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