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 < 220000 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 SCHED_MM_CID 1180 def_bool y 1181 depends on SMP && RSEQ 1182 1183config UCLAMP_TASK_GROUP 1184 bool "Utilization clamping per group of tasks" 1185 depends on CGROUP_SCHED 1186 depends on UCLAMP_TASK 1187 default n 1188 help 1189 This feature enables the scheduler to track the clamped utilization 1190 of each CPU based on RUNNABLE tasks currently scheduled on that CPU. 1191 1192 When this option is enabled, the user can specify a min and max 1193 CPU bandwidth which is allowed for each single task in a group. 1194 The max bandwidth allows to clamp the maximum frequency a task 1195 can use, while the min bandwidth allows to define a minimum 1196 frequency a task will always use. 1197 1198 When task group based utilization clamping is enabled, an eventually 1199 specified task-specific clamp value is constrained by the cgroup 1200 specified clamp value. Both minimum and maximum task clamping cannot 1201 be bigger than the corresponding clamping defined at task group level. 1202 1203 If in doubt, say N. 1204 1205config CGROUP_PIDS 1206 bool "PIDs controller" 1207 help 1208 Provides enforcement of process number limits in the scope of a 1209 cgroup. Any attempt to fork more processes than is allowed in the 1210 cgroup will fail. PIDs are fundamentally a global resource because it 1211 is fairly trivial to reach PID exhaustion before you reach even a 1212 conservative kmemcg limit. As a result, it is possible to grind a 1213 system to halt without being limited by other cgroup policies. The 1214 PIDs controller is designed to stop this from happening. 1215 1216 It should be noted that organisational operations (such as attaching 1217 to a cgroup hierarchy) will *not* be blocked by the PIDs controller, 1218 since the PIDs limit only affects a process's ability to fork, not to 1219 attach to a cgroup. 1220 1221config CGROUP_RDMA 1222 bool "RDMA controller" 1223 help 1224 Provides enforcement of RDMA resources defined by IB stack. 1225 It is fairly easy for consumers to exhaust RDMA resources, which 1226 can result into resource unavailability to other consumers. 1227 RDMA controller is designed to stop this from happening. 1228 Attaching processes with active RDMA resources to the cgroup 1229 hierarchy is allowed even if can cross the hierarchy's limit. 1230 1231config CGROUP_DMEM 1232 bool "Device memory controller (DMEM)" 1233 select PAGE_COUNTER 1234 help 1235 The DMEM controller allows compatible devices to restrict device 1236 memory usage based on the cgroup hierarchy. 1237 1238 As an example, it allows you to restrict VRAM usage for applications 1239 in the DRM subsystem. 1240 1241config CGROUP_FREEZER 1242 bool "Freezer controller" 1243 help 1244 Provides a way to freeze and unfreeze all tasks in a 1245 cgroup. 1246 1247 This option affects the ORIGINAL cgroup interface. The cgroup2 memory 1248 controller includes important in-kernel memory consumers per default. 1249 1250 If you're using cgroup2, say N. 1251 1252config CGROUP_HUGETLB 1253 bool "HugeTLB controller" 1254 depends on HUGETLB_PAGE 1255 select PAGE_COUNTER 1256 default n 1257 help 1258 Provides a cgroup controller for HugeTLB pages. 1259 When you enable this, you can put a per cgroup limit on HugeTLB usage. 1260 The limit is enforced during page fault. Since HugeTLB doesn't 1261 support page reclaim, enforcing the limit at page fault time implies 1262 that, the application will get SIGBUS signal if it tries to access 1263 HugeTLB pages beyond its limit. This requires the application to know 1264 beforehand how much HugeTLB pages it would require for its use. The 1265 control group is tracked in the third page lru pointer. This means 1266 that we cannot use the controller with huge page less than 3 pages. 1267 1268config CPUSETS 1269 bool "Cpuset controller" 1270 depends on SMP 1271 select UNION_FIND 1272 select CPU_ISOLATION 1273 help 1274 This option will let you create and manage CPUSETs which 1275 allow dynamically partitioning a system into sets of CPUs and 1276 Memory Nodes and assigning tasks to run only within those sets. 1277 This is primarily useful on large SMP or NUMA systems. 1278 1279 Say N if unsure. 1280 1281config CPUSETS_V1 1282 bool "Legacy cgroup v1 cpusets controller" 1283 depends on CPUSETS 1284 default n 1285 help 1286 Legacy cgroup v1 cpusets controller which has been deprecated by 1287 cgroup v2 implementation. The v1 is there for legacy applications 1288 which haven't migrated to the new cgroup v2 interface yet. Legacy 1289 interface includes cpuset filesystem and /proc/<pid>/cpuset. If you 1290 do not have any such application then you are completely fine leaving 1291 this option disabled. 1292 1293 Say N if unsure. 1294 1295config PROC_PID_CPUSET 1296 bool "Include legacy /proc/<pid>/cpuset file" 1297 depends on CPUSETS_V1 1298 default y 1299 1300config CGROUP_DEVICE 1301 bool "Device controller" 1302 help 1303 Provides a cgroup controller implementing whitelists for 1304 devices which a process in the cgroup can mknod or open. 1305 1306config CGROUP_CPUACCT 1307 bool "Simple CPU accounting controller" 1308 help 1309 Provides a simple controller for monitoring the 1310 total CPU consumed by the tasks in a cgroup. 1311 1312config CGROUP_PERF 1313 bool "Perf controller" 1314 depends on PERF_EVENTS 1315 help 1316 This option extends the perf per-cpu mode to restrict monitoring 1317 to threads which belong to the cgroup specified and run on the 1318 designated cpu. Or this can be used to have cgroup ID in samples 1319 so that it can monitor performance events among cgroups. 1320 1321 Say N if unsure. 1322 1323config CGROUP_BPF 1324 bool "Support for eBPF programs attached to cgroups" 1325 depends on BPF_SYSCALL 1326 select SOCK_CGROUP_DATA 1327 help 1328 Allow attaching eBPF programs to a cgroup using the bpf(2) 1329 syscall command BPF_PROG_ATTACH. 1330 1331 In which context these programs are accessed depends on the type 1332 of attachment. For instance, programs that are attached using 1333 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of 1334 inet sockets. 1335 1336config CGROUP_MISC 1337 bool "Misc resource controller" 1338 default n 1339 help 1340 Provides a controller for miscellaneous resources on a host. 1341 1342 Miscellaneous scalar resources are the resources on the host system 1343 which cannot be abstracted like the other cgroups. This controller 1344 tracks and limits the miscellaneous resources used by a process 1345 attached to a cgroup hierarchy. 1346 1347 For more information, please check misc cgroup section in 1348 /Documentation/admin-guide/cgroup-v2.rst. 1349 1350config CGROUP_DEBUG 1351 bool "Debug controller" 1352 default n 1353 depends on DEBUG_KERNEL 1354 help 1355 This option enables a simple controller that exports 1356 debugging information about the cgroups framework. This 1357 controller is for control cgroup debugging only. Its 1358 interfaces are not stable. 1359 1360 Say N. 1361 1362config SOCK_CGROUP_DATA 1363 bool 1364 default n 1365 1366endif # CGROUPS 1367 1368menuconfig NAMESPACES 1369 bool "Namespaces support" if EXPERT 1370 depends on MULTIUSER 1371 default !EXPERT 1372 help 1373 Provides the way to make tasks work with different objects using 1374 the same id. For example same IPC id may refer to different objects 1375 or same user id or pid may refer to different tasks when used in 1376 different namespaces. 1377 1378if NAMESPACES 1379 1380config UTS_NS 1381 bool "UTS namespace" 1382 default y 1383 help 1384 In this namespace tasks see different info provided with the 1385 uname() system call 1386 1387config TIME_NS 1388 bool "TIME namespace" 1389 depends on GENERIC_GETTIMEOFDAY 1390 default y 1391 help 1392 In this namespace boottime and monotonic clocks can be set. 1393 The time will keep going with the same pace. 1394 1395config IPC_NS 1396 bool "IPC namespace" 1397 depends on (SYSVIPC || POSIX_MQUEUE) 1398 default y 1399 help 1400 In this namespace tasks work with IPC ids which correspond to 1401 different IPC objects in different namespaces. 1402 1403config USER_NS 1404 bool "User namespace" 1405 default n 1406 help 1407 This allows containers, i.e. vservers, to use user namespaces 1408 to provide different user info for different servers. 1409 1410 When user namespaces are enabled in the kernel it is 1411 recommended that the MEMCG option also be enabled and that 1412 user-space use the memory control groups to limit the amount 1413 of memory a memory unprivileged users can use. 1414 1415 If unsure, say N. 1416 1417config PID_NS 1418 bool "PID Namespaces" 1419 default y 1420 help 1421 Support process id namespaces. This allows having multiple 1422 processes with the same pid as long as they are in different 1423 pid namespaces. This is a building block of containers. 1424 1425config NET_NS 1426 bool "Network namespace" 1427 depends on NET 1428 default y 1429 help 1430 Allow user space to create what appear to be multiple instances 1431 of the network stack. 1432 1433endif # NAMESPACES 1434 1435config CHECKPOINT_RESTORE 1436 bool "Checkpoint/restore support" 1437 depends on PROC_FS 1438 select PROC_CHILDREN 1439 select KCMP 1440 default n 1441 help 1442 Enables additional kernel features in a sake of checkpoint/restore. 1443 In particular it adds auxiliary prctl codes to setup process text, 1444 data and heap segment sizes, and a few additional /proc filesystem 1445 entries. 1446 1447 If unsure, say N here. 1448 1449config SCHED_AUTOGROUP 1450 bool "Automatic process group scheduling" 1451 select CGROUPS 1452 select CGROUP_SCHED 1453 select FAIR_GROUP_SCHED 1454 help 1455 This option optimizes the scheduler for common desktop workloads by 1456 automatically creating and populating task groups. This separation 1457 of workloads isolates aggressive CPU burners (like build jobs) from 1458 desktop applications. Task group autogeneration is currently based 1459 upon task session. 1460 1461config RELAY 1462 bool "Kernel->user space relay support (formerly relayfs)" 1463 select IRQ_WORK 1464 help 1465 This option enables support for relay interface support in 1466 certain file systems (such as debugfs). 1467 It is designed to provide an efficient mechanism for tools and 1468 facilities to relay large amounts of data from kernel space to 1469 user space. 1470 1471 If unsure, say N. 1472 1473config BLK_DEV_INITRD 1474 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1475 help 1476 The initial RAM filesystem is a ramfs which is loaded by the 1477 boot loader (loadlin or lilo) and that is mounted as root 1478 before the normal boot procedure. It is typically used to 1479 load modules needed to mount the "real" root file system, 1480 etc. See <file:Documentation/admin-guide/initrd.rst> for details. 1481 1482 If RAM disk support (BLK_DEV_RAM) is also included, this 1483 also enables initial RAM disk (initrd) support and adds 1484 15 Kbytes (more on some other architectures) to the kernel size. 1485 1486 If unsure say Y. 1487 1488if BLK_DEV_INITRD 1489 1490source "usr/Kconfig" 1491 1492endif 1493 1494config BOOT_CONFIG 1495 bool "Boot config support" 1496 select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED 1497 help 1498 Extra boot config allows system admin to pass a config file as 1499 complemental extension of kernel cmdline when booting. 1500 The boot config file must be attached at the end of initramfs 1501 with checksum, size and magic word. 1502 See <file:Documentation/admin-guide/bootconfig.rst> for details. 1503 1504 If unsure, say Y. 1505 1506config BOOT_CONFIG_FORCE 1507 bool "Force unconditional bootconfig processing" 1508 depends on BOOT_CONFIG 1509 default y if BOOT_CONFIG_EMBED 1510 help 1511 With this Kconfig option set, BOOT_CONFIG processing is carried 1512 out even when the "bootconfig" kernel-boot parameter is omitted. 1513 In fact, with this Kconfig option set, there is no way to 1514 make the kernel ignore the BOOT_CONFIG-supplied kernel-boot 1515 parameters. 1516 1517 If unsure, say N. 1518 1519config BOOT_CONFIG_EMBED 1520 bool "Embed bootconfig file in the kernel" 1521 depends on BOOT_CONFIG 1522 help 1523 Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the 1524 kernel. Usually, the bootconfig file is loaded with the initrd 1525 image. But if the system doesn't support initrd, this option will 1526 help you by embedding a bootconfig file while building the kernel. 1527 1528 If unsure, say N. 1529 1530config BOOT_CONFIG_EMBED_FILE 1531 string "Embedded bootconfig file path" 1532 depends on BOOT_CONFIG_EMBED 1533 help 1534 Specify a bootconfig file which will be embedded to the kernel. 1535 This bootconfig will be used if there is no initrd or no other 1536 bootconfig in the initrd. 1537 1538config CMDLINE_LOG_WRAP_IDEAL_LEN 1539 int "Length to try to wrap the cmdline when logged at boot" 1540 default 1021 1541 range 0 1021 1542 help 1543 At boot time, the kernel command line is logged to the console. 1544 The log message will start with the prefix "Kernel command line: ". 1545 The log message will attempt to be wrapped (split into multiple log 1546 messages) at spaces based on CMDLINE_LOG_WRAP_IDEAL_LEN characters. 1547 If wrapping happens, each log message will start with the prefix and 1548 all but the last message will end with " \". Messages may exceed the 1549 ideal length if a place to wrap isn't found before the specified 1550 number of characters. 1551 1552 A value of 0 disables wrapping, though be warned that the maximum 1553 length of a log message (1021 characters) may cause the cmdline to 1554 be truncated. 1555 1556config INITRAMFS_PRESERVE_MTIME 1557 bool "Preserve cpio archive mtimes in initramfs" 1558 depends on BLK_DEV_INITRD 1559 default y 1560 help 1561 Each entry in an initramfs cpio archive carries an mtime value. When 1562 enabled, extracted cpio items take this mtime, with directory mtime 1563 setting deferred until after creation of any child entries. 1564 1565 If unsure, say Y. 1566 1567config INITRAMFS_TEST 1568 bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS 1569 depends on BLK_DEV_INITRD && KUNIT=y 1570 default KUNIT_ALL_TESTS 1571 help 1572 Build KUnit tests for initramfs. See Documentation/dev-tools/kunit 1573 1574choice 1575 prompt "Compiler optimization level" 1576 default CC_OPTIMIZE_FOR_PERFORMANCE 1577 1578config CC_OPTIMIZE_FOR_PERFORMANCE 1579 bool "Optimize for performance (-O2)" 1580 help 1581 This is the default optimization level for the kernel, building 1582 with the "-O2" compiler flag for best performance and most 1583 helpful compile-time warnings. 1584 1585config CC_OPTIMIZE_FOR_SIZE 1586 bool "Optimize for size (-Os)" 1587 help 1588 Choosing this option will pass "-Os" to your compiler resulting 1589 in a smaller kernel. 1590 1591endchoice 1592 1593config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1594 bool 1595 help 1596 This requires that the arch annotates or otherwise protects 1597 its external entry points from being discarded. Linker scripts 1598 must also merge .text.*, .data.*, and .bss.* correctly into 1599 output sections. Care must be taken not to pull in unrelated 1600 sections (e.g., '.text.init'). Typically '.' in section names 1601 is used to distinguish them from label names / C identifiers. 1602 1603config LD_DEAD_CODE_DATA_ELIMINATION 1604 bool "Dead code and data elimination (EXPERIMENTAL)" 1605 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1606 depends on EXPERT 1607 depends on $(cc-option,-ffunction-sections -fdata-sections) 1608 depends on $(ld-option,--gc-sections) 1609 help 1610 Enable this if you want to do dead code and data elimination with 1611 the linker by compiling with -ffunction-sections -fdata-sections, 1612 and linking with --gc-sections. 1613 1614 This can reduce on disk and in-memory size of the kernel 1615 code and static data, particularly for small configs and 1616 on small systems. This has the possibility of introducing 1617 silently broken kernel if the required annotations are not 1618 present. This option is not well tested yet, so use at your 1619 own risk. 1620 1621config LD_ORPHAN_WARN 1622 def_bool y 1623 depends on ARCH_WANT_LD_ORPHAN_WARN 1624 depends on $(ld-option,--orphan-handling=warn) 1625 depends on $(ld-option,--orphan-handling=error) 1626 1627config LD_ORPHAN_WARN_LEVEL 1628 string 1629 depends on LD_ORPHAN_WARN 1630 default "error" if WERROR 1631 default "warn" 1632 1633config SYSCTL 1634 bool 1635 1636config HAVE_UID16 1637 bool 1638 1639config SYSCTL_EXCEPTION_TRACE 1640 bool 1641 help 1642 Enable support for /proc/sys/debug/exception-trace. 1643 1644config SYSCTL_ARCH_UNALIGN_NO_WARN 1645 bool 1646 help 1647 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1648 Allows arch to define/use @no_unaligned_warning to possibly warn 1649 about unaligned access emulation going on under the hood. 1650 1651config SYSCTL_ARCH_UNALIGN_ALLOW 1652 bool 1653 help 1654 Enable support for /proc/sys/kernel/unaligned-trap 1655 Allows arches to define/use @unaligned_enabled to runtime toggle 1656 the unaligned access emulation. 1657 see arch/parisc/kernel/unaligned.c for reference 1658 1659config SYSFS_SYSCALL 1660 bool "Sysfs syscall support" 1661 default n 1662 help 1663 sys_sysfs is an obsolete system call no longer supported in libc. 1664 Note that disabling this option is more secure but might break 1665 compatibility with some systems. 1666 1667 If unsure say N here. 1668 1669config HAVE_PCSPKR_PLATFORM 1670 bool 1671 1672menuconfig EXPERT 1673 bool "Configure standard kernel features (expert users)" 1674 # Unhide debug options, to make the on-by-default options visible 1675 select DEBUG_KERNEL 1676 help 1677 This option allows certain base kernel options and settings 1678 to be disabled or tweaked. This is for specialized 1679 environments which can tolerate a "non-standard" kernel. 1680 Only use this if you really know what you are doing. 1681 1682config UID16 1683 bool "Enable 16-bit UID system calls" if EXPERT 1684 depends on HAVE_UID16 && MULTIUSER 1685 default y 1686 help 1687 This enables the legacy 16-bit UID syscall wrappers. 1688 1689config MULTIUSER 1690 bool "Multiple users, groups and capabilities support" if EXPERT 1691 default y 1692 help 1693 This option enables support for non-root users, groups and 1694 capabilities. 1695 1696 If you say N here, all processes will run with UID 0, GID 0, and all 1697 possible capabilities. Saying N here also compiles out support for 1698 system calls related to UIDs, GIDs, and capabilities, such as setuid, 1699 setgid, and capset. 1700 1701 If unsure, say Y here. 1702 1703config SGETMASK_SYSCALL 1704 bool "sgetmask/ssetmask syscalls support" if EXPERT 1705 default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH 1706 help 1707 sys_sgetmask and sys_ssetmask are obsolete system calls 1708 no longer supported in libc but still enabled by default in some 1709 architectures. 1710 1711 If unsure, leave the default option here. 1712 1713config FHANDLE 1714 bool "open by fhandle syscalls" if EXPERT 1715 select EXPORTFS 1716 default y 1717 help 1718 If you say Y here, a user level program will be able to map 1719 file names to handle and then later use the handle for 1720 different file system operations. This is useful in implementing 1721 userspace file servers, which now track files using handles instead 1722 of names. The handle would remain the same even if file names 1723 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 1724 syscalls. 1725 1726config POSIX_TIMERS 1727 bool "Posix Clocks & timers" if EXPERT 1728 default y 1729 help 1730 This includes native support for POSIX timers to the kernel. 1731 Some embedded systems have no use for them and therefore they 1732 can be configured out to reduce the size of the kernel image. 1733 1734 When this option is disabled, the following syscalls won't be 1735 available: timer_create, timer_gettime: timer_getoverrun, 1736 timer_settime, timer_delete, clock_adjtime, getitimer, 1737 setitimer, alarm. Furthermore, the clock_settime, clock_gettime, 1738 clock_getres and clock_nanosleep syscalls will be limited to 1739 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. 1740 1741 If unsure say y. 1742 1743config PRINTK 1744 default y 1745 bool "Enable support for printk" if EXPERT 1746 select IRQ_WORK 1747 help 1748 This option enables normal printk support. Removing it 1749 eliminates most of the message strings from the kernel image 1750 and makes the kernel more or less silent. As this makes it 1751 very difficult to diagnose system problems, saying N here is 1752 strongly discouraged. 1753 1754config PRINTK_RINGBUFFER_KUNIT_TEST 1755 tristate "KUnit Test for the printk ringbuffer" if !KUNIT_ALL_TESTS 1756 depends on PRINTK && KUNIT 1757 default KUNIT_ALL_TESTS 1758 help 1759 This builds the printk ringbuffer KUnit test suite. 1760 1761 For more information on KUnit and unit tests in general, please refer 1762 to the KUnit documentation. 1763 1764 If unsure, say N. 1765 1766config BUG 1767 bool "BUG() support" if EXPERT 1768 default y 1769 help 1770 Disabling this option eliminates support for BUG and WARN, reducing 1771 the size of your kernel image and potentially quietly ignoring 1772 numerous fatal conditions. You should only consider disabling this 1773 option for embedded systems with no facilities for reporting errors. 1774 Just say Y. 1775 1776config ELF_CORE 1777 depends on COREDUMP 1778 default y 1779 bool "Enable ELF core dumps" if EXPERT 1780 help 1781 Enable support for generating core dumps. Disabling saves about 4k. 1782 1783 1784config PCSPKR_PLATFORM 1785 bool "Enable PC-Speaker support" if EXPERT 1786 depends on HAVE_PCSPKR_PLATFORM 1787 select I8253_LOCK 1788 default y 1789 help 1790 This option allows to disable the internal PC-Speaker 1791 support, saving some memory. 1792 1793config BASE_SMALL 1794 bool "Enable smaller-sized data structures for core" if EXPERT 1795 help 1796 Enabling this option reduces the size of miscellaneous core 1797 kernel data structures. This saves memory on small machines, 1798 but may reduce performance. 1799 1800config FUTEX 1801 bool "Enable futex support" if EXPERT 1802 depends on !(SPARC32 && SMP) 1803 default y 1804 imply RT_MUTEXES 1805 help 1806 Disabling this option will cause the kernel to be built without 1807 support for "fast userspace mutexes". The resulting kernel may not 1808 run glibc-based applications correctly. 1809 1810config FUTEX_PI 1811 bool 1812 depends on FUTEX && RT_MUTEXES 1813 default y 1814 1815config FUTEX_PRIVATE_HASH 1816 bool 1817 depends on FUTEX && !BASE_SMALL && MMU 1818 default y 1819 1820config FUTEX_MPOL 1821 bool 1822 depends on FUTEX && NUMA 1823 default y 1824 1825config EPOLL 1826 bool "Enable eventpoll support" if EXPERT 1827 default y 1828 help 1829 Disabling this option will cause the kernel to be built without 1830 support for epoll family of system calls. 1831 1832config SIGNALFD 1833 bool "Enable signalfd() system call" if EXPERT 1834 default y 1835 help 1836 Enable the signalfd() system call that allows to receive signals 1837 on a file descriptor. 1838 1839 If unsure, say Y. 1840 1841config TIMERFD 1842 bool "Enable timerfd() system call" if EXPERT 1843 default y 1844 help 1845 Enable the timerfd() system call that allows to receive timer 1846 events on a file descriptor. 1847 1848 If unsure, say Y. 1849 1850config EVENTFD 1851 bool "Enable eventfd() system call" if EXPERT 1852 default y 1853 help 1854 Enable the eventfd() system call that allows to receive both 1855 kernel notification (ie. KAIO) or userspace notifications. 1856 1857 If unsure, say Y. 1858 1859config SHMEM 1860 bool "Use full shmem filesystem" if EXPERT 1861 default y 1862 depends on MMU 1863 help 1864 The shmem is an internal filesystem used to manage shared memory. 1865 It is backed by swap and manages resource limits. It is also exported 1866 to userspace as tmpfs if TMPFS is enabled. Disabling this 1867 option replaces shmem and tmpfs with the much simpler ramfs code, 1868 which may be appropriate on small systems without swap. 1869 1870config AIO 1871 bool "Enable AIO support" if EXPERT 1872 default y 1873 help 1874 This option enables POSIX asynchronous I/O which may by used 1875 by some high performance threaded applications. Disabling 1876 this option saves about 7k. 1877 1878config IO_URING 1879 bool "Enable IO uring support" if EXPERT 1880 select IO_WQ 1881 default y 1882 help 1883 This option enables support for the io_uring interface, enabling 1884 applications to submit and complete IO through submission and 1885 completion rings that are shared between the kernel and application. 1886 1887config GCOV_PROFILE_URING 1888 bool "Enable GCOV profiling on the io_uring subsystem" 1889 depends on IO_URING && GCOV_KERNEL 1890 help 1891 Enable GCOV profiling on the io_uring subsystem, to facilitate 1892 code coverage testing. 1893 1894 If unsure, say N. 1895 1896 Note that this will have a negative impact on the performance of 1897 the io_uring subsystem, hence this should only be enabled for 1898 specific test purposes. 1899 1900config IO_URING_MOCK_FILE 1901 tristate "Enable io_uring mock files (Experimental)" if EXPERT 1902 default n 1903 depends on IO_URING 1904 help 1905 Enable mock files for io_uring subststem testing. The ABI might 1906 still change, so it's still experimental and should only be enabled 1907 for specific test purposes. 1908 1909 If unsure, say N. 1910 1911config ADVISE_SYSCALLS 1912 bool "Enable madvise/fadvise syscalls" if EXPERT 1913 default y 1914 help 1915 This option enables the madvise and fadvise syscalls, used by 1916 applications to advise the kernel about their future memory or file 1917 usage, improving performance. If building an embedded system where no 1918 applications use these syscalls, you can disable this option to save 1919 space. 1920 1921config MEMBARRIER 1922 bool "Enable membarrier() system call" if EXPERT 1923 default y 1924 help 1925 Enable the membarrier() system call that allows issuing memory 1926 barriers across all running threads, which can be used to distribute 1927 the cost of user-space memory barriers asymmetrically by transforming 1928 pairs of memory barriers into pairs consisting of membarrier() and a 1929 compiler barrier. 1930 1931 If unsure, say Y. 1932 1933config KCMP 1934 bool "Enable kcmp() system call" if EXPERT 1935 help 1936 Enable the kernel resource comparison system call. It provides 1937 user-space with the ability to compare two processes to see if they 1938 share a common resource, such as a file descriptor or even virtual 1939 memory space. 1940 1941 If unsure, say N. 1942 1943config RSEQ 1944 bool "Enable rseq() system call" if EXPERT 1945 default y 1946 depends on HAVE_RSEQ 1947 select MEMBARRIER 1948 help 1949 Enable the restartable sequences system call. It provides a 1950 user-space cache for the current CPU number value, which 1951 speeds up getting the current CPU number from user-space, 1952 as well as an ABI to speed up user-space operations on 1953 per-CPU data. 1954 1955 If unsure, say Y. 1956 1957config RSEQ_SLICE_EXTENSION 1958 bool "Enable rseq-based time slice extension mechanism" 1959 depends on RSEQ && HIGH_RES_TIMERS && GENERIC_ENTRY && HAVE_GENERIC_TIF_BITS 1960 help 1961 Allows userspace to request a limited time slice extension when 1962 returning from an interrupt to user space via the RSEQ shared 1963 data ABI. If granted, that allows to complete a critical section, 1964 so that other threads are not stuck on a conflicted resource, 1965 while the task is scheduled out. 1966 1967 If unsure, say N. 1968 1969config RSEQ_STATS 1970 default n 1971 bool "Enable lightweight statistics of restartable sequences" if EXPERT 1972 depends on RSEQ && DEBUG_FS 1973 help 1974 Enable lightweight counters which expose information about the 1975 frequency of RSEQ operations via debugfs. Mostly interesting for 1976 kernel debugging or performance analysis. While lightweight it's 1977 still adding code into the user/kernel mode transitions. 1978 1979 If unsure, say N. 1980 1981config RSEQ_DEBUG_DEFAULT_ENABLE 1982 default n 1983 bool "Enable restartable sequences debug mode by default" if EXPERT 1984 depends on RSEQ 1985 help 1986 This enables the static branch for debug mode of restartable 1987 sequences. 1988 1989 This also can be controlled on the kernel command line via the 1990 command line parameter "rseq_debug=0/1" and through debugfs. 1991 1992 If unsure, say N. 1993 1994config DEBUG_RSEQ 1995 default n 1996 bool "Enable debugging of rseq() system call" if EXPERT 1997 depends on RSEQ && DEBUG_KERNEL && !GENERIC_ENTRY 1998 select RSEQ_DEBUG_DEFAULT_ENABLE 1999 help 2000 Enable extra debugging checks for the rseq system call. 2001 2002 If unsure, say N. 2003 2004config CACHESTAT_SYSCALL 2005 bool "Enable cachestat() system call" if EXPERT 2006 default y 2007 help 2008 Enable the cachestat system call, which queries the page cache 2009 statistics of a file (number of cached pages, dirty pages, 2010 pages marked for writeback, (recently) evicted pages). 2011 2012 If unsure say Y here. 2013 2014config KALLSYMS 2015 bool "Load all symbols for debugging/ksymoops" if EXPERT 2016 default y 2017 help 2018 Say Y here to let the kernel print out symbolic crash information and 2019 symbolic stack backtraces. This increases the size of the kernel 2020 somewhat, as all symbols have to be loaded into the kernel image. 2021 2022config KALLSYMS_SELFTEST 2023 bool "Test the basic functions and performance of kallsyms" 2024 depends on KALLSYMS 2025 default n 2026 help 2027 Test the basic functions and performance of some interfaces, such as 2028 kallsyms_lookup_name. It also calculates the compression rate of the 2029 kallsyms compression algorithm for the current symbol set. 2030 2031 Start self-test automatically after system startup. Suggest executing 2032 "dmesg | grep kallsyms_selftest" to collect test results. "finish" is 2033 displayed in the last line, indicating that the test is complete. 2034 2035config KALLSYMS_ALL 2036 bool "Include all symbols in kallsyms" 2037 depends on DEBUG_KERNEL && KALLSYMS 2038 help 2039 Normally kallsyms only contains the symbols of functions for nicer 2040 OOPS messages and backtraces (i.e., symbols from the text and inittext 2041 sections). This is sufficient for most cases. And only if you want to 2042 enable kernel live patching, or other less common use cases (e.g., 2043 when a debugger is used) all symbols are required (i.e., names of 2044 variables from the data sections, etc). 2045 2046 This option makes sure that all symbols are loaded into the kernel 2047 image (i.e., symbols from all sections) in cost of increased kernel 2048 size (depending on the kernel configuration, it may be 300KiB or 2049 something like this). 2050 2051 Say N unless you really need all symbols, or kernel live patching. 2052 2053# end of the "standard kernel features (expert users)" menu 2054 2055config ARCH_HAS_MEMBARRIER_CALLBACKS 2056 bool 2057 2058config ARCH_HAS_MEMBARRIER_SYNC_CORE 2059 bool 2060 2061config ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 2062 bool 2063 help 2064 Control MSEAL_SYSTEM_MAPPINGS access based on architecture. 2065 2066 A 64-bit kernel is required for the memory sealing feature. 2067 No specific hardware features from the CPU are needed. 2068 2069 To enable this feature, the architecture needs to update their 2070 special mappings calls to include the sealing flag and confirm 2071 that it doesn't unmap/remap system mappings during the life 2072 time of the process. The existence of this flag for an architecture 2073 implies that it does not require the remapping of the system 2074 mappings during process lifetime, so sealing these mappings is safe 2075 from a kernel perspective. 2076 2077 After the architecture enables this, a distribution can set 2078 CONFIG_MSEAL_SYSTEM_MAPPING to manage access to the feature. 2079 2080 For complete descriptions of memory sealing, please see 2081 Documentation/userspace-api/mseal.rst 2082 2083config HAVE_PERF_EVENTS 2084 bool 2085 help 2086 See tools/perf/design.txt for details. 2087 2088config GUEST_PERF_EVENTS 2089 bool 2090 depends on HAVE_PERF_EVENTS 2091 2092config PERF_GUEST_MEDIATED_PMU 2093 bool 2094 depends on GUEST_PERF_EVENTS 2095 2096config PERF_USE_VMALLOC 2097 bool 2098 help 2099 See tools/perf/design.txt for details 2100 2101menu "Kernel Performance Events And Counters" 2102 2103config PERF_EVENTS 2104 bool "Kernel performance events and counters" 2105 default y if PROFILING 2106 depends on HAVE_PERF_EVENTS 2107 select IRQ_WORK 2108 help 2109 Enable kernel support for various performance events provided 2110 by software and hardware. 2111 2112 Software events are supported either built-in or via the 2113 use of generic tracepoints. 2114 2115 Most modern CPUs support performance events via performance 2116 counter registers. These registers count the number of certain 2117 types of hw events: such as instructions executed, cachemisses 2118 suffered, or branches mis-predicted - without slowing down the 2119 kernel or applications. These registers can also trigger interrupts 2120 when a threshold number of events have passed - and can thus be 2121 used to profile the code that runs on that CPU. 2122 2123 The Linux Performance Event subsystem provides an abstraction of 2124 these software and hardware event capabilities, available via a 2125 system call and used by the "perf" utility in tools/perf/. It 2126 provides per task and per CPU counters, and it provides event 2127 capabilities on top of those. 2128 2129 Say Y if unsure. 2130 2131config DEBUG_PERF_USE_VMALLOC 2132 default n 2133 bool "Debug: use vmalloc to back perf mmap() buffers" 2134 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC 2135 select PERF_USE_VMALLOC 2136 help 2137 Use vmalloc memory to back perf mmap() buffers. 2138 2139 Mostly useful for debugging the vmalloc code on platforms 2140 that don't require it. 2141 2142 Say N if unsure. 2143 2144endmenu 2145 2146config SYSTEM_DATA_VERIFICATION 2147 def_bool n 2148 select SYSTEM_TRUSTED_KEYRING 2149 select KEYS 2150 select CRYPTO 2151 select CRYPTO_RSA 2152 select ASYMMETRIC_KEY_TYPE 2153 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 2154 select ASN1 2155 select OID_REGISTRY 2156 select X509_CERTIFICATE_PARSER 2157 select PKCS7_MESSAGE_PARSER 2158 help 2159 Provide PKCS#7 message verification using the contents of the system 2160 trusted keyring to provide public keys. This then can be used for 2161 module verification, kexec image verification and firmware blob 2162 verification. 2163 2164config PROFILING 2165 bool "Profiling support" 2166 help 2167 Say Y here to enable the extended profiling support mechanisms used 2168 by profilers. 2169 2170config RUST 2171 bool "Rust support" 2172 depends on HAVE_RUST 2173 depends on RUST_IS_AVAILABLE 2174 select EXTENDED_MODVERSIONS if MODVERSIONS 2175 depends on !MODVERSIONS || GENDWARFKSYMS 2176 depends on !GCC_PLUGIN_RANDSTRUCT 2177 depends on !RANDSTRUCT 2178 depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO) 2179 depends on !CFI || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC 2180 select CFI_ICALL_NORMALIZE_INTEGERS if CFI 2181 depends on !CALL_PADDING || RUSTC_VERSION >= 108100 2182 depends on !KASAN_SW_TAGS 2183 depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300 2184 help 2185 Enables Rust support in the kernel. 2186 2187 This allows other Rust-related options, like drivers written in Rust, 2188 to be selected. 2189 2190 It is also required to be able to load external kernel modules 2191 written in Rust. 2192 2193 See Documentation/rust/ for more information. 2194 2195 If unsure, say N. 2196 2197config RUSTC_VERSION_TEXT 2198 string 2199 depends on RUST 2200 default "$(RUSTC_VERSION_TEXT)" 2201 help 2202 See `CC_VERSION_TEXT`. 2203 2204config BINDGEN_VERSION_TEXT 2205 string 2206 depends on RUST 2207 # The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0 2208 # (https://github.com/rust-lang/rust-bindgen/pull/2678) and 0.71.0 2209 # (https://github.com/rust-lang/rust-bindgen/pull/3040). It can be removed 2210 # when the minimum version is upgraded past the latter (0.69.1 and 0.71.1 2211 # both fixed the issue). 2212 default "$(shell,$(BINDGEN) --version workaround-for-0.69.0 2>/dev/null)" 2213 2214# 2215# Place an empty function call at each tracepoint site. Can be 2216# dynamically changed for a probe function. 2217# 2218config TRACEPOINTS 2219 bool 2220 select TASKS_TRACE_RCU 2221 2222source "kernel/Kconfig.kexec" 2223 2224source "kernel/liveupdate/Kconfig" 2225 2226endmenu # General setup 2227 2228source "arch/Kconfig" 2229 2230config RT_MUTEXES 2231 bool 2232 default y if PREEMPT_RT 2233 2234config MODULE_SIG_FORMAT 2235 def_bool n 2236 select SYSTEM_DATA_VERIFICATION 2237 2238source "kernel/module/Kconfig" 2239 2240config INIT_ALL_POSSIBLE 2241 bool 2242 help 2243 Back when each arch used to define their own cpu_online_mask and 2244 cpu_possible_mask, some of them chose to initialize cpu_possible_mask 2245 with all 1s, and others with all 0s. When they were centralised, 2246 it was better to provide this option than to break all the archs 2247 and have several arch maintainers pursuing me down dark alleys. 2248 2249source "block/Kconfig" 2250 2251config PREEMPT_NOTIFIERS 2252 bool 2253 2254config PADATA 2255 depends on SMP 2256 bool 2257 2258config ASN1 2259 tristate 2260 help 2261 Build a simple ASN.1 grammar compiler that produces a bytecode output 2262 that can be interpreted by the ASN.1 stream decoder and used to 2263 inform it as to what tags are to be expected in a stream and what 2264 functions to call on what tags. 2265 2266source "kernel/Kconfig.locks" 2267 2268config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 2269 bool 2270 2271config ARCH_HAS_PREPARE_SYNC_CORE_CMD 2272 bool 2273 2274config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2275 bool 2276 2277# It may be useful for an architecture to override the definitions of the 2278# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> 2279# and the COMPAT_ variants in <linux/compat.h>, in particular to use a 2280# different calling convention for syscalls. They can also override the 2281# macros for not-implemented syscalls in kernel/sys_ni.c and 2282# kernel/time/posix-stubs.c. All these overrides need to be available in 2283# <asm/syscall_wrapper.h>. 2284config ARCH_HAS_SYSCALL_WRAPPER 2285 def_bool n 2286