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