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 <<
96 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id <<
97 config GCC_ASM_GOTO_OUTPUT_BROKEN <<
98 bool <<
99 depends on CC_IS_GCC <<
100 default y if GCC_VERSION < 110500 <<
101 default y if GCC_VERSION >= 120000 && <<
102 default y if GCC_VERSION >= 130000 && <<
103 <<
104 config CC_HAS_ASM_GOTO_OUTPUT 84 config CC_HAS_ASM_GOTO_OUTPUT
105 def_bool y !! 85 def_bool $(success,echo 'int foo(int x) { asm goto ("": "=r"(x) ::: bar); return x; bar: return 0; }' | $(CC) -x c - -c -o /dev/null)
106 depends on !GCC_ASM_GOTO_OUTPUT_BROKEN <<
107 depends on $(success,echo 'int foo(int <<
108 86
109 config CC_HAS_ASM_GOTO_TIED_OUTPUT 87 config CC_HAS_ASM_GOTO_TIED_OUTPUT
110 depends on CC_HAS_ASM_GOTO_OUTPUT 88 depends on CC_HAS_ASM_GOTO_OUTPUT
111 # Detect buggy gcc and clang, fixed in 89 # Detect buggy gcc and clang, fixed in gcc-11 clang-14.
112 def_bool $(success,echo 'int foo(int * 90 def_bool $(success,echo 'int foo(int *x) { asm goto (".long (%l[bar]) - .": "+m"(*x) ::: bar); return *x; bar: return 0; }' | $CC -x c - -c -o /dev/null)
113 91
>> 92 config GCC_ASM_GOTO_OUTPUT_WORKAROUND
>> 93 bool
>> 94 depends on CC_IS_GCC && CC_HAS_ASM_GOTO_OUTPUT
>> 95 # Fixed in GCC 14, 13.3, 12.4 and 11.5
>> 96 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113921
>> 97 default y if GCC_VERSION < 110500
>> 98 default y if GCC_VERSION >= 120000 && GCC_VERSION < 120400
>> 99 default y if GCC_VERSION >= 130000 && GCC_VERSION < 130300
>> 100
114 config TOOLS_SUPPORT_RELR 101 config TOOLS_SUPPORT_RELR
115 def_bool $(success,env "CC=$(CC)" "LD= 102 def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh)
116 103
117 config CC_HAS_ASM_INLINE 104 config CC_HAS_ASM_INLINE
118 def_bool $(success,echo 'void foo(void 105 def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null)
119 106
120 config CC_HAS_NO_PROFILE_FN_ATTR 107 config CC_HAS_NO_PROFILE_FN_ATTR
121 def_bool $(success,echo '__attribute__ 108 def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror)
122 109
123 config PAHOLE_VERSION 110 config PAHOLE_VERSION
124 int 111 int
125 default $(shell,$(srctree)/scripts/pah 112 default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE))
126 113
127 config CONSTRUCTORS 114 config CONSTRUCTORS
128 bool 115 bool
129 116
130 config IRQ_WORK 117 config IRQ_WORK
131 def_bool y if SMP !! 118 bool
132 119
133 config BUILDTIME_TABLE_SORT 120 config BUILDTIME_TABLE_SORT
134 bool 121 bool
135 122
136 config THREAD_INFO_IN_TASK 123 config THREAD_INFO_IN_TASK
137 bool 124 bool
138 help 125 help
139 Select this to move thread_info off 126 Select this to move thread_info off the stack into task_struct. To
140 make this work, an arch will need to 127 make this work, an arch will need to remove all thread_info fields
141 except flags and fix any runtime bug 128 except flags and fix any runtime bugs.
142 129
143 One subtle change that will be neede 130 One subtle change that will be needed is to use try_get_task_stack()
144 and put_task_stack() in save_thread_ 131 and put_task_stack() in save_thread_stack_tsk() and get_wchan().
145 132
146 menu "General setup" 133 menu "General setup"
147 134
148 config BROKEN 135 config BROKEN
149 bool 136 bool
150 137
151 config BROKEN_ON_SMP 138 config BROKEN_ON_SMP
152 bool 139 bool
153 depends on BROKEN || !SMP 140 depends on BROKEN || !SMP
154 default y 141 default y
155 142
156 config INIT_ENV_ARG_LIMIT 143 config INIT_ENV_ARG_LIMIT
157 int 144 int
158 default 32 if !UML 145 default 32 if !UML
159 default 128 if UML 146 default 128 if UML
160 help 147 help
161 Maximum of each of the number of arg 148 Maximum of each of the number of arguments and environment
162 variables passed to init from the ke 149 variables passed to init from the kernel command line.
163 150
164 config COMPILE_TEST 151 config COMPILE_TEST
165 bool "Compile also drivers which will 152 bool "Compile also drivers which will not load"
166 depends on HAS_IOMEM 153 depends on HAS_IOMEM
167 help 154 help
168 Some drivers can be compiled on a di 155 Some drivers can be compiled on a different platform than they are
169 intended to be run on. Despite they 156 intended to be run on. Despite they cannot be loaded there (or even
170 when they load they cannot be used d 157 when they load they cannot be used due to missing HW support),
171 developers still, opposing to distri 158 developers still, opposing to distributors, might want to build such
172 drivers to compile-test them. 159 drivers to compile-test them.
173 160
174 If you are a developer and want to b 161 If you are a developer and want to build everything available, say Y
175 here. If you are a user/distributor, 162 here. If you are a user/distributor, say N here to exclude useless
176 drivers to be distributed. 163 drivers to be distributed.
177 164
178 config WERROR 165 config WERROR
179 bool "Compile the kernel with warnings 166 bool "Compile the kernel with warnings as errors"
180 default COMPILE_TEST 167 default COMPILE_TEST
181 help 168 help
182 A kernel build should not cause any 169 A kernel build should not cause any compiler warnings, and this
183 enables the '-Werror' (for C) and '- 170 enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags
184 to enforce that rule by default. Cer 171 to enforce that rule by default. Certain warnings from other tools
185 such as the linker may be upgraded t 172 such as the linker may be upgraded to errors with this option as
186 well. 173 well.
187 174
188 However, if you have a new (or very 175 However, if you have a new (or very old) compiler or linker with odd
189 and unusual warnings, or you have so 176 and unusual warnings, or you have some architecture with problems,
190 you may need to disable this config 177 you may need to disable this config option in order to
191 successfully build the kernel. 178 successfully build the kernel.
192 179
193 If in doubt, say Y. 180 If in doubt, say Y.
194 181
195 config UAPI_HEADER_TEST 182 config UAPI_HEADER_TEST
196 bool "Compile test UAPI headers" 183 bool "Compile test UAPI headers"
197 depends on HEADERS_INSTALL && CC_CAN_L 184 depends on HEADERS_INSTALL && CC_CAN_LINK
198 help 185 help
199 Compile test headers exported to use 186 Compile test headers exported to user-space to ensure they are
200 self-contained, i.e. compilable as s 187 self-contained, i.e. compilable as standalone units.
201 188
202 If you are a developer or tester and 189 If you are a developer or tester and want to ensure the exported
203 headers are self-contained, say Y he 190 headers are self-contained, say Y here. Otherwise, choose N.
204 191
205 config LOCALVERSION 192 config LOCALVERSION
206 string "Local version - append to kern 193 string "Local version - append to kernel release"
207 help 194 help
208 Append an extra string to the end of 195 Append an extra string to the end of your kernel version.
209 This will show up when you type unam 196 This will show up when you type uname, for example.
210 The string you set here will be appe 197 The string you set here will be appended after the contents of
211 any files with a filename matching l 198 any files with a filename matching localversion* in your
212 object and source tree, in that orde 199 object and source tree, in that order. Your total string can
213 be a maximum of 64 characters. 200 be a maximum of 64 characters.
214 201
215 config LOCALVERSION_AUTO 202 config LOCALVERSION_AUTO
216 bool "Automatically append version inf 203 bool "Automatically append version information to the version string"
217 default y 204 default y
218 depends on !COMPILE_TEST 205 depends on !COMPILE_TEST
219 help 206 help
220 This will try to automatically deter 207 This will try to automatically determine if the current tree is a
221 release tree by looking for git tags 208 release tree by looking for git tags that belong to the current
222 top of tree revision. 209 top of tree revision.
223 210
224 A string of the format -gxxxxxxxx wi 211 A string of the format -gxxxxxxxx will be added to the localversion
225 if a git-based tree is found. The s 212 if a git-based tree is found. The string generated by this will be
226 appended after any matching localver 213 appended after any matching localversion* files, and after the value
227 set in CONFIG_LOCALVERSION. 214 set in CONFIG_LOCALVERSION.
228 215
229 (The actual string used here is the 216 (The actual string used here is the first 12 characters produced
230 by running the command: 217 by running the command:
231 218
232 $ git rev-parse --verify HEAD 219 $ git rev-parse --verify HEAD
233 220
234 which is done within the script "scr 221 which is done within the script "scripts/setlocalversion".)
235 222
236 config BUILD_SALT 223 config BUILD_SALT
237 string "Build ID Salt" 224 string "Build ID Salt"
238 default "" 225 default ""
239 help 226 help
240 The build ID is used to link binarie 227 The build ID is used to link binaries and their debug info. Setting
241 this option will use the value in th 228 this option will use the value in the calculation of the build id.
242 This is mostly useful for distributi 229 This is mostly useful for distributions which want to ensure the
243 build is unique between builds. It's 230 build is unique between builds. It's safe to leave the default.
244 231
245 config HAVE_KERNEL_GZIP 232 config HAVE_KERNEL_GZIP
246 bool 233 bool
247 234
248 config HAVE_KERNEL_BZIP2 235 config HAVE_KERNEL_BZIP2
249 bool 236 bool
250 237
251 config HAVE_KERNEL_LZMA 238 config HAVE_KERNEL_LZMA
252 bool 239 bool
253 240
254 config HAVE_KERNEL_XZ 241 config HAVE_KERNEL_XZ
255 bool 242 bool
256 243
257 config HAVE_KERNEL_LZO 244 config HAVE_KERNEL_LZO
258 bool 245 bool
259 246
260 config HAVE_KERNEL_LZ4 247 config HAVE_KERNEL_LZ4
261 bool 248 bool
262 249
263 config HAVE_KERNEL_ZSTD 250 config HAVE_KERNEL_ZSTD
264 bool 251 bool
265 252
266 config HAVE_KERNEL_UNCOMPRESSED 253 config HAVE_KERNEL_UNCOMPRESSED
267 bool 254 bool
268 255
269 choice 256 choice
270 prompt "Kernel compression mode" 257 prompt "Kernel compression mode"
271 default KERNEL_GZIP 258 default KERNEL_GZIP
272 depends on HAVE_KERNEL_GZIP || HAVE_KE 259 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 260 help
274 The linux kernel is a kind of self-e 261 The linux kernel is a kind of self-extracting executable.
275 Several compression algorithms are a 262 Several compression algorithms are available, which differ
276 in efficiency, compression and decom 263 in efficiency, compression and decompression speed.
277 Compression speed is only relevant w 264 Compression speed is only relevant when building a kernel.
278 Decompression speed is relevant at e 265 Decompression speed is relevant at each boot.
279 266
280 If you have any problems with bzip2 267 If you have any problems with bzip2 or lzma compressed
281 kernels, mail me (Alain Knaff) <alain 268 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
282 version of this functionality (bzip2 269 version of this functionality (bzip2 only), for 2.4, was
283 supplied by Christian Ludwig) 270 supplied by Christian Ludwig)
284 271
285 High compression options are mostly 272 High compression options are mostly useful for users, who
286 are low on disk space (embedded syst 273 are low on disk space (embedded systems), but for whom ram
287 size matters less. 274 size matters less.
288 275
289 If in doubt, select 'gzip' 276 If in doubt, select 'gzip'
290 277
291 config KERNEL_GZIP 278 config KERNEL_GZIP
292 bool "Gzip" 279 bool "Gzip"
293 depends on HAVE_KERNEL_GZIP 280 depends on HAVE_KERNEL_GZIP
294 help 281 help
295 The old and tried gzip compression. 282 The old and tried gzip compression. It provides a good balance
296 between compression ratio and decomp 283 between compression ratio and decompression speed.
297 284
298 config KERNEL_BZIP2 285 config KERNEL_BZIP2
299 bool "Bzip2" 286 bool "Bzip2"
300 depends on HAVE_KERNEL_BZIP2 287 depends on HAVE_KERNEL_BZIP2
301 help 288 help
302 Its compression ratio and speed is i 289 Its compression ratio and speed is intermediate.
303 Decompression speed is slowest among 290 Decompression speed is slowest among the choices. The kernel
304 size is about 10% smaller with bzip2 291 size is about 10% smaller with bzip2, in comparison to gzip.
305 Bzip2 uses a large amount of memory. 292 Bzip2 uses a large amount of memory. For modern kernels you
306 will need at least 8MB RAM or more f 293 will need at least 8MB RAM or more for booting.
307 294
308 config KERNEL_LZMA 295 config KERNEL_LZMA
309 bool "LZMA" 296 bool "LZMA"
310 depends on HAVE_KERNEL_LZMA 297 depends on HAVE_KERNEL_LZMA
311 help 298 help
312 This compression algorithm's ratio i 299 This compression algorithm's ratio is best. Decompression speed
313 is between gzip and bzip2. Compress 300 is between gzip and bzip2. Compression is slowest.
314 The kernel size is about 33% smaller 301 The kernel size is about 33% smaller with LZMA in comparison to gzip.
315 302
316 config KERNEL_XZ 303 config KERNEL_XZ
317 bool "XZ" 304 bool "XZ"
318 depends on HAVE_KERNEL_XZ 305 depends on HAVE_KERNEL_XZ
319 help 306 help
320 XZ uses the LZMA2 algorithm and inst 307 XZ uses the LZMA2 algorithm and instruction set specific
321 BCJ filters which can improve compre 308 BCJ filters which can improve compression ratio of executable
322 code. The size of the kernel is abou 309 code. The size of the kernel is about 30% smaller with XZ in
323 comparison to gzip. On architectures 310 comparison to gzip. On architectures for which there is a BCJ
324 filter (i386, x86_64, ARM, ARM64, RI !! 311 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
325 and SPARC), XZ will create a few per !! 312 will create a few percent smaller kernel than plain LZMA.
326 plain LZMA. <<
327 313
328 The speed is about the same as with 314 The speed is about the same as with LZMA: The decompression
329 speed of XZ is better than that of b 315 speed of XZ is better than that of bzip2 but worse than gzip
330 and LZO. Compression is slow. 316 and LZO. Compression is slow.
331 317
332 config KERNEL_LZO 318 config KERNEL_LZO
333 bool "LZO" 319 bool "LZO"
334 depends on HAVE_KERNEL_LZO 320 depends on HAVE_KERNEL_LZO
335 help 321 help
336 Its compression ratio is the poorest 322 Its compression ratio is the poorest among the choices. The kernel
337 size is about 10% bigger than gzip; 323 size is about 10% bigger than gzip; however its speed
338 (both compression and decompression) 324 (both compression and decompression) is the fastest.
339 325
340 config KERNEL_LZ4 326 config KERNEL_LZ4
341 bool "LZ4" 327 bool "LZ4"
342 depends on HAVE_KERNEL_LZ4 328 depends on HAVE_KERNEL_LZ4
343 help 329 help
344 LZ4 is an LZ77-type compressor with 330 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
345 A preliminary version of LZ4 de/comp 331 A preliminary version of LZ4 de/compression tool is available at
346 <https://code.google.com/p/lz4/>. 332 <https://code.google.com/p/lz4/>.
347 333
348 Its compression ratio is worse than 334 Its compression ratio is worse than LZO. The size of the kernel
349 is about 8% bigger than LZO. But the 335 is about 8% bigger than LZO. But the decompression speed is
350 faster than LZO. 336 faster than LZO.
351 337
352 config KERNEL_ZSTD 338 config KERNEL_ZSTD
353 bool "ZSTD" 339 bool "ZSTD"
354 depends on HAVE_KERNEL_ZSTD 340 depends on HAVE_KERNEL_ZSTD
355 help 341 help
356 ZSTD is a compression algorithm targ 342 ZSTD is a compression algorithm targeting intermediate compression
357 with fast decompression speed. It wi 343 with fast decompression speed. It will compress better than GZIP and
358 decompress around the same speed as 344 decompress around the same speed as LZO, but slower than LZ4. You
359 will need at least 192 KB RAM or mor 345 will need at least 192 KB RAM or more for booting. The zstd command
360 line tool is required for compressio 346 line tool is required for compression.
361 347
362 config KERNEL_UNCOMPRESSED 348 config KERNEL_UNCOMPRESSED
363 bool "None" 349 bool "None"
364 depends on HAVE_KERNEL_UNCOMPRESSED 350 depends on HAVE_KERNEL_UNCOMPRESSED
365 help 351 help
366 Produce uncompressed kernel image. T 352 Produce uncompressed kernel image. This option is usually not what
367 you want. It is useful for debugging 353 you want. It is useful for debugging the kernel in slow simulation
368 environments, where decompressing an 354 environments, where decompressing and moving the kernel is awfully
369 slow. This option allows early boot 355 slow. This option allows early boot code to skip the decompressor
370 and jump right at uncompressed kerne 356 and jump right at uncompressed kernel image.
371 357
372 endchoice 358 endchoice
373 359
374 config DEFAULT_INIT 360 config DEFAULT_INIT
375 string "Default init path" 361 string "Default init path"
376 default "" 362 default ""
377 help 363 help
378 This option determines the default i 364 This option determines the default init for the system if no init=
379 option is passed on the kernel comma 365 option is passed on the kernel command line. If the requested path is
380 not present, we will still then move 366 not present, we will still then move on to attempting further
381 locations (e.g. /sbin/init, etc). If 367 locations (e.g. /sbin/init, etc). If this is empty, we will just use
382 the fallback list when init= is not 368 the fallback list when init= is not passed.
383 369
384 config DEFAULT_HOSTNAME 370 config DEFAULT_HOSTNAME
385 string "Default hostname" 371 string "Default hostname"
386 default "(none)" 372 default "(none)"
387 help 373 help
388 This option determines the default s 374 This option determines the default system hostname before userspace
389 calls sethostname(2). The kernel tra 375 calls sethostname(2). The kernel traditionally uses "(none)" here,
390 but you may wish to use a different 376 but you may wish to use a different default here to make a minimal
391 system more usable with less configu 377 system more usable with less configuration.
392 378
393 config SYSVIPC 379 config SYSVIPC
394 bool "System V IPC" 380 bool "System V IPC"
395 help 381 help
396 Inter Process Communication is a sui 382 Inter Process Communication is a suite of library functions and
397 system calls which let processes (ru 383 system calls which let processes (running programs) synchronize and
398 exchange information. It is generall 384 exchange information. It is generally considered to be a good thing,
399 and some programs won't run unless y 385 and some programs won't run unless you say Y here. In particular, if
400 you want to run the DOS emulator dos 386 you want to run the DOS emulator dosemu under Linux (read the
401 DOSEMU-HOWTO, available from <http:/ 387 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
402 you'll need to say Y here. 388 you'll need to say Y here.
403 389
404 You can find documentation about IPC 390 You can find documentation about IPC with "info ipc" and also in
405 section 6.4 of the Linux Programmer' 391 section 6.4 of the Linux Programmer's Guide, available from
406 <http://www.tldp.org/guides.html>. 392 <http://www.tldp.org/guides.html>.
407 393
408 config SYSVIPC_SYSCTL 394 config SYSVIPC_SYSCTL
409 bool 395 bool
410 depends on SYSVIPC 396 depends on SYSVIPC
411 depends on SYSCTL 397 depends on SYSCTL
412 default y 398 default y
413 399
414 config SYSVIPC_COMPAT 400 config SYSVIPC_COMPAT
415 def_bool y 401 def_bool y
416 depends on COMPAT && SYSVIPC 402 depends on COMPAT && SYSVIPC
417 403
418 config POSIX_MQUEUE 404 config POSIX_MQUEUE
419 bool "POSIX Message Queues" 405 bool "POSIX Message Queues"
420 depends on NET 406 depends on NET
421 help 407 help
422 POSIX variant of message queues is a 408 POSIX variant of message queues is a part of IPC. In POSIX message
423 queues every message has a priority 409 queues every message has a priority which decides about succession
424 of receiving it by a process. If you 410 of receiving it by a process. If you want to compile and run
425 programs written e.g. for Solaris wi 411 programs written e.g. for Solaris with use of its POSIX message
426 queues (functions mq_*) say Y here. 412 queues (functions mq_*) say Y here.
427 413
428 POSIX message queues are visible as 414 POSIX message queues are visible as a filesystem called 'mqueue'
429 and can be mounted somewhere if you 415 and can be mounted somewhere if you want to do filesystem
430 operations on message queues. 416 operations on message queues.
431 417
432 If unsure, say Y. 418 If unsure, say Y.
433 419
434 config POSIX_MQUEUE_SYSCTL 420 config POSIX_MQUEUE_SYSCTL
435 bool 421 bool
436 depends on POSIX_MQUEUE 422 depends on POSIX_MQUEUE
437 depends on SYSCTL 423 depends on SYSCTL
438 default y 424 default y
439 425
440 config WATCH_QUEUE 426 config WATCH_QUEUE
441 bool "General notification queue" 427 bool "General notification queue"
442 default n 428 default n
443 help 429 help
444 430
445 This is a general notification queue 431 This is a general notification queue for the kernel to pass events to
446 userspace by splicing them into pipe 432 userspace by splicing them into pipes. It can be used in conjunction
447 with watches for key/keyring change 433 with watches for key/keyring change notifications and device
448 notifications. 434 notifications.
449 435
450 See Documentation/core-api/watch_que 436 See Documentation/core-api/watch_queue.rst
451 437
452 config CROSS_MEMORY_ATTACH 438 config CROSS_MEMORY_ATTACH
453 bool "Enable process_vm_readv/writev s 439 bool "Enable process_vm_readv/writev syscalls"
454 depends on MMU 440 depends on MMU
455 default y 441 default y
456 help 442 help
457 Enabling this option adds the system 443 Enabling this option adds the system calls process_vm_readv and
458 process_vm_writev which allow a proc 444 process_vm_writev which allow a process with the correct privileges
459 to directly read from or write to an 445 to directly read from or write to another process' address space.
460 See the man page for more details. 446 See the man page for more details.
461 447
462 config USELIB 448 config USELIB
463 bool "uselib syscall (for libc5 and ea 449 bool "uselib syscall (for libc5 and earlier)"
464 default ALPHA || M68K || SPARC 450 default ALPHA || M68K || SPARC
465 help 451 help
466 This option enables the uselib sysca 452 This option enables the uselib syscall, a system call used in the
467 dynamic linker from libc5 and earlie 453 dynamic linker from libc5 and earlier. glibc does not use this
468 system call. If you intend to run p 454 system call. If you intend to run programs built on libc5 or
469 earlier, you may need to enable this 455 earlier, you may need to enable this syscall. Current systems
470 running glibc can safely disable thi 456 running glibc can safely disable this.
471 457
472 config AUDIT 458 config AUDIT
473 bool "Auditing support" 459 bool "Auditing support"
474 depends on NET 460 depends on NET
475 help 461 help
476 Enable auditing infrastructure that 462 Enable auditing infrastructure that can be used with another
477 kernel subsystem, such as SELinux (w 463 kernel subsystem, such as SELinux (which requires this for
478 logging of avc messages output). Sy 464 logging of avc messages output). System call auditing is included
479 on architectures which support it. 465 on architectures which support it.
480 466
481 config HAVE_ARCH_AUDITSYSCALL 467 config HAVE_ARCH_AUDITSYSCALL
482 bool 468 bool
483 469
484 config AUDITSYSCALL 470 config AUDITSYSCALL
485 def_bool y 471 def_bool y
486 depends on AUDIT && HAVE_ARCH_AUDITSYS 472 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
487 select FSNOTIFY 473 select FSNOTIFY
488 474
489 source "kernel/irq/Kconfig" 475 source "kernel/irq/Kconfig"
490 source "kernel/time/Kconfig" 476 source "kernel/time/Kconfig"
491 source "kernel/bpf/Kconfig" 477 source "kernel/bpf/Kconfig"
492 source "kernel/Kconfig.preempt" 478 source "kernel/Kconfig.preempt"
493 479
494 menu "CPU/Task time and stats accounting" 480 menu "CPU/Task time and stats accounting"
495 481
496 config VIRT_CPU_ACCOUNTING 482 config VIRT_CPU_ACCOUNTING
497 bool 483 bool
498 484
499 choice 485 choice
500 prompt "Cputime accounting" 486 prompt "Cputime accounting"
501 default TICK_CPU_ACCOUNTING 487 default TICK_CPU_ACCOUNTING
502 488
503 # Kind of a stub config for the pure tick base 489 # Kind of a stub config for the pure tick based cputime accounting
504 config TICK_CPU_ACCOUNTING 490 config TICK_CPU_ACCOUNTING
505 bool "Simple tick based cputime accoun 491 bool "Simple tick based cputime accounting"
506 depends on !S390 && !NO_HZ_FULL 492 depends on !S390 && !NO_HZ_FULL
507 help 493 help
508 This is the basic tick based cputime 494 This is the basic tick based cputime accounting that maintains
509 statistics about user, system and id 495 statistics about user, system and idle time spent on per jiffies
510 granularity. 496 granularity.
511 497
512 If unsure, say Y. 498 If unsure, say Y.
513 499
514 config VIRT_CPU_ACCOUNTING_NATIVE 500 config VIRT_CPU_ACCOUNTING_NATIVE
515 bool "Deterministic task and CPU time 501 bool "Deterministic task and CPU time accounting"
516 depends on HAVE_VIRT_CPU_ACCOUNTING && 502 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
517 select VIRT_CPU_ACCOUNTING 503 select VIRT_CPU_ACCOUNTING
518 help 504 help
519 Select this option to enable more ac 505 Select this option to enable more accurate task and CPU time
520 accounting. This is done by reading 506 accounting. This is done by reading a CPU counter on each
521 kernel entry and exit and on transit 507 kernel entry and exit and on transitions within the kernel
522 between system, softirq and hardirq 508 between system, softirq and hardirq state, so there is a
523 small performance impact. In the ca 509 small performance impact. In the case of s390 or IBM POWER > 5,
524 this also enables accounting of stol 510 this also enables accounting of stolen time on logically-partitioned
525 systems. 511 systems.
526 512
527 config VIRT_CPU_ACCOUNTING_GEN 513 config VIRT_CPU_ACCOUNTING_GEN
528 bool "Full dynticks CPU time accountin 514 bool "Full dynticks CPU time accounting"
529 depends on HAVE_CONTEXT_TRACKING_USER 515 depends on HAVE_CONTEXT_TRACKING_USER
530 depends on HAVE_VIRT_CPU_ACCOUNTING_GE 516 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
531 depends on GENERIC_CLOCKEVENTS 517 depends on GENERIC_CLOCKEVENTS
532 select VIRT_CPU_ACCOUNTING 518 select VIRT_CPU_ACCOUNTING
533 select CONTEXT_TRACKING_USER 519 select CONTEXT_TRACKING_USER
534 help 520 help
535 Select this option to enable task an 521 Select this option to enable task and CPU time accounting on full
536 dynticks systems. This accounting is 522 dynticks systems. This accounting is implemented by watching every
537 kernel-user boundaries using the con 523 kernel-user boundaries using the context tracking subsystem.
538 The accounting is thus performed at 524 The accounting is thus performed at the expense of some significant
539 overhead. 525 overhead.
540 526
541 For now this is only useful if you a 527 For now this is only useful if you are working on the full
542 dynticks subsystem development. 528 dynticks subsystem development.
543 529
544 If unsure, say N. 530 If unsure, say N.
545 531
546 endchoice 532 endchoice
547 533
548 config IRQ_TIME_ACCOUNTING 534 config IRQ_TIME_ACCOUNTING
549 bool "Fine granularity task level IRQ 535 bool "Fine granularity task level IRQ time accounting"
550 depends on HAVE_IRQ_TIME_ACCOUNTING && 536 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
551 help 537 help
552 Select this option to enable fine gr 538 Select this option to enable fine granularity task irq time
553 accounting. This is done by reading 539 accounting. This is done by reading a timestamp on each
554 transitions between softirq and hard 540 transitions between softirq and hardirq state, so there can be a
555 small performance impact. 541 small performance impact.
556 542
557 If in doubt, say N here. 543 If in doubt, say N here.
558 544
559 config HAVE_SCHED_AVG_IRQ 545 config HAVE_SCHED_AVG_IRQ
560 def_bool y 546 def_bool y
561 depends on IRQ_TIME_ACCOUNTING || PARA 547 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING
562 depends on SMP 548 depends on SMP
563 549
564 config SCHED_HW_PRESSURE !! 550 config SCHED_THERMAL_PRESSURE
565 bool 551 bool
566 default y if ARM && ARM_CPU_TOPOLOGY 552 default y if ARM && ARM_CPU_TOPOLOGY
567 default y if ARM64 553 default y if ARM64
568 depends on SMP 554 depends on SMP
569 depends on CPU_FREQ_THERMAL 555 depends on CPU_FREQ_THERMAL
570 help 556 help
571 Select this option to enable HW pres !! 557 Select this option to enable thermal pressure accounting in the
572 scheduler. HW pressure is the value !! 558 scheduler. Thermal pressure is the value conveyed to the scheduler
573 that reflects the reduction in CPU c 559 that reflects the reduction in CPU compute capacity resulted from
574 HW throttling. HW throttling occurs !! 560 thermal throttling. Thermal throttling occurs when the performance of
575 a CPU is capped due to high operatin !! 561 a CPU is capped due to high operating temperatures.
576 562
577 If selected, the scheduler will be a 563 If selected, the scheduler will be able to balance tasks accordingly,
578 i.e. put less load on throttled CPUs 564 i.e. put less load on throttled CPUs than on non/less throttled ones.
579 565
580 This requires the architecture to im 566 This requires the architecture to implement
581 arch_update_hw_pressure() and arch_s !! 567 arch_update_thermal_pressure() and arch_scale_thermal_pressure().
582 568
583 config BSD_PROCESS_ACCT 569 config BSD_PROCESS_ACCT
584 bool "BSD Process Accounting" 570 bool "BSD Process Accounting"
585 depends on MULTIUSER 571 depends on MULTIUSER
586 help 572 help
587 If you say Y here, a user level prog 573 If you say Y here, a user level program will be able to instruct the
588 kernel (via a special system call) t 574 kernel (via a special system call) to write process accounting
589 information to a file: whenever a pr 575 information to a file: whenever a process exits, information about
590 that process will be appended to the 576 that process will be appended to the file by the kernel. The
591 information includes things such as 577 information includes things such as creation time, owning user,
592 command name, memory usage, controll 578 command name, memory usage, controlling terminal etc. (the complete
593 list is in the struct acct in <file: 579 list is in the struct acct in <file:include/linux/acct.h>). It is
594 up to the user level program to do u 580 up to the user level program to do useful things with this
595 information. This is generally a go 581 information. This is generally a good idea, so say Y.
596 582
597 config BSD_PROCESS_ACCT_V3 583 config BSD_PROCESS_ACCT_V3
598 bool "BSD Process Accounting version 3 584 bool "BSD Process Accounting version 3 file format"
599 depends on BSD_PROCESS_ACCT 585 depends on BSD_PROCESS_ACCT
600 default n 586 default n
601 help 587 help
602 If you say Y here, the process accou 588 If you say Y here, the process accounting information is written
603 in a new file format that also logs 589 in a new file format that also logs the process IDs of each
604 process and its parent. Note that th 590 process and its parent. Note that this file format is incompatible
605 with previous v0/v1/v2 file formats, 591 with previous v0/v1/v2 file formats, so you will need updated tools
606 for processing it. A preliminary ver 592 for processing it. A preliminary version of these tools is available
607 at <http://www.gnu.org/software/acct 593 at <http://www.gnu.org/software/acct/>.
608 594
609 config TASKSTATS 595 config TASKSTATS
610 bool "Export task/process statistics t 596 bool "Export task/process statistics through netlink"
611 depends on NET 597 depends on NET
612 depends on MULTIUSER 598 depends on MULTIUSER
613 default n 599 default n
614 help 600 help
615 Export selected statistics for tasks 601 Export selected statistics for tasks/processes through the
616 generic netlink interface. Unlike BS 602 generic netlink interface. Unlike BSD process accounting, the
617 statistics are available during the 603 statistics are available during the lifetime of tasks/processes as
618 responses to commands. Like BSD acco 604 responses to commands. Like BSD accounting, they are sent to user
619 space on task exit. 605 space on task exit.
620 606
621 Say N if unsure. 607 Say N if unsure.
622 608
623 config TASK_DELAY_ACCT 609 config TASK_DELAY_ACCT
624 bool "Enable per-task delay accounting 610 bool "Enable per-task delay accounting"
625 depends on TASKSTATS 611 depends on TASKSTATS
626 select SCHED_INFO 612 select SCHED_INFO
627 help 613 help
628 Collect information on time spent by 614 Collect information on time spent by a task waiting for system
629 resources like cpu, synchronous bloc 615 resources like cpu, synchronous block I/O completion and swapping
630 in pages. Such statistics can help i 616 in pages. Such statistics can help in setting a task's priorities
631 relative to other tasks for cpu, io, 617 relative to other tasks for cpu, io, rss limits etc.
632 618
633 Say N if unsure. 619 Say N if unsure.
634 620
635 config TASK_XACCT 621 config TASK_XACCT
636 bool "Enable extended accounting over 622 bool "Enable extended accounting over taskstats"
637 depends on TASKSTATS 623 depends on TASKSTATS
638 help 624 help
639 Collect extended task accounting dat 625 Collect extended task accounting data and send the data
640 to userland for processing over the 626 to userland for processing over the taskstats interface.
641 627
642 Say N if unsure. 628 Say N if unsure.
643 629
644 config TASK_IO_ACCOUNTING 630 config TASK_IO_ACCOUNTING
645 bool "Enable per-task storage I/O acco 631 bool "Enable per-task storage I/O accounting"
646 depends on TASK_XACCT 632 depends on TASK_XACCT
647 help 633 help
648 Collect information on the number of 634 Collect information on the number of bytes of storage I/O which this
649 task has caused. 635 task has caused.
650 636
651 Say N if unsure. 637 Say N if unsure.
652 638
653 config PSI 639 config PSI
654 bool "Pressure stall information track 640 bool "Pressure stall information tracking"
655 select KERNFS 641 select KERNFS
656 help 642 help
657 Collect metrics that indicate how ov 643 Collect metrics that indicate how overcommitted the CPU, memory,
658 and IO capacity are in the system. 644 and IO capacity are in the system.
659 645
660 If you say Y here, the kernel will c 646 If you say Y here, the kernel will create /proc/pressure/ with the
661 pressure statistics files cpu, memor 647 pressure statistics files cpu, memory, and io. These will indicate
662 the share of walltime in which some 648 the share of walltime in which some or all tasks in the system are
663 delayed due to contention of the res 649 delayed due to contention of the respective resource.
664 650
665 In kernels with cgroup support, cgro 651 In kernels with cgroup support, cgroups (cgroup2 only) will
666 have cpu.pressure, memory.pressure, 652 have cpu.pressure, memory.pressure, and io.pressure files,
667 which aggregate pressure stalls for 653 which aggregate pressure stalls for the grouped tasks only.
668 654
669 For more details see Documentation/a 655 For more details see Documentation/accounting/psi.rst.
670 656
671 Say N if unsure. 657 Say N if unsure.
672 658
673 config PSI_DEFAULT_DISABLED 659 config PSI_DEFAULT_DISABLED
674 bool "Require boot parameter to enable 660 bool "Require boot parameter to enable pressure stall information tracking"
675 default n 661 default n
676 depends on PSI 662 depends on PSI
677 help 663 help
678 If set, pressure stall information t 664 If set, pressure stall information tracking will be disabled
679 per default but can be enabled throu 665 per default but can be enabled through passing psi=1 on the
680 kernel commandline during boot. 666 kernel commandline during boot.
681 667
682 This feature adds some code to the t 668 This feature adds some code to the task wakeup and sleep
683 paths of the scheduler. The overhead 669 paths of the scheduler. The overhead is too low to affect
684 common scheduling-intense workloads 670 common scheduling-intense workloads in practice (such as
685 webservers, memcache), but it does s 671 webservers, memcache), but it does show up in artificial
686 scheduler stress tests, such as hack 672 scheduler stress tests, such as hackbench.
687 673
688 If you are paranoid and not sure wha 674 If you are paranoid and not sure what the kernel will be
689 used for, say Y. 675 used for, say Y.
690 676
691 Say N if unsure. 677 Say N if unsure.
692 678
693 endmenu # "CPU/Task time and stats accounting" 679 endmenu # "CPU/Task time and stats accounting"
694 680
695 config CPU_ISOLATION 681 config CPU_ISOLATION
696 bool "CPU isolation" 682 bool "CPU isolation"
697 depends on SMP || COMPILE_TEST 683 depends on SMP || COMPILE_TEST
698 default y 684 default y
699 help 685 help
700 Make sure that CPUs running critical 686 Make sure that CPUs running critical tasks are not disturbed by
701 any source of "noise" such as unboun 687 any source of "noise" such as unbound workqueues, timers, kthreads...
702 Unbound jobs get offloaded to housek 688 Unbound jobs get offloaded to housekeeping CPUs. This is driven by
703 the "isolcpus=" boot parameter. 689 the "isolcpus=" boot parameter.
704 690
705 Say Y if unsure. 691 Say Y if unsure.
706 692
707 source "kernel/rcu/Kconfig" 693 source "kernel/rcu/Kconfig"
708 694
709 config IKCONFIG 695 config IKCONFIG
710 tristate "Kernel .config support" 696 tristate "Kernel .config support"
711 help 697 help
712 This option enables the complete Lin 698 This option enables the complete Linux kernel ".config" file
713 contents to be saved in the kernel. 699 contents to be saved in the kernel. It provides documentation
714 of which kernel options are used in 700 of which kernel options are used in a running kernel or in an
715 on-disk kernel. This information ca 701 on-disk kernel. This information can be extracted from the kernel
716 image file with the script scripts/e 702 image file with the script scripts/extract-ikconfig and used as
717 input to rebuild the current kernel 703 input to rebuild the current kernel or to build another kernel.
718 It can also be extracted from a runn 704 It can also be extracted from a running kernel by reading
719 /proc/config.gz if enabled (below). 705 /proc/config.gz if enabled (below).
720 706
721 config IKCONFIG_PROC 707 config IKCONFIG_PROC
722 bool "Enable access to .config through 708 bool "Enable access to .config through /proc/config.gz"
723 depends on IKCONFIG && PROC_FS 709 depends on IKCONFIG && PROC_FS
724 help 710 help
725 This option enables access to the ke 711 This option enables access to the kernel configuration file
726 through /proc/config.gz. 712 through /proc/config.gz.
727 713
728 config IKHEADERS 714 config IKHEADERS
729 tristate "Enable kernel headers throug 715 tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz"
730 depends on SYSFS 716 depends on SYSFS
731 help 717 help
732 This option enables access to the in 718 This option enables access to the in-kernel headers that are generated during
733 the build process. These can be used 719 the build process. These can be used to build eBPF tracing programs,
734 or similar programs. If you build t 720 or similar programs. If you build the headers as a module, a module called
735 kheaders.ko is built which can be lo 721 kheaders.ko is built which can be loaded on-demand to get access to headers.
736 722
737 config LOG_BUF_SHIFT 723 config LOG_BUF_SHIFT
738 int "Kernel log buffer size (16 => 64K 724 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
739 range 12 25 725 range 12 25
740 default 17 726 default 17
741 depends on PRINTK 727 depends on PRINTK
742 help 728 help
743 Select the minimal kernel log buffer 729 Select the minimal kernel log buffer size as a power of 2.
744 The final size is affected by LOG_CP 730 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
745 parameter, see below. Any higher siz 731 parameter, see below. Any higher size also might be forced
746 by "log_buf_len" boot parameter. 732 by "log_buf_len" boot parameter.
747 733
748 Examples: 734 Examples:
749 17 => 128 KB 735 17 => 128 KB
750 16 => 64 KB 736 16 => 64 KB
751 15 => 32 KB 737 15 => 32 KB
752 14 => 16 KB 738 14 => 16 KB
753 13 => 8 KB 739 13 => 8 KB
754 12 => 4 KB 740 12 => 4 KB
755 741
756 config LOG_CPU_MAX_BUF_SHIFT 742 config LOG_CPU_MAX_BUF_SHIFT
757 int "CPU kernel log buffer size contri 743 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
758 depends on SMP 744 depends on SMP
759 range 0 21 745 range 0 21
>> 746 default 12 if !BASE_SMALL
760 default 0 if BASE_SMALL 747 default 0 if BASE_SMALL
761 default 12 <<
762 depends on PRINTK 748 depends on PRINTK
763 help 749 help
764 This option allows to increase the d 750 This option allows to increase the default ring buffer size
765 according to the number of CPUs. The 751 according to the number of CPUs. The value defines the contribution
766 of each CPU as a power of 2. The use 752 of each CPU as a power of 2. The used space is typically only few
767 lines however it might be much more 753 lines however it might be much more when problems are reported,
768 e.g. backtraces. 754 e.g. backtraces.
769 755
770 The increased size means that a new 756 The increased size means that a new buffer has to be allocated and
771 the original static one is unused. I 757 the original static one is unused. It makes sense only on systems
772 with more CPUs. Therefore this value 758 with more CPUs. Therefore this value is used only when the sum of
773 contributions is greater than the ha 759 contributions is greater than the half of the default kernel ring
774 buffer as defined by LOG_BUF_SHIFT. 760 buffer as defined by LOG_BUF_SHIFT. The default values are set
775 so that more than 16 CPUs are needed 761 so that more than 16 CPUs are needed to trigger the allocation.
776 762
777 Also this option is ignored when "lo 763 Also this option is ignored when "log_buf_len" kernel parameter is
778 used as it forces an exact (power of 764 used as it forces an exact (power of two) size of the ring buffer.
779 765
780 The number of possible CPUs is used 766 The number of possible CPUs is used for this computation ignoring
781 hotplugging making the computation o 767 hotplugging making the computation optimal for the worst case
782 scenario while allowing a simple alg 768 scenario while allowing a simple algorithm to be used from bootup.
783 769
784 Examples shift values and their mean 770 Examples shift values and their meaning:
785 17 => 128 KB for each CPU 771 17 => 128 KB for each CPU
786 16 => 64 KB for each CPU 772 16 => 64 KB for each CPU
787 15 => 32 KB for each CPU 773 15 => 32 KB for each CPU
788 14 => 16 KB for each CPU 774 14 => 16 KB for each CPU
789 13 => 8 KB for each CPU 775 13 => 8 KB for each CPU
790 12 => 4 KB for each CPU 776 12 => 4 KB for each CPU
791 777
792 config PRINTK_INDEX 778 config PRINTK_INDEX
793 bool "Printk indexing debugfs interfac 779 bool "Printk indexing debugfs interface"
794 depends on PRINTK && DEBUG_FS 780 depends on PRINTK && DEBUG_FS
795 help 781 help
796 Add support for indexing of all prin 782 Add support for indexing of all printk formats known at compile time
797 at <debugfs>/printk/index/<module>. 783 at <debugfs>/printk/index/<module>.
798 784
799 This can be used as part of maintain 785 This can be used as part of maintaining daemons which monitor
800 /dev/kmsg, as it permits auditing th 786 /dev/kmsg, as it permits auditing the printk formats present in a
801 kernel, allowing detection of cases 787 kernel, allowing detection of cases where monitored printks are
802 changed or no longer present. 788 changed or no longer present.
803 789
804 There is no additional runtime cost 790 There is no additional runtime cost to printk with this enabled.
805 791
806 # 792 #
807 # Architectures with an unreliable sched_clock 793 # Architectures with an unreliable sched_clock() should select this:
808 # 794 #
809 config HAVE_UNSTABLE_SCHED_CLOCK 795 config HAVE_UNSTABLE_SCHED_CLOCK
810 bool 796 bool
811 797
812 config GENERIC_SCHED_CLOCK 798 config GENERIC_SCHED_CLOCK
813 bool 799 bool
814 800
815 menu "Scheduler features" 801 menu "Scheduler features"
816 802
817 config UCLAMP_TASK 803 config UCLAMP_TASK
818 bool "Enable utilization clamping for 804 bool "Enable utilization clamping for RT/FAIR tasks"
819 depends on CPU_FREQ_GOV_SCHEDUTIL 805 depends on CPU_FREQ_GOV_SCHEDUTIL
820 help 806 help
821 This feature enables the scheduler t 807 This feature enables the scheduler to track the clamped utilization
822 of each CPU based on RUNNABLE tasks 808 of each CPU based on RUNNABLE tasks scheduled on that CPU.
823 809
824 With this option, the user can speci 810 With this option, the user can specify the min and max CPU
825 utilization allowed for RUNNABLE tas 811 utilization allowed for RUNNABLE tasks. The max utilization defines
826 the maximum frequency a task should 812 the maximum frequency a task should use while the min utilization
827 defines the minimum frequency it sho 813 defines the minimum frequency it should use.
828 814
829 Both min and max utilization clamp v 815 Both min and max utilization clamp values are hints to the scheduler,
830 aiming at improving its frequency se 816 aiming at improving its frequency selection policy, but they do not
831 enforce or grant any specific bandwi 817 enforce or grant any specific bandwidth for tasks.
832 818
833 If in doubt, say N. 819 If in doubt, say N.
834 820
835 config UCLAMP_BUCKETS_COUNT 821 config UCLAMP_BUCKETS_COUNT
836 int "Number of supported utilization c 822 int "Number of supported utilization clamp buckets"
837 range 5 20 823 range 5 20
838 default 5 824 default 5
839 depends on UCLAMP_TASK 825 depends on UCLAMP_TASK
840 help 826 help
841 Defines the number of clamp buckets 827 Defines the number of clamp buckets to use. The range of each bucket
842 will be SCHED_CAPACITY_SCALE/UCLAMP_ 828 will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the
843 number of clamp buckets the finer th 829 number of clamp buckets the finer their granularity and the higher
844 the precision of clamping aggregatio 830 the precision of clamping aggregation and tracking at run-time.
845 831
846 For example, with the minimum config 832 For example, with the minimum configuration value we will have 5
847 clamp buckets tracking 20% utilizati 833 clamp buckets tracking 20% utilization each. A 25% boosted tasks will
848 be refcounted in the [20..39]% bucke 834 be refcounted in the [20..39]% bucket and will set the bucket clamp
849 effective value to 25%. 835 effective value to 25%.
850 If a second 30% boosted task should 836 If a second 30% boosted task should be co-scheduled on the same CPU,
851 that task will be refcounted in the 837 that task will be refcounted in the same bucket of the first task and
852 it will boost the bucket clamp effec 838 it will boost the bucket clamp effective value to 30%.
853 The clamp effective value of a bucke 839 The clamp effective value of a bucket is reset to its nominal value
854 (20% in the example above) when ther 840 (20% in the example above) when there are no more tasks refcounted in
855 that bucket. 841 that bucket.
856 842
857 An additional boost/capping margin c 843 An additional boost/capping margin can be added to some tasks. In the
858 example above the 25% task will be b 844 example above the 25% task will be boosted to 30% until it exits the
859 CPU. If that should be considered no 845 CPU. If that should be considered not acceptable on certain systems,
860 it's always possible to reduce the m 846 it's always possible to reduce the margin by increasing the number of
861 clamp buckets to trade off used memo 847 clamp buckets to trade off used memory for run-time tracking
862 precision. 848 precision.
863 849
864 If in doubt, use the default value. 850 If in doubt, use the default value.
865 851
866 endmenu 852 endmenu
867 853
868 # 854 #
869 # For architectures that want to enable the su 855 # For architectures that want to enable the support for NUMA-affine scheduler
870 # balancing logic: 856 # balancing logic:
871 # 857 #
872 config ARCH_SUPPORTS_NUMA_BALANCING 858 config ARCH_SUPPORTS_NUMA_BALANCING
873 bool 859 bool
874 860
875 # 861 #
876 # For architectures that prefer to flush all T 862 # For architectures that prefer to flush all TLBs after a number of pages
877 # are unmapped instead of sending one IPI per 863 # are unmapped instead of sending one IPI per page to flush. The architecture
878 # must provide guarantees on what happens if a 864 # must provide guarantees on what happens if a clean TLB cache entry is
879 # written after the unmap. Details are in mm/r 865 # written after the unmap. Details are in mm/rmap.c near the check for
880 # should_defer_flush. The architecture should 866 # should_defer_flush. The architecture should also consider if the full flush
881 # and the refill costs are offset by the savin 867 # and the refill costs are offset by the savings of sending fewer IPIs.
882 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 868 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
883 bool 869 bool
884 870
885 config CC_HAS_INT128 871 config CC_HAS_INT128
886 def_bool !$(cc-option,$(m64-flag) -D__ 872 def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT
887 873
888 config CC_IMPLICIT_FALLTHROUGH 874 config CC_IMPLICIT_FALLTHROUGH
889 string 875 string
890 default "-Wimplicit-fallthrough=5" if 876 default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5)
891 default "-Wimplicit-fallthrough" if CC 877 default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough)
892 878
893 # Currently, disable gcc-10+ array-bounds glob 879 # Currently, disable gcc-10+ array-bounds globally.
894 # It's still broken in gcc-13, so no upper bou 880 # It's still broken in gcc-13, so no upper bound yet.
895 config GCC10_NO_ARRAY_BOUNDS 881 config GCC10_NO_ARRAY_BOUNDS
896 def_bool y 882 def_bool y
897 883
898 config CC_NO_ARRAY_BOUNDS 884 config CC_NO_ARRAY_BOUNDS
899 bool 885 bool
900 default y if CC_IS_GCC && GCC_VERSION !! 886 default y if CC_IS_GCC && GCC_VERSION >= 100000 && GCC10_NO_ARRAY_BOUNDS
901 887
902 # Currently, disable -Wstringop-overflow for G 888 # Currently, disable -Wstringop-overflow for GCC globally.
903 config GCC_NO_STRINGOP_OVERFLOW 889 config GCC_NO_STRINGOP_OVERFLOW
904 def_bool y 890 def_bool y
905 891
906 config CC_NO_STRINGOP_OVERFLOW 892 config CC_NO_STRINGOP_OVERFLOW
907 bool 893 bool
908 default y if CC_IS_GCC && GCC_NO_STRIN 894 default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW
909 895
910 config CC_STRINGOP_OVERFLOW 896 config CC_STRINGOP_OVERFLOW
911 bool 897 bool
912 default y if CC_IS_GCC && !CC_NO_STRIN 898 default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW
913 899
914 # 900 #
915 # For architectures that know their GCC __int1 901 # For architectures that know their GCC __int128 support is sound
916 # 902 #
917 config ARCH_SUPPORTS_INT128 903 config ARCH_SUPPORTS_INT128
918 bool 904 bool
919 905
920 # For architectures that (ab)use NUMA to repre 906 # For architectures that (ab)use NUMA to represent different memory regions
921 # all cpu-local but of different latencies, su 907 # all cpu-local but of different latencies, such as SuperH.
922 # 908 #
923 config ARCH_WANT_NUMA_VARIABLE_LOCALITY 909 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
924 bool 910 bool
925 911
926 config NUMA_BALANCING 912 config NUMA_BALANCING
927 bool "Memory placement aware NUMA sche 913 bool "Memory placement aware NUMA scheduler"
928 depends on ARCH_SUPPORTS_NUMA_BALANCIN 914 depends on ARCH_SUPPORTS_NUMA_BALANCING
929 depends on !ARCH_WANT_NUMA_VARIABLE_LO 915 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
930 depends on SMP && NUMA && MIGRATION && 916 depends on SMP && NUMA && MIGRATION && !PREEMPT_RT
931 help 917 help
932 This option adds support for automat 918 This option adds support for automatic NUMA aware memory/task placement.
933 The mechanism is quite primitive and 919 The mechanism is quite primitive and is based on migrating memory when
934 it has references to the node the ta 920 it has references to the node the task is running on.
935 921
936 This system will be inactive on UMA 922 This system will be inactive on UMA systems.
937 923
938 config NUMA_BALANCING_DEFAULT_ENABLED 924 config NUMA_BALANCING_DEFAULT_ENABLED
939 bool "Automatically enable NUMA aware 925 bool "Automatically enable NUMA aware memory/task placement"
940 default y 926 default y
941 depends on NUMA_BALANCING 927 depends on NUMA_BALANCING
942 help 928 help
943 If set, automatic NUMA balancing wil 929 If set, automatic NUMA balancing will be enabled if running on a NUMA
944 machine. 930 machine.
945 931
946 config SLAB_OBJ_EXT <<
947 bool <<
948 <<
949 menuconfig CGROUPS 932 menuconfig CGROUPS
950 bool "Control Group support" 933 bool "Control Group support"
951 select KERNFS 934 select KERNFS
952 help 935 help
953 This option adds support for groupin 936 This option adds support for grouping sets of processes together, for
954 use with process control subsystems 937 use with process control subsystems such as Cpusets, CFS, memory
955 controls or device isolation. 938 controls or device isolation.
956 See 939 See
957 - Documentation/scheduler/sche 940 - Documentation/scheduler/sched-design-CFS.rst (CFS)
958 - Documentation/admin-guide/cg 941 - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation
959 and 942 and resource control)
960 943
961 Say N if unsure. 944 Say N if unsure.
962 945
963 if CGROUPS 946 if CGROUPS
964 947
965 config PAGE_COUNTER 948 config PAGE_COUNTER
966 bool 949 bool
967 950
968 config CGROUP_FAVOR_DYNMODS 951 config CGROUP_FAVOR_DYNMODS
969 bool "Favor dynamic modification laten 952 bool "Favor dynamic modification latency reduction by default"
970 help 953 help
971 This option enables the "favordynmod 954 This option enables the "favordynmods" mount option by default
972 which reduces the latencies of dynam 955 which reduces the latencies of dynamic cgroup modifications such
973 as task migrations and controller on 956 as task migrations and controller on/offs at the cost of making
974 hot path operations such as forks an 957 hot path operations such as forks and exits more expensive.
975 958
976 Say N if unsure. 959 Say N if unsure.
977 960
978 config MEMCG 961 config MEMCG
979 bool "Memory controller" 962 bool "Memory controller"
980 select PAGE_COUNTER 963 select PAGE_COUNTER
981 select EVENTFD 964 select EVENTFD
982 select SLAB_OBJ_EXT <<
983 help 965 help
984 Provides control over the memory foo 966 Provides control over the memory footprint of tasks in a cgroup.
985 967
986 config MEMCG_V1 !! 968 config MEMCG_KMEM
987 bool "Legacy cgroup v1 memory controll !! 969 bool
988 depends on MEMCG 970 depends on MEMCG
989 default n !! 971 default y
990 help <<
991 Legacy cgroup v1 memory controller w <<
992 cgroup v2 implementation. The v1 is <<
993 which haven't migrated to the new cg <<
994 do not have any such application the <<
995 this option disabled. <<
996 <<
997 Please note that feature set of the <<
998 going to shrink due to deprecation p <<
999 controller are highly discouraged. <<
1000 <<
1001 Say N if unsure. <<
1002 972
1003 config BLK_CGROUP 973 config BLK_CGROUP
1004 bool "IO controller" 974 bool "IO controller"
1005 depends on BLOCK 975 depends on BLOCK
1006 default n 976 default n
1007 help 977 help
1008 Generic block IO controller cgroup in 978 Generic block IO controller cgroup interface. This is the common
1009 cgroup interface which should be used 979 cgroup interface which should be used by various IO controlling
1010 policies. 980 policies.
1011 981
1012 Currently, CFQ IO scheduler uses it t 982 Currently, CFQ IO scheduler uses it to recognize task groups and
1013 control disk bandwidth allocation (pr 983 control disk bandwidth allocation (proportional time slice allocation)
1014 to such task groups. It is also used 984 to such task groups. It is also used by bio throttling logic in
1015 block layer to implement upper limit 985 block layer to implement upper limit in IO rates on a device.
1016 986
1017 This option only enables generic Bloc 987 This option only enables generic Block IO controller infrastructure.
1018 One needs to also enable actual IO co 988 One needs to also enable actual IO controlling logic/policy. For
1019 enabling proportional weight division 989 enabling proportional weight division of disk bandwidth in CFQ, set
1020 CONFIG_BFQ_GROUP_IOSCHED=y; for enabl 990 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1021 CONFIG_BLK_DEV_THROTTLING=y. 991 CONFIG_BLK_DEV_THROTTLING=y.
1022 992
1023 See Documentation/admin-guide/cgroup- 993 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information.
1024 994
1025 config CGROUP_WRITEBACK 995 config CGROUP_WRITEBACK
1026 bool 996 bool
1027 depends on MEMCG && BLK_CGROUP 997 depends on MEMCG && BLK_CGROUP
1028 default y 998 default y
1029 999
1030 menuconfig CGROUP_SCHED 1000 menuconfig CGROUP_SCHED
1031 bool "CPU controller" 1001 bool "CPU controller"
1032 default n 1002 default n
1033 help 1003 help
1034 This feature lets CPU scheduler rec 1004 This feature lets CPU scheduler recognize task groups and control CPU
1035 bandwidth allocation to such task g 1005 bandwidth allocation to such task groups. It uses cgroups to group
1036 tasks. 1006 tasks.
1037 1007
1038 if CGROUP_SCHED 1008 if CGROUP_SCHED
1039 config GROUP_SCHED_WEIGHT <<
1040 def_bool n <<
1041 <<
1042 config FAIR_GROUP_SCHED 1009 config FAIR_GROUP_SCHED
1043 bool "Group scheduling for SCHED_OTHE 1010 bool "Group scheduling for SCHED_OTHER"
1044 depends on CGROUP_SCHED 1011 depends on CGROUP_SCHED
1045 select GROUP_SCHED_WEIGHT <<
1046 default CGROUP_SCHED 1012 default CGROUP_SCHED
1047 1013
1048 config CFS_BANDWIDTH 1014 config CFS_BANDWIDTH
1049 bool "CPU bandwidth provisioning for 1015 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1050 depends on FAIR_GROUP_SCHED 1016 depends on FAIR_GROUP_SCHED
1051 default n 1017 default n
1052 help 1018 help
1053 This option allows users to define 1019 This option allows users to define CPU bandwidth rates (limits) for
1054 tasks running within the fair group 1020 tasks running within the fair group scheduler. Groups with no limit
1055 set are considered to be unconstrai 1021 set are considered to be unconstrained and will run with no
1056 restriction. 1022 restriction.
1057 See Documentation/scheduler/sched-b 1023 See Documentation/scheduler/sched-bwc.rst for more information.
1058 1024
1059 config RT_GROUP_SCHED 1025 config RT_GROUP_SCHED
1060 bool "Group scheduling for SCHED_RR/F 1026 bool "Group scheduling for SCHED_RR/FIFO"
1061 depends on CGROUP_SCHED 1027 depends on CGROUP_SCHED
1062 default n 1028 default n
1063 help 1029 help
1064 This feature lets you explicitly al 1030 This feature lets you explicitly allocate real CPU bandwidth
1065 to task groups. If enabled, it will 1031 to task groups. If enabled, it will also make it impossible to
1066 schedule realtime tasks for non-roo 1032 schedule realtime tasks for non-root users until you allocate
1067 realtime bandwidth for them. 1033 realtime bandwidth for them.
1068 See Documentation/scheduler/sched-r 1034 See Documentation/scheduler/sched-rt-group.rst for more information.
1069 1035
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 1036 endif #CGROUP_SCHED
1077 1037
1078 config SCHED_MM_CID 1038 config SCHED_MM_CID
1079 def_bool y 1039 def_bool y
1080 depends on SMP && RSEQ 1040 depends on SMP && RSEQ
1081 1041
1082 config UCLAMP_TASK_GROUP 1042 config UCLAMP_TASK_GROUP
1083 bool "Utilization clamping per group 1043 bool "Utilization clamping per group of tasks"
1084 depends on CGROUP_SCHED 1044 depends on CGROUP_SCHED
1085 depends on UCLAMP_TASK 1045 depends on UCLAMP_TASK
1086 default n 1046 default n
1087 help 1047 help
1088 This feature enables the scheduler 1048 This feature enables the scheduler to track the clamped utilization
1089 of each CPU based on RUNNABLE tasks 1049 of each CPU based on RUNNABLE tasks currently scheduled on that CPU.
1090 1050
1091 When this option is enabled, the us 1051 When this option is enabled, the user can specify a min and max
1092 CPU bandwidth which is allowed for 1052 CPU bandwidth which is allowed for each single task in a group.
1093 The max bandwidth allows to clamp t 1053 The max bandwidth allows to clamp the maximum frequency a task
1094 can use, while the min bandwidth al 1054 can use, while the min bandwidth allows to define a minimum
1095 frequency a task will always use. 1055 frequency a task will always use.
1096 1056
1097 When task group based utilization c 1057 When task group based utilization clamping is enabled, an eventually
1098 specified task-specific clamp value 1058 specified task-specific clamp value is constrained by the cgroup
1099 specified clamp value. Both minimum 1059 specified clamp value. Both minimum and maximum task clamping cannot
1100 be bigger than the corresponding cl 1060 be bigger than the corresponding clamping defined at task group level.
1101 1061
1102 If in doubt, say N. 1062 If in doubt, say N.
1103 1063
1104 config CGROUP_PIDS 1064 config CGROUP_PIDS
1105 bool "PIDs controller" 1065 bool "PIDs controller"
1106 help 1066 help
1107 Provides enforcement of process num 1067 Provides enforcement of process number limits in the scope of a
1108 cgroup. Any attempt to fork more pr 1068 cgroup. Any attempt to fork more processes than is allowed in the
1109 cgroup will fail. PIDs are fundamen 1069 cgroup will fail. PIDs are fundamentally a global resource because it
1110 is fairly trivial to reach PID exha 1070 is fairly trivial to reach PID exhaustion before you reach even a
1111 conservative kmemcg limit. As a res 1071 conservative kmemcg limit. As a result, it is possible to grind a
1112 system to halt without being limite 1072 system to halt without being limited by other cgroup policies. The
1113 PIDs controller is designed to stop 1073 PIDs controller is designed to stop this from happening.
1114 1074
1115 It should be noted that organisatio 1075 It should be noted that organisational operations (such as attaching
1116 to a cgroup hierarchy) will *not* b 1076 to a cgroup hierarchy) will *not* be blocked by the PIDs controller,
1117 since the PIDs limit only affects a 1077 since the PIDs limit only affects a process's ability to fork, not to
1118 attach to a cgroup. 1078 attach to a cgroup.
1119 1079
1120 config CGROUP_RDMA 1080 config CGROUP_RDMA
1121 bool "RDMA controller" 1081 bool "RDMA controller"
1122 help 1082 help
1123 Provides enforcement of RDMA resour 1083 Provides enforcement of RDMA resources defined by IB stack.
1124 It is fairly easy for consumers to 1084 It is fairly easy for consumers to exhaust RDMA resources, which
1125 can result into resource unavailabi 1085 can result into resource unavailability to other consumers.
1126 RDMA controller is designed to stop 1086 RDMA controller is designed to stop this from happening.
1127 Attaching processes with active RDM 1087 Attaching processes with active RDMA resources to the cgroup
1128 hierarchy is allowed even if can cr 1088 hierarchy is allowed even if can cross the hierarchy's limit.
1129 1089
1130 config CGROUP_FREEZER 1090 config CGROUP_FREEZER
1131 bool "Freezer controller" 1091 bool "Freezer controller"
1132 help 1092 help
1133 Provides a way to freeze and unfree 1093 Provides a way to freeze and unfreeze all tasks in a
1134 cgroup. 1094 cgroup.
1135 1095
1136 This option affects the ORIGINAL cg 1096 This option affects the ORIGINAL cgroup interface. The cgroup2 memory
1137 controller includes important in-ke 1097 controller includes important in-kernel memory consumers per default.
1138 1098
1139 If you're using cgroup2, say N. 1099 If you're using cgroup2, say N.
1140 1100
1141 config CGROUP_HUGETLB 1101 config CGROUP_HUGETLB
1142 bool "HugeTLB controller" 1102 bool "HugeTLB controller"
1143 depends on HUGETLB_PAGE 1103 depends on HUGETLB_PAGE
1144 select PAGE_COUNTER 1104 select PAGE_COUNTER
1145 default n 1105 default n
1146 help 1106 help
1147 Provides a cgroup controller for Hu 1107 Provides a cgroup controller for HugeTLB pages.
1148 When you enable this, you can put a 1108 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1149 The limit is enforced during page f 1109 The limit is enforced during page fault. Since HugeTLB doesn't
1150 support page reclaim, enforcing the 1110 support page reclaim, enforcing the limit at page fault time implies
1151 that, the application will get SIGB 1111 that, the application will get SIGBUS signal if it tries to access
1152 HugeTLB pages beyond its limit. Thi 1112 HugeTLB pages beyond its limit. This requires the application to know
1153 beforehand how much HugeTLB pages i 1113 beforehand how much HugeTLB pages it would require for its use. The
1154 control group is tracked in the thi 1114 control group is tracked in the third page lru pointer. This means
1155 that we cannot use the controller w 1115 that we cannot use the controller with huge page less than 3 pages.
1156 1116
1157 config CPUSETS 1117 config CPUSETS
1158 bool "Cpuset controller" 1118 bool "Cpuset controller"
1159 depends on SMP 1119 depends on SMP
1160 help 1120 help
1161 This option will let you create and 1121 This option will let you create and manage CPUSETs which
1162 allow dynamically partitioning a sy 1122 allow dynamically partitioning a system into sets of CPUs and
1163 Memory Nodes and assigning tasks to 1123 Memory Nodes and assigning tasks to run only within those sets.
1164 This is primarily useful on large S 1124 This is primarily useful on large SMP or NUMA systems.
1165 1125
1166 Say N if unsure. 1126 Say N if unsure.
1167 1127
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 1128 config PROC_PID_CPUSET
1182 bool "Include legacy /proc/<pid>/cpus 1129 bool "Include legacy /proc/<pid>/cpuset file"
1183 depends on CPUSETS 1130 depends on CPUSETS
1184 default y 1131 default y
1185 1132
1186 config CGROUP_DEVICE 1133 config CGROUP_DEVICE
1187 bool "Device controller" 1134 bool "Device controller"
1188 help 1135 help
1189 Provides a cgroup controller implem 1136 Provides a cgroup controller implementing whitelists for
1190 devices which a process in the cgro 1137 devices which a process in the cgroup can mknod or open.
1191 1138
1192 config CGROUP_CPUACCT 1139 config CGROUP_CPUACCT
1193 bool "Simple CPU accounting controlle 1140 bool "Simple CPU accounting controller"
1194 help 1141 help
1195 Provides a simple controller for mo 1142 Provides a simple controller for monitoring the
1196 total CPU consumed by the tasks in 1143 total CPU consumed by the tasks in a cgroup.
1197 1144
1198 config CGROUP_PERF 1145 config CGROUP_PERF
1199 bool "Perf controller" 1146 bool "Perf controller"
1200 depends on PERF_EVENTS 1147 depends on PERF_EVENTS
1201 help 1148 help
1202 This option extends the perf per-cp 1149 This option extends the perf per-cpu mode to restrict monitoring
1203 to threads which belong to the cgro 1150 to threads which belong to the cgroup specified and run on the
1204 designated cpu. Or this can be use 1151 designated cpu. Or this can be used to have cgroup ID in samples
1205 so that it can monitor performance 1152 so that it can monitor performance events among cgroups.
1206 1153
1207 Say N if unsure. 1154 Say N if unsure.
1208 1155
1209 config CGROUP_BPF 1156 config CGROUP_BPF
1210 bool "Support for eBPF programs attac 1157 bool "Support for eBPF programs attached to cgroups"
1211 depends on BPF_SYSCALL 1158 depends on BPF_SYSCALL
1212 select SOCK_CGROUP_DATA 1159 select SOCK_CGROUP_DATA
1213 help 1160 help
1214 Allow attaching eBPF programs to a 1161 Allow attaching eBPF programs to a cgroup using the bpf(2)
1215 syscall command BPF_PROG_ATTACH. 1162 syscall command BPF_PROG_ATTACH.
1216 1163
1217 In which context these programs are 1164 In which context these programs are accessed depends on the type
1218 of attachment. For instance, progra 1165 of attachment. For instance, programs that are attached using
1219 BPF_CGROUP_INET_INGRESS will be exe 1166 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
1220 inet sockets. 1167 inet sockets.
1221 1168
1222 config CGROUP_MISC 1169 config CGROUP_MISC
1223 bool "Misc resource controller" 1170 bool "Misc resource controller"
1224 default n 1171 default n
1225 help 1172 help
1226 Provides a controller for miscellan 1173 Provides a controller for miscellaneous resources on a host.
1227 1174
1228 Miscellaneous scalar resources are 1175 Miscellaneous scalar resources are the resources on the host system
1229 which cannot be abstracted like the 1176 which cannot be abstracted like the other cgroups. This controller
1230 tracks and limits the miscellaneous 1177 tracks and limits the miscellaneous resources used by a process
1231 attached to a cgroup hierarchy. 1178 attached to a cgroup hierarchy.
1232 1179
1233 For more information, please check 1180 For more information, please check misc cgroup section in
1234 /Documentation/admin-guide/cgroup-v 1181 /Documentation/admin-guide/cgroup-v2.rst.
1235 1182
1236 config CGROUP_DEBUG 1183 config CGROUP_DEBUG
1237 bool "Debug controller" 1184 bool "Debug controller"
1238 default n 1185 default n
1239 depends on DEBUG_KERNEL 1186 depends on DEBUG_KERNEL
1240 help 1187 help
1241 This option enables a simple contro 1188 This option enables a simple controller that exports
1242 debugging information about the cgr 1189 debugging information about the cgroups framework. This
1243 controller is for control cgroup de 1190 controller is for control cgroup debugging only. Its
1244 interfaces are not stable. 1191 interfaces are not stable.
1245 1192
1246 Say N. 1193 Say N.
1247 1194
1248 config SOCK_CGROUP_DATA 1195 config SOCK_CGROUP_DATA
1249 bool 1196 bool
1250 default n 1197 default n
1251 1198
1252 endif # CGROUPS 1199 endif # CGROUPS
1253 1200
1254 menuconfig NAMESPACES 1201 menuconfig NAMESPACES
1255 bool "Namespaces support" if EXPERT 1202 bool "Namespaces support" if EXPERT
1256 depends on MULTIUSER 1203 depends on MULTIUSER
1257 default !EXPERT 1204 default !EXPERT
1258 help 1205 help
1259 Provides the way to make tasks work 1206 Provides the way to make tasks work with different objects using
1260 the same id. For example same IPC i 1207 the same id. For example same IPC id may refer to different objects
1261 or same user id or pid may refer to 1208 or same user id or pid may refer to different tasks when used in
1262 different namespaces. 1209 different namespaces.
1263 1210
1264 if NAMESPACES 1211 if NAMESPACES
1265 1212
1266 config UTS_NS 1213 config UTS_NS
1267 bool "UTS namespace" 1214 bool "UTS namespace"
1268 default y 1215 default y
1269 help 1216 help
1270 In this namespace tasks see differe 1217 In this namespace tasks see different info provided with the
1271 uname() system call 1218 uname() system call
1272 1219
1273 config TIME_NS 1220 config TIME_NS
1274 bool "TIME namespace" 1221 bool "TIME namespace"
1275 depends on GENERIC_VDSO_TIME_NS 1222 depends on GENERIC_VDSO_TIME_NS
1276 default y 1223 default y
1277 help 1224 help
1278 In this namespace boottime and mono 1225 In this namespace boottime and monotonic clocks can be set.
1279 The time will keep going with the s 1226 The time will keep going with the same pace.
1280 1227
1281 config IPC_NS 1228 config IPC_NS
1282 bool "IPC namespace" 1229 bool "IPC namespace"
1283 depends on (SYSVIPC || POSIX_MQUEUE) 1230 depends on (SYSVIPC || POSIX_MQUEUE)
1284 default y 1231 default y
1285 help 1232 help
1286 In this namespace tasks work with I 1233 In this namespace tasks work with IPC ids which correspond to
1287 different IPC objects in different 1234 different IPC objects in different namespaces.
1288 1235
1289 config USER_NS 1236 config USER_NS
1290 bool "User namespace" 1237 bool "User namespace"
1291 default n 1238 default n
1292 help 1239 help
1293 This allows containers, i.e. vserve 1240 This allows containers, i.e. vservers, to use user namespaces
1294 to provide different user info for 1241 to provide different user info for different servers.
1295 1242
1296 When user namespaces are enabled in 1243 When user namespaces are enabled in the kernel it is
1297 recommended that the MEMCG option a 1244 recommended that the MEMCG option also be enabled and that
1298 user-space use the memory control g 1245 user-space use the memory control groups to limit the amount
1299 of memory a memory unprivileged use 1246 of memory a memory unprivileged users can use.
1300 1247
1301 If unsure, say N. 1248 If unsure, say N.
1302 1249
1303 config PID_NS 1250 config PID_NS
1304 bool "PID Namespaces" 1251 bool "PID Namespaces"
1305 default y 1252 default y
1306 help 1253 help
1307 Support process id namespaces. Thi 1254 Support process id namespaces. This allows having multiple
1308 processes with the same pid as long 1255 processes with the same pid as long as they are in different
1309 pid namespaces. This is a building 1256 pid namespaces. This is a building block of containers.
1310 1257
1311 config NET_NS 1258 config NET_NS
1312 bool "Network namespace" 1259 bool "Network namespace"
1313 depends on NET 1260 depends on NET
1314 default y 1261 default y
1315 help 1262 help
1316 Allow user space to create what app 1263 Allow user space to create what appear to be multiple instances
1317 of the network stack. 1264 of the network stack.
1318 1265
1319 endif # NAMESPACES 1266 endif # NAMESPACES
1320 1267
1321 config CHECKPOINT_RESTORE 1268 config CHECKPOINT_RESTORE
1322 bool "Checkpoint/restore support" 1269 bool "Checkpoint/restore support"
1323 depends on PROC_FS 1270 depends on PROC_FS
1324 select PROC_CHILDREN 1271 select PROC_CHILDREN
1325 select KCMP 1272 select KCMP
1326 default n 1273 default n
1327 help 1274 help
1328 Enables additional kernel features 1275 Enables additional kernel features in a sake of checkpoint/restore.
1329 In particular it adds auxiliary prc 1276 In particular it adds auxiliary prctl codes to setup process text,
1330 data and heap segment sizes, and a 1277 data and heap segment sizes, and a few additional /proc filesystem
1331 entries. 1278 entries.
1332 1279
1333 If unsure, say N here. 1280 If unsure, say N here.
1334 1281
1335 config SCHED_AUTOGROUP 1282 config SCHED_AUTOGROUP
1336 bool "Automatic process group schedul 1283 bool "Automatic process group scheduling"
1337 select CGROUPS 1284 select CGROUPS
1338 select CGROUP_SCHED 1285 select CGROUP_SCHED
1339 select FAIR_GROUP_SCHED 1286 select FAIR_GROUP_SCHED
1340 help 1287 help
1341 This option optimizes the scheduler 1288 This option optimizes the scheduler for common desktop workloads by
1342 automatically creating and populati 1289 automatically creating and populating task groups. This separation
1343 of workloads isolates aggressive CP 1290 of workloads isolates aggressive CPU burners (like build jobs) from
1344 desktop applications. Task group a 1291 desktop applications. Task group autogeneration is currently based
1345 upon task session. 1292 upon task session.
1346 1293
1347 config RELAY 1294 config RELAY
1348 bool "Kernel->user space relay suppor 1295 bool "Kernel->user space relay support (formerly relayfs)"
1349 select IRQ_WORK 1296 select IRQ_WORK
1350 help 1297 help
1351 This option enables support for rel 1298 This option enables support for relay interface support in
1352 certain file systems (such as debug 1299 certain file systems (such as debugfs).
1353 It is designed to provide an effici 1300 It is designed to provide an efficient mechanism for tools and
1354 facilities to relay large amounts o 1301 facilities to relay large amounts of data from kernel space to
1355 user space. 1302 user space.
1356 1303
1357 If unsure, say N. 1304 If unsure, say N.
1358 1305
1359 config BLK_DEV_INITRD 1306 config BLK_DEV_INITRD
1360 bool "Initial RAM filesystem and RAM 1307 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1361 help 1308 help
1362 The initial RAM filesystem is a ram 1309 The initial RAM filesystem is a ramfs which is loaded by the
1363 boot loader (loadlin or lilo) and t 1310 boot loader (loadlin or lilo) and that is mounted as root
1364 before the normal boot procedure. I 1311 before the normal boot procedure. It is typically used to
1365 load modules needed to mount the "r 1312 load modules needed to mount the "real" root file system,
1366 etc. See <file:Documentation/admin- 1313 etc. See <file:Documentation/admin-guide/initrd.rst> for details.
1367 1314
1368 If RAM disk support (BLK_DEV_RAM) i 1315 If RAM disk support (BLK_DEV_RAM) is also included, this
1369 also enables initial RAM disk (init 1316 also enables initial RAM disk (initrd) support and adds
1370 15 Kbytes (more on some other archi 1317 15 Kbytes (more on some other architectures) to the kernel size.
1371 1318
1372 If unsure say Y. 1319 If unsure say Y.
1373 1320
1374 if BLK_DEV_INITRD 1321 if BLK_DEV_INITRD
1375 1322
1376 source "usr/Kconfig" 1323 source "usr/Kconfig"
1377 1324
1378 endif 1325 endif
1379 1326
1380 config BOOT_CONFIG 1327 config BOOT_CONFIG
1381 bool "Boot config support" 1328 bool "Boot config support"
1382 select BLK_DEV_INITRD if !BOOT_CONFIG 1329 select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED
1383 help 1330 help
1384 Extra boot config allows system adm 1331 Extra boot config allows system admin to pass a config file as
1385 complemental extension of kernel cm 1332 complemental extension of kernel cmdline when booting.
1386 The boot config file must be attach 1333 The boot config file must be attached at the end of initramfs
1387 with checksum, size and magic word. 1334 with checksum, size and magic word.
1388 See <file:Documentation/admin-guide 1335 See <file:Documentation/admin-guide/bootconfig.rst> for details.
1389 1336
1390 If unsure, say Y. 1337 If unsure, say Y.
1391 1338
1392 config BOOT_CONFIG_FORCE 1339 config BOOT_CONFIG_FORCE
1393 bool "Force unconditional bootconfig 1340 bool "Force unconditional bootconfig processing"
1394 depends on BOOT_CONFIG 1341 depends on BOOT_CONFIG
1395 default y if BOOT_CONFIG_EMBED 1342 default y if BOOT_CONFIG_EMBED
1396 help 1343 help
1397 With this Kconfig option set, BOOT_ 1344 With this Kconfig option set, BOOT_CONFIG processing is carried
1398 out even when the "bootconfig" kern 1345 out even when the "bootconfig" kernel-boot parameter is omitted.
1399 In fact, with this Kconfig option s 1346 In fact, with this Kconfig option set, there is no way to
1400 make the kernel ignore the BOOT_CON 1347 make the kernel ignore the BOOT_CONFIG-supplied kernel-boot
1401 parameters. 1348 parameters.
1402 1349
1403 If unsure, say N. 1350 If unsure, say N.
1404 1351
1405 config BOOT_CONFIG_EMBED 1352 config BOOT_CONFIG_EMBED
1406 bool "Embed bootconfig file in the ke 1353 bool "Embed bootconfig file in the kernel"
1407 depends on BOOT_CONFIG 1354 depends on BOOT_CONFIG
1408 help 1355 help
1409 Embed a bootconfig file given by BO 1356 Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the
1410 kernel. Usually, the bootconfig fil 1357 kernel. Usually, the bootconfig file is loaded with the initrd
1411 image. But if the system doesn't su 1358 image. But if the system doesn't support initrd, this option will
1412 help you by embedding a bootconfig 1359 help you by embedding a bootconfig file while building the kernel.
1413 1360
1414 If unsure, say N. 1361 If unsure, say N.
1415 1362
1416 config BOOT_CONFIG_EMBED_FILE 1363 config BOOT_CONFIG_EMBED_FILE
1417 string "Embedded bootconfig file path 1364 string "Embedded bootconfig file path"
1418 depends on BOOT_CONFIG_EMBED 1365 depends on BOOT_CONFIG_EMBED
1419 help 1366 help
1420 Specify a bootconfig file which wil 1367 Specify a bootconfig file which will be embedded to the kernel.
1421 This bootconfig will be used if the 1368 This bootconfig will be used if there is no initrd or no other
1422 bootconfig in the initrd. 1369 bootconfig in the initrd.
1423 1370
1424 config INITRAMFS_PRESERVE_MTIME 1371 config INITRAMFS_PRESERVE_MTIME
1425 bool "Preserve cpio archive mtimes in 1372 bool "Preserve cpio archive mtimes in initramfs"
1426 default y 1373 default y
1427 help 1374 help
1428 Each entry in an initramfs cpio arc 1375 Each entry in an initramfs cpio archive carries an mtime value. When
1429 enabled, extracted cpio items take 1376 enabled, extracted cpio items take this mtime, with directory mtime
1430 setting deferred until after creati 1377 setting deferred until after creation of any child entries.
1431 1378
1432 If unsure, say Y. 1379 If unsure, say Y.
1433 1380
1434 choice 1381 choice
1435 prompt "Compiler optimization level" 1382 prompt "Compiler optimization level"
1436 default CC_OPTIMIZE_FOR_PERFORMANCE 1383 default CC_OPTIMIZE_FOR_PERFORMANCE
1437 1384
1438 config CC_OPTIMIZE_FOR_PERFORMANCE 1385 config CC_OPTIMIZE_FOR_PERFORMANCE
1439 bool "Optimize for performance (-O2)" 1386 bool "Optimize for performance (-O2)"
1440 help 1387 help
1441 This is the default optimization le 1388 This is the default optimization level for the kernel, building
1442 with the "-O2" compiler flag for be 1389 with the "-O2" compiler flag for best performance and most
1443 helpful compile-time warnings. 1390 helpful compile-time warnings.
1444 1391
1445 config CC_OPTIMIZE_FOR_SIZE 1392 config CC_OPTIMIZE_FOR_SIZE
1446 bool "Optimize for size (-Os)" 1393 bool "Optimize for size (-Os)"
1447 help 1394 help
1448 Choosing this option will pass "-Os 1395 Choosing this option will pass "-Os" to your compiler resulting
1449 in a smaller kernel. 1396 in a smaller kernel.
1450 1397
1451 endchoice 1398 endchoice
1452 1399
1453 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1400 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1454 bool 1401 bool
1455 help 1402 help
1456 This requires that the arch annotat 1403 This requires that the arch annotates or otherwise protects
1457 its external entry points from bein 1404 its external entry points from being discarded. Linker scripts
1458 must also merge .text.*, .data.*, a 1405 must also merge .text.*, .data.*, and .bss.* correctly into
1459 output sections. Care must be taken 1406 output sections. Care must be taken not to pull in unrelated
1460 sections (e.g., '.text.init'). Typi 1407 sections (e.g., '.text.init'). Typically '.' in section names
1461 is used to distinguish them from la 1408 is used to distinguish them from label names / C identifiers.
1462 1409
1463 config LD_DEAD_CODE_DATA_ELIMINATION 1410 config LD_DEAD_CODE_DATA_ELIMINATION
1464 bool "Dead code and data elimination 1411 bool "Dead code and data elimination (EXPERIMENTAL)"
1465 depends on HAVE_LD_DEAD_CODE_DATA_ELI 1412 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1466 depends on EXPERT 1413 depends on EXPERT
1467 depends on $(cc-option,-ffunction-sec 1414 depends on $(cc-option,-ffunction-sections -fdata-sections)
1468 depends on $(ld-option,--gc-sections) 1415 depends on $(ld-option,--gc-sections)
1469 help 1416 help
1470 Enable this if you want to do dead 1417 Enable this if you want to do dead code and data elimination with
1471 the linker by compiling with -ffunc 1418 the linker by compiling with -ffunction-sections -fdata-sections,
1472 and linking with --gc-sections. 1419 and linking with --gc-sections.
1473 1420
1474 This can reduce on disk and in-memo 1421 This can reduce on disk and in-memory size of the kernel
1475 code and static data, particularly 1422 code and static data, particularly for small configs and
1476 on small systems. This has the poss 1423 on small systems. This has the possibility of introducing
1477 silently broken kernel if the requi 1424 silently broken kernel if the required annotations are not
1478 present. This option is not well te 1425 present. This option is not well tested yet, so use at your
1479 own risk. 1426 own risk.
1480 1427
1481 config LD_ORPHAN_WARN 1428 config LD_ORPHAN_WARN
1482 def_bool y 1429 def_bool y
1483 depends on ARCH_WANT_LD_ORPHAN_WARN 1430 depends on ARCH_WANT_LD_ORPHAN_WARN
1484 depends on $(ld-option,--orphan-handl 1431 depends on $(ld-option,--orphan-handling=warn)
1485 depends on $(ld-option,--orphan-handl 1432 depends on $(ld-option,--orphan-handling=error)
1486 1433
1487 config LD_ORPHAN_WARN_LEVEL 1434 config LD_ORPHAN_WARN_LEVEL
1488 string 1435 string
1489 depends on LD_ORPHAN_WARN 1436 depends on LD_ORPHAN_WARN
1490 default "error" if WERROR 1437 default "error" if WERROR
1491 default "warn" 1438 default "warn"
1492 1439
1493 config SYSCTL 1440 config SYSCTL
1494 bool 1441 bool
1495 1442
1496 config HAVE_UID16 1443 config HAVE_UID16
1497 bool 1444 bool
1498 1445
1499 config SYSCTL_EXCEPTION_TRACE 1446 config SYSCTL_EXCEPTION_TRACE
1500 bool 1447 bool
1501 help 1448 help
1502 Enable support for /proc/sys/debug/ 1449 Enable support for /proc/sys/debug/exception-trace.
1503 1450
1504 config SYSCTL_ARCH_UNALIGN_NO_WARN 1451 config SYSCTL_ARCH_UNALIGN_NO_WARN
1505 bool 1452 bool
1506 help 1453 help
1507 Enable support for /proc/sys/kernel 1454 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1508 Allows arch to define/use @no_unali 1455 Allows arch to define/use @no_unaligned_warning to possibly warn
1509 about unaligned access emulation go 1456 about unaligned access emulation going on under the hood.
1510 1457
1511 config SYSCTL_ARCH_UNALIGN_ALLOW 1458 config SYSCTL_ARCH_UNALIGN_ALLOW
1512 bool 1459 bool
1513 help 1460 help
1514 Enable support for /proc/sys/kernel 1461 Enable support for /proc/sys/kernel/unaligned-trap
1515 Allows arches to define/use @unalig 1462 Allows arches to define/use @unaligned_enabled to runtime toggle
1516 the unaligned access emulation. 1463 the unaligned access emulation.
1517 see arch/parisc/kernel/unaligned.c 1464 see arch/parisc/kernel/unaligned.c for reference
1518 1465
1519 config HAVE_PCSPKR_PLATFORM 1466 config HAVE_PCSPKR_PLATFORM
1520 bool 1467 bool
1521 1468
>> 1469 # interpreter that classic socket filters depend on
>> 1470 config BPF
>> 1471 bool
>> 1472 select CRYPTO_LIB_SHA1
>> 1473
1522 menuconfig EXPERT 1474 menuconfig EXPERT
1523 bool "Configure standard kernel featu 1475 bool "Configure standard kernel features (expert users)"
1524 # Unhide debug options, to make the o 1476 # Unhide debug options, to make the on-by-default options visible
1525 select DEBUG_KERNEL 1477 select DEBUG_KERNEL
1526 help 1478 help
1527 This option allows certain base ker 1479 This option allows certain base kernel options and settings
1528 to be disabled or tweaked. This is 1480 to be disabled or tweaked. This is for specialized
1529 environments which can tolerate a " 1481 environments which can tolerate a "non-standard" kernel.
1530 Only use this if you really know wh 1482 Only use this if you really know what you are doing.
1531 1483
1532 config UID16 1484 config UID16
1533 bool "Enable 16-bit UID system calls" 1485 bool "Enable 16-bit UID system calls" if EXPERT
1534 depends on HAVE_UID16 && MULTIUSER 1486 depends on HAVE_UID16 && MULTIUSER
1535 default y 1487 default y
1536 help 1488 help
1537 This enables the legacy 16-bit UID 1489 This enables the legacy 16-bit UID syscall wrappers.
1538 1490
1539 config MULTIUSER 1491 config MULTIUSER
1540 bool "Multiple users, groups and capa 1492 bool "Multiple users, groups and capabilities support" if EXPERT
1541 default y 1493 default y
1542 help 1494 help
1543 This option enables support for non 1495 This option enables support for non-root users, groups and
1544 capabilities. 1496 capabilities.
1545 1497
1546 If you say N here, all processes wi 1498 If you say N here, all processes will run with UID 0, GID 0, and all
1547 possible capabilities. Saying N he 1499 possible capabilities. Saying N here also compiles out support for
1548 system calls related to UIDs, GIDs, 1500 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1549 setgid, and capset. 1501 setgid, and capset.
1550 1502
1551 If unsure, say Y here. 1503 If unsure, say Y here.
1552 1504
1553 config SGETMASK_SYSCALL 1505 config SGETMASK_SYSCALL
1554 bool "sgetmask/ssetmask syscalls supp 1506 bool "sgetmask/ssetmask syscalls support" if EXPERT
1555 default PARISC || M68K || PPC || MIPS !! 1507 def_bool PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH
1556 help 1508 help
1557 sys_sgetmask and sys_ssetmask are o 1509 sys_sgetmask and sys_ssetmask are obsolete system calls
1558 no longer supported in libc but sti 1510 no longer supported in libc but still enabled by default in some
1559 architectures. 1511 architectures.
1560 1512
1561 If unsure, leave the default option 1513 If unsure, leave the default option here.
1562 1514
1563 config SYSFS_SYSCALL 1515 config SYSFS_SYSCALL
1564 bool "Sysfs syscall support" if EXPER 1516 bool "Sysfs syscall support" if EXPERT
1565 default y 1517 default y
1566 help 1518 help
1567 sys_sysfs is an obsolete system cal 1519 sys_sysfs is an obsolete system call no longer supported in libc.
1568 Note that disabling this option is 1520 Note that disabling this option is more secure but might break
1569 compatibility with some systems. 1521 compatibility with some systems.
1570 1522
1571 If unsure say Y here. 1523 If unsure say Y here.
1572 1524
1573 config FHANDLE 1525 config FHANDLE
1574 bool "open by fhandle syscalls" if EX 1526 bool "open by fhandle syscalls" if EXPERT
1575 select EXPORTFS 1527 select EXPORTFS
1576 default y 1528 default y
1577 help 1529 help
1578 If you say Y here, a user level pro 1530 If you say Y here, a user level program will be able to map
1579 file names to handle and then later 1531 file names to handle and then later use the handle for
1580 different file system operations. T 1532 different file system operations. This is useful in implementing
1581 userspace file servers, which now t 1533 userspace file servers, which now track files using handles instead
1582 of names. The handle would remain t 1534 of names. The handle would remain the same even if file names
1583 get renamed. Enables open_by_handle 1535 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
1584 syscalls. 1536 syscalls.
1585 1537
1586 config POSIX_TIMERS 1538 config POSIX_TIMERS
1587 bool "Posix Clocks & timers" if EXPER 1539 bool "Posix Clocks & timers" if EXPERT
1588 default y 1540 default y
1589 help 1541 help
1590 This includes native support for PO 1542 This includes native support for POSIX timers to the kernel.
1591 Some embedded systems have no use f 1543 Some embedded systems have no use for them and therefore they
1592 can be configured out to reduce the 1544 can be configured out to reduce the size of the kernel image.
1593 1545
1594 When this option is disabled, the f 1546 When this option is disabled, the following syscalls won't be
1595 available: timer_create, timer_gett 1547 available: timer_create, timer_gettime: timer_getoverrun,
1596 timer_settime, timer_delete, clock_ 1548 timer_settime, timer_delete, clock_adjtime, getitimer,
1597 setitimer, alarm. Furthermore, the 1549 setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
1598 clock_getres and clock_nanosleep sy 1550 clock_getres and clock_nanosleep syscalls will be limited to
1599 CLOCK_REALTIME, CLOCK_MONOTONIC and 1551 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
1600 1552
1601 If unsure say y. 1553 If unsure say y.
1602 1554
1603 config PRINTK 1555 config PRINTK
1604 default y 1556 default y
1605 bool "Enable support for printk" if E 1557 bool "Enable support for printk" if EXPERT
1606 select IRQ_WORK 1558 select IRQ_WORK
1607 help 1559 help
1608 This option enables normal printk s 1560 This option enables normal printk support. Removing it
1609 eliminates most of the message stri 1561 eliminates most of the message strings from the kernel image
1610 and makes the kernel more or less s 1562 and makes the kernel more or less silent. As this makes it
1611 very difficult to diagnose system p 1563 very difficult to diagnose system problems, saying N here is
1612 strongly discouraged. 1564 strongly discouraged.
1613 1565
1614 config BUG 1566 config BUG
1615 bool "BUG() support" if EXPERT 1567 bool "BUG() support" if EXPERT
1616 default y 1568 default y
1617 help 1569 help
1618 Disabling this option eliminates su 1570 Disabling this option eliminates support for BUG and WARN, reducing
1619 the size of your kernel image and p 1571 the size of your kernel image and potentially quietly ignoring
1620 numerous fatal conditions. You shou 1572 numerous fatal conditions. You should only consider disabling this
1621 option for embedded systems with no 1573 option for embedded systems with no facilities for reporting errors.
1622 Just say Y. 1574 Just say Y.
1623 1575
1624 config ELF_CORE 1576 config ELF_CORE
1625 depends on COREDUMP 1577 depends on COREDUMP
1626 default y 1578 default y
1627 bool "Enable ELF core dumps" if EXPER 1579 bool "Enable ELF core dumps" if EXPERT
1628 help 1580 help
1629 Enable support for generating core 1581 Enable support for generating core dumps. Disabling saves about 4k.
1630 1582
1631 1583
1632 config PCSPKR_PLATFORM 1584 config PCSPKR_PLATFORM
1633 bool "Enable PC-Speaker support" if E 1585 bool "Enable PC-Speaker support" if EXPERT
1634 depends on HAVE_PCSPKR_PLATFORM 1586 depends on HAVE_PCSPKR_PLATFORM
1635 select I8253_LOCK 1587 select I8253_LOCK
1636 default y 1588 default y
1637 help 1589 help
1638 This option allows to disable the i 1590 This option allows to disable the internal PC-Speaker
1639 support, saving some memory. 1591 support, saving some memory.
1640 1592
1641 config BASE_SMALL !! 1593 config BASE_FULL
1642 bool "Enable smaller-sized data struc !! 1594 default y
>> 1595 bool "Enable full-sized data structures for core" if EXPERT
1643 help 1596 help
1644 Enabling this option reduces the si !! 1597 Disabling this option reduces the size of miscellaneous core
1645 kernel data structures. This saves 1598 kernel data structures. This saves memory on small machines,
1646 but may reduce performance. 1599 but may reduce performance.
1647 1600
1648 config FUTEX 1601 config FUTEX
1649 bool "Enable futex support" if EXPERT 1602 bool "Enable futex support" if EXPERT
1650 depends on !(SPARC32 && SMP) 1603 depends on !(SPARC32 && SMP)
1651 default y 1604 default y
1652 imply RT_MUTEXES 1605 imply RT_MUTEXES
1653 help 1606 help
1654 Disabling this option will cause th 1607 Disabling this option will cause the kernel to be built without
1655 support for "fast userspace mutexes 1608 support for "fast userspace mutexes". The resulting kernel may not
1656 run glibc-based applications correc 1609 run glibc-based applications correctly.
1657 1610
1658 config FUTEX_PI 1611 config FUTEX_PI
1659 bool 1612 bool
1660 depends on FUTEX && RT_MUTEXES 1613 depends on FUTEX && RT_MUTEXES
1661 default y 1614 default y
1662 1615
1663 config EPOLL 1616 config EPOLL
1664 bool "Enable eventpoll support" if EX 1617 bool "Enable eventpoll support" if EXPERT
1665 default y 1618 default y
1666 help 1619 help
1667 Disabling this option will cause th 1620 Disabling this option will cause the kernel to be built without
1668 support for epoll family of system 1621 support for epoll family of system calls.
1669 1622
1670 config SIGNALFD 1623 config SIGNALFD
1671 bool "Enable signalfd() system call" 1624 bool "Enable signalfd() system call" if EXPERT
1672 default y 1625 default y
1673 help 1626 help
1674 Enable the signalfd() system call t 1627 Enable the signalfd() system call that allows to receive signals
1675 on a file descriptor. 1628 on a file descriptor.
1676 1629
1677 If unsure, say Y. 1630 If unsure, say Y.
1678 1631
1679 config TIMERFD 1632 config TIMERFD
1680 bool "Enable timerfd() system call" i 1633 bool "Enable timerfd() system call" if EXPERT
1681 default y 1634 default y
1682 help 1635 help
1683 Enable the timerfd() system call th 1636 Enable the timerfd() system call that allows to receive timer
1684 events on a file descriptor. 1637 events on a file descriptor.
1685 1638
1686 If unsure, say Y. 1639 If unsure, say Y.
1687 1640
1688 config EVENTFD 1641 config EVENTFD
1689 bool "Enable eventfd() system call" i 1642 bool "Enable eventfd() system call" if EXPERT
1690 default y 1643 default y
1691 help 1644 help
1692 Enable the eventfd() system call th 1645 Enable the eventfd() system call that allows to receive both
1693 kernel notification (ie. KAIO) or u 1646 kernel notification (ie. KAIO) or userspace notifications.
1694 1647
1695 If unsure, say Y. 1648 If unsure, say Y.
1696 1649
1697 config SHMEM 1650 config SHMEM
1698 bool "Use full shmem filesystem" if E 1651 bool "Use full shmem filesystem" if EXPERT
1699 default y 1652 default y
1700 depends on MMU 1653 depends on MMU
1701 help 1654 help
1702 The shmem is an internal filesystem 1655 The shmem is an internal filesystem used to manage shared memory.
1703 It is backed by swap and manages re 1656 It is backed by swap and manages resource limits. It is also exported
1704 to userspace as tmpfs if TMPFS is e 1657 to userspace as tmpfs if TMPFS is enabled. Disabling this
1705 option replaces shmem and tmpfs wit 1658 option replaces shmem and tmpfs with the much simpler ramfs code,
1706 which may be appropriate on small s 1659 which may be appropriate on small systems without swap.
1707 1660
1708 config AIO 1661 config AIO
1709 bool "Enable AIO support" if EXPERT 1662 bool "Enable AIO support" if EXPERT
1710 default y 1663 default y
1711 help 1664 help
1712 This option enables POSIX asynchron 1665 This option enables POSIX asynchronous I/O which may by used
1713 by some high performance threaded a 1666 by some high performance threaded applications. Disabling
1714 this option saves about 7k. 1667 this option saves about 7k.
1715 1668
1716 config IO_URING 1669 config IO_URING
1717 bool "Enable IO uring support" if EXP 1670 bool "Enable IO uring support" if EXPERT
1718 select IO_WQ 1671 select IO_WQ
1719 default y 1672 default y
1720 help 1673 help
1721 This option enables support for the 1674 This option enables support for the io_uring interface, enabling
1722 applications to submit and complete 1675 applications to submit and complete IO through submission and
1723 completion rings that are shared be 1676 completion rings that are shared between the kernel and application.
1724 1677
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 1678 config ADVISE_SYSCALLS
1739 bool "Enable madvise/fadvise syscalls 1679 bool "Enable madvise/fadvise syscalls" if EXPERT
1740 default y 1680 default y
1741 help 1681 help
1742 This option enables the madvise and 1682 This option enables the madvise and fadvise syscalls, used by
1743 applications to advise the kernel a 1683 applications to advise the kernel about their future memory or file
1744 usage, improving performance. If bu 1684 usage, improving performance. If building an embedded system where no
1745 applications use these syscalls, yo 1685 applications use these syscalls, you can disable this option to save
1746 space. 1686 space.
1747 1687
1748 config MEMBARRIER 1688 config MEMBARRIER
1749 bool "Enable membarrier() system call 1689 bool "Enable membarrier() system call" if EXPERT
1750 default y 1690 default y
1751 help 1691 help
1752 Enable the membarrier() system call 1692 Enable the membarrier() system call that allows issuing memory
1753 barriers across all running threads 1693 barriers across all running threads, which can be used to distribute
1754 the cost of user-space memory barri 1694 the cost of user-space memory barriers asymmetrically by transforming
1755 pairs of memory barriers into pairs 1695 pairs of memory barriers into pairs consisting of membarrier() and a
1756 compiler barrier. 1696 compiler barrier.
1757 1697
1758 If unsure, say Y. 1698 If unsure, say Y.
1759 1699
1760 config KCMP 1700 config KCMP
1761 bool "Enable kcmp() system call" if E 1701 bool "Enable kcmp() system call" if EXPERT
1762 help 1702 help
1763 Enable the kernel resource comparis 1703 Enable the kernel resource comparison system call. It provides
1764 user-space with the ability to comp 1704 user-space with the ability to compare two processes to see if they
1765 share a common resource, such as a 1705 share a common resource, such as a file descriptor or even virtual
1766 memory space. 1706 memory space.
1767 1707
1768 If unsure, say N. 1708 If unsure, say N.
1769 1709
1770 config RSEQ 1710 config RSEQ
1771 bool "Enable rseq() system call" if E 1711 bool "Enable rseq() system call" if EXPERT
1772 default y 1712 default y
1773 depends on HAVE_RSEQ 1713 depends on HAVE_RSEQ
1774 select MEMBARRIER 1714 select MEMBARRIER
1775 help 1715 help
1776 Enable the restartable sequences sy 1716 Enable the restartable sequences system call. It provides a
1777 user-space cache for the current CP 1717 user-space cache for the current CPU number value, which
1778 speeds up getting the current CPU n 1718 speeds up getting the current CPU number from user-space,
1779 as well as an ABI to speed up user- 1719 as well as an ABI to speed up user-space operations on
1780 per-CPU data. 1720 per-CPU data.
1781 1721
1782 If unsure, say Y. 1722 If unsure, say Y.
1783 1723
1784 config DEBUG_RSEQ 1724 config DEBUG_RSEQ
1785 default n 1725 default n
1786 bool "Enable debugging of rseq() syst 1726 bool "Enable debugging of rseq() system call" if EXPERT
1787 depends on RSEQ && DEBUG_KERNEL 1727 depends on RSEQ && DEBUG_KERNEL
1788 help 1728 help
1789 Enable extra debugging checks for t 1729 Enable extra debugging checks for the rseq system call.
1790 1730
1791 If unsure, say N. 1731 If unsure, say N.
1792 1732
1793 config CACHESTAT_SYSCALL 1733 config CACHESTAT_SYSCALL
1794 bool "Enable cachestat() system call" 1734 bool "Enable cachestat() system call" if EXPERT
1795 default y 1735 default y
1796 help 1736 help
1797 Enable the cachestat system call, w 1737 Enable the cachestat system call, which queries the page cache
1798 statistics of a file (number of cac 1738 statistics of a file (number of cached pages, dirty pages,
1799 pages marked for writeback, (recent 1739 pages marked for writeback, (recently) evicted pages).
1800 1740
1801 If unsure say Y here. 1741 If unsure say Y here.
1802 1742
1803 config PC104 1743 config PC104
1804 bool "PC/104 support" if EXPERT 1744 bool "PC/104 support" if EXPERT
1805 help 1745 help
1806 Expose PC/104 form factor device dr 1746 Expose PC/104 form factor device drivers and options available for
1807 selection and configuration. Enable 1747 selection and configuration. Enable this option if your target
1808 machine has a PC/104 bus. 1748 machine has a PC/104 bus.
1809 1749
1810 config KALLSYMS 1750 config KALLSYMS
1811 bool "Load all symbols for debugging/ 1751 bool "Load all symbols for debugging/ksymoops" if EXPERT
1812 default y 1752 default y
1813 help 1753 help
1814 Say Y here to let the kernel print 1754 Say Y here to let the kernel print out symbolic crash information and
1815 symbolic stack backtraces. This inc 1755 symbolic stack backtraces. This increases the size of the kernel
1816 somewhat, as all symbols have to be 1756 somewhat, as all symbols have to be loaded into the kernel image.
1817 1757
1818 config KALLSYMS_SELFTEST 1758 config KALLSYMS_SELFTEST
1819 bool "Test the basic functions and pe 1759 bool "Test the basic functions and performance of kallsyms"
1820 depends on KALLSYMS 1760 depends on KALLSYMS
1821 default n 1761 default n
1822 help 1762 help
1823 Test the basic functions and perfor 1763 Test the basic functions and performance of some interfaces, such as
1824 kallsyms_lookup_name. It also calcu 1764 kallsyms_lookup_name. It also calculates the compression rate of the
1825 kallsyms compression algorithm for 1765 kallsyms compression algorithm for the current symbol set.
1826 1766
1827 Start self-test automatically after 1767 Start self-test automatically after system startup. Suggest executing
1828 "dmesg | grep kallsyms_selftest" to 1768 "dmesg | grep kallsyms_selftest" to collect test results. "finish" is
1829 displayed in the last line, indicat 1769 displayed in the last line, indicating that the test is complete.
1830 1770
1831 config KALLSYMS_ALL 1771 config KALLSYMS_ALL
1832 bool "Include all symbols in kallsyms 1772 bool "Include all symbols in kallsyms"
1833 depends on DEBUG_KERNEL && KALLSYMS 1773 depends on DEBUG_KERNEL && KALLSYMS
1834 help 1774 help
1835 Normally kallsyms only contains the 1775 Normally kallsyms only contains the symbols of functions for nicer
1836 OOPS messages and backtraces (i.e., 1776 OOPS messages and backtraces (i.e., symbols from the text and inittext
1837 sections). This is sufficient for m 1777 sections). This is sufficient for most cases. And only if you want to
1838 enable kernel live patching, or oth 1778 enable kernel live patching, or other less common use cases (e.g.,
1839 when a debugger is used) all symbol 1779 when a debugger is used) all symbols are required (i.e., names of
1840 variables from the data sections, e 1780 variables from the data sections, etc).
1841 1781
1842 This option makes sure that all sym 1782 This option makes sure that all symbols are loaded into the kernel
1843 image (i.e., symbols from all secti 1783 image (i.e., symbols from all sections) in cost of increased kernel
1844 size (depending on the kernel confi 1784 size (depending on the kernel configuration, it may be 300KiB or
1845 something like this). 1785 something like this).
1846 1786
1847 Say N unless you really need all sy 1787 Say N unless you really need all symbols, or kernel live patching.
1848 1788
1849 config KALLSYMS_ABSOLUTE_PERCPU 1789 config KALLSYMS_ABSOLUTE_PERCPU
1850 bool 1790 bool
1851 depends on KALLSYMS 1791 depends on KALLSYMS
1852 default X86_64 && SMP 1792 default X86_64 && SMP
1853 1793
>> 1794 config KALLSYMS_BASE_RELATIVE
>> 1795 bool
>> 1796 depends on KALLSYMS
>> 1797 default y
>> 1798 help
>> 1799 Instead of emitting them as absolute values in the native word size,
>> 1800 emit the symbol references in the kallsyms table as 32-bit entries,
>> 1801 each containing a relative value in the range [base, base + U32_MAX]
>> 1802 or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either
>> 1803 an absolute value in the range [0, S32_MAX] or a relative value in the
>> 1804 range [base, base + S32_MAX], where base is the lowest relative symbol
>> 1805 address encountered in the image.
>> 1806
>> 1807 On 64-bit builds, this reduces the size of the address table by 50%,
>> 1808 but more importantly, it results in entries whose values are build
>> 1809 time constants, and no relocation pass is required at runtime to fix
>> 1810 up the entries based on the runtime load address of the kernel.
>> 1811
1854 # end of the "standard kernel features (exper 1812 # end of the "standard kernel features (expert users)" menu
1855 1813
1856 config ARCH_HAS_MEMBARRIER_CALLBACKS 1814 config ARCH_HAS_MEMBARRIER_CALLBACKS
1857 bool 1815 bool
1858 1816
1859 config ARCH_HAS_MEMBARRIER_SYNC_CORE 1817 config ARCH_HAS_MEMBARRIER_SYNC_CORE
1860 bool 1818 bool
1861 1819
1862 config HAVE_PERF_EVENTS 1820 config HAVE_PERF_EVENTS
1863 bool 1821 bool
1864 help 1822 help
1865 See tools/perf/design.txt for detai 1823 See tools/perf/design.txt for details.
1866 1824
1867 config GUEST_PERF_EVENTS 1825 config GUEST_PERF_EVENTS
1868 bool 1826 bool
1869 depends on HAVE_PERF_EVENTS 1827 depends on HAVE_PERF_EVENTS
1870 1828
1871 config PERF_USE_VMALLOC 1829 config PERF_USE_VMALLOC
1872 bool 1830 bool
1873 help 1831 help
1874 See tools/perf/design.txt for detai 1832 See tools/perf/design.txt for details
1875 1833
1876 menu "Kernel Performance Events And Counters" 1834 menu "Kernel Performance Events And Counters"
1877 1835
1878 config PERF_EVENTS 1836 config PERF_EVENTS
1879 bool "Kernel performance events and c 1837 bool "Kernel performance events and counters"
1880 default y if PROFILING 1838 default y if PROFILING
1881 depends on HAVE_PERF_EVENTS 1839 depends on HAVE_PERF_EVENTS
1882 select IRQ_WORK 1840 select IRQ_WORK
1883 help 1841 help
1884 Enable kernel support for various p 1842 Enable kernel support for various performance events provided
1885 by software and hardware. 1843 by software and hardware.
1886 1844
1887 Software events are supported eithe 1845 Software events are supported either built-in or via the
1888 use of generic tracepoints. 1846 use of generic tracepoints.
1889 1847
1890 Most modern CPUs support performanc 1848 Most modern CPUs support performance events via performance
1891 counter registers. These registers 1849 counter registers. These registers count the number of certain
1892 types of hw events: such as instruc 1850 types of hw events: such as instructions executed, cachemisses
1893 suffered, or branches mis-predicted 1851 suffered, or branches mis-predicted - without slowing down the
1894 kernel or applications. These regis 1852 kernel or applications. These registers can also trigger interrupts
1895 when a threshold number of events h 1853 when a threshold number of events have passed - and can thus be
1896 used to profile the code that runs 1854 used to profile the code that runs on that CPU.
1897 1855
1898 The Linux Performance Event subsyst 1856 The Linux Performance Event subsystem provides an abstraction of
1899 these software and hardware event c 1857 these software and hardware event capabilities, available via a
1900 system call and used by the "perf" 1858 system call and used by the "perf" utility in tools/perf/. It
1901 provides per task and per CPU count 1859 provides per task and per CPU counters, and it provides event
1902 capabilities on top of those. 1860 capabilities on top of those.
1903 1861
1904 Say Y if unsure. 1862 Say Y if unsure.
1905 1863
1906 config DEBUG_PERF_USE_VMALLOC 1864 config DEBUG_PERF_USE_VMALLOC
1907 default n 1865 default n
1908 bool "Debug: use vmalloc to back perf 1866 bool "Debug: use vmalloc to back perf mmap() buffers"
1909 depends on PERF_EVENTS && DEBUG_KERNE 1867 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
1910 select PERF_USE_VMALLOC 1868 select PERF_USE_VMALLOC
1911 help 1869 help
1912 Use vmalloc memory to back perf mma 1870 Use vmalloc memory to back perf mmap() buffers.
1913 1871
1914 Mostly useful for debugging the vma 1872 Mostly useful for debugging the vmalloc code on platforms
1915 that don't require it. 1873 that don't require it.
1916 1874
1917 Say N if unsure. 1875 Say N if unsure.
1918 1876
1919 endmenu 1877 endmenu
1920 1878
1921 config SYSTEM_DATA_VERIFICATION 1879 config SYSTEM_DATA_VERIFICATION
1922 def_bool n 1880 def_bool n
1923 select SYSTEM_TRUSTED_KEYRING 1881 select SYSTEM_TRUSTED_KEYRING
1924 select KEYS 1882 select KEYS
1925 select CRYPTO 1883 select CRYPTO
1926 select CRYPTO_RSA 1884 select CRYPTO_RSA
1927 select ASYMMETRIC_KEY_TYPE 1885 select ASYMMETRIC_KEY_TYPE
1928 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 1886 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1929 select ASN1 1887 select ASN1
1930 select OID_REGISTRY 1888 select OID_REGISTRY
1931 select X509_CERTIFICATE_PARSER 1889 select X509_CERTIFICATE_PARSER
1932 select PKCS7_MESSAGE_PARSER 1890 select PKCS7_MESSAGE_PARSER
1933 help 1891 help
1934 Provide PKCS#7 message verification 1892 Provide PKCS#7 message verification using the contents of the system
1935 trusted keyring to provide public k 1893 trusted keyring to provide public keys. This then can be used for
1936 module verification, kexec image ve 1894 module verification, kexec image verification and firmware blob
1937 verification. 1895 verification.
1938 1896
1939 config PROFILING 1897 config PROFILING
1940 bool "Profiling support" 1898 bool "Profiling support"
1941 help 1899 help
1942 Say Y here to enable the extended p 1900 Say Y here to enable the extended profiling support mechanisms used
1943 by profilers. 1901 by profilers.
1944 1902
1945 config RUST 1903 config RUST
1946 bool "Rust support" 1904 bool "Rust support"
1947 depends on HAVE_RUST 1905 depends on HAVE_RUST
1948 depends on RUST_IS_AVAILABLE 1906 depends on RUST_IS_AVAILABLE
>> 1907 depends on !CFI_CLANG
1949 depends on !MODVERSIONS 1908 depends on !MODVERSIONS
1950 depends on !GCC_PLUGIN_RANDSTRUCT !! 1909 depends on !GCC_PLUGINS
1951 depends on !RANDSTRUCT 1910 depends on !RANDSTRUCT
1952 depends on !DEBUG_INFO_BTF || PAHOLE_ 1911 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 1912 help
1959 Enables Rust support in the kernel. 1913 Enables Rust support in the kernel.
1960 1914
1961 This allows other Rust-related opti 1915 This allows other Rust-related options, like drivers written in Rust,
1962 to be selected. 1916 to be selected.
1963 1917
1964 It is also required to be able to l 1918 It is also required to be able to load external kernel modules
1965 written in Rust. 1919 written in Rust.
1966 1920
1967 See Documentation/rust/ for more in 1921 See Documentation/rust/ for more information.
1968 1922
1969 If unsure, say N. 1923 If unsure, say N.
1970 1924
1971 config RUSTC_VERSION_TEXT 1925 config RUSTC_VERSION_TEXT
1972 string 1926 string
1973 depends on RUST 1927 depends on RUST
1974 default "$(RUSTC_VERSION_TEXT)" !! 1928 default $(shell,command -v $(RUSTC) >/dev/null 2>&1 && $(RUSTC) --version || echo n)
1975 help <<
1976 See `CC_VERSION_TEXT`. <<
1977 1929
1978 config BINDGEN_VERSION_TEXT 1930 config BINDGEN_VERSION_TEXT
1979 string 1931 string
1980 depends on RUST 1932 depends on RUST
1981 # The dummy parameter `workaround-for !! 1933 default $(shell,command -v $(BINDGEN) >/dev/null 2>&1 && $(BINDGEN) --version || echo n)
1982 # (https://github.com/rust-lang/rust- <<
1983 # the minimum version is upgraded pas <<
1984 default "$(shell,$(BINDGEN) --version <<
1985 1934
1986 # 1935 #
1987 # Place an empty function call at each tracep 1936 # Place an empty function call at each tracepoint site. Can be
1988 # dynamically changed for a probe function. 1937 # dynamically changed for a probe function.
1989 # 1938 #
1990 config TRACEPOINTS 1939 config TRACEPOINTS
1991 bool 1940 bool
1992 1941
1993 source "kernel/Kconfig.kexec" 1942 source "kernel/Kconfig.kexec"
1994 1943
1995 endmenu # General setup 1944 endmenu # General setup
1996 1945
1997 source "arch/Kconfig" 1946 source "arch/Kconfig"
1998 1947
1999 config RT_MUTEXES 1948 config RT_MUTEXES
2000 bool 1949 bool
2001 default y if PREEMPT_RT 1950 default y if PREEMPT_RT
2002 1951
>> 1952 config BASE_SMALL
>> 1953 int
>> 1954 default 0 if BASE_FULL
>> 1955 default 1 if !BASE_FULL
>> 1956
2003 config MODULE_SIG_FORMAT 1957 config MODULE_SIG_FORMAT
2004 def_bool n 1958 def_bool n
2005 select SYSTEM_DATA_VERIFICATION 1959 select SYSTEM_DATA_VERIFICATION
2006 1960
2007 source "kernel/module/Kconfig" 1961 source "kernel/module/Kconfig"
2008 1962
2009 config INIT_ALL_POSSIBLE 1963 config INIT_ALL_POSSIBLE
2010 bool 1964 bool
2011 help 1965 help
2012 Back when each arch used to define 1966 Back when each arch used to define their own cpu_online_mask and
2013 cpu_possible_mask, some of them cho 1967 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
2014 with all 1s, and others with all 0s 1968 with all 1s, and others with all 0s. When they were centralised,
2015 it was better to provide this optio 1969 it was better to provide this option than to break all the archs
2016 and have several arch maintainers p 1970 and have several arch maintainers pursuing me down dark alleys.
2017 1971
2018 source "block/Kconfig" 1972 source "block/Kconfig"
2019 1973
2020 config PREEMPT_NOTIFIERS 1974 config PREEMPT_NOTIFIERS
2021 bool 1975 bool
2022 1976
2023 config PADATA 1977 config PADATA
2024 depends on SMP 1978 depends on SMP
2025 bool 1979 bool
2026 1980
2027 config ASN1 1981 config ASN1
2028 tristate 1982 tristate
2029 help 1983 help
2030 Build a simple ASN.1 grammar compil 1984 Build a simple ASN.1 grammar compiler that produces a bytecode output
2031 that can be interpreted by the ASN. 1985 that can be interpreted by the ASN.1 stream decoder and used to
2032 inform it as to what tags are to be 1986 inform it as to what tags are to be expected in a stream and what
2033 functions to call on what tags. 1987 functions to call on what tags.
2034 1988
2035 source "kernel/Kconfig.locks" 1989 source "kernel/Kconfig.locks"
2036 1990
2037 config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 1991 config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
2038 bool <<
2039 <<
2040 config ARCH_HAS_PREPARE_SYNC_CORE_CMD <<
2041 bool 1992 bool
2042 1993
2043 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 1994 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
2044 bool 1995 bool
2045 1996
2046 # It may be useful for an architecture to ove 1997 # It may be useful for an architecture to override the definitions of the
2047 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() ma 1998 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h>
2048 # and the COMPAT_ variants in <linux/compat.h 1999 # and the COMPAT_ variants in <linux/compat.h>, in particular to use a
2049 # different calling convention for syscalls. 2000 # different calling convention for syscalls. They can also override the
2050 # macros for not-implemented syscalls in kern 2001 # macros for not-implemented syscalls in kernel/sys_ni.c and
2051 # kernel/time/posix-stubs.c. All these overri 2002 # kernel/time/posix-stubs.c. All these overrides need to be available in
2052 # <asm/syscall_wrapper.h>. 2003 # <asm/syscall_wrapper.h>.
2053 config ARCH_HAS_SYSCALL_WRAPPER 2004 config ARCH_HAS_SYSCALL_WRAPPER
2054 def_bool n 2005 def_bool n
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