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 881endmenu 882 883# 884# For architectures that want to enable the support for NUMA-affine scheduler 885# balancing logic: 886# 887config ARCH_SUPPORTS_NUMA_BALANCING 888 bool 889 890# 891# For architectures that prefer to flush all TLBs after a number of pages 892# are unmapped instead of sending one IPI per page to flush. The architecture 893# must provide guarantees on what happens if a clean TLB cache entry is 894# written after the unmap. Details are in mm/rmap.c near the check for 895# should_defer_flush. The architecture should also consider if the full flush 896# and the refill costs are offset by the savings of sending fewer IPIs. 897config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 898 bool 899 900config CC_HAS_INT128 901 def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT 902 903config CC_IMPLICIT_FALLTHROUGH 904 string 905 default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) 906 default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) 907 908# Currently, disable gcc-10+ array-bounds globally. 909# It's still broken in gcc-13, so no upper bound yet. 910config GCC10_NO_ARRAY_BOUNDS 911 def_bool y 912 913config CC_NO_ARRAY_BOUNDS 914 bool 915 default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC10_NO_ARRAY_BOUNDS 916 917# Currently, disable -Wstringop-overflow for GCC globally. 918config GCC_NO_STRINGOP_OVERFLOW 919 def_bool y 920 921config CC_NO_STRINGOP_OVERFLOW 922 bool 923 default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW 924 925config CC_STRINGOP_OVERFLOW 926 bool 927 default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW 928 929# 930# For architectures that know their GCC __int128 support is sound 931# 932config ARCH_SUPPORTS_INT128 933 bool 934 935# For architectures that (ab)use NUMA to represent different memory regions 936# all cpu-local but of different latencies, such as SuperH. 937# 938config ARCH_WANT_NUMA_VARIABLE_LOCALITY 939 bool 940 941config NUMA_BALANCING 942 bool "Memory placement aware NUMA scheduler" 943 depends on ARCH_SUPPORTS_NUMA_BALANCING 944 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY 945 depends on SMP && NUMA && MIGRATION && !PREEMPT_RT 946 help 947 This option adds support for automatic NUMA aware memory/task placement. 948 The mechanism is quite primitive and is based on migrating memory when 949 it has references to the node the task is running on. 950 951 This system will be inactive on UMA systems. 952 953config NUMA_BALANCING_DEFAULT_ENABLED 954 bool "Automatically enable NUMA aware memory/task placement" 955 default y 956 depends on NUMA_BALANCING 957 help 958 If set, automatic NUMA balancing will be enabled if running on a NUMA 959 machine. 960 961config SLAB_OBJ_EXT 962 bool 963 964menuconfig CGROUPS 965 bool "Control Group support" 966 select KERNFS 967 help 968 This option adds support for grouping sets of processes together, for 969 use with process control subsystems such as Cpusets, CFS, memory 970 controls or device isolation. 971 See 972 - Documentation/scheduler/sched-design-CFS.rst (CFS) 973 - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation 974 and resource control) 975 976 Say N if unsure. 977 978if CGROUPS 979 980config PAGE_COUNTER 981 bool 982 983config CGROUP_FAVOR_DYNMODS 984 bool "Favor dynamic modification latency reduction by default" 985 help 986 This option enables the "favordynmods" mount option by default 987 which reduces the latencies of dynamic cgroup modifications such 988 as task migrations and controller on/offs at the cost of making 989 hot path operations such as forks and exits more expensive. 990 991 Say N if unsure. 992 993config MEMCG 994 bool "Memory controller" 995 select PAGE_COUNTER 996 select EVENTFD 997 select SLAB_OBJ_EXT 998 help 999 Provides control over the memory footprint of tasks in a cgroup. 1000 1001config MEMCG_NMI_UNSAFE 1002 bool 1003 depends on MEMCG 1004 depends on HAVE_NMI 1005 depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && !ARCH_HAVE_NMI_SAFE_CMPXCHG 1006 default y 1007 1008config MEMCG_NMI_SAFETY_REQUIRES_ATOMIC 1009 bool 1010 depends on MEMCG 1011 depends on HAVE_NMI 1012 depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && ARCH_HAVE_NMI_SAFE_CMPXCHG 1013 default y 1014 1015config MEMCG_V1 1016 bool "Legacy cgroup v1 memory controller" 1017 depends on MEMCG 1018 default n 1019 help 1020 Legacy cgroup v1 memory controller which has been deprecated by 1021 cgroup v2 implementation. The v1 is there for legacy applications 1022 which haven't migrated to the new cgroup v2 interface yet. If you 1023 do not have any such application then you are completely fine leaving 1024 this option disabled. 1025 1026 Please note that feature set of the legacy memory controller is likely 1027 going to shrink due to deprecation process. New deployments with v1 1028 controller are highly discouraged. 1029 1030 Say N if unsure. 1031 1032config BLK_CGROUP 1033 bool "IO controller" 1034 depends on BLOCK 1035 default n 1036 help 1037 Generic block IO controller cgroup interface. This is the common 1038 cgroup interface which should be used by various IO controlling 1039 policies. 1040 1041 Currently, CFQ IO scheduler uses it to recognize task groups and 1042 control disk bandwidth allocation (proportional time slice allocation) 1043 to such task groups. It is also used by bio throttling logic in 1044 block layer to implement upper limit in IO rates on a device. 1045 1046 This option only enables generic Block IO controller infrastructure. 1047 One needs to also enable actual IO controlling logic/policy. For 1048 enabling proportional weight division of disk bandwidth in CFQ, set 1049 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 1050 CONFIG_BLK_DEV_THROTTLING=y. 1051 1052 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information. 1053 1054config CGROUP_WRITEBACK 1055 bool 1056 depends on MEMCG && BLK_CGROUP 1057 default y 1058 1059menuconfig CGROUP_SCHED 1060 bool "CPU controller" 1061 default n 1062 help 1063 This feature lets CPU scheduler recognize task groups and control CPU 1064 bandwidth allocation to such task groups. It uses cgroups to group 1065 tasks. 1066 1067if CGROUP_SCHED 1068config GROUP_SCHED_WEIGHT 1069 def_bool n 1070 1071config FAIR_GROUP_SCHED 1072 bool "Group scheduling for SCHED_OTHER" 1073 depends on CGROUP_SCHED 1074 select GROUP_SCHED_WEIGHT 1075 default CGROUP_SCHED 1076 1077config CFS_BANDWIDTH 1078 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 1079 depends on FAIR_GROUP_SCHED 1080 default n 1081 help 1082 This option allows users to define CPU bandwidth rates (limits) for 1083 tasks running within the fair group scheduler. Groups with no limit 1084 set are considered to be unconstrained and will run with no 1085 restriction. 1086 See Documentation/scheduler/sched-bwc.rst for more information. 1087 1088config RT_GROUP_SCHED 1089 bool "Group scheduling for SCHED_RR/FIFO" 1090 depends on CGROUP_SCHED 1091 default n 1092 help 1093 This feature lets you explicitly allocate real CPU bandwidth 1094 to task groups. If enabled, it will also make it impossible to 1095 schedule realtime tasks for non-root users until you allocate 1096 realtime bandwidth for them. 1097 See Documentation/scheduler/sched-rt-group.rst for more information. 1098 1099config RT_GROUP_SCHED_DEFAULT_DISABLED 1100 bool "Require boot parameter to enable group scheduling for SCHED_RR/FIFO" 1101 depends on RT_GROUP_SCHED 1102 default n 1103 help 1104 When set, the RT group scheduling is disabled by default. The option 1105 is in inverted form so that mere RT_GROUP_SCHED enables the group 1106 scheduling. 1107 1108 Say N if unsure. 1109 1110config EXT_GROUP_SCHED 1111 bool 1112 depends on SCHED_CLASS_EXT && CGROUP_SCHED 1113 select GROUP_SCHED_WEIGHT 1114 default y 1115 1116endif #CGROUP_SCHED 1117 1118config SCHED_MM_CID 1119 def_bool y 1120 depends on SMP && RSEQ 1121 1122config UCLAMP_TASK_GROUP 1123 bool "Utilization clamping per group of tasks" 1124 depends on CGROUP_SCHED 1125 depends on UCLAMP_TASK 1126 default n 1127 help 1128 This feature enables the scheduler to track the clamped utilization 1129 of each CPU based on RUNNABLE tasks currently scheduled on that CPU. 1130 1131 When this option is enabled, the user can specify a min and max 1132 CPU bandwidth which is allowed for each single task in a group. 1133 The max bandwidth allows to clamp the maximum frequency a task 1134 can use, while the min bandwidth allows to define a minimum 1135 frequency a task will always use. 1136 1137 When task group based utilization clamping is enabled, an eventually 1138 specified task-specific clamp value is constrained by the cgroup 1139 specified clamp value. Both minimum and maximum task clamping cannot 1140 be bigger than the corresponding clamping defined at task group level. 1141 1142 If in doubt, say N. 1143 1144config CGROUP_PIDS 1145 bool "PIDs controller" 1146 help 1147 Provides enforcement of process number limits in the scope of a 1148 cgroup. Any attempt to fork more processes than is allowed in the 1149 cgroup will fail. PIDs are fundamentally a global resource because it 1150 is fairly trivial to reach PID exhaustion before you reach even a 1151 conservative kmemcg limit. As a result, it is possible to grind a 1152 system to halt without being limited by other cgroup policies. The 1153 PIDs controller is designed to stop this from happening. 1154 1155 It should be noted that organisational operations (such as attaching 1156 to a cgroup hierarchy) will *not* be blocked by the PIDs controller, 1157 since the PIDs limit only affects a process's ability to fork, not to 1158 attach to a cgroup. 1159 1160config CGROUP_RDMA 1161 bool "RDMA controller" 1162 help 1163 Provides enforcement of RDMA resources defined by IB stack. 1164 It is fairly easy for consumers to exhaust RDMA resources, which 1165 can result into resource unavailability to other consumers. 1166 RDMA controller is designed to stop this from happening. 1167 Attaching processes with active RDMA resources to the cgroup 1168 hierarchy is allowed even if can cross the hierarchy's limit. 1169 1170config CGROUP_DMEM 1171 bool "Device memory controller (DMEM)" 1172 select PAGE_COUNTER 1173 help 1174 The DMEM controller allows compatible devices to restrict device 1175 memory usage based on the cgroup hierarchy. 1176 1177 As an example, it allows you to restrict VRAM usage for applications 1178 in the DRM subsystem. 1179 1180config CGROUP_FREEZER 1181 bool "Freezer controller" 1182 help 1183 Provides a way to freeze and unfreeze all tasks in a 1184 cgroup. 1185 1186 This option affects the ORIGINAL cgroup interface. The cgroup2 memory 1187 controller includes important in-kernel memory consumers per default. 1188 1189 If you're using cgroup2, say N. 1190 1191config CGROUP_HUGETLB 1192 bool "HugeTLB controller" 1193 depends on HUGETLB_PAGE 1194 select PAGE_COUNTER 1195 default n 1196 help 1197 Provides a cgroup controller for HugeTLB pages. 1198 When you enable this, you can put a per cgroup limit on HugeTLB usage. 1199 The limit is enforced during page fault. Since HugeTLB doesn't 1200 support page reclaim, enforcing the limit at page fault time implies 1201 that, the application will get SIGBUS signal if it tries to access 1202 HugeTLB pages beyond its limit. This requires the application to know 1203 beforehand how much HugeTLB pages it would require for its use. The 1204 control group is tracked in the third page lru pointer. This means 1205 that we cannot use the controller with huge page less than 3 pages. 1206 1207config CPUSETS 1208 bool "Cpuset controller" 1209 depends on SMP 1210 select UNION_FIND 1211 help 1212 This option will let you create and manage CPUSETs which 1213 allow dynamically partitioning a system into sets of CPUs and 1214 Memory Nodes and assigning tasks to run only within those sets. 1215 This is primarily useful on large SMP or NUMA systems. 1216 1217 Say N if unsure. 1218 1219config CPUSETS_V1 1220 bool "Legacy cgroup v1 cpusets controller" 1221 depends on CPUSETS 1222 default n 1223 help 1224 Legacy cgroup v1 cpusets controller which has been deprecated by 1225 cgroup v2 implementation. The v1 is there for legacy applications 1226 which haven't migrated to the new cgroup v2 interface yet. Legacy 1227 interface includes cpuset filesystem and /proc/<pid>/cpuset. If you 1228 do not have any such application then you are completely fine leaving 1229 this option disabled. 1230 1231 Say N if unsure. 1232 1233config PROC_PID_CPUSET 1234 bool "Include legacy /proc/<pid>/cpuset file" 1235 depends on CPUSETS_V1 1236 default y 1237 1238config CGROUP_DEVICE 1239 bool "Device controller" 1240 help 1241 Provides a cgroup controller implementing whitelists for 1242 devices which a process in the cgroup can mknod or open. 1243 1244config CGROUP_CPUACCT 1245 bool "Simple CPU accounting controller" 1246 help 1247 Provides a simple controller for monitoring the 1248 total CPU consumed by the tasks in a cgroup. 1249 1250config CGROUP_PERF 1251 bool "Perf controller" 1252 depends on PERF_EVENTS 1253 help 1254 This option extends the perf per-cpu mode to restrict monitoring 1255 to threads which belong to the cgroup specified and run on the 1256 designated cpu. Or this can be used to have cgroup ID in samples 1257 so that it can monitor performance events among cgroups. 1258 1259 Say N if unsure. 1260 1261config CGROUP_BPF 1262 bool "Support for eBPF programs attached to cgroups" 1263 depends on BPF_SYSCALL 1264 select SOCK_CGROUP_DATA 1265 help 1266 Allow attaching eBPF programs to a cgroup using the bpf(2) 1267 syscall command BPF_PROG_ATTACH. 1268 1269 In which context these programs are accessed depends on the type 1270 of attachment. For instance, programs that are attached using 1271 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of 1272 inet sockets. 1273 1274config CGROUP_MISC 1275 bool "Misc resource controller" 1276 default n 1277 help 1278 Provides a controller for miscellaneous resources on a host. 1279 1280 Miscellaneous scalar resources are the resources on the host system 1281 which cannot be abstracted like the other cgroups. This controller 1282 tracks and limits the miscellaneous resources used by a process 1283 attached to a cgroup hierarchy. 1284 1285 For more information, please check misc cgroup section in 1286 /Documentation/admin-guide/cgroup-v2.rst. 1287 1288config CGROUP_DEBUG 1289 bool "Debug controller" 1290 default n 1291 depends on DEBUG_KERNEL 1292 help 1293 This option enables a simple controller that exports 1294 debugging information about the cgroups framework. This 1295 controller is for control cgroup debugging only. Its 1296 interfaces are not stable. 1297 1298 Say N. 1299 1300config SOCK_CGROUP_DATA 1301 bool 1302 default n 1303 1304endif # CGROUPS 1305 1306menuconfig NAMESPACES 1307 bool "Namespaces support" if EXPERT 1308 depends on MULTIUSER 1309 default !EXPERT 1310 help 1311 Provides the way to make tasks work with different objects using 1312 the same id. For example same IPC id may refer to different objects 1313 or same user id or pid may refer to different tasks when used in 1314 different namespaces. 1315 1316if NAMESPACES 1317 1318config UTS_NS 1319 bool "UTS namespace" 1320 default y 1321 help 1322 In this namespace tasks see different info provided with the 1323 uname() system call 1324 1325config TIME_NS 1326 bool "TIME namespace" 1327 depends on GENERIC_VDSO_TIME_NS 1328 default y 1329 help 1330 In this namespace boottime and monotonic clocks can be set. 1331 The time will keep going with the same pace. 1332 1333config IPC_NS 1334 bool "IPC namespace" 1335 depends on (SYSVIPC || POSIX_MQUEUE) 1336 default y 1337 help 1338 In this namespace tasks work with IPC ids which correspond to 1339 different IPC objects in different namespaces. 1340 1341config USER_NS 1342 bool "User namespace" 1343 default n 1344 help 1345 This allows containers, i.e. vservers, to use user namespaces 1346 to provide different user info for different servers. 1347 1348 When user namespaces are enabled in the kernel it is 1349 recommended that the MEMCG option also be enabled and that 1350 user-space use the memory control groups to limit the amount 1351 of memory a memory unprivileged users can use. 1352 1353 If unsure, say N. 1354 1355config PID_NS 1356 bool "PID Namespaces" 1357 default y 1358 help 1359 Support process id namespaces. This allows having multiple 1360 processes with the same pid as long as they are in different 1361 pid namespaces. This is a building block of containers. 1362 1363config NET_NS 1364 bool "Network namespace" 1365 depends on NET 1366 default y 1367 help 1368 Allow user space to create what appear to be multiple instances 1369 of the network stack. 1370 1371endif # NAMESPACES 1372 1373config CHECKPOINT_RESTORE 1374 bool "Checkpoint/restore support" 1375 depends on PROC_FS 1376 select PROC_CHILDREN 1377 select KCMP 1378 default n 1379 help 1380 Enables additional kernel features in a sake of checkpoint/restore. 1381 In particular it adds auxiliary prctl codes to setup process text, 1382 data and heap segment sizes, and a few additional /proc filesystem 1383 entries. 1384 1385 If unsure, say N here. 1386 1387config SCHED_AUTOGROUP 1388 bool "Automatic process group scheduling" 1389 select CGROUPS 1390 select CGROUP_SCHED 1391 select FAIR_GROUP_SCHED 1392 help 1393 This option optimizes the scheduler for common desktop workloads by 1394 automatically creating and populating task groups. This separation 1395 of workloads isolates aggressive CPU burners (like build jobs) from 1396 desktop applications. Task group autogeneration is currently based 1397 upon task session. 1398 1399config RELAY 1400 bool "Kernel->user space relay support (formerly relayfs)" 1401 select IRQ_WORK 1402 help 1403 This option enables support for relay interface support in 1404 certain file systems (such as debugfs). 1405 It is designed to provide an efficient mechanism for tools and 1406 facilities to relay large amounts of data from kernel space to 1407 user space. 1408 1409 If unsure, say N. 1410 1411config BLK_DEV_INITRD 1412 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1413 help 1414 The initial RAM filesystem is a ramfs which is loaded by the 1415 boot loader (loadlin or lilo) and that is mounted as root 1416 before the normal boot procedure. It is typically used to 1417 load modules needed to mount the "real" root file system, 1418 etc. See <file:Documentation/admin-guide/initrd.rst> for details. 1419 1420 If RAM disk support (BLK_DEV_RAM) is also included, this 1421 also enables initial RAM disk (initrd) support and adds 1422 15 Kbytes (more on some other architectures) to the kernel size. 1423 1424 If unsure say Y. 1425 1426if BLK_DEV_INITRD 1427 1428source "usr/Kconfig" 1429 1430endif 1431 1432config BOOT_CONFIG 1433 bool "Boot config support" 1434 select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED 1435 help 1436 Extra boot config allows system admin to pass a config file as 1437 complemental extension of kernel cmdline when booting. 1438 The boot config file must be attached at the end of initramfs 1439 with checksum, size and magic word. 1440 See <file:Documentation/admin-guide/bootconfig.rst> for details. 1441 1442 If unsure, say Y. 1443 1444config BOOT_CONFIG_FORCE 1445 bool "Force unconditional bootconfig processing" 1446 depends on BOOT_CONFIG 1447 default y if BOOT_CONFIG_EMBED 1448 help 1449 With this Kconfig option set, BOOT_CONFIG processing is carried 1450 out even when the "bootconfig" kernel-boot parameter is omitted. 1451 In fact, with this Kconfig option set, there is no way to 1452 make the kernel ignore the BOOT_CONFIG-supplied kernel-boot 1453 parameters. 1454 1455 If unsure, say N. 1456 1457config BOOT_CONFIG_EMBED 1458 bool "Embed bootconfig file in the kernel" 1459 depends on BOOT_CONFIG 1460 help 1461 Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the 1462 kernel. Usually, the bootconfig file is loaded with the initrd 1463 image. But if the system doesn't support initrd, this option will 1464 help you by embedding a bootconfig file while building the kernel. 1465 1466 If unsure, say N. 1467 1468config BOOT_CONFIG_EMBED_FILE 1469 string "Embedded bootconfig file path" 1470 depends on BOOT_CONFIG_EMBED 1471 help 1472 Specify a bootconfig file which will be embedded to the kernel. 1473 This bootconfig will be used if there is no initrd or no other 1474 bootconfig in the initrd. 1475 1476config INITRAMFS_PRESERVE_MTIME 1477 bool "Preserve cpio archive mtimes in initramfs" 1478 default y 1479 help 1480 Each entry in an initramfs cpio archive carries an mtime value. When 1481 enabled, extracted cpio items take this mtime, with directory mtime 1482 setting deferred until after creation of any child entries. 1483 1484 If unsure, say Y. 1485 1486config INITRAMFS_TEST 1487 bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS 1488 depends on BLK_DEV_INITRD && KUNIT=y 1489 default KUNIT_ALL_TESTS 1490 help 1491 Build KUnit tests for initramfs. See Documentation/dev-tools/kunit 1492 1493choice 1494 prompt "Compiler optimization level" 1495 default CC_OPTIMIZE_FOR_PERFORMANCE 1496 1497config CC_OPTIMIZE_FOR_PERFORMANCE 1498 bool "Optimize for performance (-O2)" 1499 help 1500 This is the default optimization level for the kernel, building 1501 with the "-O2" compiler flag for best performance and most 1502 helpful compile-time warnings. 1503 1504config CC_OPTIMIZE_FOR_SIZE 1505 bool "Optimize for size (-Os)" 1506 help 1507 Choosing this option will pass "-Os" to your compiler resulting 1508 in a smaller kernel. 1509 1510endchoice 1511 1512config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1513 bool 1514 help 1515 This requires that the arch annotates or otherwise protects 1516 its external entry points from being discarded. Linker scripts 1517 must also merge .text.*, .data.*, and .bss.* correctly into 1518 output sections. Care must be taken not to pull in unrelated 1519 sections (e.g., '.text.init'). Typically '.' in section names 1520 is used to distinguish them from label names / C identifiers. 1521 1522config LD_DEAD_CODE_DATA_ELIMINATION 1523 bool "Dead code and data elimination (EXPERIMENTAL)" 1524 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1525 depends on EXPERT 1526 depends on $(cc-option,-ffunction-sections -fdata-sections) 1527 depends on $(ld-option,--gc-sections) 1528 help 1529 Enable this if you want to do dead code and data elimination with 1530 the linker by compiling with -ffunction-sections -fdata-sections, 1531 and linking with --gc-sections. 1532 1533 This can reduce on disk and in-memory size of the kernel 1534 code and static data, particularly for small configs and 1535 on small systems. This has the possibility of introducing 1536 silently broken kernel if the required annotations are not 1537 present. This option is not well tested yet, so use at your 1538 own risk. 1539 1540config LD_ORPHAN_WARN 1541 def_bool y 1542 depends on ARCH_WANT_LD_ORPHAN_WARN 1543 depends on $(ld-option,--orphan-handling=warn) 1544 depends on $(ld-option,--orphan-handling=error) 1545 1546config LD_ORPHAN_WARN_LEVEL 1547 string 1548 depends on LD_ORPHAN_WARN 1549 default "error" if WERROR 1550 default "warn" 1551 1552config SYSCTL 1553 bool 1554 1555config HAVE_UID16 1556 bool 1557 1558config SYSCTL_EXCEPTION_TRACE 1559 bool 1560 help 1561 Enable support for /proc/sys/debug/exception-trace. 1562 1563config SYSCTL_ARCH_UNALIGN_NO_WARN 1564 bool 1565 help 1566 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1567 Allows arch to define/use @no_unaligned_warning to possibly warn 1568 about unaligned access emulation going on under the hood. 1569 1570config SYSCTL_ARCH_UNALIGN_ALLOW 1571 bool 1572 help 1573 Enable support for /proc/sys/kernel/unaligned-trap 1574 Allows arches to define/use @unaligned_enabled to runtime toggle 1575 the unaligned access emulation. 1576 see arch/parisc/kernel/unaligned.c for reference 1577 1578config SYSFS_SYSCALL 1579 bool "Sysfs syscall support" 1580 default n 1581 help 1582 sys_sysfs is an obsolete system call no longer supported in libc. 1583 Note that disabling this option is more secure but might break 1584 compatibility with some systems. 1585 1586 If unsure say N here. 1587 1588config HAVE_PCSPKR_PLATFORM 1589 bool 1590 1591menuconfig EXPERT 1592 bool "Configure standard kernel features (expert users)" 1593 # Unhide debug options, to make the on-by-default options visible 1594 select DEBUG_KERNEL 1595 help 1596 This option allows certain base kernel options and settings 1597 to be disabled or tweaked. This is for specialized 1598 environments which can tolerate a "non-standard" kernel. 1599 Only use this if you really know what you are doing. 1600 1601config UID16 1602 bool "Enable 16-bit UID system calls" if EXPERT 1603 depends on HAVE_UID16 && MULTIUSER 1604 default y 1605 help 1606 This enables the legacy 16-bit UID syscall wrappers. 1607 1608config MULTIUSER 1609 bool "Multiple users, groups and capabilities support" if EXPERT 1610 default y 1611 help 1612 This option enables support for non-root users, groups and 1613 capabilities. 1614 1615 If you say N here, all processes will run with UID 0, GID 0, and all 1616 possible capabilities. Saying N here also compiles out support for 1617 system calls related to UIDs, GIDs, and capabilities, such as setuid, 1618 setgid, and capset. 1619 1620 If unsure, say Y here. 1621 1622config SGETMASK_SYSCALL 1623 bool "sgetmask/ssetmask syscalls support" if EXPERT 1624 default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH 1625 help 1626 sys_sgetmask and sys_ssetmask are obsolete system calls 1627 no longer supported in libc but still enabled by default in some 1628 architectures. 1629 1630 If unsure, leave the default option here. 1631 1632config FHANDLE 1633 bool "open by fhandle syscalls" if EXPERT 1634 select EXPORTFS 1635 default y 1636 help 1637 If you say Y here, a user level program will be able to map 1638 file names to handle and then later use the handle for 1639 different file system operations. This is useful in implementing 1640 userspace file servers, which now track files using handles instead 1641 of names. The handle would remain the same even if file names 1642 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 1643 syscalls. 1644 1645config POSIX_TIMERS 1646 bool "Posix Clocks & timers" if EXPERT 1647 default y 1648 help 1649 This includes native support for POSIX timers to the kernel. 1650 Some embedded systems have no use for them and therefore they 1651 can be configured out to reduce the size of the kernel image. 1652 1653 When this option is disabled, the following syscalls won't be 1654 available: timer_create, timer_gettime: timer_getoverrun, 1655 timer_settime, timer_delete, clock_adjtime, getitimer, 1656 setitimer, alarm. Furthermore, the clock_settime, clock_gettime, 1657 clock_getres and clock_nanosleep syscalls will be limited to 1658 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. 1659 1660 If unsure say y. 1661 1662config PRINTK 1663 default y 1664 bool "Enable support for printk" if EXPERT 1665 select IRQ_WORK 1666 help 1667 This option enables normal printk support. Removing it 1668 eliminates most of the message strings from the kernel image 1669 and makes the kernel more or less silent. As this makes it 1670 very difficult to diagnose system problems, saying N here is 1671 strongly discouraged. 1672 1673config BUG 1674 bool "BUG() support" if EXPERT 1675 default y 1676 help 1677 Disabling this option eliminates support for BUG and WARN, reducing 1678 the size of your kernel image and potentially quietly ignoring 1679 numerous fatal conditions. You should only consider disabling this 1680 option for embedded systems with no facilities for reporting errors. 1681 Just say Y. 1682 1683config ELF_CORE 1684 depends on COREDUMP 1685 default y 1686 bool "Enable ELF core dumps" if EXPERT 1687 help 1688 Enable support for generating core dumps. Disabling saves about 4k. 1689 1690 1691config PCSPKR_PLATFORM 1692 bool "Enable PC-Speaker support" if EXPERT 1693 depends on HAVE_PCSPKR_PLATFORM 1694 select I8253_LOCK 1695 default y 1696 help 1697 This option allows to disable the internal PC-Speaker 1698 support, saving some memory. 1699 1700config BASE_SMALL 1701 bool "Enable smaller-sized data structures for core" if EXPERT 1702 help 1703 Enabling this option reduces the size of miscellaneous core 1704 kernel data structures. This saves memory on small machines, 1705 but may reduce performance. 1706 1707config FUTEX 1708 bool "Enable futex support" if EXPERT 1709 depends on !(SPARC32 && SMP) 1710 default y 1711 imply RT_MUTEXES 1712 help 1713 Disabling this option will cause the kernel to be built without 1714 support for "fast userspace mutexes". The resulting kernel may not 1715 run glibc-based applications correctly. 1716 1717config FUTEX_PI 1718 bool 1719 depends on FUTEX && RT_MUTEXES 1720 default y 1721 1722config FUTEX_PRIVATE_HASH 1723 bool 1724 depends on FUTEX && !BASE_SMALL && MMU 1725 default y 1726 1727config FUTEX_MPOL 1728 bool 1729 depends on FUTEX && NUMA 1730 default y 1731 1732config EPOLL 1733 bool "Enable eventpoll support" if EXPERT 1734 default y 1735 help 1736 Disabling this option will cause the kernel to be built without 1737 support for epoll family of system calls. 1738 1739config SIGNALFD 1740 bool "Enable signalfd() system call" if EXPERT 1741 default y 1742 help 1743 Enable the signalfd() system call that allows to receive signals 1744 on a file descriptor. 1745 1746 If unsure, say Y. 1747 1748config TIMERFD 1749 bool "Enable timerfd() system call" if EXPERT 1750 default y 1751 help 1752 Enable the timerfd() system call that allows to receive timer 1753 events on a file descriptor. 1754 1755 If unsure, say Y. 1756 1757config EVENTFD 1758 bool "Enable eventfd() system call" if EXPERT 1759 default y 1760 help 1761 Enable the eventfd() system call that allows to receive both 1762 kernel notification (ie. KAIO) or userspace notifications. 1763 1764 If unsure, say Y. 1765 1766config SHMEM 1767 bool "Use full shmem filesystem" if EXPERT 1768 default y 1769 depends on MMU 1770 help 1771 The shmem is an internal filesystem used to manage shared memory. 1772 It is backed by swap and manages resource limits. It is also exported 1773 to userspace as tmpfs if TMPFS is enabled. Disabling this 1774 option replaces shmem and tmpfs with the much simpler ramfs code, 1775 which may be appropriate on small systems without swap. 1776 1777config AIO 1778 bool "Enable AIO support" if EXPERT 1779 default y 1780 help 1781 This option enables POSIX asynchronous I/O which may by used 1782 by some high performance threaded applications. Disabling 1783 this option saves about 7k. 1784 1785config IO_URING 1786 bool "Enable IO uring support" if EXPERT 1787 select IO_WQ 1788 default y 1789 help 1790 This option enables support for the io_uring interface, enabling 1791 applications to submit and complete IO through submission and 1792 completion rings that are shared between the kernel and application. 1793 1794config GCOV_PROFILE_URING 1795 bool "Enable GCOV profiling on the io_uring subsystem" 1796 depends on GCOV_KERNEL 1797 help 1798 Enable GCOV profiling on the io_uring subsystem, to facilitate 1799 code coverage testing. 1800 1801 If unsure, say N. 1802 1803 Note that this will have a negative impact on the performance of 1804 the io_uring subsystem, hence this should only be enabled for 1805 specific test purposes. 1806 1807config ADVISE_SYSCALLS 1808 bool "Enable madvise/fadvise syscalls" if EXPERT 1809 default y 1810 help 1811 This option enables the madvise and fadvise syscalls, used by 1812 applications to advise the kernel about their future memory or file 1813 usage, improving performance. If building an embedded system where no 1814 applications use these syscalls, you can disable this option to save 1815 space. 1816 1817config MEMBARRIER 1818 bool "Enable membarrier() system call" if EXPERT 1819 default y 1820 help 1821 Enable the membarrier() system call that allows issuing memory 1822 barriers across all running threads, which can be used to distribute 1823 the cost of user-space memory barriers asymmetrically by transforming 1824 pairs of memory barriers into pairs consisting of membarrier() and a 1825 compiler barrier. 1826 1827 If unsure, say Y. 1828 1829config KCMP 1830 bool "Enable kcmp() system call" if EXPERT 1831 help 1832 Enable the kernel resource comparison system call. It provides 1833 user-space with the ability to compare two processes to see if they 1834 share a common resource, such as a file descriptor or even virtual 1835 memory space. 1836 1837 If unsure, say N. 1838 1839config RSEQ 1840 bool "Enable rseq() system call" if EXPERT 1841 default y 1842 depends on HAVE_RSEQ 1843 select MEMBARRIER 1844 help 1845 Enable the restartable sequences system call. It provides a 1846 user-space cache for the current CPU number value, which 1847 speeds up getting the current CPU number from user-space, 1848 as well as an ABI to speed up user-space operations on 1849 per-CPU data. 1850 1851 If unsure, say Y. 1852 1853config DEBUG_RSEQ 1854 default n 1855 bool "Enable debugging of rseq() system call" if EXPERT 1856 depends on RSEQ && DEBUG_KERNEL 1857 help 1858 Enable extra debugging checks for the rseq system call. 1859 1860 If unsure, say N. 1861 1862config CACHESTAT_SYSCALL 1863 bool "Enable cachestat() system call" if EXPERT 1864 default y 1865 help 1866 Enable the cachestat system call, which queries the page cache 1867 statistics of a file (number of cached pages, dirty pages, 1868 pages marked for writeback, (recently) evicted pages). 1869 1870 If unsure say Y here. 1871 1872config PC104 1873 bool "PC/104 support" if EXPERT 1874 help 1875 Expose PC/104 form factor device drivers and options available for 1876 selection and configuration. Enable this option if your target 1877 machine has a PC/104 bus. 1878 1879config KALLSYMS 1880 bool "Load all symbols for debugging/ksymoops" if EXPERT 1881 default y 1882 help 1883 Say Y here to let the kernel print out symbolic crash information and 1884 symbolic stack backtraces. This increases the size of the kernel 1885 somewhat, as all symbols have to be loaded into the kernel image. 1886 1887config KALLSYMS_SELFTEST 1888 bool "Test the basic functions and performance of kallsyms" 1889 depends on KALLSYMS 1890 default n 1891 help 1892 Test the basic functions and performance of some interfaces, such as 1893 kallsyms_lookup_name. It also calculates the compression rate of the 1894 kallsyms compression algorithm for the current symbol set. 1895 1896 Start self-test automatically after system startup. Suggest executing 1897 "dmesg | grep kallsyms_selftest" to collect test results. "finish" is 1898 displayed in the last line, indicating that the test is complete. 1899 1900config KALLSYMS_ALL 1901 bool "Include all symbols in kallsyms" 1902 depends on DEBUG_KERNEL && KALLSYMS 1903 help 1904 Normally kallsyms only contains the symbols of functions for nicer 1905 OOPS messages and backtraces (i.e., symbols from the text and inittext 1906 sections). This is sufficient for most cases. And only if you want to 1907 enable kernel live patching, or other less common use cases (e.g., 1908 when a debugger is used) all symbols are required (i.e., names of 1909 variables from the data sections, etc). 1910 1911 This option makes sure that all symbols are loaded into the kernel 1912 image (i.e., symbols from all sections) in cost of increased kernel 1913 size (depending on the kernel configuration, it may be 300KiB or 1914 something like this). 1915 1916 Say N unless you really need all symbols, or kernel live patching. 1917 1918# end of the "standard kernel features (expert users)" menu 1919 1920config ARCH_HAS_MEMBARRIER_CALLBACKS 1921 bool 1922 1923config ARCH_HAS_MEMBARRIER_SYNC_CORE 1924 bool 1925 1926config ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 1927 bool 1928 help 1929 Control MSEAL_SYSTEM_MAPPINGS access based on architecture. 1930 1931 A 64-bit kernel is required for the memory sealing feature. 1932 No specific hardware features from the CPU are needed. 1933 1934 To enable this feature, the architecture needs to update their 1935 special mappings calls to include the sealing flag and confirm 1936 that it doesn't unmap/remap system mappings during the life 1937 time of the process. The existence of this flag for an architecture 1938 implies that it does not require the remapping of the system 1939 mappings during process lifetime, so sealing these mappings is safe 1940 from a kernel perspective. 1941 1942 After the architecture enables this, a distribution can set 1943 CONFIG_MSEAL_SYSTEM_MAPPING to manage access to the feature. 1944 1945 For complete descriptions of memory sealing, please see 1946 Documentation/userspace-api/mseal.rst 1947 1948config HAVE_PERF_EVENTS 1949 bool 1950 help 1951 See tools/perf/design.txt for details. 1952 1953config GUEST_PERF_EVENTS 1954 bool 1955 depends on HAVE_PERF_EVENTS 1956 1957config PERF_USE_VMALLOC 1958 bool 1959 help 1960 See tools/perf/design.txt for details 1961 1962menu "Kernel Performance Events And Counters" 1963 1964config PERF_EVENTS 1965 bool "Kernel performance events and counters" 1966 default y if PROFILING 1967 depends on HAVE_PERF_EVENTS 1968 select IRQ_WORK 1969 help 1970 Enable kernel support for various performance events provided 1971 by software and hardware. 1972 1973 Software events are supported either built-in or via the 1974 use of generic tracepoints. 1975 1976 Most modern CPUs support performance events via performance 1977 counter registers. These registers count the number of certain 1978 types of hw events: such as instructions executed, cachemisses 1979 suffered, or branches mis-predicted - without slowing down the 1980 kernel or applications. These registers can also trigger interrupts 1981 when a threshold number of events have passed - and can thus be 1982 used to profile the code that runs on that CPU. 1983 1984 The Linux Performance Event subsystem provides an abstraction of 1985 these software and hardware event capabilities, available via a 1986 system call and used by the "perf" utility in tools/perf/. It 1987 provides per task and per CPU counters, and it provides event 1988 capabilities on top of those. 1989 1990 Say Y if unsure. 1991 1992config DEBUG_PERF_USE_VMALLOC 1993 default n 1994 bool "Debug: use vmalloc to back perf mmap() buffers" 1995 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC 1996 select PERF_USE_VMALLOC 1997 help 1998 Use vmalloc memory to back perf mmap() buffers. 1999 2000 Mostly useful for debugging the vmalloc code on platforms 2001 that don't require it. 2002 2003 Say N if unsure. 2004 2005endmenu 2006 2007config SYSTEM_DATA_VERIFICATION 2008 def_bool n 2009 select SYSTEM_TRUSTED_KEYRING 2010 select KEYS 2011 select CRYPTO 2012 select CRYPTO_RSA 2013 select ASYMMETRIC_KEY_TYPE 2014 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 2015 select ASN1 2016 select OID_REGISTRY 2017 select X509_CERTIFICATE_PARSER 2018 select PKCS7_MESSAGE_PARSER 2019 help 2020 Provide PKCS#7 message verification using the contents of the system 2021 trusted keyring to provide public keys. This then can be used for 2022 module verification, kexec image verification and firmware blob 2023 verification. 2024 2025config PROFILING 2026 bool "Profiling support" 2027 help 2028 Say Y here to enable the extended profiling support mechanisms used 2029 by profilers. 2030 2031config RUST 2032 bool "Rust support" 2033 depends on HAVE_RUST 2034 depends on RUST_IS_AVAILABLE 2035 select EXTENDED_MODVERSIONS if MODVERSIONS 2036 depends on !MODVERSIONS || GENDWARFKSYMS 2037 depends on !GCC_PLUGIN_RANDSTRUCT 2038 depends on !RANDSTRUCT 2039 depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO) 2040 depends on !CFI_CLANG || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC 2041 select CFI_ICALL_NORMALIZE_INTEGERS if CFI_CLANG 2042 depends on !CALL_PADDING || RUSTC_VERSION >= 108100 2043 depends on !KASAN_SW_TAGS 2044 depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300 2045 help 2046 Enables Rust support in the kernel. 2047 2048 This allows other Rust-related options, like drivers written in Rust, 2049 to be selected. 2050 2051 It is also required to be able to load external kernel modules 2052 written in Rust. 2053 2054 See Documentation/rust/ for more information. 2055 2056 If unsure, say N. 2057 2058config RUSTC_VERSION_TEXT 2059 string 2060 depends on RUST 2061 default "$(RUSTC_VERSION_TEXT)" 2062 help 2063 See `CC_VERSION_TEXT`. 2064 2065config BINDGEN_VERSION_TEXT 2066 string 2067 depends on RUST 2068 # The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0 2069 # (https://github.com/rust-lang/rust-bindgen/pull/2678) and 0.71.0 2070 # (https://github.com/rust-lang/rust-bindgen/pull/3040). It can be removed 2071 # when the minimum version is upgraded past the latter (0.69.1 and 0.71.1 2072 # both fixed the issue). 2073 default "$(shell,$(BINDGEN) --version workaround-for-0.69.0 2>/dev/null)" 2074 2075# 2076# Place an empty function call at each tracepoint site. Can be 2077# dynamically changed for a probe function. 2078# 2079config TRACEPOINTS 2080 bool 2081 select TASKS_TRACE_RCU 2082 2083source "kernel/Kconfig.kexec" 2084 2085endmenu # General setup 2086 2087source "arch/Kconfig" 2088 2089config RT_MUTEXES 2090 bool 2091 default y if PREEMPT_RT 2092 2093config MODULE_SIG_FORMAT 2094 def_bool n 2095 select SYSTEM_DATA_VERIFICATION 2096 2097source "kernel/module/Kconfig" 2098 2099config INIT_ALL_POSSIBLE 2100 bool 2101 help 2102 Back when each arch used to define their own cpu_online_mask and 2103 cpu_possible_mask, some of them chose to initialize cpu_possible_mask 2104 with all 1s, and others with all 0s. When they were centralised, 2105 it was better to provide this option than to break all the archs 2106 and have several arch maintainers pursuing me down dark alleys. 2107 2108source "block/Kconfig" 2109 2110config PREEMPT_NOTIFIERS 2111 bool 2112 2113config PADATA 2114 depends on SMP 2115 bool 2116 2117config ASN1 2118 tristate 2119 help 2120 Build a simple ASN.1 grammar compiler that produces a bytecode output 2121 that can be interpreted by the ASN.1 stream decoder and used to 2122 inform it as to what tags are to be expected in a stream and what 2123 functions to call on what tags. 2124 2125source "kernel/Kconfig.locks" 2126 2127config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 2128 bool 2129 2130config ARCH_HAS_PREPARE_SYNC_CORE_CMD 2131 bool 2132 2133config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2134 bool 2135 2136# It may be useful for an architecture to override the definitions of the 2137# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> 2138# and the COMPAT_ variants in <linux/compat.h>, in particular to use a 2139# different calling convention for syscalls. They can also override the 2140# macros for not-implemented syscalls in kernel/sys_ni.c and 2141# kernel/time/posix-stubs.c. All these overrides need to be available in 2142# <asm/syscall_wrapper.h>. 2143config ARCH_HAS_SYSCALL_WRAPPER 2144 def_bool n 2145