1# SPDX-License-Identifier: GPL-2.0-only 2config 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 19config CC_IS_GCC 20 def_bool $(success,test "$(cc-name)" = GCC) 21 22config GCC_VERSION 23 int 24 default $(cc-version) if CC_IS_GCC 25 default 0 26 27config CC_IS_CLANG 28 def_bool $(success,test "$(cc-name)" = Clang) 29 30config CLANG_VERSION 31 int 32 default $(cc-version) if CC_IS_CLANG 33 default 0 34 35config AS_IS_GNU 36 def_bool $(success,test "$(as-name)" = GNU) 37 38config AS_IS_LLVM 39 def_bool $(success,test "$(as-name)" = LLVM) 40 41config 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 47config LD_IS_BFD 48 def_bool $(success,test "$(ld-name)" = BFD) 49 50config LD_VERSION 51 int 52 default $(ld-version) if LD_IS_BFD 53 default 0 54 55config LD_IS_LLD 56 def_bool $(success,test "$(ld-name)" = LLD) 57 58config LLD_VERSION 59 int 60 default $(ld-version) if LD_IS_LLD 61 default 0 62 63config 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 70config 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 81config RUSTC_LLVM_VERSION 82 int 83 default $(rustc-llvm-version) 84 85config ARCH_HAS_CC_CAN_LINK 86 bool 87 88config CC_CAN_LINK 89 bool 90 default ARCH_CC_CAN_LINK if ARCH_HAS_CC_CAN_LINK 91 default $(cc_can_link_user,$(m64-flag)) if 64BIT 92 default $(cc_can_link_user,$(m32-flag)) 93 94# Fixed in GCC 14, 13.3, 12.4 and 11.5 95# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113921 96config GCC_ASM_GOTO_OUTPUT_BROKEN 97 bool 98 depends on CC_IS_GCC 99 default y if GCC_VERSION < 110500 100 default y if GCC_VERSION >= 120000 && GCC_VERSION < 120400 101 default y if GCC_VERSION >= 130000 && GCC_VERSION < 130300 102 103config CC_HAS_ASM_GOTO_OUTPUT 104 def_bool y 105 depends on !GCC_ASM_GOTO_OUTPUT_BROKEN 106 # Detect basic support 107 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) 108 # Detect clang (< v17) scoped label issues 109 depends on $(success,echo 'void b(void **);void* c(void);int f(void){{asm goto(""::::l0);return 0;l0:return 1;}void *x __attribute__((cleanup(b)))=c();{asm goto(""::::l1);return 2;l1:return 3;}}' | $(CC) -x c - -c -o /dev/null) 110 111config CC_HAS_ASM_GOTO_TIED_OUTPUT 112 depends on CC_HAS_ASM_GOTO_OUTPUT 113 # Detect buggy gcc and clang, fixed in gcc-11 clang-14. 114 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) 115 116config TOOLS_SUPPORT_RELR 117 def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh) 118 119config CC_HAS_ASM_INLINE 120 def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null) 121 122config CC_HAS_ASSUME 123 bool 124 # clang needs to be at least 19.1.0 since the meaning of the assume 125 # attribute changed: 126 # https://github.com/llvm/llvm-project/commit/c44fa3e8a9a44c2e9a575768a3c185354b9f6c17 127 default y if CC_IS_CLANG && CLANG_VERSION >= 190100 128 # supported since gcc 13.1.0 129 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106654 130 default y if CC_IS_GCC && GCC_VERSION >= 130100 131 132config CC_HAS_NO_PROFILE_FN_ATTR 133 def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror) 134 135config CC_HAS_COUNTED_BY 136 bool 137 # clang needs to be at least 20.1.0 to avoid potential crashes 138 # when building structures that contain __counted_by 139 # https://github.com/ClangBuiltLinux/linux/issues/2114 140 # https://github.com/llvm/llvm-project/commit/160fb1121cdf703c3ef5e61fb26c5659eb581489 141 default y if CC_IS_CLANG && CLANG_VERSION >= 200100 142 # supported since gcc 15.1.0 143 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896 144 default y if CC_IS_GCC && GCC_VERSION >= 150100 145 146config CC_HAS_COUNTED_BY_PTR 147 bool 148 # supported since clang 22 149 default y if CC_IS_CLANG && CLANG_VERSION >= 220000 150 # supported since gcc 16.0.0 151 default y if CC_IS_GCC && GCC_VERSION >= 160000 152 153config CC_HAS_BROKEN_COUNTED_BY_REF 154 bool 155 # https://github.com/llvm/llvm-project/issues/182575 156 default y if CC_IS_CLANG && CLANG_VERSION < 220100 157 158config CC_HAS_MULTIDIMENSIONAL_NONSTRING 159 def_bool $(success,echo 'char tag[][4] __attribute__((__nonstring__)) = { };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror) 160 161config LD_CAN_USE_KEEP_IN_OVERLAY 162 # ld.lld prior to 21.0.0 did not support KEEP within an overlay description 163 # https://github.com/llvm/llvm-project/pull/130661 164 def_bool LD_IS_BFD || LLD_VERSION >= 210000 165 166config RUSTC_HAS_SLICE_AS_FLATTENED 167 def_bool RUSTC_VERSION >= 108000 168 169config RUSTC_HAS_COERCE_POINTEE 170 def_bool RUSTC_VERSION >= 108400 171 172config RUSTC_HAS_SPAN_FILE 173 def_bool RUSTC_VERSION >= 108800 174 175config RUSTC_HAS_UNNECESSARY_TRANSMUTES 176 def_bool RUSTC_VERSION >= 108800 177 178config RUSTC_HAS_FILE_WITH_NUL 179 def_bool RUSTC_VERSION >= 108900 180 181config RUSTC_HAS_FILE_AS_C_STR 182 def_bool RUSTC_VERSION >= 109100 183 184config PAHOLE_VERSION 185 int 186 default "$(PAHOLE_VERSION)" 187 188config CONSTRUCTORS 189 bool 190 191config IRQ_WORK 192 def_bool y if SMP 193 194config BUILDTIME_TABLE_SORT 195 bool 196 197config THREAD_INFO_IN_TASK 198 bool 199 help 200 Select this to move thread_info off the stack into task_struct. To 201 make this work, an arch will need to remove all thread_info fields 202 except flags and fix any runtime bugs. 203 204 One subtle change that will be needed is to use try_get_task_stack() 205 and put_task_stack() in save_thread_stack_tsk() and get_wchan(). 206 207menu "General setup" 208 209config BROKEN 210 bool 211 help 212 This option allows you to choose whether you want to try to 213 compile (and fix) old drivers that haven't been updated to 214 new infrastructure. 215 216config BROKEN_ON_SMP 217 bool 218 depends on BROKEN || !SMP 219 default y 220 221config INIT_ENV_ARG_LIMIT 222 int 223 default 32 if !UML 224 default 128 if UML 225 help 226 Maximum of each of the number of arguments and environment 227 variables passed to init from the kernel command line. 228 229config COMPILE_TEST 230 bool "Compile also drivers which will not load" 231 depends on HAS_IOMEM 232 help 233 Some drivers can be compiled on a different platform than they are 234 intended to be run on. Despite they cannot be loaded there (or even 235 when they load they cannot be used due to missing HW support), 236 developers still, opposing to distributors, might want to build such 237 drivers to compile-test them. 238 239 If you are a developer and want to build everything available, say Y 240 here. If you are a user/distributor, say N here to exclude useless 241 drivers to be distributed. 242 243config WERROR 244 bool "Compile the kernel with warnings as errors" 245 default COMPILE_TEST 246 help 247 A kernel build should not cause any compiler warnings, and this 248 enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags 249 to enforce that rule by default. Certain warnings from other tools 250 such as the linker may be upgraded to errors with this option as 251 well. 252 253 However, if you have a new (or very old) compiler or linker with odd 254 and unusual warnings, or you have some architecture with problems, 255 you may need to disable this config option in order to 256 successfully build the kernel. 257 258 If in doubt, say Y. 259 260config UAPI_HEADER_TEST 261 bool "Compile test UAPI headers" 262 depends on HEADERS_INSTALL 263 help 264 Compile test headers exported to user-space to ensure they are 265 self-contained, i.e. compilable as standalone units. 266 267 If you are a developer or tester and want to ensure the exported 268 headers are self-contained, say Y here. Otherwise, choose N. 269 270config LOCALVERSION 271 string "Local version - append to kernel release" 272 help 273 Append an extra string to the end of your kernel version. 274 This will show up when you type uname, for example. 275 The string you set here will be appended after the contents of 276 any files with a filename matching localversion* in your 277 object and source tree, in that order. Your total string can 278 be a maximum of 64 characters. 279 280config LOCALVERSION_AUTO 281 bool "Automatically append version information to the version string" 282 default y 283 depends on !COMPILE_TEST 284 help 285 This will try to automatically determine if the current tree is a 286 release tree by looking for git tags that belong to the current 287 top of tree revision. 288 289 A string of the format -gxxxxxxxx will be added to the localversion 290 if a git-based tree is found. The string generated by this will be 291 appended after any matching localversion* files, and after the value 292 set in CONFIG_LOCALVERSION. 293 294 (The actual string used here is the first 12 characters produced 295 by running the command: 296 297 $ git rev-parse --verify HEAD 298 299 which is done within the script "scripts/setlocalversion".) 300 301config BUILD_SALT 302 string "Build ID Salt" 303 default "" 304 help 305 The build ID is used to link binaries and their debug info. Setting 306 this option will use the value in the calculation of the build id. 307 This is mostly useful for distributions which want to ensure the 308 build is unique between builds. It's safe to leave the default. 309 310config HAVE_KERNEL_GZIP 311 bool 312 313config HAVE_KERNEL_BZIP2 314 bool 315 316config HAVE_KERNEL_LZMA 317 bool 318 319config HAVE_KERNEL_XZ 320 bool 321 322config HAVE_KERNEL_LZO 323 bool 324 325config HAVE_KERNEL_LZ4 326 bool 327 328config HAVE_KERNEL_ZSTD 329 bool 330 331config HAVE_KERNEL_UNCOMPRESSED 332 bool 333 334choice 335 prompt "Kernel compression mode" 336 default KERNEL_GZIP 337 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 338 help 339 The linux kernel is a kind of self-extracting executable. 340 Several compression algorithms are available, which differ 341 in efficiency, compression and decompression speed. 342 Compression speed is only relevant when building a kernel. 343 Decompression speed is relevant at each boot. 344 345 If you have any problems with bzip2 or lzma compressed 346 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 347 version of this functionality (bzip2 only), for 2.4, was 348 supplied by Christian Ludwig) 349 350 High compression options are mostly useful for users, who 351 are low on disk space (embedded systems), but for whom ram 352 size matters less. 353 354 If in doubt, select 'gzip' 355 356config KERNEL_GZIP 357 bool "Gzip" 358 depends on HAVE_KERNEL_GZIP 359 help 360 The old and tried gzip compression. It provides a good balance 361 between compression ratio and decompression speed. 362 363config KERNEL_BZIP2 364 bool "Bzip2" 365 depends on HAVE_KERNEL_BZIP2 366 help 367 Its compression ratio and speed is intermediate. 368 Decompression speed is slowest among the choices. The kernel 369 size is about 10% smaller with bzip2, in comparison to gzip. 370 Bzip2 uses a large amount of memory. For modern kernels you 371 will need at least 8MB RAM or more for booting. 372 373config KERNEL_LZMA 374 bool "LZMA" 375 depends on HAVE_KERNEL_LZMA 376 help 377 This compression algorithm's ratio is best. Decompression speed 378 is between gzip and bzip2. Compression is slowest. 379 The kernel size is about 33% smaller with LZMA in comparison to gzip. 380 381config KERNEL_XZ 382 bool "XZ" 383 depends on HAVE_KERNEL_XZ 384 help 385 XZ uses the LZMA2 algorithm and instruction set specific 386 BCJ filters which can improve compression ratio of executable 387 code. The size of the kernel is about 30% smaller with XZ in 388 comparison to gzip. On architectures for which there is a BCJ 389 filter (i386, x86_64, ARM, ARM64, RISC-V, big endian PowerPC, 390 and SPARC), XZ will create a few percent smaller kernel than 391 plain LZMA. 392 393 The speed is about the same as with LZMA: The decompression 394 speed of XZ is better than that of bzip2 but worse than gzip 395 and LZO. Compression is slow. 396 397config KERNEL_LZO 398 bool "LZO" 399 depends on HAVE_KERNEL_LZO 400 help 401 Its compression ratio is the poorest among the choices. The kernel 402 size is about 10% bigger than gzip; however its speed 403 (both compression and decompression) is the fastest. 404 405config KERNEL_LZ4 406 bool "LZ4" 407 depends on HAVE_KERNEL_LZ4 408 help 409 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. 410 A preliminary version of LZ4 de/compression tool is available at 411 <https://code.google.com/p/lz4/>. 412 413 Its compression ratio is worse than LZO. The size of the kernel 414 is about 8% bigger than LZO. But the decompression speed is 415 faster than LZO. 416 417config KERNEL_ZSTD 418 bool "ZSTD" 419 depends on HAVE_KERNEL_ZSTD 420 help 421 ZSTD is a compression algorithm targeting intermediate compression 422 with fast decompression speed. It will compress better than GZIP and 423 decompress around the same speed as LZO, but slower than LZ4. You 424 will need at least 192 KB RAM or more for booting. The zstd command 425 line tool is required for compression. 426 427config KERNEL_UNCOMPRESSED 428 bool "None" 429 depends on HAVE_KERNEL_UNCOMPRESSED 430 help 431 Produce uncompressed kernel image. This option is usually not what 432 you want. It is useful for debugging the kernel in slow simulation 433 environments, where decompressing and moving the kernel is awfully 434 slow. This option allows early boot code to skip the decompressor 435 and jump right at uncompressed kernel image. 436 437endchoice 438 439config DEFAULT_INIT 440 string "Default init path" 441 default "" 442 help 443 This option determines the default init for the system if no init= 444 option is passed on the kernel command line. If the requested path is 445 not present, we will still then move on to attempting further 446 locations (e.g. /sbin/init, etc). If this is empty, we will just use 447 the fallback list when init= is not passed. 448 449config DEFAULT_HOSTNAME 450 string "Default hostname" 451 default "(none)" 452 help 453 This option determines the default system hostname before userspace 454 calls sethostname(2). The kernel traditionally uses "(none)" here, 455 but you may wish to use a different default here to make a minimal 456 system more usable with less configuration. 457 458config SYSVIPC 459 bool "System V IPC" 460 help 461 Inter Process Communication is a suite of library functions and 462 system calls which let processes (running programs) synchronize and 463 exchange information. It is generally considered to be a good thing, 464 and some programs won't run unless you say Y here. In particular, if 465 you want to run the DOS emulator dosemu under Linux (read the 466 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 467 you'll need to say Y here. 468 469 You can find documentation about IPC with "info ipc" and also in 470 section 6.4 of the Linux Programmer's Guide, available from 471 <http://www.tldp.org/guides.html>. 472 473config SYSVIPC_SYSCTL 474 bool 475 depends on SYSVIPC 476 depends on SYSCTL 477 default y 478 479config SYSVIPC_COMPAT 480 def_bool y 481 depends on COMPAT && SYSVIPC 482 483config POSIX_MQUEUE 484 bool "POSIX Message Queues" 485 depends on NET 486 help 487 POSIX variant of message queues is a part of IPC. In POSIX message 488 queues every message has a priority which decides about succession 489 of receiving it by a process. If you want to compile and run 490 programs written e.g. for Solaris with use of its POSIX message 491 queues (functions mq_*) say Y here. 492 493 POSIX message queues are visible as a filesystem called 'mqueue' 494 and can be mounted somewhere if you want to do filesystem 495 operations on message queues. 496 497 If unsure, say Y. 498 499config POSIX_MQUEUE_SYSCTL 500 bool 501 depends on POSIX_MQUEUE 502 depends on SYSCTL 503 default y 504 505config WATCH_QUEUE 506 bool "General notification queue" 507 default n 508 help 509 510 This is a general notification queue for the kernel to pass events to 511 userspace by splicing them into pipes. It can be used in conjunction 512 with watches for key/keyring change notifications and device 513 notifications. 514 515 See Documentation/core-api/watch_queue.rst 516 517config CROSS_MEMORY_ATTACH 518 bool "Enable process_vm_readv/writev syscalls" 519 depends on MMU 520 default y 521 help 522 Enabling this option adds the system calls process_vm_readv and 523 process_vm_writev which allow a process with the correct privileges 524 to directly read from or write to another process' address space. 525 See the man page for more details. 526 527config AUDIT 528 bool "Auditing support" 529 depends on NET 530 help 531 Enable auditing infrastructure that can be used with another 532 kernel subsystem, such as SELinux (which requires this for 533 logging of avc messages output). System call auditing is included 534 on architectures which support it. 535 536config HAVE_ARCH_AUDITSYSCALL 537 bool 538 539config AUDITSYSCALL 540 def_bool y 541 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL 542 select FSNOTIFY 543 544source "kernel/irq/Kconfig" 545source "kernel/time/Kconfig" 546source "kernel/bpf/Kconfig" 547source "kernel/Kconfig.preempt" 548 549menu "CPU/Task time and stats accounting" 550 551config VIRT_CPU_ACCOUNTING 552 bool 553 554choice 555 prompt "Cputime accounting" 556 default TICK_CPU_ACCOUNTING 557 558# Kind of a stub config for the pure tick based cputime accounting 559config TICK_CPU_ACCOUNTING 560 bool "Simple tick based cputime accounting" 561 depends on !S390 && !NO_HZ_FULL 562 help 563 This is the basic tick based cputime accounting that maintains 564 statistics about user, system and idle time spent on per jiffies 565 granularity. 566 567 If unsure, say Y. 568 569config VIRT_CPU_ACCOUNTING_NATIVE 570 bool "Deterministic task and CPU time accounting" 571 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL 572 select VIRT_CPU_ACCOUNTING 573 help 574 Select this option to enable more accurate task and CPU time 575 accounting. This is done by reading a CPU counter on each 576 kernel entry and exit and on transitions within the kernel 577 between system, softirq and hardirq state, so there is a 578 small performance impact. In the case of s390 or IBM POWER > 5, 579 this also enables accounting of stolen time on logically-partitioned 580 systems. 581 582config VIRT_CPU_ACCOUNTING_GEN 583 bool "Full dynticks CPU time accounting" 584 depends on HAVE_CONTEXT_TRACKING_USER 585 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN 586 depends on GENERIC_CLOCKEVENTS 587 select VIRT_CPU_ACCOUNTING 588 select CONTEXT_TRACKING_USER 589 help 590 Select this option to enable task and CPU time accounting on full 591 dynticks systems. This accounting is implemented by watching every 592 kernel-user boundaries using the context tracking subsystem. 593 The accounting is thus performed at the expense of some significant 594 overhead. 595 596 For now this is only useful if you are working on the full 597 dynticks subsystem development. 598 599 If unsure, say N. 600 601endchoice 602 603config IRQ_TIME_ACCOUNTING 604 bool "Fine granularity task level IRQ time accounting" 605 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE 606 help 607 Select this option to enable fine granularity task irq time 608 accounting. This is done by reading a timestamp on each 609 transitions between softirq and hardirq state, so there can be a 610 small performance impact. 611 612 If in doubt, say N here. 613 614config HAVE_SCHED_AVG_IRQ 615 def_bool y 616 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING 617 depends on SMP 618 619config SCHED_HW_PRESSURE 620 bool 621 default y if ARM && ARM_CPU_TOPOLOGY 622 default y if ARM64 623 depends on SMP 624 depends on CPU_FREQ_THERMAL 625 help 626 Select this option to enable HW pressure accounting in the 627 scheduler. HW pressure is the value conveyed to the scheduler 628 that reflects the reduction in CPU compute capacity resulted from 629 HW throttling. HW throttling occurs when the performance of 630 a CPU is capped due to high operating temperatures as an example. 631 632 If selected, the scheduler will be able to balance tasks accordingly, 633 i.e. put less load on throttled CPUs than on non/less throttled ones. 634 635 This requires the architecture to implement 636 arch_update_hw_pressure() and arch_scale_thermal_pressure(). 637 638config BSD_PROCESS_ACCT 639 bool "BSD Process Accounting (DEPRECATED)" 640 depends on MULTIUSER 641 default n 642 help 643 If you say Y here, a user level program will be able to instruct the 644 kernel (via a special system call) to write process accounting 645 information to a file: whenever a process exits, information about 646 that process will be appended to the file by the kernel. The 647 information includes things such as creation time, owning user, 648 command name, memory usage, controlling terminal etc. (the complete 649 list is in the struct acct in <file:include/linux/acct.h>). It is 650 up to the user level program to do useful things with this 651 information. This mechanism is antiquated and has significant 652 scalability issues. You probably want to use eBPF instead. Say 653 N unless you really need this. 654 655config BSD_PROCESS_ACCT_V3 656 bool "BSD Process Accounting version 3 file format" 657 depends on BSD_PROCESS_ACCT 658 default n 659 help 660 If you say Y here, the process accounting information is written 661 in a new file format that also logs the process IDs of each 662 process and its parent. Note that this file format is incompatible 663 with previous v0/v1/v2 file formats, so you will need updated tools 664 for processing it. A preliminary version of these tools is available 665 at <http://www.gnu.org/software/acct/>. 666 667config TASKSTATS 668 bool "Export task/process statistics through netlink" 669 depends on NET 670 depends on MULTIUSER 671 default n 672 help 673 Export selected statistics for tasks/processes through the 674 generic netlink interface. Unlike BSD process accounting, the 675 statistics are available during the lifetime of tasks/processes as 676 responses to commands. Like BSD accounting, they are sent to user 677 space on task exit. 678 679 Say N if unsure. 680 681config TASK_DELAY_ACCT 682 bool "Enable per-task delay accounting" 683 depends on TASKSTATS 684 select SCHED_INFO 685 help 686 Collect information on time spent by a task waiting for system 687 resources like cpu, synchronous block I/O completion and swapping 688 in pages. Such statistics can help in setting a task's priorities 689 relative to other tasks for cpu, io, rss limits etc. 690 691 Say N if unsure. 692 693config TASK_XACCT 694 bool "Enable extended accounting over taskstats" 695 depends on TASKSTATS 696 help 697 Collect extended task accounting data and send the data 698 to userland for processing over the taskstats interface. 699 700 Say N if unsure. 701 702config TASK_IO_ACCOUNTING 703 bool "Enable per-task storage I/O accounting" 704 depends on TASK_XACCT 705 help 706 Collect information on the number of bytes of storage I/O which this 707 task has caused. 708 709 Say N if unsure. 710 711config PSI 712 bool "Pressure stall information tracking" 713 select KERNFS 714 help 715 Collect metrics that indicate how overcommitted the CPU, memory, 716 and IO capacity are in the system. 717 718 If you say Y here, the kernel will create /proc/pressure/ with the 719 pressure statistics files cpu, memory, and io. These will indicate 720 the share of walltime in which some or all tasks in the system are 721 delayed due to contention of the respective resource. 722 723 In kernels with cgroup support, cgroups (cgroup2 only) will 724 have cpu.pressure, memory.pressure, and io.pressure files, 725 which aggregate pressure stalls for the grouped tasks only. 726 727 For more details see Documentation/accounting/psi.rst. 728 729 Say N if unsure. 730 731config PSI_DEFAULT_DISABLED 732 bool "Require boot parameter to enable pressure stall information tracking" 733 default n 734 depends on PSI 735 help 736 If set, pressure stall information tracking will be disabled 737 per default but can be enabled through passing psi=1 on the 738 kernel commandline during boot. 739 740 This feature adds some code to the task wakeup and sleep 741 paths of the scheduler. The overhead is too low to affect 742 common scheduling-intense workloads in practice (such as 743 webservers, memcache), but it does show up in artificial 744 scheduler stress tests, such as hackbench. 745 746 If you are paranoid and not sure what the kernel will be 747 used for, say Y. 748 749 Say N if unsure. 750 751endmenu # "CPU/Task time and stats accounting" 752 753config CPU_ISOLATION 754 bool "CPU isolation" 755 depends on SMP 756 default y 757 help 758 Make sure that CPUs running critical tasks are not disturbed by 759 any source of "noise" such as unbound workqueues, timers, kthreads... 760 Unbound jobs get offloaded to housekeeping CPUs. This is driven by 761 the "isolcpus=" boot parameter. 762 763 Say Y if unsure. 764 765source "kernel/rcu/Kconfig" 766 767config IKCONFIG 768 tristate "Kernel .config support" 769 help 770 This option enables the complete Linux kernel ".config" file 771 contents to be saved in the kernel. It provides documentation 772 of which kernel options are used in a running kernel or in an 773 on-disk kernel. This information can be extracted from the kernel 774 image file with the script scripts/extract-ikconfig and used as 775 input to rebuild the current kernel or to build another kernel. 776 It can also be extracted from a running kernel by reading 777 /proc/config.gz if enabled (below). 778 779config IKCONFIG_PROC 780 bool "Enable access to .config through /proc/config.gz" 781 depends on IKCONFIG && PROC_FS 782 help 783 This option enables access to the kernel configuration file 784 through /proc/config.gz. 785 786config IKHEADERS 787 tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz" 788 depends on SYSFS 789 help 790 This option enables access to the in-kernel headers that are generated during 791 the build process. These can be used to build eBPF tracing programs, 792 or similar programs. If you build the headers as a module, a module called 793 kheaders.ko is built which can be loaded on-demand to get access to headers. 794 795config LOG_BUF_SHIFT 796 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 797 range 12 25 798 default 17 799 depends on PRINTK 800 help 801 Select the minimal kernel log buffer size as a power of 2. 802 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config 803 parameter, see below. Any higher size also might be forced 804 by "log_buf_len" boot parameter. 805 806 Examples: 807 17 => 128 KB 808 16 => 64 KB 809 15 => 32 KB 810 14 => 16 KB 811 13 => 8 KB 812 12 => 4 KB 813 814config LOG_CPU_MAX_BUF_SHIFT 815 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" 816 depends on SMP 817 range 0 21 818 default 0 if BASE_SMALL 819 default 12 820 depends on PRINTK 821 help 822 This option allows to increase the default ring buffer size 823 according to the number of CPUs. The value defines the contribution 824 of each CPU as a power of 2. The used space is typically only few 825 lines however it might be much more when problems are reported, 826 e.g. backtraces. 827 828 The increased size means that a new buffer has to be allocated and 829 the original static one is unused. It makes sense only on systems 830 with more CPUs. Therefore this value is used only when the sum of 831 contributions is greater than the half of the default kernel ring 832 buffer as defined by LOG_BUF_SHIFT. The default values are set 833 so that more than 16 CPUs are needed to trigger the allocation. 834 835 Also this option is ignored when "log_buf_len" kernel parameter is 836 used as it forces an exact (power of two) size of the ring buffer. 837 838 The number of possible CPUs is used for this computation ignoring 839 hotplugging making the computation optimal for the worst case 840 scenario while allowing a simple algorithm to be used from bootup. 841 842 Examples shift values and their meaning: 843 17 => 128 KB for each CPU 844 16 => 64 KB for each CPU 845 15 => 32 KB for each CPU 846 14 => 16 KB for each CPU 847 13 => 8 KB for each CPU 848 12 => 4 KB for each CPU 849 850config PRINTK_INDEX 851 bool "Printk indexing debugfs interface" 852 depends on PRINTK && DEBUG_FS 853 help 854 Add support for indexing of all printk formats known at compile time 855 at <debugfs>/printk/index/<module>. 856 857 This can be used as part of maintaining daemons which monitor 858 /dev/kmsg, as it permits auditing the printk formats present in a 859 kernel, allowing detection of cases where monitored printks are 860 changed or no longer present. 861 862 There is no additional runtime cost to printk with this enabled. 863 864# 865# Architectures with an unreliable sched_clock() should select this: 866# 867config HAVE_UNSTABLE_SCHED_CLOCK 868 bool 869 870config GENERIC_SCHED_CLOCK 871 bool 872 873menu "Scheduler features" 874 875config UCLAMP_TASK 876 bool "Enable utilization clamping for RT/FAIR tasks" 877 depends on CPU_FREQ_GOV_SCHEDUTIL 878 help 879 This feature enables the scheduler to track the clamped utilization 880 of each CPU based on RUNNABLE tasks scheduled on that CPU. 881 882 With this option, the user can specify the min and max CPU 883 utilization allowed for RUNNABLE tasks. The max utilization defines 884 the maximum frequency a task should use while the min utilization 885 defines the minimum frequency it should use. 886 887 Both min and max utilization clamp values are hints to the scheduler, 888 aiming at improving its frequency selection policy, but they do not 889 enforce or grant any specific bandwidth for tasks. 890 891 If in doubt, say N. 892 893config UCLAMP_BUCKETS_COUNT 894 int "Number of supported utilization clamp buckets" 895 range 5 20 896 default 5 897 depends on UCLAMP_TASK 898 help 899 Defines the number of clamp buckets to use. The range of each bucket 900 will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the 901 number of clamp buckets the finer their granularity and the higher 902 the precision of clamping aggregation and tracking at run-time. 903 904 For example, with the minimum configuration value we will have 5 905 clamp buckets tracking 20% utilization each. A 25% boosted tasks will 906 be refcounted in the [20..39]% bucket and will set the bucket clamp 907 effective value to 25%. 908 If a second 30% boosted task should be co-scheduled on the same CPU, 909 that task will be refcounted in the same bucket of the first task and 910 it will boost the bucket clamp effective value to 30%. 911 The clamp effective value of a bucket is reset to its nominal value 912 (20% in the example above) when there are no more tasks refcounted in 913 that bucket. 914 915 An additional boost/capping margin can be added to some tasks. In the 916 example above the 25% task will be boosted to 30% until it exits the 917 CPU. If that should be considered not acceptable on certain systems, 918 it's always possible to reduce the margin by increasing the number of 919 clamp buckets to trade off used memory for run-time tracking 920 precision. 921 922 If in doubt, use the default value. 923 924config SCHED_PROXY_EXEC 925 bool "Proxy Execution" 926 # Avoid some build failures w/ PREEMPT_RT until it can be fixed 927 depends on !PREEMPT_RT 928 # Need to investigate how to inform sched_ext of split contexts 929 depends on !SCHED_CLASS_EXT 930 # Not particularly useful until we get to multi-rq proxying 931 depends on EXPERT 932 help 933 This option enables proxy execution, a mechanism for mutex-owning 934 tasks to inherit the scheduling context of higher priority waiters. 935 936endmenu 937 938# 939# For architectures that want to enable the support for NUMA-affine scheduler 940# balancing logic: 941# 942config ARCH_SUPPORTS_NUMA_BALANCING 943 bool 944 945# 946# For architectures that prefer to flush all TLBs after a number of pages 947# are unmapped instead of sending one IPI per page to flush. The architecture 948# must provide guarantees on what happens if a clean TLB cache entry is 949# written after the unmap. Details are in mm/rmap.c near the check for 950# should_defer_flush. The architecture should also consider if the full flush 951# and the refill costs are offset by the savings of sending fewer IPIs. 952config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 953 bool 954 955config CC_HAS_INT128 956 def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT 957 958config CC_IMPLICIT_FALLTHROUGH 959 string 960 default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) 961 default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) 962 963# Currently, disable gcc-10+ array-bounds globally. 964# It's still broken in gcc-13, so no upper bound yet. 965config GCC10_NO_ARRAY_BOUNDS 966 def_bool y 967 968config CC_NO_ARRAY_BOUNDS 969 bool 970 default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC10_NO_ARRAY_BOUNDS 971 972# Currently, disable -Wstringop-overflow for GCC globally. 973config GCC_NO_STRINGOP_OVERFLOW 974 def_bool y 975 976config CC_NO_STRINGOP_OVERFLOW 977 bool 978 default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW 979 980config CC_STRINGOP_OVERFLOW 981 bool 982 default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW 983 984# 985# For architectures that know their GCC __int128 support is sound 986# 987config ARCH_SUPPORTS_INT128 988 bool 989 990# For architectures that (ab)use NUMA to represent different memory regions 991# all cpu-local but of different latencies, such as SuperH. 992# 993config ARCH_WANT_NUMA_VARIABLE_LOCALITY 994 bool 995 996config NUMA_BALANCING 997 bool "Memory placement aware NUMA scheduler" 998 depends on ARCH_SUPPORTS_NUMA_BALANCING 999 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY 1000 depends on SMP && NUMA && MIGRATION && !PREEMPT_RT 1001 help 1002 This option adds support for automatic NUMA aware memory/task placement. 1003 The mechanism is quite primitive and is based on migrating memory when 1004 it has references to the node the task is running on. 1005 1006 This system will be inactive on UMA systems. 1007 1008config NUMA_BALANCING_DEFAULT_ENABLED 1009 bool "Automatically enable NUMA aware memory/task placement" 1010 default y 1011 depends on NUMA_BALANCING 1012 help 1013 If set, automatic NUMA balancing will be enabled if running on a NUMA 1014 machine. 1015 1016config SLAB_OBJ_EXT 1017 bool 1018 1019menuconfig CGROUPS 1020 bool "Control Group support" 1021 select KERNFS 1022 help 1023 This option adds support for grouping sets of processes together, for 1024 use with process control subsystems such as Cpusets, CFS, memory 1025 controls or device isolation. 1026 See 1027 - Documentation/scheduler/sched-design-CFS.rst (CFS) 1028 - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation 1029 and resource control) 1030 1031 Say N if unsure. 1032 1033if CGROUPS 1034 1035config PAGE_COUNTER 1036 bool 1037 1038config CGROUP_FAVOR_DYNMODS 1039 bool "Favor dynamic modification latency reduction by default" 1040 help 1041 This option enables the "favordynmods" mount option by default 1042 which reduces the latencies of dynamic cgroup modifications such 1043 as task migrations and controller on/offs at the cost of making 1044 hot path operations such as forks and exits more expensive. 1045 1046 Say N if unsure. 1047 1048config MEMCG 1049 bool "Memory controller" 1050 select PAGE_COUNTER 1051 select EVENTFD 1052 select SLAB_OBJ_EXT 1053 select VM_EVENT_COUNTERS 1054 help 1055 Provides control over the memory footprint of tasks in a cgroup. 1056 1057config MEMCG_NMI_UNSAFE 1058 bool 1059 depends on MEMCG 1060 depends on HAVE_NMI 1061 depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && !ARCH_HAVE_NMI_SAFE_CMPXCHG 1062 default y 1063 1064config MEMCG_NMI_SAFETY_REQUIRES_ATOMIC 1065 bool 1066 depends on MEMCG 1067 depends on HAVE_NMI 1068 depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && ARCH_HAVE_NMI_SAFE_CMPXCHG 1069 default y 1070 1071config MEMCG_V1 1072 bool "Legacy cgroup v1 memory controller" 1073 depends on MEMCG 1074 default n 1075 help 1076 Legacy cgroup v1 memory controller which has been deprecated by 1077 cgroup v2 implementation. The v1 is there for legacy applications 1078 which haven't migrated to the new cgroup v2 interface yet. If you 1079 do not have any such application then you are completely fine leaving 1080 this option disabled. 1081 1082 Please note that feature set of the legacy memory controller is likely 1083 going to shrink due to deprecation process. New deployments with v1 1084 controller are highly discouraged. 1085 1086 Say N if unsure. 1087 1088config BLK_CGROUP 1089 bool "IO controller" 1090 depends on BLOCK 1091 default n 1092 help 1093 Generic block IO controller cgroup interface. This is the common 1094 cgroup interface which should be used by various IO controlling 1095 policies. 1096 1097 Currently, CFQ IO scheduler uses it to recognize task groups and 1098 control disk bandwidth allocation (proportional time slice allocation) 1099 to such task groups. It is also used by bio throttling logic in 1100 block layer to implement upper limit in IO rates on a device. 1101 1102 This option only enables generic Block IO controller infrastructure. 1103 One needs to also enable actual IO controlling logic/policy. For 1104 enabling proportional weight division of disk bandwidth in CFQ, set 1105 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 1106 CONFIG_BLK_DEV_THROTTLING=y. 1107 1108 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information. 1109 1110config CGROUP_WRITEBACK 1111 bool 1112 depends on MEMCG && BLK_CGROUP 1113 default y 1114 1115menuconfig CGROUP_SCHED 1116 bool "CPU controller" 1117 default n 1118 help 1119 This feature lets CPU scheduler recognize task groups and control CPU 1120 bandwidth allocation to such task groups. It uses cgroups to group 1121 tasks. 1122 1123if CGROUP_SCHED 1124config GROUP_SCHED_WEIGHT 1125 def_bool n 1126 1127config GROUP_SCHED_BANDWIDTH 1128 def_bool n 1129 1130config FAIR_GROUP_SCHED 1131 bool "Group scheduling for SCHED_OTHER" 1132 depends on CGROUP_SCHED 1133 select GROUP_SCHED_WEIGHT 1134 default CGROUP_SCHED 1135 1136config CFS_BANDWIDTH 1137 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 1138 depends on FAIR_GROUP_SCHED 1139 select GROUP_SCHED_BANDWIDTH 1140 default n 1141 help 1142 This option allows users to define CPU bandwidth rates (limits) for 1143 tasks running within the fair group scheduler. Groups with no limit 1144 set are considered to be unconstrained and will run with no 1145 restriction. 1146 See Documentation/scheduler/sched-bwc.rst for more information. 1147 1148config RT_GROUP_SCHED 1149 bool "Group scheduling for SCHED_RR/FIFO" 1150 depends on CGROUP_SCHED 1151 default n 1152 help 1153 This feature lets you explicitly allocate real CPU bandwidth 1154 to task groups. If enabled, it will also make it impossible to 1155 schedule realtime tasks for non-root users until you allocate 1156 realtime bandwidth for them. 1157 See Documentation/scheduler/sched-rt-group.rst for more information. 1158 1159config RT_GROUP_SCHED_DEFAULT_DISABLED 1160 bool "Require boot parameter to enable group scheduling for SCHED_RR/FIFO" 1161 depends on RT_GROUP_SCHED 1162 default n 1163 help 1164 When set, the RT group scheduling is disabled by default. The option 1165 is in inverted form so that mere RT_GROUP_SCHED enables the group 1166 scheduling. 1167 1168 Say N if unsure. 1169 1170config EXT_GROUP_SCHED 1171 bool 1172 depends on SCHED_CLASS_EXT && CGROUP_SCHED 1173 select GROUP_SCHED_WEIGHT 1174 select GROUP_SCHED_BANDWIDTH 1175 default y 1176 1177endif #CGROUP_SCHED 1178 1179config EXT_SUB_SCHED 1180 def_bool y 1181 depends on SCHED_CLASS_EXT 1182 1183config SCHED_MM_CID 1184 def_bool y 1185 depends on SMP && RSEQ 1186 1187config UCLAMP_TASK_GROUP 1188 bool "Utilization clamping per group of tasks" 1189 depends on CGROUP_SCHED 1190 depends on UCLAMP_TASK 1191 default n 1192 help 1193 This feature enables the scheduler to track the clamped utilization 1194 of each CPU based on RUNNABLE tasks currently scheduled on that CPU. 1195 1196 When this option is enabled, the user can specify a min and max 1197 CPU bandwidth which is allowed for each single task in a group. 1198 The max bandwidth allows to clamp the maximum frequency a task 1199 can use, while the min bandwidth allows to define a minimum 1200 frequency a task will always use. 1201 1202 When task group based utilization clamping is enabled, an eventually 1203 specified task-specific clamp value is constrained by the cgroup 1204 specified clamp value. Both minimum and maximum task clamping cannot 1205 be bigger than the corresponding clamping defined at task group level. 1206 1207 If in doubt, say N. 1208 1209config CGROUP_PIDS 1210 bool "PIDs controller" 1211 help 1212 Provides enforcement of process number limits in the scope of a 1213 cgroup. Any attempt to fork more processes than is allowed in the 1214 cgroup will fail. PIDs are fundamentally a global resource because it 1215 is fairly trivial to reach PID exhaustion before you reach even a 1216 conservative kmemcg limit. As a result, it is possible to grind a 1217 system to halt without being limited by other cgroup policies. The 1218 PIDs controller is designed to stop this from happening. 1219 1220 It should be noted that organisational operations (such as attaching 1221 to a cgroup hierarchy) will *not* be blocked by the PIDs controller, 1222 since the PIDs limit only affects a process's ability to fork, not to 1223 attach to a cgroup. 1224 1225config CGROUP_RDMA 1226 bool "RDMA controller" 1227 help 1228 Provides enforcement of RDMA resources defined by IB stack. 1229 It is fairly easy for consumers to exhaust RDMA resources, which 1230 can result into resource unavailability to other consumers. 1231 RDMA controller is designed to stop this from happening. 1232 Attaching processes with active RDMA resources to the cgroup 1233 hierarchy is allowed even if can cross the hierarchy's limit. 1234 1235config CGROUP_DMEM 1236 bool "Device memory controller (DMEM)" 1237 select PAGE_COUNTER 1238 help 1239 The DMEM controller allows compatible devices to restrict device 1240 memory usage based on the cgroup hierarchy. 1241 1242 As an example, it allows you to restrict VRAM usage for applications 1243 in the DRM subsystem. 1244 1245config CGROUP_FREEZER 1246 bool "Freezer controller" 1247 help 1248 Provides a way to freeze and unfreeze all tasks in a 1249 cgroup. 1250 1251 This option affects the ORIGINAL cgroup interface. The cgroup2 memory 1252 controller includes important in-kernel memory consumers per default. 1253 1254 If you're using cgroup2, say N. 1255 1256config CGROUP_HUGETLB 1257 bool "HugeTLB controller" 1258 depends on HUGETLB_PAGE 1259 select PAGE_COUNTER 1260 default n 1261 help 1262 Provides a cgroup controller for HugeTLB pages. 1263 When you enable this, you can put a per cgroup limit on HugeTLB usage. 1264 The limit is enforced during page fault. Since HugeTLB doesn't 1265 support page reclaim, enforcing the limit at page fault time implies 1266 that, the application will get SIGBUS signal if it tries to access 1267 HugeTLB pages beyond its limit. This requires the application to know 1268 beforehand how much HugeTLB pages it would require for its use. The 1269 control group is tracked in the third page lru pointer. This means 1270 that we cannot use the controller with huge page less than 3 pages. 1271 1272config CPUSETS 1273 bool "Cpuset controller" 1274 depends on SMP 1275 select UNION_FIND 1276 select CPU_ISOLATION 1277 help 1278 This option will let you create and manage CPUSETs which 1279 allow dynamically partitioning a system into sets of CPUs and 1280 Memory Nodes and assigning tasks to run only within those sets. 1281 This is primarily useful on large SMP or NUMA systems. 1282 1283 Say N if unsure. 1284 1285config CPUSETS_V1 1286 bool "Legacy cgroup v1 cpusets controller" 1287 depends on CPUSETS 1288 default n 1289 help 1290 Legacy cgroup v1 cpusets controller which has been deprecated by 1291 cgroup v2 implementation. The v1 is there for legacy applications 1292 which haven't migrated to the new cgroup v2 interface yet. Legacy 1293 interface includes cpuset filesystem and /proc/<pid>/cpuset. If you 1294 do not have any such application then you are completely fine leaving 1295 this option disabled. 1296 1297 Say N if unsure. 1298 1299config PROC_PID_CPUSET 1300 bool "Include legacy /proc/<pid>/cpuset file" 1301 depends on CPUSETS_V1 1302 default y 1303 1304config CGROUP_DEVICE 1305 bool "Device controller" 1306 help 1307 Provides a cgroup controller implementing whitelists for 1308 devices which a process in the cgroup can mknod or open. 1309 1310config CGROUP_CPUACCT 1311 bool "Simple CPU accounting controller" 1312 help 1313 Provides a simple controller for monitoring the 1314 total CPU consumed by the tasks in a cgroup. 1315 1316config CGROUP_PERF 1317 bool "Perf controller" 1318 depends on PERF_EVENTS 1319 help 1320 This option extends the perf per-cpu mode to restrict monitoring 1321 to threads which belong to the cgroup specified and run on the 1322 designated cpu. Or this can be used to have cgroup ID in samples 1323 so that it can monitor performance events among cgroups. 1324 1325 Say N if unsure. 1326 1327config CGROUP_BPF 1328 bool "Support for eBPF programs attached to cgroups" 1329 depends on BPF_SYSCALL 1330 select SOCK_CGROUP_DATA 1331 help 1332 Allow attaching eBPF programs to a cgroup using the bpf(2) 1333 syscall command BPF_PROG_ATTACH. 1334 1335 In which context these programs are accessed depends on the type 1336 of attachment. For instance, programs that are attached using 1337 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of 1338 inet sockets. 1339 1340config CGROUP_MISC 1341 bool "Misc resource controller" 1342 default n 1343 help 1344 Provides a controller for miscellaneous resources on a host. 1345 1346 Miscellaneous scalar resources are the resources on the host system 1347 which cannot be abstracted like the other cgroups. This controller 1348 tracks and limits the miscellaneous resources used by a process 1349 attached to a cgroup hierarchy. 1350 1351 For more information, please check misc cgroup section in 1352 /Documentation/admin-guide/cgroup-v2.rst. 1353 1354config CGROUP_DEBUG 1355 bool "Debug controller" 1356 default n 1357 depends on DEBUG_KERNEL 1358 help 1359 This option enables a simple controller that exports 1360 debugging information about the cgroups framework. This 1361 controller is for control cgroup debugging only. Its 1362 interfaces are not stable. 1363 1364 Say N. 1365 1366config SOCK_CGROUP_DATA 1367 bool 1368 default n 1369 1370endif # CGROUPS 1371 1372menuconfig NAMESPACES 1373 bool "Namespaces support" if EXPERT 1374 depends on MULTIUSER 1375 default !EXPERT 1376 help 1377 Provides the way to make tasks work with different objects using 1378 the same id. For example same IPC id may refer to different objects 1379 or same user id or pid may refer to different tasks when used in 1380 different namespaces. 1381 1382if NAMESPACES 1383 1384config UTS_NS 1385 bool "UTS namespace" 1386 default y 1387 help 1388 In this namespace tasks see different info provided with the 1389 uname() system call 1390 1391config TIME_NS 1392 bool "TIME namespace" 1393 depends on GENERIC_GETTIMEOFDAY 1394 default y 1395 help 1396 In this namespace boottime and monotonic clocks can be set. 1397 The time will keep going with the same pace. 1398 1399config IPC_NS 1400 bool "IPC namespace" 1401 depends on (SYSVIPC || POSIX_MQUEUE) 1402 default y 1403 help 1404 In this namespace tasks work with IPC ids which correspond to 1405 different IPC objects in different namespaces. 1406 1407config USER_NS 1408 bool "User namespace" 1409 default n 1410 help 1411 This allows containers, i.e. vservers, to use user namespaces 1412 to provide different user info for different servers. 1413 1414 When user namespaces are enabled in the kernel it is 1415 recommended that the MEMCG option also be enabled and that 1416 user-space use the memory control groups to limit the amount 1417 of memory a memory unprivileged users can use. 1418 1419 If unsure, say N. 1420 1421config PID_NS 1422 bool "PID Namespaces" 1423 default y 1424 help 1425 Support process id namespaces. This allows having multiple 1426 processes with the same pid as long as they are in different 1427 pid namespaces. This is a building block of containers. 1428 1429config NET_NS 1430 bool "Network namespace" 1431 depends on NET 1432 default y 1433 help 1434 Allow user space to create what appear to be multiple instances 1435 of the network stack. 1436 1437endif # NAMESPACES 1438 1439config CHECKPOINT_RESTORE 1440 bool "Checkpoint/restore support" 1441 depends on PROC_FS 1442 select PROC_CHILDREN 1443 select KCMP 1444 default n 1445 help 1446 Enables additional kernel features in a sake of checkpoint/restore. 1447 In particular it adds auxiliary prctl codes to setup process text, 1448 data and heap segment sizes, and a few additional /proc filesystem 1449 entries. 1450 1451 If unsure, say N here. 1452 1453config SCHED_AUTOGROUP 1454 bool "Automatic process group scheduling" 1455 select CGROUPS 1456 select CGROUP_SCHED 1457 select FAIR_GROUP_SCHED 1458 help 1459 This option optimizes the scheduler for common desktop workloads by 1460 automatically creating and populating task groups. This separation 1461 of workloads isolates aggressive CPU burners (like build jobs) from 1462 desktop applications. Task group autogeneration is currently based 1463 upon task session. 1464 1465config RELAY 1466 bool "Kernel->user space relay support (formerly relayfs)" 1467 select IRQ_WORK 1468 help 1469 This option enables support for relay interface support in 1470 certain file systems (such as debugfs). 1471 It is designed to provide an efficient mechanism for tools and 1472 facilities to relay large amounts of data from kernel space to 1473 user space. 1474 1475 If unsure, say N. 1476 1477config BLK_DEV_INITRD 1478 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1479 help 1480 The initial RAM filesystem is a ramfs which is loaded by the 1481 boot loader (loadlin or lilo) and that is mounted as root 1482 before the normal boot procedure. It is typically used to 1483 load modules needed to mount the "real" root file system, 1484 etc. See <file:Documentation/admin-guide/initrd.rst> for details. 1485 1486 If RAM disk support (BLK_DEV_RAM) is also included, this 1487 also enables initial RAM disk (initrd) support and adds 1488 15 Kbytes (more on some other architectures) to the kernel size. 1489 1490 If unsure say Y. 1491 1492if BLK_DEV_INITRD 1493 1494source "usr/Kconfig" 1495 1496endif 1497 1498config BOOT_CONFIG 1499 bool "Boot config support" 1500 select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED 1501 help 1502 Extra boot config allows system admin to pass a config file as 1503 complemental extension of kernel cmdline when booting. 1504 The boot config file must be attached at the end of initramfs 1505 with checksum, size and magic word. 1506 See <file:Documentation/admin-guide/bootconfig.rst> for details. 1507 1508 If unsure, say Y. 1509 1510config BOOT_CONFIG_FORCE 1511 bool "Force unconditional bootconfig processing" 1512 depends on BOOT_CONFIG 1513 default y if BOOT_CONFIG_EMBED 1514 help 1515 With this Kconfig option set, BOOT_CONFIG processing is carried 1516 out even when the "bootconfig" kernel-boot parameter is omitted. 1517 In fact, with this Kconfig option set, there is no way to 1518 make the kernel ignore the BOOT_CONFIG-supplied kernel-boot 1519 parameters. 1520 1521 If unsure, say N. 1522 1523config BOOT_CONFIG_EMBED 1524 bool "Embed bootconfig file in the kernel" 1525 depends on BOOT_CONFIG 1526 help 1527 Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the 1528 kernel. Usually, the bootconfig file is loaded with the initrd 1529 image. But if the system doesn't support initrd, this option will 1530 help you by embedding a bootconfig file while building the kernel. 1531 1532 If unsure, say N. 1533 1534config BOOT_CONFIG_EMBED_FILE 1535 string "Embedded bootconfig file path" 1536 depends on BOOT_CONFIG_EMBED 1537 help 1538 Specify a bootconfig file which will be embedded to the kernel. 1539 This bootconfig will be used if there is no initrd or no other 1540 bootconfig in the initrd. 1541 1542config CMDLINE_LOG_WRAP_IDEAL_LEN 1543 int "Length to try to wrap the cmdline when logged at boot" 1544 default 1021 1545 range 0 1021 1546 help 1547 At boot time, the kernel command line is logged to the console. 1548 The log message will start with the prefix "Kernel command line: ". 1549 The log message will attempt to be wrapped (split into multiple log 1550 messages) at spaces based on CMDLINE_LOG_WRAP_IDEAL_LEN characters. 1551 If wrapping happens, each log message will start with the prefix and 1552 all but the last message will end with " \". Messages may exceed the 1553 ideal length if a place to wrap isn't found before the specified 1554 number of characters. 1555 1556 A value of 0 disables wrapping, though be warned that the maximum 1557 length of a log message (1021 characters) may cause the cmdline to 1558 be truncated. 1559 1560config INITRAMFS_PRESERVE_MTIME 1561 bool "Preserve cpio archive mtimes in initramfs" 1562 depends on BLK_DEV_INITRD 1563 default y 1564 help 1565 Each entry in an initramfs cpio archive carries an mtime value. When 1566 enabled, extracted cpio items take this mtime, with directory mtime 1567 setting deferred until after creation of any child entries. 1568 1569 If unsure, say Y. 1570 1571config INITRAMFS_TEST 1572 bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS 1573 depends on BLK_DEV_INITRD && KUNIT=y 1574 default KUNIT_ALL_TESTS 1575 help 1576 Build KUnit tests for initramfs. See Documentation/dev-tools/kunit 1577 1578choice 1579 prompt "Compiler optimization level" 1580 default CC_OPTIMIZE_FOR_PERFORMANCE 1581 1582config CC_OPTIMIZE_FOR_PERFORMANCE 1583 bool "Optimize for performance (-O2)" 1584 help 1585 This is the default optimization level for the kernel, building 1586 with the "-O2" compiler flag for best performance and most 1587 helpful compile-time warnings. 1588 1589config CC_OPTIMIZE_FOR_SIZE 1590 bool "Optimize for size (-Os)" 1591 help 1592 Choosing this option will pass "-Os" to your compiler resulting 1593 in a smaller kernel. 1594 1595endchoice 1596 1597config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1598 bool 1599 help 1600 This requires that the arch annotates or otherwise protects 1601 its external entry points from being discarded. Linker scripts 1602 must also merge .text.*, .data.*, and .bss.* correctly into 1603 output sections. Care must be taken not to pull in unrelated 1604 sections (e.g., '.text.init'). Typically '.' in section names 1605 is used to distinguish them from label names / C identifiers. 1606 1607config LD_DEAD_CODE_DATA_ELIMINATION 1608 bool "Dead code and data elimination (EXPERIMENTAL)" 1609 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1610 depends on EXPERT 1611 depends on $(cc-option,-ffunction-sections -fdata-sections) 1612 depends on $(ld-option,--gc-sections) 1613 help 1614 Enable this if you want to do dead code and data elimination with 1615 the linker by compiling with -ffunction-sections -fdata-sections, 1616 and linking with --gc-sections. 1617 1618 This can reduce on disk and in-memory size of the kernel 1619 code and static data, particularly for small configs and 1620 on small systems. This has the possibility of introducing 1621 silently broken kernel if the required annotations are not 1622 present. This option is not well tested yet, so use at your 1623 own risk. 1624 1625config LD_ORPHAN_WARN 1626 def_bool y 1627 depends on ARCH_WANT_LD_ORPHAN_WARN 1628 depends on $(ld-option,--orphan-handling=warn) 1629 depends on $(ld-option,--orphan-handling=error) 1630 1631config LD_ORPHAN_WARN_LEVEL 1632 string 1633 depends on LD_ORPHAN_WARN 1634 default "error" if WERROR 1635 default "warn" 1636 1637config SYSCTL 1638 bool 1639 1640config HAVE_UID16 1641 bool 1642 1643config SYSCTL_EXCEPTION_TRACE 1644 bool 1645 help 1646 Enable support for /proc/sys/debug/exception-trace. 1647 1648config SYSCTL_ARCH_UNALIGN_NO_WARN 1649 bool 1650 help 1651 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1652 Allows arch to define/use @no_unaligned_warning to possibly warn 1653 about unaligned access emulation going on under the hood. 1654 1655config SYSCTL_ARCH_UNALIGN_ALLOW 1656 bool 1657 help 1658 Enable support for /proc/sys/kernel/unaligned-trap 1659 Allows arches to define/use @unaligned_enabled to runtime toggle 1660 the unaligned access emulation. 1661 see arch/parisc/kernel/unaligned.c for reference 1662 1663config SYSFS_SYSCALL 1664 bool "Sysfs syscall support" 1665 default n 1666 help 1667 sys_sysfs is an obsolete system call no longer supported in libc. 1668 Note that disabling this option is more secure but might break 1669 compatibility with some systems. 1670 1671 If unsure say N here. 1672 1673config HAVE_PCSPKR_PLATFORM 1674 bool 1675 1676menuconfig EXPERT 1677 bool "Configure standard kernel features (expert users)" 1678 # Unhide debug options, to make the on-by-default options visible 1679 select DEBUG_KERNEL 1680 help 1681 This option allows certain base kernel options and settings 1682 to be disabled or tweaked. This is for specialized 1683 environments which can tolerate a "non-standard" kernel. 1684 Only use this if you really know what you are doing. 1685 1686config UID16 1687 bool "Enable 16-bit UID system calls" if EXPERT 1688 depends on HAVE_UID16 && MULTIUSER 1689 default y 1690 help 1691 This enables the legacy 16-bit UID syscall wrappers. 1692 1693config MULTIUSER 1694 bool "Multiple users, groups and capabilities support" if EXPERT 1695 default y 1696 help 1697 This option enables support for non-root users, groups and 1698 capabilities. 1699 1700 If you say N here, all processes will run with UID 0, GID 0, and all 1701 possible capabilities. Saying N here also compiles out support for 1702 system calls related to UIDs, GIDs, and capabilities, such as setuid, 1703 setgid, and capset. 1704 1705 If unsure, say Y here. 1706 1707config SGETMASK_SYSCALL 1708 bool "sgetmask/ssetmask syscalls support" if EXPERT 1709 default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH 1710 help 1711 sys_sgetmask and sys_ssetmask are obsolete system calls 1712 no longer supported in libc but still enabled by default in some 1713 architectures. 1714 1715 If unsure, leave the default option here. 1716 1717config FHANDLE 1718 bool "open by fhandle syscalls" if EXPERT 1719 select EXPORTFS 1720 default y 1721 help 1722 If you say Y here, a user level program will be able to map 1723 file names to handle and then later use the handle for 1724 different file system operations. This is useful in implementing 1725 userspace file servers, which now track files using handles instead 1726 of names. The handle would remain the same even if file names 1727 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 1728 syscalls. 1729 1730config POSIX_TIMERS 1731 bool "Posix Clocks & timers" if EXPERT 1732 default y 1733 help 1734 This includes native support for POSIX timers to the kernel. 1735 Some embedded systems have no use for them and therefore they 1736 can be configured out to reduce the size of the kernel image. 1737 1738 When this option is disabled, the following syscalls won't be 1739 available: timer_create, timer_gettime: timer_getoverrun, 1740 timer_settime, timer_delete, clock_adjtime, getitimer, 1741 setitimer, alarm. Furthermore, the clock_settime, clock_gettime, 1742 clock_getres and clock_nanosleep syscalls will be limited to 1743 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. 1744 1745 If unsure say y. 1746 1747config PRINTK 1748 default y 1749 bool "Enable support for printk" if EXPERT 1750 select IRQ_WORK 1751 help 1752 This option enables normal printk support. Removing it 1753 eliminates most of the message strings from the kernel image 1754 and makes the kernel more or less silent. As this makes it 1755 very difficult to diagnose system problems, saying N here is 1756 strongly discouraged. 1757 1758config PRINTK_RINGBUFFER_KUNIT_TEST 1759 tristate "KUnit Test for the printk ringbuffer" if !KUNIT_ALL_TESTS 1760 depends on PRINTK && KUNIT 1761 default KUNIT_ALL_TESTS 1762 help 1763 This builds the printk ringbuffer KUnit test suite. 1764 1765 For more information on KUnit and unit tests in general, please refer 1766 to the KUnit documentation. 1767 1768 If unsure, say N. 1769 1770config BUG 1771 bool "BUG() support" if EXPERT 1772 default y 1773 help 1774 Disabling this option eliminates support for BUG and WARN, reducing 1775 the size of your kernel image and potentially quietly ignoring 1776 numerous fatal conditions. You should only consider disabling this 1777 option for embedded systems with no facilities for reporting errors. 1778 Just say Y. 1779 1780config ELF_CORE 1781 depends on COREDUMP 1782 default y 1783 bool "Enable ELF core dumps" if EXPERT 1784 help 1785 Enable support for generating core dumps. Disabling saves about 4k. 1786 1787 1788config PCSPKR_PLATFORM 1789 bool "Enable PC-Speaker support" if EXPERT 1790 depends on HAVE_PCSPKR_PLATFORM 1791 select I8253_LOCK 1792 default y 1793 help 1794 This option allows to disable the internal PC-Speaker 1795 support, saving some memory. 1796 1797config BASE_SMALL 1798 bool "Enable smaller-sized data structures for core" if EXPERT 1799 help 1800 Enabling this option reduces the size of miscellaneous core 1801 kernel data structures. This saves memory on small machines, 1802 but may reduce performance. 1803 1804config FUTEX 1805 bool "Enable futex support" if EXPERT 1806 depends on !(SPARC32 && SMP) 1807 default y 1808 imply RT_MUTEXES 1809 help 1810 Disabling this option will cause the kernel to be built without 1811 support for "fast userspace mutexes". The resulting kernel may not 1812 run glibc-based applications correctly. 1813 1814config FUTEX_PI 1815 bool 1816 depends on FUTEX && RT_MUTEXES 1817 default y 1818 1819config FUTEX_PRIVATE_HASH 1820 bool 1821 depends on FUTEX && !BASE_SMALL && MMU 1822 default y 1823 1824config FUTEX_MPOL 1825 bool 1826 depends on FUTEX && NUMA 1827 default y 1828 1829config EPOLL 1830 bool "Enable eventpoll support" if EXPERT 1831 default y 1832 help 1833 Disabling this option will cause the kernel to be built without 1834 support for epoll family of system calls. 1835 1836config SIGNALFD 1837 bool "Enable signalfd() system call" if EXPERT 1838 default y 1839 help 1840 Enable the signalfd() system call that allows to receive signals 1841 on a file descriptor. 1842 1843 If unsure, say Y. 1844 1845config TIMERFD 1846 bool "Enable timerfd() system call" if EXPERT 1847 default y 1848 help 1849 Enable the timerfd() system call that allows to receive timer 1850 events on a file descriptor. 1851 1852 If unsure, say Y. 1853 1854config EVENTFD 1855 bool "Enable eventfd() system call" if EXPERT 1856 default y 1857 help 1858 Enable the eventfd() system call that allows to receive both 1859 kernel notification (ie. KAIO) or userspace notifications. 1860 1861 If unsure, say Y. 1862 1863config SHMEM 1864 bool "Use full shmem filesystem" if EXPERT 1865 default y 1866 depends on MMU 1867 help 1868 The shmem is an internal filesystem used to manage shared memory. 1869 It is backed by swap and manages resource limits. It is also exported 1870 to userspace as tmpfs if TMPFS is enabled. Disabling this 1871 option replaces shmem and tmpfs with the much simpler ramfs code, 1872 which may be appropriate on small systems without swap. 1873 1874config AIO 1875 bool "Enable AIO support" if EXPERT 1876 default y 1877 help 1878 This option enables POSIX asynchronous I/O which may by used 1879 by some high performance threaded applications. Disabling 1880 this option saves about 7k. 1881 1882config IO_URING 1883 bool "Enable IO uring support" if EXPERT 1884 select IO_WQ 1885 default y 1886 help 1887 This option enables support for the io_uring interface, enabling 1888 applications to submit and complete IO through submission and 1889 completion rings that are shared between the kernel and application. 1890 1891config GCOV_PROFILE_URING 1892 bool "Enable GCOV profiling on the io_uring subsystem" 1893 depends on IO_URING && GCOV_KERNEL 1894 help 1895 Enable GCOV profiling on the io_uring subsystem, to facilitate 1896 code coverage testing. 1897 1898 If unsure, say N. 1899 1900 Note that this will have a negative impact on the performance of 1901 the io_uring subsystem, hence this should only be enabled for 1902 specific test purposes. 1903 1904config IO_URING_MOCK_FILE 1905 tristate "Enable io_uring mock files (Experimental)" if EXPERT 1906 default n 1907 depends on IO_URING 1908 help 1909 Enable mock files for io_uring subststem testing. The ABI might 1910 still change, so it's still experimental and should only be enabled 1911 for specific test purposes. 1912 1913 If unsure, say N. 1914 1915config ADVISE_SYSCALLS 1916 bool "Enable madvise/fadvise syscalls" if EXPERT 1917 default y 1918 help 1919 This option enables the madvise and fadvise syscalls, used by 1920 applications to advise the kernel about their future memory or file 1921 usage, improving performance. If building an embedded system where no 1922 applications use these syscalls, you can disable this option to save 1923 space. 1924 1925config MEMBARRIER 1926 bool "Enable membarrier() system call" if EXPERT 1927 default y 1928 help 1929 Enable the membarrier() system call that allows issuing memory 1930 barriers across all running threads, which can be used to distribute 1931 the cost of user-space memory barriers asymmetrically by transforming 1932 pairs of memory barriers into pairs consisting of membarrier() and a 1933 compiler barrier. 1934 1935 If unsure, say Y. 1936 1937config KCMP 1938 bool "Enable kcmp() system call" if EXPERT 1939 help 1940 Enable the kernel resource comparison system call. It provides 1941 user-space with the ability to compare two processes to see if they 1942 share a common resource, such as a file descriptor or even virtual 1943 memory space. 1944 1945 If unsure, say N. 1946 1947config RSEQ 1948 bool "Enable rseq() system call" if EXPERT 1949 default y 1950 depends on HAVE_RSEQ 1951 select MEMBARRIER 1952 help 1953 Enable the restartable sequences system call. It provides a 1954 user-space cache for the current CPU number value, which 1955 speeds up getting the current CPU number from user-space, 1956 as well as an ABI to speed up user-space operations on 1957 per-CPU data. 1958 1959 If unsure, say Y. 1960 1961config RSEQ_SLICE_EXTENSION 1962 bool "Enable rseq-based time slice extension mechanism" 1963 depends on RSEQ && HIGH_RES_TIMERS && GENERIC_ENTRY && HAVE_GENERIC_TIF_BITS 1964 help 1965 Allows userspace to request a limited time slice extension when 1966 returning from an interrupt to user space via the RSEQ shared 1967 data ABI. If granted, that allows to complete a critical section, 1968 so that other threads are not stuck on a conflicted resource, 1969 while the task is scheduled out. 1970 1971 If unsure, say N. 1972 1973config RSEQ_STATS 1974 default n 1975 bool "Enable lightweight statistics of restartable sequences" if EXPERT 1976 depends on RSEQ && DEBUG_FS 1977 help 1978 Enable lightweight counters which expose information about the 1979 frequency of RSEQ operations via debugfs. Mostly interesting for 1980 kernel debugging or performance analysis. While lightweight it's 1981 still adding code into the user/kernel mode transitions. 1982 1983 If unsure, say N. 1984 1985config RSEQ_DEBUG_DEFAULT_ENABLE 1986 default n 1987 bool "Enable restartable sequences debug mode by default" if EXPERT 1988 depends on RSEQ 1989 help 1990 This enables the static branch for debug mode of restartable 1991 sequences. 1992 1993 This also can be controlled on the kernel command line via the 1994 command line parameter "rseq_debug=0/1" and through debugfs. 1995 1996 If unsure, say N. 1997 1998config DEBUG_RSEQ 1999 default n 2000 bool "Enable debugging of rseq() system call" if EXPERT 2001 depends on RSEQ && DEBUG_KERNEL && !GENERIC_ENTRY 2002 select RSEQ_DEBUG_DEFAULT_ENABLE 2003 help 2004 Enable extra debugging checks for the rseq system call. 2005 2006 If unsure, say N. 2007 2008config CACHESTAT_SYSCALL 2009 bool "Enable cachestat() system call" if EXPERT 2010 default y 2011 help 2012 Enable the cachestat system call, which queries the page cache 2013 statistics of a file (number of cached pages, dirty pages, 2014 pages marked for writeback, (recently) evicted pages). 2015 2016 If unsure say Y here. 2017 2018config KALLSYMS 2019 bool "Load all symbols for debugging/ksymoops" if EXPERT 2020 default y 2021 help 2022 Say Y here to let the kernel print out symbolic crash information and 2023 symbolic stack backtraces. This increases the size of the kernel 2024 somewhat, as all symbols have to be loaded into the kernel image. 2025 2026config KALLSYMS_SELFTEST 2027 bool "Test the basic functions and performance of kallsyms" 2028 depends on KALLSYMS 2029 default n 2030 help 2031 Test the basic functions and performance of some interfaces, such as 2032 kallsyms_lookup_name. It also calculates the compression rate of the 2033 kallsyms compression algorithm for the current symbol set. 2034 2035 Start self-test automatically after system startup. Suggest executing 2036 "dmesg | grep kallsyms_selftest" to collect test results. "finish" is 2037 displayed in the last line, indicating that the test is complete. 2038 2039config KALLSYMS_ALL 2040 bool "Include all symbols in kallsyms" 2041 depends on DEBUG_KERNEL && KALLSYMS 2042 help 2043 Normally kallsyms only contains the symbols of functions for nicer 2044 OOPS messages and backtraces (i.e., symbols from the text and inittext 2045 sections). This is sufficient for most cases. And only if you want to 2046 enable kernel live patching, or other less common use cases (e.g., 2047 when a debugger is used) all symbols are required (i.e., names of 2048 variables from the data sections, etc). 2049 2050 This option makes sure that all symbols are loaded into the kernel 2051 image (i.e., symbols from all sections) in cost of increased kernel 2052 size (depending on the kernel configuration, it may be 300KiB or 2053 something like this). 2054 2055 Say N unless you really need all symbols, or kernel live patching. 2056 2057# end of the "standard kernel features (expert users)" menu 2058 2059config ARCH_HAS_MEMBARRIER_CALLBACKS 2060 bool 2061 2062config ARCH_HAS_MEMBARRIER_SYNC_CORE 2063 bool 2064 2065config ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 2066 bool 2067 help 2068 Control MSEAL_SYSTEM_MAPPINGS access based on architecture. 2069 2070 A 64-bit kernel is required for the memory sealing feature. 2071 No specific hardware features from the CPU are needed. 2072 2073 To enable this feature, the architecture needs to update their 2074 special mappings calls to include the sealing flag and confirm 2075 that it doesn't unmap/remap system mappings during the life 2076 time of the process. The existence of this flag for an architecture 2077 implies that it does not require the remapping of the system 2078 mappings during process lifetime, so sealing these mappings is safe 2079 from a kernel perspective. 2080 2081 After the architecture enables this, a distribution can set 2082 CONFIG_MSEAL_SYSTEM_MAPPING to manage access to the feature. 2083 2084 For complete descriptions of memory sealing, please see 2085 Documentation/userspace-api/mseal.rst 2086 2087config HAVE_PERF_EVENTS 2088 bool 2089 help 2090 See tools/perf/design.txt for details. 2091 2092config GUEST_PERF_EVENTS 2093 bool 2094 depends on HAVE_PERF_EVENTS 2095 2096config PERF_GUEST_MEDIATED_PMU 2097 bool 2098 depends on GUEST_PERF_EVENTS 2099 2100config PERF_USE_VMALLOC 2101 bool 2102 help 2103 See tools/perf/design.txt for details 2104 2105menu "Kernel Performance Events And Counters" 2106 2107config PERF_EVENTS 2108 bool "Kernel performance events and counters" 2109 default y if PROFILING 2110 depends on HAVE_PERF_EVENTS 2111 select IRQ_WORK 2112 help 2113 Enable kernel support for various performance events provided 2114 by software and hardware. 2115 2116 Software events are supported either built-in or via the 2117 use of generic tracepoints. 2118 2119 Most modern CPUs support performance events via performance 2120 counter registers. These registers count the number of certain 2121 types of hw events: such as instructions executed, cachemisses 2122 suffered, or branches mis-predicted - without slowing down the 2123 kernel or applications. These registers can also trigger interrupts 2124 when a threshold number of events have passed - and can thus be 2125 used to profile the code that runs on that CPU. 2126 2127 The Linux Performance Event subsystem provides an abstraction of 2128 these software and hardware event capabilities, available via a 2129 system call and used by the "perf" utility in tools/perf/. It 2130 provides per task and per CPU counters, and it provides event 2131 capabilities on top of those. 2132 2133 Say Y if unsure. 2134 2135config DEBUG_PERF_USE_VMALLOC 2136 default n 2137 bool "Debug: use vmalloc to back perf mmap() buffers" 2138 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC 2139 select PERF_USE_VMALLOC 2140 help 2141 Use vmalloc memory to back perf mmap() buffers. 2142 2143 Mostly useful for debugging the vmalloc code on platforms 2144 that don't require it. 2145 2146 Say N if unsure. 2147 2148endmenu 2149 2150config SYSTEM_DATA_VERIFICATION 2151 def_bool n 2152 select SYSTEM_TRUSTED_KEYRING 2153 select KEYS 2154 select CRYPTO 2155 select CRYPTO_RSA 2156 select ASYMMETRIC_KEY_TYPE 2157 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 2158 select ASN1 2159 select OID_REGISTRY 2160 select X509_CERTIFICATE_PARSER 2161 select PKCS7_MESSAGE_PARSER 2162 help 2163 Provide PKCS#7 message verification using the contents of the system 2164 trusted keyring to provide public keys. This then can be used for 2165 module verification, kexec image verification and firmware blob 2166 verification. 2167 2168config PROFILING 2169 bool "Profiling support" 2170 help 2171 Say Y here to enable the extended profiling support mechanisms used 2172 by profilers. 2173 2174config RUST 2175 bool "Rust support" 2176 depends on HAVE_RUST 2177 depends on RUST_IS_AVAILABLE 2178 select EXTENDED_MODVERSIONS if MODVERSIONS 2179 depends on !MODVERSIONS || GENDWARFKSYMS 2180 depends on !GCC_PLUGIN_RANDSTRUCT 2181 depends on !RANDSTRUCT 2182 depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO) 2183 depends on !CFI || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC 2184 select CFI_ICALL_NORMALIZE_INTEGERS if CFI 2185 depends on !CALL_PADDING || RUSTC_VERSION >= 108100 2186 depends on !KASAN_SW_TAGS 2187 depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300 2188 help 2189 Enables Rust support in the kernel. 2190 2191 This allows other Rust-related options, like drivers written in Rust, 2192 to be selected. 2193 2194 It is also required to be able to load external kernel modules 2195 written in Rust. 2196 2197 See Documentation/rust/ for more information. 2198 2199 If unsure, say N. 2200 2201config RUSTC_VERSION_TEXT 2202 string 2203 depends on RUST 2204 default "$(RUSTC_VERSION_TEXT)" 2205 help 2206 See `CC_VERSION_TEXT`. 2207 2208config BINDGEN_VERSION_TEXT 2209 string 2210 depends on RUST 2211 # The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0 2212 # (https://github.com/rust-lang/rust-bindgen/pull/2678) and 0.71.0 2213 # (https://github.com/rust-lang/rust-bindgen/pull/3040). It can be removed 2214 # when the minimum version is upgraded past the latter (0.69.1 and 0.71.1 2215 # both fixed the issue). 2216 default "$(shell,$(BINDGEN) --version workaround-for-0.69.0 2>/dev/null)" 2217 2218# 2219# Place an empty function call at each tracepoint site. Can be 2220# dynamically changed for a probe function. 2221# 2222config TRACEPOINTS 2223 bool 2224 select TASKS_TRACE_RCU 2225 2226source "kernel/Kconfig.kexec" 2227 2228source "kernel/liveupdate/Kconfig" 2229 2230endmenu # General setup 2231 2232source "arch/Kconfig" 2233 2234config RT_MUTEXES 2235 bool 2236 default y if PREEMPT_RT 2237 2238config MODULE_SIG_FORMAT 2239 def_bool n 2240 select SYSTEM_DATA_VERIFICATION 2241 2242source "kernel/module/Kconfig" 2243 2244config INIT_ALL_POSSIBLE 2245 bool 2246 help 2247 Back when each arch used to define their own cpu_online_mask and 2248 cpu_possible_mask, some of them chose to initialize cpu_possible_mask 2249 with all 1s, and others with all 0s. When they were centralised, 2250 it was better to provide this option than to break all the archs 2251 and have several arch maintainers pursuing me down dark alleys. 2252 2253source "block/Kconfig" 2254 2255config PREEMPT_NOTIFIERS 2256 bool 2257 2258config PADATA 2259 depends on SMP 2260 bool 2261 2262config ASN1 2263 tristate 2264 help 2265 Build a simple ASN.1 grammar compiler that produces a bytecode output 2266 that can be interpreted by the ASN.1 stream decoder and used to 2267 inform it as to what tags are to be expected in a stream and what 2268 functions to call on what tags. 2269 2270source "kernel/Kconfig.locks" 2271 2272config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 2273 bool 2274 2275config ARCH_HAS_PREPARE_SYNC_CORE_CMD 2276 bool 2277 2278config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2279 bool 2280 2281# It may be useful for an architecture to override the definitions of the 2282# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> 2283# and the COMPAT_ variants in <linux/compat.h>, in particular to use a 2284# different calling convention for syscalls. They can also override the 2285# macros for not-implemented syscalls in kernel/sys_ni.c and 2286# kernel/time/posix-stubs.c. All these overrides need to be available in 2287# <asm/syscall_wrapper.h>. 2288config ARCH_HAS_SYSCALL_WRAPPER 2289 def_bool n 2290