config/Config-kernel.in

   1 # SPDX-License-Identifier: GPL-2.0-only
   2 #
   3 # Copyright (C) 2006-2014 OpenWrt.org
   4
   5 config KERNEL_BUILD_USER
   6         string "Custom Kernel Build User Name"
   7         default "builder" if BUILDBOT
   8         default ""
   9         help
  10           Sets the Kernel build user string, which for example will be returned
  11           by 'uname -a' on running systems.
  12           If not set, uses system user at build time.
  13
  14 config KERNEL_BUILD_DOMAIN
  15         string "Custom Kernel Build Domain Name"
  16         default "buildhost" if BUILDBOT
  17         default ""
  18         help
  19           Sets the Kernel build domain string, which for example will be
  20           returned by 'uname -a' on running systems.
  21           If not set, uses system hostname at build time.
  22
  23 config KERNEL_PRINTK
  24         bool "Enable support for printk"
  25         default y
  26
  27 config KERNEL_SWAP
  28         bool "Support for paging of anonymous memory (swap)"
  29         default y if !SMALL_FLASH
  30
  31 config KERNEL_PROC_STRIPPED
  32         bool "Strip non-essential /proc functionality to reduce code size"
  33         default y if SMALL_FLASH
  34
  35 config KERNEL_DEBUG_FS
  36         bool "Compile the kernel with debug filesystem enabled"
  37         default y
  38         help
  39           debugfs is a virtual file system that kernel developers use to put
  40           debugging files into. Enable this option to be able to read and
  41           write to these files. Many common debugging facilities, such as
  42           ftrace, require the existence of debugfs.
  43
  44 config KERNEL_MIPS_FP_SUPPORT
  45         bool
  46         default y if TARGET_pistachio
  47
  48 config KERNEL_ARM_PMU
  49         bool
  50         default n
  51         depends on (arm || aarch64)
  52
  53 config KERNEL_X86_VSYSCALL_EMULATION
  54         bool "Enable vsyscall emulation"
  55         default n
  56         depends on x86_64
  57         help
  58           This enables emulation of the legacy vsyscall page.  Disabling
  59           it is roughly equivalent to booting with vsyscall=none, except
  60           that it will also disable the helpful warning if a program
  61           tries to use a vsyscall.  With this option set to N, offending
  62           programs will just segfault, citing addresses of the form
  63           0xffffffffff600?00.
  64
  65           This option is required by many programs built before 2013, and
  66           care should be used even with newer programs if set to N.
  67
  68           Disabling this option saves about 7K of kernel size and
  69           possibly 4K of additional runtime pagetable memory.
  70
  71 config KERNEL_PERF_EVENTS
  72         bool "Compile the kernel with performance events and counters"
  73         default n
  74         select KERNEL_ARM_PMU if (arm || aarch64)
  75
  76 config KERNEL_PROFILING
  77         bool "Compile the kernel with profiling enabled"
  78         default n
  79         select KERNEL_PERF_EVENTS
  80         help
  81           Enable the extended profiling support mechanisms used by profilers such
  82           as OProfile.
  83
  84 config KERNEL_RPI_AXIPERF
  85         bool "Compile the kernel with RaspberryPi AXI Performance monitors"
  86         default y
  87         depends on KERNEL_PERF_EVENTS && TARGET_bcm27xx
  88
  89 config KERNEL_UBSAN
  90         bool "Compile the kernel with undefined behaviour sanity checker"
  91         help
  92           This option enables undefined behaviour sanity checker
  93           Compile-time instrumentation is used to detect various undefined
  94           behaviours in runtime. Various types of checks may be enabled
  95           via boot parameter ubsan_handle
  96           (see: Documentation/dev-tools/ubsan.rst).
  97
  98 config KERNEL_UBSAN_SANITIZE_ALL
  99         bool "Enable instrumentation for the entire kernel"
 100         depends on KERNEL_UBSAN
 101         default y
 102         help
 103           This option activates instrumentation for the entire kernel.
 104           If you don't enable this option, you have to explicitly specify
 105           UBSAN_SANITIZE := y for the files/directories you want to check for UB.
 106           Enabling this option will get kernel image size increased
 107           significantly.
 108
 109 config KERNEL_UBSAN_ALIGNMENT
 110         bool "Enable checking of pointers alignment"
 111         depends on KERNEL_UBSAN
 112         help
 113           This option enables detection of unaligned memory accesses.
 114           Enabling this option on architectures that support unaligned
 115           accesses may produce a lot of false positives.
 116
 117 config KERNEL_UBSAN_BOUNDS
 118         bool "Perform array index bounds checking"
 119         depends on KERNEL_UBSAN
 120         help
 121           This option enables detection of directly indexed out of bounds array
 122           accesses, where the array size is known at compile time. Note that
 123           this does not protect array overflows via bad calls to the
 124           {str,mem}*cpy() family of functions (that is addressed by
 125           FORTIFY_SOURCE).
 126
 127 config KERNEL_UBSAN_NULL
 128         bool "Enable checking of null pointers"
 129         depends on KERNEL_UBSAN
 130         help
 131           This option enables detection of memory accesses via a
 132           null pointer.
 133
 134 config KERNEL_UBSAN_TRAP
 135         bool "On Sanitizer warnings, abort the running kernel code"
 136         depends on KERNEL_UBSAN
 137         help
 138           Building kernels with Sanitizer features enabled tends to grow the
 139           kernel size by around 5%, due to adding all the debugging text on
 140           failure paths. To avoid this, Sanitizer instrumentation can just
 141           issue a trap. This reduces the kernel size overhead but turns all
 142           warnings (including potentially harmless conditions) into full
 143           exceptions that abort the running kernel code (regardless of context,
 144           locks held, etc), which may destabilize the system. For some system
 145           builders this is an acceptable trade-off.
 146
 147 config KERNEL_KASAN
 148         bool "Compile the kernel with KASan: runtime memory debugger"
 149         select KERNEL_SLUB_DEBUG
 150         depends on (x86_64 || aarch64)
 151         help
 152           Enables kernel address sanitizer - runtime memory debugger,
 153           designed to find out-of-bounds accesses and use-after-free bugs.
 154           This is strictly a debugging feature and it requires a gcc version
 155           of 4.9.2 or later. Detection of out of bounds accesses to stack or
 156           global variables requires gcc 5.0 or later.
 157           This feature consumes about 1/8 of available memory and brings about
 158           ~x3 performance slowdown.
 159           For better error detection enable CONFIG_STACKTRACE.
 160           Currently CONFIG_KASAN doesn't work with CONFIG_DEBUG_SLAB
 161           (the resulting kernel does not boot).
 162
 163 config KERNEL_KASAN_EXTRA
 164         bool "KAsan: extra checks"
 165         depends on KERNEL_KASAN && KERNEL_DEBUG_KERNEL
 166         help
 167           This enables further checks in the kernel address sanitizer, for now
 168           it only includes the address-use-after-scope check that can lead
 169           to excessive kernel stack usage, frame size warnings and longer
 170           compile time.
 171           https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 has more
 172
 173 config KERNEL_KASAN_VMALLOC
 174         bool "Back mappings in vmalloc space with real shadow memory"
 175         depends on KERNEL_KASAN
 176         help
 177           By default, the shadow region for vmalloc space is the read-only
 178           zero page. This means that KASAN cannot detect errors involving
 179           vmalloc space.
 180
 181           Enabling this option will hook in to vmap/vmalloc and back those
 182           mappings with real shadow memory allocated on demand. This allows
 183           for KASAN to detect more sorts of errors (and to support vmapped
 184           stacks), but at the cost of higher memory usage.
 185
 186           This option depends on HAVE_ARCH_KASAN_VMALLOC, but we can't
 187           depend on that in here, so it is possible that enabling this
 188           will have no effect.
 189
 190 if KERNEL_KASAN
 191         config KERNEL_KASAN_GENERIC
 192         def_bool y
 193
 194         config KERNEL_KASAN_SW_TAGS
 195         def_bool n
 196 endif
 197
 198 choice
 199         prompt "Instrumentation type"
 200         depends on KERNEL_KASAN
 201         default KERNEL_KASAN_OUTLINE
 202
 203 config KERNEL_KASAN_OUTLINE
 204         bool "Outline instrumentation"
 205         help
 206           Before every memory access compiler insert function call
 207           __asan_load*/__asan_store*. These functions performs check
 208           of shadow memory. This is slower than inline instrumentation,
 209           however it doesn't bloat size of kernel's .text section so
 210           much as inline does.
 211
 212 config KERNEL_KASAN_INLINE
 213         bool "Inline instrumentation"
 214         help
 215           Compiler directly inserts code checking shadow memory before
 216           memory accesses. This is faster than outline (in some workloads
 217           it gives about x2 boost over outline instrumentation), but
 218           make kernel's .text size much bigger.
 219           This requires a gcc version of 5.0 or later.
 220
 221 endchoice
 222
 223 config KERNEL_KCOV
 224         bool "Compile the kernel with code coverage for fuzzing"
 225         select KERNEL_DEBUG_FS
 226         help
 227           KCOV exposes kernel code coverage information in a form suitable
 228           for coverage-guided fuzzing (randomized testing).
 229
 230           If RANDOMIZE_BASE is enabled, PC values will not be stable across
 231           different machines and across reboots. If you need stable PC values,
 232           disable RANDOMIZE_BASE.
 233
 234           For more details, see Documentation/kcov.txt.
 235
 236 config KERNEL_KCOV_ENABLE_COMPARISONS
 237         bool "Enable comparison operands collection by KCOV"
 238         depends on KERNEL_KCOV
 239         help
 240           KCOV also exposes operands of every comparison in the instrumented
 241           code along with operand sizes and PCs of the comparison instructions.
 242           These operands can be used by fuzzing engines to improve the quality
 243           of fuzzing coverage.
 244
 245 config KERNEL_KCOV_INSTRUMENT_ALL
 246         bool "Instrument all code by default"
 247         depends on KERNEL_KCOV
 248         default y if KERNEL_KCOV
 249         help
 250           If you are doing generic system call fuzzing (like e.g. syzkaller),
 251           then you will want to instrument the whole kernel and you should
 252           say y here. If you are doing more targeted fuzzing (like e.g.
 253           filesystem fuzzing with AFL) then you will want to enable coverage
 254           for more specific subsets of files, and should say n here.
 255
 256 config KERNEL_TASKSTATS
 257         bool "Compile the kernel with task resource/io statistics and accounting"
 258         default n
 259         help
 260           Enable the collection and publishing of task/io statistics and
 261           accounting.  Enable this option to enable i/o monitoring in system
 262           monitors.
 263
 264 if KERNEL_TASKSTATS
 265
 266         config KERNEL_TASK_DELAY_ACCT
 267                 def_bool y
 268
 269         config KERNEL_TASK_IO_ACCOUNTING
 270                 def_bool y
 271
 272         config KERNEL_TASK_XACCT
 273                 def_bool y
 274
 275 endif
 276
 277 config KERNEL_KALLSYMS
 278         bool "Compile the kernel with symbol table information"
 279         default y if !SMALL_FLASH
 280         help
 281           This will give you more information in stack traces from kernel oopses.
 282
 283 config KERNEL_FTRACE
 284         bool "Compile the kernel with tracing support"
 285         depends on !TARGET_uml
 286         default n
 287
 288 config KERNEL_FTRACE_SYSCALLS
 289         bool "Trace system calls"
 290         depends on KERNEL_FTRACE
 291         default n
 292
 293 config KERNEL_ENABLE_DEFAULT_TRACERS
 294         bool "Trace process context switches and events"
 295         depends on KERNEL_FTRACE
 296         default n
 297
 298 config KERNEL_FUNCTION_TRACER
 299         bool "Function tracer"
 300         depends on KERNEL_FTRACE
 301         default n
 302
 303 config KERNEL_FUNCTION_GRAPH_TRACER
 304         bool "Function graph tracer"
 305         depends on KERNEL_FUNCTION_TRACER
 306         default n
 307
 308 config KERNEL_DYNAMIC_FTRACE
 309         bool "Enable/disable function tracing dynamically"
 310         depends on KERNEL_FUNCTION_TRACER
 311         default n
 312
 313 config KERNEL_FUNCTION_PROFILER
 314         bool "Function profiler"
 315         depends on KERNEL_FUNCTION_TRACER
 316         default n
 317
 318 config KERNEL_IRQSOFF_TRACER
 319         bool "Interrupts-off Latency Tracer"
 320         depends on KERNEL_FTRACE
 321         help
 322           This option measures the time spent in irqs-off critical
 323           sections, with microsecond accuracy.
 324
 325           The default measurement method is a maximum search, which is
 326           disabled by default and can be runtime (re-)started
 327           via:
 328
 329               echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 330
 331           (Note that kernel size and overhead increase with this option
 332           enabled. This option and the preempt-off timing option can be
 333           used together or separately.)
 334
 335 config KERNEL_PREEMPT_TRACER
 336         bool "Preemption-off Latency Tracer"
 337         depends on KERNEL_FTRACE
 338         help
 339           This option measures the time spent in preemption-off critical
 340           sections, with microsecond accuracy.
 341
 342           The default measurement method is a maximum search, which is
 343           disabled by default and can be runtime (re-)started
 344           via:
 345
 346               echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 347
 348           (Note that kernel size and overhead increase with this option
 349           enabled. This option and the irqs-off timing option can be
 350           used together or separately.)
 351
 352 config KERNEL_HIST_TRIGGERS
 353         bool "Histogram triggers"
 354         depends on KERNEL_FTRACE
 355         help
 356           Hist triggers allow one or more arbitrary trace event fields to be
 357           aggregated into hash tables and dumped to stdout by reading a
 358           debugfs/tracefs file. They're useful for gathering quick and dirty
 359           (though precise) summaries of event activity as an initial guide for
 360           further investigation using more advanced tools.
 361
 362           Inter-event tracing of quantities such as latencies is also
 363           supported using hist triggers under this option.
 364
 365 config KERNEL_DEBUG_KERNEL
 366         bool
 367         default n
 368
 369 config KERNEL_DEBUG_INFO
 370         bool "Compile the kernel with debug information"
 371         default y if !SMALL_FLASH
 372         select KERNEL_DEBUG_KERNEL
 373         help
 374           This will compile your kernel and modules with debug information.
 375
 376 config KERNEL_DEBUG_LL_UART_NONE
 377         bool
 378         default n
 379         depends on arm
 380
 381 config KERNEL_DEBUG_LL
 382         bool
 383         default n
 384         depends on arm
 385         select KERNEL_DEBUG_LL_UART_NONE
 386         help
 387           ARM low level debugging.
 388
 389 config KERNEL_DYNAMIC_DEBUG
 390         bool "Compile the kernel with dynamic printk"
 391         select KERNEL_DEBUG_FS
 392         default n
 393         help
 394           Compiles debug level messages into the kernel, which would not
 395           otherwise be available at runtime. These messages can then be
 396           enabled/disabled based on various levels of scope - per source file,
 397           function, module, format string, and line number. This mechanism
 398           implicitly compiles in all pr_debug() and dev_dbg() calls, which
 399           enlarges the kernel text size by about 2%.
 400
 401 config KERNEL_EARLY_PRINTK
 402         bool "Compile the kernel with early printk"
 403         default y if TARGET_bcm53xx
 404         default n
 405         depends on arm
 406         select KERNEL_DEBUG_KERNEL
 407         select KERNEL_DEBUG_LL if arm
 408         help
 409           Compile the kernel with early printk support.  This is only useful for
 410           debugging purposes to send messages over the serial console in early boot.
 411           Enable this to debug early boot problems.
 412
 413 config KERNEL_KPROBES
 414         bool "Compile the kernel with kprobes support"
 415         default n
 416         select KERNEL_FTRACE
 417         select KERNEL_PERF_EVENTS
 418         help
 419           Compiles the kernel with KPROBES support, which allows you to trap
 420           at almost any kernel address and execute a callback function.
 421           register_kprobe() establishes a probepoint and specifies the
 422           callback. Kprobes is useful for kernel debugging, non-intrusive
 423           instrumentation and testing.
 424           If in doubt, say "N".
 425
 426 config KERNEL_KPROBE_EVENTS
 427         bool
 428         default y if KERNEL_KPROBES
 429
 430 config KERNEL_BPF_KPROBE_OVERRIDE
 431         bool
 432         depends on KERNEL_KPROBES
 433         default n
 434
 435 config KERNEL_AIO
 436         bool "Compile the kernel with asynchronous IO support"
 437         default y if !SMALL_FLASH
 438
 439 config KERNEL_IO_URING
 440         bool "Compile the kernel with io_uring support"
 441         default y if !SMALL_FLASH
 442
 443 config KERNEL_FHANDLE
 444         bool "Compile the kernel with support for fhandle syscalls"
 445         default y if !SMALL_FLASH
 446
 447 config KERNEL_FANOTIFY
 448         bool "Compile the kernel with modern file notification support"
 449         default y if !SMALL_FLASH
 450
 451 config KERNEL_BLK_DEV_BSG
 452         bool "Compile the kernel with SCSI generic v4 support for any block device"
 453         default n
 454
 455 config KERNEL_TRANSPARENT_HUGEPAGE
 456         bool
 457
 458 choice
 459         prompt "Transparent Hugepage Support sysfs defaults"
 460         depends on KERNEL_TRANSPARENT_HUGEPAGE
 461         default KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
 462
 463         config KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
 464                 bool "always"
 465
 466         config KERNEL_TRANSPARENT_HUGEPAGE_MADVISE
 467                 bool "madvise"
 468 endchoice
 469
 470 config KERNEL_HUGETLBFS
 471         bool
 472
 473 config KERNEL_HUGETLB_PAGE
 474         bool "Compile the kernel with HugeTLB support"
 475         select KERNEL_TRANSPARENT_HUGEPAGE
 476         select KERNEL_HUGETLBFS
 477         default n
 478
 479 config KERNEL_MAGIC_SYSRQ
 480         bool "Compile the kernel with SysRq support"
 481         default y
 482
 483 config KERNEL_DEBUG_PINCTRL
 484         bool "Compile the kernel with pinctrl debugging"
 485         select KERNEL_DEBUG_KERNEL
 486
 487 config KERNEL_DEBUG_GPIO
 488         bool "Compile the kernel with gpio debugging"
 489         select KERNEL_DEBUG_KERNEL
 490
 491 config KERNEL_COREDUMP
 492         bool
 493
 494 config KERNEL_ELF_CORE
 495         bool "Enable process core dump support"
 496         select KERNEL_COREDUMP
 497         default y if !SMALL_FLASH
 498
 499 config KERNEL_PROVE_LOCKING
 500         bool "Enable kernel lock checking"
 501         select KERNEL_DEBUG_KERNEL
 502         default n
 503
 504 config KERNEL_SOFTLOCKUP_DETECTOR
 505         bool "Compile the kernel with detect Soft Lockups"
 506         depends on KERNEL_DEBUG_KERNEL
 507         help
 508           Say Y here to enable the kernel to act as a watchdog to detect
 509           soft lockups.
 510
 511           Softlockups are bugs that cause the kernel to loop in kernel
 512           mode for more than 20 seconds, without giving other tasks a
 513           chance to run.  The current stack trace is displayed upon
 514           detection and the system will stay locked up.
 515
 516 config KERNEL_DETECT_HUNG_TASK
 517         bool "Compile the kernel with detect Hung Tasks"
 518         depends on KERNEL_DEBUG_KERNEL
 519         default KERNEL_SOFTLOCKUP_DETECTOR
 520         help
 521           Say Y here to enable the kernel to detect "hung tasks",
 522           which are bugs that cause the task to be stuck in
 523           uninterruptible "D" state indefinitely.
 524
 525           When a hung task is detected, the kernel will print the
 526           current stack trace (which you should report), but the
 527           task will stay in uninterruptible state. If lockdep is
 528           enabled then all held locks will also be reported. This
 529           feature has negligible overhead.
 530
 531 config KERNEL_WQ_WATCHDOG
 532         bool "Compile the kernel with detect Workqueue Stalls"
 533         depends on KERNEL_DEBUG_KERNEL
 534         help
 535           Say Y here to enable stall detection on workqueues.  If a
 536           worker pool doesn't make forward progress on a pending work
 537           item for over a given amount of time, 30s by default, a
 538           warning message is printed along with dump of workqueue
 539           state.  This can be configured through kernel parameter
 540           "workqueue.watchdog_thresh" and its sysfs counterpart.
 541
 542 config KERNEL_DEBUG_ATOMIC_SLEEP
 543         bool "Compile the kernel with sleep inside atomic section checking"
 544         depends on KERNEL_DEBUG_KERNEL
 545         help
 546           If you say Y here, various routines which may sleep will become very
 547           noisy if they are called inside atomic sections: when a spinlock is
 548           held, inside an rcu read side critical section, inside preempt disabled
 549           sections, inside an interrupt, etc...
 550
 551 config KERNEL_DEBUG_VM
 552         bool "Compile the kernel with debug VM"
 553         depends on KERNEL_DEBUG_KERNEL
 554         help
 555           Enable this to turn on extended checks in the virtual-memory system
 556           that may impact performance.
 557
 558           If unsure, say N.
 559
 560 config KERNEL_PRINTK_TIME
 561         bool "Enable printk timestamps"
 562         default y
 563
 564 config KERNEL_SLUB_DEBUG
 565         bool
 566
 567 config KERNEL_SLUB_DEBUG_ON
 568         bool
 569
 570 config KERNEL_SLABINFO
 571         select KERNEL_SLUB_DEBUG
 572         select KERNEL_SLUB_DEBUG_ON
 573         bool "Enable /proc slab debug info"
 574
 575 config KERNEL_PROC_PAGE_MONITOR
 576         bool "Enable /proc page monitoring"
 577
 578 config KERNEL_RELAY
 579         bool
 580
 581 config KERNEL_KEXEC
 582         bool "Enable kexec support"
 583
 584 config KERNEL_PROC_VMCORE
 585         bool
 586
 587 config KERNEL_PROC_KCORE
 588         bool
 589
 590 config KERNEL_CRASH_DUMP
 591         depends on i386 || x86_64 || arm || armeb
 592         select KERNEL_KEXEC
 593         select KERNEL_PROC_VMCORE
 594         select KERNEL_PROC_KCORE
 595         bool "Enable support for kexec crashdump"
 596         default y
 597
 598 config USE_RFKILL
 599         bool "Enable rfkill support"
 600         default RFKILL_SUPPORT
 601
 602 config USE_SPARSE
 603         bool "Enable sparse check during kernel build"
 604         default n
 605
 606 config KERNEL_DEVTMPFS
 607         bool "Compile the kernel with device tmpfs enabled"
 608         default n
 609         help
 610           devtmpfs is a simple, kernel-managed /dev filesystem. The kernel creates
 611           devices nodes for all registered devices to simplify boot, but leaves more
 612           complex tasks to userspace (e.g. udev).
 613
 614 if KERNEL_DEVTMPFS
 615
 616         config KERNEL_DEVTMPFS_MOUNT
 617                 bool "Automatically mount devtmpfs after root filesystem is mounted"
 618                 default n
 619
 620 endif
 621
 622 config KERNEL_KEYS
 623         bool "Enable kernel access key retention support"
 624         default !SMALL_FLASH
 625
 626 config KERNEL_PERSISTENT_KEYRINGS
 627         bool "Enable kernel persistent keyrings"
 628         depends on KERNEL_KEYS
 629         default n
 630
 631 config KERNEL_KEYS_REQUEST_CACHE
 632         bool "Enable temporary caching of the last request_key() result"
 633         depends on KERNEL_KEYS
 634         default n
 635
 636 config KERNEL_BIG_KEYS
 637         bool "Enable large payload keys on kernel keyrings"
 638         depends on KERNEL_KEYS
 639         default n
 640
 641 #
 642 # CGROUP support symbols
 643 #
 644
 645 config KERNEL_CGROUPS
 646         bool "Enable kernel cgroups"
 647         default y if !SMALL_FLASH
 648
 649 if KERNEL_CGROUPS
 650
 651         config KERNEL_CGROUP_DEBUG
 652                 bool "Example debug cgroup subsystem"
 653                 default n
 654                 help
 655                   This option enables a simple cgroup subsystem that
 656                   exports useful debugging information about the cgroups
 657                   framework.
 658
 659         config KERNEL_FREEZER
 660                 bool
 661
 662         config KERNEL_CGROUP_FREEZER
 663                 bool "legacy Freezer cgroup subsystem"
 664                 default n
 665                 select KERNEL_FREEZER
 666                 help
 667                   Provides a way to freeze and unfreeze all tasks in a
 668                   cgroup.
 669                   (legacy cgroup1-only controller, in cgroup2 freezer
 670                   is integrated in the Memory controller)
 671
 672         config KERNEL_CGROUP_DEVICE
 673                 bool "legacy Device controller for cgroups"
 674                 default n
 675                 help
 676                   Provides a cgroup implementing whitelists for devices which
 677                   a process in the cgroup can mknod or open.
 678                   (legacy cgroup1-only controller)
 679
 680         config KERNEL_CGROUP_HUGETLB
 681                 bool "HugeTLB controller"
 682                 default n
 683                 select KERNEL_HUGETLB_PAGE
 684
 685         config KERNEL_CGROUP_PIDS
 686                 bool "PIDs cgroup subsystem"
 687                 default y
 688                 help
 689                   Provides enforcement of process number limits in the scope of a
 690                   cgroup.
 691
 692         config KERNEL_CGROUP_RDMA
 693                 bool "RDMA controller for cgroups"
 694                 default y
 695
 696         config KERNEL_CGROUP_BPF
 697                 bool "Support for eBPF programs attached to cgroups"
 698                 default y
 699
 700         config KERNEL_CPUSETS
 701                 bool "Cpuset support"
 702                 default y
 703                 help
 704                   This option will let you create and manage CPUSETs which
 705                   allow dynamically partitioning a system into sets of CPUs and
 706                   Memory Nodes and assigning tasks to run only within those sets.
 707                   This is primarily useful on large SMP or NUMA systems.
 708
 709         config KERNEL_PROC_PID_CPUSET
 710                 bool "Include legacy /proc/<pid>/cpuset file"
 711                 default n
 712                 depends on KERNEL_CPUSETS
 713
 714         config KERNEL_CGROUP_CPUACCT
 715                 bool "Simple CPU accounting cgroup subsystem"
 716                 default y
 717                 help
 718                   Provides a simple Resource Controller for monitoring the
 719                   total CPU consumed by the tasks in a cgroup.
 720
 721         config KERNEL_RESOURCE_COUNTERS
 722                 bool "Resource counters"
 723                 default y
 724                 help
 725                   This option enables controller independent resource accounting
 726                   infrastructure that works with cgroups.
 727
 728         config KERNEL_MM_OWNER
 729                 bool
 730                 default y if KERNEL_MEMCG
 731
 732         config KERNEL_MEMCG
 733                 bool "Memory Resource Controller for Control Groups"
 734                 default y
 735                 select KERNEL_FREEZER
 736                 depends on KERNEL_RESOURCE_COUNTERS || !LINUX_3_18
 737                 help
 738                   Provides a memory resource controller that manages both anonymous
 739                   memory and page cache. (See Documentation/cgroups/memory.txt)
 740
 741                   Note that setting this option increases fixed memory overhead
 742                   associated with each page of memory in the system. By this,
 743                   20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
 744                   usage tracking struct at boot. Total amount of this is printed out
 745                   at boot.
 746
 747                   Only enable when you're ok with these tradeoffs and really
 748                   sure you need the memory resource controller. Even when you enable
 749                   this, you can set "cgroup_disable=memory" at your boot option to
 750                   disable memory resource controller and you can avoid overheads
 751                   (but lose benefits of memory resource controller).
 752
 753                   This config option also selects MM_OWNER config option, which
 754                   could in turn add some fork/exit overhead.
 755
 756         config KERNEL_MEMCG_SWAP
 757                 bool "Memory Resource Controller Swap Extension"
 758                 default y
 759                 depends on KERNEL_MEMCG
 760                 help
 761                   Add swap management feature to memory resource controller. When you
 762                   enable this, you can limit mem+swap usage per cgroup. In other words,
 763                   when you disable this, memory resource controller has no cares to
 764                   usage of swap...a process can exhaust all of the swap. This extension
 765                   is useful when you want to avoid exhaustion swap but this itself
 766                   adds more overheads and consumes memory for remembering information.
 767                   Especially if you use 32bit system or small memory system, please
 768                   be careful about enabling this. When memory resource controller
 769                   is disabled by boot option, this will be automatically disabled and
 770                   there will be no overhead from this. Even when you set this config=y,
 771                   if boot option "swapaccount=0" is set, swap will not be accounted.
 772                   Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
 773                   size is 4096bytes, 512k per 1Gbytes of swap.
 774
 775         config KERNEL_MEMCG_SWAP_ENABLED
 776                 bool "Memory Resource Controller Swap Extension enabled by default"
 777                 default n
 778                 depends on KERNEL_MEMCG_SWAP
 779                 help
 780                   Memory Resource Controller Swap Extension comes with its price in
 781                   a bigger memory consumption. General purpose distribution kernels
 782                   which want to enable the feature but keep it disabled by default
 783                   and let the user enable it by swapaccount boot command line
 784                   parameter should have this option unselected.
 785
 786                   Those who want to have the feature enabled by default should
 787                   select this option (if, for some reason, they need to disable it,
 788                   then swapaccount=0 does the trick).
 789
 790
 791         config KERNEL_MEMCG_KMEM
 792                 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
 793                 default y
 794                 depends on KERNEL_MEMCG
 795                 help
 796                   The Kernel Memory extension for Memory Resource Controller can limit
 797                   the amount of memory used by kernel objects in the system. Those are
 798                   fundamentally different from the entities handled by the standard
 799                   Memory Controller, which are page-based, and can be swapped. Users of
 800                   the kmem extension can use it to guarantee that no group of processes
 801                   will ever exhaust kernel resources alone.
 802
 803         config KERNEL_CGROUP_PERF
 804                 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
 805                 select KERNEL_PERF_EVENTS
 806                 default n
 807                 help
 808                   This option extends the per-cpu mode to restrict monitoring to
 809                   threads which belong to the cgroup specified and run on the
 810                   designated cpu.
 811
 812         menuconfig KERNEL_CGROUP_SCHED
 813                 bool "Group CPU scheduler"
 814                 default y
 815                 help
 816                   This feature lets CPU scheduler recognize task groups and control CPU
 817                   bandwidth allocation to such task groups. It uses cgroups to group
 818                   tasks.
 819
 820         if KERNEL_CGROUP_SCHED
 821
 822                 config KERNEL_FAIR_GROUP_SCHED
 823                         bool "Group scheduling for SCHED_OTHER"
 824                         default y
 825
 826                 config KERNEL_CFS_BANDWIDTH
 827                         bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
 828                         default y
 829                         depends on KERNEL_FAIR_GROUP_SCHED
 830                         help
 831                           This option allows users to define CPU bandwidth rates (limits) for
 832                           tasks running within the fair group scheduler.  Groups with no limit
 833                           set are considered to be unconstrained and will run with no
 834                           restriction.
 835                           See tip/Documentation/scheduler/sched-bwc.txt for more information.
 836
 837                 config KERNEL_RT_GROUP_SCHED
 838                         bool "Group scheduling for SCHED_RR/FIFO"
 839                         default y
 840                         help
 841                           This feature lets you explicitly allocate real CPU bandwidth
 842                           to task groups. If enabled, it will also make it impossible to
 843                           schedule realtime tasks for non-root users until you allocate
 844                           realtime bandwidth for them.
 845
 846         endif
 847
 848         config KERNEL_BLK_CGROUP
 849                 bool "Block IO controller"
 850                 default y
 851                 help
 852                   Generic block IO controller cgroup interface. This is the common
 853                   cgroup interface which should be used by various IO controlling
 854                   policies.
 855
 856                   Currently, CFQ IO scheduler uses it to recognize task groups and
 857                   control disk bandwidth allocation (proportional time slice allocation)
 858                   to such task groups. It is also used by bio throttling logic in
 859                   block layer to implement upper limit in IO rates on a device.
 860
 861                   This option only enables generic Block IO controller infrastructure.
 862                   One needs to also enable actual IO controlling logic/policy. For
 863                   enabling proportional weight division of disk bandwidth in CFQ, set
 864                   CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
 865                   CONFIG_BLK_DEV_THROTTLING=y.
 866
 867         if KERNEL_BLK_CGROUP
 868
 869                 config KERNEL_CFQ_GROUP_IOSCHED
 870                         bool "Proportional weight of disk bandwidth in CFQ"
 871
 872                 config KERNEL_BLK_DEV_THROTTLING
 873                         bool "Enable throttling policy"
 874                         default y
 875
 876                 config KERNEL_BLK_DEV_THROTTLING_LOW
 877                         bool "Block throttling .low limit interface support (EXPERIMENTAL)"
 878                         depends on KERNEL_BLK_DEV_THROTTLING
 879         endif
 880
 881         config KERNEL_DEBUG_BLK_CGROUP
 882                 bool "Enable Block IO controller debugging"
 883                 default n
 884                 depends on KERNEL_BLK_CGROUP
 885                 help
 886                   Enable some debugging help. Currently it exports additional stat
 887                   files in a cgroup which can be useful for debugging.
 888
 889         config KERNEL_NET_CLS_CGROUP
 890                 bool "legacy Control Group Classifier"
 891                 default n
 892
 893         config KERNEL_CGROUP_NET_CLASSID
 894                 bool "legacy Network classid cgroup"
 895                 default n
 896
 897         config KERNEL_CGROUP_NET_PRIO
 898                 bool "legacy Network priority cgroup"
 899                 default n
 900
 901 endif
 902
 903 #
 904 # Namespace support symbols
 905 #
 906
 907 config KERNEL_NAMESPACES
 908         bool "Enable kernel namespaces"
 909         default y if !SMALL_FLASH
 910
 911 if KERNEL_NAMESPACES
 912
 913         config KERNEL_UTS_NS
 914                 bool "UTS namespace"
 915                 default y
 916                 help
 917                   In this namespace, tasks see different info provided
 918                   with the uname() system call.
 919
 920         config KERNEL_IPC_NS
 921                 bool "IPC namespace"
 922                 default y
 923                 help
 924                   In this namespace, tasks work with IPC ids which correspond to
 925                   different IPC objects in different namespaces.
 926
 927         config KERNEL_USER_NS
 928                 bool "User namespace (EXPERIMENTAL)"
 929                 default y
 930                 help
 931                   This allows containers, i.e. vservers, to use user namespaces
 932                   to provide different user info for different servers.
 933
 934         config KERNEL_PID_NS
 935                 bool "PID Namespaces"
 936                 default y
 937                 help
 938                   Support process id namespaces. This allows having multiple
 939                   processes with the same pid as long as they are in different
 940                   pid namespaces. This is a building block of containers.
 941
 942         config KERNEL_NET_NS
 943                 bool "Network namespace"
 944                 default y
 945                 help
 946                   Allow user space to create what appear to be multiple instances
 947                   of the network stack.
 948
 949 endif
 950
 951 config KERNEL_DEVPTS_MULTIPLE_INSTANCES
 952         bool "Support multiple instances of devpts"
 953         default y if !SMALL_FLASH
 954         help
 955           Enable support for multiple instances of devpts filesystem.
 956           If you want to have isolated PTY namespaces (eg: in containers),
 957           say Y here. Otherwise, say N. If enabled, each mount of devpts
 958           filesystem with the '-o newinstance' option will create an
 959           independent PTY namespace.
 960
 961 config KERNEL_POSIX_MQUEUE
 962         bool "POSIX Message Queues"
 963         default y if !SMALL_FLASH
 964         help
 965           POSIX variant of message queues is a part of IPC. In POSIX message
 966           queues every message has a priority which decides about succession
 967           of receiving it by a process. If you want to compile and run
 968           programs written e.g. for Solaris with use of its POSIX message
 969           queues (functions mq_*) say Y here.
 970
 971           POSIX message queues are visible as a filesystem called 'mqueue'
 972           and can be mounted somewhere if you want to do filesystem
 973           operations on message queues.
 974
 975
 976 config KERNEL_SECCOMP_FILTER
 977         bool
 978         default y if !SMALL_FLASH
 979
 980 config KERNEL_SECCOMP
 981         bool "Enable seccomp support"
 982                 depends on !(TARGET_uml)
 983                 select KERNEL_SECCOMP_FILTER
 984                 default y if !SMALL_FLASH
 985                 help
 986                   Build kernel with support for seccomp.
 987
 988 #
 989 # IPv4 configuration
 990 #
 991
 992 config KERNEL_IP_MROUTE
 993         bool "Enable IPv4 multicast routing"
 994         default y
 995         help
 996           Multicast routing requires a multicast routing daemon in
 997           addition to kernel support.
 998
 999 if KERNEL_IP_MROUTE
1000
1001         config KERNEL_IP_MROUTE_MULTIPLE_TABLES
1002                 def_bool y
1003
1004         config KERNEL_IP_PIMSM_V1
1005                 def_bool y
1006
1007         config KERNEL_IP_PIMSM_V2
1008                 def_bool y
1009
1010 endif
1011
1012 #
1013 # IPv6 configuration
1014 #
1015
1016 config KERNEL_IPV6
1017         def_bool IPV6
1018
1019 if KERNEL_IPV6
1020
1021         config KERNEL_IPV6_MULTIPLE_TABLES
1022                 def_bool y
1023
1024         config KERNEL_IPV6_SUBTREES
1025                 def_bool y
1026
1027         config KERNEL_IPV6_MROUTE
1028                 bool "Enable IPv6 multicast routing"
1029                 default y
1030                 help
1031                   Multicast routing requires a multicast routing daemon in
1032                   addition to kernel support.
1033
1034         if KERNEL_IPV6_MROUTE
1035
1036                 config KERNEL_IPV6_MROUTE_MULTIPLE_TABLES
1037                         def_bool y
1038
1039                 config KERNEL_IPV6_PIMSM_V2
1040                         def_bool y
1041
1042         endif
1043
1044         config KERNEL_IPV6_SEG6_LWTUNNEL
1045                 bool "Enable support for lightweight tunnels"
1046                 default y if !SMALL_FLASH
1047                 help
1048                   Using lwtunnel (needed for IPv6 segment routing) requires ip-full package.
1049
1050         config KERNEL_LWTUNNEL_BPF
1051                 def_bool n
1052
1053 endif
1054
1055 #
1056 # Miscellaneous network configuration
1057 #
1058
1059 config KERNEL_NET_L3_MASTER_DEV
1060         bool "L3 Master device support"
1061         help
1062           This module provides glue between core networking code and device
1063           drivers to support L3 master devices like VRF.
1064
1065 #
1066 # NFS related symbols
1067 #
1068 config KERNEL_IP_PNP
1069         bool "Compile the kernel with rootfs on NFS"
1070         help
1071            If you want to make your kernel boot off a NFS server as root
1072            filesystem, select Y here.
1073
1074 if KERNEL_IP_PNP
1075
1076         config KERNEL_IP_PNP_DHCP
1077                 def_bool y
1078
1079         config KERNEL_IP_PNP_BOOTP
1080                 def_bool n
1081
1082         config KERNEL_IP_PNP_RARP
1083                 def_bool n
1084
1085         config KERNEL_NFS_FS
1086                 def_bool y
1087
1088         config KERNEL_NFS_V2
1089                 def_bool y
1090
1091         config KERNEL_NFS_V3
1092                 def_bool y
1093
1094         config KERNEL_ROOT_NFS
1095                 def_bool y
1096
1097 endif
1098
1099 menu "Filesystem ACL and attr support options"
1100         config USE_FS_ACL_ATTR
1101                 bool "Use filesystem ACL and attr support by default"
1102                 default n
1103                 help
1104                   Make using ACLs (e.g. POSIX ACL, NFSv4 ACL) the default
1105                   for kernel and packages, except tmpfs, flash filesystems,
1106                   and old NFS.  Also enable userspace extended attribute support
1107                   by default.  (OpenWrt already has an expection it will be
1108                   present in the kernel).
1109
1110         config KERNEL_FS_POSIX_ACL
1111                 bool "Enable POSIX ACL support"
1112                 default y if USE_FS_ACL_ATTR
1113
1114         config KERNEL_BTRFS_FS_POSIX_ACL
1115                 bool "Enable POSIX ACL for BtrFS Filesystems"
1116                 select KERNEL_FS_POSIX_ACL
1117                 default y if USE_FS_ACL_ATTR
1118
1119         config KERNEL_EXT4_FS_POSIX_ACL
1120                 bool "Enable POSIX ACL for Ext4 Filesystems"
1121                 select KERNEL_FS_POSIX_ACL
1122                 default y if USE_FS_ACL_ATTR
1123
1124         config KERNEL_F2FS_FS_POSIX_ACL
1125                 bool "Enable POSIX ACL for F2FS Filesystems"
1126                 select KERNEL_FS_POSIX_ACL
1127                 default n
1128
1129         config KERNEL_JFFS2_FS_POSIX_ACL
1130                 bool "Enable POSIX ACL for JFFS2 Filesystems"
1131                 select KERNEL_FS_POSIX_ACL
1132                 default n
1133
1134         config KERNEL_TMPFS_POSIX_ACL
1135                 bool "Enable POSIX ACL for TMPFS Filesystems"
1136                 select KERNEL_FS_POSIX_ACL
1137                 default n
1138
1139         config KERNEL_CIFS_ACL
1140                 bool "Enable CIFS ACLs"
1141                 select KERNEL_FS_POSIX_ACL
1142                 default y if USE_FS_ACL_ATTR
1143
1144         config KERNEL_HFS_FS_POSIX_ACL
1145                 bool "Enable POSIX ACL for HFS Filesystems"
1146                 select KERNEL_FS_POSIX_ACL
1147                 default y if USE_FS_ACL_ATTR
1148
1149         config KERNEL_HFSPLUS_FS_POSIX_ACL
1150                 bool "Enable POSIX ACL for HFS+ Filesystems"
1151                 select KERNEL_FS_POSIX_ACL
1152                 default y if USE_FS_ACL_ATTR
1153
1154         config KERNEL_NFS_ACL_SUPPORT
1155                 bool "Enable ACLs for NFS"
1156                 default y if USE_FS_ACL_ATTR
1157
1158         config KERNEL_NFS_V3_ACL_SUPPORT
1159                 bool "Enable ACLs for NFSv3"
1160                 default n
1161
1162         config KERNEL_NFSD_V2_ACL_SUPPORT
1163                 bool "Enable ACLs for NFSDv2"
1164                 default n
1165
1166         config KERNEL_NFSD_V3_ACL_SUPPORT
1167                 bool "Enable ACLs for NFSDv3"
1168                 default n
1169
1170         config KERNEL_REISER_FS_POSIX_ACL
1171                 bool "Enable POSIX ACLs for ReiserFS"
1172                 select KERNEL_FS_POSIX_ACL
1173                 default y if USE_FS_ACL_ATTR
1174
1175         config KERNEL_XFS_POSIX_ACL
1176                 bool "Enable POSIX ACLs for XFS"
1177                 select KERNEL_FS_POSIX_ACL
1178                 default y if USE_FS_ACL_ATTR
1179
1180         config KERNEL_JFS_POSIX_ACL
1181                 bool "Enable POSIX ACLs for JFS"
1182                 select KERNEL_FS_POSIX_ACL
1183                 default y if USE_FS_ACL_ATTR
1184
1185 endmenu
1186
1187 config KERNEL_DEVMEM
1188         bool "/dev/mem virtual device support"
1189         help
1190           Say Y here if you want to support the /dev/mem device.
1191           The /dev/mem device is used to access areas of physical
1192           memory.
1193
1194 config KERNEL_DEVKMEM
1195         bool "/dev/kmem virtual device support"
1196         help
1197           Say Y here if you want to support the /dev/kmem device. The
1198           /dev/kmem device is rarely used, but can be used for certain
1199           kind of kernel debugging operations.
1200
1201 config KERNEL_SQUASHFS_FRAGMENT_CACHE_SIZE
1202         int "Number of squashfs fragments cached"
1203         default 2 if (SMALL_FLASH && !LOW_MEMORY_FOOTPRINT)
1204         default 3
1205
1206 config KERNEL_SQUASHFS_XATTR
1207         bool "Squashfs XATTR support"
1208
1209 #
1210 # compile optimization setting
1211 #
1212 choice
1213         prompt "Compiler optimization level"
1214         default KERNEL_CC_OPTIMIZE_FOR_SIZE if SMALL_FLASH
1215
1216 config KERNEL_CC_OPTIMIZE_FOR_PERFORMANCE
1217         bool "Optimize for performance"
1218         help
1219           This is the default optimization level for the kernel, building
1220           with the "-O2" compiler flag for best performance and most
1221           helpful compile-time warnings.
1222
1223 config KERNEL_CC_OPTIMIZE_FOR_SIZE
1224         bool "Optimize for size"
1225         help
1226           Enabling this option will pass "-Os" instead of "-O2" to
1227           your compiler resulting in a smaller kernel.
1228
1229 endchoice
1230
1231 config KERNEL_AUDIT
1232         bool "Auditing support"
1233
1234 config KERNEL_SECURITY
1235         bool "Enable different security models"
1236
1237 config KERNEL_SECURITY_NETWORK
1238         bool "Socket and Networking Security Hooks"
1239         select KERNEL_SECURITY
1240
1241 config KERNEL_SECURITY_SELINUX
1242         bool "NSA SELinux Support"
1243         select KERNEL_SECURITY_NETWORK
1244         select KERNEL_AUDIT
1245
1246 config KERNEL_SECURITY_SELINUX_BOOTPARAM
1247         bool "NSA SELinux boot parameter"
1248         depends on KERNEL_SECURITY_SELINUX
1249         default y
1250
1251 config KERNEL_SECURITY_SELINUX_DISABLE
1252         bool "NSA SELinux runtime disable"
1253         depends on KERNEL_SECURITY_SELINUX
1254
1255 config KERNEL_SECURITY_SELINUX_DEVELOP
1256         bool "NSA SELinux Development Support"
1257         depends on KERNEL_SECURITY_SELINUX
1258         default y
1259
1260 config KERNEL_SECURITY_SELINUX_SIDTAB_HASH_BITS
1261         int
1262         depends on KERNEL_SECURITY_SELINUX
1263         default 9
1264
1265 config KERNEL_SECURITY_SELINUX_SID2STR_CACHE_SIZE
1266         int
1267         depends on KERNEL_SECURITY_SELINUX
1268         default 256
1269
1270 config KERNEL_LSM
1271         string
1272         default "lockdown,yama,loadpin,safesetid,integrity,selinux"
1273         depends on KERNEL_SECURITY_SELINUX
1274
1275 config KERNEL_EXT4_FS_SECURITY
1276         bool "Ext4 Security Labels"
1277
1278 config KERNEL_F2FS_FS_SECURITY
1279         bool "F2FS Security Labels"
1280
1281 config KERNEL_UBIFS_FS_SECURITY
1282         bool "UBIFS Security Labels"
1283
1284 config KERNEL_JFFS2_FS_SECURITY
1285         bool "JFFS2 Security Labels"