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 86 config CC_HAS_NO_PROFILE_FN_ATTR
121 def_bool $(success,echo '__attribute__ 87 def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror)
122 88
123 config PAHOLE_VERSION <<
124 int <<
125 default $(shell,$(srctree)/scripts/pah <<
126 <<
127 config CONSTRUCTORS 89 config CONSTRUCTORS
128 bool 90 bool
129 91
130 config IRQ_WORK 92 config IRQ_WORK
131 def_bool y if SMP !! 93 bool
132 94
133 config BUILDTIME_TABLE_SORT 95 config BUILDTIME_TABLE_SORT
134 bool 96 bool
135 97
136 config THREAD_INFO_IN_TASK 98 config THREAD_INFO_IN_TASK
137 bool 99 bool
138 help 100 help
139 Select this to move thread_info off 101 Select this to move thread_info off the stack into task_struct. To
140 make this work, an arch will need to 102 make this work, an arch will need to remove all thread_info fields
141 except flags and fix any runtime bug 103 except flags and fix any runtime bugs.
142 104
143 One subtle change that will be neede 105 One subtle change that will be needed is to use try_get_task_stack()
144 and put_task_stack() in save_thread_ 106 and put_task_stack() in save_thread_stack_tsk() and get_wchan().
145 107
146 menu "General setup" 108 menu "General setup"
147 109
148 config BROKEN 110 config BROKEN
149 bool 111 bool
150 112
151 config BROKEN_ON_SMP 113 config BROKEN_ON_SMP
152 bool 114 bool
153 depends on BROKEN || !SMP 115 depends on BROKEN || !SMP
154 default y 116 default y
155 117
156 config INIT_ENV_ARG_LIMIT 118 config INIT_ENV_ARG_LIMIT
157 int 119 int
158 default 32 if !UML 120 default 32 if !UML
159 default 128 if UML 121 default 128 if UML
160 help 122 help
161 Maximum of each of the number of arg 123 Maximum of each of the number of arguments and environment
162 variables passed to init from the ke 124 variables passed to init from the kernel command line.
163 125
164 config COMPILE_TEST 126 config COMPILE_TEST
165 bool "Compile also drivers which will 127 bool "Compile also drivers which will not load"
166 depends on HAS_IOMEM 128 depends on HAS_IOMEM
167 help 129 help
168 Some drivers can be compiled on a di 130 Some drivers can be compiled on a different platform than they are
169 intended to be run on. Despite they 131 intended to be run on. Despite they cannot be loaded there (or even
170 when they load they cannot be used d 132 when they load they cannot be used due to missing HW support),
171 developers still, opposing to distri 133 developers still, opposing to distributors, might want to build such
172 drivers to compile-test them. 134 drivers to compile-test them.
173 135
174 If you are a developer and want to b 136 If you are a developer and want to build everything available, say Y
175 here. If you are a user/distributor, 137 here. If you are a user/distributor, say N here to exclude useless
176 drivers to be distributed. 138 drivers to be distributed.
177 139
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 140 config UAPI_HEADER_TEST
196 bool "Compile test UAPI headers" 141 bool "Compile test UAPI headers"
197 depends on HEADERS_INSTALL && CC_CAN_L 142 depends on HEADERS_INSTALL && CC_CAN_LINK
198 help 143 help
199 Compile test headers exported to use 144 Compile test headers exported to user-space to ensure they are
200 self-contained, i.e. compilable as s 145 self-contained, i.e. compilable as standalone units.
201 146
202 If you are a developer or tester and 147 If you are a developer or tester and want to ensure the exported
203 headers are self-contained, say Y he 148 headers are self-contained, say Y here. Otherwise, choose N.
204 149
205 config LOCALVERSION 150 config LOCALVERSION
206 string "Local version - append to kern 151 string "Local version - append to kernel release"
207 help 152 help
208 Append an extra string to the end of 153 Append an extra string to the end of your kernel version.
209 This will show up when you type unam 154 This will show up when you type uname, for example.
210 The string you set here will be appe 155 The string you set here will be appended after the contents of
211 any files with a filename matching l 156 any files with a filename matching localversion* in your
212 object and source tree, in that orde 157 object and source tree, in that order. Your total string can
213 be a maximum of 64 characters. 158 be a maximum of 64 characters.
214 159
215 config LOCALVERSION_AUTO 160 config LOCALVERSION_AUTO
216 bool "Automatically append version inf 161 bool "Automatically append version information to the version string"
217 default y 162 default y
218 depends on !COMPILE_TEST 163 depends on !COMPILE_TEST
219 help 164 help
220 This will try to automatically deter 165 This will try to automatically determine if the current tree is a
221 release tree by looking for git tags 166 release tree by looking for git tags that belong to the current
222 top of tree revision. 167 top of tree revision.
223 168
224 A string of the format -gxxxxxxxx wi 169 A string of the format -gxxxxxxxx will be added to the localversion
225 if a git-based tree is found. The s 170 if a git-based tree is found. The string generated by this will be
226 appended after any matching localver 171 appended after any matching localversion* files, and after the value
227 set in CONFIG_LOCALVERSION. 172 set in CONFIG_LOCALVERSION.
228 173
229 (The actual string used here is the !! 174 (The actual string used here is the first eight characters produced
230 by running the command: 175 by running the command:
231 176
232 $ git rev-parse --verify HEAD 177 $ git rev-parse --verify HEAD
233 178
234 which is done within the script "scr 179 which is done within the script "scripts/setlocalversion".)
235 180
236 config BUILD_SALT 181 config BUILD_SALT
237 string "Build ID Salt" 182 string "Build ID Salt"
238 default "" 183 default ""
239 help 184 help
240 The build ID is used to link binarie 185 The build ID is used to link binaries and their debug info. Setting
241 this option will use the value in th 186 this option will use the value in the calculation of the build id.
242 This is mostly useful for distributi 187 This is mostly useful for distributions which want to ensure the
243 build is unique between builds. It's 188 build is unique between builds. It's safe to leave the default.
244 189
245 config HAVE_KERNEL_GZIP 190 config HAVE_KERNEL_GZIP
246 bool 191 bool
247 192
248 config HAVE_KERNEL_BZIP2 193 config HAVE_KERNEL_BZIP2
249 bool 194 bool
250 195
251 config HAVE_KERNEL_LZMA 196 config HAVE_KERNEL_LZMA
252 bool 197 bool
253 198
254 config HAVE_KERNEL_XZ 199 config HAVE_KERNEL_XZ
255 bool 200 bool
256 201
257 config HAVE_KERNEL_LZO 202 config HAVE_KERNEL_LZO
258 bool 203 bool
259 204
260 config HAVE_KERNEL_LZ4 205 config HAVE_KERNEL_LZ4
261 bool 206 bool
262 207
263 config HAVE_KERNEL_ZSTD 208 config HAVE_KERNEL_ZSTD
264 bool 209 bool
265 210
266 config HAVE_KERNEL_UNCOMPRESSED 211 config HAVE_KERNEL_UNCOMPRESSED
267 bool 212 bool
268 213
269 choice 214 choice
270 prompt "Kernel compression mode" 215 prompt "Kernel compression mode"
271 default KERNEL_GZIP 216 default KERNEL_GZIP
272 depends on HAVE_KERNEL_GZIP || HAVE_KE 217 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 218 help
274 The linux kernel is a kind of self-e 219 The linux kernel is a kind of self-extracting executable.
275 Several compression algorithms are a 220 Several compression algorithms are available, which differ
276 in efficiency, compression and decom 221 in efficiency, compression and decompression speed.
277 Compression speed is only relevant w 222 Compression speed is only relevant when building a kernel.
278 Decompression speed is relevant at e 223 Decompression speed is relevant at each boot.
279 224
280 If you have any problems with bzip2 225 If you have any problems with bzip2 or lzma compressed
281 kernels, mail me (Alain Knaff) <alain 226 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
282 version of this functionality (bzip2 227 version of this functionality (bzip2 only), for 2.4, was
283 supplied by Christian Ludwig) 228 supplied by Christian Ludwig)
284 229
285 High compression options are mostly 230 High compression options are mostly useful for users, who
286 are low on disk space (embedded syst 231 are low on disk space (embedded systems), but for whom ram
287 size matters less. 232 size matters less.
288 233
289 If in doubt, select 'gzip' 234 If in doubt, select 'gzip'
290 235
291 config KERNEL_GZIP 236 config KERNEL_GZIP
292 bool "Gzip" 237 bool "Gzip"
293 depends on HAVE_KERNEL_GZIP 238 depends on HAVE_KERNEL_GZIP
294 help 239 help
295 The old and tried gzip compression. 240 The old and tried gzip compression. It provides a good balance
296 between compression ratio and decomp 241 between compression ratio and decompression speed.
297 242
298 config KERNEL_BZIP2 243 config KERNEL_BZIP2
299 bool "Bzip2" 244 bool "Bzip2"
300 depends on HAVE_KERNEL_BZIP2 245 depends on HAVE_KERNEL_BZIP2
301 help 246 help
302 Its compression ratio and speed is i 247 Its compression ratio and speed is intermediate.
303 Decompression speed is slowest among 248 Decompression speed is slowest among the choices. The kernel
304 size is about 10% smaller with bzip2 249 size is about 10% smaller with bzip2, in comparison to gzip.
305 Bzip2 uses a large amount of memory. 250 Bzip2 uses a large amount of memory. For modern kernels you
306 will need at least 8MB RAM or more f 251 will need at least 8MB RAM or more for booting.
307 252
308 config KERNEL_LZMA 253 config KERNEL_LZMA
309 bool "LZMA" 254 bool "LZMA"
310 depends on HAVE_KERNEL_LZMA 255 depends on HAVE_KERNEL_LZMA
311 help 256 help
312 This compression algorithm's ratio i 257 This compression algorithm's ratio is best. Decompression speed
313 is between gzip and bzip2. Compress 258 is between gzip and bzip2. Compression is slowest.
314 The kernel size is about 33% smaller 259 The kernel size is about 33% smaller with LZMA in comparison to gzip.
315 260
316 config KERNEL_XZ 261 config KERNEL_XZ
317 bool "XZ" 262 bool "XZ"
318 depends on HAVE_KERNEL_XZ 263 depends on HAVE_KERNEL_XZ
319 help 264 help
320 XZ uses the LZMA2 algorithm and inst 265 XZ uses the LZMA2 algorithm and instruction set specific
321 BCJ filters which can improve compre 266 BCJ filters which can improve compression ratio of executable
322 code. The size of the kernel is abou 267 code. The size of the kernel is about 30% smaller with XZ in
323 comparison to gzip. On architectures 268 comparison to gzip. On architectures for which there is a BCJ
324 filter (i386, x86_64, ARM, ARM64, RI !! 269 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
325 and SPARC), XZ will create a few per !! 270 will create a few percent smaller kernel than plain LZMA.
326 plain LZMA. <<
327 271
328 The speed is about the same as with 272 The speed is about the same as with LZMA: The decompression
329 speed of XZ is better than that of b 273 speed of XZ is better than that of bzip2 but worse than gzip
330 and LZO. Compression is slow. 274 and LZO. Compression is slow.
331 275
332 config KERNEL_LZO 276 config KERNEL_LZO
333 bool "LZO" 277 bool "LZO"
334 depends on HAVE_KERNEL_LZO 278 depends on HAVE_KERNEL_LZO
335 help 279 help
336 Its compression ratio is the poorest 280 Its compression ratio is the poorest among the choices. The kernel
337 size is about 10% bigger than gzip; 281 size is about 10% bigger than gzip; however its speed
338 (both compression and decompression) 282 (both compression and decompression) is the fastest.
339 283
340 config KERNEL_LZ4 284 config KERNEL_LZ4
341 bool "LZ4" 285 bool "LZ4"
342 depends on HAVE_KERNEL_LZ4 286 depends on HAVE_KERNEL_LZ4
343 help 287 help
344 LZ4 is an LZ77-type compressor with 288 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
345 A preliminary version of LZ4 de/comp 289 A preliminary version of LZ4 de/compression tool is available at
346 <https://code.google.com/p/lz4/>. 290 <https://code.google.com/p/lz4/>.
347 291
348 Its compression ratio is worse than 292 Its compression ratio is worse than LZO. The size of the kernel
349 is about 8% bigger than LZO. But the 293 is about 8% bigger than LZO. But the decompression speed is
350 faster than LZO. 294 faster than LZO.
351 295
352 config KERNEL_ZSTD 296 config KERNEL_ZSTD
353 bool "ZSTD" 297 bool "ZSTD"
354 depends on HAVE_KERNEL_ZSTD 298 depends on HAVE_KERNEL_ZSTD
355 help 299 help
356 ZSTD is a compression algorithm targ 300 ZSTD is a compression algorithm targeting intermediate compression
357 with fast decompression speed. It wi 301 with fast decompression speed. It will compress better than GZIP and
358 decompress around the same speed as 302 decompress around the same speed as LZO, but slower than LZ4. You
359 will need at least 192 KB RAM or mor 303 will need at least 192 KB RAM or more for booting. The zstd command
360 line tool is required for compressio 304 line tool is required for compression.
361 305
362 config KERNEL_UNCOMPRESSED 306 config KERNEL_UNCOMPRESSED
363 bool "None" 307 bool "None"
364 depends on HAVE_KERNEL_UNCOMPRESSED 308 depends on HAVE_KERNEL_UNCOMPRESSED
365 help 309 help
366 Produce uncompressed kernel image. T 310 Produce uncompressed kernel image. This option is usually not what
367 you want. It is useful for debugging 311 you want. It is useful for debugging the kernel in slow simulation
368 environments, where decompressing an 312 environments, where decompressing and moving the kernel is awfully
369 slow. This option allows early boot 313 slow. This option allows early boot code to skip the decompressor
370 and jump right at uncompressed kerne 314 and jump right at uncompressed kernel image.
371 315
372 endchoice 316 endchoice
373 317
374 config DEFAULT_INIT 318 config DEFAULT_INIT
375 string "Default init path" 319 string "Default init path"
376 default "" 320 default ""
377 help 321 help
378 This option determines the default i 322 This option determines the default init for the system if no init=
379 option is passed on the kernel comma 323 option is passed on the kernel command line. If the requested path is
380 not present, we will still then move 324 not present, we will still then move on to attempting further
381 locations (e.g. /sbin/init, etc). If 325 locations (e.g. /sbin/init, etc). If this is empty, we will just use
382 the fallback list when init= is not 326 the fallback list when init= is not passed.
383 327
384 config DEFAULT_HOSTNAME 328 config DEFAULT_HOSTNAME
385 string "Default hostname" 329 string "Default hostname"
386 default "(none)" 330 default "(none)"
387 help 331 help
388 This option determines the default s 332 This option determines the default system hostname before userspace
389 calls sethostname(2). The kernel tra 333 calls sethostname(2). The kernel traditionally uses "(none)" here,
390 but you may wish to use a different 334 but you may wish to use a different default here to make a minimal
391 system more usable with less configu 335 system more usable with less configuration.
392 336
>> 337 #
>> 338 # For some reason microblaze and nios2 hard code SWAP=n. Hopefully we can
>> 339 # add proper SWAP support to them, in which case this can be remove.
>> 340 #
>> 341 config ARCH_NO_SWAP
>> 342 bool
>> 343
>> 344 config SWAP
>> 345 bool "Support for paging of anonymous memory (swap)"
>> 346 depends on MMU && BLOCK && !ARCH_NO_SWAP
>> 347 default y
>> 348 help
>> 349 This option allows you to choose whether you want to have support
>> 350 for so called swap devices or swap files in your kernel that are
>> 351 used to provide more virtual memory than the actual RAM present
>> 352 in your computer. If unsure say Y.
>> 353
393 config SYSVIPC 354 config SYSVIPC
394 bool "System V IPC" 355 bool "System V IPC"
395 help 356 help
396 Inter Process Communication is a sui 357 Inter Process Communication is a suite of library functions and
397 system calls which let processes (ru 358 system calls which let processes (running programs) synchronize and
398 exchange information. It is generall 359 exchange information. It is generally considered to be a good thing,
399 and some programs won't run unless y 360 and some programs won't run unless you say Y here. In particular, if
400 you want to run the DOS emulator dos 361 you want to run the DOS emulator dosemu under Linux (read the
401 DOSEMU-HOWTO, available from <http:/ 362 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
402 you'll need to say Y here. 363 you'll need to say Y here.
403 364
404 You can find documentation about IPC 365 You can find documentation about IPC with "info ipc" and also in
405 section 6.4 of the Linux Programmer' 366 section 6.4 of the Linux Programmer's Guide, available from
406 <http://www.tldp.org/guides.html>. 367 <http://www.tldp.org/guides.html>.
407 368
408 config SYSVIPC_SYSCTL 369 config SYSVIPC_SYSCTL
409 bool 370 bool
410 depends on SYSVIPC 371 depends on SYSVIPC
411 depends on SYSCTL 372 depends on SYSCTL
412 default y 373 default y
413 374
414 config SYSVIPC_COMPAT <<
415 def_bool y <<
416 depends on COMPAT && SYSVIPC <<
417 <<
418 config POSIX_MQUEUE 375 config POSIX_MQUEUE
419 bool "POSIX Message Queues" 376 bool "POSIX Message Queues"
420 depends on NET 377 depends on NET
421 help 378 help
422 POSIX variant of message queues is a 379 POSIX variant of message queues is a part of IPC. In POSIX message
423 queues every message has a priority 380 queues every message has a priority which decides about succession
424 of receiving it by a process. If you 381 of receiving it by a process. If you want to compile and run
425 programs written e.g. for Solaris wi 382 programs written e.g. for Solaris with use of its POSIX message
426 queues (functions mq_*) say Y here. 383 queues (functions mq_*) say Y here.
427 384
428 POSIX message queues are visible as 385 POSIX message queues are visible as a filesystem called 'mqueue'
429 and can be mounted somewhere if you 386 and can be mounted somewhere if you want to do filesystem
430 operations on message queues. 387 operations on message queues.
431 388
432 If unsure, say Y. 389 If unsure, say Y.
433 390
434 config POSIX_MQUEUE_SYSCTL 391 config POSIX_MQUEUE_SYSCTL
435 bool 392 bool
436 depends on POSIX_MQUEUE 393 depends on POSIX_MQUEUE
437 depends on SYSCTL 394 depends on SYSCTL
438 default y 395 default y
439 396
440 config WATCH_QUEUE 397 config WATCH_QUEUE
441 bool "General notification queue" 398 bool "General notification queue"
442 default n 399 default n
443 help 400 help
444 401
445 This is a general notification queue 402 This is a general notification queue for the kernel to pass events to
446 userspace by splicing them into pipe 403 userspace by splicing them into pipes. It can be used in conjunction
447 with watches for key/keyring change 404 with watches for key/keyring change notifications and device
448 notifications. 405 notifications.
449 406
450 See Documentation/core-api/watch_que !! 407 See Documentation/watch_queue.rst
451 408
452 config CROSS_MEMORY_ATTACH 409 config CROSS_MEMORY_ATTACH
453 bool "Enable process_vm_readv/writev s 410 bool "Enable process_vm_readv/writev syscalls"
454 depends on MMU 411 depends on MMU
455 default y 412 default y
456 help 413 help
457 Enabling this option adds the system 414 Enabling this option adds the system calls process_vm_readv and
458 process_vm_writev which allow a proc 415 process_vm_writev which allow a process with the correct privileges
459 to directly read from or write to an 416 to directly read from or write to another process' address space.
460 See the man page for more details. 417 See the man page for more details.
461 418
462 config USELIB 419 config USELIB
463 bool "uselib syscall (for libc5 and ea !! 420 bool "uselib syscall"
464 default ALPHA || M68K || SPARC !! 421 def_bool ALPHA || M68K || SPARC || X86_32 || IA32_EMULATION
465 help 422 help
466 This option enables the uselib sysca 423 This option enables the uselib syscall, a system call used in the
467 dynamic linker from libc5 and earlie 424 dynamic linker from libc5 and earlier. glibc does not use this
468 system call. If you intend to run p 425 system call. If you intend to run programs built on libc5 or
469 earlier, you may need to enable this 426 earlier, you may need to enable this syscall. Current systems
470 running glibc can safely disable thi 427 running glibc can safely disable this.
471 428
472 config AUDIT 429 config AUDIT
473 bool "Auditing support" 430 bool "Auditing support"
474 depends on NET 431 depends on NET
475 help 432 help
476 Enable auditing infrastructure that 433 Enable auditing infrastructure that can be used with another
477 kernel subsystem, such as SELinux (w 434 kernel subsystem, such as SELinux (which requires this for
478 logging of avc messages output). Sy 435 logging of avc messages output). System call auditing is included
479 on architectures which support it. 436 on architectures which support it.
480 437
481 config HAVE_ARCH_AUDITSYSCALL 438 config HAVE_ARCH_AUDITSYSCALL
482 bool 439 bool
483 440
484 config AUDITSYSCALL 441 config AUDITSYSCALL
485 def_bool y 442 def_bool y
486 depends on AUDIT && HAVE_ARCH_AUDITSYS 443 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
487 select FSNOTIFY 444 select FSNOTIFY
488 445
489 source "kernel/irq/Kconfig" 446 source "kernel/irq/Kconfig"
490 source "kernel/time/Kconfig" 447 source "kernel/time/Kconfig"
491 source "kernel/bpf/Kconfig" 448 source "kernel/bpf/Kconfig"
492 source "kernel/Kconfig.preempt" 449 source "kernel/Kconfig.preempt"
493 450
494 menu "CPU/Task time and stats accounting" 451 menu "CPU/Task time and stats accounting"
495 452
496 config VIRT_CPU_ACCOUNTING 453 config VIRT_CPU_ACCOUNTING
497 bool 454 bool
498 455
499 choice 456 choice
500 prompt "Cputime accounting" 457 prompt "Cputime accounting"
501 default TICK_CPU_ACCOUNTING !! 458 default TICK_CPU_ACCOUNTING if !PPC64
>> 459 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
502 460
503 # Kind of a stub config for the pure tick base 461 # Kind of a stub config for the pure tick based cputime accounting
504 config TICK_CPU_ACCOUNTING 462 config TICK_CPU_ACCOUNTING
505 bool "Simple tick based cputime accoun 463 bool "Simple tick based cputime accounting"
506 depends on !S390 && !NO_HZ_FULL 464 depends on !S390 && !NO_HZ_FULL
507 help 465 help
508 This is the basic tick based cputime 466 This is the basic tick based cputime accounting that maintains
509 statistics about user, system and id 467 statistics about user, system and idle time spent on per jiffies
510 granularity. 468 granularity.
511 469
512 If unsure, say Y. 470 If unsure, say Y.
513 471
514 config VIRT_CPU_ACCOUNTING_NATIVE 472 config VIRT_CPU_ACCOUNTING_NATIVE
515 bool "Deterministic task and CPU time 473 bool "Deterministic task and CPU time accounting"
516 depends on HAVE_VIRT_CPU_ACCOUNTING && 474 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
517 select VIRT_CPU_ACCOUNTING 475 select VIRT_CPU_ACCOUNTING
518 help 476 help
519 Select this option to enable more ac 477 Select this option to enable more accurate task and CPU time
520 accounting. This is done by reading 478 accounting. This is done by reading a CPU counter on each
521 kernel entry and exit and on transit 479 kernel entry and exit and on transitions within the kernel
522 between system, softirq and hardirq 480 between system, softirq and hardirq state, so there is a
523 small performance impact. In the ca 481 small performance impact. In the case of s390 or IBM POWER > 5,
524 this also enables accounting of stol 482 this also enables accounting of stolen time on logically-partitioned
525 systems. 483 systems.
526 484
527 config VIRT_CPU_ACCOUNTING_GEN 485 config VIRT_CPU_ACCOUNTING_GEN
528 bool "Full dynticks CPU time accountin 486 bool "Full dynticks CPU time accounting"
529 depends on HAVE_CONTEXT_TRACKING_USER !! 487 depends on HAVE_CONTEXT_TRACKING
530 depends on HAVE_VIRT_CPU_ACCOUNTING_GE 488 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
531 depends on GENERIC_CLOCKEVENTS 489 depends on GENERIC_CLOCKEVENTS
532 select VIRT_CPU_ACCOUNTING 490 select VIRT_CPU_ACCOUNTING
533 select CONTEXT_TRACKING_USER !! 491 select CONTEXT_TRACKING
534 help 492 help
535 Select this option to enable task an 493 Select this option to enable task and CPU time accounting on full
536 dynticks systems. This accounting is 494 dynticks systems. This accounting is implemented by watching every
537 kernel-user boundaries using the con 495 kernel-user boundaries using the context tracking subsystem.
538 The accounting is thus performed at 496 The accounting is thus performed at the expense of some significant
539 overhead. 497 overhead.
540 498
541 For now this is only useful if you a 499 For now this is only useful if you are working on the full
542 dynticks subsystem development. 500 dynticks subsystem development.
543 501
544 If unsure, say N. 502 If unsure, say N.
545 503
546 endchoice 504 endchoice
547 505
548 config IRQ_TIME_ACCOUNTING 506 config IRQ_TIME_ACCOUNTING
549 bool "Fine granularity task level IRQ 507 bool "Fine granularity task level IRQ time accounting"
550 depends on HAVE_IRQ_TIME_ACCOUNTING && 508 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
551 help 509 help
552 Select this option to enable fine gr 510 Select this option to enable fine granularity task irq time
553 accounting. This is done by reading 511 accounting. This is done by reading a timestamp on each
554 transitions between softirq and hard 512 transitions between softirq and hardirq state, so there can be a
555 small performance impact. 513 small performance impact.
556 514
557 If in doubt, say N here. 515 If in doubt, say N here.
558 516
559 config HAVE_SCHED_AVG_IRQ 517 config HAVE_SCHED_AVG_IRQ
560 def_bool y 518 def_bool y
561 depends on IRQ_TIME_ACCOUNTING || PARA 519 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING
562 depends on SMP 520 depends on SMP
563 521
564 config SCHED_HW_PRESSURE !! 522 config SCHED_THERMAL_PRESSURE
565 bool 523 bool
566 default y if ARM && ARM_CPU_TOPOLOGY 524 default y if ARM && ARM_CPU_TOPOLOGY
567 default y if ARM64 525 default y if ARM64
568 depends on SMP 526 depends on SMP
569 depends on CPU_FREQ_THERMAL 527 depends on CPU_FREQ_THERMAL
570 help 528 help
571 Select this option to enable HW pres !! 529 Select this option to enable thermal pressure accounting in the
572 scheduler. HW pressure is the value !! 530 scheduler. Thermal pressure is the value conveyed to the scheduler
573 that reflects the reduction in CPU c 531 that reflects the reduction in CPU compute capacity resulted from
574 HW throttling. HW throttling occurs !! 532 thermal throttling. Thermal throttling occurs when the performance of
575 a CPU is capped due to high operatin !! 533 a CPU is capped due to high operating temperatures.
576 534
577 If selected, the scheduler will be a 535 If selected, the scheduler will be able to balance tasks accordingly,
578 i.e. put less load on throttled CPUs 536 i.e. put less load on throttled CPUs than on non/less throttled ones.
579 537
580 This requires the architecture to im 538 This requires the architecture to implement
581 arch_update_hw_pressure() and arch_s !! 539 arch_set_thermal_pressure() and arch_scale_thermal_pressure().
582 540
583 config BSD_PROCESS_ACCT 541 config BSD_PROCESS_ACCT
584 bool "BSD Process Accounting" 542 bool "BSD Process Accounting"
585 depends on MULTIUSER 543 depends on MULTIUSER
586 help 544 help
587 If you say Y here, a user level prog 545 If you say Y here, a user level program will be able to instruct the
588 kernel (via a special system call) t 546 kernel (via a special system call) to write process accounting
589 information to a file: whenever a pr 547 information to a file: whenever a process exits, information about
590 that process will be appended to the 548 that process will be appended to the file by the kernel. The
591 information includes things such as 549 information includes things such as creation time, owning user,
592 command name, memory usage, controll 550 command name, memory usage, controlling terminal etc. (the complete
593 list is in the struct acct in <file: 551 list is in the struct acct in <file:include/linux/acct.h>). It is
594 up to the user level program to do u 552 up to the user level program to do useful things with this
595 information. This is generally a go 553 information. This is generally a good idea, so say Y.
596 554
597 config BSD_PROCESS_ACCT_V3 555 config BSD_PROCESS_ACCT_V3
598 bool "BSD Process Accounting version 3 556 bool "BSD Process Accounting version 3 file format"
599 depends on BSD_PROCESS_ACCT 557 depends on BSD_PROCESS_ACCT
600 default n 558 default n
601 help 559 help
602 If you say Y here, the process accou 560 If you say Y here, the process accounting information is written
603 in a new file format that also logs 561 in a new file format that also logs the process IDs of each
604 process and its parent. Note that th 562 process and its parent. Note that this file format is incompatible
605 with previous v0/v1/v2 file formats, 563 with previous v0/v1/v2 file formats, so you will need updated tools
606 for processing it. A preliminary ver 564 for processing it. A preliminary version of these tools is available
607 at <http://www.gnu.org/software/acct 565 at <http://www.gnu.org/software/acct/>.
608 566
609 config TASKSTATS 567 config TASKSTATS
610 bool "Export task/process statistics t 568 bool "Export task/process statistics through netlink"
611 depends on NET 569 depends on NET
612 depends on MULTIUSER 570 depends on MULTIUSER
613 default n 571 default n
614 help 572 help
615 Export selected statistics for tasks 573 Export selected statistics for tasks/processes through the
616 generic netlink interface. Unlike BS 574 generic netlink interface. Unlike BSD process accounting, the
617 statistics are available during the 575 statistics are available during the lifetime of tasks/processes as
618 responses to commands. Like BSD acco 576 responses to commands. Like BSD accounting, they are sent to user
619 space on task exit. 577 space on task exit.
620 578
621 Say N if unsure. 579 Say N if unsure.
622 580
623 config TASK_DELAY_ACCT 581 config TASK_DELAY_ACCT
624 bool "Enable per-task delay accounting 582 bool "Enable per-task delay accounting"
625 depends on TASKSTATS 583 depends on TASKSTATS
626 select SCHED_INFO 584 select SCHED_INFO
627 help 585 help
628 Collect information on time spent by 586 Collect information on time spent by a task waiting for system
629 resources like cpu, synchronous bloc 587 resources like cpu, synchronous block I/O completion and swapping
630 in pages. Such statistics can help i 588 in pages. Such statistics can help in setting a task's priorities
631 relative to other tasks for cpu, io, 589 relative to other tasks for cpu, io, rss limits etc.
632 590
633 Say N if unsure. 591 Say N if unsure.
634 592
635 config TASK_XACCT 593 config TASK_XACCT
636 bool "Enable extended accounting over 594 bool "Enable extended accounting over taskstats"
637 depends on TASKSTATS 595 depends on TASKSTATS
638 help 596 help
639 Collect extended task accounting dat 597 Collect extended task accounting data and send the data
640 to userland for processing over the 598 to userland for processing over the taskstats interface.
641 599
642 Say N if unsure. 600 Say N if unsure.
643 601
644 config TASK_IO_ACCOUNTING 602 config TASK_IO_ACCOUNTING
645 bool "Enable per-task storage I/O acco 603 bool "Enable per-task storage I/O accounting"
646 depends on TASK_XACCT 604 depends on TASK_XACCT
647 help 605 help
648 Collect information on the number of 606 Collect information on the number of bytes of storage I/O which this
649 task has caused. 607 task has caused.
650 608
651 Say N if unsure. 609 Say N if unsure.
652 610
653 config PSI 611 config PSI
654 bool "Pressure stall information track 612 bool "Pressure stall information tracking"
655 select KERNFS <<
656 help 613 help
657 Collect metrics that indicate how ov 614 Collect metrics that indicate how overcommitted the CPU, memory,
658 and IO capacity are in the system. 615 and IO capacity are in the system.
659 616
660 If you say Y here, the kernel will c 617 If you say Y here, the kernel will create /proc/pressure/ with the
661 pressure statistics files cpu, memor 618 pressure statistics files cpu, memory, and io. These will indicate
662 the share of walltime in which some 619 the share of walltime in which some or all tasks in the system are
663 delayed due to contention of the res 620 delayed due to contention of the respective resource.
664 621
665 In kernels with cgroup support, cgro 622 In kernels with cgroup support, cgroups (cgroup2 only) will
666 have cpu.pressure, memory.pressure, 623 have cpu.pressure, memory.pressure, and io.pressure files,
667 which aggregate pressure stalls for 624 which aggregate pressure stalls for the grouped tasks only.
668 625
669 For more details see Documentation/a 626 For more details see Documentation/accounting/psi.rst.
670 627
671 Say N if unsure. 628 Say N if unsure.
672 629
673 config PSI_DEFAULT_DISABLED 630 config PSI_DEFAULT_DISABLED
674 bool "Require boot parameter to enable 631 bool "Require boot parameter to enable pressure stall information tracking"
675 default n 632 default n
676 depends on PSI 633 depends on PSI
677 help 634 help
678 If set, pressure stall information t 635 If set, pressure stall information tracking will be disabled
679 per default but can be enabled throu 636 per default but can be enabled through passing psi=1 on the
680 kernel commandline during boot. 637 kernel commandline during boot.
681 638
682 This feature adds some code to the t 639 This feature adds some code to the task wakeup and sleep
683 paths of the scheduler. The overhead 640 paths of the scheduler. The overhead is too low to affect
684 common scheduling-intense workloads 641 common scheduling-intense workloads in practice (such as
685 webservers, memcache), but it does s 642 webservers, memcache), but it does show up in artificial
686 scheduler stress tests, such as hack 643 scheduler stress tests, such as hackbench.
687 644
688 If you are paranoid and not sure wha 645 If you are paranoid and not sure what the kernel will be
689 used for, say Y. 646 used for, say Y.
690 647
691 Say N if unsure. 648 Say N if unsure.
692 649
693 endmenu # "CPU/Task time and stats accounting" 650 endmenu # "CPU/Task time and stats accounting"
694 651
695 config CPU_ISOLATION 652 config CPU_ISOLATION
696 bool "CPU isolation" 653 bool "CPU isolation"
697 depends on SMP || COMPILE_TEST 654 depends on SMP || COMPILE_TEST
698 default y 655 default y
699 help 656 help
700 Make sure that CPUs running critical 657 Make sure that CPUs running critical tasks are not disturbed by
701 any source of "noise" such as unboun 658 any source of "noise" such as unbound workqueues, timers, kthreads...
702 Unbound jobs get offloaded to housek 659 Unbound jobs get offloaded to housekeeping CPUs. This is driven by
703 the "isolcpus=" boot parameter. 660 the "isolcpus=" boot parameter.
704 661
705 Say Y if unsure. 662 Say Y if unsure.
706 663
707 source "kernel/rcu/Kconfig" 664 source "kernel/rcu/Kconfig"
708 665
>> 666 config BUILD_BIN2C
>> 667 bool
>> 668 default n
>> 669
709 config IKCONFIG 670 config IKCONFIG
710 tristate "Kernel .config support" 671 tristate "Kernel .config support"
711 help 672 help
712 This option enables the complete Lin 673 This option enables the complete Linux kernel ".config" file
713 contents to be saved in the kernel. 674 contents to be saved in the kernel. It provides documentation
714 of which kernel options are used in 675 of which kernel options are used in a running kernel or in an
715 on-disk kernel. This information ca 676 on-disk kernel. This information can be extracted from the kernel
716 image file with the script scripts/e 677 image file with the script scripts/extract-ikconfig and used as
717 input to rebuild the current kernel 678 input to rebuild the current kernel or to build another kernel.
718 It can also be extracted from a runn 679 It can also be extracted from a running kernel by reading
719 /proc/config.gz if enabled (below). 680 /proc/config.gz if enabled (below).
720 681
721 config IKCONFIG_PROC 682 config IKCONFIG_PROC
722 bool "Enable access to .config through 683 bool "Enable access to .config through /proc/config.gz"
723 depends on IKCONFIG && PROC_FS 684 depends on IKCONFIG && PROC_FS
724 help 685 help
725 This option enables access to the ke 686 This option enables access to the kernel configuration file
726 through /proc/config.gz. 687 through /proc/config.gz.
727 688
728 config IKHEADERS 689 config IKHEADERS
729 tristate "Enable kernel headers throug 690 tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz"
730 depends on SYSFS 691 depends on SYSFS
731 help 692 help
732 This option enables access to the in 693 This option enables access to the in-kernel headers that are generated during
733 the build process. These can be used 694 the build process. These can be used to build eBPF tracing programs,
734 or similar programs. If you build t 695 or similar programs. If you build the headers as a module, a module called
735 kheaders.ko is built which can be lo 696 kheaders.ko is built which can be loaded on-demand to get access to headers.
736 697
737 config LOG_BUF_SHIFT 698 config LOG_BUF_SHIFT
738 int "Kernel log buffer size (16 => 64K 699 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
739 range 12 25 !! 700 range 12 25 if !H8300
>> 701 range 12 19 if H8300
740 default 17 702 default 17
741 depends on PRINTK 703 depends on PRINTK
742 help 704 help
743 Select the minimal kernel log buffer 705 Select the minimal kernel log buffer size as a power of 2.
744 The final size is affected by LOG_CP 706 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
745 parameter, see below. Any higher siz 707 parameter, see below. Any higher size also might be forced
746 by "log_buf_len" boot parameter. 708 by "log_buf_len" boot parameter.
747 709
748 Examples: 710 Examples:
749 17 => 128 KB 711 17 => 128 KB
750 16 => 64 KB 712 16 => 64 KB
751 15 => 32 KB 713 15 => 32 KB
752 14 => 16 KB 714 14 => 16 KB
753 13 => 8 KB 715 13 => 8 KB
754 12 => 4 KB 716 12 => 4 KB
755 717
756 config LOG_CPU_MAX_BUF_SHIFT 718 config LOG_CPU_MAX_BUF_SHIFT
757 int "CPU kernel log buffer size contri 719 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
758 depends on SMP 720 depends on SMP
759 range 0 21 721 range 0 21
>> 722 default 12 if !BASE_SMALL
760 default 0 if BASE_SMALL 723 default 0 if BASE_SMALL
761 default 12 <<
762 depends on PRINTK 724 depends on PRINTK
763 help 725 help
764 This option allows to increase the d 726 This option allows to increase the default ring buffer size
765 according to the number of CPUs. The 727 according to the number of CPUs. The value defines the contribution
766 of each CPU as a power of 2. The use 728 of each CPU as a power of 2. The used space is typically only few
767 lines however it might be much more 729 lines however it might be much more when problems are reported,
768 e.g. backtraces. 730 e.g. backtraces.
769 731
770 The increased size means that a new 732 The increased size means that a new buffer has to be allocated and
771 the original static one is unused. I 733 the original static one is unused. It makes sense only on systems
772 with more CPUs. Therefore this value 734 with more CPUs. Therefore this value is used only when the sum of
773 contributions is greater than the ha 735 contributions is greater than the half of the default kernel ring
774 buffer as defined by LOG_BUF_SHIFT. 736 buffer as defined by LOG_BUF_SHIFT. The default values are set
775 so that more than 16 CPUs are needed 737 so that more than 16 CPUs are needed to trigger the allocation.
776 738
777 Also this option is ignored when "lo 739 Also this option is ignored when "log_buf_len" kernel parameter is
778 used as it forces an exact (power of 740 used as it forces an exact (power of two) size of the ring buffer.
779 741
780 The number of possible CPUs is used 742 The number of possible CPUs is used for this computation ignoring
781 hotplugging making the computation o 743 hotplugging making the computation optimal for the worst case
782 scenario while allowing a simple alg 744 scenario while allowing a simple algorithm to be used from bootup.
783 745
784 Examples shift values and their mean 746 Examples shift values and their meaning:
785 17 => 128 KB for each CPU 747 17 => 128 KB for each CPU
786 16 => 64 KB for each CPU 748 16 => 64 KB for each CPU
787 15 => 32 KB for each CPU 749 15 => 32 KB for each CPU
788 14 => 16 KB for each CPU 750 14 => 16 KB for each CPU
789 13 => 8 KB for each CPU 751 13 => 8 KB for each CPU
790 12 => 4 KB for each CPU 752 12 => 4 KB for each CPU
791 753
792 config PRINTK_INDEX !! 754 config PRINTK_SAFE_LOG_BUF_SHIFT
793 bool "Printk indexing debugfs interfac !! 755 int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)"
794 depends on PRINTK && DEBUG_FS !! 756 range 10 21
795 help !! 757 default 13
796 Add support for indexing of all prin !! 758 depends on PRINTK
797 at <debugfs>/printk/index/<module>. !! 759 help
798 !! 760 Select the size of an alternate printk per-CPU buffer where messages
799 This can be used as part of maintain !! 761 printed from usafe contexts are temporary stored. One example would
800 /dev/kmsg, as it permits auditing th !! 762 be NMI messages, another one - printk recursion. The messages are
801 kernel, allowing detection of cases !! 763 copied to the main log buffer in a safe context to avoid a deadlock.
802 changed or no longer present. !! 764 The value defines the size as a power of 2.
>> 765
>> 766 Those messages are rare and limited. The largest one is when
>> 767 a backtrace is printed. It usually fits into 4KB. Select
>> 768 8KB if you want to be on the safe side.
803 769
804 There is no additional runtime cost !! 770 Examples:
>> 771 17 => 128 KB for each CPU
>> 772 16 => 64 KB for each CPU
>> 773 15 => 32 KB for each CPU
>> 774 14 => 16 KB for each CPU
>> 775 13 => 8 KB for each CPU
>> 776 12 => 4 KB for each CPU
805 777
806 # 778 #
807 # Architectures with an unreliable sched_clock 779 # Architectures with an unreliable sched_clock() should select this:
808 # 780 #
809 config HAVE_UNSTABLE_SCHED_CLOCK 781 config HAVE_UNSTABLE_SCHED_CLOCK
810 bool 782 bool
811 783
812 config GENERIC_SCHED_CLOCK 784 config GENERIC_SCHED_CLOCK
813 bool 785 bool
814 786
815 menu "Scheduler features" 787 menu "Scheduler features"
816 788
817 config UCLAMP_TASK 789 config UCLAMP_TASK
818 bool "Enable utilization clamping for 790 bool "Enable utilization clamping for RT/FAIR tasks"
819 depends on CPU_FREQ_GOV_SCHEDUTIL 791 depends on CPU_FREQ_GOV_SCHEDUTIL
820 help 792 help
821 This feature enables the scheduler t 793 This feature enables the scheduler to track the clamped utilization
822 of each CPU based on RUNNABLE tasks 794 of each CPU based on RUNNABLE tasks scheduled on that CPU.
823 795
824 With this option, the user can speci 796 With this option, the user can specify the min and max CPU
825 utilization allowed for RUNNABLE tas 797 utilization allowed for RUNNABLE tasks. The max utilization defines
826 the maximum frequency a task should 798 the maximum frequency a task should use while the min utilization
827 defines the minimum frequency it sho 799 defines the minimum frequency it should use.
828 800
829 Both min and max utilization clamp v 801 Both min and max utilization clamp values are hints to the scheduler,
830 aiming at improving its frequency se 802 aiming at improving its frequency selection policy, but they do not
831 enforce or grant any specific bandwi 803 enforce or grant any specific bandwidth for tasks.
832 804
833 If in doubt, say N. 805 If in doubt, say N.
834 806
835 config UCLAMP_BUCKETS_COUNT 807 config UCLAMP_BUCKETS_COUNT
836 int "Number of supported utilization c 808 int "Number of supported utilization clamp buckets"
837 range 5 20 809 range 5 20
838 default 5 810 default 5
839 depends on UCLAMP_TASK 811 depends on UCLAMP_TASK
840 help 812 help
841 Defines the number of clamp buckets 813 Defines the number of clamp buckets to use. The range of each bucket
842 will be SCHED_CAPACITY_SCALE/UCLAMP_ 814 will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the
843 number of clamp buckets the finer th 815 number of clamp buckets the finer their granularity and the higher
844 the precision of clamping aggregatio 816 the precision of clamping aggregation and tracking at run-time.
845 817
846 For example, with the minimum config 818 For example, with the minimum configuration value we will have 5
847 clamp buckets tracking 20% utilizati 819 clamp buckets tracking 20% utilization each. A 25% boosted tasks will
848 be refcounted in the [20..39]% bucke 820 be refcounted in the [20..39]% bucket and will set the bucket clamp
849 effective value to 25%. 821 effective value to 25%.
850 If a second 30% boosted task should 822 If a second 30% boosted task should be co-scheduled on the same CPU,
851 that task will be refcounted in the 823 that task will be refcounted in the same bucket of the first task and
852 it will boost the bucket clamp effec 824 it will boost the bucket clamp effective value to 30%.
853 The clamp effective value of a bucke 825 The clamp effective value of a bucket is reset to its nominal value
854 (20% in the example above) when ther 826 (20% in the example above) when there are no more tasks refcounted in
855 that bucket. 827 that bucket.
856 828
857 An additional boost/capping margin c 829 An additional boost/capping margin can be added to some tasks. In the
858 example above the 25% task will be b 830 example above the 25% task will be boosted to 30% until it exits the
859 CPU. If that should be considered no 831 CPU. If that should be considered not acceptable on certain systems,
860 it's always possible to reduce the m 832 it's always possible to reduce the margin by increasing the number of
861 clamp buckets to trade off used memo 833 clamp buckets to trade off used memory for run-time tracking
862 precision. 834 precision.
863 835
864 If in doubt, use the default value. 836 If in doubt, use the default value.
865 837
866 endmenu 838 endmenu
867 839
868 # 840 #
869 # For architectures that want to enable the su 841 # For architectures that want to enable the support for NUMA-affine scheduler
870 # balancing logic: 842 # balancing logic:
871 # 843 #
872 config ARCH_SUPPORTS_NUMA_BALANCING 844 config ARCH_SUPPORTS_NUMA_BALANCING
873 bool 845 bool
874 846
875 # 847 #
876 # For architectures that prefer to flush all T 848 # For architectures that prefer to flush all TLBs after a number of pages
877 # are unmapped instead of sending one IPI per 849 # are unmapped instead of sending one IPI per page to flush. The architecture
878 # must provide guarantees on what happens if a 850 # must provide guarantees on what happens if a clean TLB cache entry is
879 # written after the unmap. Details are in mm/r 851 # written after the unmap. Details are in mm/rmap.c near the check for
880 # should_defer_flush. The architecture should 852 # should_defer_flush. The architecture should also consider if the full flush
881 # and the refill costs are offset by the savin 853 # and the refill costs are offset by the savings of sending fewer IPIs.
882 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 854 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
883 bool 855 bool
884 856
885 config CC_HAS_INT128 857 config CC_HAS_INT128
886 def_bool !$(cc-option,$(m64-flag) -D__ 858 def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT
887 859
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 # 860 #
915 # For architectures that know their GCC __int1 861 # For architectures that know their GCC __int128 support is sound
916 # 862 #
917 config ARCH_SUPPORTS_INT128 863 config ARCH_SUPPORTS_INT128
918 bool 864 bool
919 865
920 # For architectures that (ab)use NUMA to repre 866 # For architectures that (ab)use NUMA to represent different memory regions
921 # all cpu-local but of different latencies, su 867 # all cpu-local but of different latencies, such as SuperH.
922 # 868 #
923 config ARCH_WANT_NUMA_VARIABLE_LOCALITY 869 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
924 bool 870 bool
925 871
926 config NUMA_BALANCING 872 config NUMA_BALANCING
927 bool "Memory placement aware NUMA sche 873 bool "Memory placement aware NUMA scheduler"
928 depends on ARCH_SUPPORTS_NUMA_BALANCIN 874 depends on ARCH_SUPPORTS_NUMA_BALANCING
929 depends on !ARCH_WANT_NUMA_VARIABLE_LO 875 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
930 depends on SMP && NUMA && MIGRATION && !! 876 depends on SMP && NUMA && MIGRATION
931 help 877 help
932 This option adds support for automat 878 This option adds support for automatic NUMA aware memory/task placement.
933 The mechanism is quite primitive and 879 The mechanism is quite primitive and is based on migrating memory when
934 it has references to the node the ta 880 it has references to the node the task is running on.
935 881
936 This system will be inactive on UMA 882 This system will be inactive on UMA systems.
937 883
938 config NUMA_BALANCING_DEFAULT_ENABLED 884 config NUMA_BALANCING_DEFAULT_ENABLED
939 bool "Automatically enable NUMA aware 885 bool "Automatically enable NUMA aware memory/task placement"
940 default y 886 default y
941 depends on NUMA_BALANCING 887 depends on NUMA_BALANCING
942 help 888 help
943 If set, automatic NUMA balancing wil 889 If set, automatic NUMA balancing will be enabled if running on a NUMA
944 machine. 890 machine.
945 891
946 config SLAB_OBJ_EXT <<
947 bool <<
948 <<
949 menuconfig CGROUPS 892 menuconfig CGROUPS
950 bool "Control Group support" 893 bool "Control Group support"
951 select KERNFS 894 select KERNFS
952 help 895 help
953 This option adds support for groupin 896 This option adds support for grouping sets of processes together, for
954 use with process control subsystems 897 use with process control subsystems such as Cpusets, CFS, memory
955 controls or device isolation. 898 controls or device isolation.
956 See 899 See
957 - Documentation/scheduler/sche 900 - Documentation/scheduler/sched-design-CFS.rst (CFS)
958 - Documentation/admin-guide/cg 901 - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation
959 and 902 and resource control)
960 903
961 Say N if unsure. 904 Say N if unsure.
962 905
963 if CGROUPS 906 if CGROUPS
964 907
965 config PAGE_COUNTER 908 config PAGE_COUNTER
966 bool 909 bool
967 910
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 911 config MEMCG
979 bool "Memory controller" 912 bool "Memory controller"
980 select PAGE_COUNTER 913 select PAGE_COUNTER
981 select EVENTFD 914 select EVENTFD
982 select SLAB_OBJ_EXT <<
983 help 915 help
984 Provides control over the memory foo 916 Provides control over the memory footprint of tasks in a cgroup.
985 917
986 config MEMCG_V1 !! 918 config MEMCG_SWAP
987 bool "Legacy cgroup v1 memory controll !! 919 bool
988 depends on MEMCG !! 920 depends on MEMCG && SWAP
989 default n !! 921 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 922
1001 Say N if unsure. !! 923 config MEMCG_KMEM
>> 924 bool
>> 925 depends on MEMCG && !SLOB
>> 926 default y
1002 927
1003 config BLK_CGROUP 928 config BLK_CGROUP
1004 bool "IO controller" 929 bool "IO controller"
1005 depends on BLOCK 930 depends on BLOCK
1006 default n 931 default n
1007 help 932 help
1008 Generic block IO controller cgroup in 933 Generic block IO controller cgroup interface. This is the common
1009 cgroup interface which should be used 934 cgroup interface which should be used by various IO controlling
1010 policies. 935 policies.
1011 936
1012 Currently, CFQ IO scheduler uses it t 937 Currently, CFQ IO scheduler uses it to recognize task groups and
1013 control disk bandwidth allocation (pr 938 control disk bandwidth allocation (proportional time slice allocation)
1014 to such task groups. It is also used 939 to such task groups. It is also used by bio throttling logic in
1015 block layer to implement upper limit 940 block layer to implement upper limit in IO rates on a device.
1016 941
1017 This option only enables generic Bloc 942 This option only enables generic Block IO controller infrastructure.
1018 One needs to also enable actual IO co 943 One needs to also enable actual IO controlling logic/policy. For
1019 enabling proportional weight division 944 enabling proportional weight division of disk bandwidth in CFQ, set
1020 CONFIG_BFQ_GROUP_IOSCHED=y; for enabl 945 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1021 CONFIG_BLK_DEV_THROTTLING=y. 946 CONFIG_BLK_DEV_THROTTLING=y.
1022 947
1023 See Documentation/admin-guide/cgroup- 948 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information.
1024 949
1025 config CGROUP_WRITEBACK 950 config CGROUP_WRITEBACK
1026 bool 951 bool
1027 depends on MEMCG && BLK_CGROUP 952 depends on MEMCG && BLK_CGROUP
1028 default y 953 default y
1029 954
1030 menuconfig CGROUP_SCHED 955 menuconfig CGROUP_SCHED
1031 bool "CPU controller" 956 bool "CPU controller"
1032 default n 957 default n
1033 help 958 help
1034 This feature lets CPU scheduler rec 959 This feature lets CPU scheduler recognize task groups and control CPU
1035 bandwidth allocation to such task g 960 bandwidth allocation to such task groups. It uses cgroups to group
1036 tasks. 961 tasks.
1037 962
1038 if CGROUP_SCHED 963 if CGROUP_SCHED
1039 config GROUP_SCHED_WEIGHT <<
1040 def_bool n <<
1041 <<
1042 config FAIR_GROUP_SCHED 964 config FAIR_GROUP_SCHED
1043 bool "Group scheduling for SCHED_OTHE 965 bool "Group scheduling for SCHED_OTHER"
1044 depends on CGROUP_SCHED 966 depends on CGROUP_SCHED
1045 select GROUP_SCHED_WEIGHT <<
1046 default CGROUP_SCHED 967 default CGROUP_SCHED
1047 968
1048 config CFS_BANDWIDTH 969 config CFS_BANDWIDTH
1049 bool "CPU bandwidth provisioning for 970 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1050 depends on FAIR_GROUP_SCHED 971 depends on FAIR_GROUP_SCHED
1051 default n 972 default n
1052 help 973 help
1053 This option allows users to define 974 This option allows users to define CPU bandwidth rates (limits) for
1054 tasks running within the fair group 975 tasks running within the fair group scheduler. Groups with no limit
1055 set are considered to be unconstrai 976 set are considered to be unconstrained and will run with no
1056 restriction. 977 restriction.
1057 See Documentation/scheduler/sched-b 978 See Documentation/scheduler/sched-bwc.rst for more information.
1058 979
1059 config RT_GROUP_SCHED 980 config RT_GROUP_SCHED
1060 bool "Group scheduling for SCHED_RR/F 981 bool "Group scheduling for SCHED_RR/FIFO"
1061 depends on CGROUP_SCHED 982 depends on CGROUP_SCHED
1062 default n 983 default n
1063 help 984 help
1064 This feature lets you explicitly al 985 This feature lets you explicitly allocate real CPU bandwidth
1065 to task groups. If enabled, it will 986 to task groups. If enabled, it will also make it impossible to
1066 schedule realtime tasks for non-roo 987 schedule realtime tasks for non-root users until you allocate
1067 realtime bandwidth for them. 988 realtime bandwidth for them.
1068 See Documentation/scheduler/sched-r 989 See Documentation/scheduler/sched-rt-group.rst for more information.
1069 990
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 991 endif #CGROUP_SCHED
1077 992
1078 config SCHED_MM_CID <<
1079 def_bool y <<
1080 depends on SMP && RSEQ <<
1081 <<
1082 config UCLAMP_TASK_GROUP 993 config UCLAMP_TASK_GROUP
1083 bool "Utilization clamping per group 994 bool "Utilization clamping per group of tasks"
1084 depends on CGROUP_SCHED 995 depends on CGROUP_SCHED
1085 depends on UCLAMP_TASK 996 depends on UCLAMP_TASK
1086 default n 997 default n
1087 help 998 help
1088 This feature enables the scheduler 999 This feature enables the scheduler to track the clamped utilization
1089 of each CPU based on RUNNABLE tasks 1000 of each CPU based on RUNNABLE tasks currently scheduled on that CPU.
1090 1001
1091 When this option is enabled, the us 1002 When this option is enabled, the user can specify a min and max
1092 CPU bandwidth which is allowed for 1003 CPU bandwidth which is allowed for each single task in a group.
1093 The max bandwidth allows to clamp t 1004 The max bandwidth allows to clamp the maximum frequency a task
1094 can use, while the min bandwidth al 1005 can use, while the min bandwidth allows to define a minimum
1095 frequency a task will always use. 1006 frequency a task will always use.
1096 1007
1097 When task group based utilization c 1008 When task group based utilization clamping is enabled, an eventually
1098 specified task-specific clamp value 1009 specified task-specific clamp value is constrained by the cgroup
1099 specified clamp value. Both minimum 1010 specified clamp value. Both minimum and maximum task clamping cannot
1100 be bigger than the corresponding cl 1011 be bigger than the corresponding clamping defined at task group level.
1101 1012
1102 If in doubt, say N. 1013 If in doubt, say N.
1103 1014
1104 config CGROUP_PIDS 1015 config CGROUP_PIDS
1105 bool "PIDs controller" 1016 bool "PIDs controller"
1106 help 1017 help
1107 Provides enforcement of process num 1018 Provides enforcement of process number limits in the scope of a
1108 cgroup. Any attempt to fork more pr 1019 cgroup. Any attempt to fork more processes than is allowed in the
1109 cgroup will fail. PIDs are fundamen 1020 cgroup will fail. PIDs are fundamentally a global resource because it
1110 is fairly trivial to reach PID exha 1021 is fairly trivial to reach PID exhaustion before you reach even a
1111 conservative kmemcg limit. As a res 1022 conservative kmemcg limit. As a result, it is possible to grind a
1112 system to halt without being limite 1023 system to halt without being limited by other cgroup policies. The
1113 PIDs controller is designed to stop 1024 PIDs controller is designed to stop this from happening.
1114 1025
1115 It should be noted that organisatio 1026 It should be noted that organisational operations (such as attaching
1116 to a cgroup hierarchy) will *not* b 1027 to a cgroup hierarchy) will *not* be blocked by the PIDs controller,
1117 since the PIDs limit only affects a 1028 since the PIDs limit only affects a process's ability to fork, not to
1118 attach to a cgroup. 1029 attach to a cgroup.
1119 1030
1120 config CGROUP_RDMA 1031 config CGROUP_RDMA
1121 bool "RDMA controller" 1032 bool "RDMA controller"
1122 help 1033 help
1123 Provides enforcement of RDMA resour 1034 Provides enforcement of RDMA resources defined by IB stack.
1124 It is fairly easy for consumers to 1035 It is fairly easy for consumers to exhaust RDMA resources, which
1125 can result into resource unavailabi 1036 can result into resource unavailability to other consumers.
1126 RDMA controller is designed to stop 1037 RDMA controller is designed to stop this from happening.
1127 Attaching processes with active RDM 1038 Attaching processes with active RDMA resources to the cgroup
1128 hierarchy is allowed even if can cr 1039 hierarchy is allowed even if can cross the hierarchy's limit.
1129 1040
1130 config CGROUP_FREEZER 1041 config CGROUP_FREEZER
1131 bool "Freezer controller" 1042 bool "Freezer controller"
1132 help 1043 help
1133 Provides a way to freeze and unfree 1044 Provides a way to freeze and unfreeze all tasks in a
1134 cgroup. 1045 cgroup.
1135 1046
1136 This option affects the ORIGINAL cg 1047 This option affects the ORIGINAL cgroup interface. The cgroup2 memory
1137 controller includes important in-ke 1048 controller includes important in-kernel memory consumers per default.
1138 1049
1139 If you're using cgroup2, say N. 1050 If you're using cgroup2, say N.
1140 1051
1141 config CGROUP_HUGETLB 1052 config CGROUP_HUGETLB
1142 bool "HugeTLB controller" 1053 bool "HugeTLB controller"
1143 depends on HUGETLB_PAGE 1054 depends on HUGETLB_PAGE
1144 select PAGE_COUNTER 1055 select PAGE_COUNTER
1145 default n 1056 default n
1146 help 1057 help
1147 Provides a cgroup controller for Hu 1058 Provides a cgroup controller for HugeTLB pages.
1148 When you enable this, you can put a 1059 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1149 The limit is enforced during page f 1060 The limit is enforced during page fault. Since HugeTLB doesn't
1150 support page reclaim, enforcing the 1061 support page reclaim, enforcing the limit at page fault time implies
1151 that, the application will get SIGB 1062 that, the application will get SIGBUS signal if it tries to access
1152 HugeTLB pages beyond its limit. Thi 1063 HugeTLB pages beyond its limit. This requires the application to know
1153 beforehand how much HugeTLB pages i 1064 beforehand how much HugeTLB pages it would require for its use. The
1154 control group is tracked in the thi 1065 control group is tracked in the third page lru pointer. This means
1155 that we cannot use the controller w 1066 that we cannot use the controller with huge page less than 3 pages.
1156 1067
1157 config CPUSETS 1068 config CPUSETS
1158 bool "Cpuset controller" 1069 bool "Cpuset controller"
1159 depends on SMP 1070 depends on SMP
1160 help 1071 help
1161 This option will let you create and 1072 This option will let you create and manage CPUSETs which
1162 allow dynamically partitioning a sy 1073 allow dynamically partitioning a system into sets of CPUs and
1163 Memory Nodes and assigning tasks to 1074 Memory Nodes and assigning tasks to run only within those sets.
1164 This is primarily useful on large S 1075 This is primarily useful on large SMP or NUMA systems.
1165 1076
1166 Say N if unsure. 1077 Say N if unsure.
1167 1078
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 1079 config PROC_PID_CPUSET
1182 bool "Include legacy /proc/<pid>/cpus 1080 bool "Include legacy /proc/<pid>/cpuset file"
1183 depends on CPUSETS 1081 depends on CPUSETS
1184 default y 1082 default y
1185 1083
1186 config CGROUP_DEVICE 1084 config CGROUP_DEVICE
1187 bool "Device controller" 1085 bool "Device controller"
1188 help 1086 help
1189 Provides a cgroup controller implem 1087 Provides a cgroup controller implementing whitelists for
1190 devices which a process in the cgro 1088 devices which a process in the cgroup can mknod or open.
1191 1089
1192 config CGROUP_CPUACCT 1090 config CGROUP_CPUACCT
1193 bool "Simple CPU accounting controlle 1091 bool "Simple CPU accounting controller"
1194 help 1092 help
1195 Provides a simple controller for mo 1093 Provides a simple controller for monitoring the
1196 total CPU consumed by the tasks in 1094 total CPU consumed by the tasks in a cgroup.
1197 1095
1198 config CGROUP_PERF 1096 config CGROUP_PERF
1199 bool "Perf controller" 1097 bool "Perf controller"
1200 depends on PERF_EVENTS 1098 depends on PERF_EVENTS
1201 help 1099 help
1202 This option extends the perf per-cp 1100 This option extends the perf per-cpu mode to restrict monitoring
1203 to threads which belong to the cgro 1101 to threads which belong to the cgroup specified and run on the
1204 designated cpu. Or this can be use 1102 designated cpu. Or this can be used to have cgroup ID in samples
1205 so that it can monitor performance 1103 so that it can monitor performance events among cgroups.
1206 1104
1207 Say N if unsure. 1105 Say N if unsure.
1208 1106
1209 config CGROUP_BPF 1107 config CGROUP_BPF
1210 bool "Support for eBPF programs attac 1108 bool "Support for eBPF programs attached to cgroups"
1211 depends on BPF_SYSCALL 1109 depends on BPF_SYSCALL
1212 select SOCK_CGROUP_DATA 1110 select SOCK_CGROUP_DATA
1213 help 1111 help
1214 Allow attaching eBPF programs to a 1112 Allow attaching eBPF programs to a cgroup using the bpf(2)
1215 syscall command BPF_PROG_ATTACH. 1113 syscall command BPF_PROG_ATTACH.
1216 1114
1217 In which context these programs are 1115 In which context these programs are accessed depends on the type
1218 of attachment. For instance, progra 1116 of attachment. For instance, programs that are attached using
1219 BPF_CGROUP_INET_INGRESS will be exe 1117 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
1220 inet sockets. 1118 inet sockets.
1221 1119
1222 config CGROUP_MISC 1120 config CGROUP_MISC
1223 bool "Misc resource controller" 1121 bool "Misc resource controller"
1224 default n 1122 default n
1225 help 1123 help
1226 Provides a controller for miscellan 1124 Provides a controller for miscellaneous resources on a host.
1227 1125
1228 Miscellaneous scalar resources are 1126 Miscellaneous scalar resources are the resources on the host system
1229 which cannot be abstracted like the 1127 which cannot be abstracted like the other cgroups. This controller
1230 tracks and limits the miscellaneous 1128 tracks and limits the miscellaneous resources used by a process
1231 attached to a cgroup hierarchy. 1129 attached to a cgroup hierarchy.
1232 1130
1233 For more information, please check 1131 For more information, please check misc cgroup section in
1234 /Documentation/admin-guide/cgroup-v 1132 /Documentation/admin-guide/cgroup-v2.rst.
1235 1133
1236 config CGROUP_DEBUG 1134 config CGROUP_DEBUG
1237 bool "Debug controller" 1135 bool "Debug controller"
1238 default n 1136 default n
1239 depends on DEBUG_KERNEL 1137 depends on DEBUG_KERNEL
1240 help 1138 help
1241 This option enables a simple contro 1139 This option enables a simple controller that exports
1242 debugging information about the cgr 1140 debugging information about the cgroups framework. This
1243 controller is for control cgroup de 1141 controller is for control cgroup debugging only. Its
1244 interfaces are not stable. 1142 interfaces are not stable.
1245 1143
1246 Say N. 1144 Say N.
1247 1145
1248 config SOCK_CGROUP_DATA 1146 config SOCK_CGROUP_DATA
1249 bool 1147 bool
1250 default n 1148 default n
1251 1149
1252 endif # CGROUPS 1150 endif # CGROUPS
1253 1151
1254 menuconfig NAMESPACES 1152 menuconfig NAMESPACES
1255 bool "Namespaces support" if EXPERT 1153 bool "Namespaces support" if EXPERT
1256 depends on MULTIUSER 1154 depends on MULTIUSER
1257 default !EXPERT 1155 default !EXPERT
1258 help 1156 help
1259 Provides the way to make tasks work 1157 Provides the way to make tasks work with different objects using
1260 the same id. For example same IPC i 1158 the same id. For example same IPC id may refer to different objects
1261 or same user id or pid may refer to 1159 or same user id or pid may refer to different tasks when used in
1262 different namespaces. 1160 different namespaces.
1263 1161
1264 if NAMESPACES 1162 if NAMESPACES
1265 1163
1266 config UTS_NS 1164 config UTS_NS
1267 bool "UTS namespace" 1165 bool "UTS namespace"
1268 default y 1166 default y
1269 help 1167 help
1270 In this namespace tasks see differe 1168 In this namespace tasks see different info provided with the
1271 uname() system call 1169 uname() system call
1272 1170
1273 config TIME_NS 1171 config TIME_NS
1274 bool "TIME namespace" 1172 bool "TIME namespace"
1275 depends on GENERIC_VDSO_TIME_NS 1173 depends on GENERIC_VDSO_TIME_NS
1276 default y 1174 default y
1277 help 1175 help
1278 In this namespace boottime and mono 1176 In this namespace boottime and monotonic clocks can be set.
1279 The time will keep going with the s 1177 The time will keep going with the same pace.
1280 1178
1281 config IPC_NS 1179 config IPC_NS
1282 bool "IPC namespace" 1180 bool "IPC namespace"
1283 depends on (SYSVIPC || POSIX_MQUEUE) 1181 depends on (SYSVIPC || POSIX_MQUEUE)
1284 default y 1182 default y
1285 help 1183 help
1286 In this namespace tasks work with I 1184 In this namespace tasks work with IPC ids which correspond to
1287 different IPC objects in different 1185 different IPC objects in different namespaces.
1288 1186
1289 config USER_NS 1187 config USER_NS
1290 bool "User namespace" 1188 bool "User namespace"
1291 default n 1189 default n
1292 help 1190 help
1293 This allows containers, i.e. vserve 1191 This allows containers, i.e. vservers, to use user namespaces
1294 to provide different user info for 1192 to provide different user info for different servers.
1295 1193
1296 When user namespaces are enabled in 1194 When user namespaces are enabled in the kernel it is
1297 recommended that the MEMCG option a 1195 recommended that the MEMCG option also be enabled and that
1298 user-space use the memory control g 1196 user-space use the memory control groups to limit the amount
1299 of memory a memory unprivileged use 1197 of memory a memory unprivileged users can use.
1300 1198
1301 If unsure, say N. 1199 If unsure, say N.
1302 1200
1303 config PID_NS 1201 config PID_NS
1304 bool "PID Namespaces" 1202 bool "PID Namespaces"
1305 default y 1203 default y
1306 help 1204 help
1307 Support process id namespaces. Thi 1205 Support process id namespaces. This allows having multiple
1308 processes with the same pid as long 1206 processes with the same pid as long as they are in different
1309 pid namespaces. This is a building 1207 pid namespaces. This is a building block of containers.
1310 1208
1311 config NET_NS 1209 config NET_NS
1312 bool "Network namespace" 1210 bool "Network namespace"
1313 depends on NET 1211 depends on NET
1314 default y 1212 default y
1315 help 1213 help
1316 Allow user space to create what app 1214 Allow user space to create what appear to be multiple instances
1317 of the network stack. 1215 of the network stack.
1318 1216
1319 endif # NAMESPACES 1217 endif # NAMESPACES
1320 1218
1321 config CHECKPOINT_RESTORE 1219 config CHECKPOINT_RESTORE
1322 bool "Checkpoint/restore support" 1220 bool "Checkpoint/restore support"
1323 depends on PROC_FS <<
1324 select PROC_CHILDREN 1221 select PROC_CHILDREN
1325 select KCMP 1222 select KCMP
1326 default n 1223 default n
1327 help 1224 help
1328 Enables additional kernel features 1225 Enables additional kernel features in a sake of checkpoint/restore.
1329 In particular it adds auxiliary prc 1226 In particular it adds auxiliary prctl codes to setup process text,
1330 data and heap segment sizes, and a 1227 data and heap segment sizes, and a few additional /proc filesystem
1331 entries. 1228 entries.
1332 1229
1333 If unsure, say N here. 1230 If unsure, say N here.
1334 1231
1335 config SCHED_AUTOGROUP 1232 config SCHED_AUTOGROUP
1336 bool "Automatic process group schedul 1233 bool "Automatic process group scheduling"
1337 select CGROUPS 1234 select CGROUPS
1338 select CGROUP_SCHED 1235 select CGROUP_SCHED
1339 select FAIR_GROUP_SCHED 1236 select FAIR_GROUP_SCHED
1340 help 1237 help
1341 This option optimizes the scheduler 1238 This option optimizes the scheduler for common desktop workloads by
1342 automatically creating and populati 1239 automatically creating and populating task groups. This separation
1343 of workloads isolates aggressive CP 1240 of workloads isolates aggressive CPU burners (like build jobs) from
1344 desktop applications. Task group a 1241 desktop applications. Task group autogeneration is currently based
1345 upon task session. 1242 upon task session.
1346 1243
>> 1244 config SYSFS_DEPRECATED
>> 1245 bool "Enable deprecated sysfs features to support old userspace tools"
>> 1246 depends on SYSFS
>> 1247 default n
>> 1248 help
>> 1249 This option adds code that switches the layout of the "block" class
>> 1250 devices, to not show up in /sys/class/block/, but only in
>> 1251 /sys/block/.
>> 1252
>> 1253 This switch is only active when the sysfs.deprecated=1 boot option is
>> 1254 passed or the SYSFS_DEPRECATED_V2 option is set.
>> 1255
>> 1256 This option allows new kernels to run on old distributions and tools,
>> 1257 which might get confused by /sys/class/block/. Since 2007/2008 all
>> 1258 major distributions and tools handle this just fine.
>> 1259
>> 1260 Recent distributions and userspace tools after 2009/2010 depend on
>> 1261 the existence of /sys/class/block/, and will not work with this
>> 1262 option enabled.
>> 1263
>> 1264 Only if you are using a new kernel on an old distribution, you might
>> 1265 need to say Y here.
>> 1266
>> 1267 config SYSFS_DEPRECATED_V2
>> 1268 bool "Enable deprecated sysfs features by default"
>> 1269 default n
>> 1270 depends on SYSFS
>> 1271 depends on SYSFS_DEPRECATED
>> 1272 help
>> 1273 Enable deprecated sysfs by default.
>> 1274
>> 1275 See the CONFIG_SYSFS_DEPRECATED option for more details about this
>> 1276 option.
>> 1277
>> 1278 Only if you are using a new kernel on an old distribution, you might
>> 1279 need to say Y here. Even then, odds are you would not need it
>> 1280 enabled, you can always pass the boot option if absolutely necessary.
>> 1281
1347 config RELAY 1282 config RELAY
1348 bool "Kernel->user space relay suppor 1283 bool "Kernel->user space relay support (formerly relayfs)"
1349 select IRQ_WORK 1284 select IRQ_WORK
1350 help 1285 help
1351 This option enables support for rel 1286 This option enables support for relay interface support in
1352 certain file systems (such as debug 1287 certain file systems (such as debugfs).
1353 It is designed to provide an effici 1288 It is designed to provide an efficient mechanism for tools and
1354 facilities to relay large amounts o 1289 facilities to relay large amounts of data from kernel space to
1355 user space. 1290 user space.
1356 1291
1357 If unsure, say N. 1292 If unsure, say N.
1358 1293
1359 config BLK_DEV_INITRD 1294 config BLK_DEV_INITRD
1360 bool "Initial RAM filesystem and RAM 1295 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1361 help 1296 help
1362 The initial RAM filesystem is a ram 1297 The initial RAM filesystem is a ramfs which is loaded by the
1363 boot loader (loadlin or lilo) and t 1298 boot loader (loadlin or lilo) and that is mounted as root
1364 before the normal boot procedure. I 1299 before the normal boot procedure. It is typically used to
1365 load modules needed to mount the "r 1300 load modules needed to mount the "real" root file system,
1366 etc. See <file:Documentation/admin- 1301 etc. See <file:Documentation/admin-guide/initrd.rst> for details.
1367 1302
1368 If RAM disk support (BLK_DEV_RAM) i 1303 If RAM disk support (BLK_DEV_RAM) is also included, this
1369 also enables initial RAM disk (init 1304 also enables initial RAM disk (initrd) support and adds
1370 15 Kbytes (more on some other archi 1305 15 Kbytes (more on some other architectures) to the kernel size.
1371 1306
1372 If unsure say Y. 1307 If unsure say Y.
1373 1308
1374 if BLK_DEV_INITRD 1309 if BLK_DEV_INITRD
1375 1310
1376 source "usr/Kconfig" 1311 source "usr/Kconfig"
1377 1312
1378 endif 1313 endif
1379 1314
1380 config BOOT_CONFIG 1315 config BOOT_CONFIG
1381 bool "Boot config support" 1316 bool "Boot config support"
1382 select BLK_DEV_INITRD if !BOOT_CONFIG !! 1317 select BLK_DEV_INITRD
1383 help 1318 help
1384 Extra boot config allows system adm 1319 Extra boot config allows system admin to pass a config file as
1385 complemental extension of kernel cm 1320 complemental extension of kernel cmdline when booting.
1386 The boot config file must be attach 1321 The boot config file must be attached at the end of initramfs
1387 with checksum, size and magic word. 1322 with checksum, size and magic word.
1388 See <file:Documentation/admin-guide 1323 See <file:Documentation/admin-guide/bootconfig.rst> for details.
1389 1324
1390 If unsure, say Y. 1325 If unsure, say Y.
1391 1326
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 1327 choice
1435 prompt "Compiler optimization level" 1328 prompt "Compiler optimization level"
1436 default CC_OPTIMIZE_FOR_PERFORMANCE 1329 default CC_OPTIMIZE_FOR_PERFORMANCE
1437 1330
1438 config CC_OPTIMIZE_FOR_PERFORMANCE 1331 config CC_OPTIMIZE_FOR_PERFORMANCE
1439 bool "Optimize for performance (-O2)" 1332 bool "Optimize for performance (-O2)"
1440 help 1333 help
1441 This is the default optimization le 1334 This is the default optimization level for the kernel, building
1442 with the "-O2" compiler flag for be 1335 with the "-O2" compiler flag for best performance and most
1443 helpful compile-time warnings. 1336 helpful compile-time warnings.
1444 1337
>> 1338 config CC_OPTIMIZE_FOR_PERFORMANCE_O3
>> 1339 bool "Optimize more for performance (-O3)"
>> 1340 depends on ARC
>> 1341 help
>> 1342 Choosing this option will pass "-O3" to your compiler to optimize
>> 1343 the kernel yet more for performance.
>> 1344
1445 config CC_OPTIMIZE_FOR_SIZE 1345 config CC_OPTIMIZE_FOR_SIZE
1446 bool "Optimize for size (-Os)" 1346 bool "Optimize for size (-Os)"
1447 help 1347 help
1448 Choosing this option will pass "-Os 1348 Choosing this option will pass "-Os" to your compiler resulting
1449 in a smaller kernel. 1349 in a smaller kernel.
1450 1350
1451 endchoice 1351 endchoice
1452 1352
1453 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1353 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1454 bool 1354 bool
1455 help 1355 help
1456 This requires that the arch annotat 1356 This requires that the arch annotates or otherwise protects
1457 its external entry points from bein 1357 its external entry points from being discarded. Linker scripts
1458 must also merge .text.*, .data.*, a 1358 must also merge .text.*, .data.*, and .bss.* correctly into
1459 output sections. Care must be taken 1359 output sections. Care must be taken not to pull in unrelated
1460 sections (e.g., '.text.init'). Typi 1360 sections (e.g., '.text.init'). Typically '.' in section names
1461 is used to distinguish them from la 1361 is used to distinguish them from label names / C identifiers.
1462 1362
1463 config LD_DEAD_CODE_DATA_ELIMINATION 1363 config LD_DEAD_CODE_DATA_ELIMINATION
1464 bool "Dead code and data elimination 1364 bool "Dead code and data elimination (EXPERIMENTAL)"
1465 depends on HAVE_LD_DEAD_CODE_DATA_ELI 1365 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1466 depends on EXPERT 1366 depends on EXPERT
1467 depends on $(cc-option,-ffunction-sec 1367 depends on $(cc-option,-ffunction-sections -fdata-sections)
1468 depends on $(ld-option,--gc-sections) 1368 depends on $(ld-option,--gc-sections)
1469 help 1369 help
1470 Enable this if you want to do dead 1370 Enable this if you want to do dead code and data elimination with
1471 the linker by compiling with -ffunc 1371 the linker by compiling with -ffunction-sections -fdata-sections,
1472 and linking with --gc-sections. 1372 and linking with --gc-sections.
1473 1373
1474 This can reduce on disk and in-memo 1374 This can reduce on disk and in-memory size of the kernel
1475 code and static data, particularly 1375 code and static data, particularly for small configs and
1476 on small systems. This has the poss 1376 on small systems. This has the possibility of introducing
1477 silently broken kernel if the requi 1377 silently broken kernel if the required annotations are not
1478 present. This option is not well te 1378 present. This option is not well tested yet, so use at your
1479 own risk. 1379 own risk.
1480 1380
1481 config LD_ORPHAN_WARN 1381 config LD_ORPHAN_WARN
1482 def_bool y 1382 def_bool y
1483 depends on ARCH_WANT_LD_ORPHAN_WARN 1383 depends on ARCH_WANT_LD_ORPHAN_WARN
>> 1384 depends on !LD_IS_LLD || LLD_VERSION >= 110000
1484 depends on $(ld-option,--orphan-handl 1385 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 1386
1493 config SYSCTL 1387 config SYSCTL
1494 bool 1388 bool
1495 1389
1496 config HAVE_UID16 1390 config HAVE_UID16
1497 bool 1391 bool
1498 1392
1499 config SYSCTL_EXCEPTION_TRACE 1393 config SYSCTL_EXCEPTION_TRACE
1500 bool 1394 bool
1501 help 1395 help
1502 Enable support for /proc/sys/debug/ 1396 Enable support for /proc/sys/debug/exception-trace.
1503 1397
1504 config SYSCTL_ARCH_UNALIGN_NO_WARN 1398 config SYSCTL_ARCH_UNALIGN_NO_WARN
1505 bool 1399 bool
1506 help 1400 help
1507 Enable support for /proc/sys/kernel 1401 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1508 Allows arch to define/use @no_unali 1402 Allows arch to define/use @no_unaligned_warning to possibly warn
1509 about unaligned access emulation go 1403 about unaligned access emulation going on under the hood.
1510 1404
1511 config SYSCTL_ARCH_UNALIGN_ALLOW 1405 config SYSCTL_ARCH_UNALIGN_ALLOW
1512 bool 1406 bool
1513 help 1407 help
1514 Enable support for /proc/sys/kernel 1408 Enable support for /proc/sys/kernel/unaligned-trap
1515 Allows arches to define/use @unalig 1409 Allows arches to define/use @unaligned_enabled to runtime toggle
1516 the unaligned access emulation. 1410 the unaligned access emulation.
1517 see arch/parisc/kernel/unaligned.c 1411 see arch/parisc/kernel/unaligned.c for reference
1518 1412
1519 config HAVE_PCSPKR_PLATFORM 1413 config HAVE_PCSPKR_PLATFORM
1520 bool 1414 bool
1521 1415
>> 1416 # interpreter that classic socket filters depend on
>> 1417 config BPF
>> 1418 bool
>> 1419
1522 menuconfig EXPERT 1420 menuconfig EXPERT
1523 bool "Configure standard kernel featu 1421 bool "Configure standard kernel features (expert users)"
1524 # Unhide debug options, to make the o 1422 # Unhide debug options, to make the on-by-default options visible
1525 select DEBUG_KERNEL 1423 select DEBUG_KERNEL
1526 help 1424 help
1527 This option allows certain base ker 1425 This option allows certain base kernel options and settings
1528 to be disabled or tweaked. This is 1426 to be disabled or tweaked. This is for specialized
1529 environments which can tolerate a " 1427 environments which can tolerate a "non-standard" kernel.
1530 Only use this if you really know wh 1428 Only use this if you really know what you are doing.
1531 1429
1532 config UID16 1430 config UID16
1533 bool "Enable 16-bit UID system calls" 1431 bool "Enable 16-bit UID system calls" if EXPERT
1534 depends on HAVE_UID16 && MULTIUSER 1432 depends on HAVE_UID16 && MULTIUSER
1535 default y 1433 default y
1536 help 1434 help
1537 This enables the legacy 16-bit UID 1435 This enables the legacy 16-bit UID syscall wrappers.
1538 1436
1539 config MULTIUSER 1437 config MULTIUSER
1540 bool "Multiple users, groups and capa 1438 bool "Multiple users, groups and capabilities support" if EXPERT
1541 default y 1439 default y
1542 help 1440 help
1543 This option enables support for non 1441 This option enables support for non-root users, groups and
1544 capabilities. 1442 capabilities.
1545 1443
1546 If you say N here, all processes wi 1444 If you say N here, all processes will run with UID 0, GID 0, and all
1547 possible capabilities. Saying N he 1445 possible capabilities. Saying N here also compiles out support for
1548 system calls related to UIDs, GIDs, 1446 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1549 setgid, and capset. 1447 setgid, and capset.
1550 1448
1551 If unsure, say Y here. 1449 If unsure, say Y here.
1552 1450
1553 config SGETMASK_SYSCALL 1451 config SGETMASK_SYSCALL
1554 bool "sgetmask/ssetmask syscalls supp 1452 bool "sgetmask/ssetmask syscalls support" if EXPERT
1555 default PARISC || M68K || PPC || MIPS !! 1453 def_bool PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH
1556 help 1454 help
1557 sys_sgetmask and sys_ssetmask are o 1455 sys_sgetmask and sys_ssetmask are obsolete system calls
1558 no longer supported in libc but sti 1456 no longer supported in libc but still enabled by default in some
1559 architectures. 1457 architectures.
1560 1458
1561 If unsure, leave the default option 1459 If unsure, leave the default option here.
1562 1460
1563 config SYSFS_SYSCALL 1461 config SYSFS_SYSCALL
1564 bool "Sysfs syscall support" if EXPER 1462 bool "Sysfs syscall support" if EXPERT
1565 default y 1463 default y
1566 help 1464 help
1567 sys_sysfs is an obsolete system cal 1465 sys_sysfs is an obsolete system call no longer supported in libc.
1568 Note that disabling this option is 1466 Note that disabling this option is more secure but might break
1569 compatibility with some systems. 1467 compatibility with some systems.
1570 1468
1571 If unsure say Y here. 1469 If unsure say Y here.
1572 1470
1573 config FHANDLE 1471 config FHANDLE
1574 bool "open by fhandle syscalls" if EX 1472 bool "open by fhandle syscalls" if EXPERT
1575 select EXPORTFS 1473 select EXPORTFS
1576 default y 1474 default y
1577 help 1475 help
1578 If you say Y here, a user level pro 1476 If you say Y here, a user level program will be able to map
1579 file names to handle and then later 1477 file names to handle and then later use the handle for
1580 different file system operations. T 1478 different file system operations. This is useful in implementing
1581 userspace file servers, which now t 1479 userspace file servers, which now track files using handles instead
1582 of names. The handle would remain t 1480 of names. The handle would remain the same even if file names
1583 get renamed. Enables open_by_handle 1481 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
1584 syscalls. 1482 syscalls.
1585 1483
1586 config POSIX_TIMERS 1484 config POSIX_TIMERS
1587 bool "Posix Clocks & timers" if EXPER 1485 bool "Posix Clocks & timers" if EXPERT
1588 default y 1486 default y
1589 help 1487 help
1590 This includes native support for PO 1488 This includes native support for POSIX timers to the kernel.
1591 Some embedded systems have no use f 1489 Some embedded systems have no use for them and therefore they
1592 can be configured out to reduce the 1490 can be configured out to reduce the size of the kernel image.
1593 1491
1594 When this option is disabled, the f 1492 When this option is disabled, the following syscalls won't be
1595 available: timer_create, timer_gett 1493 available: timer_create, timer_gettime: timer_getoverrun,
1596 timer_settime, timer_delete, clock_ 1494 timer_settime, timer_delete, clock_adjtime, getitimer,
1597 setitimer, alarm. Furthermore, the 1495 setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
1598 clock_getres and clock_nanosleep sy 1496 clock_getres and clock_nanosleep syscalls will be limited to
1599 CLOCK_REALTIME, CLOCK_MONOTONIC and 1497 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
1600 1498
1601 If unsure say y. 1499 If unsure say y.
1602 1500
1603 config PRINTK 1501 config PRINTK
1604 default y 1502 default y
1605 bool "Enable support for printk" if E 1503 bool "Enable support for printk" if EXPERT
1606 select IRQ_WORK 1504 select IRQ_WORK
1607 help 1505 help
1608 This option enables normal printk s 1506 This option enables normal printk support. Removing it
1609 eliminates most of the message stri 1507 eliminates most of the message strings from the kernel image
1610 and makes the kernel more or less s 1508 and makes the kernel more or less silent. As this makes it
1611 very difficult to diagnose system p 1509 very difficult to diagnose system problems, saying N here is
1612 strongly discouraged. 1510 strongly discouraged.
1613 1511
>> 1512 config PRINTK_NMI
>> 1513 def_bool y
>> 1514 depends on PRINTK
>> 1515 depends on HAVE_NMI
>> 1516
1614 config BUG 1517 config BUG
1615 bool "BUG() support" if EXPERT 1518 bool "BUG() support" if EXPERT
1616 default y 1519 default y
1617 help 1520 help
1618 Disabling this option eliminates su 1521 Disabling this option eliminates support for BUG and WARN, reducing
1619 the size of your kernel image and p 1522 the size of your kernel image and potentially quietly ignoring
1620 numerous fatal conditions. You shou 1523 numerous fatal conditions. You should only consider disabling this
1621 option for embedded systems with no 1524 option for embedded systems with no facilities for reporting errors.
1622 Just say Y. 1525 Just say Y.
1623 1526
1624 config ELF_CORE 1527 config ELF_CORE
1625 depends on COREDUMP 1528 depends on COREDUMP
1626 default y 1529 default y
1627 bool "Enable ELF core dumps" if EXPER 1530 bool "Enable ELF core dumps" if EXPERT
1628 help 1531 help
1629 Enable support for generating core 1532 Enable support for generating core dumps. Disabling saves about 4k.
1630 1533
1631 1534
1632 config PCSPKR_PLATFORM 1535 config PCSPKR_PLATFORM
1633 bool "Enable PC-Speaker support" if E 1536 bool "Enable PC-Speaker support" if EXPERT
1634 depends on HAVE_PCSPKR_PLATFORM 1537 depends on HAVE_PCSPKR_PLATFORM
1635 select I8253_LOCK 1538 select I8253_LOCK
1636 default y 1539 default y
1637 help 1540 help
1638 This option allows to disable the i 1541 This option allows to disable the internal PC-Speaker
1639 support, saving some memory. 1542 support, saving some memory.
1640 1543
1641 config BASE_SMALL !! 1544 config BASE_FULL
1642 bool "Enable smaller-sized data struc !! 1545 default y
>> 1546 bool "Enable full-sized data structures for core" if EXPERT
1643 help 1547 help
1644 Enabling this option reduces the si !! 1548 Disabling this option reduces the size of miscellaneous core
1645 kernel data structures. This saves 1549 kernel data structures. This saves memory on small machines,
1646 but may reduce performance. 1550 but may reduce performance.
1647 1551
1648 config FUTEX 1552 config FUTEX
1649 bool "Enable futex support" if EXPERT 1553 bool "Enable futex support" if EXPERT
1650 depends on !(SPARC32 && SMP) <<
1651 default y 1554 default y
1652 imply RT_MUTEXES 1555 imply RT_MUTEXES
1653 help 1556 help
1654 Disabling this option will cause th 1557 Disabling this option will cause the kernel to be built without
1655 support for "fast userspace mutexes 1558 support for "fast userspace mutexes". The resulting kernel may not
1656 run glibc-based applications correc 1559 run glibc-based applications correctly.
1657 1560
1658 config FUTEX_PI 1561 config FUTEX_PI
1659 bool 1562 bool
1660 depends on FUTEX && RT_MUTEXES 1563 depends on FUTEX && RT_MUTEXES
1661 default y 1564 default y
1662 1565
>> 1566 config HAVE_FUTEX_CMPXCHG
>> 1567 bool
>> 1568 depends on FUTEX
>> 1569 help
>> 1570 Architectures should select this if futex_atomic_cmpxchg_inatomic()
>> 1571 is implemented and always working. This removes a couple of runtime
>> 1572 checks.
>> 1573
1663 config EPOLL 1574 config EPOLL
1664 bool "Enable eventpoll support" if EX 1575 bool "Enable eventpoll support" if EXPERT
1665 default y 1576 default y
1666 help 1577 help
1667 Disabling this option will cause th 1578 Disabling this option will cause the kernel to be built without
1668 support for epoll family of system 1579 support for epoll family of system calls.
1669 1580
1670 config SIGNALFD 1581 config SIGNALFD
1671 bool "Enable signalfd() system call" 1582 bool "Enable signalfd() system call" if EXPERT
1672 default y 1583 default y
1673 help 1584 help
1674 Enable the signalfd() system call t 1585 Enable the signalfd() system call that allows to receive signals
1675 on a file descriptor. 1586 on a file descriptor.
1676 1587
1677 If unsure, say Y. 1588 If unsure, say Y.
1678 1589
1679 config TIMERFD 1590 config TIMERFD
1680 bool "Enable timerfd() system call" i 1591 bool "Enable timerfd() system call" if EXPERT
1681 default y 1592 default y
1682 help 1593 help
1683 Enable the timerfd() system call th 1594 Enable the timerfd() system call that allows to receive timer
1684 events on a file descriptor. 1595 events on a file descriptor.
1685 1596
1686 If unsure, say Y. 1597 If unsure, say Y.
1687 1598
1688 config EVENTFD 1599 config EVENTFD
1689 bool "Enable eventfd() system call" i 1600 bool "Enable eventfd() system call" if EXPERT
1690 default y 1601 default y
1691 help 1602 help
1692 Enable the eventfd() system call th 1603 Enable the eventfd() system call that allows to receive both
1693 kernel notification (ie. KAIO) or u 1604 kernel notification (ie. KAIO) or userspace notifications.
1694 1605
1695 If unsure, say Y. 1606 If unsure, say Y.
1696 1607
1697 config SHMEM 1608 config SHMEM
1698 bool "Use full shmem filesystem" if E 1609 bool "Use full shmem filesystem" if EXPERT
1699 default y 1610 default y
1700 depends on MMU 1611 depends on MMU
1701 help 1612 help
1702 The shmem is an internal filesystem 1613 The shmem is an internal filesystem used to manage shared memory.
1703 It is backed by swap and manages re 1614 It is backed by swap and manages resource limits. It is also exported
1704 to userspace as tmpfs if TMPFS is e 1615 to userspace as tmpfs if TMPFS is enabled. Disabling this
1705 option replaces shmem and tmpfs wit 1616 option replaces shmem and tmpfs with the much simpler ramfs code,
1706 which may be appropriate on small s 1617 which may be appropriate on small systems without swap.
1707 1618
1708 config AIO 1619 config AIO
1709 bool "Enable AIO support" if EXPERT 1620 bool "Enable AIO support" if EXPERT
1710 default y 1621 default y
1711 help 1622 help
1712 This option enables POSIX asynchron 1623 This option enables POSIX asynchronous I/O which may by used
1713 by some high performance threaded a 1624 by some high performance threaded applications. Disabling
1714 this option saves about 7k. 1625 this option saves about 7k.
1715 1626
1716 config IO_URING 1627 config IO_URING
1717 bool "Enable IO uring support" if EXP 1628 bool "Enable IO uring support" if EXPERT
1718 select IO_WQ 1629 select IO_WQ
1719 default y 1630 default y
1720 help 1631 help
1721 This option enables support for the 1632 This option enables support for the io_uring interface, enabling
1722 applications to submit and complete 1633 applications to submit and complete IO through submission and
1723 completion rings that are shared be 1634 completion rings that are shared between the kernel and application.
1724 1635
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 1636 config ADVISE_SYSCALLS
1739 bool "Enable madvise/fadvise syscalls 1637 bool "Enable madvise/fadvise syscalls" if EXPERT
1740 default y 1638 default y
1741 help 1639 help
1742 This option enables the madvise and 1640 This option enables the madvise and fadvise syscalls, used by
1743 applications to advise the kernel a 1641 applications to advise the kernel about their future memory or file
1744 usage, improving performance. If bu 1642 usage, improving performance. If building an embedded system where no
1745 applications use these syscalls, yo 1643 applications use these syscalls, you can disable this option to save
1746 space. 1644 space.
1747 1645
>> 1646 config HAVE_ARCH_USERFAULTFD_WP
>> 1647 bool
>> 1648 help
>> 1649 Arch has userfaultfd write protection support
>> 1650
>> 1651 config HAVE_ARCH_USERFAULTFD_MINOR
>> 1652 bool
>> 1653 help
>> 1654 Arch has userfaultfd minor fault support
>> 1655
1748 config MEMBARRIER 1656 config MEMBARRIER
1749 bool "Enable membarrier() system call 1657 bool "Enable membarrier() system call" if EXPERT
1750 default y 1658 default y
1751 help 1659 help
1752 Enable the membarrier() system call 1660 Enable the membarrier() system call that allows issuing memory
1753 barriers across all running threads 1661 barriers across all running threads, which can be used to distribute
1754 the cost of user-space memory barri 1662 the cost of user-space memory barriers asymmetrically by transforming
1755 pairs of memory barriers into pairs 1663 pairs of memory barriers into pairs consisting of membarrier() and a
1756 compiler barrier. 1664 compiler barrier.
1757 1665
1758 If unsure, say Y. 1666 If unsure, say Y.
1759 1667
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 1668 config KALLSYMS
1811 bool "Load all symbols for debugging/ 1669 bool "Load all symbols for debugging/ksymoops" if EXPERT
1812 default y 1670 default y
1813 help 1671 help
1814 Say Y here to let the kernel print 1672 Say Y here to let the kernel print out symbolic crash information and
1815 symbolic stack backtraces. This inc 1673 symbolic stack backtraces. This increases the size of the kernel
1816 somewhat, as all symbols have to be 1674 somewhat, as all symbols have to be loaded into the kernel image.
1817 1675
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 1676 config KALLSYMS_ALL
1832 bool "Include all symbols in kallsyms 1677 bool "Include all symbols in kallsyms"
1833 depends on DEBUG_KERNEL && KALLSYMS 1678 depends on DEBUG_KERNEL && KALLSYMS
1834 help 1679 help
1835 Normally kallsyms only contains the 1680 Normally kallsyms only contains the symbols of functions for nicer
1836 OOPS messages and backtraces (i.e., 1681 OOPS messages and backtraces (i.e., symbols from the text and inittext
1837 sections). This is sufficient for m !! 1682 sections). This is sufficient for most cases. And only in very rare
1838 enable kernel live patching, or oth !! 1683 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1839 when a debugger is used) all symbol !! 1684 names of variables from the data sections, etc).
1840 variables from the data sections, e <<
1841 1685
1842 This option makes sure that all sym 1686 This option makes sure that all symbols are loaded into the kernel
1843 image (i.e., symbols from all secti 1687 image (i.e., symbols from all sections) in cost of increased kernel
1844 size (depending on the kernel confi 1688 size (depending on the kernel configuration, it may be 300KiB or
1845 something like this). 1689 something like this).
1846 1690
1847 Say N unless you really need all sy !! 1691 Say N unless you really need all symbols.
1848 1692
1849 config KALLSYMS_ABSOLUTE_PERCPU 1693 config KALLSYMS_ABSOLUTE_PERCPU
1850 bool 1694 bool
1851 depends on KALLSYMS 1695 depends on KALLSYMS
1852 default X86_64 && SMP 1696 default X86_64 && SMP
1853 1697
>> 1698 config KALLSYMS_BASE_RELATIVE
>> 1699 bool
>> 1700 depends on KALLSYMS
>> 1701 default !IA64
>> 1702 help
>> 1703 Instead of emitting them as absolute values in the native word size,
>> 1704 emit the symbol references in the kallsyms table as 32-bit entries,
>> 1705 each containing a relative value in the range [base, base + U32_MAX]
>> 1706 or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either
>> 1707 an absolute value in the range [0, S32_MAX] or a relative value in the
>> 1708 range [base, base + S32_MAX], where base is the lowest relative symbol
>> 1709 address encountered in the image.
>> 1710
>> 1711 On 64-bit builds, this reduces the size of the address table by 50%,
>> 1712 but more importantly, it results in entries whose values are build
>> 1713 time constants, and no relocation pass is required at runtime to fix
>> 1714 up the entries based on the runtime load address of the kernel.
>> 1715
1854 # end of the "standard kernel features (exper 1716 # end of the "standard kernel features (expert users)" menu
1855 1717
>> 1718 # syscall, maps, verifier
>> 1719
>> 1720 config USERFAULTFD
>> 1721 bool "Enable userfaultfd() system call"
>> 1722 depends on MMU
>> 1723 help
>> 1724 Enable the userfaultfd() system call that allows to intercept and
>> 1725 handle page faults in userland.
>> 1726
1856 config ARCH_HAS_MEMBARRIER_CALLBACKS 1727 config ARCH_HAS_MEMBARRIER_CALLBACKS
1857 bool 1728 bool
1858 1729
1859 config ARCH_HAS_MEMBARRIER_SYNC_CORE 1730 config ARCH_HAS_MEMBARRIER_SYNC_CORE
1860 bool 1731 bool
1861 1732
>> 1733 config KCMP
>> 1734 bool "Enable kcmp() system call" if EXPERT
>> 1735 help
>> 1736 Enable the kernel resource comparison system call. It provides
>> 1737 user-space with the ability to compare two processes to see if they
>> 1738 share a common resource, such as a file descriptor or even virtual
>> 1739 memory space.
>> 1740
>> 1741 If unsure, say N.
>> 1742
>> 1743 config RSEQ
>> 1744 bool "Enable rseq() system call" if EXPERT
>> 1745 default y
>> 1746 depends on HAVE_RSEQ
>> 1747 select MEMBARRIER
>> 1748 help
>> 1749 Enable the restartable sequences system call. It provides a
>> 1750 user-space cache for the current CPU number value, which
>> 1751 speeds up getting the current CPU number from user-space,
>> 1752 as well as an ABI to speed up user-space operations on
>> 1753 per-CPU data.
>> 1754
>> 1755 If unsure, say Y.
>> 1756
>> 1757 config DEBUG_RSEQ
>> 1758 default n
>> 1759 bool "Enabled debugging of rseq() system call" if EXPERT
>> 1760 depends on RSEQ && DEBUG_KERNEL
>> 1761 help
>> 1762 Enable extra debugging checks for the rseq system call.
>> 1763
>> 1764 If unsure, say N.
>> 1765
>> 1766 config EMBEDDED
>> 1767 bool "Embedded system"
>> 1768 select EXPERT
>> 1769 help
>> 1770 This option should be enabled if compiling the kernel for
>> 1771 an embedded system so certain expert options are available
>> 1772 for configuration.
>> 1773
1862 config HAVE_PERF_EVENTS 1774 config HAVE_PERF_EVENTS
1863 bool 1775 bool
1864 help 1776 help
1865 See tools/perf/design.txt for detai 1777 See tools/perf/design.txt for details.
1866 1778
1867 config GUEST_PERF_EVENTS <<
1868 bool <<
1869 depends on HAVE_PERF_EVENTS <<
1870 <<
1871 config PERF_USE_VMALLOC 1779 config PERF_USE_VMALLOC
1872 bool 1780 bool
1873 help 1781 help
1874 See tools/perf/design.txt for detai 1782 See tools/perf/design.txt for details
1875 1783
>> 1784 config PC104
>> 1785 bool "PC/104 support" if EXPERT
>> 1786 help
>> 1787 Expose PC/104 form factor device drivers and options available for
>> 1788 selection and configuration. Enable this option if your target
>> 1789 machine has a PC/104 bus.
>> 1790
1876 menu "Kernel Performance Events And Counters" 1791 menu "Kernel Performance Events And Counters"
1877 1792
1878 config PERF_EVENTS 1793 config PERF_EVENTS
1879 bool "Kernel performance events and c 1794 bool "Kernel performance events and counters"
1880 default y if PROFILING 1795 default y if PROFILING
1881 depends on HAVE_PERF_EVENTS 1796 depends on HAVE_PERF_EVENTS
1882 select IRQ_WORK 1797 select IRQ_WORK
>> 1798 select SRCU
1883 help 1799 help
1884 Enable kernel support for various p 1800 Enable kernel support for various performance events provided
1885 by software and hardware. 1801 by software and hardware.
1886 1802
1887 Software events are supported eithe 1803 Software events are supported either built-in or via the
1888 use of generic tracepoints. 1804 use of generic tracepoints.
1889 1805
1890 Most modern CPUs support performanc 1806 Most modern CPUs support performance events via performance
1891 counter registers. These registers 1807 counter registers. These registers count the number of certain
1892 types of hw events: such as instruc 1808 types of hw events: such as instructions executed, cachemisses
1893 suffered, or branches mis-predicted 1809 suffered, or branches mis-predicted - without slowing down the
1894 kernel or applications. These regis 1810 kernel or applications. These registers can also trigger interrupts
1895 when a threshold number of events h 1811 when a threshold number of events have passed - and can thus be
1896 used to profile the code that runs 1812 used to profile the code that runs on that CPU.
1897 1813
1898 The Linux Performance Event subsyst 1814 The Linux Performance Event subsystem provides an abstraction of
1899 these software and hardware event c 1815 these software and hardware event capabilities, available via a
1900 system call and used by the "perf" 1816 system call and used by the "perf" utility in tools/perf/. It
1901 provides per task and per CPU count 1817 provides per task and per CPU counters, and it provides event
1902 capabilities on top of those. 1818 capabilities on top of those.
1903 1819
1904 Say Y if unsure. 1820 Say Y if unsure.
1905 1821
1906 config DEBUG_PERF_USE_VMALLOC 1822 config DEBUG_PERF_USE_VMALLOC
1907 default n 1823 default n
1908 bool "Debug: use vmalloc to back perf 1824 bool "Debug: use vmalloc to back perf mmap() buffers"
1909 depends on PERF_EVENTS && DEBUG_KERNE 1825 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
1910 select PERF_USE_VMALLOC 1826 select PERF_USE_VMALLOC
1911 help 1827 help
1912 Use vmalloc memory to back perf mma 1828 Use vmalloc memory to back perf mmap() buffers.
1913 1829
1914 Mostly useful for debugging the vma 1830 Mostly useful for debugging the vmalloc code on platforms
1915 that don't require it. 1831 that don't require it.
1916 1832
1917 Say N if unsure. 1833 Say N if unsure.
1918 1834
1919 endmenu 1835 endmenu
1920 1836
>> 1837 config VM_EVENT_COUNTERS
>> 1838 default y
>> 1839 bool "Enable VM event counters for /proc/vmstat" if EXPERT
>> 1840 help
>> 1841 VM event counters are needed for event counts to be shown.
>> 1842 This option allows the disabling of the VM event counters
>> 1843 on EXPERT systems. /proc/vmstat will only show page counts
>> 1844 if VM event counters are disabled.
>> 1845
>> 1846 config SLUB_DEBUG
>> 1847 default y
>> 1848 bool "Enable SLUB debugging support" if EXPERT
>> 1849 depends on SLUB && SYSFS
>> 1850 help
>> 1851 SLUB has extensive debug support features. Disabling these can
>> 1852 result in significant savings in code size. This also disables
>> 1853 SLUB sysfs support. /sys/slab will not exist and there will be
>> 1854 no support for cache validation etc.
>> 1855
>> 1856 config COMPAT_BRK
>> 1857 bool "Disable heap randomization"
>> 1858 default y
>> 1859 help
>> 1860 Randomizing heap placement makes heap exploits harder, but it
>> 1861 also breaks ancient binaries (including anything libc5 based).
>> 1862 This option changes the bootup default to heap randomization
>> 1863 disabled, and can be overridden at runtime by setting
>> 1864 /proc/sys/kernel/randomize_va_space to 2.
>> 1865
>> 1866 On non-ancient distros (post-2000 ones) N is usually a safe choice.
>> 1867
>> 1868 choice
>> 1869 prompt "Choose SLAB allocator"
>> 1870 default SLUB
>> 1871 help
>> 1872 This option allows to select a slab allocator.
>> 1873
>> 1874 config SLAB
>> 1875 bool "SLAB"
>> 1876 select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 1877 help
>> 1878 The regular slab allocator that is established and known to work
>> 1879 well in all environments. It organizes cache hot objects in
>> 1880 per cpu and per node queues.
>> 1881
>> 1882 config SLUB
>> 1883 bool "SLUB (Unqueued Allocator)"
>> 1884 select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 1885 help
>> 1886 SLUB is a slab allocator that minimizes cache line usage
>> 1887 instead of managing queues of cached objects (SLAB approach).
>> 1888 Per cpu caching is realized using slabs of objects instead
>> 1889 of queues of objects. SLUB can use memory efficiently
>> 1890 and has enhanced diagnostics. SLUB is the default choice for
>> 1891 a slab allocator.
>> 1892
>> 1893 config SLOB
>> 1894 depends on EXPERT
>> 1895 bool "SLOB (Simple Allocator)"
>> 1896 help
>> 1897 SLOB replaces the stock allocator with a drastically simpler
>> 1898 allocator. SLOB is generally more space efficient but
>> 1899 does not perform as well on large systems.
>> 1900
>> 1901 endchoice
>> 1902
>> 1903 config SLAB_MERGE_DEFAULT
>> 1904 bool "Allow slab caches to be merged"
>> 1905 default y
>> 1906 help
>> 1907 For reduced kernel memory fragmentation, slab caches can be
>> 1908 merged when they share the same size and other characteristics.
>> 1909 This carries a risk of kernel heap overflows being able to
>> 1910 overwrite objects from merged caches (and more easily control
>> 1911 cache layout), which makes such heap attacks easier to exploit
>> 1912 by attackers. By keeping caches unmerged, these kinds of exploits
>> 1913 can usually only damage objects in the same cache. To disable
>> 1914 merging at runtime, "slab_nomerge" can be passed on the kernel
>> 1915 command line.
>> 1916
>> 1917 config SLAB_FREELIST_RANDOM
>> 1918 bool "Randomize slab freelist"
>> 1919 depends on SLAB || SLUB
>> 1920 help
>> 1921 Randomizes the freelist order used on creating new pages. This
>> 1922 security feature reduces the predictability of the kernel slab
>> 1923 allocator against heap overflows.
>> 1924
>> 1925 config SLAB_FREELIST_HARDENED
>> 1926 bool "Harden slab freelist metadata"
>> 1927 depends on SLAB || SLUB
>> 1928 help
>> 1929 Many kernel heap attacks try to target slab cache metadata and
>> 1930 other infrastructure. This options makes minor performance
>> 1931 sacrifices to harden the kernel slab allocator against common
>> 1932 freelist exploit methods. Some slab implementations have more
>> 1933 sanity-checking than others. This option is most effective with
>> 1934 CONFIG_SLUB.
>> 1935
>> 1936 config SHUFFLE_PAGE_ALLOCATOR
>> 1937 bool "Page allocator randomization"
>> 1938 default SLAB_FREELIST_RANDOM && ACPI_NUMA
>> 1939 help
>> 1940 Randomization of the page allocator improves the average
>> 1941 utilization of a direct-mapped memory-side-cache. See section
>> 1942 5.2.27 Heterogeneous Memory Attribute Table (HMAT) in the ACPI
>> 1943 6.2a specification for an example of how a platform advertises
>> 1944 the presence of a memory-side-cache. There are also incidental
>> 1945 security benefits as it reduces the predictability of page
>> 1946 allocations to compliment SLAB_FREELIST_RANDOM, but the
>> 1947 default granularity of shuffling on the "MAX_ORDER - 1" i.e,
>> 1948 10th order of pages is selected based on cache utilization
>> 1949 benefits on x86.
>> 1950
>> 1951 While the randomization improves cache utilization it may
>> 1952 negatively impact workloads on platforms without a cache. For
>> 1953 this reason, by default, the randomization is enabled only
>> 1954 after runtime detection of a direct-mapped memory-side-cache.
>> 1955 Otherwise, the randomization may be force enabled with the
>> 1956 'page_alloc.shuffle' kernel command line parameter.
>> 1957
>> 1958 Say Y if unsure.
>> 1959
>> 1960 config SLUB_CPU_PARTIAL
>> 1961 default y
>> 1962 depends on SLUB && SMP
>> 1963 bool "SLUB per cpu partial cache"
>> 1964 help
>> 1965 Per cpu partial caches accelerate objects allocation and freeing
>> 1966 that is local to a processor at the price of more indeterminism
>> 1967 in the latency of the free. On overflow these caches will be cleared
>> 1968 which requires the taking of locks that may cause latency spikes.
>> 1969 Typically one would choose no for a realtime system.
>> 1970
>> 1971 config MMAP_ALLOW_UNINITIALIZED
>> 1972 bool "Allow mmapped anonymous memory to be uninitialized"
>> 1973 depends on EXPERT && !MMU
>> 1974 default n
>> 1975 help
>> 1976 Normally, and according to the Linux spec, anonymous memory obtained
>> 1977 from mmap() has its contents cleared before it is passed to
>> 1978 userspace. Enabling this config option allows you to request that
>> 1979 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
>> 1980 providing a huge performance boost. If this option is not enabled,
>> 1981 then the flag will be ignored.
>> 1982
>> 1983 This is taken advantage of by uClibc's malloc(), and also by
>> 1984 ELF-FDPIC binfmt's brk and stack allocator.
>> 1985
>> 1986 Because of the obvious security issues, this option should only be
>> 1987 enabled on embedded devices where you control what is run in
>> 1988 userspace. Since that isn't generally a problem on no-MMU systems,
>> 1989 it is normally safe to say Y here.
>> 1990
>> 1991 See Documentation/admin-guide/mm/nommu-mmap.rst for more information.
>> 1992
1921 config SYSTEM_DATA_VERIFICATION 1993 config SYSTEM_DATA_VERIFICATION
1922 def_bool n 1994 def_bool n
1923 select SYSTEM_TRUSTED_KEYRING 1995 select SYSTEM_TRUSTED_KEYRING
1924 select KEYS 1996 select KEYS
1925 select CRYPTO 1997 select CRYPTO
1926 select CRYPTO_RSA 1998 select CRYPTO_RSA
1927 select ASYMMETRIC_KEY_TYPE 1999 select ASYMMETRIC_KEY_TYPE
1928 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 2000 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1929 select ASN1 2001 select ASN1
1930 select OID_REGISTRY 2002 select OID_REGISTRY
1931 select X509_CERTIFICATE_PARSER 2003 select X509_CERTIFICATE_PARSER
1932 select PKCS7_MESSAGE_PARSER 2004 select PKCS7_MESSAGE_PARSER
1933 help 2005 help
1934 Provide PKCS#7 message verification 2006 Provide PKCS#7 message verification using the contents of the system
1935 trusted keyring to provide public k 2007 trusted keyring to provide public keys. This then can be used for
1936 module verification, kexec image ve 2008 module verification, kexec image verification and firmware blob
1937 verification. 2009 verification.
1938 2010
1939 config PROFILING 2011 config PROFILING
1940 bool "Profiling support" 2012 bool "Profiling support"
1941 help 2013 help
1942 Say Y here to enable the extended p 2014 Say Y here to enable the extended profiling support mechanisms used
1943 by profilers. 2015 by profilers.
1944 2016
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 # 2017 #
1987 # Place an empty function call at each tracep 2018 # Place an empty function call at each tracepoint site. Can be
1988 # dynamically changed for a probe function. 2019 # dynamically changed for a probe function.
1989 # 2020 #
1990 config TRACEPOINTS 2021 config TRACEPOINTS
1991 bool 2022 bool
1992 2023
1993 source "kernel/Kconfig.kexec" <<
1994 <<
1995 endmenu # General setup 2024 endmenu # General setup
1996 2025
1997 source "arch/Kconfig" 2026 source "arch/Kconfig"
1998 2027
1999 config RT_MUTEXES 2028 config RT_MUTEXES
2000 bool 2029 bool
2001 default y if PREEMPT_RT !! 2030
>> 2031 config BASE_SMALL
>> 2032 int
>> 2033 default 0 if BASE_FULL
>> 2034 default 1 if !BASE_FULL
2002 2035
2003 config MODULE_SIG_FORMAT 2036 config MODULE_SIG_FORMAT
2004 def_bool n 2037 def_bool n
2005 select SYSTEM_DATA_VERIFICATION 2038 select SYSTEM_DATA_VERIFICATION
2006 2039
2007 source "kernel/module/Kconfig" !! 2040 menuconfig MODULES
>> 2041 bool "Enable loadable module support"
>> 2042 modules
>> 2043 help
>> 2044 Kernel modules are small pieces of compiled code which can
>> 2045 be inserted in the running kernel, rather than being
>> 2046 permanently built into the kernel. You use the "modprobe"
>> 2047 tool to add (and sometimes remove) them. If you say Y here,
>> 2048 many parts of the kernel can be built as modules (by
>> 2049 answering M instead of Y where indicated): this is most
>> 2050 useful for infrequently used options which are not required
>> 2051 for booting. For more information, see the man pages for
>> 2052 modprobe, lsmod, modinfo, insmod and rmmod.
>> 2053
>> 2054 If you say Y here, you will need to run "make
>> 2055 modules_install" to put the modules under /lib/modules/
>> 2056 where modprobe can find them (you may need to be root to do
>> 2057 this).
>> 2058
>> 2059 If unsure, say Y.
>> 2060
>> 2061 if MODULES
>> 2062
>> 2063 config MODULE_FORCE_LOAD
>> 2064 bool "Forced module loading"
>> 2065 default n
>> 2066 help
>> 2067 Allow loading of modules without version information (ie. modprobe
>> 2068 --force). Forced module loading sets the 'F' (forced) taint flag and
>> 2069 is usually a really bad idea.
>> 2070
>> 2071 config MODULE_UNLOAD
>> 2072 bool "Module unloading"
>> 2073 help
>> 2074 Without this option you will not be able to unload any
>> 2075 modules (note that some modules may not be unloadable
>> 2076 anyway), which makes your kernel smaller, faster
>> 2077 and simpler. If unsure, say Y.
>> 2078
>> 2079 config MODULE_FORCE_UNLOAD
>> 2080 bool "Forced module unloading"
>> 2081 depends on MODULE_UNLOAD
>> 2082 help
>> 2083 This option allows you to force a module to unload, even if the
>> 2084 kernel believes it is unsafe: the kernel will remove the module
>> 2085 without waiting for anyone to stop using it (using the -f option to
>> 2086 rmmod). This is mainly for kernel developers and desperate users.
>> 2087 If unsure, say N.
>> 2088
>> 2089 config MODVERSIONS
>> 2090 bool "Module versioning support"
>> 2091 help
>> 2092 Usually, you have to use modules compiled with your kernel.
>> 2093 Saying Y here makes it sometimes possible to use modules
>> 2094 compiled for different kernels, by adding enough information
>> 2095 to the modules to (hopefully) spot any changes which would
>> 2096 make them incompatible with the kernel you are running. If
>> 2097 unsure, say N.
>> 2098
>> 2099 config ASM_MODVERSIONS
>> 2100 bool
>> 2101 default HAVE_ASM_MODVERSIONS && MODVERSIONS
>> 2102 help
>> 2103 This enables module versioning for exported symbols also from
>> 2104 assembly. This can be enabled only when the target architecture
>> 2105 supports it.
>> 2106
>> 2107 config MODULE_REL_CRCS
>> 2108 bool
>> 2109 depends on MODVERSIONS
>> 2110
>> 2111 config MODULE_SRCVERSION_ALL
>> 2112 bool "Source checksum for all modules"
>> 2113 help
>> 2114 Modules which contain a MODULE_VERSION get an extra "srcversion"
>> 2115 field inserted into their modinfo section, which contains a
>> 2116 sum of the source files which made it. This helps maintainers
>> 2117 see exactly which source was used to build a module (since
>> 2118 others sometimes change the module source without updating
>> 2119 the version). With this option, such a "srcversion" field
>> 2120 will be created for all modules. If unsure, say N.
>> 2121
>> 2122 config MODULE_SIG
>> 2123 bool "Module signature verification"
>> 2124 select MODULE_SIG_FORMAT
>> 2125 help
>> 2126 Check modules for valid signatures upon load: the signature
>> 2127 is simply appended to the module. For more information see
>> 2128 <file:Documentation/admin-guide/module-signing.rst>.
>> 2129
>> 2130 Note that this option adds the OpenSSL development packages as a
>> 2131 kernel build dependency so that the signing tool can use its crypto
>> 2132 library.
>> 2133
>> 2134 You should enable this option if you wish to use either
>> 2135 CONFIG_SECURITY_LOCKDOWN_LSM or lockdown functionality imposed via
>> 2136 another LSM - otherwise unsigned modules will be loadable regardless
>> 2137 of the lockdown policy.
>> 2138
>> 2139 !!!WARNING!!! If you enable this option, you MUST make sure that the
>> 2140 module DOES NOT get stripped after being signed. This includes the
>> 2141 debuginfo strip done by some packagers (such as rpmbuild) and
>> 2142 inclusion into an initramfs that wants the module size reduced.
>> 2143
>> 2144 config MODULE_SIG_FORCE
>> 2145 bool "Require modules to be validly signed"
>> 2146 depends on MODULE_SIG
>> 2147 help
>> 2148 Reject unsigned modules or signed modules for which we don't have a
>> 2149 key. Without this, such modules will simply taint the kernel.
>> 2150
>> 2151 config MODULE_SIG_ALL
>> 2152 bool "Automatically sign all modules"
>> 2153 default y
>> 2154 depends on MODULE_SIG || IMA_APPRAISE_MODSIG
>> 2155 help
>> 2156 Sign all modules during make modules_install. Without this option,
>> 2157 modules must be signed manually, using the scripts/sign-file tool.
>> 2158
>> 2159 comment "Do not forget to sign required modules with scripts/sign-file"
>> 2160 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
>> 2161
>> 2162 choice
>> 2163 prompt "Which hash algorithm should modules be signed with?"
>> 2164 depends on MODULE_SIG || IMA_APPRAISE_MODSIG
>> 2165 help
>> 2166 This determines which sort of hashing algorithm will be used during
>> 2167 signature generation. This algorithm _must_ be built into the kernel
>> 2168 directly so that signature verification can take place. It is not
>> 2169 possible to load a signed module containing the algorithm to check
>> 2170 the signature on that module.
>> 2171
>> 2172 config MODULE_SIG_SHA1
>> 2173 bool "Sign modules with SHA-1"
>> 2174 select CRYPTO_SHA1
>> 2175
>> 2176 config MODULE_SIG_SHA224
>> 2177 bool "Sign modules with SHA-224"
>> 2178 select CRYPTO_SHA256
>> 2179
>> 2180 config MODULE_SIG_SHA256
>> 2181 bool "Sign modules with SHA-256"
>> 2182 select CRYPTO_SHA256
>> 2183
>> 2184 config MODULE_SIG_SHA384
>> 2185 bool "Sign modules with SHA-384"
>> 2186 select CRYPTO_SHA512
>> 2187
>> 2188 config MODULE_SIG_SHA512
>> 2189 bool "Sign modules with SHA-512"
>> 2190 select CRYPTO_SHA512
>> 2191
>> 2192 endchoice
>> 2193
>> 2194 config MODULE_SIG_HASH
>> 2195 string
>> 2196 depends on MODULE_SIG || IMA_APPRAISE_MODSIG
>> 2197 default "sha1" if MODULE_SIG_SHA1
>> 2198 default "sha224" if MODULE_SIG_SHA224
>> 2199 default "sha256" if MODULE_SIG_SHA256
>> 2200 default "sha384" if MODULE_SIG_SHA384
>> 2201 default "sha512" if MODULE_SIG_SHA512
>> 2202
>> 2203 choice
>> 2204 prompt "Module compression mode"
>> 2205 help
>> 2206 This option allows you to choose the algorithm which will be used to
>> 2207 compress modules when 'make modules_install' is run. (or, you can
>> 2208 choose to not compress modules at all.)
>> 2209
>> 2210 External modules will also be compressed in the same way during the
>> 2211 installation.
>> 2212
>> 2213 For modules inside an initrd or initramfs, it's more efficient to
>> 2214 compress the whole initrd or initramfs instead.
>> 2215
>> 2216 This is fully compatible with signed modules.
>> 2217
>> 2218 Please note that the tool used to load modules needs to support the
>> 2219 corresponding algorithm. module-init-tools MAY support gzip, and kmod
>> 2220 MAY support gzip, xz and zstd.
>> 2221
>> 2222 Your build system needs to provide the appropriate compression tool
>> 2223 to compress the modules.
>> 2224
>> 2225 If in doubt, select 'None'.
>> 2226
>> 2227 config MODULE_COMPRESS_NONE
>> 2228 bool "None"
>> 2229 help
>> 2230 Do not compress modules. The installed modules are suffixed
>> 2231 with .ko.
>> 2232
>> 2233 config MODULE_COMPRESS_GZIP
>> 2234 bool "GZIP"
>> 2235 help
>> 2236 Compress modules with GZIP. The installed modules are suffixed
>> 2237 with .ko.gz.
>> 2238
>> 2239 config MODULE_COMPRESS_XZ
>> 2240 bool "XZ"
>> 2241 help
>> 2242 Compress modules with XZ. The installed modules are suffixed
>> 2243 with .ko.xz.
>> 2244
>> 2245 config MODULE_COMPRESS_ZSTD
>> 2246 bool "ZSTD"
>> 2247 help
>> 2248 Compress modules with ZSTD. The installed modules are suffixed
>> 2249 with .ko.zst.
>> 2250
>> 2251 endchoice
>> 2252
>> 2253 config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
>> 2254 bool "Allow loading of modules with missing namespace imports"
>> 2255 help
>> 2256 Symbols exported with EXPORT_SYMBOL_NS*() are considered exported in
>> 2257 a namespace. A module that makes use of a symbol exported with such a
>> 2258 namespace is required to import the namespace via MODULE_IMPORT_NS().
>> 2259 There is no technical reason to enforce correct namespace imports,
>> 2260 but it creates consistency between symbols defining namespaces and
>> 2261 users importing namespaces they make use of. This option relaxes this
>> 2262 requirement and lifts the enforcement when loading a module.
>> 2263
>> 2264 If unsure, say N.
>> 2265
>> 2266 config MODPROBE_PATH
>> 2267 string "Path to modprobe binary"
>> 2268 default "/sbin/modprobe"
>> 2269 help
>> 2270 When kernel code requests a module, it does so by calling
>> 2271 the "modprobe" userspace utility. This option allows you to
>> 2272 set the path where that binary is found. This can be changed
>> 2273 at runtime via the sysctl file
>> 2274 /proc/sys/kernel/modprobe. Setting this to the empty string
>> 2275 removes the kernel's ability to request modules (but
>> 2276 userspace can still load modules explicitly).
>> 2277
>> 2278 config TRIM_UNUSED_KSYMS
>> 2279 bool "Trim unused exported kernel symbols" if EXPERT
>> 2280 depends on !COMPILE_TEST
>> 2281 help
>> 2282 The kernel and some modules make many symbols available for
>> 2283 other modules to use via EXPORT_SYMBOL() and variants. Depending
>> 2284 on the set of modules being selected in your kernel configuration,
>> 2285 many of those exported symbols might never be used.
>> 2286
>> 2287 This option allows for unused exported symbols to be dropped from
>> 2288 the build. In turn, this provides the compiler more opportunities
>> 2289 (especially when using LTO) for optimizing the code and reducing
>> 2290 binary size. This might have some security advantages as well.
>> 2291
>> 2292 If unsure, or if you need to build out-of-tree modules, say N.
>> 2293
>> 2294 config UNUSED_KSYMS_WHITELIST
>> 2295 string "Whitelist of symbols to keep in ksymtab"
>> 2296 depends on TRIM_UNUSED_KSYMS
>> 2297 help
>> 2298 By default, all unused exported symbols will be un-exported from the
>> 2299 build when TRIM_UNUSED_KSYMS is selected.
>> 2300
>> 2301 UNUSED_KSYMS_WHITELIST allows to whitelist symbols that must be kept
>> 2302 exported at all times, even in absence of in-tree users. The value to
>> 2303 set here is the path to a text file containing the list of symbols,
>> 2304 one per line. The path can be absolute, or relative to the kernel
>> 2305 source tree.
>> 2306
>> 2307 endif # MODULES
>> 2308
>> 2309 config MODULES_TREE_LOOKUP
>> 2310 def_bool y
>> 2311 depends on PERF_EVENTS || TRACING || CFI_CLANG
2008 2312
2009 config INIT_ALL_POSSIBLE 2313 config INIT_ALL_POSSIBLE
2010 bool 2314 bool
2011 help 2315 help
2012 Back when each arch used to define 2316 Back when each arch used to define their own cpu_online_mask and
2013 cpu_possible_mask, some of them cho 2317 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
2014 with all 1s, and others with all 0s 2318 with all 1s, and others with all 0s. When they were centralised,
2015 it was better to provide this optio 2319 it was better to provide this option than to break all the archs
2016 and have several arch maintainers p 2320 and have several arch maintainers pursuing me down dark alleys.
2017 2321
2018 source "block/Kconfig" 2322 source "block/Kconfig"
2019 2323
2020 config PREEMPT_NOTIFIERS 2324 config PREEMPT_NOTIFIERS
2021 bool 2325 bool
2022 2326
2023 config PADATA 2327 config PADATA
2024 depends on SMP 2328 depends on SMP
2025 bool 2329 bool
2026 2330
2027 config ASN1 2331 config ASN1
2028 tristate 2332 tristate
2029 help 2333 help
2030 Build a simple ASN.1 grammar compil 2334 Build a simple ASN.1 grammar compiler that produces a bytecode output
2031 that can be interpreted by the ASN. 2335 that can be interpreted by the ASN.1 stream decoder and used to
2032 inform it as to what tags are to be 2336 inform it as to what tags are to be expected in a stream and what
2033 functions to call on what tags. 2337 functions to call on what tags.
2034 2338
2035 source "kernel/Kconfig.locks" 2339 source "kernel/Kconfig.locks"
2036 2340
2037 config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 2341 config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
2038 bool <<
2039 <<
2040 config ARCH_HAS_PREPARE_SYNC_CORE_CMD <<
2041 bool 2342 bool
2042 2343
2043 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2344 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
2044 bool 2345 bool
2045 2346
2046 # It may be useful for an architecture to ove 2347 # It may be useful for an architecture to override the definitions of the
2047 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() ma 2348 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h>
2048 # and the COMPAT_ variants in <linux/compat.h 2349 # and the COMPAT_ variants in <linux/compat.h>, in particular to use a
2049 # different calling convention for syscalls. 2350 # different calling convention for syscalls. They can also override the
2050 # macros for not-implemented syscalls in kern 2351 # macros for not-implemented syscalls in kernel/sys_ni.c and
2051 # kernel/time/posix-stubs.c. All these overri 2352 # kernel/time/posix-stubs.c. All these overrides need to be available in
2052 # <asm/syscall_wrapper.h>. 2353 # <asm/syscall_wrapper.h>.
2053 config ARCH_HAS_SYSCALL_WRAPPER 2354 config ARCH_HAS_SYSCALL_WRAPPER
2054 def_bool n 2355 def_bool n
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