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