1# SPDX-License-Identifier: GPL-2.0-only 2 3source "scripts/Kconfig.toolchain" 4 5config CONSTRUCTORS 6 bool 7 8config IRQ_WORK 9 def_bool y if SMP 10 11config BUILDTIME_TABLE_SORT 12 bool 13 14config THREAD_INFO_IN_TASK 15 bool 16 help 17 Select this to move thread_info off the stack into task_struct. To 18 make this work, an arch will need to remove all thread_info fields 19 except flags and fix any runtime bugs. 20 21 One subtle change that will be needed is to use try_get_task_stack() 22 and put_task_stack() in save_thread_stack_tsk() and get_wchan(). 23 24menu "General setup" 25 26config BROKEN 27 bool 28 help 29 This option allows you to choose whether you want to try to 30 compile (and fix) old drivers that haven't been updated to 31 new infrastructure. 32 33config BROKEN_ON_SMP 34 bool 35 depends on BROKEN || !SMP 36 default y 37 38config INIT_ENV_ARG_LIMIT 39 int 40 default 32 if !UML 41 default 128 if UML 42 help 43 Maximum of each of the number of arguments and environment 44 variables passed to init from the kernel command line. 45 46config COMPILE_TEST 47 bool "Compile also drivers which will not load" 48 depends on HAS_IOMEM 49 help 50 Some drivers can be compiled on a different platform than they are 51 intended to be run on. Despite they cannot be loaded there (or even 52 when they load they cannot be used due to missing HW support), 53 developers still, opposing to distributors, might want to build such 54 drivers to compile-test them. 55 56 If you are a developer and want to build everything available, say Y 57 here. If you are a user/distributor, say N here to exclude useless 58 drivers to be distributed. 59 60config WERROR 61 bool "Compile the kernel with warnings as errors" 62 default COMPILE_TEST 63 help 64 A kernel build should not cause any compiler warnings, and this 65 enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags 66 to enforce that rule by default. Certain warnings from other tools 67 such as the linker may be upgraded to errors with this option as 68 well. 69 70 However, if you have a new (or very old) compiler or linker with odd 71 and unusual warnings, or you have some architecture with problems, 72 you may need to disable this config option in order to 73 successfully build the kernel. 74 75 If in doubt, say Y. 76 77config UAPI_HEADER_TEST 78 bool "Compile test UAPI headers" 79 depends on HEADERS_INSTALL 80 help 81 Compile test headers exported to user-space to ensure they are 82 self-contained, i.e. compilable as standalone units. 83 84 If you are a developer or tester and want to ensure the exported 85 headers are self-contained, say Y here. Otherwise, choose N. 86 87config LOCALVERSION 88 string "Local version - append to kernel release" 89 help 90 Append an extra string to the end of your kernel version. 91 This will show up when you type uname, for example. 92 The string you set here will be appended after the contents of 93 any files with a filename matching localversion* in your 94 object and source tree, in that order. Your total string can 95 be a maximum of 64 characters. 96 97config LOCALVERSION_AUTO 98 bool "Automatically append version information to the version string" 99 default y 100 depends on !COMPILE_TEST 101 help 102 This will try to automatically determine if the current tree is a 103 release tree by looking for git tags that belong to the current 104 top of tree revision. 105 106 A string of the format -gxxxxxxxx will be added to the localversion 107 if a git-based tree is found. The string generated by this will be 108 appended after any matching localversion* files, and after the value 109 set in CONFIG_LOCALVERSION. 110 111 (The actual string used here is the first 12 characters produced 112 by running the command: 113 114 $ git rev-parse --verify HEAD 115 116 which is done within the script "scripts/setlocalversion".) 117 118config BUILD_SALT 119 string "Build ID Salt" 120 default "" 121 help 122 The build ID is used to link binaries and their debug info. Setting 123 this option will use the value in the calculation of the build id. 124 This is mostly useful for distributions which want to ensure the 125 build is unique between builds. It's safe to leave the default. 126 127config HAVE_KERNEL_GZIP 128 bool 129 130config HAVE_KERNEL_BZIP2 131 bool 132 133config HAVE_KERNEL_LZMA 134 bool 135 136config HAVE_KERNEL_XZ 137 bool 138 139config HAVE_KERNEL_LZO 140 bool 141 142config HAVE_KERNEL_LZ4 143 bool 144 145config HAVE_KERNEL_ZSTD 146 bool 147 148config HAVE_KERNEL_UNCOMPRESSED 149 bool 150 151choice 152 prompt "Kernel compression mode" 153 default KERNEL_GZIP 154 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 155 help 156 The linux kernel is a kind of self-extracting executable. 157 Several compression algorithms are available, which differ 158 in efficiency, compression and decompression speed. 159 Compression speed is only relevant when building a kernel. 160 Decompression speed is relevant at each boot. 161 162 If you have any problems with bzip2 or lzma compressed 163 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older 164 version of this functionality (bzip2 only), for 2.4, was 165 supplied by Christian Ludwig) 166 167 High compression options are mostly useful for users, who 168 are low on disk space (embedded systems), but for whom ram 169 size matters less. 170 171 If in doubt, select 'gzip' 172 173config KERNEL_GZIP 174 bool "Gzip" 175 depends on HAVE_KERNEL_GZIP 176 help 177 The old and tried gzip compression. It provides a good balance 178 between compression ratio and decompression speed. 179 180config KERNEL_BZIP2 181 bool "Bzip2" 182 depends on HAVE_KERNEL_BZIP2 183 help 184 Its compression ratio and speed is intermediate. 185 Decompression speed is slowest among the choices. The kernel 186 size is about 10% smaller with bzip2, in comparison to gzip. 187 Bzip2 uses a large amount of memory. For modern kernels you 188 will need at least 8MB RAM or more for booting. 189 190config KERNEL_LZMA 191 bool "LZMA" 192 depends on HAVE_KERNEL_LZMA 193 help 194 This compression algorithm's ratio is best. Decompression speed 195 is between gzip and bzip2. Compression is slowest. 196 The kernel size is about 33% smaller with LZMA in comparison to gzip. 197 198config KERNEL_XZ 199 bool "XZ" 200 depends on HAVE_KERNEL_XZ 201 help 202 XZ uses the LZMA2 algorithm and instruction set specific 203 BCJ filters which can improve compression ratio of executable 204 code. The size of the kernel is about 30% smaller with XZ in 205 comparison to gzip. On architectures for which there is a BCJ 206 filter (i386, x86_64, ARM, ARM64, RISC-V, big endian PowerPC, 207 and SPARC), XZ will create a few percent smaller kernel than 208 plain LZMA. 209 210 The speed is about the same as with LZMA: The decompression 211 speed of XZ is better than that of bzip2 but worse than gzip 212 and LZO. Compression is slow. 213 214config KERNEL_LZO 215 bool "LZO" 216 depends on HAVE_KERNEL_LZO 217 help 218 Its compression ratio is the poorest among the choices. The kernel 219 size is about 10% bigger than gzip; however its speed 220 (both compression and decompression) is the fastest. 221 222config KERNEL_LZ4 223 bool "LZ4" 224 depends on HAVE_KERNEL_LZ4 225 help 226 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. 227 A preliminary version of LZ4 de/compression tool is available at 228 <https://code.google.com/p/lz4/>. 229 230 Its compression ratio is worse than LZO. The size of the kernel 231 is about 8% bigger than LZO. But the decompression speed is 232 faster than LZO. 233 234config KERNEL_ZSTD 235 bool "ZSTD" 236 depends on HAVE_KERNEL_ZSTD 237 help 238 ZSTD is a compression algorithm targeting intermediate compression 239 with fast decompression speed. It will compress better than GZIP and 240 decompress around the same speed as LZO, but slower than LZ4. You 241 will need at least 192 KB RAM or more for booting. The zstd command 242 line tool is required for compression. 243 244config KERNEL_UNCOMPRESSED 245 bool "None" 246 depends on HAVE_KERNEL_UNCOMPRESSED 247 help 248 Produce uncompressed kernel image. This option is usually not what 249 you want. It is useful for debugging the kernel in slow simulation 250 environments, where decompressing and moving the kernel is awfully 251 slow. This option allows early boot code to skip the decompressor 252 and jump right at uncompressed kernel image. 253 254endchoice 255 256config DEFAULT_INIT 257 string "Default init path" 258 default "" 259 help 260 This option determines the default init for the system if no init= 261 option is passed on the kernel command line. If the requested path is 262 not present, we will still then move on to attempting further 263 locations (e.g. /sbin/init, etc). If this is empty, we will just use 264 the fallback list when init= is not passed. 265 266config DEFAULT_HOSTNAME 267 string "Default hostname" 268 default "(none)" 269 help 270 This option determines the default system hostname before userspace 271 calls sethostname(2). The kernel traditionally uses "(none)" here, 272 but you may wish to use a different default here to make a minimal 273 system more usable with less configuration. 274 275config SYSVIPC 276 bool "System V IPC" 277 help 278 Inter Process Communication is a suite of library functions and 279 system calls which let processes (running programs) synchronize and 280 exchange information. It is generally considered to be a good thing, 281 and some programs won't run unless you say Y here. In particular, if 282 you want to run the DOS emulator dosemu under Linux (read the 283 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 284 you'll need to say Y here. 285 286 You can find documentation about IPC with "info ipc" and also in 287 section 6.4 of the Linux Programmer's Guide, available from 288 <http://www.tldp.org/guides.html>. 289 290config SYSVIPC_SYSCTL 291 bool 292 depends on SYSVIPC 293 depends on SYSCTL 294 default y 295 296config SYSVIPC_COMPAT 297 def_bool y 298 depends on COMPAT && SYSVIPC 299 300config POSIX_MQUEUE 301 bool "POSIX Message Queues" 302 depends on NET 303 help 304 POSIX variant of message queues is a part of IPC. In POSIX message 305 queues every message has a priority which decides about succession 306 of receiving it by a process. If you want to compile and run 307 programs written e.g. for Solaris with use of its POSIX message 308 queues (functions mq_*) say Y here. 309 310 POSIX message queues are visible as a filesystem called 'mqueue' 311 and can be mounted somewhere if you want to do filesystem 312 operations on message queues. 313 314 If unsure, say Y. 315 316config POSIX_MQUEUE_SYSCTL 317 bool 318 depends on POSIX_MQUEUE 319 depends on SYSCTL 320 default y 321 322config WATCH_QUEUE 323 bool "General notification queue" 324 default n 325 help 326 327 This is a general notification queue for the kernel to pass events to 328 userspace by splicing them into pipes. It can be used in conjunction 329 with watches for key/keyring change notifications and device 330 notifications. 331 332 See Documentation/core-api/watch_queue.rst 333 334config CROSS_MEMORY_ATTACH 335 bool "Enable process_vm_readv/writev syscalls" 336 depends on MMU 337 default y 338 help 339 Enabling this option adds the system calls process_vm_readv and 340 process_vm_writev which allow a process with the correct privileges 341 to directly read from or write to another process' address space. 342 See the man page for more details. 343 344config AUDIT 345 bool "Auditing support" 346 depends on NET 347 help 348 Enable auditing infrastructure that can be used with another 349 kernel subsystem, such as SELinux (which requires this for 350 logging of avc messages output). System call auditing is included 351 on architectures which support it. 352 353config HAVE_ARCH_AUDITSYSCALL 354 bool 355 356config AUDITSYSCALL 357 def_bool y 358 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL 359 select FSNOTIFY 360 361source "kernel/irq/Kconfig" 362source "kernel/time/Kconfig" 363source "kernel/bpf/Kconfig" 364source "kernel/Kconfig.preempt" 365 366menu "CPU/Task time and stats accounting" 367 368config VIRT_CPU_ACCOUNTING 369 bool 370 371choice 372 prompt "Cputime accounting" 373 default VIRT_CPU_ACCOUNTING_GEN if NO_HZ_FULL 374 default TICK_CPU_ACCOUNTING 375 376# Kind of a stub config for the pure tick based cputime accounting 377config TICK_CPU_ACCOUNTING 378 bool "Simple tick based cputime accounting" 379 depends on !S390 && !NO_HZ_FULL 380 help 381 This is the basic tick based cputime accounting that maintains 382 statistics about user, system and idle time spent on per jiffies 383 granularity. 384 385 If unsure, say Y. 386 387config VIRT_CPU_ACCOUNTING_NATIVE 388 bool "Deterministic task and CPU time accounting" 389 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL 390 select VIRT_CPU_ACCOUNTING 391 help 392 Select this option to enable more accurate task and CPU time 393 accounting. This is done by reading a CPU counter on each 394 kernel entry and exit and on transitions within the kernel 395 between system, softirq and hardirq state, so there is a 396 small performance impact. In the case of s390 or IBM POWER > 5, 397 this also enables accounting of stolen time on logically-partitioned 398 systems. 399 400config VIRT_CPU_ACCOUNTING_GEN 401 bool "Full dynticks CPU time accounting" 402 depends on HAVE_CONTEXT_TRACKING_USER 403 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN 404 depends on GENERIC_CLOCKEVENTS 405 select VIRT_CPU_ACCOUNTING 406 select CONTEXT_TRACKING_USER 407 help 408 Select this option to enable task and CPU time accounting on full 409 dynticks systems. This accounting is implemented by watching every 410 kernel-user boundaries using the context tracking subsystem. 411 The accounting is thus performed at the expense of some significant 412 overhead. 413 414 For now this is only useful if you are working on the full 415 dynticks subsystem development. 416 417 If unsure, say N. 418 419endchoice 420 421config IRQ_TIME_ACCOUNTING 422 bool "Fine granularity task level IRQ time accounting" 423 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE 424 help 425 Select this option to enable fine granularity task irq time 426 accounting. This is done by reading a timestamp on each 427 transitions between softirq and hardirq state, so there can be a 428 small performance impact. 429 430 If in doubt, say N here. 431 432config HAVE_SCHED_AVG_IRQ 433 def_bool y 434 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING 435 depends on SMP 436 437config SCHED_HW_PRESSURE 438 bool 439 default y if ARM && ARM_CPU_TOPOLOGY 440 default y if ARM64 441 depends on SMP 442 depends on CPU_FREQ_THERMAL 443 help 444 Select this option to enable HW pressure accounting in the 445 scheduler. HW pressure is the value conveyed to the scheduler 446 that reflects the reduction in CPU compute capacity resulted from 447 HW throttling. HW throttling occurs when the performance of 448 a CPU is capped due to high operating temperatures as an example. 449 450 If selected, the scheduler will be able to balance tasks accordingly, 451 i.e. put less load on throttled CPUs than on non/less throttled ones. 452 453 This requires the architecture to implement 454 arch_update_hw_pressure() and arch_scale_thermal_pressure(). 455 456config BSD_PROCESS_ACCT 457 bool "BSD Process Accounting (DEPRECATED)" 458 depends on MULTIUSER 459 default n 460 help 461 If you say Y here, a user level program will be able to instruct the 462 kernel (via a special system call) to write process accounting 463 information to a file: whenever a process exits, information about 464 that process will be appended to the file by the kernel. The 465 information includes things such as creation time, owning user, 466 command name, memory usage, controlling terminal etc. (the complete 467 list is in the struct acct in <file:include/linux/acct.h>). It is 468 up to the user level program to do useful things with this 469 information. This mechanism is antiquated and has significant 470 scalability issues. You probably want to use eBPF instead. Say 471 N unless you really need this. 472 473config BSD_PROCESS_ACCT_V3 474 bool "BSD Process Accounting version 3 file format" 475 depends on BSD_PROCESS_ACCT 476 default n 477 help 478 If you say Y here, the process accounting information is written 479 in a new file format that also logs the process IDs of each 480 process and its parent. Note that this file format is incompatible 481 with previous v0/v1/v2 file formats, so you will need updated tools 482 for processing it. A preliminary version of these tools is available 483 at <http://www.gnu.org/software/acct/>. 484 485config TASKSTATS 486 bool "Export task/process statistics through netlink" 487 depends on NET 488 depends on MULTIUSER 489 default n 490 help 491 Export selected statistics for tasks/processes through the 492 generic netlink interface. Unlike BSD process accounting, the 493 statistics are available during the lifetime of tasks/processes as 494 responses to commands. Like BSD accounting, they are sent to user 495 space on task exit. 496 497 Say N if unsure. 498 499config TASK_DELAY_ACCT 500 bool "Enable per-task delay accounting" 501 depends on TASKSTATS 502 select SCHED_INFO 503 help 504 Collect information on time spent by a task waiting for system 505 resources like cpu, synchronous block I/O completion and swapping 506 in pages. Such statistics can help in setting a task's priorities 507 relative to other tasks for cpu, io, rss limits etc. 508 509 Say N if unsure. 510 511config TASK_XACCT 512 bool "Enable extended accounting over taskstats" 513 depends on TASKSTATS 514 help 515 Collect extended task accounting data and send the data 516 to userland for processing over the taskstats interface. 517 518 Say N if unsure. 519 520config TASK_IO_ACCOUNTING 521 bool "Enable per-task storage I/O accounting" 522 depends on TASK_XACCT 523 help 524 Collect information on the number of bytes of storage I/O which this 525 task has caused. 526 527 Say N if unsure. 528 529config PSI 530 bool "Pressure stall information tracking" 531 select KERNFS 532 help 533 Collect metrics that indicate how overcommitted the CPU, memory, 534 and IO capacity are in the system. 535 536 If you say Y here, the kernel will create /proc/pressure/ with the 537 pressure statistics files cpu, memory, and io. These will indicate 538 the share of walltime in which some or all tasks in the system are 539 delayed due to contention of the respective resource. 540 541 In kernels with cgroup support, cgroups (cgroup2 only) will 542 have cpu.pressure, memory.pressure, and io.pressure files, 543 which aggregate pressure stalls for the grouped tasks only. 544 545 For more details see Documentation/accounting/psi.rst. 546 547 Say N if unsure. 548 549config PSI_DEFAULT_DISABLED 550 bool "Require boot parameter to enable pressure stall information tracking" 551 default n 552 depends on PSI 553 help 554 If set, pressure stall information tracking will be disabled 555 per default but can be enabled through passing psi=1 on the 556 kernel commandline during boot. 557 558 This feature adds some code to the task wakeup and sleep 559 paths of the scheduler. The overhead is too low to affect 560 common scheduling-intense workloads in practice (such as 561 webservers, memcache), but it does show up in artificial 562 scheduler stress tests, such as hackbench. 563 564 If you are paranoid and not sure what the kernel will be 565 used for, say Y. 566 567 Say N if unsure. 568 569endmenu # "CPU/Task time and stats accounting" 570 571config CPU_ISOLATION 572 bool "CPU isolation" 573 depends on SMP 574 default y 575 help 576 Make sure that CPUs running critical tasks are not disturbed by 577 any source of "noise" such as unbound workqueues, timers, kthreads... 578 Unbound jobs get offloaded to housekeeping CPUs. This is driven by 579 the "isolcpus=" boot parameter. 580 581 Say Y if unsure. 582 583source "kernel/rcu/Kconfig" 584 585config IKCONFIG 586 tristate "Kernel .config support" 587 help 588 This option enables the complete Linux kernel ".config" file 589 contents to be saved in the kernel. It provides documentation 590 of which kernel options are used in a running kernel or in an 591 on-disk kernel. This information can be extracted from the kernel 592 image file with the script scripts/extract-ikconfig and used as 593 input to rebuild the current kernel or to build another kernel. 594 It can also be extracted from a running kernel by reading 595 /proc/config.gz if enabled (below). 596 597config IKCONFIG_PROC 598 bool "Enable access to .config through /proc/config.gz" 599 depends on IKCONFIG && PROC_FS 600 help 601 This option enables access to the kernel configuration file 602 through /proc/config.gz. 603 604config IKHEADERS 605 tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz" 606 depends on SYSFS 607 help 608 This option enables access to the in-kernel headers that are generated during 609 the build process. These can be used to build eBPF tracing programs, 610 or similar programs. If you build the headers as a module, a module called 611 kheaders.ko is built which can be loaded on-demand to get access to headers. 612 613config LOG_BUF_SHIFT 614 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 615 range 12 25 616 default 17 617 depends on PRINTK 618 help 619 Select the minimal kernel log buffer size as a power of 2. 620 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config 621 parameter, see below. Any higher size also might be forced 622 by "log_buf_len" boot parameter. 623 624 Examples: 625 17 => 128 KB 626 16 => 64 KB 627 15 => 32 KB 628 14 => 16 KB 629 13 => 8 KB 630 12 => 4 KB 631 632config LOG_CPU_MAX_BUF_SHIFT 633 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" 634 depends on SMP 635 range 0 21 636 default 0 if BASE_SMALL 637 default 12 638 depends on PRINTK 639 help 640 This option allows to increase the default ring buffer size 641 according to the number of CPUs. The value defines the contribution 642 of each CPU as a power of 2. The used space is typically only few 643 lines however it might be much more when problems are reported, 644 e.g. backtraces. 645 646 The increased size means that a new buffer has to be allocated and 647 the original static one is unused. It makes sense only on systems 648 with more CPUs. Therefore this value is used only when the sum of 649 contributions is greater than the half of the default kernel ring 650 buffer as defined by LOG_BUF_SHIFT. The default values are set 651 so that more than 16 CPUs are needed to trigger the allocation. 652 653 Also this option is ignored when "log_buf_len" kernel parameter is 654 used as it forces an exact (power of two) size of the ring buffer. 655 656 The number of possible CPUs is used for this computation ignoring 657 hotplugging making the computation optimal for the worst case 658 scenario while allowing a simple algorithm to be used from bootup. 659 660 Examples shift values and their meaning: 661 17 => 128 KB for each CPU 662 16 => 64 KB for each CPU 663 15 => 32 KB for each CPU 664 14 => 16 KB for each CPU 665 13 => 8 KB for each CPU 666 12 => 4 KB for each CPU 667 668config PRINTK_INDEX 669 bool "Printk indexing debugfs interface" 670 depends on PRINTK && DEBUG_FS 671 help 672 Add support for indexing of all printk formats known at compile time 673 at <debugfs>/printk/index/<module>. 674 675 This can be used as part of maintaining daemons which monitor 676 /dev/kmsg, as it permits auditing the printk formats present in a 677 kernel, allowing detection of cases where monitored printks are 678 changed or no longer present. 679 680 There is no additional runtime cost to printk with this enabled. 681 682# 683# Architectures with an unreliable sched_clock() should select this: 684# 685config HAVE_UNSTABLE_SCHED_CLOCK 686 bool 687 688config GENERIC_SCHED_CLOCK 689 bool 690 691menu "Scheduler features" 692 693config UCLAMP_TASK 694 bool "Enable utilization clamping for RT/FAIR tasks" 695 depends on CPU_FREQ_GOV_SCHEDUTIL 696 help 697 This feature enables the scheduler to track the clamped utilization 698 of each CPU based on RUNNABLE tasks scheduled on that CPU. 699 700 With this option, the user can specify the min and max CPU 701 utilization allowed for RUNNABLE tasks. The max utilization defines 702 the maximum frequency a task should use while the min utilization 703 defines the minimum frequency it should use. 704 705 Both min and max utilization clamp values are hints to the scheduler, 706 aiming at improving its frequency selection policy, but they do not 707 enforce or grant any specific bandwidth for tasks. 708 709 If in doubt, say N. 710 711config UCLAMP_BUCKETS_COUNT 712 int "Number of supported utilization clamp buckets" 713 range 5 20 714 default 5 715 depends on UCLAMP_TASK 716 help 717 Defines the number of clamp buckets to use. The range of each bucket 718 will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the 719 number of clamp buckets the finer their granularity and the higher 720 the precision of clamping aggregation and tracking at run-time. 721 722 For example, with the minimum configuration value we will have 5 723 clamp buckets tracking 20% utilization each. A 25% boosted tasks will 724 be refcounted in the [20..39]% bucket and will set the bucket clamp 725 effective value to 25%. 726 If a second 30% boosted task should be co-scheduled on the same CPU, 727 that task will be refcounted in the same bucket of the first task and 728 it will boost the bucket clamp effective value to 30%. 729 The clamp effective value of a bucket is reset to its nominal value 730 (20% in the example above) when there are no more tasks refcounted in 731 that bucket. 732 733 An additional boost/capping margin can be added to some tasks. In the 734 example above the 25% task will be boosted to 30% until it exits the 735 CPU. If that should be considered not acceptable on certain systems, 736 it's always possible to reduce the margin by increasing the number of 737 clamp buckets to trade off used memory for run-time tracking 738 precision. 739 740 If in doubt, use the default value. 741 742config SCHED_PROXY_EXEC 743 bool "Proxy Execution" 744 # Avoid some build failures w/ PREEMPT_RT until it can be fixed 745 depends on !PREEMPT_RT 746 # Not particularly useful until we get to multi-rq proxying 747 depends on EXPERT 748 help 749 This option enables proxy execution, a mechanism for mutex-owning 750 tasks to inherit the scheduling context of higher priority waiters. 751 752endmenu 753 754# 755# For architectures that support present-but-inaccessible (PROT_NONE) page 756# table entries detectable via pte_protnone() / pmd_protnone(): 757# 758config ARCH_HAS_PTE_PROTNONE 759 bool 760 761# 762# For architectures that want to enable the support for NUMA-affine scheduler 763# balancing logic: 764# 765config ARCH_SUPPORTS_NUMA_BALANCING 766 bool 767 768# 769# For architectures that prefer to flush all TLBs after a number of pages 770# are unmapped instead of sending one IPI per page to flush. The architecture 771# must provide guarantees on what happens if a clean TLB cache entry is 772# written after the unmap. Details are in mm/rmap.c near the check for 773# should_defer_flush. The architecture should also consider if the full flush 774# and the refill costs are offset by the savings of sending fewer IPIs. 775config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 776 bool 777 778config CC_HAS_INT128 779 def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT 780 781config CC_IMPLICIT_FALLTHROUGH 782 string 783 default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) 784 default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) 785 786config CC_MS_EXTENSIONS 787 string 788 default "-fms-anonymous-structs" if $(cc-option,-fms-anonymous-structs) 789 default "-fms-extensions" 790 791# Currently, disable gcc-10+ array-bounds globally. 792# It's still broken in gcc-13, so no upper bound yet. 793config GCC10_NO_ARRAY_BOUNDS 794 def_bool y 795 796config CC_NO_ARRAY_BOUNDS 797 bool 798 default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC10_NO_ARRAY_BOUNDS 799 800# Currently, disable -Wstringop-overflow for GCC globally. 801config GCC_NO_STRINGOP_OVERFLOW 802 def_bool y 803 804config CC_NO_STRINGOP_OVERFLOW 805 bool 806 default y if CC_IS_GCC && GCC_NO_STRINGOP_OVERFLOW 807 808config CC_STRINGOP_OVERFLOW 809 bool 810 default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW 811 812# 813# For architectures that know their GCC __int128 support is sound 814# 815config ARCH_SUPPORTS_INT128 816 bool 817 818# For architectures that (ab)use NUMA to represent different memory regions 819# all cpu-local but of different latencies, such as SuperH. 820# 821config ARCH_WANT_NUMA_VARIABLE_LOCALITY 822 bool 823 824config NUMA_BALANCING 825 bool "Memory placement aware NUMA scheduler" 826 depends on ARCH_SUPPORTS_NUMA_BALANCING 827 depends on ARCH_HAS_PTE_PROTNONE 828 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY 829 depends on SMP && NUMA_MIGRATION && !PREEMPT_RT 830 help 831 This option adds support for automatic NUMA aware memory/task placement. 832 The mechanism is quite primitive and is based on migrating memory when 833 it has references to the node the task is running on. 834 835 This system will be inactive on UMA systems. 836 837config SCHED_CACHE 838 bool "Cache aware load balance" 839 default y 840 depends on SMP 841 help 842 When enabled, the scheduler will attempt to aggregate tasks from 843 the same process onto a single Last Level Cache (LLC) domain when 844 possible. This improves cache locality by keeping tasks that share 845 resources within the same cache domain, reducing cache misses and 846 lowering data access latency. 847 848config NUMA_BALANCING_DEFAULT_ENABLED 849 bool "Automatically enable NUMA aware memory/task placement" 850 default y 851 depends on NUMA_BALANCING 852 help 853 If set, automatic NUMA balancing will be enabled if running on a NUMA 854 machine. 855 856config SLAB_OBJ_EXT 857 bool 858 859menuconfig CGROUPS 860 bool "Control Group support" 861 select KERNFS 862 help 863 This option adds support for grouping sets of processes together, for 864 use with process control subsystems such as Cpusets, CFS, memory 865 controls or device isolation. 866 See 867 - Documentation/scheduler/sched-design-CFS.rst (CFS) 868 - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation 869 and resource control) 870 871 Say N if unsure. 872 873if CGROUPS 874 875config PAGE_COUNTER 876 bool 877 878config CGROUP_FAVOR_DYNMODS 879 bool "Favor dynamic modification latency reduction by default" 880 help 881 This option enables the "favordynmods" mount option by default 882 which reduces the latencies of dynamic cgroup modifications such 883 as task migrations and controller on/offs at the cost of making 884 hot path operations such as forks and exits more expensive. 885 886 Say N if unsure. 887 888config MEMCG 889 bool "Memory controller" 890 select PAGE_COUNTER 891 select EVENTFD 892 select SLAB_OBJ_EXT 893 select VM_EVENT_COUNTERS 894 help 895 Provides control over the memory footprint of tasks in a cgroup. 896 897config MEMCG_NMI_UNSAFE 898 bool 899 depends on MEMCG 900 depends on HAVE_NMI 901 depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && !ARCH_HAVE_NMI_SAFE_CMPXCHG 902 default y 903 904config MEMCG_NMI_SAFETY_REQUIRES_ATOMIC 905 bool 906 depends on MEMCG 907 depends on HAVE_NMI 908 depends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && ARCH_HAVE_NMI_SAFE_CMPXCHG 909 default y 910 911config MEMCG_V1 912 bool "Legacy cgroup v1 memory controller" 913 depends on MEMCG 914 default n 915 help 916 Legacy cgroup v1 memory controller which has been deprecated by 917 cgroup v2 implementation. The v1 is there for legacy applications 918 which haven't migrated to the new cgroup v2 interface yet. If you 919 do not have any such application then you are completely fine leaving 920 this option disabled. 921 922 Please note that feature set of the legacy memory controller is likely 923 going to shrink due to deprecation process. New deployments with v1 924 controller are highly discouraged. 925 926 Say N if unsure. 927 928config BLK_CGROUP 929 bool "IO controller" 930 depends on BLOCK 931 default n 932 help 933 Generic block IO controller cgroup interface. This is the common 934 cgroup interface which should be used by various IO controlling 935 policies. 936 937 Currently, CFQ IO scheduler uses it to recognize task groups and 938 control disk bandwidth allocation (proportional time slice allocation) 939 to such task groups. It is also used by bio throttling logic in 940 block layer to implement upper limit in IO rates on a device. 941 942 This option only enables generic Block IO controller infrastructure. 943 One needs to also enable actual IO controlling logic/policy. For 944 enabling proportional weight division of disk bandwidth in CFQ, set 945 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set 946 CONFIG_BLK_DEV_THROTTLING=y. 947 948 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information. 949 950config CGROUP_WRITEBACK 951 bool 952 depends on MEMCG && BLK_CGROUP 953 default y 954 955menuconfig CGROUP_SCHED 956 bool "CPU controller" 957 default n 958 help 959 This feature lets CPU scheduler recognize task groups and control CPU 960 bandwidth allocation to such task groups. It uses cgroups to group 961 tasks. 962 963if CGROUP_SCHED 964config GROUP_SCHED_WEIGHT 965 def_bool n 966 967config GROUP_SCHED_BANDWIDTH 968 def_bool n 969 970config FAIR_GROUP_SCHED 971 bool "Group scheduling for SCHED_OTHER" 972 depends on CGROUP_SCHED 973 select GROUP_SCHED_WEIGHT 974 default CGROUP_SCHED 975 976config CFS_BANDWIDTH 977 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" 978 depends on FAIR_GROUP_SCHED 979 select GROUP_SCHED_BANDWIDTH 980 default n 981 help 982 This option allows users to define CPU bandwidth rates (limits) for 983 tasks running within the fair group scheduler. Groups with no limit 984 set are considered to be unconstrained and will run with no 985 restriction. 986 See Documentation/scheduler/sched-bwc.rst for more information. 987 988config RT_GROUP_SCHED 989 bool "Group scheduling for SCHED_RR/FIFO" 990 depends on CGROUP_SCHED 991 default n 992 help 993 This feature lets you explicitly allocate real CPU bandwidth 994 to task groups. If enabled, it will also make it impossible to 995 schedule realtime tasks for non-root users until you allocate 996 realtime bandwidth for them. 997 See Documentation/scheduler/sched-rt-group.rst for more information. 998 999config RT_GROUP_SCHED_DEFAULT_DISABLED 1000 bool "Require boot parameter to enable group scheduling for SCHED_RR/FIFO" 1001 depends on RT_GROUP_SCHED 1002 default n 1003 help 1004 When set, the RT group scheduling is disabled by default. The option 1005 is in inverted form so that mere RT_GROUP_SCHED enables the group 1006 scheduling. 1007 1008 Say N if unsure. 1009 1010config EXT_GROUP_SCHED 1011 bool 1012 depends on SCHED_CLASS_EXT && CGROUP_SCHED 1013 select GROUP_SCHED_WEIGHT 1014 select GROUP_SCHED_BANDWIDTH 1015 default y 1016 1017endif #CGROUP_SCHED 1018 1019config EXT_SUB_SCHED 1020 def_bool y 1021 depends on SCHED_CLASS_EXT && CGROUPS 1022 1023config SCHED_MM_CID 1024 def_bool y 1025 depends on SMP && RSEQ 1026 1027config UCLAMP_TASK_GROUP 1028 bool "Utilization clamping per group of tasks" 1029 depends on CGROUP_SCHED 1030 depends on UCLAMP_TASK 1031 default n 1032 help 1033 This feature enables the scheduler to track the clamped utilization 1034 of each CPU based on RUNNABLE tasks currently scheduled on that CPU. 1035 1036 When this option is enabled, the user can specify a min and max 1037 CPU bandwidth which is allowed for each single task in a group. 1038 The max bandwidth allows to clamp the maximum frequency a task 1039 can use, while the min bandwidth allows to define a minimum 1040 frequency a task will always use. 1041 1042 When task group based utilization clamping is enabled, an eventually 1043 specified task-specific clamp value is constrained by the cgroup 1044 specified clamp value. Both minimum and maximum task clamping cannot 1045 be bigger than the corresponding clamping defined at task group level. 1046 1047 If in doubt, say N. 1048 1049config CGROUP_PIDS 1050 bool "PIDs controller" 1051 help 1052 Provides enforcement of process number limits in the scope of a 1053 cgroup. Any attempt to fork more processes than is allowed in the 1054 cgroup will fail. PIDs are fundamentally a global resource because it 1055 is fairly trivial to reach PID exhaustion before you reach even a 1056 conservative kmemcg limit. As a result, it is possible to grind a 1057 system to halt without being limited by other cgroup policies. The 1058 PIDs controller is designed to stop this from happening. 1059 1060 It should be noted that organisational operations (such as attaching 1061 to a cgroup hierarchy) will *not* be blocked by the PIDs controller, 1062 since the PIDs limit only affects a process's ability to fork, not to 1063 attach to a cgroup. 1064 1065config CGROUP_RDMA 1066 bool "RDMA controller" 1067 help 1068 Provides enforcement of RDMA resources defined by IB stack. 1069 It is fairly easy for consumers to exhaust RDMA resources, which 1070 can result into resource unavailability to other consumers. 1071 RDMA controller is designed to stop this from happening. 1072 Attaching processes with active RDMA resources to the cgroup 1073 hierarchy is allowed even if can cross the hierarchy's limit. 1074 1075config CGROUP_DMEM 1076 bool "Device memory controller (DMEM)" 1077 select PAGE_COUNTER 1078 help 1079 The DMEM controller allows compatible devices to restrict device 1080 memory usage based on the cgroup hierarchy. 1081 1082 As an example, it allows you to restrict VRAM usage for applications 1083 in the DRM subsystem. 1084 1085config CGROUP_FREEZER 1086 bool "Freezer controller" 1087 help 1088 Provides a way to freeze and unfreeze all tasks in a 1089 cgroup. 1090 1091 This option affects the ORIGINAL cgroup interface. The cgroup2 memory 1092 controller includes important in-kernel memory consumers per default. 1093 1094 If you're using cgroup2, say N. 1095 1096config CGROUP_HUGETLB 1097 bool "HugeTLB controller" 1098 depends on HUGETLB_PAGE 1099 select PAGE_COUNTER 1100 default n 1101 help 1102 Provides a cgroup controller for HugeTLB pages. 1103 When you enable this, you can put a per cgroup limit on HugeTLB usage. 1104 The limit is enforced during page fault. Since HugeTLB doesn't 1105 support page reclaim, enforcing the limit at page fault time implies 1106 that, the application will get SIGBUS signal if it tries to access 1107 HugeTLB pages beyond its limit. This requires the application to know 1108 beforehand how much HugeTLB pages it would require for its use. The 1109 control group is tracked in the third page lru pointer. This means 1110 that we cannot use the controller with huge page less than 3 pages. 1111 1112config CPUSETS 1113 bool "Cpuset controller" 1114 depends on SMP 1115 select UNION_FIND 1116 select CPU_ISOLATION 1117 help 1118 This option will let you create and manage CPUSETs which 1119 allow dynamically partitioning a system into sets of CPUs and 1120 Memory Nodes and assigning tasks to run only within those sets. 1121 This is primarily useful on large SMP or NUMA systems. 1122 1123 Say N if unsure. 1124 1125config CPUSETS_V1 1126 bool "Legacy cgroup v1 cpusets controller" 1127 depends on CPUSETS 1128 default n 1129 help 1130 Legacy cgroup v1 cpusets controller which has been deprecated by 1131 cgroup v2 implementation. The v1 is there for legacy applications 1132 which haven't migrated to the new cgroup v2 interface yet. Legacy 1133 interface includes cpuset filesystem and /proc/<pid>/cpuset. If you 1134 do not have any such application then you are completely fine leaving 1135 this option disabled. 1136 1137 Say N if unsure. 1138 1139config PROC_PID_CPUSET 1140 bool "Include legacy /proc/<pid>/cpuset file" 1141 depends on CPUSETS_V1 1142 default y 1143 1144config CGROUP_DEVICE 1145 bool "Device controller" 1146 help 1147 Provides a cgroup controller implementing whitelists for 1148 devices which a process in the cgroup can mknod or open. 1149 1150config CGROUP_CPUACCT 1151 bool "Simple CPU accounting controller" 1152 help 1153 Provides a simple controller for monitoring the 1154 total CPU consumed by the tasks in a cgroup. 1155 1156config CGROUP_PERF 1157 bool "Perf controller" 1158 depends on PERF_EVENTS 1159 help 1160 This option extends the perf per-cpu mode to restrict monitoring 1161 to threads which belong to the cgroup specified and run on the 1162 designated cpu. Or this can be used to have cgroup ID in samples 1163 so that it can monitor performance events among cgroups. 1164 1165 Say N if unsure. 1166 1167config CGROUP_BPF 1168 bool "Support for eBPF programs attached to cgroups" 1169 depends on BPF_SYSCALL 1170 select SOCK_CGROUP_DATA 1171 help 1172 Allow attaching eBPF programs to a cgroup using the bpf(2) 1173 syscall command BPF_PROG_ATTACH. 1174 1175 In which context these programs are accessed depends on the type 1176 of attachment. For instance, programs that are attached using 1177 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of 1178 inet sockets. 1179 1180config CGROUP_MISC 1181 bool "Misc resource controller" 1182 default n 1183 help 1184 Provides a controller for miscellaneous resources on a host. 1185 1186 Miscellaneous scalar resources are the resources on the host system 1187 which cannot be abstracted like the other cgroups. This controller 1188 tracks and limits the miscellaneous resources used by a process 1189 attached to a cgroup hierarchy. 1190 1191 For more information, please check misc cgroup section in 1192 /Documentation/admin-guide/cgroup-v2.rst. 1193 1194config CGROUP_DEBUG 1195 bool "Debug controller" 1196 default n 1197 depends on DEBUG_KERNEL 1198 help 1199 This option enables a simple controller that exports 1200 debugging information about the cgroups framework. This 1201 controller is for control cgroup debugging only. Its 1202 interfaces are not stable. 1203 1204 Say N. 1205 1206config SOCK_CGROUP_DATA 1207 bool 1208 default n 1209 1210endif # CGROUPS 1211 1212menuconfig NAMESPACES 1213 bool "Namespaces support" if EXPERT 1214 depends on MULTIUSER 1215 default !EXPERT 1216 help 1217 Provides the way to make tasks work with different objects using 1218 the same id. For example same IPC id may refer to different objects 1219 or same user id or pid may refer to different tasks when used in 1220 different namespaces. 1221 1222if NAMESPACES 1223 1224config UTS_NS 1225 bool "UTS namespace" 1226 default y 1227 help 1228 In this namespace tasks see different info provided with the 1229 uname() system call 1230 1231config TIME_NS 1232 bool "TIME namespace" 1233 default y 1234 help 1235 In this namespace boottime and monotonic clocks can be set. 1236 The time will keep going with the same pace. 1237 1238config TIME_NS_VDSO 1239 def_bool TIME_NS && GENERIC_GETTIMEOFDAY 1240 1241config IPC_NS 1242 bool "IPC namespace" 1243 depends on (SYSVIPC || POSIX_MQUEUE) 1244 default y 1245 help 1246 In this namespace tasks work with IPC ids which correspond to 1247 different IPC objects in different namespaces. 1248 1249config USER_NS 1250 bool "User namespace" 1251 default n 1252 help 1253 This allows containers, i.e. vservers, to use user namespaces 1254 to provide different user info for different servers. 1255 1256 When user namespaces are enabled in the kernel it is 1257 recommended that the MEMCG option also be enabled and that 1258 user-space use the memory control groups to limit the amount 1259 of memory a memory unprivileged users can use. 1260 1261 If unsure, say N. 1262 1263config USER_NS_MAP_KUNIT_TEST 1264 tristate "KUint test for user namespace map insertion" if !KUNIT_ALL_TESTS 1265 depends on USER_NS && KUNIT 1266 default KUNIT_ALL_TESTS 1267 help 1268 This builds the KUnit test for user namespace uid/gid map insertion. 1269 It validates map insertion, limits, dynamic allocation of the 1270 extended extents array, and mapping sorting functions. 1271 1272 If unsure, say N. 1273 1274config PID_NS 1275 bool "PID Namespaces" 1276 default y 1277 help 1278 Support process id namespaces. This allows having multiple 1279 processes with the same pid as long as they are in different 1280 pid namespaces. This is a building block of containers. 1281 1282config NET_NS 1283 bool "Network namespace" 1284 depends on NET 1285 default y 1286 help 1287 Allow user space to create what appear to be multiple instances 1288 of the network stack. 1289 1290endif # NAMESPACES 1291 1292config CHECKPOINT_RESTORE 1293 bool "Checkpoint/restore support" 1294 depends on PROC_FS 1295 select PROC_CHILDREN 1296 select KCMP 1297 default n 1298 help 1299 Enables additional kernel features in a sake of checkpoint/restore. 1300 In particular it adds auxiliary prctl codes to setup process text, 1301 data and heap segment sizes, and a few additional /proc filesystem 1302 entries. 1303 1304 If unsure, say N here. 1305 1306config SCHED_AUTOGROUP 1307 bool "Automatic process group scheduling" 1308 select CGROUPS 1309 select CGROUP_SCHED 1310 select FAIR_GROUP_SCHED 1311 help 1312 This option optimizes the scheduler for common desktop workloads by 1313 automatically creating and populating task groups. This separation 1314 of workloads isolates aggressive CPU burners (like build jobs) from 1315 desktop applications. Task group autogeneration is currently based 1316 upon task session. 1317 1318config RELAY 1319 bool "Kernel->user space relay support (formerly relayfs)" 1320 select IRQ_WORK 1321 help 1322 This option enables support for relay interface support in 1323 certain file systems (such as debugfs). 1324 It is designed to provide an efficient mechanism for tools and 1325 facilities to relay large amounts of data from kernel space to 1326 user space. 1327 1328 If unsure, say N. 1329 1330config BLK_DEV_INITRD 1331 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 1332 help 1333 The initial RAM filesystem is a ramfs which is loaded by the 1334 boot loader (loadlin or lilo) and that is mounted as root 1335 before the normal boot procedure. It is typically used to 1336 load modules needed to mount the "real" root file system, 1337 etc. See <file:Documentation/admin-guide/initrd.rst> for details. 1338 1339 If RAM disk support (BLK_DEV_RAM) is also included, this 1340 also enables initial RAM disk (initrd) support and adds 1341 15 Kbytes (more on some other architectures) to the kernel size. 1342 1343 If unsure say Y. 1344 1345if BLK_DEV_INITRD 1346 1347source "usr/Kconfig" 1348 1349endif 1350 1351config BOOT_CONFIG 1352 bool "Boot config support" 1353 select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED 1354 help 1355 Extra boot config allows system admin to pass a config file as 1356 complemental extension of kernel cmdline when booting. 1357 The boot config file must be attached at the end of initramfs 1358 with checksum, size and magic word. 1359 See <file:Documentation/admin-guide/bootconfig.rst> for details. 1360 1361 If unsure, say Y. 1362 1363config BOOT_CONFIG_FORCE 1364 bool "Force unconditional bootconfig processing" 1365 depends on BOOT_CONFIG 1366 default y if BOOT_CONFIG_EMBED 1367 help 1368 With this Kconfig option set, BOOT_CONFIG processing is carried 1369 out even when the "bootconfig" kernel-boot parameter is omitted. 1370 In fact, with this Kconfig option set, there is no way to 1371 make the kernel ignore the BOOT_CONFIG-supplied kernel-boot 1372 parameters. 1373 1374 If unsure, say N. 1375 1376config BOOT_CONFIG_EMBED 1377 bool "Embed bootconfig file in the kernel" 1378 depends on BOOT_CONFIG 1379 help 1380 Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the 1381 kernel. Usually, the bootconfig file is loaded with the initrd 1382 image. But if the system doesn't support initrd, this option will 1383 help you by embedding a bootconfig file while building the kernel. 1384 1385 If unsure, say N. 1386 1387config BOOT_CONFIG_EMBED_FILE 1388 string "Embedded bootconfig file path" 1389 depends on BOOT_CONFIG_EMBED 1390 help 1391 Specify a bootconfig file which will be embedded to the kernel. 1392 This bootconfig will be used if there is no initrd or no other 1393 bootconfig in the initrd. 1394 1395config ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG 1396 bool 1397 help 1398 Silent symbol; no C code reads it directly. Architectures 1399 select it once their setup_arch() calls 1400 xbc_prepend_embedded_cmdline() before parse_early_param(). 1401 Its only role is to gate the user-visible 1402 CMDLINE_FROM_BOOTCONFIG option per-arch, the same 1403 ARCH_SUPPORTS_* idiom used by ARCH_SUPPORTS_CFI, etc. 1404 1405config CMDLINE_FROM_BOOTCONFIG 1406 bool "Render embedded bootconfig as kernel cmdline at build time" 1407 depends on BOOT_CONFIG_EMBED_FILE != "" 1408 depends on ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG 1409 depends on CMDLINE = "" 1410 default n 1411 help 1412 Render the "kernel" subtree of the embedded bootconfig file into a 1413 flat cmdline string at kernel build time and prepend it to 1414 boot_command_line during early architecture setup. This makes 1415 early_param() handlers (e.g. mem=, earlycon=, loglevel=) see the 1416 values supplied via the embedded bootconfig. 1417 1418 The runtime bootconfig parser is unaffected, so tree-structured 1419 consumers such as ftrace boot-time tracing keep working. 1420 1421 Note: when an initrd also carries a bootconfig, its "kernel" 1422 subtree is still parsed at runtime, but the embedded "kernel" 1423 keys remain in boot_command_line for parse_early_param() and 1424 end up later than the initrd keys in saved_command_line, so 1425 parse_args() last-wins favors the embedded values. If you need 1426 initrd to override embedded kernel.* keys, leave this option 1427 off. 1428 1429 If unsure, say N. 1430 1431config CMDLINE_LOG_WRAP_IDEAL_LEN 1432 int "Length to try to wrap the cmdline when logged at boot" 1433 default 1021 1434 range 0 1021 1435 help 1436 At boot time, the kernel command line is logged to the console. 1437 The log message will start with the prefix "Kernel command line: ". 1438 The log message will attempt to be wrapped (split into multiple log 1439 messages) at spaces based on CMDLINE_LOG_WRAP_IDEAL_LEN characters. 1440 If wrapping happens, each log message will start with the prefix and 1441 all but the last message will end with " \". Messages may exceed the 1442 ideal length if a place to wrap isn't found before the specified 1443 number of characters. 1444 1445 A value of 0 disables wrapping, though be warned that the maximum 1446 length of a log message (1021 characters) may cause the cmdline to 1447 be truncated. 1448 1449config INITRAMFS_PRESERVE_MTIME 1450 bool "Preserve cpio archive mtimes in initramfs" 1451 depends on BLK_DEV_INITRD 1452 default y 1453 help 1454 Each entry in an initramfs cpio archive carries an mtime value. When 1455 enabled, extracted cpio items take this mtime, with directory mtime 1456 setting deferred until after creation of any child entries. 1457 1458 If unsure, say Y. 1459 1460config INITRAMFS_TEST 1461 bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS 1462 depends on BLK_DEV_INITRD && KUNIT=y 1463 default KUNIT_ALL_TESTS 1464 help 1465 Build KUnit tests for initramfs. See Documentation/dev-tools/kunit 1466 1467choice 1468 prompt "Compiler optimization level" 1469 default CC_OPTIMIZE_FOR_PERFORMANCE 1470 1471config CC_OPTIMIZE_FOR_PERFORMANCE 1472 bool "Optimize for performance (-O2)" 1473 help 1474 This is the default optimization level for the kernel, building 1475 with the "-O2" compiler flag for best performance and most 1476 helpful compile-time warnings. 1477 1478config CC_OPTIMIZE_FOR_SIZE 1479 bool "Optimize for size (-Os)" 1480 help 1481 Choosing this option will pass "-Os" to your compiler resulting 1482 in a smaller kernel. 1483 1484endchoice 1485 1486config HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1487 bool 1488 help 1489 This requires that the arch annotates or otherwise protects 1490 its external entry points from being discarded. Linker scripts 1491 must also merge .text.*, .data.*, and .bss.* correctly into 1492 output sections. Care must be taken not to pull in unrelated 1493 sections (e.g., '.text.init'). Typically '.' in section names 1494 is used to distinguish them from label names / C identifiers. 1495 1496config LD_DEAD_CODE_DATA_ELIMINATION 1497 bool "Dead code and data elimination (EXPERIMENTAL)" 1498 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION 1499 depends on EXPERT 1500 depends on $(cc-option,-ffunction-sections -fdata-sections) 1501 depends on $(ld-option,--gc-sections) 1502 help 1503 Enable this if you want to do dead code and data elimination with 1504 the linker by compiling with -ffunction-sections -fdata-sections, 1505 and linking with --gc-sections. 1506 1507 This can reduce on disk and in-memory size of the kernel 1508 code and static data, particularly for small configs and 1509 on small systems. This has the possibility of introducing 1510 silently broken kernel if the required annotations are not 1511 present. This option is not well tested yet, so use at your 1512 own risk. 1513 1514config LD_ORPHAN_WARN 1515 def_bool y 1516 depends on ARCH_WANT_LD_ORPHAN_WARN 1517 depends on $(ld-option,--orphan-handling=warn) 1518 depends on $(ld-option,--orphan-handling=error) 1519 1520config LD_ORPHAN_WARN_LEVEL 1521 string 1522 depends on LD_ORPHAN_WARN 1523 default "error" if WERROR 1524 default "warn" 1525 1526config HAVE_UID16 1527 bool 1528 1529config SYSCTL_EXCEPTION_TRACE 1530 bool 1531 help 1532 Enable support for /proc/sys/debug/exception-trace. 1533 1534config SYSCTL_ARCH_UNALIGN_NO_WARN 1535 bool 1536 help 1537 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap 1538 Allows arch to define/use @no_unaligned_warning to possibly warn 1539 about unaligned access emulation going on under the hood. 1540 1541config SYSCTL_ARCH_UNALIGN_ALLOW 1542 bool 1543 help 1544 Enable support for /proc/sys/kernel/unaligned-trap 1545 Allows arches to define/use @unaligned_enabled to runtime toggle 1546 the unaligned access emulation. 1547 see arch/parisc/kernel/unaligned.c for reference 1548 1549config SYSFS_SYSCALL 1550 bool "Sysfs syscall support" 1551 default n 1552 help 1553 sys_sysfs is an obsolete system call no longer supported in libc. 1554 Note that disabling this option is more secure but might break 1555 compatibility with some systems. 1556 1557 If unsure say N here. 1558 1559config HAVE_PCSPKR_PLATFORM 1560 bool 1561 1562menuconfig EXPERT 1563 bool "Configure standard kernel features (expert users)" 1564 # Unhide debug options, to make the on-by-default options visible 1565 select DEBUG_KERNEL 1566 help 1567 This option allows certain base kernel options and settings 1568 to be disabled or tweaked. This is for specialized 1569 environments which can tolerate a "non-standard" kernel. 1570 Only use this if you really know what you are doing. 1571 1572config UID16 1573 bool "Enable 16-bit UID system calls" if EXPERT 1574 depends on HAVE_UID16 && MULTIUSER 1575 default y 1576 help 1577 This enables the legacy 16-bit UID syscall wrappers. 1578 1579config MULTIUSER 1580 bool "Multiple users, groups and capabilities support" if EXPERT 1581 default y 1582 help 1583 This option enables support for non-root users, groups and 1584 capabilities. 1585 1586 If you say N here, all processes will run with UID 0, GID 0, and all 1587 possible capabilities. Saying N here also compiles out support for 1588 system calls related to UIDs, GIDs, and capabilities, such as setuid, 1589 setgid, and capset. 1590 1591 If unsure, say Y here. 1592 1593config SGETMASK_SYSCALL 1594 bool "sgetmask/ssetmask syscalls support" if EXPERT 1595 default PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH 1596 help 1597 sys_sgetmask and sys_ssetmask are obsolete system calls 1598 no longer supported in libc but still enabled by default in some 1599 architectures. 1600 1601 If unsure, leave the default option here. 1602 1603config FHANDLE 1604 bool "open by fhandle syscalls" if EXPERT 1605 select EXPORTFS 1606 default y 1607 help 1608 If you say Y here, a user level program will be able to map 1609 file names to handle and then later use the handle for 1610 different file system operations. This is useful in implementing 1611 userspace file servers, which now track files using handles instead 1612 of names. The handle would remain the same even if file names 1613 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) 1614 syscalls. 1615 1616config POSIX_TIMERS 1617 bool "Posix Clocks & timers" if EXPERT 1618 default y 1619 help 1620 This includes native support for POSIX timers to the kernel. 1621 Some embedded systems have no use for them and therefore they 1622 can be configured out to reduce the size of the kernel image. 1623 1624 When this option is disabled, the following syscalls won't be 1625 available: timer_create, timer_gettime: timer_getoverrun, 1626 timer_settime, timer_delete, clock_adjtime, getitimer, 1627 setitimer, alarm. Furthermore, the clock_settime, clock_gettime, 1628 clock_getres and clock_nanosleep syscalls will be limited to 1629 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. 1630 1631 If unsure say y. 1632 1633config PRINTK 1634 default y 1635 bool "Enable support for printk" if EXPERT 1636 select IRQ_WORK 1637 help 1638 This option enables normal printk support. Removing it 1639 eliminates most of the message strings from the kernel image 1640 and makes the kernel more or less silent. As this makes it 1641 very difficult to diagnose system problems, saying N here is 1642 strongly discouraged. 1643 1644config PRINTK_RINGBUFFER_KUNIT_TEST 1645 tristate "KUnit Test for the printk ringbuffer" if !KUNIT_ALL_TESTS 1646 depends on PRINTK && KUNIT 1647 default KUNIT_ALL_TESTS 1648 help 1649 This builds the printk ringbuffer KUnit test suite. 1650 1651 For more information on KUnit and unit tests in general, please refer 1652 to the KUnit documentation. 1653 1654 If unsure, say N. 1655 1656config BUG 1657 bool "BUG() support" if EXPERT 1658 default y 1659 help 1660 Disabling this option eliminates support for BUG and WARN, reducing 1661 the size of your kernel image and potentially quietly ignoring 1662 numerous fatal conditions. You should only consider disabling this 1663 option for embedded systems with no facilities for reporting errors. 1664 Just say Y. 1665 1666config ELF_CORE 1667 depends on COREDUMP 1668 default y 1669 bool "Enable ELF core dumps" if EXPERT 1670 help 1671 Enable support for generating core dumps. Disabling saves about 4k. 1672 1673 1674config PCSPKR_PLATFORM 1675 bool "Enable PC-Speaker support" if EXPERT 1676 depends on HAVE_PCSPKR_PLATFORM 1677 select I8253_LOCK 1678 default y 1679 help 1680 This option allows to disable the internal PC-Speaker 1681 support, saving some memory. 1682 1683config BASE_SMALL 1684 bool "Enable smaller-sized data structures for core" if EXPERT 1685 help 1686 Enabling this option reduces the size of miscellaneous core 1687 kernel data structures. This saves memory on small machines, 1688 but may reduce performance. 1689 1690config FUTEX 1691 bool "Enable futex support" if EXPERT 1692 depends on !(SPARC32 && SMP) 1693 default y 1694 imply RT_MUTEXES 1695 help 1696 Disabling this option will cause the kernel to be built without 1697 support for "fast userspace mutexes". The resulting kernel may not 1698 run glibc-based applications correctly. 1699 1700config FUTEX_PI 1701 bool 1702 depends on FUTEX && RT_MUTEXES 1703 default y 1704 1705config FUTEX_PRIVATE_HASH 1706 bool 1707 depends on FUTEX && !BASE_SMALL && MMU 1708 default y 1709 1710config FUTEX_MPOL 1711 bool 1712 depends on FUTEX && NUMA 1713 default y 1714 1715config HAVE_FUTEX_ROBUST_UNLOCK 1716 bool 1717 1718config FUTEX_ROBUST_UNLOCK 1719 def_bool FUTEX && GENERIC_IRQ_ENTRY && RSEQ && HAVE_FUTEX_ROBUST_UNLOCK 1720 1721config EPOLL 1722 bool "Enable eventpoll support" if EXPERT 1723 default y 1724 help 1725 Disabling this option will cause the kernel to be built without 1726 support for epoll family of system calls. 1727 1728config SIGNALFD 1729 bool "Enable signalfd() system call" if EXPERT 1730 default y 1731 help 1732 Enable the signalfd() system call that allows to receive signals 1733 on a file descriptor. 1734 1735 If unsure, say Y. 1736 1737config TIMERFD 1738 bool "Enable timerfd() system call" if EXPERT 1739 default y 1740 help 1741 Enable the timerfd() system call that allows to receive timer 1742 events on a file descriptor. 1743 1744 If unsure, say Y. 1745 1746config EVENTFD 1747 bool "Enable eventfd() system call" if EXPERT 1748 default y 1749 help 1750 Enable the eventfd() system call that allows to receive both 1751 kernel notification (ie. KAIO) or userspace notifications. 1752 1753 If unsure, say Y. 1754 1755config SHMEM 1756 bool "Use full shmem filesystem" if EXPERT 1757 default y 1758 depends on MMU 1759 help 1760 The shmem is an internal filesystem used to manage shared memory. 1761 It is backed by swap and manages resource limits. It is also exported 1762 to userspace as tmpfs if TMPFS is enabled. Disabling this 1763 option replaces shmem and tmpfs with the much simpler ramfs code, 1764 which may be appropriate on small systems without swap. 1765 1766config AIO 1767 bool "Enable AIO support" if EXPERT 1768 default y 1769 help 1770 This option enables POSIX asynchronous I/O which may by used 1771 by some high performance threaded applications. Disabling 1772 this option saves about 7k. 1773 1774config IO_URING 1775 bool "Enable IO uring support" if EXPERT 1776 select IO_WQ 1777 default y 1778 help 1779 This option enables support for the io_uring interface, enabling 1780 applications to submit and complete IO through submission and 1781 completion rings that are shared between the kernel and application. 1782 1783config GCOV_PROFILE_URING 1784 bool "Enable GCOV profiling on the io_uring subsystem" 1785 depends on IO_URING && GCOV_KERNEL 1786 help 1787 Enable GCOV profiling on the io_uring subsystem, to facilitate 1788 code coverage testing. 1789 1790 If unsure, say N. 1791 1792 Note that this will have a negative impact on the performance of 1793 the io_uring subsystem, hence this should only be enabled for 1794 specific test purposes. 1795 1796config IO_URING_MOCK_FILE 1797 tristate "Enable io_uring mock files (Experimental)" if EXPERT 1798 default n 1799 depends on IO_URING 1800 help 1801 Enable mock files for io_uring subsystem testing. The ABI might 1802 still change, so it's still experimental and should only be enabled 1803 for specific test purposes. 1804 1805 If unsure, say N. 1806 1807config ADVISE_SYSCALLS 1808 bool "Enable madvise/fadvise syscalls" if EXPERT 1809 default y 1810 help 1811 This option enables the madvise and fadvise syscalls, used by 1812 applications to advise the kernel about their future memory or file 1813 usage, improving performance. If building an embedded system where no 1814 applications use these syscalls, you can disable this option to save 1815 space. 1816 1817config MEMBARRIER 1818 bool "Enable membarrier() system call" if EXPERT 1819 default y 1820 help 1821 Enable the membarrier() system call that allows issuing memory 1822 barriers across all running threads, which can be used to distribute 1823 the cost of user-space memory barriers asymmetrically by transforming 1824 pairs of memory barriers into pairs consisting of membarrier() and a 1825 compiler barrier. 1826 1827 If unsure, say Y. 1828 1829config KCMP 1830 bool "Enable kcmp() system call" if EXPERT 1831 help 1832 Enable the kernel resource comparison system call. It provides 1833 user-space with the ability to compare two processes to see if they 1834 share a common resource, such as a file descriptor or even virtual 1835 memory space. 1836 1837 If unsure, say N. 1838 1839config RSEQ 1840 bool "Enable rseq() system call" if EXPERT 1841 default y 1842 depends on HAVE_RSEQ 1843 select MEMBARRIER 1844 help 1845 Enable the restartable sequences system call. It provides a 1846 user-space cache for the current CPU number value, which 1847 speeds up getting the current CPU number from user-space, 1848 as well as an ABI to speed up user-space operations on 1849 per-CPU data. 1850 1851 If unsure, say Y. 1852 1853config RSEQ_SLICE_EXTENSION 1854 bool "Enable rseq-based time slice extension mechanism" 1855 depends on RSEQ && HIGH_RES_TIMERS && GENERIC_ENTRY && HAVE_GENERIC_TIF_BITS 1856 help 1857 Allows userspace to request a limited time slice extension when 1858 returning from an interrupt to user space via the RSEQ shared 1859 data ABI. If granted, that allows to complete a critical section, 1860 so that other threads are not stuck on a conflicted resource, 1861 while the task is scheduled out. 1862 1863 If unsure, say N. 1864 1865config RSEQ_STATS 1866 default n 1867 bool "Enable lightweight statistics of restartable sequences" if EXPERT 1868 depends on RSEQ && DEBUG_FS 1869 help 1870 Enable lightweight counters which expose information about the 1871 frequency of RSEQ operations via debugfs. Mostly interesting for 1872 kernel debugging or performance analysis. While lightweight it's 1873 still adding code into the user/kernel mode transitions. 1874 1875 If unsure, say N. 1876 1877config RSEQ_DEBUG_DEFAULT_ENABLE 1878 default n 1879 bool "Enable restartable sequences debug mode by default" if EXPERT 1880 depends on RSEQ 1881 help 1882 This enables the static branch for debug mode of restartable 1883 sequences. 1884 1885 This also can be controlled on the kernel command line via the 1886 command line parameter "rseq_debug=0/1" and through debugfs. 1887 1888 If unsure, say N. 1889 1890config DEBUG_RSEQ 1891 default n 1892 bool "Enable debugging of rseq() system call" if EXPERT 1893 depends on RSEQ && DEBUG_KERNEL && !GENERIC_ENTRY 1894 select RSEQ_DEBUG_DEFAULT_ENABLE 1895 help 1896 Enable extra debugging checks for the rseq system call. 1897 1898 If unsure, say N. 1899 1900config CACHESTAT_SYSCALL 1901 bool "Enable cachestat() system call" if EXPERT 1902 default y 1903 help 1904 Enable the cachestat system call, which queries the page cache 1905 statistics of a file (number of cached pages, dirty pages, 1906 pages marked for writeback, (recently) evicted pages). 1907 1908 If unsure say Y here. 1909 1910config KALLSYMS 1911 bool "Load all symbols for debugging/ksymoops" if EXPERT 1912 default y 1913 help 1914 Say Y here to let the kernel print out symbolic crash information and 1915 symbolic stack backtraces. This increases the size of the kernel 1916 somewhat, as all symbols have to be loaded into the kernel image. 1917 1918config KALLSYMS_SELFTEST 1919 bool "Test the basic functions and performance of kallsyms" 1920 depends on KALLSYMS 1921 default n 1922 help 1923 Test the basic functions and performance of some interfaces, such as 1924 kallsyms_lookup_name. It also calculates the compression rate of the 1925 kallsyms compression algorithm for the current symbol set. 1926 1927 Start self-test automatically after system startup. Suggest executing 1928 "dmesg | grep kallsyms_selftest" to collect test results. "finish" is 1929 displayed in the last line, indicating that the test is complete. 1930 1931config KALLSYMS_ALL 1932 bool "Include all symbols in kallsyms" 1933 depends on DEBUG_KERNEL && KALLSYMS 1934 help 1935 Normally kallsyms only contains the symbols of functions for nicer 1936 OOPS messages and backtraces (i.e., symbols from the text and inittext 1937 sections). This is sufficient for most cases. And only if you want to 1938 enable kernel live patching, or other less common use cases (e.g., 1939 when a debugger is used) all symbols are required (i.e., names of 1940 variables from the data sections, etc). 1941 1942 This option makes sure that all symbols are loaded into the kernel 1943 image (i.e., symbols from all sections) in cost of increased kernel 1944 size (depending on the kernel configuration, it may be 300KiB or 1945 something like this). 1946 1947 Say N unless you really need all symbols, or kernel live patching. 1948 1949# end of the "standard kernel features (expert users)" menu 1950 1951config ARCH_HAS_MEMBARRIER_CALLBACKS 1952 bool 1953 1954config ARCH_HAS_MEMBARRIER_SYNC_CORE 1955 bool 1956 1957config ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 1958 bool 1959 help 1960 Control MSEAL_SYSTEM_MAPPINGS access based on architecture. 1961 1962 A 64-bit kernel is required for the memory sealing feature. 1963 No specific hardware features from the CPU are needed. 1964 1965 To enable this feature, the architecture needs to update their 1966 special mappings calls to include the sealing flag and confirm 1967 that it doesn't unmap/remap system mappings during the life 1968 time of the process. The existence of this flag for an architecture 1969 implies that it does not require the remapping of the system 1970 mappings during process lifetime, so sealing these mappings is safe 1971 from a kernel perspective. 1972 1973 After the architecture enables this, a distribution can set 1974 CONFIG_MSEAL_SYSTEM_MAPPINGS to manage access to the feature. 1975 1976 For complete descriptions of memory sealing, please see 1977 Documentation/userspace-api/mseal.rst 1978 1979config HAVE_PERF_EVENTS 1980 bool 1981 help 1982 See tools/perf/design.txt for details. 1983 1984config GUEST_PERF_EVENTS 1985 bool 1986 depends on HAVE_PERF_EVENTS 1987 1988config PERF_GUEST_MEDIATED_PMU 1989 bool 1990 depends on GUEST_PERF_EVENTS 1991 1992config PERF_USE_VMALLOC 1993 bool 1994 help 1995 See tools/perf/design.txt for details 1996 1997menu "Kernel Performance Events And Counters" 1998 1999config PERF_EVENTS 2000 bool "Kernel performance events and counters" 2001 default y if PROFILING 2002 depends on HAVE_PERF_EVENTS 2003 select IRQ_WORK 2004 help 2005 Enable kernel support for various performance events provided 2006 by software and hardware. 2007 2008 Software events are supported either built-in or via the 2009 use of generic tracepoints. 2010 2011 Most modern CPUs support performance events via performance 2012 counter registers. These registers count the number of certain 2013 types of hw events: such as instructions executed, cachemisses 2014 suffered, or branches mis-predicted - without slowing down the 2015 kernel or applications. These registers can also trigger interrupts 2016 when a threshold number of events have passed - and can thus be 2017 used to profile the code that runs on that CPU. 2018 2019 The Linux Performance Event subsystem provides an abstraction of 2020 these software and hardware event capabilities, available via a 2021 system call and used by the "perf" utility in tools/perf/. It 2022 provides per task and per CPU counters, and it provides event 2023 capabilities on top of those. 2024 2025 Say Y if unsure. 2026 2027config DEBUG_PERF_USE_VMALLOC 2028 default n 2029 bool "Debug: use vmalloc to back perf mmap() buffers" 2030 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC 2031 select PERF_USE_VMALLOC 2032 help 2033 Use vmalloc memory to back perf mmap() buffers. 2034 2035 Mostly useful for debugging the vmalloc code on platforms 2036 that don't require it. 2037 2038 Say N if unsure. 2039 2040endmenu 2041 2042config SYSTEM_DATA_VERIFICATION 2043 def_bool n 2044 select SYSTEM_TRUSTED_KEYRING 2045 select KEYS 2046 select CRYPTO 2047 select CRYPTO_RSA 2048 select ASYMMETRIC_KEY_TYPE 2049 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE 2050 select ASN1 2051 select OID_REGISTRY 2052 select X509_CERTIFICATE_PARSER 2053 select PKCS7_MESSAGE_PARSER 2054 help 2055 Provide PKCS#7 message verification using the contents of the system 2056 trusted keyring to provide public keys. This then can be used for 2057 module verification, kexec image verification and firmware blob 2058 verification. 2059 2060config PROFILING 2061 bool "Profiling support" 2062 help 2063 Say Y here to enable the extended profiling support mechanisms used 2064 by profilers. 2065 2066config RUST 2067 bool "Rust support" 2068 depends on HAVE_RUST 2069 depends on RUST_IS_AVAILABLE 2070 select EXTENDED_MODVERSIONS if MODVERSIONS 2071 depends on !MODVERSIONS || GENDWARFKSYMS 2072 depends on !GCC_PLUGIN_RANDSTRUCT 2073 depends on !RANDSTRUCT 2074 depends on !DEBUG_INFO_BTF || (PAHOLE_HAS_LANG_EXCLUDE && !LTO) 2075 depends on !CFI || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC 2076 select CFI_ICALL_NORMALIZE_INTEGERS if CFI 2077 depends on !KASAN || CC_IS_CLANG 2078 depends on !KASAN_SW_TAGS || RUSTC_VERSION >= 109600 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 2092source "rust/kernel/Kconfig.test" 2093 2094config RUSTC_VERSION_TEXT 2095 string 2096 depends on RUST 2097 default "$(RUSTC_VERSION_TEXT)" 2098 help 2099 See `CC_VERSION_TEXT`. 2100 2101config BINDGEN_VERSION_TEXT 2102 string 2103 depends on RUST 2104 default "$(shell,$(BINDGEN) --version 2>/dev/null)" 2105 2106# 2107# Place an empty function call at each tracepoint site. Can be 2108# dynamically changed for a probe function. 2109# 2110config TRACEPOINTS 2111 bool 2112 select TASKS_TRACE_RCU 2113 2114source "kernel/Kconfig.kexec" 2115 2116source "kernel/liveupdate/Kconfig" 2117 2118endmenu # General setup 2119 2120source "arch/Kconfig" 2121 2122config RT_MUTEXES 2123 bool 2124 default y if PREEMPT_RT 2125 2126config MODULE_SIG_FORMAT 2127 def_bool n 2128 select SYSTEM_DATA_VERIFICATION 2129 2130source "kernel/module/Kconfig" 2131 2132config INIT_ALL_POSSIBLE 2133 bool 2134 help 2135 Back when each arch used to define their own cpu_online_mask and 2136 cpu_possible_mask, some of them chose to initialize cpu_possible_mask 2137 with all 1s, and others with all 0s. When they were centralised, 2138 it was better to provide this option than to break all the archs 2139 and have several arch maintainers pursuing me down dark alleys. 2140 2141source "block/Kconfig" 2142 2143config PREEMPT_NOTIFIERS 2144 bool 2145 2146config PADATA 2147 depends on SMP 2148 bool 2149 2150config ASN1 2151 tristate 2152 help 2153 Build a simple ASN.1 grammar compiler that produces a bytecode output 2154 that can be interpreted by the ASN.1 stream decoder and used to 2155 inform it as to what tags are to be expected in a stream and what 2156 functions to call on what tags. 2157 2158source "kernel/Kconfig.locks" 2159 2160config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 2161 bool 2162 2163config ARCH_HAS_PREPARE_SYNC_CORE_CMD 2164 bool 2165 2166config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 2167 bool 2168 2169# It may be useful for an architecture to override the definitions of the 2170# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> 2171# and the COMPAT_ variants in <linux/compat.h>, in particular to use a 2172# different calling convention for syscalls. They can also override the 2173# macros for not-implemented syscalls in kernel/sys_ni.c and 2174# kernel/time/posix-stubs.c. All these overrides need to be available in 2175# <asm/syscall_wrapper.h>. 2176config ARCH_HAS_SYSCALL_WRAPPER 2177 def_bool n 2178