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 <<
30 config CLANG_VERSION <<
31 int <<
32 default $(cc-version) if CC_IS_CLANG <<
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 21
55 config LD_IS_LLD 22 config LD_IS_LLD
56 def_bool $(success,test "$(ld-name)" = !! 23 def_bool $(success,$(LD) -v | head -n 1 | grep -q LLD)
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 24
70 config RUST_IS_AVAILABLE !! 25 config CLANG_VERSION
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 26 int
83 default $(rustc-llvm-version) !! 27 default $(shell,$(srctree)/scripts/clang-version.sh $(CC))
84 28
85 config CC_CAN_LINK !! 29 config CC_HAS_ASM_GOTO
86 bool !! 30 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 31
127 config CONSTRUCTORS 32 config CONSTRUCTORS
128 bool 33 bool
>> 34 depends on !UML
129 35
130 config IRQ_WORK 36 config IRQ_WORK
131 def_bool y if SMP !! 37 bool
132 38
133 config BUILDTIME_TABLE_SORT !! 39 config BUILDTIME_EXTABLE_SORT
134 bool 40 bool
135 41
136 config THREAD_INFO_IN_TASK 42 config THREAD_INFO_IN_TASK
137 bool 43 bool
138 help 44 help
139 Select this to move thread_info off 45 Select this to move thread_info off the stack into task_struct. To
140 make this work, an arch will need to 46 make this work, an arch will need to remove all thread_info fields
141 except flags and fix any runtime bug 47 except flags and fix any runtime bugs.
142 48
143 One subtle change that will be neede 49 One subtle change that will be needed is to use try_get_task_stack()
144 and put_task_stack() in save_thread_ 50 and put_task_stack() in save_thread_stack_tsk() and get_wchan().
145 51
146 menu "General setup" 52 menu "General setup"
147 53
148 config BROKEN 54 config BROKEN
149 bool 55 bool
150 56
151 config BROKEN_ON_SMP 57 config BROKEN_ON_SMP
152 bool 58 bool
153 depends on BROKEN || !SMP 59 depends on BROKEN || !SMP
154 default y 60 default y
155 61
156 config INIT_ENV_ARG_LIMIT 62 config INIT_ENV_ARG_LIMIT
157 int 63 int
158 default 32 if !UML 64 default 32 if !UML
159 default 128 if UML 65 default 128 if UML
160 help 66 help
161 Maximum of each of the number of arg 67 Maximum of each of the number of arguments and environment
162 variables passed to init from the ke 68 variables passed to init from the kernel command line.
163 69
164 config COMPILE_TEST 70 config COMPILE_TEST
165 bool "Compile also drivers which will 71 bool "Compile also drivers which will not load"
166 depends on HAS_IOMEM 72 depends on HAS_IOMEM
167 help 73 help
168 Some drivers can be compiled on a di 74 Some drivers can be compiled on a different platform than they are
169 intended to be run on. Despite they 75 intended to be run on. Despite they cannot be loaded there (or even
170 when they load they cannot be used d 76 when they load they cannot be used due to missing HW support),
171 developers still, opposing to distri 77 developers still, opposing to distributors, might want to build such
172 drivers to compile-test them. 78 drivers to compile-test them.
173 79
174 If you are a developer and want to b 80 If you are a developer and want to build everything available, say Y
175 here. If you are a user/distributor, 81 here. If you are a user/distributor, say N here to exclude useless
176 drivers to be distributed. 82 drivers to be distributed.
177 83
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 84 config LOCALVERSION
206 string "Local version - append to kern 85 string "Local version - append to kernel release"
207 help 86 help
208 Append an extra string to the end of 87 Append an extra string to the end of your kernel version.
209 This will show up when you type unam 88 This will show up when you type uname, for example.
210 The string you set here will be appe 89 The string you set here will be appended after the contents of
211 any files with a filename matching l 90 any files with a filename matching localversion* in your
212 object and source tree, in that orde 91 object and source tree, in that order. Your total string can
213 be a maximum of 64 characters. 92 be a maximum of 64 characters.
214 93
215 config LOCALVERSION_AUTO 94 config LOCALVERSION_AUTO
216 bool "Automatically append version inf 95 bool "Automatically append version information to the version string"
217 default y 96 default y
218 depends on !COMPILE_TEST 97 depends on !COMPILE_TEST
219 help 98 help
220 This will try to automatically deter 99 This will try to automatically determine if the current tree is a
221 release tree by looking for git tags 100 release tree by looking for git tags that belong to the current
222 top of tree revision. 101 top of tree revision.
223 102
224 A string of the format -gxxxxxxxx wi 103 A string of the format -gxxxxxxxx will be added to the localversion
225 if a git-based tree is found. The s 104 if a git-based tree is found. The string generated by this will be
226 appended after any matching localver 105 appended after any matching localversion* files, and after the value
227 set in CONFIG_LOCALVERSION. 106 set in CONFIG_LOCALVERSION.
228 107
229 (The actual string used here is the !! 108 (The actual string used here is the first eight characters produced
230 by running the command: 109 by running the command:
231 110
232 $ git rev-parse --verify HEAD 111 $ git rev-parse --verify HEAD
233 112
234 which is done within the script "scr 113 which is done within the script "scripts/setlocalversion".)
235 114
236 config BUILD_SALT 115 config BUILD_SALT
237 string "Build ID Salt" !! 116 string "Build ID Salt"
238 default "" !! 117 default ""
239 help !! 118 help
240 The build ID is used to link binarie !! 119 The build ID is used to link binaries and their debug info. Setting
241 this option will use the value in th !! 120 this option will use the value in the calculation of the build id.
242 This is mostly useful for distributi !! 121 This is mostly useful for distributions which want to ensure the
243 build is unique between builds. It's !! 122 build is unique between builds. It's safe to leave the default.
244 123
245 config HAVE_KERNEL_GZIP 124 config HAVE_KERNEL_GZIP
246 bool 125 bool
247 126
248 config HAVE_KERNEL_BZIP2 127 config HAVE_KERNEL_BZIP2
249 bool 128 bool
250 129
251 config HAVE_KERNEL_LZMA 130 config HAVE_KERNEL_LZMA
252 bool 131 bool
253 132
254 config HAVE_KERNEL_XZ 133 config HAVE_KERNEL_XZ
255 bool 134 bool
256 135
257 config HAVE_KERNEL_LZO 136 config HAVE_KERNEL_LZO
258 bool 137 bool
259 138
260 config HAVE_KERNEL_LZ4 139 config HAVE_KERNEL_LZ4
261 bool 140 bool
262 141
263 config HAVE_KERNEL_ZSTD <<
264 bool <<
265 <<
266 config HAVE_KERNEL_UNCOMPRESSED 142 config HAVE_KERNEL_UNCOMPRESSED
267 bool 143 bool
268 144
269 choice 145 choice
270 prompt "Kernel compression mode" 146 prompt "Kernel compression mode"
271 default KERNEL_GZIP 147 default KERNEL_GZIP
272 depends on HAVE_KERNEL_GZIP || HAVE_KE !! 148 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 149 help
274 The linux kernel is a kind of self-e 150 The linux kernel is a kind of self-extracting executable.
275 Several compression algorithms are a 151 Several compression algorithms are available, which differ
276 in efficiency, compression and decom 152 in efficiency, compression and decompression speed.
277 Compression speed is only relevant w 153 Compression speed is only relevant when building a kernel.
278 Decompression speed is relevant at e 154 Decompression speed is relevant at each boot.
279 155
280 If you have any problems with bzip2 156 If you have any problems with bzip2 or lzma compressed
281 kernels, mail me (Alain Knaff) <alain 157 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
282 version of this functionality (bzip2 158 version of this functionality (bzip2 only), for 2.4, was
283 supplied by Christian Ludwig) 159 supplied by Christian Ludwig)
284 160
285 High compression options are mostly 161 High compression options are mostly useful for users, who
286 are low on disk space (embedded syst 162 are low on disk space (embedded systems), but for whom ram
287 size matters less. 163 size matters less.
288 164
289 If in doubt, select 'gzip' 165 If in doubt, select 'gzip'
290 166
291 config KERNEL_GZIP 167 config KERNEL_GZIP
292 bool "Gzip" 168 bool "Gzip"
293 depends on HAVE_KERNEL_GZIP 169 depends on HAVE_KERNEL_GZIP
294 help 170 help
295 The old and tried gzip compression. 171 The old and tried gzip compression. It provides a good balance
296 between compression ratio and decomp 172 between compression ratio and decompression speed.
297 173
298 config KERNEL_BZIP2 174 config KERNEL_BZIP2
299 bool "Bzip2" 175 bool "Bzip2"
300 depends on HAVE_KERNEL_BZIP2 176 depends on HAVE_KERNEL_BZIP2
301 help 177 help
302 Its compression ratio and speed is i 178 Its compression ratio and speed is intermediate.
303 Decompression speed is slowest among 179 Decompression speed is slowest among the choices. The kernel
304 size is about 10% smaller with bzip2 180 size is about 10% smaller with bzip2, in comparison to gzip.
305 Bzip2 uses a large amount of memory. 181 Bzip2 uses a large amount of memory. For modern kernels you
306 will need at least 8MB RAM or more f 182 will need at least 8MB RAM or more for booting.
307 183
308 config KERNEL_LZMA 184 config KERNEL_LZMA
309 bool "LZMA" 185 bool "LZMA"
310 depends on HAVE_KERNEL_LZMA 186 depends on HAVE_KERNEL_LZMA
311 help 187 help
312 This compression algorithm's ratio i 188 This compression algorithm's ratio is best. Decompression speed
313 is between gzip and bzip2. Compress 189 is between gzip and bzip2. Compression is slowest.
314 The kernel size is about 33% smaller 190 The kernel size is about 33% smaller with LZMA in comparison to gzip.
315 191
316 config KERNEL_XZ 192 config KERNEL_XZ
317 bool "XZ" 193 bool "XZ"
318 depends on HAVE_KERNEL_XZ 194 depends on HAVE_KERNEL_XZ
319 help 195 help
320 XZ uses the LZMA2 algorithm and inst 196 XZ uses the LZMA2 algorithm and instruction set specific
321 BCJ filters which can improve compre 197 BCJ filters which can improve compression ratio of executable
322 code. The size of the kernel is abou 198 code. The size of the kernel is about 30% smaller with XZ in
323 comparison to gzip. On architectures 199 comparison to gzip. On architectures for which there is a BCJ
324 filter (i386, x86_64, ARM, ARM64, RI !! 200 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
325 and SPARC), XZ will create a few per !! 201 will create a few percent smaller kernel than plain LZMA.
326 plain LZMA. <<
327 202
328 The speed is about the same as with 203 The speed is about the same as with LZMA: The decompression
329 speed of XZ is better than that of b 204 speed of XZ is better than that of bzip2 but worse than gzip
330 and LZO. Compression is slow. 205 and LZO. Compression is slow.
331 206
332 config KERNEL_LZO 207 config KERNEL_LZO
333 bool "LZO" 208 bool "LZO"
334 depends on HAVE_KERNEL_LZO 209 depends on HAVE_KERNEL_LZO
335 help 210 help
336 Its compression ratio is the poorest 211 Its compression ratio is the poorest among the choices. The kernel
337 size is about 10% bigger than gzip; 212 size is about 10% bigger than gzip; however its speed
338 (both compression and decompression) 213 (both compression and decompression) is the fastest.
339 214
340 config KERNEL_LZ4 215 config KERNEL_LZ4
341 bool "LZ4" 216 bool "LZ4"
342 depends on HAVE_KERNEL_LZ4 217 depends on HAVE_KERNEL_LZ4
343 help 218 help
344 LZ4 is an LZ77-type compressor with 219 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
345 A preliminary version of LZ4 de/comp 220 A preliminary version of LZ4 de/compression tool is available at
346 <https://code.google.com/p/lz4/>. 221 <https://code.google.com/p/lz4/>.
347 222
348 Its compression ratio is worse than 223 Its compression ratio is worse than LZO. The size of the kernel
349 is about 8% bigger than LZO. But the 224 is about 8% bigger than LZO. But the decompression speed is
350 faster than LZO. 225 faster than LZO.
351 226
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 227 config KERNEL_UNCOMPRESSED
363 bool "None" 228 bool "None"
364 depends on HAVE_KERNEL_UNCOMPRESSED 229 depends on HAVE_KERNEL_UNCOMPRESSED
365 help 230 help
366 Produce uncompressed kernel image. T 231 Produce uncompressed kernel image. This option is usually not what
367 you want. It is useful for debugging 232 you want. It is useful for debugging the kernel in slow simulation
368 environments, where decompressing an 233 environments, where decompressing and moving the kernel is awfully
369 slow. This option allows early boot 234 slow. This option allows early boot code to skip the decompressor
370 and jump right at uncompressed kerne 235 and jump right at uncompressed kernel image.
371 236
372 endchoice 237 endchoice
373 238
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 239 config DEFAULT_HOSTNAME
385 string "Default hostname" 240 string "Default hostname"
386 default "(none)" 241 default "(none)"
387 help 242 help
388 This option determines the default s 243 This option determines the default system hostname before userspace
389 calls sethostname(2). The kernel tra 244 calls sethostname(2). The kernel traditionally uses "(none)" here,
390 but you may wish to use a different 245 but you may wish to use a different default here to make a minimal
391 system more usable with less configu 246 system more usable with less configuration.
392 247
>> 248 #
>> 249 # For some reason microblaze and nios2 hard code SWAP=n. Hopefully we can
>> 250 # add proper SWAP support to them, in which case this can be remove.
>> 251 #
>> 252 config ARCH_NO_SWAP
>> 253 bool
>> 254
>> 255 config SWAP
>> 256 bool "Support for paging of anonymous memory (swap)"
>> 257 depends on MMU && BLOCK && !ARCH_NO_SWAP
>> 258 default y
>> 259 help
>> 260 This option allows you to choose whether you want to have support
>> 261 for so called swap devices or swap files in your kernel that are
>> 262 used to provide more virtual memory than the actual RAM present
>> 263 in your computer. If unsure say Y.
>> 264
393 config SYSVIPC 265 config SYSVIPC
394 bool "System V IPC" 266 bool "System V IPC"
395 help !! 267 ---help---
396 Inter Process Communication is a sui 268 Inter Process Communication is a suite of library functions and
397 system calls which let processes (ru 269 system calls which let processes (running programs) synchronize and
398 exchange information. It is generall 270 exchange information. It is generally considered to be a good thing,
399 and some programs won't run unless y 271 and some programs won't run unless you say Y here. In particular, if
400 you want to run the DOS emulator dos 272 you want to run the DOS emulator dosemu under Linux (read the
401 DOSEMU-HOWTO, available from <http:/ 273 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
402 you'll need to say Y here. 274 you'll need to say Y here.
403 275
404 You can find documentation about IPC 276 You can find documentation about IPC with "info ipc" and also in
405 section 6.4 of the Linux Programmer' 277 section 6.4 of the Linux Programmer's Guide, available from
406 <http://www.tldp.org/guides.html>. 278 <http://www.tldp.org/guides.html>.
407 279
408 config SYSVIPC_SYSCTL 280 config SYSVIPC_SYSCTL
409 bool 281 bool
410 depends on SYSVIPC 282 depends on SYSVIPC
411 depends on SYSCTL 283 depends on SYSCTL
412 default y 284 default y
413 285
414 config SYSVIPC_COMPAT <<
415 def_bool y <<
416 depends on COMPAT && SYSVIPC <<
417 <<
418 config POSIX_MQUEUE 286 config POSIX_MQUEUE
419 bool "POSIX Message Queues" 287 bool "POSIX Message Queues"
420 depends on NET 288 depends on NET
421 help !! 289 ---help---
422 POSIX variant of message queues is a 290 POSIX variant of message queues is a part of IPC. In POSIX message
423 queues every message has a priority 291 queues every message has a priority which decides about succession
424 of receiving it by a process. If you 292 of receiving it by a process. If you want to compile and run
425 programs written e.g. for Solaris wi 293 programs written e.g. for Solaris with use of its POSIX message
426 queues (functions mq_*) say Y here. 294 queues (functions mq_*) say Y here.
427 295
428 POSIX message queues are visible as 296 POSIX message queues are visible as a filesystem called 'mqueue'
429 and can be mounted somewhere if you 297 and can be mounted somewhere if you want to do filesystem
430 operations on message queues. 298 operations on message queues.
431 299
432 If unsure, say Y. 300 If unsure, say Y.
433 301
434 config POSIX_MQUEUE_SYSCTL 302 config POSIX_MQUEUE_SYSCTL
435 bool 303 bool
436 depends on POSIX_MQUEUE 304 depends on POSIX_MQUEUE
437 depends on SYSCTL 305 depends on SYSCTL
438 default y 306 default y
439 307
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 308 config CROSS_MEMORY_ATTACH
453 bool "Enable process_vm_readv/writev s 309 bool "Enable process_vm_readv/writev syscalls"
454 depends on MMU 310 depends on MMU
455 default y 311 default y
456 help 312 help
457 Enabling this option adds the system 313 Enabling this option adds the system calls process_vm_readv and
458 process_vm_writev which allow a proc 314 process_vm_writev which allow a process with the correct privileges
459 to directly read from or write to an 315 to directly read from or write to another process' address space.
460 See the man page for more details. 316 See the man page for more details.
461 317
462 config USELIB 318 config USELIB
463 bool "uselib syscall (for libc5 and ea !! 319 bool "uselib syscall"
464 default ALPHA || M68K || SPARC !! 320 def_bool ALPHA || M68K || SPARC || X86_32 || IA32_EMULATION
465 help 321 help
466 This option enables the uselib sysca 322 This option enables the uselib syscall, a system call used in the
467 dynamic linker from libc5 and earlie 323 dynamic linker from libc5 and earlier. glibc does not use this
468 system call. If you intend to run p 324 system call. If you intend to run programs built on libc5 or
469 earlier, you may need to enable this 325 earlier, you may need to enable this syscall. Current systems
470 running glibc can safely disable thi 326 running glibc can safely disable this.
471 327
472 config AUDIT 328 config AUDIT
473 bool "Auditing support" 329 bool "Auditing support"
474 depends on NET 330 depends on NET
475 help 331 help
476 Enable auditing infrastructure that 332 Enable auditing infrastructure that can be used with another
477 kernel subsystem, such as SELinux (w 333 kernel subsystem, such as SELinux (which requires this for
478 logging of avc messages output). Sy 334 logging of avc messages output). System call auditing is included
479 on architectures which support it. 335 on architectures which support it.
480 336
481 config HAVE_ARCH_AUDITSYSCALL 337 config HAVE_ARCH_AUDITSYSCALL
482 bool 338 bool
483 339
484 config AUDITSYSCALL 340 config AUDITSYSCALL
485 def_bool y 341 def_bool y
486 depends on AUDIT && HAVE_ARCH_AUDITSYS 342 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
>> 343
>> 344 config AUDIT_WATCH
>> 345 def_bool y
>> 346 depends on AUDITSYSCALL
>> 347 select FSNOTIFY
>> 348
>> 349 config AUDIT_TREE
>> 350 def_bool y
>> 351 depends on AUDITSYSCALL
487 select FSNOTIFY 352 select FSNOTIFY
488 353
489 source "kernel/irq/Kconfig" 354 source "kernel/irq/Kconfig"
490 source "kernel/time/Kconfig" 355 source "kernel/time/Kconfig"
491 source "kernel/bpf/Kconfig" <<
492 source "kernel/Kconfig.preempt" 356 source "kernel/Kconfig.preempt"
493 357
494 menu "CPU/Task time and stats accounting" 358 menu "CPU/Task time and stats accounting"
495 359
496 config VIRT_CPU_ACCOUNTING 360 config VIRT_CPU_ACCOUNTING
497 bool 361 bool
498 362
499 choice 363 choice
500 prompt "Cputime accounting" 364 prompt "Cputime accounting"
501 default TICK_CPU_ACCOUNTING !! 365 default TICK_CPU_ACCOUNTING if !PPC64
>> 366 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
502 367
503 # Kind of a stub config for the pure tick base 368 # Kind of a stub config for the pure tick based cputime accounting
504 config TICK_CPU_ACCOUNTING 369 config TICK_CPU_ACCOUNTING
505 bool "Simple tick based cputime accoun 370 bool "Simple tick based cputime accounting"
506 depends on !S390 && !NO_HZ_FULL 371 depends on !S390 && !NO_HZ_FULL
507 help 372 help
508 This is the basic tick based cputime 373 This is the basic tick based cputime accounting that maintains
509 statistics about user, system and id 374 statistics about user, system and idle time spent on per jiffies
510 granularity. 375 granularity.
511 376
512 If unsure, say Y. 377 If unsure, say Y.
513 378
514 config VIRT_CPU_ACCOUNTING_NATIVE 379 config VIRT_CPU_ACCOUNTING_NATIVE
515 bool "Deterministic task and CPU time 380 bool "Deterministic task and CPU time accounting"
516 depends on HAVE_VIRT_CPU_ACCOUNTING && 381 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
517 select VIRT_CPU_ACCOUNTING 382 select VIRT_CPU_ACCOUNTING
518 help 383 help
519 Select this option to enable more ac 384 Select this option to enable more accurate task and CPU time
520 accounting. This is done by reading 385 accounting. This is done by reading a CPU counter on each
521 kernel entry and exit and on transit 386 kernel entry and exit and on transitions within the kernel
522 between system, softirq and hardirq 387 between system, softirq and hardirq state, so there is a
523 small performance impact. In the ca 388 small performance impact. In the case of s390 or IBM POWER > 5,
524 this also enables accounting of stol 389 this also enables accounting of stolen time on logically-partitioned
525 systems. 390 systems.
526 391
527 config VIRT_CPU_ACCOUNTING_GEN 392 config VIRT_CPU_ACCOUNTING_GEN
528 bool "Full dynticks CPU time accountin 393 bool "Full dynticks CPU time accounting"
529 depends on HAVE_CONTEXT_TRACKING_USER !! 394 depends on HAVE_CONTEXT_TRACKING
530 depends on HAVE_VIRT_CPU_ACCOUNTING_GE 395 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
531 depends on GENERIC_CLOCKEVENTS <<
532 select VIRT_CPU_ACCOUNTING 396 select VIRT_CPU_ACCOUNTING
533 select CONTEXT_TRACKING_USER !! 397 select CONTEXT_TRACKING
534 help 398 help
535 Select this option to enable task an 399 Select this option to enable task and CPU time accounting on full
536 dynticks systems. This accounting is 400 dynticks systems. This accounting is implemented by watching every
537 kernel-user boundaries using the con 401 kernel-user boundaries using the context tracking subsystem.
538 The accounting is thus performed at 402 The accounting is thus performed at the expense of some significant
539 overhead. 403 overhead.
540 404
541 For now this is only useful if you a 405 For now this is only useful if you are working on the full
542 dynticks subsystem development. 406 dynticks subsystem development.
543 407
544 If unsure, say N. 408 If unsure, say N.
545 409
546 endchoice 410 endchoice
547 411
548 config IRQ_TIME_ACCOUNTING 412 config IRQ_TIME_ACCOUNTING
549 bool "Fine granularity task level IRQ 413 bool "Fine granularity task level IRQ time accounting"
550 depends on HAVE_IRQ_TIME_ACCOUNTING && 414 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
551 help 415 help
552 Select this option to enable fine gr 416 Select this option to enable fine granularity task irq time
553 accounting. This is done by reading 417 accounting. This is done by reading a timestamp on each
554 transitions between softirq and hard 418 transitions between softirq and hardirq state, so there can be a
555 small performance impact. 419 small performance impact.
556 420
557 If in doubt, say N here. 421 If in doubt, say N here.
558 422
559 config HAVE_SCHED_AVG_IRQ 423 config HAVE_SCHED_AVG_IRQ
560 def_bool y 424 def_bool y
561 depends on IRQ_TIME_ACCOUNTING || PARA 425 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING
562 depends on SMP 426 depends on SMP
563 427
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 428 config BSD_PROCESS_ACCT
584 bool "BSD Process Accounting" 429 bool "BSD Process Accounting"
585 depends on MULTIUSER 430 depends on MULTIUSER
586 help 431 help
587 If you say Y here, a user level prog 432 If you say Y here, a user level program will be able to instruct the
588 kernel (via a special system call) t 433 kernel (via a special system call) to write process accounting
589 information to a file: whenever a pr 434 information to a file: whenever a process exits, information about
590 that process will be appended to the 435 that process will be appended to the file by the kernel. The
591 information includes things such as 436 information includes things such as creation time, owning user,
592 command name, memory usage, controll 437 command name, memory usage, controlling terminal etc. (the complete
593 list is in the struct acct in <file: 438 list is in the struct acct in <file:include/linux/acct.h>). It is
594 up to the user level program to do u 439 up to the user level program to do useful things with this
595 information. This is generally a go 440 information. This is generally a good idea, so say Y.
596 441
597 config BSD_PROCESS_ACCT_V3 442 config BSD_PROCESS_ACCT_V3
598 bool "BSD Process Accounting version 3 443 bool "BSD Process Accounting version 3 file format"
599 depends on BSD_PROCESS_ACCT 444 depends on BSD_PROCESS_ACCT
600 default n 445 default n
601 help 446 help
602 If you say Y here, the process accou 447 If you say Y here, the process accounting information is written
603 in a new file format that also logs 448 in a new file format that also logs the process IDs of each
604 process and its parent. Note that th 449 process and its parent. Note that this file format is incompatible
605 with previous v0/v1/v2 file formats, 450 with previous v0/v1/v2 file formats, so you will need updated tools
606 for processing it. A preliminary ver 451 for processing it. A preliminary version of these tools is available
607 at <http://www.gnu.org/software/acct 452 at <http://www.gnu.org/software/acct/>.
608 453
609 config TASKSTATS 454 config TASKSTATS
610 bool "Export task/process statistics t 455 bool "Export task/process statistics through netlink"
611 depends on NET 456 depends on NET
612 depends on MULTIUSER 457 depends on MULTIUSER
613 default n 458 default n
614 help 459 help
615 Export selected statistics for tasks 460 Export selected statistics for tasks/processes through the
616 generic netlink interface. Unlike BS 461 generic netlink interface. Unlike BSD process accounting, the
617 statistics are available during the 462 statistics are available during the lifetime of tasks/processes as
618 responses to commands. Like BSD acco 463 responses to commands. Like BSD accounting, they are sent to user
619 space on task exit. 464 space on task exit.
620 465
621 Say N if unsure. 466 Say N if unsure.
622 467
623 config TASK_DELAY_ACCT 468 config TASK_DELAY_ACCT
624 bool "Enable per-task delay accounting 469 bool "Enable per-task delay accounting"
625 depends on TASKSTATS 470 depends on TASKSTATS
626 select SCHED_INFO 471 select SCHED_INFO
627 help 472 help
628 Collect information on time spent by 473 Collect information on time spent by a task waiting for system
629 resources like cpu, synchronous bloc 474 resources like cpu, synchronous block I/O completion and swapping
630 in pages. Such statistics can help i 475 in pages. Such statistics can help in setting a task's priorities
631 relative to other tasks for cpu, io, 476 relative to other tasks for cpu, io, rss limits etc.
632 477
633 Say N if unsure. 478 Say N if unsure.
634 479
635 config TASK_XACCT 480 config TASK_XACCT
636 bool "Enable extended accounting over 481 bool "Enable extended accounting over taskstats"
637 depends on TASKSTATS 482 depends on TASKSTATS
638 help 483 help
639 Collect extended task accounting dat 484 Collect extended task accounting data and send the data
640 to userland for processing over the 485 to userland for processing over the taskstats interface.
641 486
642 Say N if unsure. 487 Say N if unsure.
643 488
644 config TASK_IO_ACCOUNTING 489 config TASK_IO_ACCOUNTING
645 bool "Enable per-task storage I/O acco 490 bool "Enable per-task storage I/O accounting"
646 depends on TASK_XACCT 491 depends on TASK_XACCT
647 help 492 help
648 Collect information on the number of 493 Collect information on the number of bytes of storage I/O which this
649 task has caused. 494 task has caused.
650 495
651 Say N if unsure. 496 Say N if unsure.
652 497
653 config PSI <<
654 bool "Pressure stall information track <<
655 select KERNFS <<
656 help <<
657 Collect metrics that indicate how ov <<
658 and IO capacity are in the system. <<
659 <<
660 If you say Y here, the kernel will c <<
661 pressure statistics files cpu, memor <<
662 the share of walltime in which some <<
663 delayed due to contention of the res <<
664 <<
665 In kernels with cgroup support, cgro <<
666 have cpu.pressure, memory.pressure, <<
667 which aggregate pressure stalls for <<
668 <<
669 For more details see Documentation/a <<
670 <<
671 Say N if unsure. <<
672 <<
673 config PSI_DEFAULT_DISABLED <<
674 bool "Require boot parameter to enable <<
675 default n <<
676 depends on PSI <<
677 help <<
678 If set, pressure stall information t <<
679 per default but can be enabled throu <<
680 kernel commandline during boot. <<
681 <<
682 This feature adds some code to the t <<
683 paths of the scheduler. The overhead <<
684 common scheduling-intense workloads <<
685 webservers, memcache), but it does s <<
686 scheduler stress tests, such as hack <<
687 <<
688 If you are paranoid and not sure wha <<
689 used for, say Y. <<
690 <<
691 Say N if unsure. <<
692 <<
693 endmenu # "CPU/Task time and stats accounting" 498 endmenu # "CPU/Task time and stats accounting"
694 499
695 config CPU_ISOLATION 500 config CPU_ISOLATION
696 bool "CPU isolation" 501 bool "CPU isolation"
697 depends on SMP || COMPILE_TEST 502 depends on SMP || COMPILE_TEST
698 default y 503 default y
699 help 504 help
700 Make sure that CPUs running critical 505 Make sure that CPUs running critical tasks are not disturbed by
701 any source of "noise" such as unboun 506 any source of "noise" such as unbound workqueues, timers, kthreads...
702 Unbound jobs get offloaded to housek 507 Unbound jobs get offloaded to housekeeping CPUs. This is driven by
703 the "isolcpus=" boot parameter. 508 the "isolcpus=" boot parameter.
704 509
705 Say Y if unsure. 510 Say Y if unsure.
706 511
707 source "kernel/rcu/Kconfig" 512 source "kernel/rcu/Kconfig"
708 513
>> 514 config BUILD_BIN2C
>> 515 bool
>> 516 default n
>> 517
709 config IKCONFIG 518 config IKCONFIG
710 tristate "Kernel .config support" 519 tristate "Kernel .config support"
711 help !! 520 select BUILD_BIN2C
>> 521 ---help---
712 This option enables the complete Lin 522 This option enables the complete Linux kernel ".config" file
713 contents to be saved in the kernel. 523 contents to be saved in the kernel. It provides documentation
714 of which kernel options are used in 524 of which kernel options are used in a running kernel or in an
715 on-disk kernel. This information ca 525 on-disk kernel. This information can be extracted from the kernel
716 image file with the script scripts/e 526 image file with the script scripts/extract-ikconfig and used as
717 input to rebuild the current kernel 527 input to rebuild the current kernel or to build another kernel.
718 It can also be extracted from a runn 528 It can also be extracted from a running kernel by reading
719 /proc/config.gz if enabled (below). 529 /proc/config.gz if enabled (below).
720 530
721 config IKCONFIG_PROC 531 config IKCONFIG_PROC
722 bool "Enable access to .config through 532 bool "Enable access to .config through /proc/config.gz"
723 depends on IKCONFIG && PROC_FS 533 depends on IKCONFIG && PROC_FS
724 help !! 534 ---help---
725 This option enables access to the ke 535 This option enables access to the kernel configuration file
726 through /proc/config.gz. 536 through /proc/config.gz.
727 537
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 538 config LOG_BUF_SHIFT
738 int "Kernel log buffer size (16 => 64K 539 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
739 range 12 25 !! 540 range 12 25 if !H8300
>> 541 range 12 19 if H8300
740 default 17 542 default 17
741 depends on PRINTK 543 depends on PRINTK
742 help 544 help
743 Select the minimal kernel log buffer 545 Select the minimal kernel log buffer size as a power of 2.
744 The final size is affected by LOG_CP 546 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
745 parameter, see below. Any higher siz 547 parameter, see below. Any higher size also might be forced
746 by "log_buf_len" boot parameter. 548 by "log_buf_len" boot parameter.
747 549
748 Examples: 550 Examples:
749 17 => 128 KB 551 17 => 128 KB
750 16 => 64 KB 552 16 => 64 KB
751 15 => 32 KB 553 15 => 32 KB
752 14 => 16 KB 554 14 => 16 KB
753 13 => 8 KB 555 13 => 8 KB
754 12 => 4 KB 556 12 => 4 KB
755 557
756 config LOG_CPU_MAX_BUF_SHIFT 558 config LOG_CPU_MAX_BUF_SHIFT
757 int "CPU kernel log buffer size contri 559 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
758 depends on SMP 560 depends on SMP
759 range 0 21 561 range 0 21
>> 562 default 12 if !BASE_SMALL
760 default 0 if BASE_SMALL 563 default 0 if BASE_SMALL
761 default 12 <<
762 depends on PRINTK 564 depends on PRINTK
763 help 565 help
764 This option allows to increase the d 566 This option allows to increase the default ring buffer size
765 according to the number of CPUs. The 567 according to the number of CPUs. The value defines the contribution
766 of each CPU as a power of 2. The use 568 of each CPU as a power of 2. The used space is typically only few
767 lines however it might be much more 569 lines however it might be much more when problems are reported,
768 e.g. backtraces. 570 e.g. backtraces.
769 571
770 The increased size means that a new 572 The increased size means that a new buffer has to be allocated and
771 the original static one is unused. I 573 the original static one is unused. It makes sense only on systems
772 with more CPUs. Therefore this value 574 with more CPUs. Therefore this value is used only when the sum of
773 contributions is greater than the ha 575 contributions is greater than the half of the default kernel ring
774 buffer as defined by LOG_BUF_SHIFT. 576 buffer as defined by LOG_BUF_SHIFT. The default values are set
775 so that more than 16 CPUs are needed !! 577 so that more than 64 CPUs are needed to trigger the allocation.
776 578
777 Also this option is ignored when "lo 579 Also this option is ignored when "log_buf_len" kernel parameter is
778 used as it forces an exact (power of 580 used as it forces an exact (power of two) size of the ring buffer.
779 581
780 The number of possible CPUs is used 582 The number of possible CPUs is used for this computation ignoring
781 hotplugging making the computation o 583 hotplugging making the computation optimal for the worst case
782 scenario while allowing a simple alg 584 scenario while allowing a simple algorithm to be used from bootup.
783 585
784 Examples shift values and their mean 586 Examples shift values and their meaning:
785 17 => 128 KB for each CPU 587 17 => 128 KB for each CPU
786 16 => 64 KB for each CPU 588 16 => 64 KB for each CPU
787 15 => 32 KB for each CPU 589 15 => 32 KB for each CPU
788 14 => 16 KB for each CPU 590 14 => 16 KB for each CPU
789 13 => 8 KB for each CPU 591 13 => 8 KB for each CPU
790 12 => 4 KB for each CPU 592 12 => 4 KB for each CPU
791 593
792 config PRINTK_INDEX !! 594 config PRINTK_SAFE_LOG_BUF_SHIFT
793 bool "Printk indexing debugfs interfac !! 595 int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)"
794 depends on PRINTK && DEBUG_FS !! 596 range 10 21
795 help !! 597 default 13
796 Add support for indexing of all prin !! 598 depends on PRINTK
797 at <debugfs>/printk/index/<module>. !! 599 help
798 !! 600 Select the size of an alternate printk per-CPU buffer where messages
799 This can be used as part of maintain !! 601 printed from usafe contexts are temporary stored. One example would
800 /dev/kmsg, as it permits auditing th !! 602 be NMI messages, another one - printk recursion. The messages are
801 kernel, allowing detection of cases !! 603 copied to the main log buffer in a safe context to avoid a deadlock.
802 changed or no longer present. !! 604 The value defines the size as a power of 2.
>> 605
>> 606 Those messages are rare and limited. The largest one is when
>> 607 a backtrace is printed. It usually fits into 4KB. Select
>> 608 8KB if you want to be on the safe side.
803 609
804 There is no additional runtime cost !! 610 Examples:
>> 611 17 => 128 KB for each CPU
>> 612 16 => 64 KB for each CPU
>> 613 15 => 32 KB for each CPU
>> 614 14 => 16 KB for each CPU
>> 615 13 => 8 KB for each CPU
>> 616 12 => 4 KB for each CPU
805 617
806 # 618 #
807 # Architectures with an unreliable sched_clock 619 # Architectures with an unreliable sched_clock() should select this:
808 # 620 #
809 config HAVE_UNSTABLE_SCHED_CLOCK 621 config HAVE_UNSTABLE_SCHED_CLOCK
810 bool 622 bool
811 623
812 config GENERIC_SCHED_CLOCK 624 config GENERIC_SCHED_CLOCK
813 bool 625 bool
814 626
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 # 627 #
869 # For architectures that want to enable the su 628 # For architectures that want to enable the support for NUMA-affine scheduler
870 # balancing logic: 629 # balancing logic:
871 # 630 #
872 config ARCH_SUPPORTS_NUMA_BALANCING 631 config ARCH_SUPPORTS_NUMA_BALANCING
873 bool 632 bool
874 633
875 # 634 #
876 # For architectures that prefer to flush all T 635 # For architectures that prefer to flush all TLBs after a number of pages
877 # are unmapped instead of sending one IPI per 636 # are unmapped instead of sending one IPI per page to flush. The architecture
878 # must provide guarantees on what happens if a 637 # must provide guarantees on what happens if a clean TLB cache entry is
879 # written after the unmap. Details are in mm/r 638 # written after the unmap. Details are in mm/rmap.c near the check for
880 # should_defer_flush. The architecture should 639 # should_defer_flush. The architecture should also consider if the full flush
881 # and the refill costs are offset by the savin 640 # and the refill costs are offset by the savings of sending fewer IPIs.
882 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 641 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
883 bool 642 bool
884 643
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 # 644 #
915 # For architectures that know their GCC __int1 645 # For architectures that know their GCC __int128 support is sound
916 # 646 #
917 config ARCH_SUPPORTS_INT128 647 config ARCH_SUPPORTS_INT128
918 bool 648 bool
919 649
920 # For architectures that (ab)use NUMA to repre 650 # For architectures that (ab)use NUMA to represent different memory regions
921 # all cpu-local but of different latencies, su 651 # all cpu-local but of different latencies, such as SuperH.
922 # 652 #
923 config ARCH_WANT_NUMA_VARIABLE_LOCALITY 653 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
924 bool 654 bool
925 655
926 config NUMA_BALANCING 656 config NUMA_BALANCING
927 bool "Memory placement aware NUMA sche 657 bool "Memory placement aware NUMA scheduler"
928 depends on ARCH_SUPPORTS_NUMA_BALANCIN 658 depends on ARCH_SUPPORTS_NUMA_BALANCING
929 depends on !ARCH_WANT_NUMA_VARIABLE_LO 659 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
930 depends on SMP && NUMA && MIGRATION && !! 660 depends on SMP && NUMA && MIGRATION
931 help 661 help
932 This option adds support for automat 662 This option adds support for automatic NUMA aware memory/task placement.
933 The mechanism is quite primitive and 663 The mechanism is quite primitive and is based on migrating memory when
934 it has references to the node the ta 664 it has references to the node the task is running on.
935 665
936 This system will be inactive on UMA 666 This system will be inactive on UMA systems.
937 667
938 config NUMA_BALANCING_DEFAULT_ENABLED 668 config NUMA_BALANCING_DEFAULT_ENABLED
939 bool "Automatically enable NUMA aware 669 bool "Automatically enable NUMA aware memory/task placement"
940 default y 670 default y
941 depends on NUMA_BALANCING 671 depends on NUMA_BALANCING
942 help 672 help
943 If set, automatic NUMA balancing wil 673 If set, automatic NUMA balancing will be enabled if running on a NUMA
944 machine. 674 machine.
945 675
946 config SLAB_OBJ_EXT <<
947 bool <<
948 <<
949 menuconfig CGROUPS 676 menuconfig CGROUPS
950 bool "Control Group support" 677 bool "Control Group support"
951 select KERNFS 678 select KERNFS
952 help 679 help
953 This option adds support for groupin 680 This option adds support for grouping sets of processes together, for
954 use with process control subsystems 681 use with process control subsystems such as Cpusets, CFS, memory
955 controls or device isolation. 682 controls or device isolation.
956 See 683 See
957 - Documentation/scheduler/sche !! 684 - Documentation/scheduler/sched-design-CFS.txt (CFS)
958 - Documentation/admin-guide/cg !! 685 - Documentation/cgroup-v1/ (features for grouping, isolation
959 and 686 and resource control)
960 687
961 Say N if unsure. 688 Say N if unsure.
962 689
963 if CGROUPS 690 if CGROUPS
964 691
965 config PAGE_COUNTER 692 config PAGE_COUNTER
966 bool !! 693 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. <<
977 694
978 config MEMCG 695 config MEMCG
979 bool "Memory controller" 696 bool "Memory controller"
980 select PAGE_COUNTER 697 select PAGE_COUNTER
981 select EVENTFD 698 select EVENTFD
982 select SLAB_OBJ_EXT <<
983 help 699 help
984 Provides control over the memory foo 700 Provides control over the memory footprint of tasks in a cgroup.
985 701
986 config MEMCG_V1 !! 702 config MEMCG_SWAP
987 bool "Legacy cgroup v1 memory controll !! 703 bool "Swap controller"
988 depends on MEMCG !! 704 depends on MEMCG && SWAP
989 default n <<
990 help 705 help
991 Legacy cgroup v1 memory controller w !! 706 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 707
1001 Say N if unsure. !! 708 config MEMCG_SWAP_ENABLED
>> 709 bool "Swap controller enabled by default"
>> 710 depends on MEMCG_SWAP
>> 711 default y
>> 712 help
>> 713 Memory Resource Controller Swap Extension comes with its price in
>> 714 a bigger memory consumption. General purpose distribution kernels
>> 715 which want to enable the feature but keep it disabled by default
>> 716 and let the user enable it by swapaccount=1 boot command line
>> 717 parameter should have this option unselected.
>> 718 For those who want to have the feature enabled by default should
>> 719 select this option (if, for some reason, they need to disable it
>> 720 then swapaccount=0 does the trick).
>> 721
>> 722 config MEMCG_KMEM
>> 723 bool
>> 724 depends on MEMCG && !SLOB
>> 725 default y
1002 726
1003 config BLK_CGROUP 727 config BLK_CGROUP
1004 bool "IO controller" 728 bool "IO controller"
1005 depends on BLOCK 729 depends on BLOCK
1006 default n 730 default n
1007 help !! 731 ---help---
1008 Generic block IO controller cgroup in 732 Generic block IO controller cgroup interface. This is the common
1009 cgroup interface which should be used 733 cgroup interface which should be used by various IO controlling
1010 policies. 734 policies.
1011 735
1012 Currently, CFQ IO scheduler uses it t 736 Currently, CFQ IO scheduler uses it to recognize task groups and
1013 control disk bandwidth allocation (pr 737 control disk bandwidth allocation (proportional time slice allocation)
1014 to such task groups. It is also used 738 to such task groups. It is also used by bio throttling logic in
1015 block layer to implement upper limit 739 block layer to implement upper limit in IO rates on a device.
1016 740
1017 This option only enables generic Bloc 741 This option only enables generic Block IO controller infrastructure.
1018 One needs to also enable actual IO co 742 One needs to also enable actual IO controlling logic/policy. For
1019 enabling proportional weight division 743 enabling proportional weight division of disk bandwidth in CFQ, set
1020 CONFIG_BFQ_GROUP_IOSCHED=y; for enabl !! 744 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1021 CONFIG_BLK_DEV_THROTTLING=y. 745 CONFIG_BLK_DEV_THROTTLING=y.
1022 746
1023 See Documentation/admin-guide/cgroup- !! 747 See Documentation/cgroup-v1/blkio-controller.txt for more information.
>> 748
>> 749 config DEBUG_BLK_CGROUP
>> 750 bool "IO controller debugging"
>> 751 depends on BLK_CGROUP
>> 752 default n
>> 753 ---help---
>> 754 Enable some debugging help. Currently it exports additional stat
>> 755 files in a cgroup which can be useful for debugging.
1024 756
1025 config CGROUP_WRITEBACK 757 config CGROUP_WRITEBACK
1026 bool 758 bool
1027 depends on MEMCG && BLK_CGROUP 759 depends on MEMCG && BLK_CGROUP
1028 default y 760 default y
1029 761
1030 menuconfig CGROUP_SCHED 762 menuconfig CGROUP_SCHED
1031 bool "CPU controller" 763 bool "CPU controller"
1032 default n 764 default n
1033 help 765 help
1034 This feature lets CPU scheduler rec 766 This feature lets CPU scheduler recognize task groups and control CPU
1035 bandwidth allocation to such task g 767 bandwidth allocation to such task groups. It uses cgroups to group
1036 tasks. 768 tasks.
1037 769
1038 if CGROUP_SCHED 770 if CGROUP_SCHED
1039 config GROUP_SCHED_WEIGHT <<
1040 def_bool n <<
1041 <<
1042 config FAIR_GROUP_SCHED 771 config FAIR_GROUP_SCHED
1043 bool "Group scheduling for SCHED_OTHE 772 bool "Group scheduling for SCHED_OTHER"
1044 depends on CGROUP_SCHED 773 depends on CGROUP_SCHED
1045 select GROUP_SCHED_WEIGHT <<
1046 default CGROUP_SCHED 774 default CGROUP_SCHED
1047 775
1048 config CFS_BANDWIDTH 776 config CFS_BANDWIDTH
1049 bool "CPU bandwidth provisioning for 777 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1050 depends on FAIR_GROUP_SCHED 778 depends on FAIR_GROUP_SCHED
1051 default n 779 default n
1052 help 780 help
1053 This option allows users to define 781 This option allows users to define CPU bandwidth rates (limits) for
1054 tasks running within the fair group 782 tasks running within the fair group scheduler. Groups with no limit
1055 set are considered to be unconstrai 783 set are considered to be unconstrained and will run with no
1056 restriction. 784 restriction.
1057 See Documentation/scheduler/sched-b !! 785 See Documentation/scheduler/sched-bwc.txt for more information.
1058 786
1059 config RT_GROUP_SCHED 787 config RT_GROUP_SCHED
1060 bool "Group scheduling for SCHED_RR/F 788 bool "Group scheduling for SCHED_RR/FIFO"
1061 depends on CGROUP_SCHED 789 depends on CGROUP_SCHED
1062 default n 790 default n
1063 help 791 help
1064 This feature lets you explicitly al 792 This feature lets you explicitly allocate real CPU bandwidth
1065 to task groups. If enabled, it will 793 to task groups. If enabled, it will also make it impossible to
1066 schedule realtime tasks for non-roo 794 schedule realtime tasks for non-root users until you allocate
1067 realtime bandwidth for them. 795 realtime bandwidth for them.
1068 See Documentation/scheduler/sched-r !! 796 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 797
1076 endif #CGROUP_SCHED 798 endif #CGROUP_SCHED
1077 799
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 800 config CGROUP_PIDS
1105 bool "PIDs controller" 801 bool "PIDs controller"
1106 help 802 help
1107 Provides enforcement of process num 803 Provides enforcement of process number limits in the scope of a
1108 cgroup. Any attempt to fork more pr 804 cgroup. Any attempt to fork more processes than is allowed in the
1109 cgroup will fail. PIDs are fundamen 805 cgroup will fail. PIDs are fundamentally a global resource because it
1110 is fairly trivial to reach PID exha 806 is fairly trivial to reach PID exhaustion before you reach even a
1111 conservative kmemcg limit. As a res 807 conservative kmemcg limit. As a result, it is possible to grind a
1112 system to halt without being limite 808 system to halt without being limited by other cgroup policies. The
1113 PIDs controller is designed to stop 809 PIDs controller is designed to stop this from happening.
1114 810
1115 It should be noted that organisatio 811 It should be noted that organisational operations (such as attaching
1116 to a cgroup hierarchy) will *not* b !! 812 to a cgroup hierarchy will *not* be blocked by the PIDs controller),
1117 since the PIDs limit only affects a 813 since the PIDs limit only affects a process's ability to fork, not to
1118 attach to a cgroup. 814 attach to a cgroup.
1119 815
1120 config CGROUP_RDMA 816 config CGROUP_RDMA
1121 bool "RDMA controller" 817 bool "RDMA controller"
1122 help 818 help
1123 Provides enforcement of RDMA resour 819 Provides enforcement of RDMA resources defined by IB stack.
1124 It is fairly easy for consumers to 820 It is fairly easy for consumers to exhaust RDMA resources, which
1125 can result into resource unavailabi 821 can result into resource unavailability to other consumers.
1126 RDMA controller is designed to stop 822 RDMA controller is designed to stop this from happening.
1127 Attaching processes with active RDM 823 Attaching processes with active RDMA resources to the cgroup
1128 hierarchy is allowed even if can cr 824 hierarchy is allowed even if can cross the hierarchy's limit.
1129 825
1130 config CGROUP_FREEZER 826 config CGROUP_FREEZER
1131 bool "Freezer controller" 827 bool "Freezer controller"
1132 help 828 help
1133 Provides a way to freeze and unfree 829 Provides a way to freeze and unfreeze all tasks in a
1134 cgroup. 830 cgroup.
1135 831
1136 This option affects the ORIGINAL cg 832 This option affects the ORIGINAL cgroup interface. The cgroup2 memory
1137 controller includes important in-ke 833 controller includes important in-kernel memory consumers per default.
1138 834
1139 If you're using cgroup2, say N. 835 If you're using cgroup2, say N.
1140 836
1141 config CGROUP_HUGETLB 837 config CGROUP_HUGETLB
1142 bool "HugeTLB controller" 838 bool "HugeTLB controller"
1143 depends on HUGETLB_PAGE 839 depends on HUGETLB_PAGE
1144 select PAGE_COUNTER 840 select PAGE_COUNTER
1145 default n 841 default n
1146 help 842 help
1147 Provides a cgroup controller for Hu 843 Provides a cgroup controller for HugeTLB pages.
1148 When you enable this, you can put a 844 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1149 The limit is enforced during page f 845 The limit is enforced during page fault. Since HugeTLB doesn't
1150 support page reclaim, enforcing the 846 support page reclaim, enforcing the limit at page fault time implies
1151 that, the application will get SIGB 847 that, the application will get SIGBUS signal if it tries to access
1152 HugeTLB pages beyond its limit. Thi 848 HugeTLB pages beyond its limit. This requires the application to know
1153 beforehand how much HugeTLB pages i 849 beforehand how much HugeTLB pages it would require for its use. The
1154 control group is tracked in the thi 850 control group is tracked in the third page lru pointer. This means
1155 that we cannot use the controller w 851 that we cannot use the controller with huge page less than 3 pages.
1156 852
1157 config CPUSETS 853 config CPUSETS
1158 bool "Cpuset controller" 854 bool "Cpuset controller"
1159 depends on SMP 855 depends on SMP
1160 help 856 help
1161 This option will let you create and 857 This option will let you create and manage CPUSETs which
1162 allow dynamically partitioning a sy 858 allow dynamically partitioning a system into sets of CPUs and
1163 Memory Nodes and assigning tasks to 859 Memory Nodes and assigning tasks to run only within those sets.
1164 This is primarily useful on large S 860 This is primarily useful on large SMP or NUMA systems.
1165 861
1166 Say N if unsure. 862 Say N if unsure.
1167 863
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 864 config PROC_PID_CPUSET
1182 bool "Include legacy /proc/<pid>/cpus 865 bool "Include legacy /proc/<pid>/cpuset file"
1183 depends on CPUSETS 866 depends on CPUSETS
1184 default y 867 default y
1185 868
1186 config CGROUP_DEVICE 869 config CGROUP_DEVICE
1187 bool "Device controller" 870 bool "Device controller"
1188 help 871 help
1189 Provides a cgroup controller implem 872 Provides a cgroup controller implementing whitelists for
1190 devices which a process in the cgro 873 devices which a process in the cgroup can mknod or open.
1191 874
1192 config CGROUP_CPUACCT 875 config CGROUP_CPUACCT
1193 bool "Simple CPU accounting controlle 876 bool "Simple CPU accounting controller"
1194 help 877 help
1195 Provides a simple controller for mo 878 Provides a simple controller for monitoring the
1196 total CPU consumed by the tasks in 879 total CPU consumed by the tasks in a cgroup.
1197 880
1198 config CGROUP_PERF 881 config CGROUP_PERF
1199 bool "Perf controller" 882 bool "Perf controller"
1200 depends on PERF_EVENTS 883 depends on PERF_EVENTS
1201 help 884 help
1202 This option extends the perf per-cp 885 This option extends the perf per-cpu mode to restrict monitoring
1203 to threads which belong to the cgro 886 to threads which belong to the cgroup specified and run on the
1204 designated cpu. Or this can be use !! 887 designated cpu.
1205 so that it can monitor performance <<
1206 888
1207 Say N if unsure. 889 Say N if unsure.
1208 890
1209 config CGROUP_BPF 891 config CGROUP_BPF
1210 bool "Support for eBPF programs attac 892 bool "Support for eBPF programs attached to cgroups"
1211 depends on BPF_SYSCALL 893 depends on BPF_SYSCALL
1212 select SOCK_CGROUP_DATA 894 select SOCK_CGROUP_DATA
1213 help 895 help
1214 Allow attaching eBPF programs to a 896 Allow attaching eBPF programs to a cgroup using the bpf(2)
1215 syscall command BPF_PROG_ATTACH. 897 syscall command BPF_PROG_ATTACH.
1216 898
1217 In which context these programs are 899 In which context these programs are accessed depends on the type
1218 of attachment. For instance, progra 900 of attachment. For instance, programs that are attached using
1219 BPF_CGROUP_INET_INGRESS will be exe 901 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
1220 inet sockets. 902 inet sockets.
1221 903
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 904 config CGROUP_DEBUG
1237 bool "Debug controller" 905 bool "Debug controller"
1238 default n 906 default n
1239 depends on DEBUG_KERNEL 907 depends on DEBUG_KERNEL
1240 help 908 help
1241 This option enables a simple contro 909 This option enables a simple controller that exports
1242 debugging information about the cgr 910 debugging information about the cgroups framework. This
1243 controller is for control cgroup de 911 controller is for control cgroup debugging only. Its
1244 interfaces are not stable. 912 interfaces are not stable.
1245 913
1246 Say N. 914 Say N.
1247 915
1248 config SOCK_CGROUP_DATA 916 config SOCK_CGROUP_DATA
1249 bool 917 bool
1250 default n 918 default n
1251 919
1252 endif # CGROUPS 920 endif # CGROUPS
1253 921
1254 menuconfig NAMESPACES 922 menuconfig NAMESPACES
1255 bool "Namespaces support" if EXPERT 923 bool "Namespaces support" if EXPERT
1256 depends on MULTIUSER 924 depends on MULTIUSER
1257 default !EXPERT 925 default !EXPERT
1258 help 926 help
1259 Provides the way to make tasks work 927 Provides the way to make tasks work with different objects using
1260 the same id. For example same IPC i 928 the same id. For example same IPC id may refer to different objects
1261 or same user id or pid may refer to 929 or same user id or pid may refer to different tasks when used in
1262 different namespaces. 930 different namespaces.
1263 931
1264 if NAMESPACES 932 if NAMESPACES
1265 933
1266 config UTS_NS 934 config UTS_NS
1267 bool "UTS namespace" 935 bool "UTS namespace"
1268 default y 936 default y
1269 help 937 help
1270 In this namespace tasks see differe 938 In this namespace tasks see different info provided with the
1271 uname() system call 939 uname() system call
1272 940
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 941 config IPC_NS
1282 bool "IPC namespace" 942 bool "IPC namespace"
1283 depends on (SYSVIPC || POSIX_MQUEUE) 943 depends on (SYSVIPC || POSIX_MQUEUE)
1284 default y 944 default y
1285 help 945 help
1286 In this namespace tasks work with I 946 In this namespace tasks work with IPC ids which correspond to
1287 different IPC objects in different 947 different IPC objects in different namespaces.
1288 948
1289 config USER_NS 949 config USER_NS
1290 bool "User namespace" 950 bool "User namespace"
1291 default n 951 default n
1292 help 952 help
1293 This allows containers, i.e. vserve 953 This allows containers, i.e. vservers, to use user namespaces
1294 to provide different user info for 954 to provide different user info for different servers.
1295 955
1296 When user namespaces are enabled in 956 When user namespaces are enabled in the kernel it is
1297 recommended that the MEMCG option a 957 recommended that the MEMCG option also be enabled and that
1298 user-space use the memory control g 958 user-space use the memory control groups to limit the amount
1299 of memory a memory unprivileged use 959 of memory a memory unprivileged users can use.
1300 960
1301 If unsure, say N. 961 If unsure, say N.
1302 962
1303 config PID_NS 963 config PID_NS
1304 bool "PID Namespaces" 964 bool "PID Namespaces"
1305 default y 965 default y
1306 help 966 help
1307 Support process id namespaces. Thi 967 Support process id namespaces. This allows having multiple
1308 processes with the same pid as long 968 processes with the same pid as long as they are in different
1309 pid namespaces. This is a building 969 pid namespaces. This is a building block of containers.
1310 970
1311 config NET_NS 971 config NET_NS
1312 bool "Network namespace" 972 bool "Network namespace"
1313 depends on NET 973 depends on NET
1314 default y 974 default y
1315 help 975 help
1316 Allow user space to create what app 976 Allow user space to create what appear to be multiple instances
1317 of the network stack. 977 of the network stack.
1318 978
1319 endif # NAMESPACES 979 endif # NAMESPACES
1320 980
1321 config CHECKPOINT_RESTORE 981 config CHECKPOINT_RESTORE
1322 bool "Checkpoint/restore support" 982 bool "Checkpoint/restore support"
1323 depends on PROC_FS <<
1324 select PROC_CHILDREN 983 select PROC_CHILDREN
1325 select KCMP <<
1326 default n 984 default n
1327 help 985 help
1328 Enables additional kernel features 986 Enables additional kernel features in a sake of checkpoint/restore.
1329 In particular it adds auxiliary prc 987 In particular it adds auxiliary prctl codes to setup process text,
1330 data and heap segment sizes, and a 988 data and heap segment sizes, and a few additional /proc filesystem
1331 entries. 989 entries.
1332 990
1333 If unsure, say N here. 991 If unsure, say N here.
1334 992
1335 config SCHED_AUTOGROUP 993 config SCHED_AUTOGROUP
1336 bool "Automatic process group schedul 994 bool "Automatic process group scheduling"
1337 select CGROUPS 995 select CGROUPS
1338 select CGROUP_SCHED 996 select CGROUP_SCHED
1339 select FAIR_GROUP_SCHED 997 select FAIR_GROUP_SCHED
1340 help 998 help
1341 This option optimizes the scheduler 999 This option optimizes the scheduler for common desktop workloads by
1342 automatically creating and populati 1000 automatically creating and populating task groups. This separation
1343 of workloads isolates aggressive CP 1001 of workloads isolates aggressive CPU burners (like build jobs) from
1344 desktop applications. Task group a 1002 desktop applications. Task group autogeneration is currently based
1345 upon task session. 1003 upon task session.
1346 1004
>> 1005 config SYSFS_DEPRECATED
>> 1006 bool "Enable deprecated sysfs features to support old userspace tools"
>> 1007 depends on SYSFS
>> 1008 default n
>> 1009 help
>> 1010 This option adds code that switches the layout of the "block" class
>> 1011 devices, to not show up in /sys/class/block/, but only in
>> 1012 /sys/block/.
>> 1013
>> 1014 This switch is only active when the sysfs.deprecated=1 boot option is
>> 1015 passed or the SYSFS_DEPRECATED_V2 option is set.
>> 1016
>> 1017 This option allows new kernels to run on old distributions and tools,
>> 1018 which might get confused by /sys/class/block/. Since 2007/2008 all
>> 1019 major distributions and tools handle this just fine.
>> 1020
>> 1021 Recent distributions and userspace tools after 2009/2010 depend on
>> 1022 the existence of /sys/class/block/, and will not work with this
>> 1023 option enabled.
>> 1024
>> 1025 Only if you are using a new kernel on an old distribution, you might
>> 1026 need to say Y here.
>> 1027
>> 1028 config SYSFS_DEPRECATED_V2
>> 1029 bool "Enable deprecated sysfs features by default"
>> 1030 default n
>> 1031 depends on SYSFS
>> 1032 depends on SYSFS_DEPRECATED
>> 1033 help
>> 1034 Enable deprecated sysfs by default.
>> 1035
>> 1036 See the CONFIG_SYSFS_DEPRECATED option for more details about this
>> 1037 option.
>> 1038
>> 1039 Only if you are using a new kernel on an old distribution, you might
>> 1040 need to say Y here. Even then, odds are you would not need it
>> 1041 enabled, you can always pass the boot option if absolutely necessary.
>> 1042
1347 config RELAY 1043 config RELAY
1348 bool "Kernel->user space relay suppor 1044 bool "Kernel->user space relay support (formerly relayfs)"
1349 select IRQ_WORK 1045 select IRQ_WORK
1350 help 1046 help
1351 This option enables support for rel 1047 This option enables support for relay interface support in
1352 certain file systems (such as debug 1048 certain file systems (such as debugfs).
1353 It is designed to provide an effici 1049 It is designed to provide an efficient mechanism for tools and
1354 facilities to relay large amounts o 1050 facilities to relay large amounts of data from kernel space to
1355 user space. 1051 user space.
1356 1052
1357 If unsure, say N. 1053 If unsure, say N.
1358 1054
1359 config BLK_DEV_INITRD 1055 config BLK_DEV_INITRD
1360 bool "Initial RAM filesystem and RAM 1056 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1361 help 1057 help
1362 The initial RAM filesystem is a ram 1058 The initial RAM filesystem is a ramfs which is loaded by the
1363 boot loader (loadlin or lilo) and t 1059 boot loader (loadlin or lilo) and that is mounted as root
1364 before the normal boot procedure. I 1060 before the normal boot procedure. It is typically used to
1365 load modules needed to mount the "r 1061 load modules needed to mount the "real" root file system,
1366 etc. See <file:Documentation/admin- 1062 etc. See <file:Documentation/admin-guide/initrd.rst> for details.
1367 1063
1368 If RAM disk support (BLK_DEV_RAM) i 1064 If RAM disk support (BLK_DEV_RAM) is also included, this
1369 also enables initial RAM disk (init 1065 also enables initial RAM disk (initrd) support and adds
1370 15 Kbytes (more on some other archi 1066 15 Kbytes (more on some other architectures) to the kernel size.
1371 1067
1372 If unsure say Y. 1068 If unsure say Y.
1373 1069
1374 if BLK_DEV_INITRD 1070 if BLK_DEV_INITRD
1375 1071
1376 source "usr/Kconfig" 1072 source "usr/Kconfig"
1377 1073
1378 endif 1074 endif
1379 1075
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 1076 choice
1435 prompt "Compiler optimization level" 1077 prompt "Compiler optimization level"
1436 default CC_OPTIMIZE_FOR_PERFORMANCE 1078 default CC_OPTIMIZE_FOR_PERFORMANCE
1437 1079
1438 config CC_OPTIMIZE_FOR_PERFORMANCE 1080 config CC_OPTIMIZE_FOR_PERFORMANCE
1439 bool "Optimize for performance (-O2)" !! 1081 bool "Optimize for performance"
1440 help 1082 help
1441 This is the default optimization le 1083 This is the default optimization level for the kernel, building
1442 with the "-O2" compiler flag for be 1084 with the "-O2" compiler flag for best performance and most
1443 helpful compile-time warnings. 1085 helpful compile-time warnings.
1444 1086
1445 config CC_OPTIMIZE_FOR_SIZE 1087 config CC_OPTIMIZE_FOR_SIZE
1446 bool "Optimize for size (-Os)" !! 1088 bool "Optimize for size"
1447 help 1089 help
1448 Choosing this option will pass "-Os !! 1090 Enabling this option will pass "-Os" instead of "-O2" to
1449 in a smaller kernel. !! 1091 your compiler resulting in a smaller kernel.
>> 1092
>> 1093 If unsure, say N.
1450 1094
1451 endchoice 1095 endchoice
1452 1096
1453 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1097 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1454 bool 1098 bool
1455 help 1099 help
1456 This requires that the arch annotat 1100 This requires that the arch annotates or otherwise protects
1457 its external entry points from bein 1101 its external entry points from being discarded. Linker scripts
1458 must also merge .text.*, .data.*, a 1102 must also merge .text.*, .data.*, and .bss.* correctly into
1459 output sections. Care must be taken 1103 output sections. Care must be taken not to pull in unrelated
1460 sections (e.g., '.text.init'). Typi 1104 sections (e.g., '.text.init'). Typically '.' in section names
1461 is used to distinguish them from la 1105 is used to distinguish them from label names / C identifiers.
1462 1106
1463 config LD_DEAD_CODE_DATA_ELIMINATION 1107 config LD_DEAD_CODE_DATA_ELIMINATION
1464 bool "Dead code and data elimination 1108 bool "Dead code and data elimination (EXPERIMENTAL)"
1465 depends on HAVE_LD_DEAD_CODE_DATA_ELI 1109 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1466 depends on EXPERT 1110 depends on EXPERT
>> 1111 depends on !(FUNCTION_TRACER && CC_IS_GCC && GCC_VERSION < 40800)
1467 depends on $(cc-option,-ffunction-sec 1112 depends on $(cc-option,-ffunction-sections -fdata-sections)
1468 depends on $(ld-option,--gc-sections) 1113 depends on $(ld-option,--gc-sections)
1469 help 1114 help
1470 Enable this if you want to do dead 1115 Enable this if you want to do dead code and data elimination with
1471 the linker by compiling with -ffunc 1116 the linker by compiling with -ffunction-sections -fdata-sections,
1472 and linking with --gc-sections. 1117 and linking with --gc-sections.
1473 1118
1474 This can reduce on disk and in-memo 1119 This can reduce on disk and in-memory size of the kernel
1475 code and static data, particularly 1120 code and static data, particularly for small configs and
1476 on small systems. This has the poss 1121 on small systems. This has the possibility of introducing
1477 silently broken kernel if the requi 1122 silently broken kernel if the required annotations are not
1478 present. This option is not well te 1123 present. This option is not well tested yet, so use at your
1479 own risk. 1124 own risk.
1480 1125
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 1126 config SYSCTL
1494 bool 1127 bool
1495 1128
>> 1129 config ANON_INODES
>> 1130 bool
>> 1131
1496 config HAVE_UID16 1132 config HAVE_UID16
1497 bool 1133 bool
1498 1134
1499 config SYSCTL_EXCEPTION_TRACE 1135 config SYSCTL_EXCEPTION_TRACE
1500 bool 1136 bool
1501 help 1137 help
1502 Enable support for /proc/sys/debug/ 1138 Enable support for /proc/sys/debug/exception-trace.
1503 1139
1504 config SYSCTL_ARCH_UNALIGN_NO_WARN 1140 config SYSCTL_ARCH_UNALIGN_NO_WARN
1505 bool 1141 bool
1506 help 1142 help
1507 Enable support for /proc/sys/kernel 1143 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1508 Allows arch to define/use @no_unali 1144 Allows arch to define/use @no_unaligned_warning to possibly warn
1509 about unaligned access emulation go 1145 about unaligned access emulation going on under the hood.
1510 1146
1511 config SYSCTL_ARCH_UNALIGN_ALLOW 1147 config SYSCTL_ARCH_UNALIGN_ALLOW
1512 bool 1148 bool
1513 help 1149 help
1514 Enable support for /proc/sys/kernel 1150 Enable support for /proc/sys/kernel/unaligned-trap
1515 Allows arches to define/use @unalig 1151 Allows arches to define/use @unaligned_enabled to runtime toggle
1516 the unaligned access emulation. 1152 the unaligned access emulation.
1517 see arch/parisc/kernel/unaligned.c 1153 see arch/parisc/kernel/unaligned.c for reference
1518 1154
1519 config HAVE_PCSPKR_PLATFORM 1155 config HAVE_PCSPKR_PLATFORM
1520 bool 1156 bool
1521 1157
>> 1158 # interpreter that classic socket filters depend on
>> 1159 config BPF
>> 1160 bool
>> 1161
1522 menuconfig EXPERT 1162 menuconfig EXPERT
1523 bool "Configure standard kernel featu 1163 bool "Configure standard kernel features (expert users)"
1524 # Unhide debug options, to make the o 1164 # Unhide debug options, to make the on-by-default options visible
1525 select DEBUG_KERNEL 1165 select DEBUG_KERNEL
1526 help 1166 help
1527 This option allows certain base ker 1167 This option allows certain base kernel options and settings
1528 to be disabled or tweaked. This is !! 1168 to be disabled or tweaked. This is for specialized
1529 environments which can tolerate a " !! 1169 environments which can tolerate a "non-standard" kernel.
1530 Only use this if you really know wh !! 1170 Only use this if you really know what you are doing.
1531 1171
1532 config UID16 1172 config UID16
1533 bool "Enable 16-bit UID system calls" 1173 bool "Enable 16-bit UID system calls" if EXPERT
1534 depends on HAVE_UID16 && MULTIUSER 1174 depends on HAVE_UID16 && MULTIUSER
1535 default y 1175 default y
1536 help 1176 help
1537 This enables the legacy 16-bit UID 1177 This enables the legacy 16-bit UID syscall wrappers.
1538 1178
1539 config MULTIUSER 1179 config MULTIUSER
1540 bool "Multiple users, groups and capa 1180 bool "Multiple users, groups and capabilities support" if EXPERT
1541 default y 1181 default y
1542 help 1182 help
1543 This option enables support for non 1183 This option enables support for non-root users, groups and
1544 capabilities. 1184 capabilities.
1545 1185
1546 If you say N here, all processes wi 1186 If you say N here, all processes will run with UID 0, GID 0, and all
1547 possible capabilities. Saying N he 1187 possible capabilities. Saying N here also compiles out support for
1548 system calls related to UIDs, GIDs, 1188 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1549 setgid, and capset. 1189 setgid, and capset.
1550 1190
1551 If unsure, say Y here. 1191 If unsure, say Y here.
1552 1192
1553 config SGETMASK_SYSCALL 1193 config SGETMASK_SYSCALL
1554 bool "sgetmask/ssetmask syscalls supp 1194 bool "sgetmask/ssetmask syscalls support" if EXPERT
1555 default PARISC || M68K || PPC || MIPS !! 1195 def_bool PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH
1556 help !! 1196 ---help---
1557 sys_sgetmask and sys_ssetmask are o 1197 sys_sgetmask and sys_ssetmask are obsolete system calls
1558 no longer supported in libc but sti 1198 no longer supported in libc but still enabled by default in some
1559 architectures. 1199 architectures.
1560 1200
1561 If unsure, leave the default option 1201 If unsure, leave the default option here.
1562 1202
1563 config SYSFS_SYSCALL 1203 config SYSFS_SYSCALL
1564 bool "Sysfs syscall support" if EXPER 1204 bool "Sysfs syscall support" if EXPERT
1565 default y 1205 default y
1566 help !! 1206 ---help---
1567 sys_sysfs is an obsolete system cal 1207 sys_sysfs is an obsolete system call no longer supported in libc.
1568 Note that disabling this option is 1208 Note that disabling this option is more secure but might break
1569 compatibility with some systems. 1209 compatibility with some systems.
1570 1210
1571 If unsure say Y here. 1211 If unsure say Y here.
1572 1212
>> 1213 config SYSCTL_SYSCALL
>> 1214 bool "Sysctl syscall support" if EXPERT
>> 1215 depends on PROC_SYSCTL
>> 1216 default n
>> 1217 select SYSCTL
>> 1218 ---help---
>> 1219 sys_sysctl uses binary paths that have been found challenging
>> 1220 to properly maintain and use. The interface in /proc/sys
>> 1221 using paths with ascii names is now the primary path to this
>> 1222 information.
>> 1223
>> 1224 Almost nothing using the binary sysctl interface so if you are
>> 1225 trying to save some space it is probably safe to disable this,
>> 1226 making your kernel marginally smaller.
>> 1227
>> 1228 If unsure say N here.
>> 1229
1573 config FHANDLE 1230 config FHANDLE
1574 bool "open by fhandle syscalls" if EX 1231 bool "open by fhandle syscalls" if EXPERT
1575 select EXPORTFS 1232 select EXPORTFS
1576 default y 1233 default y
1577 help 1234 help
1578 If you say Y here, a user level pro 1235 If you say Y here, a user level program will be able to map
1579 file names to handle and then later 1236 file names to handle and then later use the handle for
1580 different file system operations. T 1237 different file system operations. This is useful in implementing
1581 userspace file servers, which now t 1238 userspace file servers, which now track files using handles instead
1582 of names. The handle would remain t 1239 of names. The handle would remain the same even if file names
1583 get renamed. Enables open_by_handle 1240 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
1584 syscalls. 1241 syscalls.
1585 1242
1586 config POSIX_TIMERS 1243 config POSIX_TIMERS
1587 bool "Posix Clocks & timers" if EXPER 1244 bool "Posix Clocks & timers" if EXPERT
1588 default y 1245 default y
1589 help 1246 help
1590 This includes native support for PO 1247 This includes native support for POSIX timers to the kernel.
1591 Some embedded systems have no use f 1248 Some embedded systems have no use for them and therefore they
1592 can be configured out to reduce the 1249 can be configured out to reduce the size of the kernel image.
1593 1250
1594 When this option is disabled, the f 1251 When this option is disabled, the following syscalls won't be
1595 available: timer_create, timer_gett 1252 available: timer_create, timer_gettime: timer_getoverrun,
1596 timer_settime, timer_delete, clock_ 1253 timer_settime, timer_delete, clock_adjtime, getitimer,
1597 setitimer, alarm. Furthermore, the 1254 setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
1598 clock_getres and clock_nanosleep sy 1255 clock_getres and clock_nanosleep syscalls will be limited to
1599 CLOCK_REALTIME, CLOCK_MONOTONIC and 1256 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
1600 1257
1601 If unsure say y. 1258 If unsure say y.
1602 1259
1603 config PRINTK 1260 config PRINTK
1604 default y 1261 default y
1605 bool "Enable support for printk" if E 1262 bool "Enable support for printk" if EXPERT
1606 select IRQ_WORK 1263 select IRQ_WORK
1607 help 1264 help
1608 This option enables normal printk s 1265 This option enables normal printk support. Removing it
1609 eliminates most of the message stri 1266 eliminates most of the message strings from the kernel image
1610 and makes the kernel more or less s 1267 and makes the kernel more or less silent. As this makes it
1611 very difficult to diagnose system p 1268 very difficult to diagnose system problems, saying N here is
1612 strongly discouraged. 1269 strongly discouraged.
1613 1270
>> 1271 config PRINTK_NMI
>> 1272 def_bool y
>> 1273 depends on PRINTK
>> 1274 depends on HAVE_NMI
>> 1275
1614 config BUG 1276 config BUG
1615 bool "BUG() support" if EXPERT 1277 bool "BUG() support" if EXPERT
1616 default y 1278 default y
1617 help 1279 help
1618 Disabling this option eliminates su !! 1280 Disabling this option eliminates support for BUG and WARN, reducing
1619 the size of your kernel image and p !! 1281 the size of your kernel image and potentially quietly ignoring
1620 numerous fatal conditions. You shou !! 1282 numerous fatal conditions. You should only consider disabling this
1621 option for embedded systems with no !! 1283 option for embedded systems with no facilities for reporting errors.
1622 Just say Y. !! 1284 Just say Y.
1623 1285
1624 config ELF_CORE 1286 config ELF_CORE
1625 depends on COREDUMP 1287 depends on COREDUMP
1626 default y 1288 default y
1627 bool "Enable ELF core dumps" if EXPER 1289 bool "Enable ELF core dumps" if EXPERT
1628 help 1290 help
1629 Enable support for generating core 1291 Enable support for generating core dumps. Disabling saves about 4k.
1630 1292
1631 1293
1632 config PCSPKR_PLATFORM 1294 config PCSPKR_PLATFORM
1633 bool "Enable PC-Speaker support" if E 1295 bool "Enable PC-Speaker support" if EXPERT
1634 depends on HAVE_PCSPKR_PLATFORM 1296 depends on HAVE_PCSPKR_PLATFORM
1635 select I8253_LOCK 1297 select I8253_LOCK
1636 default y 1298 default y
1637 help 1299 help
1638 This option allows to disable the i !! 1300 This option allows to disable the internal PC-Speaker
1639 support, saving some memory. !! 1301 support, saving some memory.
1640 1302
1641 config BASE_SMALL !! 1303 config BASE_FULL
1642 bool "Enable smaller-sized data struc !! 1304 default y
>> 1305 bool "Enable full-sized data structures for core" if EXPERT
1643 help 1306 help
1644 Enabling this option reduces the si !! 1307 Disabling this option reduces the size of miscellaneous core
1645 kernel data structures. This saves 1308 kernel data structures. This saves memory on small machines,
1646 but may reduce performance. 1309 but may reduce performance.
1647 1310
1648 config FUTEX 1311 config FUTEX
1649 bool "Enable futex support" if EXPERT 1312 bool "Enable futex support" if EXPERT
1650 depends on !(SPARC32 && SMP) <<
1651 default y 1313 default y
1652 imply RT_MUTEXES 1314 imply RT_MUTEXES
1653 help 1315 help
1654 Disabling this option will cause th 1316 Disabling this option will cause the kernel to be built without
1655 support for "fast userspace mutexes 1317 support for "fast userspace mutexes". The resulting kernel may not
1656 run glibc-based applications correc 1318 run glibc-based applications correctly.
1657 1319
1658 config FUTEX_PI 1320 config FUTEX_PI
1659 bool 1321 bool
1660 depends on FUTEX && RT_MUTEXES 1322 depends on FUTEX && RT_MUTEXES
1661 default y 1323 default y
1662 1324
>> 1325 config HAVE_FUTEX_CMPXCHG
>> 1326 bool
>> 1327 depends on FUTEX
>> 1328 help
>> 1329 Architectures should select this if futex_atomic_cmpxchg_inatomic()
>> 1330 is implemented and always working. This removes a couple of runtime
>> 1331 checks.
>> 1332
1663 config EPOLL 1333 config EPOLL
1664 bool "Enable eventpoll support" if EX 1334 bool "Enable eventpoll support" if EXPERT
1665 default y 1335 default y
>> 1336 select ANON_INODES
1666 help 1337 help
1667 Disabling this option will cause th 1338 Disabling this option will cause the kernel to be built without
1668 support for epoll family of system 1339 support for epoll family of system calls.
1669 1340
1670 config SIGNALFD 1341 config SIGNALFD
1671 bool "Enable signalfd() system call" 1342 bool "Enable signalfd() system call" if EXPERT
>> 1343 select ANON_INODES
1672 default y 1344 default y
1673 help 1345 help
1674 Enable the signalfd() system call t 1346 Enable the signalfd() system call that allows to receive signals
1675 on a file descriptor. 1347 on a file descriptor.
1676 1348
1677 If unsure, say Y. 1349 If unsure, say Y.
1678 1350
1679 config TIMERFD 1351 config TIMERFD
1680 bool "Enable timerfd() system call" i 1352 bool "Enable timerfd() system call" if EXPERT
>> 1353 select ANON_INODES
1681 default y 1354 default y
1682 help 1355 help
1683 Enable the timerfd() system call th 1356 Enable the timerfd() system call that allows to receive timer
1684 events on a file descriptor. 1357 events on a file descriptor.
1685 1358
1686 If unsure, say Y. 1359 If unsure, say Y.
1687 1360
1688 config EVENTFD 1361 config EVENTFD
1689 bool "Enable eventfd() system call" i 1362 bool "Enable eventfd() system call" if EXPERT
>> 1363 select ANON_INODES
1690 default y 1364 default y
1691 help 1365 help
1692 Enable the eventfd() system call th 1366 Enable the eventfd() system call that allows to receive both
1693 kernel notification (ie. KAIO) or u 1367 kernel notification (ie. KAIO) or userspace notifications.
1694 1368
1695 If unsure, say Y. 1369 If unsure, say Y.
1696 1370
1697 config SHMEM 1371 config SHMEM
1698 bool "Use full shmem filesystem" if E 1372 bool "Use full shmem filesystem" if EXPERT
1699 default y 1373 default y
1700 depends on MMU 1374 depends on MMU
1701 help 1375 help
1702 The shmem is an internal filesystem 1376 The shmem is an internal filesystem used to manage shared memory.
1703 It is backed by swap and manages re 1377 It is backed by swap and manages resource limits. It is also exported
1704 to userspace as tmpfs if TMPFS is e 1378 to userspace as tmpfs if TMPFS is enabled. Disabling this
1705 option replaces shmem and tmpfs wit 1379 option replaces shmem and tmpfs with the much simpler ramfs code,
1706 which may be appropriate on small s 1380 which may be appropriate on small systems without swap.
1707 1381
1708 config AIO 1382 config AIO
1709 bool "Enable AIO support" if EXPERT 1383 bool "Enable AIO support" if EXPERT
1710 default y 1384 default y
1711 help 1385 help
1712 This option enables POSIX asynchron 1386 This option enables POSIX asynchronous I/O which may by used
1713 by some high performance threaded a 1387 by some high performance threaded applications. Disabling
1714 this option saves about 7k. 1388 this option saves about 7k.
1715 1389
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 1390 config ADVISE_SYSCALLS
1739 bool "Enable madvise/fadvise syscalls 1391 bool "Enable madvise/fadvise syscalls" if EXPERT
1740 default y 1392 default y
1741 help 1393 help
1742 This option enables the madvise and 1394 This option enables the madvise and fadvise syscalls, used by
1743 applications to advise the kernel a 1395 applications to advise the kernel about their future memory or file
1744 usage, improving performance. If bu 1396 usage, improving performance. If building an embedded system where no
1745 applications use these syscalls, yo 1397 applications use these syscalls, you can disable this option to save
1746 space. 1398 space.
1747 1399
1748 config MEMBARRIER 1400 config MEMBARRIER
1749 bool "Enable membarrier() system call 1401 bool "Enable membarrier() system call" if EXPERT
1750 default y 1402 default y
1751 help 1403 help
1752 Enable the membarrier() system call 1404 Enable the membarrier() system call that allows issuing memory
1753 barriers across all running threads 1405 barriers across all running threads, which can be used to distribute
1754 the cost of user-space memory barri 1406 the cost of user-space memory barriers asymmetrically by transforming
1755 pairs of memory barriers into pairs 1407 pairs of memory barriers into pairs consisting of membarrier() and a
1756 compiler barrier. 1408 compiler barrier.
1757 1409
1758 If unsure, say Y. 1410 If unsure, say Y.
1759 1411
1760 config KCMP !! 1412 config KALLSYMS
1761 bool "Enable kcmp() system call" if E !! 1413 bool "Load all symbols for debugging/ksymoops" if EXPERT
>> 1414 default y
>> 1415 help
>> 1416 Say Y here to let the kernel print out symbolic crash information and
>> 1417 symbolic stack backtraces. This increases the size of the kernel
>> 1418 somewhat, as all symbols have to be loaded into the kernel image.
>> 1419
>> 1420 config KALLSYMS_ALL
>> 1421 bool "Include all symbols in kallsyms"
>> 1422 depends on DEBUG_KERNEL && KALLSYMS
1762 help 1423 help
1763 Enable the kernel resource comparis !! 1424 Normally kallsyms only contains the symbols of functions for nicer
1764 user-space with the ability to comp !! 1425 OOPS messages and backtraces (i.e., symbols from the text and inittext
1765 share a common resource, such as a !! 1426 sections). This is sufficient for most cases. And only in very rare
1766 memory space. !! 1427 cases (e.g., when a debugger is used) all symbols are required (e.g.,
>> 1428 names of variables from the data sections, etc).
>> 1429
>> 1430 This option makes sure that all symbols are loaded into the kernel
>> 1431 image (i.e., symbols from all sections) in cost of increased kernel
>> 1432 size (depending on the kernel configuration, it may be 300KiB or
>> 1433 something like this).
1767 1434
1768 If unsure, say N. !! 1435 Say N unless you really need all symbols.
>> 1436
>> 1437 config KALLSYMS_ABSOLUTE_PERCPU
>> 1438 bool
>> 1439 depends on KALLSYMS
>> 1440 default X86_64 && SMP
>> 1441
>> 1442 config KALLSYMS_BASE_RELATIVE
>> 1443 bool
>> 1444 depends on KALLSYMS
>> 1445 default !IA64
>> 1446 help
>> 1447 Instead of emitting them as absolute values in the native word size,
>> 1448 emit the symbol references in the kallsyms table as 32-bit entries,
>> 1449 each containing a relative value in the range [base, base + U32_MAX]
>> 1450 or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either
>> 1451 an absolute value in the range [0, S32_MAX] or a relative value in the
>> 1452 range [base, base + S32_MAX], where base is the lowest relative symbol
>> 1453 address encountered in the image.
>> 1454
>> 1455 On 64-bit builds, this reduces the size of the address table by 50%,
>> 1456 but more importantly, it results in entries whose values are build
>> 1457 time constants, and no relocation pass is required at runtime to fix
>> 1458 up the entries based on the runtime load address of the kernel.
>> 1459
>> 1460 # end of the "standard kernel features (expert users)" menu
>> 1461
>> 1462 # syscall, maps, verifier
>> 1463 config BPF_SYSCALL
>> 1464 bool "Enable bpf() system call"
>> 1465 select ANON_INODES
>> 1466 select BPF
>> 1467 select IRQ_WORK
>> 1468 default n
>> 1469 help
>> 1470 Enable the bpf() system call that allows to manipulate eBPF
>> 1471 programs and maps via file descriptors.
>> 1472
>> 1473 config BPF_JIT_ALWAYS_ON
>> 1474 bool "Permanently enable BPF JIT and remove BPF interpreter"
>> 1475 depends on BPF_SYSCALL && HAVE_EBPF_JIT && BPF_JIT
>> 1476 help
>> 1477 Enables BPF JIT and removes BPF interpreter to avoid
>> 1478 speculative execution of BPF instructions by the interpreter
>> 1479
>> 1480 config BPF_UNPRIV_DEFAULT_OFF
>> 1481 bool "Disable unprivileged BPF by default"
>> 1482 depends on BPF_SYSCALL
>> 1483 help
>> 1484 Disables unprivileged BPF by default by setting the corresponding
>> 1485 /proc/sys/kernel/unprivileged_bpf_disabled knob to 2. An admin can
>> 1486 still reenable it by setting it to 0 later on, or permanently
>> 1487 disable it by setting it to 1 (from which no other transition to
>> 1488 0 is possible anymore).
>> 1489
>> 1490 config USERFAULTFD
>> 1491 bool "Enable userfaultfd() system call"
>> 1492 select ANON_INODES
>> 1493 depends on MMU
>> 1494 help
>> 1495 Enable the userfaultfd() system call that allows to intercept and
>> 1496 handle page faults in userland.
>> 1497
>> 1498 config ARCH_HAS_MEMBARRIER_CALLBACKS
>> 1499 bool
>> 1500
>> 1501 config ARCH_HAS_MEMBARRIER_SYNC_CORE
>> 1502 bool
1769 1503
1770 config RSEQ 1504 config RSEQ
1771 bool "Enable rseq() system call" if E 1505 bool "Enable rseq() system call" if EXPERT
1772 default y 1506 default y
1773 depends on HAVE_RSEQ 1507 depends on HAVE_RSEQ
1774 select MEMBARRIER 1508 select MEMBARRIER
1775 help 1509 help
1776 Enable the restartable sequences sy 1510 Enable the restartable sequences system call. It provides a
1777 user-space cache for the current CP 1511 user-space cache for the current CPU number value, which
1778 speeds up getting the current CPU n 1512 speeds up getting the current CPU number from user-space,
1779 as well as an ABI to speed up user- 1513 as well as an ABI to speed up user-space operations on
1780 per-CPU data. 1514 per-CPU data.
1781 1515
1782 If unsure, say Y. 1516 If unsure, say Y.
1783 1517
1784 config DEBUG_RSEQ 1518 config DEBUG_RSEQ
1785 default n 1519 default n
1786 bool "Enable debugging of rseq() syst !! 1520 bool "Enabled debugging of rseq() system call" if EXPERT
1787 depends on RSEQ && DEBUG_KERNEL 1521 depends on RSEQ && DEBUG_KERNEL
1788 help 1522 help
1789 Enable extra debugging checks for t 1523 Enable extra debugging checks for the rseq system call.
1790 1524
1791 If unsure, say N. 1525 If unsure, say N.
1792 1526
1793 config CACHESTAT_SYSCALL !! 1527 config EMBEDDED
1794 bool "Enable cachestat() system call" !! 1528 bool "Embedded system"
1795 default y !! 1529 option allnoconfig_y
1796 help !! 1530 select EXPERT
1797 Enable the cachestat system call, w !! 1531 help
1798 statistics of a file (number of cac !! 1532 This option should be enabled if compiling the kernel for
1799 pages marked for writeback, (recent !! 1533 an embedded system so certain expert options are available
1800 !! 1534 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 1535
1862 config HAVE_PERF_EVENTS 1536 config HAVE_PERF_EVENTS
1863 bool 1537 bool
1864 help 1538 help
1865 See tools/perf/design.txt for detai 1539 See tools/perf/design.txt for details.
1866 1540
1867 config GUEST_PERF_EVENTS <<
1868 bool <<
1869 depends on HAVE_PERF_EVENTS <<
1870 <<
1871 config PERF_USE_VMALLOC 1541 config PERF_USE_VMALLOC
1872 bool 1542 bool
1873 help 1543 help
1874 See tools/perf/design.txt for detai 1544 See tools/perf/design.txt for details
1875 1545
>> 1546 config PC104
>> 1547 bool "PC/104 support" if EXPERT
>> 1548 help
>> 1549 Expose PC/104 form factor device drivers and options available for
>> 1550 selection and configuration. Enable this option if your target
>> 1551 machine has a PC/104 bus.
>> 1552
1876 menu "Kernel Performance Events And Counters" 1553 menu "Kernel Performance Events And Counters"
1877 1554
1878 config PERF_EVENTS 1555 config PERF_EVENTS
1879 bool "Kernel performance events and c 1556 bool "Kernel performance events and counters"
1880 default y if PROFILING 1557 default y if PROFILING
1881 depends on HAVE_PERF_EVENTS 1558 depends on HAVE_PERF_EVENTS
>> 1559 select ANON_INODES
1882 select IRQ_WORK 1560 select IRQ_WORK
>> 1561 select SRCU
1883 help 1562 help
1884 Enable kernel support for various p 1563 Enable kernel support for various performance events provided
1885 by software and hardware. 1564 by software and hardware.
1886 1565
1887 Software events are supported eithe 1566 Software events are supported either built-in or via the
1888 use of generic tracepoints. 1567 use of generic tracepoints.
1889 1568
1890 Most modern CPUs support performanc 1569 Most modern CPUs support performance events via performance
1891 counter registers. These registers 1570 counter registers. These registers count the number of certain
1892 types of hw events: such as instruc 1571 types of hw events: such as instructions executed, cachemisses
1893 suffered, or branches mis-predicted 1572 suffered, or branches mis-predicted - without slowing down the
1894 kernel or applications. These regis 1573 kernel or applications. These registers can also trigger interrupts
1895 when a threshold number of events h 1574 when a threshold number of events have passed - and can thus be
1896 used to profile the code that runs 1575 used to profile the code that runs on that CPU.
1897 1576
1898 The Linux Performance Event subsyst 1577 The Linux Performance Event subsystem provides an abstraction of
1899 these software and hardware event c 1578 these software and hardware event capabilities, available via a
1900 system call and used by the "perf" 1579 system call and used by the "perf" utility in tools/perf/. It
1901 provides per task and per CPU count 1580 provides per task and per CPU counters, and it provides event
1902 capabilities on top of those. 1581 capabilities on top of those.
1903 1582
1904 Say Y if unsure. 1583 Say Y if unsure.
1905 1584
1906 config DEBUG_PERF_USE_VMALLOC 1585 config DEBUG_PERF_USE_VMALLOC
1907 default n 1586 default n
1908 bool "Debug: use vmalloc to back perf 1587 bool "Debug: use vmalloc to back perf mmap() buffers"
1909 depends on PERF_EVENTS && DEBUG_KERNE 1588 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
1910 select PERF_USE_VMALLOC 1589 select PERF_USE_VMALLOC
1911 help 1590 help
1912 Use vmalloc memory to back perf mma !! 1591 Use vmalloc memory to back perf mmap() buffers.
1913 1592
1914 Mostly useful for debugging the vma !! 1593 Mostly useful for debugging the vmalloc code on platforms
1915 that don't require it. !! 1594 that don't require it.
1916 1595
1917 Say N if unsure. !! 1596 Say N if unsure.
1918 1597
1919 endmenu 1598 endmenu
1920 1599
>> 1600 config VM_EVENT_COUNTERS
>> 1601 default y
>> 1602 bool "Enable VM event counters for /proc/vmstat" if EXPERT
>> 1603 help
>> 1604 VM event counters are needed for event counts to be shown.
>> 1605 This option allows the disabling of the VM event counters
>> 1606 on EXPERT systems. /proc/vmstat will only show page counts
>> 1607 if VM event counters are disabled.
>> 1608
>> 1609 config SLUB_DEBUG
>> 1610 default y
>> 1611 bool "Enable SLUB debugging support" if EXPERT
>> 1612 depends on SLUB && SYSFS
>> 1613 help
>> 1614 SLUB has extensive debug support features. Disabling these can
>> 1615 result in significant savings in code size. This also disables
>> 1616 SLUB sysfs support. /sys/slab will not exist and there will be
>> 1617 no support for cache validation etc.
>> 1618
>> 1619 config SLUB_MEMCG_SYSFS_ON
>> 1620 default n
>> 1621 bool "Enable memcg SLUB sysfs support by default" if EXPERT
>> 1622 depends on SLUB && SYSFS && MEMCG
>> 1623 help
>> 1624 SLUB creates a directory under /sys/kernel/slab for each
>> 1625 allocation cache to host info and debug files. If memory
>> 1626 cgroup is enabled, each cache can have per memory cgroup
>> 1627 caches. SLUB can create the same sysfs directories for these
>> 1628 caches under /sys/kernel/slab/CACHE/cgroup but it can lead
>> 1629 to a very high number of debug files being created. This is
>> 1630 controlled by slub_memcg_sysfs boot parameter and this
>> 1631 config option determines the parameter's default value.
>> 1632
>> 1633 config COMPAT_BRK
>> 1634 bool "Disable heap randomization"
>> 1635 default y
>> 1636 help
>> 1637 Randomizing heap placement makes heap exploits harder, but it
>> 1638 also breaks ancient binaries (including anything libc5 based).
>> 1639 This option changes the bootup default to heap randomization
>> 1640 disabled, and can be overridden at runtime by setting
>> 1641 /proc/sys/kernel/randomize_va_space to 2.
>> 1642
>> 1643 On non-ancient distros (post-2000 ones) N is usually a safe choice.
>> 1644
>> 1645 choice
>> 1646 prompt "Choose SLAB allocator"
>> 1647 default SLUB
>> 1648 help
>> 1649 This option allows to select a slab allocator.
>> 1650
>> 1651 config SLAB
>> 1652 bool "SLAB"
>> 1653 select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 1654 help
>> 1655 The regular slab allocator that is established and known to work
>> 1656 well in all environments. It organizes cache hot objects in
>> 1657 per cpu and per node queues.
>> 1658
>> 1659 config SLUB
>> 1660 bool "SLUB (Unqueued Allocator)"
>> 1661 select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 1662 help
>> 1663 SLUB is a slab allocator that minimizes cache line usage
>> 1664 instead of managing queues of cached objects (SLAB approach).
>> 1665 Per cpu caching is realized using slabs of objects instead
>> 1666 of queues of objects. SLUB can use memory efficiently
>> 1667 and has enhanced diagnostics. SLUB is the default choice for
>> 1668 a slab allocator.
>> 1669
>> 1670 config SLOB
>> 1671 depends on EXPERT
>> 1672 bool "SLOB (Simple Allocator)"
>> 1673 help
>> 1674 SLOB replaces the stock allocator with a drastically simpler
>> 1675 allocator. SLOB is generally more space efficient but
>> 1676 does not perform as well on large systems.
>> 1677
>> 1678 endchoice
>> 1679
>> 1680 config SLAB_MERGE_DEFAULT
>> 1681 bool "Allow slab caches to be merged"
>> 1682 default y
>> 1683 help
>> 1684 For reduced kernel memory fragmentation, slab caches can be
>> 1685 merged when they share the same size and other characteristics.
>> 1686 This carries a risk of kernel heap overflows being able to
>> 1687 overwrite objects from merged caches (and more easily control
>> 1688 cache layout), which makes such heap attacks easier to exploit
>> 1689 by attackers. By keeping caches unmerged, these kinds of exploits
>> 1690 can usually only damage objects in the same cache. To disable
>> 1691 merging at runtime, "slab_nomerge" can be passed on the kernel
>> 1692 command line.
>> 1693
>> 1694 config SLAB_FREELIST_RANDOM
>> 1695 default n
>> 1696 depends on SLAB || SLUB
>> 1697 bool "SLAB freelist randomization"
>> 1698 help
>> 1699 Randomizes the freelist order used on creating new pages. This
>> 1700 security feature reduces the predictability of the kernel slab
>> 1701 allocator against heap overflows.
>> 1702
>> 1703 config SLAB_FREELIST_HARDENED
>> 1704 bool "Harden slab freelist metadata"
>> 1705 depends on SLUB
>> 1706 help
>> 1707 Many kernel heap attacks try to target slab cache metadata and
>> 1708 other infrastructure. This options makes minor performance
>> 1709 sacrifies to harden the kernel slab allocator against common
>> 1710 freelist exploit methods.
>> 1711
>> 1712 config SLUB_CPU_PARTIAL
>> 1713 default y
>> 1714 depends on SLUB && SMP
>> 1715 bool "SLUB per cpu partial cache"
>> 1716 help
>> 1717 Per cpu partial caches accellerate objects allocation and freeing
>> 1718 that is local to a processor at the price of more indeterminism
>> 1719 in the latency of the free. On overflow these caches will be cleared
>> 1720 which requires the taking of locks that may cause latency spikes.
>> 1721 Typically one would choose no for a realtime system.
>> 1722
>> 1723 config MMAP_ALLOW_UNINITIALIZED
>> 1724 bool "Allow mmapped anonymous memory to be uninitialized"
>> 1725 depends on EXPERT && !MMU
>> 1726 default n
>> 1727 help
>> 1728 Normally, and according to the Linux spec, anonymous memory obtained
>> 1729 from mmap() has its contents cleared before it is passed to
>> 1730 userspace. Enabling this config option allows you to request that
>> 1731 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
>> 1732 providing a huge performance boost. If this option is not enabled,
>> 1733 then the flag will be ignored.
>> 1734
>> 1735 This is taken advantage of by uClibc's malloc(), and also by
>> 1736 ELF-FDPIC binfmt's brk and stack allocator.
>> 1737
>> 1738 Because of the obvious security issues, this option should only be
>> 1739 enabled on embedded devices where you control what is run in
>> 1740 userspace. Since that isn't generally a problem on no-MMU systems,
>> 1741 it is normally safe to say Y here.
>> 1742
>> 1743 See Documentation/nommu-mmap.txt for more information.
>> 1744
1921 config SYSTEM_DATA_VERIFICATION 1745 config SYSTEM_DATA_VERIFICATION
1922 def_bool n 1746 def_bool n
1923 select SYSTEM_TRUSTED_KEYRING 1747 select SYSTEM_TRUSTED_KEYRING
1924 select KEYS 1748 select KEYS
1925 select CRYPTO 1749 select CRYPTO
1926 select CRYPTO_RSA 1750 select CRYPTO_RSA
1927 select ASYMMETRIC_KEY_TYPE 1751 select ASYMMETRIC_KEY_TYPE
1928 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 1752 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1929 select ASN1 1753 select ASN1
1930 select OID_REGISTRY 1754 select OID_REGISTRY
1931 select X509_CERTIFICATE_PARSER 1755 select X509_CERTIFICATE_PARSER
1932 select PKCS7_MESSAGE_PARSER 1756 select PKCS7_MESSAGE_PARSER
1933 help 1757 help
1934 Provide PKCS#7 message verification 1758 Provide PKCS#7 message verification using the contents of the system
1935 trusted keyring to provide public k 1759 trusted keyring to provide public keys. This then can be used for
1936 module verification, kexec image ve 1760 module verification, kexec image verification and firmware blob
1937 verification. 1761 verification.
1938 1762
1939 config PROFILING 1763 config PROFILING
1940 bool "Profiling support" 1764 bool "Profiling support"
1941 help 1765 help
1942 Say Y here to enable the extended p 1766 Say Y here to enable the extended profiling support mechanisms used
1943 by profilers. !! 1767 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 1768
1986 # 1769 #
1987 # Place an empty function call at each tracep 1770 # Place an empty function call at each tracepoint site. Can be
1988 # dynamically changed for a probe function. 1771 # dynamically changed for a probe function.
1989 # 1772 #
1990 config TRACEPOINTS 1773 config TRACEPOINTS
1991 bool 1774 bool
1992 1775
1993 source "kernel/Kconfig.kexec" <<
1994 <<
1995 endmenu # General setup 1776 endmenu # General setup
1996 1777
1997 source "arch/Kconfig" 1778 source "arch/Kconfig"
1998 1779
1999 config RT_MUTEXES 1780 config RT_MUTEXES
2000 bool 1781 bool
2001 default y if PREEMPT_RT <<
2002 1782
2003 config MODULE_SIG_FORMAT !! 1783 config BASE_SMALL
2004 def_bool n !! 1784 int
>> 1785 default 0 if BASE_FULL
>> 1786 default 1 if !BASE_FULL
>> 1787
>> 1788 menuconfig MODULES
>> 1789 bool "Enable loadable module support"
>> 1790 option modules
>> 1791 help
>> 1792 Kernel modules are small pieces of compiled code which can
>> 1793 be inserted in the running kernel, rather than being
>> 1794 permanently built into the kernel. You use the "modprobe"
>> 1795 tool to add (and sometimes remove) them. If you say Y here,
>> 1796 many parts of the kernel can be built as modules (by
>> 1797 answering M instead of Y where indicated): this is most
>> 1798 useful for infrequently used options which are not required
>> 1799 for booting. For more information, see the man pages for
>> 1800 modprobe, lsmod, modinfo, insmod and rmmod.
>> 1801
>> 1802 If you say Y here, you will need to run "make
>> 1803 modules_install" to put the modules under /lib/modules/
>> 1804 where modprobe can find them (you may need to be root to do
>> 1805 this).
>> 1806
>> 1807 If unsure, say Y.
>> 1808
>> 1809 if MODULES
>> 1810
>> 1811 config MODULE_FORCE_LOAD
>> 1812 bool "Forced module loading"
>> 1813 default n
>> 1814 help
>> 1815 Allow loading of modules without version information (ie. modprobe
>> 1816 --force). Forced module loading sets the 'F' (forced) taint flag and
>> 1817 is usually a really bad idea.
>> 1818
>> 1819 config MODULE_UNLOAD
>> 1820 bool "Module unloading"
>> 1821 help
>> 1822 Without this option you will not be able to unload any
>> 1823 modules (note that some modules may not be unloadable
>> 1824 anyway), which makes your kernel smaller, faster
>> 1825 and simpler. If unsure, say Y.
>> 1826
>> 1827 config MODULE_FORCE_UNLOAD
>> 1828 bool "Forced module unloading"
>> 1829 depends on MODULE_UNLOAD
>> 1830 help
>> 1831 This option allows you to force a module to unload, even if the
>> 1832 kernel believes it is unsafe: the kernel will remove the module
>> 1833 without waiting for anyone to stop using it (using the -f option to
>> 1834 rmmod). This is mainly for kernel developers and desperate users.
>> 1835 If unsure, say N.
>> 1836
>> 1837 config MODVERSIONS
>> 1838 bool "Module versioning support"
>> 1839 help
>> 1840 Usually, you have to use modules compiled with your kernel.
>> 1841 Saying Y here makes it sometimes possible to use modules
>> 1842 compiled for different kernels, by adding enough information
>> 1843 to the modules to (hopefully) spot any changes which would
>> 1844 make them incompatible with the kernel you are running. If
>> 1845 unsure, say N.
>> 1846
>> 1847 config MODULE_REL_CRCS
>> 1848 bool
>> 1849 depends on MODVERSIONS
>> 1850
>> 1851 config MODULE_SRCVERSION_ALL
>> 1852 bool "Source checksum for all modules"
>> 1853 help
>> 1854 Modules which contain a MODULE_VERSION get an extra "srcversion"
>> 1855 field inserted into their modinfo section, which contains a
>> 1856 sum of the source files which made it. This helps maintainers
>> 1857 see exactly which source was used to build a module (since
>> 1858 others sometimes change the module source without updating
>> 1859 the version). With this option, such a "srcversion" field
>> 1860 will be created for all modules. If unsure, say N.
>> 1861
>> 1862 config MODULE_SIG
>> 1863 bool "Module signature verification"
>> 1864 depends on MODULES
2005 select SYSTEM_DATA_VERIFICATION 1865 select SYSTEM_DATA_VERIFICATION
>> 1866 help
>> 1867 Check modules for valid signatures upon load: the signature
>> 1868 is simply appended to the module. For more information see
>> 1869 <file:Documentation/admin-guide/module-signing.rst>.
>> 1870
>> 1871 Note that this option adds the OpenSSL development packages as a
>> 1872 kernel build dependency so that the signing tool can use its crypto
>> 1873 library.
>> 1874
>> 1875 !!!WARNING!!! If you enable this option, you MUST make sure that the
>> 1876 module DOES NOT get stripped after being signed. This includes the
>> 1877 debuginfo strip done by some packagers (such as rpmbuild) and
>> 1878 inclusion into an initramfs that wants the module size reduced.
>> 1879
>> 1880 config MODULE_SIG_FORCE
>> 1881 bool "Require modules to be validly signed"
>> 1882 depends on MODULE_SIG
>> 1883 help
>> 1884 Reject unsigned modules or signed modules for which we don't have a
>> 1885 key. Without this, such modules will simply taint the kernel.
>> 1886
>> 1887 config MODULE_SIG_ALL
>> 1888 bool "Automatically sign all modules"
>> 1889 default y
>> 1890 depends on MODULE_SIG
>> 1891 help
>> 1892 Sign all modules during make modules_install. Without this option,
>> 1893 modules must be signed manually, using the scripts/sign-file tool.
>> 1894
>> 1895 comment "Do not forget to sign required modules with scripts/sign-file"
>> 1896 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
>> 1897
>> 1898 choice
>> 1899 prompt "Which hash algorithm should modules be signed with?"
>> 1900 depends on MODULE_SIG
>> 1901 help
>> 1902 This determines which sort of hashing algorithm will be used during
>> 1903 signature generation. This algorithm _must_ be built into the kernel
>> 1904 directly so that signature verification can take place. It is not
>> 1905 possible to load a signed module containing the algorithm to check
>> 1906 the signature on that module.
>> 1907
>> 1908 config MODULE_SIG_SHA1
>> 1909 bool "Sign modules with SHA-1"
>> 1910 select CRYPTO_SHA1
>> 1911
>> 1912 config MODULE_SIG_SHA224
>> 1913 bool "Sign modules with SHA-224"
>> 1914 select CRYPTO_SHA256
>> 1915
>> 1916 config MODULE_SIG_SHA256
>> 1917 bool "Sign modules with SHA-256"
>> 1918 select CRYPTO_SHA256
>> 1919
>> 1920 config MODULE_SIG_SHA384
>> 1921 bool "Sign modules with SHA-384"
>> 1922 select CRYPTO_SHA512
>> 1923
>> 1924 config MODULE_SIG_SHA512
>> 1925 bool "Sign modules with SHA-512"
>> 1926 select CRYPTO_SHA512
>> 1927
>> 1928 endchoice
>> 1929
>> 1930 config MODULE_SIG_HASH
>> 1931 string
>> 1932 depends on MODULE_SIG
>> 1933 default "sha1" if MODULE_SIG_SHA1
>> 1934 default "sha224" if MODULE_SIG_SHA224
>> 1935 default "sha256" if MODULE_SIG_SHA256
>> 1936 default "sha384" if MODULE_SIG_SHA384
>> 1937 default "sha512" if MODULE_SIG_SHA512
>> 1938
>> 1939 config MODULE_COMPRESS
>> 1940 bool "Compress modules on installation"
>> 1941 depends on MODULES
>> 1942 help
>> 1943
>> 1944 Compresses kernel modules when 'make modules_install' is run; gzip or
>> 1945 xz depending on "Compression algorithm" below.
2006 1946
2007 source "kernel/module/Kconfig" !! 1947 module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
>> 1948
>> 1949 Out-of-tree kernel modules installed using Kbuild will also be
>> 1950 compressed upon installation.
>> 1951
>> 1952 Note: for modules inside an initrd or initramfs, it's more efficient
>> 1953 to compress the whole initrd or initramfs instead.
>> 1954
>> 1955 Note: This is fully compatible with signed modules.
>> 1956
>> 1957 If in doubt, say N.
>> 1958
>> 1959 choice
>> 1960 prompt "Compression algorithm"
>> 1961 depends on MODULE_COMPRESS
>> 1962 default MODULE_COMPRESS_GZIP
>> 1963 help
>> 1964 This determines which sort of compression will be used during
>> 1965 'make modules_install'.
>> 1966
>> 1967 GZIP (default) and XZ are supported.
>> 1968
>> 1969 config MODULE_COMPRESS_GZIP
>> 1970 bool "GZIP"
>> 1971
>> 1972 config MODULE_COMPRESS_XZ
>> 1973 bool "XZ"
>> 1974
>> 1975 endchoice
>> 1976
>> 1977 config TRIM_UNUSED_KSYMS
>> 1978 bool "Trim unused exported kernel symbols"
>> 1979 depends on MODULES && !UNUSED_SYMBOLS
>> 1980 help
>> 1981 The kernel and some modules make many symbols available for
>> 1982 other modules to use via EXPORT_SYMBOL() and variants. Depending
>> 1983 on the set of modules being selected in your kernel configuration,
>> 1984 many of those exported symbols might never be used.
>> 1985
>> 1986 This option allows for unused exported symbols to be dropped from
>> 1987 the build. In turn, this provides the compiler more opportunities
>> 1988 (especially when using LTO) for optimizing the code and reducing
>> 1989 binary size. This might have some security advantages as well.
>> 1990
>> 1991 If unsure, or if you need to build out-of-tree modules, say N.
>> 1992
>> 1993 endif # MODULES
>> 1994
>> 1995 config MODULES_TREE_LOOKUP
>> 1996 def_bool y
>> 1997 depends on PERF_EVENTS || TRACING
2008 1998
2009 config INIT_ALL_POSSIBLE 1999 config INIT_ALL_POSSIBLE
2010 bool 2000 bool
2011 help 2001 help
2012 Back when each arch used to define 2002 Back when each arch used to define their own cpu_online_mask and
2013 cpu_possible_mask, some of them cho 2003 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
2014 with all 1s, and others with all 0s 2004 with all 1s, and others with all 0s. When they were centralised,
2015 it was better to provide this optio 2005 it was better to provide this option than to break all the archs
2016 and have several arch maintainers p 2006 and have several arch maintainers pursuing me down dark alleys.
2017 2007
2018 source "block/Kconfig" 2008 source "block/Kconfig"
2019 2009
2020 config PREEMPT_NOTIFIERS 2010 config PREEMPT_NOTIFIERS
2021 bool 2011 bool
2022 2012
2023 config PADATA 2013 config PADATA
2024 depends on SMP 2014 depends on SMP
2025 bool 2015 bool
2026 2016
2027 config ASN1 2017 config ASN1
2028 tristate 2018 tristate
2029 help 2019 help
2030 Build a simple ASN.1 grammar compil 2020 Build a simple ASN.1 grammar compiler that produces a bytecode output
2031 that can be interpreted by the ASN. 2021 that can be interpreted by the ASN.1 stream decoder and used to
2032 inform it as to what tags are to be 2022 inform it as to what tags are to be expected in a stream and what
2033 functions to call on what tags. 2023 functions to call on what tags.
2034 2024
2035 source "kernel/Kconfig.locks" 2025 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 2026
2043 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2027 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
2044 bool 2028 bool
2045 2029
2046 # It may be useful for an architecture to ove 2030 # It may be useful for an architecture to override the definitions of the
2047 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() ma 2031 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h>
2048 # and the COMPAT_ variants in <linux/compat.h 2032 # and the COMPAT_ variants in <linux/compat.h>, in particular to use a
2049 # different calling convention for syscalls. 2033 # different calling convention for syscalls. They can also override the
2050 # macros for not-implemented syscalls in kern 2034 # macros for not-implemented syscalls in kernel/sys_ni.c and
2051 # kernel/time/posix-stubs.c. All these overri 2035 # kernel/time/posix-stubs.c. All these overrides need to be available in
2052 # <asm/syscall_wrapper.h>. 2036 # <asm/syscall_wrapper.h>.
2053 config ARCH_HAS_SYSCALL_WRAPPER 2037 config ARCH_HAS_SYSCALL_WRAPPER
2054 def_bool n 2038 def_bool n
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