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 19.1.3 to avoid __bdos miscalculations 121 # https://github.com/llvm/llvm-project/pull/110497 122 # https://github.com/llvm/llvm-project/pull/112636 123 default y if CC_IS_CLANG && CLANG_VERSION >= 190103 124 # supported since gcc 15.1.0 125 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896 126 default y if CC_IS_GCC && GCC_VERSION >= 150100 127 128config CC_HAS_MULTIDIMENSIONAL_NONSTRING 129 def_bool $(success,echo 'char tag[][4] __attribute__((__nonstring__)) = { };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror) 130 131config LD_CAN_USE_KEEP_IN_OVERLAY 132 # ld.lld prior to 21.0.0 did not support KEEP within an overlay description 133 # https://github.com/llvm/llvm-project/pull/130661 134 def_bool LD_IS_BFD || LLD_VERSION >= 210000 135 136config RUSTC_HAS_COERCE_POINTEE 137 def_bool RUSTC_VERSION >= 108400 138 139config RUSTC_HAS_SPAN_FILE 140 def_bool RUSTC_VERSION >= 108800 141 142config RUSTC_HAS_UNNECESSARY_TRANSMUTES 143 def_bool RUSTC_VERSION >= 108800 144 145config RUSTC_HAS_FILE_WITH_NUL 146 def_bool RUSTC_VERSION >= 108900 147 148config PAHOLE_VERSION 149 int 150 default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE)) 151 152config CONSTRUCTORS 153 bool 154 155config IRQ_WORK 156 def_bool y if SMP 157 158config BUILDTIME_TABLE_SORT 159 bool 160 161config THREAD_INFO_IN_TASK 162 bool 163 help 164 Select this to move thread_info off the stack into task_struct. To 165 make this work, an arch will need to remove all thread_info fields 166 except flags and fix any runtime bugs. 167 168 One subtle change that will be needed is to use try_get_task_stack() 169 and put_task_stack() in save_thread_stack_tsk() and get_wchan(). 170 171menu "General setup" 172 173config BROKEN 174 bool 175 176config BROKEN_ON_SMP 177 bool 178 depends on BROKEN || !SMP 179 default y 180 181config INIT_ENV_ARG_LIMIT 182 int 183 default 32 if !UML 184 default 128 if UML 185 help 186 Maximum of each of the number of arguments and environment 187 variables passed to init from the kernel command line. 188 189config COMPILE_TEST 190 bool "Compile also drivers which will not load" 191 depends on HAS_IOMEM 192 help 193 Some drivers can be compiled on a different platform than they are 194 intended to be run on. Despite they cannot be loaded there (or even 195 when they load they cannot be used due to missing HW support), 196 developers still, opposing to distributors, might want to build such 197 drivers to compile-test them. 198 199 If you are a developer and want to build everything available, say Y 200 here. If you are a user/distributor, say N here to exclude useless 201 drivers to be distributed. 202 203config WERROR 204 bool "Compile the kernel with warnings as errors" 205 default COMPILE_TEST 206 help 207 A kernel build should not cause any compiler warnings, and this 208 enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags 209 to enforce that rule by default. Certain warnings from other tools 210 such as the linker may be upgraded to errors with this option as 211 well. 212 213 However, if you have a new (or very old) compiler or linker with odd 214 and unusual warnings, or you have some architecture with problems, 215 you may need to disable this config option in order to 216 successfully build the kernel. 217 218 If in doubt, say Y. 219 220config UAPI_HEADER_TEST 221 bool "Compile test UAPI headers" 222 depends on HEADERS_INSTALL && CC_CAN_LINK 223 help 224 Compile test headers exported to user-space to ensure they are 225 self-contained, i.e. compilable as standalone units. 226 227 If you are a developer or tester and want to ensure the exported 228 headers are self-contained, say Y here. Otherwise, choose N. 229 230config LOCALVERSION 231 string "Local version - append to kernel release" 232 help 233 Append an extra string to the end of your kernel version. 234 This will show up when you type uname, for example. 235 The string you set here will be appended after the contents of 236 any files with a filename matching localversion* in your 237 object and source tree, in that order. Your total string can 238 be a maximum of 64 characters. 239 240config LOCALVERSION_AUTO 241 bool "Automatically append version information to the version string" 242 default y 243 depends on !COMPILE_TEST 244 help 245 This will try to automatically determine if the current tree is a 246 release tree by looking for git tags that belong to the current 247 top of tree revision. 248 249 A string of the format -gxxxxxxxx will be added to the localversion 250 if a git-based tree is found. The string generated by this will be 251 appended after any matching localversion* files, and after the value 252 set in CONFIG_LOCALVERSION. 253 254 (The actual string used here is the first 12 characters produced 255 by running the command: 256 257 $ git rev-parse --verify HEAD 258 259 which is done within the script "scripts/setlocalversion".) 260 261config BUILD_SALT 262 string "Build ID Salt" 263 default "" 264 help 265 The build ID is used to link binaries and their debug info. Setting 266 this option will use the value in the calculation of the build id. 267 This is mostly useful for distributions which want to ensure the 268 build is unique between builds. It's safe to leave the default. 269 270config HAVE_KERNEL_GZIP 271 bool 272 273config HAVE_KERNEL_BZIP2 274 bool 275 276config HAVE_KERNEL_LZMA 277 bool 278 279config HAVE_KERNEL_XZ 280 bool 281 282config HAVE_KERNEL_LZO 283 bool 284 285config HAVE_KERNEL_LZ4 286 bool 287 288config HAVE_KERNEL_ZSTD 289 bool 290 291config HAVE_KERNEL_UNCOMPRESSED 292 bool 293 294choice 295 prompt "Kernel compression mode" 296 default KERNEL_GZIP 297 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 298 help 299 The linux kernel is a kind of self-extracting executable. 300 Several compression algorithms are available, which differ 301 in efficiency, compression and decompression speed. 302 Compression speed is only relevant when building a kernel. 303 Decompression speed is relevant at each boot. 304 305 If you have any problems with bzip2 or lzma compressed 306 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 307 version of this functionality (bzip2 only), for 2.4, was 308 supplied by Christian Ludwig) 309 310 High compression options are mostly useful for users, who 311 are low on disk space (embedded systems), but for whom ram 312 size matters less. 313 314 If in doubt, select 'gzip' 315 316config KERNEL_GZIP 317 bool "Gzip" 318 depends on HAVE_KERNEL_GZIP 319 help 320 The old and tried gzip compression. It provides a good balance 321 between compression ratio and decompression speed. 322 323config KERNEL_BZIP2 324 bool "Bzip2" 325 depends on HAVE_KERNEL_BZIP2 326 help 327 Its compression ratio and speed is intermediate. 328 Decompression speed is slowest among the choices. The kernel 329 size is about 10% smaller with bzip2, in comparison to gzip. 330 Bzip2 uses a large amount of memory. For modern kernels you 331 will need at least 8MB RAM or more for booting. 332 333config KERNEL_LZMA 334 bool "LZMA" 335 depends on HAVE_KERNEL_LZMA 336 help 337 This compression algorithm's ratio is best. Decompression speed 338 is between gzip and bzip2. Compression is slowest. 339 The kernel size is about 33% smaller with LZMA in comparison to gzip. 340 341config KERNEL_XZ 342 bool "XZ" 343 depends on HAVE_KERNEL_XZ 344 help 345 XZ uses the LZMA2 algorithm and instruction set specific 346 BCJ filters which can improve compression ratio of executable 347 code. The size of the kernel is about 30% smaller with XZ in 348 comparison to gzip. On architectures for which there is a BCJ 349 filter (i386, x86_64, ARM, ARM64, RISC-V, big endian PowerPC, 350 and SPARC), XZ will create a few percent smaller kernel than 351 plain LZMA. 352 353 The speed is about the same as with LZMA: The decompression 354 speed of XZ is better than that of bzip2 but worse than gzip 355 and LZO. Compression is slow. 356 357config KERNEL_LZO 358 bool "LZO" 359 depends on HAVE_KERNEL_LZO 360 help 361 Its compression ratio is the poorest among the choices. The kernel 362 size is about 10% bigger than gzip; however its speed 363 (both compression and decompression) is the fastest. 364 365config KERNEL_LZ4 366 bool "LZ4" 367 depends on HAVE_KERNEL_LZ4 368 help 369 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. 370 A preliminary version of LZ4 de/compression tool is available at 371 <https://code.google.com/p/lz4/>. 372 373 Its compression ratio is worse than LZO. The size of the kernel 374 is about 8% bigger than LZO. But the decompression speed is 375 faster than LZO. 376 377config KERNEL_ZSTD 378 bool "ZSTD" 379 depends on HAVE_KERNEL_ZSTD 380 help 381 ZSTD is a compression algorithm targeting intermediate compression 382 with fast decompression speed. It will compress better than GZIP and 383 decompress around the same speed as LZO, but slower than LZ4. You 384 will need at least 192 KB RAM or more for booting. The zstd command 385 line tool is required for compression. 386 387config KERNEL_UNCOMPRESSED 388 bool "None" 389 depends on HAVE_KERNEL_UNCOMPRESSED 390 help 391 Produce uncompressed kernel image. This option is usually not what 392 you want. It is useful for debugging the kernel in slow simulation 393 environments, where decompressing and moving the kernel is awfully 394 slow. This option allows early boot code to skip the decompressor 395 and jump right at uncompressed kernel image. 396 397endchoice 398 399config DEFAULT_INIT 400 string "Default init path" 401 default "" 402 help 403 This option determines the default init for the system if no init= 404 option is passed on the kernel command line. If the requested path is 405 not present, we will still then move on to attempting further 406 locations (e.g. /sbin/init, etc). If this is empty, we will just use 407 the fallback list when init= is not passed. 408 409config DEFAULT_HOSTNAME 410 string "Default hostname" 411 default "(none)" 412 help 413 This option determines the default system hostname before userspace 414 calls sethostname(2). The kernel traditionally uses "(none)" here, 415 but you may wish to use a different default here to make a minimal 416 system more usable with less configuration. 417 418config SYSVIPC 419 bool "System V IPC" 420 help 421 Inter Process Communication is a suite of library functions and 422 system calls which let processes (running programs) synchronize and 423 exchange information. It is generally considered to be a good thing, 424 and some programs won't run unless you say Y here. In particular, if 425 you want to run the DOS emulator dosemu under Linux (read the 426 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 427 you'll need to say Y here. 428 429 You can find documentation about IPC with "info ipc" and also in 430 section 6.4 of the Linux Programmer's Guide, available from 431 <http://www.tldp.org/guides.html>. 432 433config SYSVIPC_SYSCTL 434 bool 435 depends on SYSVIPC 436 depends on SYSCTL 437 default y 438 439config SYSVIPC_COMPAT 440 def_bool y 441 depends on COMPAT && SYSVIPC 442 443config POSIX_MQUEUE 444 bool "POSIX Message Queues" 445 depends on NET 446 help 447 POSIX variant of message queues is a part of IPC. In POSIX message 448 queues every message has a priority which decides about succession 449 of receiving it by a process. If you want to compile and run 450 programs written e.g. for Solaris with use of its POSIX message 451 queues (functions mq_*) say Y here. 452 453 POSIX message queues are visible as a filesystem called 'mqueue' 454 and can be mounted somewhere if you want to do filesystem 455 operations on message queues. 456 457 If unsure, say Y. 458 459config POSIX_MQUEUE_SYSCTL 460 bool 461 depends on POSIX_MQUEUE 462 depends on SYSCTL 463 default y 464 465config WATCH_QUEUE 466 bool "General notification queue" 467 default n 468 help 469 470 This is a general notification queue for the kernel to pass events to 471 userspace by splicing them into pipes. It can be used in conjunction 472 with watches for key/keyring change notifications and device 473 notifications. 474 475 See Documentation/core-api/watch_queue.rst 476 477config CROSS_MEMORY_ATTACH 478 bool "Enable process_vm_readv/writev syscalls" 479 depends on MMU 480 default y 481 help 482 Enabling this option adds the system calls process_vm_readv and 483 process_vm_writev which allow a process with the correct privileges 484 to directly read from or write to another process' address space. 485 See the man page for more details. 486 487config AUDIT 488 bool "Auditing support" 489 depends on NET 490 help 491 Enable auditing infrastructure that can be used with another 492 kernel subsystem, such as SELinux (which requires this for 493 logging of avc messages output). System call auditing is included 494 on architectures which support it. 495 496config HAVE_ARCH_AUDITSYSCALL 497 bool 498 499config AUDITSYSCALL 500 def_bool y 501 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL 502 select FSNOTIFY 503 504source "kernel/irq/Kconfig" 505source "kernel/time/Kconfig" 506source "kernel/bpf/Kconfig" 507source "kernel/Kconfig.preempt" 508 509menu "CPU/Task time and stats accounting" 510 511config VIRT_CPU_ACCOUNTING 512 bool 513 514choice 515 prompt "Cputime accounting" 516 default TICK_CPU_ACCOUNTING 517 518# Kind of a stub config for the pure tick based cputime accounting 519config TICK_CPU_ACCOUNTING 520 bool "Simple tick based cputime accounting" 521 depends on !S390 && !NO_HZ_FULL 522 help 523 This is the basic tick based cputime accounting that maintains 524 statistics about user, system and idle time spent on per jiffies 525 granularity. 526 527 If unsure, say Y. 528 529config VIRT_CPU_ACCOUNTING_NATIVE 530 bool "Deterministic task and CPU time accounting" 531 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL 532 select VIRT_CPU_ACCOUNTING 533 help 534 Select this option to enable more accurate task and CPU time 535 accounting. This is done by reading a CPU counter on each 536 kernel entry and exit and on transitions within the kernel 537 between system, softirq and hardirq state, so there is a 538 small performance impact. In the case of s390 or IBM POWER > 5, 539 this also enables accounting of stolen time on logically-partitioned 540 systems. 541 542config VIRT_CPU_ACCOUNTING_GEN 543 bool "Full dynticks CPU time accounting" 544 depends on HAVE_CONTEXT_TRACKING_USER 545 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN 546 depends on GENERIC_CLOCKEVENTS 547 select VIRT_CPU_ACCOUNTING 548 select CONTEXT_TRACKING_USER 549 help 550 Select this option to enable task and CPU time accounting on full 551 dynticks systems. This accounting is implemented by watching every 552 kernel-user boundaries using the context tracking subsystem. 553 The accounting is thus performed at the expense of some significant 554 overhead. 555 556 For now this is only useful if you are working on the full 557 dynticks subsystem development. 558 559 If unsure, say N. 560 561endchoice 562 563config IRQ_TIME_ACCOUNTING 564 bool "Fine granularity task level IRQ time accounting" 565 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE 566 help 567 Select this option to enable fine granularity task irq time 568 accounting. This is done by reading a timestamp on each 569 transitions between softirq and hardirq state, so there can be a 570 small performance impact. 571 572 If in doubt, say N here. 573 574config HAVE_SCHED_AVG_IRQ 575 def_bool y 576 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING 577 depends on SMP 578 579config SCHED_HW_PRESSURE 580 bool 581 default y if ARM && ARM_CPU_TOPOLOGY 582 default y if ARM64 583 depends on SMP 584 depends on CPU_FREQ_THERMAL 585 help 586 Select this option to enable HW pressure accounting in the 587 scheduler. HW pressure is the value conveyed to the scheduler 588 that reflects the reduction in CPU compute capacity resulted from 589 HW throttling. HW throttling occurs when the performance of 590 a CPU is capped due to high operating temperatures as an example. 591 592 If selected, the scheduler will be able to balance tasks accordingly, 593 i.e. put less load on throttled CPUs than on non/less throttled ones. 594 595 This requires the architecture to implement 596 arch_update_hw_pressure() and arch_scale_thermal_pressure(). 597 598config BSD_PROCESS_ACCT 599 bool "BSD Process Accounting" 600 depends on MULTIUSER 601 help 602 If you say Y here, a user level program will be able to instruct the 603 kernel (via a special system call) to write process accounting 604 information to a file: whenever a process exits, information about 605 that process will be appended to the file by the kernel. The 606 information includes things such as creation time, owning user, 607 command name, memory usage, controlling terminal etc. (the complete 608 list is in the struct acct in <file:include/linux/acct.h>). It is 609 up to the user level program to do useful things with this 610 information. This is generally a good idea, so say Y. 611 612config BSD_PROCESS_ACCT_V3 613 bool "BSD Process Accounting version 3 file format" 614 depends on BSD_PROCESS_ACCT 615 default n 616 help 617 If you say Y here, the process accounting information is written 618 in a new file format that also logs the process IDs of each 619 process and its parent. Note that this file format is incompatible 620 with previous v0/v1/v2 file formats, so you will need updated tools 621 for processing it. A preliminary version of these tools is available 622 at <http://www.gnu.org/software/acct/>. 623 624config TASKSTATS 625 bool "Export task/process statistics through netlink" 626 depends on NET 627 depends on MULTIUSER 628 default n 629 help 630 Export selected statistics for tasks/processes through the 631 generic netlink interface. Unlike BSD process accounting, the 632 statistics are available during the lifetime of tasks/processes as 633 responses to commands. Like BSD accounting, they are sent to user 634 space on task exit. 635 636 Say N if unsure. 637 638config TASK_DELAY_ACCT 639 bool "Enable per-task delay accounting" 640 depends on TASKSTATS 641 select SCHED_INFO 642 help 643 Collect information on time spent by a task waiting for system 644 resources like cpu, synchronous block I/O completion and swapping 645 in pages. Such statistics can help in setting a task's priorities 646 relative to other tasks for cpu, io, rss limits etc. 647 648 Say N if unsure. 649 650config TASK_XACCT 651 bool "Enable extended accounting over taskstats" 652 depends on TASKSTATS 653 help 654 Collect extended task accounting data and send the data 655 to userland for processing over the taskstats interface. 656 657 Say N if unsure. 658 659config TASK_IO_ACCOUNTING 660 bool "Enable per-task storage I/O accounting" 661 depends on TASK_XACCT 662 help 663 Collect information on the number of bytes of storage I/O which this 664 task has caused. 665 666 Say N if unsure. 667 668config PSI 669 bool "Pressure stall information tracking" 670 select KERNFS 671 help 672 Collect metrics that indicate how overcommitted the CPU, memory, 673 and IO capacity are in the system. 674 675 If you say Y here, the kernel will create /proc/pressure/ with the 676 pressure statistics files cpu, memory, and io. These will indicate 677 the share of walltime in which some or all tasks in the system are 678 delayed due to contention of the respective resource. 679 680 In kernels with cgroup support, cgroups (cgroup2 only) will 681 have cpu.pressure, memory.pressure, and io.pressure files, 682 which aggregate pressure stalls for the grouped tasks only. 683 684 For more details see Documentation/accounting/psi.rst. 685 686 Say N if unsure. 687 688config PSI_DEFAULT_DISABLED 689 bool "Require boot parameter to enable pressure stall information tracking" 690 default n 691 depends on PSI 692 help 693 If set, pressure stall information tracking will be disabled 694 per default but can be enabled through passing psi=1 on the 695 kernel commandline during boot. 696 697 This feature adds some code to the task wakeup and sleep 698 paths of the scheduler. The overhead is too low to affect 699 common scheduling-intense workloads in practice (such as 700 webservers, memcache), but it does show up in artificial 701 scheduler stress tests, such as hackbench. 702 703 If you are paranoid and not sure what the kernel will be 704 used for, say Y. 705 706 Say N if unsure. 707 708endmenu # "CPU/Task time and stats accounting" 709 710config CPU_ISOLATION 711 bool "CPU isolation" 712 depends on SMP 713 default y 714 help 715 Make sure that CPUs running critical tasks are not disturbed by 716 any source of "noise" such as unbound workqueues, timers, kthreads... 717 Unbound jobs get offloaded to housekeeping CPUs. This is driven by 718 the "isolcpus=" boot parameter. 719 720 Say Y if unsure. 721 722source "kernel/rcu/Kconfig" 723 724config IKCONFIG 725 tristate "Kernel .config support" 726 help 727 This option enables the complete Linux kernel ".config" file 728 contents to be saved in the kernel. It provides documentation 729 of which kernel options are used in a running kernel or in an 730 on-disk kernel. This information can be extracted from the kernel 731 image file with the script scripts/extract-ikconfig and used as 732 input to rebuild the current kernel or to build another kernel. 733 It can also be extracted from a running kernel by reading 734 /proc/config.gz if enabled (below). 735 736config IKCONFIG_PROC 737 bool "Enable access to .config through /proc/config.gz" 738 depends on IKCONFIG && PROC_FS 739 help 740 This option enables access to the kernel configuration file 741 through /proc/config.gz. 742 743config IKHEADERS 744 tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz" 745 depends on SYSFS 746 help 747 This option enables access to the in-kernel headers that are generated during 748 the build process. These can be used to build eBPF tracing programs, 749 or similar programs. If you build the headers as a module, a module called 750 kheaders.ko is built which can be loaded on-demand to get access to headers. 751 752config LOG_BUF_SHIFT 753 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 754 range 12 25 755 default 17 756 depends on PRINTK 757 help 758 Select the minimal kernel log buffer size as a power of 2. 759 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config 760 parameter, see below. Any higher size also might be forced 761 by "log_buf_len" boot parameter. 762 763 Examples: 764 17 => 128 KB 765 16 => 64 KB 766 15 => 32 KB 767 14 => 16 KB 768 13 => 8 KB 769 12 => 4 KB 770 771config LOG_CPU_MAX_BUF_SHIFT 772 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" 773 depends on SMP 774 range 0 21 775 default 0 if BASE_SMALL 776 default 12 777 depends on PRINTK 778 help 779 This option allows to increase the default ring buffer size 780 according to the number of CPUs. The value defines the contribution 781 of each CPU as a power of 2. The used space is typically only few 782 lines however it might be much more when problems are reported, 783 e.g. backtraces. 784 785 The increased size means that a new buffer has to be allocated and 786 the original static one is unused. It makes sense only on systems 787 with more CPUs. Therefore this value is used only when the sum of 788 contributions is greater than the half of the default kernel ring 789 buffer as defined by LOG_BUF_SHIFT. The default values are set 790 so that more than 16 CPUs are needed to trigger the allocation. 791 792 Also this option is ignored when "log_buf_len" kernel parameter is 793 used as it forces an exact (power of two) size of the ring buffer. 794 795 The number of possible CPUs is used for this computation ignoring 796 hotplugging making the computation optimal for the worst case 797 scenario while allowing a simple algorithm to be used from bootup. 798 799 Examples shift values and their meaning: 800 17 => 128 KB for each CPU 801 16 => 64 KB for each CPU 802 15 => 32 KB for each CPU 803 14 => 16 KB for each CPU 804 13 => 8 KB for each CPU 805 12 => 4 KB for each CPU 806 807config PRINTK_INDEX 808 bool "Printk indexing debugfs interface" 809 depends on PRINTK && DEBUG_FS 810 help 811 Add support for indexing of all printk formats known at compile time 812 at <debugfs>/printk/index/<module>. 813 814 This can be used as part of maintaining daemons which monitor 815 /dev/kmsg, as it permits auditing the printk formats present in a 816 kernel, allowing detection of cases where monitored printks are 817 changed or no longer present. 818 819 There is no additional runtime cost to printk with this enabled. 820 821# 822# Architectures with an unreliable sched_clock() should select this: 823# 824config HAVE_UNSTABLE_SCHED_CLOCK 825 bool 826 827config GENERIC_SCHED_CLOCK 828 bool 829 830menu "Scheduler features" 831 832config UCLAMP_TASK 833 bool "Enable utilization clamping for RT/FAIR tasks" 834 depends on CPU_FREQ_GOV_SCHEDUTIL 835 help 836 This feature enables the scheduler to track the clamped utilization 837 of each CPU based on RUNNABLE tasks scheduled on that CPU. 838 839 With this option, the user can specify the min and max CPU 840 utilization allowed for RUNNABLE tasks. The max utilization defines 841 the maximum frequency a task should use while the min utilization 842 defines the minimum frequency it should use. 843 844 Both min and max utilization clamp values are hints to the scheduler, 845 aiming at improving its frequency selection policy, but they do not 846 enforce or grant any specific bandwidth for tasks. 847 848 If in doubt, say N. 849 850config UCLAMP_BUCKETS_COUNT 851 int "Number of supported utilization clamp buckets" 852 range 5 20 853 default 5 854 depends on UCLAMP_TASK 855 help 856 Defines the number of clamp buckets to use. The range of each bucket 857 will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the 858 number of clamp buckets the finer their granularity and the higher 859 the precision of clamping aggregation and tracking at run-time. 860 861 For example, with the minimum configuration value we will have 5 862 clamp buckets tracking 20% utilization each. A 25% boosted tasks will 863 be refcounted in the [20..39]% bucket and will set the bucket clamp 864 effective value to 25%. 865 If a second 30% boosted task should be co-scheduled on the same CPU, 866 that task will be refcounted in the same bucket of the first task and 867 it will boost the bucket clamp effective value to 30%. 868 The clamp effective value of a bucket is reset to its nominal value 869 (20% in the example above) when there are no more tasks refcounted in 870 that bucket. 871 872 An additional boost/capping margin can be added to some tasks. In the 873 example above the 25% task will be boosted to 30% until it exits the 874 CPU. If that should be considered not acceptable on certain systems, 875 it's always possible to reduce the margin by increasing the number of 876 clamp buckets to trade off used memory for run-time tracking 877 precision. 878 879 If in doubt, use the default value. 880 881config SCHED_PROXY_EXEC 882 bool "Proxy Execution" 883 # Avoid some build failures w/ PREEMPT_RT until it can be fixed 884 depends on !PREEMPT_RT 885 # Need to investigate how to inform sched_ext of split contexts 886 depends on !SCHED_CLASS_EXT 887 # Not particularly useful until we get to multi-rq proxying 888 depends on EXPERT 889 help 890 This option enables proxy execution, a mechanism for mutex-owning 891 tasks to inherit the scheduling context of higher priority waiters. 892 893endmenu 894 895# 896# For architectures that want to enable the support for NUMA-affine scheduler 897# balancing logic: 898# 899config ARCH_SUPPORTS_NUMA_BALANCING 900 bool 901 902# 903# For architectures that prefer to flush all TLBs after a number of pages 904# are unmapped instead of sending one IPI per page to flush. The architecture 905# must provide guarantees on what happens if a clean TLB cache entry is 906# written after the unmap. Details are in mm/rmap.c near the check for 907# should_defer_flush. The architecture should also consider if the full flush 908# and the refill costs are offset by the savings of sending fewer IPIs. 909config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 910 bool 911 912config CC_HAS_INT128 913 def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT 914 915config CC_IMPLICIT_FALLTHROUGH 916 string 917 default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) 918 default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) 919 920# Currently, disable gcc-10+ array-bounds globally. 921# It's still broken in gcc-13, so no upper bound yet. 922config GCC10_NO_ARRAY_BOUNDS 923 def_bool y 924 925config CC_NO_ARRAY_BOUNDS 926 bool 927 default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC10_NO_ARRAY_BOUNDS 928 929# Currently, disable -Wstringop-overflow for GCC globally. 930config GCC_NO_STRINGOP_OVERFLOW 931 def_bool y 932 933config CC_NO_STRINGOP_OVERFLOW 934 bool 935 default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW 936 937config CC_STRINGOP_OVERFLOW 938 bool 939 default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW 940 941# 942# For architectures that know their GCC __int128 support is sound 943# 944config ARCH_SUPPORTS_INT128 945 bool 946 947# For architectures that (ab)use NUMA to represent different memory regions 948# all cpu-local but of different latencies, such as SuperH. 949# 950config ARCH_WANT_NUMA_VARIABLE_LOCALITY 951 bool 952 953config NUMA_BALANCING 954 bool "Memory placement aware NUMA scheduler" 955 depends on ARCH_SUPPORTS_NUMA_BALANCING 956 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY 957 depends on SMP && NUMA && MIGRATION && !PREEMPT_RT 958 help 959 This option adds support for automatic NUMA aware memory/task placement. 960 The mechanism is quite primitive and is based on migrating memory when 961 it has references to the node the task is running on. 962 963 This system will be inactive on UMA systems. 964 965config NUMA_BALANCING_DEFAULT_ENABLED 966 bool "Automatically enable NUMA aware memory/task placement" 967 default y 968 depends on NUMA_BALANCING 969 help 970 If set, automatic NUMA balancing will be enabled if running on a NUMA 971 machine. 972 973config SLAB_OBJ_EXT 974 bool 975 976menuconfig CGROUPS 977 bool "Control Group support" 978 select KERNFS 979 help 980 This option adds support for grouping sets of processes together, for 981 use with process control subsystems such as Cpusets, CFS, memory 982 controls or device isolation. 983 See 984 - Documentation/scheduler/sched-design-CFS.rst (CFS) 985 - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation 986 and resource control) 987 988 Say N if unsure. 989 990if CGROUPS 991 992config PAGE_COUNTER 993 bool 994 995config CGROUP_FAVOR_DYNMODS 996 bool "Favor dynamic modification latency reduction by default" 997 help 998 This option enables the "favordynmods" mount option by default 999 which reduces the latencies of dynamic cgroup modifications such 1000 as task migrations and controller on/offs at the cost of making 1001 hot path operations such as forks and exits more expensive. 1002 1003 Say N if unsure. 1004 1005config MEMCG 1006 bool "Memory controller" 1007 select PAGE_COUNTER 1008 select EVENTFD 1009 select SLAB_OBJ_EXT 1010 select VM_EVENT_COUNTERS 1011 help 1012 Provides control over the memory footprint of tasks in a cgroup. 1013 1014config MEMCG_NMI_UNSAFE 1015 bool 1016 depends on MEMCG 1017 depends on HAVE_NMI 1018 depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && !ARCH_HAVE_NMI_SAFE_CMPXCHG 1019 default y 1020 1021config MEMCG_NMI_SAFETY_REQUIRES_ATOMIC 1022 bool 1023 depends on MEMCG 1024 depends on HAVE_NMI 1025 depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && ARCH_HAVE_NMI_SAFE_CMPXCHG 1026 default y 1027 1028config MEMCG_V1 1029 bool "Legacy cgroup v1 memory controller" 1030 depends on MEMCG 1031 default n 1032 help 1033 Legacy cgroup v1 memory controller which has been deprecated by 1034 cgroup v2 implementation. The v1 is there for legacy applications 1035 which haven't migrated to the new cgroup v2 interface yet. If you 1036 do not have any such application then you are completely fine leaving 1037 this option disabled. 1038 1039 Please note that feature set of the legacy memory controller is likely 1040 going to shrink due to deprecation process. New deployments with v1 1041 controller are highly discouraged. 1042 1043 Say N if unsure. 1044 1045config BLK_CGROUP 1046 bool "IO controller" 1047 depends on BLOCK 1048 default n 1049 help 1050 Generic block IO controller cgroup interface. This is the common 1051 cgroup interface which should be used by various IO controlling 1052 policies. 1053 1054 Currently, CFQ IO scheduler uses it to recognize task groups and 1055 control disk bandwidth allocation (proportional time slice allocation) 1056 to such task groups. It is also used by bio throttling logic in 1057 block layer to implement upper limit in IO rates on a device. 1058 1059 This option only enables generic Block IO controller infrastructure. 1060 One needs to also enable actual IO controlling logic/policy. For 1061 enabling proportional weight division of disk bandwidth in CFQ, set 1062 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 1063 CONFIG_BLK_DEV_THROTTLING=y. 1064 1065 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information. 1066 1067config CGROUP_WRITEBACK 1068 bool 1069 depends on MEMCG && BLK_CGROUP 1070 default y 1071 1072menuconfig CGROUP_SCHED 1073 bool "CPU controller" 1074 default n 1075 help 1076 This feature lets CPU scheduler recognize task groups and control CPU 1077 bandwidth allocation to such task groups. It uses cgroups to group 1078 tasks. 1079 1080if CGROUP_SCHED 1081config GROUP_SCHED_WEIGHT 1082 def_bool n 1083 1084config GROUP_SCHED_BANDWIDTH 1085 def_bool n 1086 1087config FAIR_GROUP_SCHED 1088 bool "Group scheduling for SCHED_OTHER" 1089 depends on CGROUP_SCHED 1090 select GROUP_SCHED_WEIGHT 1091 default CGROUP_SCHED 1092 1093config CFS_BANDWIDTH 1094 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 1095 depends on FAIR_GROUP_SCHED 1096 select GROUP_SCHED_BANDWIDTH 1097 default n 1098 help 1099 This option allows users to define CPU bandwidth rates (limits) for 1100 tasks running within the fair group scheduler. Groups with no limit 1101 set are considered to be unconstrained and will run with no 1102 restriction. 1103 See Documentation/scheduler/sched-bwc.rst for more information. 1104 1105config RT_GROUP_SCHED 1106 bool "Group scheduling for SCHED_RR/FIFO" 1107 depends on CGROUP_SCHED 1108 default n 1109 help 1110 This feature lets you explicitly allocate real CPU bandwidth 1111 to task groups. If enabled, it will also make it impossible to 1112 schedule realtime tasks for non-root users until you allocate 1113 realtime bandwidth for them. 1114 See Documentation/scheduler/sched-rt-group.rst for more information. 1115 1116config RT_GROUP_SCHED_DEFAULT_DISABLED 1117 bool "Require boot parameter to enable group scheduling for SCHED_RR/FIFO" 1118 depends on RT_GROUP_SCHED 1119 default n 1120 help 1121 When set, the RT group scheduling is disabled by default. The option 1122 is in inverted form so that mere RT_GROUP_SCHED enables the group 1123 scheduling. 1124 1125 Say N if unsure. 1126 1127config EXT_GROUP_SCHED 1128 bool 1129 depends on SCHED_CLASS_EXT && CGROUP_SCHED 1130 select GROUP_SCHED_WEIGHT 1131 select GROUP_SCHED_BANDWIDTH 1132 default y 1133 1134endif #CGROUP_SCHED 1135 1136config SCHED_MM_CID 1137 def_bool y 1138 depends on SMP && RSEQ 1139 1140config UCLAMP_TASK_GROUP 1141 bool "Utilization clamping per group of tasks" 1142 depends on CGROUP_SCHED 1143 depends on UCLAMP_TASK 1144 default n 1145 help 1146 This feature enables the scheduler to track the clamped utilization 1147 of each CPU based on RUNNABLE tasks currently scheduled on that CPU. 1148 1149 When this option is enabled, the user can specify a min and max 1150 CPU bandwidth which is allowed for each single task in a group. 1151 The max bandwidth allows to clamp the maximum frequency a task 1152 can use, while the min bandwidth allows to define a minimum 1153 frequency a task will always use. 1154 1155 When task group based utilization clamping is enabled, an eventually 1156 specified task-specific clamp value is constrained by the cgroup 1157 specified clamp value. Both minimum and maximum task clamping cannot 1158 be bigger than the corresponding clamping defined at task group level. 1159 1160 If in doubt, say N. 1161 1162config CGROUP_PIDS 1163 bool "PIDs controller" 1164 help 1165 Provides enforcement of process number limits in the scope of a 1166 cgroup. Any attempt to fork more processes than is allowed in the 1167 cgroup will fail. PIDs are fundamentally a global resource because it 1168 is fairly trivial to reach PID exhaustion before you reach even a 1169 conservative kmemcg limit. As a result, it is possible to grind a 1170 system to halt without being limited by other cgroup policies. The 1171 PIDs controller is designed to stop this from happening. 1172 1173 It should be noted that organisational operations (such as attaching 1174 to a cgroup hierarchy) will *not* be blocked by the PIDs controller, 1175 since the PIDs limit only affects a process's ability to fork, not to 1176 attach to a cgroup. 1177 1178config CGROUP_RDMA 1179 bool "RDMA controller" 1180 help 1181 Provides enforcement of RDMA resources defined by IB stack. 1182 It is fairly easy for consumers to exhaust RDMA resources, which 1183 can result into resource unavailability to other consumers. 1184 RDMA controller is designed to stop this from happening. 1185 Attaching processes with active RDMA resources to the cgroup 1186 hierarchy is allowed even if can cross the hierarchy's limit. 1187 1188config CGROUP_DMEM 1189 bool "Device memory controller (DMEM)" 1190 select PAGE_COUNTER 1191 help 1192 The DMEM controller allows compatible devices to restrict device 1193 memory usage based on the cgroup hierarchy. 1194 1195 As an example, it allows you to restrict VRAM usage for applications 1196 in the DRM subsystem. 1197 1198config CGROUP_FREEZER 1199 bool "Freezer controller" 1200 help 1201 Provides a way to freeze and unfreeze all tasks in a 1202 cgroup. 1203 1204 This option affects the ORIGINAL cgroup interface. The cgroup2 memory 1205 controller includes important in-kernel memory consumers per default. 1206 1207 If you're using cgroup2, say N. 1208 1209config CGROUP_HUGETLB 1210 bool "HugeTLB controller" 1211 depends on HUGETLB_PAGE 1212 select PAGE_COUNTER 1213 default n 1214 help 1215 Provides a cgroup controller for HugeTLB pages. 1216 When you enable this, you can put a per cgroup limit on HugeTLB usage. 1217 The limit is enforced during page fault. Since HugeTLB doesn't 1218 support page reclaim, enforcing the limit at page fault time implies 1219 that, the application will get SIGBUS signal if it tries to access 1220 HugeTLB pages beyond its limit. This requires the application to know 1221 beforehand how much HugeTLB pages it would require for its use. The 1222 control group is tracked in the third page lru pointer. This means 1223 that we cannot use the controller with huge page less than 3 pages. 1224 1225config CPUSETS 1226 bool "Cpuset controller" 1227 depends on SMP 1228 select UNION_FIND 1229 help 1230 This option will let you create and manage CPUSETs which 1231 allow dynamically partitioning a system into sets of CPUs and 1232 Memory Nodes and assigning tasks to run only within those sets. 1233 This is primarily useful on large SMP or NUMA systems. 1234 1235 Say N if unsure. 1236 1237config CPUSETS_V1 1238 bool "Legacy cgroup v1 cpusets controller" 1239 depends on CPUSETS 1240 default n 1241 help 1242 Legacy cgroup v1 cpusets controller which has been deprecated by 1243 cgroup v2 implementation. The v1 is there for legacy applications 1244 which haven't migrated to the new cgroup v2 interface yet. Legacy 1245 interface includes cpuset filesystem and /proc/<pid>/cpuset. If you 1246 do not have any such application then you are completely fine leaving 1247 this option disabled. 1248 1249 Say N if unsure. 1250 1251config PROC_PID_CPUSET 1252 bool "Include legacy /proc/<pid>/cpuset file" 1253 depends on CPUSETS_V1 1254 default y 1255 1256config CGROUP_DEVICE 1257 bool "Device controller" 1258 help 1259 Provides a cgroup controller implementing whitelists for 1260 devices which a process in the cgroup can mknod or open. 1261 1262config CGROUP_CPUACCT 1263 bool "Simple CPU accounting controller" 1264 help 1265 Provides a simple controller for monitoring the 1266 total CPU consumed by the tasks in a cgroup. 1267 1268config CGROUP_PERF 1269 bool "Perf controller" 1270 depends on PERF_EVENTS 1271 help 1272 This option extends the perf per-cpu mode to restrict monitoring 1273 to threads which belong to the cgroup specified and run on the 1274 designated cpu. Or this can be used to have cgroup ID in samples 1275 so that it can monitor performance events among cgroups. 1276 1277 Say N if unsure. 1278 1279config CGROUP_BPF 1280 bool "Support for eBPF programs attached to cgroups" 1281 depends on BPF_SYSCALL 1282 select SOCK_CGROUP_DATA 1283 help 1284 Allow attaching eBPF programs to a cgroup using the bpf(2) 1285 syscall command BPF_PROG_ATTACH. 1286 1287 In which context these programs are accessed depends on the type 1288 of attachment. For instance, programs that are attached using 1289 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of 1290 inet sockets. 1291 1292config CGROUP_MISC 1293 bool "Misc resource controller" 1294 default n 1295 help 1296 Provides a controller for miscellaneous resources on a host. 1297 1298 Miscellaneous scalar resources are the resources on the host system 1299 which cannot be abstracted like the other cgroups. This controller 1300 tracks and limits the miscellaneous resources used by a process 1301 attached to a cgroup hierarchy. 1302 1303 For more information, please check misc cgroup section in 1304 /Documentation/admin-guide/cgroup-v2.rst. 1305 1306config CGROUP_DEBUG 1307 bool "Debug controller" 1308 default n 1309 depends on DEBUG_KERNEL 1310 help 1311 This option enables a simple controller that exports 1312 debugging information about the cgroups framework. This 1313 controller is for control cgroup debugging only. Its 1314 interfaces are not stable. 1315 1316 Say N. 1317 1318config SOCK_CGROUP_DATA 1319 bool 1320 default n 1321 1322endif # CGROUPS 1323 1324menuconfig NAMESPACES 1325 bool "Namespaces support" if EXPERT 1326 depends on MULTIUSER 1327 default !EXPERT 1328 help 1329 Provides the way to make tasks work with different objects using 1330 the same id. For example same IPC id may refer to different objects 1331 or same user id or pid may refer to different tasks when used in 1332 different namespaces. 1333 1334if NAMESPACES 1335 1336config UTS_NS 1337 bool "UTS namespace" 1338 default y 1339 help 1340 In this namespace tasks see different info provided with the 1341 uname() system call 1342 1343config TIME_NS 1344 bool "TIME namespace" 1345 depends on GENERIC_VDSO_TIME_NS 1346 default y 1347 help 1348 In this namespace boottime and monotonic clocks can be set. 1349 The time will keep going with the same pace. 1350 1351config IPC_NS 1352 bool "IPC namespace" 1353 depends on (SYSVIPC || POSIX_MQUEUE) 1354 default y 1355 help 1356 In this namespace tasks work with IPC ids which correspond to 1357 different IPC objects in different namespaces. 1358 1359config USER_NS 1360 bool "User namespace" 1361 default n 1362 help 1363 This allows containers, i.e. vservers, to use user namespaces 1364 to provide different user info for different servers. 1365 1366 When user namespaces are enabled in the kernel it is 1367 recommended that the MEMCG option also be enabled and that 1368 user-space use the memory control groups to limit the amount 1369 of memory a memory unprivileged users can use. 1370 1371 If unsure, say N. 1372 1373config PID_NS 1374 bool "PID Namespaces" 1375 default y 1376 help 1377 Support process id namespaces. This allows having multiple 1378 processes with the same pid as long as they are in different 1379 pid namespaces. This is a building block of containers. 1380 1381config NET_NS 1382 bool "Network namespace" 1383 depends on NET 1384 default y 1385 help 1386 Allow user space to create what appear to be multiple instances 1387 of the network stack. 1388 1389endif # NAMESPACES 1390 1391config CHECKPOINT_RESTORE 1392 bool "Checkpoint/restore support" 1393 depends on PROC_FS 1394 select PROC_CHILDREN 1395 select KCMP 1396 default n 1397 help 1398 Enables additional kernel features in a sake of checkpoint/restore. 1399 In particular it adds auxiliary prctl codes to setup process text, 1400 data and heap segment sizes, and a few additional /proc filesystem 1401 entries. 1402 1403 If unsure, say N here. 1404 1405config SCHED_AUTOGROUP 1406 bool "Automatic process group scheduling" 1407 select CGROUPS 1408 select CGROUP_SCHED 1409 select FAIR_GROUP_SCHED 1410 help 1411 This option optimizes the scheduler for common desktop workloads by 1412 automatically creating and populating task groups. This separation 1413 of workloads isolates aggressive CPU burners (like build jobs) from 1414 desktop applications. Task group autogeneration is currently based 1415 upon task session. 1416 1417config RELAY 1418 bool "Kernel->user space relay support (formerly relayfs)" 1419 select IRQ_WORK 1420 help 1421 This option enables support for relay interface support in 1422 certain file systems (such as debugfs). 1423 It is designed to provide an efficient mechanism for tools and 1424 facilities to relay large amounts of data from kernel space to 1425 user space. 1426 1427 If unsure, say N. 1428 1429config BLK_DEV_INITRD 1430 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1431 help 1432 The initial RAM filesystem is a ramfs which is loaded by the 1433 boot loader (loadlin or lilo) and that is mounted as root 1434 before the normal boot procedure. It is typically used to 1435 load modules needed to mount the "real" root file system, 1436 etc. See <file:Documentation/admin-guide/initrd.rst> for details. 1437 1438 If RAM disk support (BLK_DEV_RAM) is also included, this 1439 also enables initial RAM disk (initrd) support and adds 1440 15 Kbytes (more on some other architectures) to the kernel size. 1441 1442 If unsure say Y. 1443 1444if BLK_DEV_INITRD 1445 1446source "usr/Kconfig" 1447 1448endif 1449 1450config BOOT_CONFIG 1451 bool "Boot config support" 1452 select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED 1453 help 1454 Extra boot config allows system admin to pass a config file as 1455 complemental extension of kernel cmdline when booting. 1456 The boot config file must be attached at the end of initramfs 1457 with checksum, size and magic word. 1458 See <file:Documentation/admin-guide/bootconfig.rst> for details. 1459 1460 If unsure, say Y. 1461 1462config BOOT_CONFIG_FORCE 1463 bool "Force unconditional bootconfig processing" 1464 depends on BOOT_CONFIG 1465 default y if BOOT_CONFIG_EMBED 1466 help 1467 With this Kconfig option set, BOOT_CONFIG processing is carried 1468 out even when the "bootconfig" kernel-boot parameter is omitted. 1469 In fact, with this Kconfig option set, there is no way to 1470 make the kernel ignore the BOOT_CONFIG-supplied kernel-boot 1471 parameters. 1472 1473 If unsure, say N. 1474 1475config BOOT_CONFIG_EMBED 1476 bool "Embed bootconfig file in the kernel" 1477 depends on BOOT_CONFIG 1478 help 1479 Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the 1480 kernel. Usually, the bootconfig file is loaded with the initrd 1481 image. But if the system doesn't support initrd, this option will 1482 help you by embedding a bootconfig file while building the kernel. 1483 1484 If unsure, say N. 1485 1486config BOOT_CONFIG_EMBED_FILE 1487 string "Embedded bootconfig file path" 1488 depends on BOOT_CONFIG_EMBED 1489 help 1490 Specify a bootconfig file which will be embedded to the kernel. 1491 This bootconfig will be used if there is no initrd or no other 1492 bootconfig in the initrd. 1493 1494config INITRAMFS_PRESERVE_MTIME 1495 bool "Preserve cpio archive mtimes in initramfs" 1496 default y 1497 help 1498 Each entry in an initramfs cpio archive carries an mtime value. When 1499 enabled, extracted cpio items take this mtime, with directory mtime 1500 setting deferred until after creation of any child entries. 1501 1502 If unsure, say Y. 1503 1504config INITRAMFS_TEST 1505 bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS 1506 depends on BLK_DEV_INITRD && KUNIT=y 1507 default KUNIT_ALL_TESTS 1508 help 1509 Build KUnit tests for initramfs. See Documentation/dev-tools/kunit 1510 1511choice 1512 prompt "Compiler optimization level" 1513 default CC_OPTIMIZE_FOR_PERFORMANCE 1514 1515config CC_OPTIMIZE_FOR_PERFORMANCE 1516 bool "Optimize for performance (-O2)" 1517 help 1518 This is the default optimization level for the kernel, building 1519 with the "-O2" compiler flag for best performance and most 1520 helpful compile-time warnings. 1521 1522config CC_OPTIMIZE_FOR_SIZE 1523 bool "Optimize for size (-Os)" 1524 help 1525 Choosing this option will pass "-Os" to your compiler resulting 1526 in a smaller kernel. 1527 1528endchoice 1529 1530config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1531 bool 1532 help 1533 This requires that the arch annotates or otherwise protects 1534 its external entry points from being discarded. Linker scripts 1535 must also merge .text.*, .data.*, and .bss.* correctly into 1536 output sections. Care must be taken not to pull in unrelated 1537 sections (e.g., '.text.init'). Typically '.' in section names 1538 is used to distinguish them from label names / C identifiers. 1539 1540config LD_DEAD_CODE_DATA_ELIMINATION 1541 bool "Dead code and data elimination (EXPERIMENTAL)" 1542 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1543 depends on EXPERT 1544 depends on $(cc-option,-ffunction-sections -fdata-sections) 1545 depends on $(ld-option,--gc-sections) 1546 help 1547 Enable this if you want to do dead code and data elimination with 1548 the linker by compiling with -ffunction-sections -fdata-sections, 1549 and linking with --gc-sections. 1550 1551 This can reduce on disk and in-memory size of the kernel 1552 code and static data, particularly for small configs and 1553 on small systems. This has the possibility of introducing 1554 silently broken kernel if the required annotations are not 1555 present. This option is not well tested yet, so use at your 1556 own risk. 1557 1558config LD_ORPHAN_WARN 1559 def_bool y 1560 depends on ARCH_WANT_LD_ORPHAN_WARN 1561 depends on $(ld-option,--orphan-handling=warn) 1562 depends on $(ld-option,--orphan-handling=error) 1563 1564config LD_ORPHAN_WARN_LEVEL 1565 string 1566 depends on LD_ORPHAN_WARN 1567 default "error" if WERROR 1568 default "warn" 1569 1570config SYSCTL 1571 bool 1572 1573config HAVE_UID16 1574 bool 1575 1576config SYSCTL_EXCEPTION_TRACE 1577 bool 1578 help 1579 Enable support for /proc/sys/debug/exception-trace. 1580 1581config SYSCTL_ARCH_UNALIGN_NO_WARN 1582 bool 1583 help 1584 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1585 Allows arch to define/use @no_unaligned_warning to possibly warn 1586 about unaligned access emulation going on under the hood. 1587 1588config SYSCTL_ARCH_UNALIGN_ALLOW 1589 bool 1590 help 1591 Enable support for /proc/sys/kernel/unaligned-trap 1592 Allows arches to define/use @unaligned_enabled to runtime toggle 1593 the unaligned access emulation. 1594 see arch/parisc/kernel/unaligned.c for reference 1595 1596config SYSFS_SYSCALL 1597 bool "Sysfs syscall support" 1598 default n 1599 help 1600 sys_sysfs is an obsolete system call no longer supported in libc. 1601 Note that disabling this option is more secure but might break 1602 compatibility with some systems. 1603 1604 If unsure say N here. 1605 1606config HAVE_PCSPKR_PLATFORM 1607 bool 1608 1609menuconfig EXPERT 1610 bool "Configure standard kernel features (expert users)" 1611 # Unhide debug options, to make the on-by-default options visible 1612 select DEBUG_KERNEL 1613 help 1614 This option allows certain base kernel options and settings 1615 to be disabled or tweaked. This is for specialized 1616 environments which can tolerate a "non-standard" kernel. 1617 Only use this if you really know what you are doing. 1618 1619config UID16 1620 bool "Enable 16-bit UID system calls" if EXPERT 1621 depends on HAVE_UID16 && MULTIUSER 1622 default y 1623 help 1624 This enables the legacy 16-bit UID syscall wrappers. 1625 1626config MULTIUSER 1627 bool "Multiple users, groups and capabilities support" if EXPERT 1628 default y 1629 help 1630 This option enables support for non-root users, groups and 1631 capabilities. 1632 1633 If you say N here, all processes will run with UID 0, GID 0, and all 1634 possible capabilities. Saying N here also compiles out support for 1635 system calls related to UIDs, GIDs, and capabilities, such as setuid, 1636 setgid, and capset. 1637 1638 If unsure, say Y here. 1639 1640config SGETMASK_SYSCALL 1641 bool "sgetmask/ssetmask syscalls support" if EXPERT 1642 default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH 1643 help 1644 sys_sgetmask and sys_ssetmask are obsolete system calls 1645 no longer supported in libc but still enabled by default in some 1646 architectures. 1647 1648 If unsure, leave the default option here. 1649 1650config FHANDLE 1651 bool "open by fhandle syscalls" if EXPERT 1652 select EXPORTFS 1653 default y 1654 help 1655 If you say Y here, a user level program will be able to map 1656 file names to handle and then later use the handle for 1657 different file system operations. This is useful in implementing 1658 userspace file servers, which now track files using handles instead 1659 of names. The handle would remain the same even if file names 1660 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 1661 syscalls. 1662 1663config POSIX_TIMERS 1664 bool "Posix Clocks & timers" if EXPERT 1665 default y 1666 help 1667 This includes native support for POSIX timers to the kernel. 1668 Some embedded systems have no use for them and therefore they 1669 can be configured out to reduce the size of the kernel image. 1670 1671 When this option is disabled, the following syscalls won't be 1672 available: timer_create, timer_gettime: timer_getoverrun, 1673 timer_settime, timer_delete, clock_adjtime, getitimer, 1674 setitimer, alarm. Furthermore, the clock_settime, clock_gettime, 1675 clock_getres and clock_nanosleep syscalls will be limited to 1676 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. 1677 1678 If unsure say y. 1679 1680config PRINTK 1681 default y 1682 bool "Enable support for printk" if EXPERT 1683 select IRQ_WORK 1684 help 1685 This option enables normal printk support. Removing it 1686 eliminates most of the message strings from the kernel image 1687 and makes the kernel more or less silent. As this makes it 1688 very difficult to diagnose system problems, saying N here is 1689 strongly discouraged. 1690 1691config BUG 1692 bool "BUG() support" if EXPERT 1693 default y 1694 help 1695 Disabling this option eliminates support for BUG and WARN, reducing 1696 the size of your kernel image and potentially quietly ignoring 1697 numerous fatal conditions. You should only consider disabling this 1698 option for embedded systems with no facilities for reporting errors. 1699 Just say Y. 1700 1701config ELF_CORE 1702 depends on COREDUMP 1703 default y 1704 bool "Enable ELF core dumps" if EXPERT 1705 help 1706 Enable support for generating core dumps. Disabling saves about 4k. 1707 1708 1709config PCSPKR_PLATFORM 1710 bool "Enable PC-Speaker support" if EXPERT 1711 depends on HAVE_PCSPKR_PLATFORM 1712 select I8253_LOCK 1713 default y 1714 help 1715 This option allows to disable the internal PC-Speaker 1716 support, saving some memory. 1717 1718config BASE_SMALL 1719 bool "Enable smaller-sized data structures for core" if EXPERT 1720 help 1721 Enabling this option reduces the size of miscellaneous core 1722 kernel data structures. This saves memory on small machines, 1723 but may reduce performance. 1724 1725config FUTEX 1726 bool "Enable futex support" if EXPERT 1727 depends on !(SPARC32 && SMP) 1728 default y 1729 imply RT_MUTEXES 1730 help 1731 Disabling this option will cause the kernel to be built without 1732 support for "fast userspace mutexes". The resulting kernel may not 1733 run glibc-based applications correctly. 1734 1735config FUTEX_PI 1736 bool 1737 depends on FUTEX && RT_MUTEXES 1738 default y 1739 1740config FUTEX_PRIVATE_HASH 1741 bool 1742 depends on FUTEX && !BASE_SMALL && MMU 1743 default y 1744 1745config FUTEX_MPOL 1746 bool 1747 depends on FUTEX && NUMA 1748 default y 1749 1750config EPOLL 1751 bool "Enable eventpoll support" if EXPERT 1752 default y 1753 help 1754 Disabling this option will cause the kernel to be built without 1755 support for epoll family of system calls. 1756 1757config SIGNALFD 1758 bool "Enable signalfd() system call" if EXPERT 1759 default y 1760 help 1761 Enable the signalfd() system call that allows to receive signals 1762 on a file descriptor. 1763 1764 If unsure, say Y. 1765 1766config TIMERFD 1767 bool "Enable timerfd() system call" if EXPERT 1768 default y 1769 help 1770 Enable the timerfd() system call that allows to receive timer 1771 events on a file descriptor. 1772 1773 If unsure, say Y. 1774 1775config EVENTFD 1776 bool "Enable eventfd() system call" if EXPERT 1777 default y 1778 help 1779 Enable the eventfd() system call that allows to receive both 1780 kernel notification (ie. KAIO) or userspace notifications. 1781 1782 If unsure, say Y. 1783 1784config SHMEM 1785 bool "Use full shmem filesystem" if EXPERT 1786 default y 1787 depends on MMU 1788 help 1789 The shmem is an internal filesystem used to manage shared memory. 1790 It is backed by swap and manages resource limits. It is also exported 1791 to userspace as tmpfs if TMPFS is enabled. Disabling this 1792 option replaces shmem and tmpfs with the much simpler ramfs code, 1793 which may be appropriate on small systems without swap. 1794 1795config AIO 1796 bool "Enable AIO support" if EXPERT 1797 default y 1798 help 1799 This option enables POSIX asynchronous I/O which may by used 1800 by some high performance threaded applications. Disabling 1801 this option saves about 7k. 1802 1803config IO_URING 1804 bool "Enable IO uring support" if EXPERT 1805 select IO_WQ 1806 default y 1807 help 1808 This option enables support for the io_uring interface, enabling 1809 applications to submit and complete IO through submission and 1810 completion rings that are shared between the kernel and application. 1811 1812config GCOV_PROFILE_URING 1813 bool "Enable GCOV profiling on the io_uring subsystem" 1814 depends on IO_URING && GCOV_KERNEL 1815 help 1816 Enable GCOV profiling on the io_uring subsystem, to facilitate 1817 code coverage testing. 1818 1819 If unsure, say N. 1820 1821 Note that this will have a negative impact on the performance of 1822 the io_uring subsystem, hence this should only be enabled for 1823 specific test purposes. 1824 1825config IO_URING_MOCK_FILE 1826 tristate "Enable io_uring mock files (Experimental)" if EXPERT 1827 default n 1828 depends on IO_URING 1829 help 1830 Enable mock files for io_uring subststem testing. The ABI might 1831 still change, so it's still experimental and should only be enabled 1832 for specific test purposes. 1833 1834 If unsure, say N. 1835 1836config ADVISE_SYSCALLS 1837 bool "Enable madvise/fadvise syscalls" if EXPERT 1838 default y 1839 help 1840 This option enables the madvise and fadvise syscalls, used by 1841 applications to advise the kernel about their future memory or file 1842 usage, improving performance. If building an embedded system where no 1843 applications use these syscalls, you can disable this option to save 1844 space. 1845 1846config MEMBARRIER 1847 bool "Enable membarrier() system call" if EXPERT 1848 default y 1849 help 1850 Enable the membarrier() system call that allows issuing memory 1851 barriers across all running threads, which can be used to distribute 1852 the cost of user-space memory barriers asymmetrically by transforming 1853 pairs of memory barriers into pairs consisting of membarrier() and a 1854 compiler barrier. 1855 1856 If unsure, say Y. 1857 1858config KCMP 1859 bool "Enable kcmp() system call" if EXPERT 1860 help 1861 Enable the kernel resource comparison system call. It provides 1862 user-space with the ability to compare two processes to see if they 1863 share a common resource, such as a file descriptor or even virtual 1864 memory space. 1865 1866 If unsure, say N. 1867 1868config RSEQ 1869 bool "Enable rseq() system call" if EXPERT 1870 default y 1871 depends on HAVE_RSEQ 1872 select MEMBARRIER 1873 help 1874 Enable the restartable sequences system call. It provides a 1875 user-space cache for the current CPU number value, which 1876 speeds up getting the current CPU number from user-space, 1877 as well as an ABI to speed up user-space operations on 1878 per-CPU data. 1879 1880 If unsure, say Y. 1881 1882config DEBUG_RSEQ 1883 default n 1884 bool "Enable debugging of rseq() system call" if EXPERT 1885 depends on RSEQ && DEBUG_KERNEL 1886 help 1887 Enable extra debugging checks for the rseq system call. 1888 1889 If unsure, say N. 1890 1891config CACHESTAT_SYSCALL 1892 bool "Enable cachestat() system call" if EXPERT 1893 default y 1894 help 1895 Enable the cachestat system call, which queries the page cache 1896 statistics of a file (number of cached pages, dirty pages, 1897 pages marked for writeback, (recently) evicted pages). 1898 1899 If unsure say Y here. 1900 1901config KALLSYMS 1902 bool "Load all symbols for debugging/ksymoops" if EXPERT 1903 default y 1904 help 1905 Say Y here to let the kernel print out symbolic crash information and 1906 symbolic stack backtraces. This increases the size of the kernel 1907 somewhat, as all symbols have to be loaded into the kernel image. 1908 1909config KALLSYMS_SELFTEST 1910 bool "Test the basic functions and performance of kallsyms" 1911 depends on KALLSYMS 1912 default n 1913 help 1914 Test the basic functions and performance of some interfaces, such as 1915 kallsyms_lookup_name. It also calculates the compression rate of the 1916 kallsyms compression algorithm for the current symbol set. 1917 1918 Start self-test automatically after system startup. Suggest executing 1919 "dmesg | grep kallsyms_selftest" to collect test results. "finish" is 1920 displayed in the last line, indicating that the test is complete. 1921 1922config KALLSYMS_ALL 1923 bool "Include all symbols in kallsyms" 1924 depends on DEBUG_KERNEL && KALLSYMS 1925 help 1926 Normally kallsyms only contains the symbols of functions for nicer 1927 OOPS messages and backtraces (i.e., symbols from the text and inittext 1928 sections). This is sufficient for most cases. And only if you want to 1929 enable kernel live patching, or other less common use cases (e.g., 1930 when a debugger is used) all symbols are required (i.e., names of 1931 variables from the data sections, etc). 1932 1933 This option makes sure that all symbols are loaded into the kernel 1934 image (i.e., symbols from all sections) in cost of increased kernel 1935 size (depending on the kernel configuration, it may be 300KiB or 1936 something like this). 1937 1938 Say N unless you really need all symbols, or kernel live patching. 1939 1940# end of the "standard kernel features (expert users)" menu 1941 1942config ARCH_HAS_MEMBARRIER_CALLBACKS 1943 bool 1944 1945config ARCH_HAS_MEMBARRIER_SYNC_CORE 1946 bool 1947 1948config ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 1949 bool 1950 help 1951 Control MSEAL_SYSTEM_MAPPINGS access based on architecture. 1952 1953 A 64-bit kernel is required for the memory sealing feature. 1954 No specific hardware features from the CPU are needed. 1955 1956 To enable this feature, the architecture needs to update their 1957 special mappings calls to include the sealing flag and confirm 1958 that it doesn't unmap/remap system mappings during the life 1959 time of the process. The existence of this flag for an architecture 1960 implies that it does not require the remapping of the system 1961 mappings during process lifetime, so sealing these mappings is safe 1962 from a kernel perspective. 1963 1964 After the architecture enables this, a distribution can set 1965 CONFIG_MSEAL_SYSTEM_MAPPING to manage access to the feature. 1966 1967 For complete descriptions of memory sealing, please see 1968 Documentation/userspace-api/mseal.rst 1969 1970config HAVE_PERF_EVENTS 1971 bool 1972 help 1973 See tools/perf/design.txt for details. 1974 1975config GUEST_PERF_EVENTS 1976 bool 1977 depends on HAVE_PERF_EVENTS 1978 1979config PERF_USE_VMALLOC 1980 bool 1981 help 1982 See tools/perf/design.txt for details 1983 1984menu "Kernel Performance Events And Counters" 1985 1986config PERF_EVENTS 1987 bool "Kernel performance events and counters" 1988 default y if PROFILING 1989 depends on HAVE_PERF_EVENTS 1990 select IRQ_WORK 1991 help 1992 Enable kernel support for various performance events provided 1993 by software and hardware. 1994 1995 Software events are supported either built-in or via the 1996 use of generic tracepoints. 1997 1998 Most modern CPUs support performance events via performance 1999 counter registers. These registers count the number of certain 2000 types of hw events: such as instructions executed, cachemisses 2001 suffered, or branches mis-predicted - without slowing down the 2002 kernel or applications. These registers can also trigger interrupts 2003 when a threshold number of events have passed - and can thus be 2004 used to profile the code that runs on that CPU. 2005 2006 The Linux Performance Event subsystem provides an abstraction of 2007 these software and hardware event capabilities, available via a 2008 system call and used by the "perf" utility in tools/perf/. It 2009 provides per task and per CPU counters, and it provides event 2010 capabilities on top of those. 2011 2012 Say Y if unsure. 2013 2014config DEBUG_PERF_USE_VMALLOC 2015 default n 2016 bool "Debug: use vmalloc to back perf mmap() buffers" 2017 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC 2018 select PERF_USE_VMALLOC 2019 help 2020 Use vmalloc memory to back perf mmap() buffers. 2021 2022 Mostly useful for debugging the vmalloc code on platforms 2023 that don't require it. 2024 2025 Say N if unsure. 2026 2027endmenu 2028 2029config SYSTEM_DATA_VERIFICATION 2030 def_bool n 2031 select SYSTEM_TRUSTED_KEYRING 2032 select KEYS 2033 select CRYPTO 2034 select CRYPTO_RSA 2035 select ASYMMETRIC_KEY_TYPE 2036 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 2037 select ASN1 2038 select OID_REGISTRY 2039 select X509_CERTIFICATE_PARSER 2040 select PKCS7_MESSAGE_PARSER 2041 help 2042 Provide PKCS#7 message verification using the contents of the system 2043 trusted keyring to provide public keys. This then can be used for 2044 module verification, kexec image verification and firmware blob 2045 verification. 2046 2047config PROFILING 2048 bool "Profiling support" 2049 help 2050 Say Y here to enable the extended profiling support mechanisms used 2051 by profilers. 2052 2053config RUST 2054 bool "Rust support" 2055 depends on HAVE_RUST 2056 depends on RUST_IS_AVAILABLE 2057 select EXTENDED_MODVERSIONS if MODVERSIONS 2058 depends on !MODVERSIONS || GENDWARFKSYMS 2059 depends on !GCC_PLUGIN_RANDSTRUCT 2060 depends on !RANDSTRUCT 2061 depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO) 2062 depends on !CFI_CLANG || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC 2063 select CFI_ICALL_NORMALIZE_INTEGERS if CFI_CLANG 2064 depends on !CALL_PADDING || RUSTC_VERSION >= 108100 2065 depends on !KASAN_SW_TAGS 2066 depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300 2067 help 2068 Enables Rust support in the kernel. 2069 2070 This allows other Rust-related options, like drivers written in Rust, 2071 to be selected. 2072 2073 It is also required to be able to load external kernel modules 2074 written in Rust. 2075 2076 See Documentation/rust/ for more information. 2077 2078 If unsure, say N. 2079 2080config RUSTC_VERSION_TEXT 2081 string 2082 depends on RUST 2083 default "$(RUSTC_VERSION_TEXT)" 2084 help 2085 See `CC_VERSION_TEXT`. 2086 2087config BINDGEN_VERSION_TEXT 2088 string 2089 depends on RUST 2090 # The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0 2091 # (https://github.com/rust-lang/rust-bindgen/pull/2678) and 0.71.0 2092 # (https://github.com/rust-lang/rust-bindgen/pull/3040). It can be removed 2093 # when the minimum version is upgraded past the latter (0.69.1 and 0.71.1 2094 # both fixed the issue). 2095 default "$(shell,$(BINDGEN) --version workaround-for-0.69.0 2>/dev/null)" 2096 2097# 2098# Place an empty function call at each tracepoint site. Can be 2099# dynamically changed for a probe function. 2100# 2101config TRACEPOINTS 2102 bool 2103 select TASKS_TRACE_RCU 2104 2105source "kernel/Kconfig.kexec" 2106 2107endmenu # General setup 2108 2109source "arch/Kconfig" 2110 2111config RT_MUTEXES 2112 bool 2113 default y if PREEMPT_RT 2114 2115config MODULE_SIG_FORMAT 2116 def_bool n 2117 select SYSTEM_DATA_VERIFICATION 2118 2119source "kernel/module/Kconfig" 2120 2121config INIT_ALL_POSSIBLE 2122 bool 2123 help 2124 Back when each arch used to define their own cpu_online_mask and 2125 cpu_possible_mask, some of them chose to initialize cpu_possible_mask 2126 with all 1s, and others with all 0s. When they were centralised, 2127 it was better to provide this option than to break all the archs 2128 and have several arch maintainers pursuing me down dark alleys. 2129 2130source "block/Kconfig" 2131 2132config PREEMPT_NOTIFIERS 2133 bool 2134 2135config PADATA 2136 depends on SMP 2137 bool 2138 2139config ASN1 2140 tristate 2141 help 2142 Build a simple ASN.1 grammar compiler that produces a bytecode output 2143 that can be interpreted by the ASN.1 stream decoder and used to 2144 inform it as to what tags are to be expected in a stream and what 2145 functions to call on what tags. 2146 2147source "kernel/Kconfig.locks" 2148 2149config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 2150 bool 2151 2152config ARCH_HAS_PREPARE_SYNC_CORE_CMD 2153 bool 2154 2155config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2156 bool 2157 2158# It may be useful for an architecture to override the definitions of the 2159# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> 2160# and the COMPAT_ variants in <linux/compat.h>, in particular to use a 2161# different calling convention for syscalls. They can also override the 2162# macros for not-implemented syscalls in kernel/sys_ni.c and 2163# kernel/time/posix-stubs.c. All these overrides need to be available in 2164# <asm/syscall_wrapper.h>. 2165config ARCH_HAS_SYSCALL_WRAPPER 2166 def_bool n 2167