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 <<
71 def_bool $(success,$(srctree)/scripts/ <<
72 help <<
73 This shows whether a suitable Rust t <<
74 <<
75 Please see Documentation/rust/quick- <<
76 to satisfy the build requirements of <<
77 <<
78 In particular, the Makefile target ' <<
79 why the Rust toolchain is not being <<
80 <<
81 config RUSTC_LLVM_VERSION <<
82 int <<
83 default $(rustc-llvm-version) <<
84 <<
85 config CC_CAN_LINK 63 config CC_CAN_LINK
86 bool 64 bool
87 default $(success,$(srctree)/scripts/c 65 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag)) if 64BIT
88 default $(success,$(srctree)/scripts/c 66 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m32-flag))
89 67
90 config CC_CAN_LINK_STATIC 68 config CC_CAN_LINK_STATIC
91 bool 69 bool
92 default $(success,$(srctree)/scripts/c 70 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag) -static) if 64BIT
93 default $(success,$(srctree)/scripts/c 71 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m32-flag) -static)
94 72
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 73 config CC_HAS_ASM_GOTO_OUTPUT
105 def_bool y !! 74 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 75
109 config CC_HAS_ASM_GOTO_TIED_OUTPUT 76 config CC_HAS_ASM_GOTO_TIED_OUTPUT
110 depends on CC_HAS_ASM_GOTO_OUTPUT 77 depends on CC_HAS_ASM_GOTO_OUTPUT
111 # Detect buggy gcc and clang, fixed in 78 # Detect buggy gcc and clang, fixed in gcc-11 clang-14.
112 def_bool $(success,echo 'int foo(int * 79 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 80
114 config TOOLS_SUPPORT_RELR 81 config TOOLS_SUPPORT_RELR
115 def_bool $(success,env "CC=$(CC)" "LD= 82 def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh)
116 83
117 config CC_HAS_ASM_INLINE 84 config CC_HAS_ASM_INLINE
118 def_bool $(success,echo 'void foo(void 85 def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null)
119 86
120 config CC_HAS_NO_PROFILE_FN_ATTR 87 config CC_HAS_NO_PROFILE_FN_ATTR
121 def_bool $(success,echo '__attribute__ 88 def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror)
122 89
123 config PAHOLE_VERSION 90 config PAHOLE_VERSION
124 int 91 int
125 default $(shell,$(srctree)/scripts/pah 92 default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE))
126 93
127 config CONSTRUCTORS 94 config CONSTRUCTORS
128 bool 95 bool
129 96
130 config IRQ_WORK 97 config IRQ_WORK
131 def_bool y if SMP !! 98 bool
132 99
133 config BUILDTIME_TABLE_SORT 100 config BUILDTIME_TABLE_SORT
134 bool 101 bool
135 102
136 config THREAD_INFO_IN_TASK 103 config THREAD_INFO_IN_TASK
137 bool 104 bool
138 help 105 help
139 Select this to move thread_info off 106 Select this to move thread_info off the stack into task_struct. To
140 make this work, an arch will need to 107 make this work, an arch will need to remove all thread_info fields
141 except flags and fix any runtime bug 108 except flags and fix any runtime bugs.
142 109
143 One subtle change that will be neede 110 One subtle change that will be needed is to use try_get_task_stack()
144 and put_task_stack() in save_thread_ 111 and put_task_stack() in save_thread_stack_tsk() and get_wchan().
145 112
146 menu "General setup" 113 menu "General setup"
147 114
148 config BROKEN 115 config BROKEN
149 bool 116 bool
150 117
151 config BROKEN_ON_SMP 118 config BROKEN_ON_SMP
152 bool 119 bool
153 depends on BROKEN || !SMP 120 depends on BROKEN || !SMP
154 default y 121 default y
155 122
156 config INIT_ENV_ARG_LIMIT 123 config INIT_ENV_ARG_LIMIT
157 int 124 int
158 default 32 if !UML 125 default 32 if !UML
159 default 128 if UML 126 default 128 if UML
160 help 127 help
161 Maximum of each of the number of arg 128 Maximum of each of the number of arguments and environment
162 variables passed to init from the ke 129 variables passed to init from the kernel command line.
163 130
164 config COMPILE_TEST 131 config COMPILE_TEST
165 bool "Compile also drivers which will 132 bool "Compile also drivers which will not load"
166 depends on HAS_IOMEM 133 depends on HAS_IOMEM
167 help 134 help
168 Some drivers can be compiled on a di 135 Some drivers can be compiled on a different platform than they are
169 intended to be run on. Despite they 136 intended to be run on. Despite they cannot be loaded there (or even
170 when they load they cannot be used d 137 when they load they cannot be used due to missing HW support),
171 developers still, opposing to distri 138 developers still, opposing to distributors, might want to build such
172 drivers to compile-test them. 139 drivers to compile-test them.
173 140
174 If you are a developer and want to b 141 If you are a developer and want to build everything available, say Y
175 here. If you are a user/distributor, 142 here. If you are a user/distributor, say N here to exclude useless
176 drivers to be distributed. 143 drivers to be distributed.
177 144
178 config WERROR 145 config WERROR
179 bool "Compile the kernel with warnings 146 bool "Compile the kernel with warnings as errors"
180 default COMPILE_TEST 147 default COMPILE_TEST
181 help 148 help
182 A kernel build should not cause any 149 A kernel build should not cause any compiler warnings, and this
183 enables the '-Werror' (for C) and '- !! 150 enables the '-Werror' flag to enforce that rule by default.
184 to enforce that rule by default. Cer <<
185 such as the linker may be upgraded t <<
186 well. <<
187 151
188 However, if you have a new (or very !! 152 However, if you have a new (or very old) compiler with odd and
189 and unusual warnings, or you have so !! 153 unusual warnings, or you have some architecture with problems,
190 you may need to disable this config 154 you may need to disable this config option in order to
191 successfully build the kernel. 155 successfully build the kernel.
192 156
193 If in doubt, say Y. 157 If in doubt, say Y.
194 158
195 config UAPI_HEADER_TEST 159 config UAPI_HEADER_TEST
196 bool "Compile test UAPI headers" 160 bool "Compile test UAPI headers"
197 depends on HEADERS_INSTALL && CC_CAN_L 161 depends on HEADERS_INSTALL && CC_CAN_LINK
198 help 162 help
199 Compile test headers exported to use 163 Compile test headers exported to user-space to ensure they are
200 self-contained, i.e. compilable as s 164 self-contained, i.e. compilable as standalone units.
201 165
202 If you are a developer or tester and 166 If you are a developer or tester and want to ensure the exported
203 headers are self-contained, say Y he 167 headers are self-contained, say Y here. Otherwise, choose N.
204 168
205 config LOCALVERSION 169 config LOCALVERSION
206 string "Local version - append to kern 170 string "Local version - append to kernel release"
207 help 171 help
208 Append an extra string to the end of 172 Append an extra string to the end of your kernel version.
209 This will show up when you type unam 173 This will show up when you type uname, for example.
210 The string you set here will be appe 174 The string you set here will be appended after the contents of
211 any files with a filename matching l 175 any files with a filename matching localversion* in your
212 object and source tree, in that orde 176 object and source tree, in that order. Your total string can
213 be a maximum of 64 characters. 177 be a maximum of 64 characters.
214 178
215 config LOCALVERSION_AUTO 179 config LOCALVERSION_AUTO
216 bool "Automatically append version inf 180 bool "Automatically append version information to the version string"
217 default y 181 default y
218 depends on !COMPILE_TEST 182 depends on !COMPILE_TEST
219 help 183 help
220 This will try to automatically deter 184 This will try to automatically determine if the current tree is a
221 release tree by looking for git tags 185 release tree by looking for git tags that belong to the current
222 top of tree revision. 186 top of tree revision.
223 187
224 A string of the format -gxxxxxxxx wi 188 A string of the format -gxxxxxxxx will be added to the localversion
225 if a git-based tree is found. The s 189 if a git-based tree is found. The string generated by this will be
226 appended after any matching localver 190 appended after any matching localversion* files, and after the value
227 set in CONFIG_LOCALVERSION. 191 set in CONFIG_LOCALVERSION.
228 192
229 (The actual string used here is the !! 193 (The actual string used here is the first eight characters produced
230 by running the command: 194 by running the command:
231 195
232 $ git rev-parse --verify HEAD 196 $ git rev-parse --verify HEAD
233 197
234 which is done within the script "scr 198 which is done within the script "scripts/setlocalversion".)
235 199
236 config BUILD_SALT 200 config BUILD_SALT
237 string "Build ID Salt" 201 string "Build ID Salt"
238 default "" 202 default ""
239 help 203 help
240 The build ID is used to link binarie 204 The build ID is used to link binaries and their debug info. Setting
241 this option will use the value in th 205 this option will use the value in the calculation of the build id.
242 This is mostly useful for distributi 206 This is mostly useful for distributions which want to ensure the
243 build is unique between builds. It's 207 build is unique between builds. It's safe to leave the default.
244 208
245 config HAVE_KERNEL_GZIP 209 config HAVE_KERNEL_GZIP
246 bool 210 bool
247 211
248 config HAVE_KERNEL_BZIP2 212 config HAVE_KERNEL_BZIP2
249 bool 213 bool
250 214
251 config HAVE_KERNEL_LZMA 215 config HAVE_KERNEL_LZMA
252 bool 216 bool
253 217
254 config HAVE_KERNEL_XZ 218 config HAVE_KERNEL_XZ
255 bool 219 bool
256 220
257 config HAVE_KERNEL_LZO 221 config HAVE_KERNEL_LZO
258 bool 222 bool
259 223
260 config HAVE_KERNEL_LZ4 224 config HAVE_KERNEL_LZ4
261 bool 225 bool
262 226
263 config HAVE_KERNEL_ZSTD 227 config HAVE_KERNEL_ZSTD
264 bool 228 bool
265 229
266 config HAVE_KERNEL_UNCOMPRESSED 230 config HAVE_KERNEL_UNCOMPRESSED
267 bool 231 bool
268 232
269 choice 233 choice
270 prompt "Kernel compression mode" 234 prompt "Kernel compression mode"
271 default KERNEL_GZIP 235 default KERNEL_GZIP
272 depends on HAVE_KERNEL_GZIP || HAVE_KE 236 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 237 help
274 The linux kernel is a kind of self-e 238 The linux kernel is a kind of self-extracting executable.
275 Several compression algorithms are a 239 Several compression algorithms are available, which differ
276 in efficiency, compression and decom 240 in efficiency, compression and decompression speed.
277 Compression speed is only relevant w 241 Compression speed is only relevant when building a kernel.
278 Decompression speed is relevant at e 242 Decompression speed is relevant at each boot.
279 243
280 If you have any problems with bzip2 244 If you have any problems with bzip2 or lzma compressed
281 kernels, mail me (Alain Knaff) <alain 245 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
282 version of this functionality (bzip2 246 version of this functionality (bzip2 only), for 2.4, was
283 supplied by Christian Ludwig) 247 supplied by Christian Ludwig)
284 248
285 High compression options are mostly 249 High compression options are mostly useful for users, who
286 are low on disk space (embedded syst 250 are low on disk space (embedded systems), but for whom ram
287 size matters less. 251 size matters less.
288 252
289 If in doubt, select 'gzip' 253 If in doubt, select 'gzip'
290 254
291 config KERNEL_GZIP 255 config KERNEL_GZIP
292 bool "Gzip" 256 bool "Gzip"
293 depends on HAVE_KERNEL_GZIP 257 depends on HAVE_KERNEL_GZIP
294 help 258 help
295 The old and tried gzip compression. 259 The old and tried gzip compression. It provides a good balance
296 between compression ratio and decomp 260 between compression ratio and decompression speed.
297 261
298 config KERNEL_BZIP2 262 config KERNEL_BZIP2
299 bool "Bzip2" 263 bool "Bzip2"
300 depends on HAVE_KERNEL_BZIP2 264 depends on HAVE_KERNEL_BZIP2
301 help 265 help
302 Its compression ratio and speed is i 266 Its compression ratio and speed is intermediate.
303 Decompression speed is slowest among 267 Decompression speed is slowest among the choices. The kernel
304 size is about 10% smaller with bzip2 268 size is about 10% smaller with bzip2, in comparison to gzip.
305 Bzip2 uses a large amount of memory. 269 Bzip2 uses a large amount of memory. For modern kernels you
306 will need at least 8MB RAM or more f 270 will need at least 8MB RAM or more for booting.
307 271
308 config KERNEL_LZMA 272 config KERNEL_LZMA
309 bool "LZMA" 273 bool "LZMA"
310 depends on HAVE_KERNEL_LZMA 274 depends on HAVE_KERNEL_LZMA
311 help 275 help
312 This compression algorithm's ratio i 276 This compression algorithm's ratio is best. Decompression speed
313 is between gzip and bzip2. Compress 277 is between gzip and bzip2. Compression is slowest.
314 The kernel size is about 33% smaller 278 The kernel size is about 33% smaller with LZMA in comparison to gzip.
315 279
316 config KERNEL_XZ 280 config KERNEL_XZ
317 bool "XZ" 281 bool "XZ"
318 depends on HAVE_KERNEL_XZ 282 depends on HAVE_KERNEL_XZ
319 help 283 help
320 XZ uses the LZMA2 algorithm and inst 284 XZ uses the LZMA2 algorithm and instruction set specific
321 BCJ filters which can improve compre 285 BCJ filters which can improve compression ratio of executable
322 code. The size of the kernel is abou 286 code. The size of the kernel is about 30% smaller with XZ in
323 comparison to gzip. On architectures 287 comparison to gzip. On architectures for which there is a BCJ
324 filter (i386, x86_64, ARM, ARM64, RI !! 288 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
325 and SPARC), XZ will create a few per !! 289 will create a few percent smaller kernel than plain LZMA.
326 plain LZMA. <<
327 290
328 The speed is about the same as with 291 The speed is about the same as with LZMA: The decompression
329 speed of XZ is better than that of b 292 speed of XZ is better than that of bzip2 but worse than gzip
330 and LZO. Compression is slow. 293 and LZO. Compression is slow.
331 294
332 config KERNEL_LZO 295 config KERNEL_LZO
333 bool "LZO" 296 bool "LZO"
334 depends on HAVE_KERNEL_LZO 297 depends on HAVE_KERNEL_LZO
335 help 298 help
336 Its compression ratio is the poorest 299 Its compression ratio is the poorest among the choices. The kernel
337 size is about 10% bigger than gzip; 300 size is about 10% bigger than gzip; however its speed
338 (both compression and decompression) 301 (both compression and decompression) is the fastest.
339 302
340 config KERNEL_LZ4 303 config KERNEL_LZ4
341 bool "LZ4" 304 bool "LZ4"
342 depends on HAVE_KERNEL_LZ4 305 depends on HAVE_KERNEL_LZ4
343 help 306 help
344 LZ4 is an LZ77-type compressor with 307 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
345 A preliminary version of LZ4 de/comp 308 A preliminary version of LZ4 de/compression tool is available at
346 <https://code.google.com/p/lz4/>. 309 <https://code.google.com/p/lz4/>.
347 310
348 Its compression ratio is worse than 311 Its compression ratio is worse than LZO. The size of the kernel
349 is about 8% bigger than LZO. But the 312 is about 8% bigger than LZO. But the decompression speed is
350 faster than LZO. 313 faster than LZO.
351 314
352 config KERNEL_ZSTD 315 config KERNEL_ZSTD
353 bool "ZSTD" 316 bool "ZSTD"
354 depends on HAVE_KERNEL_ZSTD 317 depends on HAVE_KERNEL_ZSTD
355 help 318 help
356 ZSTD is a compression algorithm targ 319 ZSTD is a compression algorithm targeting intermediate compression
357 with fast decompression speed. It wi 320 with fast decompression speed. It will compress better than GZIP and
358 decompress around the same speed as 321 decompress around the same speed as LZO, but slower than LZ4. You
359 will need at least 192 KB RAM or mor 322 will need at least 192 KB RAM or more for booting. The zstd command
360 line tool is required for compressio 323 line tool is required for compression.
361 324
362 config KERNEL_UNCOMPRESSED 325 config KERNEL_UNCOMPRESSED
363 bool "None" 326 bool "None"
364 depends on HAVE_KERNEL_UNCOMPRESSED 327 depends on HAVE_KERNEL_UNCOMPRESSED
365 help 328 help
366 Produce uncompressed kernel image. T 329 Produce uncompressed kernel image. This option is usually not what
367 you want. It is useful for debugging 330 you want. It is useful for debugging the kernel in slow simulation
368 environments, where decompressing an 331 environments, where decompressing and moving the kernel is awfully
369 slow. This option allows early boot 332 slow. This option allows early boot code to skip the decompressor
370 and jump right at uncompressed kerne 333 and jump right at uncompressed kernel image.
371 334
372 endchoice 335 endchoice
373 336
374 config DEFAULT_INIT 337 config DEFAULT_INIT
375 string "Default init path" 338 string "Default init path"
376 default "" 339 default ""
377 help 340 help
378 This option determines the default i 341 This option determines the default init for the system if no init=
379 option is passed on the kernel comma 342 option is passed on the kernel command line. If the requested path is
380 not present, we will still then move 343 not present, we will still then move on to attempting further
381 locations (e.g. /sbin/init, etc). If 344 locations (e.g. /sbin/init, etc). If this is empty, we will just use
382 the fallback list when init= is not 345 the fallback list when init= is not passed.
383 346
384 config DEFAULT_HOSTNAME 347 config DEFAULT_HOSTNAME
385 string "Default hostname" 348 string "Default hostname"
386 default "(none)" 349 default "(none)"
387 help 350 help
388 This option determines the default s 351 This option determines the default system hostname before userspace
389 calls sethostname(2). The kernel tra 352 calls sethostname(2). The kernel traditionally uses "(none)" here,
390 but you may wish to use a different 353 but you may wish to use a different default here to make a minimal
391 system more usable with less configu 354 system more usable with less configuration.
392 355
393 config SYSVIPC 356 config SYSVIPC
394 bool "System V IPC" 357 bool "System V IPC"
395 help 358 help
396 Inter Process Communication is a sui 359 Inter Process Communication is a suite of library functions and
397 system calls which let processes (ru 360 system calls which let processes (running programs) synchronize and
398 exchange information. It is generall 361 exchange information. It is generally considered to be a good thing,
399 and some programs won't run unless y 362 and some programs won't run unless you say Y here. In particular, if
400 you want to run the DOS emulator dos 363 you want to run the DOS emulator dosemu under Linux (read the
401 DOSEMU-HOWTO, available from <http:/ 364 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
402 you'll need to say Y here. 365 you'll need to say Y here.
403 366
404 You can find documentation about IPC 367 You can find documentation about IPC with "info ipc" and also in
405 section 6.4 of the Linux Programmer' 368 section 6.4 of the Linux Programmer's Guide, available from
406 <http://www.tldp.org/guides.html>. 369 <http://www.tldp.org/guides.html>.
407 370
408 config SYSVIPC_SYSCTL 371 config SYSVIPC_SYSCTL
409 bool 372 bool
410 depends on SYSVIPC 373 depends on SYSVIPC
411 depends on SYSCTL 374 depends on SYSCTL
412 default y 375 default y
413 376
414 config SYSVIPC_COMPAT 377 config SYSVIPC_COMPAT
415 def_bool y 378 def_bool y
416 depends on COMPAT && SYSVIPC 379 depends on COMPAT && SYSVIPC
417 380
418 config POSIX_MQUEUE 381 config POSIX_MQUEUE
419 bool "POSIX Message Queues" 382 bool "POSIX Message Queues"
420 depends on NET 383 depends on NET
421 help 384 help
422 POSIX variant of message queues is a 385 POSIX variant of message queues is a part of IPC. In POSIX message
423 queues every message has a priority 386 queues every message has a priority which decides about succession
424 of receiving it by a process. If you 387 of receiving it by a process. If you want to compile and run
425 programs written e.g. for Solaris wi 388 programs written e.g. for Solaris with use of its POSIX message
426 queues (functions mq_*) say Y here. 389 queues (functions mq_*) say Y here.
427 390
428 POSIX message queues are visible as 391 POSIX message queues are visible as a filesystem called 'mqueue'
429 and can be mounted somewhere if you 392 and can be mounted somewhere if you want to do filesystem
430 operations on message queues. 393 operations on message queues.
431 394
432 If unsure, say Y. 395 If unsure, say Y.
433 396
434 config POSIX_MQUEUE_SYSCTL 397 config POSIX_MQUEUE_SYSCTL
435 bool 398 bool
436 depends on POSIX_MQUEUE 399 depends on POSIX_MQUEUE
437 depends on SYSCTL 400 depends on SYSCTL
438 default y 401 default y
439 402
440 config WATCH_QUEUE 403 config WATCH_QUEUE
441 bool "General notification queue" 404 bool "General notification queue"
442 default n 405 default n
443 help 406 help
444 407
445 This is a general notification queue 408 This is a general notification queue for the kernel to pass events to
446 userspace by splicing them into pipe 409 userspace by splicing them into pipes. It can be used in conjunction
447 with watches for key/keyring change 410 with watches for key/keyring change notifications and device
448 notifications. 411 notifications.
449 412
450 See Documentation/core-api/watch_que 413 See Documentation/core-api/watch_queue.rst
451 414
452 config CROSS_MEMORY_ATTACH 415 config CROSS_MEMORY_ATTACH
453 bool "Enable process_vm_readv/writev s 416 bool "Enable process_vm_readv/writev syscalls"
454 depends on MMU 417 depends on MMU
455 default y 418 default y
456 help 419 help
457 Enabling this option adds the system 420 Enabling this option adds the system calls process_vm_readv and
458 process_vm_writev which allow a proc 421 process_vm_writev which allow a process with the correct privileges
459 to directly read from or write to an 422 to directly read from or write to another process' address space.
460 See the man page for more details. 423 See the man page for more details.
461 424
462 config USELIB 425 config USELIB
463 bool "uselib syscall (for libc5 and ea 426 bool "uselib syscall (for libc5 and earlier)"
464 default ALPHA || M68K || SPARC 427 default ALPHA || M68K || SPARC
465 help 428 help
466 This option enables the uselib sysca 429 This option enables the uselib syscall, a system call used in the
467 dynamic linker from libc5 and earlie 430 dynamic linker from libc5 and earlier. glibc does not use this
468 system call. If you intend to run p 431 system call. If you intend to run programs built on libc5 or
469 earlier, you may need to enable this 432 earlier, you may need to enable this syscall. Current systems
470 running glibc can safely disable thi 433 running glibc can safely disable this.
471 434
472 config AUDIT 435 config AUDIT
473 bool "Auditing support" 436 bool "Auditing support"
474 depends on NET 437 depends on NET
475 help 438 help
476 Enable auditing infrastructure that 439 Enable auditing infrastructure that can be used with another
477 kernel subsystem, such as SELinux (w 440 kernel subsystem, such as SELinux (which requires this for
478 logging of avc messages output). Sy 441 logging of avc messages output). System call auditing is included
479 on architectures which support it. 442 on architectures which support it.
480 443
481 config HAVE_ARCH_AUDITSYSCALL 444 config HAVE_ARCH_AUDITSYSCALL
482 bool 445 bool
483 446
484 config AUDITSYSCALL 447 config AUDITSYSCALL
485 def_bool y 448 def_bool y
486 depends on AUDIT && HAVE_ARCH_AUDITSYS 449 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
487 select FSNOTIFY 450 select FSNOTIFY
488 451
489 source "kernel/irq/Kconfig" 452 source "kernel/irq/Kconfig"
490 source "kernel/time/Kconfig" 453 source "kernel/time/Kconfig"
491 source "kernel/bpf/Kconfig" 454 source "kernel/bpf/Kconfig"
492 source "kernel/Kconfig.preempt" 455 source "kernel/Kconfig.preempt"
493 456
494 menu "CPU/Task time and stats accounting" 457 menu "CPU/Task time and stats accounting"
495 458
496 config VIRT_CPU_ACCOUNTING 459 config VIRT_CPU_ACCOUNTING
497 bool 460 bool
498 461
499 choice 462 choice
500 prompt "Cputime accounting" 463 prompt "Cputime accounting"
501 default TICK_CPU_ACCOUNTING !! 464 default TICK_CPU_ACCOUNTING if !PPC64
>> 465 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
502 466
503 # Kind of a stub config for the pure tick base 467 # Kind of a stub config for the pure tick based cputime accounting
504 config TICK_CPU_ACCOUNTING 468 config TICK_CPU_ACCOUNTING
505 bool "Simple tick based cputime accoun 469 bool "Simple tick based cputime accounting"
506 depends on !S390 && !NO_HZ_FULL 470 depends on !S390 && !NO_HZ_FULL
507 help 471 help
508 This is the basic tick based cputime 472 This is the basic tick based cputime accounting that maintains
509 statistics about user, system and id 473 statistics about user, system and idle time spent on per jiffies
510 granularity. 474 granularity.
511 475
512 If unsure, say Y. 476 If unsure, say Y.
513 477
514 config VIRT_CPU_ACCOUNTING_NATIVE 478 config VIRT_CPU_ACCOUNTING_NATIVE
515 bool "Deterministic task and CPU time 479 bool "Deterministic task and CPU time accounting"
516 depends on HAVE_VIRT_CPU_ACCOUNTING && 480 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
517 select VIRT_CPU_ACCOUNTING 481 select VIRT_CPU_ACCOUNTING
518 help 482 help
519 Select this option to enable more ac 483 Select this option to enable more accurate task and CPU time
520 accounting. This is done by reading 484 accounting. This is done by reading a CPU counter on each
521 kernel entry and exit and on transit 485 kernel entry and exit and on transitions within the kernel
522 between system, softirq and hardirq 486 between system, softirq and hardirq state, so there is a
523 small performance impact. In the ca 487 small performance impact. In the case of s390 or IBM POWER > 5,
524 this also enables accounting of stol 488 this also enables accounting of stolen time on logically-partitioned
525 systems. 489 systems.
526 490
527 config VIRT_CPU_ACCOUNTING_GEN 491 config VIRT_CPU_ACCOUNTING_GEN
528 bool "Full dynticks CPU time accountin 492 bool "Full dynticks CPU time accounting"
529 depends on HAVE_CONTEXT_TRACKING_USER 493 depends on HAVE_CONTEXT_TRACKING_USER
530 depends on HAVE_VIRT_CPU_ACCOUNTING_GE 494 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
531 depends on GENERIC_CLOCKEVENTS 495 depends on GENERIC_CLOCKEVENTS
532 select VIRT_CPU_ACCOUNTING 496 select VIRT_CPU_ACCOUNTING
533 select CONTEXT_TRACKING_USER 497 select CONTEXT_TRACKING_USER
534 help 498 help
535 Select this option to enable task an 499 Select this option to enable task and CPU time accounting on full
536 dynticks systems. This accounting is 500 dynticks systems. This accounting is implemented by watching every
537 kernel-user boundaries using the con 501 kernel-user boundaries using the context tracking subsystem.
538 The accounting is thus performed at 502 The accounting is thus performed at the expense of some significant
539 overhead. 503 overhead.
540 504
541 For now this is only useful if you a 505 For now this is only useful if you are working on the full
542 dynticks subsystem development. 506 dynticks subsystem development.
543 507
544 If unsure, say N. 508 If unsure, say N.
545 509
546 endchoice 510 endchoice
547 511
548 config IRQ_TIME_ACCOUNTING 512 config IRQ_TIME_ACCOUNTING
549 bool "Fine granularity task level IRQ 513 bool "Fine granularity task level IRQ time accounting"
550 depends on HAVE_IRQ_TIME_ACCOUNTING && 514 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
551 help 515 help
552 Select this option to enable fine gr 516 Select this option to enable fine granularity task irq time
553 accounting. This is done by reading 517 accounting. This is done by reading a timestamp on each
554 transitions between softirq and hard 518 transitions between softirq and hardirq state, so there can be a
555 small performance impact. 519 small performance impact.
556 520
557 If in doubt, say N here. 521 If in doubt, say N here.
558 522
559 config HAVE_SCHED_AVG_IRQ 523 config HAVE_SCHED_AVG_IRQ
560 def_bool y 524 def_bool y
561 depends on IRQ_TIME_ACCOUNTING || PARA 525 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING
562 depends on SMP 526 depends on SMP
563 527
564 config SCHED_HW_PRESSURE !! 528 config SCHED_THERMAL_PRESSURE
565 bool 529 bool
566 default y if ARM && ARM_CPU_TOPOLOGY 530 default y if ARM && ARM_CPU_TOPOLOGY
567 default y if ARM64 531 default y if ARM64
568 depends on SMP 532 depends on SMP
569 depends on CPU_FREQ_THERMAL 533 depends on CPU_FREQ_THERMAL
570 help 534 help
571 Select this option to enable HW pres !! 535 Select this option to enable thermal pressure accounting in the
572 scheduler. HW pressure is the value !! 536 scheduler. Thermal pressure is the value conveyed to the scheduler
573 that reflects the reduction in CPU c 537 that reflects the reduction in CPU compute capacity resulted from
574 HW throttling. HW throttling occurs !! 538 thermal throttling. Thermal throttling occurs when the performance of
575 a CPU is capped due to high operatin !! 539 a CPU is capped due to high operating temperatures.
576 540
577 If selected, the scheduler will be a 541 If selected, the scheduler will be able to balance tasks accordingly,
578 i.e. put less load on throttled CPUs 542 i.e. put less load on throttled CPUs than on non/less throttled ones.
579 543
580 This requires the architecture to im 544 This requires the architecture to implement
581 arch_update_hw_pressure() and arch_s !! 545 arch_update_thermal_pressure() and arch_scale_thermal_pressure().
582 546
583 config BSD_PROCESS_ACCT 547 config BSD_PROCESS_ACCT
584 bool "BSD Process Accounting" 548 bool "BSD Process Accounting"
585 depends on MULTIUSER 549 depends on MULTIUSER
586 help 550 help
587 If you say Y here, a user level prog 551 If you say Y here, a user level program will be able to instruct the
588 kernel (via a special system call) t 552 kernel (via a special system call) to write process accounting
589 information to a file: whenever a pr 553 information to a file: whenever a process exits, information about
590 that process will be appended to the 554 that process will be appended to the file by the kernel. The
591 information includes things such as 555 information includes things such as creation time, owning user,
592 command name, memory usage, controll 556 command name, memory usage, controlling terminal etc. (the complete
593 list is in the struct acct in <file: 557 list is in the struct acct in <file:include/linux/acct.h>). It is
594 up to the user level program to do u 558 up to the user level program to do useful things with this
595 information. This is generally a go 559 information. This is generally a good idea, so say Y.
596 560
597 config BSD_PROCESS_ACCT_V3 561 config BSD_PROCESS_ACCT_V3
598 bool "BSD Process Accounting version 3 562 bool "BSD Process Accounting version 3 file format"
599 depends on BSD_PROCESS_ACCT 563 depends on BSD_PROCESS_ACCT
600 default n 564 default n
601 help 565 help
602 If you say Y here, the process accou 566 If you say Y here, the process accounting information is written
603 in a new file format that also logs 567 in a new file format that also logs the process IDs of each
604 process and its parent. Note that th 568 process and its parent. Note that this file format is incompatible
605 with previous v0/v1/v2 file formats, 569 with previous v0/v1/v2 file formats, so you will need updated tools
606 for processing it. A preliminary ver 570 for processing it. A preliminary version of these tools is available
607 at <http://www.gnu.org/software/acct 571 at <http://www.gnu.org/software/acct/>.
608 572
609 config TASKSTATS 573 config TASKSTATS
610 bool "Export task/process statistics t 574 bool "Export task/process statistics through netlink"
611 depends on NET 575 depends on NET
612 depends on MULTIUSER 576 depends on MULTIUSER
613 default n 577 default n
614 help 578 help
615 Export selected statistics for tasks 579 Export selected statistics for tasks/processes through the
616 generic netlink interface. Unlike BS 580 generic netlink interface. Unlike BSD process accounting, the
617 statistics are available during the 581 statistics are available during the lifetime of tasks/processes as
618 responses to commands. Like BSD acco 582 responses to commands. Like BSD accounting, they are sent to user
619 space on task exit. 583 space on task exit.
620 584
621 Say N if unsure. 585 Say N if unsure.
622 586
623 config TASK_DELAY_ACCT 587 config TASK_DELAY_ACCT
624 bool "Enable per-task delay accounting 588 bool "Enable per-task delay accounting"
625 depends on TASKSTATS 589 depends on TASKSTATS
626 select SCHED_INFO 590 select SCHED_INFO
627 help 591 help
628 Collect information on time spent by 592 Collect information on time spent by a task waiting for system
629 resources like cpu, synchronous bloc 593 resources like cpu, synchronous block I/O completion and swapping
630 in pages. Such statistics can help i 594 in pages. Such statistics can help in setting a task's priorities
631 relative to other tasks for cpu, io, 595 relative to other tasks for cpu, io, rss limits etc.
632 596
633 Say N if unsure. 597 Say N if unsure.
634 598
635 config TASK_XACCT 599 config TASK_XACCT
636 bool "Enable extended accounting over 600 bool "Enable extended accounting over taskstats"
637 depends on TASKSTATS 601 depends on TASKSTATS
638 help 602 help
639 Collect extended task accounting dat 603 Collect extended task accounting data and send the data
640 to userland for processing over the 604 to userland for processing over the taskstats interface.
641 605
642 Say N if unsure. 606 Say N if unsure.
643 607
644 config TASK_IO_ACCOUNTING 608 config TASK_IO_ACCOUNTING
645 bool "Enable per-task storage I/O acco 609 bool "Enable per-task storage I/O accounting"
646 depends on TASK_XACCT 610 depends on TASK_XACCT
647 help 611 help
648 Collect information on the number of 612 Collect information on the number of bytes of storage I/O which this
649 task has caused. 613 task has caused.
650 614
651 Say N if unsure. 615 Say N if unsure.
652 616
653 config PSI 617 config PSI
654 bool "Pressure stall information track 618 bool "Pressure stall information tracking"
655 select KERNFS <<
656 help 619 help
657 Collect metrics that indicate how ov 620 Collect metrics that indicate how overcommitted the CPU, memory,
658 and IO capacity are in the system. 621 and IO capacity are in the system.
659 622
660 If you say Y here, the kernel will c 623 If you say Y here, the kernel will create /proc/pressure/ with the
661 pressure statistics files cpu, memor 624 pressure statistics files cpu, memory, and io. These will indicate
662 the share of walltime in which some 625 the share of walltime in which some or all tasks in the system are
663 delayed due to contention of the res 626 delayed due to contention of the respective resource.
664 627
665 In kernels with cgroup support, cgro 628 In kernels with cgroup support, cgroups (cgroup2 only) will
666 have cpu.pressure, memory.pressure, 629 have cpu.pressure, memory.pressure, and io.pressure files,
667 which aggregate pressure stalls for 630 which aggregate pressure stalls for the grouped tasks only.
668 631
669 For more details see Documentation/a 632 For more details see Documentation/accounting/psi.rst.
670 633
671 Say N if unsure. 634 Say N if unsure.
672 635
673 config PSI_DEFAULT_DISABLED 636 config PSI_DEFAULT_DISABLED
674 bool "Require boot parameter to enable 637 bool "Require boot parameter to enable pressure stall information tracking"
675 default n 638 default n
676 depends on PSI 639 depends on PSI
677 help 640 help
678 If set, pressure stall information t 641 If set, pressure stall information tracking will be disabled
679 per default but can be enabled throu 642 per default but can be enabled through passing psi=1 on the
680 kernel commandline during boot. 643 kernel commandline during boot.
681 644
682 This feature adds some code to the t 645 This feature adds some code to the task wakeup and sleep
683 paths of the scheduler. The overhead 646 paths of the scheduler. The overhead is too low to affect
684 common scheduling-intense workloads 647 common scheduling-intense workloads in practice (such as
685 webservers, memcache), but it does s 648 webservers, memcache), but it does show up in artificial
686 scheduler stress tests, such as hack 649 scheduler stress tests, such as hackbench.
687 650
688 If you are paranoid and not sure wha 651 If you are paranoid and not sure what the kernel will be
689 used for, say Y. 652 used for, say Y.
690 653
691 Say N if unsure. 654 Say N if unsure.
692 655
693 endmenu # "CPU/Task time and stats accounting" 656 endmenu # "CPU/Task time and stats accounting"
694 657
695 config CPU_ISOLATION 658 config CPU_ISOLATION
696 bool "CPU isolation" 659 bool "CPU isolation"
697 depends on SMP || COMPILE_TEST 660 depends on SMP || COMPILE_TEST
698 default y 661 default y
699 help 662 help
700 Make sure that CPUs running critical 663 Make sure that CPUs running critical tasks are not disturbed by
701 any source of "noise" such as unboun 664 any source of "noise" such as unbound workqueues, timers, kthreads...
702 Unbound jobs get offloaded to housek 665 Unbound jobs get offloaded to housekeeping CPUs. This is driven by
703 the "isolcpus=" boot parameter. 666 the "isolcpus=" boot parameter.
704 667
705 Say Y if unsure. 668 Say Y if unsure.
706 669
707 source "kernel/rcu/Kconfig" 670 source "kernel/rcu/Kconfig"
708 671
>> 672 config BUILD_BIN2C
>> 673 bool
>> 674 default n
>> 675
709 config IKCONFIG 676 config IKCONFIG
710 tristate "Kernel .config support" 677 tristate "Kernel .config support"
711 help 678 help
712 This option enables the complete Lin 679 This option enables the complete Linux kernel ".config" file
713 contents to be saved in the kernel. 680 contents to be saved in the kernel. It provides documentation
714 of which kernel options are used in 681 of which kernel options are used in a running kernel or in an
715 on-disk kernel. This information ca 682 on-disk kernel. This information can be extracted from the kernel
716 image file with the script scripts/e 683 image file with the script scripts/extract-ikconfig and used as
717 input to rebuild the current kernel 684 input to rebuild the current kernel or to build another kernel.
718 It can also be extracted from a runn 685 It can also be extracted from a running kernel by reading
719 /proc/config.gz if enabled (below). 686 /proc/config.gz if enabled (below).
720 687
721 config IKCONFIG_PROC 688 config IKCONFIG_PROC
722 bool "Enable access to .config through 689 bool "Enable access to .config through /proc/config.gz"
723 depends on IKCONFIG && PROC_FS 690 depends on IKCONFIG && PROC_FS
724 help 691 help
725 This option enables access to the ke 692 This option enables access to the kernel configuration file
726 through /proc/config.gz. 693 through /proc/config.gz.
727 694
728 config IKHEADERS 695 config IKHEADERS
729 tristate "Enable kernel headers throug 696 tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz"
730 depends on SYSFS 697 depends on SYSFS
731 help 698 help
732 This option enables access to the in 699 This option enables access to the in-kernel headers that are generated during
733 the build process. These can be used 700 the build process. These can be used to build eBPF tracing programs,
734 or similar programs. If you build t 701 or similar programs. If you build the headers as a module, a module called
735 kheaders.ko is built which can be lo 702 kheaders.ko is built which can be loaded on-demand to get access to headers.
736 703
737 config LOG_BUF_SHIFT 704 config LOG_BUF_SHIFT
738 int "Kernel log buffer size (16 => 64K 705 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
739 range 12 25 706 range 12 25
740 default 17 707 default 17
741 depends on PRINTK 708 depends on PRINTK
742 help 709 help
743 Select the minimal kernel log buffer 710 Select the minimal kernel log buffer size as a power of 2.
744 The final size is affected by LOG_CP 711 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
745 parameter, see below. Any higher siz 712 parameter, see below. Any higher size also might be forced
746 by "log_buf_len" boot parameter. 713 by "log_buf_len" boot parameter.
747 714
748 Examples: 715 Examples:
749 17 => 128 KB 716 17 => 128 KB
750 16 => 64 KB 717 16 => 64 KB
751 15 => 32 KB 718 15 => 32 KB
752 14 => 16 KB 719 14 => 16 KB
753 13 => 8 KB 720 13 => 8 KB
754 12 => 4 KB 721 12 => 4 KB
755 722
756 config LOG_CPU_MAX_BUF_SHIFT 723 config LOG_CPU_MAX_BUF_SHIFT
757 int "CPU kernel log buffer size contri 724 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
758 depends on SMP 725 depends on SMP
759 range 0 21 726 range 0 21
>> 727 default 12 if !BASE_SMALL
760 default 0 if BASE_SMALL 728 default 0 if BASE_SMALL
761 default 12 <<
762 depends on PRINTK 729 depends on PRINTK
763 help 730 help
764 This option allows to increase the d 731 This option allows to increase the default ring buffer size
765 according to the number of CPUs. The 732 according to the number of CPUs. The value defines the contribution
766 of each CPU as a power of 2. The use 733 of each CPU as a power of 2. The used space is typically only few
767 lines however it might be much more 734 lines however it might be much more when problems are reported,
768 e.g. backtraces. 735 e.g. backtraces.
769 736
770 The increased size means that a new 737 The increased size means that a new buffer has to be allocated and
771 the original static one is unused. I 738 the original static one is unused. It makes sense only on systems
772 with more CPUs. Therefore this value 739 with more CPUs. Therefore this value is used only when the sum of
773 contributions is greater than the ha 740 contributions is greater than the half of the default kernel ring
774 buffer as defined by LOG_BUF_SHIFT. 741 buffer as defined by LOG_BUF_SHIFT. The default values are set
775 so that more than 16 CPUs are needed 742 so that more than 16 CPUs are needed to trigger the allocation.
776 743
777 Also this option is ignored when "lo 744 Also this option is ignored when "log_buf_len" kernel parameter is
778 used as it forces an exact (power of 745 used as it forces an exact (power of two) size of the ring buffer.
779 746
780 The number of possible CPUs is used 747 The number of possible CPUs is used for this computation ignoring
781 hotplugging making the computation o 748 hotplugging making the computation optimal for the worst case
782 scenario while allowing a simple alg 749 scenario while allowing a simple algorithm to be used from bootup.
783 750
784 Examples shift values and their mean 751 Examples shift values and their meaning:
785 17 => 128 KB for each CPU 752 17 => 128 KB for each CPU
786 16 => 64 KB for each CPU 753 16 => 64 KB for each CPU
787 15 => 32 KB for each CPU 754 15 => 32 KB for each CPU
788 14 => 16 KB for each CPU 755 14 => 16 KB for each CPU
789 13 => 8 KB for each CPU 756 13 => 8 KB for each CPU
790 12 => 4 KB for each CPU 757 12 => 4 KB for each CPU
791 758
>> 759 config PRINTK_SAFE_LOG_BUF_SHIFT
>> 760 int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)"
>> 761 range 10 21
>> 762 default 13
>> 763 depends on PRINTK
>> 764 help
>> 765 Select the size of an alternate printk per-CPU buffer where messages
>> 766 printed from usafe contexts are temporary stored. One example would
>> 767 be NMI messages, another one - printk recursion. The messages are
>> 768 copied to the main log buffer in a safe context to avoid a deadlock.
>> 769 The value defines the size as a power of 2.
>> 770
>> 771 Those messages are rare and limited. The largest one is when
>> 772 a backtrace is printed. It usually fits into 4KB. Select
>> 773 8KB if you want to be on the safe side.
>> 774
>> 775 Examples:
>> 776 17 => 128 KB for each CPU
>> 777 16 => 64 KB for each CPU
>> 778 15 => 32 KB for each CPU
>> 779 14 => 16 KB for each CPU
>> 780 13 => 8 KB for each CPU
>> 781 12 => 4 KB for each CPU
>> 782
792 config PRINTK_INDEX 783 config PRINTK_INDEX
793 bool "Printk indexing debugfs interfac 784 bool "Printk indexing debugfs interface"
794 depends on PRINTK && DEBUG_FS 785 depends on PRINTK && DEBUG_FS
795 help 786 help
796 Add support for indexing of all prin 787 Add support for indexing of all printk formats known at compile time
797 at <debugfs>/printk/index/<module>. 788 at <debugfs>/printk/index/<module>.
798 789
799 This can be used as part of maintain 790 This can be used as part of maintaining daemons which monitor
800 /dev/kmsg, as it permits auditing th 791 /dev/kmsg, as it permits auditing the printk formats present in a
801 kernel, allowing detection of cases 792 kernel, allowing detection of cases where monitored printks are
802 changed or no longer present. 793 changed or no longer present.
803 794
804 There is no additional runtime cost 795 There is no additional runtime cost to printk with this enabled.
805 796
806 # 797 #
807 # Architectures with an unreliable sched_clock 798 # Architectures with an unreliable sched_clock() should select this:
808 # 799 #
809 config HAVE_UNSTABLE_SCHED_CLOCK 800 config HAVE_UNSTABLE_SCHED_CLOCK
810 bool 801 bool
811 802
812 config GENERIC_SCHED_CLOCK 803 config GENERIC_SCHED_CLOCK
813 bool 804 bool
814 805
815 menu "Scheduler features" 806 menu "Scheduler features"
816 807
817 config UCLAMP_TASK 808 config UCLAMP_TASK
818 bool "Enable utilization clamping for 809 bool "Enable utilization clamping for RT/FAIR tasks"
819 depends on CPU_FREQ_GOV_SCHEDUTIL 810 depends on CPU_FREQ_GOV_SCHEDUTIL
820 help 811 help
821 This feature enables the scheduler t 812 This feature enables the scheduler to track the clamped utilization
822 of each CPU based on RUNNABLE tasks 813 of each CPU based on RUNNABLE tasks scheduled on that CPU.
823 814
824 With this option, the user can speci 815 With this option, the user can specify the min and max CPU
825 utilization allowed for RUNNABLE tas 816 utilization allowed for RUNNABLE tasks. The max utilization defines
826 the maximum frequency a task should 817 the maximum frequency a task should use while the min utilization
827 defines the minimum frequency it sho 818 defines the minimum frequency it should use.
828 819
829 Both min and max utilization clamp v 820 Both min and max utilization clamp values are hints to the scheduler,
830 aiming at improving its frequency se 821 aiming at improving its frequency selection policy, but they do not
831 enforce or grant any specific bandwi 822 enforce or grant any specific bandwidth for tasks.
832 823
833 If in doubt, say N. 824 If in doubt, say N.
834 825
835 config UCLAMP_BUCKETS_COUNT 826 config UCLAMP_BUCKETS_COUNT
836 int "Number of supported utilization c 827 int "Number of supported utilization clamp buckets"
837 range 5 20 828 range 5 20
838 default 5 829 default 5
839 depends on UCLAMP_TASK 830 depends on UCLAMP_TASK
840 help 831 help
841 Defines the number of clamp buckets 832 Defines the number of clamp buckets to use. The range of each bucket
842 will be SCHED_CAPACITY_SCALE/UCLAMP_ 833 will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the
843 number of clamp buckets the finer th 834 number of clamp buckets the finer their granularity and the higher
844 the precision of clamping aggregatio 835 the precision of clamping aggregation and tracking at run-time.
845 836
846 For example, with the minimum config 837 For example, with the minimum configuration value we will have 5
847 clamp buckets tracking 20% utilizati 838 clamp buckets tracking 20% utilization each. A 25% boosted tasks will
848 be refcounted in the [20..39]% bucke 839 be refcounted in the [20..39]% bucket and will set the bucket clamp
849 effective value to 25%. 840 effective value to 25%.
850 If a second 30% boosted task should 841 If a second 30% boosted task should be co-scheduled on the same CPU,
851 that task will be refcounted in the 842 that task will be refcounted in the same bucket of the first task and
852 it will boost the bucket clamp effec 843 it will boost the bucket clamp effective value to 30%.
853 The clamp effective value of a bucke 844 The clamp effective value of a bucket is reset to its nominal value
854 (20% in the example above) when ther 845 (20% in the example above) when there are no more tasks refcounted in
855 that bucket. 846 that bucket.
856 847
857 An additional boost/capping margin c 848 An additional boost/capping margin can be added to some tasks. In the
858 example above the 25% task will be b 849 example above the 25% task will be boosted to 30% until it exits the
859 CPU. If that should be considered no 850 CPU. If that should be considered not acceptable on certain systems,
860 it's always possible to reduce the m 851 it's always possible to reduce the margin by increasing the number of
861 clamp buckets to trade off used memo 852 clamp buckets to trade off used memory for run-time tracking
862 precision. 853 precision.
863 854
864 If in doubt, use the default value. 855 If in doubt, use the default value.
865 856
866 endmenu 857 endmenu
867 858
868 # 859 #
869 # For architectures that want to enable the su 860 # For architectures that want to enable the support for NUMA-affine scheduler
870 # balancing logic: 861 # balancing logic:
871 # 862 #
872 config ARCH_SUPPORTS_NUMA_BALANCING 863 config ARCH_SUPPORTS_NUMA_BALANCING
873 bool 864 bool
874 865
875 # 866 #
876 # For architectures that prefer to flush all T 867 # For architectures that prefer to flush all TLBs after a number of pages
877 # are unmapped instead of sending one IPI per 868 # are unmapped instead of sending one IPI per page to flush. The architecture
878 # must provide guarantees on what happens if a 869 # must provide guarantees on what happens if a clean TLB cache entry is
879 # written after the unmap. Details are in mm/r 870 # written after the unmap. Details are in mm/rmap.c near the check for
880 # should_defer_flush. The architecture should 871 # should_defer_flush. The architecture should also consider if the full flush
881 # and the refill costs are offset by the savin 872 # and the refill costs are offset by the savings of sending fewer IPIs.
882 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 873 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
883 bool 874 bool
884 875
885 config CC_HAS_INT128 876 config CC_HAS_INT128
886 def_bool !$(cc-option,$(m64-flag) -D__ 877 def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT
887 878
888 config CC_IMPLICIT_FALLTHROUGH 879 config CC_IMPLICIT_FALLTHROUGH
889 string 880 string
890 default "-Wimplicit-fallthrough=5" if 881 default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5)
891 default "-Wimplicit-fallthrough" if CC 882 default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough)
892 883
893 # Currently, disable gcc-10+ array-bounds glob !! 884 # Currently, disable gcc-12 array-bounds globally.
894 # It's still broken in gcc-13, so no upper bou !! 885 # We may want to target only particular configurations some day.
895 config GCC10_NO_ARRAY_BOUNDS !! 886 config GCC12_NO_ARRAY_BOUNDS
896 def_bool y 887 def_bool y
897 888
898 config CC_NO_ARRAY_BOUNDS 889 config CC_NO_ARRAY_BOUNDS
899 bool 890 bool
900 default y if CC_IS_GCC && GCC_VERSION !! 891 default y if CC_IS_GCC && GCC_VERSION >= 120000 && GCC_VERSION < 130000 && GCC12_NO_ARRAY_BOUNDS
901 <<
902 # Currently, disable -Wstringop-overflow for G <<
903 config GCC_NO_STRINGOP_OVERFLOW <<
904 def_bool y <<
905 <<
906 config CC_NO_STRINGOP_OVERFLOW <<
907 bool <<
908 default y if CC_IS_GCC && GCC_NO_STRIN <<
909 <<
910 config CC_STRINGOP_OVERFLOW <<
911 bool <<
912 default y if CC_IS_GCC && !CC_NO_STRIN <<
913 892
914 # 893 #
915 # For architectures that know their GCC __int1 894 # For architectures that know their GCC __int128 support is sound
916 # 895 #
917 config ARCH_SUPPORTS_INT128 896 config ARCH_SUPPORTS_INT128
918 bool 897 bool
919 898
920 # For architectures that (ab)use NUMA to repre 899 # For architectures that (ab)use NUMA to represent different memory regions
921 # all cpu-local but of different latencies, su 900 # all cpu-local but of different latencies, such as SuperH.
922 # 901 #
923 config ARCH_WANT_NUMA_VARIABLE_LOCALITY 902 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
924 bool 903 bool
925 904
926 config NUMA_BALANCING 905 config NUMA_BALANCING
927 bool "Memory placement aware NUMA sche 906 bool "Memory placement aware NUMA scheduler"
928 depends on ARCH_SUPPORTS_NUMA_BALANCIN 907 depends on ARCH_SUPPORTS_NUMA_BALANCING
929 depends on !ARCH_WANT_NUMA_VARIABLE_LO 908 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
930 depends on SMP && NUMA && MIGRATION && 909 depends on SMP && NUMA && MIGRATION && !PREEMPT_RT
931 help 910 help
932 This option adds support for automat 911 This option adds support for automatic NUMA aware memory/task placement.
933 The mechanism is quite primitive and 912 The mechanism is quite primitive and is based on migrating memory when
934 it has references to the node the ta 913 it has references to the node the task is running on.
935 914
936 This system will be inactive on UMA 915 This system will be inactive on UMA systems.
937 916
938 config NUMA_BALANCING_DEFAULT_ENABLED 917 config NUMA_BALANCING_DEFAULT_ENABLED
939 bool "Automatically enable NUMA aware 918 bool "Automatically enable NUMA aware memory/task placement"
940 default y 919 default y
941 depends on NUMA_BALANCING 920 depends on NUMA_BALANCING
942 help 921 help
943 If set, automatic NUMA balancing wil 922 If set, automatic NUMA balancing will be enabled if running on a NUMA
944 machine. 923 machine.
945 924
946 config SLAB_OBJ_EXT <<
947 bool <<
948 <<
949 menuconfig CGROUPS 925 menuconfig CGROUPS
950 bool "Control Group support" 926 bool "Control Group support"
951 select KERNFS 927 select KERNFS
952 help 928 help
953 This option adds support for groupin 929 This option adds support for grouping sets of processes together, for
954 use with process control subsystems 930 use with process control subsystems such as Cpusets, CFS, memory
955 controls or device isolation. 931 controls or device isolation.
956 See 932 See
957 - Documentation/scheduler/sche 933 - Documentation/scheduler/sched-design-CFS.rst (CFS)
958 - Documentation/admin-guide/cg 934 - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation
959 and 935 and resource control)
960 936
961 Say N if unsure. 937 Say N if unsure.
962 938
963 if CGROUPS 939 if CGROUPS
964 940
965 config PAGE_COUNTER 941 config PAGE_COUNTER
966 bool 942 bool
967 943
968 config CGROUP_FAVOR_DYNMODS 944 config CGROUP_FAVOR_DYNMODS
969 bool "Favor dynamic modification laten 945 bool "Favor dynamic modification latency reduction by default"
970 help 946 help
971 This option enables the "favordynmod 947 This option enables the "favordynmods" mount option by default
972 which reduces the latencies of dynam 948 which reduces the latencies of dynamic cgroup modifications such
973 as task migrations and controller on 949 as task migrations and controller on/offs at the cost of making
974 hot path operations such as forks an 950 hot path operations such as forks and exits more expensive.
975 951
976 Say N if unsure. 952 Say N if unsure.
977 953
978 config MEMCG 954 config MEMCG
979 bool "Memory controller" 955 bool "Memory controller"
980 select PAGE_COUNTER 956 select PAGE_COUNTER
981 select EVENTFD 957 select EVENTFD
982 select SLAB_OBJ_EXT <<
983 help 958 help
984 Provides control over the memory foo 959 Provides control over the memory footprint of tasks in a cgroup.
985 960
986 config MEMCG_V1 !! 961 config MEMCG_SWAP
987 bool "Legacy cgroup v1 memory controll !! 962 bool
988 depends on MEMCG !! 963 depends on MEMCG && SWAP
989 default n !! 964 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 965
1001 Say N if unsure. !! 966 config MEMCG_KMEM
>> 967 bool
>> 968 depends on MEMCG && !SLOB
>> 969 default y
1002 970
1003 config BLK_CGROUP 971 config BLK_CGROUP
1004 bool "IO controller" 972 bool "IO controller"
1005 depends on BLOCK 973 depends on BLOCK
1006 default n 974 default n
1007 help 975 help
1008 Generic block IO controller cgroup in 976 Generic block IO controller cgroup interface. This is the common
1009 cgroup interface which should be used 977 cgroup interface which should be used by various IO controlling
1010 policies. 978 policies.
1011 979
1012 Currently, CFQ IO scheduler uses it t 980 Currently, CFQ IO scheduler uses it to recognize task groups and
1013 control disk bandwidth allocation (pr 981 control disk bandwidth allocation (proportional time slice allocation)
1014 to such task groups. It is also used 982 to such task groups. It is also used by bio throttling logic in
1015 block layer to implement upper limit 983 block layer to implement upper limit in IO rates on a device.
1016 984
1017 This option only enables generic Bloc 985 This option only enables generic Block IO controller infrastructure.
1018 One needs to also enable actual IO co 986 One needs to also enable actual IO controlling logic/policy. For
1019 enabling proportional weight division 987 enabling proportional weight division of disk bandwidth in CFQ, set
1020 CONFIG_BFQ_GROUP_IOSCHED=y; for enabl 988 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1021 CONFIG_BLK_DEV_THROTTLING=y. 989 CONFIG_BLK_DEV_THROTTLING=y.
1022 990
1023 See Documentation/admin-guide/cgroup- 991 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information.
1024 992
1025 config CGROUP_WRITEBACK 993 config CGROUP_WRITEBACK
1026 bool 994 bool
1027 depends on MEMCG && BLK_CGROUP 995 depends on MEMCG && BLK_CGROUP
1028 default y 996 default y
1029 997
1030 menuconfig CGROUP_SCHED 998 menuconfig CGROUP_SCHED
1031 bool "CPU controller" 999 bool "CPU controller"
1032 default n 1000 default n
1033 help 1001 help
1034 This feature lets CPU scheduler rec 1002 This feature lets CPU scheduler recognize task groups and control CPU
1035 bandwidth allocation to such task g 1003 bandwidth allocation to such task groups. It uses cgroups to group
1036 tasks. 1004 tasks.
1037 1005
1038 if CGROUP_SCHED 1006 if CGROUP_SCHED
1039 config GROUP_SCHED_WEIGHT <<
1040 def_bool n <<
1041 <<
1042 config FAIR_GROUP_SCHED 1007 config FAIR_GROUP_SCHED
1043 bool "Group scheduling for SCHED_OTHE 1008 bool "Group scheduling for SCHED_OTHER"
1044 depends on CGROUP_SCHED 1009 depends on CGROUP_SCHED
1045 select GROUP_SCHED_WEIGHT <<
1046 default CGROUP_SCHED 1010 default CGROUP_SCHED
1047 1011
1048 config CFS_BANDWIDTH 1012 config CFS_BANDWIDTH
1049 bool "CPU bandwidth provisioning for 1013 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1050 depends on FAIR_GROUP_SCHED 1014 depends on FAIR_GROUP_SCHED
1051 default n 1015 default n
1052 help 1016 help
1053 This option allows users to define 1017 This option allows users to define CPU bandwidth rates (limits) for
1054 tasks running within the fair group 1018 tasks running within the fair group scheduler. Groups with no limit
1055 set are considered to be unconstrai 1019 set are considered to be unconstrained and will run with no
1056 restriction. 1020 restriction.
1057 See Documentation/scheduler/sched-b 1021 See Documentation/scheduler/sched-bwc.rst for more information.
1058 1022
1059 config RT_GROUP_SCHED 1023 config RT_GROUP_SCHED
1060 bool "Group scheduling for SCHED_RR/F 1024 bool "Group scheduling for SCHED_RR/FIFO"
1061 depends on CGROUP_SCHED 1025 depends on CGROUP_SCHED
1062 default n 1026 default n
1063 help 1027 help
1064 This feature lets you explicitly al 1028 This feature lets you explicitly allocate real CPU bandwidth
1065 to task groups. If enabled, it will 1029 to task groups. If enabled, it will also make it impossible to
1066 schedule realtime tasks for non-roo 1030 schedule realtime tasks for non-root users until you allocate
1067 realtime bandwidth for them. 1031 realtime bandwidth for them.
1068 See Documentation/scheduler/sched-r 1032 See Documentation/scheduler/sched-rt-group.rst for more information.
1069 1033
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 1034 endif #CGROUP_SCHED
1077 1035
1078 config SCHED_MM_CID <<
1079 def_bool y <<
1080 depends on SMP && RSEQ <<
1081 <<
1082 config UCLAMP_TASK_GROUP 1036 config UCLAMP_TASK_GROUP
1083 bool "Utilization clamping per group 1037 bool "Utilization clamping per group of tasks"
1084 depends on CGROUP_SCHED 1038 depends on CGROUP_SCHED
1085 depends on UCLAMP_TASK 1039 depends on UCLAMP_TASK
1086 default n 1040 default n
1087 help 1041 help
1088 This feature enables the scheduler 1042 This feature enables the scheduler to track the clamped utilization
1089 of each CPU based on RUNNABLE tasks 1043 of each CPU based on RUNNABLE tasks currently scheduled on that CPU.
1090 1044
1091 When this option is enabled, the us 1045 When this option is enabled, the user can specify a min and max
1092 CPU bandwidth which is allowed for 1046 CPU bandwidth which is allowed for each single task in a group.
1093 The max bandwidth allows to clamp t 1047 The max bandwidth allows to clamp the maximum frequency a task
1094 can use, while the min bandwidth al 1048 can use, while the min bandwidth allows to define a minimum
1095 frequency a task will always use. 1049 frequency a task will always use.
1096 1050
1097 When task group based utilization c 1051 When task group based utilization clamping is enabled, an eventually
1098 specified task-specific clamp value 1052 specified task-specific clamp value is constrained by the cgroup
1099 specified clamp value. Both minimum 1053 specified clamp value. Both minimum and maximum task clamping cannot
1100 be bigger than the corresponding cl 1054 be bigger than the corresponding clamping defined at task group level.
1101 1055
1102 If in doubt, say N. 1056 If in doubt, say N.
1103 1057
1104 config CGROUP_PIDS 1058 config CGROUP_PIDS
1105 bool "PIDs controller" 1059 bool "PIDs controller"
1106 help 1060 help
1107 Provides enforcement of process num 1061 Provides enforcement of process number limits in the scope of a
1108 cgroup. Any attempt to fork more pr 1062 cgroup. Any attempt to fork more processes than is allowed in the
1109 cgroup will fail. PIDs are fundamen 1063 cgroup will fail. PIDs are fundamentally a global resource because it
1110 is fairly trivial to reach PID exha 1064 is fairly trivial to reach PID exhaustion before you reach even a
1111 conservative kmemcg limit. As a res 1065 conservative kmemcg limit. As a result, it is possible to grind a
1112 system to halt without being limite 1066 system to halt without being limited by other cgroup policies. The
1113 PIDs controller is designed to stop 1067 PIDs controller is designed to stop this from happening.
1114 1068
1115 It should be noted that organisatio 1069 It should be noted that organisational operations (such as attaching
1116 to a cgroup hierarchy) will *not* b 1070 to a cgroup hierarchy) will *not* be blocked by the PIDs controller,
1117 since the PIDs limit only affects a 1071 since the PIDs limit only affects a process's ability to fork, not to
1118 attach to a cgroup. 1072 attach to a cgroup.
1119 1073
1120 config CGROUP_RDMA 1074 config CGROUP_RDMA
1121 bool "RDMA controller" 1075 bool "RDMA controller"
1122 help 1076 help
1123 Provides enforcement of RDMA resour 1077 Provides enforcement of RDMA resources defined by IB stack.
1124 It is fairly easy for consumers to 1078 It is fairly easy for consumers to exhaust RDMA resources, which
1125 can result into resource unavailabi 1079 can result into resource unavailability to other consumers.
1126 RDMA controller is designed to stop 1080 RDMA controller is designed to stop this from happening.
1127 Attaching processes with active RDM 1081 Attaching processes with active RDMA resources to the cgroup
1128 hierarchy is allowed even if can cr 1082 hierarchy is allowed even if can cross the hierarchy's limit.
1129 1083
1130 config CGROUP_FREEZER 1084 config CGROUP_FREEZER
1131 bool "Freezer controller" 1085 bool "Freezer controller"
1132 help 1086 help
1133 Provides a way to freeze and unfree 1087 Provides a way to freeze and unfreeze all tasks in a
1134 cgroup. 1088 cgroup.
1135 1089
1136 This option affects the ORIGINAL cg 1090 This option affects the ORIGINAL cgroup interface. The cgroup2 memory
1137 controller includes important in-ke 1091 controller includes important in-kernel memory consumers per default.
1138 1092
1139 If you're using cgroup2, say N. 1093 If you're using cgroup2, say N.
1140 1094
1141 config CGROUP_HUGETLB 1095 config CGROUP_HUGETLB
1142 bool "HugeTLB controller" 1096 bool "HugeTLB controller"
1143 depends on HUGETLB_PAGE 1097 depends on HUGETLB_PAGE
1144 select PAGE_COUNTER 1098 select PAGE_COUNTER
1145 default n 1099 default n
1146 help 1100 help
1147 Provides a cgroup controller for Hu 1101 Provides a cgroup controller for HugeTLB pages.
1148 When you enable this, you can put a 1102 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1149 The limit is enforced during page f 1103 The limit is enforced during page fault. Since HugeTLB doesn't
1150 support page reclaim, enforcing the 1104 support page reclaim, enforcing the limit at page fault time implies
1151 that, the application will get SIGB 1105 that, the application will get SIGBUS signal if it tries to access
1152 HugeTLB pages beyond its limit. Thi 1106 HugeTLB pages beyond its limit. This requires the application to know
1153 beforehand how much HugeTLB pages i 1107 beforehand how much HugeTLB pages it would require for its use. The
1154 control group is tracked in the thi 1108 control group is tracked in the third page lru pointer. This means
1155 that we cannot use the controller w 1109 that we cannot use the controller with huge page less than 3 pages.
1156 1110
1157 config CPUSETS 1111 config CPUSETS
1158 bool "Cpuset controller" 1112 bool "Cpuset controller"
1159 depends on SMP 1113 depends on SMP
1160 help 1114 help
1161 This option will let you create and 1115 This option will let you create and manage CPUSETs which
1162 allow dynamically partitioning a sy 1116 allow dynamically partitioning a system into sets of CPUs and
1163 Memory Nodes and assigning tasks to 1117 Memory Nodes and assigning tasks to run only within those sets.
1164 This is primarily useful on large S 1118 This is primarily useful on large SMP or NUMA systems.
1165 1119
1166 Say N if unsure. 1120 Say N if unsure.
1167 1121
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 1122 config PROC_PID_CPUSET
1182 bool "Include legacy /proc/<pid>/cpus 1123 bool "Include legacy /proc/<pid>/cpuset file"
1183 depends on CPUSETS 1124 depends on CPUSETS
1184 default y 1125 default y
1185 1126
1186 config CGROUP_DEVICE 1127 config CGROUP_DEVICE
1187 bool "Device controller" 1128 bool "Device controller"
1188 help 1129 help
1189 Provides a cgroup controller implem 1130 Provides a cgroup controller implementing whitelists for
1190 devices which a process in the cgro 1131 devices which a process in the cgroup can mknod or open.
1191 1132
1192 config CGROUP_CPUACCT 1133 config CGROUP_CPUACCT
1193 bool "Simple CPU accounting controlle 1134 bool "Simple CPU accounting controller"
1194 help 1135 help
1195 Provides a simple controller for mo 1136 Provides a simple controller for monitoring the
1196 total CPU consumed by the tasks in 1137 total CPU consumed by the tasks in a cgroup.
1197 1138
1198 config CGROUP_PERF 1139 config CGROUP_PERF
1199 bool "Perf controller" 1140 bool "Perf controller"
1200 depends on PERF_EVENTS 1141 depends on PERF_EVENTS
1201 help 1142 help
1202 This option extends the perf per-cp 1143 This option extends the perf per-cpu mode to restrict monitoring
1203 to threads which belong to the cgro 1144 to threads which belong to the cgroup specified and run on the
1204 designated cpu. Or this can be use 1145 designated cpu. Or this can be used to have cgroup ID in samples
1205 so that it can monitor performance 1146 so that it can monitor performance events among cgroups.
1206 1147
1207 Say N if unsure. 1148 Say N if unsure.
1208 1149
1209 config CGROUP_BPF 1150 config CGROUP_BPF
1210 bool "Support for eBPF programs attac 1151 bool "Support for eBPF programs attached to cgroups"
1211 depends on BPF_SYSCALL 1152 depends on BPF_SYSCALL
1212 select SOCK_CGROUP_DATA 1153 select SOCK_CGROUP_DATA
1213 help 1154 help
1214 Allow attaching eBPF programs to a 1155 Allow attaching eBPF programs to a cgroup using the bpf(2)
1215 syscall command BPF_PROG_ATTACH. 1156 syscall command BPF_PROG_ATTACH.
1216 1157
1217 In which context these programs are 1158 In which context these programs are accessed depends on the type
1218 of attachment. For instance, progra 1159 of attachment. For instance, programs that are attached using
1219 BPF_CGROUP_INET_INGRESS will be exe 1160 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
1220 inet sockets. 1161 inet sockets.
1221 1162
1222 config CGROUP_MISC 1163 config CGROUP_MISC
1223 bool "Misc resource controller" 1164 bool "Misc resource controller"
1224 default n 1165 default n
1225 help 1166 help
1226 Provides a controller for miscellan 1167 Provides a controller for miscellaneous resources on a host.
1227 1168
1228 Miscellaneous scalar resources are 1169 Miscellaneous scalar resources are the resources on the host system
1229 which cannot be abstracted like the 1170 which cannot be abstracted like the other cgroups. This controller
1230 tracks and limits the miscellaneous 1171 tracks and limits the miscellaneous resources used by a process
1231 attached to a cgroup hierarchy. 1172 attached to a cgroup hierarchy.
1232 1173
1233 For more information, please check 1174 For more information, please check misc cgroup section in
1234 /Documentation/admin-guide/cgroup-v 1175 /Documentation/admin-guide/cgroup-v2.rst.
1235 1176
1236 config CGROUP_DEBUG 1177 config CGROUP_DEBUG
1237 bool "Debug controller" 1178 bool "Debug controller"
1238 default n 1179 default n
1239 depends on DEBUG_KERNEL 1180 depends on DEBUG_KERNEL
1240 help 1181 help
1241 This option enables a simple contro 1182 This option enables a simple controller that exports
1242 debugging information about the cgr 1183 debugging information about the cgroups framework. This
1243 controller is for control cgroup de 1184 controller is for control cgroup debugging only. Its
1244 interfaces are not stable. 1185 interfaces are not stable.
1245 1186
1246 Say N. 1187 Say N.
1247 1188
1248 config SOCK_CGROUP_DATA 1189 config SOCK_CGROUP_DATA
1249 bool 1190 bool
1250 default n 1191 default n
1251 1192
1252 endif # CGROUPS 1193 endif # CGROUPS
1253 1194
1254 menuconfig NAMESPACES 1195 menuconfig NAMESPACES
1255 bool "Namespaces support" if EXPERT 1196 bool "Namespaces support" if EXPERT
1256 depends on MULTIUSER 1197 depends on MULTIUSER
1257 default !EXPERT 1198 default !EXPERT
1258 help 1199 help
1259 Provides the way to make tasks work 1200 Provides the way to make tasks work with different objects using
1260 the same id. For example same IPC i 1201 the same id. For example same IPC id may refer to different objects
1261 or same user id or pid may refer to 1202 or same user id or pid may refer to different tasks when used in
1262 different namespaces. 1203 different namespaces.
1263 1204
1264 if NAMESPACES 1205 if NAMESPACES
1265 1206
1266 config UTS_NS 1207 config UTS_NS
1267 bool "UTS namespace" 1208 bool "UTS namespace"
1268 default y 1209 default y
1269 help 1210 help
1270 In this namespace tasks see differe 1211 In this namespace tasks see different info provided with the
1271 uname() system call 1212 uname() system call
1272 1213
1273 config TIME_NS 1214 config TIME_NS
1274 bool "TIME namespace" 1215 bool "TIME namespace"
1275 depends on GENERIC_VDSO_TIME_NS 1216 depends on GENERIC_VDSO_TIME_NS
1276 default y 1217 default y
1277 help 1218 help
1278 In this namespace boottime and mono 1219 In this namespace boottime and monotonic clocks can be set.
1279 The time will keep going with the s 1220 The time will keep going with the same pace.
1280 1221
1281 config IPC_NS 1222 config IPC_NS
1282 bool "IPC namespace" 1223 bool "IPC namespace"
1283 depends on (SYSVIPC || POSIX_MQUEUE) 1224 depends on (SYSVIPC || POSIX_MQUEUE)
1284 default y 1225 default y
1285 help 1226 help
1286 In this namespace tasks work with I 1227 In this namespace tasks work with IPC ids which correspond to
1287 different IPC objects in different 1228 different IPC objects in different namespaces.
1288 1229
1289 config USER_NS 1230 config USER_NS
1290 bool "User namespace" 1231 bool "User namespace"
1291 default n 1232 default n
1292 help 1233 help
1293 This allows containers, i.e. vserve 1234 This allows containers, i.e. vservers, to use user namespaces
1294 to provide different user info for 1235 to provide different user info for different servers.
1295 1236
1296 When user namespaces are enabled in 1237 When user namespaces are enabled in the kernel it is
1297 recommended that the MEMCG option a 1238 recommended that the MEMCG option also be enabled and that
1298 user-space use the memory control g 1239 user-space use the memory control groups to limit the amount
1299 of memory a memory unprivileged use 1240 of memory a memory unprivileged users can use.
1300 1241
1301 If unsure, say N. 1242 If unsure, say N.
1302 1243
1303 config PID_NS 1244 config PID_NS
1304 bool "PID Namespaces" 1245 bool "PID Namespaces"
1305 default y 1246 default y
1306 help 1247 help
1307 Support process id namespaces. Thi 1248 Support process id namespaces. This allows having multiple
1308 processes with the same pid as long 1249 processes with the same pid as long as they are in different
1309 pid namespaces. This is a building 1250 pid namespaces. This is a building block of containers.
1310 1251
1311 config NET_NS 1252 config NET_NS
1312 bool "Network namespace" 1253 bool "Network namespace"
1313 depends on NET 1254 depends on NET
1314 default y 1255 default y
1315 help 1256 help
1316 Allow user space to create what app 1257 Allow user space to create what appear to be multiple instances
1317 of the network stack. 1258 of the network stack.
1318 1259
1319 endif # NAMESPACES 1260 endif # NAMESPACES
1320 1261
1321 config CHECKPOINT_RESTORE 1262 config CHECKPOINT_RESTORE
1322 bool "Checkpoint/restore support" 1263 bool "Checkpoint/restore support"
1323 depends on PROC_FS <<
1324 select PROC_CHILDREN 1264 select PROC_CHILDREN
1325 select KCMP 1265 select KCMP
1326 default n 1266 default n
1327 help 1267 help
1328 Enables additional kernel features 1268 Enables additional kernel features in a sake of checkpoint/restore.
1329 In particular it adds auxiliary prc 1269 In particular it adds auxiliary prctl codes to setup process text,
1330 data and heap segment sizes, and a 1270 data and heap segment sizes, and a few additional /proc filesystem
1331 entries. 1271 entries.
1332 1272
1333 If unsure, say N here. 1273 If unsure, say N here.
1334 1274
1335 config SCHED_AUTOGROUP 1275 config SCHED_AUTOGROUP
1336 bool "Automatic process group schedul 1276 bool "Automatic process group scheduling"
1337 select CGROUPS 1277 select CGROUPS
1338 select CGROUP_SCHED 1278 select CGROUP_SCHED
1339 select FAIR_GROUP_SCHED 1279 select FAIR_GROUP_SCHED
1340 help 1280 help
1341 This option optimizes the scheduler 1281 This option optimizes the scheduler for common desktop workloads by
1342 automatically creating and populati 1282 automatically creating and populating task groups. This separation
1343 of workloads isolates aggressive CP 1283 of workloads isolates aggressive CPU burners (like build jobs) from
1344 desktop applications. Task group a 1284 desktop applications. Task group autogeneration is currently based
1345 upon task session. 1285 upon task session.
1346 1286
>> 1287 config SYSFS_DEPRECATED
>> 1288 bool "Enable deprecated sysfs features to support old userspace tools"
>> 1289 depends on SYSFS
>> 1290 default n
>> 1291 help
>> 1292 This option adds code that switches the layout of the "block" class
>> 1293 devices, to not show up in /sys/class/block/, but only in
>> 1294 /sys/block/.
>> 1295
>> 1296 This switch is only active when the sysfs.deprecated=1 boot option is
>> 1297 passed or the SYSFS_DEPRECATED_V2 option is set.
>> 1298
>> 1299 This option allows new kernels to run on old distributions and tools,
>> 1300 which might get confused by /sys/class/block/. Since 2007/2008 all
>> 1301 major distributions and tools handle this just fine.
>> 1302
>> 1303 Recent distributions and userspace tools after 2009/2010 depend on
>> 1304 the existence of /sys/class/block/, and will not work with this
>> 1305 option enabled.
>> 1306
>> 1307 Only if you are using a new kernel on an old distribution, you might
>> 1308 need to say Y here.
>> 1309
>> 1310 config SYSFS_DEPRECATED_V2
>> 1311 bool "Enable deprecated sysfs features by default"
>> 1312 default n
>> 1313 depends on SYSFS
>> 1314 depends on SYSFS_DEPRECATED
>> 1315 help
>> 1316 Enable deprecated sysfs by default.
>> 1317
>> 1318 See the CONFIG_SYSFS_DEPRECATED option for more details about this
>> 1319 option.
>> 1320
>> 1321 Only if you are using a new kernel on an old distribution, you might
>> 1322 need to say Y here. Even then, odds are you would not need it
>> 1323 enabled, you can always pass the boot option if absolutely necessary.
>> 1324
1347 config RELAY 1325 config RELAY
1348 bool "Kernel->user space relay suppor 1326 bool "Kernel->user space relay support (formerly relayfs)"
1349 select IRQ_WORK 1327 select IRQ_WORK
1350 help 1328 help
1351 This option enables support for rel 1329 This option enables support for relay interface support in
1352 certain file systems (such as debug 1330 certain file systems (such as debugfs).
1353 It is designed to provide an effici 1331 It is designed to provide an efficient mechanism for tools and
1354 facilities to relay large amounts o 1332 facilities to relay large amounts of data from kernel space to
1355 user space. 1333 user space.
1356 1334
1357 If unsure, say N. 1335 If unsure, say N.
1358 1336
1359 config BLK_DEV_INITRD 1337 config BLK_DEV_INITRD
1360 bool "Initial RAM filesystem and RAM 1338 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1361 help 1339 help
1362 The initial RAM filesystem is a ram 1340 The initial RAM filesystem is a ramfs which is loaded by the
1363 boot loader (loadlin or lilo) and t 1341 boot loader (loadlin or lilo) and that is mounted as root
1364 before the normal boot procedure. I 1342 before the normal boot procedure. It is typically used to
1365 load modules needed to mount the "r 1343 load modules needed to mount the "real" root file system,
1366 etc. See <file:Documentation/admin- 1344 etc. See <file:Documentation/admin-guide/initrd.rst> for details.
1367 1345
1368 If RAM disk support (BLK_DEV_RAM) i 1346 If RAM disk support (BLK_DEV_RAM) is also included, this
1369 also enables initial RAM disk (init 1347 also enables initial RAM disk (initrd) support and adds
1370 15 Kbytes (more on some other archi 1348 15 Kbytes (more on some other architectures) to the kernel size.
1371 1349
1372 If unsure say Y. 1350 If unsure say Y.
1373 1351
1374 if BLK_DEV_INITRD 1352 if BLK_DEV_INITRD
1375 1353
1376 source "usr/Kconfig" 1354 source "usr/Kconfig"
1377 1355
1378 endif 1356 endif
1379 1357
1380 config BOOT_CONFIG 1358 config BOOT_CONFIG
1381 bool "Boot config support" 1359 bool "Boot config support"
1382 select BLK_DEV_INITRD if !BOOT_CONFIG 1360 select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED
1383 help 1361 help
1384 Extra boot config allows system adm 1362 Extra boot config allows system admin to pass a config file as
1385 complemental extension of kernel cm 1363 complemental extension of kernel cmdline when booting.
1386 The boot config file must be attach 1364 The boot config file must be attached at the end of initramfs
1387 with checksum, size and magic word. 1365 with checksum, size and magic word.
1388 See <file:Documentation/admin-guide 1366 See <file:Documentation/admin-guide/bootconfig.rst> for details.
1389 1367
1390 If unsure, say Y. 1368 If unsure, say Y.
1391 1369
1392 config BOOT_CONFIG_FORCE <<
1393 bool "Force unconditional bootconfig <<
1394 depends on BOOT_CONFIG <<
1395 default y if BOOT_CONFIG_EMBED <<
1396 help <<
1397 With this Kconfig option set, BOOT_ <<
1398 out even when the "bootconfig" kern <<
1399 In fact, with this Kconfig option s <<
1400 make the kernel ignore the BOOT_CON <<
1401 parameters. <<
1402 <<
1403 If unsure, say N. <<
1404 <<
1405 config BOOT_CONFIG_EMBED 1370 config BOOT_CONFIG_EMBED
1406 bool "Embed bootconfig file in the ke 1371 bool "Embed bootconfig file in the kernel"
1407 depends on BOOT_CONFIG 1372 depends on BOOT_CONFIG
1408 help 1373 help
1409 Embed a bootconfig file given by BO 1374 Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the
1410 kernel. Usually, the bootconfig fil 1375 kernel. Usually, the bootconfig file is loaded with the initrd
1411 image. But if the system doesn't su 1376 image. But if the system doesn't support initrd, this option will
1412 help you by embedding a bootconfig 1377 help you by embedding a bootconfig file while building the kernel.
1413 1378
1414 If unsure, say N. 1379 If unsure, say N.
1415 1380
1416 config BOOT_CONFIG_EMBED_FILE 1381 config BOOT_CONFIG_EMBED_FILE
1417 string "Embedded bootconfig file path 1382 string "Embedded bootconfig file path"
1418 depends on BOOT_CONFIG_EMBED 1383 depends on BOOT_CONFIG_EMBED
1419 help 1384 help
1420 Specify a bootconfig file which wil 1385 Specify a bootconfig file which will be embedded to the kernel.
1421 This bootconfig will be used if the 1386 This bootconfig will be used if there is no initrd or no other
1422 bootconfig in the initrd. 1387 bootconfig in the initrd.
1423 1388
1424 config INITRAMFS_PRESERVE_MTIME 1389 config INITRAMFS_PRESERVE_MTIME
1425 bool "Preserve cpio archive mtimes in 1390 bool "Preserve cpio archive mtimes in initramfs"
1426 default y 1391 default y
1427 help 1392 help
1428 Each entry in an initramfs cpio arc 1393 Each entry in an initramfs cpio archive carries an mtime value. When
1429 enabled, extracted cpio items take 1394 enabled, extracted cpio items take this mtime, with directory mtime
1430 setting deferred until after creati 1395 setting deferred until after creation of any child entries.
1431 1396
1432 If unsure, say Y. 1397 If unsure, say Y.
1433 1398
1434 choice 1399 choice
1435 prompt "Compiler optimization level" 1400 prompt "Compiler optimization level"
1436 default CC_OPTIMIZE_FOR_PERFORMANCE 1401 default CC_OPTIMIZE_FOR_PERFORMANCE
1437 1402
1438 config CC_OPTIMIZE_FOR_PERFORMANCE 1403 config CC_OPTIMIZE_FOR_PERFORMANCE
1439 bool "Optimize for performance (-O2)" 1404 bool "Optimize for performance (-O2)"
1440 help 1405 help
1441 This is the default optimization le 1406 This is the default optimization level for the kernel, building
1442 with the "-O2" compiler flag for be 1407 with the "-O2" compiler flag for best performance and most
1443 helpful compile-time warnings. 1408 helpful compile-time warnings.
1444 1409
1445 config CC_OPTIMIZE_FOR_SIZE 1410 config CC_OPTIMIZE_FOR_SIZE
1446 bool "Optimize for size (-Os)" 1411 bool "Optimize for size (-Os)"
1447 help 1412 help
1448 Choosing this option will pass "-Os 1413 Choosing this option will pass "-Os" to your compiler resulting
1449 in a smaller kernel. 1414 in a smaller kernel.
1450 1415
1451 endchoice 1416 endchoice
1452 1417
1453 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1418 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1454 bool 1419 bool
1455 help 1420 help
1456 This requires that the arch annotat 1421 This requires that the arch annotates or otherwise protects
1457 its external entry points from bein 1422 its external entry points from being discarded. Linker scripts
1458 must also merge .text.*, .data.*, a 1423 must also merge .text.*, .data.*, and .bss.* correctly into
1459 output sections. Care must be taken 1424 output sections. Care must be taken not to pull in unrelated
1460 sections (e.g., '.text.init'). Typi 1425 sections (e.g., '.text.init'). Typically '.' in section names
1461 is used to distinguish them from la 1426 is used to distinguish them from label names / C identifiers.
1462 1427
1463 config LD_DEAD_CODE_DATA_ELIMINATION 1428 config LD_DEAD_CODE_DATA_ELIMINATION
1464 bool "Dead code and data elimination 1429 bool "Dead code and data elimination (EXPERIMENTAL)"
1465 depends on HAVE_LD_DEAD_CODE_DATA_ELI 1430 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1466 depends on EXPERT 1431 depends on EXPERT
1467 depends on $(cc-option,-ffunction-sec 1432 depends on $(cc-option,-ffunction-sections -fdata-sections)
1468 depends on $(ld-option,--gc-sections) 1433 depends on $(ld-option,--gc-sections)
1469 help 1434 help
1470 Enable this if you want to do dead 1435 Enable this if you want to do dead code and data elimination with
1471 the linker by compiling with -ffunc 1436 the linker by compiling with -ffunction-sections -fdata-sections,
1472 and linking with --gc-sections. 1437 and linking with --gc-sections.
1473 1438
1474 This can reduce on disk and in-memo 1439 This can reduce on disk and in-memory size of the kernel
1475 code and static data, particularly 1440 code and static data, particularly for small configs and
1476 on small systems. This has the poss 1441 on small systems. This has the possibility of introducing
1477 silently broken kernel if the requi 1442 silently broken kernel if the required annotations are not
1478 present. This option is not well te 1443 present. This option is not well tested yet, so use at your
1479 own risk. 1444 own risk.
1480 1445
1481 config LD_ORPHAN_WARN 1446 config LD_ORPHAN_WARN
1482 def_bool y 1447 def_bool y
1483 depends on ARCH_WANT_LD_ORPHAN_WARN 1448 depends on ARCH_WANT_LD_ORPHAN_WARN
1484 depends on $(ld-option,--orphan-handl 1449 depends on $(ld-option,--orphan-handling=warn)
1485 depends on $(ld-option,--orphan-handl <<
1486 <<
1487 config LD_ORPHAN_WARN_LEVEL <<
1488 string <<
1489 depends on LD_ORPHAN_WARN <<
1490 default "error" if WERROR <<
1491 default "warn" <<
1492 1450
1493 config SYSCTL 1451 config SYSCTL
1494 bool 1452 bool
1495 1453
1496 config HAVE_UID16 1454 config HAVE_UID16
1497 bool 1455 bool
1498 1456
1499 config SYSCTL_EXCEPTION_TRACE 1457 config SYSCTL_EXCEPTION_TRACE
1500 bool 1458 bool
1501 help 1459 help
1502 Enable support for /proc/sys/debug/ 1460 Enable support for /proc/sys/debug/exception-trace.
1503 1461
1504 config SYSCTL_ARCH_UNALIGN_NO_WARN 1462 config SYSCTL_ARCH_UNALIGN_NO_WARN
1505 bool 1463 bool
1506 help 1464 help
1507 Enable support for /proc/sys/kernel 1465 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1508 Allows arch to define/use @no_unali 1466 Allows arch to define/use @no_unaligned_warning to possibly warn
1509 about unaligned access emulation go 1467 about unaligned access emulation going on under the hood.
1510 1468
1511 config SYSCTL_ARCH_UNALIGN_ALLOW 1469 config SYSCTL_ARCH_UNALIGN_ALLOW
1512 bool 1470 bool
1513 help 1471 help
1514 Enable support for /proc/sys/kernel 1472 Enable support for /proc/sys/kernel/unaligned-trap
1515 Allows arches to define/use @unalig 1473 Allows arches to define/use @unaligned_enabled to runtime toggle
1516 the unaligned access emulation. 1474 the unaligned access emulation.
1517 see arch/parisc/kernel/unaligned.c 1475 see arch/parisc/kernel/unaligned.c for reference
1518 1476
1519 config HAVE_PCSPKR_PLATFORM 1477 config HAVE_PCSPKR_PLATFORM
1520 bool 1478 bool
1521 1479
>> 1480 # interpreter that classic socket filters depend on
>> 1481 config BPF
>> 1482 bool
>> 1483 select CRYPTO_LIB_SHA1
>> 1484
1522 menuconfig EXPERT 1485 menuconfig EXPERT
1523 bool "Configure standard kernel featu 1486 bool "Configure standard kernel features (expert users)"
1524 # Unhide debug options, to make the o 1487 # Unhide debug options, to make the on-by-default options visible
1525 select DEBUG_KERNEL 1488 select DEBUG_KERNEL
1526 help 1489 help
1527 This option allows certain base ker 1490 This option allows certain base kernel options and settings
1528 to be disabled or tweaked. This is 1491 to be disabled or tweaked. This is for specialized
1529 environments which can tolerate a " 1492 environments which can tolerate a "non-standard" kernel.
1530 Only use this if you really know wh 1493 Only use this if you really know what you are doing.
1531 1494
1532 config UID16 1495 config UID16
1533 bool "Enable 16-bit UID system calls" 1496 bool "Enable 16-bit UID system calls" if EXPERT
1534 depends on HAVE_UID16 && MULTIUSER 1497 depends on HAVE_UID16 && MULTIUSER
1535 default y 1498 default y
1536 help 1499 help
1537 This enables the legacy 16-bit UID 1500 This enables the legacy 16-bit UID syscall wrappers.
1538 1501
1539 config MULTIUSER 1502 config MULTIUSER
1540 bool "Multiple users, groups and capa 1503 bool "Multiple users, groups and capabilities support" if EXPERT
1541 default y 1504 default y
1542 help 1505 help
1543 This option enables support for non 1506 This option enables support for non-root users, groups and
1544 capabilities. 1507 capabilities.
1545 1508
1546 If you say N here, all processes wi 1509 If you say N here, all processes will run with UID 0, GID 0, and all
1547 possible capabilities. Saying N he 1510 possible capabilities. Saying N here also compiles out support for
1548 system calls related to UIDs, GIDs, 1511 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1549 setgid, and capset. 1512 setgid, and capset.
1550 1513
1551 If unsure, say Y here. 1514 If unsure, say Y here.
1552 1515
1553 config SGETMASK_SYSCALL 1516 config SGETMASK_SYSCALL
1554 bool "sgetmask/ssetmask syscalls supp 1517 bool "sgetmask/ssetmask syscalls support" if EXPERT
1555 default PARISC || M68K || PPC || MIPS !! 1518 def_bool PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH
1556 help 1519 help
1557 sys_sgetmask and sys_ssetmask are o 1520 sys_sgetmask and sys_ssetmask are obsolete system calls
1558 no longer supported in libc but sti 1521 no longer supported in libc but still enabled by default in some
1559 architectures. 1522 architectures.
1560 1523
1561 If unsure, leave the default option 1524 If unsure, leave the default option here.
1562 1525
1563 config SYSFS_SYSCALL 1526 config SYSFS_SYSCALL
1564 bool "Sysfs syscall support" if EXPER 1527 bool "Sysfs syscall support" if EXPERT
1565 default y 1528 default y
1566 help 1529 help
1567 sys_sysfs is an obsolete system cal 1530 sys_sysfs is an obsolete system call no longer supported in libc.
1568 Note that disabling this option is 1531 Note that disabling this option is more secure but might break
1569 compatibility with some systems. 1532 compatibility with some systems.
1570 1533
1571 If unsure say Y here. 1534 If unsure say Y here.
1572 1535
1573 config FHANDLE 1536 config FHANDLE
1574 bool "open by fhandle syscalls" if EX 1537 bool "open by fhandle syscalls" if EXPERT
1575 select EXPORTFS 1538 select EXPORTFS
1576 default y 1539 default y
1577 help 1540 help
1578 If you say Y here, a user level pro 1541 If you say Y here, a user level program will be able to map
1579 file names to handle and then later 1542 file names to handle and then later use the handle for
1580 different file system operations. T 1543 different file system operations. This is useful in implementing
1581 userspace file servers, which now t 1544 userspace file servers, which now track files using handles instead
1582 of names. The handle would remain t 1545 of names. The handle would remain the same even if file names
1583 get renamed. Enables open_by_handle 1546 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
1584 syscalls. 1547 syscalls.
1585 1548
1586 config POSIX_TIMERS 1549 config POSIX_TIMERS
1587 bool "Posix Clocks & timers" if EXPER 1550 bool "Posix Clocks & timers" if EXPERT
1588 default y 1551 default y
1589 help 1552 help
1590 This includes native support for PO 1553 This includes native support for POSIX timers to the kernel.
1591 Some embedded systems have no use f 1554 Some embedded systems have no use for them and therefore they
1592 can be configured out to reduce the 1555 can be configured out to reduce the size of the kernel image.
1593 1556
1594 When this option is disabled, the f 1557 When this option is disabled, the following syscalls won't be
1595 available: timer_create, timer_gett 1558 available: timer_create, timer_gettime: timer_getoverrun,
1596 timer_settime, timer_delete, clock_ 1559 timer_settime, timer_delete, clock_adjtime, getitimer,
1597 setitimer, alarm. Furthermore, the 1560 setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
1598 clock_getres and clock_nanosleep sy 1561 clock_getres and clock_nanosleep syscalls will be limited to
1599 CLOCK_REALTIME, CLOCK_MONOTONIC and 1562 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
1600 1563
1601 If unsure say y. 1564 If unsure say y.
1602 1565
1603 config PRINTK 1566 config PRINTK
1604 default y 1567 default y
1605 bool "Enable support for printk" if E 1568 bool "Enable support for printk" if EXPERT
1606 select IRQ_WORK 1569 select IRQ_WORK
1607 help 1570 help
1608 This option enables normal printk s 1571 This option enables normal printk support. Removing it
1609 eliminates most of the message stri 1572 eliminates most of the message strings from the kernel image
1610 and makes the kernel more or less s 1573 and makes the kernel more or less silent. As this makes it
1611 very difficult to diagnose system p 1574 very difficult to diagnose system problems, saying N here is
1612 strongly discouraged. 1575 strongly discouraged.
1613 1576
1614 config BUG 1577 config BUG
1615 bool "BUG() support" if EXPERT 1578 bool "BUG() support" if EXPERT
1616 default y 1579 default y
1617 help 1580 help
1618 Disabling this option eliminates su 1581 Disabling this option eliminates support for BUG and WARN, reducing
1619 the size of your kernel image and p 1582 the size of your kernel image and potentially quietly ignoring
1620 numerous fatal conditions. You shou 1583 numerous fatal conditions. You should only consider disabling this
1621 option for embedded systems with no 1584 option for embedded systems with no facilities for reporting errors.
1622 Just say Y. 1585 Just say Y.
1623 1586
1624 config ELF_CORE 1587 config ELF_CORE
1625 depends on COREDUMP 1588 depends on COREDUMP
1626 default y 1589 default y
1627 bool "Enable ELF core dumps" if EXPER 1590 bool "Enable ELF core dumps" if EXPERT
1628 help 1591 help
1629 Enable support for generating core 1592 Enable support for generating core dumps. Disabling saves about 4k.
1630 1593
1631 1594
1632 config PCSPKR_PLATFORM 1595 config PCSPKR_PLATFORM
1633 bool "Enable PC-Speaker support" if E 1596 bool "Enable PC-Speaker support" if EXPERT
1634 depends on HAVE_PCSPKR_PLATFORM 1597 depends on HAVE_PCSPKR_PLATFORM
1635 select I8253_LOCK 1598 select I8253_LOCK
1636 default y 1599 default y
1637 help 1600 help
1638 This option allows to disable the i 1601 This option allows to disable the internal PC-Speaker
1639 support, saving some memory. 1602 support, saving some memory.
1640 1603
1641 config BASE_SMALL !! 1604 config BASE_FULL
1642 bool "Enable smaller-sized data struc !! 1605 default y
>> 1606 bool "Enable full-sized data structures for core" if EXPERT
1643 help 1607 help
1644 Enabling this option reduces the si !! 1608 Disabling this option reduces the size of miscellaneous core
1645 kernel data structures. This saves 1609 kernel data structures. This saves memory on small machines,
1646 but may reduce performance. 1610 but may reduce performance.
1647 1611
1648 config FUTEX 1612 config FUTEX
1649 bool "Enable futex support" if EXPERT 1613 bool "Enable futex support" if EXPERT
1650 depends on !(SPARC32 && SMP) 1614 depends on !(SPARC32 && SMP)
1651 default y 1615 default y
1652 imply RT_MUTEXES 1616 imply RT_MUTEXES
1653 help 1617 help
1654 Disabling this option will cause th 1618 Disabling this option will cause the kernel to be built without
1655 support for "fast userspace mutexes 1619 support for "fast userspace mutexes". The resulting kernel may not
1656 run glibc-based applications correc 1620 run glibc-based applications correctly.
1657 1621
1658 config FUTEX_PI 1622 config FUTEX_PI
1659 bool 1623 bool
1660 depends on FUTEX && RT_MUTEXES 1624 depends on FUTEX && RT_MUTEXES
1661 default y 1625 default y
1662 1626
1663 config EPOLL 1627 config EPOLL
1664 bool "Enable eventpoll support" if EX 1628 bool "Enable eventpoll support" if EXPERT
1665 default y 1629 default y
1666 help 1630 help
1667 Disabling this option will cause th 1631 Disabling this option will cause the kernel to be built without
1668 support for epoll family of system 1632 support for epoll family of system calls.
1669 1633
1670 config SIGNALFD 1634 config SIGNALFD
1671 bool "Enable signalfd() system call" 1635 bool "Enable signalfd() system call" if EXPERT
1672 default y 1636 default y
1673 help 1637 help
1674 Enable the signalfd() system call t 1638 Enable the signalfd() system call that allows to receive signals
1675 on a file descriptor. 1639 on a file descriptor.
1676 1640
1677 If unsure, say Y. 1641 If unsure, say Y.
1678 1642
1679 config TIMERFD 1643 config TIMERFD
1680 bool "Enable timerfd() system call" i 1644 bool "Enable timerfd() system call" if EXPERT
1681 default y 1645 default y
1682 help 1646 help
1683 Enable the timerfd() system call th 1647 Enable the timerfd() system call that allows to receive timer
1684 events on a file descriptor. 1648 events on a file descriptor.
1685 1649
1686 If unsure, say Y. 1650 If unsure, say Y.
1687 1651
1688 config EVENTFD 1652 config EVENTFD
1689 bool "Enable eventfd() system call" i 1653 bool "Enable eventfd() system call" if EXPERT
1690 default y 1654 default y
1691 help 1655 help
1692 Enable the eventfd() system call th 1656 Enable the eventfd() system call that allows to receive both
1693 kernel notification (ie. KAIO) or u 1657 kernel notification (ie. KAIO) or userspace notifications.
1694 1658
1695 If unsure, say Y. 1659 If unsure, say Y.
1696 1660
1697 config SHMEM 1661 config SHMEM
1698 bool "Use full shmem filesystem" if E 1662 bool "Use full shmem filesystem" if EXPERT
1699 default y 1663 default y
1700 depends on MMU 1664 depends on MMU
1701 help 1665 help
1702 The shmem is an internal filesystem 1666 The shmem is an internal filesystem used to manage shared memory.
1703 It is backed by swap and manages re 1667 It is backed by swap and manages resource limits. It is also exported
1704 to userspace as tmpfs if TMPFS is e 1668 to userspace as tmpfs if TMPFS is enabled. Disabling this
1705 option replaces shmem and tmpfs wit 1669 option replaces shmem and tmpfs with the much simpler ramfs code,
1706 which may be appropriate on small s 1670 which may be appropriate on small systems without swap.
1707 1671
1708 config AIO 1672 config AIO
1709 bool "Enable AIO support" if EXPERT 1673 bool "Enable AIO support" if EXPERT
1710 default y 1674 default y
1711 help 1675 help
1712 This option enables POSIX asynchron 1676 This option enables POSIX asynchronous I/O which may by used
1713 by some high performance threaded a 1677 by some high performance threaded applications. Disabling
1714 this option saves about 7k. 1678 this option saves about 7k.
1715 1679
1716 config IO_URING 1680 config IO_URING
1717 bool "Enable IO uring support" if EXP 1681 bool "Enable IO uring support" if EXPERT
1718 select IO_WQ 1682 select IO_WQ
1719 default y 1683 default y
1720 help 1684 help
1721 This option enables support for the 1685 This option enables support for the io_uring interface, enabling
1722 applications to submit and complete 1686 applications to submit and complete IO through submission and
1723 completion rings that are shared be 1687 completion rings that are shared between the kernel and application.
1724 1688
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 1689 config ADVISE_SYSCALLS
1739 bool "Enable madvise/fadvise syscalls 1690 bool "Enable madvise/fadvise syscalls" if EXPERT
1740 default y 1691 default y
1741 help 1692 help
1742 This option enables the madvise and 1693 This option enables the madvise and fadvise syscalls, used by
1743 applications to advise the kernel a 1694 applications to advise the kernel about their future memory or file
1744 usage, improving performance. If bu 1695 usage, improving performance. If building an embedded system where no
1745 applications use these syscalls, yo 1696 applications use these syscalls, you can disable this option to save
1746 space. 1697 space.
1747 1698
1748 config MEMBARRIER 1699 config MEMBARRIER
1749 bool "Enable membarrier() system call 1700 bool "Enable membarrier() system call" if EXPERT
1750 default y 1701 default y
1751 help 1702 help
1752 Enable the membarrier() system call 1703 Enable the membarrier() system call that allows issuing memory
1753 barriers across all running threads 1704 barriers across all running threads, which can be used to distribute
1754 the cost of user-space memory barri 1705 the cost of user-space memory barriers asymmetrically by transforming
1755 pairs of memory barriers into pairs 1706 pairs of memory barriers into pairs consisting of membarrier() and a
1756 compiler barrier. 1707 compiler barrier.
1757 1708
1758 If unsure, say Y. 1709 If unsure, say Y.
1759 1710
1760 config KCMP <<
1761 bool "Enable kcmp() system call" if E <<
1762 help <<
1763 Enable the kernel resource comparis <<
1764 user-space with the ability to comp <<
1765 share a common resource, such as a <<
1766 memory space. <<
1767 <<
1768 If unsure, say N. <<
1769 <<
1770 config RSEQ <<
1771 bool "Enable rseq() system call" if E <<
1772 default y <<
1773 depends on HAVE_RSEQ <<
1774 select MEMBARRIER <<
1775 help <<
1776 Enable the restartable sequences sy <<
1777 user-space cache for the current CP <<
1778 speeds up getting the current CPU n <<
1779 as well as an ABI to speed up user- <<
1780 per-CPU data. <<
1781 <<
1782 If unsure, say Y. <<
1783 <<
1784 config DEBUG_RSEQ <<
1785 default n <<
1786 bool "Enable debugging of rseq() syst <<
1787 depends on RSEQ && DEBUG_KERNEL <<
1788 help <<
1789 Enable extra debugging checks for t <<
1790 <<
1791 If unsure, say N. <<
1792 <<
1793 config CACHESTAT_SYSCALL <<
1794 bool "Enable cachestat() system call" <<
1795 default y <<
1796 help <<
1797 Enable the cachestat system call, w <<
1798 statistics of a file (number of cac <<
1799 pages marked for writeback, (recent <<
1800 <<
1801 If unsure say Y here. <<
1802 <<
1803 config PC104 <<
1804 bool "PC/104 support" if EXPERT <<
1805 help <<
1806 Expose PC/104 form factor device dr <<
1807 selection and configuration. Enable <<
1808 machine has a PC/104 bus. <<
1809 <<
1810 config KALLSYMS 1711 config KALLSYMS
1811 bool "Load all symbols for debugging/ 1712 bool "Load all symbols for debugging/ksymoops" if EXPERT
1812 default y 1713 default y
1813 help 1714 help
1814 Say Y here to let the kernel print 1715 Say Y here to let the kernel print out symbolic crash information and
1815 symbolic stack backtraces. This inc 1716 symbolic stack backtraces. This increases the size of the kernel
1816 somewhat, as all symbols have to be 1717 somewhat, as all symbols have to be loaded into the kernel image.
1817 1718
1818 config KALLSYMS_SELFTEST <<
1819 bool "Test the basic functions and pe <<
1820 depends on KALLSYMS <<
1821 default n <<
1822 help <<
1823 Test the basic functions and perfor <<
1824 kallsyms_lookup_name. It also calcu <<
1825 kallsyms compression algorithm for <<
1826 <<
1827 Start self-test automatically after <<
1828 "dmesg | grep kallsyms_selftest" to <<
1829 displayed in the last line, indicat <<
1830 <<
1831 config KALLSYMS_ALL 1719 config KALLSYMS_ALL
1832 bool "Include all symbols in kallsyms 1720 bool "Include all symbols in kallsyms"
1833 depends on DEBUG_KERNEL && KALLSYMS 1721 depends on DEBUG_KERNEL && KALLSYMS
1834 help 1722 help
1835 Normally kallsyms only contains the 1723 Normally kallsyms only contains the symbols of functions for nicer
1836 OOPS messages and backtraces (i.e., 1724 OOPS messages and backtraces (i.e., symbols from the text and inittext
1837 sections). This is sufficient for m 1725 sections). This is sufficient for most cases. And only if you want to
1838 enable kernel live patching, or oth 1726 enable kernel live patching, or other less common use cases (e.g.,
1839 when a debugger is used) all symbol 1727 when a debugger is used) all symbols are required (i.e., names of
1840 variables from the data sections, e 1728 variables from the data sections, etc).
1841 1729
1842 This option makes sure that all sym 1730 This option makes sure that all symbols are loaded into the kernel
1843 image (i.e., symbols from all secti 1731 image (i.e., symbols from all sections) in cost of increased kernel
1844 size (depending on the kernel confi 1732 size (depending on the kernel configuration, it may be 300KiB or
1845 something like this). 1733 something like this).
1846 1734
1847 Say N unless you really need all sy 1735 Say N unless you really need all symbols, or kernel live patching.
1848 1736
1849 config KALLSYMS_ABSOLUTE_PERCPU 1737 config KALLSYMS_ABSOLUTE_PERCPU
1850 bool 1738 bool
1851 depends on KALLSYMS 1739 depends on KALLSYMS
1852 default X86_64 && SMP 1740 default X86_64 && SMP
1853 1741
>> 1742 config KALLSYMS_BASE_RELATIVE
>> 1743 bool
>> 1744 depends on KALLSYMS
>> 1745 default !IA64
>> 1746 help
>> 1747 Instead of emitting them as absolute values in the native word size,
>> 1748 emit the symbol references in the kallsyms table as 32-bit entries,
>> 1749 each containing a relative value in the range [base, base + U32_MAX]
>> 1750 or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either
>> 1751 an absolute value in the range [0, S32_MAX] or a relative value in the
>> 1752 range [base, base + S32_MAX], where base is the lowest relative symbol
>> 1753 address encountered in the image.
>> 1754
>> 1755 On 64-bit builds, this reduces the size of the address table by 50%,
>> 1756 but more importantly, it results in entries whose values are build
>> 1757 time constants, and no relocation pass is required at runtime to fix
>> 1758 up the entries based on the runtime load address of the kernel.
>> 1759
1854 # end of the "standard kernel features (exper 1760 # end of the "standard kernel features (expert users)" menu
1855 1761
>> 1762 # syscall, maps, verifier
>> 1763
1856 config ARCH_HAS_MEMBARRIER_CALLBACKS 1764 config ARCH_HAS_MEMBARRIER_CALLBACKS
1857 bool 1765 bool
1858 1766
1859 config ARCH_HAS_MEMBARRIER_SYNC_CORE 1767 config ARCH_HAS_MEMBARRIER_SYNC_CORE
1860 bool 1768 bool
1861 1769
>> 1770 config KCMP
>> 1771 bool "Enable kcmp() system call" if EXPERT
>> 1772 help
>> 1773 Enable the kernel resource comparison system call. It provides
>> 1774 user-space with the ability to compare two processes to see if they
>> 1775 share a common resource, such as a file descriptor or even virtual
>> 1776 memory space.
>> 1777
>> 1778 If unsure, say N.
>> 1779
>> 1780 config RSEQ
>> 1781 bool "Enable rseq() system call" if EXPERT
>> 1782 default y
>> 1783 depends on HAVE_RSEQ
>> 1784 select MEMBARRIER
>> 1785 help
>> 1786 Enable the restartable sequences system call. It provides a
>> 1787 user-space cache for the current CPU number value, which
>> 1788 speeds up getting the current CPU number from user-space,
>> 1789 as well as an ABI to speed up user-space operations on
>> 1790 per-CPU data.
>> 1791
>> 1792 If unsure, say Y.
>> 1793
>> 1794 config DEBUG_RSEQ
>> 1795 default n
>> 1796 bool "Enabled debugging of rseq() system call" if EXPERT
>> 1797 depends on RSEQ && DEBUG_KERNEL
>> 1798 help
>> 1799 Enable extra debugging checks for the rseq system call.
>> 1800
>> 1801 If unsure, say N.
>> 1802
>> 1803 config EMBEDDED
>> 1804 bool "Embedded system"
>> 1805 select EXPERT
>> 1806 help
>> 1807 This option should be enabled if compiling the kernel for
>> 1808 an embedded system so certain expert options are available
>> 1809 for configuration.
>> 1810
1862 config HAVE_PERF_EVENTS 1811 config HAVE_PERF_EVENTS
1863 bool 1812 bool
1864 help 1813 help
1865 See tools/perf/design.txt for detai 1814 See tools/perf/design.txt for details.
1866 1815
1867 config GUEST_PERF_EVENTS 1816 config GUEST_PERF_EVENTS
1868 bool 1817 bool
1869 depends on HAVE_PERF_EVENTS 1818 depends on HAVE_PERF_EVENTS
1870 1819
1871 config PERF_USE_VMALLOC 1820 config PERF_USE_VMALLOC
1872 bool 1821 bool
1873 help 1822 help
1874 See tools/perf/design.txt for detai 1823 See tools/perf/design.txt for details
1875 1824
>> 1825 config PC104
>> 1826 bool "PC/104 support" if EXPERT
>> 1827 help
>> 1828 Expose PC/104 form factor device drivers and options available for
>> 1829 selection and configuration. Enable this option if your target
>> 1830 machine has a PC/104 bus.
>> 1831
1876 menu "Kernel Performance Events And Counters" 1832 menu "Kernel Performance Events And Counters"
1877 1833
1878 config PERF_EVENTS 1834 config PERF_EVENTS
1879 bool "Kernel performance events and c 1835 bool "Kernel performance events and counters"
1880 default y if PROFILING 1836 default y if PROFILING
1881 depends on HAVE_PERF_EVENTS 1837 depends on HAVE_PERF_EVENTS
1882 select IRQ_WORK 1838 select IRQ_WORK
>> 1839 select SRCU
1883 help 1840 help
1884 Enable kernel support for various p 1841 Enable kernel support for various performance events provided
1885 by software and hardware. 1842 by software and hardware.
1886 1843
1887 Software events are supported eithe 1844 Software events are supported either built-in or via the
1888 use of generic tracepoints. 1845 use of generic tracepoints.
1889 1846
1890 Most modern CPUs support performanc 1847 Most modern CPUs support performance events via performance
1891 counter registers. These registers 1848 counter registers. These registers count the number of certain
1892 types of hw events: such as instruc 1849 types of hw events: such as instructions executed, cachemisses
1893 suffered, or branches mis-predicted 1850 suffered, or branches mis-predicted - without slowing down the
1894 kernel or applications. These regis 1851 kernel or applications. These registers can also trigger interrupts
1895 when a threshold number of events h 1852 when a threshold number of events have passed - and can thus be
1896 used to profile the code that runs 1853 used to profile the code that runs on that CPU.
1897 1854
1898 The Linux Performance Event subsyst 1855 The Linux Performance Event subsystem provides an abstraction of
1899 these software and hardware event c 1856 these software and hardware event capabilities, available via a
1900 system call and used by the "perf" 1857 system call and used by the "perf" utility in tools/perf/. It
1901 provides per task and per CPU count 1858 provides per task and per CPU counters, and it provides event
1902 capabilities on top of those. 1859 capabilities on top of those.
1903 1860
1904 Say Y if unsure. 1861 Say Y if unsure.
1905 1862
1906 config DEBUG_PERF_USE_VMALLOC 1863 config DEBUG_PERF_USE_VMALLOC
1907 default n 1864 default n
1908 bool "Debug: use vmalloc to back perf 1865 bool "Debug: use vmalloc to back perf mmap() buffers"
1909 depends on PERF_EVENTS && DEBUG_KERNE 1866 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
1910 select PERF_USE_VMALLOC 1867 select PERF_USE_VMALLOC
1911 help 1868 help
1912 Use vmalloc memory to back perf mma 1869 Use vmalloc memory to back perf mmap() buffers.
1913 1870
1914 Mostly useful for debugging the vma 1871 Mostly useful for debugging the vmalloc code on platforms
1915 that don't require it. 1872 that don't require it.
1916 1873
1917 Say N if unsure. 1874 Say N if unsure.
1918 1875
1919 endmenu 1876 endmenu
1920 1877
1921 config SYSTEM_DATA_VERIFICATION 1878 config SYSTEM_DATA_VERIFICATION
1922 def_bool n 1879 def_bool n
1923 select SYSTEM_TRUSTED_KEYRING 1880 select SYSTEM_TRUSTED_KEYRING
1924 select KEYS 1881 select KEYS
1925 select CRYPTO 1882 select CRYPTO
1926 select CRYPTO_RSA 1883 select CRYPTO_RSA
1927 select ASYMMETRIC_KEY_TYPE 1884 select ASYMMETRIC_KEY_TYPE
1928 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 1885 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1929 select ASN1 1886 select ASN1
1930 select OID_REGISTRY 1887 select OID_REGISTRY
1931 select X509_CERTIFICATE_PARSER 1888 select X509_CERTIFICATE_PARSER
1932 select PKCS7_MESSAGE_PARSER 1889 select PKCS7_MESSAGE_PARSER
1933 help 1890 help
1934 Provide PKCS#7 message verification 1891 Provide PKCS#7 message verification using the contents of the system
1935 trusted keyring to provide public k 1892 trusted keyring to provide public keys. This then can be used for
1936 module verification, kexec image ve 1893 module verification, kexec image verification and firmware blob
1937 verification. 1894 verification.
1938 1895
1939 config PROFILING 1896 config PROFILING
1940 bool "Profiling support" 1897 bool "Profiling support"
1941 help 1898 help
1942 Say Y here to enable the extended p 1899 Say Y here to enable the extended profiling support mechanisms used
1943 by profilers. 1900 by profilers.
1944 1901
1945 config RUST <<
1946 bool "Rust support" <<
1947 depends on HAVE_RUST <<
1948 depends on RUST_IS_AVAILABLE <<
1949 depends on !MODVERSIONS <<
1950 depends on !GCC_PLUGIN_RANDSTRUCT <<
1951 depends on !RANDSTRUCT <<
1952 depends on !DEBUG_INFO_BTF || PAHOLE_ <<
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 <<
1959 Enables Rust support in the kernel. <<
1960 <<
1961 This allows other Rust-related opti <<
1962 to be selected. <<
1963 <<
1964 It is also required to be able to l <<
1965 written in Rust. <<
1966 <<
1967 See Documentation/rust/ for more in <<
1968 <<
1969 If unsure, say N. <<
1970 <<
1971 config RUSTC_VERSION_TEXT <<
1972 string <<
1973 depends on RUST <<
1974 default "$(RUSTC_VERSION_TEXT)" <<
1975 help <<
1976 See `CC_VERSION_TEXT`. <<
1977 <<
1978 config BINDGEN_VERSION_TEXT <<
1979 string <<
1980 depends on RUST <<
1981 # The dummy parameter `workaround-for <<
1982 # (https://github.com/rust-lang/rust- <<
1983 # the minimum version is upgraded pas <<
1984 default "$(shell,$(BINDGEN) --version <<
1985 <<
1986 # 1902 #
1987 # Place an empty function call at each tracep 1903 # Place an empty function call at each tracepoint site. Can be
1988 # dynamically changed for a probe function. 1904 # dynamically changed for a probe function.
1989 # 1905 #
1990 config TRACEPOINTS 1906 config TRACEPOINTS
1991 bool 1907 bool
1992 1908
1993 source "kernel/Kconfig.kexec" <<
1994 <<
1995 endmenu # General setup 1909 endmenu # General setup
1996 1910
1997 source "arch/Kconfig" 1911 source "arch/Kconfig"
1998 1912
1999 config RT_MUTEXES 1913 config RT_MUTEXES
2000 bool 1914 bool
2001 default y if PREEMPT_RT 1915 default y if PREEMPT_RT
2002 1916
>> 1917 config BASE_SMALL
>> 1918 int
>> 1919 default 0 if BASE_FULL
>> 1920 default 1 if !BASE_FULL
>> 1921
2003 config MODULE_SIG_FORMAT 1922 config MODULE_SIG_FORMAT
2004 def_bool n 1923 def_bool n
2005 select SYSTEM_DATA_VERIFICATION 1924 select SYSTEM_DATA_VERIFICATION
2006 1925
2007 source "kernel/module/Kconfig" 1926 source "kernel/module/Kconfig"
2008 1927
2009 config INIT_ALL_POSSIBLE 1928 config INIT_ALL_POSSIBLE
2010 bool 1929 bool
2011 help 1930 help
2012 Back when each arch used to define 1931 Back when each arch used to define their own cpu_online_mask and
2013 cpu_possible_mask, some of them cho 1932 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
2014 with all 1s, and others with all 0s 1933 with all 1s, and others with all 0s. When they were centralised,
2015 it was better to provide this optio 1934 it was better to provide this option than to break all the archs
2016 and have several arch maintainers p 1935 and have several arch maintainers pursuing me down dark alleys.
2017 1936
2018 source "block/Kconfig" 1937 source "block/Kconfig"
2019 1938
2020 config PREEMPT_NOTIFIERS 1939 config PREEMPT_NOTIFIERS
2021 bool 1940 bool
2022 1941
2023 config PADATA 1942 config PADATA
2024 depends on SMP 1943 depends on SMP
2025 bool 1944 bool
2026 1945
2027 config ASN1 1946 config ASN1
2028 tristate 1947 tristate
2029 help 1948 help
2030 Build a simple ASN.1 grammar compil 1949 Build a simple ASN.1 grammar compiler that produces a bytecode output
2031 that can be interpreted by the ASN. 1950 that can be interpreted by the ASN.1 stream decoder and used to
2032 inform it as to what tags are to be 1951 inform it as to what tags are to be expected in a stream and what
2033 functions to call on what tags. 1952 functions to call on what tags.
2034 1953
2035 source "kernel/Kconfig.locks" 1954 source "kernel/Kconfig.locks"
2036 1955
2037 config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 1956 config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
2038 bool <<
2039 <<
2040 config ARCH_HAS_PREPARE_SYNC_CORE_CMD <<
2041 bool 1957 bool
2042 1958
2043 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 1959 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
2044 bool 1960 bool
2045 1961
2046 # It may be useful for an architecture to ove 1962 # It may be useful for an architecture to override the definitions of the
2047 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() ma 1963 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h>
2048 # and the COMPAT_ variants in <linux/compat.h 1964 # and the COMPAT_ variants in <linux/compat.h>, in particular to use a
2049 # different calling convention for syscalls. 1965 # different calling convention for syscalls. They can also override the
2050 # macros for not-implemented syscalls in kern 1966 # macros for not-implemented syscalls in kernel/sys_ni.c and
2051 # kernel/time/posix-stubs.c. All these overri 1967 # kernel/time/posix-stubs.c. All these overrides need to be available in
2052 # <asm/syscall_wrapper.h>. 1968 # <asm/syscall_wrapper.h>.
2053 config ARCH_HAS_SYSCALL_WRAPPER 1969 config ARCH_HAS_SYSCALL_WRAPPER
2054 def_bool n 1970 def_bool n
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