1 # SPDX-License-Identifier: GPL-2.0-only !! 1 config DEFCONFIG_LIST
2 config CC_VERSION_TEXT <<
3 string 2 string
4 default "$(CC_VERSION_TEXT)" !! 3 depends on !UML
5 help !! 4 option defconfig_list
6 This is used in unclear ways: !! 5 default "/lib/modules/$(shell,uname -r)/.config"
7 !! 6 default "/etc/kernel-config"
8 - Re-run Kconfig when the compiler i !! 7 default "/boot/config-$(shell,uname -r)"
9 The 'default' property references !! 8 default ARCH_DEFCONFIG
10 CC_VERSION_TEXT so it is recorded !! 9 default "arch/$(ARCH)/defconfig"
11 When the compiler is updated, Kcon <<
12 <<
13 - Ensure full rebuild when the compi <<
14 include/linux/compiler-version.h c <<
15 line so fixdep adds include/config <<
16 auto-generated dependency. When th <<
17 will touch it and then every file <<
18 10
19 config CC_IS_GCC 11 config CC_IS_GCC
20 def_bool $(success,test "$(cc-name)" = !! 12 def_bool $(success,$(CC) --version | head -n 1 | grep -q gcc)
21 13
22 config GCC_VERSION 14 config GCC_VERSION
23 int 15 int
24 default $(cc-version) if CC_IS_GCC !! 16 default $(shell,$(srctree)/scripts/gcc-version.sh $(CC)) if CC_IS_GCC
25 default 0 17 default 0
26 18
27 config CC_IS_CLANG 19 config CC_IS_CLANG
28 def_bool $(success,test "$(cc-name)" = !! 20 def_bool $(success,$(CC) --version | head -n 1 | grep -q clang)
29 21
30 config CLANG_VERSION 22 config CLANG_VERSION
31 int 23 int
32 default $(cc-version) if CC_IS_CLANG !! 24 default $(shell,$(srctree)/scripts/clang-version.sh $(CC))
33 default 0 <<
34 <<
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 <<
48 def_bool $(success,test "$(ld-name)" = <<
49 <<
50 config LD_VERSION <<
51 int <<
52 default $(ld-version) if LD_IS_BFD <<
53 default 0 <<
54 <<
55 config LD_IS_LLD <<
56 def_bool $(success,test "$(ld-name)" = <<
57 <<
58 config LLD_VERSION <<
59 int <<
60 default $(ld-version) if LD_IS_LLD <<
61 default 0 <<
62 25
63 config RUSTC_VERSION !! 26 config CC_HAS_ASM_GOTO
64 int !! 27 def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC))
65 default $(rustc-version) <<
66 help <<
67 It does not depend on `RUST` since t <<
68 in a `depends on`. <<
69 28
70 config RUST_IS_AVAILABLE !! 29 config CC_HAS_WARN_MAYBE_UNINITIALIZED
71 def_bool $(success,$(srctree)/scripts/ !! 30 def_bool $(cc-option,-Wmaybe-uninitialized)
72 help 31 help
73 This shows whether a suitable Rust t !! 32 GCC >= 4.7 supports this option.
74 <<
75 Please see Documentation/rust/quick- <<
76 to satisfy the build requirements of <<
77 33
78 In particular, the Makefile target ' !! 34 config CC_DISABLE_WARN_MAYBE_UNINITIALIZED
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 <<
86 bool 35 bool
87 default $(success,$(srctree)/scripts/c !! 36 depends on CC_HAS_WARN_MAYBE_UNINITIALIZED
88 default $(success,$(srctree)/scripts/c !! 37 default CC_IS_GCC && GCC_VERSION < 40900 # unreliable for GCC < 4.9
89 !! 38 help
90 config CC_CAN_LINK_STATIC !! 39 GCC's -Wmaybe-uninitialized is not reliable by definition.
91 bool !! 40 Lots of false positive warnings are produced in some cases.
92 default $(success,$(srctree)/scripts/c <<
93 default $(success,$(srctree)/scripts/c <<
94 <<
95 # Fixed in GCC 14, 13.3, 12.4 and 11.5 <<
96 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id <<
97 config GCC_ASM_GOTO_OUTPUT_BROKEN <<
98 bool <<
99 depends on CC_IS_GCC <<
100 default y if GCC_VERSION < 110500 <<
101 default y if GCC_VERSION >= 120000 && <<
102 default y if GCC_VERSION >= 130000 && <<
103 <<
104 config CC_HAS_ASM_GOTO_OUTPUT <<
105 def_bool y <<
106 depends on !GCC_ASM_GOTO_OUTPUT_BROKEN <<
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 <<
114 config TOOLS_SUPPORT_RELR <<
115 def_bool $(success,env "CC=$(CC)" "LD= <<
116 <<
117 config CC_HAS_ASM_INLINE <<
118 def_bool $(success,echo 'void foo(void <<
119 <<
120 config CC_HAS_NO_PROFILE_FN_ATTR <<
121 def_bool $(success,echo '__attribute__ <<
122 41
123 config PAHOLE_VERSION !! 42 If this option is enabled, -Wno-maybe-uninitialzed is passed
124 int !! 43 to the compiler to suppress maybe-uninitialized warnings.
125 default $(shell,$(srctree)/scripts/pah <<
126 44
127 config CONSTRUCTORS 45 config CONSTRUCTORS
128 bool 46 bool
>> 47 depends on !UML
129 48
130 config IRQ_WORK 49 config IRQ_WORK
131 def_bool y if SMP !! 50 bool
132 51
133 config BUILDTIME_TABLE_SORT !! 52 config BUILDTIME_EXTABLE_SORT
134 bool 53 bool
135 54
136 config THREAD_INFO_IN_TASK 55 config THREAD_INFO_IN_TASK
137 bool 56 bool
138 help 57 help
139 Select this to move thread_info off 58 Select this to move thread_info off the stack into task_struct. To
140 make this work, an arch will need to 59 make this work, an arch will need to remove all thread_info fields
141 except flags and fix any runtime bug 60 except flags and fix any runtime bugs.
142 61
143 One subtle change that will be neede 62 One subtle change that will be needed is to use try_get_task_stack()
144 and put_task_stack() in save_thread_ 63 and put_task_stack() in save_thread_stack_tsk() and get_wchan().
145 64
146 menu "General setup" 65 menu "General setup"
147 66
148 config BROKEN 67 config BROKEN
149 bool 68 bool
150 69
151 config BROKEN_ON_SMP 70 config BROKEN_ON_SMP
152 bool 71 bool
153 depends on BROKEN || !SMP 72 depends on BROKEN || !SMP
154 default y 73 default y
155 74
156 config INIT_ENV_ARG_LIMIT 75 config INIT_ENV_ARG_LIMIT
157 int 76 int
158 default 32 if !UML 77 default 32 if !UML
159 default 128 if UML 78 default 128 if UML
160 help 79 help
161 Maximum of each of the number of arg 80 Maximum of each of the number of arguments and environment
162 variables passed to init from the ke 81 variables passed to init from the kernel command line.
163 82
164 config COMPILE_TEST 83 config COMPILE_TEST
165 bool "Compile also drivers which will 84 bool "Compile also drivers which will not load"
166 depends on HAS_IOMEM !! 85 depends on !UML
>> 86 default n
167 help 87 help
168 Some drivers can be compiled on a di 88 Some drivers can be compiled on a different platform than they are
169 intended to be run on. Despite they 89 intended to be run on. Despite they cannot be loaded there (or even
170 when they load they cannot be used d 90 when they load they cannot be used due to missing HW support),
171 developers still, opposing to distri 91 developers still, opposing to distributors, might want to build such
172 drivers to compile-test them. 92 drivers to compile-test them.
173 93
174 If you are a developer and want to b 94 If you are a developer and want to build everything available, say Y
175 here. If you are a user/distributor, 95 here. If you are a user/distributor, say N here to exclude useless
176 drivers to be distributed. 96 drivers to be distributed.
177 97
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 <<
196 bool "Compile test UAPI headers" <<
197 depends on HEADERS_INSTALL && CC_CAN_L <<
198 help <<
199 Compile test headers exported to use <<
200 self-contained, i.e. compilable as s <<
201 <<
202 If you are a developer or tester and <<
203 headers are self-contained, say Y he <<
204 <<
205 config LOCALVERSION 98 config LOCALVERSION
206 string "Local version - append to kern 99 string "Local version - append to kernel release"
207 help 100 help
208 Append an extra string to the end of 101 Append an extra string to the end of your kernel version.
209 This will show up when you type unam 102 This will show up when you type uname, for example.
210 The string you set here will be appe 103 The string you set here will be appended after the contents of
211 any files with a filename matching l 104 any files with a filename matching localversion* in your
212 object and source tree, in that orde 105 object and source tree, in that order. Your total string can
213 be a maximum of 64 characters. 106 be a maximum of 64 characters.
214 107
215 config LOCALVERSION_AUTO 108 config LOCALVERSION_AUTO
216 bool "Automatically append version inf 109 bool "Automatically append version information to the version string"
217 default y 110 default y
218 depends on !COMPILE_TEST 111 depends on !COMPILE_TEST
219 help 112 help
220 This will try to automatically deter 113 This will try to automatically determine if the current tree is a
221 release tree by looking for git tags 114 release tree by looking for git tags that belong to the current
222 top of tree revision. 115 top of tree revision.
223 116
224 A string of the format -gxxxxxxxx wi 117 A string of the format -gxxxxxxxx will be added to the localversion
225 if a git-based tree is found. The s 118 if a git-based tree is found. The string generated by this will be
226 appended after any matching localver 119 appended after any matching localversion* files, and after the value
227 set in CONFIG_LOCALVERSION. 120 set in CONFIG_LOCALVERSION.
228 121
229 (The actual string used here is the !! 122 (The actual string used here is the first eight characters produced
230 by running the command: 123 by running the command:
231 124
232 $ git rev-parse --verify HEAD 125 $ git rev-parse --verify HEAD
233 126
234 which is done within the script "scr 127 which is done within the script "scripts/setlocalversion".)
235 128
236 config BUILD_SALT 129 config BUILD_SALT
237 string "Build ID Salt" !! 130 string "Build ID Salt"
238 default "" !! 131 default ""
239 help !! 132 help
240 The build ID is used to link binarie !! 133 The build ID is used to link binaries and their debug info. Setting
241 this option will use the value in th !! 134 this option will use the value in the calculation of the build id.
242 This is mostly useful for distributi !! 135 This is mostly useful for distributions which want to ensure the
243 build is unique between builds. It's !! 136 build is unique between builds. It's safe to leave the default.
244 137
245 config HAVE_KERNEL_GZIP 138 config HAVE_KERNEL_GZIP
246 bool 139 bool
247 140
248 config HAVE_KERNEL_BZIP2 141 config HAVE_KERNEL_BZIP2
249 bool 142 bool
250 143
251 config HAVE_KERNEL_LZMA 144 config HAVE_KERNEL_LZMA
252 bool 145 bool
253 146
254 config HAVE_KERNEL_XZ 147 config HAVE_KERNEL_XZ
255 bool 148 bool
256 149
257 config HAVE_KERNEL_LZO 150 config HAVE_KERNEL_LZO
258 bool 151 bool
259 152
260 config HAVE_KERNEL_LZ4 153 config HAVE_KERNEL_LZ4
261 bool 154 bool
262 155
263 config HAVE_KERNEL_ZSTD <<
264 bool <<
265 <<
266 config HAVE_KERNEL_UNCOMPRESSED 156 config HAVE_KERNEL_UNCOMPRESSED
267 bool 157 bool
268 158
269 choice 159 choice
270 prompt "Kernel compression mode" 160 prompt "Kernel compression mode"
271 default KERNEL_GZIP 161 default KERNEL_GZIP
272 depends on HAVE_KERNEL_GZIP || HAVE_KE !! 162 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 || HAVE_KERNEL_UNCOMPRESSED
273 help 163 help
274 The linux kernel is a kind of self-e 164 The linux kernel is a kind of self-extracting executable.
275 Several compression algorithms are a 165 Several compression algorithms are available, which differ
276 in efficiency, compression and decom 166 in efficiency, compression and decompression speed.
277 Compression speed is only relevant w 167 Compression speed is only relevant when building a kernel.
278 Decompression speed is relevant at e 168 Decompression speed is relevant at each boot.
279 169
280 If you have any problems with bzip2 170 If you have any problems with bzip2 or lzma compressed
281 kernels, mail me (Alain Knaff) <alain 171 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
282 version of this functionality (bzip2 172 version of this functionality (bzip2 only), for 2.4, was
283 supplied by Christian Ludwig) 173 supplied by Christian Ludwig)
284 174
285 High compression options are mostly 175 High compression options are mostly useful for users, who
286 are low on disk space (embedded syst 176 are low on disk space (embedded systems), but for whom ram
287 size matters less. 177 size matters less.
288 178
289 If in doubt, select 'gzip' 179 If in doubt, select 'gzip'
290 180
291 config KERNEL_GZIP 181 config KERNEL_GZIP
292 bool "Gzip" 182 bool "Gzip"
293 depends on HAVE_KERNEL_GZIP 183 depends on HAVE_KERNEL_GZIP
294 help 184 help
295 The old and tried gzip compression. 185 The old and tried gzip compression. It provides a good balance
296 between compression ratio and decomp 186 between compression ratio and decompression speed.
297 187
298 config KERNEL_BZIP2 188 config KERNEL_BZIP2
299 bool "Bzip2" 189 bool "Bzip2"
300 depends on HAVE_KERNEL_BZIP2 190 depends on HAVE_KERNEL_BZIP2
301 help 191 help
302 Its compression ratio and speed is i 192 Its compression ratio and speed is intermediate.
303 Decompression speed is slowest among 193 Decompression speed is slowest among the choices. The kernel
304 size is about 10% smaller with bzip2 194 size is about 10% smaller with bzip2, in comparison to gzip.
305 Bzip2 uses a large amount of memory. 195 Bzip2 uses a large amount of memory. For modern kernels you
306 will need at least 8MB RAM or more f 196 will need at least 8MB RAM or more for booting.
307 197
308 config KERNEL_LZMA 198 config KERNEL_LZMA
309 bool "LZMA" 199 bool "LZMA"
310 depends on HAVE_KERNEL_LZMA 200 depends on HAVE_KERNEL_LZMA
311 help 201 help
312 This compression algorithm's ratio i 202 This compression algorithm's ratio is best. Decompression speed
313 is between gzip and bzip2. Compress 203 is between gzip and bzip2. Compression is slowest.
314 The kernel size is about 33% smaller 204 The kernel size is about 33% smaller with LZMA in comparison to gzip.
315 205
316 config KERNEL_XZ 206 config KERNEL_XZ
317 bool "XZ" 207 bool "XZ"
318 depends on HAVE_KERNEL_XZ 208 depends on HAVE_KERNEL_XZ
319 help 209 help
320 XZ uses the LZMA2 algorithm and inst 210 XZ uses the LZMA2 algorithm and instruction set specific
321 BCJ filters which can improve compre 211 BCJ filters which can improve compression ratio of executable
322 code. The size of the kernel is abou 212 code. The size of the kernel is about 30% smaller with XZ in
323 comparison to gzip. On architectures 213 comparison to gzip. On architectures for which there is a BCJ
324 filter (i386, x86_64, ARM, ARM64, RI !! 214 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
325 and SPARC), XZ will create a few per !! 215 will create a few percent smaller kernel than plain LZMA.
326 plain LZMA. <<
327 216
328 The speed is about the same as with 217 The speed is about the same as with LZMA: The decompression
329 speed of XZ is better than that of b 218 speed of XZ is better than that of bzip2 but worse than gzip
330 and LZO. Compression is slow. 219 and LZO. Compression is slow.
331 220
332 config KERNEL_LZO 221 config KERNEL_LZO
333 bool "LZO" 222 bool "LZO"
334 depends on HAVE_KERNEL_LZO 223 depends on HAVE_KERNEL_LZO
335 help 224 help
336 Its compression ratio is the poorest 225 Its compression ratio is the poorest among the choices. The kernel
337 size is about 10% bigger than gzip; 226 size is about 10% bigger than gzip; however its speed
338 (both compression and decompression) 227 (both compression and decompression) is the fastest.
339 228
340 config KERNEL_LZ4 229 config KERNEL_LZ4
341 bool "LZ4" 230 bool "LZ4"
342 depends on HAVE_KERNEL_LZ4 231 depends on HAVE_KERNEL_LZ4
343 help 232 help
344 LZ4 is an LZ77-type compressor with 233 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
345 A preliminary version of LZ4 de/comp 234 A preliminary version of LZ4 de/compression tool is available at
346 <https://code.google.com/p/lz4/>. 235 <https://code.google.com/p/lz4/>.
347 236
348 Its compression ratio is worse than 237 Its compression ratio is worse than LZO. The size of the kernel
349 is about 8% bigger than LZO. But the 238 is about 8% bigger than LZO. But the decompression speed is
350 faster than LZO. 239 faster than LZO.
351 240
352 config KERNEL_ZSTD <<
353 bool "ZSTD" <<
354 depends on HAVE_KERNEL_ZSTD <<
355 help <<
356 ZSTD is a compression algorithm targ <<
357 with fast decompression speed. It wi <<
358 decompress around the same speed as <<
359 will need at least 192 KB RAM or mor <<
360 line tool is required for compressio <<
361 <<
362 config KERNEL_UNCOMPRESSED 241 config KERNEL_UNCOMPRESSED
363 bool "None" 242 bool "None"
364 depends on HAVE_KERNEL_UNCOMPRESSED 243 depends on HAVE_KERNEL_UNCOMPRESSED
365 help 244 help
366 Produce uncompressed kernel image. T 245 Produce uncompressed kernel image. This option is usually not what
367 you want. It is useful for debugging 246 you want. It is useful for debugging the kernel in slow simulation
368 environments, where decompressing an 247 environments, where decompressing and moving the kernel is awfully
369 slow. This option allows early boot 248 slow. This option allows early boot code to skip the decompressor
370 and jump right at uncompressed kerne 249 and jump right at uncompressed kernel image.
371 250
372 endchoice 251 endchoice
373 252
374 config DEFAULT_INIT <<
375 string "Default init path" <<
376 default "" <<
377 help <<
378 This option determines the default i <<
379 option is passed on the kernel comma <<
380 not present, we will still then move <<
381 locations (e.g. /sbin/init, etc). If <<
382 the fallback list when init= is not <<
383 <<
384 config DEFAULT_HOSTNAME 253 config DEFAULT_HOSTNAME
385 string "Default hostname" 254 string "Default hostname"
386 default "(none)" 255 default "(none)"
387 help 256 help
388 This option determines the default s 257 This option determines the default system hostname before userspace
389 calls sethostname(2). The kernel tra 258 calls sethostname(2). The kernel traditionally uses "(none)" here,
390 but you may wish to use a different 259 but you may wish to use a different default here to make a minimal
391 system more usable with less configu 260 system more usable with less configuration.
392 261
>> 262 #
>> 263 # For some reason microblaze and nios2 hard code SWAP=n. Hopefully we can
>> 264 # add proper SWAP support to them, in which case this can be remove.
>> 265 #
>> 266 config ARCH_NO_SWAP
>> 267 bool
>> 268
>> 269 config SWAP
>> 270 bool "Support for paging of anonymous memory (swap)"
>> 271 depends on MMU && BLOCK && !ARCH_NO_SWAP
>> 272 default y
>> 273 help
>> 274 This option allows you to choose whether you want to have support
>> 275 for so called swap devices or swap files in your kernel that are
>> 276 used to provide more virtual memory than the actual RAM present
>> 277 in your computer. If unsure say Y.
>> 278
393 config SYSVIPC 279 config SYSVIPC
394 bool "System V IPC" 280 bool "System V IPC"
395 help !! 281 ---help---
396 Inter Process Communication is a sui 282 Inter Process Communication is a suite of library functions and
397 system calls which let processes (ru 283 system calls which let processes (running programs) synchronize and
398 exchange information. It is generall 284 exchange information. It is generally considered to be a good thing,
399 and some programs won't run unless y 285 and some programs won't run unless you say Y here. In particular, if
400 you want to run the DOS emulator dos 286 you want to run the DOS emulator dosemu under Linux (read the
401 DOSEMU-HOWTO, available from <http:/ 287 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
402 you'll need to say Y here. 288 you'll need to say Y here.
403 289
404 You can find documentation about IPC 290 You can find documentation about IPC with "info ipc" and also in
405 section 6.4 of the Linux Programmer' 291 section 6.4 of the Linux Programmer's Guide, available from
406 <http://www.tldp.org/guides.html>. 292 <http://www.tldp.org/guides.html>.
407 293
408 config SYSVIPC_SYSCTL 294 config SYSVIPC_SYSCTL
409 bool 295 bool
410 depends on SYSVIPC 296 depends on SYSVIPC
411 depends on SYSCTL 297 depends on SYSCTL
412 default y 298 default y
413 299
414 config SYSVIPC_COMPAT <<
415 def_bool y <<
416 depends on COMPAT && SYSVIPC <<
417 <<
418 config POSIX_MQUEUE 300 config POSIX_MQUEUE
419 bool "POSIX Message Queues" 301 bool "POSIX Message Queues"
420 depends on NET 302 depends on NET
421 help !! 303 ---help---
422 POSIX variant of message queues is a 304 POSIX variant of message queues is a part of IPC. In POSIX message
423 queues every message has a priority 305 queues every message has a priority which decides about succession
424 of receiving it by a process. If you 306 of receiving it by a process. If you want to compile and run
425 programs written e.g. for Solaris wi 307 programs written e.g. for Solaris with use of its POSIX message
426 queues (functions mq_*) say Y here. 308 queues (functions mq_*) say Y here.
427 309
428 POSIX message queues are visible as 310 POSIX message queues are visible as a filesystem called 'mqueue'
429 and can be mounted somewhere if you 311 and can be mounted somewhere if you want to do filesystem
430 operations on message queues. 312 operations on message queues.
431 313
432 If unsure, say Y. 314 If unsure, say Y.
433 315
434 config POSIX_MQUEUE_SYSCTL 316 config POSIX_MQUEUE_SYSCTL
435 bool 317 bool
436 depends on POSIX_MQUEUE 318 depends on POSIX_MQUEUE
437 depends on SYSCTL 319 depends on SYSCTL
438 default y 320 default y
439 321
440 config WATCH_QUEUE <<
441 bool "General notification queue" <<
442 default n <<
443 help <<
444 <<
445 This is a general notification queue <<
446 userspace by splicing them into pipe <<
447 with watches for key/keyring change <<
448 notifications. <<
449 <<
450 See Documentation/core-api/watch_que <<
451 <<
452 config CROSS_MEMORY_ATTACH 322 config CROSS_MEMORY_ATTACH
453 bool "Enable process_vm_readv/writev s 323 bool "Enable process_vm_readv/writev syscalls"
454 depends on MMU 324 depends on MMU
455 default y 325 default y
456 help 326 help
457 Enabling this option adds the system 327 Enabling this option adds the system calls process_vm_readv and
458 process_vm_writev which allow a proc 328 process_vm_writev which allow a process with the correct privileges
459 to directly read from or write to an 329 to directly read from or write to another process' address space.
460 See the man page for more details. 330 See the man page for more details.
461 331
462 config USELIB 332 config USELIB
463 bool "uselib syscall (for libc5 and ea !! 333 bool "uselib syscall"
464 default ALPHA || M68K || SPARC !! 334 def_bool ALPHA || M68K || SPARC || X86_32 || IA32_EMULATION
465 help 335 help
466 This option enables the uselib sysca 336 This option enables the uselib syscall, a system call used in the
467 dynamic linker from libc5 and earlie 337 dynamic linker from libc5 and earlier. glibc does not use this
468 system call. If you intend to run p 338 system call. If you intend to run programs built on libc5 or
469 earlier, you may need to enable this 339 earlier, you may need to enable this syscall. Current systems
470 running glibc can safely disable thi 340 running glibc can safely disable this.
471 341
472 config AUDIT 342 config AUDIT
473 bool "Auditing support" 343 bool "Auditing support"
474 depends on NET 344 depends on NET
475 help 345 help
476 Enable auditing infrastructure that 346 Enable auditing infrastructure that can be used with another
477 kernel subsystem, such as SELinux (w 347 kernel subsystem, such as SELinux (which requires this for
478 logging of avc messages output). Sy 348 logging of avc messages output). System call auditing is included
479 on architectures which support it. 349 on architectures which support it.
480 350
481 config HAVE_ARCH_AUDITSYSCALL 351 config HAVE_ARCH_AUDITSYSCALL
482 bool 352 bool
483 353
484 config AUDITSYSCALL 354 config AUDITSYSCALL
485 def_bool y 355 def_bool y
486 depends on AUDIT && HAVE_ARCH_AUDITSYS 356 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
487 select FSNOTIFY 357 select FSNOTIFY
488 358
489 source "kernel/irq/Kconfig" 359 source "kernel/irq/Kconfig"
490 source "kernel/time/Kconfig" 360 source "kernel/time/Kconfig"
491 source "kernel/bpf/Kconfig" <<
492 source "kernel/Kconfig.preempt" 361 source "kernel/Kconfig.preempt"
493 362
494 menu "CPU/Task time and stats accounting" 363 menu "CPU/Task time and stats accounting"
495 364
496 config VIRT_CPU_ACCOUNTING 365 config VIRT_CPU_ACCOUNTING
497 bool 366 bool
498 367
499 choice 368 choice
500 prompt "Cputime accounting" 369 prompt "Cputime accounting"
501 default TICK_CPU_ACCOUNTING !! 370 default TICK_CPU_ACCOUNTING if !PPC64
>> 371 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
502 372
503 # Kind of a stub config for the pure tick base 373 # Kind of a stub config for the pure tick based cputime accounting
504 config TICK_CPU_ACCOUNTING 374 config TICK_CPU_ACCOUNTING
505 bool "Simple tick based cputime accoun 375 bool "Simple tick based cputime accounting"
506 depends on !S390 && !NO_HZ_FULL 376 depends on !S390 && !NO_HZ_FULL
507 help 377 help
508 This is the basic tick based cputime 378 This is the basic tick based cputime accounting that maintains
509 statistics about user, system and id 379 statistics about user, system and idle time spent on per jiffies
510 granularity. 380 granularity.
511 381
512 If unsure, say Y. 382 If unsure, say Y.
513 383
514 config VIRT_CPU_ACCOUNTING_NATIVE 384 config VIRT_CPU_ACCOUNTING_NATIVE
515 bool "Deterministic task and CPU time 385 bool "Deterministic task and CPU time accounting"
516 depends on HAVE_VIRT_CPU_ACCOUNTING && 386 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
517 select VIRT_CPU_ACCOUNTING 387 select VIRT_CPU_ACCOUNTING
518 help 388 help
519 Select this option to enable more ac 389 Select this option to enable more accurate task and CPU time
520 accounting. This is done by reading 390 accounting. This is done by reading a CPU counter on each
521 kernel entry and exit and on transit 391 kernel entry and exit and on transitions within the kernel
522 between system, softirq and hardirq 392 between system, softirq and hardirq state, so there is a
523 small performance impact. In the ca 393 small performance impact. In the case of s390 or IBM POWER > 5,
524 this also enables accounting of stol 394 this also enables accounting of stolen time on logically-partitioned
525 systems. 395 systems.
526 396
527 config VIRT_CPU_ACCOUNTING_GEN 397 config VIRT_CPU_ACCOUNTING_GEN
528 bool "Full dynticks CPU time accountin 398 bool "Full dynticks CPU time accounting"
529 depends on HAVE_CONTEXT_TRACKING_USER !! 399 depends on HAVE_CONTEXT_TRACKING
530 depends on HAVE_VIRT_CPU_ACCOUNTING_GE 400 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
531 depends on GENERIC_CLOCKEVENTS 401 depends on GENERIC_CLOCKEVENTS
532 select VIRT_CPU_ACCOUNTING 402 select VIRT_CPU_ACCOUNTING
533 select CONTEXT_TRACKING_USER !! 403 select CONTEXT_TRACKING
534 help 404 help
535 Select this option to enable task an 405 Select this option to enable task and CPU time accounting on full
536 dynticks systems. This accounting is 406 dynticks systems. This accounting is implemented by watching every
537 kernel-user boundaries using the con 407 kernel-user boundaries using the context tracking subsystem.
538 The accounting is thus performed at 408 The accounting is thus performed at the expense of some significant
539 overhead. 409 overhead.
540 410
541 For now this is only useful if you a 411 For now this is only useful if you are working on the full
542 dynticks subsystem development. 412 dynticks subsystem development.
543 413
544 If unsure, say N. 414 If unsure, say N.
545 415
546 endchoice 416 endchoice
547 417
548 config IRQ_TIME_ACCOUNTING 418 config IRQ_TIME_ACCOUNTING
549 bool "Fine granularity task level IRQ 419 bool "Fine granularity task level IRQ time accounting"
550 depends on HAVE_IRQ_TIME_ACCOUNTING && 420 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
551 help 421 help
552 Select this option to enable fine gr 422 Select this option to enable fine granularity task irq time
553 accounting. This is done by reading 423 accounting. This is done by reading a timestamp on each
554 transitions between softirq and hard 424 transitions between softirq and hardirq state, so there can be a
555 small performance impact. 425 small performance impact.
556 426
557 If in doubt, say N here. 427 If in doubt, say N here.
558 428
559 config HAVE_SCHED_AVG_IRQ 429 config HAVE_SCHED_AVG_IRQ
560 def_bool y 430 def_bool y
561 depends on IRQ_TIME_ACCOUNTING || PARA 431 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING
562 depends on SMP 432 depends on SMP
563 433
564 config SCHED_HW_PRESSURE <<
565 bool <<
566 default y if ARM && ARM_CPU_TOPOLOGY <<
567 default y if ARM64 <<
568 depends on SMP <<
569 depends on CPU_FREQ_THERMAL <<
570 help <<
571 Select this option to enable HW pres <<
572 scheduler. HW pressure is the value <<
573 that reflects the reduction in CPU c <<
574 HW throttling. HW throttling occurs <<
575 a CPU is capped due to high operatin <<
576 <<
577 If selected, the scheduler will be a <<
578 i.e. put less load on throttled CPUs <<
579 <<
580 This requires the architecture to im <<
581 arch_update_hw_pressure() and arch_s <<
582 <<
583 config BSD_PROCESS_ACCT 434 config BSD_PROCESS_ACCT
584 bool "BSD Process Accounting" 435 bool "BSD Process Accounting"
585 depends on MULTIUSER 436 depends on MULTIUSER
586 help 437 help
587 If you say Y here, a user level prog 438 If you say Y here, a user level program will be able to instruct the
588 kernel (via a special system call) t 439 kernel (via a special system call) to write process accounting
589 information to a file: whenever a pr 440 information to a file: whenever a process exits, information about
590 that process will be appended to the 441 that process will be appended to the file by the kernel. The
591 information includes things such as 442 information includes things such as creation time, owning user,
592 command name, memory usage, controll 443 command name, memory usage, controlling terminal etc. (the complete
593 list is in the struct acct in <file: 444 list is in the struct acct in <file:include/linux/acct.h>). It is
594 up to the user level program to do u 445 up to the user level program to do useful things with this
595 information. This is generally a go 446 information. This is generally a good idea, so say Y.
596 447
597 config BSD_PROCESS_ACCT_V3 448 config BSD_PROCESS_ACCT_V3
598 bool "BSD Process Accounting version 3 449 bool "BSD Process Accounting version 3 file format"
599 depends on BSD_PROCESS_ACCT 450 depends on BSD_PROCESS_ACCT
600 default n 451 default n
601 help 452 help
602 If you say Y here, the process accou 453 If you say Y here, the process accounting information is written
603 in a new file format that also logs 454 in a new file format that also logs the process IDs of each
604 process and its parent. Note that th 455 process and its parent. Note that this file format is incompatible
605 with previous v0/v1/v2 file formats, 456 with previous v0/v1/v2 file formats, so you will need updated tools
606 for processing it. A preliminary ver 457 for processing it. A preliminary version of these tools is available
607 at <http://www.gnu.org/software/acct 458 at <http://www.gnu.org/software/acct/>.
608 459
609 config TASKSTATS 460 config TASKSTATS
610 bool "Export task/process statistics t 461 bool "Export task/process statistics through netlink"
611 depends on NET 462 depends on NET
612 depends on MULTIUSER 463 depends on MULTIUSER
613 default n 464 default n
614 help 465 help
615 Export selected statistics for tasks 466 Export selected statistics for tasks/processes through the
616 generic netlink interface. Unlike BS 467 generic netlink interface. Unlike BSD process accounting, the
617 statistics are available during the 468 statistics are available during the lifetime of tasks/processes as
618 responses to commands. Like BSD acco 469 responses to commands. Like BSD accounting, they are sent to user
619 space on task exit. 470 space on task exit.
620 471
621 Say N if unsure. 472 Say N if unsure.
622 473
623 config TASK_DELAY_ACCT 474 config TASK_DELAY_ACCT
624 bool "Enable per-task delay accounting 475 bool "Enable per-task delay accounting"
625 depends on TASKSTATS 476 depends on TASKSTATS
626 select SCHED_INFO 477 select SCHED_INFO
627 help 478 help
628 Collect information on time spent by 479 Collect information on time spent by a task waiting for system
629 resources like cpu, synchronous bloc 480 resources like cpu, synchronous block I/O completion and swapping
630 in pages. Such statistics can help i 481 in pages. Such statistics can help in setting a task's priorities
631 relative to other tasks for cpu, io, 482 relative to other tasks for cpu, io, rss limits etc.
632 483
633 Say N if unsure. 484 Say N if unsure.
634 485
635 config TASK_XACCT 486 config TASK_XACCT
636 bool "Enable extended accounting over 487 bool "Enable extended accounting over taskstats"
637 depends on TASKSTATS 488 depends on TASKSTATS
638 help 489 help
639 Collect extended task accounting dat 490 Collect extended task accounting data and send the data
640 to userland for processing over the 491 to userland for processing over the taskstats interface.
641 492
642 Say N if unsure. 493 Say N if unsure.
643 494
644 config TASK_IO_ACCOUNTING 495 config TASK_IO_ACCOUNTING
645 bool "Enable per-task storage I/O acco 496 bool "Enable per-task storage I/O accounting"
646 depends on TASK_XACCT 497 depends on TASK_XACCT
647 help 498 help
648 Collect information on the number of 499 Collect information on the number of bytes of storage I/O which this
649 task has caused. 500 task has caused.
650 501
651 Say N if unsure. 502 Say N if unsure.
652 503
653 config PSI 504 config PSI
654 bool "Pressure stall information track 505 bool "Pressure stall information tracking"
655 select KERNFS <<
656 help 506 help
657 Collect metrics that indicate how ov 507 Collect metrics that indicate how overcommitted the CPU, memory,
658 and IO capacity are in the system. 508 and IO capacity are in the system.
659 509
660 If you say Y here, the kernel will c 510 If you say Y here, the kernel will create /proc/pressure/ with the
661 pressure statistics files cpu, memor 511 pressure statistics files cpu, memory, and io. These will indicate
662 the share of walltime in which some 512 the share of walltime in which some or all tasks in the system are
663 delayed due to contention of the res 513 delayed due to contention of the respective resource.
664 514
665 In kernels with cgroup support, cgro 515 In kernels with cgroup support, cgroups (cgroup2 only) will
666 have cpu.pressure, memory.pressure, 516 have cpu.pressure, memory.pressure, and io.pressure files,
667 which aggregate pressure stalls for 517 which aggregate pressure stalls for the grouped tasks only.
668 518
669 For more details see Documentation/a !! 519 For more details see Documentation/accounting/psi.txt.
670 520
671 Say N if unsure. 521 Say N if unsure.
672 522
673 config PSI_DEFAULT_DISABLED 523 config PSI_DEFAULT_DISABLED
674 bool "Require boot parameter to enable 524 bool "Require boot parameter to enable pressure stall information tracking"
675 default n 525 default n
676 depends on PSI 526 depends on PSI
677 help 527 help
678 If set, pressure stall information t 528 If set, pressure stall information tracking will be disabled
679 per default but can be enabled throu 529 per default but can be enabled through passing psi=1 on the
680 kernel commandline during boot. 530 kernel commandline during boot.
681 531
682 This feature adds some code to the t 532 This feature adds some code to the task wakeup and sleep
683 paths of the scheduler. The overhead 533 paths of the scheduler. The overhead is too low to affect
684 common scheduling-intense workloads 534 common scheduling-intense workloads in practice (such as
685 webservers, memcache), but it does s 535 webservers, memcache), but it does show up in artificial
686 scheduler stress tests, such as hack 536 scheduler stress tests, such as hackbench.
687 537
688 If you are paranoid and not sure wha 538 If you are paranoid and not sure what the kernel will be
689 used for, say Y. 539 used for, say Y.
690 540
691 Say N if unsure. 541 Say N if unsure.
692 542
693 endmenu # "CPU/Task time and stats accounting" 543 endmenu # "CPU/Task time and stats accounting"
694 544
695 config CPU_ISOLATION 545 config CPU_ISOLATION
696 bool "CPU isolation" 546 bool "CPU isolation"
697 depends on SMP || COMPILE_TEST 547 depends on SMP || COMPILE_TEST
698 default y 548 default y
699 help 549 help
700 Make sure that CPUs running critical 550 Make sure that CPUs running critical tasks are not disturbed by
701 any source of "noise" such as unboun 551 any source of "noise" such as unbound workqueues, timers, kthreads...
702 Unbound jobs get offloaded to housek 552 Unbound jobs get offloaded to housekeeping CPUs. This is driven by
703 the "isolcpus=" boot parameter. 553 the "isolcpus=" boot parameter.
704 554
705 Say Y if unsure. 555 Say Y if unsure.
706 556
707 source "kernel/rcu/Kconfig" 557 source "kernel/rcu/Kconfig"
708 558
>> 559 config BUILD_BIN2C
>> 560 bool
>> 561 default n
>> 562
709 config IKCONFIG 563 config IKCONFIG
710 tristate "Kernel .config support" 564 tristate "Kernel .config support"
711 help !! 565 select BUILD_BIN2C
>> 566 ---help---
712 This option enables the complete Lin 567 This option enables the complete Linux kernel ".config" file
713 contents to be saved in the kernel. 568 contents to be saved in the kernel. It provides documentation
714 of which kernel options are used in 569 of which kernel options are used in a running kernel or in an
715 on-disk kernel. This information ca 570 on-disk kernel. This information can be extracted from the kernel
716 image file with the script scripts/e 571 image file with the script scripts/extract-ikconfig and used as
717 input to rebuild the current kernel 572 input to rebuild the current kernel or to build another kernel.
718 It can also be extracted from a runn 573 It can also be extracted from a running kernel by reading
719 /proc/config.gz if enabled (below). 574 /proc/config.gz if enabled (below).
720 575
721 config IKCONFIG_PROC 576 config IKCONFIG_PROC
722 bool "Enable access to .config through 577 bool "Enable access to .config through /proc/config.gz"
723 depends on IKCONFIG && PROC_FS 578 depends on IKCONFIG && PROC_FS
724 help !! 579 ---help---
725 This option enables access to the ke 580 This option enables access to the kernel configuration file
726 through /proc/config.gz. 581 through /proc/config.gz.
727 582
728 config IKHEADERS <<
729 tristate "Enable kernel headers throug <<
730 depends on SYSFS <<
731 help <<
732 This option enables access to the in <<
733 the build process. These can be used <<
734 or similar programs. If you build t <<
735 kheaders.ko is built which can be lo <<
736 <<
737 config LOG_BUF_SHIFT 583 config LOG_BUF_SHIFT
738 int "Kernel log buffer size (16 => 64K 584 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
739 range 12 25 585 range 12 25
740 default 17 586 default 17
741 depends on PRINTK 587 depends on PRINTK
742 help 588 help
743 Select the minimal kernel log buffer 589 Select the minimal kernel log buffer size as a power of 2.
744 The final size is affected by LOG_CP 590 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
745 parameter, see below. Any higher siz 591 parameter, see below. Any higher size also might be forced
746 by "log_buf_len" boot parameter. 592 by "log_buf_len" boot parameter.
747 593
748 Examples: 594 Examples:
749 17 => 128 KB 595 17 => 128 KB
750 16 => 64 KB 596 16 => 64 KB
751 15 => 32 KB 597 15 => 32 KB
752 14 => 16 KB 598 14 => 16 KB
753 13 => 8 KB 599 13 => 8 KB
754 12 => 4 KB 600 12 => 4 KB
755 601
756 config LOG_CPU_MAX_BUF_SHIFT 602 config LOG_CPU_MAX_BUF_SHIFT
757 int "CPU kernel log buffer size contri 603 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
758 depends on SMP 604 depends on SMP
759 range 0 21 605 range 0 21
>> 606 default 12 if !BASE_SMALL
760 default 0 if BASE_SMALL 607 default 0 if BASE_SMALL
761 default 12 <<
762 depends on PRINTK 608 depends on PRINTK
763 help 609 help
764 This option allows to increase the d 610 This option allows to increase the default ring buffer size
765 according to the number of CPUs. The 611 according to the number of CPUs. The value defines the contribution
766 of each CPU as a power of 2. The use 612 of each CPU as a power of 2. The used space is typically only few
767 lines however it might be much more 613 lines however it might be much more when problems are reported,
768 e.g. backtraces. 614 e.g. backtraces.
769 615
770 The increased size means that a new 616 The increased size means that a new buffer has to be allocated and
771 the original static one is unused. I 617 the original static one is unused. It makes sense only on systems
772 with more CPUs. Therefore this value 618 with more CPUs. Therefore this value is used only when the sum of
773 contributions is greater than the ha 619 contributions is greater than the half of the default kernel ring
774 buffer as defined by LOG_BUF_SHIFT. 620 buffer as defined by LOG_BUF_SHIFT. The default values are set
775 so that more than 16 CPUs are needed !! 621 so that more than 64 CPUs are needed to trigger the allocation.
776 622
777 Also this option is ignored when "lo 623 Also this option is ignored when "log_buf_len" kernel parameter is
778 used as it forces an exact (power of 624 used as it forces an exact (power of two) size of the ring buffer.
779 625
780 The number of possible CPUs is used 626 The number of possible CPUs is used for this computation ignoring
781 hotplugging making the computation o 627 hotplugging making the computation optimal for the worst case
782 scenario while allowing a simple alg 628 scenario while allowing a simple algorithm to be used from bootup.
783 629
784 Examples shift values and their mean 630 Examples shift values and their meaning:
785 17 => 128 KB for each CPU 631 17 => 128 KB for each CPU
786 16 => 64 KB for each CPU 632 16 => 64 KB for each CPU
787 15 => 32 KB for each CPU 633 15 => 32 KB for each CPU
788 14 => 16 KB for each CPU 634 14 => 16 KB for each CPU
789 13 => 8 KB for each CPU 635 13 => 8 KB for each CPU
790 12 => 4 KB for each CPU 636 12 => 4 KB for each CPU
791 637
792 config PRINTK_INDEX !! 638 config PRINTK_SAFE_LOG_BUF_SHIFT
793 bool "Printk indexing debugfs interfac !! 639 int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)"
794 depends on PRINTK && DEBUG_FS !! 640 range 10 21
795 help !! 641 default 13
796 Add support for indexing of all prin !! 642 depends on PRINTK
797 at <debugfs>/printk/index/<module>. !! 643 help
798 !! 644 Select the size of an alternate printk per-CPU buffer where messages
799 This can be used as part of maintain !! 645 printed from usafe contexts are temporary stored. One example would
800 /dev/kmsg, as it permits auditing th !! 646 be NMI messages, another one - printk recursion. The messages are
801 kernel, allowing detection of cases !! 647 copied to the main log buffer in a safe context to avoid a deadlock.
802 changed or no longer present. !! 648 The value defines the size as a power of 2.
>> 649
>> 650 Those messages are rare and limited. The largest one is when
>> 651 a backtrace is printed. It usually fits into 4KB. Select
>> 652 8KB if you want to be on the safe side.
803 653
804 There is no additional runtime cost !! 654 Examples:
>> 655 17 => 128 KB for each CPU
>> 656 16 => 64 KB for each CPU
>> 657 15 => 32 KB for each CPU
>> 658 14 => 16 KB for each CPU
>> 659 13 => 8 KB for each CPU
>> 660 12 => 4 KB for each CPU
805 661
806 # 662 #
807 # Architectures with an unreliable sched_clock 663 # Architectures with an unreliable sched_clock() should select this:
808 # 664 #
809 config HAVE_UNSTABLE_SCHED_CLOCK 665 config HAVE_UNSTABLE_SCHED_CLOCK
810 bool 666 bool
811 667
812 config GENERIC_SCHED_CLOCK 668 config GENERIC_SCHED_CLOCK
813 bool 669 bool
814 670
815 menu "Scheduler features" <<
816 <<
817 config UCLAMP_TASK <<
818 bool "Enable utilization clamping for <<
819 depends on CPU_FREQ_GOV_SCHEDUTIL <<
820 help <<
821 This feature enables the scheduler t <<
822 of each CPU based on RUNNABLE tasks <<
823 <<
824 With this option, the user can speci <<
825 utilization allowed for RUNNABLE tas <<
826 the maximum frequency a task should <<
827 defines the minimum frequency it sho <<
828 <<
829 Both min and max utilization clamp v <<
830 aiming at improving its frequency se <<
831 enforce or grant any specific bandwi <<
832 <<
833 If in doubt, say N. <<
834 <<
835 config UCLAMP_BUCKETS_COUNT <<
836 int "Number of supported utilization c <<
837 range 5 20 <<
838 default 5 <<
839 depends on UCLAMP_TASK <<
840 help <<
841 Defines the number of clamp buckets <<
842 will be SCHED_CAPACITY_SCALE/UCLAMP_ <<
843 number of clamp buckets the finer th <<
844 the precision of clamping aggregatio <<
845 <<
846 For example, with the minimum config <<
847 clamp buckets tracking 20% utilizati <<
848 be refcounted in the [20..39]% bucke <<
849 effective value to 25%. <<
850 If a second 30% boosted task should <<
851 that task will be refcounted in the <<
852 it will boost the bucket clamp effec <<
853 The clamp effective value of a bucke <<
854 (20% in the example above) when ther <<
855 that bucket. <<
856 <<
857 An additional boost/capping margin c <<
858 example above the 25% task will be b <<
859 CPU. If that should be considered no <<
860 it's always possible to reduce the m <<
861 clamp buckets to trade off used memo <<
862 precision. <<
863 <<
864 If in doubt, use the default value. <<
865 <<
866 endmenu <<
867 <<
868 # 671 #
869 # For architectures that want to enable the su 672 # For architectures that want to enable the support for NUMA-affine scheduler
870 # balancing logic: 673 # balancing logic:
871 # 674 #
872 config ARCH_SUPPORTS_NUMA_BALANCING 675 config ARCH_SUPPORTS_NUMA_BALANCING
873 bool 676 bool
874 677
875 # 678 #
876 # For architectures that prefer to flush all T 679 # For architectures that prefer to flush all TLBs after a number of pages
877 # are unmapped instead of sending one IPI per 680 # are unmapped instead of sending one IPI per page to flush. The architecture
878 # must provide guarantees on what happens if a 681 # must provide guarantees on what happens if a clean TLB cache entry is
879 # written after the unmap. Details are in mm/r 682 # written after the unmap. Details are in mm/rmap.c near the check for
880 # should_defer_flush. The architecture should 683 # should_defer_flush. The architecture should also consider if the full flush
881 # and the refill costs are offset by the savin 684 # and the refill costs are offset by the savings of sending fewer IPIs.
882 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 685 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
883 bool 686 bool
884 687
885 config CC_HAS_INT128 <<
886 def_bool !$(cc-option,$(m64-flag) -D__ <<
887 <<
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 # 688 #
915 # For architectures that know their GCC __int1 689 # For architectures that know their GCC __int128 support is sound
916 # 690 #
917 config ARCH_SUPPORTS_INT128 691 config ARCH_SUPPORTS_INT128
918 bool 692 bool
919 693
920 # For architectures that (ab)use NUMA to repre 694 # For architectures that (ab)use NUMA to represent different memory regions
921 # all cpu-local but of different latencies, su 695 # all cpu-local but of different latencies, such as SuperH.
922 # 696 #
923 config ARCH_WANT_NUMA_VARIABLE_LOCALITY 697 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
924 bool 698 bool
925 699
926 config NUMA_BALANCING 700 config NUMA_BALANCING
927 bool "Memory placement aware NUMA sche 701 bool "Memory placement aware NUMA scheduler"
928 depends on ARCH_SUPPORTS_NUMA_BALANCIN 702 depends on ARCH_SUPPORTS_NUMA_BALANCING
929 depends on !ARCH_WANT_NUMA_VARIABLE_LO 703 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
930 depends on SMP && NUMA && MIGRATION && !! 704 depends on SMP && NUMA && MIGRATION
931 help 705 help
932 This option adds support for automat 706 This option adds support for automatic NUMA aware memory/task placement.
933 The mechanism is quite primitive and 707 The mechanism is quite primitive and is based on migrating memory when
934 it has references to the node the ta 708 it has references to the node the task is running on.
935 709
936 This system will be inactive on UMA 710 This system will be inactive on UMA systems.
937 711
938 config NUMA_BALANCING_DEFAULT_ENABLED 712 config NUMA_BALANCING_DEFAULT_ENABLED
939 bool "Automatically enable NUMA aware 713 bool "Automatically enable NUMA aware memory/task placement"
940 default y 714 default y
941 depends on NUMA_BALANCING 715 depends on NUMA_BALANCING
942 help 716 help
943 If set, automatic NUMA balancing wil 717 If set, automatic NUMA balancing will be enabled if running on a NUMA
944 machine. 718 machine.
945 719
946 config SLAB_OBJ_EXT <<
947 bool <<
948 <<
949 menuconfig CGROUPS 720 menuconfig CGROUPS
950 bool "Control Group support" 721 bool "Control Group support"
951 select KERNFS 722 select KERNFS
952 help 723 help
953 This option adds support for groupin 724 This option adds support for grouping sets of processes together, for
954 use with process control subsystems 725 use with process control subsystems such as Cpusets, CFS, memory
955 controls or device isolation. 726 controls or device isolation.
956 See 727 See
957 - Documentation/scheduler/sche !! 728 - Documentation/scheduler/sched-design-CFS.txt (CFS)
958 - Documentation/admin-guide/cg !! 729 - Documentation/cgroup-v1/ (features for grouping, isolation
959 and 730 and resource control)
960 731
961 Say N if unsure. 732 Say N if unsure.
962 733
963 if CGROUPS 734 if CGROUPS
964 735
965 config PAGE_COUNTER 736 config PAGE_COUNTER
966 bool !! 737 bool
967 <<
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. <<
977 738
978 config MEMCG 739 config MEMCG
979 bool "Memory controller" 740 bool "Memory controller"
980 select PAGE_COUNTER 741 select PAGE_COUNTER
981 select EVENTFD 742 select EVENTFD
982 select SLAB_OBJ_EXT <<
983 help 743 help
984 Provides control over the memory foo 744 Provides control over the memory footprint of tasks in a cgroup.
985 745
986 config MEMCG_V1 !! 746 config MEMCG_SWAP
987 bool "Legacy cgroup v1 memory controll !! 747 bool "Swap controller"
988 depends on MEMCG !! 748 depends on MEMCG && SWAP
989 default n <<
990 help 749 help
991 Legacy cgroup v1 memory controller w !! 750 Provides control over the swap space consumed by tasks in a cgroup.
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 751
1001 Say N if unsure. !! 752 config MEMCG_SWAP_ENABLED
>> 753 bool "Swap controller enabled by default"
>> 754 depends on MEMCG_SWAP
>> 755 default y
>> 756 help
>> 757 Memory Resource Controller Swap Extension comes with its price in
>> 758 a bigger memory consumption. General purpose distribution kernels
>> 759 which want to enable the feature but keep it disabled by default
>> 760 and let the user enable it by swapaccount=1 boot command line
>> 761 parameter should have this option unselected.
>> 762 For those who want to have the feature enabled by default should
>> 763 select this option (if, for some reason, they need to disable it
>> 764 then swapaccount=0 does the trick).
>> 765
>> 766 config MEMCG_KMEM
>> 767 bool
>> 768 depends on MEMCG && !SLOB
>> 769 default y
1002 770
1003 config BLK_CGROUP 771 config BLK_CGROUP
1004 bool "IO controller" 772 bool "IO controller"
1005 depends on BLOCK 773 depends on BLOCK
1006 default n 774 default n
1007 help !! 775 ---help---
1008 Generic block IO controller cgroup in 776 Generic block IO controller cgroup interface. This is the common
1009 cgroup interface which should be used 777 cgroup interface which should be used by various IO controlling
1010 policies. 778 policies.
1011 779
1012 Currently, CFQ IO scheduler uses it t 780 Currently, CFQ IO scheduler uses it to recognize task groups and
1013 control disk bandwidth allocation (pr 781 control disk bandwidth allocation (proportional time slice allocation)
1014 to such task groups. It is also used 782 to such task groups. It is also used by bio throttling logic in
1015 block layer to implement upper limit 783 block layer to implement upper limit in IO rates on a device.
1016 784
1017 This option only enables generic Bloc 785 This option only enables generic Block IO controller infrastructure.
1018 One needs to also enable actual IO co 786 One needs to also enable actual IO controlling logic/policy. For
1019 enabling proportional weight division 787 enabling proportional weight division of disk bandwidth in CFQ, set
1020 CONFIG_BFQ_GROUP_IOSCHED=y; for enabl !! 788 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1021 CONFIG_BLK_DEV_THROTTLING=y. 789 CONFIG_BLK_DEV_THROTTLING=y.
1022 790
1023 See Documentation/admin-guide/cgroup- !! 791 See Documentation/cgroup-v1/blkio-controller.txt for more information.
>> 792
>> 793 config DEBUG_BLK_CGROUP
>> 794 bool "IO controller debugging"
>> 795 depends on BLK_CGROUP
>> 796 default n
>> 797 ---help---
>> 798 Enable some debugging help. Currently it exports additional stat
>> 799 files in a cgroup which can be useful for debugging.
1024 800
1025 config CGROUP_WRITEBACK 801 config CGROUP_WRITEBACK
1026 bool 802 bool
1027 depends on MEMCG && BLK_CGROUP 803 depends on MEMCG && BLK_CGROUP
1028 default y 804 default y
1029 805
1030 menuconfig CGROUP_SCHED 806 menuconfig CGROUP_SCHED
1031 bool "CPU controller" 807 bool "CPU controller"
1032 default n 808 default n
1033 help 809 help
1034 This feature lets CPU scheduler rec 810 This feature lets CPU scheduler recognize task groups and control CPU
1035 bandwidth allocation to such task g 811 bandwidth allocation to such task groups. It uses cgroups to group
1036 tasks. 812 tasks.
1037 813
1038 if CGROUP_SCHED 814 if CGROUP_SCHED
1039 config GROUP_SCHED_WEIGHT <<
1040 def_bool n <<
1041 <<
1042 config FAIR_GROUP_SCHED 815 config FAIR_GROUP_SCHED
1043 bool "Group scheduling for SCHED_OTHE 816 bool "Group scheduling for SCHED_OTHER"
1044 depends on CGROUP_SCHED 817 depends on CGROUP_SCHED
1045 select GROUP_SCHED_WEIGHT <<
1046 default CGROUP_SCHED 818 default CGROUP_SCHED
1047 819
1048 config CFS_BANDWIDTH 820 config CFS_BANDWIDTH
1049 bool "CPU bandwidth provisioning for 821 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1050 depends on FAIR_GROUP_SCHED 822 depends on FAIR_GROUP_SCHED
1051 default n 823 default n
1052 help 824 help
1053 This option allows users to define 825 This option allows users to define CPU bandwidth rates (limits) for
1054 tasks running within the fair group 826 tasks running within the fair group scheduler. Groups with no limit
1055 set are considered to be unconstrai 827 set are considered to be unconstrained and will run with no
1056 restriction. 828 restriction.
1057 See Documentation/scheduler/sched-b !! 829 See Documentation/scheduler/sched-bwc.txt for more information.
1058 830
1059 config RT_GROUP_SCHED 831 config RT_GROUP_SCHED
1060 bool "Group scheduling for SCHED_RR/F 832 bool "Group scheduling for SCHED_RR/FIFO"
1061 depends on CGROUP_SCHED 833 depends on CGROUP_SCHED
1062 default n 834 default n
1063 help 835 help
1064 This feature lets you explicitly al 836 This feature lets you explicitly allocate real CPU bandwidth
1065 to task groups. If enabled, it will 837 to task groups. If enabled, it will also make it impossible to
1066 schedule realtime tasks for non-roo 838 schedule realtime tasks for non-root users until you allocate
1067 realtime bandwidth for them. 839 realtime bandwidth for them.
1068 See Documentation/scheduler/sched-r !! 840 See Documentation/scheduler/sched-rt-group.txt for more information.
1069 <<
1070 config EXT_GROUP_SCHED <<
1071 bool <<
1072 depends on SCHED_CLASS_EXT && CGROUP_ <<
1073 select GROUP_SCHED_WEIGHT <<
1074 default y <<
1075 841
1076 endif #CGROUP_SCHED 842 endif #CGROUP_SCHED
1077 843
1078 config SCHED_MM_CID <<
1079 def_bool y <<
1080 depends on SMP && RSEQ <<
1081 <<
1082 config UCLAMP_TASK_GROUP <<
1083 bool "Utilization clamping per group <<
1084 depends on CGROUP_SCHED <<
1085 depends on UCLAMP_TASK <<
1086 default n <<
1087 help <<
1088 This feature enables the scheduler <<
1089 of each CPU based on RUNNABLE tasks <<
1090 <<
1091 When this option is enabled, the us <<
1092 CPU bandwidth which is allowed for <<
1093 The max bandwidth allows to clamp t <<
1094 can use, while the min bandwidth al <<
1095 frequency a task will always use. <<
1096 <<
1097 When task group based utilization c <<
1098 specified task-specific clamp value <<
1099 specified clamp value. Both minimum <<
1100 be bigger than the corresponding cl <<
1101 <<
1102 If in doubt, say N. <<
1103 <<
1104 config CGROUP_PIDS 844 config CGROUP_PIDS
1105 bool "PIDs controller" 845 bool "PIDs controller"
1106 help 846 help
1107 Provides enforcement of process num 847 Provides enforcement of process number limits in the scope of a
1108 cgroup. Any attempt to fork more pr 848 cgroup. Any attempt to fork more processes than is allowed in the
1109 cgroup will fail. PIDs are fundamen 849 cgroup will fail. PIDs are fundamentally a global resource because it
1110 is fairly trivial to reach PID exha 850 is fairly trivial to reach PID exhaustion before you reach even a
1111 conservative kmemcg limit. As a res 851 conservative kmemcg limit. As a result, it is possible to grind a
1112 system to halt without being limite 852 system to halt without being limited by other cgroup policies. The
1113 PIDs controller is designed to stop 853 PIDs controller is designed to stop this from happening.
1114 854
1115 It should be noted that organisatio 855 It should be noted that organisational operations (such as attaching
1116 to a cgroup hierarchy) will *not* b 856 to a cgroup hierarchy) will *not* be blocked by the PIDs controller,
1117 since the PIDs limit only affects a 857 since the PIDs limit only affects a process's ability to fork, not to
1118 attach to a cgroup. 858 attach to a cgroup.
1119 859
1120 config CGROUP_RDMA 860 config CGROUP_RDMA
1121 bool "RDMA controller" 861 bool "RDMA controller"
1122 help 862 help
1123 Provides enforcement of RDMA resour 863 Provides enforcement of RDMA resources defined by IB stack.
1124 It is fairly easy for consumers to 864 It is fairly easy for consumers to exhaust RDMA resources, which
1125 can result into resource unavailabi 865 can result into resource unavailability to other consumers.
1126 RDMA controller is designed to stop 866 RDMA controller is designed to stop this from happening.
1127 Attaching processes with active RDM 867 Attaching processes with active RDMA resources to the cgroup
1128 hierarchy is allowed even if can cr 868 hierarchy is allowed even if can cross the hierarchy's limit.
1129 869
1130 config CGROUP_FREEZER 870 config CGROUP_FREEZER
1131 bool "Freezer controller" 871 bool "Freezer controller"
1132 help 872 help
1133 Provides a way to freeze and unfree 873 Provides a way to freeze and unfreeze all tasks in a
1134 cgroup. 874 cgroup.
1135 875
1136 This option affects the ORIGINAL cg 876 This option affects the ORIGINAL cgroup interface. The cgroup2 memory
1137 controller includes important in-ke 877 controller includes important in-kernel memory consumers per default.
1138 878
1139 If you're using cgroup2, say N. 879 If you're using cgroup2, say N.
1140 880
1141 config CGROUP_HUGETLB 881 config CGROUP_HUGETLB
1142 bool "HugeTLB controller" 882 bool "HugeTLB controller"
1143 depends on HUGETLB_PAGE 883 depends on HUGETLB_PAGE
1144 select PAGE_COUNTER 884 select PAGE_COUNTER
1145 default n 885 default n
1146 help 886 help
1147 Provides a cgroup controller for Hu 887 Provides a cgroup controller for HugeTLB pages.
1148 When you enable this, you can put a 888 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1149 The limit is enforced during page f 889 The limit is enforced during page fault. Since HugeTLB doesn't
1150 support page reclaim, enforcing the 890 support page reclaim, enforcing the limit at page fault time implies
1151 that, the application will get SIGB 891 that, the application will get SIGBUS signal if it tries to access
1152 HugeTLB pages beyond its limit. Thi 892 HugeTLB pages beyond its limit. This requires the application to know
1153 beforehand how much HugeTLB pages i 893 beforehand how much HugeTLB pages it would require for its use. The
1154 control group is tracked in the thi 894 control group is tracked in the third page lru pointer. This means
1155 that we cannot use the controller w 895 that we cannot use the controller with huge page less than 3 pages.
1156 896
1157 config CPUSETS 897 config CPUSETS
1158 bool "Cpuset controller" 898 bool "Cpuset controller"
1159 depends on SMP 899 depends on SMP
1160 help 900 help
1161 This option will let you create and 901 This option will let you create and manage CPUSETs which
1162 allow dynamically partitioning a sy 902 allow dynamically partitioning a system into sets of CPUs and
1163 Memory Nodes and assigning tasks to 903 Memory Nodes and assigning tasks to run only within those sets.
1164 This is primarily useful on large S 904 This is primarily useful on large SMP or NUMA systems.
1165 905
1166 Say N if unsure. 906 Say N if unsure.
1167 907
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 908 config PROC_PID_CPUSET
1182 bool "Include legacy /proc/<pid>/cpus 909 bool "Include legacy /proc/<pid>/cpuset file"
1183 depends on CPUSETS 910 depends on CPUSETS
1184 default y 911 default y
1185 912
1186 config CGROUP_DEVICE 913 config CGROUP_DEVICE
1187 bool "Device controller" 914 bool "Device controller"
1188 help 915 help
1189 Provides a cgroup controller implem 916 Provides a cgroup controller implementing whitelists for
1190 devices which a process in the cgro 917 devices which a process in the cgroup can mknod or open.
1191 918
1192 config CGROUP_CPUACCT 919 config CGROUP_CPUACCT
1193 bool "Simple CPU accounting controlle 920 bool "Simple CPU accounting controller"
1194 help 921 help
1195 Provides a simple controller for mo 922 Provides a simple controller for monitoring the
1196 total CPU consumed by the tasks in 923 total CPU consumed by the tasks in a cgroup.
1197 924
1198 config CGROUP_PERF 925 config CGROUP_PERF
1199 bool "Perf controller" 926 bool "Perf controller"
1200 depends on PERF_EVENTS 927 depends on PERF_EVENTS
1201 help 928 help
1202 This option extends the perf per-cp 929 This option extends the perf per-cpu mode to restrict monitoring
1203 to threads which belong to the cgro 930 to threads which belong to the cgroup specified and run on the
1204 designated cpu. Or this can be use !! 931 designated cpu.
1205 so that it can monitor performance <<
1206 932
1207 Say N if unsure. 933 Say N if unsure.
1208 934
1209 config CGROUP_BPF 935 config CGROUP_BPF
1210 bool "Support for eBPF programs attac 936 bool "Support for eBPF programs attached to cgroups"
1211 depends on BPF_SYSCALL 937 depends on BPF_SYSCALL
1212 select SOCK_CGROUP_DATA 938 select SOCK_CGROUP_DATA
1213 help 939 help
1214 Allow attaching eBPF programs to a 940 Allow attaching eBPF programs to a cgroup using the bpf(2)
1215 syscall command BPF_PROG_ATTACH. 941 syscall command BPF_PROG_ATTACH.
1216 942
1217 In which context these programs are 943 In which context these programs are accessed depends on the type
1218 of attachment. For instance, progra 944 of attachment. For instance, programs that are attached using
1219 BPF_CGROUP_INET_INGRESS will be exe 945 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
1220 inet sockets. 946 inet sockets.
1221 947
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 948 config CGROUP_DEBUG
1237 bool "Debug controller" 949 bool "Debug controller"
1238 default n 950 default n
1239 depends on DEBUG_KERNEL 951 depends on DEBUG_KERNEL
1240 help 952 help
1241 This option enables a simple contro 953 This option enables a simple controller that exports
1242 debugging information about the cgr 954 debugging information about the cgroups framework. This
1243 controller is for control cgroup de 955 controller is for control cgroup debugging only. Its
1244 interfaces are not stable. 956 interfaces are not stable.
1245 957
1246 Say N. 958 Say N.
1247 959
1248 config SOCK_CGROUP_DATA 960 config SOCK_CGROUP_DATA
1249 bool 961 bool
1250 default n 962 default n
1251 963
1252 endif # CGROUPS 964 endif # CGROUPS
1253 965
1254 menuconfig NAMESPACES 966 menuconfig NAMESPACES
1255 bool "Namespaces support" if EXPERT 967 bool "Namespaces support" if EXPERT
1256 depends on MULTIUSER 968 depends on MULTIUSER
1257 default !EXPERT 969 default !EXPERT
1258 help 970 help
1259 Provides the way to make tasks work 971 Provides the way to make tasks work with different objects using
1260 the same id. For example same IPC i 972 the same id. For example same IPC id may refer to different objects
1261 or same user id or pid may refer to 973 or same user id or pid may refer to different tasks when used in
1262 different namespaces. 974 different namespaces.
1263 975
1264 if NAMESPACES 976 if NAMESPACES
1265 977
1266 config UTS_NS 978 config UTS_NS
1267 bool "UTS namespace" 979 bool "UTS namespace"
1268 default y 980 default y
1269 help 981 help
1270 In this namespace tasks see differe 982 In this namespace tasks see different info provided with the
1271 uname() system call 983 uname() system call
1272 984
1273 config TIME_NS <<
1274 bool "TIME namespace" <<
1275 depends on GENERIC_VDSO_TIME_NS <<
1276 default y <<
1277 help <<
1278 In this namespace boottime and mono <<
1279 The time will keep going with the s <<
1280 <<
1281 config IPC_NS 985 config IPC_NS
1282 bool "IPC namespace" 986 bool "IPC namespace"
1283 depends on (SYSVIPC || POSIX_MQUEUE) 987 depends on (SYSVIPC || POSIX_MQUEUE)
1284 default y 988 default y
1285 help 989 help
1286 In this namespace tasks work with I 990 In this namespace tasks work with IPC ids which correspond to
1287 different IPC objects in different 991 different IPC objects in different namespaces.
1288 992
1289 config USER_NS 993 config USER_NS
1290 bool "User namespace" 994 bool "User namespace"
1291 default n 995 default n
1292 help 996 help
1293 This allows containers, i.e. vserve 997 This allows containers, i.e. vservers, to use user namespaces
1294 to provide different user info for 998 to provide different user info for different servers.
1295 999
1296 When user namespaces are enabled in 1000 When user namespaces are enabled in the kernel it is
1297 recommended that the MEMCG option a 1001 recommended that the MEMCG option also be enabled and that
1298 user-space use the memory control g 1002 user-space use the memory control groups to limit the amount
1299 of memory a memory unprivileged use 1003 of memory a memory unprivileged users can use.
1300 1004
1301 If unsure, say N. 1005 If unsure, say N.
1302 1006
1303 config PID_NS 1007 config PID_NS
1304 bool "PID Namespaces" 1008 bool "PID Namespaces"
1305 default y 1009 default y
1306 help 1010 help
1307 Support process id namespaces. Thi 1011 Support process id namespaces. This allows having multiple
1308 processes with the same pid as long 1012 processes with the same pid as long as they are in different
1309 pid namespaces. This is a building 1013 pid namespaces. This is a building block of containers.
1310 1014
1311 config NET_NS 1015 config NET_NS
1312 bool "Network namespace" 1016 bool "Network namespace"
1313 depends on NET 1017 depends on NET
1314 default y 1018 default y
1315 help 1019 help
1316 Allow user space to create what app 1020 Allow user space to create what appear to be multiple instances
1317 of the network stack. 1021 of the network stack.
1318 1022
1319 endif # NAMESPACES 1023 endif # NAMESPACES
1320 1024
1321 config CHECKPOINT_RESTORE 1025 config CHECKPOINT_RESTORE
1322 bool "Checkpoint/restore support" 1026 bool "Checkpoint/restore support"
1323 depends on PROC_FS <<
1324 select PROC_CHILDREN 1027 select PROC_CHILDREN
1325 select KCMP <<
1326 default n 1028 default n
1327 help 1029 help
1328 Enables additional kernel features 1030 Enables additional kernel features in a sake of checkpoint/restore.
1329 In particular it adds auxiliary prc 1031 In particular it adds auxiliary prctl codes to setup process text,
1330 data and heap segment sizes, and a 1032 data and heap segment sizes, and a few additional /proc filesystem
1331 entries. 1033 entries.
1332 1034
1333 If unsure, say N here. 1035 If unsure, say N here.
1334 1036
1335 config SCHED_AUTOGROUP 1037 config SCHED_AUTOGROUP
1336 bool "Automatic process group schedul 1038 bool "Automatic process group scheduling"
1337 select CGROUPS 1039 select CGROUPS
1338 select CGROUP_SCHED 1040 select CGROUP_SCHED
1339 select FAIR_GROUP_SCHED 1041 select FAIR_GROUP_SCHED
1340 help 1042 help
1341 This option optimizes the scheduler 1043 This option optimizes the scheduler for common desktop workloads by
1342 automatically creating and populati 1044 automatically creating and populating task groups. This separation
1343 of workloads isolates aggressive CP 1045 of workloads isolates aggressive CPU burners (like build jobs) from
1344 desktop applications. Task group a 1046 desktop applications. Task group autogeneration is currently based
1345 upon task session. 1047 upon task session.
1346 1048
>> 1049 config SYSFS_DEPRECATED
>> 1050 bool "Enable deprecated sysfs features to support old userspace tools"
>> 1051 depends on SYSFS
>> 1052 default n
>> 1053 help
>> 1054 This option adds code that switches the layout of the "block" class
>> 1055 devices, to not show up in /sys/class/block/, but only in
>> 1056 /sys/block/.
>> 1057
>> 1058 This switch is only active when the sysfs.deprecated=1 boot option is
>> 1059 passed or the SYSFS_DEPRECATED_V2 option is set.
>> 1060
>> 1061 This option allows new kernels to run on old distributions and tools,
>> 1062 which might get confused by /sys/class/block/. Since 2007/2008 all
>> 1063 major distributions and tools handle this just fine.
>> 1064
>> 1065 Recent distributions and userspace tools after 2009/2010 depend on
>> 1066 the existence of /sys/class/block/, and will not work with this
>> 1067 option enabled.
>> 1068
>> 1069 Only if you are using a new kernel on an old distribution, you might
>> 1070 need to say Y here.
>> 1071
>> 1072 config SYSFS_DEPRECATED_V2
>> 1073 bool "Enable deprecated sysfs features by default"
>> 1074 default n
>> 1075 depends on SYSFS
>> 1076 depends on SYSFS_DEPRECATED
>> 1077 help
>> 1078 Enable deprecated sysfs by default.
>> 1079
>> 1080 See the CONFIG_SYSFS_DEPRECATED option for more details about this
>> 1081 option.
>> 1082
>> 1083 Only if you are using a new kernel on an old distribution, you might
>> 1084 need to say Y here. Even then, odds are you would not need it
>> 1085 enabled, you can always pass the boot option if absolutely necessary.
>> 1086
1347 config RELAY 1087 config RELAY
1348 bool "Kernel->user space relay suppor 1088 bool "Kernel->user space relay support (formerly relayfs)"
1349 select IRQ_WORK 1089 select IRQ_WORK
1350 help 1090 help
1351 This option enables support for rel 1091 This option enables support for relay interface support in
1352 certain file systems (such as debug 1092 certain file systems (such as debugfs).
1353 It is designed to provide an effici 1093 It is designed to provide an efficient mechanism for tools and
1354 facilities to relay large amounts o 1094 facilities to relay large amounts of data from kernel space to
1355 user space. 1095 user space.
1356 1096
1357 If unsure, say N. 1097 If unsure, say N.
1358 1098
1359 config BLK_DEV_INITRD 1099 config BLK_DEV_INITRD
1360 bool "Initial RAM filesystem and RAM 1100 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1361 help 1101 help
1362 The initial RAM filesystem is a ram 1102 The initial RAM filesystem is a ramfs which is loaded by the
1363 boot loader (loadlin or lilo) and t 1103 boot loader (loadlin or lilo) and that is mounted as root
1364 before the normal boot procedure. I 1104 before the normal boot procedure. It is typically used to
1365 load modules needed to mount the "r 1105 load modules needed to mount the "real" root file system,
1366 etc. See <file:Documentation/admin- 1106 etc. See <file:Documentation/admin-guide/initrd.rst> for details.
1367 1107
1368 If RAM disk support (BLK_DEV_RAM) i 1108 If RAM disk support (BLK_DEV_RAM) is also included, this
1369 also enables initial RAM disk (init 1109 also enables initial RAM disk (initrd) support and adds
1370 15 Kbytes (more on some other archi 1110 15 Kbytes (more on some other architectures) to the kernel size.
1371 1111
1372 If unsure say Y. 1112 If unsure say Y.
1373 1113
1374 if BLK_DEV_INITRD 1114 if BLK_DEV_INITRD
1375 1115
1376 source "usr/Kconfig" 1116 source "usr/Kconfig"
1377 1117
1378 endif 1118 endif
1379 1119
1380 config BOOT_CONFIG <<
1381 bool "Boot config support" <<
1382 select BLK_DEV_INITRD if !BOOT_CONFIG <<
1383 help <<
1384 Extra boot config allows system adm <<
1385 complemental extension of kernel cm <<
1386 The boot config file must be attach <<
1387 with checksum, size and magic word. <<
1388 See <file:Documentation/admin-guide <<
1389 <<
1390 If unsure, say Y. <<
1391 <<
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 1120 choice
1435 prompt "Compiler optimization level" 1121 prompt "Compiler optimization level"
1436 default CC_OPTIMIZE_FOR_PERFORMANCE 1122 default CC_OPTIMIZE_FOR_PERFORMANCE
1437 1123
1438 config CC_OPTIMIZE_FOR_PERFORMANCE 1124 config CC_OPTIMIZE_FOR_PERFORMANCE
1439 bool "Optimize for performance (-O2)" !! 1125 bool "Optimize for performance"
1440 help 1126 help
1441 This is the default optimization le 1127 This is the default optimization level for the kernel, building
1442 with the "-O2" compiler flag for be 1128 with the "-O2" compiler flag for best performance and most
1443 helpful compile-time warnings. 1129 helpful compile-time warnings.
1444 1130
1445 config CC_OPTIMIZE_FOR_SIZE 1131 config CC_OPTIMIZE_FOR_SIZE
1446 bool "Optimize for size (-Os)" !! 1132 bool "Optimize for size"
>> 1133 imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED # avoid false positives
1447 help 1134 help
1448 Choosing this option will pass "-Os !! 1135 Enabling this option will pass "-Os" instead of "-O2" to
1449 in a smaller kernel. !! 1136 your compiler resulting in a smaller kernel.
>> 1137
>> 1138 If unsure, say N.
1450 1139
1451 endchoice 1140 endchoice
1452 1141
1453 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1142 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1454 bool 1143 bool
1455 help 1144 help
1456 This requires that the arch annotat 1145 This requires that the arch annotates or otherwise protects
1457 its external entry points from bein 1146 its external entry points from being discarded. Linker scripts
1458 must also merge .text.*, .data.*, a 1147 must also merge .text.*, .data.*, and .bss.* correctly into
1459 output sections. Care must be taken 1148 output sections. Care must be taken not to pull in unrelated
1460 sections (e.g., '.text.init'). Typi 1149 sections (e.g., '.text.init'). Typically '.' in section names
1461 is used to distinguish them from la 1150 is used to distinguish them from label names / C identifiers.
1462 1151
1463 config LD_DEAD_CODE_DATA_ELIMINATION 1152 config LD_DEAD_CODE_DATA_ELIMINATION
1464 bool "Dead code and data elimination 1153 bool "Dead code and data elimination (EXPERIMENTAL)"
1465 depends on HAVE_LD_DEAD_CODE_DATA_ELI 1154 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1466 depends on EXPERT 1155 depends on EXPERT
>> 1156 depends on !(FUNCTION_TRACER && CC_IS_GCC && GCC_VERSION < 40800)
1467 depends on $(cc-option,-ffunction-sec 1157 depends on $(cc-option,-ffunction-sections -fdata-sections)
1468 depends on $(ld-option,--gc-sections) 1158 depends on $(ld-option,--gc-sections)
1469 help 1159 help
1470 Enable this if you want to do dead 1160 Enable this if you want to do dead code and data elimination with
1471 the linker by compiling with -ffunc 1161 the linker by compiling with -ffunction-sections -fdata-sections,
1472 and linking with --gc-sections. 1162 and linking with --gc-sections.
1473 1163
1474 This can reduce on disk and in-memo 1164 This can reduce on disk and in-memory size of the kernel
1475 code and static data, particularly 1165 code and static data, particularly for small configs and
1476 on small systems. This has the poss 1166 on small systems. This has the possibility of introducing
1477 silently broken kernel if the requi 1167 silently broken kernel if the required annotations are not
1478 present. This option is not well te 1168 present. This option is not well tested yet, so use at your
1479 own risk. 1169 own risk.
1480 1170
1481 config LD_ORPHAN_WARN <<
1482 def_bool y <<
1483 depends on ARCH_WANT_LD_ORPHAN_WARN <<
1484 depends on $(ld-option,--orphan-handl <<
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 <<
1493 config SYSCTL 1171 config SYSCTL
1494 bool 1172 bool
1495 1173
>> 1174 config ANON_INODES
>> 1175 bool
>> 1176
1496 config HAVE_UID16 1177 config HAVE_UID16
1497 bool 1178 bool
1498 1179
1499 config SYSCTL_EXCEPTION_TRACE 1180 config SYSCTL_EXCEPTION_TRACE
1500 bool 1181 bool
1501 help 1182 help
1502 Enable support for /proc/sys/debug/ 1183 Enable support for /proc/sys/debug/exception-trace.
1503 1184
1504 config SYSCTL_ARCH_UNALIGN_NO_WARN 1185 config SYSCTL_ARCH_UNALIGN_NO_WARN
1505 bool 1186 bool
1506 help 1187 help
1507 Enable support for /proc/sys/kernel 1188 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1508 Allows arch to define/use @no_unali 1189 Allows arch to define/use @no_unaligned_warning to possibly warn
1509 about unaligned access emulation go 1190 about unaligned access emulation going on under the hood.
1510 1191
1511 config SYSCTL_ARCH_UNALIGN_ALLOW 1192 config SYSCTL_ARCH_UNALIGN_ALLOW
1512 bool 1193 bool
1513 help 1194 help
1514 Enable support for /proc/sys/kernel 1195 Enable support for /proc/sys/kernel/unaligned-trap
1515 Allows arches to define/use @unalig 1196 Allows arches to define/use @unaligned_enabled to runtime toggle
1516 the unaligned access emulation. 1197 the unaligned access emulation.
1517 see arch/parisc/kernel/unaligned.c 1198 see arch/parisc/kernel/unaligned.c for reference
1518 1199
1519 config HAVE_PCSPKR_PLATFORM 1200 config HAVE_PCSPKR_PLATFORM
1520 bool 1201 bool
1521 1202
>> 1203 # interpreter that classic socket filters depend on
>> 1204 config BPF
>> 1205 bool
>> 1206
1522 menuconfig EXPERT 1207 menuconfig EXPERT
1523 bool "Configure standard kernel featu 1208 bool "Configure standard kernel features (expert users)"
1524 # Unhide debug options, to make the o 1209 # Unhide debug options, to make the on-by-default options visible
1525 select DEBUG_KERNEL 1210 select DEBUG_KERNEL
1526 help 1211 help
1527 This option allows certain base ker 1212 This option allows certain base kernel options and settings
1528 to be disabled or tweaked. This is !! 1213 to be disabled or tweaked. This is for specialized
1529 environments which can tolerate a " !! 1214 environments which can tolerate a "non-standard" kernel.
1530 Only use this if you really know wh !! 1215 Only use this if you really know what you are doing.
1531 1216
1532 config UID16 1217 config UID16
1533 bool "Enable 16-bit UID system calls" 1218 bool "Enable 16-bit UID system calls" if EXPERT
1534 depends on HAVE_UID16 && MULTIUSER 1219 depends on HAVE_UID16 && MULTIUSER
1535 default y 1220 default y
1536 help 1221 help
1537 This enables the legacy 16-bit UID 1222 This enables the legacy 16-bit UID syscall wrappers.
1538 1223
1539 config MULTIUSER 1224 config MULTIUSER
1540 bool "Multiple users, groups and capa 1225 bool "Multiple users, groups and capabilities support" if EXPERT
1541 default y 1226 default y
1542 help 1227 help
1543 This option enables support for non 1228 This option enables support for non-root users, groups and
1544 capabilities. 1229 capabilities.
1545 1230
1546 If you say N here, all processes wi 1231 If you say N here, all processes will run with UID 0, GID 0, and all
1547 possible capabilities. Saying N he 1232 possible capabilities. Saying N here also compiles out support for
1548 system calls related to UIDs, GIDs, 1233 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1549 setgid, and capset. 1234 setgid, and capset.
1550 1235
1551 If unsure, say Y here. 1236 If unsure, say Y here.
1552 1237
1553 config SGETMASK_SYSCALL 1238 config SGETMASK_SYSCALL
1554 bool "sgetmask/ssetmask syscalls supp 1239 bool "sgetmask/ssetmask syscalls support" if EXPERT
1555 default PARISC || M68K || PPC || MIPS !! 1240 def_bool PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH
1556 help !! 1241 ---help---
1557 sys_sgetmask and sys_ssetmask are o 1242 sys_sgetmask and sys_ssetmask are obsolete system calls
1558 no longer supported in libc but sti 1243 no longer supported in libc but still enabled by default in some
1559 architectures. 1244 architectures.
1560 1245
1561 If unsure, leave the default option 1246 If unsure, leave the default option here.
1562 1247
1563 config SYSFS_SYSCALL 1248 config SYSFS_SYSCALL
1564 bool "Sysfs syscall support" if EXPER 1249 bool "Sysfs syscall support" if EXPERT
1565 default y 1250 default y
1566 help !! 1251 ---help---
1567 sys_sysfs is an obsolete system cal 1252 sys_sysfs is an obsolete system call no longer supported in libc.
1568 Note that disabling this option is 1253 Note that disabling this option is more secure but might break
1569 compatibility with some systems. 1254 compatibility with some systems.
1570 1255
1571 If unsure say Y here. 1256 If unsure say Y here.
1572 1257
>> 1258 config SYSCTL_SYSCALL
>> 1259 bool "Sysctl syscall support" if EXPERT
>> 1260 depends on PROC_SYSCTL
>> 1261 default n
>> 1262 select SYSCTL
>> 1263 ---help---
>> 1264 sys_sysctl uses binary paths that have been found challenging
>> 1265 to properly maintain and use. The interface in /proc/sys
>> 1266 using paths with ascii names is now the primary path to this
>> 1267 information.
>> 1268
>> 1269 Almost nothing using the binary sysctl interface so if you are
>> 1270 trying to save some space it is probably safe to disable this,
>> 1271 making your kernel marginally smaller.
>> 1272
>> 1273 If unsure say N here.
>> 1274
1573 config FHANDLE 1275 config FHANDLE
1574 bool "open by fhandle syscalls" if EX 1276 bool "open by fhandle syscalls" if EXPERT
1575 select EXPORTFS 1277 select EXPORTFS
1576 default y 1278 default y
1577 help 1279 help
1578 If you say Y here, a user level pro 1280 If you say Y here, a user level program will be able to map
1579 file names to handle and then later 1281 file names to handle and then later use the handle for
1580 different file system operations. T 1282 different file system operations. This is useful in implementing
1581 userspace file servers, which now t 1283 userspace file servers, which now track files using handles instead
1582 of names. The handle would remain t 1284 of names. The handle would remain the same even if file names
1583 get renamed. Enables open_by_handle 1285 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
1584 syscalls. 1286 syscalls.
1585 1287
1586 config POSIX_TIMERS 1288 config POSIX_TIMERS
1587 bool "Posix Clocks & timers" if EXPER 1289 bool "Posix Clocks & timers" if EXPERT
1588 default y 1290 default y
1589 help 1291 help
1590 This includes native support for PO 1292 This includes native support for POSIX timers to the kernel.
1591 Some embedded systems have no use f 1293 Some embedded systems have no use for them and therefore they
1592 can be configured out to reduce the 1294 can be configured out to reduce the size of the kernel image.
1593 1295
1594 When this option is disabled, the f 1296 When this option is disabled, the following syscalls won't be
1595 available: timer_create, timer_gett 1297 available: timer_create, timer_gettime: timer_getoverrun,
1596 timer_settime, timer_delete, clock_ 1298 timer_settime, timer_delete, clock_adjtime, getitimer,
1597 setitimer, alarm. Furthermore, the 1299 setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
1598 clock_getres and clock_nanosleep sy 1300 clock_getres and clock_nanosleep syscalls will be limited to
1599 CLOCK_REALTIME, CLOCK_MONOTONIC and 1301 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
1600 1302
1601 If unsure say y. 1303 If unsure say y.
1602 1304
1603 config PRINTK 1305 config PRINTK
1604 default y 1306 default y
1605 bool "Enable support for printk" if E 1307 bool "Enable support for printk" if EXPERT
1606 select IRQ_WORK 1308 select IRQ_WORK
1607 help 1309 help
1608 This option enables normal printk s 1310 This option enables normal printk support. Removing it
1609 eliminates most of the message stri 1311 eliminates most of the message strings from the kernel image
1610 and makes the kernel more or less s 1312 and makes the kernel more or less silent. As this makes it
1611 very difficult to diagnose system p 1313 very difficult to diagnose system problems, saying N here is
1612 strongly discouraged. 1314 strongly discouraged.
1613 1315
>> 1316 config PRINTK_NMI
>> 1317 def_bool y
>> 1318 depends on PRINTK
>> 1319 depends on HAVE_NMI
>> 1320
1614 config BUG 1321 config BUG
1615 bool "BUG() support" if EXPERT 1322 bool "BUG() support" if EXPERT
1616 default y 1323 default y
1617 help 1324 help
1618 Disabling this option eliminates su !! 1325 Disabling this option eliminates support for BUG and WARN, reducing
1619 the size of your kernel image and p !! 1326 the size of your kernel image and potentially quietly ignoring
1620 numerous fatal conditions. You shou !! 1327 numerous fatal conditions. You should only consider disabling this
1621 option for embedded systems with no !! 1328 option for embedded systems with no facilities for reporting errors.
1622 Just say Y. !! 1329 Just say Y.
1623 1330
1624 config ELF_CORE 1331 config ELF_CORE
1625 depends on COREDUMP 1332 depends on COREDUMP
1626 default y 1333 default y
1627 bool "Enable ELF core dumps" if EXPER 1334 bool "Enable ELF core dumps" if EXPERT
1628 help 1335 help
1629 Enable support for generating core 1336 Enable support for generating core dumps. Disabling saves about 4k.
1630 1337
1631 1338
1632 config PCSPKR_PLATFORM 1339 config PCSPKR_PLATFORM
1633 bool "Enable PC-Speaker support" if E 1340 bool "Enable PC-Speaker support" if EXPERT
1634 depends on HAVE_PCSPKR_PLATFORM 1341 depends on HAVE_PCSPKR_PLATFORM
1635 select I8253_LOCK 1342 select I8253_LOCK
1636 default y 1343 default y
1637 help 1344 help
1638 This option allows to disable the i !! 1345 This option allows to disable the internal PC-Speaker
1639 support, saving some memory. !! 1346 support, saving some memory.
1640 1347
1641 config BASE_SMALL !! 1348 config BASE_FULL
1642 bool "Enable smaller-sized data struc !! 1349 default y
>> 1350 bool "Enable full-sized data structures for core" if EXPERT
1643 help 1351 help
1644 Enabling this option reduces the si !! 1352 Disabling this option reduces the size of miscellaneous core
1645 kernel data structures. This saves 1353 kernel data structures. This saves memory on small machines,
1646 but may reduce performance. 1354 but may reduce performance.
1647 1355
1648 config FUTEX 1356 config FUTEX
1649 bool "Enable futex support" if EXPERT 1357 bool "Enable futex support" if EXPERT
1650 depends on !(SPARC32 && SMP) <<
1651 default y 1358 default y
1652 imply RT_MUTEXES 1359 imply RT_MUTEXES
1653 help 1360 help
1654 Disabling this option will cause th 1361 Disabling this option will cause the kernel to be built without
1655 support for "fast userspace mutexes 1362 support for "fast userspace mutexes". The resulting kernel may not
1656 run glibc-based applications correc 1363 run glibc-based applications correctly.
1657 1364
1658 config FUTEX_PI 1365 config FUTEX_PI
1659 bool 1366 bool
1660 depends on FUTEX && RT_MUTEXES 1367 depends on FUTEX && RT_MUTEXES
1661 default y 1368 default y
1662 1369
>> 1370 config HAVE_FUTEX_CMPXCHG
>> 1371 bool
>> 1372 depends on FUTEX
>> 1373 help
>> 1374 Architectures should select this if futex_atomic_cmpxchg_inatomic()
>> 1375 is implemented and always working. This removes a couple of runtime
>> 1376 checks.
>> 1377
1663 config EPOLL 1378 config EPOLL
1664 bool "Enable eventpoll support" if EX 1379 bool "Enable eventpoll support" if EXPERT
1665 default y 1380 default y
>> 1381 select ANON_INODES
1666 help 1382 help
1667 Disabling this option will cause th 1383 Disabling this option will cause the kernel to be built without
1668 support for epoll family of system 1384 support for epoll family of system calls.
1669 1385
1670 config SIGNALFD 1386 config SIGNALFD
1671 bool "Enable signalfd() system call" 1387 bool "Enable signalfd() system call" if EXPERT
>> 1388 select ANON_INODES
1672 default y 1389 default y
1673 help 1390 help
1674 Enable the signalfd() system call t 1391 Enable the signalfd() system call that allows to receive signals
1675 on a file descriptor. 1392 on a file descriptor.
1676 1393
1677 If unsure, say Y. 1394 If unsure, say Y.
1678 1395
1679 config TIMERFD 1396 config TIMERFD
1680 bool "Enable timerfd() system call" i 1397 bool "Enable timerfd() system call" if EXPERT
>> 1398 select ANON_INODES
1681 default y 1399 default y
1682 help 1400 help
1683 Enable the timerfd() system call th 1401 Enable the timerfd() system call that allows to receive timer
1684 events on a file descriptor. 1402 events on a file descriptor.
1685 1403
1686 If unsure, say Y. 1404 If unsure, say Y.
1687 1405
1688 config EVENTFD 1406 config EVENTFD
1689 bool "Enable eventfd() system call" i 1407 bool "Enable eventfd() system call" if EXPERT
>> 1408 select ANON_INODES
1690 default y 1409 default y
1691 help 1410 help
1692 Enable the eventfd() system call th 1411 Enable the eventfd() system call that allows to receive both
1693 kernel notification (ie. KAIO) or u 1412 kernel notification (ie. KAIO) or userspace notifications.
1694 1413
1695 If unsure, say Y. 1414 If unsure, say Y.
1696 1415
1697 config SHMEM 1416 config SHMEM
1698 bool "Use full shmem filesystem" if E 1417 bool "Use full shmem filesystem" if EXPERT
1699 default y 1418 default y
1700 depends on MMU 1419 depends on MMU
1701 help 1420 help
1702 The shmem is an internal filesystem 1421 The shmem is an internal filesystem used to manage shared memory.
1703 It is backed by swap and manages re 1422 It is backed by swap and manages resource limits. It is also exported
1704 to userspace as tmpfs if TMPFS is e 1423 to userspace as tmpfs if TMPFS is enabled. Disabling this
1705 option replaces shmem and tmpfs wit 1424 option replaces shmem and tmpfs with the much simpler ramfs code,
1706 which may be appropriate on small s 1425 which may be appropriate on small systems without swap.
1707 1426
1708 config AIO 1427 config AIO
1709 bool "Enable AIO support" if EXPERT 1428 bool "Enable AIO support" if EXPERT
1710 default y 1429 default y
1711 help 1430 help
1712 This option enables POSIX asynchron 1431 This option enables POSIX asynchronous I/O which may by used
1713 by some high performance threaded a 1432 by some high performance threaded applications. Disabling
1714 this option saves about 7k. 1433 this option saves about 7k.
1715 1434
1716 config IO_URING 1435 config IO_URING
1717 bool "Enable IO uring support" if EXP 1436 bool "Enable IO uring support" if EXPERT
1718 select IO_WQ !! 1437 select ANON_INODES
1719 default y 1438 default y
1720 help 1439 help
1721 This option enables support for the 1440 This option enables support for the io_uring interface, enabling
1722 applications to submit and complete 1441 applications to submit and complete IO through submission and
1723 completion rings that are shared be 1442 completion rings that are shared between the kernel and application.
1724 1443
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 1444 config ADVISE_SYSCALLS
1739 bool "Enable madvise/fadvise syscalls 1445 bool "Enable madvise/fadvise syscalls" if EXPERT
1740 default y 1446 default y
1741 help 1447 help
1742 This option enables the madvise and 1448 This option enables the madvise and fadvise syscalls, used by
1743 applications to advise the kernel a 1449 applications to advise the kernel about their future memory or file
1744 usage, improving performance. If bu 1450 usage, improving performance. If building an embedded system where no
1745 applications use these syscalls, yo 1451 applications use these syscalls, you can disable this option to save
1746 space. 1452 space.
1747 1453
1748 config MEMBARRIER 1454 config MEMBARRIER
1749 bool "Enable membarrier() system call 1455 bool "Enable membarrier() system call" if EXPERT
1750 default y 1456 default y
1751 help 1457 help
1752 Enable the membarrier() system call 1458 Enable the membarrier() system call that allows issuing memory
1753 barriers across all running threads 1459 barriers across all running threads, which can be used to distribute
1754 the cost of user-space memory barri 1460 the cost of user-space memory barriers asymmetrically by transforming
1755 pairs of memory barriers into pairs 1461 pairs of memory barriers into pairs consisting of membarrier() and a
1756 compiler barrier. 1462 compiler barrier.
1757 1463
1758 If unsure, say Y. 1464 If unsure, say Y.
1759 1465
1760 config KCMP !! 1466 config KALLSYMS
1761 bool "Enable kcmp() system call" if E !! 1467 bool "Load all symbols for debugging/ksymoops" if EXPERT
>> 1468 default y
>> 1469 help
>> 1470 Say Y here to let the kernel print out symbolic crash information and
>> 1471 symbolic stack backtraces. This increases the size of the kernel
>> 1472 somewhat, as all symbols have to be loaded into the kernel image.
>> 1473
>> 1474 config KALLSYMS_ALL
>> 1475 bool "Include all symbols in kallsyms"
>> 1476 depends on DEBUG_KERNEL && KALLSYMS
1762 help 1477 help
1763 Enable the kernel resource comparis !! 1478 Normally kallsyms only contains the symbols of functions for nicer
1764 user-space with the ability to comp !! 1479 OOPS messages and backtraces (i.e., symbols from the text and inittext
1765 share a common resource, such as a !! 1480 sections). This is sufficient for most cases. And only in very rare
1766 memory space. !! 1481 cases (e.g., when a debugger is used) all symbols are required (e.g.,
>> 1482 names of variables from the data sections, etc).
>> 1483
>> 1484 This option makes sure that all symbols are loaded into the kernel
>> 1485 image (i.e., symbols from all sections) in cost of increased kernel
>> 1486 size (depending on the kernel configuration, it may be 300KiB or
>> 1487 something like this).
1767 1488
1768 If unsure, say N. !! 1489 Say N unless you really need all symbols.
>> 1490
>> 1491 config KALLSYMS_ABSOLUTE_PERCPU
>> 1492 bool
>> 1493 depends on KALLSYMS
>> 1494 default X86_64 && SMP
>> 1495
>> 1496 config KALLSYMS_BASE_RELATIVE
>> 1497 bool
>> 1498 depends on KALLSYMS
>> 1499 default !IA64
>> 1500 help
>> 1501 Instead of emitting them as absolute values in the native word size,
>> 1502 emit the symbol references in the kallsyms table as 32-bit entries,
>> 1503 each containing a relative value in the range [base, base + U32_MAX]
>> 1504 or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either
>> 1505 an absolute value in the range [0, S32_MAX] or a relative value in the
>> 1506 range [base, base + S32_MAX], where base is the lowest relative symbol
>> 1507 address encountered in the image.
>> 1508
>> 1509 On 64-bit builds, this reduces the size of the address table by 50%,
>> 1510 but more importantly, it results in entries whose values are build
>> 1511 time constants, and no relocation pass is required at runtime to fix
>> 1512 up the entries based on the runtime load address of the kernel.
>> 1513
>> 1514 # end of the "standard kernel features (expert users)" menu
>> 1515
>> 1516 # syscall, maps, verifier
>> 1517 config BPF_SYSCALL
>> 1518 bool "Enable bpf() system call"
>> 1519 select ANON_INODES
>> 1520 select BPF
>> 1521 select IRQ_WORK
>> 1522 default n
>> 1523 help
>> 1524 Enable the bpf() system call that allows to manipulate eBPF
>> 1525 programs and maps via file descriptors.
>> 1526
>> 1527 config BPF_JIT_ALWAYS_ON
>> 1528 bool "Permanently enable BPF JIT and remove BPF interpreter"
>> 1529 depends on BPF_SYSCALL && HAVE_EBPF_JIT && BPF_JIT
>> 1530 help
>> 1531 Enables BPF JIT and removes BPF interpreter to avoid
>> 1532 speculative execution of BPF instructions by the interpreter
>> 1533
>> 1534 config USERFAULTFD
>> 1535 bool "Enable userfaultfd() system call"
>> 1536 select ANON_INODES
>> 1537 depends on MMU
>> 1538 help
>> 1539 Enable the userfaultfd() system call that allows to intercept and
>> 1540 handle page faults in userland.
>> 1541
>> 1542 config ARCH_HAS_MEMBARRIER_CALLBACKS
>> 1543 bool
>> 1544
>> 1545 config ARCH_HAS_MEMBARRIER_SYNC_CORE
>> 1546 bool
1769 1547
1770 config RSEQ 1548 config RSEQ
1771 bool "Enable rseq() system call" if E 1549 bool "Enable rseq() system call" if EXPERT
1772 default y 1550 default y
1773 depends on HAVE_RSEQ 1551 depends on HAVE_RSEQ
1774 select MEMBARRIER 1552 select MEMBARRIER
1775 help 1553 help
1776 Enable the restartable sequences sy 1554 Enable the restartable sequences system call. It provides a
1777 user-space cache for the current CP 1555 user-space cache for the current CPU number value, which
1778 speeds up getting the current CPU n 1556 speeds up getting the current CPU number from user-space,
1779 as well as an ABI to speed up user- 1557 as well as an ABI to speed up user-space operations on
1780 per-CPU data. 1558 per-CPU data.
1781 1559
1782 If unsure, say Y. 1560 If unsure, say Y.
1783 1561
1784 config DEBUG_RSEQ 1562 config DEBUG_RSEQ
1785 default n 1563 default n
1786 bool "Enable debugging of rseq() syst !! 1564 bool "Enabled debugging of rseq() system call" if EXPERT
1787 depends on RSEQ && DEBUG_KERNEL 1565 depends on RSEQ && DEBUG_KERNEL
1788 help 1566 help
1789 Enable extra debugging checks for t 1567 Enable extra debugging checks for the rseq system call.
1790 1568
1791 If unsure, say N. 1569 If unsure, say N.
1792 1570
1793 config CACHESTAT_SYSCALL !! 1571 config EMBEDDED
1794 bool "Enable cachestat() system call" !! 1572 bool "Embedded system"
1795 default y !! 1573 option allnoconfig_y
1796 help !! 1574 select EXPERT
1797 Enable the cachestat system call, w !! 1575 help
1798 statistics of a file (number of cac !! 1576 This option should be enabled if compiling the kernel for
1799 pages marked for writeback, (recent !! 1577 an embedded system so certain expert options are available
1800 !! 1578 for configuration.
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 <<
1811 bool "Load all symbols for debugging/ <<
1812 default y <<
1813 help <<
1814 Say Y here to let the kernel print <<
1815 symbolic stack backtraces. This inc <<
1816 somewhat, as all symbols have to be <<
1817 <<
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 <<
1832 bool "Include all symbols in kallsyms <<
1833 depends on DEBUG_KERNEL && KALLSYMS <<
1834 help <<
1835 Normally kallsyms only contains the <<
1836 OOPS messages and backtraces (i.e., <<
1837 sections). This is sufficient for m <<
1838 enable kernel live patching, or oth <<
1839 when a debugger is used) all symbol <<
1840 variables from the data sections, e <<
1841 <<
1842 This option makes sure that all sym <<
1843 image (i.e., symbols from all secti <<
1844 size (depending on the kernel confi <<
1845 something like this). <<
1846 <<
1847 Say N unless you really need all sy <<
1848 <<
1849 config KALLSYMS_ABSOLUTE_PERCPU <<
1850 bool <<
1851 depends on KALLSYMS <<
1852 default X86_64 && SMP <<
1853 <<
1854 # end of the "standard kernel features (exper <<
1855 <<
1856 config ARCH_HAS_MEMBARRIER_CALLBACKS <<
1857 bool <<
1858 <<
1859 config ARCH_HAS_MEMBARRIER_SYNC_CORE <<
1860 bool <<
1861 1579
1862 config HAVE_PERF_EVENTS 1580 config HAVE_PERF_EVENTS
1863 bool 1581 bool
1864 help 1582 help
1865 See tools/perf/design.txt for detai 1583 See tools/perf/design.txt for details.
1866 1584
1867 config GUEST_PERF_EVENTS <<
1868 bool <<
1869 depends on HAVE_PERF_EVENTS <<
1870 <<
1871 config PERF_USE_VMALLOC 1585 config PERF_USE_VMALLOC
1872 bool 1586 bool
1873 help 1587 help
1874 See tools/perf/design.txt for detai 1588 See tools/perf/design.txt for details
1875 1589
>> 1590 config PC104
>> 1591 bool "PC/104 support" if EXPERT
>> 1592 help
>> 1593 Expose PC/104 form factor device drivers and options available for
>> 1594 selection and configuration. Enable this option if your target
>> 1595 machine has a PC/104 bus.
>> 1596
1876 menu "Kernel Performance Events And Counters" 1597 menu "Kernel Performance Events And Counters"
1877 1598
1878 config PERF_EVENTS 1599 config PERF_EVENTS
1879 bool "Kernel performance events and c 1600 bool "Kernel performance events and counters"
1880 default y if PROFILING 1601 default y if PROFILING
1881 depends on HAVE_PERF_EVENTS 1602 depends on HAVE_PERF_EVENTS
>> 1603 select ANON_INODES
1882 select IRQ_WORK 1604 select IRQ_WORK
>> 1605 select SRCU
1883 help 1606 help
1884 Enable kernel support for various p 1607 Enable kernel support for various performance events provided
1885 by software and hardware. 1608 by software and hardware.
1886 1609
1887 Software events are supported eithe 1610 Software events are supported either built-in or via the
1888 use of generic tracepoints. 1611 use of generic tracepoints.
1889 1612
1890 Most modern CPUs support performanc 1613 Most modern CPUs support performance events via performance
1891 counter registers. These registers 1614 counter registers. These registers count the number of certain
1892 types of hw events: such as instruc 1615 types of hw events: such as instructions executed, cachemisses
1893 suffered, or branches mis-predicted 1616 suffered, or branches mis-predicted - without slowing down the
1894 kernel or applications. These regis 1617 kernel or applications. These registers can also trigger interrupts
1895 when a threshold number of events h 1618 when a threshold number of events have passed - and can thus be
1896 used to profile the code that runs 1619 used to profile the code that runs on that CPU.
1897 1620
1898 The Linux Performance Event subsyst 1621 The Linux Performance Event subsystem provides an abstraction of
1899 these software and hardware event c 1622 these software and hardware event capabilities, available via a
1900 system call and used by the "perf" 1623 system call and used by the "perf" utility in tools/perf/. It
1901 provides per task and per CPU count 1624 provides per task and per CPU counters, and it provides event
1902 capabilities on top of those. 1625 capabilities on top of those.
1903 1626
1904 Say Y if unsure. 1627 Say Y if unsure.
1905 1628
1906 config DEBUG_PERF_USE_VMALLOC 1629 config DEBUG_PERF_USE_VMALLOC
1907 default n 1630 default n
1908 bool "Debug: use vmalloc to back perf 1631 bool "Debug: use vmalloc to back perf mmap() buffers"
1909 depends on PERF_EVENTS && DEBUG_KERNE 1632 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
1910 select PERF_USE_VMALLOC 1633 select PERF_USE_VMALLOC
1911 help 1634 help
1912 Use vmalloc memory to back perf mma !! 1635 Use vmalloc memory to back perf mmap() buffers.
1913 1636
1914 Mostly useful for debugging the vma !! 1637 Mostly useful for debugging the vmalloc code on platforms
1915 that don't require it. !! 1638 that don't require it.
1916 1639
1917 Say N if unsure. !! 1640 Say N if unsure.
1918 1641
1919 endmenu 1642 endmenu
1920 1643
>> 1644 config VM_EVENT_COUNTERS
>> 1645 default y
>> 1646 bool "Enable VM event counters for /proc/vmstat" if EXPERT
>> 1647 help
>> 1648 VM event counters are needed for event counts to be shown.
>> 1649 This option allows the disabling of the VM event counters
>> 1650 on EXPERT systems. /proc/vmstat will only show page counts
>> 1651 if VM event counters are disabled.
>> 1652
>> 1653 config SLUB_DEBUG
>> 1654 default y
>> 1655 bool "Enable SLUB debugging support" if EXPERT
>> 1656 depends on SLUB && SYSFS
>> 1657 help
>> 1658 SLUB has extensive debug support features. Disabling these can
>> 1659 result in significant savings in code size. This also disables
>> 1660 SLUB sysfs support. /sys/slab will not exist and there will be
>> 1661 no support for cache validation etc.
>> 1662
>> 1663 config SLUB_MEMCG_SYSFS_ON
>> 1664 default n
>> 1665 bool "Enable memcg SLUB sysfs support by default" if EXPERT
>> 1666 depends on SLUB && SYSFS && MEMCG
>> 1667 help
>> 1668 SLUB creates a directory under /sys/kernel/slab for each
>> 1669 allocation cache to host info and debug files. If memory
>> 1670 cgroup is enabled, each cache can have per memory cgroup
>> 1671 caches. SLUB can create the same sysfs directories for these
>> 1672 caches under /sys/kernel/slab/CACHE/cgroup but it can lead
>> 1673 to a very high number of debug files being created. This is
>> 1674 controlled by slub_memcg_sysfs boot parameter and this
>> 1675 config option determines the parameter's default value.
>> 1676
>> 1677 config COMPAT_BRK
>> 1678 bool "Disable heap randomization"
>> 1679 default y
>> 1680 help
>> 1681 Randomizing heap placement makes heap exploits harder, but it
>> 1682 also breaks ancient binaries (including anything libc5 based).
>> 1683 This option changes the bootup default to heap randomization
>> 1684 disabled, and can be overridden at runtime by setting
>> 1685 /proc/sys/kernel/randomize_va_space to 2.
>> 1686
>> 1687 On non-ancient distros (post-2000 ones) N is usually a safe choice.
>> 1688
>> 1689 choice
>> 1690 prompt "Choose SLAB allocator"
>> 1691 default SLUB
>> 1692 help
>> 1693 This option allows to select a slab allocator.
>> 1694
>> 1695 config SLAB
>> 1696 bool "SLAB"
>> 1697 select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 1698 help
>> 1699 The regular slab allocator that is established and known to work
>> 1700 well in all environments. It organizes cache hot objects in
>> 1701 per cpu and per node queues.
>> 1702
>> 1703 config SLUB
>> 1704 bool "SLUB (Unqueued Allocator)"
>> 1705 select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 1706 help
>> 1707 SLUB is a slab allocator that minimizes cache line usage
>> 1708 instead of managing queues of cached objects (SLAB approach).
>> 1709 Per cpu caching is realized using slabs of objects instead
>> 1710 of queues of objects. SLUB can use memory efficiently
>> 1711 and has enhanced diagnostics. SLUB is the default choice for
>> 1712 a slab allocator.
>> 1713
>> 1714 config SLOB
>> 1715 depends on EXPERT
>> 1716 bool "SLOB (Simple Allocator)"
>> 1717 help
>> 1718 SLOB replaces the stock allocator with a drastically simpler
>> 1719 allocator. SLOB is generally more space efficient but
>> 1720 does not perform as well on large systems.
>> 1721
>> 1722 endchoice
>> 1723
>> 1724 config SLAB_MERGE_DEFAULT
>> 1725 bool "Allow slab caches to be merged"
>> 1726 default y
>> 1727 help
>> 1728 For reduced kernel memory fragmentation, slab caches can be
>> 1729 merged when they share the same size and other characteristics.
>> 1730 This carries a risk of kernel heap overflows being able to
>> 1731 overwrite objects from merged caches (and more easily control
>> 1732 cache layout), which makes such heap attacks easier to exploit
>> 1733 by attackers. By keeping caches unmerged, these kinds of exploits
>> 1734 can usually only damage objects in the same cache. To disable
>> 1735 merging at runtime, "slab_nomerge" can be passed on the kernel
>> 1736 command line.
>> 1737
>> 1738 config SLAB_FREELIST_RANDOM
>> 1739 default n
>> 1740 depends on SLAB || SLUB
>> 1741 bool "SLAB freelist randomization"
>> 1742 help
>> 1743 Randomizes the freelist order used on creating new pages. This
>> 1744 security feature reduces the predictability of the kernel slab
>> 1745 allocator against heap overflows.
>> 1746
>> 1747 config SLAB_FREELIST_HARDENED
>> 1748 bool "Harden slab freelist metadata"
>> 1749 depends on SLUB
>> 1750 help
>> 1751 Many kernel heap attacks try to target slab cache metadata and
>> 1752 other infrastructure. This options makes minor performance
>> 1753 sacrifies to harden the kernel slab allocator against common
>> 1754 freelist exploit methods.
>> 1755
>> 1756 config SLUB_CPU_PARTIAL
>> 1757 default y
>> 1758 depends on SLUB && SMP
>> 1759 bool "SLUB per cpu partial cache"
>> 1760 help
>> 1761 Per cpu partial caches accellerate objects allocation and freeing
>> 1762 that is local to a processor at the price of more indeterminism
>> 1763 in the latency of the free. On overflow these caches will be cleared
>> 1764 which requires the taking of locks that may cause latency spikes.
>> 1765 Typically one would choose no for a realtime system.
>> 1766
>> 1767 config MMAP_ALLOW_UNINITIALIZED
>> 1768 bool "Allow mmapped anonymous memory to be uninitialized"
>> 1769 depends on EXPERT && !MMU
>> 1770 default n
>> 1771 help
>> 1772 Normally, and according to the Linux spec, anonymous memory obtained
>> 1773 from mmap() has its contents cleared before it is passed to
>> 1774 userspace. Enabling this config option allows you to request that
>> 1775 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
>> 1776 providing a huge performance boost. If this option is not enabled,
>> 1777 then the flag will be ignored.
>> 1778
>> 1779 This is taken advantage of by uClibc's malloc(), and also by
>> 1780 ELF-FDPIC binfmt's brk and stack allocator.
>> 1781
>> 1782 Because of the obvious security issues, this option should only be
>> 1783 enabled on embedded devices where you control what is run in
>> 1784 userspace. Since that isn't generally a problem on no-MMU systems,
>> 1785 it is normally safe to say Y here.
>> 1786
>> 1787 See Documentation/nommu-mmap.txt for more information.
>> 1788
1921 config SYSTEM_DATA_VERIFICATION 1789 config SYSTEM_DATA_VERIFICATION
1922 def_bool n 1790 def_bool n
1923 select SYSTEM_TRUSTED_KEYRING 1791 select SYSTEM_TRUSTED_KEYRING
1924 select KEYS 1792 select KEYS
1925 select CRYPTO 1793 select CRYPTO
1926 select CRYPTO_RSA 1794 select CRYPTO_RSA
1927 select ASYMMETRIC_KEY_TYPE 1795 select ASYMMETRIC_KEY_TYPE
1928 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 1796 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1929 select ASN1 1797 select ASN1
1930 select OID_REGISTRY 1798 select OID_REGISTRY
1931 select X509_CERTIFICATE_PARSER 1799 select X509_CERTIFICATE_PARSER
1932 select PKCS7_MESSAGE_PARSER 1800 select PKCS7_MESSAGE_PARSER
1933 help 1801 help
1934 Provide PKCS#7 message verification 1802 Provide PKCS#7 message verification using the contents of the system
1935 trusted keyring to provide public k 1803 trusted keyring to provide public keys. This then can be used for
1936 module verification, kexec image ve 1804 module verification, kexec image verification and firmware blob
1937 verification. 1805 verification.
1938 1806
1939 config PROFILING 1807 config PROFILING
1940 bool "Profiling support" 1808 bool "Profiling support"
1941 help 1809 help
1942 Say Y here to enable the extended p 1810 Say Y here to enable the extended profiling support mechanisms used
1943 by profilers. !! 1811 by profilers such as OProfile.
1944 <<
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 1812
1986 # 1813 #
1987 # Place an empty function call at each tracep 1814 # Place an empty function call at each tracepoint site. Can be
1988 # dynamically changed for a probe function. 1815 # dynamically changed for a probe function.
1989 # 1816 #
1990 config TRACEPOINTS 1817 config TRACEPOINTS
1991 bool 1818 bool
1992 1819
1993 source "kernel/Kconfig.kexec" <<
1994 <<
1995 endmenu # General setup 1820 endmenu # General setup
1996 1821
1997 source "arch/Kconfig" 1822 source "arch/Kconfig"
1998 1823
1999 config RT_MUTEXES 1824 config RT_MUTEXES
2000 bool 1825 bool
2001 default y if PREEMPT_RT <<
2002 1826
2003 config MODULE_SIG_FORMAT !! 1827 config BASE_SMALL
2004 def_bool n !! 1828 int
>> 1829 default 0 if BASE_FULL
>> 1830 default 1 if !BASE_FULL
>> 1831
>> 1832 menuconfig MODULES
>> 1833 bool "Enable loadable module support"
>> 1834 option modules
>> 1835 help
>> 1836 Kernel modules are small pieces of compiled code which can
>> 1837 be inserted in the running kernel, rather than being
>> 1838 permanently built into the kernel. You use the "modprobe"
>> 1839 tool to add (and sometimes remove) them. If you say Y here,
>> 1840 many parts of the kernel can be built as modules (by
>> 1841 answering M instead of Y where indicated): this is most
>> 1842 useful for infrequently used options which are not required
>> 1843 for booting. For more information, see the man pages for
>> 1844 modprobe, lsmod, modinfo, insmod and rmmod.
>> 1845
>> 1846 If you say Y here, you will need to run "make
>> 1847 modules_install" to put the modules under /lib/modules/
>> 1848 where modprobe can find them (you may need to be root to do
>> 1849 this).
>> 1850
>> 1851 If unsure, say Y.
>> 1852
>> 1853 if MODULES
>> 1854
>> 1855 config MODULE_FORCE_LOAD
>> 1856 bool "Forced module loading"
>> 1857 default n
>> 1858 help
>> 1859 Allow loading of modules without version information (ie. modprobe
>> 1860 --force). Forced module loading sets the 'F' (forced) taint flag and
>> 1861 is usually a really bad idea.
>> 1862
>> 1863 config MODULE_UNLOAD
>> 1864 bool "Module unloading"
>> 1865 help
>> 1866 Without this option you will not be able to unload any
>> 1867 modules (note that some modules may not be unloadable
>> 1868 anyway), which makes your kernel smaller, faster
>> 1869 and simpler. If unsure, say Y.
>> 1870
>> 1871 config MODULE_FORCE_UNLOAD
>> 1872 bool "Forced module unloading"
>> 1873 depends on MODULE_UNLOAD
>> 1874 help
>> 1875 This option allows you to force a module to unload, even if the
>> 1876 kernel believes it is unsafe: the kernel will remove the module
>> 1877 without waiting for anyone to stop using it (using the -f option to
>> 1878 rmmod). This is mainly for kernel developers and desperate users.
>> 1879 If unsure, say N.
>> 1880
>> 1881 config MODVERSIONS
>> 1882 bool "Module versioning support"
>> 1883 help
>> 1884 Usually, you have to use modules compiled with your kernel.
>> 1885 Saying Y here makes it sometimes possible to use modules
>> 1886 compiled for different kernels, by adding enough information
>> 1887 to the modules to (hopefully) spot any changes which would
>> 1888 make them incompatible with the kernel you are running. If
>> 1889 unsure, say N.
>> 1890
>> 1891 config MODULE_REL_CRCS
>> 1892 bool
>> 1893 depends on MODVERSIONS
>> 1894
>> 1895 config MODULE_SRCVERSION_ALL
>> 1896 bool "Source checksum for all modules"
>> 1897 help
>> 1898 Modules which contain a MODULE_VERSION get an extra "srcversion"
>> 1899 field inserted into their modinfo section, which contains a
>> 1900 sum of the source files which made it. This helps maintainers
>> 1901 see exactly which source was used to build a module (since
>> 1902 others sometimes change the module source without updating
>> 1903 the version). With this option, such a "srcversion" field
>> 1904 will be created for all modules. If unsure, say N.
>> 1905
>> 1906 config MODULE_SIG
>> 1907 bool "Module signature verification"
>> 1908 depends on MODULES
2005 select SYSTEM_DATA_VERIFICATION 1909 select SYSTEM_DATA_VERIFICATION
>> 1910 help
>> 1911 Check modules for valid signatures upon load: the signature
>> 1912 is simply appended to the module. For more information see
>> 1913 <file:Documentation/admin-guide/module-signing.rst>.
>> 1914
>> 1915 Note that this option adds the OpenSSL development packages as a
>> 1916 kernel build dependency so that the signing tool can use its crypto
>> 1917 library.
>> 1918
>> 1919 !!!WARNING!!! If you enable this option, you MUST make sure that the
>> 1920 module DOES NOT get stripped after being signed. This includes the
>> 1921 debuginfo strip done by some packagers (such as rpmbuild) and
>> 1922 inclusion into an initramfs that wants the module size reduced.
>> 1923
>> 1924 config MODULE_SIG_FORCE
>> 1925 bool "Require modules to be validly signed"
>> 1926 depends on MODULE_SIG
>> 1927 help
>> 1928 Reject unsigned modules or signed modules for which we don't have a
>> 1929 key. Without this, such modules will simply taint the kernel.
>> 1930
>> 1931 config MODULE_SIG_ALL
>> 1932 bool "Automatically sign all modules"
>> 1933 default y
>> 1934 depends on MODULE_SIG
>> 1935 help
>> 1936 Sign all modules during make modules_install. Without this option,
>> 1937 modules must be signed manually, using the scripts/sign-file tool.
>> 1938
>> 1939 comment "Do not forget to sign required modules with scripts/sign-file"
>> 1940 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
>> 1941
>> 1942 choice
>> 1943 prompt "Which hash algorithm should modules be signed with?"
>> 1944 depends on MODULE_SIG
>> 1945 help
>> 1946 This determines which sort of hashing algorithm will be used during
>> 1947 signature generation. This algorithm _must_ be built into the kernel
>> 1948 directly so that signature verification can take place. It is not
>> 1949 possible to load a signed module containing the algorithm to check
>> 1950 the signature on that module.
>> 1951
>> 1952 config MODULE_SIG_SHA1
>> 1953 bool "Sign modules with SHA-1"
>> 1954 select CRYPTO_SHA1
>> 1955
>> 1956 config MODULE_SIG_SHA224
>> 1957 bool "Sign modules with SHA-224"
>> 1958 select CRYPTO_SHA256
>> 1959
>> 1960 config MODULE_SIG_SHA256
>> 1961 bool "Sign modules with SHA-256"
>> 1962 select CRYPTO_SHA256
>> 1963
>> 1964 config MODULE_SIG_SHA384
>> 1965 bool "Sign modules with SHA-384"
>> 1966 select CRYPTO_SHA512
>> 1967
>> 1968 config MODULE_SIG_SHA512
>> 1969 bool "Sign modules with SHA-512"
>> 1970 select CRYPTO_SHA512
>> 1971
>> 1972 endchoice
>> 1973
>> 1974 config MODULE_SIG_HASH
>> 1975 string
>> 1976 depends on MODULE_SIG
>> 1977 default "sha1" if MODULE_SIG_SHA1
>> 1978 default "sha224" if MODULE_SIG_SHA224
>> 1979 default "sha256" if MODULE_SIG_SHA256
>> 1980 default "sha384" if MODULE_SIG_SHA384
>> 1981 default "sha512" if MODULE_SIG_SHA512
>> 1982
>> 1983 config MODULE_COMPRESS
>> 1984 bool "Compress modules on installation"
>> 1985 depends on MODULES
>> 1986 help
>> 1987
>> 1988 Compresses kernel modules when 'make modules_install' is run; gzip or
>> 1989 xz depending on "Compression algorithm" below.
>> 1990
>> 1991 module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
>> 1992
>> 1993 Out-of-tree kernel modules installed using Kbuild will also be
>> 1994 compressed upon installation.
2006 1995
2007 source "kernel/module/Kconfig" !! 1996 Note: for modules inside an initrd or initramfs, it's more efficient
>> 1997 to compress the whole initrd or initramfs instead.
>> 1998
>> 1999 Note: This is fully compatible with signed modules.
>> 2000
>> 2001 If in doubt, say N.
>> 2002
>> 2003 choice
>> 2004 prompt "Compression algorithm"
>> 2005 depends on MODULE_COMPRESS
>> 2006 default MODULE_COMPRESS_GZIP
>> 2007 help
>> 2008 This determines which sort of compression will be used during
>> 2009 'make modules_install'.
>> 2010
>> 2011 GZIP (default) and XZ are supported.
>> 2012
>> 2013 config MODULE_COMPRESS_GZIP
>> 2014 bool "GZIP"
>> 2015
>> 2016 config MODULE_COMPRESS_XZ
>> 2017 bool "XZ"
>> 2018
>> 2019 endchoice
>> 2020
>> 2021 config TRIM_UNUSED_KSYMS
>> 2022 bool "Trim unused exported kernel symbols"
>> 2023 depends on MODULES && !UNUSED_SYMBOLS
>> 2024 help
>> 2025 The kernel and some modules make many symbols available for
>> 2026 other modules to use via EXPORT_SYMBOL() and variants. Depending
>> 2027 on the set of modules being selected in your kernel configuration,
>> 2028 many of those exported symbols might never be used.
>> 2029
>> 2030 This option allows for unused exported symbols to be dropped from
>> 2031 the build. In turn, this provides the compiler more opportunities
>> 2032 (especially when using LTO) for optimizing the code and reducing
>> 2033 binary size. This might have some security advantages as well.
>> 2034
>> 2035 If unsure, or if you need to build out-of-tree modules, say N.
>> 2036
>> 2037 endif # MODULES
>> 2038
>> 2039 config MODULES_TREE_LOOKUP
>> 2040 def_bool y
>> 2041 depends on PERF_EVENTS || TRACING
2008 2042
2009 config INIT_ALL_POSSIBLE 2043 config INIT_ALL_POSSIBLE
2010 bool 2044 bool
2011 help 2045 help
2012 Back when each arch used to define 2046 Back when each arch used to define their own cpu_online_mask and
2013 cpu_possible_mask, some of them cho 2047 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
2014 with all 1s, and others with all 0s 2048 with all 1s, and others with all 0s. When they were centralised,
2015 it was better to provide this optio 2049 it was better to provide this option than to break all the archs
2016 and have several arch maintainers p 2050 and have several arch maintainers pursuing me down dark alleys.
2017 2051
2018 source "block/Kconfig" 2052 source "block/Kconfig"
2019 2053
2020 config PREEMPT_NOTIFIERS 2054 config PREEMPT_NOTIFIERS
2021 bool 2055 bool
2022 2056
2023 config PADATA 2057 config PADATA
2024 depends on SMP 2058 depends on SMP
2025 bool 2059 bool
2026 2060
2027 config ASN1 2061 config ASN1
2028 tristate 2062 tristate
2029 help 2063 help
2030 Build a simple ASN.1 grammar compil 2064 Build a simple ASN.1 grammar compiler that produces a bytecode output
2031 that can be interpreted by the ASN. 2065 that can be interpreted by the ASN.1 stream decoder and used to
2032 inform it as to what tags are to be 2066 inform it as to what tags are to be expected in a stream and what
2033 functions to call on what tags. 2067 functions to call on what tags.
2034 2068
2035 source "kernel/Kconfig.locks" 2069 source "kernel/Kconfig.locks"
2036 <<
2037 config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE <<
2038 bool <<
2039 <<
2040 config ARCH_HAS_PREPARE_SYNC_CORE_CMD <<
2041 bool <<
2042 2070
2043 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2071 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
2044 bool 2072 bool
2045 2073
2046 # It may be useful for an architecture to ove 2074 # It may be useful for an architecture to override the definitions of the
2047 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() ma 2075 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h>
2048 # and the COMPAT_ variants in <linux/compat.h 2076 # and the COMPAT_ variants in <linux/compat.h>, in particular to use a
2049 # different calling convention for syscalls. 2077 # different calling convention for syscalls. They can also override the
2050 # macros for not-implemented syscalls in kern 2078 # macros for not-implemented syscalls in kernel/sys_ni.c and
2051 # kernel/time/posix-stubs.c. All these overri 2079 # kernel/time/posix-stubs.c. All these overrides need to be available in
2052 # <asm/syscall_wrapper.h>. 2080 # <asm/syscall_wrapper.h>.
2053 config ARCH_HAS_SYSCALL_WRAPPER 2081 config ARCH_HAS_SYSCALL_WRAPPER
2054 def_bool n 2082 def_bool n
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