1 # SPDX-License-Identifier: GPL-2.0-only 1 # SPDX-License-Identifier: GPL-2.0-only
2 config CC_VERSION_TEXT 2 config CC_VERSION_TEXT
3 string 3 string
4 default "$(CC_VERSION_TEXT)" 4 default "$(CC_VERSION_TEXT)"
5 help 5 help
6 This is used in unclear ways: 6 This is used in unclear ways:
7 7
8 - Re-run Kconfig when the compiler i 8 - Re-run Kconfig when the compiler is updated
9 The 'default' property references 9 The 'default' property references the environment variable,
10 CC_VERSION_TEXT so it is recorded 10 CC_VERSION_TEXT so it is recorded in include/config/auto.conf.cmd.
11 When the compiler is updated, Kcon 11 When the compiler is updated, Kconfig will be invoked.
12 12
13 - Ensure full rebuild when the compi 13 - Ensure full rebuild when the compiler is updated
14 include/linux/compiler-version.h c 14 include/linux/compiler-version.h contains this option in the comment
15 line so fixdep adds include/config 15 line so fixdep adds include/config/CC_VERSION_TEXT into the
16 auto-generated dependency. When th 16 auto-generated dependency. When the compiler is updated, syncconfig
17 will touch it and then every file 17 will touch it and then every file will be rebuilt.
18 18
19 config CC_IS_GCC 19 config CC_IS_GCC
20 def_bool $(success,test "$(cc-name)" = 20 def_bool $(success,test "$(cc-name)" = GCC)
21 21
22 config GCC_VERSION 22 config GCC_VERSION
23 int 23 int
24 default $(cc-version) if CC_IS_GCC 24 default $(cc-version) if CC_IS_GCC
25 default 0 25 default 0
26 26
27 config CC_IS_CLANG 27 config CC_IS_CLANG
28 def_bool $(success,test "$(cc-name)" = 28 def_bool $(success,test "$(cc-name)" = Clang)
29 29
30 config CLANG_VERSION 30 config CLANG_VERSION
31 int 31 int
32 default $(cc-version) if CC_IS_CLANG 32 default $(cc-version) if CC_IS_CLANG
33 default 0 33 default 0
34 34
35 config AS_IS_GNU 35 config AS_IS_GNU
36 def_bool $(success,test "$(as-name)" = 36 def_bool $(success,test "$(as-name)" = GNU)
37 37
38 config AS_IS_LLVM 38 config AS_IS_LLVM
39 def_bool $(success,test "$(as-name)" = 39 def_bool $(success,test "$(as-name)" = LLVM)
40 40
41 config AS_VERSION 41 config AS_VERSION
42 int 42 int
43 # Use clang version if this is the int 43 # Use clang version if this is the integrated assembler
44 default CLANG_VERSION if AS_IS_LLVM 44 default CLANG_VERSION if AS_IS_LLVM
45 default $(as-version) 45 default $(as-version)
46 46
47 config LD_IS_BFD 47 config LD_IS_BFD
48 def_bool $(success,test "$(ld-name)" = 48 def_bool $(success,test "$(ld-name)" = BFD)
49 49
50 config LD_VERSION 50 config LD_VERSION
51 int 51 int
52 default $(ld-version) if LD_IS_BFD 52 default $(ld-version) if LD_IS_BFD
53 default 0 53 default 0
54 54
55 config LD_IS_LLD 55 config LD_IS_LLD
56 def_bool $(success,test "$(ld-name)" = 56 def_bool $(success,test "$(ld-name)" = LLD)
57 57
58 config LLD_VERSION 58 config LLD_VERSION
59 int 59 int
60 default $(ld-version) if LD_IS_LLD 60 default $(ld-version) if LD_IS_LLD
61 default 0 61 default 0
62 62
63 config RUSTC_VERSION <<
64 int <<
65 default $(rustc-version) <<
66 help <<
67 It does not depend on `RUST` since t <<
68 in a `depends on`. <<
69 <<
70 config RUST_IS_AVAILABLE 63 config RUST_IS_AVAILABLE
71 def_bool $(success,$(srctree)/scripts/ 64 def_bool $(success,$(srctree)/scripts/rust_is_available.sh)
72 help 65 help
73 This shows whether a suitable Rust t 66 This shows whether a suitable Rust toolchain is available (found).
74 67
75 Please see Documentation/rust/quick- 68 Please see Documentation/rust/quick-start.rst for instructions on how
76 to satisfy the build requirements of 69 to satisfy the build requirements of Rust support.
77 70
78 In particular, the Makefile target ' 71 In particular, the Makefile target 'rustavailable' is useful to check
79 why the Rust toolchain is not being 72 why the Rust toolchain is not being detected.
80 73
81 config RUSTC_LLVM_VERSION <<
82 int <<
83 default $(rustc-llvm-version) <<
84 <<
85 config CC_CAN_LINK 74 config CC_CAN_LINK
86 bool 75 bool
87 default $(success,$(srctree)/scripts/c 76 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag)) if 64BIT
88 default $(success,$(srctree)/scripts/c 77 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m32-flag))
89 78
90 config CC_CAN_LINK_STATIC 79 config CC_CAN_LINK_STATIC
91 bool 80 bool
92 default $(success,$(srctree)/scripts/c 81 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag) -static) if 64BIT
93 default $(success,$(srctree)/scripts/c 82 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m32-flag) -static)
94 83
95 # Fixed in GCC 14, 13.3, 12.4 and 11.5 84 # Fixed in GCC 14, 13.3, 12.4 and 11.5
96 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id 85 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113921
97 config GCC_ASM_GOTO_OUTPUT_BROKEN 86 config GCC_ASM_GOTO_OUTPUT_BROKEN
98 bool 87 bool
99 depends on CC_IS_GCC 88 depends on CC_IS_GCC
100 default y if GCC_VERSION < 110500 89 default y if GCC_VERSION < 110500
101 default y if GCC_VERSION >= 120000 && 90 default y if GCC_VERSION >= 120000 && GCC_VERSION < 120400
102 default y if GCC_VERSION >= 130000 && 91 default y if GCC_VERSION >= 130000 && GCC_VERSION < 130300
103 92
104 config CC_HAS_ASM_GOTO_OUTPUT 93 config CC_HAS_ASM_GOTO_OUTPUT
105 def_bool y 94 def_bool y
106 depends on !GCC_ASM_GOTO_OUTPUT_BROKEN 95 depends on !GCC_ASM_GOTO_OUTPUT_BROKEN
107 depends on $(success,echo 'int foo(int 96 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)
108 97
109 config CC_HAS_ASM_GOTO_TIED_OUTPUT 98 config CC_HAS_ASM_GOTO_TIED_OUTPUT
110 depends on CC_HAS_ASM_GOTO_OUTPUT 99 depends on CC_HAS_ASM_GOTO_OUTPUT
111 # Detect buggy gcc and clang, fixed in 100 # Detect buggy gcc and clang, fixed in gcc-11 clang-14.
112 def_bool $(success,echo 'int foo(int * 101 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)
113 102
114 config TOOLS_SUPPORT_RELR 103 config TOOLS_SUPPORT_RELR
115 def_bool $(success,env "CC=$(CC)" "LD= 104 def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh)
116 105
117 config CC_HAS_ASM_INLINE 106 config CC_HAS_ASM_INLINE
118 def_bool $(success,echo 'void foo(void 107 def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null)
119 108
120 config CC_HAS_NO_PROFILE_FN_ATTR 109 config CC_HAS_NO_PROFILE_FN_ATTR
121 def_bool $(success,echo '__attribute__ 110 def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror)
122 111
123 config PAHOLE_VERSION 112 config PAHOLE_VERSION
124 int 113 int
125 default $(shell,$(srctree)/scripts/pah 114 default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE))
126 115
127 config CONSTRUCTORS 116 config CONSTRUCTORS
128 bool 117 bool
129 118
130 config IRQ_WORK 119 config IRQ_WORK
131 def_bool y if SMP 120 def_bool y if SMP
132 121
133 config BUILDTIME_TABLE_SORT 122 config BUILDTIME_TABLE_SORT
134 bool 123 bool
135 124
136 config THREAD_INFO_IN_TASK 125 config THREAD_INFO_IN_TASK
137 bool 126 bool
138 help 127 help
139 Select this to move thread_info off 128 Select this to move thread_info off the stack into task_struct. To
140 make this work, an arch will need to 129 make this work, an arch will need to remove all thread_info fields
141 except flags and fix any runtime bug 130 except flags and fix any runtime bugs.
142 131
143 One subtle change that will be neede 132 One subtle change that will be needed is to use try_get_task_stack()
144 and put_task_stack() in save_thread_ 133 and put_task_stack() in save_thread_stack_tsk() and get_wchan().
145 134
146 menu "General setup" 135 menu "General setup"
147 136
148 config BROKEN 137 config BROKEN
149 bool 138 bool
150 139
151 config BROKEN_ON_SMP 140 config BROKEN_ON_SMP
152 bool 141 bool
153 depends on BROKEN || !SMP 142 depends on BROKEN || !SMP
154 default y 143 default y
155 144
156 config INIT_ENV_ARG_LIMIT 145 config INIT_ENV_ARG_LIMIT
157 int 146 int
158 default 32 if !UML 147 default 32 if !UML
159 default 128 if UML 148 default 128 if UML
160 help 149 help
161 Maximum of each of the number of arg 150 Maximum of each of the number of arguments and environment
162 variables passed to init from the ke 151 variables passed to init from the kernel command line.
163 152
164 config COMPILE_TEST 153 config COMPILE_TEST
165 bool "Compile also drivers which will 154 bool "Compile also drivers which will not load"
166 depends on HAS_IOMEM 155 depends on HAS_IOMEM
167 help 156 help
168 Some drivers can be compiled on a di 157 Some drivers can be compiled on a different platform than they are
169 intended to be run on. Despite they 158 intended to be run on. Despite they cannot be loaded there (or even
170 when they load they cannot be used d 159 when they load they cannot be used due to missing HW support),
171 developers still, opposing to distri 160 developers still, opposing to distributors, might want to build such
172 drivers to compile-test them. 161 drivers to compile-test them.
173 162
174 If you are a developer and want to b 163 If you are a developer and want to build everything available, say Y
175 here. If you are a user/distributor, 164 here. If you are a user/distributor, say N here to exclude useless
176 drivers to be distributed. 165 drivers to be distributed.
177 166
178 config WERROR 167 config WERROR
179 bool "Compile the kernel with warnings 168 bool "Compile the kernel with warnings as errors"
180 default COMPILE_TEST 169 default COMPILE_TEST
181 help 170 help
182 A kernel build should not cause any 171 A kernel build should not cause any compiler warnings, and this
183 enables the '-Werror' (for C) and '- 172 enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags
184 to enforce that rule by default. Cer 173 to enforce that rule by default. Certain warnings from other tools
185 such as the linker may be upgraded t 174 such as the linker may be upgraded to errors with this option as
186 well. 175 well.
187 176
188 However, if you have a new (or very 177 However, if you have a new (or very old) compiler or linker with odd
189 and unusual warnings, or you have so 178 and unusual warnings, or you have some architecture with problems,
190 you may need to disable this config 179 you may need to disable this config option in order to
191 successfully build the kernel. 180 successfully build the kernel.
192 181
193 If in doubt, say Y. 182 If in doubt, say Y.
194 183
195 config UAPI_HEADER_TEST 184 config UAPI_HEADER_TEST
196 bool "Compile test UAPI headers" 185 bool "Compile test UAPI headers"
197 depends on HEADERS_INSTALL && CC_CAN_L 186 depends on HEADERS_INSTALL && CC_CAN_LINK
198 help 187 help
199 Compile test headers exported to use 188 Compile test headers exported to user-space to ensure they are
200 self-contained, i.e. compilable as s 189 self-contained, i.e. compilable as standalone units.
201 190
202 If you are a developer or tester and 191 If you are a developer or tester and want to ensure the exported
203 headers are self-contained, say Y he 192 headers are self-contained, say Y here. Otherwise, choose N.
204 193
205 config LOCALVERSION 194 config LOCALVERSION
206 string "Local version - append to kern 195 string "Local version - append to kernel release"
207 help 196 help
208 Append an extra string to the end of 197 Append an extra string to the end of your kernel version.
209 This will show up when you type unam 198 This will show up when you type uname, for example.
210 The string you set here will be appe 199 The string you set here will be appended after the contents of
211 any files with a filename matching l 200 any files with a filename matching localversion* in your
212 object and source tree, in that orde 201 object and source tree, in that order. Your total string can
213 be a maximum of 64 characters. 202 be a maximum of 64 characters.
214 203
215 config LOCALVERSION_AUTO 204 config LOCALVERSION_AUTO
216 bool "Automatically append version inf 205 bool "Automatically append version information to the version string"
217 default y 206 default y
218 depends on !COMPILE_TEST 207 depends on !COMPILE_TEST
219 help 208 help
220 This will try to automatically deter 209 This will try to automatically determine if the current tree is a
221 release tree by looking for git tags 210 release tree by looking for git tags that belong to the current
222 top of tree revision. 211 top of tree revision.
223 212
224 A string of the format -gxxxxxxxx wi 213 A string of the format -gxxxxxxxx will be added to the localversion
225 if a git-based tree is found. The s 214 if a git-based tree is found. The string generated by this will be
226 appended after any matching localver 215 appended after any matching localversion* files, and after the value
227 set in CONFIG_LOCALVERSION. 216 set in CONFIG_LOCALVERSION.
228 217
229 (The actual string used here is the 218 (The actual string used here is the first 12 characters produced
230 by running the command: 219 by running the command:
231 220
232 $ git rev-parse --verify HEAD 221 $ git rev-parse --verify HEAD
233 222
234 which is done within the script "scr 223 which is done within the script "scripts/setlocalversion".)
235 224
236 config BUILD_SALT 225 config BUILD_SALT
237 string "Build ID Salt" 226 string "Build ID Salt"
238 default "" 227 default ""
239 help 228 help
240 The build ID is used to link binarie 229 The build ID is used to link binaries and their debug info. Setting
241 this option will use the value in th 230 this option will use the value in the calculation of the build id.
242 This is mostly useful for distributi 231 This is mostly useful for distributions which want to ensure the
243 build is unique between builds. It's 232 build is unique between builds. It's safe to leave the default.
244 233
245 config HAVE_KERNEL_GZIP 234 config HAVE_KERNEL_GZIP
246 bool 235 bool
247 236
248 config HAVE_KERNEL_BZIP2 237 config HAVE_KERNEL_BZIP2
249 bool 238 bool
250 239
251 config HAVE_KERNEL_LZMA 240 config HAVE_KERNEL_LZMA
252 bool 241 bool
253 242
254 config HAVE_KERNEL_XZ 243 config HAVE_KERNEL_XZ
255 bool 244 bool
256 245
257 config HAVE_KERNEL_LZO 246 config HAVE_KERNEL_LZO
258 bool 247 bool
259 248
260 config HAVE_KERNEL_LZ4 249 config HAVE_KERNEL_LZ4
261 bool 250 bool
262 251
263 config HAVE_KERNEL_ZSTD 252 config HAVE_KERNEL_ZSTD
264 bool 253 bool
265 254
266 config HAVE_KERNEL_UNCOMPRESSED 255 config HAVE_KERNEL_UNCOMPRESSED
267 bool 256 bool
268 257
269 choice 258 choice
270 prompt "Kernel compression mode" 259 prompt "Kernel compression mode"
271 default KERNEL_GZIP 260 default KERNEL_GZIP
272 depends on HAVE_KERNEL_GZIP || HAVE_KE 261 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
273 help 262 help
274 The linux kernel is a kind of self-e 263 The linux kernel is a kind of self-extracting executable.
275 Several compression algorithms are a 264 Several compression algorithms are available, which differ
276 in efficiency, compression and decom 265 in efficiency, compression and decompression speed.
277 Compression speed is only relevant w 266 Compression speed is only relevant when building a kernel.
278 Decompression speed is relevant at e 267 Decompression speed is relevant at each boot.
279 268
280 If you have any problems with bzip2 269 If you have any problems with bzip2 or lzma compressed
281 kernels, mail me (Alain Knaff) <alain 270 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
282 version of this functionality (bzip2 271 version of this functionality (bzip2 only), for 2.4, was
283 supplied by Christian Ludwig) 272 supplied by Christian Ludwig)
284 273
285 High compression options are mostly 274 High compression options are mostly useful for users, who
286 are low on disk space (embedded syst 275 are low on disk space (embedded systems), but for whom ram
287 size matters less. 276 size matters less.
288 277
289 If in doubt, select 'gzip' 278 If in doubt, select 'gzip'
290 279
291 config KERNEL_GZIP 280 config KERNEL_GZIP
292 bool "Gzip" 281 bool "Gzip"
293 depends on HAVE_KERNEL_GZIP 282 depends on HAVE_KERNEL_GZIP
294 help 283 help
295 The old and tried gzip compression. 284 The old and tried gzip compression. It provides a good balance
296 between compression ratio and decomp 285 between compression ratio and decompression speed.
297 286
298 config KERNEL_BZIP2 287 config KERNEL_BZIP2
299 bool "Bzip2" 288 bool "Bzip2"
300 depends on HAVE_KERNEL_BZIP2 289 depends on HAVE_KERNEL_BZIP2
301 help 290 help
302 Its compression ratio and speed is i 291 Its compression ratio and speed is intermediate.
303 Decompression speed is slowest among 292 Decompression speed is slowest among the choices. The kernel
304 size is about 10% smaller with bzip2 293 size is about 10% smaller with bzip2, in comparison to gzip.
305 Bzip2 uses a large amount of memory. 294 Bzip2 uses a large amount of memory. For modern kernels you
306 will need at least 8MB RAM or more f 295 will need at least 8MB RAM or more for booting.
307 296
308 config KERNEL_LZMA 297 config KERNEL_LZMA
309 bool "LZMA" 298 bool "LZMA"
310 depends on HAVE_KERNEL_LZMA 299 depends on HAVE_KERNEL_LZMA
311 help 300 help
312 This compression algorithm's ratio i 301 This compression algorithm's ratio is best. Decompression speed
313 is between gzip and bzip2. Compress 302 is between gzip and bzip2. Compression is slowest.
314 The kernel size is about 33% smaller 303 The kernel size is about 33% smaller with LZMA in comparison to gzip.
315 304
316 config KERNEL_XZ 305 config KERNEL_XZ
317 bool "XZ" 306 bool "XZ"
318 depends on HAVE_KERNEL_XZ 307 depends on HAVE_KERNEL_XZ
319 help 308 help
320 XZ uses the LZMA2 algorithm and inst 309 XZ uses the LZMA2 algorithm and instruction set specific
321 BCJ filters which can improve compre 310 BCJ filters which can improve compression ratio of executable
322 code. The size of the kernel is abou 311 code. The size of the kernel is about 30% smaller with XZ in
323 comparison to gzip. On architectures 312 comparison to gzip. On architectures for which there is a BCJ
324 filter (i386, x86_64, ARM, ARM64, RI !! 313 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
325 and SPARC), XZ will create a few per !! 314 will create a few percent smaller kernel than plain LZMA.
326 plain LZMA. <<
327 315
328 The speed is about the same as with 316 The speed is about the same as with LZMA: The decompression
329 speed of XZ is better than that of b 317 speed of XZ is better than that of bzip2 but worse than gzip
330 and LZO. Compression is slow. 318 and LZO. Compression is slow.
331 319
332 config KERNEL_LZO 320 config KERNEL_LZO
333 bool "LZO" 321 bool "LZO"
334 depends on HAVE_KERNEL_LZO 322 depends on HAVE_KERNEL_LZO
335 help 323 help
336 Its compression ratio is the poorest 324 Its compression ratio is the poorest among the choices. The kernel
337 size is about 10% bigger than gzip; 325 size is about 10% bigger than gzip; however its speed
338 (both compression and decompression) 326 (both compression and decompression) is the fastest.
339 327
340 config KERNEL_LZ4 328 config KERNEL_LZ4
341 bool "LZ4" 329 bool "LZ4"
342 depends on HAVE_KERNEL_LZ4 330 depends on HAVE_KERNEL_LZ4
343 help 331 help
344 LZ4 is an LZ77-type compressor with 332 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
345 A preliminary version of LZ4 de/comp 333 A preliminary version of LZ4 de/compression tool is available at
346 <https://code.google.com/p/lz4/>. 334 <https://code.google.com/p/lz4/>.
347 335
348 Its compression ratio is worse than 336 Its compression ratio is worse than LZO. The size of the kernel
349 is about 8% bigger than LZO. But the 337 is about 8% bigger than LZO. But the decompression speed is
350 faster than LZO. 338 faster than LZO.
351 339
352 config KERNEL_ZSTD 340 config KERNEL_ZSTD
353 bool "ZSTD" 341 bool "ZSTD"
354 depends on HAVE_KERNEL_ZSTD 342 depends on HAVE_KERNEL_ZSTD
355 help 343 help
356 ZSTD is a compression algorithm targ 344 ZSTD is a compression algorithm targeting intermediate compression
357 with fast decompression speed. It wi 345 with fast decompression speed. It will compress better than GZIP and
358 decompress around the same speed as 346 decompress around the same speed as LZO, but slower than LZ4. You
359 will need at least 192 KB RAM or mor 347 will need at least 192 KB RAM or more for booting. The zstd command
360 line tool is required for compressio 348 line tool is required for compression.
361 349
362 config KERNEL_UNCOMPRESSED 350 config KERNEL_UNCOMPRESSED
363 bool "None" 351 bool "None"
364 depends on HAVE_KERNEL_UNCOMPRESSED 352 depends on HAVE_KERNEL_UNCOMPRESSED
365 help 353 help
366 Produce uncompressed kernel image. T 354 Produce uncompressed kernel image. This option is usually not what
367 you want. It is useful for debugging 355 you want. It is useful for debugging the kernel in slow simulation
368 environments, where decompressing an 356 environments, where decompressing and moving the kernel is awfully
369 slow. This option allows early boot 357 slow. This option allows early boot code to skip the decompressor
370 and jump right at uncompressed kerne 358 and jump right at uncompressed kernel image.
371 359
372 endchoice 360 endchoice
373 361
374 config DEFAULT_INIT 362 config DEFAULT_INIT
375 string "Default init path" 363 string "Default init path"
376 default "" 364 default ""
377 help 365 help
378 This option determines the default i 366 This option determines the default init for the system if no init=
379 option is passed on the kernel comma 367 option is passed on the kernel command line. If the requested path is
380 not present, we will still then move 368 not present, we will still then move on to attempting further
381 locations (e.g. /sbin/init, etc). If 369 locations (e.g. /sbin/init, etc). If this is empty, we will just use
382 the fallback list when init= is not 370 the fallback list when init= is not passed.
383 371
384 config DEFAULT_HOSTNAME 372 config DEFAULT_HOSTNAME
385 string "Default hostname" 373 string "Default hostname"
386 default "(none)" 374 default "(none)"
387 help 375 help
388 This option determines the default s 376 This option determines the default system hostname before userspace
389 calls sethostname(2). The kernel tra 377 calls sethostname(2). The kernel traditionally uses "(none)" here,
390 but you may wish to use a different 378 but you may wish to use a different default here to make a minimal
391 system more usable with less configu 379 system more usable with less configuration.
392 380
393 config SYSVIPC 381 config SYSVIPC
394 bool "System V IPC" 382 bool "System V IPC"
395 help 383 help
396 Inter Process Communication is a sui 384 Inter Process Communication is a suite of library functions and
397 system calls which let processes (ru 385 system calls which let processes (running programs) synchronize and
398 exchange information. It is generall 386 exchange information. It is generally considered to be a good thing,
399 and some programs won't run unless y 387 and some programs won't run unless you say Y here. In particular, if
400 you want to run the DOS emulator dos 388 you want to run the DOS emulator dosemu under Linux (read the
401 DOSEMU-HOWTO, available from <http:/ 389 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
402 you'll need to say Y here. 390 you'll need to say Y here.
403 391
404 You can find documentation about IPC 392 You can find documentation about IPC with "info ipc" and also in
405 section 6.4 of the Linux Programmer' 393 section 6.4 of the Linux Programmer's Guide, available from
406 <http://www.tldp.org/guides.html>. 394 <http://www.tldp.org/guides.html>.
407 395
408 config SYSVIPC_SYSCTL 396 config SYSVIPC_SYSCTL
409 bool 397 bool
410 depends on SYSVIPC 398 depends on SYSVIPC
411 depends on SYSCTL 399 depends on SYSCTL
412 default y 400 default y
413 401
414 config SYSVIPC_COMPAT 402 config SYSVIPC_COMPAT
415 def_bool y 403 def_bool y
416 depends on COMPAT && SYSVIPC 404 depends on COMPAT && SYSVIPC
417 405
418 config POSIX_MQUEUE 406 config POSIX_MQUEUE
419 bool "POSIX Message Queues" 407 bool "POSIX Message Queues"
420 depends on NET 408 depends on NET
421 help 409 help
422 POSIX variant of message queues is a 410 POSIX variant of message queues is a part of IPC. In POSIX message
423 queues every message has a priority 411 queues every message has a priority which decides about succession
424 of receiving it by a process. If you 412 of receiving it by a process. If you want to compile and run
425 programs written e.g. for Solaris wi 413 programs written e.g. for Solaris with use of its POSIX message
426 queues (functions mq_*) say Y here. 414 queues (functions mq_*) say Y here.
427 415
428 POSIX message queues are visible as 416 POSIX message queues are visible as a filesystem called 'mqueue'
429 and can be mounted somewhere if you 417 and can be mounted somewhere if you want to do filesystem
430 operations on message queues. 418 operations on message queues.
431 419
432 If unsure, say Y. 420 If unsure, say Y.
433 421
434 config POSIX_MQUEUE_SYSCTL 422 config POSIX_MQUEUE_SYSCTL
435 bool 423 bool
436 depends on POSIX_MQUEUE 424 depends on POSIX_MQUEUE
437 depends on SYSCTL 425 depends on SYSCTL
438 default y 426 default y
439 427
440 config WATCH_QUEUE 428 config WATCH_QUEUE
441 bool "General notification queue" 429 bool "General notification queue"
442 default n 430 default n
443 help 431 help
444 432
445 This is a general notification queue 433 This is a general notification queue for the kernel to pass events to
446 userspace by splicing them into pipe 434 userspace by splicing them into pipes. It can be used in conjunction
447 with watches for key/keyring change 435 with watches for key/keyring change notifications and device
448 notifications. 436 notifications.
449 437
450 See Documentation/core-api/watch_que 438 See Documentation/core-api/watch_queue.rst
451 439
452 config CROSS_MEMORY_ATTACH 440 config CROSS_MEMORY_ATTACH
453 bool "Enable process_vm_readv/writev s 441 bool "Enable process_vm_readv/writev syscalls"
454 depends on MMU 442 depends on MMU
455 default y 443 default y
456 help 444 help
457 Enabling this option adds the system 445 Enabling this option adds the system calls process_vm_readv and
458 process_vm_writev which allow a proc 446 process_vm_writev which allow a process with the correct privileges
459 to directly read from or write to an 447 to directly read from or write to another process' address space.
460 See the man page for more details. 448 See the man page for more details.
461 449
462 config USELIB 450 config USELIB
463 bool "uselib syscall (for libc5 and ea 451 bool "uselib syscall (for libc5 and earlier)"
464 default ALPHA || M68K || SPARC 452 default ALPHA || M68K || SPARC
465 help 453 help
466 This option enables the uselib sysca 454 This option enables the uselib syscall, a system call used in the
467 dynamic linker from libc5 and earlie 455 dynamic linker from libc5 and earlier. glibc does not use this
468 system call. If you intend to run p 456 system call. If you intend to run programs built on libc5 or
469 earlier, you may need to enable this 457 earlier, you may need to enable this syscall. Current systems
470 running glibc can safely disable thi 458 running glibc can safely disable this.
471 459
472 config AUDIT 460 config AUDIT
473 bool "Auditing support" 461 bool "Auditing support"
474 depends on NET 462 depends on NET
475 help 463 help
476 Enable auditing infrastructure that 464 Enable auditing infrastructure that can be used with another
477 kernel subsystem, such as SELinux (w 465 kernel subsystem, such as SELinux (which requires this for
478 logging of avc messages output). Sy 466 logging of avc messages output). System call auditing is included
479 on architectures which support it. 467 on architectures which support it.
480 468
481 config HAVE_ARCH_AUDITSYSCALL 469 config HAVE_ARCH_AUDITSYSCALL
482 bool 470 bool
483 471
484 config AUDITSYSCALL 472 config AUDITSYSCALL
485 def_bool y 473 def_bool y
486 depends on AUDIT && HAVE_ARCH_AUDITSYS 474 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
487 select FSNOTIFY 475 select FSNOTIFY
488 476
489 source "kernel/irq/Kconfig" 477 source "kernel/irq/Kconfig"
490 source "kernel/time/Kconfig" 478 source "kernel/time/Kconfig"
491 source "kernel/bpf/Kconfig" 479 source "kernel/bpf/Kconfig"
492 source "kernel/Kconfig.preempt" 480 source "kernel/Kconfig.preempt"
493 481
494 menu "CPU/Task time and stats accounting" 482 menu "CPU/Task time and stats accounting"
495 483
496 config VIRT_CPU_ACCOUNTING 484 config VIRT_CPU_ACCOUNTING
497 bool 485 bool
498 486
499 choice 487 choice
500 prompt "Cputime accounting" 488 prompt "Cputime accounting"
501 default TICK_CPU_ACCOUNTING 489 default TICK_CPU_ACCOUNTING
502 490
503 # Kind of a stub config for the pure tick base 491 # Kind of a stub config for the pure tick based cputime accounting
504 config TICK_CPU_ACCOUNTING 492 config TICK_CPU_ACCOUNTING
505 bool "Simple tick based cputime accoun 493 bool "Simple tick based cputime accounting"
506 depends on !S390 && !NO_HZ_FULL 494 depends on !S390 && !NO_HZ_FULL
507 help 495 help
508 This is the basic tick based cputime 496 This is the basic tick based cputime accounting that maintains
509 statistics about user, system and id 497 statistics about user, system and idle time spent on per jiffies
510 granularity. 498 granularity.
511 499
512 If unsure, say Y. 500 If unsure, say Y.
513 501
514 config VIRT_CPU_ACCOUNTING_NATIVE 502 config VIRT_CPU_ACCOUNTING_NATIVE
515 bool "Deterministic task and CPU time 503 bool "Deterministic task and CPU time accounting"
516 depends on HAVE_VIRT_CPU_ACCOUNTING && 504 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
517 select VIRT_CPU_ACCOUNTING 505 select VIRT_CPU_ACCOUNTING
518 help 506 help
519 Select this option to enable more ac 507 Select this option to enable more accurate task and CPU time
520 accounting. This is done by reading 508 accounting. This is done by reading a CPU counter on each
521 kernel entry and exit and on transit 509 kernel entry and exit and on transitions within the kernel
522 between system, softirq and hardirq 510 between system, softirq and hardirq state, so there is a
523 small performance impact. In the ca 511 small performance impact. In the case of s390 or IBM POWER > 5,
524 this also enables accounting of stol 512 this also enables accounting of stolen time on logically-partitioned
525 systems. 513 systems.
526 514
527 config VIRT_CPU_ACCOUNTING_GEN 515 config VIRT_CPU_ACCOUNTING_GEN
528 bool "Full dynticks CPU time accountin 516 bool "Full dynticks CPU time accounting"
529 depends on HAVE_CONTEXT_TRACKING_USER 517 depends on HAVE_CONTEXT_TRACKING_USER
530 depends on HAVE_VIRT_CPU_ACCOUNTING_GE 518 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
531 depends on GENERIC_CLOCKEVENTS 519 depends on GENERIC_CLOCKEVENTS
532 select VIRT_CPU_ACCOUNTING 520 select VIRT_CPU_ACCOUNTING
533 select CONTEXT_TRACKING_USER 521 select CONTEXT_TRACKING_USER
534 help 522 help
535 Select this option to enable task an 523 Select this option to enable task and CPU time accounting on full
536 dynticks systems. This accounting is 524 dynticks systems. This accounting is implemented by watching every
537 kernel-user boundaries using the con 525 kernel-user boundaries using the context tracking subsystem.
538 The accounting is thus performed at 526 The accounting is thus performed at the expense of some significant
539 overhead. 527 overhead.
540 528
541 For now this is only useful if you a 529 For now this is only useful if you are working on the full
542 dynticks subsystem development. 530 dynticks subsystem development.
543 531
544 If unsure, say N. 532 If unsure, say N.
545 533
546 endchoice 534 endchoice
547 535
548 config IRQ_TIME_ACCOUNTING 536 config IRQ_TIME_ACCOUNTING
549 bool "Fine granularity task level IRQ 537 bool "Fine granularity task level IRQ time accounting"
550 depends on HAVE_IRQ_TIME_ACCOUNTING && 538 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
551 help 539 help
552 Select this option to enable fine gr 540 Select this option to enable fine granularity task irq time
553 accounting. This is done by reading 541 accounting. This is done by reading a timestamp on each
554 transitions between softirq and hard 542 transitions between softirq and hardirq state, so there can be a
555 small performance impact. 543 small performance impact.
556 544
557 If in doubt, say N here. 545 If in doubt, say N here.
558 546
559 config HAVE_SCHED_AVG_IRQ 547 config HAVE_SCHED_AVG_IRQ
560 def_bool y 548 def_bool y
561 depends on IRQ_TIME_ACCOUNTING || PARA 549 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING
562 depends on SMP 550 depends on SMP
563 551
564 config SCHED_HW_PRESSURE 552 config SCHED_HW_PRESSURE
565 bool 553 bool
566 default y if ARM && ARM_CPU_TOPOLOGY 554 default y if ARM && ARM_CPU_TOPOLOGY
567 default y if ARM64 555 default y if ARM64
568 depends on SMP 556 depends on SMP
569 depends on CPU_FREQ_THERMAL 557 depends on CPU_FREQ_THERMAL
570 help 558 help
571 Select this option to enable HW pres 559 Select this option to enable HW pressure accounting in the
572 scheduler. HW pressure is the value 560 scheduler. HW pressure is the value conveyed to the scheduler
573 that reflects the reduction in CPU c 561 that reflects the reduction in CPU compute capacity resulted from
574 HW throttling. HW throttling occurs 562 HW throttling. HW throttling occurs when the performance of
575 a CPU is capped due to high operatin 563 a CPU is capped due to high operating temperatures as an example.
576 564
577 If selected, the scheduler will be a 565 If selected, the scheduler will be able to balance tasks accordingly,
578 i.e. put less load on throttled CPUs 566 i.e. put less load on throttled CPUs than on non/less throttled ones.
579 567
580 This requires the architecture to im 568 This requires the architecture to implement
581 arch_update_hw_pressure() and arch_s 569 arch_update_hw_pressure() and arch_scale_thermal_pressure().
582 570
583 config BSD_PROCESS_ACCT 571 config BSD_PROCESS_ACCT
584 bool "BSD Process Accounting" 572 bool "BSD Process Accounting"
585 depends on MULTIUSER 573 depends on MULTIUSER
586 help 574 help
587 If you say Y here, a user level prog 575 If you say Y here, a user level program will be able to instruct the
588 kernel (via a special system call) t 576 kernel (via a special system call) to write process accounting
589 information to a file: whenever a pr 577 information to a file: whenever a process exits, information about
590 that process will be appended to the 578 that process will be appended to the file by the kernel. The
591 information includes things such as 579 information includes things such as creation time, owning user,
592 command name, memory usage, controll 580 command name, memory usage, controlling terminal etc. (the complete
593 list is in the struct acct in <file: 581 list is in the struct acct in <file:include/linux/acct.h>). It is
594 up to the user level program to do u 582 up to the user level program to do useful things with this
595 information. This is generally a go 583 information. This is generally a good idea, so say Y.
596 584
597 config BSD_PROCESS_ACCT_V3 585 config BSD_PROCESS_ACCT_V3
598 bool "BSD Process Accounting version 3 586 bool "BSD Process Accounting version 3 file format"
599 depends on BSD_PROCESS_ACCT 587 depends on BSD_PROCESS_ACCT
600 default n 588 default n
601 help 589 help
602 If you say Y here, the process accou 590 If you say Y here, the process accounting information is written
603 in a new file format that also logs 591 in a new file format that also logs the process IDs of each
604 process and its parent. Note that th 592 process and its parent. Note that this file format is incompatible
605 with previous v0/v1/v2 file formats, 593 with previous v0/v1/v2 file formats, so you will need updated tools
606 for processing it. A preliminary ver 594 for processing it. A preliminary version of these tools is available
607 at <http://www.gnu.org/software/acct 595 at <http://www.gnu.org/software/acct/>.
608 596
609 config TASKSTATS 597 config TASKSTATS
610 bool "Export task/process statistics t 598 bool "Export task/process statistics through netlink"
611 depends on NET 599 depends on NET
612 depends on MULTIUSER 600 depends on MULTIUSER
613 default n 601 default n
614 help 602 help
615 Export selected statistics for tasks 603 Export selected statistics for tasks/processes through the
616 generic netlink interface. Unlike BS 604 generic netlink interface. Unlike BSD process accounting, the
617 statistics are available during the 605 statistics are available during the lifetime of tasks/processes as
618 responses to commands. Like BSD acco 606 responses to commands. Like BSD accounting, they are sent to user
619 space on task exit. 607 space on task exit.
620 608
621 Say N if unsure. 609 Say N if unsure.
622 610
623 config TASK_DELAY_ACCT 611 config TASK_DELAY_ACCT
624 bool "Enable per-task delay accounting 612 bool "Enable per-task delay accounting"
625 depends on TASKSTATS 613 depends on TASKSTATS
626 select SCHED_INFO 614 select SCHED_INFO
627 help 615 help
628 Collect information on time spent by 616 Collect information on time spent by a task waiting for system
629 resources like cpu, synchronous bloc 617 resources like cpu, synchronous block I/O completion and swapping
630 in pages. Such statistics can help i 618 in pages. Such statistics can help in setting a task's priorities
631 relative to other tasks for cpu, io, 619 relative to other tasks for cpu, io, rss limits etc.
632 620
633 Say N if unsure. 621 Say N if unsure.
634 622
635 config TASK_XACCT 623 config TASK_XACCT
636 bool "Enable extended accounting over 624 bool "Enable extended accounting over taskstats"
637 depends on TASKSTATS 625 depends on TASKSTATS
638 help 626 help
639 Collect extended task accounting dat 627 Collect extended task accounting data and send the data
640 to userland for processing over the 628 to userland for processing over the taskstats interface.
641 629
642 Say N if unsure. 630 Say N if unsure.
643 631
644 config TASK_IO_ACCOUNTING 632 config TASK_IO_ACCOUNTING
645 bool "Enable per-task storage I/O acco 633 bool "Enable per-task storage I/O accounting"
646 depends on TASK_XACCT 634 depends on TASK_XACCT
647 help 635 help
648 Collect information on the number of 636 Collect information on the number of bytes of storage I/O which this
649 task has caused. 637 task has caused.
650 638
651 Say N if unsure. 639 Say N if unsure.
652 640
653 config PSI 641 config PSI
654 bool "Pressure stall information track 642 bool "Pressure stall information tracking"
655 select KERNFS 643 select KERNFS
656 help 644 help
657 Collect metrics that indicate how ov 645 Collect metrics that indicate how overcommitted the CPU, memory,
658 and IO capacity are in the system. 646 and IO capacity are in the system.
659 647
660 If you say Y here, the kernel will c 648 If you say Y here, the kernel will create /proc/pressure/ with the
661 pressure statistics files cpu, memor 649 pressure statistics files cpu, memory, and io. These will indicate
662 the share of walltime in which some 650 the share of walltime in which some or all tasks in the system are
663 delayed due to contention of the res 651 delayed due to contention of the respective resource.
664 652
665 In kernels with cgroup support, cgro 653 In kernels with cgroup support, cgroups (cgroup2 only) will
666 have cpu.pressure, memory.pressure, 654 have cpu.pressure, memory.pressure, and io.pressure files,
667 which aggregate pressure stalls for 655 which aggregate pressure stalls for the grouped tasks only.
668 656
669 For more details see Documentation/a 657 For more details see Documentation/accounting/psi.rst.
670 658
671 Say N if unsure. 659 Say N if unsure.
672 660
673 config PSI_DEFAULT_DISABLED 661 config PSI_DEFAULT_DISABLED
674 bool "Require boot parameter to enable 662 bool "Require boot parameter to enable pressure stall information tracking"
675 default n 663 default n
676 depends on PSI 664 depends on PSI
677 help 665 help
678 If set, pressure stall information t 666 If set, pressure stall information tracking will be disabled
679 per default but can be enabled throu 667 per default but can be enabled through passing psi=1 on the
680 kernel commandline during boot. 668 kernel commandline during boot.
681 669
682 This feature adds some code to the t 670 This feature adds some code to the task wakeup and sleep
683 paths of the scheduler. The overhead 671 paths of the scheduler. The overhead is too low to affect
684 common scheduling-intense workloads 672 common scheduling-intense workloads in practice (such as
685 webservers, memcache), but it does s 673 webservers, memcache), but it does show up in artificial
686 scheduler stress tests, such as hack 674 scheduler stress tests, such as hackbench.
687 675
688 If you are paranoid and not sure wha 676 If you are paranoid and not sure what the kernel will be
689 used for, say Y. 677 used for, say Y.
690 678
691 Say N if unsure. 679 Say N if unsure.
692 680
693 endmenu # "CPU/Task time and stats accounting" 681 endmenu # "CPU/Task time and stats accounting"
694 682
695 config CPU_ISOLATION 683 config CPU_ISOLATION
696 bool "CPU isolation" 684 bool "CPU isolation"
697 depends on SMP || COMPILE_TEST 685 depends on SMP || COMPILE_TEST
698 default y 686 default y
699 help 687 help
700 Make sure that CPUs running critical 688 Make sure that CPUs running critical tasks are not disturbed by
701 any source of "noise" such as unboun 689 any source of "noise" such as unbound workqueues, timers, kthreads...
702 Unbound jobs get offloaded to housek 690 Unbound jobs get offloaded to housekeeping CPUs. This is driven by
703 the "isolcpus=" boot parameter. 691 the "isolcpus=" boot parameter.
704 692
705 Say Y if unsure. 693 Say Y if unsure.
706 694
707 source "kernel/rcu/Kconfig" 695 source "kernel/rcu/Kconfig"
708 696
709 config IKCONFIG 697 config IKCONFIG
710 tristate "Kernel .config support" 698 tristate "Kernel .config support"
711 help 699 help
712 This option enables the complete Lin 700 This option enables the complete Linux kernel ".config" file
713 contents to be saved in the kernel. 701 contents to be saved in the kernel. It provides documentation
714 of which kernel options are used in 702 of which kernel options are used in a running kernel or in an
715 on-disk kernel. This information ca 703 on-disk kernel. This information can be extracted from the kernel
716 image file with the script scripts/e 704 image file with the script scripts/extract-ikconfig and used as
717 input to rebuild the current kernel 705 input to rebuild the current kernel or to build another kernel.
718 It can also be extracted from a runn 706 It can also be extracted from a running kernel by reading
719 /proc/config.gz if enabled (below). 707 /proc/config.gz if enabled (below).
720 708
721 config IKCONFIG_PROC 709 config IKCONFIG_PROC
722 bool "Enable access to .config through 710 bool "Enable access to .config through /proc/config.gz"
723 depends on IKCONFIG && PROC_FS 711 depends on IKCONFIG && PROC_FS
724 help 712 help
725 This option enables access to the ke 713 This option enables access to the kernel configuration file
726 through /proc/config.gz. 714 through /proc/config.gz.
727 715
728 config IKHEADERS 716 config IKHEADERS
729 tristate "Enable kernel headers throug 717 tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz"
730 depends on SYSFS 718 depends on SYSFS
731 help 719 help
732 This option enables access to the in 720 This option enables access to the in-kernel headers that are generated during
733 the build process. These can be used 721 the build process. These can be used to build eBPF tracing programs,
734 or similar programs. If you build t 722 or similar programs. If you build the headers as a module, a module called
735 kheaders.ko is built which can be lo 723 kheaders.ko is built which can be loaded on-demand to get access to headers.
736 724
737 config LOG_BUF_SHIFT 725 config LOG_BUF_SHIFT
738 int "Kernel log buffer size (16 => 64K 726 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
739 range 12 25 727 range 12 25
740 default 17 728 default 17
741 depends on PRINTK 729 depends on PRINTK
742 help 730 help
743 Select the minimal kernel log buffer 731 Select the minimal kernel log buffer size as a power of 2.
744 The final size is affected by LOG_CP 732 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
745 parameter, see below. Any higher siz 733 parameter, see below. Any higher size also might be forced
746 by "log_buf_len" boot parameter. 734 by "log_buf_len" boot parameter.
747 735
748 Examples: 736 Examples:
749 17 => 128 KB 737 17 => 128 KB
750 16 => 64 KB 738 16 => 64 KB
751 15 => 32 KB 739 15 => 32 KB
752 14 => 16 KB 740 14 => 16 KB
753 13 => 8 KB 741 13 => 8 KB
754 12 => 4 KB 742 12 => 4 KB
755 743
756 config LOG_CPU_MAX_BUF_SHIFT 744 config LOG_CPU_MAX_BUF_SHIFT
757 int "CPU kernel log buffer size contri 745 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
758 depends on SMP 746 depends on SMP
759 range 0 21 747 range 0 21
760 default 0 if BASE_SMALL 748 default 0 if BASE_SMALL
761 default 12 749 default 12
762 depends on PRINTK 750 depends on PRINTK
763 help 751 help
764 This option allows to increase the d 752 This option allows to increase the default ring buffer size
765 according to the number of CPUs. The 753 according to the number of CPUs. The value defines the contribution
766 of each CPU as a power of 2. The use 754 of each CPU as a power of 2. The used space is typically only few
767 lines however it might be much more 755 lines however it might be much more when problems are reported,
768 e.g. backtraces. 756 e.g. backtraces.
769 757
770 The increased size means that a new 758 The increased size means that a new buffer has to be allocated and
771 the original static one is unused. I 759 the original static one is unused. It makes sense only on systems
772 with more CPUs. Therefore this value 760 with more CPUs. Therefore this value is used only when the sum of
773 contributions is greater than the ha 761 contributions is greater than the half of the default kernel ring
774 buffer as defined by LOG_BUF_SHIFT. 762 buffer as defined by LOG_BUF_SHIFT. The default values are set
775 so that more than 16 CPUs are needed 763 so that more than 16 CPUs are needed to trigger the allocation.
776 764
777 Also this option is ignored when "lo 765 Also this option is ignored when "log_buf_len" kernel parameter is
778 used as it forces an exact (power of 766 used as it forces an exact (power of two) size of the ring buffer.
779 767
780 The number of possible CPUs is used 768 The number of possible CPUs is used for this computation ignoring
781 hotplugging making the computation o 769 hotplugging making the computation optimal for the worst case
782 scenario while allowing a simple alg 770 scenario while allowing a simple algorithm to be used from bootup.
783 771
784 Examples shift values and their mean 772 Examples shift values and their meaning:
785 17 => 128 KB for each CPU 773 17 => 128 KB for each CPU
786 16 => 64 KB for each CPU 774 16 => 64 KB for each CPU
787 15 => 32 KB for each CPU 775 15 => 32 KB for each CPU
788 14 => 16 KB for each CPU 776 14 => 16 KB for each CPU
789 13 => 8 KB for each CPU 777 13 => 8 KB for each CPU
790 12 => 4 KB for each CPU 778 12 => 4 KB for each CPU
791 779
792 config PRINTK_INDEX 780 config PRINTK_INDEX
793 bool "Printk indexing debugfs interfac 781 bool "Printk indexing debugfs interface"
794 depends on PRINTK && DEBUG_FS 782 depends on PRINTK && DEBUG_FS
795 help 783 help
796 Add support for indexing of all prin 784 Add support for indexing of all printk formats known at compile time
797 at <debugfs>/printk/index/<module>. 785 at <debugfs>/printk/index/<module>.
798 786
799 This can be used as part of maintain 787 This can be used as part of maintaining daemons which monitor
800 /dev/kmsg, as it permits auditing th 788 /dev/kmsg, as it permits auditing the printk formats present in a
801 kernel, allowing detection of cases 789 kernel, allowing detection of cases where monitored printks are
802 changed or no longer present. 790 changed or no longer present.
803 791
804 There is no additional runtime cost 792 There is no additional runtime cost to printk with this enabled.
805 793
806 # 794 #
807 # Architectures with an unreliable sched_clock 795 # Architectures with an unreliable sched_clock() should select this:
808 # 796 #
809 config HAVE_UNSTABLE_SCHED_CLOCK 797 config HAVE_UNSTABLE_SCHED_CLOCK
810 bool 798 bool
811 799
812 config GENERIC_SCHED_CLOCK 800 config GENERIC_SCHED_CLOCK
813 bool 801 bool
814 802
815 menu "Scheduler features" 803 menu "Scheduler features"
816 804
817 config UCLAMP_TASK 805 config UCLAMP_TASK
818 bool "Enable utilization clamping for 806 bool "Enable utilization clamping for RT/FAIR tasks"
819 depends on CPU_FREQ_GOV_SCHEDUTIL 807 depends on CPU_FREQ_GOV_SCHEDUTIL
820 help 808 help
821 This feature enables the scheduler t 809 This feature enables the scheduler to track the clamped utilization
822 of each CPU based on RUNNABLE tasks 810 of each CPU based on RUNNABLE tasks scheduled on that CPU.
823 811
824 With this option, the user can speci 812 With this option, the user can specify the min and max CPU
825 utilization allowed for RUNNABLE tas 813 utilization allowed for RUNNABLE tasks. The max utilization defines
826 the maximum frequency a task should 814 the maximum frequency a task should use while the min utilization
827 defines the minimum frequency it sho 815 defines the minimum frequency it should use.
828 816
829 Both min and max utilization clamp v 817 Both min and max utilization clamp values are hints to the scheduler,
830 aiming at improving its frequency se 818 aiming at improving its frequency selection policy, but they do not
831 enforce or grant any specific bandwi 819 enforce or grant any specific bandwidth for tasks.
832 820
833 If in doubt, say N. 821 If in doubt, say N.
834 822
835 config UCLAMP_BUCKETS_COUNT 823 config UCLAMP_BUCKETS_COUNT
836 int "Number of supported utilization c 824 int "Number of supported utilization clamp buckets"
837 range 5 20 825 range 5 20
838 default 5 826 default 5
839 depends on UCLAMP_TASK 827 depends on UCLAMP_TASK
840 help 828 help
841 Defines the number of clamp buckets 829 Defines the number of clamp buckets to use. The range of each bucket
842 will be SCHED_CAPACITY_SCALE/UCLAMP_ 830 will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the
843 number of clamp buckets the finer th 831 number of clamp buckets the finer their granularity and the higher
844 the precision of clamping aggregatio 832 the precision of clamping aggregation and tracking at run-time.
845 833
846 For example, with the minimum config 834 For example, with the minimum configuration value we will have 5
847 clamp buckets tracking 20% utilizati 835 clamp buckets tracking 20% utilization each. A 25% boosted tasks will
848 be refcounted in the [20..39]% bucke 836 be refcounted in the [20..39]% bucket and will set the bucket clamp
849 effective value to 25%. 837 effective value to 25%.
850 If a second 30% boosted task should 838 If a second 30% boosted task should be co-scheduled on the same CPU,
851 that task will be refcounted in the 839 that task will be refcounted in the same bucket of the first task and
852 it will boost the bucket clamp effec 840 it will boost the bucket clamp effective value to 30%.
853 The clamp effective value of a bucke 841 The clamp effective value of a bucket is reset to its nominal value
854 (20% in the example above) when ther 842 (20% in the example above) when there are no more tasks refcounted in
855 that bucket. 843 that bucket.
856 844
857 An additional boost/capping margin c 845 An additional boost/capping margin can be added to some tasks. In the
858 example above the 25% task will be b 846 example above the 25% task will be boosted to 30% until it exits the
859 CPU. If that should be considered no 847 CPU. If that should be considered not acceptable on certain systems,
860 it's always possible to reduce the m 848 it's always possible to reduce the margin by increasing the number of
861 clamp buckets to trade off used memo 849 clamp buckets to trade off used memory for run-time tracking
862 precision. 850 precision.
863 851
864 If in doubt, use the default value. 852 If in doubt, use the default value.
865 853
866 endmenu 854 endmenu
867 855
868 # 856 #
869 # For architectures that want to enable the su 857 # For architectures that want to enable the support for NUMA-affine scheduler
870 # balancing logic: 858 # balancing logic:
871 # 859 #
872 config ARCH_SUPPORTS_NUMA_BALANCING 860 config ARCH_SUPPORTS_NUMA_BALANCING
873 bool 861 bool
874 862
875 # 863 #
876 # For architectures that prefer to flush all T 864 # For architectures that prefer to flush all TLBs after a number of pages
877 # are unmapped instead of sending one IPI per 865 # are unmapped instead of sending one IPI per page to flush. The architecture
878 # must provide guarantees on what happens if a 866 # must provide guarantees on what happens if a clean TLB cache entry is
879 # written after the unmap. Details are in mm/r 867 # written after the unmap. Details are in mm/rmap.c near the check for
880 # should_defer_flush. The architecture should 868 # should_defer_flush. The architecture should also consider if the full flush
881 # and the refill costs are offset by the savin 869 # and the refill costs are offset by the savings of sending fewer IPIs.
882 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 870 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
883 bool 871 bool
884 872
885 config CC_HAS_INT128 873 config CC_HAS_INT128
886 def_bool !$(cc-option,$(m64-flag) -D__ 874 def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT
887 875
888 config CC_IMPLICIT_FALLTHROUGH 876 config CC_IMPLICIT_FALLTHROUGH
889 string 877 string
890 default "-Wimplicit-fallthrough=5" if 878 default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5)
891 default "-Wimplicit-fallthrough" if CC 879 default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough)
892 880
893 # Currently, disable gcc-10+ array-bounds glob 881 # Currently, disable gcc-10+ array-bounds globally.
894 # It's still broken in gcc-13, so no upper bou 882 # It's still broken in gcc-13, so no upper bound yet.
895 config GCC10_NO_ARRAY_BOUNDS 883 config GCC10_NO_ARRAY_BOUNDS
896 def_bool y 884 def_bool y
897 885
898 config CC_NO_ARRAY_BOUNDS 886 config CC_NO_ARRAY_BOUNDS
899 bool 887 bool
900 default y if CC_IS_GCC && GCC_VERSION 888 default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC10_NO_ARRAY_BOUNDS
901 889
902 # Currently, disable -Wstringop-overflow for G 890 # Currently, disable -Wstringop-overflow for GCC globally.
903 config GCC_NO_STRINGOP_OVERFLOW 891 config GCC_NO_STRINGOP_OVERFLOW
904 def_bool y 892 def_bool y
905 893
906 config CC_NO_STRINGOP_OVERFLOW 894 config CC_NO_STRINGOP_OVERFLOW
907 bool 895 bool
908 default y if CC_IS_GCC && GCC_NO_STRIN 896 default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW
909 897
910 config CC_STRINGOP_OVERFLOW 898 config CC_STRINGOP_OVERFLOW
911 bool 899 bool
912 default y if CC_IS_GCC && !CC_NO_STRIN 900 default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW
913 901
914 # 902 #
915 # For architectures that know their GCC __int1 903 # For architectures that know their GCC __int128 support is sound
916 # 904 #
917 config ARCH_SUPPORTS_INT128 905 config ARCH_SUPPORTS_INT128
918 bool 906 bool
919 907
920 # For architectures that (ab)use NUMA to repre 908 # For architectures that (ab)use NUMA to represent different memory regions
921 # all cpu-local but of different latencies, su 909 # all cpu-local but of different latencies, such as SuperH.
922 # 910 #
923 config ARCH_WANT_NUMA_VARIABLE_LOCALITY 911 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
924 bool 912 bool
925 913
926 config NUMA_BALANCING 914 config NUMA_BALANCING
927 bool "Memory placement aware NUMA sche 915 bool "Memory placement aware NUMA scheduler"
928 depends on ARCH_SUPPORTS_NUMA_BALANCIN 916 depends on ARCH_SUPPORTS_NUMA_BALANCING
929 depends on !ARCH_WANT_NUMA_VARIABLE_LO 917 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
930 depends on SMP && NUMA && MIGRATION && 918 depends on SMP && NUMA && MIGRATION && !PREEMPT_RT
931 help 919 help
932 This option adds support for automat 920 This option adds support for automatic NUMA aware memory/task placement.
933 The mechanism is quite primitive and 921 The mechanism is quite primitive and is based on migrating memory when
934 it has references to the node the ta 922 it has references to the node the task is running on.
935 923
936 This system will be inactive on UMA 924 This system will be inactive on UMA systems.
937 925
938 config NUMA_BALANCING_DEFAULT_ENABLED 926 config NUMA_BALANCING_DEFAULT_ENABLED
939 bool "Automatically enable NUMA aware 927 bool "Automatically enable NUMA aware memory/task placement"
940 default y 928 default y
941 depends on NUMA_BALANCING 929 depends on NUMA_BALANCING
942 help 930 help
943 If set, automatic NUMA balancing wil 931 If set, automatic NUMA balancing will be enabled if running on a NUMA
944 machine. 932 machine.
945 933
946 config SLAB_OBJ_EXT 934 config SLAB_OBJ_EXT
947 bool 935 bool
948 936
949 menuconfig CGROUPS 937 menuconfig CGROUPS
950 bool "Control Group support" 938 bool "Control Group support"
951 select KERNFS 939 select KERNFS
952 help 940 help
953 This option adds support for groupin 941 This option adds support for grouping sets of processes together, for
954 use with process control subsystems 942 use with process control subsystems such as Cpusets, CFS, memory
955 controls or device isolation. 943 controls or device isolation.
956 See 944 See
957 - Documentation/scheduler/sche 945 - Documentation/scheduler/sched-design-CFS.rst (CFS)
958 - Documentation/admin-guide/cg 946 - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation
959 and 947 and resource control)
960 948
961 Say N if unsure. 949 Say N if unsure.
962 950
963 if CGROUPS 951 if CGROUPS
964 952
965 config PAGE_COUNTER 953 config PAGE_COUNTER
966 bool 954 bool
967 955
968 config CGROUP_FAVOR_DYNMODS 956 config CGROUP_FAVOR_DYNMODS
969 bool "Favor dynamic modification laten 957 bool "Favor dynamic modification latency reduction by default"
970 help 958 help
971 This option enables the "favordynmod 959 This option enables the "favordynmods" mount option by default
972 which reduces the latencies of dynam 960 which reduces the latencies of dynamic cgroup modifications such
973 as task migrations and controller on 961 as task migrations and controller on/offs at the cost of making
974 hot path operations such as forks an 962 hot path operations such as forks and exits more expensive.
975 963
976 Say N if unsure. 964 Say N if unsure.
977 965
978 config MEMCG 966 config MEMCG
979 bool "Memory controller" 967 bool "Memory controller"
980 select PAGE_COUNTER 968 select PAGE_COUNTER
981 select EVENTFD 969 select EVENTFD
982 select SLAB_OBJ_EXT 970 select SLAB_OBJ_EXT
983 help 971 help
984 Provides control over the memory foo 972 Provides control over the memory footprint of tasks in a cgroup.
985 973
986 config MEMCG_V1 974 config MEMCG_V1
987 bool "Legacy cgroup v1 memory controll 975 bool "Legacy cgroup v1 memory controller"
988 depends on MEMCG 976 depends on MEMCG
989 default n 977 default n
990 help 978 help
991 Legacy cgroup v1 memory controller w 979 Legacy cgroup v1 memory controller which has been deprecated by
992 cgroup v2 implementation. The v1 is 980 cgroup v2 implementation. The v1 is there for legacy applications
993 which haven't migrated to the new cg 981 which haven't migrated to the new cgroup v2 interface yet. If you
994 do not have any such application the 982 do not have any such application then you are completely fine leaving
995 this option disabled. 983 this option disabled.
996 984
997 Please note that feature set of the 985 Please note that feature set of the legacy memory controller is likely
998 going to shrink due to deprecation p 986 going to shrink due to deprecation process. New deployments with v1
999 controller are highly discouraged. 987 controller are highly discouraged.
1000 988
1001 Say N if unsure. !! 989 San N is unsure.
1002 990
1003 config BLK_CGROUP 991 config BLK_CGROUP
1004 bool "IO controller" 992 bool "IO controller"
1005 depends on BLOCK 993 depends on BLOCK
1006 default n 994 default n
1007 help 995 help
1008 Generic block IO controller cgroup in 996 Generic block IO controller cgroup interface. This is the common
1009 cgroup interface which should be used 997 cgroup interface which should be used by various IO controlling
1010 policies. 998 policies.
1011 999
1012 Currently, CFQ IO scheduler uses it t 1000 Currently, CFQ IO scheduler uses it to recognize task groups and
1013 control disk bandwidth allocation (pr 1001 control disk bandwidth allocation (proportional time slice allocation)
1014 to such task groups. It is also used 1002 to such task groups. It is also used by bio throttling logic in
1015 block layer to implement upper limit 1003 block layer to implement upper limit in IO rates on a device.
1016 1004
1017 This option only enables generic Bloc 1005 This option only enables generic Block IO controller infrastructure.
1018 One needs to also enable actual IO co 1006 One needs to also enable actual IO controlling logic/policy. For
1019 enabling proportional weight division 1007 enabling proportional weight division of disk bandwidth in CFQ, set
1020 CONFIG_BFQ_GROUP_IOSCHED=y; for enabl 1008 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1021 CONFIG_BLK_DEV_THROTTLING=y. 1009 CONFIG_BLK_DEV_THROTTLING=y.
1022 1010
1023 See Documentation/admin-guide/cgroup- 1011 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information.
1024 1012
1025 config CGROUP_WRITEBACK 1013 config CGROUP_WRITEBACK
1026 bool 1014 bool
1027 depends on MEMCG && BLK_CGROUP 1015 depends on MEMCG && BLK_CGROUP
1028 default y 1016 default y
1029 1017
1030 menuconfig CGROUP_SCHED 1018 menuconfig CGROUP_SCHED
1031 bool "CPU controller" 1019 bool "CPU controller"
1032 default n 1020 default n
1033 help 1021 help
1034 This feature lets CPU scheduler rec 1022 This feature lets CPU scheduler recognize task groups and control CPU
1035 bandwidth allocation to such task g 1023 bandwidth allocation to such task groups. It uses cgroups to group
1036 tasks. 1024 tasks.
1037 1025
1038 if CGROUP_SCHED 1026 if CGROUP_SCHED
1039 config GROUP_SCHED_WEIGHT <<
1040 def_bool n <<
1041 <<
1042 config FAIR_GROUP_SCHED 1027 config FAIR_GROUP_SCHED
1043 bool "Group scheduling for SCHED_OTHE 1028 bool "Group scheduling for SCHED_OTHER"
1044 depends on CGROUP_SCHED 1029 depends on CGROUP_SCHED
1045 select GROUP_SCHED_WEIGHT <<
1046 default CGROUP_SCHED 1030 default CGROUP_SCHED
1047 1031
1048 config CFS_BANDWIDTH 1032 config CFS_BANDWIDTH
1049 bool "CPU bandwidth provisioning for 1033 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1050 depends on FAIR_GROUP_SCHED 1034 depends on FAIR_GROUP_SCHED
1051 default n 1035 default n
1052 help 1036 help
1053 This option allows users to define 1037 This option allows users to define CPU bandwidth rates (limits) for
1054 tasks running within the fair group 1038 tasks running within the fair group scheduler. Groups with no limit
1055 set are considered to be unconstrai 1039 set are considered to be unconstrained and will run with no
1056 restriction. 1040 restriction.
1057 See Documentation/scheduler/sched-b 1041 See Documentation/scheduler/sched-bwc.rst for more information.
1058 1042
1059 config RT_GROUP_SCHED 1043 config RT_GROUP_SCHED
1060 bool "Group scheduling for SCHED_RR/F 1044 bool "Group scheduling for SCHED_RR/FIFO"
1061 depends on CGROUP_SCHED 1045 depends on CGROUP_SCHED
1062 default n 1046 default n
1063 help 1047 help
1064 This feature lets you explicitly al 1048 This feature lets you explicitly allocate real CPU bandwidth
1065 to task groups. If enabled, it will 1049 to task groups. If enabled, it will also make it impossible to
1066 schedule realtime tasks for non-roo 1050 schedule realtime tasks for non-root users until you allocate
1067 realtime bandwidth for them. 1051 realtime bandwidth for them.
1068 See Documentation/scheduler/sched-r 1052 See Documentation/scheduler/sched-rt-group.rst for more information.
1069 1053
1070 config EXT_GROUP_SCHED <<
1071 bool <<
1072 depends on SCHED_CLASS_EXT && CGROUP_ <<
1073 select GROUP_SCHED_WEIGHT <<
1074 default y <<
1075 <<
1076 endif #CGROUP_SCHED 1054 endif #CGROUP_SCHED
1077 1055
1078 config SCHED_MM_CID 1056 config SCHED_MM_CID
1079 def_bool y 1057 def_bool y
1080 depends on SMP && RSEQ 1058 depends on SMP && RSEQ
1081 1059
1082 config UCLAMP_TASK_GROUP 1060 config UCLAMP_TASK_GROUP
1083 bool "Utilization clamping per group 1061 bool "Utilization clamping per group of tasks"
1084 depends on CGROUP_SCHED 1062 depends on CGROUP_SCHED
1085 depends on UCLAMP_TASK 1063 depends on UCLAMP_TASK
1086 default n 1064 default n
1087 help 1065 help
1088 This feature enables the scheduler 1066 This feature enables the scheduler to track the clamped utilization
1089 of each CPU based on RUNNABLE tasks 1067 of each CPU based on RUNNABLE tasks currently scheduled on that CPU.
1090 1068
1091 When this option is enabled, the us 1069 When this option is enabled, the user can specify a min and max
1092 CPU bandwidth which is allowed for 1070 CPU bandwidth which is allowed for each single task in a group.
1093 The max bandwidth allows to clamp t 1071 The max bandwidth allows to clamp the maximum frequency a task
1094 can use, while the min bandwidth al 1072 can use, while the min bandwidth allows to define a minimum
1095 frequency a task will always use. 1073 frequency a task will always use.
1096 1074
1097 When task group based utilization c 1075 When task group based utilization clamping is enabled, an eventually
1098 specified task-specific clamp value 1076 specified task-specific clamp value is constrained by the cgroup
1099 specified clamp value. Both minimum 1077 specified clamp value. Both minimum and maximum task clamping cannot
1100 be bigger than the corresponding cl 1078 be bigger than the corresponding clamping defined at task group level.
1101 1079
1102 If in doubt, say N. 1080 If in doubt, say N.
1103 1081
1104 config CGROUP_PIDS 1082 config CGROUP_PIDS
1105 bool "PIDs controller" 1083 bool "PIDs controller"
1106 help 1084 help
1107 Provides enforcement of process num 1085 Provides enforcement of process number limits in the scope of a
1108 cgroup. Any attempt to fork more pr 1086 cgroup. Any attempt to fork more processes than is allowed in the
1109 cgroup will fail. PIDs are fundamen 1087 cgroup will fail. PIDs are fundamentally a global resource because it
1110 is fairly trivial to reach PID exha 1088 is fairly trivial to reach PID exhaustion before you reach even a
1111 conservative kmemcg limit. As a res 1089 conservative kmemcg limit. As a result, it is possible to grind a
1112 system to halt without being limite 1090 system to halt without being limited by other cgroup policies. The
1113 PIDs controller is designed to stop 1091 PIDs controller is designed to stop this from happening.
1114 1092
1115 It should be noted that organisatio 1093 It should be noted that organisational operations (such as attaching
1116 to a cgroup hierarchy) will *not* b 1094 to a cgroup hierarchy) will *not* be blocked by the PIDs controller,
1117 since the PIDs limit only affects a 1095 since the PIDs limit only affects a process's ability to fork, not to
1118 attach to a cgroup. 1096 attach to a cgroup.
1119 1097
1120 config CGROUP_RDMA 1098 config CGROUP_RDMA
1121 bool "RDMA controller" 1099 bool "RDMA controller"
1122 help 1100 help
1123 Provides enforcement of RDMA resour 1101 Provides enforcement of RDMA resources defined by IB stack.
1124 It is fairly easy for consumers to 1102 It is fairly easy for consumers to exhaust RDMA resources, which
1125 can result into resource unavailabi 1103 can result into resource unavailability to other consumers.
1126 RDMA controller is designed to stop 1104 RDMA controller is designed to stop this from happening.
1127 Attaching processes with active RDM 1105 Attaching processes with active RDMA resources to the cgroup
1128 hierarchy is allowed even if can cr 1106 hierarchy is allowed even if can cross the hierarchy's limit.
1129 1107
1130 config CGROUP_FREEZER 1108 config CGROUP_FREEZER
1131 bool "Freezer controller" 1109 bool "Freezer controller"
1132 help 1110 help
1133 Provides a way to freeze and unfree 1111 Provides a way to freeze and unfreeze all tasks in a
1134 cgroup. 1112 cgroup.
1135 1113
1136 This option affects the ORIGINAL cg 1114 This option affects the ORIGINAL cgroup interface. The cgroup2 memory
1137 controller includes important in-ke 1115 controller includes important in-kernel memory consumers per default.
1138 1116
1139 If you're using cgroup2, say N. 1117 If you're using cgroup2, say N.
1140 1118
1141 config CGROUP_HUGETLB 1119 config CGROUP_HUGETLB
1142 bool "HugeTLB controller" 1120 bool "HugeTLB controller"
1143 depends on HUGETLB_PAGE 1121 depends on HUGETLB_PAGE
1144 select PAGE_COUNTER 1122 select PAGE_COUNTER
1145 default n 1123 default n
1146 help 1124 help
1147 Provides a cgroup controller for Hu 1125 Provides a cgroup controller for HugeTLB pages.
1148 When you enable this, you can put a 1126 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1149 The limit is enforced during page f 1127 The limit is enforced during page fault. Since HugeTLB doesn't
1150 support page reclaim, enforcing the 1128 support page reclaim, enforcing the limit at page fault time implies
1151 that, the application will get SIGB 1129 that, the application will get SIGBUS signal if it tries to access
1152 HugeTLB pages beyond its limit. Thi 1130 HugeTLB pages beyond its limit. This requires the application to know
1153 beforehand how much HugeTLB pages i 1131 beforehand how much HugeTLB pages it would require for its use. The
1154 control group is tracked in the thi 1132 control group is tracked in the third page lru pointer. This means
1155 that we cannot use the controller w 1133 that we cannot use the controller with huge page less than 3 pages.
1156 1134
1157 config CPUSETS 1135 config CPUSETS
1158 bool "Cpuset controller" 1136 bool "Cpuset controller"
1159 depends on SMP 1137 depends on SMP
1160 help 1138 help
1161 This option will let you create and 1139 This option will let you create and manage CPUSETs which
1162 allow dynamically partitioning a sy 1140 allow dynamically partitioning a system into sets of CPUs and
1163 Memory Nodes and assigning tasks to 1141 Memory Nodes and assigning tasks to run only within those sets.
1164 This is primarily useful on large S 1142 This is primarily useful on large SMP or NUMA systems.
1165 1143
1166 Say N if unsure. 1144 Say N if unsure.
1167 1145
1168 config CPUSETS_V1 <<
1169 bool "Legacy cgroup v1 cpusets contro <<
1170 depends on CPUSETS <<
1171 default n <<
1172 help <<
1173 Legacy cgroup v1 cpusets controller <<
1174 cgroup v2 implementation. The v1 is <<
1175 which haven't migrated to the new c <<
1176 do not have any such application th <<
1177 this option disabled. <<
1178 <<
1179 Say N if unsure. <<
1180 <<
1181 config PROC_PID_CPUSET 1146 config PROC_PID_CPUSET
1182 bool "Include legacy /proc/<pid>/cpus 1147 bool "Include legacy /proc/<pid>/cpuset file"
1183 depends on CPUSETS 1148 depends on CPUSETS
1184 default y 1149 default y
1185 1150
1186 config CGROUP_DEVICE 1151 config CGROUP_DEVICE
1187 bool "Device controller" 1152 bool "Device controller"
1188 help 1153 help
1189 Provides a cgroup controller implem 1154 Provides a cgroup controller implementing whitelists for
1190 devices which a process in the cgro 1155 devices which a process in the cgroup can mknod or open.
1191 1156
1192 config CGROUP_CPUACCT 1157 config CGROUP_CPUACCT
1193 bool "Simple CPU accounting controlle 1158 bool "Simple CPU accounting controller"
1194 help 1159 help
1195 Provides a simple controller for mo 1160 Provides a simple controller for monitoring the
1196 total CPU consumed by the tasks in 1161 total CPU consumed by the tasks in a cgroup.
1197 1162
1198 config CGROUP_PERF 1163 config CGROUP_PERF
1199 bool "Perf controller" 1164 bool "Perf controller"
1200 depends on PERF_EVENTS 1165 depends on PERF_EVENTS
1201 help 1166 help
1202 This option extends the perf per-cp 1167 This option extends the perf per-cpu mode to restrict monitoring
1203 to threads which belong to the cgro 1168 to threads which belong to the cgroup specified and run on the
1204 designated cpu. Or this can be use 1169 designated cpu. Or this can be used to have cgroup ID in samples
1205 so that it can monitor performance 1170 so that it can monitor performance events among cgroups.
1206 1171
1207 Say N if unsure. 1172 Say N if unsure.
1208 1173
1209 config CGROUP_BPF 1174 config CGROUP_BPF
1210 bool "Support for eBPF programs attac 1175 bool "Support for eBPF programs attached to cgroups"
1211 depends on BPF_SYSCALL 1176 depends on BPF_SYSCALL
1212 select SOCK_CGROUP_DATA 1177 select SOCK_CGROUP_DATA
1213 help 1178 help
1214 Allow attaching eBPF programs to a 1179 Allow attaching eBPF programs to a cgroup using the bpf(2)
1215 syscall command BPF_PROG_ATTACH. 1180 syscall command BPF_PROG_ATTACH.
1216 1181
1217 In which context these programs are 1182 In which context these programs are accessed depends on the type
1218 of attachment. For instance, progra 1183 of attachment. For instance, programs that are attached using
1219 BPF_CGROUP_INET_INGRESS will be exe 1184 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
1220 inet sockets. 1185 inet sockets.
1221 1186
1222 config CGROUP_MISC 1187 config CGROUP_MISC
1223 bool "Misc resource controller" 1188 bool "Misc resource controller"
1224 default n 1189 default n
1225 help 1190 help
1226 Provides a controller for miscellan 1191 Provides a controller for miscellaneous resources on a host.
1227 1192
1228 Miscellaneous scalar resources are 1193 Miscellaneous scalar resources are the resources on the host system
1229 which cannot be abstracted like the 1194 which cannot be abstracted like the other cgroups. This controller
1230 tracks and limits the miscellaneous 1195 tracks and limits the miscellaneous resources used by a process
1231 attached to a cgroup hierarchy. 1196 attached to a cgroup hierarchy.
1232 1197
1233 For more information, please check 1198 For more information, please check misc cgroup section in
1234 /Documentation/admin-guide/cgroup-v 1199 /Documentation/admin-guide/cgroup-v2.rst.
1235 1200
1236 config CGROUP_DEBUG 1201 config CGROUP_DEBUG
1237 bool "Debug controller" 1202 bool "Debug controller"
1238 default n 1203 default n
1239 depends on DEBUG_KERNEL 1204 depends on DEBUG_KERNEL
1240 help 1205 help
1241 This option enables a simple contro 1206 This option enables a simple controller that exports
1242 debugging information about the cgr 1207 debugging information about the cgroups framework. This
1243 controller is for control cgroup de 1208 controller is for control cgroup debugging only. Its
1244 interfaces are not stable. 1209 interfaces are not stable.
1245 1210
1246 Say N. 1211 Say N.
1247 1212
1248 config SOCK_CGROUP_DATA 1213 config SOCK_CGROUP_DATA
1249 bool 1214 bool
1250 default n 1215 default n
1251 1216
1252 endif # CGROUPS 1217 endif # CGROUPS
1253 1218
1254 menuconfig NAMESPACES 1219 menuconfig NAMESPACES
1255 bool "Namespaces support" if EXPERT 1220 bool "Namespaces support" if EXPERT
1256 depends on MULTIUSER 1221 depends on MULTIUSER
1257 default !EXPERT 1222 default !EXPERT
1258 help 1223 help
1259 Provides the way to make tasks work 1224 Provides the way to make tasks work with different objects using
1260 the same id. For example same IPC i 1225 the same id. For example same IPC id may refer to different objects
1261 or same user id or pid may refer to 1226 or same user id or pid may refer to different tasks when used in
1262 different namespaces. 1227 different namespaces.
1263 1228
1264 if NAMESPACES 1229 if NAMESPACES
1265 1230
1266 config UTS_NS 1231 config UTS_NS
1267 bool "UTS namespace" 1232 bool "UTS namespace"
1268 default y 1233 default y
1269 help 1234 help
1270 In this namespace tasks see differe 1235 In this namespace tasks see different info provided with the
1271 uname() system call 1236 uname() system call
1272 1237
1273 config TIME_NS 1238 config TIME_NS
1274 bool "TIME namespace" 1239 bool "TIME namespace"
1275 depends on GENERIC_VDSO_TIME_NS 1240 depends on GENERIC_VDSO_TIME_NS
1276 default y 1241 default y
1277 help 1242 help
1278 In this namespace boottime and mono 1243 In this namespace boottime and monotonic clocks can be set.
1279 The time will keep going with the s 1244 The time will keep going with the same pace.
1280 1245
1281 config IPC_NS 1246 config IPC_NS
1282 bool "IPC namespace" 1247 bool "IPC namespace"
1283 depends on (SYSVIPC || POSIX_MQUEUE) 1248 depends on (SYSVIPC || POSIX_MQUEUE)
1284 default y 1249 default y
1285 help 1250 help
1286 In this namespace tasks work with I 1251 In this namespace tasks work with IPC ids which correspond to
1287 different IPC objects in different 1252 different IPC objects in different namespaces.
1288 1253
1289 config USER_NS 1254 config USER_NS
1290 bool "User namespace" 1255 bool "User namespace"
1291 default n 1256 default n
1292 help 1257 help
1293 This allows containers, i.e. vserve 1258 This allows containers, i.e. vservers, to use user namespaces
1294 to provide different user info for 1259 to provide different user info for different servers.
1295 1260
1296 When user namespaces are enabled in 1261 When user namespaces are enabled in the kernel it is
1297 recommended that the MEMCG option a 1262 recommended that the MEMCG option also be enabled and that
1298 user-space use the memory control g 1263 user-space use the memory control groups to limit the amount
1299 of memory a memory unprivileged use 1264 of memory a memory unprivileged users can use.
1300 1265
1301 If unsure, say N. 1266 If unsure, say N.
1302 1267
1303 config PID_NS 1268 config PID_NS
1304 bool "PID Namespaces" 1269 bool "PID Namespaces"
1305 default y 1270 default y
1306 help 1271 help
1307 Support process id namespaces. Thi 1272 Support process id namespaces. This allows having multiple
1308 processes with the same pid as long 1273 processes with the same pid as long as they are in different
1309 pid namespaces. This is a building 1274 pid namespaces. This is a building block of containers.
1310 1275
1311 config NET_NS 1276 config NET_NS
1312 bool "Network namespace" 1277 bool "Network namespace"
1313 depends on NET 1278 depends on NET
1314 default y 1279 default y
1315 help 1280 help
1316 Allow user space to create what app 1281 Allow user space to create what appear to be multiple instances
1317 of the network stack. 1282 of the network stack.
1318 1283
1319 endif # NAMESPACES 1284 endif # NAMESPACES
1320 1285
1321 config CHECKPOINT_RESTORE 1286 config CHECKPOINT_RESTORE
1322 bool "Checkpoint/restore support" 1287 bool "Checkpoint/restore support"
1323 depends on PROC_FS 1288 depends on PROC_FS
1324 select PROC_CHILDREN 1289 select PROC_CHILDREN
1325 select KCMP 1290 select KCMP
1326 default n 1291 default n
1327 help 1292 help
1328 Enables additional kernel features 1293 Enables additional kernel features in a sake of checkpoint/restore.
1329 In particular it adds auxiliary prc 1294 In particular it adds auxiliary prctl codes to setup process text,
1330 data and heap segment sizes, and a 1295 data and heap segment sizes, and a few additional /proc filesystem
1331 entries. 1296 entries.
1332 1297
1333 If unsure, say N here. 1298 If unsure, say N here.
1334 1299
1335 config SCHED_AUTOGROUP 1300 config SCHED_AUTOGROUP
1336 bool "Automatic process group schedul 1301 bool "Automatic process group scheduling"
1337 select CGROUPS 1302 select CGROUPS
1338 select CGROUP_SCHED 1303 select CGROUP_SCHED
1339 select FAIR_GROUP_SCHED 1304 select FAIR_GROUP_SCHED
1340 help 1305 help
1341 This option optimizes the scheduler 1306 This option optimizes the scheduler for common desktop workloads by
1342 automatically creating and populati 1307 automatically creating and populating task groups. This separation
1343 of workloads isolates aggressive CP 1308 of workloads isolates aggressive CPU burners (like build jobs) from
1344 desktop applications. Task group a 1309 desktop applications. Task group autogeneration is currently based
1345 upon task session. 1310 upon task session.
1346 1311
1347 config RELAY 1312 config RELAY
1348 bool "Kernel->user space relay suppor 1313 bool "Kernel->user space relay support (formerly relayfs)"
1349 select IRQ_WORK 1314 select IRQ_WORK
1350 help 1315 help
1351 This option enables support for rel 1316 This option enables support for relay interface support in
1352 certain file systems (such as debug 1317 certain file systems (such as debugfs).
1353 It is designed to provide an effici 1318 It is designed to provide an efficient mechanism for tools and
1354 facilities to relay large amounts o 1319 facilities to relay large amounts of data from kernel space to
1355 user space. 1320 user space.
1356 1321
1357 If unsure, say N. 1322 If unsure, say N.
1358 1323
1359 config BLK_DEV_INITRD 1324 config BLK_DEV_INITRD
1360 bool "Initial RAM filesystem and RAM 1325 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1361 help 1326 help
1362 The initial RAM filesystem is a ram 1327 The initial RAM filesystem is a ramfs which is loaded by the
1363 boot loader (loadlin or lilo) and t 1328 boot loader (loadlin or lilo) and that is mounted as root
1364 before the normal boot procedure. I 1329 before the normal boot procedure. It is typically used to
1365 load modules needed to mount the "r 1330 load modules needed to mount the "real" root file system,
1366 etc. See <file:Documentation/admin- 1331 etc. See <file:Documentation/admin-guide/initrd.rst> for details.
1367 1332
1368 If RAM disk support (BLK_DEV_RAM) i 1333 If RAM disk support (BLK_DEV_RAM) is also included, this
1369 also enables initial RAM disk (init 1334 also enables initial RAM disk (initrd) support and adds
1370 15 Kbytes (more on some other archi 1335 15 Kbytes (more on some other architectures) to the kernel size.
1371 1336
1372 If unsure say Y. 1337 If unsure say Y.
1373 1338
1374 if BLK_DEV_INITRD 1339 if BLK_DEV_INITRD
1375 1340
1376 source "usr/Kconfig" 1341 source "usr/Kconfig"
1377 1342
1378 endif 1343 endif
1379 1344
1380 config BOOT_CONFIG 1345 config BOOT_CONFIG
1381 bool "Boot config support" 1346 bool "Boot config support"
1382 select BLK_DEV_INITRD if !BOOT_CONFIG 1347 select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED
1383 help 1348 help
1384 Extra boot config allows system adm 1349 Extra boot config allows system admin to pass a config file as
1385 complemental extension of kernel cm 1350 complemental extension of kernel cmdline when booting.
1386 The boot config file must be attach 1351 The boot config file must be attached at the end of initramfs
1387 with checksum, size and magic word. 1352 with checksum, size and magic word.
1388 See <file:Documentation/admin-guide 1353 See <file:Documentation/admin-guide/bootconfig.rst> for details.
1389 1354
1390 If unsure, say Y. 1355 If unsure, say Y.
1391 1356
1392 config BOOT_CONFIG_FORCE 1357 config BOOT_CONFIG_FORCE
1393 bool "Force unconditional bootconfig 1358 bool "Force unconditional bootconfig processing"
1394 depends on BOOT_CONFIG 1359 depends on BOOT_CONFIG
1395 default y if BOOT_CONFIG_EMBED 1360 default y if BOOT_CONFIG_EMBED
1396 help 1361 help
1397 With this Kconfig option set, BOOT_ 1362 With this Kconfig option set, BOOT_CONFIG processing is carried
1398 out even when the "bootconfig" kern 1363 out even when the "bootconfig" kernel-boot parameter is omitted.
1399 In fact, with this Kconfig option s 1364 In fact, with this Kconfig option set, there is no way to
1400 make the kernel ignore the BOOT_CON 1365 make the kernel ignore the BOOT_CONFIG-supplied kernel-boot
1401 parameters. 1366 parameters.
1402 1367
1403 If unsure, say N. 1368 If unsure, say N.
1404 1369
1405 config BOOT_CONFIG_EMBED 1370 config BOOT_CONFIG_EMBED
1406 bool "Embed bootconfig file in the ke 1371 bool "Embed bootconfig file in the kernel"
1407 depends on BOOT_CONFIG 1372 depends on BOOT_CONFIG
1408 help 1373 help
1409 Embed a bootconfig file given by BO 1374 Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the
1410 kernel. Usually, the bootconfig fil 1375 kernel. Usually, the bootconfig file is loaded with the initrd
1411 image. But if the system doesn't su 1376 image. But if the system doesn't support initrd, this option will
1412 help you by embedding a bootconfig 1377 help you by embedding a bootconfig file while building the kernel.
1413 1378
1414 If unsure, say N. 1379 If unsure, say N.
1415 1380
1416 config BOOT_CONFIG_EMBED_FILE 1381 config BOOT_CONFIG_EMBED_FILE
1417 string "Embedded bootconfig file path 1382 string "Embedded bootconfig file path"
1418 depends on BOOT_CONFIG_EMBED 1383 depends on BOOT_CONFIG_EMBED
1419 help 1384 help
1420 Specify a bootconfig file which wil 1385 Specify a bootconfig file which will be embedded to the kernel.
1421 This bootconfig will be used if the 1386 This bootconfig will be used if there is no initrd or no other
1422 bootconfig in the initrd. 1387 bootconfig in the initrd.
1423 1388
1424 config INITRAMFS_PRESERVE_MTIME 1389 config INITRAMFS_PRESERVE_MTIME
1425 bool "Preserve cpio archive mtimes in 1390 bool "Preserve cpio archive mtimes in initramfs"
1426 default y 1391 default y
1427 help 1392 help
1428 Each entry in an initramfs cpio arc 1393 Each entry in an initramfs cpio archive carries an mtime value. When
1429 enabled, extracted cpio items take 1394 enabled, extracted cpio items take this mtime, with directory mtime
1430 setting deferred until after creati 1395 setting deferred until after creation of any child entries.
1431 1396
1432 If unsure, say Y. 1397 If unsure, say Y.
1433 1398
1434 choice 1399 choice
1435 prompt "Compiler optimization level" 1400 prompt "Compiler optimization level"
1436 default CC_OPTIMIZE_FOR_PERFORMANCE 1401 default CC_OPTIMIZE_FOR_PERFORMANCE
1437 1402
1438 config CC_OPTIMIZE_FOR_PERFORMANCE 1403 config CC_OPTIMIZE_FOR_PERFORMANCE
1439 bool "Optimize for performance (-O2)" 1404 bool "Optimize for performance (-O2)"
1440 help 1405 help
1441 This is the default optimization le 1406 This is the default optimization level for the kernel, building
1442 with the "-O2" compiler flag for be 1407 with the "-O2" compiler flag for best performance and most
1443 helpful compile-time warnings. 1408 helpful compile-time warnings.
1444 1409
1445 config CC_OPTIMIZE_FOR_SIZE 1410 config CC_OPTIMIZE_FOR_SIZE
1446 bool "Optimize for size (-Os)" 1411 bool "Optimize for size (-Os)"
1447 help 1412 help
1448 Choosing this option will pass "-Os 1413 Choosing this option will pass "-Os" to your compiler resulting
1449 in a smaller kernel. 1414 in a smaller kernel.
1450 1415
1451 endchoice 1416 endchoice
1452 1417
1453 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1418 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1454 bool 1419 bool
1455 help 1420 help
1456 This requires that the arch annotat 1421 This requires that the arch annotates or otherwise protects
1457 its external entry points from bein 1422 its external entry points from being discarded. Linker scripts
1458 must also merge .text.*, .data.*, a 1423 must also merge .text.*, .data.*, and .bss.* correctly into
1459 output sections. Care must be taken 1424 output sections. Care must be taken not to pull in unrelated
1460 sections (e.g., '.text.init'). Typi 1425 sections (e.g., '.text.init'). Typically '.' in section names
1461 is used to distinguish them from la 1426 is used to distinguish them from label names / C identifiers.
1462 1427
1463 config LD_DEAD_CODE_DATA_ELIMINATION 1428 config LD_DEAD_CODE_DATA_ELIMINATION
1464 bool "Dead code and data elimination 1429 bool "Dead code and data elimination (EXPERIMENTAL)"
1465 depends on HAVE_LD_DEAD_CODE_DATA_ELI 1430 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1466 depends on EXPERT 1431 depends on EXPERT
1467 depends on $(cc-option,-ffunction-sec 1432 depends on $(cc-option,-ffunction-sections -fdata-sections)
1468 depends on $(ld-option,--gc-sections) 1433 depends on $(ld-option,--gc-sections)
1469 help 1434 help
1470 Enable this if you want to do dead 1435 Enable this if you want to do dead code and data elimination with
1471 the linker by compiling with -ffunc 1436 the linker by compiling with -ffunction-sections -fdata-sections,
1472 and linking with --gc-sections. 1437 and linking with --gc-sections.
1473 1438
1474 This can reduce on disk and in-memo 1439 This can reduce on disk and in-memory size of the kernel
1475 code and static data, particularly 1440 code and static data, particularly for small configs and
1476 on small systems. This has the poss 1441 on small systems. This has the possibility of introducing
1477 silently broken kernel if the requi 1442 silently broken kernel if the required annotations are not
1478 present. This option is not well te 1443 present. This option is not well tested yet, so use at your
1479 own risk. 1444 own risk.
1480 1445
1481 config LD_ORPHAN_WARN 1446 config LD_ORPHAN_WARN
1482 def_bool y 1447 def_bool y
1483 depends on ARCH_WANT_LD_ORPHAN_WARN 1448 depends on ARCH_WANT_LD_ORPHAN_WARN
1484 depends on $(ld-option,--orphan-handl 1449 depends on $(ld-option,--orphan-handling=warn)
1485 depends on $(ld-option,--orphan-handl 1450 depends on $(ld-option,--orphan-handling=error)
1486 1451
1487 config LD_ORPHAN_WARN_LEVEL 1452 config LD_ORPHAN_WARN_LEVEL
1488 string 1453 string
1489 depends on LD_ORPHAN_WARN 1454 depends on LD_ORPHAN_WARN
1490 default "error" if WERROR 1455 default "error" if WERROR
1491 default "warn" 1456 default "warn"
1492 1457
1493 config SYSCTL 1458 config SYSCTL
1494 bool 1459 bool
1495 1460
1496 config HAVE_UID16 1461 config HAVE_UID16
1497 bool 1462 bool
1498 1463
1499 config SYSCTL_EXCEPTION_TRACE 1464 config SYSCTL_EXCEPTION_TRACE
1500 bool 1465 bool
1501 help 1466 help
1502 Enable support for /proc/sys/debug/ 1467 Enable support for /proc/sys/debug/exception-trace.
1503 1468
1504 config SYSCTL_ARCH_UNALIGN_NO_WARN 1469 config SYSCTL_ARCH_UNALIGN_NO_WARN
1505 bool 1470 bool
1506 help 1471 help
1507 Enable support for /proc/sys/kernel 1472 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1508 Allows arch to define/use @no_unali 1473 Allows arch to define/use @no_unaligned_warning to possibly warn
1509 about unaligned access emulation go 1474 about unaligned access emulation going on under the hood.
1510 1475
1511 config SYSCTL_ARCH_UNALIGN_ALLOW 1476 config SYSCTL_ARCH_UNALIGN_ALLOW
1512 bool 1477 bool
1513 help 1478 help
1514 Enable support for /proc/sys/kernel 1479 Enable support for /proc/sys/kernel/unaligned-trap
1515 Allows arches to define/use @unalig 1480 Allows arches to define/use @unaligned_enabled to runtime toggle
1516 the unaligned access emulation. 1481 the unaligned access emulation.
1517 see arch/parisc/kernel/unaligned.c 1482 see arch/parisc/kernel/unaligned.c for reference
1518 1483
1519 config HAVE_PCSPKR_PLATFORM 1484 config HAVE_PCSPKR_PLATFORM
1520 bool 1485 bool
1521 1486
1522 menuconfig EXPERT 1487 menuconfig EXPERT
1523 bool "Configure standard kernel featu 1488 bool "Configure standard kernel features (expert users)"
1524 # Unhide debug options, to make the o 1489 # Unhide debug options, to make the on-by-default options visible
1525 select DEBUG_KERNEL 1490 select DEBUG_KERNEL
1526 help 1491 help
1527 This option allows certain base ker 1492 This option allows certain base kernel options and settings
1528 to be disabled or tweaked. This is 1493 to be disabled or tweaked. This is for specialized
1529 environments which can tolerate a " 1494 environments which can tolerate a "non-standard" kernel.
1530 Only use this if you really know wh 1495 Only use this if you really know what you are doing.
1531 1496
1532 config UID16 1497 config UID16
1533 bool "Enable 16-bit UID system calls" 1498 bool "Enable 16-bit UID system calls" if EXPERT
1534 depends on HAVE_UID16 && MULTIUSER 1499 depends on HAVE_UID16 && MULTIUSER
1535 default y 1500 default y
1536 help 1501 help
1537 This enables the legacy 16-bit UID 1502 This enables the legacy 16-bit UID syscall wrappers.
1538 1503
1539 config MULTIUSER 1504 config MULTIUSER
1540 bool "Multiple users, groups and capa 1505 bool "Multiple users, groups and capabilities support" if EXPERT
1541 default y 1506 default y
1542 help 1507 help
1543 This option enables support for non 1508 This option enables support for non-root users, groups and
1544 capabilities. 1509 capabilities.
1545 1510
1546 If you say N here, all processes wi 1511 If you say N here, all processes will run with UID 0, GID 0, and all
1547 possible capabilities. Saying N he 1512 possible capabilities. Saying N here also compiles out support for
1548 system calls related to UIDs, GIDs, 1513 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1549 setgid, and capset. 1514 setgid, and capset.
1550 1515
1551 If unsure, say Y here. 1516 If unsure, say Y here.
1552 1517
1553 config SGETMASK_SYSCALL 1518 config SGETMASK_SYSCALL
1554 bool "sgetmask/ssetmask syscalls supp 1519 bool "sgetmask/ssetmask syscalls support" if EXPERT
1555 default PARISC || M68K || PPC || MIPS 1520 default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH
1556 help 1521 help
1557 sys_sgetmask and sys_ssetmask are o 1522 sys_sgetmask and sys_ssetmask are obsolete system calls
1558 no longer supported in libc but sti 1523 no longer supported in libc but still enabled by default in some
1559 architectures. 1524 architectures.
1560 1525
1561 If unsure, leave the default option 1526 If unsure, leave the default option here.
1562 1527
1563 config SYSFS_SYSCALL 1528 config SYSFS_SYSCALL
1564 bool "Sysfs syscall support" if EXPER 1529 bool "Sysfs syscall support" if EXPERT
1565 default y 1530 default y
1566 help 1531 help
1567 sys_sysfs is an obsolete system cal 1532 sys_sysfs is an obsolete system call no longer supported in libc.
1568 Note that disabling this option is 1533 Note that disabling this option is more secure but might break
1569 compatibility with some systems. 1534 compatibility with some systems.
1570 1535
1571 If unsure say Y here. 1536 If unsure say Y here.
1572 1537
1573 config FHANDLE 1538 config FHANDLE
1574 bool "open by fhandle syscalls" if EX 1539 bool "open by fhandle syscalls" if EXPERT
1575 select EXPORTFS 1540 select EXPORTFS
1576 default y 1541 default y
1577 help 1542 help
1578 If you say Y here, a user level pro 1543 If you say Y here, a user level program will be able to map
1579 file names to handle and then later 1544 file names to handle and then later use the handle for
1580 different file system operations. T 1545 different file system operations. This is useful in implementing
1581 userspace file servers, which now t 1546 userspace file servers, which now track files using handles instead
1582 of names. The handle would remain t 1547 of names. The handle would remain the same even if file names
1583 get renamed. Enables open_by_handle 1548 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
1584 syscalls. 1549 syscalls.
1585 1550
1586 config POSIX_TIMERS 1551 config POSIX_TIMERS
1587 bool "Posix Clocks & timers" if EXPER 1552 bool "Posix Clocks & timers" if EXPERT
1588 default y 1553 default y
1589 help 1554 help
1590 This includes native support for PO 1555 This includes native support for POSIX timers to the kernel.
1591 Some embedded systems have no use f 1556 Some embedded systems have no use for them and therefore they
1592 can be configured out to reduce the 1557 can be configured out to reduce the size of the kernel image.
1593 1558
1594 When this option is disabled, the f 1559 When this option is disabled, the following syscalls won't be
1595 available: timer_create, timer_gett 1560 available: timer_create, timer_gettime: timer_getoverrun,
1596 timer_settime, timer_delete, clock_ 1561 timer_settime, timer_delete, clock_adjtime, getitimer,
1597 setitimer, alarm. Furthermore, the 1562 setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
1598 clock_getres and clock_nanosleep sy 1563 clock_getres and clock_nanosleep syscalls will be limited to
1599 CLOCK_REALTIME, CLOCK_MONOTONIC and 1564 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
1600 1565
1601 If unsure say y. 1566 If unsure say y.
1602 1567
1603 config PRINTK 1568 config PRINTK
1604 default y 1569 default y
1605 bool "Enable support for printk" if E 1570 bool "Enable support for printk" if EXPERT
1606 select IRQ_WORK 1571 select IRQ_WORK
1607 help 1572 help
1608 This option enables normal printk s 1573 This option enables normal printk support. Removing it
1609 eliminates most of the message stri 1574 eliminates most of the message strings from the kernel image
1610 and makes the kernel more or less s 1575 and makes the kernel more or less silent. As this makes it
1611 very difficult to diagnose system p 1576 very difficult to diagnose system problems, saying N here is
1612 strongly discouraged. 1577 strongly discouraged.
1613 1578
1614 config BUG 1579 config BUG
1615 bool "BUG() support" if EXPERT 1580 bool "BUG() support" if EXPERT
1616 default y 1581 default y
1617 help 1582 help
1618 Disabling this option eliminates su 1583 Disabling this option eliminates support for BUG and WARN, reducing
1619 the size of your kernel image and p 1584 the size of your kernel image and potentially quietly ignoring
1620 numerous fatal conditions. You shou 1585 numerous fatal conditions. You should only consider disabling this
1621 option for embedded systems with no 1586 option for embedded systems with no facilities for reporting errors.
1622 Just say Y. 1587 Just say Y.
1623 1588
1624 config ELF_CORE 1589 config ELF_CORE
1625 depends on COREDUMP 1590 depends on COREDUMP
1626 default y 1591 default y
1627 bool "Enable ELF core dumps" if EXPER 1592 bool "Enable ELF core dumps" if EXPERT
1628 help 1593 help
1629 Enable support for generating core 1594 Enable support for generating core dumps. Disabling saves about 4k.
1630 1595
1631 1596
1632 config PCSPKR_PLATFORM 1597 config PCSPKR_PLATFORM
1633 bool "Enable PC-Speaker support" if E 1598 bool "Enable PC-Speaker support" if EXPERT
1634 depends on HAVE_PCSPKR_PLATFORM 1599 depends on HAVE_PCSPKR_PLATFORM
1635 select I8253_LOCK 1600 select I8253_LOCK
1636 default y 1601 default y
1637 help 1602 help
1638 This option allows to disable the i 1603 This option allows to disable the internal PC-Speaker
1639 support, saving some memory. 1604 support, saving some memory.
1640 1605
1641 config BASE_SMALL 1606 config BASE_SMALL
1642 bool "Enable smaller-sized data struc 1607 bool "Enable smaller-sized data structures for core" if EXPERT
1643 help 1608 help
1644 Enabling this option reduces the si 1609 Enabling this option reduces the size of miscellaneous core
1645 kernel data structures. This saves 1610 kernel data structures. This saves memory on small machines,
1646 but may reduce performance. 1611 but may reduce performance.
1647 1612
1648 config FUTEX 1613 config FUTEX
1649 bool "Enable futex support" if EXPERT 1614 bool "Enable futex support" if EXPERT
1650 depends on !(SPARC32 && SMP) 1615 depends on !(SPARC32 && SMP)
1651 default y 1616 default y
1652 imply RT_MUTEXES 1617 imply RT_MUTEXES
1653 help 1618 help
1654 Disabling this option will cause th 1619 Disabling this option will cause the kernel to be built without
1655 support for "fast userspace mutexes 1620 support for "fast userspace mutexes". The resulting kernel may not
1656 run glibc-based applications correc 1621 run glibc-based applications correctly.
1657 1622
1658 config FUTEX_PI 1623 config FUTEX_PI
1659 bool 1624 bool
1660 depends on FUTEX && RT_MUTEXES 1625 depends on FUTEX && RT_MUTEXES
1661 default y 1626 default y
1662 1627
1663 config EPOLL 1628 config EPOLL
1664 bool "Enable eventpoll support" if EX 1629 bool "Enable eventpoll support" if EXPERT
1665 default y 1630 default y
1666 help 1631 help
1667 Disabling this option will cause th 1632 Disabling this option will cause the kernel to be built without
1668 support for epoll family of system 1633 support for epoll family of system calls.
1669 1634
1670 config SIGNALFD 1635 config SIGNALFD
1671 bool "Enable signalfd() system call" 1636 bool "Enable signalfd() system call" if EXPERT
1672 default y 1637 default y
1673 help 1638 help
1674 Enable the signalfd() system call t 1639 Enable the signalfd() system call that allows to receive signals
1675 on a file descriptor. 1640 on a file descriptor.
1676 1641
1677 If unsure, say Y. 1642 If unsure, say Y.
1678 1643
1679 config TIMERFD 1644 config TIMERFD
1680 bool "Enable timerfd() system call" i 1645 bool "Enable timerfd() system call" if EXPERT
1681 default y 1646 default y
1682 help 1647 help
1683 Enable the timerfd() system call th 1648 Enable the timerfd() system call that allows to receive timer
1684 events on a file descriptor. 1649 events on a file descriptor.
1685 1650
1686 If unsure, say Y. 1651 If unsure, say Y.
1687 1652
1688 config EVENTFD 1653 config EVENTFD
1689 bool "Enable eventfd() system call" i 1654 bool "Enable eventfd() system call" if EXPERT
1690 default y 1655 default y
1691 help 1656 help
1692 Enable the eventfd() system call th 1657 Enable the eventfd() system call that allows to receive both
1693 kernel notification (ie. KAIO) or u 1658 kernel notification (ie. KAIO) or userspace notifications.
1694 1659
1695 If unsure, say Y. 1660 If unsure, say Y.
1696 1661
1697 config SHMEM 1662 config SHMEM
1698 bool "Use full shmem filesystem" if E 1663 bool "Use full shmem filesystem" if EXPERT
1699 default y 1664 default y
1700 depends on MMU 1665 depends on MMU
1701 help 1666 help
1702 The shmem is an internal filesystem 1667 The shmem is an internal filesystem used to manage shared memory.
1703 It is backed by swap and manages re 1668 It is backed by swap and manages resource limits. It is also exported
1704 to userspace as tmpfs if TMPFS is e 1669 to userspace as tmpfs if TMPFS is enabled. Disabling this
1705 option replaces shmem and tmpfs wit 1670 option replaces shmem and tmpfs with the much simpler ramfs code,
1706 which may be appropriate on small s 1671 which may be appropriate on small systems without swap.
1707 1672
1708 config AIO 1673 config AIO
1709 bool "Enable AIO support" if EXPERT 1674 bool "Enable AIO support" if EXPERT
1710 default y 1675 default y
1711 help 1676 help
1712 This option enables POSIX asynchron 1677 This option enables POSIX asynchronous I/O which may by used
1713 by some high performance threaded a 1678 by some high performance threaded applications. Disabling
1714 this option saves about 7k. 1679 this option saves about 7k.
1715 1680
1716 config IO_URING 1681 config IO_URING
1717 bool "Enable IO uring support" if EXP 1682 bool "Enable IO uring support" if EXPERT
1718 select IO_WQ 1683 select IO_WQ
1719 default y 1684 default y
1720 help 1685 help
1721 This option enables support for the 1686 This option enables support for the io_uring interface, enabling
1722 applications to submit and complete 1687 applications to submit and complete IO through submission and
1723 completion rings that are shared be 1688 completion rings that are shared between the kernel and application.
1724 1689
1725 config GCOV_PROFILE_URING <<
1726 bool "Enable GCOV profiling on the io <<
1727 depends on GCOV_KERNEL <<
1728 help <<
1729 Enable GCOV profiling on the io_uri <<
1730 code coverage testing. <<
1731 <<
1732 If unsure, say N. <<
1733 <<
1734 Note that this will have a negative <<
1735 the io_uring subsystem, hence this <<
1736 specific test purposes. <<
1737 <<
1738 config ADVISE_SYSCALLS 1690 config ADVISE_SYSCALLS
1739 bool "Enable madvise/fadvise syscalls 1691 bool "Enable madvise/fadvise syscalls" if EXPERT
1740 default y 1692 default y
1741 help 1693 help
1742 This option enables the madvise and 1694 This option enables the madvise and fadvise syscalls, used by
1743 applications to advise the kernel a 1695 applications to advise the kernel about their future memory or file
1744 usage, improving performance. If bu 1696 usage, improving performance. If building an embedded system where no
1745 applications use these syscalls, yo 1697 applications use these syscalls, you can disable this option to save
1746 space. 1698 space.
1747 1699
1748 config MEMBARRIER 1700 config MEMBARRIER
1749 bool "Enable membarrier() system call 1701 bool "Enable membarrier() system call" if EXPERT
1750 default y 1702 default y
1751 help 1703 help
1752 Enable the membarrier() system call 1704 Enable the membarrier() system call that allows issuing memory
1753 barriers across all running threads 1705 barriers across all running threads, which can be used to distribute
1754 the cost of user-space memory barri 1706 the cost of user-space memory barriers asymmetrically by transforming
1755 pairs of memory barriers into pairs 1707 pairs of memory barriers into pairs consisting of membarrier() and a
1756 compiler barrier. 1708 compiler barrier.
1757 1709
1758 If unsure, say Y. 1710 If unsure, say Y.
1759 1711
1760 config KCMP 1712 config KCMP
1761 bool "Enable kcmp() system call" if E 1713 bool "Enable kcmp() system call" if EXPERT
1762 help 1714 help
1763 Enable the kernel resource comparis 1715 Enable the kernel resource comparison system call. It provides
1764 user-space with the ability to comp 1716 user-space with the ability to compare two processes to see if they
1765 share a common resource, such as a 1717 share a common resource, such as a file descriptor or even virtual
1766 memory space. 1718 memory space.
1767 1719
1768 If unsure, say N. 1720 If unsure, say N.
1769 1721
1770 config RSEQ 1722 config RSEQ
1771 bool "Enable rseq() system call" if E 1723 bool "Enable rseq() system call" if EXPERT
1772 default y 1724 default y
1773 depends on HAVE_RSEQ 1725 depends on HAVE_RSEQ
1774 select MEMBARRIER 1726 select MEMBARRIER
1775 help 1727 help
1776 Enable the restartable sequences sy 1728 Enable the restartable sequences system call. It provides a
1777 user-space cache for the current CP 1729 user-space cache for the current CPU number value, which
1778 speeds up getting the current CPU n 1730 speeds up getting the current CPU number from user-space,
1779 as well as an ABI to speed up user- 1731 as well as an ABI to speed up user-space operations on
1780 per-CPU data. 1732 per-CPU data.
1781 1733
1782 If unsure, say Y. 1734 If unsure, say Y.
1783 1735
1784 config DEBUG_RSEQ 1736 config DEBUG_RSEQ
1785 default n 1737 default n
1786 bool "Enable debugging of rseq() syst 1738 bool "Enable debugging of rseq() system call" if EXPERT
1787 depends on RSEQ && DEBUG_KERNEL 1739 depends on RSEQ && DEBUG_KERNEL
1788 help 1740 help
1789 Enable extra debugging checks for t 1741 Enable extra debugging checks for the rseq system call.
1790 1742
1791 If unsure, say N. 1743 If unsure, say N.
1792 1744
1793 config CACHESTAT_SYSCALL 1745 config CACHESTAT_SYSCALL
1794 bool "Enable cachestat() system call" 1746 bool "Enable cachestat() system call" if EXPERT
1795 default y 1747 default y
1796 help 1748 help
1797 Enable the cachestat system call, w 1749 Enable the cachestat system call, which queries the page cache
1798 statistics of a file (number of cac 1750 statistics of a file (number of cached pages, dirty pages,
1799 pages marked for writeback, (recent 1751 pages marked for writeback, (recently) evicted pages).
1800 1752
1801 If unsure say Y here. 1753 If unsure say Y here.
1802 1754
1803 config PC104 1755 config PC104
1804 bool "PC/104 support" if EXPERT 1756 bool "PC/104 support" if EXPERT
1805 help 1757 help
1806 Expose PC/104 form factor device dr 1758 Expose PC/104 form factor device drivers and options available for
1807 selection and configuration. Enable 1759 selection and configuration. Enable this option if your target
1808 machine has a PC/104 bus. 1760 machine has a PC/104 bus.
1809 1761
1810 config KALLSYMS 1762 config KALLSYMS
1811 bool "Load all symbols for debugging/ 1763 bool "Load all symbols for debugging/ksymoops" if EXPERT
1812 default y 1764 default y
1813 help 1765 help
1814 Say Y here to let the kernel print 1766 Say Y here to let the kernel print out symbolic crash information and
1815 symbolic stack backtraces. This inc 1767 symbolic stack backtraces. This increases the size of the kernel
1816 somewhat, as all symbols have to be 1768 somewhat, as all symbols have to be loaded into the kernel image.
1817 1769
1818 config KALLSYMS_SELFTEST 1770 config KALLSYMS_SELFTEST
1819 bool "Test the basic functions and pe 1771 bool "Test the basic functions and performance of kallsyms"
1820 depends on KALLSYMS 1772 depends on KALLSYMS
1821 default n 1773 default n
1822 help 1774 help
1823 Test the basic functions and perfor 1775 Test the basic functions and performance of some interfaces, such as
1824 kallsyms_lookup_name. It also calcu 1776 kallsyms_lookup_name. It also calculates the compression rate of the
1825 kallsyms compression algorithm for 1777 kallsyms compression algorithm for the current symbol set.
1826 1778
1827 Start self-test automatically after 1779 Start self-test automatically after system startup. Suggest executing
1828 "dmesg | grep kallsyms_selftest" to 1780 "dmesg | grep kallsyms_selftest" to collect test results. "finish" is
1829 displayed in the last line, indicat 1781 displayed in the last line, indicating that the test is complete.
1830 1782
1831 config KALLSYMS_ALL 1783 config KALLSYMS_ALL
1832 bool "Include all symbols in kallsyms 1784 bool "Include all symbols in kallsyms"
1833 depends on DEBUG_KERNEL && KALLSYMS 1785 depends on DEBUG_KERNEL && KALLSYMS
1834 help 1786 help
1835 Normally kallsyms only contains the 1787 Normally kallsyms only contains the symbols of functions for nicer
1836 OOPS messages and backtraces (i.e., 1788 OOPS messages and backtraces (i.e., symbols from the text and inittext
1837 sections). This is sufficient for m 1789 sections). This is sufficient for most cases. And only if you want to
1838 enable kernel live patching, or oth 1790 enable kernel live patching, or other less common use cases (e.g.,
1839 when a debugger is used) all symbol 1791 when a debugger is used) all symbols are required (i.e., names of
1840 variables from the data sections, e 1792 variables from the data sections, etc).
1841 1793
1842 This option makes sure that all sym 1794 This option makes sure that all symbols are loaded into the kernel
1843 image (i.e., symbols from all secti 1795 image (i.e., symbols from all sections) in cost of increased kernel
1844 size (depending on the kernel confi 1796 size (depending on the kernel configuration, it may be 300KiB or
1845 something like this). 1797 something like this).
1846 1798
1847 Say N unless you really need all sy 1799 Say N unless you really need all symbols, or kernel live patching.
1848 1800
1849 config KALLSYMS_ABSOLUTE_PERCPU 1801 config KALLSYMS_ABSOLUTE_PERCPU
1850 bool 1802 bool
1851 depends on KALLSYMS 1803 depends on KALLSYMS
1852 default X86_64 && SMP 1804 default X86_64 && SMP
1853 1805
1854 # end of the "standard kernel features (exper 1806 # end of the "standard kernel features (expert users)" menu
1855 1807
1856 config ARCH_HAS_MEMBARRIER_CALLBACKS 1808 config ARCH_HAS_MEMBARRIER_CALLBACKS
1857 bool 1809 bool
1858 1810
1859 config ARCH_HAS_MEMBARRIER_SYNC_CORE 1811 config ARCH_HAS_MEMBARRIER_SYNC_CORE
1860 bool 1812 bool
1861 1813
1862 config HAVE_PERF_EVENTS 1814 config HAVE_PERF_EVENTS
1863 bool 1815 bool
1864 help 1816 help
1865 See tools/perf/design.txt for detai 1817 See tools/perf/design.txt for details.
1866 1818
1867 config GUEST_PERF_EVENTS 1819 config GUEST_PERF_EVENTS
1868 bool 1820 bool
1869 depends on HAVE_PERF_EVENTS 1821 depends on HAVE_PERF_EVENTS
1870 1822
1871 config PERF_USE_VMALLOC 1823 config PERF_USE_VMALLOC
1872 bool 1824 bool
1873 help 1825 help
1874 See tools/perf/design.txt for detai 1826 See tools/perf/design.txt for details
1875 1827
1876 menu "Kernel Performance Events And Counters" 1828 menu "Kernel Performance Events And Counters"
1877 1829
1878 config PERF_EVENTS 1830 config PERF_EVENTS
1879 bool "Kernel performance events and c 1831 bool "Kernel performance events and counters"
1880 default y if PROFILING 1832 default y if PROFILING
1881 depends on HAVE_PERF_EVENTS 1833 depends on HAVE_PERF_EVENTS
1882 select IRQ_WORK 1834 select IRQ_WORK
1883 help 1835 help
1884 Enable kernel support for various p 1836 Enable kernel support for various performance events provided
1885 by software and hardware. 1837 by software and hardware.
1886 1838
1887 Software events are supported eithe 1839 Software events are supported either built-in or via the
1888 use of generic tracepoints. 1840 use of generic tracepoints.
1889 1841
1890 Most modern CPUs support performanc 1842 Most modern CPUs support performance events via performance
1891 counter registers. These registers 1843 counter registers. These registers count the number of certain
1892 types of hw events: such as instruc 1844 types of hw events: such as instructions executed, cachemisses
1893 suffered, or branches mis-predicted 1845 suffered, or branches mis-predicted - without slowing down the
1894 kernel or applications. These regis 1846 kernel or applications. These registers can also trigger interrupts
1895 when a threshold number of events h 1847 when a threshold number of events have passed - and can thus be
1896 used to profile the code that runs 1848 used to profile the code that runs on that CPU.
1897 1849
1898 The Linux Performance Event subsyst 1850 The Linux Performance Event subsystem provides an abstraction of
1899 these software and hardware event c 1851 these software and hardware event capabilities, available via a
1900 system call and used by the "perf" 1852 system call and used by the "perf" utility in tools/perf/. It
1901 provides per task and per CPU count 1853 provides per task and per CPU counters, and it provides event
1902 capabilities on top of those. 1854 capabilities on top of those.
1903 1855
1904 Say Y if unsure. 1856 Say Y if unsure.
1905 1857
1906 config DEBUG_PERF_USE_VMALLOC 1858 config DEBUG_PERF_USE_VMALLOC
1907 default n 1859 default n
1908 bool "Debug: use vmalloc to back perf 1860 bool "Debug: use vmalloc to back perf mmap() buffers"
1909 depends on PERF_EVENTS && DEBUG_KERNE 1861 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
1910 select PERF_USE_VMALLOC 1862 select PERF_USE_VMALLOC
1911 help 1863 help
1912 Use vmalloc memory to back perf mma 1864 Use vmalloc memory to back perf mmap() buffers.
1913 1865
1914 Mostly useful for debugging the vma 1866 Mostly useful for debugging the vmalloc code on platforms
1915 that don't require it. 1867 that don't require it.
1916 1868
1917 Say N if unsure. 1869 Say N if unsure.
1918 1870
1919 endmenu 1871 endmenu
1920 1872
1921 config SYSTEM_DATA_VERIFICATION 1873 config SYSTEM_DATA_VERIFICATION
1922 def_bool n 1874 def_bool n
1923 select SYSTEM_TRUSTED_KEYRING 1875 select SYSTEM_TRUSTED_KEYRING
1924 select KEYS 1876 select KEYS
1925 select CRYPTO 1877 select CRYPTO
1926 select CRYPTO_RSA 1878 select CRYPTO_RSA
1927 select ASYMMETRIC_KEY_TYPE 1879 select ASYMMETRIC_KEY_TYPE
1928 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 1880 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1929 select ASN1 1881 select ASN1
1930 select OID_REGISTRY 1882 select OID_REGISTRY
1931 select X509_CERTIFICATE_PARSER 1883 select X509_CERTIFICATE_PARSER
1932 select PKCS7_MESSAGE_PARSER 1884 select PKCS7_MESSAGE_PARSER
1933 help 1885 help
1934 Provide PKCS#7 message verification 1886 Provide PKCS#7 message verification using the contents of the system
1935 trusted keyring to provide public k 1887 trusted keyring to provide public keys. This then can be used for
1936 module verification, kexec image ve 1888 module verification, kexec image verification and firmware blob
1937 verification. 1889 verification.
1938 1890
1939 config PROFILING 1891 config PROFILING
1940 bool "Profiling support" 1892 bool "Profiling support"
1941 help 1893 help
1942 Say Y here to enable the extended p 1894 Say Y here to enable the extended profiling support mechanisms used
1943 by profilers. 1895 by profilers.
1944 1896
1945 config RUST 1897 config RUST
1946 bool "Rust support" 1898 bool "Rust support"
1947 depends on HAVE_RUST 1899 depends on HAVE_RUST
1948 depends on RUST_IS_AVAILABLE 1900 depends on RUST_IS_AVAILABLE
>> 1901 depends on !CFI_CLANG
1949 depends on !MODVERSIONS 1902 depends on !MODVERSIONS
1950 depends on !GCC_PLUGIN_RANDSTRUCT !! 1903 depends on !GCC_PLUGINS
1951 depends on !RANDSTRUCT 1904 depends on !RANDSTRUCT
>> 1905 depends on !SHADOW_CALL_STACK
1952 depends on !DEBUG_INFO_BTF || PAHOLE_ 1906 depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
1953 depends on !CFI_CLANG || HAVE_CFI_ICA <<
1954 select CFI_ICALL_NORMALIZE_INTEGERS i <<
1955 depends on !CALL_PADDING || RUSTC_VER <<
1956 depends on !KASAN_SW_TAGS <<
1957 depends on !(MITIGATION_RETHUNK && KA <<
1958 help 1907 help
1959 Enables Rust support in the kernel. 1908 Enables Rust support in the kernel.
1960 1909
1961 This allows other Rust-related opti 1910 This allows other Rust-related options, like drivers written in Rust,
1962 to be selected. 1911 to be selected.
1963 1912
1964 It is also required to be able to l 1913 It is also required to be able to load external kernel modules
1965 written in Rust. 1914 written in Rust.
1966 1915
1967 See Documentation/rust/ for more in 1916 See Documentation/rust/ for more information.
1968 1917
1969 If unsure, say N. 1918 If unsure, say N.
1970 1919
1971 config RUSTC_VERSION_TEXT 1920 config RUSTC_VERSION_TEXT
1972 string 1921 string
1973 depends on RUST 1922 depends on RUST
1974 default "$(RUSTC_VERSION_TEXT)" !! 1923 default "$(shell,$(RUSTC) --version 2>/dev/null)"
1975 help <<
1976 See `CC_VERSION_TEXT`. <<
1977 1924
1978 config BINDGEN_VERSION_TEXT 1925 config BINDGEN_VERSION_TEXT
1979 string 1926 string
1980 depends on RUST 1927 depends on RUST
1981 # The dummy parameter `workaround-for 1928 # The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0
1982 # (https://github.com/rust-lang/rust- 1929 # (https://github.com/rust-lang/rust-bindgen/pull/2678). It can be removed when
1983 # the minimum version is upgraded pas 1930 # the minimum version is upgraded past that (0.69.1 already fixed the issue).
1984 default "$(shell,$(BINDGEN) --version 1931 default "$(shell,$(BINDGEN) --version workaround-for-0.69.0 2>/dev/null)"
1985 1932
1986 # 1933 #
1987 # Place an empty function call at each tracep 1934 # Place an empty function call at each tracepoint site. Can be
1988 # dynamically changed for a probe function. 1935 # dynamically changed for a probe function.
1989 # 1936 #
1990 config TRACEPOINTS 1937 config TRACEPOINTS
1991 bool 1938 bool
1992 1939
1993 source "kernel/Kconfig.kexec" 1940 source "kernel/Kconfig.kexec"
1994 1941
1995 endmenu # General setup 1942 endmenu # General setup
1996 1943
1997 source "arch/Kconfig" 1944 source "arch/Kconfig"
1998 1945
1999 config RT_MUTEXES 1946 config RT_MUTEXES
2000 bool 1947 bool
2001 default y if PREEMPT_RT 1948 default y if PREEMPT_RT
2002 1949
2003 config MODULE_SIG_FORMAT 1950 config MODULE_SIG_FORMAT
2004 def_bool n 1951 def_bool n
2005 select SYSTEM_DATA_VERIFICATION 1952 select SYSTEM_DATA_VERIFICATION
2006 1953
2007 source "kernel/module/Kconfig" 1954 source "kernel/module/Kconfig"
2008 1955
2009 config INIT_ALL_POSSIBLE 1956 config INIT_ALL_POSSIBLE
2010 bool 1957 bool
2011 help 1958 help
2012 Back when each arch used to define 1959 Back when each arch used to define their own cpu_online_mask and
2013 cpu_possible_mask, some of them cho 1960 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
2014 with all 1s, and others with all 0s 1961 with all 1s, and others with all 0s. When they were centralised,
2015 it was better to provide this optio 1962 it was better to provide this option than to break all the archs
2016 and have several arch maintainers p 1963 and have several arch maintainers pursuing me down dark alleys.
2017 1964
2018 source "block/Kconfig" 1965 source "block/Kconfig"
2019 1966
2020 config PREEMPT_NOTIFIERS 1967 config PREEMPT_NOTIFIERS
2021 bool 1968 bool
2022 1969
2023 config PADATA 1970 config PADATA
2024 depends on SMP 1971 depends on SMP
2025 bool 1972 bool
2026 1973
2027 config ASN1 1974 config ASN1
2028 tristate 1975 tristate
2029 help 1976 help
2030 Build a simple ASN.1 grammar compil 1977 Build a simple ASN.1 grammar compiler that produces a bytecode output
2031 that can be interpreted by the ASN. 1978 that can be interpreted by the ASN.1 stream decoder and used to
2032 inform it as to what tags are to be 1979 inform it as to what tags are to be expected in a stream and what
2033 functions to call on what tags. 1980 functions to call on what tags.
2034 1981
2035 source "kernel/Kconfig.locks" 1982 source "kernel/Kconfig.locks"
2036 1983
2037 config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 1984 config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
2038 bool 1985 bool
2039 1986
2040 config ARCH_HAS_PREPARE_SYNC_CORE_CMD 1987 config ARCH_HAS_PREPARE_SYNC_CORE_CMD
2041 bool 1988 bool
2042 1989
2043 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 1990 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
2044 bool 1991 bool
2045 1992
2046 # It may be useful for an architecture to ove 1993 # It may be useful for an architecture to override the definitions of the
2047 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() ma 1994 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h>
2048 # and the COMPAT_ variants in <linux/compat.h 1995 # and the COMPAT_ variants in <linux/compat.h>, in particular to use a
2049 # different calling convention for syscalls. 1996 # different calling convention for syscalls. They can also override the
2050 # macros for not-implemented syscalls in kern 1997 # macros for not-implemented syscalls in kernel/sys_ni.c and
2051 # kernel/time/posix-stubs.c. All these overri 1998 # kernel/time/posix-stubs.c. All these overrides need to be available in
2052 # <asm/syscall_wrapper.h>. 1999 # <asm/syscall_wrapper.h>.
2053 config ARCH_HAS_SYSCALL_WRAPPER 2000 config ARCH_HAS_SYSCALL_WRAPPER
2054 def_bool n 2001 def_bool n
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