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 # TODO: when gcc 15 is released remove the build test and add 120 # a gcc version check 121 def_bool $(success,echo 'struct flex { int count; int array[] __attribute__((__counted_by__(count))); };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror) 122 # clang needs to be at least 19.1.3 to avoid __bdos miscalculations 123 # https://github.com/llvm/llvm-project/pull/110497 124 # https://github.com/llvm/llvm-project/pull/112636 125 depends on !(CC_IS_CLANG && CLANG_VERSION < 190103) 126 127config CC_HAS_MULTIDIMENSIONAL_NONSTRING 128 def_bool $(success,echo 'char tag[][4] __attribute__((__nonstring__)) = { };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror) 129 130config LD_CAN_USE_KEEP_IN_OVERLAY 131 # ld.lld prior to 21.0.0 did not support KEEP within an overlay description 132 # https://github.com/llvm/llvm-project/pull/130661 133 def_bool LD_IS_BFD || LLD_VERSION >= 210000 134 135config RUSTC_HAS_COERCE_POINTEE 136 def_bool RUSTC_VERSION >= 108400 137 138config RUSTC_HAS_UNNECESSARY_TRANSMUTES 139 def_bool RUSTC_VERSION >= 108800 140 141config PAHOLE_VERSION 142 int 143 default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE)) 144 145config CONSTRUCTORS 146 bool 147 148config IRQ_WORK 149 def_bool y if SMP 150 151config BUILDTIME_TABLE_SORT 152 bool 153 154config THREAD_INFO_IN_TASK 155 bool 156 help 157 Select this to move thread_info off the stack into task_struct. To 158 make this work, an arch will need to remove all thread_info fields 159 except flags and fix any runtime bugs. 160 161 One subtle change that will be needed is to use try_get_task_stack() 162 and put_task_stack() in save_thread_stack_tsk() and get_wchan(). 163 164menu "General setup" 165 166config BROKEN 167 bool 168 169config BROKEN_ON_SMP 170 bool 171 depends on BROKEN || !SMP 172 default y 173 174config INIT_ENV_ARG_LIMIT 175 int 176 default 32 if !UML 177 default 128 if UML 178 help 179 Maximum of each of the number of arguments and environment 180 variables passed to init from the kernel command line. 181 182config COMPILE_TEST 183 bool "Compile also drivers which will not load" 184 depends on HAS_IOMEM 185 help 186 Some drivers can be compiled on a different platform than they are 187 intended to be run on. Despite they cannot be loaded there (or even 188 when they load they cannot be used due to missing HW support), 189 developers still, opposing to distributors, might want to build such 190 drivers to compile-test them. 191 192 If you are a developer and want to build everything available, say Y 193 here. If you are a user/distributor, say N here to exclude useless 194 drivers to be distributed. 195 196config WERROR 197 bool "Compile the kernel with warnings as errors" 198 default COMPILE_TEST 199 help 200 A kernel build should not cause any compiler warnings, and this 201 enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags 202 to enforce that rule by default. Certain warnings from other tools 203 such as the linker may be upgraded to errors with this option as 204 well. 205 206 However, if you have a new (or very old) compiler or linker with odd 207 and unusual warnings, or you have some architecture with problems, 208 you may need to disable this config option in order to 209 successfully build the kernel. 210 211 If in doubt, say Y. 212 213config UAPI_HEADER_TEST 214 bool "Compile test UAPI headers" 215 depends on HEADERS_INSTALL && CC_CAN_LINK 216 help 217 Compile test headers exported to user-space to ensure they are 218 self-contained, i.e. compilable as standalone units. 219 220 If you are a developer or tester and want to ensure the exported 221 headers are self-contained, say Y here. Otherwise, choose N. 222 223config LOCALVERSION 224 string "Local version - append to kernel release" 225 help 226 Append an extra string to the end of your kernel version. 227 This will show up when you type uname, for example. 228 The string you set here will be appended after the contents of 229 any files with a filename matching localversion* in your 230 object and source tree, in that order. Your total string can 231 be a maximum of 64 characters. 232 233config LOCALVERSION_AUTO 234 bool "Automatically append version information to the version string" 235 default y 236 depends on !COMPILE_TEST 237 help 238 This will try to automatically determine if the current tree is a 239 release tree by looking for git tags that belong to the current 240 top of tree revision. 241 242 A string of the format -gxxxxxxxx will be added to the localversion 243 if a git-based tree is found. The string generated by this will be 244 appended after any matching localversion* files, and after the value 245 set in CONFIG_LOCALVERSION. 246 247 (The actual string used here is the first 12 characters produced 248 by running the command: 249 250 $ git rev-parse --verify HEAD 251 252 which is done within the script "scripts/setlocalversion".) 253 254config BUILD_SALT 255 string "Build ID Salt" 256 default "" 257 help 258 The build ID is used to link binaries and their debug info. Setting 259 this option will use the value in the calculation of the build id. 260 This is mostly useful for distributions which want to ensure the 261 build is unique between builds. It's safe to leave the default. 262 263config HAVE_KERNEL_GZIP 264 bool 265 266config HAVE_KERNEL_BZIP2 267 bool 268 269config HAVE_KERNEL_LZMA 270 bool 271 272config HAVE_KERNEL_XZ 273 bool 274 275config HAVE_KERNEL_LZO 276 bool 277 278config HAVE_KERNEL_LZ4 279 bool 280 281config HAVE_KERNEL_ZSTD 282 bool 283 284config HAVE_KERNEL_UNCOMPRESSED 285 bool 286 287choice 288 prompt "Kernel compression mode" 289 default KERNEL_GZIP 290 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 291 help 292 The linux kernel is a kind of self-extracting executable. 293 Several compression algorithms are available, which differ 294 in efficiency, compression and decompression speed. 295 Compression speed is only relevant when building a kernel. 296 Decompression speed is relevant at each boot. 297 298 If you have any problems with bzip2 or lzma compressed 299 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 300 version of this functionality (bzip2 only), for 2.4, was 301 supplied by Christian Ludwig) 302 303 High compression options are mostly useful for users, who 304 are low on disk space (embedded systems), but for whom ram 305 size matters less. 306 307 If in doubt, select 'gzip' 308 309config KERNEL_GZIP 310 bool "Gzip" 311 depends on HAVE_KERNEL_GZIP 312 help 313 The old and tried gzip compression. It provides a good balance 314 between compression ratio and decompression speed. 315 316config KERNEL_BZIP2 317 bool "Bzip2" 318 depends on HAVE_KERNEL_BZIP2 319 help 320 Its compression ratio and speed is intermediate. 321 Decompression speed is slowest among the choices. The kernel 322 size is about 10% smaller with bzip2, in comparison to gzip. 323 Bzip2 uses a large amount of memory. For modern kernels you 324 will need at least 8MB RAM or more for booting. 325 326config KERNEL_LZMA 327 bool "LZMA" 328 depends on HAVE_KERNEL_LZMA 329 help 330 This compression algorithm's ratio is best. Decompression speed 331 is between gzip and bzip2. Compression is slowest. 332 The kernel size is about 33% smaller with LZMA in comparison to gzip. 333 334config KERNEL_XZ 335 bool "XZ" 336 depends on HAVE_KERNEL_XZ 337 help 338 XZ uses the LZMA2 algorithm and instruction set specific 339 BCJ filters which can improve compression ratio of executable 340 code. The size of the kernel is about 30% smaller with XZ in 341 comparison to gzip. On architectures for which there is a BCJ 342 filter (i386, x86_64, ARM, ARM64, RISC-V, big endian PowerPC, 343 and SPARC), XZ will create a few percent smaller kernel than 344 plain LZMA. 345 346 The speed is about the same as with LZMA: The decompression 347 speed of XZ is better than that of bzip2 but worse than gzip 348 and LZO. Compression is slow. 349 350config KERNEL_LZO 351 bool "LZO" 352 depends on HAVE_KERNEL_LZO 353 help 354 Its compression ratio is the poorest among the choices. The kernel 355 size is about 10% bigger than gzip; however its speed 356 (both compression and decompression) is the fastest. 357 358config KERNEL_LZ4 359 bool "LZ4" 360 depends on HAVE_KERNEL_LZ4 361 help 362 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. 363 A preliminary version of LZ4 de/compression tool is available at 364 <https://code.google.com/p/lz4/>. 365 366 Its compression ratio is worse than LZO. The size of the kernel 367 is about 8% bigger than LZO. But the decompression speed is 368 faster than LZO. 369 370config KERNEL_ZSTD 371 bool "ZSTD" 372 depends on HAVE_KERNEL_ZSTD 373 help 374 ZSTD is a compression algorithm targeting intermediate compression 375 with fast decompression speed. It will compress better than GZIP and 376 decompress around the same speed as LZO, but slower than LZ4. You 377 will need at least 192 KB RAM or more for booting. The zstd command 378 line tool is required for compression. 379 380config KERNEL_UNCOMPRESSED 381 bool "None" 382 depends on HAVE_KERNEL_UNCOMPRESSED 383 help 384 Produce uncompressed kernel image. This option is usually not what 385 you want. It is useful for debugging the kernel in slow simulation 386 environments, where decompressing and moving the kernel is awfully 387 slow. This option allows early boot code to skip the decompressor 388 and jump right at uncompressed kernel image. 389 390endchoice 391 392config DEFAULT_INIT 393 string "Default init path" 394 default "" 395 help 396 This option determines the default init for the system if no init= 397 option is passed on the kernel command line. If the requested path is 398 not present, we will still then move on to attempting further 399 locations (e.g. /sbin/init, etc). If this is empty, we will just use 400 the fallback list when init= is not passed. 401 402config DEFAULT_HOSTNAME 403 string "Default hostname" 404 default "(none)" 405 help 406 This option determines the default system hostname before userspace 407 calls sethostname(2). The kernel traditionally uses "(none)" here, 408 but you may wish to use a different default here to make a minimal 409 system more usable with less configuration. 410 411config SYSVIPC 412 bool "System V IPC" 413 help 414 Inter Process Communication is a suite of library functions and 415 system calls which let processes (running programs) synchronize and 416 exchange information. It is generally considered to be a good thing, 417 and some programs won't run unless you say Y here. In particular, if 418 you want to run the DOS emulator dosemu under Linux (read the 419 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 420 you'll need to say Y here. 421 422 You can find documentation about IPC with "info ipc" and also in 423 section 6.4 of the Linux Programmer's Guide, available from 424 <http://www.tldp.org/guides.html>. 425 426config SYSVIPC_SYSCTL 427 bool 428 depends on SYSVIPC 429 depends on SYSCTL 430 default y 431 432config SYSVIPC_COMPAT 433 def_bool y 434 depends on COMPAT && SYSVIPC 435 436config POSIX_MQUEUE 437 bool "POSIX Message Queues" 438 depends on NET 439 help 440 POSIX variant of message queues is a part of IPC. In POSIX message 441 queues every message has a priority which decides about succession 442 of receiving it by a process. If you want to compile and run 443 programs written e.g. for Solaris with use of its POSIX message 444 queues (functions mq_*) say Y here. 445 446 POSIX message queues are visible as a filesystem called 'mqueue' 447 and can be mounted somewhere if you want to do filesystem 448 operations on message queues. 449 450 If unsure, say Y. 451 452config POSIX_MQUEUE_SYSCTL 453 bool 454 depends on POSIX_MQUEUE 455 depends on SYSCTL 456 default y 457 458config WATCH_QUEUE 459 bool "General notification queue" 460 default n 461 help 462 463 This is a general notification queue for the kernel to pass events to 464 userspace by splicing them into pipes. It can be used in conjunction 465 with watches for key/keyring change notifications and device 466 notifications. 467 468 See Documentation/core-api/watch_queue.rst 469 470config CROSS_MEMORY_ATTACH 471 bool "Enable process_vm_readv/writev syscalls" 472 depends on MMU 473 default y 474 help 475 Enabling this option adds the system calls process_vm_readv and 476 process_vm_writev which allow a process with the correct privileges 477 to directly read from or write to another process' address space. 478 See the man page for more details. 479 480config AUDIT 481 bool "Auditing support" 482 depends on NET 483 help 484 Enable auditing infrastructure that can be used with another 485 kernel subsystem, such as SELinux (which requires this for 486 logging of avc messages output). System call auditing is included 487 on architectures which support it. 488 489config HAVE_ARCH_AUDITSYSCALL 490 bool 491 492config AUDITSYSCALL 493 def_bool y 494 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL 495 select FSNOTIFY 496 497source "kernel/irq/Kconfig" 498source "kernel/time/Kconfig" 499source "kernel/bpf/Kconfig" 500source "kernel/Kconfig.preempt" 501 502menu "CPU/Task time and stats accounting" 503 504config VIRT_CPU_ACCOUNTING 505 bool 506 507choice 508 prompt "Cputime accounting" 509 default TICK_CPU_ACCOUNTING 510 511# Kind of a stub config for the pure tick based cputime accounting 512config TICK_CPU_ACCOUNTING 513 bool "Simple tick based cputime accounting" 514 depends on !S390 && !NO_HZ_FULL 515 help 516 This is the basic tick based cputime accounting that maintains 517 statistics about user, system and idle time spent on per jiffies 518 granularity. 519 520 If unsure, say Y. 521 522config VIRT_CPU_ACCOUNTING_NATIVE 523 bool "Deterministic task and CPU time accounting" 524 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL 525 select VIRT_CPU_ACCOUNTING 526 help 527 Select this option to enable more accurate task and CPU time 528 accounting. This is done by reading a CPU counter on each 529 kernel entry and exit and on transitions within the kernel 530 between system, softirq and hardirq state, so there is a 531 small performance impact. In the case of s390 or IBM POWER > 5, 532 this also enables accounting of stolen time on logically-partitioned 533 systems. 534 535config VIRT_CPU_ACCOUNTING_GEN 536 bool "Full dynticks CPU time accounting" 537 depends on HAVE_CONTEXT_TRACKING_USER 538 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN 539 depends on GENERIC_CLOCKEVENTS 540 select VIRT_CPU_ACCOUNTING 541 select CONTEXT_TRACKING_USER 542 help 543 Select this option to enable task and CPU time accounting on full 544 dynticks systems. This accounting is implemented by watching every 545 kernel-user boundaries using the context tracking subsystem. 546 The accounting is thus performed at the expense of some significant 547 overhead. 548 549 For now this is only useful if you are working on the full 550 dynticks subsystem development. 551 552 If unsure, say N. 553 554endchoice 555 556config IRQ_TIME_ACCOUNTING 557 bool "Fine granularity task level IRQ time accounting" 558 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE 559 help 560 Select this option to enable fine granularity task irq time 561 accounting. This is done by reading a timestamp on each 562 transitions between softirq and hardirq state, so there can be a 563 small performance impact. 564 565 If in doubt, say N here. 566 567config HAVE_SCHED_AVG_IRQ 568 def_bool y 569 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING 570 depends on SMP 571 572config SCHED_HW_PRESSURE 573 bool 574 default y if ARM && ARM_CPU_TOPOLOGY 575 default y if ARM64 576 depends on SMP 577 depends on CPU_FREQ_THERMAL 578 help 579 Select this option to enable HW pressure accounting in the 580 scheduler. HW pressure is the value conveyed to the scheduler 581 that reflects the reduction in CPU compute capacity resulted from 582 HW throttling. HW throttling occurs when the performance of 583 a CPU is capped due to high operating temperatures as an example. 584 585 If selected, the scheduler will be able to balance tasks accordingly, 586 i.e. put less load on throttled CPUs than on non/less throttled ones. 587 588 This requires the architecture to implement 589 arch_update_hw_pressure() and arch_scale_thermal_pressure(). 590 591config BSD_PROCESS_ACCT 592 bool "BSD Process Accounting" 593 depends on MULTIUSER 594 help 595 If you say Y here, a user level program will be able to instruct the 596 kernel (via a special system call) to write process accounting 597 information to a file: whenever a process exits, information about 598 that process will be appended to the file by the kernel. The 599 information includes things such as creation time, owning user, 600 command name, memory usage, controlling terminal etc. (the complete 601 list is in the struct acct in <file:include/linux/acct.h>). It is 602 up to the user level program to do useful things with this 603 information. This is generally a good idea, so say Y. 604 605config BSD_PROCESS_ACCT_V3 606 bool "BSD Process Accounting version 3 file format" 607 depends on BSD_PROCESS_ACCT 608 default n 609 help 610 If you say Y here, the process accounting information is written 611 in a new file format that also logs the process IDs of each 612 process and its parent. Note that this file format is incompatible 613 with previous v0/v1/v2 file formats, so you will need updated tools 614 for processing it. A preliminary version of these tools is available 615 at <http://www.gnu.org/software/acct/>. 616 617config TASKSTATS 618 bool "Export task/process statistics through netlink" 619 depends on NET 620 depends on MULTIUSER 621 default n 622 help 623 Export selected statistics for tasks/processes through the 624 generic netlink interface. Unlike BSD process accounting, the 625 statistics are available during the lifetime of tasks/processes as 626 responses to commands. Like BSD accounting, they are sent to user 627 space on task exit. 628 629 Say N if unsure. 630 631config TASK_DELAY_ACCT 632 bool "Enable per-task delay accounting" 633 depends on TASKSTATS 634 select SCHED_INFO 635 help 636 Collect information on time spent by a task waiting for system 637 resources like cpu, synchronous block I/O completion and swapping 638 in pages. Such statistics can help in setting a task's priorities 639 relative to other tasks for cpu, io, rss limits etc. 640 641 Say N if unsure. 642 643config TASK_XACCT 644 bool "Enable extended accounting over taskstats" 645 depends on TASKSTATS 646 help 647 Collect extended task accounting data and send the data 648 to userland for processing over the taskstats interface. 649 650 Say N if unsure. 651 652config TASK_IO_ACCOUNTING 653 bool "Enable per-task storage I/O accounting" 654 depends on TASK_XACCT 655 help 656 Collect information on the number of bytes of storage I/O which this 657 task has caused. 658 659 Say N if unsure. 660 661config PSI 662 bool "Pressure stall information tracking" 663 select KERNFS 664 help 665 Collect metrics that indicate how overcommitted the CPU, memory, 666 and IO capacity are in the system. 667 668 If you say Y here, the kernel will create /proc/pressure/ with the 669 pressure statistics files cpu, memory, and io. These will indicate 670 the share of walltime in which some or all tasks in the system are 671 delayed due to contention of the respective resource. 672 673 In kernels with cgroup support, cgroups (cgroup2 only) will 674 have cpu.pressure, memory.pressure, and io.pressure files, 675 which aggregate pressure stalls for the grouped tasks only. 676 677 For more details see Documentation/accounting/psi.rst. 678 679 Say N if unsure. 680 681config PSI_DEFAULT_DISABLED 682 bool "Require boot parameter to enable pressure stall information tracking" 683 default n 684 depends on PSI 685 help 686 If set, pressure stall information tracking will be disabled 687 per default but can be enabled through passing psi=1 on the 688 kernel commandline during boot. 689 690 This feature adds some code to the task wakeup and sleep 691 paths of the scheduler. The overhead is too low to affect 692 common scheduling-intense workloads in practice (such as 693 webservers, memcache), but it does show up in artificial 694 scheduler stress tests, such as hackbench. 695 696 If you are paranoid and not sure what the kernel will be 697 used for, say Y. 698 699 Say N if unsure. 700 701endmenu # "CPU/Task time and stats accounting" 702 703config CPU_ISOLATION 704 bool "CPU isolation" 705 depends on SMP 706 default y 707 help 708 Make sure that CPUs running critical tasks are not disturbed by 709 any source of "noise" such as unbound workqueues, timers, kthreads... 710 Unbound jobs get offloaded to housekeeping CPUs. This is driven by 711 the "isolcpus=" boot parameter. 712 713 Say Y if unsure. 714 715source "kernel/rcu/Kconfig" 716 717config IKCONFIG 718 tristate "Kernel .config support" 719 help 720 This option enables the complete Linux kernel ".config" file 721 contents to be saved in the kernel. It provides documentation 722 of which kernel options are used in a running kernel or in an 723 on-disk kernel. This information can be extracted from the kernel 724 image file with the script scripts/extract-ikconfig and used as 725 input to rebuild the current kernel or to build another kernel. 726 It can also be extracted from a running kernel by reading 727 /proc/config.gz if enabled (below). 728 729config IKCONFIG_PROC 730 bool "Enable access to .config through /proc/config.gz" 731 depends on IKCONFIG && PROC_FS 732 help 733 This option enables access to the kernel configuration file 734 through /proc/config.gz. 735 736config IKHEADERS 737 tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz" 738 depends on SYSFS 739 help 740 This option enables access to the in-kernel headers that are generated during 741 the build process. These can be used to build eBPF tracing programs, 742 or similar programs. If you build the headers as a module, a module called 743 kheaders.ko is built which can be loaded on-demand to get access to headers. 744 745config LOG_BUF_SHIFT 746 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 747 range 12 25 748 default 17 749 depends on PRINTK 750 help 751 Select the minimal kernel log buffer size as a power of 2. 752 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config 753 parameter, see below. Any higher size also might be forced 754 by "log_buf_len" boot parameter. 755 756 Examples: 757 17 => 128 KB 758 16 => 64 KB 759 15 => 32 KB 760 14 => 16 KB 761 13 => 8 KB 762 12 => 4 KB 763 764config LOG_CPU_MAX_BUF_SHIFT 765 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" 766 depends on SMP 767 range 0 21 768 default 0 if BASE_SMALL 769 default 12 770 depends on PRINTK 771 help 772 This option allows to increase the default ring buffer size 773 according to the number of CPUs. The value defines the contribution 774 of each CPU as a power of 2. The used space is typically only few 775 lines however it might be much more when problems are reported, 776 e.g. backtraces. 777 778 The increased size means that a new buffer has to be allocated and 779 the original static one is unused. It makes sense only on systems 780 with more CPUs. Therefore this value is used only when the sum of 781 contributions is greater than the half of the default kernel ring 782 buffer as defined by LOG_BUF_SHIFT. The default values are set 783 so that more than 16 CPUs are needed to trigger the allocation. 784 785 Also this option is ignored when "log_buf_len" kernel parameter is 786 used as it forces an exact (power of two) size of the ring buffer. 787 788 The number of possible CPUs is used for this computation ignoring 789 hotplugging making the computation optimal for the worst case 790 scenario while allowing a simple algorithm to be used from bootup. 791 792 Examples shift values and their meaning: 793 17 => 128 KB for each CPU 794 16 => 64 KB for each CPU 795 15 => 32 KB for each CPU 796 14 => 16 KB for each CPU 797 13 => 8 KB for each CPU 798 12 => 4 KB for each CPU 799 800config PRINTK_INDEX 801 bool "Printk indexing debugfs interface" 802 depends on PRINTK && DEBUG_FS 803 help 804 Add support for indexing of all printk formats known at compile time 805 at <debugfs>/printk/index/<module>. 806 807 This can be used as part of maintaining daemons which monitor 808 /dev/kmsg, as it permits auditing the printk formats present in a 809 kernel, allowing detection of cases where monitored printks are 810 changed or no longer present. 811 812 There is no additional runtime cost to printk with this enabled. 813 814# 815# Architectures with an unreliable sched_clock() should select this: 816# 817config HAVE_UNSTABLE_SCHED_CLOCK 818 bool 819 820config GENERIC_SCHED_CLOCK 821 bool 822 823menu "Scheduler features" 824 825config UCLAMP_TASK 826 bool "Enable utilization clamping for RT/FAIR tasks" 827 depends on CPU_FREQ_GOV_SCHEDUTIL 828 help 829 This feature enables the scheduler to track the clamped utilization 830 of each CPU based on RUNNABLE tasks scheduled on that CPU. 831 832 With this option, the user can specify the min and max CPU 833 utilization allowed for RUNNABLE tasks. The max utilization defines 834 the maximum frequency a task should use while the min utilization 835 defines the minimum frequency it should use. 836 837 Both min and max utilization clamp values are hints to the scheduler, 838 aiming at improving its frequency selection policy, but they do not 839 enforce or grant any specific bandwidth for tasks. 840 841 If in doubt, say N. 842 843config UCLAMP_BUCKETS_COUNT 844 int "Number of supported utilization clamp buckets" 845 range 5 20 846 default 5 847 depends on UCLAMP_TASK 848 help 849 Defines the number of clamp buckets to use. The range of each bucket 850 will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the 851 number of clamp buckets the finer their granularity and the higher 852 the precision of clamping aggregation and tracking at run-time. 853 854 For example, with the minimum configuration value we will have 5 855 clamp buckets tracking 20% utilization each. A 25% boosted tasks will 856 be refcounted in the [20..39]% bucket and will set the bucket clamp 857 effective value to 25%. 858 If a second 30% boosted task should be co-scheduled on the same CPU, 859 that task will be refcounted in the same bucket of the first task and 860 it will boost the bucket clamp effective value to 30%. 861 The clamp effective value of a bucket is reset to its nominal value 862 (20% in the example above) when there are no more tasks refcounted in 863 that bucket. 864 865 An additional boost/capping margin can be added to some tasks. In the 866 example above the 25% task will be boosted to 30% until it exits the 867 CPU. If that should be considered not acceptable on certain systems, 868 it's always possible to reduce the margin by increasing the number of 869 clamp buckets to trade off used memory for run-time tracking 870 precision. 871 872 If in doubt, use the default value. 873 874endmenu 875 876# 877# For architectures that want to enable the support for NUMA-affine scheduler 878# balancing logic: 879# 880config ARCH_SUPPORTS_NUMA_BALANCING 881 bool 882 883# 884# For architectures that prefer to flush all TLBs after a number of pages 885# are unmapped instead of sending one IPI per page to flush. The architecture 886# must provide guarantees on what happens if a clean TLB cache entry is 887# written after the unmap. Details are in mm/rmap.c near the check for 888# should_defer_flush. The architecture should also consider if the full flush 889# and the refill costs are offset by the savings of sending fewer IPIs. 890config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 891 bool 892 893config CC_HAS_INT128 894 def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT 895 896config CC_IMPLICIT_FALLTHROUGH 897 string 898 default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) 899 default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) 900 901# Currently, disable gcc-10+ array-bounds globally. 902# It's still broken in gcc-13, so no upper bound yet. 903config GCC10_NO_ARRAY_BOUNDS 904 def_bool y 905 906config CC_NO_ARRAY_BOUNDS 907 bool 908 default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC10_NO_ARRAY_BOUNDS 909 910# Currently, disable -Wstringop-overflow for GCC globally. 911config GCC_NO_STRINGOP_OVERFLOW 912 def_bool y 913 914config CC_NO_STRINGOP_OVERFLOW 915 bool 916 default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW 917 918config CC_STRINGOP_OVERFLOW 919 bool 920 default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW 921 922# 923# For architectures that know their GCC __int128 support is sound 924# 925config ARCH_SUPPORTS_INT128 926 bool 927 928# For architectures that (ab)use NUMA to represent different memory regions 929# all cpu-local but of different latencies, such as SuperH. 930# 931config ARCH_WANT_NUMA_VARIABLE_LOCALITY 932 bool 933 934config NUMA_BALANCING 935 bool "Memory placement aware NUMA scheduler" 936 depends on ARCH_SUPPORTS_NUMA_BALANCING 937 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY 938 depends on SMP && NUMA && MIGRATION && !PREEMPT_RT 939 help 940 This option adds support for automatic NUMA aware memory/task placement. 941 The mechanism is quite primitive and is based on migrating memory when 942 it has references to the node the task is running on. 943 944 This system will be inactive on UMA systems. 945 946config NUMA_BALANCING_DEFAULT_ENABLED 947 bool "Automatically enable NUMA aware memory/task placement" 948 default y 949 depends on NUMA_BALANCING 950 help 951 If set, automatic NUMA balancing will be enabled if running on a NUMA 952 machine. 953 954config SLAB_OBJ_EXT 955 bool 956 957menuconfig CGROUPS 958 bool "Control Group support" 959 select KERNFS 960 help 961 This option adds support for grouping sets of processes together, for 962 use with process control subsystems such as Cpusets, CFS, memory 963 controls or device isolation. 964 See 965 - Documentation/scheduler/sched-design-CFS.rst (CFS) 966 - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation 967 and resource control) 968 969 Say N if unsure. 970 971if CGROUPS 972 973config PAGE_COUNTER 974 bool 975 976config CGROUP_FAVOR_DYNMODS 977 bool "Favor dynamic modification latency reduction by default" 978 help 979 This option enables the "favordynmods" mount option by default 980 which reduces the latencies of dynamic cgroup modifications such 981 as task migrations and controller on/offs at the cost of making 982 hot path operations such as forks and exits more expensive. 983 984 Say N if unsure. 985 986config MEMCG 987 bool "Memory controller" 988 select PAGE_COUNTER 989 select EVENTFD 990 select SLAB_OBJ_EXT 991 help 992 Provides control over the memory footprint of tasks in a cgroup. 993 994config MEMCG_V1 995 bool "Legacy cgroup v1 memory controller" 996 depends on MEMCG 997 default n 998 help 999 Legacy cgroup v1 memory controller which has been deprecated by 1000 cgroup v2 implementation. The v1 is there for legacy applications 1001 which haven't migrated to the new cgroup v2 interface yet. If you 1002 do not have any such application then you are completely fine leaving 1003 this option disabled. 1004 1005 Please note that feature set of the legacy memory controller is likely 1006 going to shrink due to deprecation process. New deployments with v1 1007 controller are highly discouraged. 1008 1009 Say N if unsure. 1010 1011config BLK_CGROUP 1012 bool "IO controller" 1013 depends on BLOCK 1014 default n 1015 help 1016 Generic block IO controller cgroup interface. This is the common 1017 cgroup interface which should be used by various IO controlling 1018 policies. 1019 1020 Currently, CFQ IO scheduler uses it to recognize task groups and 1021 control disk bandwidth allocation (proportional time slice allocation) 1022 to such task groups. It is also used by bio throttling logic in 1023 block layer to implement upper limit in IO rates on a device. 1024 1025 This option only enables generic Block IO controller infrastructure. 1026 One needs to also enable actual IO controlling logic/policy. For 1027 enabling proportional weight division of disk bandwidth in CFQ, set 1028 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 1029 CONFIG_BLK_DEV_THROTTLING=y. 1030 1031 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information. 1032 1033config CGROUP_WRITEBACK 1034 bool 1035 depends on MEMCG && BLK_CGROUP 1036 default y 1037 1038menuconfig CGROUP_SCHED 1039 bool "CPU controller" 1040 default n 1041 help 1042 This feature lets CPU scheduler recognize task groups and control CPU 1043 bandwidth allocation to such task groups. It uses cgroups to group 1044 tasks. 1045 1046if CGROUP_SCHED 1047config GROUP_SCHED_WEIGHT 1048 def_bool n 1049 1050config FAIR_GROUP_SCHED 1051 bool "Group scheduling for SCHED_OTHER" 1052 depends on CGROUP_SCHED 1053 select GROUP_SCHED_WEIGHT 1054 default CGROUP_SCHED 1055 1056config CFS_BANDWIDTH 1057 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 1058 depends on FAIR_GROUP_SCHED 1059 default n 1060 help 1061 This option allows users to define CPU bandwidth rates (limits) for 1062 tasks running within the fair group scheduler. Groups with no limit 1063 set are considered to be unconstrained and will run with no 1064 restriction. 1065 See Documentation/scheduler/sched-bwc.rst for more information. 1066 1067config RT_GROUP_SCHED 1068 bool "Group scheduling for SCHED_RR/FIFO" 1069 depends on CGROUP_SCHED 1070 default n 1071 help 1072 This feature lets you explicitly allocate real CPU bandwidth 1073 to task groups. If enabled, it will also make it impossible to 1074 schedule realtime tasks for non-root users until you allocate 1075 realtime bandwidth for them. 1076 See Documentation/scheduler/sched-rt-group.rst for more information. 1077 1078config RT_GROUP_SCHED_DEFAULT_DISABLED 1079 bool "Require boot parameter to enable group scheduling for SCHED_RR/FIFO" 1080 depends on RT_GROUP_SCHED 1081 default n 1082 help 1083 When set, the RT group scheduling is disabled by default. The option 1084 is in inverted form so that mere RT_GROUP_SCHED enables the group 1085 scheduling. 1086 1087 Say N if unsure. 1088 1089config EXT_GROUP_SCHED 1090 bool 1091 depends on SCHED_CLASS_EXT && CGROUP_SCHED 1092 select GROUP_SCHED_WEIGHT 1093 default y 1094 1095endif #CGROUP_SCHED 1096 1097config SCHED_MM_CID 1098 def_bool y 1099 depends on SMP && RSEQ 1100 1101config UCLAMP_TASK_GROUP 1102 bool "Utilization clamping per group of tasks" 1103 depends on CGROUP_SCHED 1104 depends on UCLAMP_TASK 1105 default n 1106 help 1107 This feature enables the scheduler to track the clamped utilization 1108 of each CPU based on RUNNABLE tasks currently scheduled on that CPU. 1109 1110 When this option is enabled, the user can specify a min and max 1111 CPU bandwidth which is allowed for each single task in a group. 1112 The max bandwidth allows to clamp the maximum frequency a task 1113 can use, while the min bandwidth allows to define a minimum 1114 frequency a task will always use. 1115 1116 When task group based utilization clamping is enabled, an eventually 1117 specified task-specific clamp value is constrained by the cgroup 1118 specified clamp value. Both minimum and maximum task clamping cannot 1119 be bigger than the corresponding clamping defined at task group level. 1120 1121 If in doubt, say N. 1122 1123config CGROUP_PIDS 1124 bool "PIDs controller" 1125 help 1126 Provides enforcement of process number limits in the scope of a 1127 cgroup. Any attempt to fork more processes than is allowed in the 1128 cgroup will fail. PIDs are fundamentally a global resource because it 1129 is fairly trivial to reach PID exhaustion before you reach even a 1130 conservative kmemcg limit. As a result, it is possible to grind a 1131 system to halt without being limited by other cgroup policies. The 1132 PIDs controller is designed to stop this from happening. 1133 1134 It should be noted that organisational operations (such as attaching 1135 to a cgroup hierarchy) will *not* be blocked by the PIDs controller, 1136 since the PIDs limit only affects a process's ability to fork, not to 1137 attach to a cgroup. 1138 1139config CGROUP_RDMA 1140 bool "RDMA controller" 1141 help 1142 Provides enforcement of RDMA resources defined by IB stack. 1143 It is fairly easy for consumers to exhaust RDMA resources, which 1144 can result into resource unavailability to other consumers. 1145 RDMA controller is designed to stop this from happening. 1146 Attaching processes with active RDMA resources to the cgroup 1147 hierarchy is allowed even if can cross the hierarchy's limit. 1148 1149config CGROUP_DMEM 1150 bool "Device memory controller (DMEM)" 1151 select PAGE_COUNTER 1152 help 1153 The DMEM controller allows compatible devices to restrict device 1154 memory usage based on the cgroup hierarchy. 1155 1156 As an example, it allows you to restrict VRAM usage for applications 1157 in the DRM subsystem. 1158 1159config CGROUP_FREEZER 1160 bool "Freezer controller" 1161 help 1162 Provides a way to freeze and unfreeze all tasks in a 1163 cgroup. 1164 1165 This option affects the ORIGINAL cgroup interface. The cgroup2 memory 1166 controller includes important in-kernel memory consumers per default. 1167 1168 If you're using cgroup2, say N. 1169 1170config CGROUP_HUGETLB 1171 bool "HugeTLB controller" 1172 depends on HUGETLB_PAGE 1173 select PAGE_COUNTER 1174 default n 1175 help 1176 Provides a cgroup controller for HugeTLB pages. 1177 When you enable this, you can put a per cgroup limit on HugeTLB usage. 1178 The limit is enforced during page fault. Since HugeTLB doesn't 1179 support page reclaim, enforcing the limit at page fault time implies 1180 that, the application will get SIGBUS signal if it tries to access 1181 HugeTLB pages beyond its limit. This requires the application to know 1182 beforehand how much HugeTLB pages it would require for its use. The 1183 control group is tracked in the third page lru pointer. This means 1184 that we cannot use the controller with huge page less than 3 pages. 1185 1186config CPUSETS 1187 bool "Cpuset controller" 1188 depends on SMP 1189 select UNION_FIND 1190 help 1191 This option will let you create and manage CPUSETs which 1192 allow dynamically partitioning a system into sets of CPUs and 1193 Memory Nodes and assigning tasks to run only within those sets. 1194 This is primarily useful on large SMP or NUMA systems. 1195 1196 Say N if unsure. 1197 1198config CPUSETS_V1 1199 bool "Legacy cgroup v1 cpusets controller" 1200 depends on CPUSETS 1201 default n 1202 help 1203 Legacy cgroup v1 cpusets controller which has been deprecated by 1204 cgroup v2 implementation. The v1 is there for legacy applications 1205 which haven't migrated to the new cgroup v2 interface yet. Legacy 1206 interface includes cpuset filesystem and /proc/<pid>/cpuset. If you 1207 do not have any such application then you are completely fine leaving 1208 this option disabled. 1209 1210 Say N if unsure. 1211 1212config PROC_PID_CPUSET 1213 bool "Include legacy /proc/<pid>/cpuset file" 1214 depends on CPUSETS_V1 1215 default y 1216 1217config CGROUP_DEVICE 1218 bool "Device controller" 1219 help 1220 Provides a cgroup controller implementing whitelists for 1221 devices which a process in the cgroup can mknod or open. 1222 1223config CGROUP_CPUACCT 1224 bool "Simple CPU accounting controller" 1225 help 1226 Provides a simple controller for monitoring the 1227 total CPU consumed by the tasks in a cgroup. 1228 1229config CGROUP_PERF 1230 bool "Perf controller" 1231 depends on PERF_EVENTS 1232 help 1233 This option extends the perf per-cpu mode to restrict monitoring 1234 to threads which belong to the cgroup specified and run on the 1235 designated cpu. Or this can be used to have cgroup ID in samples 1236 so that it can monitor performance events among cgroups. 1237 1238 Say N if unsure. 1239 1240config CGROUP_BPF 1241 bool "Support for eBPF programs attached to cgroups" 1242 depends on BPF_SYSCALL 1243 select SOCK_CGROUP_DATA 1244 help 1245 Allow attaching eBPF programs to a cgroup using the bpf(2) 1246 syscall command BPF_PROG_ATTACH. 1247 1248 In which context these programs are accessed depends on the type 1249 of attachment. For instance, programs that are attached using 1250 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of 1251 inet sockets. 1252 1253config CGROUP_MISC 1254 bool "Misc resource controller" 1255 default n 1256 help 1257 Provides a controller for miscellaneous resources on a host. 1258 1259 Miscellaneous scalar resources are the resources on the host system 1260 which cannot be abstracted like the other cgroups. This controller 1261 tracks and limits the miscellaneous resources used by a process 1262 attached to a cgroup hierarchy. 1263 1264 For more information, please check misc cgroup section in 1265 /Documentation/admin-guide/cgroup-v2.rst. 1266 1267config CGROUP_DEBUG 1268 bool "Debug controller" 1269 default n 1270 depends on DEBUG_KERNEL 1271 help 1272 This option enables a simple controller that exports 1273 debugging information about the cgroups framework. This 1274 controller is for control cgroup debugging only. Its 1275 interfaces are not stable. 1276 1277 Say N. 1278 1279config SOCK_CGROUP_DATA 1280 bool 1281 default n 1282 1283endif # CGROUPS 1284 1285menuconfig NAMESPACES 1286 bool "Namespaces support" if EXPERT 1287 depends on MULTIUSER 1288 default !EXPERT 1289 help 1290 Provides the way to make tasks work with different objects using 1291 the same id. For example same IPC id may refer to different objects 1292 or same user id or pid may refer to different tasks when used in 1293 different namespaces. 1294 1295if NAMESPACES 1296 1297config UTS_NS 1298 bool "UTS namespace" 1299 default y 1300 help 1301 In this namespace tasks see different info provided with the 1302 uname() system call 1303 1304config TIME_NS 1305 bool "TIME namespace" 1306 depends on GENERIC_VDSO_TIME_NS 1307 default y 1308 help 1309 In this namespace boottime and monotonic clocks can be set. 1310 The time will keep going with the same pace. 1311 1312config IPC_NS 1313 bool "IPC namespace" 1314 depends on (SYSVIPC || POSIX_MQUEUE) 1315 default y 1316 help 1317 In this namespace tasks work with IPC ids which correspond to 1318 different IPC objects in different namespaces. 1319 1320config USER_NS 1321 bool "User namespace" 1322 default n 1323 help 1324 This allows containers, i.e. vservers, to use user namespaces 1325 to provide different user info for different servers. 1326 1327 When user namespaces are enabled in the kernel it is 1328 recommended that the MEMCG option also be enabled and that 1329 user-space use the memory control groups to limit the amount 1330 of memory a memory unprivileged users can use. 1331 1332 If unsure, say N. 1333 1334config PID_NS 1335 bool "PID Namespaces" 1336 default y 1337 help 1338 Support process id namespaces. This allows having multiple 1339 processes with the same pid as long as they are in different 1340 pid namespaces. This is a building block of containers. 1341 1342config NET_NS 1343 bool "Network namespace" 1344 depends on NET 1345 default y 1346 help 1347 Allow user space to create what appear to be multiple instances 1348 of the network stack. 1349 1350endif # NAMESPACES 1351 1352config CHECKPOINT_RESTORE 1353 bool "Checkpoint/restore support" 1354 depends on PROC_FS 1355 select PROC_CHILDREN 1356 select KCMP 1357 default n 1358 help 1359 Enables additional kernel features in a sake of checkpoint/restore. 1360 In particular it adds auxiliary prctl codes to setup process text, 1361 data and heap segment sizes, and a few additional /proc filesystem 1362 entries. 1363 1364 If unsure, say N here. 1365 1366config SCHED_AUTOGROUP 1367 bool "Automatic process group scheduling" 1368 select CGROUPS 1369 select CGROUP_SCHED 1370 select FAIR_GROUP_SCHED 1371 help 1372 This option optimizes the scheduler for common desktop workloads by 1373 automatically creating and populating task groups. This separation 1374 of workloads isolates aggressive CPU burners (like build jobs) from 1375 desktop applications. Task group autogeneration is currently based 1376 upon task session. 1377 1378config RELAY 1379 bool "Kernel->user space relay support (formerly relayfs)" 1380 select IRQ_WORK 1381 help 1382 This option enables support for relay interface support in 1383 certain file systems (such as debugfs). 1384 It is designed to provide an efficient mechanism for tools and 1385 facilities to relay large amounts of data from kernel space to 1386 user space. 1387 1388 If unsure, say N. 1389 1390config BLK_DEV_INITRD 1391 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1392 help 1393 The initial RAM filesystem is a ramfs which is loaded by the 1394 boot loader (loadlin or lilo) and that is mounted as root 1395 before the normal boot procedure. It is typically used to 1396 load modules needed to mount the "real" root file system, 1397 etc. See <file:Documentation/admin-guide/initrd.rst> for details. 1398 1399 If RAM disk support (BLK_DEV_RAM) is also included, this 1400 also enables initial RAM disk (initrd) support and adds 1401 15 Kbytes (more on some other architectures) to the kernel size. 1402 1403 If unsure say Y. 1404 1405if BLK_DEV_INITRD 1406 1407source "usr/Kconfig" 1408 1409endif 1410 1411config BOOT_CONFIG 1412 bool "Boot config support" 1413 select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED 1414 help 1415 Extra boot config allows system admin to pass a config file as 1416 complemental extension of kernel cmdline when booting. 1417 The boot config file must be attached at the end of initramfs 1418 with checksum, size and magic word. 1419 See <file:Documentation/admin-guide/bootconfig.rst> for details. 1420 1421 If unsure, say Y. 1422 1423config BOOT_CONFIG_FORCE 1424 bool "Force unconditional bootconfig processing" 1425 depends on BOOT_CONFIG 1426 default y if BOOT_CONFIG_EMBED 1427 help 1428 With this Kconfig option set, BOOT_CONFIG processing is carried 1429 out even when the "bootconfig" kernel-boot parameter is omitted. 1430 In fact, with this Kconfig option set, there is no way to 1431 make the kernel ignore the BOOT_CONFIG-supplied kernel-boot 1432 parameters. 1433 1434 If unsure, say N. 1435 1436config BOOT_CONFIG_EMBED 1437 bool "Embed bootconfig file in the kernel" 1438 depends on BOOT_CONFIG 1439 help 1440 Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the 1441 kernel. Usually, the bootconfig file is loaded with the initrd 1442 image. But if the system doesn't support initrd, this option will 1443 help you by embedding a bootconfig file while building the kernel. 1444 1445 If unsure, say N. 1446 1447config BOOT_CONFIG_EMBED_FILE 1448 string "Embedded bootconfig file path" 1449 depends on BOOT_CONFIG_EMBED 1450 help 1451 Specify a bootconfig file which will be embedded to the kernel. 1452 This bootconfig will be used if there is no initrd or no other 1453 bootconfig in the initrd. 1454 1455config INITRAMFS_PRESERVE_MTIME 1456 bool "Preserve cpio archive mtimes in initramfs" 1457 default y 1458 help 1459 Each entry in an initramfs cpio archive carries an mtime value. When 1460 enabled, extracted cpio items take this mtime, with directory mtime 1461 setting deferred until after creation of any child entries. 1462 1463 If unsure, say Y. 1464 1465config INITRAMFS_TEST 1466 bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS 1467 depends on BLK_DEV_INITRD && KUNIT=y 1468 default KUNIT_ALL_TESTS 1469 help 1470 Build KUnit tests for initramfs. See Documentation/dev-tools/kunit 1471 1472choice 1473 prompt "Compiler optimization level" 1474 default CC_OPTIMIZE_FOR_PERFORMANCE 1475 1476config CC_OPTIMIZE_FOR_PERFORMANCE 1477 bool "Optimize for performance (-O2)" 1478 help 1479 This is the default optimization level for the kernel, building 1480 with the "-O2" compiler flag for best performance and most 1481 helpful compile-time warnings. 1482 1483config CC_OPTIMIZE_FOR_SIZE 1484 bool "Optimize for size (-Os)" 1485 help 1486 Choosing this option will pass "-Os" to your compiler resulting 1487 in a smaller kernel. 1488 1489endchoice 1490 1491config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1492 bool 1493 help 1494 This requires that the arch annotates or otherwise protects 1495 its external entry points from being discarded. Linker scripts 1496 must also merge .text.*, .data.*, and .bss.* correctly into 1497 output sections. Care must be taken not to pull in unrelated 1498 sections (e.g., '.text.init'). Typically '.' in section names 1499 is used to distinguish them from label names / C identifiers. 1500 1501config LD_DEAD_CODE_DATA_ELIMINATION 1502 bool "Dead code and data elimination (EXPERIMENTAL)" 1503 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1504 depends on EXPERT 1505 depends on $(cc-option,-ffunction-sections -fdata-sections) 1506 depends on $(ld-option,--gc-sections) 1507 help 1508 Enable this if you want to do dead code and data elimination with 1509 the linker by compiling with -ffunction-sections -fdata-sections, 1510 and linking with --gc-sections. 1511 1512 This can reduce on disk and in-memory size of the kernel 1513 code and static data, particularly for small configs and 1514 on small systems. This has the possibility of introducing 1515 silently broken kernel if the required annotations are not 1516 present. This option is not well tested yet, so use at your 1517 own risk. 1518 1519config LD_ORPHAN_WARN 1520 def_bool y 1521 depends on ARCH_WANT_LD_ORPHAN_WARN 1522 depends on $(ld-option,--orphan-handling=warn) 1523 depends on $(ld-option,--orphan-handling=error) 1524 1525config LD_ORPHAN_WARN_LEVEL 1526 string 1527 depends on LD_ORPHAN_WARN 1528 default "error" if WERROR 1529 default "warn" 1530 1531config SYSCTL 1532 bool 1533 1534config HAVE_UID16 1535 bool 1536 1537config SYSCTL_EXCEPTION_TRACE 1538 bool 1539 help 1540 Enable support for /proc/sys/debug/exception-trace. 1541 1542config SYSCTL_ARCH_UNALIGN_NO_WARN 1543 bool 1544 help 1545 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1546 Allows arch to define/use @no_unaligned_warning to possibly warn 1547 about unaligned access emulation going on under the hood. 1548 1549config SYSCTL_ARCH_UNALIGN_ALLOW 1550 bool 1551 help 1552 Enable support for /proc/sys/kernel/unaligned-trap 1553 Allows arches to define/use @unaligned_enabled to runtime toggle 1554 the unaligned access emulation. 1555 see arch/parisc/kernel/unaligned.c for reference 1556 1557config SYSFS_SYSCALL 1558 bool "Sysfs syscall support" 1559 default n 1560 help 1561 sys_sysfs is an obsolete system call no longer supported in libc. 1562 Note that disabling this option is more secure but might break 1563 compatibility with some systems. 1564 1565 If unsure say N here. 1566 1567config HAVE_PCSPKR_PLATFORM 1568 bool 1569 1570menuconfig EXPERT 1571 bool "Configure standard kernel features (expert users)" 1572 # Unhide debug options, to make the on-by-default options visible 1573 select DEBUG_KERNEL 1574 help 1575 This option allows certain base kernel options and settings 1576 to be disabled or tweaked. This is for specialized 1577 environments which can tolerate a "non-standard" kernel. 1578 Only use this if you really know what you are doing. 1579 1580config UID16 1581 bool "Enable 16-bit UID system calls" if EXPERT 1582 depends on HAVE_UID16 && MULTIUSER 1583 default y 1584 help 1585 This enables the legacy 16-bit UID syscall wrappers. 1586 1587config MULTIUSER 1588 bool "Multiple users, groups and capabilities support" if EXPERT 1589 default y 1590 help 1591 This option enables support for non-root users, groups and 1592 capabilities. 1593 1594 If you say N here, all processes will run with UID 0, GID 0, and all 1595 possible capabilities. Saying N here also compiles out support for 1596 system calls related to UIDs, GIDs, and capabilities, such as setuid, 1597 setgid, and capset. 1598 1599 If unsure, say Y here. 1600 1601config SGETMASK_SYSCALL 1602 bool "sgetmask/ssetmask syscalls support" if EXPERT 1603 default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH 1604 help 1605 sys_sgetmask and sys_ssetmask are obsolete system calls 1606 no longer supported in libc but still enabled by default in some 1607 architectures. 1608 1609 If unsure, leave the default option here. 1610 1611config FHANDLE 1612 bool "open by fhandle syscalls" if EXPERT 1613 select EXPORTFS 1614 default y 1615 help 1616 If you say Y here, a user level program will be able to map 1617 file names to handle and then later use the handle for 1618 different file system operations. This is useful in implementing 1619 userspace file servers, which now track files using handles instead 1620 of names. The handle would remain the same even if file names 1621 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 1622 syscalls. 1623 1624config POSIX_TIMERS 1625 bool "Posix Clocks & timers" if EXPERT 1626 default y 1627 help 1628 This includes native support for POSIX timers to the kernel. 1629 Some embedded systems have no use for them and therefore they 1630 can be configured out to reduce the size of the kernel image. 1631 1632 When this option is disabled, the following syscalls won't be 1633 available: timer_create, timer_gettime: timer_getoverrun, 1634 timer_settime, timer_delete, clock_adjtime, getitimer, 1635 setitimer, alarm. Furthermore, the clock_settime, clock_gettime, 1636 clock_getres and clock_nanosleep syscalls will be limited to 1637 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. 1638 1639 If unsure say y. 1640 1641config PRINTK 1642 default y 1643 bool "Enable support for printk" if EXPERT 1644 select IRQ_WORK 1645 help 1646 This option enables normal printk support. Removing it 1647 eliminates most of the message strings from the kernel image 1648 and makes the kernel more or less silent. As this makes it 1649 very difficult to diagnose system problems, saying N here is 1650 strongly discouraged. 1651 1652config BUG 1653 bool "BUG() support" if EXPERT 1654 default y 1655 help 1656 Disabling this option eliminates support for BUG and WARN, reducing 1657 the size of your kernel image and potentially quietly ignoring 1658 numerous fatal conditions. You should only consider disabling this 1659 option for embedded systems with no facilities for reporting errors. 1660 Just say Y. 1661 1662config ELF_CORE 1663 depends on COREDUMP 1664 default y 1665 bool "Enable ELF core dumps" if EXPERT 1666 help 1667 Enable support for generating core dumps. Disabling saves about 4k. 1668 1669 1670config PCSPKR_PLATFORM 1671 bool "Enable PC-Speaker support" if EXPERT 1672 depends on HAVE_PCSPKR_PLATFORM 1673 select I8253_LOCK 1674 default y 1675 help 1676 This option allows to disable the internal PC-Speaker 1677 support, saving some memory. 1678 1679config BASE_SMALL 1680 bool "Enable smaller-sized data structures for core" if EXPERT 1681 help 1682 Enabling this option reduces the size of miscellaneous core 1683 kernel data structures. This saves memory on small machines, 1684 but may reduce performance. 1685 1686config FUTEX 1687 bool "Enable futex support" if EXPERT 1688 depends on !(SPARC32 && SMP) 1689 default y 1690 imply RT_MUTEXES 1691 help 1692 Disabling this option will cause the kernel to be built without 1693 support for "fast userspace mutexes". The resulting kernel may not 1694 run glibc-based applications correctly. 1695 1696config FUTEX_PI 1697 bool 1698 depends on FUTEX && RT_MUTEXES 1699 default y 1700 1701config FUTEX_PRIVATE_HASH 1702 bool 1703 depends on FUTEX && !BASE_SMALL && MMU 1704 default y 1705 1706config FUTEX_MPOL 1707 bool 1708 depends on FUTEX && NUMA 1709 default y 1710 1711config EPOLL 1712 bool "Enable eventpoll support" if EXPERT 1713 default y 1714 help 1715 Disabling this option will cause the kernel to be built without 1716 support for epoll family of system calls. 1717 1718config SIGNALFD 1719 bool "Enable signalfd() system call" if EXPERT 1720 default y 1721 help 1722 Enable the signalfd() system call that allows to receive signals 1723 on a file descriptor. 1724 1725 If unsure, say Y. 1726 1727config TIMERFD 1728 bool "Enable timerfd() system call" if EXPERT 1729 default y 1730 help 1731 Enable the timerfd() system call that allows to receive timer 1732 events on a file descriptor. 1733 1734 If unsure, say Y. 1735 1736config EVENTFD 1737 bool "Enable eventfd() system call" if EXPERT 1738 default y 1739 help 1740 Enable the eventfd() system call that allows to receive both 1741 kernel notification (ie. KAIO) or userspace notifications. 1742 1743 If unsure, say Y. 1744 1745config SHMEM 1746 bool "Use full shmem filesystem" if EXPERT 1747 default y 1748 depends on MMU 1749 help 1750 The shmem is an internal filesystem used to manage shared memory. 1751 It is backed by swap and manages resource limits. It is also exported 1752 to userspace as tmpfs if TMPFS is enabled. Disabling this 1753 option replaces shmem and tmpfs with the much simpler ramfs code, 1754 which may be appropriate on small systems without swap. 1755 1756config AIO 1757 bool "Enable AIO support" if EXPERT 1758 default y 1759 help 1760 This option enables POSIX asynchronous I/O which may by used 1761 by some high performance threaded applications. Disabling 1762 this option saves about 7k. 1763 1764config IO_URING 1765 bool "Enable IO uring support" if EXPERT 1766 select IO_WQ 1767 default y 1768 help 1769 This option enables support for the io_uring interface, enabling 1770 applications to submit and complete IO through submission and 1771 completion rings that are shared between the kernel and application. 1772 1773config GCOV_PROFILE_URING 1774 bool "Enable GCOV profiling on the io_uring subsystem" 1775 depends on GCOV_KERNEL 1776 help 1777 Enable GCOV profiling on the io_uring subsystem, to facilitate 1778 code coverage testing. 1779 1780 If unsure, say N. 1781 1782 Note that this will have a negative impact on the performance of 1783 the io_uring subsystem, hence this should only be enabled for 1784 specific test purposes. 1785 1786config ADVISE_SYSCALLS 1787 bool "Enable madvise/fadvise syscalls" if EXPERT 1788 default y 1789 help 1790 This option enables the madvise and fadvise syscalls, used by 1791 applications to advise the kernel about their future memory or file 1792 usage, improving performance. If building an embedded system where no 1793 applications use these syscalls, you can disable this option to save 1794 space. 1795 1796config MEMBARRIER 1797 bool "Enable membarrier() system call" if EXPERT 1798 default y 1799 help 1800 Enable the membarrier() system call that allows issuing memory 1801 barriers across all running threads, which can be used to distribute 1802 the cost of user-space memory barriers asymmetrically by transforming 1803 pairs of memory barriers into pairs consisting of membarrier() and a 1804 compiler barrier. 1805 1806 If unsure, say Y. 1807 1808config KCMP 1809 bool "Enable kcmp() system call" if EXPERT 1810 help 1811 Enable the kernel resource comparison system call. It provides 1812 user-space with the ability to compare two processes to see if they 1813 share a common resource, such as a file descriptor or even virtual 1814 memory space. 1815 1816 If unsure, say N. 1817 1818config RSEQ 1819 bool "Enable rseq() system call" if EXPERT 1820 default y 1821 depends on HAVE_RSEQ 1822 select MEMBARRIER 1823 help 1824 Enable the restartable sequences system call. It provides a 1825 user-space cache for the current CPU number value, which 1826 speeds up getting the current CPU number from user-space, 1827 as well as an ABI to speed up user-space operations on 1828 per-CPU data. 1829 1830 If unsure, say Y. 1831 1832config DEBUG_RSEQ 1833 default n 1834 bool "Enable debugging of rseq() system call" if EXPERT 1835 depends on RSEQ && DEBUG_KERNEL 1836 help 1837 Enable extra debugging checks for the rseq system call. 1838 1839 If unsure, say N. 1840 1841config CACHESTAT_SYSCALL 1842 bool "Enable cachestat() system call" if EXPERT 1843 default y 1844 help 1845 Enable the cachestat system call, which queries the page cache 1846 statistics of a file (number of cached pages, dirty pages, 1847 pages marked for writeback, (recently) evicted pages). 1848 1849 If unsure say Y here. 1850 1851config PC104 1852 bool "PC/104 support" if EXPERT 1853 help 1854 Expose PC/104 form factor device drivers and options available for 1855 selection and configuration. Enable this option if your target 1856 machine has a PC/104 bus. 1857 1858config KALLSYMS 1859 bool "Load all symbols for debugging/ksymoops" if EXPERT 1860 default y 1861 help 1862 Say Y here to let the kernel print out symbolic crash information and 1863 symbolic stack backtraces. This increases the size of the kernel 1864 somewhat, as all symbols have to be loaded into the kernel image. 1865 1866config KALLSYMS_SELFTEST 1867 bool "Test the basic functions and performance of kallsyms" 1868 depends on KALLSYMS 1869 default n 1870 help 1871 Test the basic functions and performance of some interfaces, such as 1872 kallsyms_lookup_name. It also calculates the compression rate of the 1873 kallsyms compression algorithm for the current symbol set. 1874 1875 Start self-test automatically after system startup. Suggest executing 1876 "dmesg | grep kallsyms_selftest" to collect test results. "finish" is 1877 displayed in the last line, indicating that the test is complete. 1878 1879config KALLSYMS_ALL 1880 bool "Include all symbols in kallsyms" 1881 depends on DEBUG_KERNEL && KALLSYMS 1882 help 1883 Normally kallsyms only contains the symbols of functions for nicer 1884 OOPS messages and backtraces (i.e., symbols from the text and inittext 1885 sections). This is sufficient for most cases. And only if you want to 1886 enable kernel live patching, or other less common use cases (e.g., 1887 when a debugger is used) all symbols are required (i.e., names of 1888 variables from the data sections, etc). 1889 1890 This option makes sure that all symbols are loaded into the kernel 1891 image (i.e., symbols from all sections) in cost of increased kernel 1892 size (depending on the kernel configuration, it may be 300KiB or 1893 something like this). 1894 1895 Say N unless you really need all symbols, or kernel live patching. 1896 1897# end of the "standard kernel features (expert users)" menu 1898 1899config ARCH_HAS_MEMBARRIER_CALLBACKS 1900 bool 1901 1902config ARCH_HAS_MEMBARRIER_SYNC_CORE 1903 bool 1904 1905config ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 1906 bool 1907 help 1908 Control MSEAL_SYSTEM_MAPPINGS access based on architecture. 1909 1910 A 64-bit kernel is required for the memory sealing feature. 1911 No specific hardware features from the CPU are needed. 1912 1913 To enable this feature, the architecture needs to update their 1914 special mappings calls to include the sealing flag and confirm 1915 that it doesn't unmap/remap system mappings during the life 1916 time of the process. The existence of this flag for an architecture 1917 implies that it does not require the remapping of the system 1918 mappings during process lifetime, so sealing these mappings is safe 1919 from a kernel perspective. 1920 1921 After the architecture enables this, a distribution can set 1922 CONFIG_MSEAL_SYSTEM_MAPPING to manage access to the feature. 1923 1924 For complete descriptions of memory sealing, please see 1925 Documentation/userspace-api/mseal.rst 1926 1927config HAVE_PERF_EVENTS 1928 bool 1929 help 1930 See tools/perf/design.txt for details. 1931 1932config GUEST_PERF_EVENTS 1933 bool 1934 depends on HAVE_PERF_EVENTS 1935 1936config PERF_USE_VMALLOC 1937 bool 1938 help 1939 See tools/perf/design.txt for details 1940 1941menu "Kernel Performance Events And Counters" 1942 1943config PERF_EVENTS 1944 bool "Kernel performance events and counters" 1945 default y if PROFILING 1946 depends on HAVE_PERF_EVENTS 1947 select IRQ_WORK 1948 help 1949 Enable kernel support for various performance events provided 1950 by software and hardware. 1951 1952 Software events are supported either built-in or via the 1953 use of generic tracepoints. 1954 1955 Most modern CPUs support performance events via performance 1956 counter registers. These registers count the number of certain 1957 types of hw events: such as instructions executed, cachemisses 1958 suffered, or branches mis-predicted - without slowing down the 1959 kernel or applications. These registers can also trigger interrupts 1960 when a threshold number of events have passed - and can thus be 1961 used to profile the code that runs on that CPU. 1962 1963 The Linux Performance Event subsystem provides an abstraction of 1964 these software and hardware event capabilities, available via a 1965 system call and used by the "perf" utility in tools/perf/. It 1966 provides per task and per CPU counters, and it provides event 1967 capabilities on top of those. 1968 1969 Say Y if unsure. 1970 1971config DEBUG_PERF_USE_VMALLOC 1972 default n 1973 bool "Debug: use vmalloc to back perf mmap() buffers" 1974 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC 1975 select PERF_USE_VMALLOC 1976 help 1977 Use vmalloc memory to back perf mmap() buffers. 1978 1979 Mostly useful for debugging the vmalloc code on platforms 1980 that don't require it. 1981 1982 Say N if unsure. 1983 1984endmenu 1985 1986config SYSTEM_DATA_VERIFICATION 1987 def_bool n 1988 select SYSTEM_TRUSTED_KEYRING 1989 select KEYS 1990 select CRYPTO 1991 select CRYPTO_RSA 1992 select ASYMMETRIC_KEY_TYPE 1993 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 1994 select ASN1 1995 select OID_REGISTRY 1996 select X509_CERTIFICATE_PARSER 1997 select PKCS7_MESSAGE_PARSER 1998 help 1999 Provide PKCS#7 message verification using the contents of the system 2000 trusted keyring to provide public keys. This then can be used for 2001 module verification, kexec image verification and firmware blob 2002 verification. 2003 2004config PROFILING 2005 bool "Profiling support" 2006 help 2007 Say Y here to enable the extended profiling support mechanisms used 2008 by profilers. 2009 2010config RUST 2011 bool "Rust support" 2012 depends on HAVE_RUST 2013 depends on RUST_IS_AVAILABLE 2014 select EXTENDED_MODVERSIONS if MODVERSIONS 2015 depends on !MODVERSIONS || GENDWARFKSYMS 2016 depends on !GCC_PLUGIN_RANDSTRUCT 2017 depends on !RANDSTRUCT 2018 depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO) 2019 depends on !CFI_CLANG || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC 2020 select CFI_ICALL_NORMALIZE_INTEGERS if CFI_CLANG 2021 depends on !CALL_PADDING || RUSTC_VERSION >= 108100 2022 depends on !KASAN_SW_TAGS 2023 depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300 2024 help 2025 Enables Rust support in the kernel. 2026 2027 This allows other Rust-related options, like drivers written in Rust, 2028 to be selected. 2029 2030 It is also required to be able to load external kernel modules 2031 written in Rust. 2032 2033 See Documentation/rust/ for more information. 2034 2035 If unsure, say N. 2036 2037config RUSTC_VERSION_TEXT 2038 string 2039 depends on RUST 2040 default "$(RUSTC_VERSION_TEXT)" 2041 help 2042 See `CC_VERSION_TEXT`. 2043 2044config BINDGEN_VERSION_TEXT 2045 string 2046 depends on RUST 2047 # The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0 2048 # (https://github.com/rust-lang/rust-bindgen/pull/2678) and 0.71.0 2049 # (https://github.com/rust-lang/rust-bindgen/pull/3040). It can be removed 2050 # when the minimum version is upgraded past the latter (0.69.1 and 0.71.1 2051 # both fixed the issue). 2052 default "$(shell,$(BINDGEN) --version workaround-for-0.69.0 2>/dev/null)" 2053 2054# 2055# Place an empty function call at each tracepoint site. Can be 2056# dynamically changed for a probe function. 2057# 2058config TRACEPOINTS 2059 bool 2060 select TASKS_TRACE_RCU 2061 2062source "kernel/Kconfig.kexec" 2063 2064endmenu # General setup 2065 2066source "arch/Kconfig" 2067 2068config RT_MUTEXES 2069 bool 2070 default y if PREEMPT_RT 2071 2072config MODULE_SIG_FORMAT 2073 def_bool n 2074 select SYSTEM_DATA_VERIFICATION 2075 2076source "kernel/module/Kconfig" 2077 2078config INIT_ALL_POSSIBLE 2079 bool 2080 help 2081 Back when each arch used to define their own cpu_online_mask and 2082 cpu_possible_mask, some of them chose to initialize cpu_possible_mask 2083 with all 1s, and others with all 0s. When they were centralised, 2084 it was better to provide this option than to break all the archs 2085 and have several arch maintainers pursuing me down dark alleys. 2086 2087source "block/Kconfig" 2088 2089config PREEMPT_NOTIFIERS 2090 bool 2091 2092config PADATA 2093 depends on SMP 2094 bool 2095 2096config ASN1 2097 tristate 2098 help 2099 Build a simple ASN.1 grammar compiler that produces a bytecode output 2100 that can be interpreted by the ASN.1 stream decoder and used to 2101 inform it as to what tags are to be expected in a stream and what 2102 functions to call on what tags. 2103 2104source "kernel/Kconfig.locks" 2105 2106config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 2107 bool 2108 2109config ARCH_HAS_PREPARE_SYNC_CORE_CMD 2110 bool 2111 2112config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2113 bool 2114 2115# It may be useful for an architecture to override the definitions of the 2116# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> 2117# and the COMPAT_ variants in <linux/compat.h>, in particular to use a 2118# different calling convention for syscalls. They can also override the 2119# macros for not-implemented syscalls in kernel/sys_ni.c and 2120# kernel/time/posix-stubs.c. All these overrides need to be available in 2121# <asm/syscall_wrapper.h>. 2122config ARCH_HAS_SYSCALL_WRAPPER 2123 def_bool n 2124