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