| 1 | # SPDX-License-Identifier: GPL-2.0-only |
| 2 | config CC_VERSION_TEXT |
| 3 | string |
| 4 | default "$(CC_VERSION_TEXT)" |
| 5 | help |
| 6 | This is used in unclear ways: |
| 7 | |
| 8 | - Re-run Kconfig when the compiler is updated |
| 9 | The 'default' property references the environment variable, |
| 10 | CC_VERSION_TEXT so it is recorded in include/config/auto.conf.cmd. |
| 11 | When the compiler is updated, Kconfig will be invoked. |
| 12 | |
| 13 | - Ensure full rebuild when the compiler is updated |
| 14 | include/linux/compiler-version.h contains this option in the comment |
| 15 | line so fixdep adds include/config/CC_VERSION_TEXT into the |
| 16 | auto-generated dependency. When the compiler is updated, syncconfig |
| 17 | will touch it and then every file will be rebuilt. |
| 18 | |
| 19 | config CC_IS_GCC |
| 20 | def_bool $(success,test "$(cc-name)" = GCC) |
| 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)" = Clang) |
| 29 | |
| 30 | config CLANG_VERSION |
| 31 | int |
| 32 | default $(cc-version) if CC_IS_CLANG |
| 33 | default 0 |
| 34 | |
| 35 | config AS_IS_GNU |
| 36 | def_bool $(success,test "$(as-name)" = GNU) |
| 37 | |
| 38 | config AS_IS_LLVM |
| 39 | def_bool $(success,test "$(as-name)" = LLVM) |
| 40 | |
| 41 | config AS_VERSION |
| 42 | int |
| 43 | # Use clang version if this is the integrated assembler |
| 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)" = BFD) |
| 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)" = LLD) |
| 57 | |
| 58 | config LLD_VERSION |
| 59 | int |
| 60 | default $(ld-version) if LD_IS_LLD |
| 61 | default 0 |
| 62 | |
| 63 | config RUSTC_VERSION |
| 64 | int |
| 65 | default $(rustc-version) |
| 66 | help |
| 67 | It does not depend on `RUST` since that one may need to use the version |
| 68 | in a `depends on`. |
| 69 | |
| 70 | config RUST_IS_AVAILABLE |
| 71 | def_bool $(success,$(srctree)/scripts/rust_is_available.sh) |
| 72 | help |
| 73 | This shows whether a suitable Rust toolchain is available (found). |
| 74 | |
| 75 | Please see Documentation/rust/quick-start.rst for instructions on how |
| 76 | to satisfy the build requirements of Rust support. |
| 77 | |
| 78 | In particular, the Makefile target 'rustavailable' is useful to check |
| 79 | why the Rust toolchain is not being detected. |
| 80 | |
| 81 | config RUSTC_LLVM_VERSION |
| 82 | int |
| 83 | default $(rustc-llvm-version) |
| 84 | |
| 85 | config RUSTC_LLVM_MAJOR_VERSION |
| 86 | int |
| 87 | default $(shell,expr $(rustc-llvm-version) / 10000) |
| 88 | |
| 89 | config RUSTC_CLANG_LLVM_COMPATIBLE |
| 90 | bool |
| 91 | default y if CC_IS_CLANG && RUSTC_LLVM_MAJOR_VERSION = $(shell,expr $(cc-version) / 10000) |
| 92 | help |
| 93 | This indicates whether Rust and Clang use LLVM of the same major |
| 94 | version. |
| 95 | |
| 96 | Operations involving handling LLVM IR or bitcode (e.g. cross-language |
| 97 | LTO) require the same LLVM major version to work properly. For best |
| 98 | compatibility it is recommended that the exact same LLVM is used. |
| 99 | |
| 100 | config ARCH_HAS_CC_CAN_LINK |
| 101 | bool |
| 102 | |
| 103 | config CC_CAN_LINK |
| 104 | bool |
| 105 | default ARCH_CC_CAN_LINK if ARCH_HAS_CC_CAN_LINK |
| 106 | default $(cc_can_link_user,$(m64-flag)) if 64BIT |
| 107 | default $(cc_can_link_user,$(m32-flag)) |
| 108 | |
| 109 | # Fixed in GCC 14, 13.3, 12.4 and 11.5 |
| 110 | # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113921 |
| 111 | config GCC_ASM_GOTO_OUTPUT_BROKEN |
| 112 | bool |
| 113 | depends on CC_IS_GCC |
| 114 | default y if GCC_VERSION < 110500 |
| 115 | default y if GCC_VERSION >= 120000 && GCC_VERSION < 120400 |
| 116 | default y if GCC_VERSION >= 130000 && GCC_VERSION < 130300 |
| 117 | |
| 118 | config CC_HAS_ASM_GOTO_OUTPUT |
| 119 | def_bool y |
| 120 | depends on !GCC_ASM_GOTO_OUTPUT_BROKEN |
| 121 | depends on $(success,echo 'int foo(int x) { asm goto ("": "=r"(x) ::: bar); return x; bar: return 0; }' | $(CC) -x c - -c -o /dev/null) |
| 122 | |
| 123 | config CC_HAS_ASM_GOTO_TIED_OUTPUT |
| 124 | depends on CC_HAS_ASM_GOTO_OUTPUT |
| 125 | # Detect buggy gcc and clang, fixed in gcc-11 clang-14. |
| 126 | def_bool $(success,echo 'int foo(int *x) { asm goto (".long (%l[bar]) - .": "+m"(*x) ::: bar); return *x; bar: return 0; }' | $CC -x c - -c -o /dev/null) |
| 127 | |
| 128 | config TOOLS_SUPPORT_RELR |
| 129 | def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh) |
| 130 | |
| 131 | config CC_HAS_ASM_INLINE |
| 132 | def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null) |
| 133 | |
| 134 | config CC_HAS_ASSUME |
| 135 | bool |
| 136 | # clang needs to be at least 19.1.0 since the meaning of the assume |
| 137 | # attribute changed: |
| 138 | # https://github.com/llvm/llvm-project/commit/c44fa3e8a9a44c2e9a575768a3c185354b9f6c17 |
| 139 | default y if CC_IS_CLANG && CLANG_VERSION >= 190100 |
| 140 | # supported since gcc 13.1.0 |
| 141 | # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106654 |
| 142 | default y if CC_IS_GCC && GCC_VERSION >= 130100 |
| 143 | |
| 144 | config CC_HAS_NO_PROFILE_FN_ATTR |
| 145 | def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror) |
| 146 | |
| 147 | config CC_HAS_COUNTED_BY |
| 148 | bool |
| 149 | # clang needs to be at least 20.1.0 to avoid potential crashes |
| 150 | # when building structures that contain __counted_by |
| 151 | # https://github.com/ClangBuiltLinux/linux/issues/2114 |
| 152 | # https://github.com/llvm/llvm-project/commit/160fb1121cdf703c3ef5e61fb26c5659eb581489 |
| 153 | default y if CC_IS_CLANG && CLANG_VERSION >= 200100 |
| 154 | # supported since gcc 15.1.0 |
| 155 | # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896 |
| 156 | default y if CC_IS_GCC && GCC_VERSION >= 150100 |
| 157 | |
| 158 | config CC_HAS_COUNTED_BY_PTR |
| 159 | bool |
| 160 | # supported since clang 22 |
| 161 | default y if CC_IS_CLANG && CLANG_VERSION >= 220100 |
| 162 | # supported since gcc 16.0.0 |
| 163 | default y if CC_IS_GCC && GCC_VERSION >= 160000 |
| 164 | |
| 165 | config CC_HAS_BROKEN_COUNTED_BY_REF |
| 166 | bool |
| 167 | # https://github.com/llvm/llvm-project/issues/182575 |
| 168 | default y if CC_IS_CLANG && CLANG_VERSION < 220100 |
| 169 | |
| 170 | config CC_HAS_ALLOC_TOKEN |
| 171 | def_bool $(cc-option,-falloc-token-max=123) |
| 172 | |
| 173 | config CC_HAS_MULTIDIMENSIONAL_NONSTRING |
| 174 | def_bool $(success,echo 'char tag[][4] __attribute__((__nonstring__)) = { };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror) |
| 175 | |
| 176 | config CC_OPT_INLINE_MEMSET |
| 177 | string |
| 178 | default "-finline-stringops=memset" if $(cc-option,-finline-stringops=memset) |
| 179 | default "-mllvm -max-store-memset=4294967294" if $(cc-option,-mllvm -max-store-memset=4294967294) |
| 180 | |
| 181 | config LD_CAN_USE_KEEP_IN_OVERLAY |
| 182 | # ld.lld prior to 21.0.0 did not support KEEP within an overlay description |
| 183 | # https://github.com/llvm/llvm-project/pull/130661 |
| 184 | def_bool LD_IS_BFD || LLD_VERSION >= 210000 |
| 185 | |
| 186 | config RUSTC_HAS_SPAN_FILE |
| 187 | def_bool RUSTC_VERSION >= 108800 |
| 188 | |
| 189 | config RUSTC_HAS_UNNECESSARY_TRANSMUTES |
| 190 | def_bool RUSTC_VERSION >= 108800 |
| 191 | |
| 192 | config RUSTC_HAS_FILE_WITH_NUL |
| 193 | def_bool RUSTC_VERSION >= 108900 |
| 194 | |
| 195 | config RUSTC_HAS_FILE_AS_C_STR |
| 196 | def_bool RUSTC_VERSION >= 109100 |
| 197 | |
| 198 | config RUSTC_HAS_SUSPICIOUS_RUNTIME_SYMBOL_DEFINITIONS |
| 199 | def_bool RUSTC_VERSION >= 109800 |
| 200 | |
| 201 | config PAHOLE_VERSION |
| 202 | int |
| 203 | default "$(PAHOLE_VERSION)" |
| 204 | |
| 205 | config CONSTRUCTORS |
| 206 | bool |
| 207 | |
| 208 | config IRQ_WORK |
| 209 | def_bool y if SMP |
| 210 | |
| 211 | config BUILDTIME_TABLE_SORT |
| 212 | bool |
| 213 | |
| 214 | config THREAD_INFO_IN_TASK |
| 215 | bool |
| 216 | help |
| 217 | Select this to move thread_info off the stack into task_struct. To |
| 218 | make this work, an arch will need to remove all thread_info fields |
| 219 | except flags and fix any runtime bugs. |
| 220 | |
| 221 | One subtle change that will be needed is to use try_get_task_stack() |
| 222 | and put_task_stack() in save_thread_stack_tsk() and get_wchan(). |
| 223 | |
| 224 | menu "General setup" |
| 225 | |
| 226 | config BROKEN |
| 227 | bool |
| 228 | help |
| 229 | This option allows you to choose whether you want to try to |
| 230 | compile (and fix) old drivers that haven't been updated to |
| 231 | new infrastructure. |
| 232 | |
| 233 | config BROKEN_ON_SMP |
| 234 | bool |
| 235 | depends on BROKEN || !SMP |
| 236 | default y |
| 237 | |
| 238 | config INIT_ENV_ARG_LIMIT |
| 239 | int |
| 240 | default 32 if !UML |
| 241 | default 128 if UML |
| 242 | help |
| 243 | Maximum of each of the number of arguments and environment |
| 244 | variables passed to init from the kernel command line. |
| 245 | |
| 246 | config COMPILE_TEST |
| 247 | bool "Compile also drivers which will not load" |
| 248 | depends on HAS_IOMEM |
| 249 | help |
| 250 | Some drivers can be compiled on a different platform than they are |
| 251 | intended to be run on. Despite they cannot be loaded there (or even |
| 252 | when they load they cannot be used due to missing HW support), |
| 253 | developers still, opposing to distributors, might want to build such |
| 254 | drivers to compile-test them. |
| 255 | |
| 256 | If you are a developer and want to build everything available, say Y |
| 257 | here. If you are a user/distributor, say N here to exclude useless |
| 258 | drivers to be distributed. |
| 259 | |
| 260 | config WERROR |
| 261 | bool "Compile the kernel with warnings as errors" |
| 262 | default COMPILE_TEST |
| 263 | help |
| 264 | A kernel build should not cause any compiler warnings, and this |
| 265 | enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags |
| 266 | to enforce that rule by default. Certain warnings from other tools |
| 267 | such as the linker may be upgraded to errors with this option as |
| 268 | well. |
| 269 | |
| 270 | However, if you have a new (or very old) compiler or linker with odd |
| 271 | and unusual warnings, or you have some architecture with problems, |
| 272 | you may need to disable this config option in order to |
| 273 | successfully build the kernel. |
| 274 | |
| 275 | If in doubt, say Y. |
| 276 | |
| 277 | config UAPI_HEADER_TEST |
| 278 | bool "Compile test UAPI headers" |
| 279 | depends on HEADERS_INSTALL |
| 280 | help |
| 281 | Compile test headers exported to user-space to ensure they are |
| 282 | self-contained, i.e. compilable as standalone units. |
| 283 | |
| 284 | If you are a developer or tester and want to ensure the exported |
| 285 | headers are self-contained, say Y here. Otherwise, choose N. |
| 286 | |
| 287 | config LOCALVERSION |
| 288 | string "Local version - append to kernel release" |
| 289 | help |
| 290 | Append an extra string to the end of your kernel version. |
| 291 | This will show up when you type uname, for example. |
| 292 | The string you set here will be appended after the contents of |
| 293 | any files with a filename matching localversion* in your |
| 294 | object and source tree, in that order. Your total string can |
| 295 | be a maximum of 64 characters. |
| 296 | |
| 297 | config LOCALVERSION_AUTO |
| 298 | bool "Automatically append version information to the version string" |
| 299 | default y |
| 300 | depends on !COMPILE_TEST |
| 301 | help |
| 302 | This will try to automatically determine if the current tree is a |
| 303 | release tree by looking for git tags that belong to the current |
| 304 | top of tree revision. |
| 305 | |
| 306 | A string of the format -gxxxxxxxx will be added to the localversion |
| 307 | if a git-based tree is found. The string generated by this will be |
| 308 | appended after any matching localversion* files, and after the value |
| 309 | set in CONFIG_LOCALVERSION. |
| 310 | |
| 311 | (The actual string used here is the first 12 characters produced |
| 312 | by running the command: |
| 313 | |
| 314 | $ git rev-parse --verify HEAD |
| 315 | |
| 316 | which is done within the script "scripts/setlocalversion".) |
| 317 | |
| 318 | config BUILD_SALT |
| 319 | string "Build ID Salt" |
| 320 | default "" |
| 321 | help |
| 322 | The build ID is used to link binaries and their debug info. Setting |
| 323 | this option will use the value in the calculation of the build id. |
| 324 | This is mostly useful for distributions which want to ensure the |
| 325 | build is unique between builds. It's safe to leave the default. |
| 326 | |
| 327 | config HAVE_KERNEL_GZIP |
| 328 | bool |
| 329 | |
| 330 | config HAVE_KERNEL_BZIP2 |
| 331 | bool |
| 332 | |
| 333 | config HAVE_KERNEL_LZMA |
| 334 | bool |
| 335 | |
| 336 | config HAVE_KERNEL_XZ |
| 337 | bool |
| 338 | |
| 339 | config HAVE_KERNEL_LZO |
| 340 | bool |
| 341 | |
| 342 | config HAVE_KERNEL_LZ4 |
| 343 | bool |
| 344 | |
| 345 | config HAVE_KERNEL_ZSTD |
| 346 | bool |
| 347 | |
| 348 | config HAVE_KERNEL_UNCOMPRESSED |
| 349 | bool |
| 350 | |
| 351 | choice |
| 352 | prompt "Kernel compression mode" |
| 353 | default KERNEL_GZIP |
| 354 | depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 || HAVE_KERNEL_ZSTD || HAVE_KERNEL_UNCOMPRESSED |
| 355 | help |
| 356 | The linux kernel is a kind of self-extracting executable. |
| 357 | Several compression algorithms are available, which differ |
| 358 | in efficiency, compression and decompression speed. |
| 359 | Compression speed is only relevant when building a kernel. |
| 360 | Decompression speed is relevant at each boot. |
| 361 | |
| 362 | If you have any problems with bzip2 or lzma compressed |
| 363 | kernels, mail me (Alain Knaff) <[email protected]>. (An older |
| 364 | version of this functionality (bzip2 only), for 2.4, was |
| 365 | supplied by Christian Ludwig) |
| 366 | |
| 367 | High compression options are mostly useful for users, who |
| 368 | are low on disk space (embedded systems), but for whom ram |
| 369 | size matters less. |
| 370 | |
| 371 | If in doubt, select 'gzip' |
| 372 | |
| 373 | config KERNEL_GZIP |
| 374 | bool "Gzip" |
| 375 | depends on HAVE_KERNEL_GZIP |
| 376 | help |
| 377 | The old and tried gzip compression. It provides a good balance |
| 378 | between compression ratio and decompression speed. |
| 379 | |
| 380 | config KERNEL_BZIP2 |
| 381 | bool "Bzip2" |
| 382 | depends on HAVE_KERNEL_BZIP2 |
| 383 | help |
| 384 | Its compression ratio and speed is intermediate. |
| 385 | Decompression speed is slowest among the choices. The kernel |
| 386 | size is about 10% smaller with bzip2, in comparison to gzip. |
| 387 | Bzip2 uses a large amount of memory. For modern kernels you |
| 388 | will need at least 8MB RAM or more for booting. |
| 389 | |
| 390 | config KERNEL_LZMA |
| 391 | bool "LZMA" |
| 392 | depends on HAVE_KERNEL_LZMA |
| 393 | help |
| 394 | This compression algorithm's ratio is best. Decompression speed |
| 395 | is between gzip and bzip2. Compression is slowest. |
| 396 | The kernel size is about 33% smaller with LZMA in comparison to gzip. |
| 397 | |
| 398 | config KERNEL_XZ |
| 399 | bool "XZ" |
| 400 | depends on HAVE_KERNEL_XZ |
| 401 | help |
| 402 | XZ uses the LZMA2 algorithm and instruction set specific |
| 403 | BCJ filters which can improve compression ratio of executable |
| 404 | code. The size of the kernel is about 30% smaller with XZ in |
| 405 | comparison to gzip. On architectures for which there is a BCJ |
| 406 | filter (i386, x86_64, ARM, ARM64, RISC-V, big endian PowerPC, |
| 407 | and SPARC), XZ will create a few percent smaller kernel than |
| 408 | plain LZMA. |
| 409 | |
| 410 | The speed is about the same as with LZMA: The decompression |
| 411 | speed of XZ is better than that of bzip2 but worse than gzip |
| 412 | and LZO. Compression is slow. |
| 413 | |
| 414 | config KERNEL_LZO |
| 415 | bool "LZO" |
| 416 | depends on HAVE_KERNEL_LZO |
| 417 | help |
| 418 | Its compression ratio is the poorest among the choices. The kernel |
| 419 | size is about 10% bigger than gzip; however its speed |
| 420 | (both compression and decompression) is the fastest. |
| 421 | |
| 422 | config KERNEL_LZ4 |
| 423 | bool "LZ4" |
| 424 | depends on HAVE_KERNEL_LZ4 |
| 425 | help |
| 426 | LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. |
| 427 | A preliminary version of LZ4 de/compression tool is available at |
| 428 | <https://code.google.com/p/lz4/>. |
| 429 | |
| 430 | Its compression ratio is worse than LZO. The size of the kernel |
| 431 | is about 8% bigger than LZO. But the decompression speed is |
| 432 | faster than LZO. |
| 433 | |
| 434 | config KERNEL_ZSTD |
| 435 | bool "ZSTD" |
| 436 | depends on HAVE_KERNEL_ZSTD |
| 437 | help |
| 438 | ZSTD is a compression algorithm targeting intermediate compression |
| 439 | with fast decompression speed. It will compress better than GZIP and |
| 440 | decompress around the same speed as LZO, but slower than LZ4. You |
| 441 | will need at least 192 KB RAM or more for booting. The zstd command |
| 442 | line tool is required for compression. |
| 443 | |
| 444 | config KERNEL_UNCOMPRESSED |
| 445 | bool "None" |
| 446 | depends on HAVE_KERNEL_UNCOMPRESSED |
| 447 | help |
| 448 | Produce uncompressed kernel image. This option is usually not what |
| 449 | you want. It is useful for debugging the kernel in slow simulation |
| 450 | environments, where decompressing and moving the kernel is awfully |
| 451 | slow. This option allows early boot code to skip the decompressor |
| 452 | and jump right at uncompressed kernel image. |
| 453 | |
| 454 | endchoice |
| 455 | |
| 456 | config DEFAULT_INIT |
| 457 | string "Default init path" |
| 458 | default "" |
| 459 | help |
| 460 | This option determines the default init for the system if no init= |
| 461 | option is passed on the kernel command line. If the requested path is |
| 462 | not present, we will still then move on to attempting further |
| 463 | locations (e.g. /sbin/init, etc). If this is empty, we will just use |
| 464 | the fallback list when init= is not passed. |
| 465 | |
| 466 | config DEFAULT_HOSTNAME |
| 467 | string "Default hostname" |
| 468 | default "(none)" |
| 469 | help |
| 470 | This option determines the default system hostname before userspace |
| 471 | calls sethostname(2). The kernel traditionally uses "(none)" here, |
| 472 | but you may wish to use a different default here to make a minimal |
| 473 | system more usable with less configuration. |
| 474 | |
| 475 | config SYSVIPC |
| 476 | bool "System V IPC" |
| 477 | help |
| 478 | Inter Process Communication is a suite of library functions and |
| 479 | system calls which let processes (running programs) synchronize and |
| 480 | exchange information. It is generally considered to be a good thing, |
| 481 | and some programs won't run unless you say Y here. In particular, if |
| 482 | you want to run the DOS emulator dosemu under Linux (read the |
| 483 | DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), |
| 484 | you'll need to say Y here. |
| 485 | |
| 486 | You can find documentation about IPC with "info ipc" and also in |
| 487 | section 6.4 of the Linux Programmer's Guide, available from |
| 488 | <http://www.tldp.org/guides.html>. |
| 489 | |
| 490 | config SYSVIPC_SYSCTL |
| 491 | bool |
| 492 | depends on SYSVIPC |
| 493 | depends on SYSCTL |
| 494 | default y |
| 495 | |
| 496 | config SYSVIPC_COMPAT |
| 497 | def_bool y |
| 498 | depends on COMPAT && SYSVIPC |
| 499 | |
| 500 | config POSIX_MQUEUE |
| 501 | bool "POSIX Message Queues" |
| 502 | depends on NET |
| 503 | help |
| 504 | POSIX variant of message queues is a part of IPC. In POSIX message |
| 505 | queues every message has a priority which decides about succession |
| 506 | of receiving it by a process. If you want to compile and run |
| 507 | programs written e.g. for Solaris with use of its POSIX message |
| 508 | queues (functions mq_*) say Y here. |
| 509 | |
| 510 | POSIX message queues are visible as a filesystem called 'mqueue' |
| 511 | and can be mounted somewhere if you want to do filesystem |
| 512 | operations on message queues. |
| 513 | |
| 514 | If unsure, say Y. |
| 515 | |
| 516 | config POSIX_MQUEUE_SYSCTL |
| 517 | bool |
| 518 | depends on POSIX_MQUEUE |
| 519 | depends on SYSCTL |
| 520 | default y |
| 521 | |
| 522 | config WATCH_QUEUE |
| 523 | bool "General notification queue" |
| 524 | default n |
| 525 | help |
| 526 | |
| 527 | This is a general notification queue for the kernel to pass events to |
| 528 | userspace by splicing them into pipes. It can be used in conjunction |
| 529 | with watches for key/keyring change notifications and device |
| 530 | notifications. |
| 531 | |
| 532 | See Documentation/core-api/watch_queue.rst |
| 533 | |
| 534 | config CROSS_MEMORY_ATTACH |
| 535 | bool "Enable process_vm_readv/writev syscalls" |
| 536 | depends on MMU |
| 537 | default y |
| 538 | help |
| 539 | Enabling this option adds the system calls process_vm_readv and |
| 540 | process_vm_writev which allow a process with the correct privileges |
| 541 | to directly read from or write to another process' address space. |
| 542 | See the man page for more details. |
| 543 | |
| 544 | config AUDIT |
| 545 | bool "Auditing support" |
| 546 | depends on NET |
| 547 | help |
| 548 | Enable auditing infrastructure that can be used with another |
| 549 | kernel subsystem, such as SELinux (which requires this for |
| 550 | logging of avc messages output). System call auditing is included |
| 551 | on architectures which support it. |
| 552 | |
| 553 | config HAVE_ARCH_AUDITSYSCALL |
| 554 | bool |
| 555 | |
| 556 | config AUDITSYSCALL |
| 557 | def_bool y |
| 558 | depends on AUDIT && HAVE_ARCH_AUDITSYSCALL |
| 559 | select FSNOTIFY |
| 560 | |
| 561 | source "kernel/irq/Kconfig" |
| 562 | source "kernel/time/Kconfig" |
| 563 | source "kernel/bpf/Kconfig" |
| 564 | source "kernel/Kconfig.preempt" |
| 565 | |
| 566 | menu "CPU/Task time and stats accounting" |
| 567 | |
| 568 | config VIRT_CPU_ACCOUNTING |
| 569 | bool |
| 570 | |
| 571 | choice |
| 572 | prompt "Cputime accounting" |
| 573 | default VIRT_CPU_ACCOUNTING_GEN if NO_HZ_FULL |
| 574 | default TICK_CPU_ACCOUNTING |
| 575 | |
| 576 | # Kind of a stub config for the pure tick based cputime accounting |
| 577 | config TICK_CPU_ACCOUNTING |
| 578 | bool "Simple tick based cputime accounting" |
| 579 | depends on !S390 && !NO_HZ_FULL |
| 580 | help |
| 581 | This is the basic tick based cputime accounting that maintains |
| 582 | statistics about user, system and idle time spent on per jiffies |
| 583 | granularity. |
| 584 | |
| 585 | If unsure, say Y. |
| 586 | |
| 587 | config VIRT_CPU_ACCOUNTING_NATIVE |
| 588 | bool "Deterministic task and CPU time accounting" |
| 589 | depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL |
| 590 | select VIRT_CPU_ACCOUNTING |
| 591 | help |
| 592 | Select this option to enable more accurate task and CPU time |
| 593 | accounting. This is done by reading a CPU counter on each |
| 594 | kernel entry and exit and on transitions within the kernel |
| 595 | between system, softirq and hardirq state, so there is a |
| 596 | small performance impact. In the case of s390 or IBM POWER > 5, |
| 597 | this also enables accounting of stolen time on logically-partitioned |
| 598 | systems. |
| 599 | |
| 600 | config VIRT_CPU_ACCOUNTING_GEN |
| 601 | bool "Full dynticks CPU time accounting" |
| 602 | depends on HAVE_CONTEXT_TRACKING_USER |
| 603 | depends on HAVE_VIRT_CPU_ACCOUNTING_GEN |
| 604 | depends on GENERIC_CLOCKEVENTS |
| 605 | select VIRT_CPU_ACCOUNTING |
| 606 | select CONTEXT_TRACKING_USER |
| 607 | help |
| 608 | Select this option to enable task and CPU time accounting on full |
| 609 | dynticks systems. This accounting is implemented by watching every |
| 610 | kernel-user boundaries using the context tracking subsystem. |
| 611 | The accounting is thus performed at the expense of some significant |
| 612 | overhead. |
| 613 | |
| 614 | For now this is only useful if you are working on the full |
| 615 | dynticks subsystem development. |
| 616 | |
| 617 | If unsure, say N. |
| 618 | |
| 619 | endchoice |
| 620 | |
| 621 | config IRQ_TIME_ACCOUNTING |
| 622 | bool "Fine granularity task level IRQ time accounting" |
| 623 | depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE |
| 624 | help |
| 625 | Select this option to enable fine granularity task irq time |
| 626 | accounting. This is done by reading a timestamp on each |
| 627 | transitions between softirq and hardirq state, so there can be a |
| 628 | small performance impact. |
| 629 | |
| 630 | If in doubt, say N here. |
| 631 | |
| 632 | config HAVE_SCHED_AVG_IRQ |
| 633 | def_bool y |
| 634 | depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING |
| 635 | depends on SMP |
| 636 | |
| 637 | config SCHED_HW_PRESSURE |
| 638 | bool |
| 639 | default y if ARM && ARM_CPU_TOPOLOGY |
| 640 | default y if ARM64 |
| 641 | depends on SMP |
| 642 | depends on CPU_FREQ_THERMAL |
| 643 | help |
| 644 | Select this option to enable HW pressure accounting in the |
| 645 | scheduler. HW pressure is the value conveyed to the scheduler |
| 646 | that reflects the reduction in CPU compute capacity resulted from |
| 647 | HW throttling. HW throttling occurs when the performance of |
| 648 | a CPU is capped due to high operating temperatures as an example. |
| 649 | |
| 650 | If selected, the scheduler will be able to balance tasks accordingly, |
| 651 | i.e. put less load on throttled CPUs than on non/less throttled ones. |
| 652 | |
| 653 | This requires the architecture to implement |
| 654 | arch_update_hw_pressure() and arch_scale_thermal_pressure(). |
| 655 | |
| 656 | config BSD_PROCESS_ACCT |
| 657 | bool "BSD Process Accounting (DEPRECATED)" |
| 658 | depends on MULTIUSER |
| 659 | default n |
| 660 | help |
| 661 | If you say Y here, a user level program will be able to instruct the |
| 662 | kernel (via a special system call) to write process accounting |
| 663 | information to a file: whenever a process exits, information about |
| 664 | that process will be appended to the file by the kernel. The |
| 665 | information includes things such as creation time, owning user, |
| 666 | command name, memory usage, controlling terminal etc. (the complete |
| 667 | list is in the struct acct in <file:include/linux/acct.h>). It is |
| 668 | up to the user level program to do useful things with this |
| 669 | information. This mechanism is antiquated and has significant |
| 670 | scalability issues. You probably want to use eBPF instead. Say |
| 671 | N unless you really need this. |
| 672 | |
| 673 | config BSD_PROCESS_ACCT_V3 |
| 674 | bool "BSD Process Accounting version 3 file format" |
| 675 | depends on BSD_PROCESS_ACCT |
| 676 | default n |
| 677 | help |
| 678 | If you say Y here, the process accounting information is written |
| 679 | in a new file format that also logs the process IDs of each |
| 680 | process and its parent. Note that this file format is incompatible |
| 681 | with previous v0/v1/v2 file formats, so you will need updated tools |
| 682 | for processing it. A preliminary version of these tools is available |
| 683 | at <http://www.gnu.org/software/acct/>. |
| 684 | |
| 685 | config TASKSTATS |
| 686 | bool "Export task/process statistics through netlink" |
| 687 | depends on NET |
| 688 | depends on MULTIUSER |
| 689 | default n |
| 690 | help |
| 691 | Export selected statistics for tasks/processes through the |
| 692 | generic netlink interface. Unlike BSD process accounting, the |
| 693 | statistics are available during the lifetime of tasks/processes as |
| 694 | responses to commands. Like BSD accounting, they are sent to user |
| 695 | space on task exit. |
| 696 | |
| 697 | Say N if unsure. |
| 698 | |
| 699 | config TASK_DELAY_ACCT |
| 700 | bool "Enable per-task delay accounting" |
| 701 | depends on TASKSTATS |
| 702 | select SCHED_INFO |
| 703 | help |
| 704 | Collect information on time spent by a task waiting for system |
| 705 | resources like cpu, synchronous block I/O completion and swapping |
| 706 | in pages. Such statistics can help in setting a task's priorities |
| 707 | relative to other tasks for cpu, io, rss limits etc. |
| 708 | |
| 709 | Say N if unsure. |
| 710 | |
| 711 | config TASK_XACCT |
| 712 | bool "Enable extended accounting over taskstats" |
| 713 | depends on TASKSTATS |
| 714 | help |
| 715 | Collect extended task accounting data and send the data |
| 716 | to userland for processing over the taskstats interface. |
| 717 | |
| 718 | Say N if unsure. |
| 719 | |
| 720 | config TASK_IO_ACCOUNTING |
| 721 | bool "Enable per-task storage I/O accounting" |
| 722 | depends on TASK_XACCT |
| 723 | help |
| 724 | Collect information on the number of bytes of storage I/O which this |
| 725 | task has caused. |
| 726 | |
| 727 | Say N if unsure. |
| 728 | |
| 729 | config PSI |
| 730 | bool "Pressure stall information tracking" |
| 731 | select KERNFS |
| 732 | help |
| 733 | Collect metrics that indicate how overcommitted the CPU, memory, |
| 734 | and IO capacity are in the system. |
| 735 | |
| 736 | If you say Y here, the kernel will create /proc/pressure/ with the |
| 737 | pressure statistics files cpu, memory, and io. These will indicate |
| 738 | the share of walltime in which some or all tasks in the system are |
| 739 | delayed due to contention of the respective resource. |
| 740 | |
| 741 | In kernels with cgroup support, cgroups (cgroup2 only) will |
| 742 | have cpu.pressure, memory.pressure, and io.pressure files, |
| 743 | which aggregate pressure stalls for the grouped tasks only. |
| 744 | |
| 745 | For more details see Documentation/accounting/psi.rst. |
| 746 | |
| 747 | Say N if unsure. |
| 748 | |
| 749 | config PSI_DEFAULT_DISABLED |
| 750 | bool "Require boot parameter to enable pressure stall information tracking" |
| 751 | default n |
| 752 | depends on PSI |
| 753 | help |
| 754 | If set, pressure stall information tracking will be disabled |
| 755 | per default but can be enabled through passing psi=1 on the |
| 756 | kernel commandline during boot. |
| 757 | |
| 758 | This feature adds some code to the task wakeup and sleep |
| 759 | paths of the scheduler. The overhead is too low to affect |
| 760 | common scheduling-intense workloads in practice (such as |
| 761 | webservers, memcache), but it does show up in artificial |
| 762 | scheduler stress tests, such as hackbench. |
| 763 | |
| 764 | If you are paranoid and not sure what the kernel will be |
| 765 | used for, say Y. |
| 766 | |
| 767 | Say N if unsure. |
| 768 | |
| 769 | endmenu # "CPU/Task time and stats accounting" |
| 770 | |
| 771 | config CPU_ISOLATION |
| 772 | bool "CPU isolation" |
| 773 | depends on SMP |
| 774 | default y |
| 775 | help |
| 776 | Make sure that CPUs running critical tasks are not disturbed by |
| 777 | any source of "noise" such as unbound workqueues, timers, kthreads... |
| 778 | Unbound jobs get offloaded to housekeeping CPUs. This is driven by |
| 779 | the "isolcpus=" boot parameter. |
| 780 | |
| 781 | Say Y if unsure. |
| 782 | |
| 783 | source "kernel/rcu/Kconfig" |
| 784 | |
| 785 | config IKCONFIG |
| 786 | tristate "Kernel .config support" |
| 787 | help |
| 788 | This option enables the complete Linux kernel ".config" file |
| 789 | contents to be saved in the kernel. It provides documentation |
| 790 | of which kernel options are used in a running kernel or in an |
| 791 | on-disk kernel. This information can be extracted from the kernel |
| 792 | image file with the script scripts/extract-ikconfig and used as |
| 793 | input to rebuild the current kernel or to build another kernel. |
| 794 | It can also be extracted from a running kernel by reading |
| 795 | /proc/config.gz if enabled (below). |
| 796 | |
| 797 | config IKCONFIG_PROC |
| 798 | bool "Enable access to .config through /proc/config.gz" |
| 799 | depends on IKCONFIG && PROC_FS |
| 800 | help |
| 801 | This option enables access to the kernel configuration file |
| 802 | through /proc/config.gz. |
| 803 | |
| 804 | config IKHEADERS |
| 805 | tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz" |
| 806 | depends on SYSFS |
| 807 | help |
| 808 | This option enables access to the in-kernel headers that are generated during |
| 809 | the build process. These can be used to build eBPF tracing programs, |
| 810 | or similar programs. If you build the headers as a module, a module called |
| 811 | kheaders.ko is built which can be loaded on-demand to get access to headers. |
| 812 | |
| 813 | config LOG_BUF_SHIFT |
| 814 | int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" |
| 815 | range 12 25 |
| 816 | default 17 |
| 817 | depends on PRINTK |
| 818 | help |
| 819 | Select the minimal kernel log buffer size as a power of 2. |
| 820 | The final size is affected by LOG_CPU_MAX_BUF_SHIFT config |
| 821 | parameter, see below. Any higher size also might be forced |
| 822 | by "log_buf_len" boot parameter. |
| 823 | |
| 824 | Examples: |
| 825 | 17 => 128 KB |
| 826 | 16 => 64 KB |
| 827 | 15 => 32 KB |
| 828 | 14 => 16 KB |
| 829 | 13 => 8 KB |
| 830 | 12 => 4 KB |
| 831 | |
| 832 | config LOG_CPU_MAX_BUF_SHIFT |
| 833 | int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" |
| 834 | depends on SMP |
| 835 | range 0 21 |
| 836 | default 0 if BASE_SMALL |
| 837 | default 12 |
| 838 | depends on PRINTK |
| 839 | help |
| 840 | This option allows to increase the default ring buffer size |
| 841 | according to the number of CPUs. The value defines the contribution |
| 842 | of each CPU as a power of 2. The used space is typically only few |
| 843 | lines however it might be much more when problems are reported, |
| 844 | e.g. backtraces. |
| 845 | |
| 846 | The increased size means that a new buffer has to be allocated and |
| 847 | the original static one is unused. It makes sense only on systems |
| 848 | with more CPUs. Therefore this value is used only when the sum of |
| 849 | contributions is greater than the half of the default kernel ring |
| 850 | buffer as defined by LOG_BUF_SHIFT. The default values are set |
| 851 | so that more than 16 CPUs are needed to trigger the allocation. |
| 852 | |
| 853 | Also this option is ignored when "log_buf_len" kernel parameter is |
| 854 | used as it forces an exact (power of two) size of the ring buffer. |
| 855 | |
| 856 | The number of possible CPUs is used for this computation ignoring |
| 857 | hotplugging making the computation optimal for the worst case |
| 858 | scenario while allowing a simple algorithm to be used from bootup. |
| 859 | |
| 860 | Examples shift values and their meaning: |
| 861 | 17 => 128 KB for each CPU |
| 862 | 16 => 64 KB for each CPU |
| 863 | 15 => 32 KB for each CPU |
| 864 | 14 => 16 KB for each CPU |
| 865 | 13 => 8 KB for each CPU |
| 866 | 12 => 4 KB for each CPU |
| 867 | |
| 868 | config PRINTK_INDEX |
| 869 | bool "Printk indexing debugfs interface" |
| 870 | depends on PRINTK && DEBUG_FS |
| 871 | help |
| 872 | Add support for indexing of all printk formats known at compile time |
| 873 | at <debugfs>/printk/index/<module>. |
| 874 | |
| 875 | This can be used as part of maintaining daemons which monitor |
| 876 | /dev/kmsg, as it permits auditing the printk formats present in a |
| 877 | kernel, allowing detection of cases where monitored printks are |
| 878 | changed or no longer present. |
| 879 | |
| 880 | There is no additional runtime cost to printk with this enabled. |
| 881 | |
| 882 | # |
| 883 | # Architectures with an unreliable sched_clock() should select this: |
| 884 | # |
| 885 | config HAVE_UNSTABLE_SCHED_CLOCK |
| 886 | bool |
| 887 | |
| 888 | config GENERIC_SCHED_CLOCK |
| 889 | bool |
| 890 | |
| 891 | menu "Scheduler features" |
| 892 | |
| 893 | config UCLAMP_TASK |
| 894 | bool "Enable utilization clamping for RT/FAIR tasks" |
| 895 | depends on CPU_FREQ_GOV_SCHEDUTIL |
| 896 | help |
| 897 | This feature enables the scheduler to track the clamped utilization |
| 898 | of each CPU based on RUNNABLE tasks scheduled on that CPU. |
| 899 | |
| 900 | With this option, the user can specify the min and max CPU |
| 901 | utilization allowed for RUNNABLE tasks. The max utilization defines |
| 902 | the maximum frequency a task should use while the min utilization |
| 903 | defines the minimum frequency it should use. |
| 904 | |
| 905 | Both min and max utilization clamp values are hints to the scheduler, |
| 906 | aiming at improving its frequency selection policy, but they do not |
| 907 | enforce or grant any specific bandwidth for tasks. |
| 908 | |
| 909 | If in doubt, say N. |
| 910 | |
| 911 | config UCLAMP_BUCKETS_COUNT |
| 912 | int "Number of supported utilization clamp buckets" |
| 913 | range 5 20 |
| 914 | default 5 |
| 915 | depends on UCLAMP_TASK |
| 916 | help |
| 917 | Defines the number of clamp buckets to use. The range of each bucket |
| 918 | will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the |
| 919 | number of clamp buckets the finer their granularity and the higher |
| 920 | the precision of clamping aggregation and tracking at run-time. |
| 921 | |
| 922 | For example, with the minimum configuration value we will have 5 |
| 923 | clamp buckets tracking 20% utilization each. A 25% boosted tasks will |
| 924 | be refcounted in the [20..39]% bucket and will set the bucket clamp |
| 925 | effective value to 25%. |
| 926 | If a second 30% boosted task should be co-scheduled on the same CPU, |
| 927 | that task will be refcounted in the same bucket of the first task and |
| 928 | it will boost the bucket clamp effective value to 30%. |
| 929 | The clamp effective value of a bucket is reset to its nominal value |
| 930 | (20% in the example above) when there are no more tasks refcounted in |
| 931 | that bucket. |
| 932 | |
| 933 | An additional boost/capping margin can be added to some tasks. In the |
| 934 | example above the 25% task will be boosted to 30% until it exits the |
| 935 | CPU. If that should be considered not acceptable on certain systems, |
| 936 | it's always possible to reduce the margin by increasing the number of |
| 937 | clamp buckets to trade off used memory for run-time tracking |
| 938 | precision. |
| 939 | |
| 940 | If in doubt, use the default value. |
| 941 | |
| 942 | config SCHED_PROXY_EXEC |
| 943 | bool "Proxy Execution" |
| 944 | # Avoid some build failures w/ PREEMPT_RT until it can be fixed |
| 945 | depends on !PREEMPT_RT |
| 946 | # Need to investigate how to inform sched_ext of split contexts |
| 947 | depends on !SCHED_CLASS_EXT |
| 948 | # Not particularly useful until we get to multi-rq proxying |
| 949 | depends on EXPERT |
| 950 | help |
| 951 | This option enables proxy execution, a mechanism for mutex-owning |
| 952 | tasks to inherit the scheduling context of higher priority waiters. |
| 953 | |
| 954 | endmenu |
| 955 | |
| 956 | # |
| 957 | # For architectures that support present-but-inaccessible (PROT_NONE) page |
| 958 | # table entries detectable via pte_protnone() / pmd_protnone(): |
| 959 | # |
| 960 | config ARCH_HAS_PTE_PROTNONE |
| 961 | bool |
| 962 | |
| 963 | # |
| 964 | # For architectures that want to enable the support for NUMA-affine scheduler |
| 965 | # balancing logic: |
| 966 | # |
| 967 | config ARCH_SUPPORTS_NUMA_BALANCING |
| 968 | bool |
| 969 | |
| 970 | # |
| 971 | # For architectures that prefer to flush all TLBs after a number of pages |
| 972 | # are unmapped instead of sending one IPI per page to flush. The architecture |
| 973 | # must provide guarantees on what happens if a clean TLB cache entry is |
| 974 | # written after the unmap. Details are in mm/rmap.c near the check for |
| 975 | # should_defer_flush. The architecture should also consider if the full flush |
| 976 | # and the refill costs are offset by the savings of sending fewer IPIs. |
| 977 | config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH |
| 978 | bool |
| 979 | |
| 980 | config CC_HAS_INT128 |
| 981 | def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT |
| 982 | |
| 983 | config CC_IMPLICIT_FALLTHROUGH |
| 984 | string |
| 985 | default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) |
| 986 | default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) |
| 987 | |
| 988 | config CC_MS_EXTENSIONS |
| 989 | string |
| 990 | default "-fms-anonymous-structs" if $(cc-option,-fms-anonymous-structs) |
| 991 | default "-fms-extensions" |
| 992 | |
| 993 | # Currently, disable gcc-10+ array-bounds globally. |
| 994 | # It's still broken in gcc-13, so no upper bound yet. |
| 995 | config GCC10_NO_ARRAY_BOUNDS |
| 996 | def_bool y |
| 997 | |
| 998 | config CC_NO_ARRAY_BOUNDS |
| 999 | bool |
| 1000 | default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC10_NO_ARRAY_BOUNDS |
| 1001 | |
| 1002 | # Currently, disable -Wstringop-overflow for GCC globally. |
| 1003 | config GCC_NO_STRINGOP_OVERFLOW |
| 1004 | def_bool y |
| 1005 | |
| 1006 | config CC_NO_STRINGOP_OVERFLOW |
| 1007 | bool |
| 1008 | default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW |
| 1009 | |
| 1010 | config CC_STRINGOP_OVERFLOW |
| 1011 | bool |
| 1012 | default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW |
| 1013 | |
| 1014 | # |
| 1015 | # For architectures that know their GCC __int128 support is sound |
| 1016 | # |
| 1017 | config ARCH_SUPPORTS_INT128 |
| 1018 | bool |
| 1019 | |
| 1020 | # For architectures that (ab)use NUMA to represent different memory regions |
| 1021 | # all cpu-local but of different latencies, such as SuperH. |
| 1022 | # |
| 1023 | config ARCH_WANT_NUMA_VARIABLE_LOCALITY |
| 1024 | bool |
| 1025 | |
| 1026 | config NUMA_BALANCING |
| 1027 | bool "Memory placement aware NUMA scheduler" |
| 1028 | depends on ARCH_SUPPORTS_NUMA_BALANCING |
| 1029 | depends on ARCH_HAS_PTE_PROTNONE |
| 1030 | depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY |
| 1031 | depends on SMP && NUMA_MIGRATION && !PREEMPT_RT |
| 1032 | help |
| 1033 | This option adds support for automatic NUMA aware memory/task placement. |
| 1034 | The mechanism is quite primitive and is based on migrating memory when |
| 1035 | it has references to the node the task is running on. |
| 1036 | |
| 1037 | This system will be inactive on UMA systems. |
| 1038 | |
| 1039 | config SCHED_CACHE |
| 1040 | bool "Cache aware load balance" |
| 1041 | default y |
| 1042 | depends on SMP |
| 1043 | help |
| 1044 | When enabled, the scheduler will attempt to aggregate tasks from |
| 1045 | the same process onto a single Last Level Cache (LLC) domain when |
| 1046 | possible. This improves cache locality by keeping tasks that share |
| 1047 | resources within the same cache domain, reducing cache misses and |
| 1048 | lowering data access latency. |
| 1049 | |
| 1050 | config NUMA_BALANCING_DEFAULT_ENABLED |
| 1051 | bool "Automatically enable NUMA aware memory/task placement" |
| 1052 | default y |
| 1053 | depends on NUMA_BALANCING |
| 1054 | help |
| 1055 | If set, automatic NUMA balancing will be enabled if running on a NUMA |
| 1056 | machine. |
| 1057 | |
| 1058 | config SLAB_OBJ_EXT |
| 1059 | bool |
| 1060 | |
| 1061 | menuconfig CGROUPS |
| 1062 | bool "Control Group support" |
| 1063 | select KERNFS |
| 1064 | help |
| 1065 | This option adds support for grouping sets of processes together, for |
| 1066 | use with process control subsystems such as Cpusets, CFS, memory |
| 1067 | controls or device isolation. |
| 1068 | See |
| 1069 | - Documentation/scheduler/sched-design-CFS.rst (CFS) |
| 1070 | - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation |
| 1071 | and resource control) |
| 1072 | |
| 1073 | Say N if unsure. |
| 1074 | |
| 1075 | if CGROUPS |
| 1076 | |
| 1077 | config PAGE_COUNTER |
| 1078 | bool |
| 1079 | |
| 1080 | config CGROUP_FAVOR_DYNMODS |
| 1081 | bool "Favor dynamic modification latency reduction by default" |
| 1082 | help |
| 1083 | This option enables the "favordynmods" mount option by default |
| 1084 | which reduces the latencies of dynamic cgroup modifications such |
| 1085 | as task migrations and controller on/offs at the cost of making |
| 1086 | hot path operations such as forks and exits more expensive. |
| 1087 | |
| 1088 | Say N if unsure. |
| 1089 | |
| 1090 | config MEMCG |
| 1091 | bool "Memory controller" |
| 1092 | select PAGE_COUNTER |
| 1093 | select EVENTFD |
| 1094 | select SLAB_OBJ_EXT |
| 1095 | select VM_EVENT_COUNTERS |
| 1096 | help |
| 1097 | Provides control over the memory footprint of tasks in a cgroup. |
| 1098 | |
| 1099 | config MEMCG_NMI_UNSAFE |
| 1100 | bool |
| 1101 | depends on MEMCG |
| 1102 | depends on HAVE_NMI |
| 1103 | depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && !ARCH_HAVE_NMI_SAFE_CMPXCHG |
| 1104 | default y |
| 1105 | |
| 1106 | config MEMCG_NMI_SAFETY_REQUIRES_ATOMIC |
| 1107 | bool |
| 1108 | depends on MEMCG |
| 1109 | depends on HAVE_NMI |
| 1110 | depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && ARCH_HAVE_NMI_SAFE_CMPXCHG |
| 1111 | default y |
| 1112 | |
| 1113 | config MEMCG_V1 |
| 1114 | bool "Legacy cgroup v1 memory controller" |
| 1115 | depends on MEMCG |
| 1116 | default n |
| 1117 | help |
| 1118 | Legacy cgroup v1 memory controller which has been deprecated by |
| 1119 | cgroup v2 implementation. The v1 is there for legacy applications |
| 1120 | which haven't migrated to the new cgroup v2 interface yet. If you |
| 1121 | do not have any such application then you are completely fine leaving |
| 1122 | this option disabled. |
| 1123 | |
| 1124 | Please note that feature set of the legacy memory controller is likely |
| 1125 | going to shrink due to deprecation process. New deployments with v1 |
| 1126 | controller are highly discouraged. |
| 1127 | |
| 1128 | Say N if unsure. |
| 1129 | |
| 1130 | config BLK_CGROUP |
| 1131 | bool "IO controller" |
| 1132 | depends on BLOCK |
| 1133 | default n |
| 1134 | help |
| 1135 | Generic block IO controller cgroup interface. This is the common |
| 1136 | cgroup interface which should be used by various IO controlling |
| 1137 | policies. |
| 1138 | |
| 1139 | Currently, CFQ IO scheduler uses it to recognize task groups and |
| 1140 | control disk bandwidth allocation (proportional time slice allocation) |
| 1141 | to such task groups. It is also used by bio throttling logic in |
| 1142 | block layer to implement upper limit in IO rates on a device. |
| 1143 | |
| 1144 | This option only enables generic Block IO controller infrastructure. |
| 1145 | One needs to also enable actual IO controlling logic/policy. For |
| 1146 | enabling proportional weight division of disk bandwidth in CFQ, set |
| 1147 | CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set |
| 1148 | CONFIG_BLK_DEV_THROTTLING=y. |
| 1149 | |
| 1150 | See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information. |
| 1151 | |
| 1152 | config CGROUP_WRITEBACK |
| 1153 | bool |
| 1154 | depends on MEMCG && BLK_CGROUP |
| 1155 | default y |
| 1156 | |
| 1157 | menuconfig CGROUP_SCHED |
| 1158 | bool "CPU controller" |
| 1159 | default n |
| 1160 | help |
| 1161 | This feature lets CPU scheduler recognize task groups and control CPU |
| 1162 | bandwidth allocation to such task groups. It uses cgroups to group |
| 1163 | tasks. |
| 1164 | |
| 1165 | if CGROUP_SCHED |
| 1166 | config GROUP_SCHED_WEIGHT |
| 1167 | def_bool n |
| 1168 | |
| 1169 | config GROUP_SCHED_BANDWIDTH |
| 1170 | def_bool n |
| 1171 | |
| 1172 | config FAIR_GROUP_SCHED |
| 1173 | bool "Group scheduling for SCHED_OTHER" |
| 1174 | depends on CGROUP_SCHED |
| 1175 | select GROUP_SCHED_WEIGHT |
| 1176 | default CGROUP_SCHED |
| 1177 | |
| 1178 | config CFS_BANDWIDTH |
| 1179 | bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" |
| 1180 | depends on FAIR_GROUP_SCHED |
| 1181 | select GROUP_SCHED_BANDWIDTH |
| 1182 | default n |
| 1183 | help |
| 1184 | This option allows users to define CPU bandwidth rates (limits) for |
| 1185 | tasks running within the fair group scheduler. Groups with no limit |
| 1186 | set are considered to be unconstrained and will run with no |
| 1187 | restriction. |
| 1188 | See Documentation/scheduler/sched-bwc.rst for more information. |
| 1189 | |
| 1190 | config RT_GROUP_SCHED |
| 1191 | bool "Group scheduling for SCHED_RR/FIFO" |
| 1192 | depends on CGROUP_SCHED |
| 1193 | default n |
| 1194 | help |
| 1195 | This feature lets you explicitly allocate real CPU bandwidth |
| 1196 | to task groups. If enabled, it will also make it impossible to |
| 1197 | schedule realtime tasks for non-root users until you allocate |
| 1198 | realtime bandwidth for them. |
| 1199 | See Documentation/scheduler/sched-rt-group.rst for more information. |
| 1200 | |
| 1201 | config RT_GROUP_SCHED_DEFAULT_DISABLED |
| 1202 | bool "Require boot parameter to enable group scheduling for SCHED_RR/FIFO" |
| 1203 | depends on RT_GROUP_SCHED |
| 1204 | default n |
| 1205 | help |
| 1206 | When set, the RT group scheduling is disabled by default. The option |
| 1207 | is in inverted form so that mere RT_GROUP_SCHED enables the group |
| 1208 | scheduling. |
| 1209 | |
| 1210 | Say N if unsure. |
| 1211 | |
| 1212 | config EXT_GROUP_SCHED |
| 1213 | bool |
| 1214 | depends on SCHED_CLASS_EXT && CGROUP_SCHED |
| 1215 | select GROUP_SCHED_WEIGHT |
| 1216 | select GROUP_SCHED_BANDWIDTH |
| 1217 | default y |
| 1218 | |
| 1219 | endif #CGROUP_SCHED |
| 1220 | |
| 1221 | config EXT_SUB_SCHED |
| 1222 | def_bool y |
| 1223 | depends on SCHED_CLASS_EXT && CGROUPS |
| 1224 | |
| 1225 | config SCHED_MM_CID |
| 1226 | def_bool y |
| 1227 | depends on SMP && RSEQ |
| 1228 | |
| 1229 | config UCLAMP_TASK_GROUP |
| 1230 | bool "Utilization clamping per group of tasks" |
| 1231 | depends on CGROUP_SCHED |
| 1232 | depends on UCLAMP_TASK |
| 1233 | default n |
| 1234 | help |
| 1235 | This feature enables the scheduler to track the clamped utilization |
| 1236 | of each CPU based on RUNNABLE tasks currently scheduled on that CPU. |
| 1237 | |
| 1238 | When this option is enabled, the user can specify a min and max |
| 1239 | CPU bandwidth which is allowed for each single task in a group. |
| 1240 | The max bandwidth allows to clamp the maximum frequency a task |
| 1241 | can use, while the min bandwidth allows to define a minimum |
| 1242 | frequency a task will always use. |
| 1243 | |
| 1244 | When task group based utilization clamping is enabled, an eventually |
| 1245 | specified task-specific clamp value is constrained by the cgroup |
| 1246 | specified clamp value. Both minimum and maximum task clamping cannot |
| 1247 | be bigger than the corresponding clamping defined at task group level. |
| 1248 | |
| 1249 | If in doubt, say N. |
| 1250 | |
| 1251 | config CGROUP_PIDS |
| 1252 | bool "PIDs controller" |
| 1253 | help |
| 1254 | Provides enforcement of process number limits in the scope of a |
| 1255 | cgroup. Any attempt to fork more processes than is allowed in the |
| 1256 | cgroup will fail. PIDs are fundamentally a global resource because it |
| 1257 | is fairly trivial to reach PID exhaustion before you reach even a |
| 1258 | conservative kmemcg limit. As a result, it is possible to grind a |
| 1259 | system to halt without being limited by other cgroup policies. The |
| 1260 | PIDs controller is designed to stop this from happening. |
| 1261 | |
| 1262 | It should be noted that organisational operations (such as attaching |
| 1263 | to a cgroup hierarchy) will *not* be blocked by the PIDs controller, |
| 1264 | since the PIDs limit only affects a process's ability to fork, not to |
| 1265 | attach to a cgroup. |
| 1266 | |
| 1267 | config CGROUP_RDMA |
| 1268 | bool "RDMA controller" |
| 1269 | help |
| 1270 | Provides enforcement of RDMA resources defined by IB stack. |
| 1271 | It is fairly easy for consumers to exhaust RDMA resources, which |
| 1272 | can result into resource unavailability to other consumers. |
| 1273 | RDMA controller is designed to stop this from happening. |
| 1274 | Attaching processes with active RDMA resources to the cgroup |
| 1275 | hierarchy is allowed even if can cross the hierarchy's limit. |
| 1276 | |
| 1277 | config CGROUP_DMEM |
| 1278 | bool "Device memory controller (DMEM)" |
| 1279 | select PAGE_COUNTER |
| 1280 | help |
| 1281 | The DMEM controller allows compatible devices to restrict device |
| 1282 | memory usage based on the cgroup hierarchy. |
| 1283 | |
| 1284 | As an example, it allows you to restrict VRAM usage for applications |
| 1285 | in the DRM subsystem. |
| 1286 | |
| 1287 | config CGROUP_FREEZER |
| 1288 | bool "Freezer controller" |
| 1289 | help |
| 1290 | Provides a way to freeze and unfreeze all tasks in a |
| 1291 | cgroup. |
| 1292 | |
| 1293 | This option affects the ORIGINAL cgroup interface. The cgroup2 memory |
| 1294 | controller includes important in-kernel memory consumers per default. |
| 1295 | |
| 1296 | If you're using cgroup2, say N. |
| 1297 | |
| 1298 | config CGROUP_HUGETLB |
| 1299 | bool "HugeTLB controller" |
| 1300 | depends on HUGETLB_PAGE |
| 1301 | select PAGE_COUNTER |
| 1302 | default n |
| 1303 | help |
| 1304 | Provides a cgroup controller for HugeTLB pages. |
| 1305 | When you enable this, you can put a per cgroup limit on HugeTLB usage. |
| 1306 | The limit is enforced during page fault. Since HugeTLB doesn't |
| 1307 | support page reclaim, enforcing the limit at page fault time implies |
| 1308 | that, the application will get SIGBUS signal if it tries to access |
| 1309 | HugeTLB pages beyond its limit. This requires the application to know |
| 1310 | beforehand how much HugeTLB pages it would require for its use. The |
| 1311 | control group is tracked in the third page lru pointer. This means |
| 1312 | that we cannot use the controller with huge page less than 3 pages. |
| 1313 | |
| 1314 | config CPUSETS |
| 1315 | bool "Cpuset controller" |
| 1316 | depends on SMP |
| 1317 | select UNION_FIND |
| 1318 | select CPU_ISOLATION |
| 1319 | help |
| 1320 | This option will let you create and manage CPUSETs which |
| 1321 | allow dynamically partitioning a system into sets of CPUs and |
| 1322 | Memory Nodes and assigning tasks to run only within those sets. |
| 1323 | This is primarily useful on large SMP or NUMA systems. |
| 1324 | |
| 1325 | Say N if unsure. |
| 1326 | |
| 1327 | config CPUSETS_V1 |
| 1328 | bool "Legacy cgroup v1 cpusets controller" |
| 1329 | depends on CPUSETS |
| 1330 | default n |
| 1331 | help |
| 1332 | Legacy cgroup v1 cpusets controller which has been deprecated by |
| 1333 | cgroup v2 implementation. The v1 is there for legacy applications |
| 1334 | which haven't migrated to the new cgroup v2 interface yet. Legacy |
| 1335 | interface includes cpuset filesystem and /proc/<pid>/cpuset. If you |
| 1336 | do not have any such application then you are completely fine leaving |
| 1337 | this option disabled. |
| 1338 | |
| 1339 | Say N if unsure. |
| 1340 | |
| 1341 | config PROC_PID_CPUSET |
| 1342 | bool "Include legacy /proc/<pid>/cpuset file" |
| 1343 | depends on CPUSETS_V1 |
| 1344 | default y |
| 1345 | |
| 1346 | config CGROUP_DEVICE |
| 1347 | bool "Device controller" |
| 1348 | help |
| 1349 | Provides a cgroup controller implementing whitelists for |
| 1350 | devices which a process in the cgroup can mknod or open. |
| 1351 | |
| 1352 | config CGROUP_CPUACCT |
| 1353 | bool "Simple CPU accounting controller" |
| 1354 | help |
| 1355 | Provides a simple controller for monitoring the |
| 1356 | total CPU consumed by the tasks in a cgroup. |
| 1357 | |
| 1358 | config CGROUP_PERF |
| 1359 | bool "Perf controller" |
| 1360 | depends on PERF_EVENTS |
| 1361 | help |
| 1362 | This option extends the perf per-cpu mode to restrict monitoring |
| 1363 | to threads which belong to the cgroup specified and run on the |
| 1364 | designated cpu. Or this can be used to have cgroup ID in samples |
| 1365 | so that it can monitor performance events among cgroups. |
| 1366 | |
| 1367 | Say N if unsure. |
| 1368 | |
| 1369 | config CGROUP_BPF |
| 1370 | bool "Support for eBPF programs attached to cgroups" |
| 1371 | depends on BPF_SYSCALL |
| 1372 | select SOCK_CGROUP_DATA |
| 1373 | help |
| 1374 | Allow attaching eBPF programs to a cgroup using the bpf(2) |
| 1375 | syscall command BPF_PROG_ATTACH. |
| 1376 | |
| 1377 | In which context these programs are accessed depends on the type |
| 1378 | of attachment. For instance, programs that are attached using |
| 1379 | BPF_CGROUP_INET_INGRESS will be executed on the ingress path of |
| 1380 | inet sockets. |
| 1381 | |
| 1382 | config CGROUP_MISC |
| 1383 | bool "Misc resource controller" |
| 1384 | default n |
| 1385 | help |
| 1386 | Provides a controller for miscellaneous resources on a host. |
| 1387 | |
| 1388 | Miscellaneous scalar resources are the resources on the host system |
| 1389 | which cannot be abstracted like the other cgroups. This controller |
| 1390 | tracks and limits the miscellaneous resources used by a process |
| 1391 | attached to a cgroup hierarchy. |
| 1392 | |
| 1393 | For more information, please check misc cgroup section in |
| 1394 | /Documentation/admin-guide/cgroup-v2.rst. |
| 1395 | |
| 1396 | config CGROUP_DEBUG |
| 1397 | bool "Debug controller" |
| 1398 | default n |
| 1399 | depends on DEBUG_KERNEL |
| 1400 | help |
| 1401 | This option enables a simple controller that exports |
| 1402 | debugging information about the cgroups framework. This |
| 1403 | controller is for control cgroup debugging only. Its |
| 1404 | interfaces are not stable. |
| 1405 | |
| 1406 | Say N. |
| 1407 | |
| 1408 | config SOCK_CGROUP_DATA |
| 1409 | bool |
| 1410 | default n |
| 1411 | |
| 1412 | endif # CGROUPS |
| 1413 | |
| 1414 | menuconfig NAMESPACES |
| 1415 | bool "Namespaces support" if EXPERT |
| 1416 | depends on MULTIUSER |
| 1417 | default !EXPERT |
| 1418 | help |
| 1419 | Provides the way to make tasks work with different objects using |
| 1420 | the same id. For example same IPC id may refer to different objects |
| 1421 | or same user id or pid may refer to different tasks when used in |
| 1422 | different namespaces. |
| 1423 | |
| 1424 | if NAMESPACES |
| 1425 | |
| 1426 | config UTS_NS |
| 1427 | bool "UTS namespace" |
| 1428 | default y |
| 1429 | help |
| 1430 | In this namespace tasks see different info provided with the |
| 1431 | uname() system call |
| 1432 | |
| 1433 | config TIME_NS |
| 1434 | bool "TIME namespace" |
| 1435 | default y |
| 1436 | help |
| 1437 | In this namespace boottime and monotonic clocks can be set. |
| 1438 | The time will keep going with the same pace. |
| 1439 | |
| 1440 | config TIME_NS_VDSO |
| 1441 | def_bool TIME_NS && GENERIC_GETTIMEOFDAY |
| 1442 | |
| 1443 | config IPC_NS |
| 1444 | bool "IPC namespace" |
| 1445 | depends on (SYSVIPC || POSIX_MQUEUE) |
| 1446 | default y |
| 1447 | help |
| 1448 | In this namespace tasks work with IPC ids which correspond to |
| 1449 | different IPC objects in different namespaces. |
| 1450 | |
| 1451 | config USER_NS |
| 1452 | bool "User namespace" |
| 1453 | default n |
| 1454 | help |
| 1455 | This allows containers, i.e. vservers, to use user namespaces |
| 1456 | to provide different user info for different servers. |
| 1457 | |
| 1458 | When user namespaces are enabled in the kernel it is |
| 1459 | recommended that the MEMCG option also be enabled and that |
| 1460 | user-space use the memory control groups to limit the amount |
| 1461 | of memory a memory unprivileged users can use. |
| 1462 | |
| 1463 | If unsure, say N. |
| 1464 | |
| 1465 | config USER_NS_MAP_KUNIT_TEST |
| 1466 | tristate "KUint test for user namespace map insertion" if !KUNIT_ALL_TESTS |
| 1467 | depends on USER_NS && KUNIT |
| 1468 | default KUNIT_ALL_TESTS |
| 1469 | help |
| 1470 | This builds the KUnit test for user namespace uid/gid map insertion. |
| 1471 | It validates map insertion, limits, dynamic allocation of the |
| 1472 | extended extents array, and mapping sorting functions. |
| 1473 | |
| 1474 | If unsure, say N. |
| 1475 | |
| 1476 | config PID_NS |
| 1477 | bool "PID Namespaces" |
| 1478 | default y |
| 1479 | help |
| 1480 | Support process id namespaces. This allows having multiple |
| 1481 | processes with the same pid as long as they are in different |
| 1482 | pid namespaces. This is a building block of containers. |
| 1483 | |
| 1484 | config NET_NS |
| 1485 | bool "Network namespace" |
| 1486 | depends on NET |
| 1487 | default y |
| 1488 | help |
| 1489 | Allow user space to create what appear to be multiple instances |
| 1490 | of the network stack. |
| 1491 | |
| 1492 | endif # NAMESPACES |
| 1493 | |
| 1494 | config CHECKPOINT_RESTORE |
| 1495 | bool "Checkpoint/restore support" |
| 1496 | depends on PROC_FS |
| 1497 | select PROC_CHILDREN |
| 1498 | select KCMP |
| 1499 | default n |
| 1500 | help |
| 1501 | Enables additional kernel features in a sake of checkpoint/restore. |
| 1502 | In particular it adds auxiliary prctl codes to setup process text, |
| 1503 | data and heap segment sizes, and a few additional /proc filesystem |
| 1504 | entries. |
| 1505 | |
| 1506 | If unsure, say N here. |
| 1507 | |
| 1508 | config SCHED_AUTOGROUP |
| 1509 | bool "Automatic process group scheduling" |
| 1510 | select CGROUPS |
| 1511 | select CGROUP_SCHED |
| 1512 | select FAIR_GROUP_SCHED |
| 1513 | help |
| 1514 | This option optimizes the scheduler for common desktop workloads by |
| 1515 | automatically creating and populating task groups. This separation |
| 1516 | of workloads isolates aggressive CPU burners (like build jobs) from |
| 1517 | desktop applications. Task group autogeneration is currently based |
| 1518 | upon task session. |
| 1519 | |
| 1520 | config RELAY |
| 1521 | bool "Kernel->user space relay support (formerly relayfs)" |
| 1522 | select IRQ_WORK |
| 1523 | help |
| 1524 | This option enables support for relay interface support in |
| 1525 | certain file systems (such as debugfs). |
| 1526 | It is designed to provide an efficient mechanism for tools and |
| 1527 | facilities to relay large amounts of data from kernel space to |
| 1528 | user space. |
| 1529 | |
| 1530 | If unsure, say N. |
| 1531 | |
| 1532 | config BLK_DEV_INITRD |
| 1533 | bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" |
| 1534 | help |
| 1535 | The initial RAM filesystem is a ramfs which is loaded by the |
| 1536 | boot loader (loadlin or lilo) and that is mounted as root |
| 1537 | before the normal boot procedure. It is typically used to |
| 1538 | load modules needed to mount the "real" root file system, |
| 1539 | etc. See <file:Documentation/admin-guide/initrd.rst> for details. |
| 1540 | |
| 1541 | If RAM disk support (BLK_DEV_RAM) is also included, this |
| 1542 | also enables initial RAM disk (initrd) support and adds |
| 1543 | 15 Kbytes (more on some other architectures) to the kernel size. |
| 1544 | |
| 1545 | If unsure say Y. |
| 1546 | |
| 1547 | if BLK_DEV_INITRD |
| 1548 | |
| 1549 | source "usr/Kconfig" |
| 1550 | |
| 1551 | endif |
| 1552 | |
| 1553 | config BOOT_CONFIG |
| 1554 | bool "Boot config support" |
| 1555 | select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED |
| 1556 | help |
| 1557 | Extra boot config allows system admin to pass a config file as |
| 1558 | complemental extension of kernel cmdline when booting. |
| 1559 | The boot config file must be attached at the end of initramfs |
| 1560 | with checksum, size and magic word. |
| 1561 | See <file:Documentation/admin-guide/bootconfig.rst> for details. |
| 1562 | |
| 1563 | If unsure, say Y. |
| 1564 | |
| 1565 | config BOOT_CONFIG_FORCE |
| 1566 | bool "Force unconditional bootconfig processing" |
| 1567 | depends on BOOT_CONFIG |
| 1568 | default y if BOOT_CONFIG_EMBED |
| 1569 | help |
| 1570 | With this Kconfig option set, BOOT_CONFIG processing is carried |
| 1571 | out even when the "bootconfig" kernel-boot parameter is omitted. |
| 1572 | In fact, with this Kconfig option set, there is no way to |
| 1573 | make the kernel ignore the BOOT_CONFIG-supplied kernel-boot |
| 1574 | parameters. |
| 1575 | |
| 1576 | If unsure, say N. |
| 1577 | |
| 1578 | config BOOT_CONFIG_EMBED |
| 1579 | bool "Embed bootconfig file in the kernel" |
| 1580 | depends on BOOT_CONFIG |
| 1581 | help |
| 1582 | Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the |
| 1583 | kernel. Usually, the bootconfig file is loaded with the initrd |
| 1584 | image. But if the system doesn't support initrd, this option will |
| 1585 | help you by embedding a bootconfig file while building the kernel. |
| 1586 | |
| 1587 | If unsure, say N. |
| 1588 | |
| 1589 | config BOOT_CONFIG_EMBED_FILE |
| 1590 | string "Embedded bootconfig file path" |
| 1591 | depends on BOOT_CONFIG_EMBED |
| 1592 | help |
| 1593 | Specify a bootconfig file which will be embedded to the kernel. |
| 1594 | This bootconfig will be used if there is no initrd or no other |
| 1595 | bootconfig in the initrd. |
| 1596 | |
| 1597 | config ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG |
| 1598 | bool |
| 1599 | help |
| 1600 | Silent symbol; no C code reads it directly. Architectures |
| 1601 | select it once their setup_arch() calls |
| 1602 | xbc_prepend_embedded_cmdline() before parse_early_param(). |
| 1603 | Its only role is to gate the user-visible |
| 1604 | CMDLINE_FROM_BOOTCONFIG option per-arch, the same |
| 1605 | ARCH_SUPPORTS_* idiom used by ARCH_SUPPORTS_CFI, etc. |
| 1606 | |
| 1607 | config CMDLINE_FROM_BOOTCONFIG |
| 1608 | bool "Render embedded bootconfig as kernel cmdline at build time" |
| 1609 | depends on BOOT_CONFIG_EMBED_FILE != "" |
| 1610 | depends on ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG |
| 1611 | depends on CMDLINE = "" |
| 1612 | default n |
| 1613 | help |
| 1614 | Render the "kernel" subtree of the embedded bootconfig file into a |
| 1615 | flat cmdline string at kernel build time and prepend it to |
| 1616 | boot_command_line during early architecture setup. This makes |
| 1617 | early_param() handlers (e.g. mem=, earlycon=, loglevel=) see the |
| 1618 | values supplied via the embedded bootconfig. |
| 1619 | |
| 1620 | The runtime bootconfig parser is unaffected, so tree-structured |
| 1621 | consumers such as ftrace boot-time tracing keep working. |
| 1622 | |
| 1623 | Note: when an initrd also carries a bootconfig, its "kernel" |
| 1624 | subtree is still parsed at runtime, but the embedded "kernel" |
| 1625 | keys remain in boot_command_line for parse_early_param() and |
| 1626 | end up later than the initrd keys in saved_command_line, so |
| 1627 | parse_args() last-wins favors the embedded values. If you need |
| 1628 | initrd to override embedded kernel.* keys, leave this option |
| 1629 | off. |
| 1630 | |
| 1631 | If unsure, say N. |
| 1632 | |
| 1633 | config CMDLINE_LOG_WRAP_IDEAL_LEN |
| 1634 | int "Length to try to wrap the cmdline when logged at boot" |
| 1635 | default 1021 |
| 1636 | range 0 1021 |
| 1637 | help |
| 1638 | At boot time, the kernel command line is logged to the console. |
| 1639 | The log message will start with the prefix "Kernel command line: ". |
| 1640 | The log message will attempt to be wrapped (split into multiple log |
| 1641 | messages) at spaces based on CMDLINE_LOG_WRAP_IDEAL_LEN characters. |
| 1642 | If wrapping happens, each log message will start with the prefix and |
| 1643 | all but the last message will end with " \". Messages may exceed the |
| 1644 | ideal length if a place to wrap isn't found before the specified |
| 1645 | number of characters. |
| 1646 | |
| 1647 | A value of 0 disables wrapping, though be warned that the maximum |
| 1648 | length of a log message (1021 characters) may cause the cmdline to |
| 1649 | be truncated. |
| 1650 | |
| 1651 | config INITRAMFS_PRESERVE_MTIME |
| 1652 | bool "Preserve cpio archive mtimes in initramfs" |
| 1653 | depends on BLK_DEV_INITRD |
| 1654 | default y |
| 1655 | help |
| 1656 | Each entry in an initramfs cpio archive carries an mtime value. When |
| 1657 | enabled, extracted cpio items take this mtime, with directory mtime |
| 1658 | setting deferred until after creation of any child entries. |
| 1659 | |
| 1660 | If unsure, say Y. |
| 1661 | |
| 1662 | config INITRAMFS_TEST |
| 1663 | bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS |
| 1664 | depends on BLK_DEV_INITRD && KUNIT=y |
| 1665 | default KUNIT_ALL_TESTS |
| 1666 | help |
| 1667 | Build KUnit tests for initramfs. See Documentation/dev-tools/kunit |
| 1668 | |
| 1669 | choice |
| 1670 | prompt "Compiler optimization level" |
| 1671 | default CC_OPTIMIZE_FOR_PERFORMANCE |
| 1672 | |
| 1673 | config CC_OPTIMIZE_FOR_PERFORMANCE |
| 1674 | bool "Optimize for performance (-O2)" |
| 1675 | help |
| 1676 | This is the default optimization level for the kernel, building |
| 1677 | with the "-O2" compiler flag for best performance and most |
| 1678 | helpful compile-time warnings. |
| 1679 | |
| 1680 | config CC_OPTIMIZE_FOR_SIZE |
| 1681 | bool "Optimize for size (-Os)" |
| 1682 | help |
| 1683 | Choosing this option will pass "-Os" to your compiler resulting |
| 1684 | in a smaller kernel. |
| 1685 | |
| 1686 | endchoice |
| 1687 | |
| 1688 | config HAVE_LD_DEAD_CODE_DATA_ELIMINATION |
| 1689 | bool |
| 1690 | help |
| 1691 | This requires that the arch annotates or otherwise protects |
| 1692 | its external entry points from being discarded. Linker scripts |
| 1693 | must also merge .text.*, .data.*, and .bss.* correctly into |
| 1694 | output sections. Care must be taken not to pull in unrelated |
| 1695 | sections (e.g., '.text.init'). Typically '.' in section names |
| 1696 | is used to distinguish them from label names / C identifiers. |
| 1697 | |
| 1698 | config LD_DEAD_CODE_DATA_ELIMINATION |
| 1699 | bool "Dead code and data elimination (EXPERIMENTAL)" |
| 1700 | depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION |
| 1701 | depends on EXPERT |
| 1702 | depends on $(cc-option,-ffunction-sections -fdata-sections) |
| 1703 | depends on $(ld-option,--gc-sections) |
| 1704 | help |
| 1705 | Enable this if you want to do dead code and data elimination with |
| 1706 | the linker by compiling with -ffunction-sections -fdata-sections, |
| 1707 | and linking with --gc-sections. |
| 1708 | |
| 1709 | This can reduce on disk and in-memory size of the kernel |
| 1710 | code and static data, particularly for small configs and |
| 1711 | on small systems. This has the possibility of introducing |
| 1712 | silently broken kernel if the required annotations are not |
| 1713 | present. This option is not well tested yet, so use at your |
| 1714 | own risk. |
| 1715 | |
| 1716 | config LD_ORPHAN_WARN |
| 1717 | def_bool y |
| 1718 | depends on ARCH_WANT_LD_ORPHAN_WARN |
| 1719 | depends on $(ld-option,--orphan-handling=warn) |
| 1720 | depends on $(ld-option,--orphan-handling=error) |
| 1721 | |
| 1722 | config LD_ORPHAN_WARN_LEVEL |
| 1723 | string |
| 1724 | depends on LD_ORPHAN_WARN |
| 1725 | default "error" if WERROR |
| 1726 | default "warn" |
| 1727 | |
| 1728 | config HAVE_UID16 |
| 1729 | bool |
| 1730 | |
| 1731 | config SYSCTL_EXCEPTION_TRACE |
| 1732 | bool |
| 1733 | help |
| 1734 | Enable support for /proc/sys/debug/exception-trace. |
| 1735 | |
| 1736 | config SYSCTL_ARCH_UNALIGN_NO_WARN |
| 1737 | bool |
| 1738 | help |
| 1739 | Enable support for /proc/sys/kernel/ignore-unaligned-usertrap |
| 1740 | Allows arch to define/use @no_unaligned_warning to possibly warn |
| 1741 | about unaligned access emulation going on under the hood. |
| 1742 | |
| 1743 | config SYSCTL_ARCH_UNALIGN_ALLOW |
| 1744 | bool |
| 1745 | help |
| 1746 | Enable support for /proc/sys/kernel/unaligned-trap |
| 1747 | Allows arches to define/use @unaligned_enabled to runtime toggle |
| 1748 | the unaligned access emulation. |
| 1749 | see arch/parisc/kernel/unaligned.c for reference |
| 1750 | |
| 1751 | config SYSFS_SYSCALL |
| 1752 | bool "Sysfs syscall support" |
| 1753 | default n |
| 1754 | help |
| 1755 | sys_sysfs is an obsolete system call no longer supported in libc. |
| 1756 | Note that disabling this option is more secure but might break |
| 1757 | compatibility with some systems. |
| 1758 | |
| 1759 | If unsure say N here. |
| 1760 | |
| 1761 | config HAVE_PCSPKR_PLATFORM |
| 1762 | bool |
| 1763 | |
| 1764 | menuconfig EXPERT |
| 1765 | bool "Configure standard kernel features (expert users)" |
| 1766 | # Unhide debug options, to make the on-by-default options visible |
| 1767 | select DEBUG_KERNEL |
| 1768 | help |
| 1769 | This option allows certain base kernel options and settings |
| 1770 | to be disabled or tweaked. This is for specialized |
| 1771 | environments which can tolerate a "non-standard" kernel. |
| 1772 | Only use this if you really know what you are doing. |
| 1773 | |
| 1774 | config UID16 |
| 1775 | bool "Enable 16-bit UID system calls" if EXPERT |
| 1776 | depends on HAVE_UID16 && MULTIUSER |
| 1777 | default y |
| 1778 | help |
| 1779 | This enables the legacy 16-bit UID syscall wrappers. |
| 1780 | |
| 1781 | config MULTIUSER |
| 1782 | bool "Multiple users, groups and capabilities support" if EXPERT |
| 1783 | default y |
| 1784 | help |
| 1785 | This option enables support for non-root users, groups and |
| 1786 | capabilities. |
| 1787 | |
| 1788 | If you say N here, all processes will run with UID 0, GID 0, and all |
| 1789 | possible capabilities. Saying N here also compiles out support for |
| 1790 | system calls related to UIDs, GIDs, and capabilities, such as setuid, |
| 1791 | setgid, and capset. |
| 1792 | |
| 1793 | If unsure, say Y here. |
| 1794 | |
| 1795 | config SGETMASK_SYSCALL |
| 1796 | bool "sgetmask/ssetmask syscalls support" if EXPERT |
| 1797 | default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH |
| 1798 | help |
| 1799 | sys_sgetmask and sys_ssetmask are obsolete system calls |
| 1800 | no longer supported in libc but still enabled by default in some |
| 1801 | architectures. |
| 1802 | |
| 1803 | If unsure, leave the default option here. |
| 1804 | |
| 1805 | config FHANDLE |
| 1806 | bool "open by fhandle syscalls" if EXPERT |
| 1807 | select EXPORTFS |
| 1808 | default y |
| 1809 | help |
| 1810 | If you say Y here, a user level program will be able to map |
| 1811 | file names to handle and then later use the handle for |
| 1812 | different file system operations. This is useful in implementing |
| 1813 | userspace file servers, which now track files using handles instead |
| 1814 | of names. The handle would remain the same even if file names |
| 1815 | get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) |
| 1816 | syscalls. |
| 1817 | |
| 1818 | config POSIX_TIMERS |
| 1819 | bool "Posix Clocks & timers" if EXPERT |
| 1820 | default y |
| 1821 | help |
| 1822 | This includes native support for POSIX timers to the kernel. |
| 1823 | Some embedded systems have no use for them and therefore they |
| 1824 | can be configured out to reduce the size of the kernel image. |
| 1825 | |
| 1826 | When this option is disabled, the following syscalls won't be |
| 1827 | available: timer_create, timer_gettime: timer_getoverrun, |
| 1828 | timer_settime, timer_delete, clock_adjtime, getitimer, |
| 1829 | setitimer, alarm. Furthermore, the clock_settime, clock_gettime, |
| 1830 | clock_getres and clock_nanosleep syscalls will be limited to |
| 1831 | CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. |
| 1832 | |
| 1833 | If unsure say y. |
| 1834 | |
| 1835 | config PRINTK |
| 1836 | default y |
| 1837 | bool "Enable support for printk" if EXPERT |
| 1838 | select IRQ_WORK |
| 1839 | help |
| 1840 | This option enables normal printk support. Removing it |
| 1841 | eliminates most of the message strings from the kernel image |
| 1842 | and makes the kernel more or less silent. As this makes it |
| 1843 | very difficult to diagnose system problems, saying N here is |
| 1844 | strongly discouraged. |
| 1845 | |
| 1846 | config PRINTK_RINGBUFFER_KUNIT_TEST |
| 1847 | tristate "KUnit Test for the printk ringbuffer" if !KUNIT_ALL_TESTS |
| 1848 | depends on PRINTK && KUNIT |
| 1849 | default KUNIT_ALL_TESTS |
| 1850 | help |
| 1851 | This builds the printk ringbuffer KUnit test suite. |
| 1852 | |
| 1853 | For more information on KUnit and unit tests in general, please refer |
| 1854 | to the KUnit documentation. |
| 1855 | |
| 1856 | If unsure, say N. |
| 1857 | |
| 1858 | config BUG |
| 1859 | bool "BUG() support" if EXPERT |
| 1860 | default y |
| 1861 | help |
| 1862 | Disabling this option eliminates support for BUG and WARN, reducing |
| 1863 | the size of your kernel image and potentially quietly ignoring |
| 1864 | numerous fatal conditions. You should only consider disabling this |
| 1865 | option for embedded systems with no facilities for reporting errors. |
| 1866 | Just say Y. |
| 1867 | |
| 1868 | config ELF_CORE |
| 1869 | depends on COREDUMP |
| 1870 | default y |
| 1871 | bool "Enable ELF core dumps" if EXPERT |
| 1872 | help |
| 1873 | Enable support for generating core dumps. Disabling saves about 4k. |
| 1874 | |
| 1875 | |
| 1876 | config PCSPKR_PLATFORM |
| 1877 | bool "Enable PC-Speaker support" if EXPERT |
| 1878 | depends on HAVE_PCSPKR_PLATFORM |
| 1879 | select I8253_LOCK |
| 1880 | default y |
| 1881 | help |
| 1882 | This option allows to disable the internal PC-Speaker |
| 1883 | support, saving some memory. |
| 1884 | |
| 1885 | config BASE_SMALL |
| 1886 | bool "Enable smaller-sized data structures for core" if EXPERT |
| 1887 | help |
| 1888 | Enabling this option reduces the size of miscellaneous core |
| 1889 | kernel data structures. This saves memory on small machines, |
| 1890 | but may reduce performance. |
| 1891 | |
| 1892 | config FUTEX |
| 1893 | bool "Enable futex support" if EXPERT |
| 1894 | depends on !(SPARC32 && SMP) |
| 1895 | default y |
| 1896 | imply RT_MUTEXES |
| 1897 | help |
| 1898 | Disabling this option will cause the kernel to be built without |
| 1899 | support for "fast userspace mutexes". The resulting kernel may not |
| 1900 | run glibc-based applications correctly. |
| 1901 | |
| 1902 | config FUTEX_PI |
| 1903 | bool |
| 1904 | depends on FUTEX && RT_MUTEXES |
| 1905 | default y |
| 1906 | |
| 1907 | config FUTEX_PRIVATE_HASH |
| 1908 | bool |
| 1909 | depends on FUTEX && !BASE_SMALL && MMU |
| 1910 | default y |
| 1911 | |
| 1912 | config FUTEX_MPOL |
| 1913 | bool |
| 1914 | depends on FUTEX && NUMA |
| 1915 | default y |
| 1916 | |
| 1917 | config HAVE_FUTEX_ROBUST_UNLOCK |
| 1918 | bool |
| 1919 | |
| 1920 | config FUTEX_ROBUST_UNLOCK |
| 1921 | def_bool FUTEX && GENERIC_IRQ_ENTRY && RSEQ && HAVE_FUTEX_ROBUST_UNLOCK |
| 1922 | |
| 1923 | config EPOLL |
| 1924 | bool "Enable eventpoll support" if EXPERT |
| 1925 | default y |
| 1926 | help |
| 1927 | Disabling this option will cause the kernel to be built without |
| 1928 | support for epoll family of system calls. |
| 1929 | |
| 1930 | config SIGNALFD |
| 1931 | bool "Enable signalfd() system call" if EXPERT |
| 1932 | default y |
| 1933 | help |
| 1934 | Enable the signalfd() system call that allows to receive signals |
| 1935 | on a file descriptor. |
| 1936 | |
| 1937 | If unsure, say Y. |
| 1938 | |
| 1939 | config TIMERFD |
| 1940 | bool "Enable timerfd() system call" if EXPERT |
| 1941 | default y |
| 1942 | help |
| 1943 | Enable the timerfd() system call that allows to receive timer |
| 1944 | events on a file descriptor. |
| 1945 | |
| 1946 | If unsure, say Y. |
| 1947 | |
| 1948 | config EVENTFD |
| 1949 | bool "Enable eventfd() system call" if EXPERT |
| 1950 | default y |
| 1951 | help |
| 1952 | Enable the eventfd() system call that allows to receive both |
| 1953 | kernel notification (ie. KAIO) or userspace notifications. |
| 1954 | |
| 1955 | If unsure, say Y. |
| 1956 | |
| 1957 | config SHMEM |
| 1958 | bool "Use full shmem filesystem" if EXPERT |
| 1959 | default y |
| 1960 | depends on MMU |
| 1961 | help |
| 1962 | The shmem is an internal filesystem used to manage shared memory. |
| 1963 | It is backed by swap and manages resource limits. It is also exported |
| 1964 | to userspace as tmpfs if TMPFS is enabled. Disabling this |
| 1965 | option replaces shmem and tmpfs with the much simpler ramfs code, |
| 1966 | which may be appropriate on small systems without swap. |
| 1967 | |
| 1968 | config AIO |
| 1969 | bool "Enable AIO support" if EXPERT |
| 1970 | default y |
| 1971 | help |
| 1972 | This option enables POSIX asynchronous I/O which may by used |
| 1973 | by some high performance threaded applications. Disabling |
| 1974 | this option saves about 7k. |
| 1975 | |
| 1976 | config IO_URING |
| 1977 | bool "Enable IO uring support" if EXPERT |
| 1978 | select IO_WQ |
| 1979 | default y |
| 1980 | help |
| 1981 | This option enables support for the io_uring interface, enabling |
| 1982 | applications to submit and complete IO through submission and |
| 1983 | completion rings that are shared between the kernel and application. |
| 1984 | |
| 1985 | config GCOV_PROFILE_URING |
| 1986 | bool "Enable GCOV profiling on the io_uring subsystem" |
| 1987 | depends on IO_URING && GCOV_KERNEL |
| 1988 | help |
| 1989 | Enable GCOV profiling on the io_uring subsystem, to facilitate |
| 1990 | code coverage testing. |
| 1991 | |
| 1992 | If unsure, say N. |
| 1993 | |
| 1994 | Note that this will have a negative impact on the performance of |
| 1995 | the io_uring subsystem, hence this should only be enabled for |
| 1996 | specific test purposes. |
| 1997 | |
| 1998 | config IO_URING_MOCK_FILE |
| 1999 | tristate "Enable io_uring mock files (Experimental)" if EXPERT |
| 2000 | default n |
| 2001 | depends on IO_URING |
| 2002 | help |
| 2003 | Enable mock files for io_uring subsystem testing. The ABI might |
| 2004 | still change, so it's still experimental and should only be enabled |
| 2005 | for specific test purposes. |
| 2006 | |
| 2007 | If unsure, say N. |
| 2008 | |
| 2009 | config ADVISE_SYSCALLS |
| 2010 | bool "Enable madvise/fadvise syscalls" if EXPERT |
| 2011 | default y |
| 2012 | help |
| 2013 | This option enables the madvise and fadvise syscalls, used by |
| 2014 | applications to advise the kernel about their future memory or file |
| 2015 | usage, improving performance. If building an embedded system where no |
| 2016 | applications use these syscalls, you can disable this option to save |
| 2017 | space. |
| 2018 | |
| 2019 | config MEMBARRIER |
| 2020 | bool "Enable membarrier() system call" if EXPERT |
| 2021 | default y |
| 2022 | help |
| 2023 | Enable the membarrier() system call that allows issuing memory |
| 2024 | barriers across all running threads, which can be used to distribute |
| 2025 | the cost of user-space memory barriers asymmetrically by transforming |
| 2026 | pairs of memory barriers into pairs consisting of membarrier() and a |
| 2027 | compiler barrier. |
| 2028 | |
| 2029 | If unsure, say Y. |
| 2030 | |
| 2031 | config KCMP |
| 2032 | bool "Enable kcmp() system call" if EXPERT |
| 2033 | help |
| 2034 | Enable the kernel resource comparison system call. It provides |
| 2035 | user-space with the ability to compare two processes to see if they |
| 2036 | share a common resource, such as a file descriptor or even virtual |
| 2037 | memory space. |
| 2038 | |
| 2039 | If unsure, say N. |
| 2040 | |
| 2041 | config RSEQ |
| 2042 | bool "Enable rseq() system call" if EXPERT |
| 2043 | default y |
| 2044 | depends on HAVE_RSEQ |
| 2045 | select MEMBARRIER |
| 2046 | help |
| 2047 | Enable the restartable sequences system call. It provides a |
| 2048 | user-space cache for the current CPU number value, which |
| 2049 | speeds up getting the current CPU number from user-space, |
| 2050 | as well as an ABI to speed up user-space operations on |
| 2051 | per-CPU data. |
| 2052 | |
| 2053 | If unsure, say Y. |
| 2054 | |
| 2055 | config RSEQ_SLICE_EXTENSION |
| 2056 | bool "Enable rseq-based time slice extension mechanism" |
| 2057 | depends on RSEQ && HIGH_RES_TIMERS && GENERIC_ENTRY && HAVE_GENERIC_TIF_BITS |
| 2058 | help |
| 2059 | Allows userspace to request a limited time slice extension when |
| 2060 | returning from an interrupt to user space via the RSEQ shared |
| 2061 | data ABI. If granted, that allows to complete a critical section, |
| 2062 | so that other threads are not stuck on a conflicted resource, |
| 2063 | while the task is scheduled out. |
| 2064 | |
| 2065 | If unsure, say N. |
| 2066 | |
| 2067 | config RSEQ_STATS |
| 2068 | default n |
| 2069 | bool "Enable lightweight statistics of restartable sequences" if EXPERT |
| 2070 | depends on RSEQ && DEBUG_FS |
| 2071 | help |
| 2072 | Enable lightweight counters which expose information about the |
| 2073 | frequency of RSEQ operations via debugfs. Mostly interesting for |
| 2074 | kernel debugging or performance analysis. While lightweight it's |
| 2075 | still adding code into the user/kernel mode transitions. |
| 2076 | |
| 2077 | If unsure, say N. |
| 2078 | |
| 2079 | config RSEQ_DEBUG_DEFAULT_ENABLE |
| 2080 | default n |
| 2081 | bool "Enable restartable sequences debug mode by default" if EXPERT |
| 2082 | depends on RSEQ |
| 2083 | help |
| 2084 | This enables the static branch for debug mode of restartable |
| 2085 | sequences. |
| 2086 | |
| 2087 | This also can be controlled on the kernel command line via the |
| 2088 | command line parameter "rseq_debug=0/1" and through debugfs. |
| 2089 | |
| 2090 | If unsure, say N. |
| 2091 | |
| 2092 | config DEBUG_RSEQ |
| 2093 | default n |
| 2094 | bool "Enable debugging of rseq() system call" if EXPERT |
| 2095 | depends on RSEQ && DEBUG_KERNEL && !GENERIC_ENTRY |
| 2096 | select RSEQ_DEBUG_DEFAULT_ENABLE |
| 2097 | help |
| 2098 | Enable extra debugging checks for the rseq system call. |
| 2099 | |
| 2100 | If unsure, say N. |
| 2101 | |
| 2102 | config CACHESTAT_SYSCALL |
| 2103 | bool "Enable cachestat() system call" if EXPERT |
| 2104 | default y |
| 2105 | help |
| 2106 | Enable the cachestat system call, which queries the page cache |
| 2107 | statistics of a file (number of cached pages, dirty pages, |
| 2108 | pages marked for writeback, (recently) evicted pages). |
| 2109 | |
| 2110 | If unsure say Y here. |
| 2111 | |
| 2112 | config KALLSYMS |
| 2113 | bool "Load all symbols for debugging/ksymoops" if EXPERT |
| 2114 | default y |
| 2115 | help |
| 2116 | Say Y here to let the kernel print out symbolic crash information and |
| 2117 | symbolic stack backtraces. This increases the size of the kernel |
| 2118 | somewhat, as all symbols have to be loaded into the kernel image. |
| 2119 | |
| 2120 | config KALLSYMS_SELFTEST |
| 2121 | bool "Test the basic functions and performance of kallsyms" |
| 2122 | depends on KALLSYMS |
| 2123 | default n |
| 2124 | help |
| 2125 | Test the basic functions and performance of some interfaces, such as |
| 2126 | kallsyms_lookup_name. It also calculates the compression rate of the |
| 2127 | kallsyms compression algorithm for the current symbol set. |
| 2128 | |
| 2129 | Start self-test automatically after system startup. Suggest executing |
| 2130 | "dmesg | grep kallsyms_selftest" to collect test results. "finish" is |
| 2131 | displayed in the last line, indicating that the test is complete. |
| 2132 | |
| 2133 | config KALLSYMS_ALL |
| 2134 | bool "Include all symbols in kallsyms" |
| 2135 | depends on DEBUG_KERNEL && KALLSYMS |
| 2136 | help |
| 2137 | Normally kallsyms only contains the symbols of functions for nicer |
| 2138 | OOPS messages and backtraces (i.e., symbols from the text and inittext |
| 2139 | sections). This is sufficient for most cases. And only if you want to |
| 2140 | enable kernel live patching, or other less common use cases (e.g., |
| 2141 | when a debugger is used) all symbols are required (i.e., names of |
| 2142 | variables from the data sections, etc). |
| 2143 | |
| 2144 | This option makes sure that all symbols are loaded into the kernel |
| 2145 | image (i.e., symbols from all sections) in cost of increased kernel |
| 2146 | size (depending on the kernel configuration, it may be 300KiB or |
| 2147 | something like this). |
| 2148 | |
| 2149 | Say N unless you really need all symbols, or kernel live patching. |
| 2150 | |
| 2151 | # end of the "standard kernel features (expert users)" menu |
| 2152 | |
| 2153 | config ARCH_HAS_MEMBARRIER_CALLBACKS |
| 2154 | bool |
| 2155 | |
| 2156 | config ARCH_HAS_MEMBARRIER_SYNC_CORE |
| 2157 | bool |
| 2158 | |
| 2159 | config ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS |
| 2160 | bool |
| 2161 | help |
| 2162 | Control MSEAL_SYSTEM_MAPPINGS access based on architecture. |
| 2163 | |
| 2164 | A 64-bit kernel is required for the memory sealing feature. |
| 2165 | No specific hardware features from the CPU are needed. |
| 2166 | |
| 2167 | To enable this feature, the architecture needs to update their |
| 2168 | special mappings calls to include the sealing flag and confirm |
| 2169 | that it doesn't unmap/remap system mappings during the life |
| 2170 | time of the process. The existence of this flag for an architecture |
| 2171 | implies that it does not require the remapping of the system |
| 2172 | mappings during process lifetime, so sealing these mappings is safe |
| 2173 | from a kernel perspective. |
| 2174 | |
| 2175 | After the architecture enables this, a distribution can set |
| 2176 | CONFIG_MSEAL_SYSTEM_MAPPINGS to manage access to the feature. |
| 2177 | |
| 2178 | For complete descriptions of memory sealing, please see |
| 2179 | Documentation/userspace-api/mseal.rst |
| 2180 | |
| 2181 | config HAVE_PERF_EVENTS |
| 2182 | bool |
| 2183 | help |
| 2184 | See tools/perf/design.txt for details. |
| 2185 | |
| 2186 | config GUEST_PERF_EVENTS |
| 2187 | bool |
| 2188 | depends on HAVE_PERF_EVENTS |
| 2189 | |
| 2190 | config PERF_GUEST_MEDIATED_PMU |
| 2191 | bool |
| 2192 | depends on GUEST_PERF_EVENTS |
| 2193 | |
| 2194 | config PERF_USE_VMALLOC |
| 2195 | bool |
| 2196 | help |
| 2197 | See tools/perf/design.txt for details |
| 2198 | |
| 2199 | menu "Kernel Performance Events And Counters" |
| 2200 | |
| 2201 | config PERF_EVENTS |
| 2202 | bool "Kernel performance events and counters" |
| 2203 | default y if PROFILING |
| 2204 | depends on HAVE_PERF_EVENTS |
| 2205 | select IRQ_WORK |
| 2206 | help |
| 2207 | Enable kernel support for various performance events provided |
| 2208 | by software and hardware. |
| 2209 | |
| 2210 | Software events are supported either built-in or via the |
| 2211 | use of generic tracepoints. |
| 2212 | |
| 2213 | Most modern CPUs support performance events via performance |
| 2214 | counter registers. These registers count the number of certain |
| 2215 | types of hw events: such as instructions executed, cachemisses |
| 2216 | suffered, or branches mis-predicted - without slowing down the |
| 2217 | kernel or applications. These registers can also trigger interrupts |
| 2218 | when a threshold number of events have passed - and can thus be |
| 2219 | used to profile the code that runs on that CPU. |
| 2220 | |
| 2221 | The Linux Performance Event subsystem provides an abstraction of |
| 2222 | these software and hardware event capabilities, available via a |
| 2223 | system call and used by the "perf" utility in tools/perf/. It |
| 2224 | provides per task and per CPU counters, and it provides event |
| 2225 | capabilities on top of those. |
| 2226 | |
| 2227 | Say Y if unsure. |
| 2228 | |
| 2229 | config DEBUG_PERF_USE_VMALLOC |
| 2230 | default n |
| 2231 | bool "Debug: use vmalloc to back perf mmap() buffers" |
| 2232 | depends on PERF_EVENTS && DEBUG_KERNEL && !PPC |
| 2233 | select PERF_USE_VMALLOC |
| 2234 | help |
| 2235 | Use vmalloc memory to back perf mmap() buffers. |
| 2236 | |
| 2237 | Mostly useful for debugging the vmalloc code on platforms |
| 2238 | that don't require it. |
| 2239 | |
| 2240 | Say N if unsure. |
| 2241 | |
| 2242 | endmenu |
| 2243 | |
| 2244 | config SYSTEM_DATA_VERIFICATION |
| 2245 | def_bool n |
| 2246 | select SYSTEM_TRUSTED_KEYRING |
| 2247 | select KEYS |
| 2248 | select CRYPTO |
| 2249 | select CRYPTO_RSA |
| 2250 | select ASYMMETRIC_KEY_TYPE |
| 2251 | select ASYMMETRIC_PUBLIC_KEY_SUBTYPE |
| 2252 | select ASN1 |
| 2253 | select OID_REGISTRY |
| 2254 | select X509_CERTIFICATE_PARSER |
| 2255 | select PKCS7_MESSAGE_PARSER |
| 2256 | help |
| 2257 | Provide PKCS#7 message verification using the contents of the system |
| 2258 | trusted keyring to provide public keys. This then can be used for |
| 2259 | module verification, kexec image verification and firmware blob |
| 2260 | verification. |
| 2261 | |
| 2262 | config PROFILING |
| 2263 | bool "Profiling support" |
| 2264 | help |
| 2265 | Say Y here to enable the extended profiling support mechanisms used |
| 2266 | by profilers. |
| 2267 | |
| 2268 | config RUST |
| 2269 | bool "Rust support" |
| 2270 | depends on HAVE_RUST |
| 2271 | depends on RUST_IS_AVAILABLE |
| 2272 | select EXTENDED_MODVERSIONS if MODVERSIONS |
| 2273 | depends on !MODVERSIONS || GENDWARFKSYMS |
| 2274 | depends on !GCC_PLUGIN_RANDSTRUCT |
| 2275 | depends on !RANDSTRUCT |
| 2276 | depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO) |
| 2277 | depends on !CFI || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC |
| 2278 | select CFI_ICALL_NORMALIZE_INTEGERS if CFI |
| 2279 | depends on !KASAN || CC_IS_CLANG |
| 2280 | depends on !KASAN_SW_TAGS || RUSTC_VERSION >= 109600 |
| 2281 | help |
| 2282 | Enables Rust support in the kernel. |
| 2283 | |
| 2284 | This allows other Rust-related options, like drivers written in Rust, |
| 2285 | to be selected. |
| 2286 | |
| 2287 | It is also required to be able to load external kernel modules |
| 2288 | written in Rust. |
| 2289 | |
| 2290 | See Documentation/rust/ for more information. |
| 2291 | |
| 2292 | If unsure, say N. |
| 2293 | |
| 2294 | source "rust/kernel/Kconfig.test" |
| 2295 | |
| 2296 | config RUSTC_VERSION_TEXT |
| 2297 | string |
| 2298 | depends on RUST |
| 2299 | default "$(RUSTC_VERSION_TEXT)" |
| 2300 | help |
| 2301 | See `CC_VERSION_TEXT`. |
| 2302 | |
| 2303 | config BINDGEN_VERSION_TEXT |
| 2304 | string |
| 2305 | depends on RUST |
| 2306 | default "$(shell,$(BINDGEN) --version 2>/dev/null)" |
| 2307 | |
| 2308 | # |
| 2309 | # Place an empty function call at each tracepoint site. Can be |
| 2310 | # dynamically changed for a probe function. |
| 2311 | # |
| 2312 | config TRACEPOINTS |
| 2313 | bool |
| 2314 | select TASKS_TRACE_RCU |
| 2315 | |
| 2316 | source "kernel/Kconfig.kexec" |
| 2317 | |
| 2318 | source "kernel/liveupdate/Kconfig" |
| 2319 | |
| 2320 | endmenu # General setup |
| 2321 | |
| 2322 | source "arch/Kconfig" |
| 2323 | |
| 2324 | config RT_MUTEXES |
| 2325 | bool |
| 2326 | default y if PREEMPT_RT |
| 2327 | |
| 2328 | config MODULE_SIG_FORMAT |
| 2329 | def_bool n |
| 2330 | select SYSTEM_DATA_VERIFICATION |
| 2331 | |
| 2332 | source "kernel/module/Kconfig" |
| 2333 | |
| 2334 | config INIT_ALL_POSSIBLE |
| 2335 | bool |
| 2336 | help |
| 2337 | Back when each arch used to define their own cpu_online_mask and |
| 2338 | cpu_possible_mask, some of them chose to initialize cpu_possible_mask |
| 2339 | with all 1s, and others with all 0s. When they were centralised, |
| 2340 | it was better to provide this option than to break all the archs |
| 2341 | and have several arch maintainers pursuing me down dark alleys. |
| 2342 | |
| 2343 | source "block/Kconfig" |
| 2344 | |
| 2345 | config PREEMPT_NOTIFIERS |
| 2346 | bool |
| 2347 | |
| 2348 | config PADATA |
| 2349 | depends on SMP |
| 2350 | bool |
| 2351 | |
| 2352 | config ASN1 |
| 2353 | tristate |
| 2354 | help |
| 2355 | Build a simple ASN.1 grammar compiler that produces a bytecode output |
| 2356 | that can be interpreted by the ASN.1 stream decoder and used to |
| 2357 | inform it as to what tags are to be expected in a stream and what |
| 2358 | functions to call on what tags. |
| 2359 | |
| 2360 | source "kernel/Kconfig.locks" |
| 2361 | |
| 2362 | config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE |
| 2363 | bool |
| 2364 | |
| 2365 | config ARCH_HAS_PREPARE_SYNC_CORE_CMD |
| 2366 | bool |
| 2367 | |
| 2368 | config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE |
| 2369 | bool |
| 2370 | |
| 2371 | # It may be useful for an architecture to override the definitions of the |
| 2372 | # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> |
| 2373 | # and the COMPAT_ variants in <linux/compat.h>, in particular to use a |
| 2374 | # different calling convention for syscalls. They can also override the |
| 2375 | # macros for not-implemented syscalls in kernel/sys_ni.c and |
| 2376 | # kernel/time/posix-stubs.c. All these overrides need to be available in |
| 2377 | # <asm/syscall_wrapper.h>. |
| 2378 | config ARCH_HAS_SYSCALL_WRAPPER |
| 2379 | def_bool n |