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 RUSTC_HAS_COERCE_POINTEE 133 def_bool RUSTC_VERSION >= 108400 134 135config PAHOLE_VERSION 136 int 137 default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE)) 138 139config CONSTRUCTORS 140 bool 141 142config IRQ_WORK 143 def_bool y if SMP 144 145config BUILDTIME_TABLE_SORT 146 bool 147 148config THREAD_INFO_IN_TASK 149 bool 150 help 151 Select this to move thread_info off the stack into task_struct. To 152 make this work, an arch will need to remove all thread_info fields 153 except flags and fix any runtime bugs. 154 155 One subtle change that will be needed is to use try_get_task_stack() 156 and put_task_stack() in save_thread_stack_tsk() and get_wchan(). 157 158menu "General setup" 159 160config BROKEN 161 bool 162 163config BROKEN_ON_SMP 164 bool 165 depends on BROKEN || !SMP 166 default y 167 168config INIT_ENV_ARG_LIMIT 169 int 170 default 32 if !UML 171 default 128 if UML 172 help 173 Maximum of each of the number of arguments and environment 174 variables passed to init from the kernel command line. 175 176config COMPILE_TEST 177 bool "Compile also drivers which will not load" 178 depends on HAS_IOMEM 179 help 180 Some drivers can be compiled on a different platform than they are 181 intended to be run on. Despite they cannot be loaded there (or even 182 when they load they cannot be used due to missing HW support), 183 developers still, opposing to distributors, might want to build such 184 drivers to compile-test them. 185 186 If you are a developer and want to build everything available, say Y 187 here. If you are a user/distributor, say N here to exclude useless 188 drivers to be distributed. 189 190config WERROR 191 bool "Compile the kernel with warnings as errors" 192 default COMPILE_TEST 193 help 194 A kernel build should not cause any compiler warnings, and this 195 enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags 196 to enforce that rule by default. Certain warnings from other tools 197 such as the linker may be upgraded to errors with this option as 198 well. 199 200 However, if you have a new (or very old) compiler or linker with odd 201 and unusual warnings, or you have some architecture with problems, 202 you may need to disable this config option in order to 203 successfully build the kernel. 204 205 If in doubt, say Y. 206 207config UAPI_HEADER_TEST 208 bool "Compile test UAPI headers" 209 depends on HEADERS_INSTALL && CC_CAN_LINK 210 help 211 Compile test headers exported to user-space to ensure they are 212 self-contained, i.e. compilable as standalone units. 213 214 If you are a developer or tester and want to ensure the exported 215 headers are self-contained, say Y here. Otherwise, choose N. 216 217config LOCALVERSION 218 string "Local version - append to kernel release" 219 help 220 Append an extra string to the end of your kernel version. 221 This will show up when you type uname, for example. 222 The string you set here will be appended after the contents of 223 any files with a filename matching localversion* in your 224 object and source tree, in that order. Your total string can 225 be a maximum of 64 characters. 226 227config LOCALVERSION_AUTO 228 bool "Automatically append version information to the version string" 229 default y 230 depends on !COMPILE_TEST 231 help 232 This will try to automatically determine if the current tree is a 233 release tree by looking for git tags that belong to the current 234 top of tree revision. 235 236 A string of the format -gxxxxxxxx will be added to the localversion 237 if a git-based tree is found. The string generated by this will be 238 appended after any matching localversion* files, and after the value 239 set in CONFIG_LOCALVERSION. 240 241 (The actual string used here is the first 12 characters produced 242 by running the command: 243 244 $ git rev-parse --verify HEAD 245 246 which is done within the script "scripts/setlocalversion".) 247 248config BUILD_SALT 249 string "Build ID Salt" 250 default "" 251 help 252 The build ID is used to link binaries and their debug info. Setting 253 this option will use the value in the calculation of the build id. 254 This is mostly useful for distributions which want to ensure the 255 build is unique between builds. It's safe to leave the default. 256 257config HAVE_KERNEL_GZIP 258 bool 259 260config HAVE_KERNEL_BZIP2 261 bool 262 263config HAVE_KERNEL_LZMA 264 bool 265 266config HAVE_KERNEL_XZ 267 bool 268 269config HAVE_KERNEL_LZO 270 bool 271 272config HAVE_KERNEL_LZ4 273 bool 274 275config HAVE_KERNEL_ZSTD 276 bool 277 278config HAVE_KERNEL_UNCOMPRESSED 279 bool 280 281choice 282 prompt "Kernel compression mode" 283 default KERNEL_GZIP 284 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 285 help 286 The linux kernel is a kind of self-extracting executable. 287 Several compression algorithms are available, which differ 288 in efficiency, compression and decompression speed. 289 Compression speed is only relevant when building a kernel. 290 Decompression speed is relevant at each boot. 291 292 If you have any problems with bzip2 or lzma compressed 293 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 294 version of this functionality (bzip2 only), for 2.4, was 295 supplied by Christian Ludwig) 296 297 High compression options are mostly useful for users, who 298 are low on disk space (embedded systems), but for whom ram 299 size matters less. 300 301 If in doubt, select 'gzip' 302 303config KERNEL_GZIP 304 bool "Gzip" 305 depends on HAVE_KERNEL_GZIP 306 help 307 The old and tried gzip compression. It provides a good balance 308 between compression ratio and decompression speed. 309 310config KERNEL_BZIP2 311 bool "Bzip2" 312 depends on HAVE_KERNEL_BZIP2 313 help 314 Its compression ratio and speed is intermediate. 315 Decompression speed is slowest among the choices. The kernel 316 size is about 10% smaller with bzip2, in comparison to gzip. 317 Bzip2 uses a large amount of memory. For modern kernels you 318 will need at least 8MB RAM or more for booting. 319 320config KERNEL_LZMA 321 bool "LZMA" 322 depends on HAVE_KERNEL_LZMA 323 help 324 This compression algorithm's ratio is best. Decompression speed 325 is between gzip and bzip2. Compression is slowest. 326 The kernel size is about 33% smaller with LZMA in comparison to gzip. 327 328config KERNEL_XZ 329 bool "XZ" 330 depends on HAVE_KERNEL_XZ 331 help 332 XZ uses the LZMA2 algorithm and instruction set specific 333 BCJ filters which can improve compression ratio of executable 334 code. The size of the kernel is about 30% smaller with XZ in 335 comparison to gzip. On architectures for which there is a BCJ 336 filter (i386, x86_64, ARM, ARM64, RISC-V, big endian PowerPC, 337 and SPARC), XZ will create a few percent smaller kernel than 338 plain LZMA. 339 340 The speed is about the same as with LZMA: The decompression 341 speed of XZ is better than that of bzip2 but worse than gzip 342 and LZO. Compression is slow. 343 344config KERNEL_LZO 345 bool "LZO" 346 depends on HAVE_KERNEL_LZO 347 help 348 Its compression ratio is the poorest among the choices. The kernel 349 size is about 10% bigger than gzip; however its speed 350 (both compression and decompression) is the fastest. 351 352config KERNEL_LZ4 353 bool "LZ4" 354 depends on HAVE_KERNEL_LZ4 355 help 356 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. 357 A preliminary version of LZ4 de/compression tool is available at 358 <https://code.google.com/p/lz4/>. 359 360 Its compression ratio is worse than LZO. The size of the kernel 361 is about 8% bigger than LZO. But the decompression speed is 362 faster than LZO. 363 364config KERNEL_ZSTD 365 bool "ZSTD" 366 depends on HAVE_KERNEL_ZSTD 367 help 368 ZSTD is a compression algorithm targeting intermediate compression 369 with fast decompression speed. It will compress better than GZIP and 370 decompress around the same speed as LZO, but slower than LZ4. You 371 will need at least 192 KB RAM or more for booting. The zstd command 372 line tool is required for compression. 373 374config KERNEL_UNCOMPRESSED 375 bool "None" 376 depends on HAVE_KERNEL_UNCOMPRESSED 377 help 378 Produce uncompressed kernel image. This option is usually not what 379 you want. It is useful for debugging the kernel in slow simulation 380 environments, where decompressing and moving the kernel is awfully 381 slow. This option allows early boot code to skip the decompressor 382 and jump right at uncompressed kernel image. 383 384endchoice 385 386config DEFAULT_INIT 387 string "Default init path" 388 default "" 389 help 390 This option determines the default init for the system if no init= 391 option is passed on the kernel command line. If the requested path is 392 not present, we will still then move on to attempting further 393 locations (e.g. /sbin/init, etc). If this is empty, we will just use 394 the fallback list when init= is not passed. 395 396config DEFAULT_HOSTNAME 397 string "Default hostname" 398 default "(none)" 399 help 400 This option determines the default system hostname before userspace 401 calls sethostname(2). The kernel traditionally uses "(none)" here, 402 but you may wish to use a different default here to make a minimal 403 system more usable with less configuration. 404 405config SYSVIPC 406 bool "System V IPC" 407 help 408 Inter Process Communication is a suite of library functions and 409 system calls which let processes (running programs) synchronize and 410 exchange information. It is generally considered to be a good thing, 411 and some programs won't run unless you say Y here. In particular, if 412 you want to run the DOS emulator dosemu under Linux (read the 413 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 414 you'll need to say Y here. 415 416 You can find documentation about IPC with "info ipc" and also in 417 section 6.4 of the Linux Programmer's Guide, available from 418 <http://www.tldp.org/guides.html>. 419 420config SYSVIPC_SYSCTL 421 bool 422 depends on SYSVIPC 423 depends on SYSCTL 424 default y 425 426config SYSVIPC_COMPAT 427 def_bool y 428 depends on COMPAT && SYSVIPC 429 430config POSIX_MQUEUE 431 bool "POSIX Message Queues" 432 depends on NET 433 help 434 POSIX variant of message queues is a part of IPC. In POSIX message 435 queues every message has a priority which decides about succession 436 of receiving it by a process. If you want to compile and run 437 programs written e.g. for Solaris with use of its POSIX message 438 queues (functions mq_*) say Y here. 439 440 POSIX message queues are visible as a filesystem called 'mqueue' 441 and can be mounted somewhere if you want to do filesystem 442 operations on message queues. 443 444 If unsure, say Y. 445 446config POSIX_MQUEUE_SYSCTL 447 bool 448 depends on POSIX_MQUEUE 449 depends on SYSCTL 450 default y 451 452config WATCH_QUEUE 453 bool "General notification queue" 454 default n 455 help 456 457 This is a general notification queue for the kernel to pass events to 458 userspace by splicing them into pipes. It can be used in conjunction 459 with watches for key/keyring change notifications and device 460 notifications. 461 462 See Documentation/core-api/watch_queue.rst 463 464config CROSS_MEMORY_ATTACH 465 bool "Enable process_vm_readv/writev syscalls" 466 depends on MMU 467 default y 468 help 469 Enabling this option adds the system calls process_vm_readv and 470 process_vm_writev which allow a process with the correct privileges 471 to directly read from or write to another process' address space. 472 See the man page for more details. 473 474config USELIB 475 bool "uselib syscall (for libc5 and earlier)" 476 default ALPHA || M68K || SPARC 477 help 478 This option enables the uselib syscall, a system call used in the 479 dynamic linker from libc5 and earlier. glibc does not use this 480 system call. If you intend to run programs built on libc5 or 481 earlier, you may need to enable this syscall. Current systems 482 running glibc can safely disable this. 483 484config AUDIT 485 bool "Auditing support" 486 depends on NET 487 help 488 Enable auditing infrastructure that can be used with another 489 kernel subsystem, such as SELinux (which requires this for 490 logging of avc messages output). System call auditing is included 491 on architectures which support it. 492 493config HAVE_ARCH_AUDITSYSCALL 494 bool 495 496config AUDITSYSCALL 497 def_bool y 498 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL 499 select FSNOTIFY 500 501source "kernel/irq/Kconfig" 502source "kernel/time/Kconfig" 503source "kernel/bpf/Kconfig" 504source "kernel/Kconfig.preempt" 505 506menu "CPU/Task time and stats accounting" 507 508config VIRT_CPU_ACCOUNTING 509 bool 510 511choice 512 prompt "Cputime accounting" 513 default TICK_CPU_ACCOUNTING 514 515# Kind of a stub config for the pure tick based cputime accounting 516config TICK_CPU_ACCOUNTING 517 bool "Simple tick based cputime accounting" 518 depends on !S390 && !NO_HZ_FULL 519 help 520 This is the basic tick based cputime accounting that maintains 521 statistics about user, system and idle time spent on per jiffies 522 granularity. 523 524 If unsure, say Y. 525 526config VIRT_CPU_ACCOUNTING_NATIVE 527 bool "Deterministic task and CPU time accounting" 528 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL 529 select VIRT_CPU_ACCOUNTING 530 help 531 Select this option to enable more accurate task and CPU time 532 accounting. This is done by reading a CPU counter on each 533 kernel entry and exit and on transitions within the kernel 534 between system, softirq and hardirq state, so there is a 535 small performance impact. In the case of s390 or IBM POWER > 5, 536 this also enables accounting of stolen time on logically-partitioned 537 systems. 538 539config VIRT_CPU_ACCOUNTING_GEN 540 bool "Full dynticks CPU time accounting" 541 depends on HAVE_CONTEXT_TRACKING_USER 542 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN 543 depends on GENERIC_CLOCKEVENTS 544 select VIRT_CPU_ACCOUNTING 545 select CONTEXT_TRACKING_USER 546 help 547 Select this option to enable task and CPU time accounting on full 548 dynticks systems. This accounting is implemented by watching every 549 kernel-user boundaries using the context tracking subsystem. 550 The accounting is thus performed at the expense of some significant 551 overhead. 552 553 For now this is only useful if you are working on the full 554 dynticks subsystem development. 555 556 If unsure, say N. 557 558endchoice 559 560config IRQ_TIME_ACCOUNTING 561 bool "Fine granularity task level IRQ time accounting" 562 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE 563 help 564 Select this option to enable fine granularity task irq time 565 accounting. This is done by reading a timestamp on each 566 transitions between softirq and hardirq state, so there can be a 567 small performance impact. 568 569 If in doubt, say N here. 570 571config HAVE_SCHED_AVG_IRQ 572 def_bool y 573 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING 574 depends on SMP 575 576config SCHED_HW_PRESSURE 577 bool 578 default y if ARM && ARM_CPU_TOPOLOGY 579 default y if ARM64 580 depends on SMP 581 depends on CPU_FREQ_THERMAL 582 help 583 Select this option to enable HW pressure accounting in the 584 scheduler. HW pressure is the value conveyed to the scheduler 585 that reflects the reduction in CPU compute capacity resulted from 586 HW throttling. HW throttling occurs when the performance of 587 a CPU is capped due to high operating temperatures as an example. 588 589 If selected, the scheduler will be able to balance tasks accordingly, 590 i.e. put less load on throttled CPUs than on non/less throttled ones. 591 592 This requires the architecture to implement 593 arch_update_hw_pressure() and arch_scale_thermal_pressure(). 594 595config BSD_PROCESS_ACCT 596 bool "BSD Process Accounting" 597 depends on MULTIUSER 598 help 599 If you say Y here, a user level program will be able to instruct the 600 kernel (via a special system call) to write process accounting 601 information to a file: whenever a process exits, information about 602 that process will be appended to the file by the kernel. The 603 information includes things such as creation time, owning user, 604 command name, memory usage, controlling terminal etc. (the complete 605 list is in the struct acct in <file:include/linux/acct.h>). It is 606 up to the user level program to do useful things with this 607 information. This is generally a good idea, so say Y. 608 609config BSD_PROCESS_ACCT_V3 610 bool "BSD Process Accounting version 3 file format" 611 depends on BSD_PROCESS_ACCT 612 default n 613 help 614 If you say Y here, the process accounting information is written 615 in a new file format that also logs the process IDs of each 616 process and its parent. Note that this file format is incompatible 617 with previous v0/v1/v2 file formats, so you will need updated tools 618 for processing it. A preliminary version of these tools is available 619 at <http://www.gnu.org/software/acct/>. 620 621config TASKSTATS 622 bool "Export task/process statistics through netlink" 623 depends on NET 624 depends on MULTIUSER 625 default n 626 help 627 Export selected statistics for tasks/processes through the 628 generic netlink interface. Unlike BSD process accounting, the 629 statistics are available during the lifetime of tasks/processes as 630 responses to commands. Like BSD accounting, they are sent to user 631 space on task exit. 632 633 Say N if unsure. 634 635config TASK_DELAY_ACCT 636 bool "Enable per-task delay accounting" 637 depends on TASKSTATS 638 select SCHED_INFO 639 help 640 Collect information on time spent by a task waiting for system 641 resources like cpu, synchronous block I/O completion and swapping 642 in pages. Such statistics can help in setting a task's priorities 643 relative to other tasks for cpu, io, rss limits etc. 644 645 Say N if unsure. 646 647config TASK_XACCT 648 bool "Enable extended accounting over taskstats" 649 depends on TASKSTATS 650 help 651 Collect extended task accounting data and send the data 652 to userland for processing over the taskstats interface. 653 654 Say N if unsure. 655 656config TASK_IO_ACCOUNTING 657 bool "Enable per-task storage I/O accounting" 658 depends on TASK_XACCT 659 help 660 Collect information on the number of bytes of storage I/O which this 661 task has caused. 662 663 Say N if unsure. 664 665config PSI 666 bool "Pressure stall information tracking" 667 select KERNFS 668 help 669 Collect metrics that indicate how overcommitted the CPU, memory, 670 and IO capacity are in the system. 671 672 If you say Y here, the kernel will create /proc/pressure/ with the 673 pressure statistics files cpu, memory, and io. These will indicate 674 the share of walltime in which some or all tasks in the system are 675 delayed due to contention of the respective resource. 676 677 In kernels with cgroup support, cgroups (cgroup2 only) will 678 have cpu.pressure, memory.pressure, and io.pressure files, 679 which aggregate pressure stalls for the grouped tasks only. 680 681 For more details see Documentation/accounting/psi.rst. 682 683 Say N if unsure. 684 685config PSI_DEFAULT_DISABLED 686 bool "Require boot parameter to enable pressure stall information tracking" 687 default n 688 depends on PSI 689 help 690 If set, pressure stall information tracking will be disabled 691 per default but can be enabled through passing psi=1 on the 692 kernel commandline during boot. 693 694 This feature adds some code to the task wakeup and sleep 695 paths of the scheduler. The overhead is too low to affect 696 common scheduling-intense workloads in practice (such as 697 webservers, memcache), but it does show up in artificial 698 scheduler stress tests, such as hackbench. 699 700 If you are paranoid and not sure what the kernel will be 701 used for, say Y. 702 703 Say N if unsure. 704 705endmenu # "CPU/Task time and stats accounting" 706 707config CPU_ISOLATION 708 bool "CPU isolation" 709 depends on SMP || COMPILE_TEST 710 default y 711 help 712 Make sure that CPUs running critical tasks are not disturbed by 713 any source of "noise" such as unbound workqueues, timers, kthreads... 714 Unbound jobs get offloaded to housekeeping CPUs. This is driven by 715 the "isolcpus=" boot parameter. 716 717 Say Y if unsure. 718 719source "kernel/rcu/Kconfig" 720 721config IKCONFIG 722 tristate "Kernel .config support" 723 help 724 This option enables the complete Linux kernel ".config" file 725 contents to be saved in the kernel. It provides documentation 726 of which kernel options are used in a running kernel or in an 727 on-disk kernel. This information can be extracted from the kernel 728 image file with the script scripts/extract-ikconfig and used as 729 input to rebuild the current kernel or to build another kernel. 730 It can also be extracted from a running kernel by reading 731 /proc/config.gz if enabled (below). 732 733config IKCONFIG_PROC 734 bool "Enable access to .config through /proc/config.gz" 735 depends on IKCONFIG && PROC_FS 736 help 737 This option enables access to the kernel configuration file 738 through /proc/config.gz. 739 740config IKHEADERS 741 tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz" 742 depends on SYSFS 743 help 744 This option enables access to the in-kernel headers that are generated during 745 the build process. These can be used to build eBPF tracing programs, 746 or similar programs. If you build the headers as a module, a module called 747 kheaders.ko is built which can be loaded on-demand to get access to headers. 748 749config LOG_BUF_SHIFT 750 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 751 range 12 25 752 default 17 753 depends on PRINTK 754 help 755 Select the minimal kernel log buffer size as a power of 2. 756 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config 757 parameter, see below. Any higher size also might be forced 758 by "log_buf_len" boot parameter. 759 760 Examples: 761 17 => 128 KB 762 16 => 64 KB 763 15 => 32 KB 764 14 => 16 KB 765 13 => 8 KB 766 12 => 4 KB 767 768config LOG_CPU_MAX_BUF_SHIFT 769 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" 770 depends on SMP 771 range 0 21 772 default 0 if BASE_SMALL 773 default 12 774 depends on PRINTK 775 help 776 This option allows to increase the default ring buffer size 777 according to the number of CPUs. The value defines the contribution 778 of each CPU as a power of 2. The used space is typically only few 779 lines however it might be much more when problems are reported, 780 e.g. backtraces. 781 782 The increased size means that a new buffer has to be allocated and 783 the original static one is unused. It makes sense only on systems 784 with more CPUs. Therefore this value is used only when the sum of 785 contributions is greater than the half of the default kernel ring 786 buffer as defined by LOG_BUF_SHIFT. The default values are set 787 so that more than 16 CPUs are needed to trigger the allocation. 788 789 Also this option is ignored when "log_buf_len" kernel parameter is 790 used as it forces an exact (power of two) size of the ring buffer. 791 792 The number of possible CPUs is used for this computation ignoring 793 hotplugging making the computation optimal for the worst case 794 scenario while allowing a simple algorithm to be used from bootup. 795 796 Examples shift values and their meaning: 797 17 => 128 KB for each CPU 798 16 => 64 KB for each CPU 799 15 => 32 KB for each CPU 800 14 => 16 KB for each CPU 801 13 => 8 KB for each CPU 802 12 => 4 KB for each CPU 803 804config PRINTK_INDEX 805 bool "Printk indexing debugfs interface" 806 depends on PRINTK && DEBUG_FS 807 help 808 Add support for indexing of all printk formats known at compile time 809 at <debugfs>/printk/index/<module>. 810 811 This can be used as part of maintaining daemons which monitor 812 /dev/kmsg, as it permits auditing the printk formats present in a 813 kernel, allowing detection of cases where monitored printks are 814 changed or no longer present. 815 816 There is no additional runtime cost to printk with this enabled. 817 818# 819# Architectures with an unreliable sched_clock() should select this: 820# 821config HAVE_UNSTABLE_SCHED_CLOCK 822 bool 823 824config GENERIC_SCHED_CLOCK 825 bool 826 827menu "Scheduler features" 828 829config UCLAMP_TASK 830 bool "Enable utilization clamping for RT/FAIR tasks" 831 depends on CPU_FREQ_GOV_SCHEDUTIL 832 help 833 This feature enables the scheduler to track the clamped utilization 834 of each CPU based on RUNNABLE tasks scheduled on that CPU. 835 836 With this option, the user can specify the min and max CPU 837 utilization allowed for RUNNABLE tasks. The max utilization defines 838 the maximum frequency a task should use while the min utilization 839 defines the minimum frequency it should use. 840 841 Both min and max utilization clamp values are hints to the scheduler, 842 aiming at improving its frequency selection policy, but they do not 843 enforce or grant any specific bandwidth for tasks. 844 845 If in doubt, say N. 846 847config UCLAMP_BUCKETS_COUNT 848 int "Number of supported utilization clamp buckets" 849 range 5 20 850 default 5 851 depends on UCLAMP_TASK 852 help 853 Defines the number of clamp buckets to use. The range of each bucket 854 will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the 855 number of clamp buckets the finer their granularity and the higher 856 the precision of clamping aggregation and tracking at run-time. 857 858 For example, with the minimum configuration value we will have 5 859 clamp buckets tracking 20% utilization each. A 25% boosted tasks will 860 be refcounted in the [20..39]% bucket and will set the bucket clamp 861 effective value to 25%. 862 If a second 30% boosted task should be co-scheduled on the same CPU, 863 that task will be refcounted in the same bucket of the first task and 864 it will boost the bucket clamp effective value to 30%. 865 The clamp effective value of a bucket is reset to its nominal value 866 (20% in the example above) when there are no more tasks refcounted in 867 that bucket. 868 869 An additional boost/capping margin can be added to some tasks. In the 870 example above the 25% task will be boosted to 30% until it exits the 871 CPU. If that should be considered not acceptable on certain systems, 872 it's always possible to reduce the margin by increasing the number of 873 clamp buckets to trade off used memory for run-time tracking 874 precision. 875 876 If in doubt, use the default value. 877 878endmenu 879 880# 881# For architectures that want to enable the support for NUMA-affine scheduler 882# balancing logic: 883# 884config ARCH_SUPPORTS_NUMA_BALANCING 885 bool 886 887# 888# For architectures that prefer to flush all TLBs after a number of pages 889# are unmapped instead of sending one IPI per page to flush. The architecture 890# must provide guarantees on what happens if a clean TLB cache entry is 891# written after the unmap. Details are in mm/rmap.c near the check for 892# should_defer_flush. The architecture should also consider if the full flush 893# and the refill costs are offset by the savings of sending fewer IPIs. 894config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 895 bool 896 897config CC_HAS_INT128 898 def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT 899 900config CC_IMPLICIT_FALLTHROUGH 901 string 902 default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) 903 default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) 904 905# Currently, disable gcc-10+ array-bounds globally. 906# It's still broken in gcc-13, so no upper bound yet. 907config GCC10_NO_ARRAY_BOUNDS 908 def_bool y 909 910config CC_NO_ARRAY_BOUNDS 911 bool 912 default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC10_NO_ARRAY_BOUNDS 913 914# Currently, disable -Wstringop-overflow for GCC globally. 915config GCC_NO_STRINGOP_OVERFLOW 916 def_bool y 917 918config CC_NO_STRINGOP_OVERFLOW 919 bool 920 default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW 921 922config CC_STRINGOP_OVERFLOW 923 bool 924 default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW 925 926# 927# For architectures that know their GCC __int128 support is sound 928# 929config ARCH_SUPPORTS_INT128 930 bool 931 932# For architectures that (ab)use NUMA to represent different memory regions 933# all cpu-local but of different latencies, such as SuperH. 934# 935config ARCH_WANT_NUMA_VARIABLE_LOCALITY 936 bool 937 938config NUMA_BALANCING 939 bool "Memory placement aware NUMA scheduler" 940 depends on ARCH_SUPPORTS_NUMA_BALANCING 941 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY 942 depends on SMP && NUMA && MIGRATION && !PREEMPT_RT 943 help 944 This option adds support for automatic NUMA aware memory/task placement. 945 The mechanism is quite primitive and is based on migrating memory when 946 it has references to the node the task is running on. 947 948 This system will be inactive on UMA systems. 949 950config NUMA_BALANCING_DEFAULT_ENABLED 951 bool "Automatically enable NUMA aware memory/task placement" 952 default y 953 depends on NUMA_BALANCING 954 help 955 If set, automatic NUMA balancing will be enabled if running on a NUMA 956 machine. 957 958config SLAB_OBJ_EXT 959 bool 960 961menuconfig CGROUPS 962 bool "Control Group support" 963 select KERNFS 964 help 965 This option adds support for grouping sets of processes together, for 966 use with process control subsystems such as Cpusets, CFS, memory 967 controls or device isolation. 968 See 969 - Documentation/scheduler/sched-design-CFS.rst (CFS) 970 - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation 971 and resource control) 972 973 Say N if unsure. 974 975if CGROUPS 976 977config PAGE_COUNTER 978 bool 979 980config CGROUP_FAVOR_DYNMODS 981 bool "Favor dynamic modification latency reduction by default" 982 help 983 This option enables the "favordynmods" mount option by default 984 which reduces the latencies of dynamic cgroup modifications such 985 as task migrations and controller on/offs at the cost of making 986 hot path operations such as forks and exits more expensive. 987 988 Say N if unsure. 989 990config MEMCG 991 bool "Memory controller" 992 select PAGE_COUNTER 993 select EVENTFD 994 select SLAB_OBJ_EXT 995 help 996 Provides control over the memory footprint of tasks in a cgroup. 997 998config MEMCG_V1 999 bool "Legacy cgroup v1 memory controller" 1000 depends on MEMCG 1001 default n 1002 help 1003 Legacy cgroup v1 memory controller which has been deprecated by 1004 cgroup v2 implementation. The v1 is there for legacy applications 1005 which haven't migrated to the new cgroup v2 interface yet. If you 1006 do not have any such application then you are completely fine leaving 1007 this option disabled. 1008 1009 Please note that feature set of the legacy memory controller is likely 1010 going to shrink due to deprecation process. New deployments with v1 1011 controller are highly discouraged. 1012 1013 Say N if unsure. 1014 1015config BLK_CGROUP 1016 bool "IO controller" 1017 depends on BLOCK 1018 default n 1019 help 1020 Generic block IO controller cgroup interface. This is the common 1021 cgroup interface which should be used by various IO controlling 1022 policies. 1023 1024 Currently, CFQ IO scheduler uses it to recognize task groups and 1025 control disk bandwidth allocation (proportional time slice allocation) 1026 to such task groups. It is also used by bio throttling logic in 1027 block layer to implement upper limit in IO rates on a device. 1028 1029 This option only enables generic Block IO controller infrastructure. 1030 One needs to also enable actual IO controlling logic/policy. For 1031 enabling proportional weight division of disk bandwidth in CFQ, set 1032 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 1033 CONFIG_BLK_DEV_THROTTLING=y. 1034 1035 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information. 1036 1037config CGROUP_WRITEBACK 1038 bool 1039 depends on MEMCG && BLK_CGROUP 1040 default y 1041 1042menuconfig CGROUP_SCHED 1043 bool "CPU controller" 1044 default n 1045 help 1046 This feature lets CPU scheduler recognize task groups and control CPU 1047 bandwidth allocation to such task groups. It uses cgroups to group 1048 tasks. 1049 1050if CGROUP_SCHED 1051config GROUP_SCHED_WEIGHT 1052 def_bool n 1053 1054config FAIR_GROUP_SCHED 1055 bool "Group scheduling for SCHED_OTHER" 1056 depends on CGROUP_SCHED 1057 select GROUP_SCHED_WEIGHT 1058 default CGROUP_SCHED 1059 1060config CFS_BANDWIDTH 1061 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 1062 depends on FAIR_GROUP_SCHED 1063 default n 1064 help 1065 This option allows users to define CPU bandwidth rates (limits) for 1066 tasks running within the fair group scheduler. Groups with no limit 1067 set are considered to be unconstrained and will run with no 1068 restriction. 1069 See Documentation/scheduler/sched-bwc.rst for more information. 1070 1071config RT_GROUP_SCHED 1072 bool "Group scheduling for SCHED_RR/FIFO" 1073 depends on CGROUP_SCHED 1074 default n 1075 help 1076 This feature lets you explicitly allocate real CPU bandwidth 1077 to task groups. If enabled, it will also make it impossible to 1078 schedule realtime tasks for non-root users until you allocate 1079 realtime bandwidth for them. 1080 See Documentation/scheduler/sched-rt-group.rst for more information. 1081 1082config EXT_GROUP_SCHED 1083 bool 1084 depends on SCHED_CLASS_EXT && CGROUP_SCHED 1085 select GROUP_SCHED_WEIGHT 1086 default y 1087 1088endif #CGROUP_SCHED 1089 1090config SCHED_MM_CID 1091 def_bool y 1092 depends on SMP && RSEQ 1093 1094config UCLAMP_TASK_GROUP 1095 bool "Utilization clamping per group of tasks" 1096 depends on CGROUP_SCHED 1097 depends on UCLAMP_TASK 1098 default n 1099 help 1100 This feature enables the scheduler to track the clamped utilization 1101 of each CPU based on RUNNABLE tasks currently scheduled on that CPU. 1102 1103 When this option is enabled, the user can specify a min and max 1104 CPU bandwidth which is allowed for each single task in a group. 1105 The max bandwidth allows to clamp the maximum frequency a task 1106 can use, while the min bandwidth allows to define a minimum 1107 frequency a task will always use. 1108 1109 When task group based utilization clamping is enabled, an eventually 1110 specified task-specific clamp value is constrained by the cgroup 1111 specified clamp value. Both minimum and maximum task clamping cannot 1112 be bigger than the corresponding clamping defined at task group level. 1113 1114 If in doubt, say N. 1115 1116config CGROUP_PIDS 1117 bool "PIDs controller" 1118 help 1119 Provides enforcement of process number limits in the scope of a 1120 cgroup. Any attempt to fork more processes than is allowed in the 1121 cgroup will fail. PIDs are fundamentally a global resource because it 1122 is fairly trivial to reach PID exhaustion before you reach even a 1123 conservative kmemcg limit. As a result, it is possible to grind a 1124 system to halt without being limited by other cgroup policies. The 1125 PIDs controller is designed to stop this from happening. 1126 1127 It should be noted that organisational operations (such as attaching 1128 to a cgroup hierarchy) will *not* be blocked by the PIDs controller, 1129 since the PIDs limit only affects a process's ability to fork, not to 1130 attach to a cgroup. 1131 1132config CGROUP_RDMA 1133 bool "RDMA controller" 1134 select PAGE_COUNTER 1135 help 1136 Provides enforcement of RDMA resources defined by IB stack. 1137 It is fairly easy for consumers to exhaust RDMA resources, which 1138 can result into resource unavailability to other consumers. 1139 RDMA controller is designed to stop this from happening. 1140 Attaching processes with active RDMA resources to the cgroup 1141 hierarchy is allowed even if can cross the hierarchy's limit. 1142 1143config CGROUP_DMEM 1144 bool "Device memory controller (DMEM)" 1145 select PAGE_COUNTER 1146 help 1147 The DMEM controller allows compatible devices to restrict device 1148 memory usage based on the cgroup hierarchy. 1149 1150 As an example, it allows you to restrict VRAM usage for applications 1151 in the DRM subsystem. 1152 1153config CGROUP_FREEZER 1154 bool "Freezer controller" 1155 help 1156 Provides a way to freeze and unfreeze all tasks in a 1157 cgroup. 1158 1159 This option affects the ORIGINAL cgroup interface. The cgroup2 memory 1160 controller includes important in-kernel memory consumers per default. 1161 1162 If you're using cgroup2, say N. 1163 1164config CGROUP_HUGETLB 1165 bool "HugeTLB controller" 1166 depends on HUGETLB_PAGE 1167 select PAGE_COUNTER 1168 default n 1169 help 1170 Provides a cgroup controller for HugeTLB pages. 1171 When you enable this, you can put a per cgroup limit on HugeTLB usage. 1172 The limit is enforced during page fault. Since HugeTLB doesn't 1173 support page reclaim, enforcing the limit at page fault time implies 1174 that, the application will get SIGBUS signal if it tries to access 1175 HugeTLB pages beyond its limit. This requires the application to know 1176 beforehand how much HugeTLB pages it would require for its use. The 1177 control group is tracked in the third page lru pointer. This means 1178 that we cannot use the controller with huge page less than 3 pages. 1179 1180config CPUSETS 1181 bool "Cpuset controller" 1182 depends on SMP 1183 select UNION_FIND 1184 help 1185 This option will let you create and manage CPUSETs which 1186 allow dynamically partitioning a system into sets of CPUs and 1187 Memory Nodes and assigning tasks to run only within those sets. 1188 This is primarily useful on large SMP or NUMA systems. 1189 1190 Say N if unsure. 1191 1192config CPUSETS_V1 1193 bool "Legacy cgroup v1 cpusets controller" 1194 depends on CPUSETS 1195 default n 1196 help 1197 Legacy cgroup v1 cpusets controller which has been deprecated by 1198 cgroup v2 implementation. The v1 is there for legacy applications 1199 which haven't migrated to the new cgroup v2 interface yet. If you 1200 do not have any such application then you are completely fine leaving 1201 this option disabled. 1202 1203 Say N if unsure. 1204 1205config PROC_PID_CPUSET 1206 bool "Include legacy /proc/<pid>/cpuset file" 1207 depends on CPUSETS 1208 default y 1209 1210config CGROUP_DEVICE 1211 bool "Device controller" 1212 help 1213 Provides a cgroup controller implementing whitelists for 1214 devices which a process in the cgroup can mknod or open. 1215 1216config CGROUP_CPUACCT 1217 bool "Simple CPU accounting controller" 1218 help 1219 Provides a simple controller for monitoring the 1220 total CPU consumed by the tasks in a cgroup. 1221 1222config CGROUP_PERF 1223 bool "Perf controller" 1224 depends on PERF_EVENTS 1225 help 1226 This option extends the perf per-cpu mode to restrict monitoring 1227 to threads which belong to the cgroup specified and run on the 1228 designated cpu. Or this can be used to have cgroup ID in samples 1229 so that it can monitor performance events among cgroups. 1230 1231 Say N if unsure. 1232 1233config CGROUP_BPF 1234 bool "Support for eBPF programs attached to cgroups" 1235 depends on BPF_SYSCALL 1236 select SOCK_CGROUP_DATA 1237 help 1238 Allow attaching eBPF programs to a cgroup using the bpf(2) 1239 syscall command BPF_PROG_ATTACH. 1240 1241 In which context these programs are accessed depends on the type 1242 of attachment. For instance, programs that are attached using 1243 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of 1244 inet sockets. 1245 1246config CGROUP_MISC 1247 bool "Misc resource controller" 1248 default n 1249 help 1250 Provides a controller for miscellaneous resources on a host. 1251 1252 Miscellaneous scalar resources are the resources on the host system 1253 which cannot be abstracted like the other cgroups. This controller 1254 tracks and limits the miscellaneous resources used by a process 1255 attached to a cgroup hierarchy. 1256 1257 For more information, please check misc cgroup section in 1258 /Documentation/admin-guide/cgroup-v2.rst. 1259 1260config CGROUP_DEBUG 1261 bool "Debug controller" 1262 default n 1263 depends on DEBUG_KERNEL 1264 help 1265 This option enables a simple controller that exports 1266 debugging information about the cgroups framework. This 1267 controller is for control cgroup debugging only. Its 1268 interfaces are not stable. 1269 1270 Say N. 1271 1272config SOCK_CGROUP_DATA 1273 bool 1274 default n 1275 1276endif # CGROUPS 1277 1278menuconfig NAMESPACES 1279 bool "Namespaces support" if EXPERT 1280 depends on MULTIUSER 1281 default !EXPERT 1282 help 1283 Provides the way to make tasks work with different objects using 1284 the same id. For example same IPC id may refer to different objects 1285 or same user id or pid may refer to different tasks when used in 1286 different namespaces. 1287 1288if NAMESPACES 1289 1290config UTS_NS 1291 bool "UTS namespace" 1292 default y 1293 help 1294 In this namespace tasks see different info provided with the 1295 uname() system call 1296 1297config TIME_NS 1298 bool "TIME namespace" 1299 depends on GENERIC_VDSO_TIME_NS 1300 default y 1301 help 1302 In this namespace boottime and monotonic clocks can be set. 1303 The time will keep going with the same pace. 1304 1305config IPC_NS 1306 bool "IPC namespace" 1307 depends on (SYSVIPC || POSIX_MQUEUE) 1308 default y 1309 help 1310 In this namespace tasks work with IPC ids which correspond to 1311 different IPC objects in different namespaces. 1312 1313config USER_NS 1314 bool "User namespace" 1315 default n 1316 help 1317 This allows containers, i.e. vservers, to use user namespaces 1318 to provide different user info for different servers. 1319 1320 When user namespaces are enabled in the kernel it is 1321 recommended that the MEMCG option also be enabled and that 1322 user-space use the memory control groups to limit the amount 1323 of memory a memory unprivileged users can use. 1324 1325 If unsure, say N. 1326 1327config PID_NS 1328 bool "PID Namespaces" 1329 default y 1330 help 1331 Support process id namespaces. This allows having multiple 1332 processes with the same pid as long as they are in different 1333 pid namespaces. This is a building block of containers. 1334 1335config NET_NS 1336 bool "Network namespace" 1337 depends on NET 1338 default y 1339 help 1340 Allow user space to create what appear to be multiple instances 1341 of the network stack. 1342 1343endif # NAMESPACES 1344 1345config CHECKPOINT_RESTORE 1346 bool "Checkpoint/restore support" 1347 depends on PROC_FS 1348 select PROC_CHILDREN 1349 select KCMP 1350 default n 1351 help 1352 Enables additional kernel features in a sake of checkpoint/restore. 1353 In particular it adds auxiliary prctl codes to setup process text, 1354 data and heap segment sizes, and a few additional /proc filesystem 1355 entries. 1356 1357 If unsure, say N here. 1358 1359config SCHED_AUTOGROUP 1360 bool "Automatic process group scheduling" 1361 select CGROUPS 1362 select CGROUP_SCHED 1363 select FAIR_GROUP_SCHED 1364 help 1365 This option optimizes the scheduler for common desktop workloads by 1366 automatically creating and populating task groups. This separation 1367 of workloads isolates aggressive CPU burners (like build jobs) from 1368 desktop applications. Task group autogeneration is currently based 1369 upon task session. 1370 1371config RELAY 1372 bool "Kernel->user space relay support (formerly relayfs)" 1373 select IRQ_WORK 1374 help 1375 This option enables support for relay interface support in 1376 certain file systems (such as debugfs). 1377 It is designed to provide an efficient mechanism for tools and 1378 facilities to relay large amounts of data from kernel space to 1379 user space. 1380 1381 If unsure, say N. 1382 1383config BLK_DEV_INITRD 1384 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1385 help 1386 The initial RAM filesystem is a ramfs which is loaded by the 1387 boot loader (loadlin or lilo) and that is mounted as root 1388 before the normal boot procedure. It is typically used to 1389 load modules needed to mount the "real" root file system, 1390 etc. See <file:Documentation/admin-guide/initrd.rst> for details. 1391 1392 If RAM disk support (BLK_DEV_RAM) is also included, this 1393 also enables initial RAM disk (initrd) support and adds 1394 15 Kbytes (more on some other architectures) to the kernel size. 1395 1396 If unsure say Y. 1397 1398if BLK_DEV_INITRD 1399 1400source "usr/Kconfig" 1401 1402endif 1403 1404config BOOT_CONFIG 1405 bool "Boot config support" 1406 select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED 1407 help 1408 Extra boot config allows system admin to pass a config file as 1409 complemental extension of kernel cmdline when booting. 1410 The boot config file must be attached at the end of initramfs 1411 with checksum, size and magic word. 1412 See <file:Documentation/admin-guide/bootconfig.rst> for details. 1413 1414 If unsure, say Y. 1415 1416config BOOT_CONFIG_FORCE 1417 bool "Force unconditional bootconfig processing" 1418 depends on BOOT_CONFIG 1419 default y if BOOT_CONFIG_EMBED 1420 help 1421 With this Kconfig option set, BOOT_CONFIG processing is carried 1422 out even when the "bootconfig" kernel-boot parameter is omitted. 1423 In fact, with this Kconfig option set, there is no way to 1424 make the kernel ignore the BOOT_CONFIG-supplied kernel-boot 1425 parameters. 1426 1427 If unsure, say N. 1428 1429config BOOT_CONFIG_EMBED 1430 bool "Embed bootconfig file in the kernel" 1431 depends on BOOT_CONFIG 1432 help 1433 Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the 1434 kernel. Usually, the bootconfig file is loaded with the initrd 1435 image. But if the system doesn't support initrd, this option will 1436 help you by embedding a bootconfig file while building the kernel. 1437 1438 If unsure, say N. 1439 1440config BOOT_CONFIG_EMBED_FILE 1441 string "Embedded bootconfig file path" 1442 depends on BOOT_CONFIG_EMBED 1443 help 1444 Specify a bootconfig file which will be embedded to the kernel. 1445 This bootconfig will be used if there is no initrd or no other 1446 bootconfig in the initrd. 1447 1448config INITRAMFS_PRESERVE_MTIME 1449 bool "Preserve cpio archive mtimes in initramfs" 1450 default y 1451 help 1452 Each entry in an initramfs cpio archive carries an mtime value. When 1453 enabled, extracted cpio items take this mtime, with directory mtime 1454 setting deferred until after creation of any child entries. 1455 1456 If unsure, say Y. 1457 1458choice 1459 prompt "Compiler optimization level" 1460 default CC_OPTIMIZE_FOR_PERFORMANCE 1461 1462config CC_OPTIMIZE_FOR_PERFORMANCE 1463 bool "Optimize for performance (-O2)" 1464 help 1465 This is the default optimization level for the kernel, building 1466 with the "-O2" compiler flag for best performance and most 1467 helpful compile-time warnings. 1468 1469config CC_OPTIMIZE_FOR_SIZE 1470 bool "Optimize for size (-Os)" 1471 help 1472 Choosing this option will pass "-Os" to your compiler resulting 1473 in a smaller kernel. 1474 1475endchoice 1476 1477config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1478 bool 1479 help 1480 This requires that the arch annotates or otherwise protects 1481 its external entry points from being discarded. Linker scripts 1482 must also merge .text.*, .data.*, and .bss.* correctly into 1483 output sections. Care must be taken not to pull in unrelated 1484 sections (e.g., '.text.init'). Typically '.' in section names 1485 is used to distinguish them from label names / C identifiers. 1486 1487config LD_DEAD_CODE_DATA_ELIMINATION 1488 bool "Dead code and data elimination (EXPERIMENTAL)" 1489 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1490 depends on EXPERT 1491 depends on $(cc-option,-ffunction-sections -fdata-sections) 1492 depends on $(ld-option,--gc-sections) 1493 help 1494 Enable this if you want to do dead code and data elimination with 1495 the linker by compiling with -ffunction-sections -fdata-sections, 1496 and linking with --gc-sections. 1497 1498 This can reduce on disk and in-memory size of the kernel 1499 code and static data, particularly for small configs and 1500 on small systems. This has the possibility of introducing 1501 silently broken kernel if the required annotations are not 1502 present. This option is not well tested yet, so use at your 1503 own risk. 1504 1505config LD_ORPHAN_WARN 1506 def_bool y 1507 depends on ARCH_WANT_LD_ORPHAN_WARN 1508 depends on $(ld-option,--orphan-handling=warn) 1509 depends on $(ld-option,--orphan-handling=error) 1510 1511config LD_ORPHAN_WARN_LEVEL 1512 string 1513 depends on LD_ORPHAN_WARN 1514 default "error" if WERROR 1515 default "warn" 1516 1517config SYSCTL 1518 bool 1519 1520config HAVE_UID16 1521 bool 1522 1523config SYSCTL_EXCEPTION_TRACE 1524 bool 1525 help 1526 Enable support for /proc/sys/debug/exception-trace. 1527 1528config SYSCTL_ARCH_UNALIGN_NO_WARN 1529 bool 1530 help 1531 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1532 Allows arch to define/use @no_unaligned_warning to possibly warn 1533 about unaligned access emulation going on under the hood. 1534 1535config SYSCTL_ARCH_UNALIGN_ALLOW 1536 bool 1537 help 1538 Enable support for /proc/sys/kernel/unaligned-trap 1539 Allows arches to define/use @unaligned_enabled to runtime toggle 1540 the unaligned access emulation. 1541 see arch/parisc/kernel/unaligned.c for reference 1542 1543config HAVE_PCSPKR_PLATFORM 1544 bool 1545 1546menuconfig EXPERT 1547 bool "Configure standard kernel features (expert users)" 1548 # Unhide debug options, to make the on-by-default options visible 1549 select DEBUG_KERNEL 1550 help 1551 This option allows certain base kernel options and settings 1552 to be disabled or tweaked. This is for specialized 1553 environments which can tolerate a "non-standard" kernel. 1554 Only use this if you really know what you are doing. 1555 1556config UID16 1557 bool "Enable 16-bit UID system calls" if EXPERT 1558 depends on HAVE_UID16 && MULTIUSER 1559 default y 1560 help 1561 This enables the legacy 16-bit UID syscall wrappers. 1562 1563config MULTIUSER 1564 bool "Multiple users, groups and capabilities support" if EXPERT 1565 default y 1566 help 1567 This option enables support for non-root users, groups and 1568 capabilities. 1569 1570 If you say N here, all processes will run with UID 0, GID 0, and all 1571 possible capabilities. Saying N here also compiles out support for 1572 system calls related to UIDs, GIDs, and capabilities, such as setuid, 1573 setgid, and capset. 1574 1575 If unsure, say Y here. 1576 1577config SGETMASK_SYSCALL 1578 bool "sgetmask/ssetmask syscalls support" if EXPERT 1579 default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH 1580 help 1581 sys_sgetmask and sys_ssetmask are obsolete system calls 1582 no longer supported in libc but still enabled by default in some 1583 architectures. 1584 1585 If unsure, leave the default option here. 1586 1587config SYSFS_SYSCALL 1588 bool "Sysfs syscall support" if EXPERT 1589 default y 1590 help 1591 sys_sysfs is an obsolete system call no longer supported in libc. 1592 Note that disabling this option is more secure but might break 1593 compatibility with some systems. 1594 1595 If unsure say Y here. 1596 1597config FHANDLE 1598 bool "open by fhandle syscalls" if EXPERT 1599 select EXPORTFS 1600 default y 1601 help 1602 If you say Y here, a user level program will be able to map 1603 file names to handle and then later use the handle for 1604 different file system operations. This is useful in implementing 1605 userspace file servers, which now track files using handles instead 1606 of names. The handle would remain the same even if file names 1607 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 1608 syscalls. 1609 1610config POSIX_TIMERS 1611 bool "Posix Clocks & timers" if EXPERT 1612 default y 1613 help 1614 This includes native support for POSIX timers to the kernel. 1615 Some embedded systems have no use for them and therefore they 1616 can be configured out to reduce the size of the kernel image. 1617 1618 When this option is disabled, the following syscalls won't be 1619 available: timer_create, timer_gettime: timer_getoverrun, 1620 timer_settime, timer_delete, clock_adjtime, getitimer, 1621 setitimer, alarm. Furthermore, the clock_settime, clock_gettime, 1622 clock_getres and clock_nanosleep syscalls will be limited to 1623 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. 1624 1625 If unsure say y. 1626 1627config PRINTK 1628 default y 1629 bool "Enable support for printk" if EXPERT 1630 select IRQ_WORK 1631 help 1632 This option enables normal printk support. Removing it 1633 eliminates most of the message strings from the kernel image 1634 and makes the kernel more or less silent. As this makes it 1635 very difficult to diagnose system problems, saying N here is 1636 strongly discouraged. 1637 1638config BUG 1639 bool "BUG() support" if EXPERT 1640 default y 1641 help 1642 Disabling this option eliminates support for BUG and WARN, reducing 1643 the size of your kernel image and potentially quietly ignoring 1644 numerous fatal conditions. You should only consider disabling this 1645 option for embedded systems with no facilities for reporting errors. 1646 Just say Y. 1647 1648config ELF_CORE 1649 depends on COREDUMP 1650 default y 1651 bool "Enable ELF core dumps" if EXPERT 1652 help 1653 Enable support for generating core dumps. Disabling saves about 4k. 1654 1655 1656config PCSPKR_PLATFORM 1657 bool "Enable PC-Speaker support" if EXPERT 1658 depends on HAVE_PCSPKR_PLATFORM 1659 select I8253_LOCK 1660 default y 1661 help 1662 This option allows to disable the internal PC-Speaker 1663 support, saving some memory. 1664 1665config BASE_SMALL 1666 bool "Enable smaller-sized data structures for core" if EXPERT 1667 help 1668 Enabling this option reduces the size of miscellaneous core 1669 kernel data structures. This saves memory on small machines, 1670 but may reduce performance. 1671 1672config FUTEX 1673 bool "Enable futex support" if EXPERT 1674 depends on !(SPARC32 && SMP) 1675 default y 1676 imply RT_MUTEXES 1677 help 1678 Disabling this option will cause the kernel to be built without 1679 support for "fast userspace mutexes". The resulting kernel may not 1680 run glibc-based applications correctly. 1681 1682config FUTEX_PI 1683 bool 1684 depends on FUTEX && RT_MUTEXES 1685 default y 1686 1687config EPOLL 1688 bool "Enable eventpoll support" if EXPERT 1689 default y 1690 help 1691 Disabling this option will cause the kernel to be built without 1692 support for epoll family of system calls. 1693 1694config SIGNALFD 1695 bool "Enable signalfd() system call" if EXPERT 1696 default y 1697 help 1698 Enable the signalfd() system call that allows to receive signals 1699 on a file descriptor. 1700 1701 If unsure, say Y. 1702 1703config TIMERFD 1704 bool "Enable timerfd() system call" if EXPERT 1705 default y 1706 help 1707 Enable the timerfd() system call that allows to receive timer 1708 events on a file descriptor. 1709 1710 If unsure, say Y. 1711 1712config EVENTFD 1713 bool "Enable eventfd() system call" if EXPERT 1714 default y 1715 help 1716 Enable the eventfd() system call that allows to receive both 1717 kernel notification (ie. KAIO) or userspace notifications. 1718 1719 If unsure, say Y. 1720 1721config SHMEM 1722 bool "Use full shmem filesystem" if EXPERT 1723 default y 1724 depends on MMU 1725 help 1726 The shmem is an internal filesystem used to manage shared memory. 1727 It is backed by swap and manages resource limits. It is also exported 1728 to userspace as tmpfs if TMPFS is enabled. Disabling this 1729 option replaces shmem and tmpfs with the much simpler ramfs code, 1730 which may be appropriate on small systems without swap. 1731 1732config AIO 1733 bool "Enable AIO support" if EXPERT 1734 default y 1735 help 1736 This option enables POSIX asynchronous I/O which may by used 1737 by some high performance threaded applications. Disabling 1738 this option saves about 7k. 1739 1740config IO_URING 1741 bool "Enable IO uring support" if EXPERT 1742 select IO_WQ 1743 default y 1744 help 1745 This option enables support for the io_uring interface, enabling 1746 applications to submit and complete IO through submission and 1747 completion rings that are shared between the kernel and application. 1748 1749config GCOV_PROFILE_URING 1750 bool "Enable GCOV profiling on the io_uring subsystem" 1751 depends on GCOV_KERNEL 1752 help 1753 Enable GCOV profiling on the io_uring subsystem, to facilitate 1754 code coverage testing. 1755 1756 If unsure, say N. 1757 1758 Note that this will have a negative impact on the performance of 1759 the io_uring subsystem, hence this should only be enabled for 1760 specific test purposes. 1761 1762config ADVISE_SYSCALLS 1763 bool "Enable madvise/fadvise syscalls" if EXPERT 1764 default y 1765 help 1766 This option enables the madvise and fadvise syscalls, used by 1767 applications to advise the kernel about their future memory or file 1768 usage, improving performance. If building an embedded system where no 1769 applications use these syscalls, you can disable this option to save 1770 space. 1771 1772config MEMBARRIER 1773 bool "Enable membarrier() system call" if EXPERT 1774 default y 1775 help 1776 Enable the membarrier() system call that allows issuing memory 1777 barriers across all running threads, which can be used to distribute 1778 the cost of user-space memory barriers asymmetrically by transforming 1779 pairs of memory barriers into pairs consisting of membarrier() and a 1780 compiler barrier. 1781 1782 If unsure, say Y. 1783 1784config KCMP 1785 bool "Enable kcmp() system call" if EXPERT 1786 help 1787 Enable the kernel resource comparison system call. It provides 1788 user-space with the ability to compare two processes to see if they 1789 share a common resource, such as a file descriptor or even virtual 1790 memory space. 1791 1792 If unsure, say N. 1793 1794config RSEQ 1795 bool "Enable rseq() system call" if EXPERT 1796 default y 1797 depends on HAVE_RSEQ 1798 select MEMBARRIER 1799 help 1800 Enable the restartable sequences system call. It provides a 1801 user-space cache for the current CPU number value, which 1802 speeds up getting the current CPU number from user-space, 1803 as well as an ABI to speed up user-space operations on 1804 per-CPU data. 1805 1806 If unsure, say Y. 1807 1808config DEBUG_RSEQ 1809 default n 1810 bool "Enable debugging of rseq() system call" if EXPERT 1811 depends on RSEQ && DEBUG_KERNEL 1812 help 1813 Enable extra debugging checks for the rseq system call. 1814 1815 If unsure, say N. 1816 1817config CACHESTAT_SYSCALL 1818 bool "Enable cachestat() system call" if EXPERT 1819 default y 1820 help 1821 Enable the cachestat system call, which queries the page cache 1822 statistics of a file (number of cached pages, dirty pages, 1823 pages marked for writeback, (recently) evicted pages). 1824 1825 If unsure say Y here. 1826 1827config PC104 1828 bool "PC/104 support" if EXPERT 1829 help 1830 Expose PC/104 form factor device drivers and options available for 1831 selection and configuration. Enable this option if your target 1832 machine has a PC/104 bus. 1833 1834config KALLSYMS 1835 bool "Load all symbols for debugging/ksymoops" if EXPERT 1836 default y 1837 help 1838 Say Y here to let the kernel print out symbolic crash information and 1839 symbolic stack backtraces. This increases the size of the kernel 1840 somewhat, as all symbols have to be loaded into the kernel image. 1841 1842config KALLSYMS_SELFTEST 1843 bool "Test the basic functions and performance of kallsyms" 1844 depends on KALLSYMS 1845 default n 1846 help 1847 Test the basic functions and performance of some interfaces, such as 1848 kallsyms_lookup_name. It also calculates the compression rate of the 1849 kallsyms compression algorithm for the current symbol set. 1850 1851 Start self-test automatically after system startup. Suggest executing 1852 "dmesg | grep kallsyms_selftest" to collect test results. "finish" is 1853 displayed in the last line, indicating that the test is complete. 1854 1855config KALLSYMS_ALL 1856 bool "Include all symbols in kallsyms" 1857 depends on DEBUG_KERNEL && KALLSYMS 1858 help 1859 Normally kallsyms only contains the symbols of functions for nicer 1860 OOPS messages and backtraces (i.e., symbols from the text and inittext 1861 sections). This is sufficient for most cases. And only if you want to 1862 enable kernel live patching, or other less common use cases (e.g., 1863 when a debugger is used) all symbols are required (i.e., names of 1864 variables from the data sections, etc). 1865 1866 This option makes sure that all symbols are loaded into the kernel 1867 image (i.e., symbols from all sections) in cost of increased kernel 1868 size (depending on the kernel configuration, it may be 300KiB or 1869 something like this). 1870 1871 Say N unless you really need all symbols, or kernel live patching. 1872 1873config KALLSYMS_ABSOLUTE_PERCPU 1874 bool 1875 depends on KALLSYMS 1876 default X86_64 && SMP 1877 1878# end of the "standard kernel features (expert users)" menu 1879 1880config ARCH_HAS_MEMBARRIER_CALLBACKS 1881 bool 1882 1883config ARCH_HAS_MEMBARRIER_SYNC_CORE 1884 bool 1885 1886config HAVE_PERF_EVENTS 1887 bool 1888 help 1889 See tools/perf/design.txt for details. 1890 1891config GUEST_PERF_EVENTS 1892 bool 1893 depends on HAVE_PERF_EVENTS 1894 1895config PERF_USE_VMALLOC 1896 bool 1897 help 1898 See tools/perf/design.txt for details 1899 1900menu "Kernel Performance Events And Counters" 1901 1902config PERF_EVENTS 1903 bool "Kernel performance events and counters" 1904 default y if PROFILING 1905 depends on HAVE_PERF_EVENTS 1906 select IRQ_WORK 1907 help 1908 Enable kernel support for various performance events provided 1909 by software and hardware. 1910 1911 Software events are supported either built-in or via the 1912 use of generic tracepoints. 1913 1914 Most modern CPUs support performance events via performance 1915 counter registers. These registers count the number of certain 1916 types of hw events: such as instructions executed, cachemisses 1917 suffered, or branches mis-predicted - without slowing down the 1918 kernel or applications. These registers can also trigger interrupts 1919 when a threshold number of events have passed - and can thus be 1920 used to profile the code that runs on that CPU. 1921 1922 The Linux Performance Event subsystem provides an abstraction of 1923 these software and hardware event capabilities, available via a 1924 system call and used by the "perf" utility in tools/perf/. It 1925 provides per task and per CPU counters, and it provides event 1926 capabilities on top of those. 1927 1928 Say Y if unsure. 1929 1930config DEBUG_PERF_USE_VMALLOC 1931 default n 1932 bool "Debug: use vmalloc to back perf mmap() buffers" 1933 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC 1934 select PERF_USE_VMALLOC 1935 help 1936 Use vmalloc memory to back perf mmap() buffers. 1937 1938 Mostly useful for debugging the vmalloc code on platforms 1939 that don't require it. 1940 1941 Say N if unsure. 1942 1943endmenu 1944 1945config SYSTEM_DATA_VERIFICATION 1946 def_bool n 1947 select SYSTEM_TRUSTED_KEYRING 1948 select KEYS 1949 select CRYPTO 1950 select CRYPTO_RSA 1951 select ASYMMETRIC_KEY_TYPE 1952 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 1953 select ASN1 1954 select OID_REGISTRY 1955 select X509_CERTIFICATE_PARSER 1956 select PKCS7_MESSAGE_PARSER 1957 help 1958 Provide PKCS#7 message verification using the contents of the system 1959 trusted keyring to provide public keys. This then can be used for 1960 module verification, kexec image verification and firmware blob 1961 verification. 1962 1963config PROFILING 1964 bool "Profiling support" 1965 help 1966 Say Y here to enable the extended profiling support mechanisms used 1967 by profilers. 1968 1969config RUST 1970 bool "Rust support" 1971 depends on HAVE_RUST 1972 depends on RUST_IS_AVAILABLE 1973 depends on !MODVERSIONS 1974 depends on !GCC_PLUGIN_RANDSTRUCT 1975 depends on !RANDSTRUCT 1976 depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE 1977 depends on !CFI_CLANG || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC 1978 select CFI_ICALL_NORMALIZE_INTEGERS if CFI_CLANG 1979 depends on !CALL_PADDING || RUSTC_VERSION >= 108100 1980 depends on !KASAN_SW_TAGS 1981 depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300 1982 help 1983 Enables Rust support in the kernel. 1984 1985 This allows other Rust-related options, like drivers written in Rust, 1986 to be selected. 1987 1988 It is also required to be able to load external kernel modules 1989 written in Rust. 1990 1991 See Documentation/rust/ for more information. 1992 1993 If unsure, say N. 1994 1995config RUSTC_VERSION_TEXT 1996 string 1997 depends on RUST 1998 default "$(RUSTC_VERSION_TEXT)" 1999 help 2000 See `CC_VERSION_TEXT`. 2001 2002config BINDGEN_VERSION_TEXT 2003 string 2004 depends on RUST 2005 # The dummy parameter `workaround-for-0.69.0` is required to support 0.69.0 2006 # (https://github.com/rust-lang/rust-bindgen/pull/2678) and 0.71.0 2007 # (https://github.com/rust-lang/rust-bindgen/pull/3040). It can be removed 2008 # when the minimum version is upgraded past the latter (0.69.1 and 0.71.1 2009 # both fixed the issue). 2010 default "$(shell,$(BINDGEN) --version workaround-for-0.69.0 2>/dev/null)" 2011 2012# 2013# Place an empty function call at each tracepoint site. Can be 2014# dynamically changed for a probe function. 2015# 2016config TRACEPOINTS 2017 bool 2018 select TASKS_TRACE_RCU 2019 2020source "kernel/Kconfig.kexec" 2021 2022endmenu # General setup 2023 2024source "arch/Kconfig" 2025 2026config RT_MUTEXES 2027 bool 2028 default y if PREEMPT_RT 2029 2030config MODULE_SIG_FORMAT 2031 def_bool n 2032 select SYSTEM_DATA_VERIFICATION 2033 2034source "kernel/module/Kconfig" 2035 2036config INIT_ALL_POSSIBLE 2037 bool 2038 help 2039 Back when each arch used to define their own cpu_online_mask and 2040 cpu_possible_mask, some of them chose to initialize cpu_possible_mask 2041 with all 1s, and others with all 0s. When they were centralised, 2042 it was better to provide this option than to break all the archs 2043 and have several arch maintainers pursuing me down dark alleys. 2044 2045source "block/Kconfig" 2046 2047config PREEMPT_NOTIFIERS 2048 bool 2049 2050config PADATA 2051 depends on SMP 2052 bool 2053 2054config ASN1 2055 tristate 2056 help 2057 Build a simple ASN.1 grammar compiler that produces a bytecode output 2058 that can be interpreted by the ASN.1 stream decoder and used to 2059 inform it as to what tags are to be expected in a stream and what 2060 functions to call on what tags. 2061 2062source "kernel/Kconfig.locks" 2063 2064config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 2065 bool 2066 2067config ARCH_HAS_PREPARE_SYNC_CORE_CMD 2068 bool 2069 2070config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2071 bool 2072 2073# It may be useful for an architecture to override the definitions of the 2074# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> 2075# and the COMPAT_ variants in <linux/compat.h>, in particular to use a 2076# different calling convention for syscalls. They can also override the 2077# macros for not-implemented syscalls in kernel/sys_ni.c and 2078# kernel/time/posix-stubs.c. All these overrides need to be available in 2079# <asm/syscall_wrapper.h>. 2080config ARCH_HAS_SYSCALL_WRAPPER 2081 def_bool n 2082