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 help 1011 Provides control over the memory footprint of tasks in a cgroup. 1012 1013config MEMCG_NMI_UNSAFE 1014 bool 1015 depends on MEMCG 1016 depends on HAVE_NMI 1017 depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && !ARCH_HAVE_NMI_SAFE_CMPXCHG 1018 default y 1019 1020config MEMCG_NMI_SAFETY_REQUIRES_ATOMIC 1021 bool 1022 depends on MEMCG 1023 depends on HAVE_NMI 1024 depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && ARCH_HAVE_NMI_SAFE_CMPXCHG 1025 default y 1026 1027config MEMCG_V1 1028 bool "Legacy cgroup v1 memory controller" 1029 depends on MEMCG 1030 default n 1031 help 1032 Legacy cgroup v1 memory controller which has been deprecated by 1033 cgroup v2 implementation. The v1 is there for legacy applications 1034 which haven't migrated to the new cgroup v2 interface yet. If you 1035 do not have any such application then you are completely fine leaving 1036 this option disabled. 1037 1038 Please note that feature set of the legacy memory controller is likely 1039 going to shrink due to deprecation process. New deployments with v1 1040 controller are highly discouraged. 1041 1042 Say N if unsure. 1043 1044config BLK_CGROUP 1045 bool "IO controller" 1046 depends on BLOCK 1047 default n 1048 help 1049 Generic block IO controller cgroup interface. This is the common 1050 cgroup interface which should be used by various IO controlling 1051 policies. 1052 1053 Currently, CFQ IO scheduler uses it to recognize task groups and 1054 control disk bandwidth allocation (proportional time slice allocation) 1055 to such task groups. It is also used by bio throttling logic in 1056 block layer to implement upper limit in IO rates on a device. 1057 1058 This option only enables generic Block IO controller infrastructure. 1059 One needs to also enable actual IO controlling logic/policy. For 1060 enabling proportional weight division of disk bandwidth in CFQ, set 1061 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 1062 CONFIG_BLK_DEV_THROTTLING=y. 1063 1064 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information. 1065 1066config CGROUP_WRITEBACK 1067 bool 1068 depends on MEMCG && BLK_CGROUP 1069 default y 1070 1071menuconfig CGROUP_SCHED 1072 bool "CPU controller" 1073 default n 1074 help 1075 This feature lets CPU scheduler recognize task groups and control CPU 1076 bandwidth allocation to such task groups. It uses cgroups to group 1077 tasks. 1078 1079if CGROUP_SCHED 1080config GROUP_SCHED_WEIGHT 1081 def_bool n 1082 1083config FAIR_GROUP_SCHED 1084 bool "Group scheduling for SCHED_OTHER" 1085 depends on CGROUP_SCHED 1086 select GROUP_SCHED_WEIGHT 1087 default CGROUP_SCHED 1088 1089config CFS_BANDWIDTH 1090 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 1091 depends on FAIR_GROUP_SCHED 1092 default n 1093 help 1094 This option allows users to define CPU bandwidth rates (limits) for 1095 tasks running within the fair group scheduler. Groups with no limit 1096 set are considered to be unconstrained and will run with no 1097 restriction. 1098 See Documentation/scheduler/sched-bwc.rst for more information. 1099 1100config RT_GROUP_SCHED 1101 bool "Group scheduling for SCHED_RR/FIFO" 1102 depends on CGROUP_SCHED 1103 default n 1104 help 1105 This feature lets you explicitly allocate real CPU bandwidth 1106 to task groups. If enabled, it will also make it impossible to 1107 schedule realtime tasks for non-root users until you allocate 1108 realtime bandwidth for them. 1109 See Documentation/scheduler/sched-rt-group.rst for more information. 1110 1111config RT_GROUP_SCHED_DEFAULT_DISABLED 1112 bool "Require boot parameter to enable group scheduling for SCHED_RR/FIFO" 1113 depends on RT_GROUP_SCHED 1114 default n 1115 help 1116 When set, the RT group scheduling is disabled by default. The option 1117 is in inverted form so that mere RT_GROUP_SCHED enables the group 1118 scheduling. 1119 1120 Say N if unsure. 1121 1122config EXT_GROUP_SCHED 1123 bool 1124 depends on SCHED_CLASS_EXT && CGROUP_SCHED 1125 select GROUP_SCHED_WEIGHT 1126 default y 1127 1128endif #CGROUP_SCHED 1129 1130config SCHED_MM_CID 1131 def_bool y 1132 depends on SMP && RSEQ 1133 1134config UCLAMP_TASK_GROUP 1135 bool "Utilization clamping per group of tasks" 1136 depends on CGROUP_SCHED 1137 depends on UCLAMP_TASK 1138 default n 1139 help 1140 This feature enables the scheduler to track the clamped utilization 1141 of each CPU based on RUNNABLE tasks currently scheduled on that CPU. 1142 1143 When this option is enabled, the user can specify a min and max 1144 CPU bandwidth which is allowed for each single task in a group. 1145 The max bandwidth allows to clamp the maximum frequency a task 1146 can use, while the min bandwidth allows to define a minimum 1147 frequency a task will always use. 1148 1149 When task group based utilization clamping is enabled, an eventually 1150 specified task-specific clamp value is constrained by the cgroup 1151 specified clamp value. Both minimum and maximum task clamping cannot 1152 be bigger than the corresponding clamping defined at task group level. 1153 1154 If in doubt, say N. 1155 1156config CGROUP_PIDS 1157 bool "PIDs controller" 1158 help 1159 Provides enforcement of process number limits in the scope of a 1160 cgroup. Any attempt to fork more processes than is allowed in the 1161 cgroup will fail. PIDs are fundamentally a global resource because it 1162 is fairly trivial to reach PID exhaustion before you reach even a 1163 conservative kmemcg limit. As a result, it is possible to grind a 1164 system to halt without being limited by other cgroup policies. The 1165 PIDs controller is designed to stop this from happening. 1166 1167 It should be noted that organisational operations (such as attaching 1168 to a cgroup hierarchy) will *not* be blocked by the PIDs controller, 1169 since the PIDs limit only affects a process's ability to fork, not to 1170 attach to a cgroup. 1171 1172config CGROUP_RDMA 1173 bool "RDMA controller" 1174 help 1175 Provides enforcement of RDMA resources defined by IB stack. 1176 It is fairly easy for consumers to exhaust RDMA resources, which 1177 can result into resource unavailability to other consumers. 1178 RDMA controller is designed to stop this from happening. 1179 Attaching processes with active RDMA resources to the cgroup 1180 hierarchy is allowed even if can cross the hierarchy's limit. 1181 1182config CGROUP_DMEM 1183 bool "Device memory controller (DMEM)" 1184 select PAGE_COUNTER 1185 help 1186 The DMEM controller allows compatible devices to restrict device 1187 memory usage based on the cgroup hierarchy. 1188 1189 As an example, it allows you to restrict VRAM usage for applications 1190 in the DRM subsystem. 1191 1192config CGROUP_FREEZER 1193 bool "Freezer controller" 1194 help 1195 Provides a way to freeze and unfreeze all tasks in a 1196 cgroup. 1197 1198 This option affects the ORIGINAL cgroup interface. The cgroup2 memory 1199 controller includes important in-kernel memory consumers per default. 1200 1201 If you're using cgroup2, say N. 1202 1203config CGROUP_HUGETLB 1204 bool "HugeTLB controller" 1205 depends on HUGETLB_PAGE 1206 select PAGE_COUNTER 1207 default n 1208 help 1209 Provides a cgroup controller for HugeTLB pages. 1210 When you enable this, you can put a per cgroup limit on HugeTLB usage. 1211 The limit is enforced during page fault. Since HugeTLB doesn't 1212 support page reclaim, enforcing the limit at page fault time implies 1213 that, the application will get SIGBUS signal if it tries to access 1214 HugeTLB pages beyond its limit. This requires the application to know 1215 beforehand how much HugeTLB pages it would require for its use. The 1216 control group is tracked in the third page lru pointer. This means 1217 that we cannot use the controller with huge page less than 3 pages. 1218 1219config CPUSETS 1220 bool "Cpuset controller" 1221 depends on SMP 1222 select UNION_FIND 1223 help 1224 This option will let you create and manage CPUSETs which 1225 allow dynamically partitioning a system into sets of CPUs and 1226 Memory Nodes and assigning tasks to run only within those sets. 1227 This is primarily useful on large SMP or NUMA systems. 1228 1229 Say N if unsure. 1230 1231config CPUSETS_V1 1232 bool "Legacy cgroup v1 cpusets controller" 1233 depends on CPUSETS 1234 default n 1235 help 1236 Legacy cgroup v1 cpusets controller which has been deprecated by 1237 cgroup v2 implementation. The v1 is there for legacy applications 1238 which haven't migrated to the new cgroup v2 interface yet. Legacy 1239 interface includes cpuset filesystem and /proc/<pid>/cpuset. If you 1240 do not have any such application then you are completely fine leaving 1241 this option disabled. 1242 1243 Say N if unsure. 1244 1245config PROC_PID_CPUSET 1246 bool "Include legacy /proc/<pid>/cpuset file" 1247 depends on CPUSETS_V1 1248 default y 1249 1250config CGROUP_DEVICE 1251 bool "Device controller" 1252 help 1253 Provides a cgroup controller implementing whitelists for 1254 devices which a process in the cgroup can mknod or open. 1255 1256config CGROUP_CPUACCT 1257 bool "Simple CPU accounting controller" 1258 help 1259 Provides a simple controller for monitoring the 1260 total CPU consumed by the tasks in a cgroup. 1261 1262config CGROUP_PERF 1263 bool "Perf controller" 1264 depends on PERF_EVENTS 1265 help 1266 This option extends the perf per-cpu mode to restrict monitoring 1267 to threads which belong to the cgroup specified and run on the 1268 designated cpu. Or this can be used to have cgroup ID in samples 1269 so that it can monitor performance events among cgroups. 1270 1271 Say N if unsure. 1272 1273config CGROUP_BPF 1274 bool "Support for eBPF programs attached to cgroups" 1275 depends on BPF_SYSCALL 1276 select SOCK_CGROUP_DATA 1277 help 1278 Allow attaching eBPF programs to a cgroup using the bpf(2) 1279 syscall command BPF_PROG_ATTACH. 1280 1281 In which context these programs are accessed depends on the type 1282 of attachment. For instance, programs that are attached using 1283 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of 1284 inet sockets. 1285 1286config CGROUP_MISC 1287 bool "Misc resource controller" 1288 default n 1289 help 1290 Provides a controller for miscellaneous resources on a host. 1291 1292 Miscellaneous scalar resources are the resources on the host system 1293 which cannot be abstracted like the other cgroups. This controller 1294 tracks and limits the miscellaneous resources used by a process 1295 attached to a cgroup hierarchy. 1296 1297 For more information, please check misc cgroup section in 1298 /Documentation/admin-guide/cgroup-v2.rst. 1299 1300config CGROUP_DEBUG 1301 bool "Debug controller" 1302 default n 1303 depends on DEBUG_KERNEL 1304 help 1305 This option enables a simple controller that exports 1306 debugging information about the cgroups framework. This 1307 controller is for control cgroup debugging only. Its 1308 interfaces are not stable. 1309 1310 Say N. 1311 1312config SOCK_CGROUP_DATA 1313 bool 1314 default n 1315 1316endif # CGROUPS 1317 1318menuconfig NAMESPACES 1319 bool "Namespaces support" if EXPERT 1320 depends on MULTIUSER 1321 default !EXPERT 1322 help 1323 Provides the way to make tasks work with different objects using 1324 the same id. For example same IPC id may refer to different objects 1325 or same user id or pid may refer to different tasks when used in 1326 different namespaces. 1327 1328if NAMESPACES 1329 1330config UTS_NS 1331 bool "UTS namespace" 1332 default y 1333 help 1334 In this namespace tasks see different info provided with the 1335 uname() system call 1336 1337config TIME_NS 1338 bool "TIME namespace" 1339 depends on GENERIC_VDSO_TIME_NS 1340 default y 1341 help 1342 In this namespace boottime and monotonic clocks can be set. 1343 The time will keep going with the same pace. 1344 1345config IPC_NS 1346 bool "IPC namespace" 1347 depends on (SYSVIPC || POSIX_MQUEUE) 1348 default y 1349 help 1350 In this namespace tasks work with IPC ids which correspond to 1351 different IPC objects in different namespaces. 1352 1353config USER_NS 1354 bool "User namespace" 1355 default n 1356 help 1357 This allows containers, i.e. vservers, to use user namespaces 1358 to provide different user info for different servers. 1359 1360 When user namespaces are enabled in the kernel it is 1361 recommended that the MEMCG option also be enabled and that 1362 user-space use the memory control groups to limit the amount 1363 of memory a memory unprivileged users can use. 1364 1365 If unsure, say N. 1366 1367config PID_NS 1368 bool "PID Namespaces" 1369 default y 1370 help 1371 Support process id namespaces. This allows having multiple 1372 processes with the same pid as long as they are in different 1373 pid namespaces. This is a building block of containers. 1374 1375config NET_NS 1376 bool "Network namespace" 1377 depends on NET 1378 default y 1379 help 1380 Allow user space to create what appear to be multiple instances 1381 of the network stack. 1382 1383endif # NAMESPACES 1384 1385config CHECKPOINT_RESTORE 1386 bool "Checkpoint/restore support" 1387 depends on PROC_FS 1388 select PROC_CHILDREN 1389 select KCMP 1390 default n 1391 help 1392 Enables additional kernel features in a sake of checkpoint/restore. 1393 In particular it adds auxiliary prctl codes to setup process text, 1394 data and heap segment sizes, and a few additional /proc filesystem 1395 entries. 1396 1397 If unsure, say N here. 1398 1399config SCHED_AUTOGROUP 1400 bool "Automatic process group scheduling" 1401 select CGROUPS 1402 select CGROUP_SCHED 1403 select FAIR_GROUP_SCHED 1404 help 1405 This option optimizes the scheduler for common desktop workloads by 1406 automatically creating and populating task groups. This separation 1407 of workloads isolates aggressive CPU burners (like build jobs) from 1408 desktop applications. Task group autogeneration is currently based 1409 upon task session. 1410 1411config RELAY 1412 bool "Kernel->user space relay support (formerly relayfs)" 1413 select IRQ_WORK 1414 help 1415 This option enables support for relay interface support in 1416 certain file systems (such as debugfs). 1417 It is designed to provide an efficient mechanism for tools and 1418 facilities to relay large amounts of data from kernel space to 1419 user space. 1420 1421 If unsure, say N. 1422 1423config BLK_DEV_INITRD 1424 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1425 help 1426 The initial RAM filesystem is a ramfs which is loaded by the 1427 boot loader (loadlin or lilo) and that is mounted as root 1428 before the normal boot procedure. It is typically used to 1429 load modules needed to mount the "real" root file system, 1430 etc. See <file:Documentation/admin-guide/initrd.rst> for details. 1431 1432 If RAM disk support (BLK_DEV_RAM) is also included, this 1433 also enables initial RAM disk (initrd) support and adds 1434 15 Kbytes (more on some other architectures) to the kernel size. 1435 1436 If unsure say Y. 1437 1438if BLK_DEV_INITRD 1439 1440source "usr/Kconfig" 1441 1442endif 1443 1444config BOOT_CONFIG 1445 bool "Boot config support" 1446 select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED 1447 help 1448 Extra boot config allows system admin to pass a config file as 1449 complemental extension of kernel cmdline when booting. 1450 The boot config file must be attached at the end of initramfs 1451 with checksum, size and magic word. 1452 See <file:Documentation/admin-guide/bootconfig.rst> for details. 1453 1454 If unsure, say Y. 1455 1456config BOOT_CONFIG_FORCE 1457 bool "Force unconditional bootconfig processing" 1458 depends on BOOT_CONFIG 1459 default y if BOOT_CONFIG_EMBED 1460 help 1461 With this Kconfig option set, BOOT_CONFIG processing is carried 1462 out even when the "bootconfig" kernel-boot parameter is omitted. 1463 In fact, with this Kconfig option set, there is no way to 1464 make the kernel ignore the BOOT_CONFIG-supplied kernel-boot 1465 parameters. 1466 1467 If unsure, say N. 1468 1469config BOOT_CONFIG_EMBED 1470 bool "Embed bootconfig file in the kernel" 1471 depends on BOOT_CONFIG 1472 help 1473 Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the 1474 kernel. Usually, the bootconfig file is loaded with the initrd 1475 image. But if the system doesn't support initrd, this option will 1476 help you by embedding a bootconfig file while building the kernel. 1477 1478 If unsure, say N. 1479 1480config BOOT_CONFIG_EMBED_FILE 1481 string "Embedded bootconfig file path" 1482 depends on BOOT_CONFIG_EMBED 1483 help 1484 Specify a bootconfig file which will be embedded to the kernel. 1485 This bootconfig will be used if there is no initrd or no other 1486 bootconfig in the initrd. 1487 1488config INITRAMFS_PRESERVE_MTIME 1489 bool "Preserve cpio archive mtimes in initramfs" 1490 default y 1491 help 1492 Each entry in an initramfs cpio archive carries an mtime value. When 1493 enabled, extracted cpio items take this mtime, with directory mtime 1494 setting deferred until after creation of any child entries. 1495 1496 If unsure, say Y. 1497 1498config INITRAMFS_TEST 1499 bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS 1500 depends on BLK_DEV_INITRD && KUNIT=y 1501 default KUNIT_ALL_TESTS 1502 help 1503 Build KUnit tests for initramfs. See Documentation/dev-tools/kunit 1504 1505choice 1506 prompt "Compiler optimization level" 1507 default CC_OPTIMIZE_FOR_PERFORMANCE 1508 1509config CC_OPTIMIZE_FOR_PERFORMANCE 1510 bool "Optimize for performance (-O2)" 1511 help 1512 This is the default optimization level for the kernel, building 1513 with the "-O2" compiler flag for best performance and most 1514 helpful compile-time warnings. 1515 1516config CC_OPTIMIZE_FOR_SIZE 1517 bool "Optimize for size (-Os)" 1518 help 1519 Choosing this option will pass "-Os" to your compiler resulting 1520 in a smaller kernel. 1521 1522endchoice 1523 1524config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1525 bool 1526 help 1527 This requires that the arch annotates or otherwise protects 1528 its external entry points from being discarded. Linker scripts 1529 must also merge .text.*, .data.*, and .bss.* correctly into 1530 output sections. Care must be taken not to pull in unrelated 1531 sections (e.g., '.text.init'). Typically '.' in section names 1532 is used to distinguish them from label names / C identifiers. 1533 1534config LD_DEAD_CODE_DATA_ELIMINATION 1535 bool "Dead code and data elimination (EXPERIMENTAL)" 1536 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1537 depends on EXPERT 1538 depends on $(cc-option,-ffunction-sections -fdata-sections) 1539 depends on $(ld-option,--gc-sections) 1540 help 1541 Enable this if you want to do dead code and data elimination with 1542 the linker by compiling with -ffunction-sections -fdata-sections, 1543 and linking with --gc-sections. 1544 1545 This can reduce on disk and in-memory size of the kernel 1546 code and static data, particularly for small configs and 1547 on small systems. This has the possibility of introducing 1548 silently broken kernel if the required annotations are not 1549 present. This option is not well tested yet, so use at your 1550 own risk. 1551 1552config LD_ORPHAN_WARN 1553 def_bool y 1554 depends on ARCH_WANT_LD_ORPHAN_WARN 1555 depends on $(ld-option,--orphan-handling=warn) 1556 depends on $(ld-option,--orphan-handling=error) 1557 1558config LD_ORPHAN_WARN_LEVEL 1559 string 1560 depends on LD_ORPHAN_WARN 1561 default "error" if WERROR 1562 default "warn" 1563 1564config SYSCTL 1565 bool 1566 1567config HAVE_UID16 1568 bool 1569 1570config SYSCTL_EXCEPTION_TRACE 1571 bool 1572 help 1573 Enable support for /proc/sys/debug/exception-trace. 1574 1575config SYSCTL_ARCH_UNALIGN_NO_WARN 1576 bool 1577 help 1578 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1579 Allows arch to define/use @no_unaligned_warning to possibly warn 1580 about unaligned access emulation going on under the hood. 1581 1582config SYSCTL_ARCH_UNALIGN_ALLOW 1583 bool 1584 help 1585 Enable support for /proc/sys/kernel/unaligned-trap 1586 Allows arches to define/use @unaligned_enabled to runtime toggle 1587 the unaligned access emulation. 1588 see arch/parisc/kernel/unaligned.c for reference 1589 1590config SYSFS_SYSCALL 1591 bool "Sysfs syscall support" 1592 default n 1593 help 1594 sys_sysfs is an obsolete system call no longer supported in libc. 1595 Note that disabling this option is more secure but might break 1596 compatibility with some systems. 1597 1598 If unsure say N here. 1599 1600config HAVE_PCSPKR_PLATFORM 1601 bool 1602 1603menuconfig EXPERT 1604 bool "Configure standard kernel features (expert users)" 1605 # Unhide debug options, to make the on-by-default options visible 1606 select DEBUG_KERNEL 1607 help 1608 This option allows certain base kernel options and settings 1609 to be disabled or tweaked. This is for specialized 1610 environments which can tolerate a "non-standard" kernel. 1611 Only use this if you really know what you are doing. 1612 1613config UID16 1614 bool "Enable 16-bit UID system calls" if EXPERT 1615 depends on HAVE_UID16 && MULTIUSER 1616 default y 1617 help 1618 This enables the legacy 16-bit UID syscall wrappers. 1619 1620config MULTIUSER 1621 bool "Multiple users, groups and capabilities support" if EXPERT 1622 default y 1623 help 1624 This option enables support for non-root users, groups and 1625 capabilities. 1626 1627 If you say N here, all processes will run with UID 0, GID 0, and all 1628 possible capabilities. Saying N here also compiles out support for 1629 system calls related to UIDs, GIDs, and capabilities, such as setuid, 1630 setgid, and capset. 1631 1632 If unsure, say Y here. 1633 1634config SGETMASK_SYSCALL 1635 bool "sgetmask/ssetmask syscalls support" if EXPERT 1636 default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH 1637 help 1638 sys_sgetmask and sys_ssetmask are obsolete system calls 1639 no longer supported in libc but still enabled by default in some 1640 architectures. 1641 1642 If unsure, leave the default option here. 1643 1644config FHANDLE 1645 bool "open by fhandle syscalls" if EXPERT 1646 select EXPORTFS 1647 default y 1648 help 1649 If you say Y here, a user level program will be able to map 1650 file names to handle and then later use the handle for 1651 different file system operations. This is useful in implementing 1652 userspace file servers, which now track files using handles instead 1653 of names. The handle would remain the same even if file names 1654 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 1655 syscalls. 1656 1657config POSIX_TIMERS 1658 bool "Posix Clocks & timers" if EXPERT 1659 default y 1660 help 1661 This includes native support for POSIX timers to the kernel. 1662 Some embedded systems have no use for them and therefore they 1663 can be configured out to reduce the size of the kernel image. 1664 1665 When this option is disabled, the following syscalls won't be 1666 available: timer_create, timer_gettime: timer_getoverrun, 1667 timer_settime, timer_delete, clock_adjtime, getitimer, 1668 setitimer, alarm. Furthermore, the clock_settime, clock_gettime, 1669 clock_getres and clock_nanosleep syscalls will be limited to 1670 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. 1671 1672 If unsure say y. 1673 1674config PRINTK 1675 default y 1676 bool "Enable support for printk" if EXPERT 1677 select IRQ_WORK 1678 help 1679 This option enables normal printk support. Removing it 1680 eliminates most of the message strings from the kernel image 1681 and makes the kernel more or less silent. As this makes it 1682 very difficult to diagnose system problems, saying N here is 1683 strongly discouraged. 1684 1685config BUG 1686 bool "BUG() support" if EXPERT 1687 default y 1688 help 1689 Disabling this option eliminates support for BUG and WARN, reducing 1690 the size of your kernel image and potentially quietly ignoring 1691 numerous fatal conditions. You should only consider disabling this 1692 option for embedded systems with no facilities for reporting errors. 1693 Just say Y. 1694 1695config ELF_CORE 1696 depends on COREDUMP 1697 default y 1698 bool "Enable ELF core dumps" if EXPERT 1699 help 1700 Enable support for generating core dumps. Disabling saves about 4k. 1701 1702 1703config PCSPKR_PLATFORM 1704 bool "Enable PC-Speaker support" if EXPERT 1705 depends on HAVE_PCSPKR_PLATFORM 1706 select I8253_LOCK 1707 default y 1708 help 1709 This option allows to disable the internal PC-Speaker 1710 support, saving some memory. 1711 1712config BASE_SMALL 1713 bool "Enable smaller-sized data structures for core" if EXPERT 1714 help 1715 Enabling this option reduces the size of miscellaneous core 1716 kernel data structures. This saves memory on small machines, 1717 but may reduce performance. 1718 1719config FUTEX 1720 bool "Enable futex support" if EXPERT 1721 depends on !(SPARC32 && SMP) 1722 default y 1723 imply RT_MUTEXES 1724 help 1725 Disabling this option will cause the kernel to be built without 1726 support for "fast userspace mutexes". The resulting kernel may not 1727 run glibc-based applications correctly. 1728 1729config FUTEX_PI 1730 bool 1731 depends on FUTEX && RT_MUTEXES 1732 default y 1733 1734config FUTEX_PRIVATE_HASH 1735 bool 1736 depends on FUTEX && !BASE_SMALL && MMU 1737 default y 1738 1739config FUTEX_MPOL 1740 bool 1741 depends on FUTEX && NUMA 1742 default y 1743 1744config EPOLL 1745 bool "Enable eventpoll support" if EXPERT 1746 default y 1747 help 1748 Disabling this option will cause the kernel to be built without 1749 support for epoll family of system calls. 1750 1751config SIGNALFD 1752 bool "Enable signalfd() system call" if EXPERT 1753 default y 1754 help 1755 Enable the signalfd() system call that allows to receive signals 1756 on a file descriptor. 1757 1758 If unsure, say Y. 1759 1760config TIMERFD 1761 bool "Enable timerfd() system call" if EXPERT 1762 default y 1763 help 1764 Enable the timerfd() system call that allows to receive timer 1765 events on a file descriptor. 1766 1767 If unsure, say Y. 1768 1769config EVENTFD 1770 bool "Enable eventfd() system call" if EXPERT 1771 default y 1772 help 1773 Enable the eventfd() system call that allows to receive both 1774 kernel notification (ie. KAIO) or userspace notifications. 1775 1776 If unsure, say Y. 1777 1778config SHMEM 1779 bool "Use full shmem filesystem" if EXPERT 1780 default y 1781 depends on MMU 1782 help 1783 The shmem is an internal filesystem used to manage shared memory. 1784 It is backed by swap and manages resource limits. It is also exported 1785 to userspace as tmpfs if TMPFS is enabled. Disabling this 1786 option replaces shmem and tmpfs with the much simpler ramfs code, 1787 which may be appropriate on small systems without swap. 1788 1789config AIO 1790 bool "Enable AIO support" if EXPERT 1791 default y 1792 help 1793 This option enables POSIX asynchronous I/O which may by used 1794 by some high performance threaded applications. Disabling 1795 this option saves about 7k. 1796 1797config IO_URING 1798 bool "Enable IO uring support" if EXPERT 1799 select IO_WQ 1800 default y 1801 help 1802 This option enables support for the io_uring interface, enabling 1803 applications to submit and complete IO through submission and 1804 completion rings that are shared between the kernel and application. 1805 1806config GCOV_PROFILE_URING 1807 bool "Enable GCOV profiling on the io_uring subsystem" 1808 depends on IO_URING && GCOV_KERNEL 1809 help 1810 Enable GCOV profiling on the io_uring subsystem, to facilitate 1811 code coverage testing. 1812 1813 If unsure, say N. 1814 1815 Note that this will have a negative impact on the performance of 1816 the io_uring subsystem, hence this should only be enabled for 1817 specific test purposes. 1818 1819config IO_URING_MOCK_FILE 1820 tristate "Enable io_uring mock files (Experimental)" if EXPERT 1821 default n 1822 depends on IO_URING 1823 help 1824 Enable mock files for io_uring subststem testing. The ABI might 1825 still change, so it's still experimental and should only be enabled 1826 for specific test purposes. 1827 1828 If unsure, say N. 1829 1830config ADVISE_SYSCALLS 1831 bool "Enable madvise/fadvise syscalls" if EXPERT 1832 default y 1833 help 1834 This option enables the madvise and fadvise syscalls, used by 1835 applications to advise the kernel about their future memory or file 1836 usage, improving performance. If building an embedded system where no 1837 applications use these syscalls, you can disable this option to save 1838 space. 1839 1840config MEMBARRIER 1841 bool "Enable membarrier() system call" if EXPERT 1842 default y 1843 help 1844 Enable the membarrier() system call that allows issuing memory 1845 barriers across all running threads, which can be used to distribute 1846 the cost of user-space memory barriers asymmetrically by transforming 1847 pairs of memory barriers into pairs consisting of membarrier() and a 1848 compiler barrier. 1849 1850 If unsure, say Y. 1851 1852config KCMP 1853 bool "Enable kcmp() system call" if EXPERT 1854 help 1855 Enable the kernel resource comparison system call. It provides 1856 user-space with the ability to compare two processes to see if they 1857 share a common resource, such as a file descriptor or even virtual 1858 memory space. 1859 1860 If unsure, say N. 1861 1862config RSEQ 1863 bool "Enable rseq() system call" if EXPERT 1864 default y 1865 depends on HAVE_RSEQ 1866 select MEMBARRIER 1867 help 1868 Enable the restartable sequences system call. It provides a 1869 user-space cache for the current CPU number value, which 1870 speeds up getting the current CPU number from user-space, 1871 as well as an ABI to speed up user-space operations on 1872 per-CPU data. 1873 1874 If unsure, say Y. 1875 1876config DEBUG_RSEQ 1877 default n 1878 bool "Enable debugging of rseq() system call" if EXPERT 1879 depends on RSEQ && DEBUG_KERNEL 1880 help 1881 Enable extra debugging checks for the rseq system call. 1882 1883 If unsure, say N. 1884 1885config CACHESTAT_SYSCALL 1886 bool "Enable cachestat() system call" if EXPERT 1887 default y 1888 help 1889 Enable the cachestat system call, which queries the page cache 1890 statistics of a file (number of cached pages, dirty pages, 1891 pages marked for writeback, (recently) evicted pages). 1892 1893 If unsure say Y here. 1894 1895config KALLSYMS 1896 bool "Load all symbols for debugging/ksymoops" if EXPERT 1897 default y 1898 help 1899 Say Y here to let the kernel print out symbolic crash information and 1900 symbolic stack backtraces. This increases the size of the kernel 1901 somewhat, as all symbols have to be loaded into the kernel image. 1902 1903config KALLSYMS_SELFTEST 1904 bool "Test the basic functions and performance of kallsyms" 1905 depends on KALLSYMS 1906 default n 1907 help 1908 Test the basic functions and performance of some interfaces, such as 1909 kallsyms_lookup_name. It also calculates the compression rate of the 1910 kallsyms compression algorithm for the current symbol set. 1911 1912 Start self-test automatically after system startup. Suggest executing 1913 "dmesg | grep kallsyms_selftest" to collect test results. "finish" is 1914 displayed in the last line, indicating that the test is complete. 1915 1916config KALLSYMS_ALL 1917 bool "Include all symbols in kallsyms" 1918 depends on DEBUG_KERNEL && KALLSYMS 1919 help 1920 Normally kallsyms only contains the symbols of functions for nicer 1921 OOPS messages and backtraces (i.e., symbols from the text and inittext 1922 sections). This is sufficient for most cases. And only if you want to 1923 enable kernel live patching, or other less common use cases (e.g., 1924 when a debugger is used) all symbols are required (i.e., names of 1925 variables from the data sections, etc). 1926 1927 This option makes sure that all symbols are loaded into the kernel 1928 image (i.e., symbols from all sections) in cost of increased kernel 1929 size (depending on the kernel configuration, it may be 300KiB or 1930 something like this). 1931 1932 Say N unless you really need all symbols, or kernel live patching. 1933 1934# end of the "standard kernel features (expert users)" menu 1935 1936config ARCH_HAS_MEMBARRIER_CALLBACKS 1937 bool 1938 1939config ARCH_HAS_MEMBARRIER_SYNC_CORE 1940 bool 1941 1942config ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 1943 bool 1944 help 1945 Control MSEAL_SYSTEM_MAPPINGS access based on architecture. 1946 1947 A 64-bit kernel is required for the memory sealing feature. 1948 No specific hardware features from the CPU are needed. 1949 1950 To enable this feature, the architecture needs to update their 1951 special mappings calls to include the sealing flag and confirm 1952 that it doesn't unmap/remap system mappings during the life 1953 time of the process. The existence of this flag for an architecture 1954 implies that it does not require the remapping of the system 1955 mappings during process lifetime, so sealing these mappings is safe 1956 from a kernel perspective. 1957 1958 After the architecture enables this, a distribution can set 1959 CONFIG_MSEAL_SYSTEM_MAPPING to manage access to the feature. 1960 1961 For complete descriptions of memory sealing, please see 1962 Documentation/userspace-api/mseal.rst 1963 1964config HAVE_PERF_EVENTS 1965 bool 1966 help 1967 See tools/perf/design.txt for details. 1968 1969config GUEST_PERF_EVENTS 1970 bool 1971 depends on HAVE_PERF_EVENTS 1972 1973config PERF_USE_VMALLOC 1974 bool 1975 help 1976 See tools/perf/design.txt for details 1977 1978menu "Kernel Performance Events And Counters" 1979 1980config PERF_EVENTS 1981 bool "Kernel performance events and counters" 1982 default y if PROFILING 1983 depends on HAVE_PERF_EVENTS 1984 select IRQ_WORK 1985 help 1986 Enable kernel support for various performance events provided 1987 by software and hardware. 1988 1989 Software events are supported either built-in or via the 1990 use of generic tracepoints. 1991 1992 Most modern CPUs support performance events via performance 1993 counter registers. These registers count the number of certain 1994 types of hw events: such as instructions executed, cachemisses 1995 suffered, or branches mis-predicted - without slowing down the 1996 kernel or applications. These registers can also trigger interrupts 1997 when a threshold number of events have passed - and can thus be 1998 used to profile the code that runs on that CPU. 1999 2000 The Linux Performance Event subsystem provides an abstraction of 2001 these software and hardware event capabilities, available via a 2002 system call and used by the "perf" utility in tools/perf/. It 2003 provides per task and per CPU counters, and it provides event 2004 capabilities on top of those. 2005 2006 Say Y if unsure. 2007 2008config DEBUG_PERF_USE_VMALLOC 2009 default n 2010 bool "Debug: use vmalloc to back perf mmap() buffers" 2011 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC 2012 select PERF_USE_VMALLOC 2013 help 2014 Use vmalloc memory to back perf mmap() buffers. 2015 2016 Mostly useful for debugging the vmalloc code on platforms 2017 that don't require it. 2018 2019 Say N if unsure. 2020 2021endmenu 2022 2023config SYSTEM_DATA_VERIFICATION 2024 def_bool n 2025 select SYSTEM_TRUSTED_KEYRING 2026 select KEYS 2027 select CRYPTO 2028 select CRYPTO_RSA 2029 select ASYMMETRIC_KEY_TYPE 2030 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 2031 select ASN1 2032 select OID_REGISTRY 2033 select X509_CERTIFICATE_PARSER 2034 select PKCS7_MESSAGE_PARSER 2035 help 2036 Provide PKCS#7 message verification using the contents of the system 2037 trusted keyring to provide public keys. This then can be used for 2038 module verification, kexec image verification and firmware blob 2039 verification. 2040 2041config PROFILING 2042 bool "Profiling support" 2043 help 2044 Say Y here to enable the extended profiling support mechanisms used 2045 by profilers. 2046 2047config RUST 2048 bool "Rust support" 2049 depends on HAVE_RUST 2050 depends on RUST_IS_AVAILABLE 2051 select EXTENDED_MODVERSIONS if MODVERSIONS 2052 depends on !MODVERSIONS || GENDWARFKSYMS 2053 depends on !GCC_PLUGIN_RANDSTRUCT 2054 depends on !RANDSTRUCT 2055 depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO) 2056 depends on !CFI_CLANG || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC 2057 select CFI_ICALL_NORMALIZE_INTEGERS if CFI_CLANG 2058 depends on !CALL_PADDING || RUSTC_VERSION >= 108100 2059 depends on !KASAN_SW_TAGS 2060 depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300 2061 help 2062 Enables Rust support in the kernel. 2063 2064 This allows other Rust-related options, like drivers written in Rust, 2065 to be selected. 2066 2067 It is also required to be able to load external kernel modules 2068 written in Rust. 2069 2070 See Documentation/rust/ for more information. 2071 2072 If unsure, say N. 2073 2074config RUSTC_VERSION_TEXT 2075 string 2076 depends on RUST 2077 default "$(RUSTC_VERSION_TEXT)" 2078 help 2079 See `CC_VERSION_TEXT`. 2080 2081config BINDGEN_VERSION_TEXT 2082 string 2083 depends on RUST 2084 # The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0 2085 # (https://github.com/rust-lang/rust-bindgen/pull/2678) and 0.71.0 2086 # (https://github.com/rust-lang/rust-bindgen/pull/3040). It can be removed 2087 # when the minimum version is upgraded past the latter (0.69.1 and 0.71.1 2088 # both fixed the issue). 2089 default "$(shell,$(BINDGEN) --version workaround-for-0.69.0 2>/dev/null)" 2090 2091# 2092# Place an empty function call at each tracepoint site. Can be 2093# dynamically changed for a probe function. 2094# 2095config TRACEPOINTS 2096 bool 2097 select TASKS_TRACE_RCU 2098 2099source "kernel/Kconfig.kexec" 2100 2101endmenu # General setup 2102 2103source "arch/Kconfig" 2104 2105config RT_MUTEXES 2106 bool 2107 default y if PREEMPT_RT 2108 2109config MODULE_SIG_FORMAT 2110 def_bool n 2111 select SYSTEM_DATA_VERIFICATION 2112 2113source "kernel/module/Kconfig" 2114 2115config INIT_ALL_POSSIBLE 2116 bool 2117 help 2118 Back when each arch used to define their own cpu_online_mask and 2119 cpu_possible_mask, some of them chose to initialize cpu_possible_mask 2120 with all 1s, and others with all 0s. When they were centralised, 2121 it was better to provide this option than to break all the archs 2122 and have several arch maintainers pursuing me down dark alleys. 2123 2124source "block/Kconfig" 2125 2126config PREEMPT_NOTIFIERS 2127 bool 2128 2129config PADATA 2130 depends on SMP 2131 bool 2132 2133config ASN1 2134 tristate 2135 help 2136 Build a simple ASN.1 grammar compiler that produces a bytecode output 2137 that can be interpreted by the ASN.1 stream decoder and used to 2138 inform it as to what tags are to be expected in a stream and what 2139 functions to call on what tags. 2140 2141source "kernel/Kconfig.locks" 2142 2143config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 2144 bool 2145 2146config ARCH_HAS_PREPARE_SYNC_CORE_CMD 2147 bool 2148 2149config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2150 bool 2151 2152# It may be useful for an architecture to override the definitions of the 2153# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> 2154# and the COMPAT_ variants in <linux/compat.h>, in particular to use a 2155# different calling convention for syscalls. They can also override the 2156# macros for not-implemented syscalls in kernel/sys_ni.c and 2157# kernel/time/posix-stubs.c. All these overrides need to be available in 2158# <asm/syscall_wrapper.h>. 2159config ARCH_HAS_SYSCALL_WRAPPER 2160 def_bool n 2161