but slower than LZ4. You
41948f7ddf7SNick Terrell	  will need at least 192 KB RAM or more for booting. The zstd command
42048f7ddf7SNick Terrell	  line tool is required for compression.
42148f7ddf7SNick Terrell
422f16466afSVasily Gorbikconfig KERNEL_UNCOMPRESSED
423f16466afSVasily Gorbik	bool "None"
424f16466afSVasily Gorbik	depends on HAVE_KERNEL_UNCOMPRESSED
425f16466afSVasily Gorbik	help
426f16466afSVasily Gorbik	  Produce uncompressed kernel image. This option is usually not what
427f16466afSVasily Gorbik	  you want. It is useful for debugging the kernel in slow simulation
428f16466afSVasily Gorbik	  environments, where decompressing and moving the kernel is awfully
429f16466afSVasily Gorbik	  slow. This option allows early boot code to skip the decompressor
430f16466afSVasily Gorbik	  and jump right at uncompressed kernel image.
431f16466afSVasily Gorbik
43230d65dbfSAlain Knaffendchoice
43330d65dbfSAlain Knaff
434ada4ab7aSChris Downconfig DEFAULT_INIT
435ada4ab7aSChris Down	string "Default init path"
436ada4ab7aSChris Down	default ""
437ada4ab7aSChris Down	help
438ada4ab7aSChris Down	  This option determines the default init for the system if no init=
439ada4ab7aSChris Down	  option is passed on the kernel command line. If the requested path is
440ada4ab7aSChris Down	  not present, we will still then move on to attempting further
441ada4ab7aSChris Down	  locations (e.g. /sbin/init, etc). If this is empty, we will just use
442ada4ab7aSChris Down	  the fallback list when init= is not passed.
443ada4ab7aSChris Down
444bd5dc17bSJosh Triplettconfig DEFAULT_HOSTNAME
445bd5dc17bSJosh Triplett	string "Default hostname"
446bd5dc17bSJosh Triplett	default "(none)"
447bd5dc17bSJosh Triplett	help
448bd5dc17bSJosh Triplett	  This option determines the default system hostname before userspace
449bd5dc17bSJosh Triplett	  calls sethostname(2). The kernel traditionally uses "(none)" here,
450bd5dc17bSJosh Triplett	  but you may wish to use a different default here to make a minimal
451bd5dc17bSJosh Triplett	  system more usable with less configuration.
452bd5dc17bSJosh Triplett
4531da177e4SLinus Torvaldsconfig SYSVIPC
4541da177e4SLinus Torvalds	bool "System V IPC"
455a7f7f624SMasahiro Yamada	help
4561da177e4SLinus Torvalds	  Inter Process Communication is a suite of library functions and
4571da177e4SLinus Torvalds	  system calls which let processes (running programs) synchronize and
4581da177e4SLinus Torvalds	  exchange information. It is generally considered to be a good thing,
4591da177e4SLinus Torvalds	  and some programs won't run unless you say Y here. In particular, if
4601da177e4SLinus Torvalds	  you want to run the DOS emulator dosemu under Linux (read the
4611da177e4SLinus Torvalds	  DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
4621da177e4SLinus Torvalds	  you'll need to say Y here.
4631da177e4SLinus Torvalds
4641da177e4SLinus Torvalds	  You can find documentation about IPC with "info ipc" and also in
4651da177e4SLinus Torvalds	  section 6.4 of the Linux Programmer's Guide, available from
4661da177e4SLinus Torvalds	  <http://www.tldp.org/guides.html>.
4671da177e4SLinus Torvalds
468a5494dcdSEric W. Biedermanconfig SYSVIPC_SYSCTL
469a5494dcdSEric W. Biederman	bool
470a5494dcdSEric W. Biederman	depends on SYSVIPC
471a5494dcdSEric W. Biederman	depends on SYSCTL
472a5494dcdSEric W. Biederman	default y
473a5494dcdSEric W. Biederman
4740cbed0eeSGuo Renconfig SYSVIPC_COMPAT
4750cbed0eeSGuo Ren	def_bool y
4760cbed0eeSGuo Ren	depends on COMPAT && SYSVIPC
4770cbed0eeSGuo Ren
4781da177e4SLinus Torvaldsconfig POSIX_MQUEUE
4791da177e4SLinus Torvalds	bool "POSIX Message Queues"
48019c92399SKees Cook	depends on NET
481a7f7f624SMasahiro Yamada	help
4821da177e4SLinus Torvalds	  POSIX variant of message queues is a part of IPC. In POSIX message
4831da177e4SLinus Torvalds	  queues every message has a priority which decides about succession
4841da177e4SLinus Torvalds	  of receiving it by a process. If you want to compile and run
4851da177e4SLinus Torvalds	  programs written e.g. for Solaris with use of its POSIX message
486b0e37650SRobert P. J. Day	  queues (functions mq_*) say Y here.
4871da177e4SLinus Torvalds
4881da177e4SLinus Torvalds	  POSIX message queues are visible as a filesystem called 'mqueue'
4891da177e4SLinus Torvalds	  and can be mounted somewhere if you want to do filesystem
4901da177e4SLinus Torvalds	  operations on message queues.
4911da177e4SLinus Torvalds
4921da177e4SLinus Torvalds	  If unsure, say Y.
4931da177e4SLinus Torvalds
494bdc8e5f8SSerge E. Hallynconfig POSIX_MQUEUE_SYSCTL
495bdc8e5f8SSerge E. Hallyn	bool
496bdc8e5f8SSerge E. Hallyn	depends on POSIX_MQUEUE
497bdc8e5f8SSerge E. Hallyn	depends on SYSCTL
498bdc8e5f8SSerge E. Hallyn	default y
499bdc8e5f8SSerge E. Hallyn
500c73be61cSDavid Howellsconfig WATCH_QUEUE
501c73be61cSDavid Howells	bool "General notification queue"
502c73be61cSDavid Howells	default n
503c73be61cSDavid Howells	help
504c73be61cSDavid Howells
505c73be61cSDavid Howells	  This is a general notification queue for the kernel to pass events to
506c73be61cSDavid Howells	  userspace by splicing them into pipes.  It can be used in conjunction
507c73be61cSDavid Howells	  with watches for key/keyring change notifications and device
508c73be61cSDavid Howells	  notifications.
509c73be61cSDavid Howells
510c02b872aSMauro Carvalho Chehab	  See Documentation/core-api/watch_queue.rst
511c73be61cSDavid Howells
512226b4ccdSKonstantin Khlebnikovconfig CROSS_MEMORY_ATTACH
513226b4ccdSKonstantin Khlebnikov	bool "Enable process_vm_readv/writev syscalls"
514226b4ccdSKonstantin Khlebnikov	depends on MMU
515226b4ccdSKonstantin Khlebnikov	default y
516226b4ccdSKonstantin Khlebnikov	help
517226b4ccdSKonstantin Khlebnikov	  Enabling this option adds the system calls process_vm_readv and
518226b4ccdSKonstantin Khlebnikov	  process_vm_writev which allow a process with the correct privileges
519a2a368d9SGeert Uytterhoeven	  to directly read from or write to another process' address space.
520226b4ccdSKonstantin Khlebnikov	  See the man page for more details.
521226b4ccdSKonstantin Khlebnikov
5221da177e4SLinus Torvaldsconfig AUDIT
5231da177e4SLinus Torvalds	bool "Auditing support"
524804a6a49SChris Wright	depends on NET
5251da177e4SLinus Torvalds	help
5261da177e4SLinus Torvalds	  Enable auditing infrastructure that can be used with another
5271da177e4SLinus Torvalds	  kernel subsystem, such as SELinux (which requires this for
528cb74ed27SPaul Moore	  logging of avc messages output).  System call auditing is included
529cb74ed27SPaul Moore	  on architectures which support it.
5301da177e4SLinus Torvalds
5317a017721SAKASHI Takahiroconfig HAVE_ARCH_AUDITSYSCALL
5327a017721SAKASHI Takahiro	bool
5337a017721SAKASHI Takahiro
5341da177e4SLinus Torvaldsconfig AUDITSYSCALL
535cb74ed27SPaul Moore	def_bool y
5367a017721SAKASHI Takahiro	depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
53728a3a7ebSEric Paris	select FSNOTIFY
53874c3cbe3SAl Viro
539d9817ebeSThomas Gleixnersource "kernel/irq/Kconfig"
540764e0da1SThomas Gleixnersource "kernel/time/Kconfig"
541b24abcffSDaniel Borkmannsource "kernel/bpf/Kconfig"
54287a4c375SChristoph Hellwigsource "kernel/Kconfig.preempt"
543d9817ebeSThomas Gleixner
544391dc69cSFrederic Weisbeckermenu "CPU/Task time and stats accounting"
545391dc69cSFrederic Weisbecker
546abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING
547abf917cdSFrederic Weisbecker	bool
548abf917cdSFrederic Weisbecker
549fdf9c356SFrederic Weisbeckerchoice
550fdf9c356SFrederic Weisbecker	prompt "Cputime accounting"
55102382affSNicholas Piggin	default TICK_CPU_ACCOUNTING
552fdf9c356SFrederic Weisbecker
553fdf9c356SFrederic Weisbecker# Kind of a stub config for the pure tick based cputime accounting
554fdf9c356SFrederic Weisbeckerconfig TICK_CPU_ACCOUNTING
555fdf9c356SFrederic Weisbecker	bool "Simple tick based cputime accounting"
556c58b0df1SFrederic Weisbecker	depends on !S390 && !NO_HZ_FULL
557fdf9c356SFrederic Weisbecker	help
558fdf9c356SFrederic Weisbecker	  This is the basic tick based cputime accounting that maintains
559fdf9c356SFrederic Weisbecker	  statistics about user, system and idle time spent on per jiffies
560fdf9c356SFrederic Weisbecker	  granularity.
561fdf9c356SFrederic Weisbecker
562fdf9c356SFrederic Weisbecker	  If unsure, say Y.
563fdf9c356SFrederic Weisbecker
564abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING_NATIVE
565391dc69cSFrederic Weisbecker	bool "Deterministic task and CPU time accounting"
566c58b0df1SFrederic Weisbecker	depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
567abf917cdSFrederic Weisbecker	select VIRT_CPU_ACCOUNTING
568391dc69cSFrederic Weisbecker	help
569391dc69cSFrederic Weisbecker	  Select this option to enable more accurate task and CPU time
570391dc69cSFrederic Weisbecker	  accounting.  This is done by reading a CPU counter on each
571391dc69cSFrederic Weisbecker	  kernel entry and exit and on transitions within the kernel
572391dc69cSFrederic Weisbecker	  between system, softirq and hardirq state, so there is a
573391dc69cSFrederic Weisbecker	  small performance impact.  In the case of s390 or IBM POWER > 5,
574391dc69cSFrederic Weisbecker	  this also enables accounting of stolen time on logically-partitioned
575391dc69cSFrederic Weisbecker	  systems.
576391dc69cSFrederic Weisbecker
577abf917cdSFrederic Weisbeckerconfig VIRT_CPU_ACCOUNTING_GEN
578abf917cdSFrederic Weisbecker	bool "Full dynticks CPU time accounting"
57924a9c541SFrederic Weisbecker	depends on HAVE_CONTEXT_TRACKING_USER
580554b0004SKevin Hilman	depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
581041a1574SArnd Bergmann	depends on GENERIC_CLOCKEVENTS
582abf917cdSFrederic Weisbecker	select VIRT_CPU_ACCOUNTING
58324a9c541SFrederic Weisbecker	select CONTEXT_TRACKING_USER
584abf917cdSFrederic Weisbecker	help
585abf917cdSFrederic Weisbecker	  Select this option to enable task and CPU time accounting on full
586abf917cdSFrederic Weisbecker	  dynticks systems. This accounting is implemented by watching every
587abf917cdSFrederic Weisbecker	  kernel-user boundaries using the context tracking subsystem.
588abf917cdSFrederic Weisbecker	  The accounting is thus performed at the expense of some significant
589abf917cdSFrederic Weisbecker	  overhead.
590abf917cdSFrederic Weisbecker
591abf917cdSFrederic Weisbecker	  For now this is only useful if you are working on the full
592abf917cdSFrederic Weisbecker	  dynticks subsystem development.
593abf917cdSFrederic Weisbecker
594abf917cdSFrederic Weisbecker	  If unsure, say N.
595abf917cdSFrederic Weisbecker
596b58c3584SRik van Rielendchoice
597b58c3584SRik van Riel
598fdf9c356SFrederic Weisbeckerconfig IRQ_TIME_ACCOUNTING
599fdf9c356SFrederic Weisbecker	bool "Fine granularity task level IRQ time accounting"
600b58c3584SRik van Riel	depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
601fdf9c356SFrederic Weisbecker	help
602fdf9c356SFrederic Weisbecker	  Select this option to enable fine granularity task irq time
603fdf9c356SFrederic Weisbecker	  accounting. This is done by reading a timestamp on each
604fdf9c356SFrederic Weisbecker	  transitions between softirq and hardirq state, so there can be a
605fdf9c356SFrederic Weisbecker	  small performance impact.
606fdf9c356SFrederic Weisbecker
607fdf9c356SFrederic Weisbecker	  If in doubt, say N here.
608fdf9c356SFrederic Weisbecker
60911d4afd4SVincent Guittotconfig HAVE_SCHED_AVG_IRQ
61011d4afd4SVincent Guittot	def_bool y
61111d4afd4SVincent Guittot	depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING
61211d4afd4SVincent Guittot	depends on SMP
61311d4afd4SVincent Guittot
614d4dbc991SVincent Guittotconfig SCHED_HW_PRESSURE
61598eb401dSValentin Schneider	bool
616fcd7c9c3SValentin Schneider	default y if ARM && ARM_CPU_TOPOLOGY
617fcd7c9c3SValentin Schneider	default y if ARM64
61876504793SThara Gopinath	depends on SMP
61998eb401dSValentin Schneider	depends on CPU_FREQ_THERMAL
62098eb401dSValentin Schneider	help
621d4dbc991SVincent Guittot	  Select this option to enable HW pressure accounting in the
622d4dbc991SVincent Guittot	  scheduler. HW pressure is the value conveyed to the scheduler
62398eb401dSValentin Schneider	  that reflects the reduction in CPU compute capacity resulted from
624d4dbc991SVincent Guittot	  HW throttling. HW throttling occurs when the performance of
625d4dbc991SVincent Guittot	  a CPU is capped due to high operating temperatures as an example.
62698eb401dSValentin Schneider
62798eb401dSValentin Schneider	  If selected, the scheduler will be able to balance tasks accordingly,
62898eb401dSValentin Schneider	  i.e. put less load on throttled CPUs than on non/less throttled ones.
62998eb401dSValentin Schneider
63098eb401dSValentin Schneider	  This requires the architecture to implement
631d4dbc991SVincent Guittot	  arch_update_hw_pressure() and arch_scale_thermal_pressure().
63276504793SThara Gopinath
633391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT
63446329a9dSJeff Layton	bool "BSD Process Accounting (DEPRECATED)"
6352813893fSIulia Manda	depends on MULTIUSER
63646329a9dSJeff Layton	default n
637391dc69cSFrederic Weisbecker	help
638391dc69cSFrederic Weisbecker	  If you say Y here, a user level program will be able to instruct the
639391dc69cSFrederic Weisbecker	  kernel (via a special system call) to write process accounting
640391dc69cSFrederic Weisbecker	  information to a file: whenever a process exits, information about
641391dc69cSFrederic Weisbecker	  that process will be appended to the file by the kernel.  The
642391dc69cSFrederic Weisbecker	  information includes things such as creation time, owning user,
643391dc69cSFrederic Weisbecker	  command name, memory usage, controlling terminal etc. (the complete
644391dc69cSFrederic Weisbecker	  list is in the struct acct in <file:include/linux/acct.h>).  It is
645391dc69cSFrederic Weisbecker	  up to the user level program to do useful things with this
64646329a9dSJeff Layton	  information.  This mechanism is antiquated and has significant
64746329a9dSJeff Layton	  scalability issues.  You probably want to use eBPF instead.  Say
64846329a9dSJeff Layton	  N unless you really need this.
649391dc69cSFrederic Weisbecker
650391dc69cSFrederic Weisbeckerconfig BSD_PROCESS_ACCT_V3
651391dc69cSFrederic Weisbecker	bool "BSD Process Accounting version 3 file format"
652391dc69cSFrederic Weisbecker	depends on BSD_PROCESS_ACCT
653391dc69cSFrederic Weisbecker	default n
654391dc69cSFrederic Weisbecker	help
655391dc69cSFrederic Weisbecker	  If you say Y here, the process accounting information is written
656391dc69cSFrederic Weisbecker	  in a new file format that also logs the process IDs of each
6573903bf94SRandy Dunlap	  process and its parent. Note that this file format is incompatible
658391dc69cSFrederic Weisbecker	  with previous v0/v1/v2 file formats, so you will need updated tools
659391dc69cSFrederic Weisbecker	  for processing it. A preliminary version of these tools is available
660391dc69cSFrederic Weisbecker	  at <http://www.gnu.org/software/acct/>.
661391dc69cSFrederic Weisbecker
662391dc69cSFrederic Weisbeckerconfig TASKSTATS
66319c92399SKees Cook	bool "Export task/process statistics through netlink"
664391dc69cSFrederic Weisbecker	depends on NET
6652813893fSIulia Manda	depends on MULTIUSER
666391dc69cSFrederic Weisbecker	default n
667391dc69cSFrederic Weisbecker	help
668391dc69cSFrederic Weisbecker	  Export selected statistics for tasks/processes through the
669391dc69cSFrederic Weisbecker	  generic netlink interface. Unlike BSD process accounting, the
670391dc69cSFrederic Weisbecker	  statistics are available during the lifetime of tasks/processes as
671391dc69cSFrederic Weisbecker	  responses to commands. Like BSD accounting, they are sent to user
672391dc69cSFrederic Weisbecker	  space on task exit.
673391dc69cSFrederic Weisbecker
674391dc69cSFrederic Weisbecker	  Say N if unsure.
675391dc69cSFrederic Weisbecker
676391dc69cSFrederic Weisbeckerconfig TASK_DELAY_ACCT
67719c92399SKees Cook	bool "Enable per-task delay accounting"
678391dc69cSFrederic Weisbecker	depends on TASKSTATS
679f6db8347SNaveen N. Rao	select SCHED_INFO
680391dc69cSFrederic Weisbecker	help
681391dc69cSFrederic Weisbecker	  Collect information on time spent by a task waiting for system
682391dc69cSFrederic Weisbecker	  resources like cpu, synchronous block I/O completion and swapping
683391dc69cSFrederic Weisbecker	  in pages. Such statistics can help in setting a task's priorities
684391dc69cSFrederic Weisbecker	  relative to other tasks for cpu, io, rss limits etc.
685391dc69cSFrederic Weisbecker
686391dc69cSFrederic Weisbecker	  Say N if unsure.
687391dc69cSFrederic Weisbecker
688391dc69cSFrederic Weisbeckerconfig TASK_XACCT
68919c92399SKees Cook	bool "Enable extended accounting over taskstats"
690391dc69cSFrederic Weisbecker	depends on TASKSTATS
691391dc69cSFrederic Weisbecker	help
692391dc69cSFrederic Weisbecker	  Collect extended task accounting data and send the data
693391dc69cSFrederic Weisbecker	  to userland for processing over the taskstats interface.
694391dc69cSFrederic Weisbecker
695391dc69cSFrederic Weisbecker	  Say N if unsure.
696391dc69cSFrederic Weisbecker
697391dc69cSFrederic Weisbeckerconfig TASK_IO_ACCOUNTING
69819c92399SKees Cook	bool "Enable per-task storage I/O accounting"
699391dc69cSFrederic Weisbecker	depends on TASK_XACCT
700391dc69cSFrederic Weisbecker	help
701391dc69cSFrederic Weisbecker	  Collect information on the number of bytes of storage I/O which this
702391dc69cSFrederic Weisbecker	  task has caused.
703391dc69cSFrederic Weisbecker
704391dc69cSFrederic Weisbecker	  Say N if unsure.
705391dc69cSFrederic Weisbecker
706eb414681SJohannes Weinerconfig PSI
707eb414681SJohannes Weiner	bool "Pressure stall information tracking"
70898dfdd9eSRandy Dunlap	select KERNFS
709eb414681SJohannes Weiner	help
710eb414681SJohannes Weiner	  Collect metrics that indicate how overcommitted the CPU, memory,
711eb414681SJohannes Weiner	  and IO capacity are in the system.
712eb414681SJohannes Weiner
713eb414681SJohannes Weiner	  If you say Y here, the kernel will create /proc/pressure/ with the
714eb414681SJohannes Weiner	  pressure statistics files cpu, memory, and io. These will indicate
715eb414681SJohannes Weiner	  the share of walltime in which some or all tasks in the system are
716eb414681SJohannes Weiner	  delayed due to contention of the respective resource.
717eb414681SJohannes Weiner
7182ce7135aSJohannes Weiner	  In kernels with cgroup support, cgroups (cgroup2 only) will
7192ce7135aSJohannes Weiner	  have cpu.pressure, memory.pressure, and io.pressure files,
7202ce7135aSJohannes Weiner	  which aggregate pressure stalls for the grouped tasks only.
7212ce7135aSJohannes Weiner
722c3123552SMauro Carvalho Chehab	  For more details see Documentation/accounting/psi.rst.
723eb414681SJohannes Weiner
724eb414681SJohannes Weiner	  Say N if unsure.
725eb414681SJohannes Weiner
726e0c27447SJohannes Weinerconfig PSI_DEFAULT_DISABLED
727e0c27447SJohannes Weiner	bool "Require boot parameter to enable pressure stall information tracking"
728e0c27447SJohannes Weiner	default n
729e0c27447SJohannes Weiner	depends on PSI
730e0c27447SJohannes Weiner	help
731e0c27447SJohannes Weiner	  If set, pressure stall information tracking will be disabled
732428a1cb4SBaruch Siach	  per default but can be enabled through passing psi=1 on the
733428a1cb4SBaruch Siach	  kernel commandline during boot.
734e0c27447SJohannes Weiner
7357b2489d3SJohannes Weiner	  This feature adds some code to the task wakeup and sleep
7367b2489d3SJohannes Weiner	  paths of the scheduler. The overhead is too low to affect
7377b2489d3SJohannes Weiner	  common scheduling-intense workloads in practice (such as
7387b2489d3SJohannes Weiner	  webservers, memcache), but it does show up in artificial
7397b2489d3SJohannes Weiner	  scheduler stress tests, such as hackbench.
7407b2489d3SJohannes Weiner
7417b2489d3SJohannes Weiner	  If you are paranoid and not sure what the kernel will be
7427b2489d3SJohannes Weiner	  used for, say Y.
7437b2489d3SJohannes Weiner
7447b2489d3SJohannes Weiner	  Say N if unsure.
7457b2489d3SJohannes Weiner
746391dc69cSFrederic Weisbeckerendmenu # "CPU/Task time and stats accounting"
747391dc69cSFrederic Weisbecker
7485c4991e2SFrederic Weisbeckerconfig CPU_ISOLATION
7495c4991e2SFrederic Weisbecker	bool "CPU isolation"
75097577684SOleg Nesterov	depends on SMP
7512c43838cSFrederic Weisbecker	default y
7525c4991e2SFrederic Weisbecker	help
7535c4991e2SFrederic Weisbecker	  Make sure that CPUs running critical tasks are not disturbed by
7545c4991e2SFrederic Weisbecker	  any source of "noise" such as unbound workqueues, timers, kthreads...
7552c43838cSFrederic Weisbecker	  Unbound jobs get offloaded to housekeeping CPUs. This is driven by
7562c43838cSFrederic Weisbecker	  the "isolcpus=" boot parameter.
7572c43838cSFrederic Weisbecker
7582c43838cSFrederic Weisbecker	  Say Y if unsure.
7595c4991e2SFrederic Weisbecker
7600af92d46SPaul E. McKenneysource "kernel/rcu/Kconfig"
761c903ff83SMike Travis
7621da177e4SLinus Torvaldsconfig IKCONFIG
763f2443ab6SRoss Biro	tristate "Kernel .config support"
764a7f7f624SMasahiro Yamada	help
7651da177e4SLinus Torvalds	  This option enables the complete Linux kernel ".config" file
7661da177e4SLinus Torvalds	  contents to be saved in the kernel. It provides documentation
7671da177e4SLinus Torvalds	  of which kernel options are used in a running kernel or in an
7681da177e4SLinus Torvalds	  on-disk kernel.  This information can be extracted from the kernel
7691da177e4SLinus Torvalds	  image file with the script scripts/extract-ikconfig and used as
7701da177e4SLinus Torvalds	  input to rebuild the current kernel or to build another kernel.
7711da177e4SLinus Torvalds	  It can also be extracted from a running kernel by reading
7721da177e4SLinus Torvalds	  /proc/config.gz if enabled (below).
7731da177e4SLinus Torvalds
7741da177e4SLinus Torvaldsconfig IKCONFIG_PROC
7751da177e4SLinus Torvalds	bool "Enable access to .config through /proc/config.gz"
7761da177e4SLinus Torvalds	depends on IKCONFIG && PROC_FS
777a7f7f624SMasahiro Yamada	help
7781da177e4SLinus Torvalds	  This option enables access to the kernel configuration file
7791da177e4SLinus Torvalds	  through /proc/config.gz.
7801da177e4SLinus Torvalds
781f7b101d3SJoel Fernandes (Google)config IKHEADERS
782f7b101d3SJoel Fernandes (Google)	tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz"
783f7b101d3SJoel Fernandes (Google)	depends on SYSFS
78443d8ce9dSJoel Fernandes (Google)	help
785f7b101d3SJoel Fernandes (Google)	  This option enables access to the in-kernel headers that are generated during
786f7b101d3SJoel Fernandes (Google)	  the build process. These can be used to build eBPF tracing programs,
787f7b101d3SJoel Fernandes (Google)	  or similar programs.  If you build the headers as a module, a module called
788f7b101d3SJoel Fernandes (Google)	  kheaders.ko is built which can be loaded on-demand to get access to headers.
78943d8ce9dSJoel Fernandes (Google)
790794543a2SAlistair John Strachanconfig LOG_BUF_SHIFT
791794543a2SAlistair John Strachan	int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
7921c4b5ecbSChristoph Hellwig	range 12 25
793f17a32e9SAdrian Bunk	default 17
794361e9dfbSJosh Triplett	depends on PRINTK
795794543a2SAlistair John Strachan	help
79623b2899fSLuis R. Rodriguez	  Select the minimal kernel log buffer size as a power of 2.
79723b2899fSLuis R. Rodriguez	  The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
79823b2899fSLuis R. Rodriguez	  parameter, see below. Any higher size also might be forced
79923b2899fSLuis R. Rodriguez	  by "log_buf_len" boot parameter.
80023b2899fSLuis R. Rodriguez
801f17a32e9SAdrian Bunk	  Examples:
802f17a32e9SAdrian Bunk		     17 => 128 KB
803f17a32e9SAdrian Bunk		     16 => 64 KB
804f17a32e9SAdrian Bunk		     15 => 32 KB
805f17a32e9SAdrian Bunk		     14 => 16 KB
806794543a2SAlistair John Strachan		     13 =>  8 KB
807794543a2SAlistair John Strachan		     12 =>  4 KB
808794543a2SAlistair John Strachan
80923b2899fSLuis R. Rodriguezconfig LOG_CPU_MAX_BUF_SHIFT
81023b2899fSLuis R. Rodriguez	int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
8112240a31dSGeert Uytterhoeven	depends on SMP
81223b2899fSLuis R. Rodriguez	range 0 21
81323b2899fSLuis R. Rodriguez	default 0 if BASE_SMALL
814320bf431SYoann Congal	default 12
815361e9dfbSJosh Triplett	depends on PRINTK
81623b2899fSLuis R. Rodriguez	help
81723b2899fSLuis R. Rodriguez	  This option allows to increase the default ring buffer size
81823b2899fSLuis R. Rodriguez	  according to the number of CPUs. The value defines the contribution
81923b2899fSLuis R. Rodriguez	  of each CPU as a power of 2. The used space is typically only few
82023b2899fSLuis R. Rodriguez	  lines however it might be much more when problems are reported,
82123b2899fSLuis R. Rodriguez	  e.g. backtraces.
82223b2899fSLuis R. Rodriguez
82323b2899fSLuis R. Rodriguez	  The increased size means that a new buffer has to be allocated and
82423b2899fSLuis R. Rodriguez	  the original static one is unused. It makes sense only on systems
82523b2899fSLuis R. Rodriguez	  with more CPUs. Therefore this value is used only when the sum of
82623b2899fSLuis R. Rodriguez	  contributions is greater than the half of the default kernel ring
82723b2899fSLuis R. Rodriguez	  buffer as defined by LOG_BUF_SHIFT. The default values are set
8280f7636e1SPaul Menzel	  so that more than 16 CPUs are needed to trigger the allocation.
82923b2899fSLuis R. Rodriguez
83023b2899fSLuis R. Rodriguez	  Also this option is ignored when "log_buf_len" kernel parameter is
83123b2899fSLuis R. Rodriguez	  used as it forces an exact (power of two) size of the ring buffer.
83223b2899fSLuis R. Rodriguez
83323b2899fSLuis R. Rodriguez	  The number of possible CPUs is used for this computation ignoring
8345e0d8d59SGeert Uytterhoeven	  hotplugging making the computation optimal for the worst case
8355e0d8d59SGeert Uytterhoeven	  scenario while allowing a simple algorithm to be used from bootup.
83623b2899fSLuis R. Rodriguez
83723b2899fSLuis R. Rodriguez	  Examples shift values and their meaning:
83823b2899fSLuis R. Rodriguez		     17 => 128 KB for each CPU
83923b2899fSLuis R. Rodriguez		     16 =>  64 KB for each CPU
84023b2899fSLuis R. Rodriguez		     15 =>  32 KB for each CPU
84123b2899fSLuis R. Rodriguez		     14 =>  16 KB for each CPU
84223b2899fSLuis R. Rodriguez		     13 =>   8 KB for each CPU
84323b2899fSLuis R. Rodriguez		     12 =>   4 KB for each CPU
84423b2899fSLuis R. Rodriguez
84533701557SChris Downconfig PRINTK_INDEX
84633701557SChris Down	bool "Printk indexing debugfs interface"
84733701557SChris Down	depends on PRINTK && DEBUG_FS
84833701557SChris Down	help
84933701557SChris Down	  Add support for indexing of all printk formats known at compile time
85033701557SChris Down	  at <debugfs>/printk/index/<module>.
85133701557SChris Down
85233701557SChris Down	  This can be used as part of maintaining daemons which monitor
85333701557SChris Down	  /dev/kmsg, as it permits auditing the printk formats present in a
85433701557SChris Down	  kernel, allowing detection of cases where monitored printks are
85533701557SChris Down	  changed or no longer present.
85633701557SChris Down
85733701557SChris Down	  There is no additional runtime cost to printk with this enabled.
85833701557SChris Down
8595cdc38f9SKAMEZAWA Hiroyuki#
8605cdc38f9SKAMEZAWA Hiroyuki# Architectures with an unreliable sched_clock() should select this:
8615cdc38f9SKAMEZAWA Hiroyuki#
8625cdc38f9SKAMEZAWA Hiroyukiconfig HAVE_UNSTABLE_SCHED_CLOCK
8635cdc38f9SKAMEZAWA Hiroyuki	bool
8645cdc38f9SKAMEZAWA Hiroyuki
86538ff87f7SStephen Boydconfig GENERIC_SCHED_CLOCK
86638ff87f7SStephen Boyd	bool
86738ff87f7SStephen Boyd
86869842cbaSPatrick Bellasimenu "Scheduler features"
86969842cbaSPatrick Bellasi
87069842cbaSPatrick Bellasiconfig UCLAMP_TASK
87169842cbaSPatrick Bellasi	bool "Enable utilization clamping for RT/FAIR tasks"
87269842cbaSPatrick Bellasi	depends on CPU_FREQ_GOV_SCHEDUTIL
87369842cbaSPatrick Bellasi	help
87469842cbaSPatrick Bellasi	  This feature enables the scheduler to track the clamped utilization
87569842cbaSPatrick Bellasi	  of each CPU based on RUNNABLE tasks scheduled on that CPU.
87669842cbaSPatrick Bellasi
87769842cbaSPatrick Bellasi	  With this option, the user can specify the min and max CPU
87869842cbaSPatrick Bellasi	  utilization allowed for RUNNABLE tasks. The max utilization defines
87969842cbaSPatrick Bellasi	  the maximum frequency a task should use while the min utilization
88069842cbaSPatrick Bellasi	  defines the minimum frequency it should use.
88169842cbaSPatrick Bellasi
88269842cbaSPatrick Bellasi	  Both min and max utilization clamp values are hints to the scheduler,
88369842cbaSPatrick Bellasi	  aiming at improving its frequency selection policy, but they do not
88469842cbaSPatrick Bellasi	  enforce or grant any specific bandwidth for tasks.
88569842cbaSPatrick Bellasi
88669842cbaSPatrick Bellasi	  If in doubt, say N.
88769842cbaSPatrick Bellasi
88869842cbaSPatrick Bellasiconfig UCLAMP_BUCKETS_COUNT
88969842cbaSPatrick Bellasi	int "Number of supported utilization clamp buckets"
89069842cbaSPatrick Bellasi	range 5 20
89169842cbaSPatrick Bellasi	default 5
89269842cbaSPatrick Bellasi	depends on UCLAMP_TASK
89369842cbaSPatrick Bellasi	help
89469842cbaSPatrick Bellasi	  Defines the number of clamp buckets to use. The range of each bucket
89569842cbaSPatrick Bellasi	  will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the
89669842cbaSPatrick Bellasi	  number of clamp buckets the finer their granularity and the higher
89769842cbaSPatrick Bellasi	  the precision of clamping aggregation and tracking at run-time.
89869842cbaSPatrick Bellasi
89969842cbaSPatrick Bellasi	  For example, with the minimum configuration value we will have 5
90069842cbaSPatrick Bellasi	  clamp buckets tracking 20% utilization each. A 25% boosted tasks will
90169842cbaSPatrick Bellasi	  be refcounted in the [20..39]% bucket and will set the bucket clamp
90269842cbaSPatrick Bellasi	  effective value to 25%.
90369842cbaSPatrick Bellasi	  If a second 30% boosted task should be co-scheduled on the same CPU,
90469842cbaSPatrick Bellasi	  that task will be refcounted in the same bucket of the first task and
90569842cbaSPatrick Bellasi	  it will boost the bucket clamp effective value to 30%.
90669842cbaSPatrick Bellasi	  The clamp effective value of a bucket is reset to its nominal value
90769842cbaSPatrick Bellasi	  (20% in the example above) when there are no more tasks refcounted in
90869842cbaSPatrick Bellasi	  that bucket.
90969842cbaSPatrick Bellasi
91069842cbaSPatrick Bellasi	  An additional boost/capping margin can be added to some tasks. In the
91169842cbaSPatrick Bellasi	  example above the 25% task will be boosted to 30% until it exits the
91269842cbaSPatrick Bellasi	  CPU. If that should be considered not acceptable on certain systems,
91369842cbaSPatrick Bellasi	  it's always possible to reduce the margin by increasing the number of
91469842cbaSPatrick Bellasi	  clamp buckets to trade off used memory for run-time tracking
91569842cbaSPatrick Bellasi	  precision.
91669842cbaSPatrick Bellasi
91769842cbaSPatrick Bellasi	  If in doubt, use the default value.
91869842cbaSPatrick Bellasi
91925c411fcSJohn Stultzconfig SCHED_PROXY_EXEC
92025c411fcSJohn Stultz	bool "Proxy Execution"
92125c411fcSJohn Stultz	# Avoid some build failures w/ PREEMPT_RT until it can be fixed
92225c411fcSJohn Stultz	depends on !PREEMPT_RT
92325c411fcSJohn Stultz	# Need to investigate how to inform sched_ext of split contexts
92425c411fcSJohn Stultz	depends on !SCHED_CLASS_EXT
92525c411fcSJohn Stultz	# Not particularly useful until we get to multi-rq proxying
92625c411fcSJohn Stultz	depends on EXPERT
92725c411fcSJohn Stultz	help
92825c411fcSJohn Stultz	  This option enables proxy execution, a mechanism for mutex-owning
92925c411fcSJohn Stultz	  tasks to inherit the scheduling context of higher priority waiters.
93025c411fcSJohn Stultz
93169842cbaSPatrick Bellasiendmenu
93269842cbaSPatrick Bellasi
933be3a7284SAndrea Arcangeli#
934be3a7284SAndrea Arcangeli# For architectures that want to enable the support for NUMA-affine scheduler
935be3a7284SAndrea Arcangeli# balancing logic:
936be3a7284SAndrea Arcangeli#
937be3a7284SAndrea Arcangeliconfig ARCH_SUPPORTS_NUMA_BALANCING
938be3a7284SAndrea Arcangeli	bool
939be3a7284SAndrea Arcangeli
940be5e610cSPeter Zijlstra#
94172b252aeSMel Gorman# For architectures that prefer to flush all TLBs after a number of pages
94272b252aeSMel Gorman# are unmapped instead of sending one IPI per page to flush. The architecture
94372b252aeSMel Gorman# must provide guarantees on what happens if a clean TLB cache entry is
94472b252aeSMel Gorman# written after the unmap. Details are in mm/rmap.c near the check for
94572b252aeSMel Gorman# should_defer_flush. The architecture should also consider if the full flush
94672b252aeSMel Gorman# and the refill costs are offset by the savings of sending fewer IPIs.
94772b252aeSMel Gormanconfig ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
94872b252aeSMel Gorman	bool
94972b252aeSMel Gorman
950c12d3362SArd Biesheuvelconfig CC_HAS_INT128
9513a7c7331SMasahiro Yamada	def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT
952c12d3362SArd Biesheuvel
953dee2b702SGustavo A. R. Silvaconfig CC_IMPLICIT_FALLTHROUGH
954dee2b702SGustavo A. R. Silva	string
955158ea2d2SGustavo A. R. Silva	default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5)
956dee2b702SGustavo A. R. Silva	default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough)
957dee2b702SGustavo A. R. Silva
9583e00f580SKees Cook# Currently, disable gcc-10+ array-bounds globally.
9590da6e5fdSLinus Torvalds# It's still broken in gcc-13, so no upper bound yet.
9603e00f580SKees Cookconfig GCC10_NO_ARRAY_BOUNDS
9615a41237aSLinus Torvalds	def_bool y
9625a41237aSLinus Torvalds
963f0be87c4SLinus Torvaldsconfig CC_NO_ARRAY_BOUNDS
964f0be87c4SLinus Torvalds	bool
9658e5bd4eaSYury Norov	default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC10_NO_ARRAY_BOUNDS
966f0be87c4SLinus Torvalds
96702153319SLinus Torvalds# Currently, disable -Wstringop-overflow for GCC globally.
96802153319SLinus Torvaldsconfig GCC_NO_STRINGOP_OVERFLOW
969a5e0ace0SGustavo A. R. Silva	def_bool y
970a5e0ace0SGustavo A. R. Silva
971a5e0ace0SGustavo A. R. Silvaconfig CC_NO_STRINGOP_OVERFLOW
972a5e0ace0SGustavo A. R. Silva	bool
97302153319SLinus Torvalds	default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW
974a5e0ace0SGustavo A. R. Silva
975a5e0ace0SGustavo A. R. Silvaconfig CC_STRINGOP_OVERFLOW
976a5e0ace0SGustavo A. R. Silva	bool
977a5e0ace0SGustavo A. R. Silva	default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW
978a5e0ace0SGustavo A. R. Silva
97972b252aeSMel Gorman#
980be5e610cSPeter Zijlstra# For architectures that know their GCC __int128 support is sound
981be5e610cSPeter Zijlstra#
982be5e610cSPeter Zijlstraconfig ARCH_SUPPORTS_INT128
983be5e610cSPeter Zijlstra	bool
984be5e610cSPeter Zijlstra
985be3a7284SAndrea Arcangeli# For architectures that (ab)use NUMA to represent different memory regions
986be3a7284SAndrea Arcangeli# all cpu-local but of different latencies, such as SuperH.
987be3a7284SAndrea Arcangeli#
988be3a7284SAndrea Arcangeliconfig ARCH_WANT_NUMA_VARIABLE_LOCALITY
989be3a7284SAndrea Arcangeli	bool
990be3a7284SAndrea Arcangeli
991be3a7284SAndrea Arcangeliconfig NUMA_BALANCING
992be3a7284SAndrea Arcangeli	bool "Memory placement aware NUMA scheduler"
993be3a7284SAndrea Arcangeli	depends on ARCH_SUPPORTS_NUMA_BALANCING
994be3a7284SAndrea Arcangeli	depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
995554b0f3cSSebastian Andrzej Siewior	depends on SMP && NUMA && MIGRATION && !PREEMPT_RT
996be3a7284SAndrea Arcangeli	help
997be3a7284SAndrea Arcangeli	  This option adds support for automatic NUMA aware memory/task placement.
998be3a7284SAndrea Arcangeli	  The mechanism is quite primitive and is based on migrating memory when
9996d56a410SPaul Gortmaker	  it has references to the node the task is running on.
1000be3a7284SAndrea Arcangeli
1001be3a7284SAndrea Arcangeli	  This system will be inactive on UMA systems.
1002be3a7284SAndrea Arcangeli
10036f7c97e8SAneesh Kumar K.Vconfig NUMA_BALANCING_DEFAULT_ENABLED
10046f7c97e8SAneesh Kumar K.V	bool "Automatically enable NUMA aware memory/task placement"
10056f7c97e8SAneesh Kumar K.V	default y
10066f7c97e8SAneesh Kumar K.V	depends on NUMA_BALANCING
10076f7c97e8SAneesh Kumar K.V	help
10086f7c97e8SAneesh Kumar K.V	  If set, automatic NUMA balancing will be enabled if running on a NUMA
10096f7c97e8SAneesh Kumar K.V	  machine.
10106f7c97e8SAneesh Kumar K.V
101121c690a3SSuren Baghdasaryanconfig SLAB_OBJ_EXT
101221c690a3SSuren Baghdasaryan	bool
101321c690a3SSuren Baghdasaryan
101423964d2dSLi Zefanmenuconfig CGROUPS
10156341e62bSChristoph Jaeger	bool "Control Group support"
10162bd59d48STejun Heo	select KERNFS
1017ddbcc7e8SPaul Menage	help
101823964d2dSLi Zefan	  This option adds support for grouping sets of processes together, for
10195cdc38f9SKAMEZAWA Hiroyuki	  use with process control subsystems such as Cpusets, CFS, memory
10205cdc38f9SKAMEZAWA Hiroyuki	  controls or device isolation.
10215cdc38f9SKAMEZAWA Hiroyuki	  See
1022d6a3b247SMauro Carvalho Chehab		- Documentation/scheduler/sched-design-CFS.rst	(CFS)
1023da82c92fSMauro Carvalho Chehab		- Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation
102445ce80fbSLi Zefan					  and resource control)
1025ddbcc7e8SPaul Menage
1026ddbcc7e8SPaul Menage	  Say N if unsure.
1027ddbcc7e8SPaul Menage
102823964d2dSLi Zefanif CGROUPS
102923964d2dSLi Zefan
10303e32cb2eSJohannes Weinerconfig PAGE_COUNTER
10313e32cb2eSJohannes Weiner	bool
10323e32cb2eSJohannes Weiner
10336a010a49STejun Heoconfig CGROUP_FAVOR_DYNMODS
10346a010a49STejun Heo        bool "Favor dynamic modification latency reduction by default"
10356a010a49STejun Heo        help
10366a010a49STejun Heo          This option enables the "favordynmods" mount option by default
10376a010a49STejun Heo          which reduces the latencies of dynamic cgroup modifications such
10386a010a49STejun Heo          as task migrations and controller on/offs at the cost of making
10396a010a49STejun Heo          hot path operations such as forks and exits more expensive.
10406a010a49STejun Heo
10416a010a49STejun Heo          Say N if unsure.
10426a010a49STejun Heo
1043c255a458SAndrew Mortonconfig MEMCG
1044a0166ec4SJohannes Weiner	bool "Memory controller"
10453e32cb2eSJohannes Weiner	select PAGE_COUNTER
104679bd9814STejun Heo	select EVENTFD
104721c690a3SSuren Baghdasaryan	select SLAB_OBJ_EXT
1048fdc5001bSKirill A. Shutemov	select VM_EVENT_COUNTERS
104900f0b825SBalbir Singh	help
1050a0166ec4SJohannes Weiner	  Provides control over the memory footprint of tasks in a cgroup.
105100f0b825SBalbir Singh
105225352d2fSShakeel Buttconfig MEMCG_NMI_UNSAFE
105325352d2fSShakeel Butt	bool
105425352d2fSShakeel Butt	depends on MEMCG
105525352d2fSShakeel Butt	depends on HAVE_NMI
105625352d2fSShakeel Butt	depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && !ARCH_HAVE_NMI_SAFE_CMPXCHG
105725352d2fSShakeel Butt	default y
105825352d2fSShakeel Butt
1059940b01fcSShakeel Buttconfig MEMCG_NMI_SAFETY_REQUIRES_ATOMIC
1060940b01fcSShakeel Butt	bool
1061940b01fcSShakeel Butt	depends on MEMCG
1062940b01fcSShakeel Butt	depends on HAVE_NMI
1063940b01fcSShakeel Butt	depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && ARCH_HAVE_NMI_SAFE_CMPXCHG
1064940b01fcSShakeel Butt	default y
1065940b01fcSShakeel Butt
1066e93d4166SRoman Gushchinconfig MEMCG_V1
1067e93d4166SRoman Gushchin	bool "Legacy cgroup v1 memory controller"
1068c9929f0eSVlastimil Babka	depends on MEMCG
1069e93d4166SRoman Gushchin	default n
1070e93d4166SRoman Gushchin	help
1071e93d4166SRoman Gushchin	  Legacy cgroup v1 memory controller which has been deprecated by
1072e93d4166SRoman Gushchin	  cgroup v2 implementation. The v1 is there for legacy applications
1073e93d4166SRoman Gushchin	  which haven't migrated to the new cgroup v2 interface yet. If you
1074e93d4166SRoman Gushchin	  do not have any such application then you are completely fine leaving
1075e93d4166SRoman Gushchin	  this option disabled.
1076e93d4166SRoman Gushchin
1077e93d4166SRoman Gushchin	  Please note that feature set of the legacy memory controller is likely
1078e93d4166SRoman Gushchin	  going to shrink due to deprecation process. New deployments with v1
1079e93d4166SRoman Gushchin	  controller are highly discouraged.
1080e93d4166SRoman Gushchin
1081fcb4824bSValdis Kletnieks	  Say N if unsure.
108284c07d11SKirill Tkhai
10836bf024e6SJohannes Weinerconfig BLK_CGROUP
10846bf024e6SJohannes Weiner	bool "IO controller"
10856bf024e6SJohannes Weiner	depends on BLOCK
10862bc64a20SAneesh Kumar K.V	default n
1087a7f7f624SMasahiro Yamada	help
10886bf024e6SJohannes Weiner	Generic block IO controller cgroup interface. This is the common
10896bf024e6SJohannes Weiner	cgroup interface which should be used by various IO controlling
10906bf024e6SJohannes Weiner	policies.
10912bc64a20SAneesh Kumar K.V
10926bf024e6SJohannes Weiner	Currently, CFQ IO scheduler uses it to recognize task groups and
10936bf024e6SJohannes Weiner	control disk bandwidth allocation (proportional time slice allocation)
10946bf024e6SJohannes Weiner	to such task groups. It is also used by bio throttling logic in
10956bf024e6SJohannes Weiner	block layer to implement upper limit in IO rates on a device.
1096e5d1367fSStephane Eranian
10976bf024e6SJohannes Weiner	This option only enables generic Block IO controller infrastructure.
10986bf024e6SJohannes Weiner	One needs to also enable actual IO controlling logic/policy. For
10996bf024e6SJohannes Weiner	enabling proportional weight division of disk bandwidth in CFQ, set
11007baf2199SKrzysztof Kozlowski	CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
11016bf024e6SJohannes Weiner	CONFIG_BLK_DEV_THROTTLING=y.
11026bf024e6SJohannes Weiner
1103da82c92fSMauro Carvalho Chehab	See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information.
11046bf024e6SJohannes Weiner
11056bf024e6SJohannes Weinerconfig CGROUP_WRITEBACK
11066bf024e6SJohannes Weiner	bool
11076bf024e6SJohannes Weiner	depends on MEMCG && BLK_CGROUP
11086bf024e6SJohannes Weiner	default y
1109e5d1367fSStephane Eranian
11107c941438SDhaval Gianimenuconfig CGROUP_SCHED
1111a0166ec4SJohannes Weiner	bool "CPU controller"
11127c941438SDhaval Giani	default n
11137c941438SDhaval Giani	help
11147c941438SDhaval Giani	  This feature lets CPU scheduler recognize task groups and control CPU
11157c941438SDhaval Giani	  bandwidth allocation to such task groups. It uses cgroups to group
11167c941438SDhaval Giani	  tasks.
11177c941438SDhaval Giani
11187c941438SDhaval Gianiif CGROUP_SCHED
1119e179e80cSTejun Heoconfig GROUP_SCHED_WEIGHT
1120e179e80cSTejun Heo	def_bool n
1121e179e80cSTejun Heo
1122ddceadceSTejun Heoconfig GROUP_SCHED_BANDWIDTH
1123ddceadceSTejun Heo        def_bool n
1124ddceadceSTejun Heo
11257c941438SDhaval Gianiconfig FAIR_GROUP_SCHED
11267c941438SDhaval Giani	bool "Group scheduling for SCHED_OTHER"
11277c941438SDhaval Giani	depends on CGROUP_SCHED
1128e179e80cSTejun Heo	select GROUP_SCHED_WEIGHT
11297c941438SDhaval Giani	default CGROUP_SCHED
11307c941438SDhaval Giani
1131ab84d31eSPaul Turnerconfig CFS_BANDWIDTH
1132ab84d31eSPaul Turner	bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1133ab84d31eSPaul Turner	depends on FAIR_GROUP_SCHED
1134ddceadceSTejun Heo	select GROUP_SCHED_BANDWIDTH
1135ab84d31eSPaul Turner	default n
1136ab84d31eSPaul Turner	help
1137ab84d31eSPaul Turner	  This option allows users to define CPU bandwidth rates (limits) for
1138ab84d31eSPaul Turner	  tasks running within the fair group scheduler.  Groups with no limit
1139ab84d31eSPaul Turner	  set are considered to be unconstrained and will run with no
1140ab84d31eSPaul Turner	  restriction.
1141d6a3b247SMauro Carvalho Chehab	  See Documentation/scheduler/sched-bwc.rst for more information.
1142ab84d31eSPaul Turner
11437c941438SDhaval Gianiconfig RT_GROUP_SCHED
11447c941438SDhaval Giani	bool "Group scheduling for SCHED_RR/FIFO"
11457c941438SDhaval Giani	depends on CGROUP_SCHED
11467c941438SDhaval Giani	default n
11477c941438SDhaval Giani	help
11487c941438SDhaval Giani	  This feature lets you explicitly allocate real CPU bandwidth
114932bd7eb5SLi Zefan	  to task groups. If enabled, it will also make it impossible to
11507c941438SDhaval Giani	  schedule realtime tasks for non-root users until you allocate
11517c941438SDhaval Giani	  realtime bandwidth for them.
1152d6a3b247SMauro Carvalho Chehab	  See Documentation/scheduler/sched-rt-group.rst for more information.
11537c941438SDhaval Giani
1154e34e0131SMichal Koutnýconfig RT_GROUP_SCHED_DEFAULT_DISABLED
1155e34e0131SMichal Koutný	bool "Require boot parameter to enable group scheduling for SCHED_RR/FIFO"
1156e34e0131SMichal Koutný	depends on RT_GROUP_SCHED
1157e34e0131SMichal Koutný	default n
1158e34e0131SMichal Koutný	help
1159e34e0131SMichal Koutný	  When set, the RT group scheduling is disabled by default. The option
1160e34e0131SMichal Koutný	  is in inverted form so that mere RT_GROUP_SCHED enables the group
1161e34e0131SMichal Koutný	  scheduling.
1162e34e0131SMichal Koutný
1163e34e0131SMichal Koutný	  Say N if unsure.
1164e34e0131SMichal Koutný
116581951366STejun Heoconfig EXT_GROUP_SCHED
116681951366STejun Heo	bool
116781951366STejun Heo	depends on SCHED_CLASS_EXT && CGROUP_SCHED
116881951366STejun Heo	select GROUP_SCHED_WEIGHT
1169ddceadceSTejun Heo	select GROUP_SCHED_BANDWIDTH
117081951366STejun Heo	default y
117181951366STejun Heo
11727c941438SDhaval Gianiendif #CGROUP_SCHED
11737c941438SDhaval Giani
1174af7f588dSMathieu Desnoyersconfig SCHED_MM_CID
1175af7f588dSMathieu Desnoyers	def_bool y
1176af7f588dSMathieu Desnoyers	depends on SMP && RSEQ
1177af7f588dSMathieu Desnoyers
11782480c093SPatrick Bellasiconfig UCLAMP_TASK_GROUP
11792480c093SPatrick Bellasi	bool "Utilization clamping per group of tasks"
11802480c093SPatrick Bellasi	depends on CGROUP_SCHED
11812480c093SPatrick Bellasi	depends on UCLAMP_TASK
11822480c093SPatrick Bellasi	default n
11832480c093SPatrick Bellasi	help
11842480c093SPatrick Bellasi	  This feature enables the scheduler to track the clamped utilization
11852480c093SPatrick Bellasi	  of each CPU based on RUNNABLE tasks currently scheduled on that CPU.
11862480c093SPatrick Bellasi
11872480c093SPatrick Bellasi	  When this option is enabled, the user can specify a min and max
11882480c093SPatrick Bellasi	  CPU bandwidth which is allowed for each single task in a group.
11892480c093SPatrick Bellasi	  The max bandwidth allows to clamp the maximum frequency a task
11902480c093SPatrick Bellasi	  can use, while the min bandwidth allows to define a minimum
11912480c093SPatrick Bellasi	  frequency a task will always use.
11922480c093SPatrick Bellasi
11932480c093SPatrick Bellasi	  When task group based utilization clamping is enabled, an eventually
11942480c093SPatrick Bellasi	  specified task-specific clamp value is constrained by the cgroup
11952480c093SPatrick Bellasi	  specified clamp value. Both minimum and maximum task clamping cannot
11962480c093SPatrick Bellasi	  be bigger than the corresponding clamping defined at task group level.
11972480c093SPatrick Bellasi
11982480c093SPatrick Bellasi	  If in doubt, say N.
11992480c093SPatrick Bellasi
12006bf024e6SJohannes Weinerconfig CGROUP_PIDS
12016bf024e6SJohannes Weiner	bool "PIDs controller"
12026bf024e6SJohannes Weiner	help
12036bf024e6SJohannes Weiner	  Provides enforcement of process number limits in the scope of a
12046bf024e6SJohannes Weiner	  cgroup. Any attempt to fork more processes than is allowed in the
12056bf024e6SJohannes Weiner	  cgroup will fail. PIDs are fundamentally a global resource because it
12066bf024e6SJohannes Weiner	  is fairly trivial to reach PID exhaustion before you reach even a
12076bf024e6SJohannes Weiner	  conservative kmemcg limit. As a result, it is possible to grind a
12086bf024e6SJohannes Weiner	  system to halt without being limited by other cgroup policies. The
12096cc578dfSParav Pandit	  PIDs controller is designed to stop this from happening.
12106bf024e6SJohannes Weiner
12116bf024e6SJohannes Weiner	  It should be noted that organisational operations (such as attaching
121298076833SJonathan Neuschäfer	  to a cgroup hierarchy) will *not* be blocked by the PIDs controller,
12136bf024e6SJohannes Weiner	  since the PIDs limit only affects a process's ability to fork, not to
12146bf024e6SJohannes Weiner	  attach to a cgroup.
12156bf024e6SJohannes Weiner
121639d3e758SParav Panditconfig CGROUP_RDMA
121739d3e758SParav Pandit	bool "RDMA controller"
121839d3e758SParav Pandit	help
121939d3e758SParav Pandit	  Provides enforcement of RDMA resources defined by IB stack.
122039d3e758SParav Pandit	  It is fairly easy for consumers to exhaust RDMA resources, which
122139d3e758SParav Pandit	  can result into resource unavailability to other consumers.
122239d3e758SParav Pandit	  RDMA controller is designed to stop this from happening.
122339d3e758SParav Pandit	  Attaching processes with active RDMA resources to the cgroup
122439d3e758SParav Pandit	  hierarchy is allowed even if can cross the hierarchy's limit.
122539d3e758SParav Pandit
1226b168ed45SMaarten Lankhorstconfig CGROUP_DMEM
1227b168ed45SMaarten Lankhorst	bool "Device memory controller (DMEM)"
1228e33b5149SMaxime Ripard	select PAGE_COUNTER
1229b168ed45SMaarten Lankhorst	help
1230b168ed45SMaarten Lankhorst	  The DMEM controller allows compatible devices to restrict device
1231b168ed45SMaarten Lankhorst	  memory usage based on the cgroup hierarchy.
1232b168ed45SMaarten Lankhorst
1233b168ed45SMaarten Lankhorst	  As an example, it allows you to restrict VRAM usage for applications
1234b168ed45SMaarten Lankhorst	  in the DRM subsystem.
1235b168ed45SMaarten Lankhorst
12366bf024e6SJohannes Weinerconfig CGROUP_FREEZER
12376bf024e6SJohannes Weiner	bool "Freezer controller"
12386bf024e6SJohannes Weiner	help
12396bf024e6SJohannes Weiner	  Provides a way to freeze and unfreeze all tasks in a
12406bf024e6SJohannes Weiner	  cgroup.
12416bf024e6SJohannes Weiner
1242489c2a20SJohannes Weiner	  This option affects the ORIGINAL cgroup interface. The cgroup2 memory
1243489c2a20SJohannes Weiner	  controller includes important in-kernel memory consumers per default.
1244489c2a20SJohannes Weiner
1245489c2a20SJohannes Weiner	  If you're using cgroup2, say N.
1246489c2a20SJohannes Weiner
12476bf024e6SJohannes Weinerconfig CGROUP_HUGETLB
12486bf024e6SJohannes Weiner	bool "HugeTLB controller"
12496bf024e6SJohannes Weiner	depends on HUGETLB_PAGE
12506bf024e6SJohannes Weiner	select PAGE_COUNTER
1251afc24d49SVivek Goyal	default n
12526bf024e6SJohannes Weiner	help
12536bf024e6SJohannes Weiner	  Provides a cgroup controller for HugeTLB pages.
12546bf024e6SJohannes Weiner	  When you enable this, you can put a per cgroup limit on HugeTLB usage.
12556bf024e6SJohannes Weiner	  The limit is enforced during page fault. Since HugeTLB doesn't
12566bf024e6SJohannes Weiner	  support page reclaim, enforcing the limit at page fault time implies
12576bf024e6SJohannes Weiner	  that, the application will get SIGBUS signal if it tries to access
12586bf024e6SJohannes Weiner	  HugeTLB pages beyond its limit. This requires the application to know
12596bf024e6SJohannes Weiner	  beforehand how much HugeTLB pages it would require for its use. The
12606bf024e6SJohannes Weiner	  control group is tracked in the third page lru pointer. This means
12616bf024e6SJohannes Weiner	  that we cannot use the controller with huge page less than 3 pages.
1262afc24d49SVivek Goyal
12636bf024e6SJohannes Weinerconfig CPUSETS
12646bf024e6SJohannes Weiner	bool "Cpuset controller"
1265e1d4eeecSNicolas Pitre	depends on SMP
1266bf9850f6SKuan-Wei Chiu	select UNION_FIND
126723f09dccSFrederic Weisbecker	select CPU_ISOLATION
12686bf024e6SJohannes Weiner	help
12696bf024e6SJohannes Weiner	  This option will let you create and manage CPUSETs which
12706bf024e6SJohannes Weiner	  allow dynamically partitioning a system into sets of CPUs and
12716bf024e6SJohannes Weiner	  Memory Nodes and assigning tasks to run only within those sets.
12726bf024e6SJohannes Weiner	  This is primarily useful on large SMP or NUMA systems.
1273afc24d49SVivek Goyal
12746bf024e6SJohannes Weiner	  Say N if unsure.
1275afc24d49SVivek Goyal
12761abab1baSChen Ridongconfig CPUSETS_V1
12771abab1baSChen Ridong	bool "Legacy cgroup v1 cpusets controller"
12781abab1baSChen Ridong	depends on CPUSETS
12791abab1baSChen Ridong	default n
12801abab1baSChen Ridong	help
12811abab1baSChen Ridong	  Legacy cgroup v1 cpusets controller which has been deprecated by
12821abab1baSChen Ridong	  cgroup v2 implementation. The v1 is there for legacy applications
1283dae68fbaSMichal Koutný	  which haven't migrated to the new cgroup v2 interface yet. Legacy
1284dae68fbaSMichal Koutný	  interface includes cpuset filesystem and /proc/<pid>/cpuset. If you
12851abab1baSChen Ridong	  do not have any such application then you are completely fine leaving
12861abab1baSChen Ridong	  this option disabled.
12871abab1baSChen Ridong
12881abab1baSChen Ridong	  Say N if unsure.
12891abab1baSChen Ridong
12906bf024e6SJohannes Weinerconfig PROC_PID_CPUSET
12916bf024e6SJohannes Weiner	bool "Include legacy /proc/<pid>/cpuset file"
1292dae68fbaSMichal Koutný	depends on CPUSETS_V1
129389e9b9e0STejun Heo	default y
129489e9b9e0STejun Heo
12956bf024e6SJohannes Weinerconfig CGROUP_DEVICE
12966bf024e6SJohannes Weiner	bool "Device controller"
12976bf024e6SJohannes Weiner	help
12986bf024e6SJohannes Weiner	  Provides a cgroup controller implementing whitelists for
12996bf024e6SJohannes Weiner	  devices which a process in the cgroup can mknod or open.
13006bf024e6SJohannes Weiner
13016bf024e6SJohannes Weinerconfig CGROUP_CPUACCT
13026bf024e6SJohannes Weiner	bool "Simple CPU accounting controller"
13036bf024e6SJohannes Weiner	help
13046bf024e6SJohannes Weiner	  Provides a simple controller for monitoring the
13056bf024e6SJohannes Weiner	  total CPU consumed by the tasks in a cgroup.
13066bf024e6SJohannes Weiner
13076bf024e6SJohannes Weinerconfig CGROUP_PERF
13086bf024e6SJohannes Weiner	bool "Perf controller"
13096bf024e6SJohannes Weiner	depends on PERF_EVENTS
13106bf024e6SJohannes Weiner	help
13116bf024e6SJohannes Weiner	  This option extends the perf per-cpu mode to restrict monitoring
13126bf024e6SJohannes Weiner	  to threads which belong to the cgroup specified and run on the
13136546b19fSNamhyung Kim	  designated cpu.  Or this can be used to have cgroup ID in samples
13146546b19fSNamhyung Kim	  so that it can monitor performance events among cgroups.
13156bf024e6SJohannes Weiner
13166bf024e6SJohannes Weiner	  Say N if unsure.
13176bf024e6SJohannes Weiner
131830070984SDaniel Mackconfig CGROUP_BPF
131930070984SDaniel Mack	bool "Support for eBPF programs attached to cgroups"
1320483c4933SAndy Lutomirski	depends on BPF_SYSCALL
1321483c4933SAndy Lutomirski	select SOCK_CGROUP_DATA
132230070984SDaniel Mack	help
132330070984SDaniel Mack	  Allow attaching eBPF programs to a cgroup using the bpf(2)
132430070984SDaniel Mack	  syscall command BPF_PROG_ATTACH.
132530070984SDaniel Mack
132630070984SDaniel Mack	  In which context these programs are accessed depends on the type
132730070984SDaniel Mack	  of attachment. For instance, programs that are attached using
132830070984SDaniel Mack	  BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
132930070984SDaniel Mack	  inet sockets.
133030070984SDaniel Mack
1331a72232eaSVipin Sharmaconfig CGROUP_MISC
1332a72232eaSVipin Sharma	bool "Misc resource controller"
1333a72232eaSVipin Sharma	default n
1334a72232eaSVipin Sharma	help
1335a72232eaSVipin Sharma	  Provides a controller for miscellaneous resources on a host.
1336a72232eaSVipin Sharma
1337a72232eaSVipin Sharma	  Miscellaneous scalar resources are the resources on the host system
1338a72232eaSVipin Sharma	  which cannot be abstracted like the other cgroups. This controller
1339a72232eaSVipin Sharma	  tracks and limits the miscellaneous resources used by a process
1340a72232eaSVipin Sharma	  attached to a cgroup hierarchy.
1341a72232eaSVipin Sharma
1342a72232eaSVipin Sharma	  For more information, please check misc cgroup section in
1343a72232eaSVipin Sharma	  /Documentation/admin-guide/cgroup-v2.rst.
1344a72232eaSVipin Sharma
13456bf024e6SJohannes Weinerconfig CGROUP_DEBUG
134623b0be48SWaiman Long	bool "Debug controller"
13476bf024e6SJohannes Weiner	default n
134823b0be48SWaiman Long	depends on DEBUG_KERNEL
13496bf024e6SJohannes Weiner	help
13506bf024e6SJohannes Weiner	  This option enables a simple controller that exports
135123b0be48SWaiman Long	  debugging information about the cgroups framework. This
135223b0be48SWaiman Long	  controller is for control cgroup debugging only. Its
135323b0be48SWaiman Long	  interfaces are not stable.
13546bf024e6SJohannes Weiner
13556bf024e6SJohannes Weiner	  Say N.
13566bf024e6SJohannes Weiner
135773b35147SArnd Bergmannconfig SOCK_CGROUP_DATA
135873b35147SArnd Bergmann	bool
135973b35147SArnd Bergmann	default n
136073b35147SArnd Bergmann
136123964d2dSLi Zefanendif # CGROUPS
1362c077719bSKAMEZAWA Hiroyuki
13638dd2a82cSDaniel Lezcanomenuconfig NAMESPACES
13646a108a14SDavid Rientjes	bool "Namespaces support" if EXPERT
13652813893fSIulia Manda	depends on MULTIUSER
13666a108a14SDavid Rientjes	default !EXPERT
1367c5289a69SPavel Emelyanov	help
1368c5289a69SPavel Emelyanov	  Provides the way to make tasks work with different objects using
1369c5289a69SPavel Emelyanov	  the same id. For example same IPC id may refer to different objects
1370c5289a69SPavel Emelyanov	  or same user id or pid may refer to different tasks when used in
1371c5289a69SPavel Emelyanov	  different namespaces.
1372c5289a69SPavel Emelyanov
13738dd2a82cSDaniel Lezcanoif NAMESPACES
13748dd2a82cSDaniel Lezcano
137558bfdd6dSPavel Emelyanovconfig UTS_NS
137658bfdd6dSPavel Emelyanov	bool "UTS namespace"
137717a6d441SDaniel Lezcano	default y
137858bfdd6dSPavel Emelyanov	help
137958bfdd6dSPavel Emelyanov	  In this namespace tasks see different info provided with the
138058bfdd6dSPavel Emelyanov	  uname() system call
138158bfdd6dSPavel Emelyanov
1382769071acSAndrei Vaginconfig TIME_NS
1383769071acSAndrei Vagin	bool "TIME namespace"
1384bad53ae2SThomas Weißschuh	depends on GENERIC_GETTIMEOFDAY
1385769071acSAndrei Vagin	default y
1386769071acSAndrei Vagin	help
1387769071acSAndrei Vagin	  In this namespace boottime and monotonic clocks can be set.
1388769071acSAndrei Vagin	  The time will keep going with the same pace.
1389769071acSAndrei Vagin
1390ae5e1b22SPavel Emelyanovconfig IPC_NS
1391ae5e1b22SPavel Emelyanov	bool "IPC namespace"
13928dd2a82cSDaniel Lezcano	depends on (SYSVIPC || POSIX_MQUEUE)
139317a6d441SDaniel Lezcano	default y
1394ae5e1b22SPavel Emelyanov	help
1395ae5e1b22SPavel Emelyanov	  In this namespace tasks work with IPC ids which correspond to
1396614b84cfSSerge E. Hallyn	  different IPC objects in different namespaces.
1397ae5e1b22SPavel Emelyanov
1398aee16ce7SPavel Emelyanovconfig USER_NS
139919c92399SKees Cook	bool "User namespace"
14005673a94cSEric W. Biederman	default n
1401aee16ce7SPavel Emelyanov	help
1402aee16ce7SPavel Emelyanov	  This allows containers, i.e. vservers, to use user namespaces
1403aee16ce7SPavel Emelyanov	  to provide different user info for different servers.
1404e11f0ae3SEric W. Biederman
1405e11f0ae3SEric W. Biederman	  When user namespaces are enabled in the kernel it is
1406d886f4e4SJohannes Weiner	  recommended that the MEMCG option also be enabled and that
1407d886f4e4SJohannes Weiner	  user-space use the memory control groups to limit the amount
1408d886f4e4SJohannes Weiner	  of memory a memory unprivileged users can use.
1409e11f0ae3SEric W. Biederman
1410aee16ce7SPavel Emelyanov	  If unsure, say N.
1411aee16ce7SPavel Emelyanov
141274bd59bbSPavel Emelyanovconfig PID_NS
14139bd38c2cSDaniel Lezcano	bool "PID Namespaces"
141417a6d441SDaniel Lezcano	default y
141574bd59bbSPavel Emelyanov	help
141612d2b8f9SHeikki Orsila	  Support process id namespaces.  This allows having multiple
1417692105b8SMatt LaPlante	  processes with the same pid as long as they are in different
141874bd59bbSPavel Emelyanov	  pid namespaces.  This is a building block of containers.
141974bd59bbSPavel Emelyanov
1420d6eb633fSMatt Helsleyconfig NET_NS
1421d6eb633fSMatt Helsley	bool "Network namespace"
14228dd2a82cSDaniel Lezcano	depends on NET
142317a6d441SDaniel Lezcano	default y
1424d6eb633fSMatt Helsley	help
1425d6eb633fSMatt Helsley	  Allow user space to create what appear to be multiple instances
1426d6eb633fSMatt Helsley	  of the network stack.
1427d6eb633fSMatt Helsley
14288dd2a82cSDaniel Lezcanoendif # NAMESPACES
14298dd2a82cSDaniel Lezcano
14305cb366bbSAdrian Reberconfig CHECKPOINT_RESTORE
14315cb366bbSAdrian Reber	bool "Checkpoint/restore support"
143230341ec9SRen Zhijie	depends on PROC_FS
14335cb366bbSAdrian Reber	select PROC_CHILDREN
1434bfe3911aSChris Wilson	select KCMP
14355cb366bbSAdrian Reber	default n
14365cb366bbSAdrian Reber	help
14375cb366bbSAdrian Reber	  Enables additional kernel features in a sake of checkpoint/restore.
14385cb366bbSAdrian Reber	  In particular it adds auxiliary prctl codes to setup process text,
14395cb366bbSAdrian Reber	  data and heap segment sizes, and a few additional /proc filesystem
14405cb366bbSAdrian Reber	  entries.
14415cb366bbSAdrian Reber
14425cb366bbSAdrian Reber	  If unsure, say N here.
14435cb366bbSAdrian Reber
14445091faa4SMike Galbraithconfig SCHED_AUTOGROUP
14455091faa4SMike Galbraith	bool "Automatic process group scheduling"
14465091faa4SMike Galbraith	select CGROUPS
14475091faa4SMike Galbraith	select CGROUP_SCHED
14485091faa4SMike Galbraith	select FAIR_GROUP_SCHED
14495091faa4SMike Galbraith	help
14505091faa4SMike Galbraith	  This option optimizes the scheduler for common desktop workloads by
14515091faa4SMike Galbraith	  automatically creating and populating task groups.  This separation
14525091faa4SMike Galbraith	  of workloads isolates aggressive CPU burners (like build jobs) from
14535091faa4SMike Galbraith	  desktop applications.  Task group autogeneration is currently based
14545091faa4SMike Galbraith	  upon task session.
14555091faa4SMike Galbraith
14567af37becSDaniel Lezcanoconfig RELAY
14577af37becSDaniel Lezcano	bool "Kernel->user space relay support (formerly relayfs)"
145826b5679eSPeter Zijlstra	select IRQ_WORK
14597af37becSDaniel Lezcano	help
14607af37becSDaniel Lezcano	  This option enables support for relay interface support in
14617af37becSDaniel Lezcano	  certain file systems (such as debugfs).
14627af37becSDaniel Lezcano	  It is designed to provide an efficient mechanism for tools and
14637af37becSDaniel Lezcano	  facilities to relay large amounts of data from kernel space to
14647af37becSDaniel Lezcano	  user space.
14657af37becSDaniel Lezcano
14667af37becSDaniel Lezcano	  If unsure, say N.
14677af37becSDaniel Lezcano
1468f991633dSDimitri Gorokhovikconfig BLK_DEV_INITRD
1469f991633dSDimitri Gorokhovik	bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1470f991633dSDimitri Gorokhovik	help
1471f991633dSDimitri Gorokhovik	  The initial RAM filesystem is a ramfs which is loaded by the
1472f991633dSDimitri Gorokhovik	  boot loader (loadlin or lilo) and that is mounted as root
1473f991633dSDimitri Gorokhovik	  before the normal boot procedure. It is typically used to
1474f991633dSDimitri Gorokhovik	  load modules needed to mount the "real" root file system,
14758c27ceffSMauro Carvalho Chehab	  etc. See <file:Documentation/admin-guide/initrd.rst> for details.
1476f991633dSDimitri Gorokhovik
1477f991633dSDimitri Gorokhovik	  If RAM disk support (BLK_DEV_RAM) is also included, this
1478f991633dSDimitri Gorokhovik	  also enables initial RAM disk (initrd) support and adds
1479f991633dSDimitri Gorokhovik	  15 Kbytes (more on some other architectures) to the kernel size.
1480f991633dSDimitri Gorokhovik
1481f991633dSDimitri Gorokhovik	  If unsure say Y.
1482f991633dSDimitri Gorokhovik
1483c33df4eaSJean-Paul Samanif BLK_DEV_INITRD
1484c33df4eaSJean-Paul Saman
1485dbec4866SSam Ravnborgsource "usr/Kconfig"
1486dbec4866SSam Ravnborg
1487c33df4eaSJean-Paul Samanendif
1488c33df4eaSJean-Paul Saman
148976db5a27SMasami Hiramatsuconfig BOOT_CONFIG
149076db5a27SMasami Hiramatsu	bool "Boot config support"
1491a2a9d67aSMasami Hiramatsu	select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED
149276db5a27SMasami Hiramatsu	help
149376db5a27SMasami Hiramatsu	  Extra boot config allows system admin to pass a config file as
149476db5a27SMasami Hiramatsu	  complemental extension of kernel cmdline when booting.
14950947db01SMasami Hiramatsu	  The boot config file must be attached at the end of initramfs
149685c46b78SMasami Hiramatsu	  with checksum, size and magic word.
14970947db01SMasami Hiramatsu	  See <file:Documentation/admin-guide/bootconfig.rst> for details.
149876db5a27SMasami Hiramatsu
149976db5a27SMasami Hiramatsu	  If unsure, say Y.
150076db5a27SMasami Hiramatsu
1501b743852cSPaul E. McKenneyconfig BOOT_CONFIG_FORCE
1502b743852cSPaul E. McKenney	bool "Force unconditional bootconfig processing"
1503b743852cSPaul E. McKenney	depends on BOOT_CONFIG
15046ded8a28SPaul E. McKenney	default y if BOOT_CONFIG_EMBED
1505b743852cSPaul E. McKenney	help
1506b743852cSPaul E. McKenney	  With this Kconfig option set, BOOT_CONFIG processing is carried
1507b743852cSPaul E. McKenney	  out even when the "bootconfig" kernel-boot parameter is omitted.
1508b743852cSPaul E. McKenney	  In fact, with this Kconfig option set, there is no way to
1509b743852cSPaul E. McKenney	  make the kernel ignore the BOOT_CONFIG-supplied kernel-boot
1510b743852cSPaul E. McKenney	  parameters.
1511b743852cSPaul E. McKenney
1512b743852cSPaul E. McKenney	  If unsure, say N.
1513b743852cSPaul E. McKenney
1514a2a9d67aSMasami Hiramatsuconfig BOOT_CONFIG_EMBED
1515a2a9d67aSMasami Hiramatsu	bool "Embed bootconfig file in the kernel"
1516a2a9d67aSMasami Hiramatsu	depends on BOOT_CONFIG
1517a2a9d67aSMasami Hiramatsu	help
1518a2a9d67aSMasami Hiramatsu	  Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the
1519a2a9d67aSMasami Hiramatsu	  kernel. Usually, the bootconfig file is loaded with the initrd
1520a2a9d67aSMasami Hiramatsu	  image. But if the system doesn't support initrd, this option will
1521a2a9d67aSMasami Hiramatsu	  help you by embedding a bootconfig file while building the kernel.
1522a2a9d67aSMasami Hiramatsu
1523a2a9d67aSMasami Hiramatsu	  If unsure, say N.
1524a2a9d67aSMasami Hiramatsu
1525a2a9d67aSMasami Hiramatsuconfig BOOT_CONFIG_EMBED_FILE
1526a2a9d67aSMasami Hiramatsu	string "Embedded bootconfig file path"
1527a2a9d67aSMasami Hiramatsu	depends on BOOT_CONFIG_EMBED
1528a2a9d67aSMasami Hiramatsu	help
1529a2a9d67aSMasami Hiramatsu	  Specify a bootconfig file which will be embedded to the kernel.
1530a2a9d67aSMasami Hiramatsu	  This bootconfig will be used if there is no initrd or no other
1531a2a9d67aSMasami Hiramatsu	  bootconfig in the initrd.
1532a2a9d67aSMasami Hiramatsu
1533032a7302SDouglas Andersonconfig CMDLINE_LOG_WRAP_IDEAL_LEN
1534032a7302SDouglas Anderson	int "Length to try to wrap the cmdline when logged at boot"
1535032a7302SDouglas Anderson	default 1021
1536032a7302SDouglas Anderson	range 0 1021
1537032a7302SDouglas Anderson	help
1538032a7302SDouglas Anderson	  At boot time, the kernel command line is logged to the console.
1539032a7302SDouglas Anderson	  The log message will start with the prefix "Kernel command line: ".
1540032a7302SDouglas Anderson	  The log message will attempt to be wrapped (split into multiple log
1541032a7302SDouglas Anderson	  messages) at spaces based on CMDLINE_LOG_WRAP_IDEAL_LEN characters.
1542032a7302SDouglas Anderson	  If wrapping happens, each log message will start with the prefix and
1543032a7302SDouglas Anderson	  all but the last message will end with " \". Messages may exceed the
1544032a7302SDouglas Anderson	  ideal length if a place to wrap isn't found before the specified
1545032a7302SDouglas Anderson	  number of characters.
1546032a7302SDouglas Anderson
1547032a7302SDouglas Anderson	  A value of 0 disables wrapping, though be warned that the maximum
1548032a7302SDouglas Anderson	  length of a log message (1021 characters) may cause the cmdline to
1549032a7302SDouglas Anderson	  be truncated.
1550032a7302SDouglas Anderson
15511274aea1SDavid Disseldorpconfig INITRAMFS_PRESERVE_MTIME
15521274aea1SDavid Disseldorp	bool "Preserve cpio archive mtimes in initramfs"
155374792608SGeert Uytterhoeven	depends on BLK_DEV_INITRD
15541274aea1SDavid Disseldorp	default y
15551274aea1SDavid Disseldorp	help
15561274aea1SDavid Disseldorp	  Each entry in an initramfs cpio archive carries an mtime value. When
15571274aea1SDavid Disseldorp	  enabled, extracted cpio items take this mtime, with directory mtime
15581274aea1SDavid Disseldorp	  setting deferred until after creation of any child entries.
15591274aea1SDavid Disseldorp
15601274aea1SDavid Disseldorp	  If unsure, say Y.
15611274aea1SDavid Disseldorp
156283c0b272SDavid Disseldorpconfig INITRAMFS_TEST
156383c0b272SDavid Disseldorp	bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS
156483c0b272SDavid Disseldorp	depends on BLK_DEV_INITRD && KUNIT=y
156583c0b272SDavid Disseldorp	default KUNIT_ALL_TESTS
156683c0b272SDavid Disseldorp	help
156783c0b272SDavid Disseldorp	  Build KUnit tests for initramfs. See Documentation/dev-tools/kunit
156883c0b272SDavid Disseldorp
1569877417e6SArnd Bergmannchoice
1570877417e6SArnd Bergmann	prompt "Compiler optimization level"
15712cc3ce24SUlf Magnusson	default CC_OPTIMIZE_FOR_PERFORMANCE
1572877417e6SArnd Bergmann
1573877417e6SArnd Bergmannconfig CC_OPTIMIZE_FOR_PERFORMANCE
157415f5db60SMasahiro Yamada	bool "Optimize for performance (-O2)"
1575877417e6SArnd Bergmann	help
1576877417e6SArnd Bergmann	  This is the default optimization level for the kernel, building
1577877417e6SArnd Bergmann	  with the "-O2" compiler flag for best performance and most
1578877417e6SArnd Bergmann	  helpful compile-time warnings.
1579877417e6SArnd Bergmann
1580c45b4f1fSLinus Torvaldsconfig CC_OPTIMIZE_FOR_SIZE
158115f5db60SMasahiro Yamada	bool "Optimize for size (-Os)"
1582c45b4f1fSLinus Torvalds	help
1583ce3b487fSMasahiro Yamada	  Choosing this option will pass "-Os" to your compiler resulting
1584ce3b487fSMasahiro Yamada	  in a smaller kernel.
1585c45b4f1fSLinus Torvalds
1586877417e6SArnd Bergmannendchoice
1587877417e6SArnd Bergmann
15885d20ee31SNicholas Pigginconfig HAVE_LD_DEAD_CODE_DATA_ELIMINATION
15895d20ee31SNicholas Piggin	bool
15905d20ee31SNicholas Piggin	help
15915d20ee31SNicholas Piggin	  This requires that the arch annotates or otherwise protects
15925d20ee31SNicholas Piggin	  its external entry points from being discarded. Linker scripts
15935d20ee31SNicholas Piggin	  must also merge .text.*, .data.*, and .bss.* correctly into
15945d20ee31SNicholas Piggin	  output sections. Care must be taken not to pull in unrelated
15955d20ee31SNicholas Piggin	  sections (e.g., '.text.init'). Typically '.' in section names
15965d20ee31SNicholas Piggin	  is used to distinguish them from label names / C identifiers.
15975d20ee31SNicholas Piggin
15985d20ee31SNicholas Pigginconfig LD_DEAD_CODE_DATA_ELIMINATION
15995d20ee31SNicholas Piggin	bool "Dead code and data elimination (EXPERIMENTAL)"
16005d20ee31SNicholas Piggin	depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION
16015d20ee31SNicholas Piggin	depends on EXPERT
1602e85d1d65SMasahiro Yamada	depends on $(cc-option,-ffunction-sections -fdata-sections)
1603e85d1d65SMasahiro Yamada	depends on $(ld-option,--gc-sections)
16045d20ee31SNicholas Piggin	help
16058b9d2712SMasahiro Yamada	  Enable this if you want to do dead code and data elimination with
16068b9d2712SMasahiro Yamada	  the linker by compiling with -ffunction-sections -fdata-sections,
16078b9d2712SMasahiro Yamada	  and linking with --gc-sections.
16085d20ee31SNicholas Piggin
16095d20ee31SNicholas Piggin	  This can reduce on disk and in-memory size of the kernel
16105d20ee31SNicholas Piggin	  code and static data, particularly for small configs and
16115d20ee31SNicholas Piggin	  on small systems. This has the possibility of introducing
16125d20ee31SNicholas Piggin	  silently broken kernel if the required annotations are not
16135d20ee31SNicholas Piggin	  present. This option is not well tested yet, so use at your
16145d20ee31SNicholas Piggin	  own risk.
16155d20ee31SNicholas Piggin
161659612b24SNathan Chancellorconfig LD_ORPHAN_WARN
161759612b24SNathan Chancellor	def_bool y
161859612b24SNathan Chancellor	depends on ARCH_WANT_LD_ORPHAN_WARN
161959612b24SNathan Chancellor	depends on $(ld-option,--orphan-handling=warn)
1620e1789d7cSXin Li	depends on $(ld-option,--orphan-handling=error)
1621e1789d7cSXin Li
1622e1789d7cSXin Liconfig LD_ORPHAN_WARN_LEVEL
1623e1789d7cSXin Li        string
1624e1789d7cSXin Li        depends on LD_ORPHAN_WARN
1625e1789d7cSXin Li        default "error" if WERROR
1626e1789d7cSXin Li        default "warn"
162759612b24SNathan Chancellor
16280847062aSRandy Dunlapconfig SYSCTL
16290847062aSRandy Dunlap	bool
16300847062aSRandy Dunlap
1631657a5209SMike Frysingerconfig HAVE_UID16
1632657a5209SMike Frysinger	bool
1633657a5209SMike Frysinger
1634657a5209SMike Frysingerconfig SYSCTL_EXCEPTION_TRACE
1635657a5209SMike Frysinger	bool
1636657a5209SMike Frysinger	help
1637657a5209SMike Frysinger	  Enable support for /proc/sys/debug/exception-trace.
1638657a5209SMike Frysinger
1639657a5209SMike Frysingerconfig SYSCTL_ARCH_UNALIGN_NO_WARN
1640657a5209SMike Frysinger	bool
1641657a5209SMike Frysinger	help
1642657a5209SMike Frysinger	  Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1643657a5209SMike Frysinger	  Allows arch to define/use @no_unaligned_warning to possibly warn
1644657a5209SMike Frysinger	  about unaligned access emulation going on under the hood.
1645657a5209SMike Frysinger
1646657a5209SMike Frysingerconfig SYSCTL_ARCH_UNALIGN_ALLOW
1647657a5209SMike Frysinger	bool
1648657a5209SMike Frysinger	help
1649657a5209SMike Frysinger	  Enable support for /proc/sys/kernel/unaligned-trap
1650657a5209SMike Frysinger	  Allows arches to define/use @unaligned_enabled to runtime toggle
1651657a5209SMike Frysinger	  the unaligned access emulation.
1652657a5209SMike Frysinger	  see arch/parisc/kernel/unaligned.c for reference
1653657a5209SMike Frysinger
1654c443279aSChristian Braunerconfig SYSFS_SYSCALL
1655c443279aSChristian Brauner	bool "Sysfs syscall support"
1656c443279aSChristian Brauner	default n
1657c443279aSChristian Brauner	help
1658c443279aSChristian Brauner	  sys_sysfs is an obsolete system call no longer supported in libc.
1659c443279aSChristian Brauner	  Note that disabling this option is more secure but might break
1660c443279aSChristian Brauner	  compatibility with some systems.
1661c443279aSChristian Brauner
1662c443279aSChristian Brauner	  If unsure say N here.
1663c443279aSChristian Brauner
1664657a5209SMike Frysingerconfig HAVE_PCSPKR_PLATFORM
1665657a5209SMike Frysinger	bool
1666657a5209SMike Frysinger
16676a108a14SDavid Rientjesmenuconfig EXPERT
16686a108a14SDavid Rientjes	bool "Configure standard kernel features (expert users)"
1669f505c553SJosh Triplett	# Unhide debug options, to make the on-by-default options visible
1670f505c553SJosh Triplett	select DEBUG_KERNEL
16711da177e4SLinus Torvalds	help
16721da177e4SLinus Torvalds	  This option allows certain base kernel options and settings
16731da177e4SLinus Torvalds	  to be disabled or tweaked. This is for specialized
16741da177e4SLinus Torvalds	  environments which can tolerate a "non-standard" kernel.
16751da177e4SLinus Torvalds	  Only use this if you really know what you are doing.
16761da177e4SLinus Torvalds
1677ae81f9e3SChuck Ebbertconfig UID16
16786a108a14SDavid Rientjes	bool "Enable 16-bit UID system calls" if EXPERT
16792813893fSIulia Manda	depends on HAVE_UID16 && MULTIUSER
1680ae81f9e3SChuck Ebbert	default y
1681ae81f9e3SChuck Ebbert	help
1682ae81f9e3SChuck Ebbert	  This enables the legacy 16-bit UID syscall wrappers.
1683ae81f9e3SChuck Ebbert
16842813893fSIulia Mandaconfig MULTIUSER
16852813893fSIulia Manda	bool "Multiple users, groups and capabilities support" if EXPERT
16862813893fSIulia Manda	default y
16872813893fSIulia Manda	help
16882813893fSIulia Manda	  This option enables support for non-root users, groups and
16892813893fSIulia Manda	  capabilities.
16902813893fSIulia Manda
16912813893fSIulia Manda	  If you say N here, all processes will run with UID 0, GID 0, and all
16922813893fSIulia Manda	  possible capabilities.  Saying N here also compiles out support for
16932813893fSIulia Manda	  system calls related to UIDs, GIDs, and capabilities, such as setuid,
16942813893fSIulia Manda	  setgid, and capset.
16952813893fSIulia Manda
16962813893fSIulia Manda	  If unsure, say Y here.
16972813893fSIulia Manda
1698f6187769SFabian Frederickconfig SGETMASK_SYSCALL
1699f6187769SFabian Frederick	bool "sgetmask/ssetmask syscalls support" if EXPERT
1700cd14b018SMasahiro Yamada	default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH
1701a7f7f624SMasahiro Yamada	help
1702f6187769SFabian Frederick	  sys_sgetmask and sys_ssetmask are obsolete system calls
1703f6187769SFabian Frederick	  no longer supported in libc but still enabled by default in some
1704f6187769SFabian Frederick	  architectures.
1705f6187769SFabian Frederick
1706f6187769SFabian Frederick	  If unsure, leave the default option here.
1707f6187769SFabian Frederick
1708d1b069f5SRandy Dunlapconfig FHANDLE
1709d1b069f5SRandy Dunlap	bool "open by fhandle syscalls" if EXPERT
1710d1b069f5SRandy Dunlap	select EXPORTFS
1711d1b069f5SRandy Dunlap	default y
1712d1b069f5SRandy Dunlap	help
1713d1b069f5SRandy Dunlap	  If you say Y here, a user level program will be able to map
1714d1b069f5SRandy Dunlap	  file names to handle and then later use the handle for
1715d1b069f5SRandy Dunlap	  different file system operations. This is useful in implementing
1716d1b069f5SRandy Dunlap	  userspace file servers, which now track files using handles instead
1717d1b069f5SRandy Dunlap	  of names. The handle would remain the same even if file names
1718d1b069f5SRandy Dunlap	  get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
1719d1b069f5SRandy Dunlap	  syscalls.
1720d1b069f5SRandy Dunlap
1721baa73d9eSNicolas Pitreconfig POSIX_TIMERS
1722baa73d9eSNicolas Pitre	bool "Posix Clocks & timers" if EXPERT
1723baa73d9eSNicolas Pitre	default y
1724baa73d9eSNicolas Pitre	help
1725baa73d9eSNicolas Pitre	  This includes native support for POSIX timers to the kernel.
1726baa73d9eSNicolas Pitre	  Some embedded systems have no use for them and therefore they
1727baa73d9eSNicolas Pitre	  can be configured out to reduce the size of the kernel image.
1728baa73d9eSNicolas Pitre
1729baa73d9eSNicolas Pitre	  When this option is disabled, the following syscalls won't be
1730baa73d9eSNicolas Pitre	  available: timer_create, timer_gettime: timer_getoverrun,
1731baa73d9eSNicolas Pitre	  timer_settime, timer_delete, clock_adjtime, getitimer,
1732baa73d9eSNicolas Pitre	  setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
1733baa73d9eSNicolas Pitre	  clock_getres and clock_nanosleep syscalls will be limited to
1734baa73d9eSNicolas Pitre	  CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
1735baa73d9eSNicolas Pitre
1736baa73d9eSNicolas Pitre	  If unsure say y.
1737baa73d9eSNicolas Pitre
1738d59745ceSMatt Mackallconfig PRINTK
1739d59745ceSMatt Mackall	default y
17406a108a14SDavid Rientjes	bool "Enable support for printk" if EXPERT
174174876a98SFrederic Weisbecker	select IRQ_WORK
1742d59745ceSMatt Mackall	help
1743d59745ceSMatt Mackall	  This option enables normal printk support. Removing it
1744d59745ceSMatt Mackall	  eliminates most of the message strings from the kernel image
1745d59745ceSMatt Mackall	  and makes the kernel more or less silent. As this makes it
1746d59745ceSMatt Mackall	  very difficult to diagnose system problems, saying N here is
1747d59745ceSMatt Mackall	  strongly discouraged.
1748d59745ceSMatt Mackall
17495ea2bcdfSThomas Weißschuhconfig PRINTK_RINGBUFFER_KUNIT_TEST
17505ea2bcdfSThomas Weißschuh	tristate "KUnit Test for the printk ringbuffer" if !KUNIT_ALL_TESTS
17515ea2bcdfSThomas Weißschuh	depends on PRINTK && KUNIT
17525ea2bcdfSThomas Weißschuh	default KUNIT_ALL_TESTS
17535ea2bcdfSThomas Weißschuh	help
17545ea2bcdfSThomas Weißschuh	  This builds the printk ringbuffer KUnit test suite.
17555ea2bcdfSThomas Weißschuh
17565ea2bcdfSThomas Weißschuh	  For more information on KUnit and unit tests in general, please refer
17575ea2bcdfSThomas Weißschuh	  to the KUnit documentation.
17585ea2bcdfSThomas Weißschuh
17595ea2bcdfSThomas Weißschuh	  If unsure, say N.
17605ea2bcdfSThomas Weißschuh
1761c8538a7aSMatt Mackallconfig BUG
17626a108a14SDavid Rientjes	bool "BUG() support" if EXPERT
1763c8538a7aSMatt Mackall	default y
1764c8538a7aSMatt Mackall	help
1765c8538a7aSMatt Mackall	  Disabling this option eliminates support for BUG and WARN, reducing
1766c8538a7aSMatt Mackall	  the size of your kernel image and potentially quietly ignoring
1767c8538a7aSMatt Mackall	  numerous fatal conditions. You should only consider disabling this
1768c8538a7aSMatt Mackall	  option for embedded systems with no facilities for reporting errors.
1769c8538a7aSMatt Mackall	  Just say Y.
1770c8538a7aSMatt Mackall
1771708e9a79SMatt Mackallconfig ELF_CORE
1772046d662fSAlex Kelly	depends on COREDUMP
1773708e9a79SMatt Mackall	default y
17746a108a14SDavid Rientjes	bool "Enable ELF core dumps" if EXPERT
1775708e9a79SMatt Mackall	help
1776708e9a79SMatt Mackall	  Enable support for generating core dumps. Disabling saves about 4k.
1777708e9a79SMatt Mackall
17788761f1abSRalf Baechle
1779e5e1d3cbSStas Sergeevconfig PCSPKR_PLATFORM
17806a108a14SDavid Rientjes	bool "Enable PC-Speaker support" if EXPERT
17818761f1abSRalf Baechle	depends on HAVE_PCSPKR_PLATFORM
178215f304b6SRalf Baechle	select I8253_LOCK
1783e5e1d3cbSStas Sergeev	default y
1784e5e1d3cbSStas Sergeev	help
1785e5e1d3cbSStas Sergeev	  This option allows to disable the internal PC-Speaker
1786e5e1d3cbSStas Sergeev	  support, saving some memory.
1787e5e1d3cbSStas Sergeev
178827021649SYoann Congalconfig BASE_SMALL
178927021649SYoann Congal	bool "Enable smaller-sized data structures for core" if EXPERT
17901da177e4SLinus Torvalds	help
179127021649SYoann Congal	  Enabling this option reduces the size of miscellaneous core
17921da177e4SLinus Torvalds	  kernel data structures. This saves memory on small machines,
17931da177e4SLinus Torvalds	  but may reduce performance.
17941da177e4SLinus Torvalds
17951da177e4SLinus Torvaldsconfig FUTEX
17966a108a14SDavid Rientjes	bool "Enable futex support" if EXPERT
17973f2bedabSArnd Bergmann	depends on !(SPARC32 && SMP)
17981da177e4SLinus Torvalds	default y
1799bc2eecd7SNicolas Pitre	imply RT_MUTEXES
18001da177e4SLinus Torvalds	help
18011da177e4SLinus Torvalds	  Disabling this option will cause the kernel to be built without
18021da177e4SLinus Torvalds	  support for "fast userspace mutexes".  The resulting kernel may not
18031da177e4SLinus Torvalds	  run glibc-based applications correctly.
18041da177e4SLinus Torvalds
1805bc2eecd7SNicolas Pitreconfig FUTEX_PI
1806bc2eecd7SNicolas Pitre	bool
1807bc2eecd7SNicolas Pitre	depends on FUTEX && RT_MUTEXES
1808bc2eecd7SNicolas Pitre	default y
1809bc2eecd7SNicolas Pitre
181080367ad0SSebastian Andrzej Siewiorconfig FUTEX_PRIVATE_HASH
181180367ad0SSebastian Andrzej Siewior	bool
181280367ad0SSebastian Andrzej Siewior	depends on FUTEX && !BASE_SMALL && MMU
181380367ad0SSebastian Andrzej Siewior	default y
181480367ad0SSebastian Andrzej Siewior
1815c042c505SPeter Zijlstraconfig FUTEX_MPOL
1816c042c505SPeter Zijlstra	bool
1817c042c505SPeter Zijlstra	depends on FUTEX && NUMA
1818c042c505SPeter Zijlstra	default y
1819c042c505SPeter Zijlstra
18201da177e4SLinus Torvaldsconfig EPOLL
18216a108a14SDavid Rientjes	bool "Enable eventpoll support" if EXPERT
18221da177e4SLinus Torvalds	default y
18231da177e4SLinus Torvalds	help
18241da177e4SLinus Torvalds	  Disabling this option will cause the kernel to be built without
18251da177e4SLinus Torvalds	  support for epoll family of system calls.
18261da177e4SLinus Torvalds
1827fba2afaaSDavide Libenziconfig SIGNALFD
18286a108a14SDavid Rientjes	bool "Enable signalfd() system call" if EXPERT
1829fba2afaaSDavide Libenzi	default y
1830fba2afaaSDavide Libenzi	help
1831fba2afaaSDavide Libenzi	  Enable the signalfd() system call that allows to receive signals
1832fba2afaaSDavide Libenzi	  on a file descriptor.
1833fba2afaaSDavide Libenzi
1834fba2afaaSDavide Libenzi	  If unsure, say Y.
1835fba2afaaSDavide Libenzi
1836b215e283SDavide Libenziconfig TIMERFD
18376a108a14SDavid Rientjes	bool "Enable timerfd() system call" if EXPERT
1838b215e283SDavide Libenzi	default y
1839b215e283SDavide Libenzi	help
1840b215e283SDavide Libenzi	  Enable the timerfd() system call that allows to receive timer
1841b215e283SDavide Libenzi	  events on a file descriptor.
1842b215e283SDavide Libenzi
1843b215e283SDavide Libenzi	  If unsure, say Y.
1844b215e283SDavide Libenzi
1845e1ad7468SDavide Libenziconfig EVENTFD
18466a108a14SDavid Rientjes	bool "Enable eventfd() system call" if EXPERT
1847e1ad7468SDavide Libenzi	default y
1848e1ad7468SDavide Libenzi	help
1849e1ad7468SDavide Libenzi	  Enable the eventfd() system call that allows to receive both
1850e1ad7468SDavide Libenzi	  kernel notification (ie. KAIO) or userspace notifications.
1851e1ad7468SDavide Libenzi
1852e1ad7468SDavide Libenzi	  If unsure, say Y.
1853e1ad7468SDavide Libenzi
18541da177e4SLinus Torvaldsconfig SHMEM
18556a108a14SDavid Rientjes	bool "Use full shmem filesystem" if EXPERT
18561da177e4SLinus Torvalds	default y
18571da177e4SLinus Torvalds	depends on MMU
18581da177e4SLinus Torvalds	help
18591da177e4SLinus Torvalds	  The shmem is an internal filesystem used to manage shared memory.
18601da177e4SLinus Torvalds	  It is backed by swap and manages resource limits. It is also exported
18611da177e4SLinus Torvalds	  to userspace as tmpfs if TMPFS is enabled. Disabling this
18621da177e4SLinus Torvalds	  option replaces shmem and tmpfs with the much simpler ramfs code,
18631da177e4SLinus Torvalds	  which may be appropriate on small systems without swap.
18641da177e4SLinus Torvalds
1865ebf3f09cSThomas Petazzoniconfig AIO
18666a108a14SDavid Rientjes	bool "Enable AIO support" if EXPERT
1867ebf3f09cSThomas Petazzoni	default y
1868ebf3f09cSThomas Petazzoni	help
1869ebf3f09cSThomas Petazzoni	  This option enables POSIX asynchronous I/O which may by used
1870ebf3f09cSThomas Petazzoni	  by some high performance threaded applications. Disabling
1871ebf3f09cSThomas Petazzoni	  this option saves about 7k.
1872ebf3f09cSThomas Petazzoni
18732b188cc1SJens Axboeconfig IO_URING
18742b188cc1SJens Axboe	bool "Enable IO uring support" if EXPERT
1875561fb04aSJens Axboe	select IO_WQ
18762b188cc1SJens Axboe	default y
18772b188cc1SJens Axboe	help
18782b188cc1SJens Axboe	  This option enables support for the io_uring interface, enabling
18792b188cc1SJens Axboe	  applications to submit and complete IO through submission and
18802b188cc1SJens Axboe	  completion rings that are shared between the kernel and application.
18812b188cc1SJens Axboe
18821802656eSJens Axboeconfig GCOV_PROFILE_URING
18831802656eSJens Axboe	bool "Enable GCOV profiling on the io_uring subsystem"
1884d1fbe1ebSRandy Dunlap	depends on IO_URING && GCOV_KERNEL
18851802656eSJens Axboe	help
18861802656eSJens Axboe	  Enable GCOV profiling on the io_uring subsystem, to facilitate
18871802656eSJens Axboe	  code coverage testing.
18881802656eSJens Axboe
18891802656eSJens Axboe	  If unsure, say N.
18901802656eSJens Axboe
18911802656eSJens Axboe	  Note that this will have a negative impact on the performance of
18921802656eSJens Axboe	  the io_uring subsystem, hence this should only be enabled for
18931802656eSJens Axboe	  specific test purposes.
18941802656eSJens Axboe
18953a0ae385SPavel Begunkovconfig IO_URING_MOCK_FILE
18963a0ae385SPavel Begunkov	tristate "Enable io_uring mock files (Experimental)" if EXPERT
18973a0ae385SPavel Begunkov	default n
18983a0ae385SPavel Begunkov	depends on IO_URING
18993a0ae385SPavel Begunkov	help
1900*9e7dc228SJ. Neuschäfer	  Enable mock files for io_uring subsystem testing. The ABI might
19013a0ae385SPavel Begunkov	  still change, so it's still experimental and should only be enabled
19023a0ae385SPavel Begunkov	  for specific test purposes.
19033a0ae385SPavel Begunkov
19043a0ae385SPavel Begunkov	  If unsure, say N.
19053a0ae385SPavel Begunkov
1906d3ac21caSJosh Triplettconfig ADVISE_SYSCALLS
1907d3ac21caSJosh Triplett	bool "Enable madvise/fadvise syscalls" if EXPERT
1908d3ac21caSJosh Triplett	default y
1909d3ac21caSJosh Triplett	help
1910d3ac21caSJosh Triplett	  This option enables the madvise and fadvise syscalls, used by
1911d3ac21caSJosh Triplett	  applications to advise the kernel about their future memory or file
1912d3ac21caSJosh Triplett	  usage, improving performance. If building an embedded system where no
1913d3ac21caSJosh Triplett	  applications use these syscalls, you can disable this option to save
1914d3ac21caSJosh Triplett	  space.
1915d3ac21caSJosh Triplett
19165b25b13aSMathieu Desnoyersconfig MEMBARRIER
19175b25b13aSMathieu Desnoyers	bool "Enable membarrier() system call" if EXPERT
19185b25b13aSMathieu Desnoyers	default y
19195b25b13aSMathieu Desnoyers	help
19205b25b13aSMathieu Desnoyers	  Enable the membarrier() system call that allows issuing memory
19215b25b13aSMathieu Desnoyers	  barriers across all running threads, which can be used to distribute
19225b25b13aSMathieu Desnoyers	  the cost of user-space memory barriers asymmetrically by transforming
19235b25b13aSMathieu Desnoyers	  pairs of memory barriers into pairs consisting of membarrier() and a
19245b25b13aSMathieu Desnoyers	  compiler barrier.
19255b25b13aSMathieu Desnoyers
19265b25b13aSMathieu Desnoyers	  If unsure, say Y.
19275b25b13aSMathieu Desnoyers
1928a751ea34SRandy Dunlapconfig KCMP
1929a751ea34SRandy Dunlap	bool "Enable kcmp() system call" if EXPERT
1930a751ea34SRandy Dunlap	help
1931a751ea34SRandy Dunlap	  Enable the kernel resource comparison system call. It provides
1932a751ea34SRandy Dunlap	  user-space with the ability to compare two processes to see if they
1933a751ea34SRandy Dunlap	  share a common resource, such as a file descriptor or even virtual
1934a751ea34SRandy Dunlap	  memory space.
1935a751ea34SRandy Dunlap
1936a751ea34SRandy Dunlap	  If unsure, say N.
1937a751ea34SRandy Dunlap
1938a751ea34SRandy Dunlapconfig RSEQ
1939a751ea34SRandy Dunlap	bool "Enable rseq() system call" if EXPERT
1940a751ea34SRandy Dunlap	default y
1941a751ea34SRandy Dunlap	depends on HAVE_RSEQ
1942a751ea34SRandy Dunlap	select MEMBARRIER
1943a751ea34SRandy Dunlap	help
1944a751ea34SRandy Dunlap	  Enable the restartable sequences system call. It provides a
1945a751ea34SRandy Dunlap	  user-space cache for the current CPU number value, which
1946a751ea34SRandy Dunlap	  speeds up getting the current CPU number from user-space,
1947a751ea34SRandy Dunlap	  as well as an ABI to speed up user-space operations on
1948a751ea34SRandy Dunlap	  per-CPU data.
1949a751ea34SRandy Dunlap
1950a751ea34SRandy Dunlap	  If unsure, say Y.
1951a751ea34SRandy Dunlap
1952d7a5da7aSThomas Gleixnerconfig RSEQ_SLICE_EXTENSION
1953d7a5da7aSThomas Gleixner	bool "Enable rseq-based time slice extension mechanism"
1954d7a5da7aSThomas Gleixner	depends on RSEQ && HIGH_RES_TIMERS && GENERIC_ENTRY && HAVE_GENERIC_TIF_BITS
1955d7a5da7aSThomas Gleixner	help
1956d7a5da7aSThomas Gleixner	  Allows userspace to request a limited time slice extension when
1957d7a5da7aSThomas Gleixner	  returning from an interrupt to user space via the RSEQ shared
1958d7a5da7aSThomas Gleixner	  data ABI. If granted, that allows to complete a critical section,
1959d7a5da7aSThomas Gleixner	  so that other threads are not stuck on a conflicted resource,
1960d7a5da7aSThomas Gleixner	  while the task is scheduled out.
1961d7a5da7aSThomas Gleixner
1962d7a5da7aSThomas Gleixner	  If unsure, say N.
1963d7a5da7aSThomas Gleixner
196454129104SThomas Gleixnerconfig RSEQ_STATS
196554129104SThomas Gleixner	default n
196654129104SThomas Gleixner	bool "Enable lightweight statistics of restartable sequences" if EXPERT
196754129104SThomas Gleixner	depends on RSEQ && DEBUG_FS
196854129104SThomas Gleixner	help
196954129104SThomas Gleixner	  Enable lightweight counters which expose information about the
197054129104SThomas Gleixner	  frequency of RSEQ operations via debugfs. Mostly interesting for
197154129104SThomas Gleixner	  kernel debugging or performance analysis. While lightweight it's
197254129104SThomas Gleixner	  still adding code into the user/kernel mode transitions.
197354129104SThomas Gleixner
197454129104SThomas Gleixner	  If unsure, say N.
197554129104SThomas Gleixner
19769c37cb6eSThomas Gleixnerconfig RSEQ_DEBUG_DEFAULT_ENABLE
19779c37cb6eSThomas Gleixner	default n
19789c37cb6eSThomas Gleixner	bool "Enable restartable sequences debug mode by default" if EXPERT
19799c37cb6eSThomas Gleixner	depends on RSEQ
19809c37cb6eSThomas Gleixner	help
19819c37cb6eSThomas Gleixner	  This enables the static branch for debug mode of restartable
19829c37cb6eSThomas Gleixner	  sequences.
19839c37cb6eSThomas Gleixner
19849c37cb6eSThomas Gleixner	  This also can be controlled on the kernel command line via the
19859c37cb6eSThomas Gleixner	  command line parameter "rseq_debug=0/1" and through debugfs.
19869c37cb6eSThomas Gleixner
19879c37cb6eSThomas Gleixner	  If unsure, say N.
19889c37cb6eSThomas Gleixner
1989a751ea34SRandy Dunlapconfig DEBUG_RSEQ
1990a751ea34SRandy Dunlap	default n
1991a751ea34SRandy Dunlap	bool "Enable debugging of rseq() system call" if EXPERT
19923db6b38dSThomas Gleixner	depends on RSEQ && DEBUG_KERNEL && !GENERIC_ENTRY
19939c37cb6eSThomas Gleixner	select RSEQ_DEBUG_DEFAULT_ENABLE
1994a751ea34SRandy Dunlap	help
1995a751ea34SRandy Dunlap	  Enable extra debugging checks for the rseq system call.
1996a751ea34SRandy Dunlap
1997a751ea34SRandy Dunlap	  If unsure, say N.
1998a751ea34SRandy Dunlap
1999a751ea34SRandy Dunlapconfig CACHESTAT_SYSCALL
2000a751ea34SRandy Dunlap	bool "Enable cachestat() system call" if EXPERT
2001a751ea34SRandy Dunlap	default y
2002a751ea34SRandy Dunlap	help
2003a751ea34SRandy Dunlap	  Enable the cachestat system call, which queries the page cache
2004a751ea34SRandy Dunlap	  statistics of a file (number of cached pages, dirty pages,
2005a751ea34SRandy Dunlap	  pages marked for writeback, (recently) evicted pages).
2006a751ea34SRandy Dunlap
2007a751ea34SRandy Dunlap	  If unsure say Y here.
2008a751ea34SRandy Dunlap
2009d1b069f5SRandy Dunlapconfig KALLSYMS
2010d1b069f5SRandy Dunlap	bool "Load all symbols for debugging/ksymoops" if EXPERT
2011d1b069f5SRandy Dunlap	default y
2012d1b069f5SRandy Dunlap	help
2013d1b069f5SRandy Dunlap	  Say Y here to let the kernel print out symbolic crash information and
2014d1b069f5SRandy Dunlap	  symbolic stack backtraces. This increases the size of the kernel
2015d1b069f5SRandy Dunlap	  somewhat, as all symbols have to be loaded into the kernel image.
2016d1b069f5SRandy Dunlap
201730f3bb09SZhen Leiconfig KALLSYMS_SELFTEST
201830f3bb09SZhen Lei	bool "Test the basic functions and performance of kallsyms"
201930f3bb09SZhen Lei	depends on KALLSYMS
202030f3bb09SZhen Lei	default n
202130f3bb09SZhen Lei	help
202230f3bb09SZhen Lei	  Test the basic functions and performance of some interfaces, such as
202330f3bb09SZhen Lei	  kallsyms_lookup_name. It also calculates the compression rate of the
202430f3bb09SZhen Lei	  kallsyms compression algorithm for the current symbol set.
202530f3bb09SZhen Lei
202630f3bb09SZhen Lei	  Start self-test automatically after system startup. Suggest executing
202730f3bb09SZhen Lei	  "dmesg | grep kallsyms_selftest" to collect test results. "finish" is
202830f3bb09SZhen Lei	  displayed in the last line, indicating that the test is complete.
202930f3bb09SZhen Lei
2030d1b069f5SRandy Dunlapconfig KALLSYMS_ALL
2031d1b069f5SRandy Dunlap	bool "Include all symbols in kallsyms"
2032d1b069f5SRandy Dunlap	depends on DEBUG_KERNEL && KALLSYMS
2033d1b069f5SRandy Dunlap	help
2034d1b069f5SRandy Dunlap	  Normally kallsyms only contains the symbols of functions for nicer
2035d1b069f5SRandy Dunlap	  OOPS messages and backtraces (i.e., symbols from the text and inittext
2036bdf0fe33SBaruch Siach	  sections). This is sufficient for most cases. And only if you want to
2037bdf0fe33SBaruch Siach	  enable kernel live patching, or other less common use cases (e.g.,
2038bdf0fe33SBaruch Siach	  when a debugger is used) all symbols are required (i.e., names of
2039bdf0fe33SBaruch Siach	  variables from the data sections, etc).
2040d1b069f5SRandy Dunlap
2041d1b069f5SRandy Dunlap	  This option makes sure that all symbols are loaded into the kernel
2042d1b069f5SRandy Dunlap	  image (i.e., symbols from all sections) in cost of increased kernel
2043d1b069f5SRandy Dunlap	  size (depending on the kernel configuration, it may be 300KiB or
2044d1b069f5SRandy Dunlap	  something like this).
2045d1b069f5SRandy Dunlap
2046bdf0fe33SBaruch Siach	  Say N unless you really need all symbols, or kernel live patching.
2047d1b069f5SRandy Dunlap
2048d1b069f5SRandy Dunlap# end of the "standard kernel features (expert users)" menu
2049d1b069f5SRandy Dunlap
20503ccfebedSMathieu Desnoyersconfig ARCH_HAS_MEMBARRIER_CALLBACKS
20513ccfebedSMathieu Desnoyers	bool
20523ccfebedSMathieu Desnoyers
205370216e18SMathieu Desnoyersconfig ARCH_HAS_MEMBARRIER_SYNC_CORE
205470216e18SMathieu Desnoyers	bool
205570216e18SMathieu Desnoyers
20565796d396SJeff Xuconfig ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS
20575796d396SJeff Xu	bool
20585796d396SJeff Xu	help
20595796d396SJeff Xu	  Control MSEAL_SYSTEM_MAPPINGS access based on architecture.
20605796d396SJeff Xu
20615796d396SJeff Xu	  A 64-bit kernel is required for the memory sealing feature.
20625796d396SJeff Xu	  No specific hardware features from the CPU are needed.
20635796d396SJeff Xu
20645796d396SJeff Xu	  To enable this feature, the architecture needs to update their
20655796d396SJeff Xu	  special mappings calls to include the sealing flag and confirm
20665796d396SJeff Xu	  that it doesn't unmap/remap system mappings during the life
20675796d396SJeff Xu	  time of the process. The existence of this flag for an architecture
20685796d396SJeff Xu	  implies that it does not require the remapping of the system
20695796d396SJeff Xu	  mappings during process lifetime, so sealing these mappings is safe
20705796d396SJeff Xu	  from a kernel perspective.
20715796d396SJeff Xu
20725796d396SJeff Xu	  After the architecture enables this, a distribution can set
20735796d396SJeff Xu	  CONFIG_MSEAL_SYSTEM_MAPPING to manage access to the feature.
20745796d396SJeff Xu
20755796d396SJeff Xu	  For complete descriptions of memory sealing, please see
20765796d396SJeff Xu	  Documentation/userspace-api/mseal.rst
20775796d396SJeff Xu
2078cdd6c482SIngo Molnarconfig HAVE_PERF_EVENTS
20790793a61dSThomas Gleixner	bool
2080018df72dSMike Frysinger	help
2081018df72dSMike Frysinger	  See tools/perf/design.txt for details.
20820793a61dSThomas Gleixner
20832aef6f30SSean Christophersonconfig GUEST_PERF_EVENTS
20842aef6f30SSean Christopherson	bool
20852aef6f30SSean Christopherson	depends on HAVE_PERF_EVENTS
20862aef6f30SSean Christopherson
2087eff95e17SKan Liangconfig PERF_GUEST_MEDIATED_PMU
2088eff95e17SKan Liang	bool
2089eff95e17SKan Liang	depends on GUEST_PERF_EVENTS
2090eff95e17SKan Liang
2091906010b2SPeter Zijlstraconfig PERF_USE_VMALLOC
2092906010b2SPeter Zijlstra	bool
2093906010b2SPeter Zijlstra	help
2094906010b2SPeter Zijlstra	  See tools/perf/design.txt for details
2095906010b2SPeter Zijlstra
209657c0c15bSIngo Molnarmenu "Kernel Performance Events And Counters"
20970793a61dSThomas Gleixner
2098cdd6c482SIngo Molnarconfig PERF_EVENTS
209957c0c15bSIngo Molnar	bool "Kernel performance events and counters"
2100392d65a9SRobert Richter	default y if PROFILING
2101cdd6c482SIngo Molnar	depends on HAVE_PERF_EVENTS
2102e360adbeSPeter Zijlstra	select IRQ_WORK
21030793a61dSThomas Gleixner	help
210457c0c15bSIngo Molnar	  Enable kernel support for various performance events provided
210557c0c15bSIngo Molnar	  by software and hardware.
21060793a61dSThomas Gleixner
2107dd77038dSThadeu Lima de Souza Cascardo	  Software events are supported either built-in or via the
210857c0c15bSIngo Molnar	  use of generic tracepoints.
210957c0c15bSIngo Molnar
211057c0c15bSIngo Molnar	  Most modern CPUs support performance events via performance
211157c0c15bSIngo Molnar	  counter registers. These registers count the number of certain
21120793a61dSThomas Gleixner	  types of hw events: such as instructions executed, cachemisses
21130793a61dSThomas Gleixner	  suffered, or branches mis-predicted - without slowing down the
21140793a61dSThomas Gleixner	  kernel or applications. These registers can also trigger interrupts
21150793a61dSThomas Gleixner	  when a threshold number of events have passed - and can thus be
21160793a61dSThomas Gleixner	  used to profile the code that runs on that CPU.
21170793a61dSThomas Gleixner
211857c0c15bSIngo Molnar	  The Linux Performance Event subsystem provides an abstraction of
2119dd77038dSThadeu Lima de Souza Cascardo	  these software and hardware event capabilities, available via a
212057c0c15bSIngo Molnar	  system call and used by the "perf" utility in tools/perf/. It
21210793a61dSThomas Gleixner	  provides per task and per CPU counters, and it provides event
21220793a61dSThomas Gleixner	  capabilities on top of those.
21230793a61dSThomas Gleixner
21240793a61dSThomas Gleixner	  Say Y if unsure.
21250793a61dSThomas Gleixner
2126906010b2SPeter Zijlstraconfig DEBUG_PERF_USE_VMALLOC
2127906010b2SPeter Zijlstra	default n
2128906010b2SPeter Zijlstra	bool "Debug: use vmalloc to back perf mmap() buffers"
2129cb307113SMichael Ellerman	depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
2130906010b2SPeter Zijlstra	select PERF_USE_VMALLOC
2131906010b2SPeter Zijlstra	help
2132906010b2SPeter Zijlstra	  Use vmalloc memory to back perf mmap() buffers.
2133906010b2SPeter Zijlstra
2134906010b2SPeter Zijlstra	  Mostly useful for debugging the vmalloc code on platforms
2135906010b2SPeter Zijlstra	  that don't require it.
2136906010b2SPeter Zijlstra
2137906010b2SPeter Zijlstra	  Say N if unsure.
2138906010b2SPeter Zijlstra
21390793a61dSThomas Gleixnerendmenu
21400793a61dSThomas Gleixner
2141091f6e26SDavid Howellsconfig SYSTEM_DATA_VERIFICATION
2142091f6e26SDavid Howells	def_bool n
2143091f6e26SDavid Howells	select SYSTEM_TRUSTED_KEYRING
2144091f6e26SDavid Howells	select KEYS
2145091f6e26SDavid Howells	select CRYPTO
2146d43de6c7SDavid Howells	select CRYPTO_RSA
2147091f6e26SDavid Howells	select ASYMMETRIC_KEY_TYPE
2148091f6e26SDavid Howells	select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
2149091f6e26SDavid Howells	select ASN1
2150091f6e26SDavid Howells	select OID_REGISTRY
2151091f6e26SDavid Howells	select X509_CERTIFICATE_PARSER
2152091f6e26SDavid Howells	select PKCS7_MESSAGE_PARSER
215382c04ff8SPeter Foley	help
2154091f6e26SDavid Howells	  Provide PKCS#7 message verification using the contents of the system
2155091f6e26SDavid Howells	  trusted keyring to provide public keys.  This then can be used for
2156091f6e26SDavid Howells	  module verification, kexec image verification and firmware blob
2157091f6e26SDavid Howells	  verification.
215882c04ff8SPeter Foley
2159125e5645SMathieu Desnoyersconfig PROFILING
2160b309a294SRobert Richter	bool "Profiling support"
2161125e5645SMathieu Desnoyers	help
2162125e5645SMathieu Desnoyers	  Say Y here to enable the extended profiling support mechanisms used
2163f8408264SViresh Kumar	  by profilers.
2164125e5645SMathieu Desnoyers
21652f7ab126SMiguel Ojedaconfig RUST
21662f7ab126SMiguel Ojeda	bool "Rust support"
21672f7ab126SMiguel Ojeda	depends on HAVE_RUST
21682f7ab126SMiguel Ojeda	depends on RUST_IS_AVAILABLE
2169ac61506bSSami Tolvanen	select EXTENDED_MODVERSIONS if MODVERSIONS
2170ac61506bSSami Tolvanen	depends on !MODVERSIONS || GENDWARFKSYMS
2171f1385dc6SNeal Gompa	depends on !GCC_PLUGIN_RANDSTRUCT
21722f7ab126SMiguel Ojeda	depends on !RANDSTRUCT
21735daa0c35SMatthew Maurer	depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO)
217423ef9d43SKees Cook	depends on !CFI || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC
217523ef9d43SKees Cook	select CFI_ICALL_NORMALIZE_INTEGERS if CFI
2176af6017b6SMiguel Ojeda	depends on !CALL_PADDING || RUSTC_VERSION >= 108100
2177f64e2f3aSMatthew Maurer	depends on !KASAN_SW_TAGS
217893e34a0bSAlice Ryhl	depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300
21792f7ab126SMiguel Ojeda	help
21802f7ab126SMiguel Ojeda	  Enables Rust support in the kernel.
21812f7ab126SMiguel Ojeda
21822f7ab126SMiguel Ojeda	  This allows other Rust-related options, like drivers written in Rust,
21832f7ab126SMiguel Ojeda	  to be selected.
21842f7ab126SMiguel Ojeda
21852f7ab126SMiguel Ojeda	  It is also required to be able to load external kernel modules
21862f7ab126SMiguel Ojeda	  written in Rust.
21872f7ab126SMiguel Ojeda
21882f7ab126SMiguel Ojeda	  See Documentation/rust/ for more information.
21892f7ab126SMiguel Ojeda
21902f7ab126SMiguel Ojeda	  If unsure, say N.
21912f7ab126SMiguel Ojeda
21922f7ab126SMiguel Ojedaconfig RUSTC_VERSION_TEXT
21932f7ab126SMiguel Ojeda	string
21942f7ab126SMiguel Ojeda	depends on RUST
21955134a335SMiguel Ojeda	default "$(RUSTC_VERSION_TEXT)"
21965134a335SMiguel Ojeda	help
21975134a335SMiguel Ojeda	  See `CC_VERSION_TEXT`.
21982f7ab126SMiguel Ojeda
21992f7ab126SMiguel Ojedaconfig BINDGEN_VERSION_TEXT
22002f7ab126SMiguel Ojeda	string
22012f7ab126SMiguel Ojeda	depends on RUST
22029e98db17SMiguel Ojeda	# The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0
2203c23d1f7eSMiguel Ojeda	# (https://github.com/rust-lang/rust-bindgen/pull/2678) and 0.71.0
2204c23d1f7eSMiguel Ojeda	# (https://github.com/rust-lang/rust-bindgen/pull/3040). It can be removed
2205c23d1f7eSMiguel Ojeda	# when the minimum version is upgraded past the latter (0.69.1 and 0.71.1
2206c23d1f7eSMiguel Ojeda	# both fixed the issue).
2207aacf93e8SMasahiro Yamada	default "$(shell,$(BINDGEN) --version workaround-for-0.69.0 2>/dev/null)"
22082f7ab126SMiguel Ojeda
22095f87f112SIngo Molnar#
22105f87f112SIngo Molnar# Place an empty function call at each tracepoint site. Can be
22115f87f112SIngo Molnar# dynamically changed for a probe function.
22125f87f112SIngo Molnar#
221397e1c18eSMathieu Desnoyersconfig TRACEPOINTS
22145f87f112SIngo Molnar	bool
2215a363d27cSMathieu Desnoyers	select TASKS_TRACE_RCU
221697e1c18eSMathieu Desnoyers
221789cde455SEric DeVoldersource "kernel/Kconfig.kexec"
221889cde455SEric DeVolder
221948a1b232SPasha Tatashinsource "kernel/liveupdate/Kconfig"
222048a1b232SPasha Tatashin
22211da177e4SLinus Torvaldsendmenu		# General setup
22221da177e4SLinus Torvalds
22231572497cSChristoph Hellwigsource "arch/Kconfig"
22241572497cSChristoph Hellwig
2225ae81f9e3SChuck Ebbertconfig RT_MUTEXES
22266341e62bSChristoph Jaeger	bool
22271c6f9ec0SSebastian Andrzej Siewior	default y if PREEMPT_RT
2228ae81f9e3SChuck Ebbert
2229c8424e77SThiago Jung Bauermannconfig MODULE_SIG_FORMAT
2230c8424e77SThiago Jung Bauermann	def_bool n
2231c8424e77SThiago Jung Bauermann	select SYSTEM_DATA_VERIFICATION
2232c8424e77SThiago Jung Bauermann
223373b4fc92SChristophe Leroysource "kernel/module/Kconfig"
22346c9692e2SPeter Zijlstra
223598a79d6aSRusty Russellconfig INIT_ALL_POSSIBLE
223698a79d6aSRusty Russell	bool
223798a79d6aSRusty Russell	help
22385f054e31SRusty Russell	  Back when each arch used to define their own cpu_online_mask and
22395f054e31SRusty Russell	  cpu_possible_mask, some of them chose to initialize cpu_possible_mask
224098a79d6aSRusty Russell	  with all 1s, and others with all 0s.  When they were centralised,
224198a79d6aSRusty Russell	  it was better to provide this option than to break all the archs
2242692105b8SMatt LaPlante	  and have several arch maintainers pursuing me down dark alleys.
224398a79d6aSRusty Russell
22443a65dfe8SJens Axboesource "block/Kconfig"
2245e98c3202SAvi Kivity
2246e98c3202SAvi Kivityconfig PREEMPT_NOTIFIERS
2247e98c3202SAvi Kivity	bool
2248e260be67SPaul E. McKenney
224916295becSSteffen Klassertconfig PADATA
225016295becSSteffen Klassert	depends on SMP
225116295becSSteffen Klassert	bool
225216295becSSteffen Klassert
22534520c6a4SDavid Howellsconfig ASN1
22544520c6a4SDavid Howells	tristate
22554520c6a4SDavid Howells	help
22564520c6a4SDavid Howells	  Build a simple ASN.1 grammar compiler that produces a bytecode output
22574520c6a4SDavid Howells	  that can be interpreted by the ASN.1 stream decoder and used to
22584520c6a4SDavid Howells	  inform it as to what tags are to be expected in a stream and what
22594520c6a4SDavid Howells	  functions to call on what tags.
22604520c6a4SDavid Howells
22616beb0009SThomas Gleixnersource "kernel/Kconfig.locks"
2262e61938a9SMathieu Desnoyers
22630ebeea8cSDaniel Borkmannconfig ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
22640ebeea8cSDaniel Borkmann	bool
22650ebeea8cSDaniel Borkmann
22664ff4c745SAndrea Parriconfig ARCH_HAS_PREPARE_SYNC_CORE_CMD
22674ff4c745SAndrea Parri	bool
22684ff4c745SAndrea Parri
2269e61938a9SMathieu Desnoyersconfig ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
2270e61938a9SMathieu Desnoyers	bool
22711bd21c6cSDominik Brodowski
22721bd21c6cSDominik Brodowski# It may be useful for an architecture to override the definitions of the
22737303e30eSDominik Brodowski# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h>
22747303e30eSDominik Brodowski# and the COMPAT_ variants in <linux/compat.h>, in particular to use a
22757303e30eSDominik Brodowski# different calling convention for syscalls. They can also override the
22767303e30eSDominik Brodowski# macros for not-implemented syscalls in kernel/sys_ni.c and
22777303e30eSDominik Brodowski# kernel/time/posix-stubs.c. All these overrides need to be available in
22787303e30eSDominik Brodowski# <asm/syscall_wrapper.h>.
22791bd21c6cSDominik Brodowskiconfig ARCH_HAS_SYSCALL_WRAPPER
22801bd21c6cSDominik Brodowski	def_bool n
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