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