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 90config CC_CAN_LINK_STATIC 91 bool 92 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag) -static) if 64BIT 93 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m32-flag) -static) 94 95# Fixed in GCC 14, 13.3, 12.4 and 11.5 96# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113921 97config GCC_ASM_GOTO_OUTPUT_BROKEN 98 bool 99 depends on CC_IS_GCC 100 default y if GCC_VERSION < 110500 101 default y if GCC_VERSION >= 120000 && GCC_VERSION < 120400 102 default y if GCC_VERSION >= 130000 && GCC_VERSION < 130300 103 104config CC_HAS_ASM_GOTO_OUTPUT 105 def_bool y 106 depends on !GCC_ASM_GOTO_OUTPUT_BROKEN 107 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) 108 109config CC_HAS_ASM_GOTO_TIED_OUTPUT 110 depends on CC_HAS_ASM_GOTO_OUTPUT 111 # Detect buggy gcc and clang, fixed in gcc-11 clang-14. 112 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) 113 114config TOOLS_SUPPORT_RELR 115 def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh) 116 117config CC_HAS_ASM_INLINE 118 def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null) 119 120config CC_HAS_NO_PROFILE_FN_ATTR 121 def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror) 122 123config CC_HAS_COUNTED_BY 124 # TODO: when gcc 15 is released remove the build test and add 125 # a gcc version check 126 def_bool $(success,echo 'struct flex { int count; int array[] __attribute__((__counted_by__(count))); };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror) 127 # clang needs to be at least 19.1.3 to avoid __bdos miscalculations 128 # https://github.com/llvm/llvm-project/pull/110497 129 # https://github.com/llvm/llvm-project/pull/112636 130 depends on !(CC_IS_CLANG && CLANG_VERSION < 190103) 131 132config CC_HAS_MULTIDIMENSIONAL_NONSTRING 133 def_bool $(success,echo 'char tag[][4] __attribute__((__nonstring__)) = { };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror) 134 135config LD_CAN_USE_KEEP_IN_OVERLAY 136 # ld.lld prior to 21.0.0 did not support KEEP within an overlay description 137 # https://github.com/llvm/llvm-project/pull/130661 138 def_bool LD_IS_BFD || LLD_VERSION >= 210000 139 140config RUSTC_HAS_COERCE_POINTEE 141 def_bool RUSTC_VERSION >= 108400 142 143config RUSTC_HAS_UNNECESSARY_TRANSMUTES 144 def_bool RUSTC_VERSION >= 108800 145 146config PAHOLE_VERSION 147 int 148 default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE)) 149 150config CONSTRUCTORS 151 bool 152 153config IRQ_WORK 154 def_bool y if SMP 155 156config BUILDTIME_TABLE_SORT 157 bool 158 159config THREAD_INFO_IN_TASK 160 bool 161 help 162 Select this to move thread_info off the stack into task_struct. To 163 make this work, an arch will need to remove all thread_info fields 164 except flags and fix any runtime bugs. 165 166 One subtle change that will be needed is to use try_get_task_stack() 167 and put_task_stack() in save_thread_stack_tsk() and get_wchan(). 168 169menu "General setup" 170 171config BROKEN 172 bool 173 174config BROKEN_ON_SMP 175 bool 176 depends on BROKEN || !SMP 177 default y 178 179config INIT_ENV_ARG_LIMIT 180 int 181 default 32 if !UML 182 default 128 if UML 183 help 184 Maximum of each of the number of arguments and environment 185 variables passed to init from the kernel command line. 186 187config COMPILE_TEST 188 bool "Compile also drivers which will not load" 189 depends on HAS_IOMEM 190 help 191 Some drivers can be compiled on a different platform than they are 192 intended to be run on. Despite they cannot be loaded there (or even 193 when they load they cannot be used due to missing HW support), 194 developers still, opposing to distributors, might want to build such 195 drivers to compile-test them. 196 197 If you are a developer and want to build everything available, say Y 198 here. If you are a user/distributor, say N here to exclude useless 199 drivers to be distributed. 200 201config WERROR 202 bool "Compile the kernel with warnings as errors" 203 default COMPILE_TEST 204 help 205 A kernel build should not cause any compiler warnings, and this 206 enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags 207 to enforce that rule by default. Certain warnings from other tools 208 such as the linker may be upgraded to errors with this option as 209 well. 210 211 However, if you have a new (or very old) compiler or linker with odd 212 and unusual warnings, or you have some architecture with problems, 213 you may need to disable this config option in order to 214 successfully build the kernel. 215 216 If in doubt, say Y. 217 218config UAPI_HEADER_TEST 219 bool "Compile test UAPI headers" 220 depends on HEADERS_INSTALL && CC_CAN_LINK 221 help 222 Compile test headers exported to user-space to ensure they are 223 self-contained, i.e. compilable as standalone units. 224 225 If you are a developer or tester and want to ensure the exported 226 headers are self-contained, say Y here. Otherwise, choose N. 227 228config LOCALVERSION 229 string "Local version - append to kernel release" 230 help 231 Append an extra string to the end of your kernel version. 232 This will show up when you type uname, for example. 233 The string you set here will be appended after the contents of 234 any files with a filename matching localversion* in your 235 object and source tree, in that order. Your total string can 236 be a maximum of 64 characters. 237 238config LOCALVERSION_AUTO 239 bool "Automatically append version information to the version string" 240 default y 241 depends on !COMPILE_TEST 242 help 243 This will try to automatically determine if the current tree is a 244 release tree by looking for git tags that belong to the current 245 top of tree revision. 246 247 A string of the format -gxxxxxxxx will be added to the localversion 248 if a git-based tree is found. The string generated by this will be 249 appended after any matching localversion* files, and after the value 250 set in CONFIG_LOCALVERSION. 251 252 (The actual string used here is the first 12 characters produced 253 by running the command: 254 255 $ git rev-parse --verify HEAD 256 257 which is done within the script "scripts/setlocalversion".) 258 259config BUILD_SALT 260 string "Build ID Salt" 261 default "" 262 help 263 The build ID is used to link binaries and their debug info. Setting 264 this option will use the value in the calculation of the build id. 265 This is mostly useful for distributions which want to ensure the 266 build is unique between builds. It's safe to leave the default. 267 268config HAVE_KERNEL_GZIP 269 bool 270 271config HAVE_KERNEL_BZIP2 272 bool 273 274config HAVE_KERNEL_LZMA 275 bool 276 277config HAVE_KERNEL_XZ 278 bool 279 280config HAVE_KERNEL_LZO 281 bool 282 283config HAVE_KERNEL_LZ4 284 bool 285 286config HAVE_KERNEL_ZSTD 287 bool 288 289config HAVE_KERNEL_UNCOMPRESSED 290 bool 291 292choice 293 prompt "Kernel compression mode" 294 default KERNEL_GZIP 295 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 296 help 297 The linux kernel is a kind of self-extracting executable. 298 Several compression algorithms are available, which differ 299 in efficiency, compression and decompression speed. 300 Compression speed is only relevant when building a kernel. 301 Decompression speed is relevant at each boot. 302 303 If you have any problems with bzip2 or lzma compressed 304 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 305 version of this functionality (bzip2 only), for 2.4, was 306 supplied by Christian Ludwig) 307 308 High compression options are mostly useful for users, who 309 are low on disk space (embedded systems), but for whom ram 310 size matters less. 311 312 If in doubt, select 'gzip' 313 314config KERNEL_GZIP 315 bool "Gzip" 316 depends on HAVE_KERNEL_GZIP 317 help 318 The old and tried gzip compression. It provides a good balance 319 between compression ratio and decompression speed. 320 321config KERNEL_BZIP2 322 bool "Bzip2" 323 depends on HAVE_KERNEL_BZIP2 324 help 325 Its compression ratio and speed is intermediate. 326 Decompression speed is slowest among the choices. The kernel 327 size is about 10% smaller with bzip2, in comparison to gzip. 328 Bzip2 uses a large amount of memory. For modern kernels you 329 will need at least 8MB RAM or more for booting. 330 331config KERNEL_LZMA 332 bool "LZMA" 333 depends on HAVE_KERNEL_LZMA 334 help 335 This compression algorithm's ratio is best. Decompression speed 336 is between gzip and bzip2. Compression is slowest. 337 The kernel size is about 33% smaller with LZMA in comparison to gzip. 338 339config KERNEL_XZ 340 bool "XZ" 341 depends on HAVE_KERNEL_XZ 342 help 343 XZ uses the LZMA2 algorithm and instruction set specific 344 BCJ filters which can improve compression ratio of executable 345 code. The size of the kernel is about 30% smaller with XZ in 346 comparison to gzip. On architectures for which there is a BCJ 347 filter (i386, x86_64, ARM, ARM64, RISC-V, big endian PowerPC, 348 and SPARC), XZ will create a few percent smaller kernel than 349 plain LZMA. 350 351 The speed is about the same as with LZMA: The decompression 352 speed of XZ is better than that of bzip2 but worse than gzip 353 and LZO. Compression is slow. 354 355config KERNEL_LZO 356 bool "LZO" 357 depends on HAVE_KERNEL_LZO 358 help 359 Its compression ratio is the poorest among the choices. The kernel 360 size is about 10% bigger than gzip; however its speed 361 (both compression and decompression) is the fastest. 362 363config KERNEL_LZ4 364 bool "LZ4" 365 depends on HAVE_KERNEL_LZ4 366 help 367 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. 368 A preliminary version of LZ4 de/compression tool is available at 369 <https://code.google.com/p/lz4/>. 370 371 Its compression ratio is worse than LZO. The size of the kernel 372 is about 8% bigger than LZO. But the decompression speed is 373 faster than LZO. 374 375config KERNEL_ZSTD 376 bool "ZSTD" 377 depends on HAVE_KERNEL_ZSTD 378 help 379 ZSTD is a compression algorithm targeting intermediate compression 380 with fast decompression speed. It will compress better than GZIP and 381 decompress around the same speed as LZO, but slower than LZ4. You 382 will need at least 192 KB RAM or more for booting. The zstd command 383 line tool is required for compression. 384 385config KERNEL_UNCOMPRESSED 386 bool "None" 387 depends on HAVE_KERNEL_UNCOMPRESSED 388 help 389 Produce uncompressed kernel image. This option is usually not what 390 you want. It is useful for debugging the kernel in slow simulation 391 environments, where decompressing and moving the kernel is awfully 392 slow. This option allows early boot code to skip the decompressor 393 and jump right at uncompressed kernel image. 394 395endchoice 396 397config DEFAULT_INIT 398 string "Default init path" 399 default "" 400 help 401 This option determines the default init for the system if no init= 402 option is passed on the kernel command line. If the requested path is 403 not present, we will still then move on to attempting further 404 locations (e.g. /sbin/init, etc). If this is empty, we will just use 405 the fallback list when init= is not passed. 406 407config DEFAULT_HOSTNAME 408 string "Default hostname" 409 default "(none)" 410 help 411 This option determines the default system hostname before userspace 412 calls sethostname(2). The kernel traditionally uses "(none)" here, 413 but you may wish to use a different default here to make a minimal 414 system more usable with less configuration. 415 416config SYSVIPC 417 bool "System V IPC" 418 help 419 Inter Process Communication is a suite of library functions and 420 system calls which let processes (running programs) synchronize and 421 exchange information. It is generally considered to be a good thing, 422 and some programs won't run unless you say Y here. In particular, if 423 you want to run the DOS emulator dosemu under Linux (read the 424 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 425 you'll need to say Y here. 426 427 You can find documentation about IPC with "info ipc" and also in 428 section 6.4 of the Linux Programmer's Guide, available from 429 <http://www.tldp.org/guides.html>. 430 431config SYSVIPC_SYSCTL 432 bool 433 depends on SYSVIPC 434 depends on SYSCTL 435 default y 436 437config SYSVIPC_COMPAT 438 def_bool y 439 depends on COMPAT && SYSVIPC 440 441config POSIX_MQUEUE 442 bool "POSIX Message Queues" 443 depends on NET 444 help 445 POSIX variant of message queues is a part of IPC. In POSIX message 446 queues every message has a priority which decides about succession 447 of receiving it by a process. If you want to compile and run 448 programs written e.g. for Solaris with use of its POSIX message 449 queues (functions mq_*) say Y here. 450 451 POSIX message queues are visible as a filesystem called 'mqueue' 452 and can be mounted somewhere if you want to do filesystem 453 operations on message queues. 454 455 If unsure, say Y. 456 457config POSIX_MQUEUE_SYSCTL 458 bool 459 depends on POSIX_MQUEUE 460 depends on SYSCTL 461 default y 462 463config WATCH_QUEUE 464 bool "General notification queue" 465 default n 466 help 467 468 This is a general notification queue for the kernel to pass events to 469 userspace by splicing them into pipes. It can be used in conjunction 470 with watches for key/keyring change notifications and device 471 notifications. 472 473 See Documentation/core-api/watch_queue.rst 474 475config CROSS_MEMORY_ATTACH 476 bool "Enable process_vm_readv/writev syscalls" 477 depends on MMU 478 default y 479 help 480 Enabling this option adds the system calls process_vm_readv and 481 process_vm_writev which allow a process with the correct privileges 482 to directly read from or write to another process' address space. 483 See the man page for more details. 484 485config USELIB 486 bool "uselib syscall (for libc5 and earlier)" 487 default ALPHA || M68K || SPARC 488 help 489 This option enables the uselib syscall, a system call used in the 490 dynamic linker from libc5 and earlier. glibc does not use this 491 system call. If you intend to run programs built on libc5 or 492 earlier, you may need to enable this syscall. Current systems 493 running glibc can safely disable this. 494 495config AUDIT 496 bool "Auditing support" 497 depends on NET 498 help 499 Enable auditing infrastructure that can be used with another 500 kernel subsystem, such as SELinux (which requires this for 501 logging of avc messages output). System call auditing is included 502 on architectures which support it. 503 504config HAVE_ARCH_AUDITSYSCALL 505 bool 506 507config AUDITSYSCALL 508 def_bool y 509 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL 510 select FSNOTIFY 511 512source "kernel/irq/Kconfig" 513source "kernel/time/Kconfig" 514source "kernel/bpf/Kconfig" 515source "kernel/Kconfig.preempt" 516 517menu "CPU/Task time and stats accounting" 518 519config VIRT_CPU_ACCOUNTING 520 bool 521 522choice 523 prompt "Cputime accounting" 524 default TICK_CPU_ACCOUNTING 525 526# Kind of a stub config for the pure tick based cputime accounting 527config TICK_CPU_ACCOUNTING 528 bool "Simple tick based cputime accounting" 529 depends on !S390 && !NO_HZ_FULL 530 help 531 This is the basic tick based cputime accounting that maintains 532 statistics about user, system and idle time spent on per jiffies 533 granularity. 534 535 If unsure, say Y. 536 537config VIRT_CPU_ACCOUNTING_NATIVE 538 bool "Deterministic task and CPU time accounting" 539 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL 540 select VIRT_CPU_ACCOUNTING 541 help 542 Select this option to enable more accurate task and CPU time 543 accounting. This is done by reading a CPU counter on each 544 kernel entry and exit and on transitions within the kernel 545 between system, softirq and hardirq state, so there is a 546 small performance impact. In the case of s390 or IBM POWER > 5, 547 this also enables accounting of stolen time on logically-partitioned 548 systems. 549 550config VIRT_CPU_ACCOUNTING_GEN 551 bool "Full dynticks CPU time accounting" 552 depends on HAVE_CONTEXT_TRACKING_USER 553 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN 554 depends on GENERIC_CLOCKEVENTS 555 select VIRT_CPU_ACCOUNTING 556 select CONTEXT_TRACKING_USER 557 help 558 Select this option to enable task and CPU time accounting on full 559 dynticks systems. This accounting is implemented by watching every 560 kernel-user boundaries using the context tracking subsystem. 561 The accounting is thus performed at the expense of some significant 562 overhead. 563 564 For now this is only useful if you are working on the full 565 dynticks subsystem development. 566 567 If unsure, say N. 568 569endchoice 570 571config IRQ_TIME_ACCOUNTING 572 bool "Fine granularity task level IRQ time accounting" 573 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE 574 help 575 Select this option to enable fine granularity task irq time 576 accounting. This is done by reading a timestamp on each 577 transitions between softirq and hardirq state, so there can be a 578 small performance impact. 579 580 If in doubt, say N here. 581 582config HAVE_SCHED_AVG_IRQ 583 def_bool y 584 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING 585 depends on SMP 586 587config SCHED_HW_PRESSURE 588 bool 589 default y if ARM && ARM_CPU_TOPOLOGY 590 default y if ARM64 591 depends on SMP 592 depends on CPU_FREQ_THERMAL 593 help 594 Select this option to enable HW pressure accounting in the 595 scheduler. HW pressure is the value conveyed to the scheduler 596 that reflects the reduction in CPU compute capacity resulted from 597 HW throttling. HW throttling occurs when the performance of 598 a CPU is capped due to high operating temperatures as an example. 599 600 If selected, the scheduler will be able to balance tasks accordingly, 601 i.e. put less load on throttled CPUs than on non/less throttled ones. 602 603 This requires the architecture to implement 604 arch_update_hw_pressure() and arch_scale_thermal_pressure(). 605 606config BSD_PROCESS_ACCT 607 bool "BSD Process Accounting" 608 depends on MULTIUSER 609 help 610 If you say Y here, a user level program will be able to instruct the 611 kernel (via a special system call) to write process accounting 612 information to a file: whenever a process exits, information about 613 that process will be appended to the file by the kernel. The 614 information includes things such as creation time, owning user, 615 command name, memory usage, controlling terminal etc. (the complete 616 list is in the struct acct in <file:include/linux/acct.h>). It is 617 up to the user level program to do useful things with this 618 information. This is generally a good idea, so say Y. 619 620config BSD_PROCESS_ACCT_V3 621 bool "BSD Process Accounting version 3 file format" 622 depends on BSD_PROCESS_ACCT 623 default n 624 help 625 If you say Y here, the process accounting information is written 626 in a new file format that also logs the process IDs of each 627 process and its parent. Note that this file format is incompatible 628 with previous v0/v1/v2 file formats, so you will need updated tools 629 for processing it. A preliminary version of these tools is available 630 at <http://www.gnu.org/software/acct/>. 631 632config TASKSTATS 633 bool "Export task/process statistics through netlink" 634 depends on NET 635 depends on MULTIUSER 636 default n 637 help 638 Export selected statistics for tasks/processes through the 639 generic netlink interface. Unlike BSD process accounting, the 640 statistics are available during the lifetime of tasks/processes as 641 responses to commands. Like BSD accounting, they are sent to user 642 space on task exit. 643 644 Say N if unsure. 645 646config TASK_DELAY_ACCT 647 bool "Enable per-task delay accounting" 648 depends on TASKSTATS 649 select SCHED_INFO 650 help 651 Collect information on time spent by a task waiting for system 652 resources like cpu, synchronous block I/O completion and swapping 653 in pages. Such statistics can help in setting a task's priorities 654 relative to other tasks for cpu, io, rss limits etc. 655 656 Say N if unsure. 657 658config TASK_XACCT 659 bool "Enable extended accounting over taskstats" 660 depends on TASKSTATS 661 help 662 Collect extended task accounting data and send the data 663 to userland for processing over the taskstats interface. 664 665 Say N if unsure. 666 667config TASK_IO_ACCOUNTING 668 bool "Enable per-task storage I/O accounting" 669 depends on TASK_XACCT 670 help 671 Collect information on the number of bytes of storage I/O which this 672 task has caused. 673 674 Say N if unsure. 675 676config PSI 677 bool "Pressure stall information tracking" 678 select KERNFS 679 help 680 Collect metrics that indicate how overcommitted the CPU, memory, 681 and IO capacity are in the system. 682 683 If you say Y here, the kernel will create /proc/pressure/ with the 684 pressure statistics files cpu, memory, and io. These will indicate 685 the share of walltime in which some or all tasks in the system are 686 delayed due to contention of the respective resource. 687 688 In kernels with cgroup support, cgroups (cgroup2 only) will 689 have cpu.pressure, memory.pressure, and io.pressure files, 690 which aggregate pressure stalls for the grouped tasks only. 691 692 For more details see Documentation/accounting/psi.rst. 693 694 Say N if unsure. 695 696config PSI_DEFAULT_DISABLED 697 bool "Require boot parameter to enable pressure stall information tracking" 698 default n 699 depends on PSI 700 help 701 If set, pressure stall information tracking will be disabled 702 per default but can be enabled through passing psi=1 on the 703 kernel commandline during boot. 704 705 This feature adds some code to the task wakeup and sleep 706 paths of the scheduler. The overhead is too low to affect 707 common scheduling-intense workloads in practice (such as 708 webservers, memcache), but it does show up in artificial 709 scheduler stress tests, such as hackbench. 710 711 If you are paranoid and not sure what the kernel will be 712 used for, say Y. 713 714 Say N if unsure. 715 716endmenu # "CPU/Task time and stats accounting" 717 718config CPU_ISOLATION 719 bool "CPU isolation" 720 depends on SMP 721 default y 722 help 723 Make sure that CPUs running critical tasks are not disturbed by 724 any source of "noise" such as unbound workqueues, timers, kthreads... 725 Unbound jobs get offloaded to housekeeping CPUs. This is driven by 726 the "isolcpus=" boot parameter. 727 728 Say Y if unsure. 729 730source "kernel/rcu/Kconfig" 731 732config IKCONFIG 733 tristate "Kernel .config support" 734 help 735 This option enables the complete Linux kernel ".config" file 736 contents to be saved in the kernel. It provides documentation 737 of which kernel options are used in a running kernel or in an 738 on-disk kernel. This information can be extracted from the kernel 739 image file with the script scripts/extract-ikconfig and used as 740 input to rebuild the current kernel or to build another kernel. 741 It can also be extracted from a running kernel by reading 742 /proc/config.gz if enabled (below). 743 744config IKCONFIG_PROC 745 bool "Enable access to .config through /proc/config.gz" 746 depends on IKCONFIG && PROC_FS 747 help 748 This option enables access to the kernel configuration file 749 through /proc/config.gz. 750 751config IKHEADERS 752 tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz" 753 depends on SYSFS 754 help 755 This option enables access to the in-kernel headers that are generated during 756 the build process. These can be used to build eBPF tracing programs, 757 or similar programs. If you build the headers as a module, a module called 758 kheaders.ko is built which can be loaded on-demand to get access to headers. 759 760config LOG_BUF_SHIFT 761 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 762 range 12 25 763 default 17 764 depends on PRINTK 765 help 766 Select the minimal kernel log buffer size as a power of 2. 767 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config 768 parameter, see below. Any higher size also might be forced 769 by "log_buf_len" boot parameter. 770 771 Examples: 772 17 => 128 KB 773 16 => 64 KB 774 15 => 32 KB 775 14 => 16 KB 776 13 => 8 KB 777 12 => 4 KB 778 779config LOG_CPU_MAX_BUF_SHIFT 780 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" 781 depends on SMP 782 range 0 21 783 default 0 if BASE_SMALL 784 default 12 785 depends on PRINTK 786 help 787 This option allows to increase the default ring buffer size 788 according to the number of CPUs. The value defines the contribution 789 of each CPU as a power of 2. The used space is typically only few 790 lines however it might be much more when problems are reported, 791 e.g. backtraces. 792 793 The increased size means that a new buffer has to be allocated and 794 the original static one is unused. It makes sense only on systems 795 with more CPUs. Therefore this value is used only when the sum of 796 contributions is greater than the half of the default kernel ring 797 buffer as defined by LOG_BUF_SHIFT. The default values are set 798 so that more than 16 CPUs are needed to trigger the allocation. 799 800 Also this option is ignored when "log_buf_len" kernel parameter is 801 used as it forces an exact (power of two) size of the ring buffer. 802 803 The number of possible CPUs is used for this computation ignoring 804 hotplugging making the computation optimal for the worst case 805 scenario while allowing a simple algorithm to be used from bootup. 806 807 Examples shift values and their meaning: 808 17 => 128 KB for each CPU 809 16 => 64 KB for each CPU 810 15 => 32 KB for each CPU 811 14 => 16 KB for each CPU 812 13 => 8 KB for each CPU 813 12 => 4 KB for each CPU 814 815config PRINTK_INDEX 816 bool "Printk indexing debugfs interface" 817 depends on PRINTK && DEBUG_FS 818 help 819 Add support for indexing of all printk formats known at compile time 820 at <debugfs>/printk/index/<module>. 821 822 This can be used as part of maintaining daemons which monitor 823 /dev/kmsg, as it permits auditing the printk formats present in a 824 kernel, allowing detection of cases where monitored printks are 825 changed or no longer present. 826 827 There is no additional runtime cost to printk with this enabled. 828 829# 830# Architectures with an unreliable sched_clock() should select this: 831# 832config HAVE_UNSTABLE_SCHED_CLOCK 833 bool 834 835config GENERIC_SCHED_CLOCK 836 bool 837 838menu "Scheduler features" 839 840config UCLAMP_TASK 841 bool "Enable utilization clamping for RT/FAIR tasks" 842 depends on CPU_FREQ_GOV_SCHEDUTIL 843 help 844 This feature enables the scheduler to track the clamped utilization 845 of each CPU based on RUNNABLE tasks scheduled on that CPU. 846 847 With this option, the user can specify the min and max CPU 848 utilization allowed for RUNNABLE tasks. The max utilization defines 849 the maximum frequency a task should use while the min utilization 850 defines the minimum frequency it should use. 851 852 Both min and max utilization clamp values are hints to the scheduler, 853 aiming at improving its frequency selection policy, but they do not 854 enforce or grant any specific bandwidth for tasks. 855 856 If in doubt, say N. 857 858config UCLAMP_BUCKETS_COUNT 859 int "Number of supported utilization clamp buckets" 860 range 5 20 861 default 5 862 depends on UCLAMP_TASK 863 help 864 Defines the number of clamp buckets to use. The range of each bucket 865 will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the 866 number of clamp buckets the finer their granularity and the higher 867 the precision of clamping aggregation and tracking at run-time. 868 869 For example, with the minimum configuration value we will have 5 870 clamp buckets tracking 20% utilization each. A 25% boosted tasks will 871 be refcounted in the [20..39]% bucket and will set the bucket clamp 872 effective value to 25%. 873 If a second 30% boosted task should be co-scheduled on the same CPU, 874 that task will be refcounted in the same bucket of the first task and 875 it will boost the bucket clamp effective value to 30%. 876 The clamp effective value of a bucket is reset to its nominal value 877 (20% in the example above) when there are no more tasks refcounted in 878 that bucket. 879 880 An additional boost/capping margin can be added to some tasks. In the 881 example above the 25% task will be boosted to 30% until it exits the 882 CPU. If that should be considered not acceptable on certain systems, 883 it's always possible to reduce the margin by increasing the number of 884 clamp buckets to trade off used memory for run-time tracking 885 precision. 886 887 If in doubt, use the default value. 888 889endmenu 890 891# 892# For architectures that want to enable the support for NUMA-affine scheduler 893# balancing logic: 894# 895config ARCH_SUPPORTS_NUMA_BALANCING 896 bool 897 898# 899# For architectures that prefer to flush all TLBs after a number of pages 900# are unmapped instead of sending one IPI per page to flush. The architecture 901# must provide guarantees on what happens if a clean TLB cache entry is 902# written after the unmap. Details are in mm/rmap.c near the check for 903# should_defer_flush. The architecture should also consider if the full flush 904# and the refill costs are offset by the savings of sending fewer IPIs. 905config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 906 bool 907 908config CC_HAS_INT128 909 def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT 910 911config CC_IMPLICIT_FALLTHROUGH 912 string 913 default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) 914 default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) 915 916# Currently, disable gcc-10+ array-bounds globally. 917# It's still broken in gcc-13, so no upper bound yet. 918config GCC10_NO_ARRAY_BOUNDS 919 def_bool y 920 921config CC_NO_ARRAY_BOUNDS 922 bool 923 default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC10_NO_ARRAY_BOUNDS 924 925# Currently, disable -Wstringop-overflow for GCC globally. 926config GCC_NO_STRINGOP_OVERFLOW 927 def_bool y 928 929config CC_NO_STRINGOP_OVERFLOW 930 bool 931 default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW 932 933config CC_STRINGOP_OVERFLOW 934 bool 935 default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW 936 937# 938# For architectures that know their GCC __int128 support is sound 939# 940config ARCH_SUPPORTS_INT128 941 bool 942 943# For architectures that (ab)use NUMA to represent different memory regions 944# all cpu-local but of different latencies, such as SuperH. 945# 946config ARCH_WANT_NUMA_VARIABLE_LOCALITY 947 bool 948 949config NUMA_BALANCING 950 bool "Memory placement aware NUMA scheduler" 951 depends on ARCH_SUPPORTS_NUMA_BALANCING 952 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY 953 depends on SMP && NUMA && MIGRATION && !PREEMPT_RT 954 help 955 This option adds support for automatic NUMA aware memory/task placement. 956 The mechanism is quite primitive and is based on migrating memory when 957 it has references to the node the task is running on. 958 959 This system will be inactive on UMA systems. 960 961config NUMA_BALANCING_DEFAULT_ENABLED 962 bool "Automatically enable NUMA aware memory/task placement" 963 default y 964 depends on NUMA_BALANCING 965 help 966 If set, automatic NUMA balancing will be enabled if running on a NUMA 967 machine. 968 969config SLAB_OBJ_EXT 970 bool 971 972menuconfig CGROUPS 973 bool "Control Group support" 974 select KERNFS 975 help 976 This option adds support for grouping sets of processes together, for 977 use with process control subsystems such as Cpusets, CFS, memory 978 controls or device isolation. 979 See 980 - Documentation/scheduler/sched-design-CFS.rst (CFS) 981 - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation 982 and resource control) 983 984 Say N if unsure. 985 986if CGROUPS 987 988config PAGE_COUNTER 989 bool 990 991config CGROUP_FAVOR_DYNMODS 992 bool "Favor dynamic modification latency reduction by default" 993 help 994 This option enables the "favordynmods" mount option by default 995 which reduces the latencies of dynamic cgroup modifications such 996 as task migrations and controller on/offs at the cost of making 997 hot path operations such as forks and exits more expensive. 998 999 Say N if unsure. 1000 1001config MEMCG 1002 bool "Memory controller" 1003 select PAGE_COUNTER 1004 select EVENTFD 1005 select SLAB_OBJ_EXT 1006 help 1007 Provides control over the memory footprint of tasks in a cgroup. 1008 1009config MEMCG_V1 1010 bool "Legacy cgroup v1 memory controller" 1011 depends on MEMCG 1012 default n 1013 help 1014 Legacy cgroup v1 memory controller which has been deprecated by 1015 cgroup v2 implementation. The v1 is there for legacy applications 1016 which haven't migrated to the new cgroup v2 interface yet. If you 1017 do not have any such application then you are completely fine leaving 1018 this option disabled. 1019 1020 Please note that feature set of the legacy memory controller is likely 1021 going to shrink due to deprecation process. New deployments with v1 1022 controller are highly discouraged. 1023 1024 Say N if unsure. 1025 1026config BLK_CGROUP 1027 bool "IO controller" 1028 depends on BLOCK 1029 default n 1030 help 1031 Generic block IO controller cgroup interface. This is the common 1032 cgroup interface which should be used by various IO controlling 1033 policies. 1034 1035 Currently, CFQ IO scheduler uses it to recognize task groups and 1036 control disk bandwidth allocation (proportional time slice allocation) 1037 to such task groups. It is also used by bio throttling logic in 1038 block layer to implement upper limit in IO rates on a device. 1039 1040 This option only enables generic Block IO controller infrastructure. 1041 One needs to also enable actual IO controlling logic/policy. For 1042 enabling proportional weight division of disk bandwidth in CFQ, set 1043 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 1044 CONFIG_BLK_DEV_THROTTLING=y. 1045 1046 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information. 1047 1048config CGROUP_WRITEBACK 1049 bool 1050 depends on MEMCG && BLK_CGROUP 1051 default y 1052 1053menuconfig CGROUP_SCHED 1054 bool "CPU controller" 1055 default n 1056 help 1057 This feature lets CPU scheduler recognize task groups and control CPU 1058 bandwidth allocation to such task groups. It uses cgroups to group 1059 tasks. 1060 1061if CGROUP_SCHED 1062config GROUP_SCHED_WEIGHT 1063 def_bool n 1064 1065config FAIR_GROUP_SCHED 1066 bool "Group scheduling for SCHED_OTHER" 1067 depends on CGROUP_SCHED 1068 select GROUP_SCHED_WEIGHT 1069 default CGROUP_SCHED 1070 1071config CFS_BANDWIDTH 1072 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 1073 depends on FAIR_GROUP_SCHED 1074 default n 1075 help 1076 This option allows users to define CPU bandwidth rates (limits) for 1077 tasks running within the fair group scheduler. Groups with no limit 1078 set are considered to be unconstrained and will run with no 1079 restriction. 1080 See Documentation/scheduler/sched-bwc.rst for more information. 1081 1082config RT_GROUP_SCHED 1083 bool "Group scheduling for SCHED_RR/FIFO" 1084 depends on CGROUP_SCHED 1085 default n 1086 help 1087 This feature lets you explicitly allocate real CPU bandwidth 1088 to task groups. If enabled, it will also make it impossible to 1089 schedule realtime tasks for non-root users until you allocate 1090 realtime bandwidth for them. 1091 See Documentation/scheduler/sched-rt-group.rst for more information. 1092 1093config EXT_GROUP_SCHED 1094 bool 1095 depends on SCHED_CLASS_EXT && CGROUP_SCHED 1096 select GROUP_SCHED_WEIGHT 1097 default y 1098 1099endif #CGROUP_SCHED 1100 1101config SCHED_MM_CID 1102 def_bool y 1103 depends on SMP && RSEQ 1104 1105config UCLAMP_TASK_GROUP 1106 bool "Utilization clamping per group of tasks" 1107 depends on CGROUP_SCHED 1108 depends on UCLAMP_TASK 1109 default n 1110 help 1111 This feature enables the scheduler to track the clamped utilization 1112 of each CPU based on RUNNABLE tasks currently scheduled on that CPU. 1113 1114 When this option is enabled, the user can specify a min and max 1115 CPU bandwidth which is allowed for each single task in a group. 1116 The max bandwidth allows to clamp the maximum frequency a task 1117 can use, while the min bandwidth allows to define a minimum 1118 frequency a task will always use. 1119 1120 When task group based utilization clamping is enabled, an eventually 1121 specified task-specific clamp value is constrained by the cgroup 1122 specified clamp value. Both minimum and maximum task clamping cannot 1123 be bigger than the corresponding clamping defined at task group level. 1124 1125 If in doubt, say N. 1126 1127config CGROUP_PIDS 1128 bool "PIDs controller" 1129 help 1130 Provides enforcement of process number limits in the scope of a 1131 cgroup. Any attempt to fork more processes than is allowed in the 1132 cgroup will fail. PIDs are fundamentally a global resource because it 1133 is fairly trivial to reach PID exhaustion before you reach even a 1134 conservative kmemcg limit. As a result, it is possible to grind a 1135 system to halt without being limited by other cgroup policies. The 1136 PIDs controller is designed to stop this from happening. 1137 1138 It should be noted that organisational operations (such as attaching 1139 to a cgroup hierarchy) will *not* be blocked by the PIDs controller, 1140 since the PIDs limit only affects a process's ability to fork, not to 1141 attach to a cgroup. 1142 1143config CGROUP_RDMA 1144 bool "RDMA controller" 1145 help 1146 Provides enforcement of RDMA resources defined by IB stack. 1147 It is fairly easy for consumers to exhaust RDMA resources, which 1148 can result into resource unavailability to other consumers. 1149 RDMA controller is designed to stop this from happening. 1150 Attaching processes with active RDMA resources to the cgroup 1151 hierarchy is allowed even if can cross the hierarchy's limit. 1152 1153config CGROUP_DMEM 1154 bool "Device memory controller (DMEM)" 1155 select PAGE_COUNTER 1156 help 1157 The DMEM controller allows compatible devices to restrict device 1158 memory usage based on the cgroup hierarchy. 1159 1160 As an example, it allows you to restrict VRAM usage for applications 1161 in the DRM subsystem. 1162 1163config CGROUP_FREEZER 1164 bool "Freezer controller" 1165 help 1166 Provides a way to freeze and unfreeze all tasks in a 1167 cgroup. 1168 1169 This option affects the ORIGINAL cgroup interface. The cgroup2 memory 1170 controller includes important in-kernel memory consumers per default. 1171 1172 If you're using cgroup2, say N. 1173 1174config CGROUP_HUGETLB 1175 bool "HugeTLB controller" 1176 depends on HUGETLB_PAGE 1177 select PAGE_COUNTER 1178 default n 1179 help 1180 Provides a cgroup controller for HugeTLB pages. 1181 When you enable this, you can put a per cgroup limit on HugeTLB usage. 1182 The limit is enforced during page fault. Since HugeTLB doesn't 1183 support page reclaim, enforcing the limit at page fault time implies 1184 that, the application will get SIGBUS signal if it tries to access 1185 HugeTLB pages beyond its limit. This requires the application to know 1186 beforehand how much HugeTLB pages it would require for its use. The 1187 control group is tracked in the third page lru pointer. This means 1188 that we cannot use the controller with huge page less than 3 pages. 1189 1190config CPUSETS 1191 bool "Cpuset controller" 1192 depends on SMP 1193 select UNION_FIND 1194 help 1195 This option will let you create and manage CPUSETs which 1196 allow dynamically partitioning a system into sets of CPUs and 1197 Memory Nodes and assigning tasks to run only within those sets. 1198 This is primarily useful on large SMP or NUMA systems. 1199 1200 Say N if unsure. 1201 1202config CPUSETS_V1 1203 bool "Legacy cgroup v1 cpusets controller" 1204 depends on CPUSETS 1205 default n 1206 help 1207 Legacy cgroup v1 cpusets controller which has been deprecated by 1208 cgroup v2 implementation. The v1 is there for legacy applications 1209 which haven't migrated to the new cgroup v2 interface yet. Legacy 1210 interface includes cpuset filesystem and /proc/<pid>/cpuset. If you 1211 do not have any such application then you are completely fine leaving 1212 this option disabled. 1213 1214 Say N if unsure. 1215 1216config PROC_PID_CPUSET 1217 bool "Include legacy /proc/<pid>/cpuset file" 1218 depends on CPUSETS_V1 1219 default y 1220 1221config CGROUP_DEVICE 1222 bool "Device controller" 1223 help 1224 Provides a cgroup controller implementing whitelists for 1225 devices which a process in the cgroup can mknod or open. 1226 1227config CGROUP_CPUACCT 1228 bool "Simple CPU accounting controller" 1229 help 1230 Provides a simple controller for monitoring the 1231 total CPU consumed by the tasks in a cgroup. 1232 1233config CGROUP_PERF 1234 bool "Perf controller" 1235 depends on PERF_EVENTS 1236 help 1237 This option extends the perf per-cpu mode to restrict monitoring 1238 to threads which belong to the cgroup specified and run on the 1239 designated cpu. Or this can be used to have cgroup ID in samples 1240 so that it can monitor performance events among cgroups. 1241 1242 Say N if unsure. 1243 1244config CGROUP_BPF 1245 bool "Support for eBPF programs attached to cgroups" 1246 depends on BPF_SYSCALL 1247 select SOCK_CGROUP_DATA 1248 help 1249 Allow attaching eBPF programs to a cgroup using the bpf(2) 1250 syscall command BPF_PROG_ATTACH. 1251 1252 In which context these programs are accessed depends on the type 1253 of attachment. For instance, programs that are attached using 1254 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of 1255 inet sockets. 1256 1257config CGROUP_MISC 1258 bool "Misc resource controller" 1259 default n 1260 help 1261 Provides a controller for miscellaneous resources on a host. 1262 1263 Miscellaneous scalar resources are the resources on the host system 1264 which cannot be abstracted like the other cgroups. This controller 1265 tracks and limits the miscellaneous resources used by a process 1266 attached to a cgroup hierarchy. 1267 1268 For more information, please check misc cgroup section in 1269 /Documentation/admin-guide/cgroup-v2.rst. 1270 1271config CGROUP_DEBUG 1272 bool "Debug controller" 1273 default n 1274 depends on DEBUG_KERNEL 1275 help 1276 This option enables a simple controller that exports 1277 debugging information about the cgroups framework. This 1278 controller is for control cgroup debugging only. Its 1279 interfaces are not stable. 1280 1281 Say N. 1282 1283config SOCK_CGROUP_DATA 1284 bool 1285 default n 1286 1287endif # CGROUPS 1288 1289menuconfig NAMESPACES 1290 bool "Namespaces support" if EXPERT 1291 depends on MULTIUSER 1292 default !EXPERT 1293 help 1294 Provides the way to make tasks work with different objects using 1295 the same id. For example same IPC id may refer to different objects 1296 or same user id or pid may refer to different tasks when used in 1297 different namespaces. 1298 1299if NAMESPACES 1300 1301config UTS_NS 1302 bool "UTS namespace" 1303 default y 1304 help 1305 In this namespace tasks see different info provided with the 1306 uname() system call 1307 1308config TIME_NS 1309 bool "TIME namespace" 1310 depends on GENERIC_VDSO_TIME_NS 1311 default y 1312 help 1313 In this namespace boottime and monotonic clocks can be set. 1314 The time will keep going with the same pace. 1315 1316config IPC_NS 1317 bool "IPC namespace" 1318 depends on (SYSVIPC || POSIX_MQUEUE) 1319 default y 1320 help 1321 In this namespace tasks work with IPC ids which correspond to 1322 different IPC objects in different namespaces. 1323 1324config USER_NS 1325 bool "User namespace" 1326 default n 1327 help 1328 This allows containers, i.e. vservers, to use user namespaces 1329 to provide different user info for different servers. 1330 1331 When user namespaces are enabled in the kernel it is 1332 recommended that the MEMCG option also be enabled and that 1333 user-space use the memory control groups to limit the amount 1334 of memory a memory unprivileged users can use. 1335 1336 If unsure, say N. 1337 1338config PID_NS 1339 bool "PID Namespaces" 1340 default y 1341 help 1342 Support process id namespaces. This allows having multiple 1343 processes with the same pid as long as they are in different 1344 pid namespaces. This is a building block of containers. 1345 1346config NET_NS 1347 bool "Network namespace" 1348 depends on NET 1349 default y 1350 help 1351 Allow user space to create what appear to be multiple instances 1352 of the network stack. 1353 1354endif # NAMESPACES 1355 1356config CHECKPOINT_RESTORE 1357 bool "Checkpoint/restore support" 1358 depends on PROC_FS 1359 select PROC_CHILDREN 1360 select KCMP 1361 default n 1362 help 1363 Enables additional kernel features in a sake of checkpoint/restore. 1364 In particular it adds auxiliary prctl codes to setup process text, 1365 data and heap segment sizes, and a few additional /proc filesystem 1366 entries. 1367 1368 If unsure, say N here. 1369 1370config SCHED_AUTOGROUP 1371 bool "Automatic process group scheduling" 1372 select CGROUPS 1373 select CGROUP_SCHED 1374 select FAIR_GROUP_SCHED 1375 help 1376 This option optimizes the scheduler for common desktop workloads by 1377 automatically creating and populating task groups. This separation 1378 of workloads isolates aggressive CPU burners (like build jobs) from 1379 desktop applications. Task group autogeneration is currently based 1380 upon task session. 1381 1382config RELAY 1383 bool "Kernel->user space relay support (formerly relayfs)" 1384 select IRQ_WORK 1385 help 1386 This option enables support for relay interface support in 1387 certain file systems (such as debugfs). 1388 It is designed to provide an efficient mechanism for tools and 1389 facilities to relay large amounts of data from kernel space to 1390 user space. 1391 1392 If unsure, say N. 1393 1394config BLK_DEV_INITRD 1395 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1396 help 1397 The initial RAM filesystem is a ramfs which is loaded by the 1398 boot loader (loadlin or lilo) and that is mounted as root 1399 before the normal boot procedure. It is typically used to 1400 load modules needed to mount the "real" root file system, 1401 etc. See <file:Documentation/admin-guide/initrd.rst> for details. 1402 1403 If RAM disk support (BLK_DEV_RAM) is also included, this 1404 also enables initial RAM disk (initrd) support and adds 1405 15 Kbytes (more on some other architectures) to the kernel size. 1406 1407 If unsure say Y. 1408 1409if BLK_DEV_INITRD 1410 1411source "usr/Kconfig" 1412 1413endif 1414 1415config BOOT_CONFIG 1416 bool "Boot config support" 1417 select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED 1418 help 1419 Extra boot config allows system admin to pass a config file as 1420 complemental extension of kernel cmdline when booting. 1421 The boot config file must be attached at the end of initramfs 1422 with checksum, size and magic word. 1423 See <file:Documentation/admin-guide/bootconfig.rst> for details. 1424 1425 If unsure, say Y. 1426 1427config BOOT_CONFIG_FORCE 1428 bool "Force unconditional bootconfig processing" 1429 depends on BOOT_CONFIG 1430 default y if BOOT_CONFIG_EMBED 1431 help 1432 With this Kconfig option set, BOOT_CONFIG processing is carried 1433 out even when the "bootconfig" kernel-boot parameter is omitted. 1434 In fact, with this Kconfig option set, there is no way to 1435 make the kernel ignore the BOOT_CONFIG-supplied kernel-boot 1436 parameters. 1437 1438 If unsure, say N. 1439 1440config BOOT_CONFIG_EMBED 1441 bool "Embed bootconfig file in the kernel" 1442 depends on BOOT_CONFIG 1443 help 1444 Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the 1445 kernel. Usually, the bootconfig file is loaded with the initrd 1446 image. But if the system doesn't support initrd, this option will 1447 help you by embedding a bootconfig file while building the kernel. 1448 1449 If unsure, say N. 1450 1451config BOOT_CONFIG_EMBED_FILE 1452 string "Embedded bootconfig file path" 1453 depends on BOOT_CONFIG_EMBED 1454 help 1455 Specify a bootconfig file which will be embedded to the kernel. 1456 This bootconfig will be used if there is no initrd or no other 1457 bootconfig in the initrd. 1458 1459config INITRAMFS_PRESERVE_MTIME 1460 bool "Preserve cpio archive mtimes in initramfs" 1461 default y 1462 help 1463 Each entry in an initramfs cpio archive carries an mtime value. When 1464 enabled, extracted cpio items take this mtime, with directory mtime 1465 setting deferred until after creation of any child entries. 1466 1467 If unsure, say Y. 1468 1469config INITRAMFS_TEST 1470 bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS 1471 depends on BLK_DEV_INITRD && KUNIT=y 1472 default KUNIT_ALL_TESTS 1473 help 1474 Build KUnit tests for initramfs. See Documentation/dev-tools/kunit 1475 1476choice 1477 prompt "Compiler optimization level" 1478 default CC_OPTIMIZE_FOR_PERFORMANCE 1479 1480config CC_OPTIMIZE_FOR_PERFORMANCE 1481 bool "Optimize for performance (-O2)" 1482 help 1483 This is the default optimization level for the kernel, building 1484 with the "-O2" compiler flag for best performance and most 1485 helpful compile-time warnings. 1486 1487config CC_OPTIMIZE_FOR_SIZE 1488 bool "Optimize for size (-Os)" 1489 help 1490 Choosing this option will pass "-Os" to your compiler resulting 1491 in a smaller kernel. 1492 1493endchoice 1494 1495config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1496 bool 1497 help 1498 This requires that the arch annotates or otherwise protects 1499 its external entry points from being discarded. Linker scripts 1500 must also merge .text.*, .data.*, and .bss.* correctly into 1501 output sections. Care must be taken not to pull in unrelated 1502 sections (e.g., '.text.init'). Typically '.' in section names 1503 is used to distinguish them from label names / C identifiers. 1504 1505config LD_DEAD_CODE_DATA_ELIMINATION 1506 bool "Dead code and data elimination (EXPERIMENTAL)" 1507 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1508 depends on EXPERT 1509 depends on $(cc-option,-ffunction-sections -fdata-sections) 1510 depends on $(ld-option,--gc-sections) 1511 help 1512 Enable this if you want to do dead code and data elimination with 1513 the linker by compiling with -ffunction-sections -fdata-sections, 1514 and linking with --gc-sections. 1515 1516 This can reduce on disk and in-memory size of the kernel 1517 code and static data, particularly for small configs and 1518 on small systems. This has the possibility of introducing 1519 silently broken kernel if the required annotations are not 1520 present. This option is not well tested yet, so use at your 1521 own risk. 1522 1523config LD_ORPHAN_WARN 1524 def_bool y 1525 depends on ARCH_WANT_LD_ORPHAN_WARN 1526 depends on $(ld-option,--orphan-handling=warn) 1527 depends on $(ld-option,--orphan-handling=error) 1528 1529config LD_ORPHAN_WARN_LEVEL 1530 string 1531 depends on LD_ORPHAN_WARN 1532 default "error" if WERROR 1533 default "warn" 1534 1535config SYSCTL 1536 bool 1537 1538config HAVE_UID16 1539 bool 1540 1541config SYSCTL_EXCEPTION_TRACE 1542 bool 1543 help 1544 Enable support for /proc/sys/debug/exception-trace. 1545 1546config SYSCTL_ARCH_UNALIGN_NO_WARN 1547 bool 1548 help 1549 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1550 Allows arch to define/use @no_unaligned_warning to possibly warn 1551 about unaligned access emulation going on under the hood. 1552 1553config SYSCTL_ARCH_UNALIGN_ALLOW 1554 bool 1555 help 1556 Enable support for /proc/sys/kernel/unaligned-trap 1557 Allows arches to define/use @unaligned_enabled to runtime toggle 1558 the unaligned access emulation. 1559 see arch/parisc/kernel/unaligned.c for reference 1560 1561config SYSFS_SYSCALL 1562 bool "Sysfs syscall support" 1563 default n 1564 help 1565 sys_sysfs is an obsolete system call no longer supported in libc. 1566 Note that disabling this option is more secure but might break 1567 compatibility with some systems. 1568 1569 If unsure say N here. 1570 1571config HAVE_PCSPKR_PLATFORM 1572 bool 1573 1574menuconfig EXPERT 1575 bool "Configure standard kernel features (expert users)" 1576 # Unhide debug options, to make the on-by-default options visible 1577 select DEBUG_KERNEL 1578 help 1579 This option allows certain base kernel options and settings 1580 to be disabled or tweaked. This is for specialized 1581 environments which can tolerate a "non-standard" kernel. 1582 Only use this if you really know what you are doing. 1583 1584config UID16 1585 bool "Enable 16-bit UID system calls" if EXPERT 1586 depends on HAVE_UID16 && MULTIUSER 1587 default y 1588 help 1589 This enables the legacy 16-bit UID syscall wrappers. 1590 1591config MULTIUSER 1592 bool "Multiple users, groups and capabilities support" if EXPERT 1593 default y 1594 help 1595 This option enables support for non-root users, groups and 1596 capabilities. 1597 1598 If you say N here, all processes will run with UID 0, GID 0, and all 1599 possible capabilities. Saying N here also compiles out support for 1600 system calls related to UIDs, GIDs, and capabilities, such as setuid, 1601 setgid, and capset. 1602 1603 If unsure, say Y here. 1604 1605config SGETMASK_SYSCALL 1606 bool "sgetmask/ssetmask syscalls support" if EXPERT 1607 default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH 1608 help 1609 sys_sgetmask and sys_ssetmask are obsolete system calls 1610 no longer supported in libc but still enabled by default in some 1611 architectures. 1612 1613 If unsure, leave the default option here. 1614 1615config FHANDLE 1616 bool "open by fhandle syscalls" if EXPERT 1617 select EXPORTFS 1618 default y 1619 help 1620 If you say Y here, a user level program will be able to map 1621 file names to handle and then later use the handle for 1622 different file system operations. This is useful in implementing 1623 userspace file servers, which now track files using handles instead 1624 of names. The handle would remain the same even if file names 1625 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 1626 syscalls. 1627 1628config POSIX_TIMERS 1629 bool "Posix Clocks & timers" if EXPERT 1630 default y 1631 help 1632 This includes native support for POSIX timers to the kernel. 1633 Some embedded systems have no use for them and therefore they 1634 can be configured out to reduce the size of the kernel image. 1635 1636 When this option is disabled, the following syscalls won't be 1637 available: timer_create, timer_gettime: timer_getoverrun, 1638 timer_settime, timer_delete, clock_adjtime, getitimer, 1639 setitimer, alarm. Furthermore, the clock_settime, clock_gettime, 1640 clock_getres and clock_nanosleep syscalls will be limited to 1641 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. 1642 1643 If unsure say y. 1644 1645config PRINTK 1646 default y 1647 bool "Enable support for printk" if EXPERT 1648 select IRQ_WORK 1649 help 1650 This option enables normal printk support. Removing it 1651 eliminates most of the message strings from the kernel image 1652 and makes the kernel more or less silent. As this makes it 1653 very difficult to diagnose system problems, saying N here is 1654 strongly discouraged. 1655 1656config BUG 1657 bool "BUG() support" if EXPERT 1658 default y 1659 help 1660 Disabling this option eliminates support for BUG and WARN, reducing 1661 the size of your kernel image and potentially quietly ignoring 1662 numerous fatal conditions. You should only consider disabling this 1663 option for embedded systems with no facilities for reporting errors. 1664 Just say Y. 1665 1666config ELF_CORE 1667 depends on COREDUMP 1668 default y 1669 bool "Enable ELF core dumps" if EXPERT 1670 help 1671 Enable support for generating core dumps. Disabling saves about 4k. 1672 1673 1674config PCSPKR_PLATFORM 1675 bool "Enable PC-Speaker support" if EXPERT 1676 depends on HAVE_PCSPKR_PLATFORM 1677 select I8253_LOCK 1678 default y 1679 help 1680 This option allows to disable the internal PC-Speaker 1681 support, saving some memory. 1682 1683config BASE_SMALL 1684 bool "Enable smaller-sized data structures for core" if EXPERT 1685 help 1686 Enabling this option reduces the size of miscellaneous core 1687 kernel data structures. This saves memory on small machines, 1688 but may reduce performance. 1689 1690config FUTEX 1691 bool "Enable futex support" if EXPERT 1692 depends on !(SPARC32 && SMP) 1693 default y 1694 imply RT_MUTEXES 1695 help 1696 Disabling this option will cause the kernel to be built without 1697 support for "fast userspace mutexes". The resulting kernel may not 1698 run glibc-based applications correctly. 1699 1700config FUTEX_PI 1701 bool 1702 depends on FUTEX && RT_MUTEXES 1703 default y 1704 1705config EPOLL 1706 bool "Enable eventpoll support" if EXPERT 1707 default y 1708 help 1709 Disabling this option will cause the kernel to be built without 1710 support for epoll family of system calls. 1711 1712config SIGNALFD 1713 bool "Enable signalfd() system call" if EXPERT 1714 default y 1715 help 1716 Enable the signalfd() system call that allows to receive signals 1717 on a file descriptor. 1718 1719 If unsure, say Y. 1720 1721config TIMERFD 1722 bool "Enable timerfd() system call" if EXPERT 1723 default y 1724 help 1725 Enable the timerfd() system call that allows to receive timer 1726 events on a file descriptor. 1727 1728 If unsure, say Y. 1729 1730config EVENTFD 1731 bool "Enable eventfd() system call" if EXPERT 1732 default y 1733 help 1734 Enable the eventfd() system call that allows to receive both 1735 kernel notification (ie. KAIO) or userspace notifications. 1736 1737 If unsure, say Y. 1738 1739config SHMEM 1740 bool "Use full shmem filesystem" if EXPERT 1741 default y 1742 depends on MMU 1743 help 1744 The shmem is an internal filesystem used to manage shared memory. 1745 It is backed by swap and manages resource limits. It is also exported 1746 to userspace as tmpfs if TMPFS is enabled. Disabling this 1747 option replaces shmem and tmpfs with the much simpler ramfs code, 1748 which may be appropriate on small systems without swap. 1749 1750config AIO 1751 bool "Enable AIO support" if EXPERT 1752 default y 1753 help 1754 This option enables POSIX asynchronous I/O which may by used 1755 by some high performance threaded applications. Disabling 1756 this option saves about 7k. 1757 1758config IO_URING 1759 bool "Enable IO uring support" if EXPERT 1760 select IO_WQ 1761 default y 1762 help 1763 This option enables support for the io_uring interface, enabling 1764 applications to submit and complete IO through submission and 1765 completion rings that are shared between the kernel and application. 1766 1767config GCOV_PROFILE_URING 1768 bool "Enable GCOV profiling on the io_uring subsystem" 1769 depends on GCOV_KERNEL 1770 help 1771 Enable GCOV profiling on the io_uring subsystem, to facilitate 1772 code coverage testing. 1773 1774 If unsure, say N. 1775 1776 Note that this will have a negative impact on the performance of 1777 the io_uring subsystem, hence this should only be enabled for 1778 specific test purposes. 1779 1780config ADVISE_SYSCALLS 1781 bool "Enable madvise/fadvise syscalls" if EXPERT 1782 default y 1783 help 1784 This option enables the madvise and fadvise syscalls, used by 1785 applications to advise the kernel about their future memory or file 1786 usage, improving performance. If building an embedded system where no 1787 applications use these syscalls, you can disable this option to save 1788 space. 1789 1790config MEMBARRIER 1791 bool "Enable membarrier() system call" if EXPERT 1792 default y 1793 help 1794 Enable the membarrier() system call that allows issuing memory 1795 barriers across all running threads, which can be used to distribute 1796 the cost of user-space memory barriers asymmetrically by transforming 1797 pairs of memory barriers into pairs consisting of membarrier() and a 1798 compiler barrier. 1799 1800 If unsure, say Y. 1801 1802config KCMP 1803 bool "Enable kcmp() system call" if EXPERT 1804 help 1805 Enable the kernel resource comparison system call. It provides 1806 user-space with the ability to compare two processes to see if they 1807 share a common resource, such as a file descriptor or even virtual 1808 memory space. 1809 1810 If unsure, say N. 1811 1812config RSEQ 1813 bool "Enable rseq() system call" if EXPERT 1814 default y 1815 depends on HAVE_RSEQ 1816 select MEMBARRIER 1817 help 1818 Enable the restartable sequences system call. It provides a 1819 user-space cache for the current CPU number value, which 1820 speeds up getting the current CPU number from user-space, 1821 as well as an ABI to speed up user-space operations on 1822 per-CPU data. 1823 1824 If unsure, say Y. 1825 1826config DEBUG_RSEQ 1827 default n 1828 bool "Enable debugging of rseq() system call" if EXPERT 1829 depends on RSEQ && DEBUG_KERNEL 1830 help 1831 Enable extra debugging checks for the rseq system call. 1832 1833 If unsure, say N. 1834 1835config CACHESTAT_SYSCALL 1836 bool "Enable cachestat() system call" if EXPERT 1837 default y 1838 help 1839 Enable the cachestat system call, which queries the page cache 1840 statistics of a file (number of cached pages, dirty pages, 1841 pages marked for writeback, (recently) evicted pages). 1842 1843 If unsure say Y here. 1844 1845config PC104 1846 bool "PC/104 support" if EXPERT 1847 help 1848 Expose PC/104 form factor device drivers and options available for 1849 selection and configuration. Enable this option if your target 1850 machine has a PC/104 bus. 1851 1852config KALLSYMS 1853 bool "Load all symbols for debugging/ksymoops" if EXPERT 1854 default y 1855 help 1856 Say Y here to let the kernel print out symbolic crash information and 1857 symbolic stack backtraces. This increases the size of the kernel 1858 somewhat, as all symbols have to be loaded into the kernel image. 1859 1860config KALLSYMS_SELFTEST 1861 bool "Test the basic functions and performance of kallsyms" 1862 depends on KALLSYMS 1863 default n 1864 help 1865 Test the basic functions and performance of some interfaces, such as 1866 kallsyms_lookup_name. It also calculates the compression rate of the 1867 kallsyms compression algorithm for the current symbol set. 1868 1869 Start self-test automatically after system startup. Suggest executing 1870 "dmesg | grep kallsyms_selftest" to collect test results. "finish" is 1871 displayed in the last line, indicating that the test is complete. 1872 1873config KALLSYMS_ALL 1874 bool "Include all symbols in kallsyms" 1875 depends on DEBUG_KERNEL && KALLSYMS 1876 help 1877 Normally kallsyms only contains the symbols of functions for nicer 1878 OOPS messages and backtraces (i.e., symbols from the text and inittext 1879 sections). This is sufficient for most cases. And only if you want to 1880 enable kernel live patching, or other less common use cases (e.g., 1881 when a debugger is used) all symbols are required (i.e., names of 1882 variables from the data sections, etc). 1883 1884 This option makes sure that all symbols are loaded into the kernel 1885 image (i.e., symbols from all sections) in cost of increased kernel 1886 size (depending on the kernel configuration, it may be 300KiB or 1887 something like this). 1888 1889 Say N unless you really need all symbols, or kernel live patching. 1890 1891# end of the "standard kernel features (expert users)" menu 1892 1893config ARCH_HAS_MEMBARRIER_CALLBACKS 1894 bool 1895 1896config ARCH_HAS_MEMBARRIER_SYNC_CORE 1897 bool 1898 1899config ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 1900 bool 1901 help 1902 Control MSEAL_SYSTEM_MAPPINGS access based on architecture. 1903 1904 A 64-bit kernel is required for the memory sealing feature. 1905 No specific hardware features from the CPU are needed. 1906 1907 To enable this feature, the architecture needs to update their 1908 special mappings calls to include the sealing flag and confirm 1909 that it doesn't unmap/remap system mappings during the life 1910 time of the process. The existence of this flag for an architecture 1911 implies that it does not require the remapping of the system 1912 mappings during process lifetime, so sealing these mappings is safe 1913 from a kernel perspective. 1914 1915 After the architecture enables this, a distribution can set 1916 CONFIG_MSEAL_SYSTEM_MAPPING to manage access to the feature. 1917 1918 For complete descriptions of memory sealing, please see 1919 Documentation/userspace-api/mseal.rst 1920 1921config HAVE_PERF_EVENTS 1922 bool 1923 help 1924 See tools/perf/design.txt for details. 1925 1926config GUEST_PERF_EVENTS 1927 bool 1928 depends on HAVE_PERF_EVENTS 1929 1930config PERF_USE_VMALLOC 1931 bool 1932 help 1933 See tools/perf/design.txt for details 1934 1935menu "Kernel Performance Events And Counters" 1936 1937config PERF_EVENTS 1938 bool "Kernel performance events and counters" 1939 default y if PROFILING 1940 depends on HAVE_PERF_EVENTS 1941 select IRQ_WORK 1942 help 1943 Enable kernel support for various performance events provided 1944 by software and hardware. 1945 1946 Software events are supported either built-in or via the 1947 use of generic tracepoints. 1948 1949 Most modern CPUs support performance events via performance 1950 counter registers. These registers count the number of certain 1951 types of hw events: such as instructions executed, cachemisses 1952 suffered, or branches mis-predicted - without slowing down the 1953 kernel or applications. These registers can also trigger interrupts 1954 when a threshold number of events have passed - and can thus be 1955 used to profile the code that runs on that CPU. 1956 1957 The Linux Performance Event subsystem provides an abstraction of 1958 these software and hardware event capabilities, available via a 1959 system call and used by the "perf" utility in tools/perf/. It 1960 provides per task and per CPU counters, and it provides event 1961 capabilities on top of those. 1962 1963 Say Y if unsure. 1964 1965config DEBUG_PERF_USE_VMALLOC 1966 default n 1967 bool "Debug: use vmalloc to back perf mmap() buffers" 1968 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC 1969 select PERF_USE_VMALLOC 1970 help 1971 Use vmalloc memory to back perf mmap() buffers. 1972 1973 Mostly useful for debugging the vmalloc code on platforms 1974 that don't require it. 1975 1976 Say N if unsure. 1977 1978endmenu 1979 1980config SYSTEM_DATA_VERIFICATION 1981 def_bool n 1982 select SYSTEM_TRUSTED_KEYRING 1983 select KEYS 1984 select CRYPTO 1985 select CRYPTO_RSA 1986 select ASYMMETRIC_KEY_TYPE 1987 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 1988 select ASN1 1989 select OID_REGISTRY 1990 select X509_CERTIFICATE_PARSER 1991 select PKCS7_MESSAGE_PARSER 1992 help 1993 Provide PKCS#7 message verification using the contents of the system 1994 trusted keyring to provide public keys. This then can be used for 1995 module verification, kexec image verification and firmware blob 1996 verification. 1997 1998config PROFILING 1999 bool "Profiling support" 2000 help 2001 Say Y here to enable the extended profiling support mechanisms used 2002 by profilers. 2003 2004config RUST 2005 bool "Rust support" 2006 depends on HAVE_RUST 2007 depends on RUST_IS_AVAILABLE 2008 select EXTENDED_MODVERSIONS if MODVERSIONS 2009 depends on !MODVERSIONS || GENDWARFKSYMS 2010 depends on !GCC_PLUGIN_RANDSTRUCT 2011 depends on !RANDSTRUCT 2012 depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO) 2013 depends on !CFI_CLANG || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC 2014 select CFI_ICALL_NORMALIZE_INTEGERS if CFI_CLANG 2015 depends on !CALL_PADDING || RUSTC_VERSION >= 108100 2016 depends on !KASAN_SW_TAGS 2017 depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300 2018 help 2019 Enables Rust support in the kernel. 2020 2021 This allows other Rust-related options, like drivers written in Rust, 2022 to be selected. 2023 2024 It is also required to be able to load external kernel modules 2025 written in Rust. 2026 2027 See Documentation/rust/ for more information. 2028 2029 If unsure, say N. 2030 2031config RUSTC_VERSION_TEXT 2032 string 2033 depends on RUST 2034 default "$(RUSTC_VERSION_TEXT)" 2035 help 2036 See `CC_VERSION_TEXT`. 2037 2038config BINDGEN_VERSION_TEXT 2039 string 2040 depends on RUST 2041 # The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0 2042 # (https://github.com/rust-lang/rust-bindgen/pull/2678) and 0.71.0 2043 # (https://github.com/rust-lang/rust-bindgen/pull/3040). It can be removed 2044 # when the minimum version is upgraded past the latter (0.69.1 and 0.71.1 2045 # both fixed the issue). 2046 default "$(shell,$(BINDGEN) --version workaround-for-0.69.0 2>/dev/null)" 2047 2048# 2049# Place an empty function call at each tracepoint site. Can be 2050# dynamically changed for a probe function. 2051# 2052config TRACEPOINTS 2053 bool 2054 select TASKS_TRACE_RCU 2055 2056source "kernel/Kconfig.kexec" 2057 2058endmenu # General setup 2059 2060source "arch/Kconfig" 2061 2062config RT_MUTEXES 2063 bool 2064 default y if PREEMPT_RT 2065 2066config MODULE_SIG_FORMAT 2067 def_bool n 2068 select SYSTEM_DATA_VERIFICATION 2069 2070source "kernel/module/Kconfig" 2071 2072config INIT_ALL_POSSIBLE 2073 bool 2074 help 2075 Back when each arch used to define their own cpu_online_mask and 2076 cpu_possible_mask, some of them chose to initialize cpu_possible_mask 2077 with all 1s, and others with all 0s. When they were centralised, 2078 it was better to provide this option than to break all the archs 2079 and have several arch maintainers pursuing me down dark alleys. 2080 2081source "block/Kconfig" 2082 2083config PREEMPT_NOTIFIERS 2084 bool 2085 2086config PADATA 2087 depends on SMP 2088 bool 2089 2090config ASN1 2091 tristate 2092 help 2093 Build a simple ASN.1 grammar compiler that produces a bytecode output 2094 that can be interpreted by the ASN.1 stream decoder and used to 2095 inform it as to what tags are to be expected in a stream and what 2096 functions to call on what tags. 2097 2098source "kernel/Kconfig.locks" 2099 2100config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 2101 bool 2102 2103config ARCH_HAS_PREPARE_SYNC_CORE_CMD 2104 bool 2105 2106config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2107 bool 2108 2109# It may be useful for an architecture to override the definitions of the 2110# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> 2111# and the COMPAT_ variants in <linux/compat.h>, in particular to use a 2112# different calling convention for syscalls. They can also override the 2113# macros for not-implemented syscalls in kernel/sys_ni.c and 2114# kernel/time/posix-stubs.c. All these overrides need to be available in 2115# <asm/syscall_wrapper.h>. 2116config ARCH_HAS_SYSCALL_WRAPPER 2117 def_bool n 2118