1 # SPDX-License-Identifier: GPL-2.0-only 1 # SPDX-License-Identifier: GPL-2.0-only
>> 2 config DEFCONFIG_LIST
>> 3 string
>> 4 depends on !UML
>> 5 option defconfig_list
>> 6 default "/lib/modules/$(shell,uname -r)/.config"
>> 7 default "/etc/kernel-config"
>> 8 default "/boot/config-$(shell,uname -r)"
>> 9 default "arch/$(SRCARCH)/configs/$(KBUILD_DEFCONFIG)"
>> 10
2 config CC_VERSION_TEXT 11 config CC_VERSION_TEXT
3 string 12 string
4 default "$(CC_VERSION_TEXT)" 13 default "$(CC_VERSION_TEXT)"
5 help 14 help
6 This is used in unclear ways: 15 This is used in unclear ways:
7 16
8 - Re-run Kconfig when the compiler i 17 - Re-run Kconfig when the compiler is updated
9 The 'default' property references 18 The 'default' property references the environment variable,
10 CC_VERSION_TEXT so it is recorded 19 CC_VERSION_TEXT so it is recorded in include/config/auto.conf.cmd.
11 When the compiler is updated, Kcon 20 When the compiler is updated, Kconfig will be invoked.
12 21
13 - Ensure full rebuild when the compi 22 - Ensure full rebuild when the compiler is updated
14 include/linux/compiler-version.h c 23 include/linux/compiler-version.h contains this option in the comment
15 line so fixdep adds include/config !! 24 line so fixdep adds include/config/cc/version/text.h into the
16 auto-generated dependency. When th 25 auto-generated dependency. When the compiler is updated, syncconfig
17 will touch it and then every file 26 will touch it and then every file will be rebuilt.
18 27
19 config CC_IS_GCC 28 config CC_IS_GCC
20 def_bool $(success,test "$(cc-name)" = 29 def_bool $(success,test "$(cc-name)" = GCC)
21 30
22 config GCC_VERSION 31 config GCC_VERSION
23 int 32 int
24 default $(cc-version) if CC_IS_GCC 33 default $(cc-version) if CC_IS_GCC
25 default 0 34 default 0
26 35
27 config CC_IS_CLANG 36 config CC_IS_CLANG
28 def_bool $(success,test "$(cc-name)" = 37 def_bool $(success,test "$(cc-name)" = Clang)
29 38
30 config CLANG_VERSION 39 config CLANG_VERSION
31 int 40 int
32 default $(cc-version) if CC_IS_CLANG 41 default $(cc-version) if CC_IS_CLANG
33 default 0 42 default 0
34 43
35 config AS_IS_GNU <<
36 def_bool $(success,test "$(as-name)" = <<
37 <<
38 config AS_IS_LLVM <<
39 def_bool $(success,test "$(as-name)" = <<
40 <<
41 config AS_VERSION <<
42 int <<
43 # Use clang version if this is the int <<
44 default CLANG_VERSION if AS_IS_LLVM <<
45 default $(as-version) <<
46 <<
47 config LD_IS_BFD 44 config LD_IS_BFD
48 def_bool $(success,test "$(ld-name)" = 45 def_bool $(success,test "$(ld-name)" = BFD)
49 46
50 config LD_VERSION 47 config LD_VERSION
51 int 48 int
52 default $(ld-version) if LD_IS_BFD 49 default $(ld-version) if LD_IS_BFD
53 default 0 50 default 0
54 51
55 config LD_IS_LLD 52 config LD_IS_LLD
56 def_bool $(success,test "$(ld-name)" = 53 def_bool $(success,test "$(ld-name)" = LLD)
57 54
58 config LLD_VERSION 55 config LLD_VERSION
59 int 56 int
60 default $(ld-version) if LD_IS_LLD 57 default $(ld-version) if LD_IS_LLD
61 default 0 58 default 0
62 59
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 60 config CC_CAN_LINK
86 bool 61 bool
87 default $(success,$(srctree)/scripts/c !! 62 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m64-flag)) if 64BIT
88 default $(success,$(srctree)/scripts/c !! 63 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m32-flag))
89 64
90 config CC_CAN_LINK_STATIC 65 config CC_CAN_LINK_STATIC
91 bool 66 bool
92 default $(success,$(srctree)/scripts/c !! 67 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m64-flag) -static) if 64BIT
93 default $(success,$(srctree)/scripts/c !! 68 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m32-flag) -static)
94 69
95 # Fixed in GCC 14, 13.3, 12.4 and 11.5 !! 70 config CC_HAS_ASM_GOTO
96 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id !! 71 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 72
104 config CC_HAS_ASM_GOTO_OUTPUT 73 config CC_HAS_ASM_GOTO_OUTPUT
105 def_bool y !! 74 depends on CC_HAS_ASM_GOTO
106 depends on !GCC_ASM_GOTO_OUTPUT_BROKEN !! 75 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 76
114 config TOOLS_SUPPORT_RELR 77 config TOOLS_SUPPORT_RELR
115 def_bool $(success,env "CC=$(CC)" "LD= 78 def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh)
116 79
117 config CC_HAS_ASM_INLINE 80 config CC_HAS_ASM_INLINE
118 def_bool $(success,echo 'void foo(void 81 def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null)
119 82
120 config CC_HAS_NO_PROFILE_FN_ATTR <<
121 def_bool $(success,echo '__attribute__ <<
122 <<
123 config PAHOLE_VERSION <<
124 int <<
125 default $(shell,$(srctree)/scripts/pah <<
126 <<
127 config CONSTRUCTORS 83 config CONSTRUCTORS
128 bool 84 bool
129 85
130 config IRQ_WORK 86 config IRQ_WORK
131 def_bool y if SMP !! 87 bool
132 88
133 config BUILDTIME_TABLE_SORT 89 config BUILDTIME_TABLE_SORT
134 bool 90 bool
135 91
136 config THREAD_INFO_IN_TASK 92 config THREAD_INFO_IN_TASK
137 bool 93 bool
138 help 94 help
139 Select this to move thread_info off 95 Select this to move thread_info off the stack into task_struct. To
140 make this work, an arch will need to 96 make this work, an arch will need to remove all thread_info fields
141 except flags and fix any runtime bug 97 except flags and fix any runtime bugs.
142 98
143 One subtle change that will be neede 99 One subtle change that will be needed is to use try_get_task_stack()
144 and put_task_stack() in save_thread_ 100 and put_task_stack() in save_thread_stack_tsk() and get_wchan().
145 101
146 menu "General setup" 102 menu "General setup"
147 103
148 config BROKEN 104 config BROKEN
149 bool 105 bool
150 106
151 config BROKEN_ON_SMP 107 config BROKEN_ON_SMP
152 bool 108 bool
153 depends on BROKEN || !SMP 109 depends on BROKEN || !SMP
154 default y 110 default y
155 111
156 config INIT_ENV_ARG_LIMIT 112 config INIT_ENV_ARG_LIMIT
157 int 113 int
158 default 32 if !UML 114 default 32 if !UML
159 default 128 if UML 115 default 128 if UML
160 help 116 help
161 Maximum of each of the number of arg 117 Maximum of each of the number of arguments and environment
162 variables passed to init from the ke 118 variables passed to init from the kernel command line.
163 119
164 config COMPILE_TEST 120 config COMPILE_TEST
165 bool "Compile also drivers which will 121 bool "Compile also drivers which will not load"
166 depends on HAS_IOMEM 122 depends on HAS_IOMEM
167 help 123 help
168 Some drivers can be compiled on a di 124 Some drivers can be compiled on a different platform than they are
169 intended to be run on. Despite they 125 intended to be run on. Despite they cannot be loaded there (or even
170 when they load they cannot be used d 126 when they load they cannot be used due to missing HW support),
171 developers still, opposing to distri 127 developers still, opposing to distributors, might want to build such
172 drivers to compile-test them. 128 drivers to compile-test them.
173 129
174 If you are a developer and want to b 130 If you are a developer and want to build everything available, say Y
175 here. If you are a user/distributor, 131 here. If you are a user/distributor, say N here to exclude useless
176 drivers to be distributed. 132 drivers to be distributed.
177 133
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 134 config UAPI_HEADER_TEST
196 bool "Compile test UAPI headers" 135 bool "Compile test UAPI headers"
197 depends on HEADERS_INSTALL && CC_CAN_L 136 depends on HEADERS_INSTALL && CC_CAN_LINK
198 help 137 help
199 Compile test headers exported to use 138 Compile test headers exported to user-space to ensure they are
200 self-contained, i.e. compilable as s 139 self-contained, i.e. compilable as standalone units.
201 140
202 If you are a developer or tester and 141 If you are a developer or tester and want to ensure the exported
203 headers are self-contained, say Y he 142 headers are self-contained, say Y here. Otherwise, choose N.
204 143
205 config LOCALVERSION 144 config LOCALVERSION
206 string "Local version - append to kern 145 string "Local version - append to kernel release"
207 help 146 help
208 Append an extra string to the end of 147 Append an extra string to the end of your kernel version.
209 This will show up when you type unam 148 This will show up when you type uname, for example.
210 The string you set here will be appe 149 The string you set here will be appended after the contents of
211 any files with a filename matching l 150 any files with a filename matching localversion* in your
212 object and source tree, in that orde 151 object and source tree, in that order. Your total string can
213 be a maximum of 64 characters. 152 be a maximum of 64 characters.
214 153
215 config LOCALVERSION_AUTO 154 config LOCALVERSION_AUTO
216 bool "Automatically append version inf 155 bool "Automatically append version information to the version string"
217 default y 156 default y
218 depends on !COMPILE_TEST 157 depends on !COMPILE_TEST
219 help 158 help
220 This will try to automatically deter 159 This will try to automatically determine if the current tree is a
221 release tree by looking for git tags 160 release tree by looking for git tags that belong to the current
222 top of tree revision. 161 top of tree revision.
223 162
224 A string of the format -gxxxxxxxx wi 163 A string of the format -gxxxxxxxx will be added to the localversion
225 if a git-based tree is found. The s 164 if a git-based tree is found. The string generated by this will be
226 appended after any matching localver 165 appended after any matching localversion* files, and after the value
227 set in CONFIG_LOCALVERSION. 166 set in CONFIG_LOCALVERSION.
228 167
229 (The actual string used here is the !! 168 (The actual string used here is the first eight characters produced
230 by running the command: 169 by running the command:
231 170
232 $ git rev-parse --verify HEAD 171 $ git rev-parse --verify HEAD
233 172
234 which is done within the script "scr 173 which is done within the script "scripts/setlocalversion".)
235 174
236 config BUILD_SALT 175 config BUILD_SALT
237 string "Build ID Salt" 176 string "Build ID Salt"
238 default "" 177 default ""
239 help 178 help
240 The build ID is used to link binarie 179 The build ID is used to link binaries and their debug info. Setting
241 this option will use the value in th 180 this option will use the value in the calculation of the build id.
242 This is mostly useful for distributi 181 This is mostly useful for distributions which want to ensure the
243 build is unique between builds. It's 182 build is unique between builds. It's safe to leave the default.
244 183
245 config HAVE_KERNEL_GZIP 184 config HAVE_KERNEL_GZIP
246 bool 185 bool
247 186
248 config HAVE_KERNEL_BZIP2 187 config HAVE_KERNEL_BZIP2
249 bool 188 bool
250 189
251 config HAVE_KERNEL_LZMA 190 config HAVE_KERNEL_LZMA
252 bool 191 bool
253 192
254 config HAVE_KERNEL_XZ 193 config HAVE_KERNEL_XZ
255 bool 194 bool
256 195
257 config HAVE_KERNEL_LZO 196 config HAVE_KERNEL_LZO
258 bool 197 bool
259 198
260 config HAVE_KERNEL_LZ4 199 config HAVE_KERNEL_LZ4
261 bool 200 bool
262 201
263 config HAVE_KERNEL_ZSTD 202 config HAVE_KERNEL_ZSTD
264 bool 203 bool
265 204
266 config HAVE_KERNEL_UNCOMPRESSED 205 config HAVE_KERNEL_UNCOMPRESSED
267 bool 206 bool
268 207
269 choice 208 choice
270 prompt "Kernel compression mode" 209 prompt "Kernel compression mode"
271 default KERNEL_GZIP 210 default KERNEL_GZIP
272 depends on HAVE_KERNEL_GZIP || HAVE_KE 211 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 212 help
274 The linux kernel is a kind of self-e 213 The linux kernel is a kind of self-extracting executable.
275 Several compression algorithms are a 214 Several compression algorithms are available, which differ
276 in efficiency, compression and decom 215 in efficiency, compression and decompression speed.
277 Compression speed is only relevant w 216 Compression speed is only relevant when building a kernel.
278 Decompression speed is relevant at e 217 Decompression speed is relevant at each boot.
279 218
280 If you have any problems with bzip2 219 If you have any problems with bzip2 or lzma compressed
281 kernels, mail me (Alain Knaff) <alain 220 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
282 version of this functionality (bzip2 221 version of this functionality (bzip2 only), for 2.4, was
283 supplied by Christian Ludwig) 222 supplied by Christian Ludwig)
284 223
285 High compression options are mostly 224 High compression options are mostly useful for users, who
286 are low on disk space (embedded syst 225 are low on disk space (embedded systems), but for whom ram
287 size matters less. 226 size matters less.
288 227
289 If in doubt, select 'gzip' 228 If in doubt, select 'gzip'
290 229
291 config KERNEL_GZIP 230 config KERNEL_GZIP
292 bool "Gzip" 231 bool "Gzip"
293 depends on HAVE_KERNEL_GZIP 232 depends on HAVE_KERNEL_GZIP
294 help 233 help
295 The old and tried gzip compression. 234 The old and tried gzip compression. It provides a good balance
296 between compression ratio and decomp 235 between compression ratio and decompression speed.
297 236
298 config KERNEL_BZIP2 237 config KERNEL_BZIP2
299 bool "Bzip2" 238 bool "Bzip2"
300 depends on HAVE_KERNEL_BZIP2 239 depends on HAVE_KERNEL_BZIP2
301 help 240 help
302 Its compression ratio and speed is i 241 Its compression ratio and speed is intermediate.
303 Decompression speed is slowest among 242 Decompression speed is slowest among the choices. The kernel
304 size is about 10% smaller with bzip2 243 size is about 10% smaller with bzip2, in comparison to gzip.
305 Bzip2 uses a large amount of memory. 244 Bzip2 uses a large amount of memory. For modern kernels you
306 will need at least 8MB RAM or more f 245 will need at least 8MB RAM or more for booting.
307 246
308 config KERNEL_LZMA 247 config KERNEL_LZMA
309 bool "LZMA" 248 bool "LZMA"
310 depends on HAVE_KERNEL_LZMA 249 depends on HAVE_KERNEL_LZMA
311 help 250 help
312 This compression algorithm's ratio i 251 This compression algorithm's ratio is best. Decompression speed
313 is between gzip and bzip2. Compress 252 is between gzip and bzip2. Compression is slowest.
314 The kernel size is about 33% smaller 253 The kernel size is about 33% smaller with LZMA in comparison to gzip.
315 254
316 config KERNEL_XZ 255 config KERNEL_XZ
317 bool "XZ" 256 bool "XZ"
318 depends on HAVE_KERNEL_XZ 257 depends on HAVE_KERNEL_XZ
319 help 258 help
320 XZ uses the LZMA2 algorithm and inst 259 XZ uses the LZMA2 algorithm and instruction set specific
321 BCJ filters which can improve compre 260 BCJ filters which can improve compression ratio of executable
322 code. The size of the kernel is abou 261 code. The size of the kernel is about 30% smaller with XZ in
323 comparison to gzip. On architectures 262 comparison to gzip. On architectures for which there is a BCJ
324 filter (i386, x86_64, ARM, ARM64, RI !! 263 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
325 and SPARC), XZ will create a few per !! 264 will create a few percent smaller kernel than plain LZMA.
326 plain LZMA. <<
327 265
328 The speed is about the same as with 266 The speed is about the same as with LZMA: The decompression
329 speed of XZ is better than that of b 267 speed of XZ is better than that of bzip2 but worse than gzip
330 and LZO. Compression is slow. 268 and LZO. Compression is slow.
331 269
332 config KERNEL_LZO 270 config KERNEL_LZO
333 bool "LZO" 271 bool "LZO"
334 depends on HAVE_KERNEL_LZO 272 depends on HAVE_KERNEL_LZO
335 help 273 help
336 Its compression ratio is the poorest 274 Its compression ratio is the poorest among the choices. The kernel
337 size is about 10% bigger than gzip; 275 size is about 10% bigger than gzip; however its speed
338 (both compression and decompression) 276 (both compression and decompression) is the fastest.
339 277
340 config KERNEL_LZ4 278 config KERNEL_LZ4
341 bool "LZ4" 279 bool "LZ4"
342 depends on HAVE_KERNEL_LZ4 280 depends on HAVE_KERNEL_LZ4
343 help 281 help
344 LZ4 is an LZ77-type compressor with 282 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
345 A preliminary version of LZ4 de/comp 283 A preliminary version of LZ4 de/compression tool is available at
346 <https://code.google.com/p/lz4/>. 284 <https://code.google.com/p/lz4/>.
347 285
348 Its compression ratio is worse than 286 Its compression ratio is worse than LZO. The size of the kernel
349 is about 8% bigger than LZO. But the 287 is about 8% bigger than LZO. But the decompression speed is
350 faster than LZO. 288 faster than LZO.
351 289
352 config KERNEL_ZSTD 290 config KERNEL_ZSTD
353 bool "ZSTD" 291 bool "ZSTD"
354 depends on HAVE_KERNEL_ZSTD 292 depends on HAVE_KERNEL_ZSTD
355 help 293 help
356 ZSTD is a compression algorithm targ 294 ZSTD is a compression algorithm targeting intermediate compression
357 with fast decompression speed. It wi 295 with fast decompression speed. It will compress better than GZIP and
358 decompress around the same speed as 296 decompress around the same speed as LZO, but slower than LZ4. You
359 will need at least 192 KB RAM or mor 297 will need at least 192 KB RAM or more for booting. The zstd command
360 line tool is required for compressio 298 line tool is required for compression.
361 299
362 config KERNEL_UNCOMPRESSED 300 config KERNEL_UNCOMPRESSED
363 bool "None" 301 bool "None"
364 depends on HAVE_KERNEL_UNCOMPRESSED 302 depends on HAVE_KERNEL_UNCOMPRESSED
365 help 303 help
366 Produce uncompressed kernel image. T 304 Produce uncompressed kernel image. This option is usually not what
367 you want. It is useful for debugging 305 you want. It is useful for debugging the kernel in slow simulation
368 environments, where decompressing an 306 environments, where decompressing and moving the kernel is awfully
369 slow. This option allows early boot 307 slow. This option allows early boot code to skip the decompressor
370 and jump right at uncompressed kerne 308 and jump right at uncompressed kernel image.
371 309
372 endchoice 310 endchoice
373 311
374 config DEFAULT_INIT 312 config DEFAULT_INIT
375 string "Default init path" 313 string "Default init path"
376 default "" 314 default ""
377 help 315 help
378 This option determines the default i 316 This option determines the default init for the system if no init=
379 option is passed on the kernel comma 317 option is passed on the kernel command line. If the requested path is
380 not present, we will still then move 318 not present, we will still then move on to attempting further
381 locations (e.g. /sbin/init, etc). If 319 locations (e.g. /sbin/init, etc). If this is empty, we will just use
382 the fallback list when init= is not 320 the fallback list when init= is not passed.
383 321
384 config DEFAULT_HOSTNAME 322 config DEFAULT_HOSTNAME
385 string "Default hostname" 323 string "Default hostname"
386 default "(none)" 324 default "(none)"
387 help 325 help
388 This option determines the default s 326 This option determines the default system hostname before userspace
389 calls sethostname(2). The kernel tra 327 calls sethostname(2). The kernel traditionally uses "(none)" here,
390 but you may wish to use a different 328 but you may wish to use a different default here to make a minimal
391 system more usable with less configu 329 system more usable with less configuration.
392 330
>> 331 #
>> 332 # For some reason microblaze and nios2 hard code SWAP=n. Hopefully we can
>> 333 # add proper SWAP support to them, in which case this can be remove.
>> 334 #
>> 335 config ARCH_NO_SWAP
>> 336 bool
>> 337
>> 338 config SWAP
>> 339 bool "Support for paging of anonymous memory (swap)"
>> 340 depends on MMU && BLOCK && !ARCH_NO_SWAP
>> 341 default y
>> 342 help
>> 343 This option allows you to choose whether you want to have support
>> 344 for so called swap devices or swap files in your kernel that are
>> 345 used to provide more virtual memory than the actual RAM present
>> 346 in your computer. If unsure say Y.
>> 347
393 config SYSVIPC 348 config SYSVIPC
394 bool "System V IPC" 349 bool "System V IPC"
395 help 350 help
396 Inter Process Communication is a sui 351 Inter Process Communication is a suite of library functions and
397 system calls which let processes (ru 352 system calls which let processes (running programs) synchronize and
398 exchange information. It is generall 353 exchange information. It is generally considered to be a good thing,
399 and some programs won't run unless y 354 and some programs won't run unless you say Y here. In particular, if
400 you want to run the DOS emulator dos 355 you want to run the DOS emulator dosemu under Linux (read the
401 DOSEMU-HOWTO, available from <http:/ 356 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
402 you'll need to say Y here. 357 you'll need to say Y here.
403 358
404 You can find documentation about IPC 359 You can find documentation about IPC with "info ipc" and also in
405 section 6.4 of the Linux Programmer' 360 section 6.4 of the Linux Programmer's Guide, available from
406 <http://www.tldp.org/guides.html>. 361 <http://www.tldp.org/guides.html>.
407 362
408 config SYSVIPC_SYSCTL 363 config SYSVIPC_SYSCTL
409 bool 364 bool
410 depends on SYSVIPC 365 depends on SYSVIPC
411 depends on SYSCTL 366 depends on SYSCTL
412 default y 367 default y
413 368
414 config SYSVIPC_COMPAT <<
415 def_bool y <<
416 depends on COMPAT && SYSVIPC <<
417 <<
418 config POSIX_MQUEUE 369 config POSIX_MQUEUE
419 bool "POSIX Message Queues" 370 bool "POSIX Message Queues"
420 depends on NET 371 depends on NET
421 help 372 help
422 POSIX variant of message queues is a 373 POSIX variant of message queues is a part of IPC. In POSIX message
423 queues every message has a priority 374 queues every message has a priority which decides about succession
424 of receiving it by a process. If you 375 of receiving it by a process. If you want to compile and run
425 programs written e.g. for Solaris wi 376 programs written e.g. for Solaris with use of its POSIX message
426 queues (functions mq_*) say Y here. 377 queues (functions mq_*) say Y here.
427 378
428 POSIX message queues are visible as 379 POSIX message queues are visible as a filesystem called 'mqueue'
429 and can be mounted somewhere if you 380 and can be mounted somewhere if you want to do filesystem
430 operations on message queues. 381 operations on message queues.
431 382
432 If unsure, say Y. 383 If unsure, say Y.
433 384
434 config POSIX_MQUEUE_SYSCTL 385 config POSIX_MQUEUE_SYSCTL
435 bool 386 bool
436 depends on POSIX_MQUEUE 387 depends on POSIX_MQUEUE
437 depends on SYSCTL 388 depends on SYSCTL
438 default y 389 default y
439 390
440 config WATCH_QUEUE 391 config WATCH_QUEUE
441 bool "General notification queue" 392 bool "General notification queue"
442 default n 393 default n
443 help 394 help
444 395
445 This is a general notification queue 396 This is a general notification queue for the kernel to pass events to
446 userspace by splicing them into pipe 397 userspace by splicing them into pipes. It can be used in conjunction
447 with watches for key/keyring change 398 with watches for key/keyring change notifications and device
448 notifications. 399 notifications.
449 400
450 See Documentation/core-api/watch_que !! 401 See Documentation/watch_queue.rst
451 402
452 config CROSS_MEMORY_ATTACH 403 config CROSS_MEMORY_ATTACH
453 bool "Enable process_vm_readv/writev s 404 bool "Enable process_vm_readv/writev syscalls"
454 depends on MMU 405 depends on MMU
455 default y 406 default y
456 help 407 help
457 Enabling this option adds the system 408 Enabling this option adds the system calls process_vm_readv and
458 process_vm_writev which allow a proc 409 process_vm_writev which allow a process with the correct privileges
459 to directly read from or write to an 410 to directly read from or write to another process' address space.
460 See the man page for more details. 411 See the man page for more details.
461 412
462 config USELIB 413 config USELIB
463 bool "uselib syscall (for libc5 and ea !! 414 bool "uselib syscall"
464 default ALPHA || M68K || SPARC !! 415 def_bool ALPHA || M68K || SPARC || X86_32 || IA32_EMULATION
465 help 416 help
466 This option enables the uselib sysca 417 This option enables the uselib syscall, a system call used in the
467 dynamic linker from libc5 and earlie 418 dynamic linker from libc5 and earlier. glibc does not use this
468 system call. If you intend to run p 419 system call. If you intend to run programs built on libc5 or
469 earlier, you may need to enable this 420 earlier, you may need to enable this syscall. Current systems
470 running glibc can safely disable thi 421 running glibc can safely disable this.
471 422
472 config AUDIT 423 config AUDIT
473 bool "Auditing support" 424 bool "Auditing support"
474 depends on NET 425 depends on NET
475 help 426 help
476 Enable auditing infrastructure that 427 Enable auditing infrastructure that can be used with another
477 kernel subsystem, such as SELinux (w 428 kernel subsystem, such as SELinux (which requires this for
478 logging of avc messages output). Sy 429 logging of avc messages output). System call auditing is included
479 on architectures which support it. 430 on architectures which support it.
480 431
481 config HAVE_ARCH_AUDITSYSCALL 432 config HAVE_ARCH_AUDITSYSCALL
482 bool 433 bool
483 434
484 config AUDITSYSCALL 435 config AUDITSYSCALL
485 def_bool y 436 def_bool y
486 depends on AUDIT && HAVE_ARCH_AUDITSYS 437 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
487 select FSNOTIFY 438 select FSNOTIFY
488 439
489 source "kernel/irq/Kconfig" 440 source "kernel/irq/Kconfig"
490 source "kernel/time/Kconfig" 441 source "kernel/time/Kconfig"
491 source "kernel/bpf/Kconfig" <<
492 source "kernel/Kconfig.preempt" 442 source "kernel/Kconfig.preempt"
493 443
494 menu "CPU/Task time and stats accounting" 444 menu "CPU/Task time and stats accounting"
495 445
496 config VIRT_CPU_ACCOUNTING 446 config VIRT_CPU_ACCOUNTING
497 bool 447 bool
498 448
499 choice 449 choice
500 prompt "Cputime accounting" 450 prompt "Cputime accounting"
501 default TICK_CPU_ACCOUNTING !! 451 default TICK_CPU_ACCOUNTING if !PPC64
>> 452 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
502 453
503 # Kind of a stub config for the pure tick base 454 # Kind of a stub config for the pure tick based cputime accounting
504 config TICK_CPU_ACCOUNTING 455 config TICK_CPU_ACCOUNTING
505 bool "Simple tick based cputime accoun 456 bool "Simple tick based cputime accounting"
506 depends on !S390 && !NO_HZ_FULL 457 depends on !S390 && !NO_HZ_FULL
507 help 458 help
508 This is the basic tick based cputime 459 This is the basic tick based cputime accounting that maintains
509 statistics about user, system and id 460 statistics about user, system and idle time spent on per jiffies
510 granularity. 461 granularity.
511 462
512 If unsure, say Y. 463 If unsure, say Y.
513 464
514 config VIRT_CPU_ACCOUNTING_NATIVE 465 config VIRT_CPU_ACCOUNTING_NATIVE
515 bool "Deterministic task and CPU time 466 bool "Deterministic task and CPU time accounting"
516 depends on HAVE_VIRT_CPU_ACCOUNTING && 467 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
517 select VIRT_CPU_ACCOUNTING 468 select VIRT_CPU_ACCOUNTING
518 help 469 help
519 Select this option to enable more ac 470 Select this option to enable more accurate task and CPU time
520 accounting. This is done by reading 471 accounting. This is done by reading a CPU counter on each
521 kernel entry and exit and on transit 472 kernel entry and exit and on transitions within the kernel
522 between system, softirq and hardirq 473 between system, softirq and hardirq state, so there is a
523 small performance impact. In the ca 474 small performance impact. In the case of s390 or IBM POWER > 5,
524 this also enables accounting of stol 475 this also enables accounting of stolen time on logically-partitioned
525 systems. 476 systems.
526 477
527 config VIRT_CPU_ACCOUNTING_GEN 478 config VIRT_CPU_ACCOUNTING_GEN
528 bool "Full dynticks CPU time accountin 479 bool "Full dynticks CPU time accounting"
529 depends on HAVE_CONTEXT_TRACKING_USER !! 480 depends on HAVE_CONTEXT_TRACKING
530 depends on HAVE_VIRT_CPU_ACCOUNTING_GE 481 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
531 depends on GENERIC_CLOCKEVENTS 482 depends on GENERIC_CLOCKEVENTS
532 select VIRT_CPU_ACCOUNTING 483 select VIRT_CPU_ACCOUNTING
533 select CONTEXT_TRACKING_USER !! 484 select CONTEXT_TRACKING
534 help 485 help
535 Select this option to enable task an 486 Select this option to enable task and CPU time accounting on full
536 dynticks systems. This accounting is 487 dynticks systems. This accounting is implemented by watching every
537 kernel-user boundaries using the con 488 kernel-user boundaries using the context tracking subsystem.
538 The accounting is thus performed at 489 The accounting is thus performed at the expense of some significant
539 overhead. 490 overhead.
540 491
541 For now this is only useful if you a 492 For now this is only useful if you are working on the full
542 dynticks subsystem development. 493 dynticks subsystem development.
543 494
544 If unsure, say N. 495 If unsure, say N.
545 496
546 endchoice 497 endchoice
547 498
548 config IRQ_TIME_ACCOUNTING 499 config IRQ_TIME_ACCOUNTING
549 bool "Fine granularity task level IRQ 500 bool "Fine granularity task level IRQ time accounting"
550 depends on HAVE_IRQ_TIME_ACCOUNTING && 501 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
551 help 502 help
552 Select this option to enable fine gr 503 Select this option to enable fine granularity task irq time
553 accounting. This is done by reading 504 accounting. This is done by reading a timestamp on each
554 transitions between softirq and hard 505 transitions between softirq and hardirq state, so there can be a
555 small performance impact. 506 small performance impact.
556 507
557 If in doubt, say N here. 508 If in doubt, say N here.
558 509
559 config HAVE_SCHED_AVG_IRQ 510 config HAVE_SCHED_AVG_IRQ
560 def_bool y 511 def_bool y
561 depends on IRQ_TIME_ACCOUNTING || PARA 512 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING
562 depends on SMP 513 depends on SMP
563 514
564 config SCHED_HW_PRESSURE !! 515 config SCHED_THERMAL_PRESSURE
565 bool 516 bool
566 default y if ARM && ARM_CPU_TOPOLOGY 517 default y if ARM && ARM_CPU_TOPOLOGY
567 default y if ARM64 518 default y if ARM64
568 depends on SMP 519 depends on SMP
569 depends on CPU_FREQ_THERMAL 520 depends on CPU_FREQ_THERMAL
570 help 521 help
571 Select this option to enable HW pres !! 522 Select this option to enable thermal pressure accounting in the
572 scheduler. HW pressure is the value !! 523 scheduler. Thermal pressure is the value conveyed to the scheduler
573 that reflects the reduction in CPU c 524 that reflects the reduction in CPU compute capacity resulted from
574 HW throttling. HW throttling occurs !! 525 thermal throttling. Thermal throttling occurs when the performance of
575 a CPU is capped due to high operatin !! 526 a CPU is capped due to high operating temperatures.
576 527
577 If selected, the scheduler will be a 528 If selected, the scheduler will be able to balance tasks accordingly,
578 i.e. put less load on throttled CPUs 529 i.e. put less load on throttled CPUs than on non/less throttled ones.
579 530
580 This requires the architecture to im 531 This requires the architecture to implement
581 arch_update_hw_pressure() and arch_s !! 532 arch_set_thermal_pressure() and arch_scale_thermal_pressure().
582 533
583 config BSD_PROCESS_ACCT 534 config BSD_PROCESS_ACCT
584 bool "BSD Process Accounting" 535 bool "BSD Process Accounting"
585 depends on MULTIUSER 536 depends on MULTIUSER
586 help 537 help
587 If you say Y here, a user level prog 538 If you say Y here, a user level program will be able to instruct the
588 kernel (via a special system call) t 539 kernel (via a special system call) to write process accounting
589 information to a file: whenever a pr 540 information to a file: whenever a process exits, information about
590 that process will be appended to the 541 that process will be appended to the file by the kernel. The
591 information includes things such as 542 information includes things such as creation time, owning user,
592 command name, memory usage, controll 543 command name, memory usage, controlling terminal etc. (the complete
593 list is in the struct acct in <file: 544 list is in the struct acct in <file:include/linux/acct.h>). It is
594 up to the user level program to do u 545 up to the user level program to do useful things with this
595 information. This is generally a go 546 information. This is generally a good idea, so say Y.
596 547
597 config BSD_PROCESS_ACCT_V3 548 config BSD_PROCESS_ACCT_V3
598 bool "BSD Process Accounting version 3 549 bool "BSD Process Accounting version 3 file format"
599 depends on BSD_PROCESS_ACCT 550 depends on BSD_PROCESS_ACCT
600 default n 551 default n
601 help 552 help
602 If you say Y here, the process accou 553 If you say Y here, the process accounting information is written
603 in a new file format that also logs 554 in a new file format that also logs the process IDs of each
604 process and its parent. Note that th 555 process and its parent. Note that this file format is incompatible
605 with previous v0/v1/v2 file formats, 556 with previous v0/v1/v2 file formats, so you will need updated tools
606 for processing it. A preliminary ver 557 for processing it. A preliminary version of these tools is available
607 at <http://www.gnu.org/software/acct 558 at <http://www.gnu.org/software/acct/>.
608 559
609 config TASKSTATS 560 config TASKSTATS
610 bool "Export task/process statistics t 561 bool "Export task/process statistics through netlink"
611 depends on NET 562 depends on NET
612 depends on MULTIUSER 563 depends on MULTIUSER
613 default n 564 default n
614 help 565 help
615 Export selected statistics for tasks 566 Export selected statistics for tasks/processes through the
616 generic netlink interface. Unlike BS 567 generic netlink interface. Unlike BSD process accounting, the
617 statistics are available during the 568 statistics are available during the lifetime of tasks/processes as
618 responses to commands. Like BSD acco 569 responses to commands. Like BSD accounting, they are sent to user
619 space on task exit. 570 space on task exit.
620 571
621 Say N if unsure. 572 Say N if unsure.
622 573
623 config TASK_DELAY_ACCT 574 config TASK_DELAY_ACCT
624 bool "Enable per-task delay accounting 575 bool "Enable per-task delay accounting"
625 depends on TASKSTATS 576 depends on TASKSTATS
626 select SCHED_INFO 577 select SCHED_INFO
627 help 578 help
628 Collect information on time spent by 579 Collect information on time spent by a task waiting for system
629 resources like cpu, synchronous bloc 580 resources like cpu, synchronous block I/O completion and swapping
630 in pages. Such statistics can help i 581 in pages. Such statistics can help in setting a task's priorities
631 relative to other tasks for cpu, io, 582 relative to other tasks for cpu, io, rss limits etc.
632 583
633 Say N if unsure. 584 Say N if unsure.
634 585
635 config TASK_XACCT 586 config TASK_XACCT
636 bool "Enable extended accounting over 587 bool "Enable extended accounting over taskstats"
637 depends on TASKSTATS 588 depends on TASKSTATS
638 help 589 help
639 Collect extended task accounting dat 590 Collect extended task accounting data and send the data
640 to userland for processing over the 591 to userland for processing over the taskstats interface.
641 592
642 Say N if unsure. 593 Say N if unsure.
643 594
644 config TASK_IO_ACCOUNTING 595 config TASK_IO_ACCOUNTING
645 bool "Enable per-task storage I/O acco 596 bool "Enable per-task storage I/O accounting"
646 depends on TASK_XACCT 597 depends on TASK_XACCT
647 help 598 help
648 Collect information on the number of 599 Collect information on the number of bytes of storage I/O which this
649 task has caused. 600 task has caused.
650 601
651 Say N if unsure. 602 Say N if unsure.
652 603
653 config PSI 604 config PSI
654 bool "Pressure stall information track 605 bool "Pressure stall information tracking"
655 select KERNFS <<
656 help 606 help
657 Collect metrics that indicate how ov 607 Collect metrics that indicate how overcommitted the CPU, memory,
658 and IO capacity are in the system. 608 and IO capacity are in the system.
659 609
660 If you say Y here, the kernel will c 610 If you say Y here, the kernel will create /proc/pressure/ with the
661 pressure statistics files cpu, memor 611 pressure statistics files cpu, memory, and io. These will indicate
662 the share of walltime in which some 612 the share of walltime in which some or all tasks in the system are
663 delayed due to contention of the res 613 delayed due to contention of the respective resource.
664 614
665 In kernels with cgroup support, cgro 615 In kernels with cgroup support, cgroups (cgroup2 only) will
666 have cpu.pressure, memory.pressure, 616 have cpu.pressure, memory.pressure, and io.pressure files,
667 which aggregate pressure stalls for 617 which aggregate pressure stalls for the grouped tasks only.
668 618
669 For more details see Documentation/a 619 For more details see Documentation/accounting/psi.rst.
670 620
671 Say N if unsure. 621 Say N if unsure.
672 622
673 config PSI_DEFAULT_DISABLED 623 config PSI_DEFAULT_DISABLED
674 bool "Require boot parameter to enable 624 bool "Require boot parameter to enable pressure stall information tracking"
675 default n 625 default n
676 depends on PSI 626 depends on PSI
677 help 627 help
678 If set, pressure stall information t 628 If set, pressure stall information tracking will be disabled
679 per default but can be enabled throu 629 per default but can be enabled through passing psi=1 on the
680 kernel commandline during boot. 630 kernel commandline during boot.
681 631
682 This feature adds some code to the t 632 This feature adds some code to the task wakeup and sleep
683 paths of the scheduler. The overhead 633 paths of the scheduler. The overhead is too low to affect
684 common scheduling-intense workloads 634 common scheduling-intense workloads in practice (such as
685 webservers, memcache), but it does s 635 webservers, memcache), but it does show up in artificial
686 scheduler stress tests, such as hack 636 scheduler stress tests, such as hackbench.
687 637
688 If you are paranoid and not sure wha 638 If you are paranoid and not sure what the kernel will be
689 used for, say Y. 639 used for, say Y.
690 640
691 Say N if unsure. 641 Say N if unsure.
692 642
693 endmenu # "CPU/Task time and stats accounting" 643 endmenu # "CPU/Task time and stats accounting"
694 644
695 config CPU_ISOLATION 645 config CPU_ISOLATION
696 bool "CPU isolation" 646 bool "CPU isolation"
697 depends on SMP || COMPILE_TEST 647 depends on SMP || COMPILE_TEST
698 default y 648 default y
699 help 649 help
700 Make sure that CPUs running critical 650 Make sure that CPUs running critical tasks are not disturbed by
701 any source of "noise" such as unboun 651 any source of "noise" such as unbound workqueues, timers, kthreads...
702 Unbound jobs get offloaded to housek 652 Unbound jobs get offloaded to housekeeping CPUs. This is driven by
703 the "isolcpus=" boot parameter. 653 the "isolcpus=" boot parameter.
704 654
705 Say Y if unsure. 655 Say Y if unsure.
706 656
707 source "kernel/rcu/Kconfig" 657 source "kernel/rcu/Kconfig"
708 658
>> 659 config BUILD_BIN2C
>> 660 bool
>> 661 default n
>> 662
709 config IKCONFIG 663 config IKCONFIG
710 tristate "Kernel .config support" 664 tristate "Kernel .config support"
711 help 665 help
712 This option enables the complete Lin 666 This option enables the complete Linux kernel ".config" file
713 contents to be saved in the kernel. 667 contents to be saved in the kernel. It provides documentation
714 of which kernel options are used in 668 of which kernel options are used in a running kernel or in an
715 on-disk kernel. This information ca 669 on-disk kernel. This information can be extracted from the kernel
716 image file with the script scripts/e 670 image file with the script scripts/extract-ikconfig and used as
717 input to rebuild the current kernel 671 input to rebuild the current kernel or to build another kernel.
718 It can also be extracted from a runn 672 It can also be extracted from a running kernel by reading
719 /proc/config.gz if enabled (below). 673 /proc/config.gz if enabled (below).
720 674
721 config IKCONFIG_PROC 675 config IKCONFIG_PROC
722 bool "Enable access to .config through 676 bool "Enable access to .config through /proc/config.gz"
723 depends on IKCONFIG && PROC_FS 677 depends on IKCONFIG && PROC_FS
724 help 678 help
725 This option enables access to the ke 679 This option enables access to the kernel configuration file
726 through /proc/config.gz. 680 through /proc/config.gz.
727 681
728 config IKHEADERS 682 config IKHEADERS
729 tristate "Enable kernel headers throug 683 tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz"
730 depends on SYSFS 684 depends on SYSFS
731 help 685 help
732 This option enables access to the in 686 This option enables access to the in-kernel headers that are generated during
733 the build process. These can be used 687 the build process. These can be used to build eBPF tracing programs,
734 or similar programs. If you build t 688 or similar programs. If you build the headers as a module, a module called
735 kheaders.ko is built which can be lo 689 kheaders.ko is built which can be loaded on-demand to get access to headers.
736 690
737 config LOG_BUF_SHIFT 691 config LOG_BUF_SHIFT
738 int "Kernel log buffer size (16 => 64K 692 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
739 range 12 25 !! 693 range 12 25 if !H8300
>> 694 range 12 19 if H8300
740 default 17 695 default 17
741 depends on PRINTK 696 depends on PRINTK
742 help 697 help
743 Select the minimal kernel log buffer 698 Select the minimal kernel log buffer size as a power of 2.
744 The final size is affected by LOG_CP 699 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
745 parameter, see below. Any higher siz 700 parameter, see below. Any higher size also might be forced
746 by "log_buf_len" boot parameter. 701 by "log_buf_len" boot parameter.
747 702
748 Examples: 703 Examples:
749 17 => 128 KB 704 17 => 128 KB
750 16 => 64 KB 705 16 => 64 KB
751 15 => 32 KB 706 15 => 32 KB
752 14 => 16 KB 707 14 => 16 KB
753 13 => 8 KB 708 13 => 8 KB
754 12 => 4 KB 709 12 => 4 KB
755 710
756 config LOG_CPU_MAX_BUF_SHIFT 711 config LOG_CPU_MAX_BUF_SHIFT
757 int "CPU kernel log buffer size contri 712 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
758 depends on SMP 713 depends on SMP
759 range 0 21 714 range 0 21
>> 715 default 12 if !BASE_SMALL
760 default 0 if BASE_SMALL 716 default 0 if BASE_SMALL
761 default 12 <<
762 depends on PRINTK 717 depends on PRINTK
763 help 718 help
764 This option allows to increase the d 719 This option allows to increase the default ring buffer size
765 according to the number of CPUs. The 720 according to the number of CPUs. The value defines the contribution
766 of each CPU as a power of 2. The use 721 of each CPU as a power of 2. The used space is typically only few
767 lines however it might be much more 722 lines however it might be much more when problems are reported,
768 e.g. backtraces. 723 e.g. backtraces.
769 724
770 The increased size means that a new 725 The increased size means that a new buffer has to be allocated and
771 the original static one is unused. I 726 the original static one is unused. It makes sense only on systems
772 with more CPUs. Therefore this value 727 with more CPUs. Therefore this value is used only when the sum of
773 contributions is greater than the ha 728 contributions is greater than the half of the default kernel ring
774 buffer as defined by LOG_BUF_SHIFT. 729 buffer as defined by LOG_BUF_SHIFT. The default values are set
775 so that more than 16 CPUs are needed 730 so that more than 16 CPUs are needed to trigger the allocation.
776 731
777 Also this option is ignored when "lo 732 Also this option is ignored when "log_buf_len" kernel parameter is
778 used as it forces an exact (power of 733 used as it forces an exact (power of two) size of the ring buffer.
779 734
780 The number of possible CPUs is used 735 The number of possible CPUs is used for this computation ignoring
781 hotplugging making the computation o 736 hotplugging making the computation optimal for the worst case
782 scenario while allowing a simple alg 737 scenario while allowing a simple algorithm to be used from bootup.
783 738
784 Examples shift values and their mean 739 Examples shift values and their meaning:
785 17 => 128 KB for each CPU 740 17 => 128 KB for each CPU
786 16 => 64 KB for each CPU 741 16 => 64 KB for each CPU
787 15 => 32 KB for each CPU 742 15 => 32 KB for each CPU
788 14 => 16 KB for each CPU 743 14 => 16 KB for each CPU
789 13 => 8 KB for each CPU 744 13 => 8 KB for each CPU
790 12 => 4 KB for each CPU 745 12 => 4 KB for each CPU
791 746
792 config PRINTK_INDEX !! 747 config PRINTK_SAFE_LOG_BUF_SHIFT
793 bool "Printk indexing debugfs interfac !! 748 int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)"
794 depends on PRINTK && DEBUG_FS !! 749 range 10 21
795 help !! 750 default 13
796 Add support for indexing of all prin !! 751 depends on PRINTK
797 at <debugfs>/printk/index/<module>. !! 752 help
798 !! 753 Select the size of an alternate printk per-CPU buffer where messages
799 This can be used as part of maintain !! 754 printed from usafe contexts are temporary stored. One example would
800 /dev/kmsg, as it permits auditing th !! 755 be NMI messages, another one - printk recursion. The messages are
801 kernel, allowing detection of cases !! 756 copied to the main log buffer in a safe context to avoid a deadlock.
802 changed or no longer present. !! 757 The value defines the size as a power of 2.
>> 758
>> 759 Those messages are rare and limited. The largest one is when
>> 760 a backtrace is printed. It usually fits into 4KB. Select
>> 761 8KB if you want to be on the safe side.
803 762
804 There is no additional runtime cost !! 763 Examples:
>> 764 17 => 128 KB for each CPU
>> 765 16 => 64 KB for each CPU
>> 766 15 => 32 KB for each CPU
>> 767 14 => 16 KB for each CPU
>> 768 13 => 8 KB for each CPU
>> 769 12 => 4 KB for each CPU
805 770
806 # 771 #
807 # Architectures with an unreliable sched_clock 772 # Architectures with an unreliable sched_clock() should select this:
808 # 773 #
809 config HAVE_UNSTABLE_SCHED_CLOCK 774 config HAVE_UNSTABLE_SCHED_CLOCK
810 bool 775 bool
811 776
812 config GENERIC_SCHED_CLOCK 777 config GENERIC_SCHED_CLOCK
813 bool 778 bool
814 779
815 menu "Scheduler features" 780 menu "Scheduler features"
816 781
817 config UCLAMP_TASK 782 config UCLAMP_TASK
818 bool "Enable utilization clamping for 783 bool "Enable utilization clamping for RT/FAIR tasks"
819 depends on CPU_FREQ_GOV_SCHEDUTIL 784 depends on CPU_FREQ_GOV_SCHEDUTIL
820 help 785 help
821 This feature enables the scheduler t 786 This feature enables the scheduler to track the clamped utilization
822 of each CPU based on RUNNABLE tasks 787 of each CPU based on RUNNABLE tasks scheduled on that CPU.
823 788
824 With this option, the user can speci 789 With this option, the user can specify the min and max CPU
825 utilization allowed for RUNNABLE tas 790 utilization allowed for RUNNABLE tasks. The max utilization defines
826 the maximum frequency a task should 791 the maximum frequency a task should use while the min utilization
827 defines the minimum frequency it sho 792 defines the minimum frequency it should use.
828 793
829 Both min and max utilization clamp v 794 Both min and max utilization clamp values are hints to the scheduler,
830 aiming at improving its frequency se 795 aiming at improving its frequency selection policy, but they do not
831 enforce or grant any specific bandwi 796 enforce or grant any specific bandwidth for tasks.
832 797
833 If in doubt, say N. 798 If in doubt, say N.
834 799
835 config UCLAMP_BUCKETS_COUNT 800 config UCLAMP_BUCKETS_COUNT
836 int "Number of supported utilization c 801 int "Number of supported utilization clamp buckets"
837 range 5 20 802 range 5 20
838 default 5 803 default 5
839 depends on UCLAMP_TASK 804 depends on UCLAMP_TASK
840 help 805 help
841 Defines the number of clamp buckets 806 Defines the number of clamp buckets to use. The range of each bucket
842 will be SCHED_CAPACITY_SCALE/UCLAMP_ 807 will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the
843 number of clamp buckets the finer th 808 number of clamp buckets the finer their granularity and the higher
844 the precision of clamping aggregatio 809 the precision of clamping aggregation and tracking at run-time.
845 810
846 For example, with the minimum config 811 For example, with the minimum configuration value we will have 5
847 clamp buckets tracking 20% utilizati 812 clamp buckets tracking 20% utilization each. A 25% boosted tasks will
848 be refcounted in the [20..39]% bucke 813 be refcounted in the [20..39]% bucket and will set the bucket clamp
849 effective value to 25%. 814 effective value to 25%.
850 If a second 30% boosted task should 815 If a second 30% boosted task should be co-scheduled on the same CPU,
851 that task will be refcounted in the 816 that task will be refcounted in the same bucket of the first task and
852 it will boost the bucket clamp effec 817 it will boost the bucket clamp effective value to 30%.
853 The clamp effective value of a bucke 818 The clamp effective value of a bucket is reset to its nominal value
854 (20% in the example above) when ther 819 (20% in the example above) when there are no more tasks refcounted in
855 that bucket. 820 that bucket.
856 821
857 An additional boost/capping margin c 822 An additional boost/capping margin can be added to some tasks. In the
858 example above the 25% task will be b 823 example above the 25% task will be boosted to 30% until it exits the
859 CPU. If that should be considered no 824 CPU. If that should be considered not acceptable on certain systems,
860 it's always possible to reduce the m 825 it's always possible to reduce the margin by increasing the number of
861 clamp buckets to trade off used memo 826 clamp buckets to trade off used memory for run-time tracking
862 precision. 827 precision.
863 828
864 If in doubt, use the default value. 829 If in doubt, use the default value.
865 830
866 endmenu 831 endmenu
867 832
868 # 833 #
869 # For architectures that want to enable the su 834 # For architectures that want to enable the support for NUMA-affine scheduler
870 # balancing logic: 835 # balancing logic:
871 # 836 #
872 config ARCH_SUPPORTS_NUMA_BALANCING 837 config ARCH_SUPPORTS_NUMA_BALANCING
873 bool 838 bool
874 839
875 # 840 #
876 # For architectures that prefer to flush all T 841 # For architectures that prefer to flush all TLBs after a number of pages
877 # are unmapped instead of sending one IPI per 842 # are unmapped instead of sending one IPI per page to flush. The architecture
878 # must provide guarantees on what happens if a 843 # must provide guarantees on what happens if a clean TLB cache entry is
879 # written after the unmap. Details are in mm/r 844 # written after the unmap. Details are in mm/rmap.c near the check for
880 # should_defer_flush. The architecture should 845 # should_defer_flush. The architecture should also consider if the full flush
881 # and the refill costs are offset by the savin 846 # and the refill costs are offset by the savings of sending fewer IPIs.
882 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 847 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
883 bool 848 bool
884 849
885 config CC_HAS_INT128 850 config CC_HAS_INT128
886 def_bool !$(cc-option,$(m64-flag) -D__ 851 def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT
887 852
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 # 853 #
915 # For architectures that know their GCC __int1 854 # For architectures that know their GCC __int128 support is sound
916 # 855 #
917 config ARCH_SUPPORTS_INT128 856 config ARCH_SUPPORTS_INT128
918 bool 857 bool
919 858
920 # For architectures that (ab)use NUMA to repre 859 # For architectures that (ab)use NUMA to represent different memory regions
921 # all cpu-local but of different latencies, su 860 # all cpu-local but of different latencies, such as SuperH.
922 # 861 #
923 config ARCH_WANT_NUMA_VARIABLE_LOCALITY 862 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
924 bool 863 bool
925 864
926 config NUMA_BALANCING 865 config NUMA_BALANCING
927 bool "Memory placement aware NUMA sche 866 bool "Memory placement aware NUMA scheduler"
928 depends on ARCH_SUPPORTS_NUMA_BALANCIN 867 depends on ARCH_SUPPORTS_NUMA_BALANCING
929 depends on !ARCH_WANT_NUMA_VARIABLE_LO 868 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
930 depends on SMP && NUMA && MIGRATION && !! 869 depends on SMP && NUMA && MIGRATION
931 help 870 help
932 This option adds support for automat 871 This option adds support for automatic NUMA aware memory/task placement.
933 The mechanism is quite primitive and 872 The mechanism is quite primitive and is based on migrating memory when
934 it has references to the node the ta 873 it has references to the node the task is running on.
935 874
936 This system will be inactive on UMA 875 This system will be inactive on UMA systems.
937 876
938 config NUMA_BALANCING_DEFAULT_ENABLED 877 config NUMA_BALANCING_DEFAULT_ENABLED
939 bool "Automatically enable NUMA aware 878 bool "Automatically enable NUMA aware memory/task placement"
940 default y 879 default y
941 depends on NUMA_BALANCING 880 depends on NUMA_BALANCING
942 help 881 help
943 If set, automatic NUMA balancing wil 882 If set, automatic NUMA balancing will be enabled if running on a NUMA
944 machine. 883 machine.
945 884
946 config SLAB_OBJ_EXT <<
947 bool <<
948 <<
949 menuconfig CGROUPS 885 menuconfig CGROUPS
950 bool "Control Group support" 886 bool "Control Group support"
951 select KERNFS 887 select KERNFS
952 help 888 help
953 This option adds support for groupin 889 This option adds support for grouping sets of processes together, for
954 use with process control subsystems 890 use with process control subsystems such as Cpusets, CFS, memory
955 controls or device isolation. 891 controls or device isolation.
956 See 892 See
957 - Documentation/scheduler/sche 893 - Documentation/scheduler/sched-design-CFS.rst (CFS)
958 - Documentation/admin-guide/cg 894 - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation
959 and 895 and resource control)
960 896
961 Say N if unsure. 897 Say N if unsure.
962 898
963 if CGROUPS 899 if CGROUPS
964 900
965 config PAGE_COUNTER 901 config PAGE_COUNTER
966 bool 902 bool
967 903
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 904 config MEMCG
979 bool "Memory controller" 905 bool "Memory controller"
980 select PAGE_COUNTER 906 select PAGE_COUNTER
981 select EVENTFD 907 select EVENTFD
982 select SLAB_OBJ_EXT <<
983 help 908 help
984 Provides control over the memory foo 909 Provides control over the memory footprint of tasks in a cgroup.
985 910
986 config MEMCG_V1 !! 911 config MEMCG_SWAP
987 bool "Legacy cgroup v1 memory controll !! 912 bool
988 depends on MEMCG !! 913 depends on MEMCG && SWAP
989 default n !! 914 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 915
1001 Say N if unsure. !! 916 config MEMCG_KMEM
>> 917 bool
>> 918 depends on MEMCG && !SLOB
>> 919 default y
1002 920
1003 config BLK_CGROUP 921 config BLK_CGROUP
1004 bool "IO controller" 922 bool "IO controller"
1005 depends on BLOCK 923 depends on BLOCK
1006 default n 924 default n
1007 help 925 help
1008 Generic block IO controller cgroup in 926 Generic block IO controller cgroup interface. This is the common
1009 cgroup interface which should be used 927 cgroup interface which should be used by various IO controlling
1010 policies. 928 policies.
1011 929
1012 Currently, CFQ IO scheduler uses it t 930 Currently, CFQ IO scheduler uses it to recognize task groups and
1013 control disk bandwidth allocation (pr 931 control disk bandwidth allocation (proportional time slice allocation)
1014 to such task groups. It is also used 932 to such task groups. It is also used by bio throttling logic in
1015 block layer to implement upper limit 933 block layer to implement upper limit in IO rates on a device.
1016 934
1017 This option only enables generic Bloc 935 This option only enables generic Block IO controller infrastructure.
1018 One needs to also enable actual IO co 936 One needs to also enable actual IO controlling logic/policy. For
1019 enabling proportional weight division 937 enabling proportional weight division of disk bandwidth in CFQ, set
1020 CONFIG_BFQ_GROUP_IOSCHED=y; for enabl 938 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1021 CONFIG_BLK_DEV_THROTTLING=y. 939 CONFIG_BLK_DEV_THROTTLING=y.
1022 940
1023 See Documentation/admin-guide/cgroup- 941 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information.
1024 942
1025 config CGROUP_WRITEBACK 943 config CGROUP_WRITEBACK
1026 bool 944 bool
1027 depends on MEMCG && BLK_CGROUP 945 depends on MEMCG && BLK_CGROUP
1028 default y 946 default y
1029 947
1030 menuconfig CGROUP_SCHED 948 menuconfig CGROUP_SCHED
1031 bool "CPU controller" 949 bool "CPU controller"
1032 default n 950 default n
1033 help 951 help
1034 This feature lets CPU scheduler rec 952 This feature lets CPU scheduler recognize task groups and control CPU
1035 bandwidth allocation to such task g 953 bandwidth allocation to such task groups. It uses cgroups to group
1036 tasks. 954 tasks.
1037 955
1038 if CGROUP_SCHED 956 if CGROUP_SCHED
1039 config GROUP_SCHED_WEIGHT <<
1040 def_bool n <<
1041 <<
1042 config FAIR_GROUP_SCHED 957 config FAIR_GROUP_SCHED
1043 bool "Group scheduling for SCHED_OTHE 958 bool "Group scheduling for SCHED_OTHER"
1044 depends on CGROUP_SCHED 959 depends on CGROUP_SCHED
1045 select GROUP_SCHED_WEIGHT <<
1046 default CGROUP_SCHED 960 default CGROUP_SCHED
1047 961
1048 config CFS_BANDWIDTH 962 config CFS_BANDWIDTH
1049 bool "CPU bandwidth provisioning for 963 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1050 depends on FAIR_GROUP_SCHED 964 depends on FAIR_GROUP_SCHED
1051 default n 965 default n
1052 help 966 help
1053 This option allows users to define 967 This option allows users to define CPU bandwidth rates (limits) for
1054 tasks running within the fair group 968 tasks running within the fair group scheduler. Groups with no limit
1055 set are considered to be unconstrai 969 set are considered to be unconstrained and will run with no
1056 restriction. 970 restriction.
1057 See Documentation/scheduler/sched-b 971 See Documentation/scheduler/sched-bwc.rst for more information.
1058 972
1059 config RT_GROUP_SCHED 973 config RT_GROUP_SCHED
1060 bool "Group scheduling for SCHED_RR/F 974 bool "Group scheduling for SCHED_RR/FIFO"
1061 depends on CGROUP_SCHED 975 depends on CGROUP_SCHED
1062 default n 976 default n
1063 help 977 help
1064 This feature lets you explicitly al 978 This feature lets you explicitly allocate real CPU bandwidth
1065 to task groups. If enabled, it will 979 to task groups. If enabled, it will also make it impossible to
1066 schedule realtime tasks for non-roo 980 schedule realtime tasks for non-root users until you allocate
1067 realtime bandwidth for them. 981 realtime bandwidth for them.
1068 See Documentation/scheduler/sched-r 982 See Documentation/scheduler/sched-rt-group.rst for more information.
1069 983
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 984 endif #CGROUP_SCHED
1077 985
1078 config SCHED_MM_CID <<
1079 def_bool y <<
1080 depends on SMP && RSEQ <<
1081 <<
1082 config UCLAMP_TASK_GROUP 986 config UCLAMP_TASK_GROUP
1083 bool "Utilization clamping per group 987 bool "Utilization clamping per group of tasks"
1084 depends on CGROUP_SCHED 988 depends on CGROUP_SCHED
1085 depends on UCLAMP_TASK 989 depends on UCLAMP_TASK
1086 default n 990 default n
1087 help 991 help
1088 This feature enables the scheduler 992 This feature enables the scheduler to track the clamped utilization
1089 of each CPU based on RUNNABLE tasks 993 of each CPU based on RUNNABLE tasks currently scheduled on that CPU.
1090 994
1091 When this option is enabled, the us 995 When this option is enabled, the user can specify a min and max
1092 CPU bandwidth which is allowed for 996 CPU bandwidth which is allowed for each single task in a group.
1093 The max bandwidth allows to clamp t 997 The max bandwidth allows to clamp the maximum frequency a task
1094 can use, while the min bandwidth al 998 can use, while the min bandwidth allows to define a minimum
1095 frequency a task will always use. 999 frequency a task will always use.
1096 1000
1097 When task group based utilization c 1001 When task group based utilization clamping is enabled, an eventually
1098 specified task-specific clamp value 1002 specified task-specific clamp value is constrained by the cgroup
1099 specified clamp value. Both minimum 1003 specified clamp value. Both minimum and maximum task clamping cannot
1100 be bigger than the corresponding cl 1004 be bigger than the corresponding clamping defined at task group level.
1101 1005
1102 If in doubt, say N. 1006 If in doubt, say N.
1103 1007
1104 config CGROUP_PIDS 1008 config CGROUP_PIDS
1105 bool "PIDs controller" 1009 bool "PIDs controller"
1106 help 1010 help
1107 Provides enforcement of process num 1011 Provides enforcement of process number limits in the scope of a
1108 cgroup. Any attempt to fork more pr 1012 cgroup. Any attempt to fork more processes than is allowed in the
1109 cgroup will fail. PIDs are fundamen 1013 cgroup will fail. PIDs are fundamentally a global resource because it
1110 is fairly trivial to reach PID exha 1014 is fairly trivial to reach PID exhaustion before you reach even a
1111 conservative kmemcg limit. As a res 1015 conservative kmemcg limit. As a result, it is possible to grind a
1112 system to halt without being limite 1016 system to halt without being limited by other cgroup policies. The
1113 PIDs controller is designed to stop 1017 PIDs controller is designed to stop this from happening.
1114 1018
1115 It should be noted that organisatio 1019 It should be noted that organisational operations (such as attaching
1116 to a cgroup hierarchy) will *not* b 1020 to a cgroup hierarchy) will *not* be blocked by the PIDs controller,
1117 since the PIDs limit only affects a 1021 since the PIDs limit only affects a process's ability to fork, not to
1118 attach to a cgroup. 1022 attach to a cgroup.
1119 1023
1120 config CGROUP_RDMA 1024 config CGROUP_RDMA
1121 bool "RDMA controller" 1025 bool "RDMA controller"
1122 help 1026 help
1123 Provides enforcement of RDMA resour 1027 Provides enforcement of RDMA resources defined by IB stack.
1124 It is fairly easy for consumers to 1028 It is fairly easy for consumers to exhaust RDMA resources, which
1125 can result into resource unavailabi 1029 can result into resource unavailability to other consumers.
1126 RDMA controller is designed to stop 1030 RDMA controller is designed to stop this from happening.
1127 Attaching processes with active RDM 1031 Attaching processes with active RDMA resources to the cgroup
1128 hierarchy is allowed even if can cr 1032 hierarchy is allowed even if can cross the hierarchy's limit.
1129 1033
1130 config CGROUP_FREEZER 1034 config CGROUP_FREEZER
1131 bool "Freezer controller" 1035 bool "Freezer controller"
1132 help 1036 help
1133 Provides a way to freeze and unfree 1037 Provides a way to freeze and unfreeze all tasks in a
1134 cgroup. 1038 cgroup.
1135 1039
1136 This option affects the ORIGINAL cg 1040 This option affects the ORIGINAL cgroup interface. The cgroup2 memory
1137 controller includes important in-ke 1041 controller includes important in-kernel memory consumers per default.
1138 1042
1139 If you're using cgroup2, say N. 1043 If you're using cgroup2, say N.
1140 1044
1141 config CGROUP_HUGETLB 1045 config CGROUP_HUGETLB
1142 bool "HugeTLB controller" 1046 bool "HugeTLB controller"
1143 depends on HUGETLB_PAGE 1047 depends on HUGETLB_PAGE
1144 select PAGE_COUNTER 1048 select PAGE_COUNTER
1145 default n 1049 default n
1146 help 1050 help
1147 Provides a cgroup controller for Hu 1051 Provides a cgroup controller for HugeTLB pages.
1148 When you enable this, you can put a 1052 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1149 The limit is enforced during page f 1053 The limit is enforced during page fault. Since HugeTLB doesn't
1150 support page reclaim, enforcing the 1054 support page reclaim, enforcing the limit at page fault time implies
1151 that, the application will get SIGB 1055 that, the application will get SIGBUS signal if it tries to access
1152 HugeTLB pages beyond its limit. Thi 1056 HugeTLB pages beyond its limit. This requires the application to know
1153 beforehand how much HugeTLB pages i 1057 beforehand how much HugeTLB pages it would require for its use. The
1154 control group is tracked in the thi 1058 control group is tracked in the third page lru pointer. This means
1155 that we cannot use the controller w 1059 that we cannot use the controller with huge page less than 3 pages.
1156 1060
1157 config CPUSETS 1061 config CPUSETS
1158 bool "Cpuset controller" 1062 bool "Cpuset controller"
1159 depends on SMP 1063 depends on SMP
1160 help 1064 help
1161 This option will let you create and 1065 This option will let you create and manage CPUSETs which
1162 allow dynamically partitioning a sy 1066 allow dynamically partitioning a system into sets of CPUs and
1163 Memory Nodes and assigning tasks to 1067 Memory Nodes and assigning tasks to run only within those sets.
1164 This is primarily useful on large S 1068 This is primarily useful on large SMP or NUMA systems.
1165 1069
1166 Say N if unsure. 1070 Say N if unsure.
1167 1071
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 1072 config PROC_PID_CPUSET
1182 bool "Include legacy /proc/<pid>/cpus 1073 bool "Include legacy /proc/<pid>/cpuset file"
1183 depends on CPUSETS 1074 depends on CPUSETS
1184 default y 1075 default y
1185 1076
1186 config CGROUP_DEVICE 1077 config CGROUP_DEVICE
1187 bool "Device controller" 1078 bool "Device controller"
1188 help 1079 help
1189 Provides a cgroup controller implem 1080 Provides a cgroup controller implementing whitelists for
1190 devices which a process in the cgro 1081 devices which a process in the cgroup can mknod or open.
1191 1082
1192 config CGROUP_CPUACCT 1083 config CGROUP_CPUACCT
1193 bool "Simple CPU accounting controlle 1084 bool "Simple CPU accounting controller"
1194 help 1085 help
1195 Provides a simple controller for mo 1086 Provides a simple controller for monitoring the
1196 total CPU consumed by the tasks in 1087 total CPU consumed by the tasks in a cgroup.
1197 1088
1198 config CGROUP_PERF 1089 config CGROUP_PERF
1199 bool "Perf controller" 1090 bool "Perf controller"
1200 depends on PERF_EVENTS 1091 depends on PERF_EVENTS
1201 help 1092 help
1202 This option extends the perf per-cp 1093 This option extends the perf per-cpu mode to restrict monitoring
1203 to threads which belong to the cgro 1094 to threads which belong to the cgroup specified and run on the
1204 designated cpu. Or this can be use 1095 designated cpu. Or this can be used to have cgroup ID in samples
1205 so that it can monitor performance 1096 so that it can monitor performance events among cgroups.
1206 1097
1207 Say N if unsure. 1098 Say N if unsure.
1208 1099
1209 config CGROUP_BPF 1100 config CGROUP_BPF
1210 bool "Support for eBPF programs attac 1101 bool "Support for eBPF programs attached to cgroups"
1211 depends on BPF_SYSCALL 1102 depends on BPF_SYSCALL
1212 select SOCK_CGROUP_DATA 1103 select SOCK_CGROUP_DATA
1213 help 1104 help
1214 Allow attaching eBPF programs to a 1105 Allow attaching eBPF programs to a cgroup using the bpf(2)
1215 syscall command BPF_PROG_ATTACH. 1106 syscall command BPF_PROG_ATTACH.
1216 1107
1217 In which context these programs are 1108 In which context these programs are accessed depends on the type
1218 of attachment. For instance, progra 1109 of attachment. For instance, programs that are attached using
1219 BPF_CGROUP_INET_INGRESS will be exe 1110 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
1220 inet sockets. 1111 inet sockets.
1221 1112
1222 config CGROUP_MISC <<
1223 bool "Misc resource controller" <<
1224 default n <<
1225 help <<
1226 Provides a controller for miscellan <<
1227 <<
1228 Miscellaneous scalar resources are <<
1229 which cannot be abstracted like the <<
1230 tracks and limits the miscellaneous <<
1231 attached to a cgroup hierarchy. <<
1232 <<
1233 For more information, please check <<
1234 /Documentation/admin-guide/cgroup-v <<
1235 <<
1236 config CGROUP_DEBUG 1113 config CGROUP_DEBUG
1237 bool "Debug controller" 1114 bool "Debug controller"
1238 default n 1115 default n
1239 depends on DEBUG_KERNEL 1116 depends on DEBUG_KERNEL
1240 help 1117 help
1241 This option enables a simple contro 1118 This option enables a simple controller that exports
1242 debugging information about the cgr 1119 debugging information about the cgroups framework. This
1243 controller is for control cgroup de 1120 controller is for control cgroup debugging only. Its
1244 interfaces are not stable. 1121 interfaces are not stable.
1245 1122
1246 Say N. 1123 Say N.
1247 1124
1248 config SOCK_CGROUP_DATA 1125 config SOCK_CGROUP_DATA
1249 bool 1126 bool
1250 default n 1127 default n
1251 1128
1252 endif # CGROUPS 1129 endif # CGROUPS
1253 1130
1254 menuconfig NAMESPACES 1131 menuconfig NAMESPACES
1255 bool "Namespaces support" if EXPERT 1132 bool "Namespaces support" if EXPERT
1256 depends on MULTIUSER 1133 depends on MULTIUSER
1257 default !EXPERT 1134 default !EXPERT
1258 help 1135 help
1259 Provides the way to make tasks work 1136 Provides the way to make tasks work with different objects using
1260 the same id. For example same IPC i 1137 the same id. For example same IPC id may refer to different objects
1261 or same user id or pid may refer to 1138 or same user id or pid may refer to different tasks when used in
1262 different namespaces. 1139 different namespaces.
1263 1140
1264 if NAMESPACES 1141 if NAMESPACES
1265 1142
1266 config UTS_NS 1143 config UTS_NS
1267 bool "UTS namespace" 1144 bool "UTS namespace"
1268 default y 1145 default y
1269 help 1146 help
1270 In this namespace tasks see differe 1147 In this namespace tasks see different info provided with the
1271 uname() system call 1148 uname() system call
1272 1149
1273 config TIME_NS 1150 config TIME_NS
1274 bool "TIME namespace" 1151 bool "TIME namespace"
1275 depends on GENERIC_VDSO_TIME_NS 1152 depends on GENERIC_VDSO_TIME_NS
1276 default y 1153 default y
1277 help 1154 help
1278 In this namespace boottime and mono 1155 In this namespace boottime and monotonic clocks can be set.
1279 The time will keep going with the s 1156 The time will keep going with the same pace.
1280 1157
1281 config IPC_NS 1158 config IPC_NS
1282 bool "IPC namespace" 1159 bool "IPC namespace"
1283 depends on (SYSVIPC || POSIX_MQUEUE) 1160 depends on (SYSVIPC || POSIX_MQUEUE)
1284 default y 1161 default y
1285 help 1162 help
1286 In this namespace tasks work with I 1163 In this namespace tasks work with IPC ids which correspond to
1287 different IPC objects in different 1164 different IPC objects in different namespaces.
1288 1165
1289 config USER_NS 1166 config USER_NS
1290 bool "User namespace" 1167 bool "User namespace"
1291 default n 1168 default n
1292 help 1169 help
1293 This allows containers, i.e. vserve 1170 This allows containers, i.e. vservers, to use user namespaces
1294 to provide different user info for 1171 to provide different user info for different servers.
1295 1172
1296 When user namespaces are enabled in 1173 When user namespaces are enabled in the kernel it is
1297 recommended that the MEMCG option a 1174 recommended that the MEMCG option also be enabled and that
1298 user-space use the memory control g 1175 user-space use the memory control groups to limit the amount
1299 of memory a memory unprivileged use 1176 of memory a memory unprivileged users can use.
1300 1177
1301 If unsure, say N. 1178 If unsure, say N.
1302 1179
1303 config PID_NS 1180 config PID_NS
1304 bool "PID Namespaces" 1181 bool "PID Namespaces"
1305 default y 1182 default y
1306 help 1183 help
1307 Support process id namespaces. Thi 1184 Support process id namespaces. This allows having multiple
1308 processes with the same pid as long 1185 processes with the same pid as long as they are in different
1309 pid namespaces. This is a building 1186 pid namespaces. This is a building block of containers.
1310 1187
1311 config NET_NS 1188 config NET_NS
1312 bool "Network namespace" 1189 bool "Network namespace"
1313 depends on NET 1190 depends on NET
1314 default y 1191 default y
1315 help 1192 help
1316 Allow user space to create what app 1193 Allow user space to create what appear to be multiple instances
1317 of the network stack. 1194 of the network stack.
1318 1195
1319 endif # NAMESPACES 1196 endif # NAMESPACES
1320 1197
1321 config CHECKPOINT_RESTORE 1198 config CHECKPOINT_RESTORE
1322 bool "Checkpoint/restore support" 1199 bool "Checkpoint/restore support"
1323 depends on PROC_FS <<
1324 select PROC_CHILDREN 1200 select PROC_CHILDREN
1325 select KCMP 1201 select KCMP
1326 default n 1202 default n
1327 help 1203 help
1328 Enables additional kernel features 1204 Enables additional kernel features in a sake of checkpoint/restore.
1329 In particular it adds auxiliary prc 1205 In particular it adds auxiliary prctl codes to setup process text,
1330 data and heap segment sizes, and a 1206 data and heap segment sizes, and a few additional /proc filesystem
1331 entries. 1207 entries.
1332 1208
1333 If unsure, say N here. 1209 If unsure, say N here.
1334 1210
1335 config SCHED_AUTOGROUP 1211 config SCHED_AUTOGROUP
1336 bool "Automatic process group schedul 1212 bool "Automatic process group scheduling"
1337 select CGROUPS 1213 select CGROUPS
1338 select CGROUP_SCHED 1214 select CGROUP_SCHED
1339 select FAIR_GROUP_SCHED 1215 select FAIR_GROUP_SCHED
1340 help 1216 help
1341 This option optimizes the scheduler 1217 This option optimizes the scheduler for common desktop workloads by
1342 automatically creating and populati 1218 automatically creating and populating task groups. This separation
1343 of workloads isolates aggressive CP 1219 of workloads isolates aggressive CPU burners (like build jobs) from
1344 desktop applications. Task group a 1220 desktop applications. Task group autogeneration is currently based
1345 upon task session. 1221 upon task session.
1346 1222
>> 1223 config SYSFS_DEPRECATED
>> 1224 bool "Enable deprecated sysfs features to support old userspace tools"
>> 1225 depends on SYSFS
>> 1226 default n
>> 1227 help
>> 1228 This option adds code that switches the layout of the "block" class
>> 1229 devices, to not show up in /sys/class/block/, but only in
>> 1230 /sys/block/.
>> 1231
>> 1232 This switch is only active when the sysfs.deprecated=1 boot option is
>> 1233 passed or the SYSFS_DEPRECATED_V2 option is set.
>> 1234
>> 1235 This option allows new kernels to run on old distributions and tools,
>> 1236 which might get confused by /sys/class/block/. Since 2007/2008 all
>> 1237 major distributions and tools handle this just fine.
>> 1238
>> 1239 Recent distributions and userspace tools after 2009/2010 depend on
>> 1240 the existence of /sys/class/block/, and will not work with this
>> 1241 option enabled.
>> 1242
>> 1243 Only if you are using a new kernel on an old distribution, you might
>> 1244 need to say Y here.
>> 1245
>> 1246 config SYSFS_DEPRECATED_V2
>> 1247 bool "Enable deprecated sysfs features by default"
>> 1248 default n
>> 1249 depends on SYSFS
>> 1250 depends on SYSFS_DEPRECATED
>> 1251 help
>> 1252 Enable deprecated sysfs by default.
>> 1253
>> 1254 See the CONFIG_SYSFS_DEPRECATED option for more details about this
>> 1255 option.
>> 1256
>> 1257 Only if you are using a new kernel on an old distribution, you might
>> 1258 need to say Y here. Even then, odds are you would not need it
>> 1259 enabled, you can always pass the boot option if absolutely necessary.
>> 1260
1347 config RELAY 1261 config RELAY
1348 bool "Kernel->user space relay suppor 1262 bool "Kernel->user space relay support (formerly relayfs)"
1349 select IRQ_WORK 1263 select IRQ_WORK
1350 help 1264 help
1351 This option enables support for rel 1265 This option enables support for relay interface support in
1352 certain file systems (such as debug 1266 certain file systems (such as debugfs).
1353 It is designed to provide an effici 1267 It is designed to provide an efficient mechanism for tools and
1354 facilities to relay large amounts o 1268 facilities to relay large amounts of data from kernel space to
1355 user space. 1269 user space.
1356 1270
1357 If unsure, say N. 1271 If unsure, say N.
1358 1272
1359 config BLK_DEV_INITRD 1273 config BLK_DEV_INITRD
1360 bool "Initial RAM filesystem and RAM 1274 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1361 help 1275 help
1362 The initial RAM filesystem is a ram 1276 The initial RAM filesystem is a ramfs which is loaded by the
1363 boot loader (loadlin or lilo) and t 1277 boot loader (loadlin or lilo) and that is mounted as root
1364 before the normal boot procedure. I 1278 before the normal boot procedure. It is typically used to
1365 load modules needed to mount the "r 1279 load modules needed to mount the "real" root file system,
1366 etc. See <file:Documentation/admin- 1280 etc. See <file:Documentation/admin-guide/initrd.rst> for details.
1367 1281
1368 If RAM disk support (BLK_DEV_RAM) i 1282 If RAM disk support (BLK_DEV_RAM) is also included, this
1369 also enables initial RAM disk (init 1283 also enables initial RAM disk (initrd) support and adds
1370 15 Kbytes (more on some other archi 1284 15 Kbytes (more on some other architectures) to the kernel size.
1371 1285
1372 If unsure say Y. 1286 If unsure say Y.
1373 1287
1374 if BLK_DEV_INITRD 1288 if BLK_DEV_INITRD
1375 1289
1376 source "usr/Kconfig" 1290 source "usr/Kconfig"
1377 1291
1378 endif 1292 endif
1379 1293
1380 config BOOT_CONFIG 1294 config BOOT_CONFIG
1381 bool "Boot config support" 1295 bool "Boot config support"
1382 select BLK_DEV_INITRD if !BOOT_CONFIG !! 1296 select BLK_DEV_INITRD
1383 help 1297 help
1384 Extra boot config allows system adm 1298 Extra boot config allows system admin to pass a config file as
1385 complemental extension of kernel cm 1299 complemental extension of kernel cmdline when booting.
1386 The boot config file must be attach 1300 The boot config file must be attached at the end of initramfs
1387 with checksum, size and magic word. 1301 with checksum, size and magic word.
1388 See <file:Documentation/admin-guide 1302 See <file:Documentation/admin-guide/bootconfig.rst> for details.
1389 1303
1390 If unsure, say Y. 1304 If unsure, say Y.
1391 1305
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 1306 choice
1435 prompt "Compiler optimization level" 1307 prompt "Compiler optimization level"
1436 default CC_OPTIMIZE_FOR_PERFORMANCE 1308 default CC_OPTIMIZE_FOR_PERFORMANCE
1437 1309
1438 config CC_OPTIMIZE_FOR_PERFORMANCE 1310 config CC_OPTIMIZE_FOR_PERFORMANCE
1439 bool "Optimize for performance (-O2)" 1311 bool "Optimize for performance (-O2)"
1440 help 1312 help
1441 This is the default optimization le 1313 This is the default optimization level for the kernel, building
1442 with the "-O2" compiler flag for be 1314 with the "-O2" compiler flag for best performance and most
1443 helpful compile-time warnings. 1315 helpful compile-time warnings.
1444 1316
>> 1317 config CC_OPTIMIZE_FOR_PERFORMANCE_O3
>> 1318 bool "Optimize more for performance (-O3)"
>> 1319 depends on ARC
>> 1320 help
>> 1321 Choosing this option will pass "-O3" to your compiler to optimize
>> 1322 the kernel yet more for performance.
>> 1323
1445 config CC_OPTIMIZE_FOR_SIZE 1324 config CC_OPTIMIZE_FOR_SIZE
1446 bool "Optimize for size (-Os)" 1325 bool "Optimize for size (-Os)"
1447 help 1326 help
1448 Choosing this option will pass "-Os 1327 Choosing this option will pass "-Os" to your compiler resulting
1449 in a smaller kernel. 1328 in a smaller kernel.
1450 1329
1451 endchoice 1330 endchoice
1452 1331
1453 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1332 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1454 bool 1333 bool
1455 help 1334 help
1456 This requires that the arch annotat 1335 This requires that the arch annotates or otherwise protects
1457 its external entry points from bein 1336 its external entry points from being discarded. Linker scripts
1458 must also merge .text.*, .data.*, a 1337 must also merge .text.*, .data.*, and .bss.* correctly into
1459 output sections. Care must be taken 1338 output sections. Care must be taken not to pull in unrelated
1460 sections (e.g., '.text.init'). Typi 1339 sections (e.g., '.text.init'). Typically '.' in section names
1461 is used to distinguish them from la 1340 is used to distinguish them from label names / C identifiers.
1462 1341
1463 config LD_DEAD_CODE_DATA_ELIMINATION 1342 config LD_DEAD_CODE_DATA_ELIMINATION
1464 bool "Dead code and data elimination 1343 bool "Dead code and data elimination (EXPERIMENTAL)"
1465 depends on HAVE_LD_DEAD_CODE_DATA_ELI 1344 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1466 depends on EXPERT 1345 depends on EXPERT
1467 depends on $(cc-option,-ffunction-sec 1346 depends on $(cc-option,-ffunction-sections -fdata-sections)
1468 depends on $(ld-option,--gc-sections) 1347 depends on $(ld-option,--gc-sections)
1469 help 1348 help
1470 Enable this if you want to do dead 1349 Enable this if you want to do dead code and data elimination with
1471 the linker by compiling with -ffunc 1350 the linker by compiling with -ffunction-sections -fdata-sections,
1472 and linking with --gc-sections. 1351 and linking with --gc-sections.
1473 1352
1474 This can reduce on disk and in-memo 1353 This can reduce on disk and in-memory size of the kernel
1475 code and static data, particularly 1354 code and static data, particularly for small configs and
1476 on small systems. This has the poss 1355 on small systems. This has the possibility of introducing
1477 silently broken kernel if the requi 1356 silently broken kernel if the required annotations are not
1478 present. This option is not well te 1357 present. This option is not well tested yet, so use at your
1479 own risk. 1358 own risk.
1480 1359
1481 config LD_ORPHAN_WARN 1360 config LD_ORPHAN_WARN
1482 def_bool y 1361 def_bool y
1483 depends on ARCH_WANT_LD_ORPHAN_WARN 1362 depends on ARCH_WANT_LD_ORPHAN_WARN
>> 1363 depends on !LD_IS_LLD || LLD_VERSION >= 110000
1484 depends on $(ld-option,--orphan-handl 1364 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 1365
1493 config SYSCTL 1366 config SYSCTL
1494 bool 1367 bool
1495 1368
1496 config HAVE_UID16 1369 config HAVE_UID16
1497 bool 1370 bool
1498 1371
1499 config SYSCTL_EXCEPTION_TRACE 1372 config SYSCTL_EXCEPTION_TRACE
1500 bool 1373 bool
1501 help 1374 help
1502 Enable support for /proc/sys/debug/ 1375 Enable support for /proc/sys/debug/exception-trace.
1503 1376
1504 config SYSCTL_ARCH_UNALIGN_NO_WARN 1377 config SYSCTL_ARCH_UNALIGN_NO_WARN
1505 bool 1378 bool
1506 help 1379 help
1507 Enable support for /proc/sys/kernel 1380 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1508 Allows arch to define/use @no_unali 1381 Allows arch to define/use @no_unaligned_warning to possibly warn
1509 about unaligned access emulation go 1382 about unaligned access emulation going on under the hood.
1510 1383
1511 config SYSCTL_ARCH_UNALIGN_ALLOW 1384 config SYSCTL_ARCH_UNALIGN_ALLOW
1512 bool 1385 bool
1513 help 1386 help
1514 Enable support for /proc/sys/kernel 1387 Enable support for /proc/sys/kernel/unaligned-trap
1515 Allows arches to define/use @unalig 1388 Allows arches to define/use @unaligned_enabled to runtime toggle
1516 the unaligned access emulation. 1389 the unaligned access emulation.
1517 see arch/parisc/kernel/unaligned.c 1390 see arch/parisc/kernel/unaligned.c for reference
1518 1391
1519 config HAVE_PCSPKR_PLATFORM 1392 config HAVE_PCSPKR_PLATFORM
1520 bool 1393 bool
1521 1394
>> 1395 # interpreter that classic socket filters depend on
>> 1396 config BPF
>> 1397 bool
>> 1398
1522 menuconfig EXPERT 1399 menuconfig EXPERT
1523 bool "Configure standard kernel featu 1400 bool "Configure standard kernel features (expert users)"
1524 # Unhide debug options, to make the o 1401 # Unhide debug options, to make the on-by-default options visible
1525 select DEBUG_KERNEL 1402 select DEBUG_KERNEL
1526 help 1403 help
1527 This option allows certain base ker 1404 This option allows certain base kernel options and settings
1528 to be disabled or tweaked. This is 1405 to be disabled or tweaked. This is for specialized
1529 environments which can tolerate a " 1406 environments which can tolerate a "non-standard" kernel.
1530 Only use this if you really know wh 1407 Only use this if you really know what you are doing.
1531 1408
1532 config UID16 1409 config UID16
1533 bool "Enable 16-bit UID system calls" 1410 bool "Enable 16-bit UID system calls" if EXPERT
1534 depends on HAVE_UID16 && MULTIUSER 1411 depends on HAVE_UID16 && MULTIUSER
1535 default y 1412 default y
1536 help 1413 help
1537 This enables the legacy 16-bit UID 1414 This enables the legacy 16-bit UID syscall wrappers.
1538 1415
1539 config MULTIUSER 1416 config MULTIUSER
1540 bool "Multiple users, groups and capa 1417 bool "Multiple users, groups and capabilities support" if EXPERT
1541 default y 1418 default y
1542 help 1419 help
1543 This option enables support for non 1420 This option enables support for non-root users, groups and
1544 capabilities. 1421 capabilities.
1545 1422
1546 If you say N here, all processes wi 1423 If you say N here, all processes will run with UID 0, GID 0, and all
1547 possible capabilities. Saying N he 1424 possible capabilities. Saying N here also compiles out support for
1548 system calls related to UIDs, GIDs, 1425 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1549 setgid, and capset. 1426 setgid, and capset.
1550 1427
1551 If unsure, say Y here. 1428 If unsure, say Y here.
1552 1429
1553 config SGETMASK_SYSCALL 1430 config SGETMASK_SYSCALL
1554 bool "sgetmask/ssetmask syscalls supp 1431 bool "sgetmask/ssetmask syscalls support" if EXPERT
1555 default PARISC || M68K || PPC || MIPS !! 1432 def_bool PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH
1556 help 1433 help
1557 sys_sgetmask and sys_ssetmask are o 1434 sys_sgetmask and sys_ssetmask are obsolete system calls
1558 no longer supported in libc but sti 1435 no longer supported in libc but still enabled by default in some
1559 architectures. 1436 architectures.
1560 1437
1561 If unsure, leave the default option 1438 If unsure, leave the default option here.
1562 1439
1563 config SYSFS_SYSCALL 1440 config SYSFS_SYSCALL
1564 bool "Sysfs syscall support" if EXPER 1441 bool "Sysfs syscall support" if EXPERT
1565 default y 1442 default y
1566 help 1443 help
1567 sys_sysfs is an obsolete system cal 1444 sys_sysfs is an obsolete system call no longer supported in libc.
1568 Note that disabling this option is 1445 Note that disabling this option is more secure but might break
1569 compatibility with some systems. 1446 compatibility with some systems.
1570 1447
1571 If unsure say Y here. 1448 If unsure say Y here.
1572 1449
1573 config FHANDLE 1450 config FHANDLE
1574 bool "open by fhandle syscalls" if EX 1451 bool "open by fhandle syscalls" if EXPERT
1575 select EXPORTFS 1452 select EXPORTFS
1576 default y 1453 default y
1577 help 1454 help
1578 If you say Y here, a user level pro 1455 If you say Y here, a user level program will be able to map
1579 file names to handle and then later 1456 file names to handle and then later use the handle for
1580 different file system operations. T 1457 different file system operations. This is useful in implementing
1581 userspace file servers, which now t 1458 userspace file servers, which now track files using handles instead
1582 of names. The handle would remain t 1459 of names. The handle would remain the same even if file names
1583 get renamed. Enables open_by_handle 1460 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
1584 syscalls. 1461 syscalls.
1585 1462
1586 config POSIX_TIMERS 1463 config POSIX_TIMERS
1587 bool "Posix Clocks & timers" if EXPER 1464 bool "Posix Clocks & timers" if EXPERT
1588 default y 1465 default y
1589 help 1466 help
1590 This includes native support for PO 1467 This includes native support for POSIX timers to the kernel.
1591 Some embedded systems have no use f 1468 Some embedded systems have no use for them and therefore they
1592 can be configured out to reduce the 1469 can be configured out to reduce the size of the kernel image.
1593 1470
1594 When this option is disabled, the f 1471 When this option is disabled, the following syscalls won't be
1595 available: timer_create, timer_gett 1472 available: timer_create, timer_gettime: timer_getoverrun,
1596 timer_settime, timer_delete, clock_ 1473 timer_settime, timer_delete, clock_adjtime, getitimer,
1597 setitimer, alarm. Furthermore, the 1474 setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
1598 clock_getres and clock_nanosleep sy 1475 clock_getres and clock_nanosleep syscalls will be limited to
1599 CLOCK_REALTIME, CLOCK_MONOTONIC and 1476 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
1600 1477
1601 If unsure say y. 1478 If unsure say y.
1602 1479
1603 config PRINTK 1480 config PRINTK
1604 default y 1481 default y
1605 bool "Enable support for printk" if E 1482 bool "Enable support for printk" if EXPERT
1606 select IRQ_WORK 1483 select IRQ_WORK
1607 help 1484 help
1608 This option enables normal printk s 1485 This option enables normal printk support. Removing it
1609 eliminates most of the message stri 1486 eliminates most of the message strings from the kernel image
1610 and makes the kernel more or less s 1487 and makes the kernel more or less silent. As this makes it
1611 very difficult to diagnose system p 1488 very difficult to diagnose system problems, saying N here is
1612 strongly discouraged. 1489 strongly discouraged.
1613 1490
>> 1491 config PRINTK_NMI
>> 1492 def_bool y
>> 1493 depends on PRINTK
>> 1494 depends on HAVE_NMI
>> 1495
1614 config BUG 1496 config BUG
1615 bool "BUG() support" if EXPERT 1497 bool "BUG() support" if EXPERT
1616 default y 1498 default y
1617 help 1499 help
1618 Disabling this option eliminates su 1500 Disabling this option eliminates support for BUG and WARN, reducing
1619 the size of your kernel image and p 1501 the size of your kernel image and potentially quietly ignoring
1620 numerous fatal conditions. You shou 1502 numerous fatal conditions. You should only consider disabling this
1621 option for embedded systems with no 1503 option for embedded systems with no facilities for reporting errors.
1622 Just say Y. 1504 Just say Y.
1623 1505
1624 config ELF_CORE 1506 config ELF_CORE
1625 depends on COREDUMP 1507 depends on COREDUMP
1626 default y 1508 default y
1627 bool "Enable ELF core dumps" if EXPER 1509 bool "Enable ELF core dumps" if EXPERT
1628 help 1510 help
1629 Enable support for generating core 1511 Enable support for generating core dumps. Disabling saves about 4k.
1630 1512
1631 1513
1632 config PCSPKR_PLATFORM 1514 config PCSPKR_PLATFORM
1633 bool "Enable PC-Speaker support" if E 1515 bool "Enable PC-Speaker support" if EXPERT
1634 depends on HAVE_PCSPKR_PLATFORM 1516 depends on HAVE_PCSPKR_PLATFORM
1635 select I8253_LOCK 1517 select I8253_LOCK
1636 default y 1518 default y
1637 help 1519 help
1638 This option allows to disable the i 1520 This option allows to disable the internal PC-Speaker
1639 support, saving some memory. 1521 support, saving some memory.
1640 1522
1641 config BASE_SMALL !! 1523 config BASE_FULL
1642 bool "Enable smaller-sized data struc !! 1524 default y
>> 1525 bool "Enable full-sized data structures for core" if EXPERT
1643 help 1526 help
1644 Enabling this option reduces the si !! 1527 Disabling this option reduces the size of miscellaneous core
1645 kernel data structures. This saves 1528 kernel data structures. This saves memory on small machines,
1646 but may reduce performance. 1529 but may reduce performance.
1647 1530
1648 config FUTEX 1531 config FUTEX
1649 bool "Enable futex support" if EXPERT 1532 bool "Enable futex support" if EXPERT
1650 depends on !(SPARC32 && SMP) <<
1651 default y 1533 default y
1652 imply RT_MUTEXES 1534 imply RT_MUTEXES
1653 help 1535 help
1654 Disabling this option will cause th 1536 Disabling this option will cause the kernel to be built without
1655 support for "fast userspace mutexes 1537 support for "fast userspace mutexes". The resulting kernel may not
1656 run glibc-based applications correc 1538 run glibc-based applications correctly.
1657 1539
1658 config FUTEX_PI 1540 config FUTEX_PI
1659 bool 1541 bool
1660 depends on FUTEX && RT_MUTEXES 1542 depends on FUTEX && RT_MUTEXES
1661 default y 1543 default y
1662 1544
>> 1545 config HAVE_FUTEX_CMPXCHG
>> 1546 bool
>> 1547 depends on FUTEX
>> 1548 help
>> 1549 Architectures should select this if futex_atomic_cmpxchg_inatomic()
>> 1550 is implemented and always working. This removes a couple of runtime
>> 1551 checks.
>> 1552
1663 config EPOLL 1553 config EPOLL
1664 bool "Enable eventpoll support" if EX 1554 bool "Enable eventpoll support" if EXPERT
1665 default y 1555 default y
1666 help 1556 help
1667 Disabling this option will cause th 1557 Disabling this option will cause the kernel to be built without
1668 support for epoll family of system 1558 support for epoll family of system calls.
1669 1559
1670 config SIGNALFD 1560 config SIGNALFD
1671 bool "Enable signalfd() system call" 1561 bool "Enable signalfd() system call" if EXPERT
1672 default y 1562 default y
1673 help 1563 help
1674 Enable the signalfd() system call t 1564 Enable the signalfd() system call that allows to receive signals
1675 on a file descriptor. 1565 on a file descriptor.
1676 1566
1677 If unsure, say Y. 1567 If unsure, say Y.
1678 1568
1679 config TIMERFD 1569 config TIMERFD
1680 bool "Enable timerfd() system call" i 1570 bool "Enable timerfd() system call" if EXPERT
1681 default y 1571 default y
1682 help 1572 help
1683 Enable the timerfd() system call th 1573 Enable the timerfd() system call that allows to receive timer
1684 events on a file descriptor. 1574 events on a file descriptor.
1685 1575
1686 If unsure, say Y. 1576 If unsure, say Y.
1687 1577
1688 config EVENTFD 1578 config EVENTFD
1689 bool "Enable eventfd() system call" i 1579 bool "Enable eventfd() system call" if EXPERT
1690 default y 1580 default y
1691 help 1581 help
1692 Enable the eventfd() system call th 1582 Enable the eventfd() system call that allows to receive both
1693 kernel notification (ie. KAIO) or u 1583 kernel notification (ie. KAIO) or userspace notifications.
1694 1584
1695 If unsure, say Y. 1585 If unsure, say Y.
1696 1586
1697 config SHMEM 1587 config SHMEM
1698 bool "Use full shmem filesystem" if E 1588 bool "Use full shmem filesystem" if EXPERT
1699 default y 1589 default y
1700 depends on MMU 1590 depends on MMU
1701 help 1591 help
1702 The shmem is an internal filesystem 1592 The shmem is an internal filesystem used to manage shared memory.
1703 It is backed by swap and manages re 1593 It is backed by swap and manages resource limits. It is also exported
1704 to userspace as tmpfs if TMPFS is e 1594 to userspace as tmpfs if TMPFS is enabled. Disabling this
1705 option replaces shmem and tmpfs wit 1595 option replaces shmem and tmpfs with the much simpler ramfs code,
1706 which may be appropriate on small s 1596 which may be appropriate on small systems without swap.
1707 1597
1708 config AIO 1598 config AIO
1709 bool "Enable AIO support" if EXPERT 1599 bool "Enable AIO support" if EXPERT
1710 default y 1600 default y
1711 help 1601 help
1712 This option enables POSIX asynchron 1602 This option enables POSIX asynchronous I/O which may by used
1713 by some high performance threaded a 1603 by some high performance threaded applications. Disabling
1714 this option saves about 7k. 1604 this option saves about 7k.
1715 1605
1716 config IO_URING 1606 config IO_URING
1717 bool "Enable IO uring support" if EXP 1607 bool "Enable IO uring support" if EXPERT
1718 select IO_WQ 1608 select IO_WQ
1719 default y 1609 default y
1720 help 1610 help
1721 This option enables support for the 1611 This option enables support for the io_uring interface, enabling
1722 applications to submit and complete 1612 applications to submit and complete IO through submission and
1723 completion rings that are shared be 1613 completion rings that are shared between the kernel and application.
1724 1614
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 1615 config ADVISE_SYSCALLS
1739 bool "Enable madvise/fadvise syscalls 1616 bool "Enable madvise/fadvise syscalls" if EXPERT
1740 default y 1617 default y
1741 help 1618 help
1742 This option enables the madvise and 1619 This option enables the madvise and fadvise syscalls, used by
1743 applications to advise the kernel a 1620 applications to advise the kernel about their future memory or file
1744 usage, improving performance. If bu 1621 usage, improving performance. If building an embedded system where no
1745 applications use these syscalls, yo 1622 applications use these syscalls, you can disable this option to save
1746 space. 1623 space.
1747 1624
>> 1625 config HAVE_ARCH_USERFAULTFD_WP
>> 1626 bool
>> 1627 help
>> 1628 Arch has userfaultfd write protection support
>> 1629
1748 config MEMBARRIER 1630 config MEMBARRIER
1749 bool "Enable membarrier() system call 1631 bool "Enable membarrier() system call" if EXPERT
1750 default y 1632 default y
1751 help 1633 help
1752 Enable the membarrier() system call 1634 Enable the membarrier() system call that allows issuing memory
1753 barriers across all running threads 1635 barriers across all running threads, which can be used to distribute
1754 the cost of user-space memory barri 1636 the cost of user-space memory barriers asymmetrically by transforming
1755 pairs of memory barriers into pairs 1637 pairs of memory barriers into pairs consisting of membarrier() and a
1756 compiler barrier. 1638 compiler barrier.
1757 1639
1758 If unsure, say Y. 1640 If unsure, say Y.
1759 1641
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 1642 config KALLSYMS
1811 bool "Load all symbols for debugging/ 1643 bool "Load all symbols for debugging/ksymoops" if EXPERT
1812 default y 1644 default y
1813 help 1645 help
1814 Say Y here to let the kernel print 1646 Say Y here to let the kernel print out symbolic crash information and
1815 symbolic stack backtraces. This inc 1647 symbolic stack backtraces. This increases the size of the kernel
1816 somewhat, as all symbols have to be 1648 somewhat, as all symbols have to be loaded into the kernel image.
1817 1649
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 1650 config KALLSYMS_ALL
1832 bool "Include all symbols in kallsyms 1651 bool "Include all symbols in kallsyms"
1833 depends on DEBUG_KERNEL && KALLSYMS 1652 depends on DEBUG_KERNEL && KALLSYMS
1834 help 1653 help
1835 Normally kallsyms only contains the 1654 Normally kallsyms only contains the symbols of functions for nicer
1836 OOPS messages and backtraces (i.e., 1655 OOPS messages and backtraces (i.e., symbols from the text and inittext
1837 sections). This is sufficient for m !! 1656 sections). This is sufficient for most cases. And only in very rare
1838 enable kernel live patching, or oth !! 1657 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1839 when a debugger is used) all symbol !! 1658 names of variables from the data sections, etc).
1840 variables from the data sections, e <<
1841 1659
1842 This option makes sure that all sym 1660 This option makes sure that all symbols are loaded into the kernel
1843 image (i.e., symbols from all secti 1661 image (i.e., symbols from all sections) in cost of increased kernel
1844 size (depending on the kernel confi 1662 size (depending on the kernel configuration, it may be 300KiB or
1845 something like this). 1663 something like this).
1846 1664
1847 Say N unless you really need all sy !! 1665 Say N unless you really need all symbols.
1848 1666
1849 config KALLSYMS_ABSOLUTE_PERCPU 1667 config KALLSYMS_ABSOLUTE_PERCPU
1850 bool 1668 bool
1851 depends on KALLSYMS 1669 depends on KALLSYMS
1852 default X86_64 && SMP 1670 default X86_64 && SMP
1853 1671
>> 1672 config KALLSYMS_BASE_RELATIVE
>> 1673 bool
>> 1674 depends on KALLSYMS
>> 1675 default !IA64
>> 1676 help
>> 1677 Instead of emitting them as absolute values in the native word size,
>> 1678 emit the symbol references in the kallsyms table as 32-bit entries,
>> 1679 each containing a relative value in the range [base, base + U32_MAX]
>> 1680 or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either
>> 1681 an absolute value in the range [0, S32_MAX] or a relative value in the
>> 1682 range [base, base + S32_MAX], where base is the lowest relative symbol
>> 1683 address encountered in the image.
>> 1684
>> 1685 On 64-bit builds, this reduces the size of the address table by 50%,
>> 1686 but more importantly, it results in entries whose values are build
>> 1687 time constants, and no relocation pass is required at runtime to fix
>> 1688 up the entries based on the runtime load address of the kernel.
>> 1689
1854 # end of the "standard kernel features (exper 1690 # end of the "standard kernel features (expert users)" menu
1855 1691
>> 1692 # syscall, maps, verifier
>> 1693
>> 1694 config BPF_LSM
>> 1695 bool "LSM Instrumentation with BPF"
>> 1696 depends on BPF_EVENTS
>> 1697 depends on BPF_SYSCALL
>> 1698 depends on SECURITY
>> 1699 depends on BPF_JIT
>> 1700 help
>> 1701 Enables instrumentation of the security hooks with eBPF programs for
>> 1702 implementing dynamic MAC and Audit Policies.
>> 1703
>> 1704 If you are unsure how to answer this question, answer N.
>> 1705
>> 1706 config BPF_SYSCALL
>> 1707 bool "Enable bpf() system call"
>> 1708 select BPF
>> 1709 select IRQ_WORK
>> 1710 select TASKS_TRACE_RCU
>> 1711 default n
>> 1712 help
>> 1713 Enable the bpf() system call that allows to manipulate eBPF
>> 1714 programs and maps via file descriptors.
>> 1715
>> 1716 config ARCH_WANT_DEFAULT_BPF_JIT
>> 1717 bool
>> 1718
>> 1719 config BPF_JIT_ALWAYS_ON
>> 1720 bool "Permanently enable BPF JIT and remove BPF interpreter"
>> 1721 depends on BPF_SYSCALL && HAVE_EBPF_JIT && BPF_JIT
>> 1722 help
>> 1723 Enables BPF JIT and removes BPF interpreter to avoid
>> 1724 speculative execution of BPF instructions by the interpreter
>> 1725
>> 1726 config BPF_JIT_DEFAULT_ON
>> 1727 def_bool ARCH_WANT_DEFAULT_BPF_JIT || BPF_JIT_ALWAYS_ON
>> 1728 depends on HAVE_EBPF_JIT && BPF_JIT
>> 1729
>> 1730 source "kernel/bpf/preload/Kconfig"
>> 1731
>> 1732 config USERFAULTFD
>> 1733 bool "Enable userfaultfd() system call"
>> 1734 depends on MMU
>> 1735 help
>> 1736 Enable the userfaultfd() system call that allows to intercept and
>> 1737 handle page faults in userland.
>> 1738
1856 config ARCH_HAS_MEMBARRIER_CALLBACKS 1739 config ARCH_HAS_MEMBARRIER_CALLBACKS
1857 bool 1740 bool
1858 1741
1859 config ARCH_HAS_MEMBARRIER_SYNC_CORE 1742 config ARCH_HAS_MEMBARRIER_SYNC_CORE
1860 bool 1743 bool
1861 1744
>> 1745 config KCMP
>> 1746 bool "Enable kcmp() system call" if EXPERT
>> 1747 help
>> 1748 Enable the kernel resource comparison system call. It provides
>> 1749 user-space with the ability to compare two processes to see if they
>> 1750 share a common resource, such as a file descriptor or even virtual
>> 1751 memory space.
>> 1752
>> 1753 If unsure, say N.
>> 1754
>> 1755 config RSEQ
>> 1756 bool "Enable rseq() system call" if EXPERT
>> 1757 default y
>> 1758 depends on HAVE_RSEQ
>> 1759 select MEMBARRIER
>> 1760 help
>> 1761 Enable the restartable sequences system call. It provides a
>> 1762 user-space cache for the current CPU number value, which
>> 1763 speeds up getting the current CPU number from user-space,
>> 1764 as well as an ABI to speed up user-space operations on
>> 1765 per-CPU data.
>> 1766
>> 1767 If unsure, say Y.
>> 1768
>> 1769 config DEBUG_RSEQ
>> 1770 default n
>> 1771 bool "Enabled debugging of rseq() system call" if EXPERT
>> 1772 depends on RSEQ && DEBUG_KERNEL
>> 1773 help
>> 1774 Enable extra debugging checks for the rseq system call.
>> 1775
>> 1776 If unsure, say N.
>> 1777
>> 1778 config EMBEDDED
>> 1779 bool "Embedded system"
>> 1780 option allnoconfig_y
>> 1781 select EXPERT
>> 1782 help
>> 1783 This option should be enabled if compiling the kernel for
>> 1784 an embedded system so certain expert options are available
>> 1785 for configuration.
>> 1786
1862 config HAVE_PERF_EVENTS 1787 config HAVE_PERF_EVENTS
1863 bool 1788 bool
1864 help 1789 help
1865 See tools/perf/design.txt for detai 1790 See tools/perf/design.txt for details.
1866 1791
1867 config GUEST_PERF_EVENTS <<
1868 bool <<
1869 depends on HAVE_PERF_EVENTS <<
1870 <<
1871 config PERF_USE_VMALLOC 1792 config PERF_USE_VMALLOC
1872 bool 1793 bool
1873 help 1794 help
1874 See tools/perf/design.txt for detai 1795 See tools/perf/design.txt for details
1875 1796
>> 1797 config PC104
>> 1798 bool "PC/104 support" if EXPERT
>> 1799 help
>> 1800 Expose PC/104 form factor device drivers and options available for
>> 1801 selection and configuration. Enable this option if your target
>> 1802 machine has a PC/104 bus.
>> 1803
1876 menu "Kernel Performance Events And Counters" 1804 menu "Kernel Performance Events And Counters"
1877 1805
1878 config PERF_EVENTS 1806 config PERF_EVENTS
1879 bool "Kernel performance events and c 1807 bool "Kernel performance events and counters"
1880 default y if PROFILING 1808 default y if PROFILING
1881 depends on HAVE_PERF_EVENTS 1809 depends on HAVE_PERF_EVENTS
1882 select IRQ_WORK 1810 select IRQ_WORK
>> 1811 select SRCU
1883 help 1812 help
1884 Enable kernel support for various p 1813 Enable kernel support for various performance events provided
1885 by software and hardware. 1814 by software and hardware.
1886 1815
1887 Software events are supported eithe 1816 Software events are supported either built-in or via the
1888 use of generic tracepoints. 1817 use of generic tracepoints.
1889 1818
1890 Most modern CPUs support performanc 1819 Most modern CPUs support performance events via performance
1891 counter registers. These registers 1820 counter registers. These registers count the number of certain
1892 types of hw events: such as instruc 1821 types of hw events: such as instructions executed, cachemisses
1893 suffered, or branches mis-predicted 1822 suffered, or branches mis-predicted - without slowing down the
1894 kernel or applications. These regis 1823 kernel or applications. These registers can also trigger interrupts
1895 when a threshold number of events h 1824 when a threshold number of events have passed - and can thus be
1896 used to profile the code that runs 1825 used to profile the code that runs on that CPU.
1897 1826
1898 The Linux Performance Event subsyst 1827 The Linux Performance Event subsystem provides an abstraction of
1899 these software and hardware event c 1828 these software and hardware event capabilities, available via a
1900 system call and used by the "perf" 1829 system call and used by the "perf" utility in tools/perf/. It
1901 provides per task and per CPU count 1830 provides per task and per CPU counters, and it provides event
1902 capabilities on top of those. 1831 capabilities on top of those.
1903 1832
1904 Say Y if unsure. 1833 Say Y if unsure.
1905 1834
1906 config DEBUG_PERF_USE_VMALLOC 1835 config DEBUG_PERF_USE_VMALLOC
1907 default n 1836 default n
1908 bool "Debug: use vmalloc to back perf 1837 bool "Debug: use vmalloc to back perf mmap() buffers"
1909 depends on PERF_EVENTS && DEBUG_KERNE 1838 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
1910 select PERF_USE_VMALLOC 1839 select PERF_USE_VMALLOC
1911 help 1840 help
1912 Use vmalloc memory to back perf mma 1841 Use vmalloc memory to back perf mmap() buffers.
1913 1842
1914 Mostly useful for debugging the vma 1843 Mostly useful for debugging the vmalloc code on platforms
1915 that don't require it. 1844 that don't require it.
1916 1845
1917 Say N if unsure. 1846 Say N if unsure.
1918 1847
1919 endmenu 1848 endmenu
1920 1849
>> 1850 config VM_EVENT_COUNTERS
>> 1851 default y
>> 1852 bool "Enable VM event counters for /proc/vmstat" if EXPERT
>> 1853 help
>> 1854 VM event counters are needed for event counts to be shown.
>> 1855 This option allows the disabling of the VM event counters
>> 1856 on EXPERT systems. /proc/vmstat will only show page counts
>> 1857 if VM event counters are disabled.
>> 1858
>> 1859 config SLUB_DEBUG
>> 1860 default y
>> 1861 bool "Enable SLUB debugging support" if EXPERT
>> 1862 depends on SLUB && SYSFS
>> 1863 help
>> 1864 SLUB has extensive debug support features. Disabling these can
>> 1865 result in significant savings in code size. This also disables
>> 1866 SLUB sysfs support. /sys/slab will not exist and there will be
>> 1867 no support for cache validation etc.
>> 1868
>> 1869 config COMPAT_BRK
>> 1870 bool "Disable heap randomization"
>> 1871 default y
>> 1872 help
>> 1873 Randomizing heap placement makes heap exploits harder, but it
>> 1874 also breaks ancient binaries (including anything libc5 based).
>> 1875 This option changes the bootup default to heap randomization
>> 1876 disabled, and can be overridden at runtime by setting
>> 1877 /proc/sys/kernel/randomize_va_space to 2.
>> 1878
>> 1879 On non-ancient distros (post-2000 ones) N is usually a safe choice.
>> 1880
>> 1881 choice
>> 1882 prompt "Choose SLAB allocator"
>> 1883 default SLUB
>> 1884 help
>> 1885 This option allows to select a slab allocator.
>> 1886
>> 1887 config SLAB
>> 1888 bool "SLAB"
>> 1889 select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 1890 help
>> 1891 The regular slab allocator that is established and known to work
>> 1892 well in all environments. It organizes cache hot objects in
>> 1893 per cpu and per node queues.
>> 1894
>> 1895 config SLUB
>> 1896 bool "SLUB (Unqueued Allocator)"
>> 1897 select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 1898 help
>> 1899 SLUB is a slab allocator that minimizes cache line usage
>> 1900 instead of managing queues of cached objects (SLAB approach).
>> 1901 Per cpu caching is realized using slabs of objects instead
>> 1902 of queues of objects. SLUB can use memory efficiently
>> 1903 and has enhanced diagnostics. SLUB is the default choice for
>> 1904 a slab allocator.
>> 1905
>> 1906 config SLOB
>> 1907 depends on EXPERT
>> 1908 bool "SLOB (Simple Allocator)"
>> 1909 help
>> 1910 SLOB replaces the stock allocator with a drastically simpler
>> 1911 allocator. SLOB is generally more space efficient but
>> 1912 does not perform as well on large systems.
>> 1913
>> 1914 endchoice
>> 1915
>> 1916 config SLAB_MERGE_DEFAULT
>> 1917 bool "Allow slab caches to be merged"
>> 1918 default y
>> 1919 help
>> 1920 For reduced kernel memory fragmentation, slab caches can be
>> 1921 merged when they share the same size and other characteristics.
>> 1922 This carries a risk of kernel heap overflows being able to
>> 1923 overwrite objects from merged caches (and more easily control
>> 1924 cache layout), which makes such heap attacks easier to exploit
>> 1925 by attackers. By keeping caches unmerged, these kinds of exploits
>> 1926 can usually only damage objects in the same cache. To disable
>> 1927 merging at runtime, "slab_nomerge" can be passed on the kernel
>> 1928 command line.
>> 1929
>> 1930 config SLAB_FREELIST_RANDOM
>> 1931 bool "Randomize slab freelist"
>> 1932 depends on SLAB || SLUB
>> 1933 help
>> 1934 Randomizes the freelist order used on creating new pages. This
>> 1935 security feature reduces the predictability of the kernel slab
>> 1936 allocator against heap overflows.
>> 1937
>> 1938 config SLAB_FREELIST_HARDENED
>> 1939 bool "Harden slab freelist metadata"
>> 1940 depends on SLAB || SLUB
>> 1941 help
>> 1942 Many kernel heap attacks try to target slab cache metadata and
>> 1943 other infrastructure. This options makes minor performance
>> 1944 sacrifices to harden the kernel slab allocator against common
>> 1945 freelist exploit methods. Some slab implementations have more
>> 1946 sanity-checking than others. This option is most effective with
>> 1947 CONFIG_SLUB.
>> 1948
>> 1949 config SHUFFLE_PAGE_ALLOCATOR
>> 1950 bool "Page allocator randomization"
>> 1951 default SLAB_FREELIST_RANDOM && ACPI_NUMA
>> 1952 help
>> 1953 Randomization of the page allocator improves the average
>> 1954 utilization of a direct-mapped memory-side-cache. See section
>> 1955 5.2.27 Heterogeneous Memory Attribute Table (HMAT) in the ACPI
>> 1956 6.2a specification for an example of how a platform advertises
>> 1957 the presence of a memory-side-cache. There are also incidental
>> 1958 security benefits as it reduces the predictability of page
>> 1959 allocations to compliment SLAB_FREELIST_RANDOM, but the
>> 1960 default granularity of shuffling on the "MAX_ORDER - 1" i.e,
>> 1961 10th order of pages is selected based on cache utilization
>> 1962 benefits on x86.
>> 1963
>> 1964 While the randomization improves cache utilization it may
>> 1965 negatively impact workloads on platforms without a cache. For
>> 1966 this reason, by default, the randomization is enabled only
>> 1967 after runtime detection of a direct-mapped memory-side-cache.
>> 1968 Otherwise, the randomization may be force enabled with the
>> 1969 'page_alloc.shuffle' kernel command line parameter.
>> 1970
>> 1971 Say Y if unsure.
>> 1972
>> 1973 config SLUB_CPU_PARTIAL
>> 1974 default y
>> 1975 depends on SLUB && SMP
>> 1976 bool "SLUB per cpu partial cache"
>> 1977 help
>> 1978 Per cpu partial caches accelerate objects allocation and freeing
>> 1979 that is local to a processor at the price of more indeterminism
>> 1980 in the latency of the free. On overflow these caches will be cleared
>> 1981 which requires the taking of locks that may cause latency spikes.
>> 1982 Typically one would choose no for a realtime system.
>> 1983
>> 1984 config MMAP_ALLOW_UNINITIALIZED
>> 1985 bool "Allow mmapped anonymous memory to be uninitialized"
>> 1986 depends on EXPERT && !MMU
>> 1987 default n
>> 1988 help
>> 1989 Normally, and according to the Linux spec, anonymous memory obtained
>> 1990 from mmap() has its contents cleared before it is passed to
>> 1991 userspace. Enabling this config option allows you to request that
>> 1992 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
>> 1993 providing a huge performance boost. If this option is not enabled,
>> 1994 then the flag will be ignored.
>> 1995
>> 1996 This is taken advantage of by uClibc's malloc(), and also by
>> 1997 ELF-FDPIC binfmt's brk and stack allocator.
>> 1998
>> 1999 Because of the obvious security issues, this option should only be
>> 2000 enabled on embedded devices where you control what is run in
>> 2001 userspace. Since that isn't generally a problem on no-MMU systems,
>> 2002 it is normally safe to say Y here.
>> 2003
>> 2004 See Documentation/admin-guide/mm/nommu-mmap.rst for more information.
>> 2005
1921 config SYSTEM_DATA_VERIFICATION 2006 config SYSTEM_DATA_VERIFICATION
1922 def_bool n 2007 def_bool n
1923 select SYSTEM_TRUSTED_KEYRING 2008 select SYSTEM_TRUSTED_KEYRING
1924 select KEYS 2009 select KEYS
1925 select CRYPTO 2010 select CRYPTO
1926 select CRYPTO_RSA 2011 select CRYPTO_RSA
1927 select ASYMMETRIC_KEY_TYPE 2012 select ASYMMETRIC_KEY_TYPE
1928 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 2013 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1929 select ASN1 2014 select ASN1
1930 select OID_REGISTRY 2015 select OID_REGISTRY
1931 select X509_CERTIFICATE_PARSER 2016 select X509_CERTIFICATE_PARSER
1932 select PKCS7_MESSAGE_PARSER 2017 select PKCS7_MESSAGE_PARSER
1933 help 2018 help
1934 Provide PKCS#7 message verification 2019 Provide PKCS#7 message verification using the contents of the system
1935 trusted keyring to provide public k 2020 trusted keyring to provide public keys. This then can be used for
1936 module verification, kexec image ve 2021 module verification, kexec image verification and firmware blob
1937 verification. 2022 verification.
1938 2023
1939 config PROFILING 2024 config PROFILING
1940 bool "Profiling support" 2025 bool "Profiling support"
1941 help 2026 help
1942 Say Y here to enable the extended p 2027 Say Y here to enable the extended profiling support mechanisms used
1943 by profilers. 2028 by profilers.
1944 2029
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 # 2030 #
1987 # Place an empty function call at each tracep 2031 # Place an empty function call at each tracepoint site. Can be
1988 # dynamically changed for a probe function. 2032 # dynamically changed for a probe function.
1989 # 2033 #
1990 config TRACEPOINTS 2034 config TRACEPOINTS
1991 bool 2035 bool
1992 2036
1993 source "kernel/Kconfig.kexec" <<
1994 <<
1995 endmenu # General setup 2037 endmenu # General setup
1996 2038
1997 source "arch/Kconfig" 2039 source "arch/Kconfig"
1998 2040
1999 config RT_MUTEXES 2041 config RT_MUTEXES
2000 bool 2042 bool
2001 default y if PREEMPT_RT !! 2043
>> 2044 config BASE_SMALL
>> 2045 int
>> 2046 default 0 if BASE_FULL
>> 2047 default 1 if !BASE_FULL
2002 2048
2003 config MODULE_SIG_FORMAT 2049 config MODULE_SIG_FORMAT
2004 def_bool n 2050 def_bool n
2005 select SYSTEM_DATA_VERIFICATION 2051 select SYSTEM_DATA_VERIFICATION
2006 2052
2007 source "kernel/module/Kconfig" !! 2053 menuconfig MODULES
>> 2054 bool "Enable loadable module support"
>> 2055 option modules
>> 2056 help
>> 2057 Kernel modules are small pieces of compiled code which can
>> 2058 be inserted in the running kernel, rather than being
>> 2059 permanently built into the kernel. You use the "modprobe"
>> 2060 tool to add (and sometimes remove) them. If you say Y here,
>> 2061 many parts of the kernel can be built as modules (by
>> 2062 answering M instead of Y where indicated): this is most
>> 2063 useful for infrequently used options which are not required
>> 2064 for booting. For more information, see the man pages for
>> 2065 modprobe, lsmod, modinfo, insmod and rmmod.
>> 2066
>> 2067 If you say Y here, you will need to run "make
>> 2068 modules_install" to put the modules under /lib/modules/
>> 2069 where modprobe can find them (you may need to be root to do
>> 2070 this).
>> 2071
>> 2072 If unsure, say Y.
>> 2073
>> 2074 if MODULES
>> 2075
>> 2076 config MODULE_FORCE_LOAD
>> 2077 bool "Forced module loading"
>> 2078 default n
>> 2079 help
>> 2080 Allow loading of modules without version information (ie. modprobe
>> 2081 --force). Forced module loading sets the 'F' (forced) taint flag and
>> 2082 is usually a really bad idea.
>> 2083
>> 2084 config MODULE_UNLOAD
>> 2085 bool "Module unloading"
>> 2086 help
>> 2087 Without this option you will not be able to unload any
>> 2088 modules (note that some modules may not be unloadable
>> 2089 anyway), which makes your kernel smaller, faster
>> 2090 and simpler. If unsure, say Y.
>> 2091
>> 2092 config MODULE_FORCE_UNLOAD
>> 2093 bool "Forced module unloading"
>> 2094 depends on MODULE_UNLOAD
>> 2095 help
>> 2096 This option allows you to force a module to unload, even if the
>> 2097 kernel believes it is unsafe: the kernel will remove the module
>> 2098 without waiting for anyone to stop using it (using the -f option to
>> 2099 rmmod). This is mainly for kernel developers and desperate users.
>> 2100 If unsure, say N.
>> 2101
>> 2102 config MODVERSIONS
>> 2103 bool "Module versioning support"
>> 2104 help
>> 2105 Usually, you have to use modules compiled with your kernel.
>> 2106 Saying Y here makes it sometimes possible to use modules
>> 2107 compiled for different kernels, by adding enough information
>> 2108 to the modules to (hopefully) spot any changes which would
>> 2109 make them incompatible with the kernel you are running. If
>> 2110 unsure, say N.
>> 2111
>> 2112 config ASM_MODVERSIONS
>> 2113 bool
>> 2114 default HAVE_ASM_MODVERSIONS && MODVERSIONS
>> 2115 help
>> 2116 This enables module versioning for exported symbols also from
>> 2117 assembly. This can be enabled only when the target architecture
>> 2118 supports it.
>> 2119
>> 2120 config MODULE_REL_CRCS
>> 2121 bool
>> 2122 depends on MODVERSIONS
>> 2123
>> 2124 config MODULE_SRCVERSION_ALL
>> 2125 bool "Source checksum for all modules"
>> 2126 help
>> 2127 Modules which contain a MODULE_VERSION get an extra "srcversion"
>> 2128 field inserted into their modinfo section, which contains a
>> 2129 sum of the source files which made it. This helps maintainers
>> 2130 see exactly which source was used to build a module (since
>> 2131 others sometimes change the module source without updating
>> 2132 the version). With this option, such a "srcversion" field
>> 2133 will be created for all modules. If unsure, say N.
>> 2134
>> 2135 config MODULE_SIG
>> 2136 bool "Module signature verification"
>> 2137 select MODULE_SIG_FORMAT
>> 2138 help
>> 2139 Check modules for valid signatures upon load: the signature
>> 2140 is simply appended to the module. For more information see
>> 2141 <file:Documentation/admin-guide/module-signing.rst>.
>> 2142
>> 2143 Note that this option adds the OpenSSL development packages as a
>> 2144 kernel build dependency so that the signing tool can use its crypto
>> 2145 library.
>> 2146
>> 2147 You should enable this option if you wish to use either
>> 2148 CONFIG_SECURITY_LOCKDOWN_LSM or lockdown functionality imposed via
>> 2149 another LSM - otherwise unsigned modules will be loadable regardless
>> 2150 of the lockdown policy.
>> 2151
>> 2152 !!!WARNING!!! If you enable this option, you MUST make sure that the
>> 2153 module DOES NOT get stripped after being signed. This includes the
>> 2154 debuginfo strip done by some packagers (such as rpmbuild) and
>> 2155 inclusion into an initramfs that wants the module size reduced.
>> 2156
>> 2157 config MODULE_SIG_FORCE
>> 2158 bool "Require modules to be validly signed"
>> 2159 depends on MODULE_SIG
>> 2160 help
>> 2161 Reject unsigned modules or signed modules for which we don't have a
>> 2162 key. Without this, such modules will simply taint the kernel.
>> 2163
>> 2164 config MODULE_SIG_ALL
>> 2165 bool "Automatically sign all modules"
>> 2166 default y
>> 2167 depends on MODULE_SIG
>> 2168 help
>> 2169 Sign all modules during make modules_install. Without this option,
>> 2170 modules must be signed manually, using the scripts/sign-file tool.
>> 2171
>> 2172 comment "Do not forget to sign required modules with scripts/sign-file"
>> 2173 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
>> 2174
>> 2175 choice
>> 2176 prompt "Which hash algorithm should modules be signed with?"
>> 2177 depends on MODULE_SIG
>> 2178 help
>> 2179 This determines which sort of hashing algorithm will be used during
>> 2180 signature generation. This algorithm _must_ be built into the kernel
>> 2181 directly so that signature verification can take place. It is not
>> 2182 possible to load a signed module containing the algorithm to check
>> 2183 the signature on that module.
>> 2184
>> 2185 config MODULE_SIG_SHA1
>> 2186 bool "Sign modules with SHA-1"
>> 2187 select CRYPTO_SHA1
>> 2188
>> 2189 config MODULE_SIG_SHA224
>> 2190 bool "Sign modules with SHA-224"
>> 2191 select CRYPTO_SHA256
>> 2192
>> 2193 config MODULE_SIG_SHA256
>> 2194 bool "Sign modules with SHA-256"
>> 2195 select CRYPTO_SHA256
>> 2196
>> 2197 config MODULE_SIG_SHA384
>> 2198 bool "Sign modules with SHA-384"
>> 2199 select CRYPTO_SHA512
>> 2200
>> 2201 config MODULE_SIG_SHA512
>> 2202 bool "Sign modules with SHA-512"
>> 2203 select CRYPTO_SHA512
>> 2204
>> 2205 endchoice
>> 2206
>> 2207 config MODULE_SIG_HASH
>> 2208 string
>> 2209 depends on MODULE_SIG
>> 2210 default "sha1" if MODULE_SIG_SHA1
>> 2211 default "sha224" if MODULE_SIG_SHA224
>> 2212 default "sha256" if MODULE_SIG_SHA256
>> 2213 default "sha384" if MODULE_SIG_SHA384
>> 2214 default "sha512" if MODULE_SIG_SHA512
>> 2215
>> 2216 config MODULE_COMPRESS
>> 2217 bool "Compress modules on installation"
>> 2218 help
>> 2219
>> 2220 Compresses kernel modules when 'make modules_install' is run; gzip or
>> 2221 xz depending on "Compression algorithm" below.
>> 2222
>> 2223 module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
>> 2224
>> 2225 Out-of-tree kernel modules installed using Kbuild will also be
>> 2226 compressed upon installation.
>> 2227
>> 2228 Note: for modules inside an initrd or initramfs, it's more efficient
>> 2229 to compress the whole initrd or initramfs instead.
>> 2230
>> 2231 Note: This is fully compatible with signed modules.
>> 2232
>> 2233 If in doubt, say N.
>> 2234
>> 2235 choice
>> 2236 prompt "Compression algorithm"
>> 2237 depends on MODULE_COMPRESS
>> 2238 default MODULE_COMPRESS_GZIP
>> 2239 help
>> 2240 This determines which sort of compression will be used during
>> 2241 'make modules_install'.
>> 2242
>> 2243 GZIP (default) and XZ are supported.
>> 2244
>> 2245 config MODULE_COMPRESS_GZIP
>> 2246 bool "GZIP"
>> 2247
>> 2248 config MODULE_COMPRESS_XZ
>> 2249 bool "XZ"
>> 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 TRIM_UNUSED_KSYMS
>> 2267 bool "Trim unused exported kernel symbols" if EXPERT
>> 2268 depends on !COMPILE_TEST
>> 2269 help
>> 2270 The kernel and some modules make many symbols available for
>> 2271 other modules to use via EXPORT_SYMBOL() and variants. Depending
>> 2272 on the set of modules being selected in your kernel configuration,
>> 2273 many of those exported symbols might never be used.
>> 2274
>> 2275 This option allows for unused exported symbols to be dropped from
>> 2276 the build. In turn, this provides the compiler more opportunities
>> 2277 (especially when using LTO) for optimizing the code and reducing
>> 2278 binary size. This might have some security advantages as well.
>> 2279
>> 2280 If unsure, or if you need to build out-of-tree modules, say N.
>> 2281
>> 2282 config UNUSED_KSYMS_WHITELIST
>> 2283 string "Whitelist of symbols to keep in ksymtab"
>> 2284 depends on TRIM_UNUSED_KSYMS
>> 2285 help
>> 2286 By default, all unused exported symbols will be un-exported from the
>> 2287 build when TRIM_UNUSED_KSYMS is selected.
>> 2288
>> 2289 UNUSED_KSYMS_WHITELIST allows to whitelist symbols that must be kept
>> 2290 exported at all times, even in absence of in-tree users. The value to
>> 2291 set here is the path to a text file containing the list of symbols,
>> 2292 one per line. The path can be absolute, or relative to the kernel
>> 2293 source tree.
>> 2294
>> 2295 endif # MODULES
>> 2296
>> 2297 config MODULES_TREE_LOOKUP
>> 2298 def_bool y
>> 2299 depends on PERF_EVENTS || TRACING
2008 2300
2009 config INIT_ALL_POSSIBLE 2301 config INIT_ALL_POSSIBLE
2010 bool 2302 bool
2011 help 2303 help
2012 Back when each arch used to define 2304 Back when each arch used to define their own cpu_online_mask and
2013 cpu_possible_mask, some of them cho 2305 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
2014 with all 1s, and others with all 0s 2306 with all 1s, and others with all 0s. When they were centralised,
2015 it was better to provide this optio 2307 it was better to provide this option than to break all the archs
2016 and have several arch maintainers p 2308 and have several arch maintainers pursuing me down dark alleys.
2017 2309
2018 source "block/Kconfig" 2310 source "block/Kconfig"
2019 2311
2020 config PREEMPT_NOTIFIERS 2312 config PREEMPT_NOTIFIERS
2021 bool 2313 bool
2022 2314
2023 config PADATA 2315 config PADATA
2024 depends on SMP 2316 depends on SMP
2025 bool 2317 bool
2026 2318
2027 config ASN1 2319 config ASN1
2028 tristate 2320 tristate
2029 help 2321 help
2030 Build a simple ASN.1 grammar compil 2322 Build a simple ASN.1 grammar compiler that produces a bytecode output
2031 that can be interpreted by the ASN. 2323 that can be interpreted by the ASN.1 stream decoder and used to
2032 inform it as to what tags are to be 2324 inform it as to what tags are to be expected in a stream and what
2033 functions to call on what tags. 2325 functions to call on what tags.
2034 2326
2035 source "kernel/Kconfig.locks" 2327 source "kernel/Kconfig.locks"
2036 2328
2037 config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 2329 config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
2038 bool <<
2039 <<
2040 config ARCH_HAS_PREPARE_SYNC_CORE_CMD <<
2041 bool 2330 bool
2042 2331
2043 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2332 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
2044 bool 2333 bool
2045 2334
2046 # It may be useful for an architecture to ove 2335 # It may be useful for an architecture to override the definitions of the
2047 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() ma 2336 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h>
2048 # and the COMPAT_ variants in <linux/compat.h 2337 # and the COMPAT_ variants in <linux/compat.h>, in particular to use a
2049 # different calling convention for syscalls. 2338 # different calling convention for syscalls. They can also override the
2050 # macros for not-implemented syscalls in kern 2339 # macros for not-implemented syscalls in kernel/sys_ni.c and
2051 # kernel/time/posix-stubs.c. All these overri 2340 # kernel/time/posix-stubs.c. All these overrides need to be available in
2052 # <asm/syscall_wrapper.h>. 2341 # <asm/syscall_wrapper.h>.
2053 config ARCH_HAS_SYSCALL_WRAPPER 2342 config ARCH_HAS_SYSCALL_WRAPPER
2054 def_bool n 2343 def_bool n
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