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 # Detect basic support 103 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) 104 # Detect clang (< v17) scoped label issues 105 depends on $(success,echo 'void b(void **);void* c(void);int f(void){{asm goto(""::::l0);return 0;l0:return 1;}void *x __attribute__((cleanup(b)))=c();{asm goto(""::::l1);return 2;l1:return 3;}}' | $(CC) -x c - -c -o /dev/null) 106 107config CC_HAS_ASM_GOTO_TIED_OUTPUT 108 depends on CC_HAS_ASM_GOTO_OUTPUT 109 # Detect buggy gcc and clang, fixed in gcc-11 clang-14. 110 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) 111 112config TOOLS_SUPPORT_RELR 113 def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh) 114 115config CC_HAS_ASM_INLINE 116 def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null) 117 118config CC_HAS_NO_PROFILE_FN_ATTR 119 def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror) 120 121config CC_HAS_COUNTED_BY 122 bool 123 # clang needs to be at least 20.1.0 to avoid potential crashes 124 # when building structures that contain __counted_by 125 # https://github.com/ClangBuiltLinux/linux/issues/2114 126 # https://github.com/llvm/llvm-project/commit/160fb1121cdf703c3ef5e61fb26c5659eb581489 127 default y if CC_IS_CLANG && CLANG_VERSION >= 200100 128 # supported since gcc 15.1.0 129 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896 130 default y if CC_IS_GCC && GCC_VERSION >= 150100 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_SPAN_FILE 144 def_bool RUSTC_VERSION >= 108800 145 146config RUSTC_HAS_UNNECESSARY_TRANSMUTES 147 def_bool RUSTC_VERSION >= 108800 148 149config RUSTC_HAS_FILE_WITH_NUL 150 def_bool RUSTC_VERSION >= 108900 151 152config RUSTC_HAS_FILE_AS_C_STR 153 def_bool RUSTC_VERSION >= 109100 154 155config PAHOLE_VERSION 156 int 157 default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE)) 158 159config CONSTRUCTORS 160 bool 161 162config IRQ_WORK 163 def_bool y if SMP 164 165config BUILDTIME_TABLE_SORT 166 bool 167 168config THREAD_INFO_IN_TASK 169 bool 170 help 171 Select this to move thread_info off the stack into task_struct. To 172 make this work, an arch will need to remove all thread_info fields 173 except flags and fix any runtime bugs. 174 175 One subtle change that will be needed is to use try_get_task_stack() 176 and put_task_stack() in save_thread_stack_tsk() and get_wchan(). 177 178menu "General setup" 179 180config BROKEN 181 bool 182 help 183 This option allows you to choose whether you want to try to 184 compile (and fix) old drivers that haven't been updated to 185 new infrastructure. 186 187config BROKEN_ON_SMP 188 bool 189 depends on BROKEN || !SMP 190 default y 191 192config INIT_ENV_ARG_LIMIT 193 int 194 default 32 if !UML 195 default 128 if UML 196 help 197 Maximum of each of the number of arguments and environment 198 variables passed to init from the kernel command line. 199 200config COMPILE_TEST 201 bool "Compile also drivers which will not load" 202 depends on HAS_IOMEM 203 help 204 Some drivers can be compiled on a different platform than they are 205 intended to be run on. Despite they cannot be loaded there (or even 206 when they load they cannot be used due to missing HW support), 207 developers still, opposing to distributors, might want to build such 208 drivers to compile-test them. 209 210 If you are a developer and want to build everything available, say Y 211 here. If you are a user/distributor, say N here to exclude useless 212 drivers to be distributed. 213 214config WERROR 215 bool "Compile the kernel with warnings as errors" 216 default COMPILE_TEST 217 help 218 A kernel build should not cause any compiler warnings, and this 219 enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags 220 to enforce that rule by default. Certain warnings from other tools 221 such as the linker may be upgraded to errors with this option as 222 well. 223 224 However, if you have a new (or very old) compiler or linker with odd 225 and unusual warnings, or you have some architecture with problems, 226 you may need to disable this config option in order to 227 successfully build the kernel. 228 229 If in doubt, say Y. 230 231config UAPI_HEADER_TEST 232 bool "Compile test UAPI headers" 233 depends on HEADERS_INSTALL && CC_CAN_LINK 234 help 235 Compile test headers exported to user-space to ensure they are 236 self-contained, i.e. compilable as standalone units. 237 238 If you are a developer or tester and want to ensure the exported 239 headers are self-contained, say Y here. Otherwise, choose N. 240 241config LOCALVERSION 242 string "Local version - append to kernel release" 243 help 244 Append an extra string to the end of your kernel version. 245 This will show up when you type uname, for example. 246 The string you set here will be appended after the contents of 247 any files with a filename matching localversion* in your 248 object and source tree, in that order. Your total string can 249 be a maximum of 64 characters. 250 251config LOCALVERSION_AUTO 252 bool "Automatically append version information to the version string" 253 default y 254 depends on !COMPILE_TEST 255 help 256 This will try to automatically determine if the current tree is a 257 release tree by looking for git tags that belong to the current 258 top of tree revision. 259 260 A string of the format -gxxxxxxxx will be added to the localversion 261 if a git-based tree is found. The string generated by this will be 262 appended after any matching localversion* files, and after the value 263 set in CONFIG_LOCALVERSION. 264 265 (The actual string used here is the first 12 characters produced 266 by running the command: 267 268 $ git rev-parse --verify HEAD 269 270 which is done within the script "scripts/setlocalversion".) 271 272config BUILD_SALT 273 string "Build ID Salt" 274 default "" 275 help 276 The build ID is used to link binaries and their debug info. Setting 277 this option will use the value in the calculation of the build id. 278 This is mostly useful for distributions which want to ensure the 279 build is unique between builds. It's safe to leave the default. 280 281config HAVE_KERNEL_GZIP 282 bool 283 284config HAVE_KERNEL_BZIP2 285 bool 286 287config HAVE_KERNEL_LZMA 288 bool 289 290config HAVE_KERNEL_XZ 291 bool 292 293config HAVE_KERNEL_LZO 294 bool 295 296config HAVE_KERNEL_LZ4 297 bool 298 299config HAVE_KERNEL_ZSTD 300 bool 301 302config HAVE_KERNEL_UNCOMPRESSED 303 bool 304 305choice 306 prompt "Kernel compression mode" 307 default KERNEL_GZIP 308 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 309 help 310 The linux kernel is a kind of self-extracting executable. 311 Several compression algorithms are available, which differ 312 in efficiency, compression and decompression speed. 313 Compression speed is only relevant when building a kernel. 314 Decompression speed is relevant at each boot. 315 316 If you have any problems with bzip2 or lzma compressed 317 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 318 version of this functionality (bzip2 only), for 2.4, was 319 supplied by Christian Ludwig) 320 321 High compression options are mostly useful for users, who 322 are low on disk space (embedded systems), but for whom ram 323 size matters less. 324 325 If in doubt, select 'gzip' 326 327config KERNEL_GZIP 328 bool "Gzip" 329 depends on HAVE_KERNEL_GZIP 330 help 331 The old and tried gzip compression. It provides a good balance 332 between compression ratio and decompression speed. 333 334config KERNEL_BZIP2 335 bool "Bzip2" 336 depends on HAVE_KERNEL_BZIP2 337 help 338 Its compression ratio and speed is intermediate. 339 Decompression speed is slowest among the choices. The kernel 340 size is about 10% smaller with bzip2, in comparison to gzip. 341 Bzip2 uses a large amount of memory. For modern kernels you 342 will need at least 8MB RAM or more for booting. 343 344config KERNEL_LZMA 345 bool "LZMA" 346 depends on HAVE_KERNEL_LZMA 347 help 348 This compression algorithm's ratio is best. Decompression speed 349 is between gzip and bzip2. Compression is slowest. 350 The kernel size is about 33% smaller with LZMA in comparison to gzip. 351 352config KERNEL_XZ 353 bool "XZ" 354 depends on HAVE_KERNEL_XZ 355 help 356 XZ uses the LZMA2 algorithm and instruction set specific 357 BCJ filters which can improve compression ratio of executable 358 code. The size of the kernel is about 30% smaller with XZ in 359 comparison to gzip. On architectures for which there is a BCJ 360 filter (i386, x86_64, ARM, ARM64, RISC-V, big endian PowerPC, 361 and SPARC), XZ will create a few percent smaller kernel than 362 plain LZMA. 363 364 The speed is about the same as with LZMA: The decompression 365 speed of XZ is better than that of bzip2 but worse than gzip 366 and LZO. Compression is slow. 367 368config KERNEL_LZO 369 bool "LZO" 370 depends on HAVE_KERNEL_LZO 371 help 372 Its compression ratio is the poorest among the choices. The kernel 373 size is about 10% bigger than gzip; however its speed 374 (both compression and decompression) is the fastest. 375 376config KERNEL_LZ4 377 bool "LZ4" 378 depends on HAVE_KERNEL_LZ4 379 help 380 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. 381 A preliminary version of LZ4 de/compression tool is available at 382 <https://code.google.com/p/lz4/>. 383 384 Its compression ratio is worse than LZO. The size of the kernel 385 is about 8% bigger than LZO. But the decompression speed is 386 faster than LZO. 387 388config KERNEL_ZSTD 389 bool "ZSTD" 390 depends on HAVE_KERNEL_ZSTD 391 help 392 ZSTD is a compression algorithm targeting intermediate compression 393 with fast decompression speed. It will compress better than GZIP and 394 decompress around the same speed as LZO, but slower than LZ4. You 395 will need at least 192 KB RAM or more for booting. The zstd command 396 line tool is required for compression. 397 398config KERNEL_UNCOMPRESSED 399 bool "None" 400 depends on HAVE_KERNEL_UNCOMPRESSED 401 help 402 Produce uncompressed kernel image. This option is usually not what 403 you want. It is useful for debugging the kernel in slow simulation 404 environments, where decompressing and moving the kernel is awfully 405 slow. This option allows early boot code to skip the decompressor 406 and jump right at uncompressed kernel image. 407 408endchoice 409 410config DEFAULT_INIT 411 string "Default init path" 412 default "" 413 help 414 This option determines the default init for the system if no init= 415 option is passed on the kernel command line. If the requested path is 416 not present, we will still then move on to attempting further 417 locations (e.g. /sbin/init, etc). If this is empty, we will just use 418 the fallback list when init= is not passed. 419 420config DEFAULT_HOSTNAME 421 string "Default hostname" 422 default "(none)" 423 help 424 This option determines the default system hostname before userspace 425 calls sethostname(2). The kernel traditionally uses "(none)" here, 426 but you may wish to use a different default here to make a minimal 427 system more usable with less configuration. 428 429config SYSVIPC 430 bool "System V IPC" 431 help 432 Inter Process Communication is a suite of library functions and 433 system calls which let processes (running programs) synchronize and 434 exchange information. It is generally considered to be a good thing, 435 and some programs won't run unless you say Y here. In particular, if 436 you want to run the DOS emulator dosemu under Linux (read the 437 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 438 you'll need to say Y here. 439 440 You can find documentation about IPC with "info ipc" and also in 441 section 6.4 of the Linux Programmer's Guide, available from 442 <http://www.tldp.org/guides.html>. 443 444config SYSVIPC_SYSCTL 445 bool 446 depends on SYSVIPC 447 depends on SYSCTL 448 default y 449 450config SYSVIPC_COMPAT 451 def_bool y 452 depends on COMPAT && SYSVIPC 453 454config POSIX_MQUEUE 455 bool "POSIX Message Queues" 456 depends on NET 457 help 458 POSIX variant of message queues is a part of IPC. In POSIX message 459 queues every message has a priority which decides about succession 460 of receiving it by a process. If you want to compile and run 461 programs written e.g. for Solaris with use of its POSIX message 462 queues (functions mq_*) say Y here. 463 464 POSIX message queues are visible as a filesystem called 'mqueue' 465 and can be mounted somewhere if you want to do filesystem 466 operations on message queues. 467 468 If unsure, say Y. 469 470config POSIX_MQUEUE_SYSCTL 471 bool 472 depends on POSIX_MQUEUE 473 depends on SYSCTL 474 default y 475 476config WATCH_QUEUE 477 bool "General notification queue" 478 default n 479 help 480 481 This is a general notification queue for the kernel to pass events to 482 userspace by splicing them into pipes. It can be used in conjunction 483 with watches for key/keyring change notifications and device 484 notifications. 485 486 See Documentation/core-api/watch_queue.rst 487 488config CROSS_MEMORY_ATTACH 489 bool "Enable process_vm_readv/writev syscalls" 490 depends on MMU 491 default y 492 help 493 Enabling this option adds the system calls process_vm_readv and 494 process_vm_writev which allow a process with the correct privileges 495 to directly read from or write to another process' address space. 496 See the man page for more details. 497 498config AUDIT 499 bool "Auditing support" 500 depends on NET 501 help 502 Enable auditing infrastructure that can be used with another 503 kernel subsystem, such as SELinux (which requires this for 504 logging of avc messages output). System call auditing is included 505 on architectures which support it. 506 507config HAVE_ARCH_AUDITSYSCALL 508 bool 509 510config AUDITSYSCALL 511 def_bool y 512 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL 513 select FSNOTIFY 514 515source "kernel/irq/Kconfig" 516source "kernel/time/Kconfig" 517source "kernel/bpf/Kconfig" 518source "kernel/Kconfig.preempt" 519 520menu "CPU/Task time and stats accounting" 521 522config VIRT_CPU_ACCOUNTING 523 bool 524 525choice 526 prompt "Cputime accounting" 527 default TICK_CPU_ACCOUNTING 528 529# Kind of a stub config for the pure tick based cputime accounting 530config TICK_CPU_ACCOUNTING 531 bool "Simple tick based cputime accounting" 532 depends on !S390 && !NO_HZ_FULL 533 help 534 This is the basic tick based cputime accounting that maintains 535 statistics about user, system and idle time spent on per jiffies 536 granularity. 537 538 If unsure, say Y. 539 540config VIRT_CPU_ACCOUNTING_NATIVE 541 bool "Deterministic task and CPU time accounting" 542 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL 543 select VIRT_CPU_ACCOUNTING 544 help 545 Select this option to enable more accurate task and CPU time 546 accounting. This is done by reading a CPU counter on each 547 kernel entry and exit and on transitions within the kernel 548 between system, softirq and hardirq state, so there is a 549 small performance impact. In the case of s390 or IBM POWER > 5, 550 this also enables accounting of stolen time on logically-partitioned 551 systems. 552 553config VIRT_CPU_ACCOUNTING_GEN 554 bool "Full dynticks CPU time accounting" 555 depends on HAVE_CONTEXT_TRACKING_USER 556 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN 557 depends on GENERIC_CLOCKEVENTS 558 select VIRT_CPU_ACCOUNTING 559 select CONTEXT_TRACKING_USER 560 help 561 Select this option to enable task and CPU time accounting on full 562 dynticks systems. This accounting is implemented by watching every 563 kernel-user boundaries using the context tracking subsystem. 564 The accounting is thus performed at the expense of some significant 565 overhead. 566 567 For now this is only useful if you are working on the full 568 dynticks subsystem development. 569 570 If unsure, say N. 571 572endchoice 573 574config IRQ_TIME_ACCOUNTING 575 bool "Fine granularity task level IRQ time accounting" 576 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE 577 help 578 Select this option to enable fine granularity task irq time 579 accounting. This is done by reading a timestamp on each 580 transitions between softirq and hardirq state, so there can be a 581 small performance impact. 582 583 If in doubt, say N here. 584 585config HAVE_SCHED_AVG_IRQ 586 def_bool y 587 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING 588 depends on SMP 589 590config SCHED_HW_PRESSURE 591 bool 592 default y if ARM && ARM_CPU_TOPOLOGY 593 default y if ARM64 594 depends on SMP 595 depends on CPU_FREQ_THERMAL 596 help 597 Select this option to enable HW pressure accounting in the 598 scheduler. HW pressure is the value conveyed to the scheduler 599 that reflects the reduction in CPU compute capacity resulted from 600 HW throttling. HW throttling occurs when the performance of 601 a CPU is capped due to high operating temperatures as an example. 602 603 If selected, the scheduler will be able to balance tasks accordingly, 604 i.e. put less load on throttled CPUs than on non/less throttled ones. 605 606 This requires the architecture to implement 607 arch_update_hw_pressure() and arch_scale_thermal_pressure(). 608 609config BSD_PROCESS_ACCT 610 bool "BSD Process Accounting" 611 depends on MULTIUSER 612 help 613 If you say Y here, a user level program will be able to instruct the 614 kernel (via a special system call) to write process accounting 615 information to a file: whenever a process exits, information about 616 that process will be appended to the file by the kernel. The 617 information includes things such as creation time, owning user, 618 command name, memory usage, controlling terminal etc. (the complete 619 list is in the struct acct in <file:include/linux/acct.h>). It is 620 up to the user level program to do useful things with this 621 information. This is generally a good idea, so say Y. 622 623config BSD_PROCESS_ACCT_V3 624 bool "BSD Process Accounting version 3 file format" 625 depends on BSD_PROCESS_ACCT 626 default n 627 help 628 If you say Y here, the process accounting information is written 629 in a new file format that also logs the process IDs of each 630 process and its parent. Note that this file format is incompatible 631 with previous v0/v1/v2 file formats, so you will need updated tools 632 for processing it. A preliminary version of these tools is available 633 at <http://www.gnu.org/software/acct/>. 634 635config TASKSTATS 636 bool "Export task/process statistics through netlink" 637 depends on NET 638 depends on MULTIUSER 639 default n 640 help 641 Export selected statistics for tasks/processes through the 642 generic netlink interface. Unlike BSD process accounting, the 643 statistics are available during the lifetime of tasks/processes as 644 responses to commands. Like BSD accounting, they are sent to user 645 space on task exit. 646 647 Say N if unsure. 648 649config TASK_DELAY_ACCT 650 bool "Enable per-task delay accounting" 651 depends on TASKSTATS 652 select SCHED_INFO 653 help 654 Collect information on time spent by a task waiting for system 655 resources like cpu, synchronous block I/O completion and swapping 656 in pages. Such statistics can help in setting a task's priorities 657 relative to other tasks for cpu, io, rss limits etc. 658 659 Say N if unsure. 660 661config TASK_XACCT 662 bool "Enable extended accounting over taskstats" 663 depends on TASKSTATS 664 help 665 Collect extended task accounting data and send the data 666 to userland for processing over the taskstats interface. 667 668 Say N if unsure. 669 670config TASK_IO_ACCOUNTING 671 bool "Enable per-task storage I/O accounting" 672 depends on TASK_XACCT 673 help 674 Collect information on the number of bytes of storage I/O which this 675 task has caused. 676 677 Say N if unsure. 678 679config PSI 680 bool "Pressure stall information tracking" 681 select KERNFS 682 help 683 Collect metrics that indicate how overcommitted the CPU, memory, 684 and IO capacity are in the system. 685 686 If you say Y here, the kernel will create /proc/pressure/ with the 687 pressure statistics files cpu, memory, and io. These will indicate 688 the share of walltime in which some or all tasks in the system are 689 delayed due to contention of the respective resource. 690 691 In kernels with cgroup support, cgroups (cgroup2 only) will 692 have cpu.pressure, memory.pressure, and io.pressure files, 693 which aggregate pressure stalls for the grouped tasks only. 694 695 For more details see Documentation/accounting/psi.rst. 696 697 Say N if unsure. 698 699config PSI_DEFAULT_DISABLED 700 bool "Require boot parameter to enable pressure stall information tracking" 701 default n 702 depends on PSI 703 help 704 If set, pressure stall information tracking will be disabled 705 per default but can be enabled through passing psi=1 on the 706 kernel commandline during boot. 707 708 This feature adds some code to the task wakeup and sleep 709 paths of the scheduler. The overhead is too low to affect 710 common scheduling-intense workloads in practice (such as 711 webservers, memcache), but it does show up in artificial 712 scheduler stress tests, such as hackbench. 713 714 If you are paranoid and not sure what the kernel will be 715 used for, say Y. 716 717 Say N if unsure. 718 719endmenu # "CPU/Task time and stats accounting" 720 721config CPU_ISOLATION 722 bool "CPU isolation" 723 depends on SMP 724 default y 725 help 726 Make sure that CPUs running critical tasks are not disturbed by 727 any source of "noise" such as unbound workqueues, timers, kthreads... 728 Unbound jobs get offloaded to housekeeping CPUs. This is driven by 729 the "isolcpus=" boot parameter. 730 731 Say Y if unsure. 732 733source "kernel/rcu/Kconfig" 734 735config IKCONFIG 736 tristate "Kernel .config support" 737 help 738 This option enables the complete Linux kernel ".config" file 739 contents to be saved in the kernel. It provides documentation 740 of which kernel options are used in a running kernel or in an 741 on-disk kernel. This information can be extracted from the kernel 742 image file with the script scripts/extract-ikconfig and used as 743 input to rebuild the current kernel or to build another kernel. 744 It can also be extracted from a running kernel by reading 745 /proc/config.gz if enabled (below). 746 747config IKCONFIG_PROC 748 bool "Enable access to .config through /proc/config.gz" 749 depends on IKCONFIG && PROC_FS 750 help 751 This option enables access to the kernel configuration file 752 through /proc/config.gz. 753 754config IKHEADERS 755 tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz" 756 depends on SYSFS 757 help 758 This option enables access to the in-kernel headers that are generated during 759 the build process. These can be used to build eBPF tracing programs, 760 or similar programs. If you build the headers as a module, a module called 761 kheaders.ko is built which can be loaded on-demand to get access to headers. 762 763config LOG_BUF_SHIFT 764 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 765 range 12 25 766 default 17 767 depends on PRINTK 768 help 769 Select the minimal kernel log buffer size as a power of 2. 770 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config 771 parameter, see below. Any higher size also might be forced 772 by "log_buf_len" boot parameter. 773 774 Examples: 775 17 => 128 KB 776 16 => 64 KB 777 15 => 32 KB 778 14 => 16 KB 779 13 => 8 KB 780 12 => 4 KB 781 782config LOG_CPU_MAX_BUF_SHIFT 783 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" 784 depends on SMP 785 range 0 21 786 default 0 if BASE_SMALL 787 default 12 788 depends on PRINTK 789 help 790 This option allows to increase the default ring buffer size 791 according to the number of CPUs. The value defines the contribution 792 of each CPU as a power of 2. The used space is typically only few 793 lines however it might be much more when problems are reported, 794 e.g. backtraces. 795 796 The increased size means that a new buffer has to be allocated and 797 the original static one is unused. It makes sense only on systems 798 with more CPUs. Therefore this value is used only when the sum of 799 contributions is greater than the half of the default kernel ring 800 buffer as defined by LOG_BUF_SHIFT. The default values are set 801 so that more than 16 CPUs are needed to trigger the allocation. 802 803 Also this option is ignored when "log_buf_len" kernel parameter is 804 used as it forces an exact (power of two) size of the ring buffer. 805 806 The number of possible CPUs is used for this computation ignoring 807 hotplugging making the computation optimal for the worst case 808 scenario while allowing a simple algorithm to be used from bootup. 809 810 Examples shift values and their meaning: 811 17 => 128 KB for each CPU 812 16 => 64 KB for each CPU 813 15 => 32 KB for each CPU 814 14 => 16 KB for each CPU 815 13 => 8 KB for each CPU 816 12 => 4 KB for each CPU 817 818config PRINTK_INDEX 819 bool "Printk indexing debugfs interface" 820 depends on PRINTK && DEBUG_FS 821 help 822 Add support for indexing of all printk formats known at compile time 823 at <debugfs>/printk/index/<module>. 824 825 This can be used as part of maintaining daemons which monitor 826 /dev/kmsg, as it permits auditing the printk formats present in a 827 kernel, allowing detection of cases where monitored printks are 828 changed or no longer present. 829 830 There is no additional runtime cost to printk with this enabled. 831 832# 833# Architectures with an unreliable sched_clock() should select this: 834# 835config HAVE_UNSTABLE_SCHED_CLOCK 836 bool 837 838config GENERIC_SCHED_CLOCK 839 bool 840 841menu "Scheduler features" 842 843config UCLAMP_TASK 844 bool "Enable utilization clamping for RT/FAIR tasks" 845 depends on CPU_FREQ_GOV_SCHEDUTIL 846 help 847 This feature enables the scheduler to track the clamped utilization 848 of each CPU based on RUNNABLE tasks scheduled on that CPU. 849 850 With this option, the user can specify the min and max CPU 851 utilization allowed for RUNNABLE tasks. The max utilization defines 852 the maximum frequency a task should use while the min utilization 853 defines the minimum frequency it should use. 854 855 Both min and max utilization clamp values are hints to the scheduler, 856 aiming at improving its frequency selection policy, but they do not 857 enforce or grant any specific bandwidth for tasks. 858 859 If in doubt, say N. 860 861config UCLAMP_BUCKETS_COUNT 862 int "Number of supported utilization clamp buckets" 863 range 5 20 864 default 5 865 depends on UCLAMP_TASK 866 help 867 Defines the number of clamp buckets to use. The range of each bucket 868 will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the 869 number of clamp buckets the finer their granularity and the higher 870 the precision of clamping aggregation and tracking at run-time. 871 872 For example, with the minimum configuration value we will have 5 873 clamp buckets tracking 20% utilization each. A 25% boosted tasks will 874 be refcounted in the [20..39]% bucket and will set the bucket clamp 875 effective value to 25%. 876 If a second 30% boosted task should be co-scheduled on the same CPU, 877 that task will be refcounted in the same bucket of the first task and 878 it will boost the bucket clamp effective value to 30%. 879 The clamp effective value of a bucket is reset to its nominal value 880 (20% in the example above) when there are no more tasks refcounted in 881 that bucket. 882 883 An additional boost/capping margin can be added to some tasks. In the 884 example above the 25% task will be boosted to 30% until it exits the 885 CPU. If that should be considered not acceptable on certain systems, 886 it's always possible to reduce the margin by increasing the number of 887 clamp buckets to trade off used memory for run-time tracking 888 precision. 889 890 If in doubt, use the default value. 891 892config SCHED_PROXY_EXEC 893 bool "Proxy Execution" 894 # Avoid some build failures w/ PREEMPT_RT until it can be fixed 895 depends on !PREEMPT_RT 896 # Need to investigate how to inform sched_ext of split contexts 897 depends on !SCHED_CLASS_EXT 898 # Not particularly useful until we get to multi-rq proxying 899 depends on EXPERT 900 help 901 This option enables proxy execution, a mechanism for mutex-owning 902 tasks to inherit the scheduling context of higher priority waiters. 903 904endmenu 905 906# 907# For architectures that want to enable the support for NUMA-affine scheduler 908# balancing logic: 909# 910config ARCH_SUPPORTS_NUMA_BALANCING 911 bool 912 913# 914# For architectures that prefer to flush all TLBs after a number of pages 915# are unmapped instead of sending one IPI per page to flush. The architecture 916# must provide guarantees on what happens if a clean TLB cache entry is 917# written after the unmap. Details are in mm/rmap.c near the check for 918# should_defer_flush. The architecture should also consider if the full flush 919# and the refill costs are offset by the savings of sending fewer IPIs. 920config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 921 bool 922 923config CC_HAS_INT128 924 def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT 925 926config CC_IMPLICIT_FALLTHROUGH 927 string 928 default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) 929 default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) 930 931# Currently, disable gcc-10+ array-bounds globally. 932# It's still broken in gcc-13, so no upper bound yet. 933config GCC10_NO_ARRAY_BOUNDS 934 def_bool y 935 936config CC_NO_ARRAY_BOUNDS 937 bool 938 default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC10_NO_ARRAY_BOUNDS 939 940# Currently, disable -Wstringop-overflow for GCC globally. 941config GCC_NO_STRINGOP_OVERFLOW 942 def_bool y 943 944config CC_NO_STRINGOP_OVERFLOW 945 bool 946 default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW 947 948config CC_STRINGOP_OVERFLOW 949 bool 950 default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW 951 952# 953# For architectures that know their GCC __int128 support is sound 954# 955config ARCH_SUPPORTS_INT128 956 bool 957 958# For architectures that (ab)use NUMA to represent different memory regions 959# all cpu-local but of different latencies, such as SuperH. 960# 961config ARCH_WANT_NUMA_VARIABLE_LOCALITY 962 bool 963 964config NUMA_BALANCING 965 bool "Memory placement aware NUMA scheduler" 966 depends on ARCH_SUPPORTS_NUMA_BALANCING 967 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY 968 depends on SMP && NUMA && MIGRATION && !PREEMPT_RT 969 help 970 This option adds support for automatic NUMA aware memory/task placement. 971 The mechanism is quite primitive and is based on migrating memory when 972 it has references to the node the task is running on. 973 974 This system will be inactive on UMA systems. 975 976config NUMA_BALANCING_DEFAULT_ENABLED 977 bool "Automatically enable NUMA aware memory/task placement" 978 default y 979 depends on NUMA_BALANCING 980 help 981 If set, automatic NUMA balancing will be enabled if running on a NUMA 982 machine. 983 984config SLAB_OBJ_EXT 985 bool 986 987menuconfig CGROUPS 988 bool "Control Group support" 989 select KERNFS 990 help 991 This option adds support for grouping sets of processes together, for 992 use with process control subsystems such as Cpusets, CFS, memory 993 controls or device isolation. 994 See 995 - Documentation/scheduler/sched-design-CFS.rst (CFS) 996 - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation 997 and resource control) 998 999 Say N if unsure. 1000 1001if CGROUPS 1002 1003config PAGE_COUNTER 1004 bool 1005 1006config CGROUP_FAVOR_DYNMODS 1007 bool "Favor dynamic modification latency reduction by default" 1008 help 1009 This option enables the "favordynmods" mount option by default 1010 which reduces the latencies of dynamic cgroup modifications such 1011 as task migrations and controller on/offs at the cost of making 1012 hot path operations such as forks and exits more expensive. 1013 1014 Say N if unsure. 1015 1016config MEMCG 1017 bool "Memory controller" 1018 select PAGE_COUNTER 1019 select EVENTFD 1020 select SLAB_OBJ_EXT 1021 select VM_EVENT_COUNTERS 1022 help 1023 Provides control over the memory footprint of tasks in a cgroup. 1024 1025config MEMCG_NMI_UNSAFE 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_NMI_SAFETY_REQUIRES_ATOMIC 1033 bool 1034 depends on MEMCG 1035 depends on HAVE_NMI 1036 depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && ARCH_HAVE_NMI_SAFE_CMPXCHG 1037 default y 1038 1039config MEMCG_V1 1040 bool "Legacy cgroup v1 memory controller" 1041 depends on MEMCG 1042 default n 1043 help 1044 Legacy cgroup v1 memory controller which has been deprecated by 1045 cgroup v2 implementation. The v1 is there for legacy applications 1046 which haven't migrated to the new cgroup v2 interface yet. If you 1047 do not have any such application then you are completely fine leaving 1048 this option disabled. 1049 1050 Please note that feature set of the legacy memory controller is likely 1051 going to shrink due to deprecation process. New deployments with v1 1052 controller are highly discouraged. 1053 1054 Say N if unsure. 1055 1056config BLK_CGROUP 1057 bool "IO controller" 1058 depends on BLOCK 1059 default n 1060 help 1061 Generic block IO controller cgroup interface. This is the common 1062 cgroup interface which should be used by various IO controlling 1063 policies. 1064 1065 Currently, CFQ IO scheduler uses it to recognize task groups and 1066 control disk bandwidth allocation (proportional time slice allocation) 1067 to such task groups. It is also used by bio throttling logic in 1068 block layer to implement upper limit in IO rates on a device. 1069 1070 This option only enables generic Block IO controller infrastructure. 1071 One needs to also enable actual IO controlling logic/policy. For 1072 enabling proportional weight division of disk bandwidth in CFQ, set 1073 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 1074 CONFIG_BLK_DEV_THROTTLING=y. 1075 1076 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information. 1077 1078config CGROUP_WRITEBACK 1079 bool 1080 depends on MEMCG && BLK_CGROUP 1081 default y 1082 1083menuconfig CGROUP_SCHED 1084 bool "CPU controller" 1085 default n 1086 help 1087 This feature lets CPU scheduler recognize task groups and control CPU 1088 bandwidth allocation to such task groups. It uses cgroups to group 1089 tasks. 1090 1091if CGROUP_SCHED 1092config GROUP_SCHED_WEIGHT 1093 def_bool n 1094 1095config GROUP_SCHED_BANDWIDTH 1096 def_bool n 1097 1098config FAIR_GROUP_SCHED 1099 bool "Group scheduling for SCHED_OTHER" 1100 depends on CGROUP_SCHED 1101 select GROUP_SCHED_WEIGHT 1102 default CGROUP_SCHED 1103 1104config CFS_BANDWIDTH 1105 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 1106 depends on FAIR_GROUP_SCHED 1107 select GROUP_SCHED_BANDWIDTH 1108 default n 1109 help 1110 This option allows users to define CPU bandwidth rates (limits) for 1111 tasks running within the fair group scheduler. Groups with no limit 1112 set are considered to be unconstrained and will run with no 1113 restriction. 1114 See Documentation/scheduler/sched-bwc.rst for more information. 1115 1116config RT_GROUP_SCHED 1117 bool "Group scheduling for SCHED_RR/FIFO" 1118 depends on CGROUP_SCHED 1119 default n 1120 help 1121 This feature lets you explicitly allocate real CPU bandwidth 1122 to task groups. If enabled, it will also make it impossible to 1123 schedule realtime tasks for non-root users until you allocate 1124 realtime bandwidth for them. 1125 See Documentation/scheduler/sched-rt-group.rst for more information. 1126 1127config RT_GROUP_SCHED_DEFAULT_DISABLED 1128 bool "Require boot parameter to enable group scheduling for SCHED_RR/FIFO" 1129 depends on RT_GROUP_SCHED 1130 default n 1131 help 1132 When set, the RT group scheduling is disabled by default. The option 1133 is in inverted form so that mere RT_GROUP_SCHED enables the group 1134 scheduling. 1135 1136 Say N if unsure. 1137 1138config EXT_GROUP_SCHED 1139 bool 1140 depends on SCHED_CLASS_EXT && CGROUP_SCHED 1141 select GROUP_SCHED_WEIGHT 1142 select GROUP_SCHED_BANDWIDTH 1143 default y 1144 1145endif #CGROUP_SCHED 1146 1147config SCHED_MM_CID 1148 def_bool y 1149 depends on SMP && RSEQ 1150 1151config UCLAMP_TASK_GROUP 1152 bool "Utilization clamping per group of tasks" 1153 depends on CGROUP_SCHED 1154 depends on UCLAMP_TASK 1155 default n 1156 help 1157 This feature enables the scheduler to track the clamped utilization 1158 of each CPU based on RUNNABLE tasks currently scheduled on that CPU. 1159 1160 When this option is enabled, the user can specify a min and max 1161 CPU bandwidth which is allowed for each single task in a group. 1162 The max bandwidth allows to clamp the maximum frequency a task 1163 can use, while the min bandwidth allows to define a minimum 1164 frequency a task will always use. 1165 1166 When task group based utilization clamping is enabled, an eventually 1167 specified task-specific clamp value is constrained by the cgroup 1168 specified clamp value. Both minimum and maximum task clamping cannot 1169 be bigger than the corresponding clamping defined at task group level. 1170 1171 If in doubt, say N. 1172 1173config CGROUP_PIDS 1174 bool "PIDs controller" 1175 help 1176 Provides enforcement of process number limits in the scope of a 1177 cgroup. Any attempt to fork more processes than is allowed in the 1178 cgroup will fail. PIDs are fundamentally a global resource because it 1179 is fairly trivial to reach PID exhaustion before you reach even a 1180 conservative kmemcg limit. As a result, it is possible to grind a 1181 system to halt without being limited by other cgroup policies. The 1182 PIDs controller is designed to stop this from happening. 1183 1184 It should be noted that organisational operations (such as attaching 1185 to a cgroup hierarchy) will *not* be blocked by the PIDs controller, 1186 since the PIDs limit only affects a process's ability to fork, not to 1187 attach to a cgroup. 1188 1189config CGROUP_RDMA 1190 bool "RDMA controller" 1191 help 1192 Provides enforcement of RDMA resources defined by IB stack. 1193 It is fairly easy for consumers to exhaust RDMA resources, which 1194 can result into resource unavailability to other consumers. 1195 RDMA controller is designed to stop this from happening. 1196 Attaching processes with active RDMA resources to the cgroup 1197 hierarchy is allowed even if can cross the hierarchy's limit. 1198 1199config CGROUP_DMEM 1200 bool "Device memory controller (DMEM)" 1201 select PAGE_COUNTER 1202 help 1203 The DMEM controller allows compatible devices to restrict device 1204 memory usage based on the cgroup hierarchy. 1205 1206 As an example, it allows you to restrict VRAM usage for applications 1207 in the DRM subsystem. 1208 1209config CGROUP_FREEZER 1210 bool "Freezer controller" 1211 help 1212 Provides a way to freeze and unfreeze all tasks in a 1213 cgroup. 1214 1215 This option affects the ORIGINAL cgroup interface. The cgroup2 memory 1216 controller includes important in-kernel memory consumers per default. 1217 1218 If you're using cgroup2, say N. 1219 1220config CGROUP_HUGETLB 1221 bool "HugeTLB controller" 1222 depends on HUGETLB_PAGE 1223 select PAGE_COUNTER 1224 default n 1225 help 1226 Provides a cgroup controller for HugeTLB pages. 1227 When you enable this, you can put a per cgroup limit on HugeTLB usage. 1228 The limit is enforced during page fault. Since HugeTLB doesn't 1229 support page reclaim, enforcing the limit at page fault time implies 1230 that, the application will get SIGBUS signal if it tries to access 1231 HugeTLB pages beyond its limit. This requires the application to know 1232 beforehand how much HugeTLB pages it would require for its use. The 1233 control group is tracked in the third page lru pointer. This means 1234 that we cannot use the controller with huge page less than 3 pages. 1235 1236config CPUSETS 1237 bool "Cpuset controller" 1238 depends on SMP 1239 select UNION_FIND 1240 help 1241 This option will let you create and manage CPUSETs which 1242 allow dynamically partitioning a system into sets of CPUs and 1243 Memory Nodes and assigning tasks to run only within those sets. 1244 This is primarily useful on large SMP or NUMA systems. 1245 1246 Say N if unsure. 1247 1248config CPUSETS_V1 1249 bool "Legacy cgroup v1 cpusets controller" 1250 depends on CPUSETS 1251 default n 1252 help 1253 Legacy cgroup v1 cpusets controller which has been deprecated by 1254 cgroup v2 implementation. The v1 is there for legacy applications 1255 which haven't migrated to the new cgroup v2 interface yet. Legacy 1256 interface includes cpuset filesystem and /proc/<pid>/cpuset. If you 1257 do not have any such application then you are completely fine leaving 1258 this option disabled. 1259 1260 Say N if unsure. 1261 1262config PROC_PID_CPUSET 1263 bool "Include legacy /proc/<pid>/cpuset file" 1264 depends on CPUSETS_V1 1265 default y 1266 1267config CGROUP_DEVICE 1268 bool "Device controller" 1269 help 1270 Provides a cgroup controller implementing whitelists for 1271 devices which a process in the cgroup can mknod or open. 1272 1273config CGROUP_CPUACCT 1274 bool "Simple CPU accounting controller" 1275 help 1276 Provides a simple controller for monitoring the 1277 total CPU consumed by the tasks in a cgroup. 1278 1279config CGROUP_PERF 1280 bool "Perf controller" 1281 depends on PERF_EVENTS 1282 help 1283 This option extends the perf per-cpu mode to restrict monitoring 1284 to threads which belong to the cgroup specified and run on the 1285 designated cpu. Or this can be used to have cgroup ID in samples 1286 so that it can monitor performance events among cgroups. 1287 1288 Say N if unsure. 1289 1290config CGROUP_BPF 1291 bool "Support for eBPF programs attached to cgroups" 1292 depends on BPF_SYSCALL 1293 select SOCK_CGROUP_DATA 1294 help 1295 Allow attaching eBPF programs to a cgroup using the bpf(2) 1296 syscall command BPF_PROG_ATTACH. 1297 1298 In which context these programs are accessed depends on the type 1299 of attachment. For instance, programs that are attached using 1300 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of 1301 inet sockets. 1302 1303config CGROUP_MISC 1304 bool "Misc resource controller" 1305 default n 1306 help 1307 Provides a controller for miscellaneous resources on a host. 1308 1309 Miscellaneous scalar resources are the resources on the host system 1310 which cannot be abstracted like the other cgroups. This controller 1311 tracks and limits the miscellaneous resources used by a process 1312 attached to a cgroup hierarchy. 1313 1314 For more information, please check misc cgroup section in 1315 /Documentation/admin-guide/cgroup-v2.rst. 1316 1317config CGROUP_DEBUG 1318 bool "Debug controller" 1319 default n 1320 depends on DEBUG_KERNEL 1321 help 1322 This option enables a simple controller that exports 1323 debugging information about the cgroups framework. This 1324 controller is for control cgroup debugging only. Its 1325 interfaces are not stable. 1326 1327 Say N. 1328 1329config SOCK_CGROUP_DATA 1330 bool 1331 default n 1332 1333endif # CGROUPS 1334 1335menuconfig NAMESPACES 1336 bool "Namespaces support" if EXPERT 1337 depends on MULTIUSER 1338 default !EXPERT 1339 help 1340 Provides the way to make tasks work with different objects using 1341 the same id. For example same IPC id may refer to different objects 1342 or same user id or pid may refer to different tasks when used in 1343 different namespaces. 1344 1345if NAMESPACES 1346 1347config UTS_NS 1348 bool "UTS namespace" 1349 default y 1350 help 1351 In this namespace tasks see different info provided with the 1352 uname() system call 1353 1354config TIME_NS 1355 bool "TIME namespace" 1356 depends on GENERIC_VDSO_TIME_NS 1357 default y 1358 help 1359 In this namespace boottime and monotonic clocks can be set. 1360 The time will keep going with the same pace. 1361 1362config IPC_NS 1363 bool "IPC namespace" 1364 depends on (SYSVIPC || POSIX_MQUEUE) 1365 default y 1366 help 1367 In this namespace tasks work with IPC ids which correspond to 1368 different IPC objects in different namespaces. 1369 1370config USER_NS 1371 bool "User namespace" 1372 default n 1373 help 1374 This allows containers, i.e. vservers, to use user namespaces 1375 to provide different user info for different servers. 1376 1377 When user namespaces are enabled in the kernel it is 1378 recommended that the MEMCG option also be enabled and that 1379 user-space use the memory control groups to limit the amount 1380 of memory a memory unprivileged users can use. 1381 1382 If unsure, say N. 1383 1384config PID_NS 1385 bool "PID Namespaces" 1386 default y 1387 help 1388 Support process id namespaces. This allows having multiple 1389 processes with the same pid as long as they are in different 1390 pid namespaces. This is a building block of containers. 1391 1392config NET_NS 1393 bool "Network namespace" 1394 depends on NET 1395 default y 1396 help 1397 Allow user space to create what appear to be multiple instances 1398 of the network stack. 1399 1400endif # NAMESPACES 1401 1402config CHECKPOINT_RESTORE 1403 bool "Checkpoint/restore support" 1404 depends on PROC_FS 1405 select PROC_CHILDREN 1406 select KCMP 1407 default n 1408 help 1409 Enables additional kernel features in a sake of checkpoint/restore. 1410 In particular it adds auxiliary prctl codes to setup process text, 1411 data and heap segment sizes, and a few additional /proc filesystem 1412 entries. 1413 1414 If unsure, say N here. 1415 1416config SCHED_AUTOGROUP 1417 bool "Automatic process group scheduling" 1418 select CGROUPS 1419 select CGROUP_SCHED 1420 select FAIR_GROUP_SCHED 1421 help 1422 This option optimizes the scheduler for common desktop workloads by 1423 automatically creating and populating task groups. This separation 1424 of workloads isolates aggressive CPU burners (like build jobs) from 1425 desktop applications. Task group autogeneration is currently based 1426 upon task session. 1427 1428config RELAY 1429 bool "Kernel->user space relay support (formerly relayfs)" 1430 select IRQ_WORK 1431 help 1432 This option enables support for relay interface support in 1433 certain file systems (such as debugfs). 1434 It is designed to provide an efficient mechanism for tools and 1435 facilities to relay large amounts of data from kernel space to 1436 user space. 1437 1438 If unsure, say N. 1439 1440config BLK_DEV_INITRD 1441 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1442 help 1443 The initial RAM filesystem is a ramfs which is loaded by the 1444 boot loader (loadlin or lilo) and that is mounted as root 1445 before the normal boot procedure. It is typically used to 1446 load modules needed to mount the "real" root file system, 1447 etc. See <file:Documentation/admin-guide/initrd.rst> for details. 1448 1449 If RAM disk support (BLK_DEV_RAM) is also included, this 1450 also enables initial RAM disk (initrd) support and adds 1451 15 Kbytes (more on some other architectures) to the kernel size. 1452 1453 If unsure say Y. 1454 1455if BLK_DEV_INITRD 1456 1457source "usr/Kconfig" 1458 1459endif 1460 1461config BOOT_CONFIG 1462 bool "Boot config support" 1463 select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED 1464 help 1465 Extra boot config allows system admin to pass a config file as 1466 complemental extension of kernel cmdline when booting. 1467 The boot config file must be attached at the end of initramfs 1468 with checksum, size and magic word. 1469 See <file:Documentation/admin-guide/bootconfig.rst> for details. 1470 1471 If unsure, say Y. 1472 1473config BOOT_CONFIG_FORCE 1474 bool "Force unconditional bootconfig processing" 1475 depends on BOOT_CONFIG 1476 default y if BOOT_CONFIG_EMBED 1477 help 1478 With this Kconfig option set, BOOT_CONFIG processing is carried 1479 out even when the "bootconfig" kernel-boot parameter is omitted. 1480 In fact, with this Kconfig option set, there is no way to 1481 make the kernel ignore the BOOT_CONFIG-supplied kernel-boot 1482 parameters. 1483 1484 If unsure, say N. 1485 1486config BOOT_CONFIG_EMBED 1487 bool "Embed bootconfig file in the kernel" 1488 depends on BOOT_CONFIG 1489 help 1490 Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the 1491 kernel. Usually, the bootconfig file is loaded with the initrd 1492 image. But if the system doesn't support initrd, this option will 1493 help you by embedding a bootconfig file while building the kernel. 1494 1495 If unsure, say N. 1496 1497config BOOT_CONFIG_EMBED_FILE 1498 string "Embedded bootconfig file path" 1499 depends on BOOT_CONFIG_EMBED 1500 help 1501 Specify a bootconfig file which will be embedded to the kernel. 1502 This bootconfig will be used if there is no initrd or no other 1503 bootconfig in the initrd. 1504 1505config INITRAMFS_PRESERVE_MTIME 1506 bool "Preserve cpio archive mtimes in initramfs" 1507 depends on BLK_DEV_INITRD 1508 default y 1509 help 1510 Each entry in an initramfs cpio archive carries an mtime value. When 1511 enabled, extracted cpio items take this mtime, with directory mtime 1512 setting deferred until after creation of any child entries. 1513 1514 If unsure, say Y. 1515 1516config INITRAMFS_TEST 1517 bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS 1518 depends on BLK_DEV_INITRD && KUNIT=y 1519 default KUNIT_ALL_TESTS 1520 help 1521 Build KUnit tests for initramfs. See Documentation/dev-tools/kunit 1522 1523choice 1524 prompt "Compiler optimization level" 1525 default CC_OPTIMIZE_FOR_PERFORMANCE 1526 1527config CC_OPTIMIZE_FOR_PERFORMANCE 1528 bool "Optimize for performance (-O2)" 1529 help 1530 This is the default optimization level for the kernel, building 1531 with the "-O2" compiler flag for best performance and most 1532 helpful compile-time warnings. 1533 1534config CC_OPTIMIZE_FOR_SIZE 1535 bool "Optimize for size (-Os)" 1536 help 1537 Choosing this option will pass "-Os" to your compiler resulting 1538 in a smaller kernel. 1539 1540endchoice 1541 1542config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1543 bool 1544 help 1545 This requires that the arch annotates or otherwise protects 1546 its external entry points from being discarded. Linker scripts 1547 must also merge .text.*, .data.*, and .bss.* correctly into 1548 output sections. Care must be taken not to pull in unrelated 1549 sections (e.g., '.text.init'). Typically '.' in section names 1550 is used to distinguish them from label names / C identifiers. 1551 1552config LD_DEAD_CODE_DATA_ELIMINATION 1553 bool "Dead code and data elimination (EXPERIMENTAL)" 1554 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1555 depends on EXPERT 1556 depends on $(cc-option,-ffunction-sections -fdata-sections) 1557 depends on $(ld-option,--gc-sections) 1558 help 1559 Enable this if you want to do dead code and data elimination with 1560 the linker by compiling with -ffunction-sections -fdata-sections, 1561 and linking with --gc-sections. 1562 1563 This can reduce on disk and in-memory size of the kernel 1564 code and static data, particularly for small configs and 1565 on small systems. This has the possibility of introducing 1566 silently broken kernel if the required annotations are not 1567 present. This option is not well tested yet, so use at your 1568 own risk. 1569 1570config LD_ORPHAN_WARN 1571 def_bool y 1572 depends on ARCH_WANT_LD_ORPHAN_WARN 1573 depends on $(ld-option,--orphan-handling=warn) 1574 depends on $(ld-option,--orphan-handling=error) 1575 1576config LD_ORPHAN_WARN_LEVEL 1577 string 1578 depends on LD_ORPHAN_WARN 1579 default "error" if WERROR 1580 default "warn" 1581 1582config SYSCTL 1583 bool 1584 1585config HAVE_UID16 1586 bool 1587 1588config SYSCTL_EXCEPTION_TRACE 1589 bool 1590 help 1591 Enable support for /proc/sys/debug/exception-trace. 1592 1593config SYSCTL_ARCH_UNALIGN_NO_WARN 1594 bool 1595 help 1596 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1597 Allows arch to define/use @no_unaligned_warning to possibly warn 1598 about unaligned access emulation going on under the hood. 1599 1600config SYSCTL_ARCH_UNALIGN_ALLOW 1601 bool 1602 help 1603 Enable support for /proc/sys/kernel/unaligned-trap 1604 Allows arches to define/use @unaligned_enabled to runtime toggle 1605 the unaligned access emulation. 1606 see arch/parisc/kernel/unaligned.c for reference 1607 1608config SYSFS_SYSCALL 1609 bool "Sysfs syscall support" 1610 default n 1611 help 1612 sys_sysfs is an obsolete system call no longer supported in libc. 1613 Note that disabling this option is more secure but might break 1614 compatibility with some systems. 1615 1616 If unsure say N here. 1617 1618config HAVE_PCSPKR_PLATFORM 1619 bool 1620 1621menuconfig EXPERT 1622 bool "Configure standard kernel features (expert users)" 1623 # Unhide debug options, to make the on-by-default options visible 1624 select DEBUG_KERNEL 1625 help 1626 This option allows certain base kernel options and settings 1627 to be disabled or tweaked. This is for specialized 1628 environments which can tolerate a "non-standard" kernel. 1629 Only use this if you really know what you are doing. 1630 1631config UID16 1632 bool "Enable 16-bit UID system calls" if EXPERT 1633 depends on HAVE_UID16 && MULTIUSER 1634 default y 1635 help 1636 This enables the legacy 16-bit UID syscall wrappers. 1637 1638config MULTIUSER 1639 bool "Multiple users, groups and capabilities support" if EXPERT 1640 default y 1641 help 1642 This option enables support for non-root users, groups and 1643 capabilities. 1644 1645 If you say N here, all processes will run with UID 0, GID 0, and all 1646 possible capabilities. Saying N here also compiles out support for 1647 system calls related to UIDs, GIDs, and capabilities, such as setuid, 1648 setgid, and capset. 1649 1650 If unsure, say Y here. 1651 1652config SGETMASK_SYSCALL 1653 bool "sgetmask/ssetmask syscalls support" if EXPERT 1654 default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH 1655 help 1656 sys_sgetmask and sys_ssetmask are obsolete system calls 1657 no longer supported in libc but still enabled by default in some 1658 architectures. 1659 1660 If unsure, leave the default option here. 1661 1662config FHANDLE 1663 bool "open by fhandle syscalls" if EXPERT 1664 select EXPORTFS 1665 default y 1666 help 1667 If you say Y here, a user level program will be able to map 1668 file names to handle and then later use the handle for 1669 different file system operations. This is useful in implementing 1670 userspace file servers, which now track files using handles instead 1671 of names. The handle would remain the same even if file names 1672 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 1673 syscalls. 1674 1675config POSIX_TIMERS 1676 bool "Posix Clocks & timers" if EXPERT 1677 default y 1678 help 1679 This includes native support for POSIX timers to the kernel. 1680 Some embedded systems have no use for them and therefore they 1681 can be configured out to reduce the size of the kernel image. 1682 1683 When this option is disabled, the following syscalls won't be 1684 available: timer_create, timer_gettime: timer_getoverrun, 1685 timer_settime, timer_delete, clock_adjtime, getitimer, 1686 setitimer, alarm. Furthermore, the clock_settime, clock_gettime, 1687 clock_getres and clock_nanosleep syscalls will be limited to 1688 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. 1689 1690 If unsure say y. 1691 1692config PRINTK 1693 default y 1694 bool "Enable support for printk" if EXPERT 1695 select IRQ_WORK 1696 help 1697 This option enables normal printk support. Removing it 1698 eliminates most of the message strings from the kernel image 1699 and makes the kernel more or less silent. As this makes it 1700 very difficult to diagnose system problems, saying N here is 1701 strongly discouraged. 1702 1703config BUG 1704 bool "BUG() support" if EXPERT 1705 default y 1706 help 1707 Disabling this option eliminates support for BUG and WARN, reducing 1708 the size of your kernel image and potentially quietly ignoring 1709 numerous fatal conditions. You should only consider disabling this 1710 option for embedded systems with no facilities for reporting errors. 1711 Just say Y. 1712 1713config ELF_CORE 1714 depends on COREDUMP 1715 default y 1716 bool "Enable ELF core dumps" if EXPERT 1717 help 1718 Enable support for generating core dumps. Disabling saves about 4k. 1719 1720 1721config PCSPKR_PLATFORM 1722 bool "Enable PC-Speaker support" if EXPERT 1723 depends on HAVE_PCSPKR_PLATFORM 1724 select I8253_LOCK 1725 default y 1726 help 1727 This option allows to disable the internal PC-Speaker 1728 support, saving some memory. 1729 1730config BASE_SMALL 1731 bool "Enable smaller-sized data structures for core" if EXPERT 1732 help 1733 Enabling this option reduces the size of miscellaneous core 1734 kernel data structures. This saves memory on small machines, 1735 but may reduce performance. 1736 1737config FUTEX 1738 bool "Enable futex support" if EXPERT 1739 depends on !(SPARC32 && SMP) 1740 default y 1741 imply RT_MUTEXES 1742 help 1743 Disabling this option will cause the kernel to be built without 1744 support for "fast userspace mutexes". The resulting kernel may not 1745 run glibc-based applications correctly. 1746 1747config FUTEX_PI 1748 bool 1749 depends on FUTEX && RT_MUTEXES 1750 default y 1751 1752config FUTEX_PRIVATE_HASH 1753 bool 1754 depends on FUTEX && !BASE_SMALL && MMU 1755 default y 1756 1757config FUTEX_MPOL 1758 bool 1759 depends on FUTEX && NUMA 1760 default y 1761 1762config EPOLL 1763 bool "Enable eventpoll support" if EXPERT 1764 default y 1765 help 1766 Disabling this option will cause the kernel to be built without 1767 support for epoll family of system calls. 1768 1769config SIGNALFD 1770 bool "Enable signalfd() system call" if EXPERT 1771 default y 1772 help 1773 Enable the signalfd() system call that allows to receive signals 1774 on a file descriptor. 1775 1776 If unsure, say Y. 1777 1778config TIMERFD 1779 bool "Enable timerfd() system call" if EXPERT 1780 default y 1781 help 1782 Enable the timerfd() system call that allows to receive timer 1783 events on a file descriptor. 1784 1785 If unsure, say Y. 1786 1787config EVENTFD 1788 bool "Enable eventfd() system call" if EXPERT 1789 default y 1790 help 1791 Enable the eventfd() system call that allows to receive both 1792 kernel notification (ie. KAIO) or userspace notifications. 1793 1794 If unsure, say Y. 1795 1796config SHMEM 1797 bool "Use full shmem filesystem" if EXPERT 1798 default y 1799 depends on MMU 1800 help 1801 The shmem is an internal filesystem used to manage shared memory. 1802 It is backed by swap and manages resource limits. It is also exported 1803 to userspace as tmpfs if TMPFS is enabled. Disabling this 1804 option replaces shmem and tmpfs with the much simpler ramfs code, 1805 which may be appropriate on small systems without swap. 1806 1807config AIO 1808 bool "Enable AIO support" if EXPERT 1809 default y 1810 help 1811 This option enables POSIX asynchronous I/O which may by used 1812 by some high performance threaded applications. Disabling 1813 this option saves about 7k. 1814 1815config IO_URING 1816 bool "Enable IO uring support" if EXPERT 1817 select IO_WQ 1818 default y 1819 help 1820 This option enables support for the io_uring interface, enabling 1821 applications to submit and complete IO through submission and 1822 completion rings that are shared between the kernel and application. 1823 1824config GCOV_PROFILE_URING 1825 bool "Enable GCOV profiling on the io_uring subsystem" 1826 depends on IO_URING && GCOV_KERNEL 1827 help 1828 Enable GCOV profiling on the io_uring subsystem, to facilitate 1829 code coverage testing. 1830 1831 If unsure, say N. 1832 1833 Note that this will have a negative impact on the performance of 1834 the io_uring subsystem, hence this should only be enabled for 1835 specific test purposes. 1836 1837config IO_URING_MOCK_FILE 1838 tristate "Enable io_uring mock files (Experimental)" if EXPERT 1839 default n 1840 depends on IO_URING 1841 help 1842 Enable mock files for io_uring subststem testing. The ABI might 1843 still change, so it's still experimental and should only be enabled 1844 for specific test purposes. 1845 1846 If unsure, say N. 1847 1848config ADVISE_SYSCALLS 1849 bool "Enable madvise/fadvise syscalls" if EXPERT 1850 default y 1851 help 1852 This option enables the madvise and fadvise syscalls, used by 1853 applications to advise the kernel about their future memory or file 1854 usage, improving performance. If building an embedded system where no 1855 applications use these syscalls, you can disable this option to save 1856 space. 1857 1858config MEMBARRIER 1859 bool "Enable membarrier() system call" if EXPERT 1860 default y 1861 help 1862 Enable the membarrier() system call that allows issuing memory 1863 barriers across all running threads, which can be used to distribute 1864 the cost of user-space memory barriers asymmetrically by transforming 1865 pairs of memory barriers into pairs consisting of membarrier() and a 1866 compiler barrier. 1867 1868 If unsure, say Y. 1869 1870config KCMP 1871 bool "Enable kcmp() system call" if EXPERT 1872 help 1873 Enable the kernel resource comparison system call. It provides 1874 user-space with the ability to compare two processes to see if they 1875 share a common resource, such as a file descriptor or even virtual 1876 memory space. 1877 1878 If unsure, say N. 1879 1880config RSEQ 1881 bool "Enable rseq() system call" if EXPERT 1882 default y 1883 depends on HAVE_RSEQ 1884 select MEMBARRIER 1885 help 1886 Enable the restartable sequences system call. It provides a 1887 user-space cache for the current CPU number value, which 1888 speeds up getting the current CPU number from user-space, 1889 as well as an ABI to speed up user-space operations on 1890 per-CPU data. 1891 1892 If unsure, say Y. 1893 1894config DEBUG_RSEQ 1895 default n 1896 bool "Enable debugging of rseq() system call" if EXPERT 1897 depends on RSEQ && DEBUG_KERNEL 1898 help 1899 Enable extra debugging checks for the rseq system call. 1900 1901 If unsure, say N. 1902 1903config CACHESTAT_SYSCALL 1904 bool "Enable cachestat() system call" if EXPERT 1905 default y 1906 help 1907 Enable the cachestat system call, which queries the page cache 1908 statistics of a file (number of cached pages, dirty pages, 1909 pages marked for writeback, (recently) evicted pages). 1910 1911 If unsure say Y here. 1912 1913config KALLSYMS 1914 bool "Load all symbols for debugging/ksymoops" if EXPERT 1915 default y 1916 help 1917 Say Y here to let the kernel print out symbolic crash information and 1918 symbolic stack backtraces. This increases the size of the kernel 1919 somewhat, as all symbols have to be loaded into the kernel image. 1920 1921config KALLSYMS_SELFTEST 1922 bool "Test the basic functions and performance of kallsyms" 1923 depends on KALLSYMS 1924 default n 1925 help 1926 Test the basic functions and performance of some interfaces, such as 1927 kallsyms_lookup_name. It also calculates the compression rate of the 1928 kallsyms compression algorithm for the current symbol set. 1929 1930 Start self-test automatically after system startup. Suggest executing 1931 "dmesg | grep kallsyms_selftest" to collect test results. "finish" is 1932 displayed in the last line, indicating that the test is complete. 1933 1934config KALLSYMS_ALL 1935 bool "Include all symbols in kallsyms" 1936 depends on DEBUG_KERNEL && KALLSYMS 1937 help 1938 Normally kallsyms only contains the symbols of functions for nicer 1939 OOPS messages and backtraces (i.e., symbols from the text and inittext 1940 sections). This is sufficient for most cases. And only if you want to 1941 enable kernel live patching, or other less common use cases (e.g., 1942 when a debugger is used) all symbols are required (i.e., names of 1943 variables from the data sections, etc). 1944 1945 This option makes sure that all symbols are loaded into the kernel 1946 image (i.e., symbols from all sections) in cost of increased kernel 1947 size (depending on the kernel configuration, it may be 300KiB or 1948 something like this). 1949 1950 Say N unless you really need all symbols, or kernel live patching. 1951 1952# end of the "standard kernel features (expert users)" menu 1953 1954config ARCH_HAS_MEMBARRIER_CALLBACKS 1955 bool 1956 1957config ARCH_HAS_MEMBARRIER_SYNC_CORE 1958 bool 1959 1960config ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 1961 bool 1962 help 1963 Control MSEAL_SYSTEM_MAPPINGS access based on architecture. 1964 1965 A 64-bit kernel is required for the memory sealing feature. 1966 No specific hardware features from the CPU are needed. 1967 1968 To enable this feature, the architecture needs to update their 1969 special mappings calls to include the sealing flag and confirm 1970 that it doesn't unmap/remap system mappings during the life 1971 time of the process. The existence of this flag for an architecture 1972 implies that it does not require the remapping of the system 1973 mappings during process lifetime, so sealing these mappings is safe 1974 from a kernel perspective. 1975 1976 After the architecture enables this, a distribution can set 1977 CONFIG_MSEAL_SYSTEM_MAPPING to manage access to the feature. 1978 1979 For complete descriptions of memory sealing, please see 1980 Documentation/userspace-api/mseal.rst 1981 1982config HAVE_PERF_EVENTS 1983 bool 1984 help 1985 See tools/perf/design.txt for details. 1986 1987config GUEST_PERF_EVENTS 1988 bool 1989 depends on HAVE_PERF_EVENTS 1990 1991config PERF_USE_VMALLOC 1992 bool 1993 help 1994 See tools/perf/design.txt for details 1995 1996menu "Kernel Performance Events And Counters" 1997 1998config PERF_EVENTS 1999 bool "Kernel performance events and counters" 2000 default y if PROFILING 2001 depends on HAVE_PERF_EVENTS 2002 select IRQ_WORK 2003 help 2004 Enable kernel support for various performance events provided 2005 by software and hardware. 2006 2007 Software events are supported either built-in or via the 2008 use of generic tracepoints. 2009 2010 Most modern CPUs support performance events via performance 2011 counter registers. These registers count the number of certain 2012 types of hw events: such as instructions executed, cachemisses 2013 suffered, or branches mis-predicted - without slowing down the 2014 kernel or applications. These registers can also trigger interrupts 2015 when a threshold number of events have passed - and can thus be 2016 used to profile the code that runs on that CPU. 2017 2018 The Linux Performance Event subsystem provides an abstraction of 2019 these software and hardware event capabilities, available via a 2020 system call and used by the "perf" utility in tools/perf/. It 2021 provides per task and per CPU counters, and it provides event 2022 capabilities on top of those. 2023 2024 Say Y if unsure. 2025 2026config DEBUG_PERF_USE_VMALLOC 2027 default n 2028 bool "Debug: use vmalloc to back perf mmap() buffers" 2029 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC 2030 select PERF_USE_VMALLOC 2031 help 2032 Use vmalloc memory to back perf mmap() buffers. 2033 2034 Mostly useful for debugging the vmalloc code on platforms 2035 that don't require it. 2036 2037 Say N if unsure. 2038 2039endmenu 2040 2041config SYSTEM_DATA_VERIFICATION 2042 def_bool n 2043 select SYSTEM_TRUSTED_KEYRING 2044 select KEYS 2045 select CRYPTO 2046 select CRYPTO_RSA 2047 select ASYMMETRIC_KEY_TYPE 2048 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 2049 select ASN1 2050 select OID_REGISTRY 2051 select X509_CERTIFICATE_PARSER 2052 select PKCS7_MESSAGE_PARSER 2053 help 2054 Provide PKCS#7 message verification using the contents of the system 2055 trusted keyring to provide public keys. This then can be used for 2056 module verification, kexec image verification and firmware blob 2057 verification. 2058 2059config PROFILING 2060 bool "Profiling support" 2061 help 2062 Say Y here to enable the extended profiling support mechanisms used 2063 by profilers. 2064 2065config RUST 2066 bool "Rust support" 2067 depends on HAVE_RUST 2068 depends on RUST_IS_AVAILABLE 2069 select EXTENDED_MODVERSIONS if MODVERSIONS 2070 depends on !MODVERSIONS || GENDWARFKSYMS 2071 depends on !GCC_PLUGIN_RANDSTRUCT 2072 depends on !RANDSTRUCT 2073 depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO) 2074 depends on !CFI_CLANG || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC 2075 select CFI_ICALL_NORMALIZE_INTEGERS if CFI_CLANG 2076 depends on !CALL_PADDING || RUSTC_VERSION >= 108100 2077 depends on !KASAN_SW_TAGS 2078 depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300 2079 help 2080 Enables Rust support in the kernel. 2081 2082 This allows other Rust-related options, like drivers written in Rust, 2083 to be selected. 2084 2085 It is also required to be able to load external kernel modules 2086 written in Rust. 2087 2088 See Documentation/rust/ for more information. 2089 2090 If unsure, say N. 2091 2092config RUSTC_VERSION_TEXT 2093 string 2094 depends on RUST 2095 default "$(RUSTC_VERSION_TEXT)" 2096 help 2097 See `CC_VERSION_TEXT`. 2098 2099config BINDGEN_VERSION_TEXT 2100 string 2101 depends on RUST 2102 # The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0 2103 # (https://github.com/rust-lang/rust-bindgen/pull/2678) and 0.71.0 2104 # (https://github.com/rust-lang/rust-bindgen/pull/3040). It can be removed 2105 # when the minimum version is upgraded past the latter (0.69.1 and 0.71.1 2106 # both fixed the issue). 2107 default "$(shell,$(BINDGEN) --version workaround-for-0.69.0 2>/dev/null)" 2108 2109# 2110# Place an empty function call at each tracepoint site. Can be 2111# dynamically changed for a probe function. 2112# 2113config TRACEPOINTS 2114 bool 2115 select TASKS_TRACE_RCU 2116 2117source "kernel/Kconfig.kexec" 2118 2119endmenu # General setup 2120 2121source "arch/Kconfig" 2122 2123config RT_MUTEXES 2124 bool 2125 default y if PREEMPT_RT 2126 2127config MODULE_SIG_FORMAT 2128 def_bool n 2129 select SYSTEM_DATA_VERIFICATION 2130 2131source "kernel/module/Kconfig" 2132 2133config INIT_ALL_POSSIBLE 2134 bool 2135 help 2136 Back when each arch used to define their own cpu_online_mask and 2137 cpu_possible_mask, some of them chose to initialize cpu_possible_mask 2138 with all 1s, and others with all 0s. When they were centralised, 2139 it was better to provide this option than to break all the archs 2140 and have several arch maintainers pursuing me down dark alleys. 2141 2142source "block/Kconfig" 2143 2144config PREEMPT_NOTIFIERS 2145 bool 2146 2147config PADATA 2148 depends on SMP 2149 bool 2150 2151config ASN1 2152 tristate 2153 help 2154 Build a simple ASN.1 grammar compiler that produces a bytecode output 2155 that can be interpreted by the ASN.1 stream decoder and used to 2156 inform it as to what tags are to be expected in a stream and what 2157 functions to call on what tags. 2158 2159source "kernel/Kconfig.locks" 2160 2161config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 2162 bool 2163 2164config ARCH_HAS_PREPARE_SYNC_CORE_CMD 2165 bool 2166 2167config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2168 bool 2169 2170# It may be useful for an architecture to override the definitions of the 2171# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> 2172# and the COMPAT_ variants in <linux/compat.h>, in particular to use a 2173# different calling convention for syscalls. They can also override the 2174# macros for not-implemented syscalls in kernel/sys_ni.c and 2175# kernel/time/posix-stubs.c. All these overrides need to be available in 2176# <asm/syscall_wrapper.h>. 2177config ARCH_HAS_SYSCALL_WRAPPER 2178 def_bool n 2179