1 # SPDX-License-Identifier: GPL-2.0-only !! 1 config ARCH
2 config CC_VERSION_TEXT <<
3 string 2 string
4 default "$(CC_VERSION_TEXT)" !! 3 option env="ARCH"
5 help <<
6 This is used in unclear ways: <<
7 <<
8 - Re-run Kconfig when the compiler i <<
9 The 'default' property references <<
10 CC_VERSION_TEXT so it is recorded <<
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 <<
19 config CC_IS_GCC <<
20 def_bool $(success,test "$(cc-name)" = <<
21 <<
22 config GCC_VERSION <<
23 int <<
24 default $(cc-version) if CC_IS_GCC <<
25 default 0 <<
26 <<
27 config CC_IS_CLANG <<
28 def_bool $(success,test "$(cc-name)" = <<
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 <<
55 config LD_IS_LLD <<
56 def_bool $(success,test "$(ld-name)" = <<
57 <<
58 config LLD_VERSION <<
59 int <<
60 default $(ld-version) if LD_IS_LLD <<
61 default 0 <<
62 <<
63 config RUSTC_VERSION <<
64 int <<
65 default $(rustc-version) <<
66 help <<
67 It does not depend on `RUST` since t <<
68 in a `depends on`. <<
69 <<
70 config RUST_IS_AVAILABLE <<
71 def_bool $(success,$(srctree)/scripts/ <<
72 help <<
73 This shows whether a suitable Rust t <<
74 <<
75 Please see Documentation/rust/quick- <<
76 to satisfy the build requirements of <<
77 <<
78 In particular, the Makefile target ' <<
79 why the Rust toolchain is not being <<
80 <<
81 config RUSTC_LLVM_VERSION <<
82 int <<
83 default $(rustc-llvm-version) <<
84 <<
85 config CC_CAN_LINK <<
86 bool <<
87 default $(success,$(srctree)/scripts/c <<
88 default $(success,$(srctree)/scripts/c <<
89 4
90 config CC_CAN_LINK_STATIC !! 5 config KERNELVERSION
91 bool !! 6 string
92 default $(success,$(srctree)/scripts/c !! 7 option env="KERNELVERSION"
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 8
123 config PAHOLE_VERSION !! 9 config DEFCONFIG_LIST
124 int !! 10 string
125 default $(shell,$(srctree)/scripts/pah !! 11 depends on !UML
>> 12 option defconfig_list
>> 13 default "/lib/modules/$UNAME_RELEASE/.config"
>> 14 default "/etc/kernel-config"
>> 15 default "/boot/config-$UNAME_RELEASE"
>> 16 default "$ARCH_DEFCONFIG"
>> 17 default "arch/$ARCH/defconfig"
126 18
127 config CONSTRUCTORS 19 config CONSTRUCTORS
128 bool 20 bool
>> 21 depends on !UML
129 22
130 config IRQ_WORK 23 config IRQ_WORK
131 def_bool y if SMP !! 24 bool
132 25
133 config BUILDTIME_TABLE_SORT !! 26 config BUILDTIME_EXTABLE_SORT
134 bool 27 bool
135 28
136 config THREAD_INFO_IN_TASK 29 config THREAD_INFO_IN_TASK
137 bool 30 bool
138 help 31 help
139 Select this to move thread_info off 32 Select this to move thread_info off the stack into task_struct. To
140 make this work, an arch will need to 33 make this work, an arch will need to remove all thread_info fields
141 except flags and fix any runtime bug 34 except flags and fix any runtime bugs.
142 35
143 One subtle change that will be neede 36 One subtle change that will be needed is to use try_get_task_stack()
144 and put_task_stack() in save_thread_ 37 and put_task_stack() in save_thread_stack_tsk() and get_wchan().
145 38
146 menu "General setup" 39 menu "General setup"
147 40
148 config BROKEN 41 config BROKEN
149 bool 42 bool
150 43
151 config BROKEN_ON_SMP 44 config BROKEN_ON_SMP
152 bool 45 bool
153 depends on BROKEN || !SMP 46 depends on BROKEN || !SMP
154 default y 47 default y
155 48
156 config INIT_ENV_ARG_LIMIT 49 config INIT_ENV_ARG_LIMIT
157 int 50 int
158 default 32 if !UML 51 default 32 if !UML
159 default 128 if UML 52 default 128 if UML
160 help 53 help
161 Maximum of each of the number of arg 54 Maximum of each of the number of arguments and environment
162 variables passed to init from the ke 55 variables passed to init from the kernel command line.
163 56
>> 57
>> 58 config CROSS_COMPILE
>> 59 string "Cross-compiler tool prefix"
>> 60 help
>> 61 Same as running 'make CROSS_COMPILE=prefix-' but stored for
>> 62 default make runs in this kernel build directory. You don't
>> 63 need to set this unless you want the configured kernel build
>> 64 directory to select the cross-compiler automatically.
>> 65
164 config COMPILE_TEST 66 config COMPILE_TEST
165 bool "Compile also drivers which will 67 bool "Compile also drivers which will not load"
166 depends on HAS_IOMEM 68 depends on HAS_IOMEM
167 help 69 help
168 Some drivers can be compiled on a di 70 Some drivers can be compiled on a different platform than they are
169 intended to be run on. Despite they 71 intended to be run on. Despite they cannot be loaded there (or even
170 when they load they cannot be used d 72 when they load they cannot be used due to missing HW support),
171 developers still, opposing to distri 73 developers still, opposing to distributors, might want to build such
172 drivers to compile-test them. 74 drivers to compile-test them.
173 75
174 If you are a developer and want to b 76 If you are a developer and want to build everything available, say Y
175 here. If you are a user/distributor, 77 here. If you are a user/distributor, say N here to exclude useless
176 drivers to be distributed. 78 drivers to be distributed.
177 79
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 80 config LOCALVERSION
206 string "Local version - append to kern 81 string "Local version - append to kernel release"
207 help 82 help
208 Append an extra string to the end of 83 Append an extra string to the end of your kernel version.
209 This will show up when you type unam 84 This will show up when you type uname, for example.
210 The string you set here will be appe 85 The string you set here will be appended after the contents of
211 any files with a filename matching l 86 any files with a filename matching localversion* in your
212 object and source tree, in that orde 87 object and source tree, in that order. Your total string can
213 be a maximum of 64 characters. 88 be a maximum of 64 characters.
214 89
215 config LOCALVERSION_AUTO 90 config LOCALVERSION_AUTO
216 bool "Automatically append version inf 91 bool "Automatically append version information to the version string"
217 default y 92 default y
218 depends on !COMPILE_TEST 93 depends on !COMPILE_TEST
219 help 94 help
220 This will try to automatically deter 95 This will try to automatically determine if the current tree is a
221 release tree by looking for git tags 96 release tree by looking for git tags that belong to the current
222 top of tree revision. 97 top of tree revision.
223 98
224 A string of the format -gxxxxxxxx wi 99 A string of the format -gxxxxxxxx will be added to the localversion
225 if a git-based tree is found. The s 100 if a git-based tree is found. The string generated by this will be
226 appended after any matching localver 101 appended after any matching localversion* files, and after the value
227 set in CONFIG_LOCALVERSION. 102 set in CONFIG_LOCALVERSION.
228 103
229 (The actual string used here is the !! 104 (The actual string used here is the first eight characters produced
230 by running the command: 105 by running the command:
231 106
232 $ git rev-parse --verify HEAD 107 $ git rev-parse --verify HEAD
233 108
234 which is done within the script "scr 109 which is done within the script "scripts/setlocalversion".)
235 110
236 config BUILD_SALT <<
237 string "Build ID Salt" <<
238 default "" <<
239 help <<
240 The build ID is used to link binarie <<
241 this option will use the value in th <<
242 This is mostly useful for distributi <<
243 build is unique between builds. It's <<
244 <<
245 config HAVE_KERNEL_GZIP 111 config HAVE_KERNEL_GZIP
246 bool 112 bool
247 113
248 config HAVE_KERNEL_BZIP2 114 config HAVE_KERNEL_BZIP2
249 bool 115 bool
250 116
251 config HAVE_KERNEL_LZMA 117 config HAVE_KERNEL_LZMA
252 bool 118 bool
253 119
254 config HAVE_KERNEL_XZ 120 config HAVE_KERNEL_XZ
255 bool 121 bool
256 122
257 config HAVE_KERNEL_LZO 123 config HAVE_KERNEL_LZO
258 bool 124 bool
259 125
260 config HAVE_KERNEL_LZ4 126 config HAVE_KERNEL_LZ4
261 bool 127 bool
262 128
263 config HAVE_KERNEL_ZSTD <<
264 bool <<
265 <<
266 config HAVE_KERNEL_UNCOMPRESSED <<
267 bool <<
268 <<
269 choice 129 choice
270 prompt "Kernel compression mode" 130 prompt "Kernel compression mode"
271 default KERNEL_GZIP 131 default KERNEL_GZIP
272 depends on HAVE_KERNEL_GZIP || HAVE_KE !! 132 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4
273 help 133 help
274 The linux kernel is a kind of self-e 134 The linux kernel is a kind of self-extracting executable.
275 Several compression algorithms are a 135 Several compression algorithms are available, which differ
276 in efficiency, compression and decom 136 in efficiency, compression and decompression speed.
277 Compression speed is only relevant w 137 Compression speed is only relevant when building a kernel.
278 Decompression speed is relevant at e 138 Decompression speed is relevant at each boot.
279 139
280 If you have any problems with bzip2 140 If you have any problems with bzip2 or lzma compressed
281 kernels, mail me (Alain Knaff) <alain 141 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
282 version of this functionality (bzip2 142 version of this functionality (bzip2 only), for 2.4, was
283 supplied by Christian Ludwig) 143 supplied by Christian Ludwig)
284 144
285 High compression options are mostly 145 High compression options are mostly useful for users, who
286 are low on disk space (embedded syst 146 are low on disk space (embedded systems), but for whom ram
287 size matters less. 147 size matters less.
288 148
289 If in doubt, select 'gzip' 149 If in doubt, select 'gzip'
290 150
291 config KERNEL_GZIP 151 config KERNEL_GZIP
292 bool "Gzip" 152 bool "Gzip"
293 depends on HAVE_KERNEL_GZIP 153 depends on HAVE_KERNEL_GZIP
294 help 154 help
295 The old and tried gzip compression. 155 The old and tried gzip compression. It provides a good balance
296 between compression ratio and decomp 156 between compression ratio and decompression speed.
297 157
298 config KERNEL_BZIP2 158 config KERNEL_BZIP2
299 bool "Bzip2" 159 bool "Bzip2"
300 depends on HAVE_KERNEL_BZIP2 160 depends on HAVE_KERNEL_BZIP2
301 help 161 help
302 Its compression ratio and speed is i 162 Its compression ratio and speed is intermediate.
303 Decompression speed is slowest among 163 Decompression speed is slowest among the choices. The kernel
304 size is about 10% smaller with bzip2 164 size is about 10% smaller with bzip2, in comparison to gzip.
305 Bzip2 uses a large amount of memory. 165 Bzip2 uses a large amount of memory. For modern kernels you
306 will need at least 8MB RAM or more f 166 will need at least 8MB RAM or more for booting.
307 167
308 config KERNEL_LZMA 168 config KERNEL_LZMA
309 bool "LZMA" 169 bool "LZMA"
310 depends on HAVE_KERNEL_LZMA 170 depends on HAVE_KERNEL_LZMA
311 help 171 help
312 This compression algorithm's ratio i 172 This compression algorithm's ratio is best. Decompression speed
313 is between gzip and bzip2. Compress 173 is between gzip and bzip2. Compression is slowest.
314 The kernel size is about 33% smaller 174 The kernel size is about 33% smaller with LZMA in comparison to gzip.
315 175
316 config KERNEL_XZ 176 config KERNEL_XZ
317 bool "XZ" 177 bool "XZ"
318 depends on HAVE_KERNEL_XZ 178 depends on HAVE_KERNEL_XZ
319 help 179 help
320 XZ uses the LZMA2 algorithm and inst 180 XZ uses the LZMA2 algorithm and instruction set specific
321 BCJ filters which can improve compre 181 BCJ filters which can improve compression ratio of executable
322 code. The size of the kernel is abou 182 code. The size of the kernel is about 30% smaller with XZ in
323 comparison to gzip. On architectures 183 comparison to gzip. On architectures for which there is a BCJ
324 filter (i386, x86_64, ARM, ARM64, RI !! 184 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
325 and SPARC), XZ will create a few per !! 185 will create a few percent smaller kernel than plain LZMA.
326 plain LZMA. <<
327 186
328 The speed is about the same as with 187 The speed is about the same as with LZMA: The decompression
329 speed of XZ is better than that of b 188 speed of XZ is better than that of bzip2 but worse than gzip
330 and LZO. Compression is slow. 189 and LZO. Compression is slow.
331 190
332 config KERNEL_LZO 191 config KERNEL_LZO
333 bool "LZO" 192 bool "LZO"
334 depends on HAVE_KERNEL_LZO 193 depends on HAVE_KERNEL_LZO
335 help 194 help
336 Its compression ratio is the poorest 195 Its compression ratio is the poorest among the choices. The kernel
337 size is about 10% bigger than gzip; 196 size is about 10% bigger than gzip; however its speed
338 (both compression and decompression) 197 (both compression and decompression) is the fastest.
339 198
340 config KERNEL_LZ4 199 config KERNEL_LZ4
341 bool "LZ4" 200 bool "LZ4"
342 depends on HAVE_KERNEL_LZ4 201 depends on HAVE_KERNEL_LZ4
343 help 202 help
344 LZ4 is an LZ77-type compressor with 203 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
345 A preliminary version of LZ4 de/comp 204 A preliminary version of LZ4 de/compression tool is available at
346 <https://code.google.com/p/lz4/>. 205 <https://code.google.com/p/lz4/>.
347 206
348 Its compression ratio is worse than 207 Its compression ratio is worse than LZO. The size of the kernel
349 is about 8% bigger than LZO. But the 208 is about 8% bigger than LZO. But the decompression speed is
350 faster than LZO. 209 faster than LZO.
351 210
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 <<
363 bool "None" <<
364 depends on HAVE_KERNEL_UNCOMPRESSED <<
365 help <<
366 Produce uncompressed kernel image. T <<
367 you want. It is useful for debugging <<
368 environments, where decompressing an <<
369 slow. This option allows early boot <<
370 and jump right at uncompressed kerne <<
371 <<
372 endchoice 211 endchoice
373 212
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 213 config DEFAULT_HOSTNAME
385 string "Default hostname" 214 string "Default hostname"
386 default "(none)" 215 default "(none)"
387 help 216 help
388 This option determines the default s 217 This option determines the default system hostname before userspace
389 calls sethostname(2). The kernel tra 218 calls sethostname(2). The kernel traditionally uses "(none)" here,
390 but you may wish to use a different 219 but you may wish to use a different default here to make a minimal
391 system more usable with less configu 220 system more usable with less configuration.
392 221
>> 222 config SWAP
>> 223 bool "Support for paging of anonymous memory (swap)"
>> 224 depends on MMU && BLOCK
>> 225 default y
>> 226 help
>> 227 This option allows you to choose whether you want to have support
>> 228 for so called swap devices or swap files in your kernel that are
>> 229 used to provide more virtual memory than the actual RAM present
>> 230 in your computer. If unsure say Y.
>> 231
393 config SYSVIPC 232 config SYSVIPC
394 bool "System V IPC" 233 bool "System V IPC"
395 help !! 234 ---help---
396 Inter Process Communication is a sui 235 Inter Process Communication is a suite of library functions and
397 system calls which let processes (ru 236 system calls which let processes (running programs) synchronize and
398 exchange information. It is generall 237 exchange information. It is generally considered to be a good thing,
399 and some programs won't run unless y 238 and some programs won't run unless you say Y here. In particular, if
400 you want to run the DOS emulator dos 239 you want to run the DOS emulator dosemu under Linux (read the
401 DOSEMU-HOWTO, available from <http:/ 240 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
402 you'll need to say Y here. 241 you'll need to say Y here.
403 242
404 You can find documentation about IPC 243 You can find documentation about IPC with "info ipc" and also in
405 section 6.4 of the Linux Programmer' 244 section 6.4 of the Linux Programmer's Guide, available from
406 <http://www.tldp.org/guides.html>. 245 <http://www.tldp.org/guides.html>.
407 246
408 config SYSVIPC_SYSCTL 247 config SYSVIPC_SYSCTL
409 bool 248 bool
410 depends on SYSVIPC 249 depends on SYSVIPC
411 depends on SYSCTL 250 depends on SYSCTL
412 default y 251 default y
413 252
414 config SYSVIPC_COMPAT <<
415 def_bool y <<
416 depends on COMPAT && SYSVIPC <<
417 <<
418 config POSIX_MQUEUE 253 config POSIX_MQUEUE
419 bool "POSIX Message Queues" 254 bool "POSIX Message Queues"
420 depends on NET 255 depends on NET
421 help !! 256 ---help---
422 POSIX variant of message queues is a 257 POSIX variant of message queues is a part of IPC. In POSIX message
423 queues every message has a priority 258 queues every message has a priority which decides about succession
424 of receiving it by a process. If you 259 of receiving it by a process. If you want to compile and run
425 programs written e.g. for Solaris wi 260 programs written e.g. for Solaris with use of its POSIX message
426 queues (functions mq_*) say Y here. 261 queues (functions mq_*) say Y here.
427 262
428 POSIX message queues are visible as 263 POSIX message queues are visible as a filesystem called 'mqueue'
429 and can be mounted somewhere if you 264 and can be mounted somewhere if you want to do filesystem
430 operations on message queues. 265 operations on message queues.
431 266
432 If unsure, say Y. 267 If unsure, say Y.
433 268
434 config POSIX_MQUEUE_SYSCTL 269 config POSIX_MQUEUE_SYSCTL
435 bool 270 bool
436 depends on POSIX_MQUEUE 271 depends on POSIX_MQUEUE
437 depends on SYSCTL 272 depends on SYSCTL
438 default y 273 default y
439 274
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 275 config CROSS_MEMORY_ATTACH
453 bool "Enable process_vm_readv/writev s 276 bool "Enable process_vm_readv/writev syscalls"
454 depends on MMU 277 depends on MMU
455 default y 278 default y
456 help 279 help
457 Enabling this option adds the system 280 Enabling this option adds the system calls process_vm_readv and
458 process_vm_writev which allow a proc 281 process_vm_writev which allow a process with the correct privileges
459 to directly read from or write to an 282 to directly read from or write to another process' address space.
460 See the man page for more details. 283 See the man page for more details.
461 284
>> 285 config FHANDLE
>> 286 bool "open by fhandle syscalls" if EXPERT
>> 287 select EXPORTFS
>> 288 default y
>> 289 help
>> 290 If you say Y here, a user level program will be able to map
>> 291 file names to handle and then later use the handle for
>> 292 different file system operations. This is useful in implementing
>> 293 userspace file servers, which now track files using handles instead
>> 294 of names. The handle would remain the same even if file names
>> 295 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
>> 296 syscalls.
>> 297
462 config USELIB 298 config USELIB
463 bool "uselib syscall (for libc5 and ea !! 299 bool "uselib syscall"
464 default ALPHA || M68K || SPARC !! 300 def_bool ALPHA || M68K || SPARC || X86_32 || IA32_EMULATION
465 help 301 help
466 This option enables the uselib sysca 302 This option enables the uselib syscall, a system call used in the
467 dynamic linker from libc5 and earlie 303 dynamic linker from libc5 and earlier. glibc does not use this
468 system call. If you intend to run p 304 system call. If you intend to run programs built on libc5 or
469 earlier, you may need to enable this 305 earlier, you may need to enable this syscall. Current systems
470 running glibc can safely disable thi 306 running glibc can safely disable this.
471 307
472 config AUDIT 308 config AUDIT
473 bool "Auditing support" 309 bool "Auditing support"
474 depends on NET 310 depends on NET
475 help 311 help
476 Enable auditing infrastructure that 312 Enable auditing infrastructure that can be used with another
477 kernel subsystem, such as SELinux (w 313 kernel subsystem, such as SELinux (which requires this for
478 logging of avc messages output). Sy 314 logging of avc messages output). System call auditing is included
479 on architectures which support it. 315 on architectures which support it.
480 316
481 config HAVE_ARCH_AUDITSYSCALL 317 config HAVE_ARCH_AUDITSYSCALL
482 bool 318 bool
483 319
484 config AUDITSYSCALL 320 config AUDITSYSCALL
485 def_bool y 321 def_bool y
486 depends on AUDIT && HAVE_ARCH_AUDITSYS 322 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
>> 323
>> 324 config AUDIT_WATCH
>> 325 def_bool y
>> 326 depends on AUDITSYSCALL
>> 327 select FSNOTIFY
>> 328
>> 329 config AUDIT_TREE
>> 330 def_bool y
>> 331 depends on AUDITSYSCALL
487 select FSNOTIFY 332 select FSNOTIFY
488 333
489 source "kernel/irq/Kconfig" 334 source "kernel/irq/Kconfig"
490 source "kernel/time/Kconfig" 335 source "kernel/time/Kconfig"
491 source "kernel/bpf/Kconfig" <<
492 source "kernel/Kconfig.preempt" <<
493 336
494 menu "CPU/Task time and stats accounting" 337 menu "CPU/Task time and stats accounting"
495 338
496 config VIRT_CPU_ACCOUNTING 339 config VIRT_CPU_ACCOUNTING
497 bool 340 bool
498 341
499 choice 342 choice
500 prompt "Cputime accounting" 343 prompt "Cputime accounting"
501 default TICK_CPU_ACCOUNTING !! 344 default TICK_CPU_ACCOUNTING if !PPC64
>> 345 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
502 346
503 # Kind of a stub config for the pure tick base 347 # Kind of a stub config for the pure tick based cputime accounting
504 config TICK_CPU_ACCOUNTING 348 config TICK_CPU_ACCOUNTING
505 bool "Simple tick based cputime accoun 349 bool "Simple tick based cputime accounting"
506 depends on !S390 && !NO_HZ_FULL 350 depends on !S390 && !NO_HZ_FULL
507 help 351 help
508 This is the basic tick based cputime 352 This is the basic tick based cputime accounting that maintains
509 statistics about user, system and id 353 statistics about user, system and idle time spent on per jiffies
510 granularity. 354 granularity.
511 355
512 If unsure, say Y. 356 If unsure, say Y.
513 357
514 config VIRT_CPU_ACCOUNTING_NATIVE 358 config VIRT_CPU_ACCOUNTING_NATIVE
515 bool "Deterministic task and CPU time 359 bool "Deterministic task and CPU time accounting"
516 depends on HAVE_VIRT_CPU_ACCOUNTING && 360 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
517 select VIRT_CPU_ACCOUNTING 361 select VIRT_CPU_ACCOUNTING
518 help 362 help
519 Select this option to enable more ac 363 Select this option to enable more accurate task and CPU time
520 accounting. This is done by reading 364 accounting. This is done by reading a CPU counter on each
521 kernel entry and exit and on transit 365 kernel entry and exit and on transitions within the kernel
522 between system, softirq and hardirq 366 between system, softirq and hardirq state, so there is a
523 small performance impact. In the ca 367 small performance impact. In the case of s390 or IBM POWER > 5,
524 this also enables accounting of stol 368 this also enables accounting of stolen time on logically-partitioned
525 systems. 369 systems.
526 370
527 config VIRT_CPU_ACCOUNTING_GEN 371 config VIRT_CPU_ACCOUNTING_GEN
528 bool "Full dynticks CPU time accountin 372 bool "Full dynticks CPU time accounting"
529 depends on HAVE_CONTEXT_TRACKING_USER !! 373 depends on HAVE_CONTEXT_TRACKING
530 depends on HAVE_VIRT_CPU_ACCOUNTING_GE 374 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
531 depends on GENERIC_CLOCKEVENTS <<
532 select VIRT_CPU_ACCOUNTING 375 select VIRT_CPU_ACCOUNTING
533 select CONTEXT_TRACKING_USER !! 376 select CONTEXT_TRACKING
534 help 377 help
535 Select this option to enable task an 378 Select this option to enable task and CPU time accounting on full
536 dynticks systems. This accounting is 379 dynticks systems. This accounting is implemented by watching every
537 kernel-user boundaries using the con 380 kernel-user boundaries using the context tracking subsystem.
538 The accounting is thus performed at 381 The accounting is thus performed at the expense of some significant
539 overhead. 382 overhead.
540 383
541 For now this is only useful if you a 384 For now this is only useful if you are working on the full
542 dynticks subsystem development. 385 dynticks subsystem development.
543 386
544 If unsure, say N. 387 If unsure, say N.
545 388
546 endchoice 389 endchoice
547 390
548 config IRQ_TIME_ACCOUNTING 391 config IRQ_TIME_ACCOUNTING
549 bool "Fine granularity task level IRQ 392 bool "Fine granularity task level IRQ time accounting"
550 depends on HAVE_IRQ_TIME_ACCOUNTING && 393 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
551 help 394 help
552 Select this option to enable fine gr 395 Select this option to enable fine granularity task irq time
553 accounting. This is done by reading 396 accounting. This is done by reading a timestamp on each
554 transitions between softirq and hard 397 transitions between softirq and hardirq state, so there can be a
555 small performance impact. 398 small performance impact.
556 399
557 If in doubt, say N here. 400 If in doubt, say N here.
558 401
559 config HAVE_SCHED_AVG_IRQ <<
560 def_bool y <<
561 depends on IRQ_TIME_ACCOUNTING || PARA <<
562 depends on SMP <<
563 <<
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 402 config BSD_PROCESS_ACCT
584 bool "BSD Process Accounting" 403 bool "BSD Process Accounting"
585 depends on MULTIUSER 404 depends on MULTIUSER
586 help 405 help
587 If you say Y here, a user level prog 406 If you say Y here, a user level program will be able to instruct the
588 kernel (via a special system call) t 407 kernel (via a special system call) to write process accounting
589 information to a file: whenever a pr 408 information to a file: whenever a process exits, information about
590 that process will be appended to the 409 that process will be appended to the file by the kernel. The
591 information includes things such as 410 information includes things such as creation time, owning user,
592 command name, memory usage, controll 411 command name, memory usage, controlling terminal etc. (the complete
593 list is in the struct acct in <file: 412 list is in the struct acct in <file:include/linux/acct.h>). It is
594 up to the user level program to do u 413 up to the user level program to do useful things with this
595 information. This is generally a go 414 information. This is generally a good idea, so say Y.
596 415
597 config BSD_PROCESS_ACCT_V3 416 config BSD_PROCESS_ACCT_V3
598 bool "BSD Process Accounting version 3 417 bool "BSD Process Accounting version 3 file format"
599 depends on BSD_PROCESS_ACCT 418 depends on BSD_PROCESS_ACCT
600 default n 419 default n
601 help 420 help
602 If you say Y here, the process accou 421 If you say Y here, the process accounting information is written
603 in a new file format that also logs 422 in a new file format that also logs the process IDs of each
604 process and its parent. Note that th !! 423 process and it's parent. Note that this file format is incompatible
605 with previous v0/v1/v2 file formats, 424 with previous v0/v1/v2 file formats, so you will need updated tools
606 for processing it. A preliminary ver 425 for processing it. A preliminary version of these tools is available
607 at <http://www.gnu.org/software/acct 426 at <http://www.gnu.org/software/acct/>.
608 427
609 config TASKSTATS 428 config TASKSTATS
610 bool "Export task/process statistics t 429 bool "Export task/process statistics through netlink"
611 depends on NET 430 depends on NET
612 depends on MULTIUSER 431 depends on MULTIUSER
613 default n 432 default n
614 help 433 help
615 Export selected statistics for tasks 434 Export selected statistics for tasks/processes through the
616 generic netlink interface. Unlike BS 435 generic netlink interface. Unlike BSD process accounting, the
617 statistics are available during the 436 statistics are available during the lifetime of tasks/processes as
618 responses to commands. Like BSD acco 437 responses to commands. Like BSD accounting, they are sent to user
619 space on task exit. 438 space on task exit.
620 439
621 Say N if unsure. 440 Say N if unsure.
622 441
623 config TASK_DELAY_ACCT 442 config TASK_DELAY_ACCT
624 bool "Enable per-task delay accounting 443 bool "Enable per-task delay accounting"
625 depends on TASKSTATS 444 depends on TASKSTATS
626 select SCHED_INFO 445 select SCHED_INFO
627 help 446 help
628 Collect information on time spent by 447 Collect information on time spent by a task waiting for system
629 resources like cpu, synchronous bloc 448 resources like cpu, synchronous block I/O completion and swapping
630 in pages. Such statistics can help i 449 in pages. Such statistics can help in setting a task's priorities
631 relative to other tasks for cpu, io, 450 relative to other tasks for cpu, io, rss limits etc.
632 451
633 Say N if unsure. 452 Say N if unsure.
634 453
635 config TASK_XACCT 454 config TASK_XACCT
636 bool "Enable extended accounting over 455 bool "Enable extended accounting over taskstats"
637 depends on TASKSTATS 456 depends on TASKSTATS
638 help 457 help
639 Collect extended task accounting dat 458 Collect extended task accounting data and send the data
640 to userland for processing over the 459 to userland for processing over the taskstats interface.
641 460
642 Say N if unsure. 461 Say N if unsure.
643 462
644 config TASK_IO_ACCOUNTING 463 config TASK_IO_ACCOUNTING
645 bool "Enable per-task storage I/O acco 464 bool "Enable per-task storage I/O accounting"
646 depends on TASK_XACCT 465 depends on TASK_XACCT
647 help 466 help
648 Collect information on the number of 467 Collect information on the number of bytes of storage I/O which this
649 task has caused. 468 task has caused.
650 469
651 Say N if unsure. 470 Say N if unsure.
652 471
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" 472 endmenu # "CPU/Task time and stats accounting"
694 473
695 config CPU_ISOLATION <<
696 bool "CPU isolation" <<
697 depends on SMP || COMPILE_TEST <<
698 default y <<
699 help <<
700 Make sure that CPUs running critical <<
701 any source of "noise" such as unboun <<
702 Unbound jobs get offloaded to housek <<
703 the "isolcpus=" boot parameter. <<
704 <<
705 Say Y if unsure. <<
706 <<
707 source "kernel/rcu/Kconfig" 474 source "kernel/rcu/Kconfig"
708 475
>> 476 config BUILD_BIN2C
>> 477 bool
>> 478 default n
>> 479
709 config IKCONFIG 480 config IKCONFIG
710 tristate "Kernel .config support" 481 tristate "Kernel .config support"
711 help !! 482 select BUILD_BIN2C
>> 483 ---help---
712 This option enables the complete Lin 484 This option enables the complete Linux kernel ".config" file
713 contents to be saved in the kernel. 485 contents to be saved in the kernel. It provides documentation
714 of which kernel options are used in 486 of which kernel options are used in a running kernel or in an
715 on-disk kernel. This information ca 487 on-disk kernel. This information can be extracted from the kernel
716 image file with the script scripts/e 488 image file with the script scripts/extract-ikconfig and used as
717 input to rebuild the current kernel 489 input to rebuild the current kernel or to build another kernel.
718 It can also be extracted from a runn 490 It can also be extracted from a running kernel by reading
719 /proc/config.gz if enabled (below). 491 /proc/config.gz if enabled (below).
720 492
721 config IKCONFIG_PROC 493 config IKCONFIG_PROC
722 bool "Enable access to .config through 494 bool "Enable access to .config through /proc/config.gz"
723 depends on IKCONFIG && PROC_FS 495 depends on IKCONFIG && PROC_FS
724 help !! 496 ---help---
725 This option enables access to the ke 497 This option enables access to the kernel configuration file
726 through /proc/config.gz. 498 through /proc/config.gz.
727 499
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 500 config LOG_BUF_SHIFT
738 int "Kernel log buffer size (16 => 64K 501 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
739 range 12 25 !! 502 range 12 25 if !H8300
>> 503 range 12 19 if H8300
740 default 17 504 default 17
741 depends on PRINTK 505 depends on PRINTK
742 help 506 help
743 Select the minimal kernel log buffer 507 Select the minimal kernel log buffer size as a power of 2.
744 The final size is affected by LOG_CP 508 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
745 parameter, see below. Any higher siz 509 parameter, see below. Any higher size also might be forced
746 by "log_buf_len" boot parameter. 510 by "log_buf_len" boot parameter.
747 511
748 Examples: 512 Examples:
749 17 => 128 KB 513 17 => 128 KB
750 16 => 64 KB 514 16 => 64 KB
751 15 => 32 KB 515 15 => 32 KB
752 14 => 16 KB 516 14 => 16 KB
753 13 => 8 KB 517 13 => 8 KB
754 12 => 4 KB 518 12 => 4 KB
755 519
756 config LOG_CPU_MAX_BUF_SHIFT 520 config LOG_CPU_MAX_BUF_SHIFT
757 int "CPU kernel log buffer size contri 521 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
758 depends on SMP 522 depends on SMP
759 range 0 21 523 range 0 21
>> 524 default 12 if !BASE_SMALL
760 default 0 if BASE_SMALL 525 default 0 if BASE_SMALL
761 default 12 <<
762 depends on PRINTK 526 depends on PRINTK
763 help 527 help
764 This option allows to increase the d 528 This option allows to increase the default ring buffer size
765 according to the number of CPUs. The 529 according to the number of CPUs. The value defines the contribution
766 of each CPU as a power of 2. The use 530 of each CPU as a power of 2. The used space is typically only few
767 lines however it might be much more 531 lines however it might be much more when problems are reported,
768 e.g. backtraces. 532 e.g. backtraces.
769 533
770 The increased size means that a new 534 The increased size means that a new buffer has to be allocated and
771 the original static one is unused. I 535 the original static one is unused. It makes sense only on systems
772 with more CPUs. Therefore this value 536 with more CPUs. Therefore this value is used only when the sum of
773 contributions is greater than the ha 537 contributions is greater than the half of the default kernel ring
774 buffer as defined by LOG_BUF_SHIFT. 538 buffer as defined by LOG_BUF_SHIFT. The default values are set
775 so that more than 16 CPUs are needed !! 539 so that more than 64 CPUs are needed to trigger the allocation.
776 540
777 Also this option is ignored when "lo 541 Also this option is ignored when "log_buf_len" kernel parameter is
778 used as it forces an exact (power of 542 used as it forces an exact (power of two) size of the ring buffer.
779 543
780 The number of possible CPUs is used 544 The number of possible CPUs is used for this computation ignoring
781 hotplugging making the computation o 545 hotplugging making the computation optimal for the worst case
782 scenario while allowing a simple alg 546 scenario while allowing a simple algorithm to be used from bootup.
783 547
784 Examples shift values and their mean 548 Examples shift values and their meaning:
785 17 => 128 KB for each CPU 549 17 => 128 KB for each CPU
786 16 => 64 KB for each CPU 550 16 => 64 KB for each CPU
787 15 => 32 KB for each CPU 551 15 => 32 KB for each CPU
788 14 => 16 KB for each CPU 552 14 => 16 KB for each CPU
789 13 => 8 KB for each CPU 553 13 => 8 KB for each CPU
790 12 => 4 KB for each CPU 554 12 => 4 KB for each CPU
791 555
792 config PRINTK_INDEX !! 556 config PRINTK_SAFE_LOG_BUF_SHIFT
793 bool "Printk indexing debugfs interfac !! 557 int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)"
794 depends on PRINTK && DEBUG_FS !! 558 range 10 21
795 help !! 559 default 13
796 Add support for indexing of all prin !! 560 depends on PRINTK
797 at <debugfs>/printk/index/<module>. !! 561 help
798 !! 562 Select the size of an alternate printk per-CPU buffer where messages
799 This can be used as part of maintain !! 563 printed from usafe contexts are temporary stored. One example would
800 /dev/kmsg, as it permits auditing th !! 564 be NMI messages, another one - printk recursion. The messages are
801 kernel, allowing detection of cases !! 565 copied to the main log buffer in a safe context to avoid a deadlock.
802 changed or no longer present. !! 566 The value defines the size as a power of 2.
>> 567
>> 568 Those messages are rare and limited. The largest one is when
>> 569 a backtrace is printed. It usually fits into 4KB. Select
>> 570 8KB if you want to be on the safe side.
803 571
804 There is no additional runtime cost !! 572 Examples:
>> 573 17 => 128 KB for each CPU
>> 574 16 => 64 KB for each CPU
>> 575 15 => 32 KB for each CPU
>> 576 14 => 16 KB for each CPU
>> 577 13 => 8 KB for each CPU
>> 578 12 => 4 KB for each CPU
805 579
806 # 580 #
807 # Architectures with an unreliable sched_clock 581 # Architectures with an unreliable sched_clock() should select this:
808 # 582 #
809 config HAVE_UNSTABLE_SCHED_CLOCK 583 config HAVE_UNSTABLE_SCHED_CLOCK
810 bool 584 bool
811 585
812 config GENERIC_SCHED_CLOCK 586 config GENERIC_SCHED_CLOCK
813 bool 587 bool
814 588
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 # 589 #
869 # For architectures that want to enable the su 590 # For architectures that want to enable the support for NUMA-affine scheduler
870 # balancing logic: 591 # balancing logic:
871 # 592 #
872 config ARCH_SUPPORTS_NUMA_BALANCING 593 config ARCH_SUPPORTS_NUMA_BALANCING
873 bool 594 bool
874 595
875 # 596 #
876 # For architectures that prefer to flush all T 597 # For architectures that prefer to flush all TLBs after a number of pages
877 # are unmapped instead of sending one IPI per 598 # are unmapped instead of sending one IPI per page to flush. The architecture
878 # must provide guarantees on what happens if a 599 # must provide guarantees on what happens if a clean TLB cache entry is
879 # written after the unmap. Details are in mm/r 600 # written after the unmap. Details are in mm/rmap.c near the check for
880 # should_defer_flush. The architecture should 601 # should_defer_flush. The architecture should also consider if the full flush
881 # and the refill costs are offset by the savin 602 # and the refill costs are offset by the savings of sending fewer IPIs.
882 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 603 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
883 bool 604 bool
884 605
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 # 606 #
915 # For architectures that know their GCC __int1 607 # For architectures that know their GCC __int128 support is sound
916 # 608 #
917 config ARCH_SUPPORTS_INT128 609 config ARCH_SUPPORTS_INT128
918 bool 610 bool
919 611
920 # For architectures that (ab)use NUMA to repre 612 # For architectures that (ab)use NUMA to represent different memory regions
921 # all cpu-local but of different latencies, su 613 # all cpu-local but of different latencies, such as SuperH.
922 # 614 #
923 config ARCH_WANT_NUMA_VARIABLE_LOCALITY 615 config ARCH_WANT_NUMA_VARIABLE_LOCALITY
924 bool 616 bool
925 617
926 config NUMA_BALANCING 618 config NUMA_BALANCING
927 bool "Memory placement aware NUMA sche 619 bool "Memory placement aware NUMA scheduler"
928 depends on ARCH_SUPPORTS_NUMA_BALANCIN 620 depends on ARCH_SUPPORTS_NUMA_BALANCING
929 depends on !ARCH_WANT_NUMA_VARIABLE_LO 621 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
930 depends on SMP && NUMA && MIGRATION && !! 622 depends on SMP && NUMA && MIGRATION
931 help 623 help
932 This option adds support for automat 624 This option adds support for automatic NUMA aware memory/task placement.
933 The mechanism is quite primitive and 625 The mechanism is quite primitive and is based on migrating memory when
934 it has references to the node the ta 626 it has references to the node the task is running on.
935 627
936 This system will be inactive on UMA 628 This system will be inactive on UMA systems.
937 629
938 config NUMA_BALANCING_DEFAULT_ENABLED 630 config NUMA_BALANCING_DEFAULT_ENABLED
939 bool "Automatically enable NUMA aware 631 bool "Automatically enable NUMA aware memory/task placement"
940 default y 632 default y
941 depends on NUMA_BALANCING 633 depends on NUMA_BALANCING
942 help 634 help
943 If set, automatic NUMA balancing wil 635 If set, automatic NUMA balancing will be enabled if running on a NUMA
944 machine. 636 machine.
945 637
946 config SLAB_OBJ_EXT <<
947 bool <<
948 <<
949 menuconfig CGROUPS 638 menuconfig CGROUPS
950 bool "Control Group support" 639 bool "Control Group support"
951 select KERNFS 640 select KERNFS
952 help 641 help
953 This option adds support for groupin 642 This option adds support for grouping sets of processes together, for
954 use with process control subsystems 643 use with process control subsystems such as Cpusets, CFS, memory
955 controls or device isolation. 644 controls or device isolation.
956 See 645 See
957 - Documentation/scheduler/sche !! 646 - Documentation/scheduler/sched-design-CFS.txt (CFS)
958 - Documentation/admin-guide/cg !! 647 - Documentation/cgroup-v1/ (features for grouping, isolation
959 and 648 and resource control)
960 649
961 Say N if unsure. 650 Say N if unsure.
962 651
963 if CGROUPS 652 if CGROUPS
964 653
965 config PAGE_COUNTER 654 config PAGE_COUNTER
966 bool !! 655 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. <<
977 656
978 config MEMCG 657 config MEMCG
979 bool "Memory controller" 658 bool "Memory controller"
980 select PAGE_COUNTER 659 select PAGE_COUNTER
981 select EVENTFD 660 select EVENTFD
982 select SLAB_OBJ_EXT <<
983 help 661 help
984 Provides control over the memory foo 662 Provides control over the memory footprint of tasks in a cgroup.
985 663
986 config MEMCG_V1 !! 664 config MEMCG_SWAP
987 bool "Legacy cgroup v1 memory controll !! 665 bool "Swap controller"
988 depends on MEMCG !! 666 depends on MEMCG && SWAP
989 default n !! 667 help
990 help !! 668 Provides control over the swap space consumed by tasks in a cgroup.
991 Legacy cgroup v1 memory controller w !! 669
992 cgroup v2 implementation. The v1 is !! 670 config MEMCG_SWAP_ENABLED
993 which haven't migrated to the new cg !! 671 bool "Swap controller enabled by default"
994 do not have any such application the !! 672 depends on MEMCG_SWAP
995 this option disabled. !! 673 default y
996 !! 674 help
997 Please note that feature set of the !! 675 Memory Resource Controller Swap Extension comes with its price in
998 going to shrink due to deprecation p !! 676 a bigger memory consumption. General purpose distribution kernels
999 controller are highly discouraged. !! 677 which want to enable the feature but keep it disabled by default
1000 !! 678 and let the user enable it by swapaccount=1 boot command line
1001 Say N if unsure. !! 679 parameter should have this option unselected.
>> 680 For those who want to have the feature enabled by default should
>> 681 select this option (if, for some reason, they need to disable it
>> 682 then swapaccount=0 does the trick).
1002 683
1003 config BLK_CGROUP 684 config BLK_CGROUP
1004 bool "IO controller" 685 bool "IO controller"
1005 depends on BLOCK 686 depends on BLOCK
1006 default n 687 default n
1007 help !! 688 ---help---
1008 Generic block IO controller cgroup in 689 Generic block IO controller cgroup interface. This is the common
1009 cgroup interface which should be used 690 cgroup interface which should be used by various IO controlling
1010 policies. 691 policies.
1011 692
1012 Currently, CFQ IO scheduler uses it t 693 Currently, CFQ IO scheduler uses it to recognize task groups and
1013 control disk bandwidth allocation (pr 694 control disk bandwidth allocation (proportional time slice allocation)
1014 to such task groups. It is also used 695 to such task groups. It is also used by bio throttling logic in
1015 block layer to implement upper limit 696 block layer to implement upper limit in IO rates on a device.
1016 697
1017 This option only enables generic Bloc 698 This option only enables generic Block IO controller infrastructure.
1018 One needs to also enable actual IO co 699 One needs to also enable actual IO controlling logic/policy. For
1019 enabling proportional weight division 700 enabling proportional weight division of disk bandwidth in CFQ, set
1020 CONFIG_BFQ_GROUP_IOSCHED=y; for enabl !! 701 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1021 CONFIG_BLK_DEV_THROTTLING=y. 702 CONFIG_BLK_DEV_THROTTLING=y.
1022 703
1023 See Documentation/admin-guide/cgroup- !! 704 See Documentation/cgroup-v1/blkio-controller.txt for more information.
>> 705
>> 706 config DEBUG_BLK_CGROUP
>> 707 bool "IO controller debugging"
>> 708 depends on BLK_CGROUP
>> 709 default n
>> 710 ---help---
>> 711 Enable some debugging help. Currently it exports additional stat
>> 712 files in a cgroup which can be useful for debugging.
1024 713
1025 config CGROUP_WRITEBACK 714 config CGROUP_WRITEBACK
1026 bool 715 bool
1027 depends on MEMCG && BLK_CGROUP 716 depends on MEMCG && BLK_CGROUP
1028 default y 717 default y
1029 718
1030 menuconfig CGROUP_SCHED 719 menuconfig CGROUP_SCHED
1031 bool "CPU controller" 720 bool "CPU controller"
1032 default n 721 default n
1033 help 722 help
1034 This feature lets CPU scheduler rec 723 This feature lets CPU scheduler recognize task groups and control CPU
1035 bandwidth allocation to such task g 724 bandwidth allocation to such task groups. It uses cgroups to group
1036 tasks. 725 tasks.
1037 726
1038 if CGROUP_SCHED 727 if CGROUP_SCHED
1039 config GROUP_SCHED_WEIGHT <<
1040 def_bool n <<
1041 <<
1042 config FAIR_GROUP_SCHED 728 config FAIR_GROUP_SCHED
1043 bool "Group scheduling for SCHED_OTHE 729 bool "Group scheduling for SCHED_OTHER"
1044 depends on CGROUP_SCHED 730 depends on CGROUP_SCHED
1045 select GROUP_SCHED_WEIGHT <<
1046 default CGROUP_SCHED 731 default CGROUP_SCHED
1047 732
1048 config CFS_BANDWIDTH 733 config CFS_BANDWIDTH
1049 bool "CPU bandwidth provisioning for 734 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
1050 depends on FAIR_GROUP_SCHED 735 depends on FAIR_GROUP_SCHED
1051 default n 736 default n
1052 help 737 help
1053 This option allows users to define 738 This option allows users to define CPU bandwidth rates (limits) for
1054 tasks running within the fair group 739 tasks running within the fair group scheduler. Groups with no limit
1055 set are considered to be unconstrai 740 set are considered to be unconstrained and will run with no
1056 restriction. 741 restriction.
1057 See Documentation/scheduler/sched-b !! 742 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1058 743
1059 config RT_GROUP_SCHED 744 config RT_GROUP_SCHED
1060 bool "Group scheduling for SCHED_RR/F 745 bool "Group scheduling for SCHED_RR/FIFO"
1061 depends on CGROUP_SCHED 746 depends on CGROUP_SCHED
1062 default n 747 default n
1063 help 748 help
1064 This feature lets you explicitly al 749 This feature lets you explicitly allocate real CPU bandwidth
1065 to task groups. If enabled, it will 750 to task groups. If enabled, it will also make it impossible to
1066 schedule realtime tasks for non-roo 751 schedule realtime tasks for non-root users until you allocate
1067 realtime bandwidth for them. 752 realtime bandwidth for them.
1068 See Documentation/scheduler/sched-r !! 753 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 754
1076 endif #CGROUP_SCHED 755 endif #CGROUP_SCHED
1077 756
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 757 config CGROUP_PIDS
1105 bool "PIDs controller" 758 bool "PIDs controller"
1106 help 759 help
1107 Provides enforcement of process num 760 Provides enforcement of process number limits in the scope of a
1108 cgroup. Any attempt to fork more pr 761 cgroup. Any attempt to fork more processes than is allowed in the
1109 cgroup will fail. PIDs are fundamen 762 cgroup will fail. PIDs are fundamentally a global resource because it
1110 is fairly trivial to reach PID exha 763 is fairly trivial to reach PID exhaustion before you reach even a
1111 conservative kmemcg limit. As a res 764 conservative kmemcg limit. As a result, it is possible to grind a
1112 system to halt without being limite 765 system to halt without being limited by other cgroup policies. The
1113 PIDs controller is designed to stop 766 PIDs controller is designed to stop this from happening.
1114 767
1115 It should be noted that organisatio 768 It should be noted that organisational operations (such as attaching
1116 to a cgroup hierarchy) will *not* b !! 769 to a cgroup hierarchy will *not* be blocked by the PIDs controller),
1117 since the PIDs limit only affects a 770 since the PIDs limit only affects a process's ability to fork, not to
1118 attach to a cgroup. 771 attach to a cgroup.
1119 772
1120 config CGROUP_RDMA 773 config CGROUP_RDMA
1121 bool "RDMA controller" 774 bool "RDMA controller"
1122 help 775 help
1123 Provides enforcement of RDMA resour 776 Provides enforcement of RDMA resources defined by IB stack.
1124 It is fairly easy for consumers to 777 It is fairly easy for consumers to exhaust RDMA resources, which
1125 can result into resource unavailabi 778 can result into resource unavailability to other consumers.
1126 RDMA controller is designed to stop 779 RDMA controller is designed to stop this from happening.
1127 Attaching processes with active RDM 780 Attaching processes with active RDMA resources to the cgroup
1128 hierarchy is allowed even if can cr 781 hierarchy is allowed even if can cross the hierarchy's limit.
1129 782
1130 config CGROUP_FREEZER 783 config CGROUP_FREEZER
1131 bool "Freezer controller" 784 bool "Freezer controller"
1132 help 785 help
1133 Provides a way to freeze and unfree 786 Provides a way to freeze and unfreeze all tasks in a
1134 cgroup. 787 cgroup.
1135 788
1136 This option affects the ORIGINAL cg 789 This option affects the ORIGINAL cgroup interface. The cgroup2 memory
1137 controller includes important in-ke 790 controller includes important in-kernel memory consumers per default.
1138 791
1139 If you're using cgroup2, say N. 792 If you're using cgroup2, say N.
1140 793
1141 config CGROUP_HUGETLB 794 config CGROUP_HUGETLB
1142 bool "HugeTLB controller" 795 bool "HugeTLB controller"
1143 depends on HUGETLB_PAGE 796 depends on HUGETLB_PAGE
1144 select PAGE_COUNTER 797 select PAGE_COUNTER
1145 default n 798 default n
1146 help 799 help
1147 Provides a cgroup controller for Hu 800 Provides a cgroup controller for HugeTLB pages.
1148 When you enable this, you can put a 801 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1149 The limit is enforced during page f 802 The limit is enforced during page fault. Since HugeTLB doesn't
1150 support page reclaim, enforcing the 803 support page reclaim, enforcing the limit at page fault time implies
1151 that, the application will get SIGB 804 that, the application will get SIGBUS signal if it tries to access
1152 HugeTLB pages beyond its limit. Thi 805 HugeTLB pages beyond its limit. This requires the application to know
1153 beforehand how much HugeTLB pages i 806 beforehand how much HugeTLB pages it would require for its use. The
1154 control group is tracked in the thi 807 control group is tracked in the third page lru pointer. This means
1155 that we cannot use the controller w 808 that we cannot use the controller with huge page less than 3 pages.
1156 809
1157 config CPUSETS 810 config CPUSETS
1158 bool "Cpuset controller" 811 bool "Cpuset controller"
1159 depends on SMP 812 depends on SMP
1160 help 813 help
1161 This option will let you create and 814 This option will let you create and manage CPUSETs which
1162 allow dynamically partitioning a sy 815 allow dynamically partitioning a system into sets of CPUs and
1163 Memory Nodes and assigning tasks to 816 Memory Nodes and assigning tasks to run only within those sets.
1164 This is primarily useful on large S 817 This is primarily useful on large SMP or NUMA systems.
1165 818
1166 Say N if unsure. 819 Say N if unsure.
1167 820
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 821 config PROC_PID_CPUSET
1182 bool "Include legacy /proc/<pid>/cpus 822 bool "Include legacy /proc/<pid>/cpuset file"
1183 depends on CPUSETS 823 depends on CPUSETS
1184 default y 824 default y
1185 825
1186 config CGROUP_DEVICE 826 config CGROUP_DEVICE
1187 bool "Device controller" 827 bool "Device controller"
1188 help 828 help
1189 Provides a cgroup controller implem 829 Provides a cgroup controller implementing whitelists for
1190 devices which a process in the cgro 830 devices which a process in the cgroup can mknod or open.
1191 831
1192 config CGROUP_CPUACCT 832 config CGROUP_CPUACCT
1193 bool "Simple CPU accounting controlle 833 bool "Simple CPU accounting controller"
1194 help 834 help
1195 Provides a simple controller for mo 835 Provides a simple controller for monitoring the
1196 total CPU consumed by the tasks in 836 total CPU consumed by the tasks in a cgroup.
1197 837
1198 config CGROUP_PERF 838 config CGROUP_PERF
1199 bool "Perf controller" 839 bool "Perf controller"
1200 depends on PERF_EVENTS 840 depends on PERF_EVENTS
1201 help 841 help
1202 This option extends the perf per-cp 842 This option extends the perf per-cpu mode to restrict monitoring
1203 to threads which belong to the cgro 843 to threads which belong to the cgroup specified and run on the
1204 designated cpu. Or this can be use !! 844 designated cpu.
1205 so that it can monitor performance <<
1206 845
1207 Say N if unsure. 846 Say N if unsure.
1208 847
1209 config CGROUP_BPF 848 config CGROUP_BPF
1210 bool "Support for eBPF programs attac 849 bool "Support for eBPF programs attached to cgroups"
1211 depends on BPF_SYSCALL 850 depends on BPF_SYSCALL
1212 select SOCK_CGROUP_DATA 851 select SOCK_CGROUP_DATA
1213 help 852 help
1214 Allow attaching eBPF programs to a 853 Allow attaching eBPF programs to a cgroup using the bpf(2)
1215 syscall command BPF_PROG_ATTACH. 854 syscall command BPF_PROG_ATTACH.
1216 855
1217 In which context these programs are 856 In which context these programs are accessed depends on the type
1218 of attachment. For instance, progra 857 of attachment. For instance, programs that are attached using
1219 BPF_CGROUP_INET_INGRESS will be exe 858 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
1220 inet sockets. 859 inet sockets.
1221 860
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 861 config CGROUP_DEBUG
1237 bool "Debug controller" 862 bool "Debug controller"
1238 default n 863 default n
1239 depends on DEBUG_KERNEL 864 depends on DEBUG_KERNEL
1240 help 865 help
1241 This option enables a simple contro 866 This option enables a simple controller that exports
1242 debugging information about the cgr 867 debugging information about the cgroups framework. This
1243 controller is for control cgroup de 868 controller is for control cgroup debugging only. Its
1244 interfaces are not stable. 869 interfaces are not stable.
1245 870
1246 Say N. 871 Say N.
1247 872
1248 config SOCK_CGROUP_DATA 873 config SOCK_CGROUP_DATA
1249 bool 874 bool
1250 default n 875 default n
1251 876
1252 endif # CGROUPS 877 endif # CGROUPS
1253 878
>> 879 config CHECKPOINT_RESTORE
>> 880 bool "Checkpoint/restore support" if EXPERT
>> 881 select PROC_CHILDREN
>> 882 default n
>> 883 help
>> 884 Enables additional kernel features in a sake of checkpoint/restore.
>> 885 In particular it adds auxiliary prctl codes to setup process text,
>> 886 data and heap segment sizes, and a few additional /proc filesystem
>> 887 entries.
>> 888
>> 889 If unsure, say N here.
>> 890
1254 menuconfig NAMESPACES 891 menuconfig NAMESPACES
1255 bool "Namespaces support" if EXPERT 892 bool "Namespaces support" if EXPERT
1256 depends on MULTIUSER 893 depends on MULTIUSER
1257 default !EXPERT 894 default !EXPERT
1258 help 895 help
1259 Provides the way to make tasks work 896 Provides the way to make tasks work with different objects using
1260 the same id. For example same IPC i 897 the same id. For example same IPC id may refer to different objects
1261 or same user id or pid may refer to 898 or same user id or pid may refer to different tasks when used in
1262 different namespaces. 899 different namespaces.
1263 900
1264 if NAMESPACES 901 if NAMESPACES
1265 902
1266 config UTS_NS 903 config UTS_NS
1267 bool "UTS namespace" 904 bool "UTS namespace"
1268 default y 905 default y
1269 help 906 help
1270 In this namespace tasks see differe 907 In this namespace tasks see different info provided with the
1271 uname() system call 908 uname() system call
1272 909
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 910 config IPC_NS
1282 bool "IPC namespace" 911 bool "IPC namespace"
1283 depends on (SYSVIPC || POSIX_MQUEUE) 912 depends on (SYSVIPC || POSIX_MQUEUE)
1284 default y 913 default y
1285 help 914 help
1286 In this namespace tasks work with I 915 In this namespace tasks work with IPC ids which correspond to
1287 different IPC objects in different 916 different IPC objects in different namespaces.
1288 917
1289 config USER_NS 918 config USER_NS
1290 bool "User namespace" 919 bool "User namespace"
1291 default n 920 default n
1292 help 921 help
1293 This allows containers, i.e. vserve 922 This allows containers, i.e. vservers, to use user namespaces
1294 to provide different user info for 923 to provide different user info for different servers.
1295 924
1296 When user namespaces are enabled in 925 When user namespaces are enabled in the kernel it is
1297 recommended that the MEMCG option a 926 recommended that the MEMCG option also be enabled and that
1298 user-space use the memory control g 927 user-space use the memory control groups to limit the amount
1299 of memory a memory unprivileged use 928 of memory a memory unprivileged users can use.
1300 929
1301 If unsure, say N. 930 If unsure, say N.
1302 931
1303 config PID_NS 932 config PID_NS
1304 bool "PID Namespaces" 933 bool "PID Namespaces"
1305 default y 934 default y
1306 help 935 help
1307 Support process id namespaces. Thi 936 Support process id namespaces. This allows having multiple
1308 processes with the same pid as long 937 processes with the same pid as long as they are in different
1309 pid namespaces. This is a building 938 pid namespaces. This is a building block of containers.
1310 939
1311 config NET_NS 940 config NET_NS
1312 bool "Network namespace" 941 bool "Network namespace"
1313 depends on NET 942 depends on NET
1314 default y 943 default y
1315 help 944 help
1316 Allow user space to create what app 945 Allow user space to create what appear to be multiple instances
1317 of the network stack. 946 of the network stack.
1318 947
1319 endif # NAMESPACES 948 endif # NAMESPACES
1320 949
1321 config CHECKPOINT_RESTORE <<
1322 bool "Checkpoint/restore support" <<
1323 depends on PROC_FS <<
1324 select PROC_CHILDREN <<
1325 select KCMP <<
1326 default n <<
1327 help <<
1328 Enables additional kernel features <<
1329 In particular it adds auxiliary prc <<
1330 data and heap segment sizes, and a <<
1331 entries. <<
1332 <<
1333 If unsure, say N here. <<
1334 <<
1335 config SCHED_AUTOGROUP 950 config SCHED_AUTOGROUP
1336 bool "Automatic process group schedul 951 bool "Automatic process group scheduling"
1337 select CGROUPS 952 select CGROUPS
1338 select CGROUP_SCHED 953 select CGROUP_SCHED
1339 select FAIR_GROUP_SCHED 954 select FAIR_GROUP_SCHED
1340 help 955 help
1341 This option optimizes the scheduler 956 This option optimizes the scheduler for common desktop workloads by
1342 automatically creating and populati 957 automatically creating and populating task groups. This separation
1343 of workloads isolates aggressive CP 958 of workloads isolates aggressive CPU burners (like build jobs) from
1344 desktop applications. Task group a 959 desktop applications. Task group autogeneration is currently based
1345 upon task session. 960 upon task session.
1346 961
>> 962 config SYSFS_DEPRECATED
>> 963 bool "Enable deprecated sysfs features to support old userspace tools"
>> 964 depends on SYSFS
>> 965 default n
>> 966 help
>> 967 This option adds code that switches the layout of the "block" class
>> 968 devices, to not show up in /sys/class/block/, but only in
>> 969 /sys/block/.
>> 970
>> 971 This switch is only active when the sysfs.deprecated=1 boot option is
>> 972 passed or the SYSFS_DEPRECATED_V2 option is set.
>> 973
>> 974 This option allows new kernels to run on old distributions and tools,
>> 975 which might get confused by /sys/class/block/. Since 2007/2008 all
>> 976 major distributions and tools handle this just fine.
>> 977
>> 978 Recent distributions and userspace tools after 2009/2010 depend on
>> 979 the existence of /sys/class/block/, and will not work with this
>> 980 option enabled.
>> 981
>> 982 Only if you are using a new kernel on an old distribution, you might
>> 983 need to say Y here.
>> 984
>> 985 config SYSFS_DEPRECATED_V2
>> 986 bool "Enable deprecated sysfs features by default"
>> 987 default n
>> 988 depends on SYSFS
>> 989 depends on SYSFS_DEPRECATED
>> 990 help
>> 991 Enable deprecated sysfs by default.
>> 992
>> 993 See the CONFIG_SYSFS_DEPRECATED option for more details about this
>> 994 option.
>> 995
>> 996 Only if you are using a new kernel on an old distribution, you might
>> 997 need to say Y here. Even then, odds are you would not need it
>> 998 enabled, you can always pass the boot option if absolutely necessary.
>> 999
1347 config RELAY 1000 config RELAY
1348 bool "Kernel->user space relay suppor 1001 bool "Kernel->user space relay support (formerly relayfs)"
1349 select IRQ_WORK 1002 select IRQ_WORK
1350 help 1003 help
1351 This option enables support for rel 1004 This option enables support for relay interface support in
1352 certain file systems (such as debug 1005 certain file systems (such as debugfs).
1353 It is designed to provide an effici 1006 It is designed to provide an efficient mechanism for tools and
1354 facilities to relay large amounts o 1007 facilities to relay large amounts of data from kernel space to
1355 user space. 1008 user space.
1356 1009
1357 If unsure, say N. 1010 If unsure, say N.
1358 1011
1359 config BLK_DEV_INITRD 1012 config BLK_DEV_INITRD
1360 bool "Initial RAM filesystem and RAM 1013 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
>> 1014 depends on BROKEN || !FRV
1361 help 1015 help
1362 The initial RAM filesystem is a ram 1016 The initial RAM filesystem is a ramfs which is loaded by the
1363 boot loader (loadlin or lilo) and t 1017 boot loader (loadlin or lilo) and that is mounted as root
1364 before the normal boot procedure. I 1018 before the normal boot procedure. It is typically used to
1365 load modules needed to mount the "r 1019 load modules needed to mount the "real" root file system,
1366 etc. See <file:Documentation/admin- 1020 etc. See <file:Documentation/admin-guide/initrd.rst> for details.
1367 1021
1368 If RAM disk support (BLK_DEV_RAM) i 1022 If RAM disk support (BLK_DEV_RAM) is also included, this
1369 also enables initial RAM disk (init 1023 also enables initial RAM disk (initrd) support and adds
1370 15 Kbytes (more on some other archi 1024 15 Kbytes (more on some other architectures) to the kernel size.
1371 1025
1372 If unsure say Y. 1026 If unsure say Y.
1373 1027
1374 if BLK_DEV_INITRD 1028 if BLK_DEV_INITRD
1375 1029
1376 source "usr/Kconfig" 1030 source "usr/Kconfig"
1377 1031
1378 endif 1032 endif
1379 1033
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 1034 choice
1435 prompt "Compiler optimization level" 1035 prompt "Compiler optimization level"
1436 default CC_OPTIMIZE_FOR_PERFORMANCE 1036 default CC_OPTIMIZE_FOR_PERFORMANCE
1437 1037
1438 config CC_OPTIMIZE_FOR_PERFORMANCE 1038 config CC_OPTIMIZE_FOR_PERFORMANCE
1439 bool "Optimize for performance (-O2)" !! 1039 bool "Optimize for performance"
1440 help 1040 help
1441 This is the default optimization le 1041 This is the default optimization level for the kernel, building
1442 with the "-O2" compiler flag for be 1042 with the "-O2" compiler flag for best performance and most
1443 helpful compile-time warnings. 1043 helpful compile-time warnings.
1444 1044
1445 config CC_OPTIMIZE_FOR_SIZE 1045 config CC_OPTIMIZE_FOR_SIZE
1446 bool "Optimize for size (-Os)" !! 1046 bool "Optimize for size"
1447 help 1047 help
1448 Choosing this option will pass "-Os !! 1048 Enabling this option will pass "-Os" instead of "-O2" to
1449 in a smaller kernel. !! 1049 your compiler resulting in a smaller kernel.
>> 1050
>> 1051 If unsure, say N.
1450 1052
1451 endchoice 1053 endchoice
1452 1054
1453 config HAVE_LD_DEAD_CODE_DATA_ELIMINATION !! 1055 config SYSCTL
1454 bool 1056 bool
1455 help <<
1456 This requires that the arch annotat <<
1457 its external entry points from bein <<
1458 must also merge .text.*, .data.*, a <<
1459 output sections. Care must be taken <<
1460 sections (e.g., '.text.init'). Typi <<
1461 is used to distinguish them from la <<
1462 <<
1463 config LD_DEAD_CODE_DATA_ELIMINATION <<
1464 bool "Dead code and data elimination <<
1465 depends on HAVE_LD_DEAD_CODE_DATA_ELI <<
1466 depends on EXPERT <<
1467 depends on $(cc-option,-ffunction-sec <<
1468 depends on $(ld-option,--gc-sections) <<
1469 help <<
1470 Enable this if you want to do dead <<
1471 the linker by compiling with -ffunc <<
1472 and linking with --gc-sections. <<
1473 <<
1474 This can reduce on disk and in-memo <<
1475 code and static data, particularly <<
1476 on small systems. This has the poss <<
1477 silently broken kernel if the requi <<
1478 present. This option is not well te <<
1479 own risk. <<
1480 1057
1481 config LD_ORPHAN_WARN !! 1058 config ANON_INODES
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 <<
1494 bool 1059 bool
1495 1060
1496 config HAVE_UID16 1061 config HAVE_UID16
1497 bool 1062 bool
1498 1063
1499 config SYSCTL_EXCEPTION_TRACE 1064 config SYSCTL_EXCEPTION_TRACE
1500 bool 1065 bool
1501 help 1066 help
1502 Enable support for /proc/sys/debug/ 1067 Enable support for /proc/sys/debug/exception-trace.
1503 1068
1504 config SYSCTL_ARCH_UNALIGN_NO_WARN 1069 config SYSCTL_ARCH_UNALIGN_NO_WARN
1505 bool 1070 bool
1506 help 1071 help
1507 Enable support for /proc/sys/kernel 1072 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1508 Allows arch to define/use @no_unali 1073 Allows arch to define/use @no_unaligned_warning to possibly warn
1509 about unaligned access emulation go 1074 about unaligned access emulation going on under the hood.
1510 1075
1511 config SYSCTL_ARCH_UNALIGN_ALLOW 1076 config SYSCTL_ARCH_UNALIGN_ALLOW
1512 bool 1077 bool
1513 help 1078 help
1514 Enable support for /proc/sys/kernel 1079 Enable support for /proc/sys/kernel/unaligned-trap
1515 Allows arches to define/use @unalig 1080 Allows arches to define/use @unaligned_enabled to runtime toggle
1516 the unaligned access emulation. 1081 the unaligned access emulation.
1517 see arch/parisc/kernel/unaligned.c 1082 see arch/parisc/kernel/unaligned.c for reference
1518 1083
1519 config HAVE_PCSPKR_PLATFORM 1084 config HAVE_PCSPKR_PLATFORM
1520 bool 1085 bool
1521 1086
>> 1087 # interpreter that classic socket filters depend on
>> 1088 config BPF
>> 1089 bool
>> 1090
1522 menuconfig EXPERT 1091 menuconfig EXPERT
1523 bool "Configure standard kernel featu 1092 bool "Configure standard kernel features (expert users)"
1524 # Unhide debug options, to make the o 1093 # Unhide debug options, to make the on-by-default options visible
1525 select DEBUG_KERNEL 1094 select DEBUG_KERNEL
1526 help 1095 help
1527 This option allows certain base ker 1096 This option allows certain base kernel options and settings
1528 to be disabled or tweaked. This is !! 1097 to be disabled or tweaked. This is for specialized
1529 environments which can tolerate a " !! 1098 environments which can tolerate a "non-standard" kernel.
1530 Only use this if you really know wh !! 1099 Only use this if you really know what you are doing.
1531 1100
1532 config UID16 1101 config UID16
1533 bool "Enable 16-bit UID system calls" 1102 bool "Enable 16-bit UID system calls" if EXPERT
1534 depends on HAVE_UID16 && MULTIUSER 1103 depends on HAVE_UID16 && MULTIUSER
1535 default y 1104 default y
1536 help 1105 help
1537 This enables the legacy 16-bit UID 1106 This enables the legacy 16-bit UID syscall wrappers.
1538 1107
1539 config MULTIUSER 1108 config MULTIUSER
1540 bool "Multiple users, groups and capa 1109 bool "Multiple users, groups and capabilities support" if EXPERT
1541 default y 1110 default y
1542 help 1111 help
1543 This option enables support for non 1112 This option enables support for non-root users, groups and
1544 capabilities. 1113 capabilities.
1545 1114
1546 If you say N here, all processes wi 1115 If you say N here, all processes will run with UID 0, GID 0, and all
1547 possible capabilities. Saying N he 1116 possible capabilities. Saying N here also compiles out support for
1548 system calls related to UIDs, GIDs, 1117 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1549 setgid, and capset. 1118 setgid, and capset.
1550 1119
1551 If unsure, say Y here. 1120 If unsure, say Y here.
1552 1121
1553 config SGETMASK_SYSCALL 1122 config SGETMASK_SYSCALL
1554 bool "sgetmask/ssetmask syscalls supp 1123 bool "sgetmask/ssetmask syscalls support" if EXPERT
1555 default PARISC || M68K || PPC || MIPS !! 1124 def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH
1556 help !! 1125 ---help---
1557 sys_sgetmask and sys_ssetmask are o 1126 sys_sgetmask and sys_ssetmask are obsolete system calls
1558 no longer supported in libc but sti 1127 no longer supported in libc but still enabled by default in some
1559 architectures. 1128 architectures.
1560 1129
1561 If unsure, leave the default option 1130 If unsure, leave the default option here.
1562 1131
1563 config SYSFS_SYSCALL 1132 config SYSFS_SYSCALL
1564 bool "Sysfs syscall support" if EXPER 1133 bool "Sysfs syscall support" if EXPERT
1565 default y 1134 default y
1566 help !! 1135 ---help---
1567 sys_sysfs is an obsolete system cal 1136 sys_sysfs is an obsolete system call no longer supported in libc.
1568 Note that disabling this option is 1137 Note that disabling this option is more secure but might break
1569 compatibility with some systems. 1138 compatibility with some systems.
1570 1139
1571 If unsure say Y here. 1140 If unsure say Y here.
1572 1141
1573 config FHANDLE !! 1142 config SYSCTL_SYSCALL
1574 bool "open by fhandle syscalls" if EX !! 1143 bool "Sysctl syscall support" if EXPERT
1575 select EXPORTFS !! 1144 depends on PROC_SYSCTL
1576 default y !! 1145 default n
1577 help !! 1146 select SYSCTL
1578 If you say Y here, a user level pro !! 1147 ---help---
1579 file names to handle and then later !! 1148 sys_sysctl uses binary paths that have been found challenging
1580 different file system operations. T !! 1149 to properly maintain and use. The interface in /proc/sys
1581 userspace file servers, which now t !! 1150 using paths with ascii names is now the primary path to this
1582 of names. The handle would remain t !! 1151 information.
1583 get renamed. Enables open_by_handle !! 1152
1584 syscalls. !! 1153 Almost nothing using the binary sysctl interface so if you are
>> 1154 trying to save some space it is probably safe to disable this,
>> 1155 making your kernel marginally smaller.
>> 1156
>> 1157 If unsure say N here.
1585 1158
1586 config POSIX_TIMERS 1159 config POSIX_TIMERS
1587 bool "Posix Clocks & timers" if EXPER 1160 bool "Posix Clocks & timers" if EXPERT
1588 default y 1161 default y
1589 help 1162 help
1590 This includes native support for PO 1163 This includes native support for POSIX timers to the kernel.
1591 Some embedded systems have no use f 1164 Some embedded systems have no use for them and therefore they
1592 can be configured out to reduce the 1165 can be configured out to reduce the size of the kernel image.
1593 1166
1594 When this option is disabled, the f 1167 When this option is disabled, the following syscalls won't be
1595 available: timer_create, timer_gett 1168 available: timer_create, timer_gettime: timer_getoverrun,
1596 timer_settime, timer_delete, clock_ 1169 timer_settime, timer_delete, clock_adjtime, getitimer,
1597 setitimer, alarm. Furthermore, the 1170 setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
1598 clock_getres and clock_nanosleep sy 1171 clock_getres and clock_nanosleep syscalls will be limited to
1599 CLOCK_REALTIME, CLOCK_MONOTONIC and 1172 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
1600 1173
1601 If unsure say y. 1174 If unsure say y.
1602 1175
>> 1176 config KALLSYMS
>> 1177 bool "Load all symbols for debugging/ksymoops" if EXPERT
>> 1178 default y
>> 1179 help
>> 1180 Say Y here to let the kernel print out symbolic crash information and
>> 1181 symbolic stack backtraces. This increases the size of the kernel
>> 1182 somewhat, as all symbols have to be loaded into the kernel image.
>> 1183
>> 1184 config KALLSYMS_ALL
>> 1185 bool "Include all symbols in kallsyms"
>> 1186 depends on DEBUG_KERNEL && KALLSYMS
>> 1187 help
>> 1188 Normally kallsyms only contains the symbols of functions for nicer
>> 1189 OOPS messages and backtraces (i.e., symbols from the text and inittext
>> 1190 sections). This is sufficient for most cases. And only in very rare
>> 1191 cases (e.g., when a debugger is used) all symbols are required (e.g.,
>> 1192 names of variables from the data sections, etc).
>> 1193
>> 1194 This option makes sure that all symbols are loaded into the kernel
>> 1195 image (i.e., symbols from all sections) in cost of increased kernel
>> 1196 size (depending on the kernel configuration, it may be 300KiB or
>> 1197 something like this).
>> 1198
>> 1199 Say N unless you really need all symbols.
>> 1200
>> 1201 config KALLSYMS_ABSOLUTE_PERCPU
>> 1202 bool
>> 1203 depends on KALLSYMS
>> 1204 default X86_64 && SMP
>> 1205
>> 1206 config KALLSYMS_BASE_RELATIVE
>> 1207 bool
>> 1208 depends on KALLSYMS
>> 1209 default !IA64 && !(TILE && 64BIT)
>> 1210 help
>> 1211 Instead of emitting them as absolute values in the native word size,
>> 1212 emit the symbol references in the kallsyms table as 32-bit entries,
>> 1213 each containing a relative value in the range [base, base + U32_MAX]
>> 1214 or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either
>> 1215 an absolute value in the range [0, S32_MAX] or a relative value in the
>> 1216 range [base, base + S32_MAX], where base is the lowest relative symbol
>> 1217 address encountered in the image.
>> 1218
>> 1219 On 64-bit builds, this reduces the size of the address table by 50%,
>> 1220 but more importantly, it results in entries whose values are build
>> 1221 time constants, and no relocation pass is required at runtime to fix
>> 1222 up the entries based on the runtime load address of the kernel.
>> 1223
1603 config PRINTK 1224 config PRINTK
1604 default y 1225 default y
1605 bool "Enable support for printk" if E 1226 bool "Enable support for printk" if EXPERT
1606 select IRQ_WORK 1227 select IRQ_WORK
1607 help 1228 help
1608 This option enables normal printk s 1229 This option enables normal printk support. Removing it
1609 eliminates most of the message stri 1230 eliminates most of the message strings from the kernel image
1610 and makes the kernel more or less s 1231 and makes the kernel more or less silent. As this makes it
1611 very difficult to diagnose system p 1232 very difficult to diagnose system problems, saying N here is
1612 strongly discouraged. 1233 strongly discouraged.
1613 1234
>> 1235 config PRINTK_NMI
>> 1236 def_bool y
>> 1237 depends on PRINTK
>> 1238 depends on HAVE_NMI
>> 1239
1614 config BUG 1240 config BUG
1615 bool "BUG() support" if EXPERT 1241 bool "BUG() support" if EXPERT
1616 default y 1242 default y
1617 help 1243 help
1618 Disabling this option eliminates su !! 1244 Disabling this option eliminates support for BUG and WARN, reducing
1619 the size of your kernel image and p !! 1245 the size of your kernel image and potentially quietly ignoring
1620 numerous fatal conditions. You shou !! 1246 numerous fatal conditions. You should only consider disabling this
1621 option for embedded systems with no !! 1247 option for embedded systems with no facilities for reporting errors.
1622 Just say Y. !! 1248 Just say Y.
1623 1249
1624 config ELF_CORE 1250 config ELF_CORE
1625 depends on COREDUMP 1251 depends on COREDUMP
1626 default y 1252 default y
1627 bool "Enable ELF core dumps" if EXPER 1253 bool "Enable ELF core dumps" if EXPERT
1628 help 1254 help
1629 Enable support for generating core 1255 Enable support for generating core dumps. Disabling saves about 4k.
1630 1256
1631 1257
1632 config PCSPKR_PLATFORM 1258 config PCSPKR_PLATFORM
1633 bool "Enable PC-Speaker support" if E 1259 bool "Enable PC-Speaker support" if EXPERT
1634 depends on HAVE_PCSPKR_PLATFORM 1260 depends on HAVE_PCSPKR_PLATFORM
1635 select I8253_LOCK 1261 select I8253_LOCK
1636 default y 1262 default y
1637 help 1263 help
1638 This option allows to disable the i !! 1264 This option allows to disable the internal PC-Speaker
1639 support, saving some memory. !! 1265 support, saving some memory.
1640 1266
1641 config BASE_SMALL !! 1267 config BASE_FULL
1642 bool "Enable smaller-sized data struc !! 1268 default y
>> 1269 bool "Enable full-sized data structures for core" if EXPERT
1643 help 1270 help
1644 Enabling this option reduces the si !! 1271 Disabling this option reduces the size of miscellaneous core
1645 kernel data structures. This saves 1272 kernel data structures. This saves memory on small machines,
1646 but may reduce performance. 1273 but may reduce performance.
1647 1274
1648 config FUTEX 1275 config FUTEX
1649 bool "Enable futex support" if EXPERT 1276 bool "Enable futex support" if EXPERT
1650 depends on !(SPARC32 && SMP) <<
1651 default y 1277 default y
1652 imply RT_MUTEXES 1278 imply RT_MUTEXES
1653 help 1279 help
1654 Disabling this option will cause th 1280 Disabling this option will cause the kernel to be built without
1655 support for "fast userspace mutexes 1281 support for "fast userspace mutexes". The resulting kernel may not
1656 run glibc-based applications correc 1282 run glibc-based applications correctly.
1657 1283
1658 config FUTEX_PI 1284 config FUTEX_PI
1659 bool 1285 bool
1660 depends on FUTEX && RT_MUTEXES 1286 depends on FUTEX && RT_MUTEXES
1661 default y 1287 default y
1662 1288
>> 1289 config HAVE_FUTEX_CMPXCHG
>> 1290 bool
>> 1291 depends on FUTEX
>> 1292 help
>> 1293 Architectures should select this if futex_atomic_cmpxchg_inatomic()
>> 1294 is implemented and always working. This removes a couple of runtime
>> 1295 checks.
>> 1296
1663 config EPOLL 1297 config EPOLL
1664 bool "Enable eventpoll support" if EX 1298 bool "Enable eventpoll support" if EXPERT
1665 default y 1299 default y
>> 1300 select ANON_INODES
1666 help 1301 help
1667 Disabling this option will cause th 1302 Disabling this option will cause the kernel to be built without
1668 support for epoll family of system 1303 support for epoll family of system calls.
1669 1304
1670 config SIGNALFD 1305 config SIGNALFD
1671 bool "Enable signalfd() system call" 1306 bool "Enable signalfd() system call" if EXPERT
>> 1307 select ANON_INODES
1672 default y 1308 default y
1673 help 1309 help
1674 Enable the signalfd() system call t 1310 Enable the signalfd() system call that allows to receive signals
1675 on a file descriptor. 1311 on a file descriptor.
1676 1312
1677 If unsure, say Y. 1313 If unsure, say Y.
1678 1314
1679 config TIMERFD 1315 config TIMERFD
1680 bool "Enable timerfd() system call" i 1316 bool "Enable timerfd() system call" if EXPERT
>> 1317 select ANON_INODES
1681 default y 1318 default y
1682 help 1319 help
1683 Enable the timerfd() system call th 1320 Enable the timerfd() system call that allows to receive timer
1684 events on a file descriptor. 1321 events on a file descriptor.
1685 1322
1686 If unsure, say Y. 1323 If unsure, say Y.
1687 1324
1688 config EVENTFD 1325 config EVENTFD
1689 bool "Enable eventfd() system call" i 1326 bool "Enable eventfd() system call" if EXPERT
>> 1327 select ANON_INODES
1690 default y 1328 default y
1691 help 1329 help
1692 Enable the eventfd() system call th 1330 Enable the eventfd() system call that allows to receive both
1693 kernel notification (ie. KAIO) or u 1331 kernel notification (ie. KAIO) or userspace notifications.
1694 1332
1695 If unsure, say Y. 1333 If unsure, say Y.
1696 1334
>> 1335 # syscall, maps, verifier
>> 1336 config BPF_SYSCALL
>> 1337 bool "Enable bpf() system call"
>> 1338 select ANON_INODES
>> 1339 select BPF
>> 1340 default n
>> 1341 help
>> 1342 Enable the bpf() system call that allows to manipulate eBPF
>> 1343 programs and maps via file descriptors.
>> 1344
>> 1345 config BPF_JIT_ALWAYS_ON
>> 1346 bool "Permanently enable BPF JIT and remove BPF interpreter"
>> 1347 depends on BPF_SYSCALL && HAVE_EBPF_JIT && BPF_JIT
>> 1348 help
>> 1349 Enables BPF JIT and removes BPF interpreter to avoid
>> 1350 speculative execution of BPF instructions by the interpreter
>> 1351
1697 config SHMEM 1352 config SHMEM
1698 bool "Use full shmem filesystem" if E 1353 bool "Use full shmem filesystem" if EXPERT
1699 default y 1354 default y
1700 depends on MMU 1355 depends on MMU
1701 help 1356 help
1702 The shmem is an internal filesystem 1357 The shmem is an internal filesystem used to manage shared memory.
1703 It is backed by swap and manages re 1358 It is backed by swap and manages resource limits. It is also exported
1704 to userspace as tmpfs if TMPFS is e 1359 to userspace as tmpfs if TMPFS is enabled. Disabling this
1705 option replaces shmem and tmpfs wit 1360 option replaces shmem and tmpfs with the much simpler ramfs code,
1706 which may be appropriate on small s 1361 which may be appropriate on small systems without swap.
1707 1362
1708 config AIO 1363 config AIO
1709 bool "Enable AIO support" if EXPERT 1364 bool "Enable AIO support" if EXPERT
1710 default y 1365 default y
1711 help 1366 help
1712 This option enables POSIX asynchron 1367 This option enables POSIX asynchronous I/O which may by used
1713 by some high performance threaded a 1368 by some high performance threaded applications. Disabling
1714 this option saves about 7k. 1369 this option saves about 7k.
1715 1370
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 1371 config ADVISE_SYSCALLS
1739 bool "Enable madvise/fadvise syscalls 1372 bool "Enable madvise/fadvise syscalls" if EXPERT
1740 default y 1373 default y
1741 help 1374 help
1742 This option enables the madvise and 1375 This option enables the madvise and fadvise syscalls, used by
1743 applications to advise the kernel a 1376 applications to advise the kernel about their future memory or file
1744 usage, improving performance. If bu 1377 usage, improving performance. If building an embedded system where no
1745 applications use these syscalls, yo 1378 applications use these syscalls, you can disable this option to save
1746 space. 1379 space.
1747 1380
>> 1381 config BPF_UNPRIV_DEFAULT_OFF
>> 1382 bool "Disable unprivileged BPF by default"
>> 1383 depends on BPF_SYSCALL
>> 1384 help
>> 1385 Disables unprivileged BPF by default by setting the corresponding
>> 1386 /proc/sys/kernel/unprivileged_bpf_disabled knob to 2. An admin can
>> 1387 still reenable it by setting it to 0 later on, or permanently
>> 1388 disable it by setting it to 1 (from which no other transition to
>> 1389 0 is possible anymore).
>> 1390
>> 1391 config USERFAULTFD
>> 1392 bool "Enable userfaultfd() system call"
>> 1393 select ANON_INODES
>> 1394 depends on MMU
>> 1395 help
>> 1396 Enable the userfaultfd() system call that allows to intercept and
>> 1397 handle page faults in userland.
>> 1398
>> 1399 config PCI_QUIRKS
>> 1400 default y
>> 1401 bool "Enable PCI quirk workarounds" if EXPERT
>> 1402 depends on PCI
>> 1403 help
>> 1404 This enables workarounds for various PCI chipset
>> 1405 bugs/quirks. Disable this only if your target machine is
>> 1406 unaffected by PCI quirks.
>> 1407
1748 config MEMBARRIER 1408 config MEMBARRIER
1749 bool "Enable membarrier() system call 1409 bool "Enable membarrier() system call" if EXPERT
1750 default y 1410 default y
1751 help 1411 help
1752 Enable the membarrier() system call 1412 Enable the membarrier() system call that allows issuing memory
1753 barriers across all running threads 1413 barriers across all running threads, which can be used to distribute
1754 the cost of user-space memory barri 1414 the cost of user-space memory barriers asymmetrically by transforming
1755 pairs of memory barriers into pairs 1415 pairs of memory barriers into pairs consisting of membarrier() and a
1756 compiler barrier. 1416 compiler barrier.
1757 1417
1758 If unsure, say Y. 1418 If unsure, say Y.
1759 1419
1760 config KCMP !! 1420 config EMBEDDED
1761 bool "Enable kcmp() system call" if E !! 1421 bool "Embedded system"
1762 help !! 1422 option allnoconfig_y
1763 Enable the kernel resource comparis !! 1423 select EXPERT
1764 user-space with the ability to comp !! 1424 help
1765 share a common resource, such as a !! 1425 This option should be enabled if compiling the kernel for
1766 memory space. !! 1426 an embedded system so certain expert options are available
1767 !! 1427 for configuration.
1768 If unsure, say N. <<
1769 <<
1770 config RSEQ <<
1771 bool "Enable rseq() system call" if E <<
1772 default y <<
1773 depends on HAVE_RSEQ <<
1774 select MEMBARRIER <<
1775 help <<
1776 Enable the restartable sequences sy <<
1777 user-space cache for the current CP <<
1778 speeds up getting the current CPU n <<
1779 as well as an ABI to speed up user- <<
1780 per-CPU data. <<
1781 <<
1782 If unsure, say Y. <<
1783 <<
1784 config DEBUG_RSEQ <<
1785 default n <<
1786 bool "Enable debugging of rseq() syst <<
1787 depends on RSEQ && DEBUG_KERNEL <<
1788 help <<
1789 Enable extra debugging checks for t <<
1790 <<
1791 If unsure, say N. <<
1792 <<
1793 config CACHESTAT_SYSCALL <<
1794 bool "Enable cachestat() system call" <<
1795 default y <<
1796 help <<
1797 Enable the cachestat system call, w <<
1798 statistics of a file (number of cac <<
1799 pages marked for writeback, (recent <<
1800 <<
1801 If unsure say Y here. <<
1802 <<
1803 config PC104 <<
1804 bool "PC/104 support" if EXPERT <<
1805 help <<
1806 Expose PC/104 form factor device dr <<
1807 selection and configuration. Enable <<
1808 machine has a PC/104 bus. <<
1809 <<
1810 config KALLSYMS <<
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 1428
1862 config HAVE_PERF_EVENTS 1429 config HAVE_PERF_EVENTS
1863 bool 1430 bool
1864 help 1431 help
1865 See tools/perf/design.txt for detai 1432 See tools/perf/design.txt for details.
1866 1433
1867 config GUEST_PERF_EVENTS <<
1868 bool <<
1869 depends on HAVE_PERF_EVENTS <<
1870 <<
1871 config PERF_USE_VMALLOC 1434 config PERF_USE_VMALLOC
1872 bool 1435 bool
1873 help 1436 help
1874 See tools/perf/design.txt for detai 1437 See tools/perf/design.txt for details
1875 1438
>> 1439 config PC104
>> 1440 bool "PC/104 support"
>> 1441 help
>> 1442 Expose PC/104 form factor device drivers and options available for
>> 1443 selection and configuration. Enable this option if your target
>> 1444 machine has a PC/104 bus.
>> 1445
1876 menu "Kernel Performance Events And Counters" 1446 menu "Kernel Performance Events And Counters"
1877 1447
1878 config PERF_EVENTS 1448 config PERF_EVENTS
1879 bool "Kernel performance events and c 1449 bool "Kernel performance events and counters"
1880 default y if PROFILING 1450 default y if PROFILING
1881 depends on HAVE_PERF_EVENTS 1451 depends on HAVE_PERF_EVENTS
>> 1452 select ANON_INODES
1882 select IRQ_WORK 1453 select IRQ_WORK
>> 1454 select SRCU
1883 help 1455 help
1884 Enable kernel support for various p 1456 Enable kernel support for various performance events provided
1885 by software and hardware. 1457 by software and hardware.
1886 1458
1887 Software events are supported eithe 1459 Software events are supported either built-in or via the
1888 use of generic tracepoints. 1460 use of generic tracepoints.
1889 1461
1890 Most modern CPUs support performanc 1462 Most modern CPUs support performance events via performance
1891 counter registers. These registers 1463 counter registers. These registers count the number of certain
1892 types of hw events: such as instruc 1464 types of hw events: such as instructions executed, cachemisses
1893 suffered, or branches mis-predicted 1465 suffered, or branches mis-predicted - without slowing down the
1894 kernel or applications. These regis 1466 kernel or applications. These registers can also trigger interrupts
1895 when a threshold number of events h 1467 when a threshold number of events have passed - and can thus be
1896 used to profile the code that runs 1468 used to profile the code that runs on that CPU.
1897 1469
1898 The Linux Performance Event subsyst 1470 The Linux Performance Event subsystem provides an abstraction of
1899 these software and hardware event c 1471 these software and hardware event capabilities, available via a
1900 system call and used by the "perf" 1472 system call and used by the "perf" utility in tools/perf/. It
1901 provides per task and per CPU count 1473 provides per task and per CPU counters, and it provides event
1902 capabilities on top of those. 1474 capabilities on top of those.
1903 1475
1904 Say Y if unsure. 1476 Say Y if unsure.
1905 1477
1906 config DEBUG_PERF_USE_VMALLOC 1478 config DEBUG_PERF_USE_VMALLOC
1907 default n 1479 default n
1908 bool "Debug: use vmalloc to back perf 1480 bool "Debug: use vmalloc to back perf mmap() buffers"
1909 depends on PERF_EVENTS && DEBUG_KERNE 1481 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
1910 select PERF_USE_VMALLOC 1482 select PERF_USE_VMALLOC
1911 help 1483 help
1912 Use vmalloc memory to back perf mma !! 1484 Use vmalloc memory to back perf mmap() buffers.
1913 1485
1914 Mostly useful for debugging the vma !! 1486 Mostly useful for debugging the vmalloc code on platforms
1915 that don't require it. !! 1487 that don't require it.
1916 1488
1917 Say N if unsure. !! 1489 Say N if unsure.
1918 1490
1919 endmenu 1491 endmenu
1920 1492
>> 1493 config VM_EVENT_COUNTERS
>> 1494 default y
>> 1495 bool "Enable VM event counters for /proc/vmstat" if EXPERT
>> 1496 help
>> 1497 VM event counters are needed for event counts to be shown.
>> 1498 This option allows the disabling of the VM event counters
>> 1499 on EXPERT systems. /proc/vmstat will only show page counts
>> 1500 if VM event counters are disabled.
>> 1501
>> 1502 config SLUB_DEBUG
>> 1503 default y
>> 1504 bool "Enable SLUB debugging support" if EXPERT
>> 1505 depends on SLUB && SYSFS
>> 1506 help
>> 1507 SLUB has extensive debug support features. Disabling these can
>> 1508 result in significant savings in code size. This also disables
>> 1509 SLUB sysfs support. /sys/slab will not exist and there will be
>> 1510 no support for cache validation etc.
>> 1511
>> 1512 config SLUB_MEMCG_SYSFS_ON
>> 1513 default n
>> 1514 bool "Enable memcg SLUB sysfs support by default" if EXPERT
>> 1515 depends on SLUB && SYSFS && MEMCG
>> 1516 help
>> 1517 SLUB creates a directory under /sys/kernel/slab for each
>> 1518 allocation cache to host info and debug files. If memory
>> 1519 cgroup is enabled, each cache can have per memory cgroup
>> 1520 caches. SLUB can create the same sysfs directories for these
>> 1521 caches under /sys/kernel/slab/CACHE/cgroup but it can lead
>> 1522 to a very high number of debug files being created. This is
>> 1523 controlled by slub_memcg_sysfs boot parameter and this
>> 1524 config option determines the parameter's default value.
>> 1525
>> 1526 config COMPAT_BRK
>> 1527 bool "Disable heap randomization"
>> 1528 default y
>> 1529 help
>> 1530 Randomizing heap placement makes heap exploits harder, but it
>> 1531 also breaks ancient binaries (including anything libc5 based).
>> 1532 This option changes the bootup default to heap randomization
>> 1533 disabled, and can be overridden at runtime by setting
>> 1534 /proc/sys/kernel/randomize_va_space to 2.
>> 1535
>> 1536 On non-ancient distros (post-2000 ones) N is usually a safe choice.
>> 1537
>> 1538 choice
>> 1539 prompt "Choose SLAB allocator"
>> 1540 default SLUB
>> 1541 help
>> 1542 This option allows to select a slab allocator.
>> 1543
>> 1544 config SLAB
>> 1545 bool "SLAB"
>> 1546 select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 1547 help
>> 1548 The regular slab allocator that is established and known to work
>> 1549 well in all environments. It organizes cache hot objects in
>> 1550 per cpu and per node queues.
>> 1551
>> 1552 config SLUB
>> 1553 bool "SLUB (Unqueued Allocator)"
>> 1554 select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 1555 help
>> 1556 SLUB is a slab allocator that minimizes cache line usage
>> 1557 instead of managing queues of cached objects (SLAB approach).
>> 1558 Per cpu caching is realized using slabs of objects instead
>> 1559 of queues of objects. SLUB can use memory efficiently
>> 1560 and has enhanced diagnostics. SLUB is the default choice for
>> 1561 a slab allocator.
>> 1562
>> 1563 config SLOB
>> 1564 depends on EXPERT
>> 1565 bool "SLOB (Simple Allocator)"
>> 1566 help
>> 1567 SLOB replaces the stock allocator with a drastically simpler
>> 1568 allocator. SLOB is generally more space efficient but
>> 1569 does not perform as well on large systems.
>> 1570
>> 1571 endchoice
>> 1572
>> 1573 config SLAB_MERGE_DEFAULT
>> 1574 bool "Allow slab caches to be merged"
>> 1575 default y
>> 1576 help
>> 1577 For reduced kernel memory fragmentation, slab caches can be
>> 1578 merged when they share the same size and other characteristics.
>> 1579 This carries a risk of kernel heap overflows being able to
>> 1580 overwrite objects from merged caches (and more easily control
>> 1581 cache layout), which makes such heap attacks easier to exploit
>> 1582 by attackers. By keeping caches unmerged, these kinds of exploits
>> 1583 can usually only damage objects in the same cache. To disable
>> 1584 merging at runtime, "slab_nomerge" can be passed on the kernel
>> 1585 command line.
>> 1586
>> 1587 config SLAB_FREELIST_RANDOM
>> 1588 default n
>> 1589 depends on SLAB || SLUB
>> 1590 bool "SLAB freelist randomization"
>> 1591 help
>> 1592 Randomizes the freelist order used on creating new pages. This
>> 1593 security feature reduces the predictability of the kernel slab
>> 1594 allocator against heap overflows.
>> 1595
>> 1596 config SLAB_FREELIST_HARDENED
>> 1597 bool "Harden slab freelist metadata"
>> 1598 depends on SLUB
>> 1599 help
>> 1600 Many kernel heap attacks try to target slab cache metadata and
>> 1601 other infrastructure. This options makes minor performance
>> 1602 sacrifies to harden the kernel slab allocator against common
>> 1603 freelist exploit methods.
>> 1604
>> 1605 config SLUB_CPU_PARTIAL
>> 1606 default y
>> 1607 depends on SLUB && SMP
>> 1608 bool "SLUB per cpu partial cache"
>> 1609 help
>> 1610 Per cpu partial caches accellerate objects allocation and freeing
>> 1611 that is local to a processor at the price of more indeterminism
>> 1612 in the latency of the free. On overflow these caches will be cleared
>> 1613 which requires the taking of locks that may cause latency spikes.
>> 1614 Typically one would choose no for a realtime system.
>> 1615
>> 1616 config MMAP_ALLOW_UNINITIALIZED
>> 1617 bool "Allow mmapped anonymous memory to be uninitialized"
>> 1618 depends on EXPERT && !MMU
>> 1619 default n
>> 1620 help
>> 1621 Normally, and according to the Linux spec, anonymous memory obtained
>> 1622 from mmap() has it's contents cleared before it is passed to
>> 1623 userspace. Enabling this config option allows you to request that
>> 1624 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
>> 1625 providing a huge performance boost. If this option is not enabled,
>> 1626 then the flag will be ignored.
>> 1627
>> 1628 This is taken advantage of by uClibc's malloc(), and also by
>> 1629 ELF-FDPIC binfmt's brk and stack allocator.
>> 1630
>> 1631 Because of the obvious security issues, this option should only be
>> 1632 enabled on embedded devices where you control what is run in
>> 1633 userspace. Since that isn't generally a problem on no-MMU systems,
>> 1634 it is normally safe to say Y here.
>> 1635
>> 1636 See Documentation/nommu-mmap.txt for more information.
>> 1637
1921 config SYSTEM_DATA_VERIFICATION 1638 config SYSTEM_DATA_VERIFICATION
1922 def_bool n 1639 def_bool n
1923 select SYSTEM_TRUSTED_KEYRING 1640 select SYSTEM_TRUSTED_KEYRING
1924 select KEYS 1641 select KEYS
1925 select CRYPTO 1642 select CRYPTO
1926 select CRYPTO_RSA 1643 select CRYPTO_RSA
1927 select ASYMMETRIC_KEY_TYPE 1644 select ASYMMETRIC_KEY_TYPE
1928 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 1645 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1929 select ASN1 1646 select ASN1
1930 select OID_REGISTRY 1647 select OID_REGISTRY
1931 select X509_CERTIFICATE_PARSER 1648 select X509_CERTIFICATE_PARSER
1932 select PKCS7_MESSAGE_PARSER 1649 select PKCS7_MESSAGE_PARSER
1933 help 1650 help
1934 Provide PKCS#7 message verification 1651 Provide PKCS#7 message verification using the contents of the system
1935 trusted keyring to provide public k 1652 trusted keyring to provide public keys. This then can be used for
1936 module verification, kexec image ve 1653 module verification, kexec image verification and firmware blob
1937 verification. 1654 verification.
1938 1655
1939 config PROFILING 1656 config PROFILING
1940 bool "Profiling support" 1657 bool "Profiling support"
1941 help 1658 help
1942 Say Y here to enable the extended p 1659 Say Y here to enable the extended profiling support mechanisms used
1943 by profilers. !! 1660 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 1661
1986 # 1662 #
1987 # Place an empty function call at each tracep 1663 # Place an empty function call at each tracepoint site. Can be
1988 # dynamically changed for a probe function. 1664 # dynamically changed for a probe function.
1989 # 1665 #
1990 config TRACEPOINTS 1666 config TRACEPOINTS
1991 bool 1667 bool
1992 1668
1993 source "kernel/Kconfig.kexec" !! 1669 source "arch/Kconfig"
1994 1670
1995 endmenu # General setup 1671 endmenu # General setup
1996 1672
1997 source "arch/Kconfig" !! 1673 config HAVE_GENERIC_DMA_COHERENT
>> 1674 bool
>> 1675 default n
>> 1676
>> 1677 config SLABINFO
>> 1678 bool
>> 1679 depends on PROC_FS
>> 1680 depends on SLAB || SLUB_DEBUG
>> 1681 default y
1998 1682
1999 config RT_MUTEXES 1683 config RT_MUTEXES
2000 bool 1684 bool
2001 default y if PREEMPT_RT <<
2002 1685
2003 config MODULE_SIG_FORMAT !! 1686 config BASE_SMALL
2004 def_bool n !! 1687 int
>> 1688 default 0 if BASE_FULL
>> 1689 default 1 if !BASE_FULL
>> 1690
>> 1691 menuconfig MODULES
>> 1692 bool "Enable loadable module support"
>> 1693 option modules
>> 1694 help
>> 1695 Kernel modules are small pieces of compiled code which can
>> 1696 be inserted in the running kernel, rather than being
>> 1697 permanently built into the kernel. You use the "modprobe"
>> 1698 tool to add (and sometimes remove) them. If you say Y here,
>> 1699 many parts of the kernel can be built as modules (by
>> 1700 answering M instead of Y where indicated): this is most
>> 1701 useful for infrequently used options which are not required
>> 1702 for booting. For more information, see the man pages for
>> 1703 modprobe, lsmod, modinfo, insmod and rmmod.
>> 1704
>> 1705 If you say Y here, you will need to run "make
>> 1706 modules_install" to put the modules under /lib/modules/
>> 1707 where modprobe can find them (you may need to be root to do
>> 1708 this).
>> 1709
>> 1710 If unsure, say Y.
>> 1711
>> 1712 if MODULES
>> 1713
>> 1714 config MODULE_FORCE_LOAD
>> 1715 bool "Forced module loading"
>> 1716 default n
>> 1717 help
>> 1718 Allow loading of modules without version information (ie. modprobe
>> 1719 --force). Forced module loading sets the 'F' (forced) taint flag and
>> 1720 is usually a really bad idea.
>> 1721
>> 1722 config MODULE_UNLOAD
>> 1723 bool "Module unloading"
>> 1724 help
>> 1725 Without this option you will not be able to unload any
>> 1726 modules (note that some modules may not be unloadable
>> 1727 anyway), which makes your kernel smaller, faster
>> 1728 and simpler. If unsure, say Y.
>> 1729
>> 1730 config MODULE_FORCE_UNLOAD
>> 1731 bool "Forced module unloading"
>> 1732 depends on MODULE_UNLOAD
>> 1733 help
>> 1734 This option allows you to force a module to unload, even if the
>> 1735 kernel believes it is unsafe: the kernel will remove the module
>> 1736 without waiting for anyone to stop using it (using the -f option to
>> 1737 rmmod). This is mainly for kernel developers and desperate users.
>> 1738 If unsure, say N.
>> 1739
>> 1740 config MODVERSIONS
>> 1741 bool "Module versioning support"
>> 1742 help
>> 1743 Usually, you have to use modules compiled with your kernel.
>> 1744 Saying Y here makes it sometimes possible to use modules
>> 1745 compiled for different kernels, by adding enough information
>> 1746 to the modules to (hopefully) spot any changes which would
>> 1747 make them incompatible with the kernel you are running. If
>> 1748 unsure, say N.
>> 1749
>> 1750 config MODULE_REL_CRCS
>> 1751 bool
>> 1752 depends on MODVERSIONS
>> 1753
>> 1754 config MODULE_SRCVERSION_ALL
>> 1755 bool "Source checksum for all modules"
>> 1756 help
>> 1757 Modules which contain a MODULE_VERSION get an extra "srcversion"
>> 1758 field inserted into their modinfo section, which contains a
>> 1759 sum of the source files which made it. This helps maintainers
>> 1760 see exactly which source was used to build a module (since
>> 1761 others sometimes change the module source without updating
>> 1762 the version). With this option, such a "srcversion" field
>> 1763 will be created for all modules. If unsure, say N.
>> 1764
>> 1765 config MODULE_SIG
>> 1766 bool "Module signature verification"
>> 1767 depends on MODULES
2005 select SYSTEM_DATA_VERIFICATION 1768 select SYSTEM_DATA_VERIFICATION
>> 1769 help
>> 1770 Check modules for valid signatures upon load: the signature
>> 1771 is simply appended to the module. For more information see
>> 1772 Documentation/module-signing.txt.
>> 1773
>> 1774 Note that this option adds the OpenSSL development packages as a
>> 1775 kernel build dependency so that the signing tool can use its crypto
>> 1776 library.
>> 1777
>> 1778 !!!WARNING!!! If you enable this option, you MUST make sure that the
>> 1779 module DOES NOT get stripped after being signed. This includes the
>> 1780 debuginfo strip done by some packagers (such as rpmbuild) and
>> 1781 inclusion into an initramfs that wants the module size reduced.
>> 1782
>> 1783 config MODULE_SIG_FORCE
>> 1784 bool "Require modules to be validly signed"
>> 1785 depends on MODULE_SIG
>> 1786 help
>> 1787 Reject unsigned modules or signed modules for which we don't have a
>> 1788 key. Without this, such modules will simply taint the kernel.
>> 1789
>> 1790 config MODULE_SIG_ALL
>> 1791 bool "Automatically sign all modules"
>> 1792 default y
>> 1793 depends on MODULE_SIG
>> 1794 help
>> 1795 Sign all modules during make modules_install. Without this option,
>> 1796 modules must be signed manually, using the scripts/sign-file tool.
>> 1797
>> 1798 comment "Do not forget to sign required modules with scripts/sign-file"
>> 1799 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
>> 1800
>> 1801 choice
>> 1802 prompt "Which hash algorithm should modules be signed with?"
>> 1803 depends on MODULE_SIG
>> 1804 help
>> 1805 This determines which sort of hashing algorithm will be used during
>> 1806 signature generation. This algorithm _must_ be built into the kernel
>> 1807 directly so that signature verification can take place. It is not
>> 1808 possible to load a signed module containing the algorithm to check
>> 1809 the signature on that module.
>> 1810
>> 1811 config MODULE_SIG_SHA1
>> 1812 bool "Sign modules with SHA-1"
>> 1813 select CRYPTO_SHA1
>> 1814
>> 1815 config MODULE_SIG_SHA224
>> 1816 bool "Sign modules with SHA-224"
>> 1817 select CRYPTO_SHA256
>> 1818
>> 1819 config MODULE_SIG_SHA256
>> 1820 bool "Sign modules with SHA-256"
>> 1821 select CRYPTO_SHA256
>> 1822
>> 1823 config MODULE_SIG_SHA384
>> 1824 bool "Sign modules with SHA-384"
>> 1825 select CRYPTO_SHA512
>> 1826
>> 1827 config MODULE_SIG_SHA512
>> 1828 bool "Sign modules with SHA-512"
>> 1829 select CRYPTO_SHA512
>> 1830
>> 1831 endchoice
>> 1832
>> 1833 config MODULE_SIG_HASH
>> 1834 string
>> 1835 depends on MODULE_SIG
>> 1836 default "sha1" if MODULE_SIG_SHA1
>> 1837 default "sha224" if MODULE_SIG_SHA224
>> 1838 default "sha256" if MODULE_SIG_SHA256
>> 1839 default "sha384" if MODULE_SIG_SHA384
>> 1840 default "sha512" if MODULE_SIG_SHA512
>> 1841
>> 1842 config MODULE_COMPRESS
>> 1843 bool "Compress modules on installation"
>> 1844 depends on MODULES
>> 1845 help
2006 1846
2007 source "kernel/module/Kconfig" !! 1847 Compresses kernel modules when 'make modules_install' is run; gzip or
>> 1848 xz depending on "Compression algorithm" below.
>> 1849
>> 1850 module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
>> 1851
>> 1852 Out-of-tree kernel modules installed using Kbuild will also be
>> 1853 compressed upon installation.
>> 1854
>> 1855 Note: for modules inside an initrd or initramfs, it's more efficient
>> 1856 to compress the whole initrd or initramfs instead.
>> 1857
>> 1858 Note: This is fully compatible with signed modules.
>> 1859
>> 1860 If in doubt, say N.
>> 1861
>> 1862 choice
>> 1863 prompt "Compression algorithm"
>> 1864 depends on MODULE_COMPRESS
>> 1865 default MODULE_COMPRESS_GZIP
>> 1866 help
>> 1867 This determines which sort of compression will be used during
>> 1868 'make modules_install'.
>> 1869
>> 1870 GZIP (default) and XZ are supported.
>> 1871
>> 1872 config MODULE_COMPRESS_GZIP
>> 1873 bool "GZIP"
>> 1874
>> 1875 config MODULE_COMPRESS_XZ
>> 1876 bool "XZ"
>> 1877
>> 1878 endchoice
>> 1879
>> 1880 config TRIM_UNUSED_KSYMS
>> 1881 bool "Trim unused exported kernel symbols"
>> 1882 depends on MODULES && !UNUSED_SYMBOLS
>> 1883 help
>> 1884 The kernel and some modules make many symbols available for
>> 1885 other modules to use via EXPORT_SYMBOL() and variants. Depending
>> 1886 on the set of modules being selected in your kernel configuration,
>> 1887 many of those exported symbols might never be used.
>> 1888
>> 1889 This option allows for unused exported symbols to be dropped from
>> 1890 the build. In turn, this provides the compiler more opportunities
>> 1891 (especially when using LTO) for optimizing the code and reducing
>> 1892 binary size. This might have some security advantages as well.
>> 1893
>> 1894 If unsure, or if you need to build out-of-tree modules, say N.
>> 1895
>> 1896 endif # MODULES
>> 1897
>> 1898 config MODULES_TREE_LOOKUP
>> 1899 def_bool y
>> 1900 depends on PERF_EVENTS || TRACING
2008 1901
2009 config INIT_ALL_POSSIBLE 1902 config INIT_ALL_POSSIBLE
2010 bool 1903 bool
2011 help 1904 help
2012 Back when each arch used to define 1905 Back when each arch used to define their own cpu_online_mask and
2013 cpu_possible_mask, some of them cho 1906 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
2014 with all 1s, and others with all 0s 1907 with all 1s, and others with all 0s. When they were centralised,
2015 it was better to provide this optio 1908 it was better to provide this option than to break all the archs
2016 and have several arch maintainers p 1909 and have several arch maintainers pursuing me down dark alleys.
2017 1910
2018 source "block/Kconfig" 1911 source "block/Kconfig"
2019 1912
2020 config PREEMPT_NOTIFIERS 1913 config PREEMPT_NOTIFIERS
2021 bool 1914 bool
2022 1915
2023 config PADATA 1916 config PADATA
2024 depends on SMP 1917 depends on SMP
2025 bool 1918 bool
2026 1919
2027 config ASN1 1920 config ASN1
2028 tristate 1921 tristate
2029 help 1922 help
2030 Build a simple ASN.1 grammar compil 1923 Build a simple ASN.1 grammar compiler that produces a bytecode output
2031 that can be interpreted by the ASN. 1924 that can be interpreted by the ASN.1 stream decoder and used to
2032 inform it as to what tags are to be 1925 inform it as to what tags are to be expected in a stream and what
2033 functions to call on what tags. 1926 functions to call on what tags.
2034 1927
2035 source "kernel/Kconfig.locks" 1928 source "kernel/Kconfig.locks"
2036 <<
2037 config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE <<
2038 bool <<
2039 <<
2040 config ARCH_HAS_PREPARE_SYNC_CORE_CMD <<
2041 bool <<
2042 <<
2043 config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE <<
2044 bool <<
2045 <<
2046 # It may be useful for an architecture to ove <<
2047 # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() ma <<
2048 # and the COMPAT_ variants in <linux/compat.h <<
2049 # different calling convention for syscalls. <<
2050 # macros for not-implemented syscalls in kern <<
2051 # kernel/time/posix-stubs.c. All these overri <<
2052 # <asm/syscall_wrapper.h>. <<
2053 config ARCH_HAS_SYSCALL_WRAPPER <<
2054 def_bool n <<
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