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) $(m64-flag)) if 64BIT
88 default $(success,$(srctree)/scripts/c !! 66 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(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) $(m64-flag) -static) if 64BIT
93 default $(success,$(srctree)/scripts/c !! 71 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m32-flag) -static)
94 72
95 # Fixed in GCC 14, 13.3, 12.4 and 11.5 !! 73 config CC_HAS_ASM_GOTO
96 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id !! 74 def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC))
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 75
104 config CC_HAS_ASM_GOTO_OUTPUT 76 config CC_HAS_ASM_GOTO_OUTPUT
105 def_bool y !! 77 depends on CC_HAS_ASM_GOTO
106 depends on !GCC_ASM_GOTO_OUTPUT_BROKEN !! 78 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)
107 depends on $(success,echo 'int foo(int <<
108 <<
109 config CC_HAS_ASM_GOTO_TIED_OUTPUT <<
110 depends on CC_HAS_ASM_GOTO_OUTPUT <<
111 # Detect buggy gcc and clang, fixed in <<
112 def_bool $(success,echo 'int foo(int * <<
113 79
114 config TOOLS_SUPPORT_RELR 80 config TOOLS_SUPPORT_RELR
115 def_bool $(success,env "CC=$(CC)" "LD= 81 def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh)
116 82
117 config CC_HAS_ASM_INLINE 83 config CC_HAS_ASM_INLINE
118 def_bool $(success,echo 'void foo(void 84 def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null)
119 85
120 config CC_HAS_NO_PROFILE_FN_ATTR <<
121 def_bool $(success,echo '__attribute__ <<
122 <<
123 config PAHOLE_VERSION <<
124 int <<
125 default $(shell,$(srctree)/scripts/pah <<
126 <<
127 config CONSTRUCTORS 86 config CONSTRUCTORS
128 bool 87 bool
129 88
130 config IRQ_WORK 89 config IRQ_WORK
131 def_bool y if SMP !! 90 bool
132 91
133 config BUILDTIME_TABLE_SORT 92 config BUILDTIME_TABLE_SORT
134 bool 93 bool
135 94
136 config THREAD_INFO_IN_TASK 95 config THREAD_INFO_IN_TASK
137 bool 96 bool
138 help 97 help
139 Select this to move thread_info off 98 Select this to move thread_info off the stack into task_struct. To
140 make this work, an arch will need to 99 make this work, an arch will need to remove all thread_info fields
141 except flags and fix any runtime bug 100 except flags and fix any runtime bugs.
142 101
143 One subtle change that will be neede 102 One subtle change that will be needed is to use try_get_task_stack()
144 and put_task_stack() in save_thread_ 103 and put_task_stack() in save_thread_stack_tsk() and get_wchan().
145 104
146 menu "General setup" 105 menu "General setup"
147 106
148 config BROKEN 107 config BROKEN
149 bool 108 bool
150 109
151 config BROKEN_ON_SMP 110 config BROKEN_ON_SMP
152 bool 111 bool
153 depends on BROKEN || !SMP 112 depends on BROKEN || !SMP
154 default y 113 default y
155 114
156 config INIT_ENV_ARG_LIMIT 115 config INIT_ENV_ARG_LIMIT
157 int 116 int
158 default 32 if !UML 117 default 32 if !UML
159 default 128 if UML 118 default 128 if UML
160 help 119 help
161 Maximum of each of the number of arg 120 Maximum of each of the number of arguments and environment
162 variables passed to init from the ke 121 variables passed to init from the kernel command line.
163 122
164 config COMPILE_TEST 123 config COMPILE_TEST
165 bool "Compile also drivers which will 124 bool "Compile also drivers which will not load"
166 depends on HAS_IOMEM 125 depends on HAS_IOMEM
167 help 126 help
168 Some drivers can be compiled on a di 127 Some drivers can be compiled on a different platform than they are
169 intended to be run on. Despite they 128 intended to be run on. Despite they cannot be loaded there (or even
170 when they load they cannot be used d 129 when they load they cannot be used due to missing HW support),
171 developers still, opposing to distri 130 developers still, opposing to distributors, might want to build such
172 drivers to compile-test them. 131 drivers to compile-test them.
173 132
174 If you are a developer and want to b 133 If you are a developer and want to build everything available, say Y
175 here. If you are a user/distributor, 134 here. If you are a user/distributor, say N here to exclude useless
176 drivers to be distributed. 135 drivers to be distributed.
177 136
178 config WERROR <<
179 bool "Compile the kernel with warnings <<
180 default COMPILE_TEST <<
181 help <<
182 A kernel build should not cause any <<
183 enables the '-Werror' (for C) and '- <<
184 to enforce that rule by default. Cer <<
185 such as the linker may be upgraded t <<
186 well. <<
187 <<
188 However, if you have a new (or very <<
189 and unusual warnings, or you have so <<
190 you may need to disable this config <<
191 successfully build the kernel. <<
192 <<
193 If in doubt, say Y. <<
194 <<
195 config UAPI_HEADER_TEST 137 config UAPI_HEADER_TEST
196 bool "Compile test UAPI headers" 138 bool "Compile test UAPI headers"
197 depends on HEADERS_INSTALL && CC_CAN_L 139 depends on HEADERS_INSTALL && CC_CAN_LINK
198 help 140 help
199 Compile test headers exported to use 141 Compile test headers exported to user-space to ensure they are
200 self-contained, i.e. compilable as s 142 self-contained, i.e. compilable as standalone units.
201 143
202 If you are a developer or tester and 144 If you are a developer or tester and want to ensure the exported
203 headers are self-contained, say Y he 145 headers are self-contained, say Y here. Otherwise, choose N.
204 146
205 config LOCALVERSION 147 config LOCALVERSION
206 string "Local version - append to kern 148 string "Local version - append to kernel release"
207 help 149 help
208 Append an extra string to the end of 150 Append an extra string to the end of your kernel version.
209 This will show up when you type unam 151 This will show up when you type uname, for example.
210 The string you set here will be appe 152 The string you set here will be appended after the contents of
211 any files with a filename matching l 153 any files with a filename matching localversion* in your
212 object and source tree, in that orde 154 object and source tree, in that order. Your total string can
213 be a maximum of 64 characters. 155 be a maximum of 64 characters.
214 156
215 config LOCALVERSION_AUTO 157 config LOCALVERSION_AUTO
216 bool "Automatically append version inf 158 bool "Automatically append version information to the version string"
217 default y 159 default y
218 depends on !COMPILE_TEST 160 depends on !COMPILE_TEST
219 help 161 help
220 This will try to automatically deter 162 This will try to automatically determine if the current tree is a
221 release tree by looking for git tags 163 release tree by looking for git tags that belong to the current
222 top of tree revision. 164 top of tree revision.
223 165
224 A string of the format -gxxxxxxxx wi 166 A string of the format -gxxxxxxxx will be added to the localversion
225 if a git-based tree is found. The s 167 if a git-based tree is found. The string generated by this will be
226 appended after any matching localver 168 appended after any matching localversion* files, and after the value
227 set in CONFIG_LOCALVERSION. 169 set in CONFIG_LOCALVERSION.
228 170
229 (The actual string used here is the !! 171 (The actual string used here is the first eight characters produced
230 by running the command: 172 by running the command:
231 173
232 $ git rev-parse --verify HEAD 174 $ git rev-parse --verify HEAD
233 175
234 which is done within the script "scr 176 which is done within the script "scripts/setlocalversion".)
235 177
236 config BUILD_SALT 178 config BUILD_SALT
237 string "Build ID Salt" 179 string "Build ID Salt"
238 default "" 180 default ""
239 help 181 help
240 The build ID is used to link binarie 182 The build ID is used to link binaries and their debug info. Setting
241 this option will use the value in th 183 this option will use the value in the calculation of the build id.
242 This is mostly useful for distributi 184 This is mostly useful for distributions which want to ensure the
243 build is unique between builds. It's 185 build is unique between builds. It's safe to leave the default.
244 186
245 config HAVE_KERNEL_GZIP 187 config HAVE_KERNEL_GZIP
246 bool 188 bool
247 189
248 config HAVE_KERNEL_BZIP2 190 config HAVE_KERNEL_BZIP2
249 bool 191 bool
250 192
251 config HAVE_KERNEL_LZMA 193 config HAVE_KERNEL_LZMA
252 bool 194 bool
253 195
254 config HAVE_KERNEL_XZ 196 config HAVE_KERNEL_XZ
255 bool 197 bool
256 198
257 config HAVE_KERNEL_LZO 199 config HAVE_KERNEL_LZO
258 bool 200 bool
259 201
260 config HAVE_KERNEL_LZ4 202 config HAVE_KERNEL_LZ4
261 bool 203 bool
262 204
263 config HAVE_KERNEL_ZSTD 205 config HAVE_KERNEL_ZSTD
264 bool 206 bool
265 207
266 config HAVE_KERNEL_UNCOMPRESSED 208 config HAVE_KERNEL_UNCOMPRESSED
267 bool 209 bool
268 210
269 choice 211 choice
270 prompt "Kernel compression mode" 212 prompt "Kernel compression mode"
271 default KERNEL_GZIP 213 default KERNEL_GZIP
272 depends on HAVE_KERNEL_GZIP || HAVE_KE 214 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 215 help
274 The linux kernel is a kind of self-e 216 The linux kernel is a kind of self-extracting executable.
275 Several compression algorithms are a 217 Several compression algorithms are available, which differ
276 in efficiency, compression and decom 218 in efficiency, compression and decompression speed.
277 Compression speed is only relevant w 219 Compression speed is only relevant when building a kernel.
278 Decompression speed is relevant at e 220 Decompression speed is relevant at each boot.
279 221
280 If you have any problems with bzip2 222 If you have any problems with bzip2 or lzma compressed
281 kernels, mail me (Alain Knaff) <alain 223 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
282 version of this functionality (bzip2 224 version of this functionality (bzip2 only), for 2.4, was
283 supplied by Christian Ludwig) 225 supplied by Christian Ludwig)
284 226
285 High compression options are mostly 227 High compression options are mostly useful for users, who
286 are low on disk space (embedded syst 228 are low on disk space (embedded systems), but for whom ram
287 size matters less. 229 size matters less.
288 230
289 If in doubt, select 'gzip' 231 If in doubt, select 'gzip'
290 232
291 config KERNEL_GZIP 233 config KERNEL_GZIP
292 bool "Gzip" 234 bool "Gzip"
293 depends on HAVE_KERNEL_GZIP 235 depends on HAVE_KERNEL_GZIP
294 help 236 help
295 The old and tried gzip compression. 237 The old and tried gzip compression. It provides a good balance
296 between compression ratio and decomp 238 between compression ratio and decompression speed.
297 239
298 config KERNEL_BZIP2 240 config KERNEL_BZIP2
299 bool "Bzip2" 241 bool "Bzip2"
300 depends on HAVE_KERNEL_BZIP2 242 depends on HAVE_KERNEL_BZIP2
301 help 243 help
302 Its compression ratio and speed is i 244 Its compression ratio and speed is intermediate.
303 Decompression speed is slowest among 245 Decompression speed is slowest among the choices. The kernel
304 size is about 10% smaller with bzip2 246 size is about 10% smaller with bzip2, in comparison to gzip.
305 Bzip2 uses a large amount of memory. 247 Bzip2 uses a large amount of memory. For modern kernels you
306 will need at least 8MB RAM or more f 248 will need at least 8MB RAM or more for booting.
307 249
308 config KERNEL_LZMA 250 config KERNEL_LZMA
309 bool "LZMA" 251 bool "LZMA"
310 depends on HAVE_KERNEL_LZMA 252 depends on HAVE_KERNEL_LZMA
311 help 253 help
312 This compression algorithm's ratio i 254 This compression algorithm's ratio is best. Decompression speed
313 is between gzip and bzip2. Compress 255 is between gzip and bzip2. Compression is slowest.
314 The kernel size is about 33% smaller 256 The kernel size is about 33% smaller with LZMA in comparison to gzip.
315 257
316 config KERNEL_XZ 258 config KERNEL_XZ
317 bool "XZ" 259 bool "XZ"
318 depends on HAVE_KERNEL_XZ 260 depends on HAVE_KERNEL_XZ
319 help 261 help
320 XZ uses the LZMA2 algorithm and inst 262 XZ uses the LZMA2 algorithm and instruction set specific
321 BCJ filters which can improve compre 263 BCJ filters which can improve compression ratio of executable
322 code. The size of the kernel is abou 264 code. The size of the kernel is about 30% smaller with XZ in
323 comparison to gzip. On architectures 265 comparison to gzip. On architectures for which there is a BCJ
324 filter (i386, x86_64, ARM, ARM64, RI !! 266 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
325 and SPARC), XZ will create a few per !! 267 will create a few percent smaller kernel than plain LZMA.
326 plain LZMA. <<
327 268
328 The speed is about the same as with 269 The speed is about the same as with LZMA: The decompression
329 speed of XZ is better than that of b 270 speed of XZ is better than that of bzip2 but worse than gzip
330 and LZO. Compression is slow. 271 and LZO. Compression is slow.
331 272
332 config KERNEL_LZO 273 config KERNEL_LZO
333 bool "LZO" 274 bool "LZO"
334 depends on HAVE_KERNEL_LZO 275 depends on HAVE_KERNEL_LZO
335 help 276 help
336 Its compression ratio is the poorest 277 Its compression ratio is the poorest among the choices. The kernel
337 size is about 10% bigger than gzip; 278 size is about 10% bigger than gzip; however its speed
338 (both compression and decompression) 279 (both compression and decompression) is the fastest.
339 280
340 config KERNEL_LZ4 281 config KERNEL_LZ4
341 bool "LZ4" 282 bool "LZ4"
342 depends on HAVE_KERNEL_LZ4 283 depends on HAVE_KERNEL_LZ4
343 help 284 help
344 LZ4 is an LZ77-type compressor with 285 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
345 A preliminary version of LZ4 de/comp 286 A preliminary version of LZ4 de/compression tool is available at
346 <https://code.google.com/p/lz4/>. 287 <https://code.google.com/p/lz4/>.
347 288
348 Its compression ratio is worse than 289 Its compression ratio is worse than LZO. The size of the kernel
349 is about 8% bigger than LZO. But the 290 is about 8% bigger than LZO. But the decompression speed is
350 faster than LZO. 291 faster than LZO.
351 292
352 config KERNEL_ZSTD 293 config KERNEL_ZSTD
353 bool "ZSTD" 294 bool "ZSTD"
354 depends on HAVE_KERNEL_ZSTD 295 depends on HAVE_KERNEL_ZSTD
355 help 296 help
356 ZSTD is a compression algorithm targ 297 ZSTD is a compression algorithm targeting intermediate compression
357 with fast decompression speed. It wi 298 with fast decompression speed. It will compress better than GZIP and
358 decompress around the same speed as 299 decompress around the same speed as LZO, but slower than LZ4. You
359 will need at least 192 KB RAM or mor 300 will need at least 192 KB RAM or more for booting. The zstd command
360 line tool is required for compressio 301 line tool is required for compression.
361 302
362 config KERNEL_UNCOMPRESSED 303 config KERNEL_UNCOMPRESSED
363 bool "None" 304 bool "None"
364 depends on HAVE_KERNEL_UNCOMPRESSED 305 depends on HAVE_KERNEL_UNCOMPRESSED
365 help 306 help
366 Produce uncompressed kernel image. T 307 Produce uncompressed kernel image. This option is usually not what
367 you want. It is useful for debugging 308 you want. It is useful for debugging the kernel in slow simulation
368 environments, where decompressing an 309 environments, where decompressing and moving the kernel is awfully
369 slow. This option allows early boot 310 slow. This option allows early boot code to skip the decompressor
370 and jump right at uncompressed kerne 311 and jump right at uncompressed kernel image.
371 312
372 endchoice 313 endchoice
373 314
374 config DEFAULT_INIT 315 config DEFAULT_INIT
375 string "Default init path" 316 string "Default init path"
376 default "" 317 default ""
377 help 318 help
378 This option determines the default i 319 This option determines the default init for the system if no init=
379 option is passed on the kernel comma 320 option is passed on the kernel command line. If the requested path is
380 not present, we will still then move 321 not present, we will still then move on to attempting further
381 locations (e.g. /sbin/init, etc). If 322 locations (e.g. /sbin/init, etc). If this is empty, we will just use
382 the fallback list when init= is not 323 the fallback list when init= is not passed.
383 324
384 config DEFAULT_HOSTNAME 325 config DEFAULT_HOSTNAME
385 string "Default hostname" 326 string "Default hostname"
386 default "(none)" 327 default "(none)"
387 help 328 help
388 This option determines the default s 329 This option determines the default system hostname before userspace
389 calls sethostname(2). The kernel tra 330 calls sethostname(2). The kernel traditionally uses "(none)" here,
390 but you may wish to use a different 331 but you may wish to use a different default here to make a minimal
391 system more usable with less configu 332 system more usable with less configuration.
392 333
>> 334 #
>> 335 # For some reason microblaze and nios2 hard code SWAP=n. Hopefully we can
>> 336 # add proper SWAP support to them, in which case this can be remove.
>> 337 #
>> 338 config ARCH_NO_SWAP
>> 339 bool
>> 340
>> 341 config SWAP
>> 342 bool "Support for paging of anonymous memory (swap)"
>> 343 depends on MMU && BLOCK && !ARCH_NO_SWAP
>> 344 default y
>> 345 help
>> 346 This option allows you to choose whether you want to have support
>> 347 for so called swap devices or swap files in your kernel that are
>> 348 used to provide more virtual memory than the actual RAM present
>> 349 in your computer. If unsure say Y.
>> 350
393 config SYSVIPC 351 config SYSVIPC
394 bool "System V IPC" 352 bool "System V IPC"
395 help 353 help
396 Inter Process Communication is a sui 354 Inter Process Communication is a suite of library functions and
397 system calls which let processes (ru 355 system calls which let processes (running programs) synchronize and
398 exchange information. It is generall 356 exchange information. It is generally considered to be a good thing,
399 and some programs won't run unless y 357 and some programs won't run unless you say Y here. In particular, if
400 you want to run the DOS emulator dos 358 you want to run the DOS emulator dosemu under Linux (read the
401 DOSEMU-HOWTO, available from <http:/ 359 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
402 you'll need to say Y here. 360 you'll need to say Y here.
403 361
404 You can find documentation about IPC 362 You can find documentation about IPC with "info ipc" and also in
405 section 6.4 of the Linux Programmer' 363 section 6.4 of the Linux Programmer's Guide, available from
406 <http://www.tldp.org/guides.html>. 364 <http://www.tldp.org/guides.html>.
407 365
408 config SYSVIPC_SYSCTL 366 config SYSVIPC_SYSCTL
409 bool 367 bool
410 depends on SYSVIPC 368 depends on SYSVIPC
411 depends on SYSCTL 369 depends on SYSCTL
412 default y 370 default y
413 371
414 config SYSVIPC_COMPAT <<
415 def_bool y <<
416 depends on COMPAT && SYSVIPC <<
417 <<
418 config POSIX_MQUEUE 372 config POSIX_MQUEUE
419 bool "POSIX Message Queues" 373 bool "POSIX Message Queues"
420 depends on NET 374 depends on NET
421 help 375 help
422 POSIX variant of message queues is a 376 POSIX variant of message queues is a part of IPC. In POSIX message
423 queues every message has a priority 377 queues every message has a priority which decides about succession
424 of receiving it by a process. If you 378 of receiving it by a process. If you want to compile and run
425 programs written e.g. for Solaris wi 379 programs written e.g. for Solaris with use of its POSIX message
426 queues (functions mq_*) say Y here. 380 queues (functions mq_*) say Y here.
427 381
428 POSIX message queues are visible as 382 POSIX message queues are visible as a filesystem called 'mqueue'
429 and can be mounted somewhere if you 383 and can be mounted somewhere if you want to do filesystem
430 operations on message queues. 384 operations on message queues.
431 385
432 If unsure, say Y. 386 If unsure, say Y.
433 387
434 config POSIX_MQUEUE_SYSCTL 388 config POSIX_MQUEUE_SYSCTL
435 bool 389 bool
436 depends on POSIX_MQUEUE 390 depends on POSIX_MQUEUE
437 depends on SYSCTL 391 depends on SYSCTL
438 default y 392 default y
439 393
440 config WATCH_QUEUE 394 config WATCH_QUEUE
441 bool "General notification queue" 395 bool "General notification queue"
442 default n 396 default n
443 help 397 help
444 398
445 This is a general notification queue 399 This is a general notification queue for the kernel to pass events to
446 userspace by splicing them into pipe 400 userspace by splicing them into pipes. It can be used in conjunction
447 with watches for key/keyring change 401 with watches for key/keyring change notifications and device
448 notifications. 402 notifications.
449 403
450 See Documentation/core-api/watch_que !! 404 See Documentation/watch_queue.rst
451 405
452 config CROSS_MEMORY_ATTACH 406 config CROSS_MEMORY_ATTACH
453 bool "Enable process_vm_readv/writev s 407 bool "Enable process_vm_readv/writev syscalls"
454 depends on MMU 408 depends on MMU
455 default y 409 default y
456 help 410 help
457 Enabling this option adds the system 411 Enabling this option adds the system calls process_vm_readv and
458 process_vm_writev which allow a proc 412 process_vm_writev which allow a process with the correct privileges
459 to directly read from or write to an 413 to directly read from or write to another process' address space.
460 See the man page for more details. 414 See the man page for more details.
461 415
462 config USELIB 416 config USELIB
463 bool "uselib syscall (for libc5 and ea !! 417 bool "uselib syscall"
464 default ALPHA || M68K || SPARC !! 418 def_bool ALPHA || M68K || SPARC || X86_32 || IA32_EMULATION
465 help 419 help
466 This option enables the uselib sysca 420 This option enables the uselib syscall, a system call used in the
467 dynamic linker from libc5 and earlie 421 dynamic linker from libc5 and earlier. glibc does not use this
468 system call. If you intend to run p 422 system call. If you intend to run programs built on libc5 or
469 earlier, you may need to enable this 423 earlier, you may need to enable this syscall. Current systems
470 running glibc can safely disable thi 424 running glibc can safely disable this.
471 425
472 config AUDIT 426 config AUDIT
473 bool "Auditing support" 427 bool "Auditing support"
474 depends on NET 428 depends on NET
475 help 429 help
476 Enable auditing infrastructure that 430 Enable auditing infrastructure that can be used with another
477 kernel subsystem, such as SELinux (w 431 kernel subsystem, such as SELinux (which requires this for
478 logging of avc messages output). Sy 432 logging of avc messages output). System call auditing is included
479 on architectures which support it. 433 on architectures which support it.
480 434
481 config HAVE_ARCH_AUDITSYSCALL 435 config HAVE_ARCH_AUDITSYSCALL
482 bool 436 bool
483 437
484 config AUDITSYSCALL 438 config AUDITSYSCALL
485 def_bool y 439 def_bool y
486 depends on AUDIT && HAVE_ARCH_AUDITSYS 440 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
487 select FSNOTIFY 441 select FSNOTIFY
488 442
489 source "kernel/irq/Kconfig" 443 source "kernel/irq/Kconfig"
490 source "kernel/time/Kconfig" 444 source "kernel/time/Kconfig"
491 source "kernel/bpf/Kconfig" 445 source "kernel/bpf/Kconfig"
492 source "kernel/Kconfig.preempt" 446 source "kernel/Kconfig.preempt"
493 447
494 menu "CPU/Task time and stats accounting" 448 menu "CPU/Task time and stats accounting"
495 449
496 config VIRT_CPU_ACCOUNTING 450 config VIRT_CPU_ACCOUNTING
497 bool 451 bool
498 452
499 choice 453 choice
500 prompt "Cputime accounting" 454 prompt "Cputime accounting"
501 default TICK_CPU_ACCOUNTING !! 455 default TICK_CPU_ACCOUNTING if !PPC64
>> 456 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
502 457
503 # Kind of a stub config for the pure tick base 458 # Kind of a stub config for the pure tick based cputime accounting
504 config TICK_CPU_ACCOUNTING 459 config TICK_CPU_ACCOUNTING
505 bool "Simple tick based cputime accoun 460 bool "Simple tick based cputime accounting"
506 depends on !S390 && !NO_HZ_FULL 461 depends on !S390 && !NO_HZ_FULL
507 help 462 help
508 This is the basic tick based cputime 463 This is the basic tick based cputime accounting that maintains
509 statistics about user, system and id 464 statistics about user, system and idle time spent on per jiffies
510 granularity. 465 granularity.
511 466
512 If unsure, say Y. 467 If unsure, say Y.
513 468
514 config VIRT_CPU_ACCOUNTING_NATIVE 469 config VIRT_CPU_ACCOUNTING_NATIVE
515 bool "Deterministic task and CPU time 470 bool "Deterministic task and CPU time accounting"
516 depends on HAVE_VIRT_CPU_ACCOUNTING && 471 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
517 select VIRT_CPU_ACCOUNTING 472 select VIRT_CPU_ACCOUNTING
518 help 473 help
519 Select this option to enable more ac 474 Select this option to enable more accurate task and CPU time
520 accounting. This is done by reading 475 accounting. This is done by reading a CPU counter on each
521 kernel entry and exit and on transit 476 kernel entry and exit and on transitions within the kernel
522 between system, softirq and hardirq 477 between system, softirq and hardirq state, so there is a
523 small performance impact. In the ca 478 small performance impact. In the case of s390 or IBM POWER > 5,
524 this also enables accounting of stol 479 this also enables accounting of stolen time on logically-partitioned
525 systems. 480 systems.
526 481
527 config VIRT_CPU_ACCOUNTING_GEN 482 config VIRT_CPU_ACCOUNTING_GEN
528 bool "Full dynticks CPU time accountin 483 bool "Full dynticks CPU time accounting"
529 depends on HAVE_CONTEXT_TRACKING_USER !! 484 depends on HAVE_CONTEXT_TRACKING
530 depends on HAVE_VIRT_CPU_ACCOUNTING_GE 485 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
531 depends on GENERIC_CLOCKEVENTS 486 depends on GENERIC_CLOCKEVENTS
532 select VIRT_CPU_ACCOUNTING 487 select VIRT_CPU_ACCOUNTING
533 select CONTEXT_TRACKING_USER !! 488 select CONTEXT_TRACKING
534 help 489 help
535 Select this option to enable task an 490 Select this option to enable task and CPU time accounting on full
536 dynticks systems. This accounting is 491 dynticks systems. This accounting is implemented by watching every
537 kernel-user boundaries using the con 492 kernel-user boundaries using the context tracking subsystem.
538 The accounting is thus performed at 493 The accounting is thus performed at the expense of some significant
539 overhead. 494 overhead.
540 495
541 For now this is only useful if you a 496 For now this is only useful if you are working on the full
542 dynticks subsystem development. 497 dynticks subsystem development.
543 498
544 If unsure, say N. 499 If unsure, say N.
545 500
546 endchoice 501 endchoice
547 502
548 config IRQ_TIME_ACCOUNTING 503 config IRQ_TIME_ACCOUNTING
549 bool "Fine granularity task level IRQ 504 bool "Fine granularity task level IRQ time accounting"
550 depends on HAVE_IRQ_TIME_ACCOUNTING && 505 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
551 help 506 help
552 Select this option to enable fine gr 507 Select this option to enable fine granularity task irq time
553 accounting. This is done by reading 508 accounting. This is done by reading a timestamp on each
554 transitions between softirq and hard 509 transitions between softirq and hardirq state, so there can be a
555 small performance impact. 510 small performance impact.
556 511
557 If in doubt, say N here. 512 If in doubt, say N here.
558 513
559 config HAVE_SCHED_AVG_IRQ 514 config HAVE_SCHED_AVG_IRQ
560 def_bool y 515 def_bool y
561 depends on IRQ_TIME_ACCOUNTING || PARA 516 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING
562 depends on SMP 517 depends on SMP
563 518
564 config SCHED_HW_PRESSURE !! 519 config SCHED_THERMAL_PRESSURE
565 bool 520 bool
566 default y if ARM && ARM_CPU_TOPOLOGY 521 default y if ARM && ARM_CPU_TOPOLOGY
567 default y if ARM64 522 default y if ARM64
568 depends on SMP 523 depends on SMP
569 depends on CPU_FREQ_THERMAL 524 depends on CPU_FREQ_THERMAL
570 help 525 help
571 Select this option to enable HW pres !! 526 Select this option to enable thermal pressure accounting in the
572 scheduler. HW pressure is the value !! 527 scheduler. Thermal pressure is the value conveyed to the scheduler
573 that reflects the reduction in CPU c 528 that reflects the reduction in CPU compute capacity resulted from
574 HW throttling. HW throttling occurs !! 529 thermal throttling. Thermal throttling occurs when the performance of
575 a CPU is capped due to high operatin !! 530 a CPU is capped due to high operating temperatures.
576 531
577 If selected, the scheduler will be a 532 If selected, the scheduler will be able to balance tasks accordingly,
578 i.e. put less load on throttled CPUs 533 i.e. put less load on throttled CPUs than on non/less throttled ones.
579 534
580 This requires the architecture to im 535 This requires the architecture to implement
581 arch_update_hw_pressure() and arch_s !! 536 arch_set_thermal_pressure() and arch_scale_thermal_pressure().
582 537
583 config BSD_PROCESS_ACCT 538 config BSD_PROCESS_ACCT
584 bool "BSD Process Accounting" 539 bool "BSD Process Accounting"
585 depends on MULTIUSER 540 depends on MULTIUSER
586 help 541 help
587 If you say Y here, a user level prog 542 If you say Y here, a user level program will be able to instruct the
588 kernel (via a special system call) t 543 kernel (via a special system call) to write process accounting
589 information to a file: whenever a pr 544 information to a file: whenever a process exits, information about
590 that process will be appended to the 545 that process will be appended to the file by the kernel. The
591 information includes things such as 546 information includes things such as creation time, owning user,
592 command name, memory usage, controll 547 command name, memory usage, controlling terminal etc. (the complete
593 list is in the struct acct in <file: 548 list is in the struct acct in <file:include/linux/acct.h>). It is
594 up to the user level program to do u 549 up to the user level program to do useful things with this
595 information. This is generally a go 550 information. This is generally a good idea, so say Y.
596 551
597 config BSD_PROCESS_ACCT_V3 552 config BSD_PROCESS_ACCT_V3
598 bool "BSD Process Accounting version 3 553 bool "BSD Process Accounting version 3 file format"
599 depends on BSD_PROCESS_ACCT 554 depends on BSD_PROCESS_ACCT
600 default n 555 default n
601 help 556 help
602 If you say Y here, the process accou 557 If you say Y here, the process accounting information is written
603 in a new file format that also logs 558 in a new file format that also logs the process IDs of each
604 process and its parent. Note that th 559 process and its parent. Note that this file format is incompatible
605 with previous v0/v1/v2 file formats, 560 with previous v0/v1/v2 file formats, so you will need updated tools
606 for processing it. A preliminary ver 561 for processing it. A preliminary version of these tools is available
607 at <http://www.gnu.org/software/acct 562 at <http://www.gnu.org/software/acct/>.
608 563
609 config TASKSTATS 564 config TASKSTATS
610 bool "Export task/process statistics t 565 bool "Export task/process statistics through netlink"
611 depends on NET 566 depends on NET
612 depends on MULTIUSER 567 depends on MULTIUSER
613 default n 568 default n
614 help 569 help
615 Export selected statistics for tasks 570 Export selected statistics for tasks/processes through the
616 generic netlink interface. Unlike BS 571 generic netlink interface. Unlike BSD process accounting, the
617 statistics are available during the 572 statistics are available during the lifetime of tasks/processes as
618 responses to commands. Like BSD acco 573 responses to commands. Like BSD accounting, they are sent to user
619 space on task exit. 574 space on task exit.
620 575
621 Say N if unsure. 576 Say N if unsure.
622 577
623 config TASK_DELAY_ACCT 578 config TASK_DELAY_ACCT
624 bool "Enable per-task delay accounting 579 bool "Enable per-task delay accounting"
625 depends on TASKSTATS 580 depends on TASKSTATS
626 select SCHED_INFO 581 select SCHED_INFO
627 help 582 help
628 Collect information on time spent by 583 Collect information on time spent by a task waiting for system
629 resources like cpu, synchronous bloc 584 resources like cpu, synchronous block I/O completion and swapping
630 in pages. Such statistics can help i 585 in pages. Such statistics can help in setting a task's priorities
631 relative to other tasks for cpu, io, 586 relative to other tasks for cpu, io, rss limits etc.
632 587
633 Say N if unsure. 588 Say N if unsure.
634 589
635 config TASK_XACCT 590 config TASK_XACCT
636 bool "Enable extended accounting over 591 bool "Enable extended accounting over taskstats"
637 depends on TASKSTATS 592 depends on TASKSTATS
638 help 593 help
639 Collect extended task accounting dat 594 Collect extended task accounting data and send the data
640 to userland for processing over the 595 to userland for processing over the taskstats interface.
641 596
642 Say N if unsure. 597 Say N if unsure.
643 598
644 config TASK_IO_ACCOUNTING 599 config TASK_IO_ACCOUNTING
645 bool "Enable per-task storage I/O acco 600 bool "Enable per-task storage I/O accounting"
646 depends on TASK_XACCT 601 depends on TASK_XACCT
647 help 602 help
648 Collect information on the number of 603 Collect information on the number of bytes of storage I/O which this
649 task has caused. 604 task has caused.
650 605
651 Say N if unsure. 606 Say N if unsure.
652 607
653 config PSI 608 config PSI
654 bool "Pressure stall information track 609 bool "Pressure stall information tracking"
655 select KERNFS <<
656 help 610 help
657 Collect metrics that indicate how ov 611 Collect metrics that indicate how overcommitted the CPU, memory,
658 and IO capacity are in the system. 612 and IO capacity are in the system.
659 613
660 If you say Y here, the kernel will c 614 If you say Y here, the kernel will create /proc/pressure/ with the
661 pressure statistics files cpu, memor 615 pressure statistics files cpu, memory, and io. These will indicate
662 the share of walltime in which some 616 the share of walltime in which some or all tasks in the system are
663 delayed due to contention of the res 617 delayed due to contention of the respective resource.
664 618
665 In kernels with cgroup support, cgro 619 In kernels with cgroup support, cgroups (cgroup2 only) will
666 have cpu.pressure, memory.pressure, 620 have cpu.pressure, memory.pressure, and io.pressure files,
667 which aggregate pressure stalls for 621 which aggregate pressure stalls for the grouped tasks only.
668 622
669 For more details see Documentation/a 623 For more details see Documentation/accounting/psi.rst.
670 624
671 Say N if unsure. 625 Say N if unsure.
672 626
673 config PSI_DEFAULT_DISABLED 627 config PSI_DEFAULT_DISABLED
674 bool "Require boot parameter to enable 628 bool "Require boot parameter to enable pressure stall information tracking"
675 default n 629 default n
676 depends on PSI 630 depends on PSI
677 help 631 help
678 If set, pressure stall information t 632 If set, pressure stall information tracking will be disabled
679 per default but can be enabled throu 633 per default but can be enabled through passing psi=1 on the
680 kernel commandline during boot. 634 kernel commandline during boot.
681 635
682 This feature adds some code to the t 636 This feature adds some code to the task wakeup and sleep
683 paths of the scheduler. The overhead 637 paths of the scheduler. The overhead is too low to affect
684 common scheduling-intense workloads 638 common scheduling-intense workloads in practice (such as
685 webservers, memcache), but it does s 639 webservers, memcache), but it does show up in artificial
686 scheduler stress tests, such as hack 640 scheduler stress tests, such as hackbench.
687 641
688 If you are paranoid and not sure wha 642 If you are paranoid and not sure what the kernel will be
689 used for, say Y. 643 used for, say Y.
690 644
691 Say N if unsure. 645 Say N if unsure.
692 646
693 endmenu # "CPU/Task time and stats accounting" 647 endmenu # "CPU/Task time and stats accounting"
694 648
695 config CPU_ISOLATION 649 config CPU_ISOLATION
696 bool "CPU isolation" 650 bool "CPU isolation"
697 depends on SMP || COMPILE_TEST 651 depends on SMP || COMPILE_TEST
698 default y 652 default y
699 help 653 help
700 Make sure that CPUs running critical 654 Make sure that CPUs running critical tasks are not disturbed by
701 any source of "noise" such as unboun 655 any source of "noise" such as unbound workqueues, timers, kthreads...
702 Unbound jobs get offloaded to housek 656 Unbound jobs get offloaded to housekeeping CPUs. This is driven by
703 the "isolcpus=" boot parameter. 657 the "isolcpus=" boot parameter.
704 658
705 Say Y if unsure. 659 Say Y if unsure.
706 660
707 source "kernel/rcu/Kconfig" 661 source "kernel/rcu/Kconfig"
708 662
>> 663 config BUILD_BIN2C
>> 664 bool
>> 665 default n
>> 666
709 config IKCONFIG 667 config IKCONFIG
710 tristate "Kernel .config support" 668 tristate "Kernel .config support"
711 help 669 help
712 This option enables the complete Lin 670 This option enables the complete Linux kernel ".config" file
713 contents to be saved in the kernel. 671 contents to be saved in the kernel. It provides documentation
714 of which kernel options are used in 672 of which kernel options are used in a running kernel or in an
715 on-disk kernel. This information ca 673 on-disk kernel. This information can be extracted from the kernel
716 image file with the script scripts/e 674 image file with the script scripts/extract-ikconfig and used as
717 input to rebuild the current kernel 675 input to rebuild the current kernel or to build another kernel.
718 It can also be extracted from a runn 676 It can also be extracted from a running kernel by reading
719 /proc/config.gz if enabled (below). 677 /proc/config.gz if enabled (below).
720 678
721 config IKCONFIG_PROC 679 config IKCONFIG_PROC
722 bool "Enable access to .config through 680 bool "Enable access to .config through /proc/config.gz"
723 depends on IKCONFIG && PROC_FS 681 depends on IKCONFIG && PROC_FS
724 help 682 help
725 This option enables access to the ke 683 This option enables access to the kernel configuration file
726 through /proc/config.gz. 684 through /proc/config.gz.
727 685
728 config IKHEADERS 686 config IKHEADERS
729 tristate "Enable kernel headers throug 687 tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz"
730 depends on SYSFS 688 depends on SYSFS
731 help 689 help
732 This option enables access to the in 690 This option enables access to the in-kernel headers that are generated during
733 the build process. These can be used 691 the build process. These can be used to build eBPF tracing programs,
734 or similar programs. If you build t 692 or similar programs. If you build the headers as a module, a module called
735 kheaders.ko is built which can be lo 693 kheaders.ko is built which can be loaded on-demand to get access to headers.
736 694
737 config LOG_BUF_SHIFT 695 config LOG_BUF_SHIFT
738 int "Kernel log buffer size (16 => 64K 696 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
739 range 12 25 !! 697 range 12 25 if !H8300
>> 698 range 12 19 if H8300
740 default 17 699 default 17
741 depends on PRINTK 700 depends on PRINTK
742 help 701 help
743 Select the minimal kernel log buffer 702 Select the minimal kernel log buffer size as a power of 2.
744 The final size is affected by LOG_CP 703 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
745 parameter, see below. Any higher siz 704 parameter, see below. Any higher size also might be forced
746 by "log_buf_len" boot parameter. 705 by "log_buf_len" boot parameter.
747 706
748 Examples: 707 Examples:
749 17 => 128 KB 708 17 => 128 KB
750 16 => 64 KB 709 16 => 64 KB
751 15 => 32 KB 710 15 => 32 KB
752 14 => 16 KB 711 14 => 16 KB
753 13 => 8 KB 712 13 => 8 KB
754 12 => 4 KB 713 12 => 4 KB
755 714
756 config LOG_CPU_MAX_BUF_SHIFT 715 config LOG_CPU_MAX_BUF_SHIFT
757 int "CPU kernel log buffer size contri 716 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
758 depends on SMP 717 depends on SMP
759 range 0 21 718 range 0 21
>> 719 default 12 if !BASE_SMALL
760 default 0 if BASE_SMALL 720 default 0 if BASE_SMALL
761 default 12 <<
762 depends on PRINTK 721 depends on PRINTK
763 help 722 help
764 This option allows to increase the d 723 This option allows to increase the default ring buffer size
765 according to the number of CPUs. The 724 according to the number of CPUs. The value defines the contribution
766 of each CPU as a power of 2. The use 725 of each CPU as a power of 2. The used space is typically only few
767 lines however it might be much more 726 lines however it might be much more when problems are reported,
768 e.g. backtraces. 727 e.g. backtraces.
769 728
770 The increased size means that a new 729 The increased size means that a new buffer has to be allocated and
771 the original static one is unused. I 730 the original static one is unused. It makes sense only on systems
772 with more CPUs. Therefore this value 731 with more CPUs. Therefore this value is used only when the sum of
773 contributions is greater than the ha 732 contributions is greater than the half of the default kernel ring
774 buffer as defined by LOG_BUF_SHIFT. 733 buffer as defined by LOG_BUF_SHIFT. The default values are set
775 so that more than 16 CPUs are needed 734 so that more than 16 CPUs are needed to trigger the allocation.
776 735
777 Also this option is ignored when "lo 736 Also this option is ignored when "log_buf_len" kernel parameter is
778 used as it forces an exact (power of 737 used as it forces an exact (power of two) size of the ring buffer.
779 738
780 The number of possible CPUs is used 739 The number of possible CPUs is used for this computation ignoring
781 hotplugging making the computation o 740 hotplugging making the computation optimal for the worst case
782 scenario while allowing a simple alg 741 scenario while allowing a simple algorithm to be used from bootup.
783 742
784 Examples shift values and their mean 743 Examples shift values and their meaning:
785 17 => 128 KB for each CPU 744 17 => 128 KB for each CPU
786 16 => 64 KB for each CPU 745 16 => 64 KB for each CPU
787 15 => 32 KB for each CPU 746 15 => 32 KB for each CPU
788 14 => 16 KB for each CPU 747 14 => 16 KB for each CPU
789 13 => 8 KB for each CPU 748 13 => 8 KB for each CPU
790 12 => 4 KB for each CPU 749 12 => 4 KB for each CPU
791 750
792 config PRINTK_INDEX !! 751 config PRINTK_SAFE_LOG_BUF_SHIFT
793 bool "Printk indexing debugfs interfac !! 752 int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)"
794 depends on PRINTK && DEBUG_FS !! 753 range 10 21
795 help !! 754 default 13
796 Add support for indexing of all prin !! 755 depends on PRINTK
797 at <debugfs>/printk/index/<module>. !! 756 help
798 !! 757 Select the size of an alternate printk per-CPU buffer where messages
799 This can be used as part of maintain !! 758 printed from usafe contexts are temporary stored. One example would
800 /dev/kmsg, as it permits auditing th !! 759 be NMI messages, another one - printk recursion. The messages are
801 kernel, allowing detection of cases !! 760 copied to the main log buffer in a safe context to avoid a deadlock.
802 changed or no longer present. !! 761 The value defines the size as a power of 2.
>> 762
>> 763 Those messages are rare and limited. The largest one is when
>> 764 a backtrace is printed. It usually fits into 4KB. Select
>> 765 8KB if you want to be on the safe side.
803 766
804 There is no additional runtime cost !! 767 Examples:
>> 768 17 => 128 KB for each CPU
>> 769 16 => 64 KB for each CPU
>> 770 15 => 32 KB for each CPU
>> 771 14 => 16 KB for each CPU
>> 772 13 => 8 KB for each CPU
>> 773 12 => 4 KB for each CPU
805 774
806 # 775 #
807 # Architectures with an unreliable sched_clock 776 # Architectures with an unreliable sched_clock() should select this:
808 # 777 #
809 config HAVE_UNSTABLE_SCHED_CLOCK 778 config HAVE_UNSTABLE_SCHED_CLOCK
810 bool 779 bool
811 780
812 config GENERIC_SCHED_CLOCK 781 config GENERIC_SCHED_CLOCK
813 bool 782 bool
814 783
815 menu "Scheduler features" 784 menu "Scheduler features"
816 785
817 config UCLAMP_TASK 786 config UCLAMP_TASK
818 bool "Enable utilization clamping for 787 bool "Enable utilization clamping for RT/FAIR tasks"
819 depends on CPU_FREQ_GOV_SCHEDUTIL 788 depends on CPU_FREQ_GOV_SCHEDUTIL
820 help 789 help
821 This feature enables the scheduler t 790 This feature enables the scheduler to track the clamped utilization
822 of each CPU based on RUNNABLE tasks 791 of each CPU based on RUNNABLE tasks scheduled on that CPU.
823 792
824 With this option, the user can speci 793 With this option, the user can specify the min and max CPU
825 utilization allowed for RUNNABLE tas 794 utilization allowed for RUNNABLE tasks. The max utilization defines
826 the maximum frequency a task should 795 the maximum frequency a task should use while the min utilization
827 defines the minimum frequency it sho 796 defines the minimum frequency it should use.
828 797
829 Both min and max utilization clamp v 798 Both min and max utilization clamp values are hints to the scheduler,
830 aiming at improving its frequency se 799 aiming at improving its frequency selection policy, but they do not
831 enforce or grant any specific bandwi 800 enforce or grant any specific bandwidth for tasks.
832 801
833 If in doubt, say N. 802 If in doubt, say N.
834 803
835 config UCLAMP_BUCKETS_COUNT 804 config UCLAMP_BUCKETS_COUNT
836 int "Number of supported utilization c 805 int "Number of supported utilization clamp buckets"
837 range 5 20 806 range 5 20
838 default 5 807 default 5
839 depends on UCLAMP_TASK 808 depends on UCLAMP_TASK
840 help 809 help
841 Defines the number of clamp buckets 810 Defines the number of clamp buckets to use. The range of each bucket
842 will be SCHED_CAPACITY_SCALE/UCLAMP_ 811 will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the
843 number of clamp buckets the finer th 812 number of clamp buckets the finer their granularity and the higher
844 the precision of clamping aggregatio 813 the precision of clamping aggregation and tracking at run-time.
845 814
846 For example, with the minimum config 815 For example, with the minimum configuration value we will have 5
847 clamp buckets tracking 20% utilizati 816 clamp buckets tracking 20% utilization each. A 25% boosted tasks will
848 be refcounted in the [20..39]% bucke 817 be refcounted in the [20..39]% bucket and will set the bucket clamp
849 effective value to 25%. 818 effective value to 25%.
850 If a second 30% boosted task should 819 If a second 30% boosted task should be co-scheduled on the same CPU,
851 that task will be refcounted in the 820 that task will be refcounted in the same bucket of the first task and
852 it will boost the bucket clamp effec 821 it will boost the bucket clamp effective value to 30%.
853 The clamp effective value of a bucke 822 The clamp effective value of a bucket is reset to its nominal value
854 (20% in the example above) when ther 823 (20% in the example above) when there are no more tasks refcounted in
855 that bucket. 824 that bucket.
856 825
857 An additional boost/capping margin c 826 An additional boost/capping margin can be added to some tasks. In the
858 example above the 25% task will be b 827 example above the 25% task will be boosted to 30% until it exits the
859 CPU. If that should be considered no 828 CPU. If that should be considered not acceptable on certain systems,
860 it's always possible to reduce the m 829 it's always possible to reduce the margin by increasing the number of
861 clamp buckets to trade off used memo 830 clamp buckets to trade off used memory for run-time tracking
862 precision. 831 precision.
863 832
864 If in doubt, use the default value. 833 If in doubt, use the default value.
865 834
866 endmenu 835 endmenu
867 836
868 # 837 #
869 # For architectures that want to enable the su 838 # For architectures that want to enable the support for NUMA-affine scheduler
870 # balancing logic: 839 # balancing logic:
871 # 840 #
872 config ARCH_SUPPORTS_NUMA_BALANCING 841 config ARCH_SUPPORTS_NUMA_BALANCING
873 bool 842 bool
874 843
875 # 844 #
876 # For architectures that prefer to flush all T 845 # For architectures that prefer to flush all TLBs after a number of pages
877 # are unmapped instead of sending one IPI per 846 # are unmapped instead of sending one IPI per page to flush. The architecture
878 # must provide guarantees on what happens if a 847 # must provide guarantees on what happens if a clean TLB cache entry is
879 # written after the unmap. Details are in mm/r 848 # written after the unmap. Details are in mm/rmap.c near the check for
880 # should_defer_flush. The architecture should 849 # should_defer_flush. The architecture should also consider if the full flush
881 # and the refill costs are offset by the savin 850 # and the refill costs are offset by the savings of sending fewer IPIs.
882 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 851 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
883 bool 852 bool
884 853
885 config CC_HAS_INT128 854 config CC_HAS_INT128
886 def_bool !$(cc-option,$(m64-flag) -D__ 855 def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT
887 856
888 config CC_IMPLICIT_FALLTHROUGH <<
889 string <<
890 default "-Wimplicit-fallthrough=5" if <<
891 default "-Wimplicit-fallthrough" if CC <<
892 <<
893 # Currently, disable gcc-10+ array-bounds glob <<
894 # It's still broken in gcc-13, so no upper bou <<
895 config GCC10_NO_ARRAY_BOUNDS <<
896 def_bool y <<
897 <<
898 config CC_NO_ARRAY_BOUNDS <<
899 bool <<
900 default y if CC_IS_GCC && GCC_VERSION <<
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 <<
914 # 857 #
915 # For architectures that know their GCC __int1 858 # For architectures that know their GCC __int128 support is sound
916 # 859 #
917 config ARCH_SUPPORTS_INT128 860 config ARCH_SUPPORTS_INT128
918 bool 861 bool
919 862
920 # For architectures that (ab)use NUMA to repre 863 # For architectures that (ab)use NUMA to represent different memory regions
921 # all cpu-local but of different latencies, su 864 # all cpu-local but of different latencies, such as SuperH.
922 # 865 #
923 config ARCH_WANT_NUMA_VARIABLE_LOCALITY 866 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
924 bool 867 bool
925 868
926 config NUMA_BALANCING 869 config NUMA_BALANCING
927 bool "Memory placement aware NUMA sche 870 bool "Memory placement aware NUMA scheduler"
928 depends on ARCH_SUPPORTS_NUMA_BALANCIN 871 depends on ARCH_SUPPORTS_NUMA_BALANCING
929 depends on !ARCH_WANT_NUMA_VARIABLE_LO 872 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
930 depends on SMP && NUMA && MIGRATION && !! 873 depends on SMP && NUMA && MIGRATION
931 help 874 help
932 This option adds support for automat 875 This option adds support for automatic NUMA aware memory/task placement.
933 The mechanism is quite primitive and 876 The mechanism is quite primitive and is based on migrating memory when
934 it has references to the node the ta 877 it has references to the node the task is running on.
935 878
936 This system will be inactive on UMA 879 This system will be inactive on UMA systems.
937 880
938 config NUMA_BALANCING_DEFAULT_ENABLED 881 config NUMA_BALANCING_DEFAULT_ENABLED
939 bool "Automatically enable NUMA aware 882 bool "Automatically enable NUMA aware memory/task placement"
940 default y 883 default y
941 depends on NUMA_BALANCING 884 depends on NUMA_BALANCING
942 help 885 help
943 If set, automatic NUMA balancing wil 886 If set, automatic NUMA balancing will be enabled if running on a NUMA
944 machine. 887 machine.
945 888
946 config SLAB_OBJ_EXT <<
947 bool <<
948 <<
949 menuconfig CGROUPS 889 menuconfig CGROUPS
950 bool "Control Group support" 890 bool "Control Group support"
951 select KERNFS 891 select KERNFS
952 help 892 help
953 This option adds support for groupin 893 This option adds support for grouping sets of processes together, for
954 use with process control subsystems 894 use with process control subsystems such as Cpusets, CFS, memory
955 controls or device isolation. 895 controls or device isolation.
956 See 896 See
957 - Documentation/scheduler/sche 897 - Documentation/scheduler/sched-design-CFS.rst (CFS)
958 - Documentation/admin-guide/cg 898 - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation
959 and 899 and resource control)
960 900
961 Say N if unsure. 901 Say N if unsure.
962 902
963 if CGROUPS 903 if CGROUPS
964 904
965 config PAGE_COUNTER 905 config PAGE_COUNTER
966 bool 906 bool
967 907
968 config CGROUP_FAVOR_DYNMODS <<
969 bool "Favor dynamic modification laten <<
970 help <<
971 This option enables the "favordynmod <<
972 which reduces the latencies of dynam <<
973 as task migrations and controller on <<
974 hot path operations such as forks an <<
975 <<
976 Say N if unsure. <<
977 <<
978 config MEMCG 908 config MEMCG
979 bool "Memory controller" 909 bool "Memory controller"
980 select PAGE_COUNTER 910 select PAGE_COUNTER
981 select EVENTFD 911 select EVENTFD
982 select SLAB_OBJ_EXT <<
983 help 912 help
984 Provides control over the memory foo 913 Provides control over the memory footprint of tasks in a cgroup.
985 914
986 config MEMCG_V1 !! 915 config MEMCG_SWAP
987 bool "Legacy cgroup v1 memory controll !! 916 bool
988 depends on MEMCG !! 917 depends on MEMCG && SWAP
989 default n !! 918 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 919
1001 Say N if unsure. !! 920 config MEMCG_KMEM
>> 921 bool
>> 922 depends on MEMCG && !SLOB
>> 923 default y
1002 924
1003 config BLK_CGROUP 925 config BLK_CGROUP
1004 bool "IO controller" 926 bool "IO controller"
1005 depends on BLOCK 927 depends on BLOCK
1006 default n 928 default n
1007 help 929 help
1008 Generic block IO controller cgroup in 930 Generic block IO controller cgroup interface. This is the common
1009 cgroup interface which should be used 931 cgroup interface which should be used by various IO controlling
1010 policies. 932 policies.
1011 933
1012 Currently, CFQ IO scheduler uses it t 934 Currently, CFQ IO scheduler uses it to recognize task groups and
1013 control disk bandwidth allocation (pr 935 control disk bandwidth allocation (proportional time slice allocation)
1014 to such task groups. It is also used 936 to such task groups. It is also used by bio throttling logic in
1015 block layer to implement upper limit 937 block layer to implement upper limit in IO rates on a device.
1016 938
1017 This option only enables generic Bloc 939 This option only enables generic Block IO controller infrastructure.
1018 One needs to also enable actual IO co 940 One needs to also enable actual IO controlling logic/policy. For
1019 enabling proportional weight division 941 enabling proportional weight division of disk bandwidth in CFQ, set
1020 CONFIG_BFQ_GROUP_IOSCHED=y; for enabl 942 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1021 CONFIG_BLK_DEV_THROTTLING=y. 943 CONFIG_BLK_DEV_THROTTLING=y.
1022 944
1023 See Documentation/admin-guide/cgroup- 945 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information.
1024 946
1025 config CGROUP_WRITEBACK 947 config CGROUP_WRITEBACK
1026 bool 948 bool
1027 depends on MEMCG && BLK_CGROUP 949 depends on MEMCG && BLK_CGROUP
1028 default y 950 default y
1029 951
1030 menuconfig CGROUP_SCHED 952 menuconfig CGROUP_SCHED
1031 bool "CPU controller" 953 bool "CPU controller"
1032 default n 954 default n
1033 help 955 help
1034 This feature lets CPU scheduler rec 956 This feature lets CPU scheduler recognize task groups and control CPU
1035 bandwidth allocation to such task g 957 bandwidth allocation to such task groups. It uses cgroups to group
1036 tasks. 958 tasks.
1037 959
1038 if CGROUP_SCHED 960 if CGROUP_SCHED
1039 config GROUP_SCHED_WEIGHT <<
1040 def_bool n <<
1041 <<
1042 config FAIR_GROUP_SCHED 961 config FAIR_GROUP_SCHED
1043 bool "Group scheduling for SCHED_OTHE 962 bool "Group scheduling for SCHED_OTHER"
1044 depends on CGROUP_SCHED 963 depends on CGROUP_SCHED
1045 select GROUP_SCHED_WEIGHT <<
1046 default CGROUP_SCHED 964 default CGROUP_SCHED
1047 965
1048 config CFS_BANDWIDTH 966 config CFS_BANDWIDTH
1049 bool "CPU bandwidth provisioning for 967 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1050 depends on FAIR_GROUP_SCHED 968 depends on FAIR_GROUP_SCHED
1051 default n 969 default n
1052 help 970 help
1053 This option allows users to define 971 This option allows users to define CPU bandwidth rates (limits) for
1054 tasks running within the fair group 972 tasks running within the fair group scheduler. Groups with no limit
1055 set are considered to be unconstrai 973 set are considered to be unconstrained and will run with no
1056 restriction. 974 restriction.
1057 See Documentation/scheduler/sched-b 975 See Documentation/scheduler/sched-bwc.rst for more information.
1058 976
1059 config RT_GROUP_SCHED 977 config RT_GROUP_SCHED
1060 bool "Group scheduling for SCHED_RR/F 978 bool "Group scheduling for SCHED_RR/FIFO"
1061 depends on CGROUP_SCHED 979 depends on CGROUP_SCHED
1062 default n 980 default n
1063 help 981 help
1064 This feature lets you explicitly al 982 This feature lets you explicitly allocate real CPU bandwidth
1065 to task groups. If enabled, it will 983 to task groups. If enabled, it will also make it impossible to
1066 schedule realtime tasks for non-roo 984 schedule realtime tasks for non-root users until you allocate
1067 realtime bandwidth for them. 985 realtime bandwidth for them.
1068 See Documentation/scheduler/sched-r 986 See Documentation/scheduler/sched-rt-group.rst for more information.
1069 987
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 988 endif #CGROUP_SCHED
1077 989
1078 config SCHED_MM_CID <<
1079 def_bool y <<
1080 depends on SMP && RSEQ <<
1081 <<
1082 config UCLAMP_TASK_GROUP 990 config UCLAMP_TASK_GROUP
1083 bool "Utilization clamping per group 991 bool "Utilization clamping per group of tasks"
1084 depends on CGROUP_SCHED 992 depends on CGROUP_SCHED
1085 depends on UCLAMP_TASK 993 depends on UCLAMP_TASK
1086 default n 994 default n
1087 help 995 help
1088 This feature enables the scheduler 996 This feature enables the scheduler to track the clamped utilization
1089 of each CPU based on RUNNABLE tasks 997 of each CPU based on RUNNABLE tasks currently scheduled on that CPU.
1090 998
1091 When this option is enabled, the us 999 When this option is enabled, the user can specify a min and max
1092 CPU bandwidth which is allowed for 1000 CPU bandwidth which is allowed for each single task in a group.
1093 The max bandwidth allows to clamp t 1001 The max bandwidth allows to clamp the maximum frequency a task
1094 can use, while the min bandwidth al 1002 can use, while the min bandwidth allows to define a minimum
1095 frequency a task will always use. 1003 frequency a task will always use.
1096 1004
1097 When task group based utilization c 1005 When task group based utilization clamping is enabled, an eventually
1098 specified task-specific clamp value 1006 specified task-specific clamp value is constrained by the cgroup
1099 specified clamp value. Both minimum 1007 specified clamp value. Both minimum and maximum task clamping cannot
1100 be bigger than the corresponding cl 1008 be bigger than the corresponding clamping defined at task group level.
1101 1009
1102 If in doubt, say N. 1010 If in doubt, say N.
1103 1011
1104 config CGROUP_PIDS 1012 config CGROUP_PIDS
1105 bool "PIDs controller" 1013 bool "PIDs controller"
1106 help 1014 help
1107 Provides enforcement of process num 1015 Provides enforcement of process number limits in the scope of a
1108 cgroup. Any attempt to fork more pr 1016 cgroup. Any attempt to fork more processes than is allowed in the
1109 cgroup will fail. PIDs are fundamen 1017 cgroup will fail. PIDs are fundamentally a global resource because it
1110 is fairly trivial to reach PID exha 1018 is fairly trivial to reach PID exhaustion before you reach even a
1111 conservative kmemcg limit. As a res 1019 conservative kmemcg limit. As a result, it is possible to grind a
1112 system to halt without being limite 1020 system to halt without being limited by other cgroup policies. The
1113 PIDs controller is designed to stop 1021 PIDs controller is designed to stop this from happening.
1114 1022
1115 It should be noted that organisatio 1023 It should be noted that organisational operations (such as attaching
1116 to a cgroup hierarchy) will *not* b 1024 to a cgroup hierarchy) will *not* be blocked by the PIDs controller,
1117 since the PIDs limit only affects a 1025 since the PIDs limit only affects a process's ability to fork, not to
1118 attach to a cgroup. 1026 attach to a cgroup.
1119 1027
1120 config CGROUP_RDMA 1028 config CGROUP_RDMA
1121 bool "RDMA controller" 1029 bool "RDMA controller"
1122 help 1030 help
1123 Provides enforcement of RDMA resour 1031 Provides enforcement of RDMA resources defined by IB stack.
1124 It is fairly easy for consumers to 1032 It is fairly easy for consumers to exhaust RDMA resources, which
1125 can result into resource unavailabi 1033 can result into resource unavailability to other consumers.
1126 RDMA controller is designed to stop 1034 RDMA controller is designed to stop this from happening.
1127 Attaching processes with active RDM 1035 Attaching processes with active RDMA resources to the cgroup
1128 hierarchy is allowed even if can cr 1036 hierarchy is allowed even if can cross the hierarchy's limit.
1129 1037
1130 config CGROUP_FREEZER 1038 config CGROUP_FREEZER
1131 bool "Freezer controller" 1039 bool "Freezer controller"
1132 help 1040 help
1133 Provides a way to freeze and unfree 1041 Provides a way to freeze and unfreeze all tasks in a
1134 cgroup. 1042 cgroup.
1135 1043
1136 This option affects the ORIGINAL cg 1044 This option affects the ORIGINAL cgroup interface. The cgroup2 memory
1137 controller includes important in-ke 1045 controller includes important in-kernel memory consumers per default.
1138 1046
1139 If you're using cgroup2, say N. 1047 If you're using cgroup2, say N.
1140 1048
1141 config CGROUP_HUGETLB 1049 config CGROUP_HUGETLB
1142 bool "HugeTLB controller" 1050 bool "HugeTLB controller"
1143 depends on HUGETLB_PAGE 1051 depends on HUGETLB_PAGE
1144 select PAGE_COUNTER 1052 select PAGE_COUNTER
1145 default n 1053 default n
1146 help 1054 help
1147 Provides a cgroup controller for Hu 1055 Provides a cgroup controller for HugeTLB pages.
1148 When you enable this, you can put a 1056 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1149 The limit is enforced during page f 1057 The limit is enforced during page fault. Since HugeTLB doesn't
1150 support page reclaim, enforcing the 1058 support page reclaim, enforcing the limit at page fault time implies
1151 that, the application will get SIGB 1059 that, the application will get SIGBUS signal if it tries to access
1152 HugeTLB pages beyond its limit. Thi 1060 HugeTLB pages beyond its limit. This requires the application to know
1153 beforehand how much HugeTLB pages i 1061 beforehand how much HugeTLB pages it would require for its use. The
1154 control group is tracked in the thi 1062 control group is tracked in the third page lru pointer. This means
1155 that we cannot use the controller w 1063 that we cannot use the controller with huge page less than 3 pages.
1156 1064
1157 config CPUSETS 1065 config CPUSETS
1158 bool "Cpuset controller" 1066 bool "Cpuset controller"
1159 depends on SMP 1067 depends on SMP
1160 help 1068 help
1161 This option will let you create and 1069 This option will let you create and manage CPUSETs which
1162 allow dynamically partitioning a sy 1070 allow dynamically partitioning a system into sets of CPUs and
1163 Memory Nodes and assigning tasks to 1071 Memory Nodes and assigning tasks to run only within those sets.
1164 This is primarily useful on large S 1072 This is primarily useful on large SMP or NUMA systems.
1165 1073
1166 Say N if unsure. 1074 Say N if unsure.
1167 1075
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 1076 config PROC_PID_CPUSET
1182 bool "Include legacy /proc/<pid>/cpus 1077 bool "Include legacy /proc/<pid>/cpuset file"
1183 depends on CPUSETS 1078 depends on CPUSETS
1184 default y 1079 default y
1185 1080
1186 config CGROUP_DEVICE 1081 config CGROUP_DEVICE
1187 bool "Device controller" 1082 bool "Device controller"
1188 help 1083 help
1189 Provides a cgroup controller implem 1084 Provides a cgroup controller implementing whitelists for
1190 devices which a process in the cgro 1085 devices which a process in the cgroup can mknod or open.
1191 1086
1192 config CGROUP_CPUACCT 1087 config CGROUP_CPUACCT
1193 bool "Simple CPU accounting controlle 1088 bool "Simple CPU accounting controller"
1194 help 1089 help
1195 Provides a simple controller for mo 1090 Provides a simple controller for monitoring the
1196 total CPU consumed by the tasks in 1091 total CPU consumed by the tasks in a cgroup.
1197 1092
1198 config CGROUP_PERF 1093 config CGROUP_PERF
1199 bool "Perf controller" 1094 bool "Perf controller"
1200 depends on PERF_EVENTS 1095 depends on PERF_EVENTS
1201 help 1096 help
1202 This option extends the perf per-cp 1097 This option extends the perf per-cpu mode to restrict monitoring
1203 to threads which belong to the cgro 1098 to threads which belong to the cgroup specified and run on the
1204 designated cpu. Or this can be use 1099 designated cpu. Or this can be used to have cgroup ID in samples
1205 so that it can monitor performance 1100 so that it can monitor performance events among cgroups.
1206 1101
1207 Say N if unsure. 1102 Say N if unsure.
1208 1103
1209 config CGROUP_BPF 1104 config CGROUP_BPF
1210 bool "Support for eBPF programs attac 1105 bool "Support for eBPF programs attached to cgroups"
1211 depends on BPF_SYSCALL 1106 depends on BPF_SYSCALL
1212 select SOCK_CGROUP_DATA 1107 select SOCK_CGROUP_DATA
1213 help 1108 help
1214 Allow attaching eBPF programs to a 1109 Allow attaching eBPF programs to a cgroup using the bpf(2)
1215 syscall command BPF_PROG_ATTACH. 1110 syscall command BPF_PROG_ATTACH.
1216 1111
1217 In which context these programs are 1112 In which context these programs are accessed depends on the type
1218 of attachment. For instance, progra 1113 of attachment. For instance, programs that are attached using
1219 BPF_CGROUP_INET_INGRESS will be exe 1114 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
1220 inet sockets. 1115 inet sockets.
1221 1116
1222 config CGROUP_MISC 1117 config CGROUP_MISC
1223 bool "Misc resource controller" 1118 bool "Misc resource controller"
1224 default n 1119 default n
1225 help 1120 help
1226 Provides a controller for miscellan 1121 Provides a controller for miscellaneous resources on a host.
1227 1122
1228 Miscellaneous scalar resources are 1123 Miscellaneous scalar resources are the resources on the host system
1229 which cannot be abstracted like the 1124 which cannot be abstracted like the other cgroups. This controller
1230 tracks and limits the miscellaneous 1125 tracks and limits the miscellaneous resources used by a process
1231 attached to a cgroup hierarchy. 1126 attached to a cgroup hierarchy.
1232 1127
1233 For more information, please check 1128 For more information, please check misc cgroup section in
1234 /Documentation/admin-guide/cgroup-v 1129 /Documentation/admin-guide/cgroup-v2.rst.
1235 1130
1236 config CGROUP_DEBUG 1131 config CGROUP_DEBUG
1237 bool "Debug controller" 1132 bool "Debug controller"
1238 default n 1133 default n
1239 depends on DEBUG_KERNEL 1134 depends on DEBUG_KERNEL
1240 help 1135 help
1241 This option enables a simple contro 1136 This option enables a simple controller that exports
1242 debugging information about the cgr 1137 debugging information about the cgroups framework. This
1243 controller is for control cgroup de 1138 controller is for control cgroup debugging only. Its
1244 interfaces are not stable. 1139 interfaces are not stable.
1245 1140
1246 Say N. 1141 Say N.
1247 1142
1248 config SOCK_CGROUP_DATA 1143 config SOCK_CGROUP_DATA
1249 bool 1144 bool
1250 default n 1145 default n
1251 1146
1252 endif # CGROUPS 1147 endif # CGROUPS
1253 1148
1254 menuconfig NAMESPACES 1149 menuconfig NAMESPACES
1255 bool "Namespaces support" if EXPERT 1150 bool "Namespaces support" if EXPERT
1256 depends on MULTIUSER 1151 depends on MULTIUSER
1257 default !EXPERT 1152 default !EXPERT
1258 help 1153 help
1259 Provides the way to make tasks work 1154 Provides the way to make tasks work with different objects using
1260 the same id. For example same IPC i 1155 the same id. For example same IPC id may refer to different objects
1261 or same user id or pid may refer to 1156 or same user id or pid may refer to different tasks when used in
1262 different namespaces. 1157 different namespaces.
1263 1158
1264 if NAMESPACES 1159 if NAMESPACES
1265 1160
1266 config UTS_NS 1161 config UTS_NS
1267 bool "UTS namespace" 1162 bool "UTS namespace"
1268 default y 1163 default y
1269 help 1164 help
1270 In this namespace tasks see differe 1165 In this namespace tasks see different info provided with the
1271 uname() system call 1166 uname() system call
1272 1167
1273 config TIME_NS 1168 config TIME_NS
1274 bool "TIME namespace" 1169 bool "TIME namespace"
1275 depends on GENERIC_VDSO_TIME_NS 1170 depends on GENERIC_VDSO_TIME_NS
1276 default y 1171 default y
1277 help 1172 help
1278 In this namespace boottime and mono 1173 In this namespace boottime and monotonic clocks can be set.
1279 The time will keep going with the s 1174 The time will keep going with the same pace.
1280 1175
1281 config IPC_NS 1176 config IPC_NS
1282 bool "IPC namespace" 1177 bool "IPC namespace"
1283 depends on (SYSVIPC || POSIX_MQUEUE) 1178 depends on (SYSVIPC || POSIX_MQUEUE)
1284 default y 1179 default y
1285 help 1180 help
1286 In this namespace tasks work with I 1181 In this namespace tasks work with IPC ids which correspond to
1287 different IPC objects in different 1182 different IPC objects in different namespaces.
1288 1183
1289 config USER_NS 1184 config USER_NS
1290 bool "User namespace" 1185 bool "User namespace"
1291 default n 1186 default n
1292 help 1187 help
1293 This allows containers, i.e. vserve 1188 This allows containers, i.e. vservers, to use user namespaces
1294 to provide different user info for 1189 to provide different user info for different servers.
1295 1190
1296 When user namespaces are enabled in 1191 When user namespaces are enabled in the kernel it is
1297 recommended that the MEMCG option a 1192 recommended that the MEMCG option also be enabled and that
1298 user-space use the memory control g 1193 user-space use the memory control groups to limit the amount
1299 of memory a memory unprivileged use 1194 of memory a memory unprivileged users can use.
1300 1195
1301 If unsure, say N. 1196 If unsure, say N.
1302 1197
1303 config PID_NS 1198 config PID_NS
1304 bool "PID Namespaces" 1199 bool "PID Namespaces"
1305 default y 1200 default y
1306 help 1201 help
1307 Support process id namespaces. Thi 1202 Support process id namespaces. This allows having multiple
1308 processes with the same pid as long 1203 processes with the same pid as long as they are in different
1309 pid namespaces. This is a building 1204 pid namespaces. This is a building block of containers.
1310 1205
1311 config NET_NS 1206 config NET_NS
1312 bool "Network namespace" 1207 bool "Network namespace"
1313 depends on NET 1208 depends on NET
1314 default y 1209 default y
1315 help 1210 help
1316 Allow user space to create what app 1211 Allow user space to create what appear to be multiple instances
1317 of the network stack. 1212 of the network stack.
1318 1213
1319 endif # NAMESPACES 1214 endif # NAMESPACES
1320 1215
1321 config CHECKPOINT_RESTORE 1216 config CHECKPOINT_RESTORE
1322 bool "Checkpoint/restore support" 1217 bool "Checkpoint/restore support"
1323 depends on PROC_FS <<
1324 select PROC_CHILDREN 1218 select PROC_CHILDREN
1325 select KCMP 1219 select KCMP
1326 default n 1220 default n
1327 help 1221 help
1328 Enables additional kernel features 1222 Enables additional kernel features in a sake of checkpoint/restore.
1329 In particular it adds auxiliary prc 1223 In particular it adds auxiliary prctl codes to setup process text,
1330 data and heap segment sizes, and a 1224 data and heap segment sizes, and a few additional /proc filesystem
1331 entries. 1225 entries.
1332 1226
1333 If unsure, say N here. 1227 If unsure, say N here.
1334 1228
1335 config SCHED_AUTOGROUP 1229 config SCHED_AUTOGROUP
1336 bool "Automatic process group schedul 1230 bool "Automatic process group scheduling"
1337 select CGROUPS 1231 select CGROUPS
1338 select CGROUP_SCHED 1232 select CGROUP_SCHED
1339 select FAIR_GROUP_SCHED 1233 select FAIR_GROUP_SCHED
1340 help 1234 help
1341 This option optimizes the scheduler 1235 This option optimizes the scheduler for common desktop workloads by
1342 automatically creating and populati 1236 automatically creating and populating task groups. This separation
1343 of workloads isolates aggressive CP 1237 of workloads isolates aggressive CPU burners (like build jobs) from
1344 desktop applications. Task group a 1238 desktop applications. Task group autogeneration is currently based
1345 upon task session. 1239 upon task session.
1346 1240
>> 1241 config SYSFS_DEPRECATED
>> 1242 bool "Enable deprecated sysfs features to support old userspace tools"
>> 1243 depends on SYSFS
>> 1244 default n
>> 1245 help
>> 1246 This option adds code that switches the layout of the "block" class
>> 1247 devices, to not show up in /sys/class/block/, but only in
>> 1248 /sys/block/.
>> 1249
>> 1250 This switch is only active when the sysfs.deprecated=1 boot option is
>> 1251 passed or the SYSFS_DEPRECATED_V2 option is set.
>> 1252
>> 1253 This option allows new kernels to run on old distributions and tools,
>> 1254 which might get confused by /sys/class/block/. Since 2007/2008 all
>> 1255 major distributions and tools handle this just fine.
>> 1256
>> 1257 Recent distributions and userspace tools after 2009/2010 depend on
>> 1258 the existence of /sys/class/block/, and will not work with this
>> 1259 option enabled.
>> 1260
>> 1261 Only if you are using a new kernel on an old distribution, you might
>> 1262 need to say Y here.
>> 1263
>> 1264 config SYSFS_DEPRECATED_V2
>> 1265 bool "Enable deprecated sysfs features by default"
>> 1266 default n
>> 1267 depends on SYSFS
>> 1268 depends on SYSFS_DEPRECATED
>> 1269 help
>> 1270 Enable deprecated sysfs by default.
>> 1271
>> 1272 See the CONFIG_SYSFS_DEPRECATED option for more details about this
>> 1273 option.
>> 1274
>> 1275 Only if you are using a new kernel on an old distribution, you might
>> 1276 need to say Y here. Even then, odds are you would not need it
>> 1277 enabled, you can always pass the boot option if absolutely necessary.
>> 1278
1347 config RELAY 1279 config RELAY
1348 bool "Kernel->user space relay suppor 1280 bool "Kernel->user space relay support (formerly relayfs)"
1349 select IRQ_WORK 1281 select IRQ_WORK
1350 help 1282 help
1351 This option enables support for rel 1283 This option enables support for relay interface support in
1352 certain file systems (such as debug 1284 certain file systems (such as debugfs).
1353 It is designed to provide an effici 1285 It is designed to provide an efficient mechanism for tools and
1354 facilities to relay large amounts o 1286 facilities to relay large amounts of data from kernel space to
1355 user space. 1287 user space.
1356 1288
1357 If unsure, say N. 1289 If unsure, say N.
1358 1290
1359 config BLK_DEV_INITRD 1291 config BLK_DEV_INITRD
1360 bool "Initial RAM filesystem and RAM 1292 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1361 help 1293 help
1362 The initial RAM filesystem is a ram 1294 The initial RAM filesystem is a ramfs which is loaded by the
1363 boot loader (loadlin or lilo) and t 1295 boot loader (loadlin or lilo) and that is mounted as root
1364 before the normal boot procedure. I 1296 before the normal boot procedure. It is typically used to
1365 load modules needed to mount the "r 1297 load modules needed to mount the "real" root file system,
1366 etc. See <file:Documentation/admin- 1298 etc. See <file:Documentation/admin-guide/initrd.rst> for details.
1367 1299
1368 If RAM disk support (BLK_DEV_RAM) i 1300 If RAM disk support (BLK_DEV_RAM) is also included, this
1369 also enables initial RAM disk (init 1301 also enables initial RAM disk (initrd) support and adds
1370 15 Kbytes (more on some other archi 1302 15 Kbytes (more on some other architectures) to the kernel size.
1371 1303
1372 If unsure say Y. 1304 If unsure say Y.
1373 1305
1374 if BLK_DEV_INITRD 1306 if BLK_DEV_INITRD
1375 1307
1376 source "usr/Kconfig" 1308 source "usr/Kconfig"
1377 1309
1378 endif 1310 endif
1379 1311
1380 config BOOT_CONFIG 1312 config BOOT_CONFIG
1381 bool "Boot config support" 1313 bool "Boot config support"
1382 select BLK_DEV_INITRD if !BOOT_CONFIG !! 1314 select BLK_DEV_INITRD
1383 help 1315 help
1384 Extra boot config allows system adm 1316 Extra boot config allows system admin to pass a config file as
1385 complemental extension of kernel cm 1317 complemental extension of kernel cmdline when booting.
1386 The boot config file must be attach 1318 The boot config file must be attached at the end of initramfs
1387 with checksum, size and magic word. 1319 with checksum, size and magic word.
1388 See <file:Documentation/admin-guide 1320 See <file:Documentation/admin-guide/bootconfig.rst> for details.
1389 1321
1390 If unsure, say Y. 1322 If unsure, say Y.
1391 1323
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 <<
1406 bool "Embed bootconfig file in the ke <<
1407 depends on BOOT_CONFIG <<
1408 help <<
1409 Embed a bootconfig file given by BO <<
1410 kernel. Usually, the bootconfig fil <<
1411 image. But if the system doesn't su <<
1412 help you by embedding a bootconfig <<
1413 <<
1414 If unsure, say N. <<
1415 <<
1416 config BOOT_CONFIG_EMBED_FILE <<
1417 string "Embedded bootconfig file path <<
1418 depends on BOOT_CONFIG_EMBED <<
1419 help <<
1420 Specify a bootconfig file which wil <<
1421 This bootconfig will be used if the <<
1422 bootconfig in the initrd. <<
1423 <<
1424 config INITRAMFS_PRESERVE_MTIME <<
1425 bool "Preserve cpio archive mtimes in <<
1426 default y <<
1427 help <<
1428 Each entry in an initramfs cpio arc <<
1429 enabled, extracted cpio items take <<
1430 setting deferred until after creati <<
1431 <<
1432 If unsure, say Y. <<
1433 <<
1434 choice 1324 choice
1435 prompt "Compiler optimization level" 1325 prompt "Compiler optimization level"
1436 default CC_OPTIMIZE_FOR_PERFORMANCE 1326 default CC_OPTIMIZE_FOR_PERFORMANCE
1437 1327
1438 config CC_OPTIMIZE_FOR_PERFORMANCE 1328 config CC_OPTIMIZE_FOR_PERFORMANCE
1439 bool "Optimize for performance (-O2)" 1329 bool "Optimize for performance (-O2)"
1440 help 1330 help
1441 This is the default optimization le 1331 This is the default optimization level for the kernel, building
1442 with the "-O2" compiler flag for be 1332 with the "-O2" compiler flag for best performance and most
1443 helpful compile-time warnings. 1333 helpful compile-time warnings.
1444 1334
>> 1335 config CC_OPTIMIZE_FOR_PERFORMANCE_O3
>> 1336 bool "Optimize more for performance (-O3)"
>> 1337 depends on ARC
>> 1338 help
>> 1339 Choosing this option will pass "-O3" to your compiler to optimize
>> 1340 the kernel yet more for performance.
>> 1341
1445 config CC_OPTIMIZE_FOR_SIZE 1342 config CC_OPTIMIZE_FOR_SIZE
1446 bool "Optimize for size (-Os)" 1343 bool "Optimize for size (-Os)"
1447 help 1344 help
1448 Choosing this option will pass "-Os 1345 Choosing this option will pass "-Os" to your compiler resulting
1449 in a smaller kernel. 1346 in a smaller kernel.
1450 1347
1451 endchoice 1348 endchoice
1452 1349
1453 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1350 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1454 bool 1351 bool
1455 help 1352 help
1456 This requires that the arch annotat 1353 This requires that the arch annotates or otherwise protects
1457 its external entry points from bein 1354 its external entry points from being discarded. Linker scripts
1458 must also merge .text.*, .data.*, a 1355 must also merge .text.*, .data.*, and .bss.* correctly into
1459 output sections. Care must be taken 1356 output sections. Care must be taken not to pull in unrelated
1460 sections (e.g., '.text.init'). Typi 1357 sections (e.g., '.text.init'). Typically '.' in section names
1461 is used to distinguish them from la 1358 is used to distinguish them from label names / C identifiers.
1462 1359
1463 config LD_DEAD_CODE_DATA_ELIMINATION 1360 config LD_DEAD_CODE_DATA_ELIMINATION
1464 bool "Dead code and data elimination 1361 bool "Dead code and data elimination (EXPERIMENTAL)"
1465 depends on HAVE_LD_DEAD_CODE_DATA_ELI 1362 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1466 depends on EXPERT 1363 depends on EXPERT
1467 depends on $(cc-option,-ffunction-sec 1364 depends on $(cc-option,-ffunction-sections -fdata-sections)
1468 depends on $(ld-option,--gc-sections) 1365 depends on $(ld-option,--gc-sections)
1469 help 1366 help
1470 Enable this if you want to do dead 1367 Enable this if you want to do dead code and data elimination with
1471 the linker by compiling with -ffunc 1368 the linker by compiling with -ffunction-sections -fdata-sections,
1472 and linking with --gc-sections. 1369 and linking with --gc-sections.
1473 1370
1474 This can reduce on disk and in-memo 1371 This can reduce on disk and in-memory size of the kernel
1475 code and static data, particularly 1372 code and static data, particularly for small configs and
1476 on small systems. This has the poss 1373 on small systems. This has the possibility of introducing
1477 silently broken kernel if the requi 1374 silently broken kernel if the required annotations are not
1478 present. This option is not well te 1375 present. This option is not well tested yet, so use at your
1479 own risk. 1376 own risk.
1480 1377
1481 config LD_ORPHAN_WARN 1378 config LD_ORPHAN_WARN
1482 def_bool y 1379 def_bool y
1483 depends on ARCH_WANT_LD_ORPHAN_WARN 1380 depends on ARCH_WANT_LD_ORPHAN_WARN
>> 1381 depends on !LD_IS_LLD || LLD_VERSION >= 110000
1484 depends on $(ld-option,--orphan-handl 1382 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 1383
1493 config SYSCTL 1384 config SYSCTL
1494 bool 1385 bool
1495 1386
1496 config HAVE_UID16 1387 config HAVE_UID16
1497 bool 1388 bool
1498 1389
1499 config SYSCTL_EXCEPTION_TRACE 1390 config SYSCTL_EXCEPTION_TRACE
1500 bool 1391 bool
1501 help 1392 help
1502 Enable support for /proc/sys/debug/ 1393 Enable support for /proc/sys/debug/exception-trace.
1503 1394
1504 config SYSCTL_ARCH_UNALIGN_NO_WARN 1395 config SYSCTL_ARCH_UNALIGN_NO_WARN
1505 bool 1396 bool
1506 help 1397 help
1507 Enable support for /proc/sys/kernel 1398 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1508 Allows arch to define/use @no_unali 1399 Allows arch to define/use @no_unaligned_warning to possibly warn
1509 about unaligned access emulation go 1400 about unaligned access emulation going on under the hood.
1510 1401
1511 config SYSCTL_ARCH_UNALIGN_ALLOW 1402 config SYSCTL_ARCH_UNALIGN_ALLOW
1512 bool 1403 bool
1513 help 1404 help
1514 Enable support for /proc/sys/kernel 1405 Enable support for /proc/sys/kernel/unaligned-trap
1515 Allows arches to define/use @unalig 1406 Allows arches to define/use @unaligned_enabled to runtime toggle
1516 the unaligned access emulation. 1407 the unaligned access emulation.
1517 see arch/parisc/kernel/unaligned.c 1408 see arch/parisc/kernel/unaligned.c for reference
1518 1409
1519 config HAVE_PCSPKR_PLATFORM 1410 config HAVE_PCSPKR_PLATFORM
1520 bool 1411 bool
1521 1412
>> 1413 # interpreter that classic socket filters depend on
>> 1414 config BPF
>> 1415 bool
>> 1416
1522 menuconfig EXPERT 1417 menuconfig EXPERT
1523 bool "Configure standard kernel featu 1418 bool "Configure standard kernel features (expert users)"
1524 # Unhide debug options, to make the o 1419 # Unhide debug options, to make the on-by-default options visible
1525 select DEBUG_KERNEL 1420 select DEBUG_KERNEL
1526 help 1421 help
1527 This option allows certain base ker 1422 This option allows certain base kernel options and settings
1528 to be disabled or tweaked. This is 1423 to be disabled or tweaked. This is for specialized
1529 environments which can tolerate a " 1424 environments which can tolerate a "non-standard" kernel.
1530 Only use this if you really know wh 1425 Only use this if you really know what you are doing.
1531 1426
1532 config UID16 1427 config UID16
1533 bool "Enable 16-bit UID system calls" 1428 bool "Enable 16-bit UID system calls" if EXPERT
1534 depends on HAVE_UID16 && MULTIUSER 1429 depends on HAVE_UID16 && MULTIUSER
1535 default y 1430 default y
1536 help 1431 help
1537 This enables the legacy 16-bit UID 1432 This enables the legacy 16-bit UID syscall wrappers.
1538 1433
1539 config MULTIUSER 1434 config MULTIUSER
1540 bool "Multiple users, groups and capa 1435 bool "Multiple users, groups and capabilities support" if EXPERT
1541 default y 1436 default y
1542 help 1437 help
1543 This option enables support for non 1438 This option enables support for non-root users, groups and
1544 capabilities. 1439 capabilities.
1545 1440
1546 If you say N here, all processes wi 1441 If you say N here, all processes will run with UID 0, GID 0, and all
1547 possible capabilities. Saying N he 1442 possible capabilities. Saying N here also compiles out support for
1548 system calls related to UIDs, GIDs, 1443 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1549 setgid, and capset. 1444 setgid, and capset.
1550 1445
1551 If unsure, say Y here. 1446 If unsure, say Y here.
1552 1447
1553 config SGETMASK_SYSCALL 1448 config SGETMASK_SYSCALL
1554 bool "sgetmask/ssetmask syscalls supp 1449 bool "sgetmask/ssetmask syscalls support" if EXPERT
1555 default PARISC || M68K || PPC || MIPS !! 1450 def_bool PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH
1556 help 1451 help
1557 sys_sgetmask and sys_ssetmask are o 1452 sys_sgetmask and sys_ssetmask are obsolete system calls
1558 no longer supported in libc but sti 1453 no longer supported in libc but still enabled by default in some
1559 architectures. 1454 architectures.
1560 1455
1561 If unsure, leave the default option 1456 If unsure, leave the default option here.
1562 1457
1563 config SYSFS_SYSCALL 1458 config SYSFS_SYSCALL
1564 bool "Sysfs syscall support" if EXPER 1459 bool "Sysfs syscall support" if EXPERT
1565 default y 1460 default y
1566 help 1461 help
1567 sys_sysfs is an obsolete system cal 1462 sys_sysfs is an obsolete system call no longer supported in libc.
1568 Note that disabling this option is 1463 Note that disabling this option is more secure but might break
1569 compatibility with some systems. 1464 compatibility with some systems.
1570 1465
1571 If unsure say Y here. 1466 If unsure say Y here.
1572 1467
1573 config FHANDLE 1468 config FHANDLE
1574 bool "open by fhandle syscalls" if EX 1469 bool "open by fhandle syscalls" if EXPERT
1575 select EXPORTFS 1470 select EXPORTFS
1576 default y 1471 default y
1577 help 1472 help
1578 If you say Y here, a user level pro 1473 If you say Y here, a user level program will be able to map
1579 file names to handle and then later 1474 file names to handle and then later use the handle for
1580 different file system operations. T 1475 different file system operations. This is useful in implementing
1581 userspace file servers, which now t 1476 userspace file servers, which now track files using handles instead
1582 of names. The handle would remain t 1477 of names. The handle would remain the same even if file names
1583 get renamed. Enables open_by_handle 1478 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
1584 syscalls. 1479 syscalls.
1585 1480
1586 config POSIX_TIMERS 1481 config POSIX_TIMERS
1587 bool "Posix Clocks & timers" if EXPER 1482 bool "Posix Clocks & timers" if EXPERT
1588 default y 1483 default y
1589 help 1484 help
1590 This includes native support for PO 1485 This includes native support for POSIX timers to the kernel.
1591 Some embedded systems have no use f 1486 Some embedded systems have no use for them and therefore they
1592 can be configured out to reduce the 1487 can be configured out to reduce the size of the kernel image.
1593 1488
1594 When this option is disabled, the f 1489 When this option is disabled, the following syscalls won't be
1595 available: timer_create, timer_gett 1490 available: timer_create, timer_gettime: timer_getoverrun,
1596 timer_settime, timer_delete, clock_ 1491 timer_settime, timer_delete, clock_adjtime, getitimer,
1597 setitimer, alarm. Furthermore, the 1492 setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
1598 clock_getres and clock_nanosleep sy 1493 clock_getres and clock_nanosleep syscalls will be limited to
1599 CLOCK_REALTIME, CLOCK_MONOTONIC and 1494 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
1600 1495
1601 If unsure say y. 1496 If unsure say y.
1602 1497
1603 config PRINTK 1498 config PRINTK
1604 default y 1499 default y
1605 bool "Enable support for printk" if E 1500 bool "Enable support for printk" if EXPERT
1606 select IRQ_WORK 1501 select IRQ_WORK
1607 help 1502 help
1608 This option enables normal printk s 1503 This option enables normal printk support. Removing it
1609 eliminates most of the message stri 1504 eliminates most of the message strings from the kernel image
1610 and makes the kernel more or less s 1505 and makes the kernel more or less silent. As this makes it
1611 very difficult to diagnose system p 1506 very difficult to diagnose system problems, saying N here is
1612 strongly discouraged. 1507 strongly discouraged.
1613 1508
>> 1509 config PRINTK_NMI
>> 1510 def_bool y
>> 1511 depends on PRINTK
>> 1512 depends on HAVE_NMI
>> 1513
1614 config BUG 1514 config BUG
1615 bool "BUG() support" if EXPERT 1515 bool "BUG() support" if EXPERT
1616 default y 1516 default y
1617 help 1517 help
1618 Disabling this option eliminates su 1518 Disabling this option eliminates support for BUG and WARN, reducing
1619 the size of your kernel image and p 1519 the size of your kernel image and potentially quietly ignoring
1620 numerous fatal conditions. You shou 1520 numerous fatal conditions. You should only consider disabling this
1621 option for embedded systems with no 1521 option for embedded systems with no facilities for reporting errors.
1622 Just say Y. 1522 Just say Y.
1623 1523
1624 config ELF_CORE 1524 config ELF_CORE
1625 depends on COREDUMP 1525 depends on COREDUMP
1626 default y 1526 default y
1627 bool "Enable ELF core dumps" if EXPER 1527 bool "Enable ELF core dumps" if EXPERT
1628 help 1528 help
1629 Enable support for generating core 1529 Enable support for generating core dumps. Disabling saves about 4k.
1630 1530
1631 1531
1632 config PCSPKR_PLATFORM 1532 config PCSPKR_PLATFORM
1633 bool "Enable PC-Speaker support" if E 1533 bool "Enable PC-Speaker support" if EXPERT
1634 depends on HAVE_PCSPKR_PLATFORM 1534 depends on HAVE_PCSPKR_PLATFORM
1635 select I8253_LOCK 1535 select I8253_LOCK
1636 default y 1536 default y
1637 help 1537 help
1638 This option allows to disable the i 1538 This option allows to disable the internal PC-Speaker
1639 support, saving some memory. 1539 support, saving some memory.
1640 1540
1641 config BASE_SMALL !! 1541 config BASE_FULL
1642 bool "Enable smaller-sized data struc !! 1542 default y
>> 1543 bool "Enable full-sized data structures for core" if EXPERT
1643 help 1544 help
1644 Enabling this option reduces the si !! 1545 Disabling this option reduces the size of miscellaneous core
1645 kernel data structures. This saves 1546 kernel data structures. This saves memory on small machines,
1646 but may reduce performance. 1547 but may reduce performance.
1647 1548
1648 config FUTEX 1549 config FUTEX
1649 bool "Enable futex support" if EXPERT 1550 bool "Enable futex support" if EXPERT
1650 depends on !(SPARC32 && SMP) <<
1651 default y 1551 default y
1652 imply RT_MUTEXES 1552 imply RT_MUTEXES
1653 help 1553 help
1654 Disabling this option will cause th 1554 Disabling this option will cause the kernel to be built without
1655 support for "fast userspace mutexes 1555 support for "fast userspace mutexes". The resulting kernel may not
1656 run glibc-based applications correc 1556 run glibc-based applications correctly.
1657 1557
1658 config FUTEX_PI 1558 config FUTEX_PI
1659 bool 1559 bool
1660 depends on FUTEX && RT_MUTEXES 1560 depends on FUTEX && RT_MUTEXES
1661 default y 1561 default y
1662 1562
>> 1563 config HAVE_FUTEX_CMPXCHG
>> 1564 bool
>> 1565 depends on FUTEX
>> 1566 help
>> 1567 Architectures should select this if futex_atomic_cmpxchg_inatomic()
>> 1568 is implemented and always working. This removes a couple of runtime
>> 1569 checks.
>> 1570
1663 config EPOLL 1571 config EPOLL
1664 bool "Enable eventpoll support" if EX 1572 bool "Enable eventpoll support" if EXPERT
1665 default y 1573 default y
1666 help 1574 help
1667 Disabling this option will cause th 1575 Disabling this option will cause the kernel to be built without
1668 support for epoll family of system 1576 support for epoll family of system calls.
1669 1577
1670 config SIGNALFD 1578 config SIGNALFD
1671 bool "Enable signalfd() system call" 1579 bool "Enable signalfd() system call" if EXPERT
1672 default y 1580 default y
1673 help 1581 help
1674 Enable the signalfd() system call t 1582 Enable the signalfd() system call that allows to receive signals
1675 on a file descriptor. 1583 on a file descriptor.
1676 1584
1677 If unsure, say Y. 1585 If unsure, say Y.
1678 1586
1679 config TIMERFD 1587 config TIMERFD
1680 bool "Enable timerfd() system call" i 1588 bool "Enable timerfd() system call" if EXPERT
1681 default y 1589 default y
1682 help 1590 help
1683 Enable the timerfd() system call th 1591 Enable the timerfd() system call that allows to receive timer
1684 events on a file descriptor. 1592 events on a file descriptor.
1685 1593
1686 If unsure, say Y. 1594 If unsure, say Y.
1687 1595
1688 config EVENTFD 1596 config EVENTFD
1689 bool "Enable eventfd() system call" i 1597 bool "Enable eventfd() system call" if EXPERT
1690 default y 1598 default y
1691 help 1599 help
1692 Enable the eventfd() system call th 1600 Enable the eventfd() system call that allows to receive both
1693 kernel notification (ie. KAIO) or u 1601 kernel notification (ie. KAIO) or userspace notifications.
1694 1602
1695 If unsure, say Y. 1603 If unsure, say Y.
1696 1604
1697 config SHMEM 1605 config SHMEM
1698 bool "Use full shmem filesystem" if E 1606 bool "Use full shmem filesystem" if EXPERT
1699 default y 1607 default y
1700 depends on MMU 1608 depends on MMU
1701 help 1609 help
1702 The shmem is an internal filesystem 1610 The shmem is an internal filesystem used to manage shared memory.
1703 It is backed by swap and manages re 1611 It is backed by swap and manages resource limits. It is also exported
1704 to userspace as tmpfs if TMPFS is e 1612 to userspace as tmpfs if TMPFS is enabled. Disabling this
1705 option replaces shmem and tmpfs wit 1613 option replaces shmem and tmpfs with the much simpler ramfs code,
1706 which may be appropriate on small s 1614 which may be appropriate on small systems without swap.
1707 1615
1708 config AIO 1616 config AIO
1709 bool "Enable AIO support" if EXPERT 1617 bool "Enable AIO support" if EXPERT
1710 default y 1618 default y
1711 help 1619 help
1712 This option enables POSIX asynchron 1620 This option enables POSIX asynchronous I/O which may by used
1713 by some high performance threaded a 1621 by some high performance threaded applications. Disabling
1714 this option saves about 7k. 1622 this option saves about 7k.
1715 1623
1716 config IO_URING 1624 config IO_URING
1717 bool "Enable IO uring support" if EXP 1625 bool "Enable IO uring support" if EXPERT
1718 select IO_WQ 1626 select IO_WQ
1719 default y 1627 default y
1720 help 1628 help
1721 This option enables support for the 1629 This option enables support for the io_uring interface, enabling
1722 applications to submit and complete 1630 applications to submit and complete IO through submission and
1723 completion rings that are shared be 1631 completion rings that are shared between the kernel and application.
1724 1632
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 1633 config ADVISE_SYSCALLS
1739 bool "Enable madvise/fadvise syscalls 1634 bool "Enable madvise/fadvise syscalls" if EXPERT
1740 default y 1635 default y
1741 help 1636 help
1742 This option enables the madvise and 1637 This option enables the madvise and fadvise syscalls, used by
1743 applications to advise the kernel a 1638 applications to advise the kernel about their future memory or file
1744 usage, improving performance. If bu 1639 usage, improving performance. If building an embedded system where no
1745 applications use these syscalls, yo 1640 applications use these syscalls, you can disable this option to save
1746 space. 1641 space.
1747 1642
>> 1643 config HAVE_ARCH_USERFAULTFD_WP
>> 1644 bool
>> 1645 help
>> 1646 Arch has userfaultfd write protection support
>> 1647
>> 1648 config HAVE_ARCH_USERFAULTFD_MINOR
>> 1649 bool
>> 1650 help
>> 1651 Arch has userfaultfd minor fault support
>> 1652
1748 config MEMBARRIER 1653 config MEMBARRIER
1749 bool "Enable membarrier() system call 1654 bool "Enable membarrier() system call" if EXPERT
1750 default y 1655 default y
1751 help 1656 help
1752 Enable the membarrier() system call 1657 Enable the membarrier() system call that allows issuing memory
1753 barriers across all running threads 1658 barriers across all running threads, which can be used to distribute
1754 the cost of user-space memory barri 1659 the cost of user-space memory barriers asymmetrically by transforming
1755 pairs of memory barriers into pairs 1660 pairs of memory barriers into pairs consisting of membarrier() and a
1756 compiler barrier. 1661 compiler barrier.
1757 1662
1758 If unsure, say Y. 1663 If unsure, say Y.
1759 1664
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 1665 config KALLSYMS
1811 bool "Load all symbols for debugging/ 1666 bool "Load all symbols for debugging/ksymoops" if EXPERT
1812 default y 1667 default y
1813 help 1668 help
1814 Say Y here to let the kernel print 1669 Say Y here to let the kernel print out symbolic crash information and
1815 symbolic stack backtraces. This inc 1670 symbolic stack backtraces. This increases the size of the kernel
1816 somewhat, as all symbols have to be 1671 somewhat, as all symbols have to be loaded into the kernel image.
1817 1672
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 1673 config KALLSYMS_ALL
1832 bool "Include all symbols in kallsyms 1674 bool "Include all symbols in kallsyms"
1833 depends on DEBUG_KERNEL && KALLSYMS 1675 depends on DEBUG_KERNEL && KALLSYMS
1834 help 1676 help
1835 Normally kallsyms only contains the 1677 Normally kallsyms only contains the symbols of functions for nicer
1836 OOPS messages and backtraces (i.e., 1678 OOPS messages and backtraces (i.e., symbols from the text and inittext
1837 sections). This is sufficient for m !! 1679 sections). This is sufficient for most cases. And only in very rare
1838 enable kernel live patching, or oth !! 1680 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1839 when a debugger is used) all symbol !! 1681 names of variables from the data sections, etc).
1840 variables from the data sections, e <<
1841 1682
1842 This option makes sure that all sym 1683 This option makes sure that all symbols are loaded into the kernel
1843 image (i.e., symbols from all secti 1684 image (i.e., symbols from all sections) in cost of increased kernel
1844 size (depending on the kernel confi 1685 size (depending on the kernel configuration, it may be 300KiB or
1845 something like this). 1686 something like this).
1846 1687
1847 Say N unless you really need all sy !! 1688 Say N unless you really need all symbols.
1848 1689
1849 config KALLSYMS_ABSOLUTE_PERCPU 1690 config KALLSYMS_ABSOLUTE_PERCPU
1850 bool 1691 bool
1851 depends on KALLSYMS 1692 depends on KALLSYMS
1852 default X86_64 && SMP 1693 default X86_64 && SMP
1853 1694
>> 1695 config KALLSYMS_BASE_RELATIVE
>> 1696 bool
>> 1697 depends on KALLSYMS
>> 1698 default !IA64
>> 1699 help
>> 1700 Instead of emitting them as absolute values in the native word size,
>> 1701 emit the symbol references in the kallsyms table as 32-bit entries,
>> 1702 each containing a relative value in the range [base, base + U32_MAX]
>> 1703 or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either
>> 1704 an absolute value in the range [0, S32_MAX] or a relative value in the
>> 1705 range [base, base + S32_MAX], where base is the lowest relative symbol
>> 1706 address encountered in the image.
>> 1707
>> 1708 On 64-bit builds, this reduces the size of the address table by 50%,
>> 1709 but more importantly, it results in entries whose values are build
>> 1710 time constants, and no relocation pass is required at runtime to fix
>> 1711 up the entries based on the runtime load address of the kernel.
>> 1712
1854 # end of the "standard kernel features (exper 1713 # end of the "standard kernel features (expert users)" menu
1855 1714
>> 1715 # syscall, maps, verifier
>> 1716
>> 1717 config USERFAULTFD
>> 1718 bool "Enable userfaultfd() system call"
>> 1719 depends on MMU
>> 1720 help
>> 1721 Enable the userfaultfd() system call that allows to intercept and
>> 1722 handle page faults in userland.
>> 1723
1856 config ARCH_HAS_MEMBARRIER_CALLBACKS 1724 config ARCH_HAS_MEMBARRIER_CALLBACKS
1857 bool 1725 bool
1858 1726
1859 config ARCH_HAS_MEMBARRIER_SYNC_CORE 1727 config ARCH_HAS_MEMBARRIER_SYNC_CORE
1860 bool 1728 bool
1861 1729
>> 1730 config KCMP
>> 1731 bool "Enable kcmp() system call" if EXPERT
>> 1732 help
>> 1733 Enable the kernel resource comparison system call. It provides
>> 1734 user-space with the ability to compare two processes to see if they
>> 1735 share a common resource, such as a file descriptor or even virtual
>> 1736 memory space.
>> 1737
>> 1738 If unsure, say N.
>> 1739
>> 1740 config RSEQ
>> 1741 bool "Enable rseq() system call" if EXPERT
>> 1742 default y
>> 1743 depends on HAVE_RSEQ
>> 1744 select MEMBARRIER
>> 1745 help
>> 1746 Enable the restartable sequences system call. It provides a
>> 1747 user-space cache for the current CPU number value, which
>> 1748 speeds up getting the current CPU number from user-space,
>> 1749 as well as an ABI to speed up user-space operations on
>> 1750 per-CPU data.
>> 1751
>> 1752 If unsure, say Y.
>> 1753
>> 1754 config DEBUG_RSEQ
>> 1755 default n
>> 1756 bool "Enabled debugging of rseq() system call" if EXPERT
>> 1757 depends on RSEQ && DEBUG_KERNEL
>> 1758 help
>> 1759 Enable extra debugging checks for the rseq system call.
>> 1760
>> 1761 If unsure, say N.
>> 1762
>> 1763 config EMBEDDED
>> 1764 bool "Embedded system"
>> 1765 select EXPERT
>> 1766 help
>> 1767 This option should be enabled if compiling the kernel for
>> 1768 an embedded system so certain expert options are available
>> 1769 for configuration.
>> 1770
1862 config HAVE_PERF_EVENTS 1771 config HAVE_PERF_EVENTS
1863 bool 1772 bool
1864 help 1773 help
1865 See tools/perf/design.txt for detai 1774 See tools/perf/design.txt for details.
1866 1775
1867 config GUEST_PERF_EVENTS <<
1868 bool <<
1869 depends on HAVE_PERF_EVENTS <<
1870 <<
1871 config PERF_USE_VMALLOC 1776 config PERF_USE_VMALLOC
1872 bool 1777 bool
1873 help 1778 help
1874 See tools/perf/design.txt for detai 1779 See tools/perf/design.txt for details
1875 1780
>> 1781 config PC104
>> 1782 bool "PC/104 support" if EXPERT
>> 1783 help
>> 1784 Expose PC/104 form factor device drivers and options available for
>> 1785 selection and configuration. Enable this option if your target
>> 1786 machine has a PC/104 bus.
>> 1787
1876 menu "Kernel Performance Events And Counters" 1788 menu "Kernel Performance Events And Counters"
1877 1789
1878 config PERF_EVENTS 1790 config PERF_EVENTS
1879 bool "Kernel performance events and c 1791 bool "Kernel performance events and counters"
1880 default y if PROFILING 1792 default y if PROFILING
1881 depends on HAVE_PERF_EVENTS 1793 depends on HAVE_PERF_EVENTS
1882 select IRQ_WORK 1794 select IRQ_WORK
>> 1795 select SRCU
1883 help 1796 help
1884 Enable kernel support for various p 1797 Enable kernel support for various performance events provided
1885 by software and hardware. 1798 by software and hardware.
1886 1799
1887 Software events are supported eithe 1800 Software events are supported either built-in or via the
1888 use of generic tracepoints. 1801 use of generic tracepoints.
1889 1802
1890 Most modern CPUs support performanc 1803 Most modern CPUs support performance events via performance
1891 counter registers. These registers 1804 counter registers. These registers count the number of certain
1892 types of hw events: such as instruc 1805 types of hw events: such as instructions executed, cachemisses
1893 suffered, or branches mis-predicted 1806 suffered, or branches mis-predicted - without slowing down the
1894 kernel or applications. These regis 1807 kernel or applications. These registers can also trigger interrupts
1895 when a threshold number of events h 1808 when a threshold number of events have passed - and can thus be
1896 used to profile the code that runs 1809 used to profile the code that runs on that CPU.
1897 1810
1898 The Linux Performance Event subsyst 1811 The Linux Performance Event subsystem provides an abstraction of
1899 these software and hardware event c 1812 these software and hardware event capabilities, available via a
1900 system call and used by the "perf" 1813 system call and used by the "perf" utility in tools/perf/. It
1901 provides per task and per CPU count 1814 provides per task and per CPU counters, and it provides event
1902 capabilities on top of those. 1815 capabilities on top of those.
1903 1816
1904 Say Y if unsure. 1817 Say Y if unsure.
1905 1818
1906 config DEBUG_PERF_USE_VMALLOC 1819 config DEBUG_PERF_USE_VMALLOC
1907 default n 1820 default n
1908 bool "Debug: use vmalloc to back perf 1821 bool "Debug: use vmalloc to back perf mmap() buffers"
1909 depends on PERF_EVENTS && DEBUG_KERNE 1822 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
1910 select PERF_USE_VMALLOC 1823 select PERF_USE_VMALLOC
1911 help 1824 help
1912 Use vmalloc memory to back perf mma 1825 Use vmalloc memory to back perf mmap() buffers.
1913 1826
1914 Mostly useful for debugging the vma 1827 Mostly useful for debugging the vmalloc code on platforms
1915 that don't require it. 1828 that don't require it.
1916 1829
1917 Say N if unsure. 1830 Say N if unsure.
1918 1831
1919 endmenu 1832 endmenu
1920 1833
>> 1834 config VM_EVENT_COUNTERS
>> 1835 default y
>> 1836 bool "Enable VM event counters for /proc/vmstat" if EXPERT
>> 1837 help
>> 1838 VM event counters are needed for event counts to be shown.
>> 1839 This option allows the disabling of the VM event counters
>> 1840 on EXPERT systems. /proc/vmstat will only show page counts
>> 1841 if VM event counters are disabled.
>> 1842
>> 1843 config SLUB_DEBUG
>> 1844 default y
>> 1845 bool "Enable SLUB debugging support" if EXPERT
>> 1846 depends on SLUB && SYSFS
>> 1847 help
>> 1848 SLUB has extensive debug support features. Disabling these can
>> 1849 result in significant savings in code size. This also disables
>> 1850 SLUB sysfs support. /sys/slab will not exist and there will be
>> 1851 no support for cache validation etc.
>> 1852
>> 1853 config COMPAT_BRK
>> 1854 bool "Disable heap randomization"
>> 1855 default y
>> 1856 help
>> 1857 Randomizing heap placement makes heap exploits harder, but it
>> 1858 also breaks ancient binaries (including anything libc5 based).
>> 1859 This option changes the bootup default to heap randomization
>> 1860 disabled, and can be overridden at runtime by setting
>> 1861 /proc/sys/kernel/randomize_va_space to 2.
>> 1862
>> 1863 On non-ancient distros (post-2000 ones) N is usually a safe choice.
>> 1864
>> 1865 choice
>> 1866 prompt "Choose SLAB allocator"
>> 1867 default SLUB
>> 1868 help
>> 1869 This option allows to select a slab allocator.
>> 1870
>> 1871 config SLAB
>> 1872 bool "SLAB"
>> 1873 select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 1874 help
>> 1875 The regular slab allocator that is established and known to work
>> 1876 well in all environments. It organizes cache hot objects in
>> 1877 per cpu and per node queues.
>> 1878
>> 1879 config SLUB
>> 1880 bool "SLUB (Unqueued Allocator)"
>> 1881 select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 1882 help
>> 1883 SLUB is a slab allocator that minimizes cache line usage
>> 1884 instead of managing queues of cached objects (SLAB approach).
>> 1885 Per cpu caching is realized using slabs of objects instead
>> 1886 of queues of objects. SLUB can use memory efficiently
>> 1887 and has enhanced diagnostics. SLUB is the default choice for
>> 1888 a slab allocator.
>> 1889
>> 1890 config SLOB
>> 1891 depends on EXPERT
>> 1892 bool "SLOB (Simple Allocator)"
>> 1893 help
>> 1894 SLOB replaces the stock allocator with a drastically simpler
>> 1895 allocator. SLOB is generally more space efficient but
>> 1896 does not perform as well on large systems.
>> 1897
>> 1898 endchoice
>> 1899
>> 1900 config SLAB_MERGE_DEFAULT
>> 1901 bool "Allow slab caches to be merged"
>> 1902 default y
>> 1903 help
>> 1904 For reduced kernel memory fragmentation, slab caches can be
>> 1905 merged when they share the same size and other characteristics.
>> 1906 This carries a risk of kernel heap overflows being able to
>> 1907 overwrite objects from merged caches (and more easily control
>> 1908 cache layout), which makes such heap attacks easier to exploit
>> 1909 by attackers. By keeping caches unmerged, these kinds of exploits
>> 1910 can usually only damage objects in the same cache. To disable
>> 1911 merging at runtime, "slab_nomerge" can be passed on the kernel
>> 1912 command line.
>> 1913
>> 1914 config SLAB_FREELIST_RANDOM
>> 1915 bool "Randomize slab freelist"
>> 1916 depends on SLAB || SLUB
>> 1917 help
>> 1918 Randomizes the freelist order used on creating new pages. This
>> 1919 security feature reduces the predictability of the kernel slab
>> 1920 allocator against heap overflows.
>> 1921
>> 1922 config SLAB_FREELIST_HARDENED
>> 1923 bool "Harden slab freelist metadata"
>> 1924 depends on SLAB || SLUB
>> 1925 help
>> 1926 Many kernel heap attacks try to target slab cache metadata and
>> 1927 other infrastructure. This options makes minor performance
>> 1928 sacrifices to harden the kernel slab allocator against common
>> 1929 freelist exploit methods. Some slab implementations have more
>> 1930 sanity-checking than others. This option is most effective with
>> 1931 CONFIG_SLUB.
>> 1932
>> 1933 config SHUFFLE_PAGE_ALLOCATOR
>> 1934 bool "Page allocator randomization"
>> 1935 default SLAB_FREELIST_RANDOM && ACPI_NUMA
>> 1936 help
>> 1937 Randomization of the page allocator improves the average
>> 1938 utilization of a direct-mapped memory-side-cache. See section
>> 1939 5.2.27 Heterogeneous Memory Attribute Table (HMAT) in the ACPI
>> 1940 6.2a specification for an example of how a platform advertises
>> 1941 the presence of a memory-side-cache. There are also incidental
>> 1942 security benefits as it reduces the predictability of page
>> 1943 allocations to compliment SLAB_FREELIST_RANDOM, but the
>> 1944 default granularity of shuffling on the "MAX_ORDER - 1" i.e,
>> 1945 10th order of pages is selected based on cache utilization
>> 1946 benefits on x86.
>> 1947
>> 1948 While the randomization improves cache utilization it may
>> 1949 negatively impact workloads on platforms without a cache. For
>> 1950 this reason, by default, the randomization is enabled only
>> 1951 after runtime detection of a direct-mapped memory-side-cache.
>> 1952 Otherwise, the randomization may be force enabled with the
>> 1953 'page_alloc.shuffle' kernel command line parameter.
>> 1954
>> 1955 Say Y if unsure.
>> 1956
>> 1957 config SLUB_CPU_PARTIAL
>> 1958 default y
>> 1959 depends on SLUB && SMP
>> 1960 bool "SLUB per cpu partial cache"
>> 1961 help
>> 1962 Per cpu partial caches accelerate objects allocation and freeing
>> 1963 that is local to a processor at the price of more indeterminism
>> 1964 in the latency of the free. On overflow these caches will be cleared
>> 1965 which requires the taking of locks that may cause latency spikes.
>> 1966 Typically one would choose no for a realtime system.
>> 1967
>> 1968 config MMAP_ALLOW_UNINITIALIZED
>> 1969 bool "Allow mmapped anonymous memory to be uninitialized"
>> 1970 depends on EXPERT && !MMU
>> 1971 default n
>> 1972 help
>> 1973 Normally, and according to the Linux spec, anonymous memory obtained
>> 1974 from mmap() has its contents cleared before it is passed to
>> 1975 userspace. Enabling this config option allows you to request that
>> 1976 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
>> 1977 providing a huge performance boost. If this option is not enabled,
>> 1978 then the flag will be ignored.
>> 1979
>> 1980 This is taken advantage of by uClibc's malloc(), and also by
>> 1981 ELF-FDPIC binfmt's brk and stack allocator.
>> 1982
>> 1983 Because of the obvious security issues, this option should only be
>> 1984 enabled on embedded devices where you control what is run in
>> 1985 userspace. Since that isn't generally a problem on no-MMU systems,
>> 1986 it is normally safe to say Y here.
>> 1987
>> 1988 See Documentation/admin-guide/mm/nommu-mmap.rst for more information.
>> 1989
1921 config SYSTEM_DATA_VERIFICATION 1990 config SYSTEM_DATA_VERIFICATION
1922 def_bool n 1991 def_bool n
1923 select SYSTEM_TRUSTED_KEYRING 1992 select SYSTEM_TRUSTED_KEYRING
1924 select KEYS 1993 select KEYS
1925 select CRYPTO 1994 select CRYPTO
1926 select CRYPTO_RSA 1995 select CRYPTO_RSA
1927 select ASYMMETRIC_KEY_TYPE 1996 select ASYMMETRIC_KEY_TYPE
1928 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 1997 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1929 select ASN1 1998 select ASN1
1930 select OID_REGISTRY 1999 select OID_REGISTRY
1931 select X509_CERTIFICATE_PARSER 2000 select X509_CERTIFICATE_PARSER
1932 select PKCS7_MESSAGE_PARSER 2001 select PKCS7_MESSAGE_PARSER
1933 help 2002 help
1934 Provide PKCS#7 message verification 2003 Provide PKCS#7 message verification using the contents of the system
1935 trusted keyring to provide public k 2004 trusted keyring to provide public keys. This then can be used for
1936 module verification, kexec image ve 2005 module verification, kexec image verification and firmware blob
1937 verification. 2006 verification.
1938 2007
1939 config PROFILING 2008 config PROFILING
1940 bool "Profiling support" 2009 bool "Profiling support"
1941 help 2010 help
1942 Say Y here to enable the extended p 2011 Say Y here to enable the extended profiling support mechanisms used
1943 by profilers. 2012 by profilers.
1944 2013
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 # 2014 #
1987 # Place an empty function call at each tracep 2015 # Place an empty function call at each tracepoint site. Can be
1988 # dynamically changed for a probe function. 2016 # dynamically changed for a probe function.
1989 # 2017 #
1990 config TRACEPOINTS 2018 config TRACEPOINTS
1991 bool 2019 bool
1992 2020
1993 source "kernel/Kconfig.kexec" <<
1994 <<
1995 endmenu # General setup 2021 endmenu # General setup
1996 2022
1997 source "arch/Kconfig" 2023 source "arch/Kconfig"
1998 2024
1999 config RT_MUTEXES 2025 config RT_MUTEXES
2000 bool 2026 bool
2001 default y if PREEMPT_RT !! 2027
>> 2028 config BASE_SMALL
>> 2029 int
>> 2030 default 0 if BASE_FULL
>> 2031 default 1 if !BASE_FULL
2002 2032
2003 config MODULE_SIG_FORMAT 2033 config MODULE_SIG_FORMAT
2004 def_bool n 2034 def_bool n
2005 select SYSTEM_DATA_VERIFICATION 2035 select SYSTEM_DATA_VERIFICATION
2006 2036
2007 source "kernel/module/Kconfig" !! 2037 menuconfig MODULES
>> 2038 bool "Enable loadable module support"
>> 2039 modules
>> 2040 help
>> 2041 Kernel modules are small pieces of compiled code which can
>> 2042 be inserted in the running kernel, rather than being
>> 2043 permanently built into the kernel. You use the "modprobe"
>> 2044 tool to add (and sometimes remove) them. If you say Y here,
>> 2045 many parts of the kernel can be built as modules (by
>> 2046 answering M instead of Y where indicated): this is most
>> 2047 useful for infrequently used options which are not required
>> 2048 for booting. For more information, see the man pages for
>> 2049 modprobe, lsmod, modinfo, insmod and rmmod.
>> 2050
>> 2051 If you say Y here, you will need to run "make
>> 2052 modules_install" to put the modules under /lib/modules/
>> 2053 where modprobe can find them (you may need to be root to do
>> 2054 this).
>> 2055
>> 2056 If unsure, say Y.
>> 2057
>> 2058 if MODULES
>> 2059
>> 2060 config MODULE_FORCE_LOAD
>> 2061 bool "Forced module loading"
>> 2062 default n
>> 2063 help
>> 2064 Allow loading of modules without version information (ie. modprobe
>> 2065 --force). Forced module loading sets the 'F' (forced) taint flag and
>> 2066 is usually a really bad idea.
>> 2067
>> 2068 config MODULE_UNLOAD
>> 2069 bool "Module unloading"
>> 2070 help
>> 2071 Without this option you will not be able to unload any
>> 2072 modules (note that some modules may not be unloadable
>> 2073 anyway), which makes your kernel smaller, faster
>> 2074 and simpler. If unsure, say Y.
>> 2075
>> 2076 config MODULE_FORCE_UNLOAD
>> 2077 bool "Forced module unloading"
>> 2078 depends on MODULE_UNLOAD
>> 2079 help
>> 2080 This option allows you to force a module to unload, even if the
>> 2081 kernel believes it is unsafe: the kernel will remove the module
>> 2082 without waiting for anyone to stop using it (using the -f option to
>> 2083 rmmod). This is mainly for kernel developers and desperate users.
>> 2084 If unsure, say N.
>> 2085
>> 2086 config MODVERSIONS
>> 2087 bool "Module versioning support"
>> 2088 help
>> 2089 Usually, you have to use modules compiled with your kernel.
>> 2090 Saying Y here makes it sometimes possible to use modules
>> 2091 compiled for different kernels, by adding enough information
>> 2092 to the modules to (hopefully) spot any changes which would
>> 2093 make them incompatible with the kernel you are running. If
>> 2094 unsure, say N.
>> 2095
>> 2096 config ASM_MODVERSIONS
>> 2097 bool
>> 2098 default HAVE_ASM_MODVERSIONS && MODVERSIONS
>> 2099 help
>> 2100 This enables module versioning for exported symbols also from
>> 2101 assembly. This can be enabled only when the target architecture
>> 2102 supports it.
>> 2103
>> 2104 config MODULE_REL_CRCS
>> 2105 bool
>> 2106 depends on MODVERSIONS
>> 2107
>> 2108 config MODULE_SRCVERSION_ALL
>> 2109 bool "Source checksum for all modules"
>> 2110 help
>> 2111 Modules which contain a MODULE_VERSION get an extra "srcversion"
>> 2112 field inserted into their modinfo section, which contains a
>> 2113 sum of the source files which made it. This helps maintainers
>> 2114 see exactly which source was used to build a module (since
>> 2115 others sometimes change the module source without updating
>> 2116 the version). With this option, such a "srcversion" field
>> 2117 will be created for all modules. If unsure, say N.
>> 2118
>> 2119 config MODULE_SIG
>> 2120 bool "Module signature verification"
>> 2121 select MODULE_SIG_FORMAT
>> 2122 help
>> 2123 Check modules for valid signatures upon load: the signature
>> 2124 is simply appended to the module. For more information see
>> 2125 <file:Documentation/admin-guide/module-signing.rst>.
>> 2126
>> 2127 Note that this option adds the OpenSSL development packages as a
>> 2128 kernel build dependency so that the signing tool can use its crypto
>> 2129 library.
>> 2130
>> 2131 You should enable this option if you wish to use either
>> 2132 CONFIG_SECURITY_LOCKDOWN_LSM or lockdown functionality imposed via
>> 2133 another LSM - otherwise unsigned modules will be loadable regardless
>> 2134 of the lockdown policy.
>> 2135
>> 2136 !!!WARNING!!! If you enable this option, you MUST make sure that the
>> 2137 module DOES NOT get stripped after being signed. This includes the
>> 2138 debuginfo strip done by some packagers (such as rpmbuild) and
>> 2139 inclusion into an initramfs that wants the module size reduced.
>> 2140
>> 2141 config MODULE_SIG_FORCE
>> 2142 bool "Require modules to be validly signed"
>> 2143 depends on MODULE_SIG
>> 2144 help
>> 2145 Reject unsigned modules or signed modules for which we don't have a
>> 2146 key. Without this, such modules will simply taint the kernel.
>> 2147
>> 2148 config MODULE_SIG_ALL
>> 2149 bool "Automatically sign all modules"
>> 2150 default y
>> 2151 depends on MODULE_SIG || IMA_APPRAISE_MODSIG
>> 2152 help
>> 2153 Sign all modules during make modules_install. Without this option,
>> 2154 modules must be signed manually, using the scripts/sign-file tool.
>> 2155
>> 2156 comment "Do not forget to sign required modules with scripts/sign-file"
>> 2157 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
>> 2158
>> 2159 choice
>> 2160 prompt "Which hash algorithm should modules be signed with?"
>> 2161 depends on MODULE_SIG || IMA_APPRAISE_MODSIG
>> 2162 help
>> 2163 This determines which sort of hashing algorithm will be used during
>> 2164 signature generation. This algorithm _must_ be built into the kernel
>> 2165 directly so that signature verification can take place. It is not
>> 2166 possible to load a signed module containing the algorithm to check
>> 2167 the signature on that module.
>> 2168
>> 2169 config MODULE_SIG_SHA1
>> 2170 bool "Sign modules with SHA-1"
>> 2171 select CRYPTO_SHA1
>> 2172
>> 2173 config MODULE_SIG_SHA224
>> 2174 bool "Sign modules with SHA-224"
>> 2175 select CRYPTO_SHA256
>> 2176
>> 2177 config MODULE_SIG_SHA256
>> 2178 bool "Sign modules with SHA-256"
>> 2179 select CRYPTO_SHA256
>> 2180
>> 2181 config MODULE_SIG_SHA384
>> 2182 bool "Sign modules with SHA-384"
>> 2183 select CRYPTO_SHA512
>> 2184
>> 2185 config MODULE_SIG_SHA512
>> 2186 bool "Sign modules with SHA-512"
>> 2187 select CRYPTO_SHA512
>> 2188
>> 2189 endchoice
>> 2190
>> 2191 config MODULE_SIG_HASH
>> 2192 string
>> 2193 depends on MODULE_SIG || IMA_APPRAISE_MODSIG
>> 2194 default "sha1" if MODULE_SIG_SHA1
>> 2195 default "sha224" if MODULE_SIG_SHA224
>> 2196 default "sha256" if MODULE_SIG_SHA256
>> 2197 default "sha384" if MODULE_SIG_SHA384
>> 2198 default "sha512" if MODULE_SIG_SHA512
>> 2199
>> 2200 choice
>> 2201 prompt "Module compression mode"
>> 2202 help
>> 2203 This option allows you to choose the algorithm which will be used to
>> 2204 compress modules when 'make modules_install' is run. (or, you can
>> 2205 choose to not compress modules at all.)
>> 2206
>> 2207 External modules will also be compressed in the same way during the
>> 2208 installation.
>> 2209
>> 2210 For modules inside an initrd or initramfs, it's more efficient to
>> 2211 compress the whole initrd or initramfs instead.
>> 2212
>> 2213 This is fully compatible with signed modules.
>> 2214
>> 2215 Please note that the tool used to load modules needs to support the
>> 2216 corresponding algorithm. module-init-tools MAY support gzip, and kmod
>> 2217 MAY support gzip, xz and zstd.
>> 2218
>> 2219 Your build system needs to provide the appropriate compression tool
>> 2220 to compress the modules.
>> 2221
>> 2222 If in doubt, select 'None'.
>> 2223
>> 2224 config MODULE_COMPRESS_NONE
>> 2225 bool "None"
>> 2226 help
>> 2227 Do not compress modules. The installed modules are suffixed
>> 2228 with .ko.
>> 2229
>> 2230 config MODULE_COMPRESS_GZIP
>> 2231 bool "GZIP"
>> 2232 help
>> 2233 Compress modules with GZIP. The installed modules are suffixed
>> 2234 with .ko.gz.
>> 2235
>> 2236 config MODULE_COMPRESS_XZ
>> 2237 bool "XZ"
>> 2238 help
>> 2239 Compress modules with XZ. The installed modules are suffixed
>> 2240 with .ko.xz.
>> 2241
>> 2242 config MODULE_COMPRESS_ZSTD
>> 2243 bool "ZSTD"
>> 2244 help
>> 2245 Compress modules with ZSTD. The installed modules are suffixed
>> 2246 with .ko.zst.
>> 2247
>> 2248 endchoice
>> 2249
>> 2250 config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
>> 2251 bool "Allow loading of modules with missing namespace imports"
>> 2252 help
>> 2253 Symbols exported with EXPORT_SYMBOL_NS*() are considered exported in
>> 2254 a namespace. A module that makes use of a symbol exported with such a
>> 2255 namespace is required to import the namespace via MODULE_IMPORT_NS().
>> 2256 There is no technical reason to enforce correct namespace imports,
>> 2257 but it creates consistency between symbols defining namespaces and
>> 2258 users importing namespaces they make use of. This option relaxes this
>> 2259 requirement and lifts the enforcement when loading a module.
>> 2260
>> 2261 If unsure, say N.
>> 2262
>> 2263 config MODPROBE_PATH
>> 2264 string "Path to modprobe binary"
>> 2265 default "/sbin/modprobe"
>> 2266 help
>> 2267 When kernel code requests a module, it does so by calling
>> 2268 the "modprobe" userspace utility. This option allows you to
>> 2269 set the path where that binary is found. This can be changed
>> 2270 at runtime via the sysctl file
>> 2271 /proc/sys/kernel/modprobe. Setting this to the empty string
>> 2272 removes the kernel's ability to request modules (but
>> 2273 userspace can still load modules explicitly).
>> 2274
>> 2275 config TRIM_UNUSED_KSYMS
>> 2276 bool "Trim unused exported kernel symbols" if EXPERT
>> 2277 depends on !COMPILE_TEST
>> 2278 help
>> 2279 The kernel and some modules make many symbols available for
>> 2280 other modules to use via EXPORT_SYMBOL() and variants. Depending
>> 2281 on the set of modules being selected in your kernel configuration,
>> 2282 many of those exported symbols might never be used.
>> 2283
>> 2284 This option allows for unused exported symbols to be dropped from
>> 2285 the build. In turn, this provides the compiler more opportunities
>> 2286 (especially when using LTO) for optimizing the code and reducing
>> 2287 binary size. This might have some security advantages as well.
>> 2288
>> 2289 If unsure, or if you need to build out-of-tree modules, say N.
>> 2290
>> 2291 config UNUSED_KSYMS_WHITELIST
>> 2292 string "Whitelist of symbols to keep in ksymtab"
>> 2293 depends on TRIM_UNUSED_KSYMS
>> 2294 help
>> 2295 By default, all unused exported symbols will be un-exported from the
>> 2296 build when TRIM_UNUSED_KSYMS is selected.
>> 2297
>> 2298 UNUSED_KSYMS_WHITELIST allows to whitelist symbols that must be kept
>> 2299 exported at all times, even in absence of in-tree users. The value to
>> 2300 set here is the path to a text file containing the list of symbols,
>> 2301 one per line. The path can be absolute, or relative to the kernel
>> 2302 source tree.
>> 2303
>> 2304 endif # MODULES
>> 2305
>> 2306 config MODULES_TREE_LOOKUP
>> 2307 def_bool y
>> 2308 depends on PERF_EVENTS || TRACING || CFI_CLANG
2008 2309
2009 config INIT_ALL_POSSIBLE 2310 config INIT_ALL_POSSIBLE
2010 bool 2311 bool
2011 help 2312 help
2012 Back when each arch used to define 2313 Back when each arch used to define their own cpu_online_mask and
2013 cpu_possible_mask, some of them cho 2314 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
2014 with all 1s, and others with all 0s 2315 with all 1s, and others with all 0s. When they were centralised,
2015 it was better to provide this optio 2316 it was better to provide this option than to break all the archs
2016 and have several arch maintainers p 2317 and have several arch maintainers pursuing me down dark alleys.
2017 2318
2018 source "block/Kconfig" 2319 source "block/Kconfig"
2019 2320
2020 config PREEMPT_NOTIFIERS 2321 config PREEMPT_NOTIFIERS
2021 bool 2322 bool
2022 2323
2023 config PADATA 2324 config PADATA
2024 depends on SMP 2325 depends on SMP
2025 bool 2326 bool
2026 2327
2027 config ASN1 2328 config ASN1
2028 tristate 2329 tristate
2029 help 2330 help
2030 Build a simple ASN.1 grammar compil 2331 Build a simple ASN.1 grammar compiler that produces a bytecode output
2031 that can be interpreted by the ASN. 2332 that can be interpreted by the ASN.1 stream decoder and used to
2032 inform it as to what tags are to be 2333 inform it as to what tags are to be expected in a stream and what
2033 functions to call on what tags. 2334 functions to call on what tags.
2034 2335
2035 source "kernel/Kconfig.locks" 2336 source "kernel/Kconfig.locks"
2036 2337
2037 config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 2338 config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
2038 bool <<
2039 <<
2040 config ARCH_HAS_PREPARE_SYNC_CORE_CMD <<
2041 bool 2339 bool
2042 2340
2043 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2341 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
2044 bool 2342 bool
2045 2343
2046 # It may be useful for an architecture to ove 2344 # It may be useful for an architecture to override the definitions of the
2047 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() ma 2345 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h>
2048 # and the COMPAT_ variants in <linux/compat.h 2346 # and the COMPAT_ variants in <linux/compat.h>, in particular to use a
2049 # different calling convention for syscalls. 2347 # different calling convention for syscalls. They can also override the
2050 # macros for not-implemented syscalls in kern 2348 # macros for not-implemented syscalls in kernel/sys_ni.c and
2051 # kernel/time/posix-stubs.c. All these overri 2349 # kernel/time/posix-stubs.c. All these overrides need to be available in
2052 # <asm/syscall_wrapper.h>. 2350 # <asm/syscall_wrapper.h>.
2053 config ARCH_HAS_SYSCALL_WRAPPER 2351 config ARCH_HAS_SYSCALL_WRAPPER
2054 def_bool n 2352 def_bool n
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