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_INFO_REDUCED
 377         bool "Reduce debugging information"
 378         default y
 379         depends on KERNEL_DEBUG_INFO
 380         help
 381           If you say Y here gcc is instructed to generate less debugging
 382           information for structure types. This means that tools that
 383           need full debugging information (like kgdb or systemtap) won't
 384           be happy. But if you merely need debugging information to
 385           resolve line numbers there is no loss. Advantage is that
 386           build directory object sizes shrink dramatically over a full
 387           DEBUG_INFO build and compile times are reduced too.
 388           Only works with newer gcc versions.
 389
 390 config KERNEL_DEBUG_LL_UART_NONE
 391         bool
 392         default n
 393         depends on arm
 394
 395 config KERNEL_DEBUG_LL
 396         bool
 397         default n
 398         depends on arm
 399         select KERNEL_DEBUG_LL_UART_NONE
 400         help
 401           ARM low level debugging.
 402
 403 config KERNEL_DYNAMIC_DEBUG
 404         bool "Compile the kernel with dynamic printk"
 405         select KERNEL_DEBUG_FS
 406         default n
 407         help
 408           Compiles debug level messages into the kernel, which would not
 409           otherwise be available at runtime. These messages can then be
 410           enabled/disabled based on various levels of scope - per source file,
 411           function, module, format string, and line number. This mechanism
 412           implicitly compiles in all pr_debug() and dev_dbg() calls, which
 413           enlarges the kernel text size by about 2%.
 414
 415 config KERNEL_EARLY_PRINTK
 416         bool "Compile the kernel with early printk"
 417         default y if TARGET_bcm53xx
 418         default n
 419         depends on arm
 420         select KERNEL_DEBUG_KERNEL
 421         select KERNEL_DEBUG_LL if arm
 422         help
 423           Compile the kernel with early printk support.  This is only useful for
 424           debugging purposes to send messages over the serial console in early boot.
 425           Enable this to debug early boot problems.
 426
 427 config KERNEL_KPROBES
 428         bool "Compile the kernel with kprobes support"
 429         default n
 430         select KERNEL_FTRACE
 431         select KERNEL_PERF_EVENTS
 432         help
 433           Compiles the kernel with KPROBES support, which allows you to trap
 434           at almost any kernel address and execute a callback function.
 435           register_kprobe() establishes a probepoint and specifies the
 436           callback. Kprobes is useful for kernel debugging, non-intrusive
 437           instrumentation and testing.
 438           If in doubt, say "N".
 439
 440 config KERNEL_KPROBE_EVENTS
 441         bool
 442         default y if KERNEL_KPROBES
 443
 444 config KERNEL_BPF_KPROBE_OVERRIDE
 445         bool
 446         depends on KERNEL_KPROBES
 447         default n
 448
 449 config KERNEL_AIO
 450         bool "Compile the kernel with asynchronous IO support"
 451         default y if !SMALL_FLASH
 452
 453 config KERNEL_IO_URING
 454         bool "Compile the kernel with io_uring support"
 455         default y if !SMALL_FLASH
 456
 457 config KERNEL_FHANDLE
 458         bool "Compile the kernel with support for fhandle syscalls"
 459         default y if !SMALL_FLASH
 460
 461 config KERNEL_FANOTIFY
 462         bool "Compile the kernel with modern file notification support"
 463         default y if !SMALL_FLASH
 464
 465 config KERNEL_BLK_DEV_BSG
 466         bool "Compile the kernel with SCSI generic v4 support for any block device"
 467         default n
 468
 469 config KERNEL_TRANSPARENT_HUGEPAGE
 470         bool
 471
 472 choice
 473         prompt "Transparent Hugepage Support sysfs defaults"
 474         depends on KERNEL_TRANSPARENT_HUGEPAGE
 475         default KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
 476
 477         config KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
 478                 bool "always"
 479
 480         config KERNEL_TRANSPARENT_HUGEPAGE_MADVISE
 481                 bool "madvise"
 482 endchoice
 483
 484 config KERNEL_HUGETLBFS
 485         bool
 486
 487 config KERNEL_HUGETLB_PAGE
 488         bool "Compile the kernel with HugeTLB support"
 489         select KERNEL_TRANSPARENT_HUGEPAGE
 490         select KERNEL_HUGETLBFS
 491         default n
 492
 493 config KERNEL_MAGIC_SYSRQ
 494         bool "Compile the kernel with SysRq support"
 495         default y
 496
 497 config KERNEL_DEBUG_PINCTRL
 498         bool "Compile the kernel with pinctrl debugging"
 499         select KERNEL_DEBUG_KERNEL
 500
 501 config KERNEL_DEBUG_GPIO
 502         bool "Compile the kernel with gpio debugging"
 503         select KERNEL_DEBUG_KERNEL
 504
 505 config KERNEL_COREDUMP
 506         bool
 507
 508 config KERNEL_ELF_CORE
 509         bool "Enable process core dump support"
 510         select KERNEL_COREDUMP
 511         default y if !SMALL_FLASH
 512
 513 config KERNEL_PROVE_LOCKING
 514         bool "Enable kernel lock checking"
 515         select KERNEL_DEBUG_KERNEL
 516         default n
 517
 518 config KERNEL_SOFTLOCKUP_DETECTOR
 519         bool "Compile the kernel with detect Soft Lockups"
 520         depends on KERNEL_DEBUG_KERNEL
 521         help
 522           Say Y here to enable the kernel to act as a watchdog to detect
 523           soft lockups.
 524
 525           Softlockups are bugs that cause the kernel to loop in kernel
 526           mode for more than 20 seconds, without giving other tasks a
 527           chance to run.  The current stack trace is displayed upon
 528           detection and the system will stay locked up.
 529
 530 config KERNEL_DETECT_HUNG_TASK
 531         bool "Compile the kernel with detect Hung Tasks"
 532         depends on KERNEL_DEBUG_KERNEL
 533         default KERNEL_SOFTLOCKUP_DETECTOR
 534         help
 535           Say Y here to enable the kernel to detect "hung tasks",
 536           which are bugs that cause the task to be stuck in
 537           uninterruptible "D" state indefinitely.
 538
 539           When a hung task is detected, the kernel will print the
 540           current stack trace (which you should report), but the
 541           task will stay in uninterruptible state. If lockdep is
 542           enabled then all held locks will also be reported. This
 543           feature has negligible overhead.
 544
 545 config KERNEL_WQ_WATCHDOG
 546         bool "Compile the kernel with detect Workqueue Stalls"
 547         depends on KERNEL_DEBUG_KERNEL
 548         help
 549           Say Y here to enable stall detection on workqueues.  If a
 550           worker pool doesn't make forward progress on a pending work
 551           item for over a given amount of time, 30s by default, a
 552           warning message is printed along with dump of workqueue
 553           state.  This can be configured through kernel parameter
 554           "workqueue.watchdog_thresh" and its sysfs counterpart.
 555
 556 config KERNEL_DEBUG_ATOMIC_SLEEP
 557         bool "Compile the kernel with sleep inside atomic section checking"
 558         depends on KERNEL_DEBUG_KERNEL
 559         help
 560           If you say Y here, various routines which may sleep will become very
 561           noisy if they are called inside atomic sections: when a spinlock is
 562           held, inside an rcu read side critical section, inside preempt disabled
 563           sections, inside an interrupt, etc...
 564
 565 config KERNEL_DEBUG_VM
 566         bool "Compile the kernel with debug VM"
 567         depends on KERNEL_DEBUG_KERNEL
 568         help
 569           Enable this to turn on extended checks in the virtual-memory system
 570           that may impact performance.
 571
 572           If unsure, say N.
 573
 574 config KERNEL_PRINTK_TIME
 575         bool "Enable printk timestamps"
 576         default y
 577
 578 config KERNEL_SLUB_DEBUG
 579         bool
 580
 581 config KERNEL_SLUB_DEBUG_ON
 582         bool
 583
 584 config KERNEL_SLABINFO
 585         select KERNEL_SLUB_DEBUG
 586         select KERNEL_SLUB_DEBUG_ON
 587         bool "Enable /proc slab debug info"
 588
 589 config KERNEL_PROC_PAGE_MONITOR
 590         bool "Enable /proc page monitoring"
 591
 592 config KERNEL_RELAY
 593         bool
 594
 595 config KERNEL_KEXEC
 596         bool "Enable kexec support"
 597
 598 config KERNEL_PROC_VMCORE
 599         bool
 600
 601 config KERNEL_PROC_KCORE
 602         bool
 603
 604 config KERNEL_CRASH_DUMP
 605         depends on i386 || x86_64 || arm || armeb
 606         select KERNEL_KEXEC
 607         select KERNEL_PROC_VMCORE
 608         select KERNEL_PROC_KCORE
 609         bool "Enable support for kexec crashdump"
 610         default y
 611
 612 config USE_RFKILL
 613         bool "Enable rfkill support"
 614         default RFKILL_SUPPORT
 615
 616 config USE_SPARSE
 617         bool "Enable sparse check during kernel build"
 618         default n
 619
 620 config KERNEL_DEVTMPFS
 621         bool "Compile the kernel with device tmpfs enabled"
 622         default n
 623         help
 624           devtmpfs is a simple, kernel-managed /dev filesystem. The kernel creates
 625           devices nodes for all registered devices to simplify boot, but leaves more
 626           complex tasks to userspace (e.g. udev).
 627
 628 if KERNEL_DEVTMPFS
 629
 630         config KERNEL_DEVTMPFS_MOUNT
 631                 bool "Automatically mount devtmpfs after root filesystem is mounted"
 632                 default n
 633
 634 endif
 635
 636 config KERNEL_KEYS
 637         bool "Enable kernel access key retention support"
 638         default !SMALL_FLASH
 639
 640 config KERNEL_PERSISTENT_KEYRINGS
 641         bool "Enable kernel persistent keyrings"
 642         depends on KERNEL_KEYS
 643         default n
 644
 645 config KERNEL_KEYS_REQUEST_CACHE
 646         bool "Enable temporary caching of the last request_key() result"
 647         depends on KERNEL_KEYS
 648         default n
 649
 650 config KERNEL_BIG_KEYS
 651         bool "Enable large payload keys on kernel keyrings"
 652         depends on KERNEL_KEYS
 653         default n
 654
 655 #
 656 # CGROUP support symbols
 657 #
 658
 659 config KERNEL_CGROUPS
 660         bool "Enable kernel cgroups"
 661         default y if !SMALL_FLASH
 662
 663 if KERNEL_CGROUPS
 664
 665         config KERNEL_CGROUP_DEBUG
 666                 bool "Example debug cgroup subsystem"
 667                 default n
 668                 help
 669                   This option enables a simple cgroup subsystem that
 670                   exports useful debugging information about the cgroups
 671                   framework.
 672
 673         config KERNEL_FREEZER
 674                 bool
 675
 676         config KERNEL_CGROUP_FREEZER
 677                 bool "legacy Freezer cgroup subsystem"
 678                 default n
 679                 select KERNEL_FREEZER
 680                 help
 681                   Provides a way to freeze and unfreeze all tasks in a
 682                   cgroup.
 683                   (legacy cgroup1-only controller, in cgroup2 freezer
 684                   is integrated in the Memory controller)
 685
 686         config KERNEL_CGROUP_DEVICE
 687                 bool "legacy Device controller for cgroups"
 688                 default n
 689                 help
 690                   Provides a cgroup implementing whitelists for devices which
 691                   a process in the cgroup can mknod or open.
 692                   (legacy cgroup1-only controller)
 693
 694         config KERNEL_CGROUP_HUGETLB
 695                 bool "HugeTLB controller"
 696                 default n
 697                 select KERNEL_HUGETLB_PAGE
 698
 699         config KERNEL_CGROUP_PIDS
 700                 bool "PIDs cgroup subsystem"
 701                 default y
 702                 help
 703                   Provides enforcement of process number limits in the scope of a
 704                   cgroup.
 705
 706         config KERNEL_CGROUP_RDMA
 707                 bool "RDMA controller for cgroups"
 708                 default y
 709
 710         config KERNEL_CGROUP_BPF
 711                 bool "Support for eBPF programs attached to cgroups"
 712                 default y
 713
 714         config KERNEL_CPUSETS
 715                 bool "Cpuset support"
 716                 default y
 717                 help
 718                   This option will let you create and manage CPUSETs which
 719                   allow dynamically partitioning a system into sets of CPUs and
 720                   Memory Nodes and assigning tasks to run only within those sets.
 721                   This is primarily useful on large SMP or NUMA systems.
 722
 723         config KERNEL_PROC_PID_CPUSET
 724                 bool "Include legacy /proc/<pid>/cpuset file"
 725                 default n
 726                 depends on KERNEL_CPUSETS
 727
 728         config KERNEL_CGROUP_CPUACCT
 729                 bool "Simple CPU accounting cgroup subsystem"
 730                 default y
 731                 help
 732                   Provides a simple Resource Controller for monitoring the
 733                   total CPU consumed by the tasks in a cgroup.
 734
 735         config KERNEL_RESOURCE_COUNTERS
 736                 bool "Resource counters"
 737                 default y
 738                 help
 739                   This option enables controller independent resource accounting
 740                   infrastructure that works with cgroups.
 741
 742         config KERNEL_MM_OWNER
 743                 bool
 744                 default y if KERNEL_MEMCG
 745
 746         config KERNEL_MEMCG
 747                 bool "Memory Resource Controller for Control Groups"
 748                 default y
 749                 select KERNEL_FREEZER
 750                 depends on KERNEL_RESOURCE_COUNTERS || !LINUX_3_18
 751                 help
 752                   Provides a memory resource controller that manages both anonymous
 753                   memory and page cache. (See Documentation/cgroups/memory.txt)
 754
 755                   Note that setting this option increases fixed memory overhead
 756                   associated with each page of memory in the system. By this,
 757                   20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
 758                   usage tracking struct at boot. Total amount of this is printed out
 759                   at boot.
 760
 761                   Only enable when you're ok with these tradeoffs and really
 762                   sure you need the memory resource controller. Even when you enable
 763                   this, you can set "cgroup_disable=memory" at your boot option to
 764                   disable memory resource controller and you can avoid overheads
 765                   (but lose benefits of memory resource controller).
 766
 767                   This config option also selects MM_OWNER config option, which
 768                   could in turn add some fork/exit overhead.
 769
 770         config KERNEL_MEMCG_SWAP
 771                 bool "Memory Resource Controller Swap Extension"
 772                 default y
 773                 depends on KERNEL_MEMCG
 774                 help
 775                   Add swap management feature to memory resource controller. When you
 776                   enable this, you can limit mem+swap usage per cgroup. In other words,
 777                   when you disable this, memory resource controller has no cares to
 778                   usage of swap...a process can exhaust all of the swap. This extension
 779                   is useful when you want to avoid exhaustion swap but this itself
 780                   adds more overheads and consumes memory for remembering information.
 781                   Especially if you use 32bit system or small memory system, please
 782                   be careful about enabling this. When memory resource controller
 783                   is disabled by boot option, this will be automatically disabled and
 784                   there will be no overhead from this. Even when you set this config=y,
 785                   if boot option "swapaccount=0" is set, swap will not be accounted.
 786                   Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
 787                   size is 4096bytes, 512k per 1Gbytes of swap.
 788
 789         config KERNEL_MEMCG_SWAP_ENABLED
 790                 bool "Memory Resource Controller Swap Extension enabled by default"
 791                 default n
 792                 depends on KERNEL_MEMCG_SWAP
 793                 help
 794                   Memory Resource Controller Swap Extension comes with its price in
 795                   a bigger memory consumption. General purpose distribution kernels
 796                   which want to enable the feature but keep it disabled by default
 797                   and let the user enable it by swapaccount boot command line
 798                   parameter should have this option unselected.
 799
 800                   Those who want to have the feature enabled by default should
 801                   select this option (if, for some reason, they need to disable it,
 802                   then swapaccount=0 does the trick).
 803
 804
 805         config KERNEL_MEMCG_KMEM
 806                 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
 807                 default y
 808                 depends on KERNEL_MEMCG
 809                 help
 810                   The Kernel Memory extension for Memory Resource Controller can limit
 811                   the amount of memory used by kernel objects in the system. Those are
 812                   fundamentally different from the entities handled by the standard
 813                   Memory Controller, which are page-based, and can be swapped. Users of
 814                   the kmem extension can use it to guarantee that no group of processes
 815                   will ever exhaust kernel resources alone.
 816
 817         config KERNEL_CGROUP_PERF
 818                 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
 819                 select KERNEL_PERF_EVENTS
 820                 default n
 821                 help
 822                   This option extends the per-cpu mode to restrict monitoring to
 823                   threads which belong to the cgroup specified and run on the
 824                   designated cpu.
 825
 826         menuconfig KERNEL_CGROUP_SCHED
 827                 bool "Group CPU scheduler"
 828                 default y
 829                 help
 830                   This feature lets CPU scheduler recognize task groups and control CPU
 831                   bandwidth allocation to such task groups. It uses cgroups to group
 832                   tasks.
 833
 834         if KERNEL_CGROUP_SCHED
 835
 836                 config KERNEL_FAIR_GROUP_SCHED
 837                         bool "Group scheduling for SCHED_OTHER"
 838                         default y
 839
 840                 config KERNEL_CFS_BANDWIDTH
 841                         bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
 842                         default y
 843                         depends on KERNEL_FAIR_GROUP_SCHED
 844                         help
 845                           This option allows users to define CPU bandwidth rates (limits) for
 846                           tasks running within the fair group scheduler.  Groups with no limit
 847                           set are considered to be unconstrained and will run with no
 848                           restriction.
 849                           See tip/Documentation/scheduler/sched-bwc.txt for more information.
 850
 851                 config KERNEL_RT_GROUP_SCHED
 852                         bool "Group scheduling for SCHED_RR/FIFO"
 853                         default y
 854                         help
 855                           This feature lets you explicitly allocate real CPU bandwidth
 856                           to task groups. If enabled, it will also make it impossible to
 857                           schedule realtime tasks for non-root users until you allocate
 858                           realtime bandwidth for them.
 859
 860         endif
 861
 862         config KERNEL_BLK_CGROUP
 863                 bool "Block IO controller"
 864                 default y
 865                 help
 866                   Generic block IO controller cgroup interface. This is the common
 867                   cgroup interface which should be used by various IO controlling
 868                   policies.
 869
 870                   Currently, CFQ IO scheduler uses it to recognize task groups and
 871                   control disk bandwidth allocation (proportional time slice allocation)
 872                   to such task groups. It is also used by bio throttling logic in
 873                   block layer to implement upper limit in IO rates on a device.
 874
 875                   This option only enables generic Block IO controller infrastructure.
 876                   One needs to also enable actual IO controlling logic/policy. For
 877                   enabling proportional weight division of disk bandwidth in CFQ, set
 878                   CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
 879                   CONFIG_BLK_DEV_THROTTLING=y.
 880
 881         if KERNEL_BLK_CGROUP
 882
 883                 config KERNEL_CFQ_GROUP_IOSCHED
 884                         bool "Proportional weight of disk bandwidth in CFQ"
 885
 886                 config KERNEL_BLK_DEV_THROTTLING
 887                         bool "Enable throttling policy"
 888                         default y
 889
 890                 config KERNEL_BLK_DEV_THROTTLING_LOW
 891                         bool "Block throttling .low limit interface support (EXPERIMENTAL)"
 892                         depends on KERNEL_BLK_DEV_THROTTLING
 893         endif
 894
 895         config KERNEL_DEBUG_BLK_CGROUP
 896                 bool "Enable Block IO controller debugging"
 897                 default n
 898                 depends on KERNEL_BLK_CGROUP
 899                 help
 900                   Enable some debugging help. Currently it exports additional stat
 901                   files in a cgroup which can be useful for debugging.
 902
 903         config KERNEL_NET_CLS_CGROUP
 904                 bool "legacy Control Group Classifier"
 905                 default n
 906
 907         config KERNEL_CGROUP_NET_CLASSID
 908                 bool "legacy Network classid cgroup"
 909                 default n
 910
 911         config KERNEL_CGROUP_NET_PRIO
 912                 bool "legacy Network priority cgroup"
 913                 default n
 914
 915 endif
 916
 917 #
 918 # Namespace support symbols
 919 #
 920
 921 config KERNEL_NAMESPACES
 922         bool "Enable kernel namespaces"
 923         default y if !SMALL_FLASH
 924
 925 if KERNEL_NAMESPACES
 926
 927         config KERNEL_UTS_NS
 928                 bool "UTS namespace"
 929                 default y
 930                 help
 931                   In this namespace, tasks see different info provided
 932                   with the uname() system call.
 933
 934         config KERNEL_IPC_NS
 935                 bool "IPC namespace"
 936                 default y
 937                 help
 938                   In this namespace, tasks work with IPC ids which correspond to
 939                   different IPC objects in different namespaces.
 940
 941         config KERNEL_USER_NS
 942                 bool "User namespace (EXPERIMENTAL)"
 943                 default y
 944                 help
 945                   This allows containers, i.e. vservers, to use user namespaces
 946                   to provide different user info for different servers.
 947
 948         config KERNEL_PID_NS
 949                 bool "PID Namespaces"
 950                 default y
 951                 help
 952                   Support process id namespaces. This allows having multiple
 953                   processes with the same pid as long as they are in different
 954                   pid namespaces. This is a building block of containers.
 955
 956         config KERNEL_NET_NS
 957                 bool "Network namespace"
 958                 default y
 959                 help
 960                   Allow user space to create what appear to be multiple instances
 961                   of the network stack.
 962
 963 endif
 964
 965 config KERNEL_DEVPTS_MULTIPLE_INSTANCES
 966         bool "Support multiple instances of devpts"
 967         default y if !SMALL_FLASH
 968         help
 969           Enable support for multiple instances of devpts filesystem.
 970           If you want to have isolated PTY namespaces (eg: in containers),
 971           say Y here. Otherwise, say N. If enabled, each mount of devpts
 972           filesystem with the '-o newinstance' option will create an
 973           independent PTY namespace.
 974
 975 config KERNEL_POSIX_MQUEUE
 976         bool "POSIX Message Queues"
 977         default y if !SMALL_FLASH
 978         help
 979           POSIX variant of message queues is a part of IPC. In POSIX message
 980           queues every message has a priority which decides about succession
 981           of receiving it by a process. If you want to compile and run
 982           programs written e.g. for Solaris with use of its POSIX message
 983           queues (functions mq_*) say Y here.
 984
 985           POSIX message queues are visible as a filesystem called 'mqueue'
 986           and can be mounted somewhere if you want to do filesystem
 987           operations on message queues.
 988
 989
 990 config KERNEL_SECCOMP_FILTER
 991         bool
 992         default y if !SMALL_FLASH
 993
 994 config KERNEL_SECCOMP
 995         bool "Enable seccomp support"
 996                 depends on !(TARGET_uml)
 997                 select KERNEL_SECCOMP_FILTER
 998                 default y if !SMALL_FLASH
 999                 help
1000                   Build kernel with support for seccomp.
1001
1002 #
1003 # IPv4 configuration
1004 #
1005
1006 config KERNEL_IP_MROUTE
1007         bool "Enable IPv4 multicast routing"
1008         default y
1009         help
1010           Multicast routing requires a multicast routing daemon in
1011           addition to kernel support.
1012
1013 if KERNEL_IP_MROUTE
1014
1015         config KERNEL_IP_MROUTE_MULTIPLE_TABLES
1016                 def_bool y
1017
1018         config KERNEL_IP_PIMSM_V1
1019                 def_bool y
1020
1021         config KERNEL_IP_PIMSM_V2
1022                 def_bool y
1023
1024 endif
1025
1026 #
1027 # IPv6 configuration
1028 #
1029
1030 config KERNEL_IPV6
1031         def_bool IPV6
1032
1033 if KERNEL_IPV6
1034
1035         config KERNEL_IPV6_MULTIPLE_TABLES
1036                 def_bool y
1037
1038         config KERNEL_IPV6_SUBTREES
1039                 def_bool y
1040
1041         config KERNEL_IPV6_MROUTE
1042                 bool "Enable IPv6 multicast routing"
1043                 default y
1044                 help
1045                   Multicast routing requires a multicast routing daemon in
1046                   addition to kernel support.
1047
1048         if KERNEL_IPV6_MROUTE
1049
1050                 config KERNEL_IPV6_MROUTE_MULTIPLE_TABLES
1051                         def_bool y
1052
1053                 config KERNEL_IPV6_PIMSM_V2
1054                         def_bool y
1055
1056         endif
1057
1058         config KERNEL_IPV6_SEG6_LWTUNNEL
1059                 bool "Enable support for lightweight tunnels"
1060                 default y if !SMALL_FLASH
1061                 help
1062                   Using lwtunnel (needed for IPv6 segment routing) requires ip-full package.
1063
1064         config KERNEL_LWTUNNEL_BPF
1065                 def_bool n
1066
1067 endif
1068
1069 #
1070 # Miscellaneous network configuration
1071 #
1072
1073 config KERNEL_NET_L3_MASTER_DEV
1074         bool "L3 Master device support"
1075         help
1076           This module provides glue between core networking code and device
1077           drivers to support L3 master devices like VRF.
1078
1079 #
1080 # NFS related symbols
1081 #
1082 config KERNEL_IP_PNP
1083         bool "Compile the kernel with rootfs on NFS"
1084         help
1085            If you want to make your kernel boot off a NFS server as root
1086            filesystem, select Y here.
1087
1088 if KERNEL_IP_PNP
1089
1090         config KERNEL_IP_PNP_DHCP
1091                 def_bool y
1092
1093         config KERNEL_IP_PNP_BOOTP
1094                 def_bool n
1095
1096         config KERNEL_IP_PNP_RARP
1097                 def_bool n
1098
1099         config KERNEL_NFS_FS
1100                 def_bool y
1101
1102         config KERNEL_NFS_V2
1103                 def_bool y
1104
1105         config KERNEL_NFS_V3
1106                 def_bool y
1107
1108         config KERNEL_ROOT_NFS
1109                 def_bool y
1110
1111 endif
1112
1113 menu "Filesystem ACL and attr support options"
1114         config USE_FS_ACL_ATTR
1115                 bool "Use filesystem ACL and attr support by default"
1116                 default n
1117                 help
1118                   Make using ACLs (e.g. POSIX ACL, NFSv4 ACL) the default
1119                   for kernel and packages, except tmpfs, flash filesystems,
1120                   and old NFS.  Also enable userspace extended attribute support
1121                   by default.  (OpenWrt already has an expection it will be
1122                   present in the kernel).
1123
1124         config KERNEL_FS_POSIX_ACL
1125                 bool "Enable POSIX ACL support"
1126                 default y if USE_FS_ACL_ATTR
1127
1128         config KERNEL_BTRFS_FS_POSIX_ACL
1129                 bool "Enable POSIX ACL for BtrFS Filesystems"
1130                 select KERNEL_FS_POSIX_ACL
1131                 default y if USE_FS_ACL_ATTR
1132
1133         config KERNEL_EXT4_FS_POSIX_ACL
1134                 bool "Enable POSIX ACL for Ext4 Filesystems"
1135                 select KERNEL_FS_POSIX_ACL
1136                 default y if USE_FS_ACL_ATTR
1137
1138         config KERNEL_F2FS_FS_POSIX_ACL
1139                 bool "Enable POSIX ACL for F2FS Filesystems"
1140                 select KERNEL_FS_POSIX_ACL
1141                 default n
1142
1143         config KERNEL_JFFS2_FS_POSIX_ACL
1144                 bool "Enable POSIX ACL for JFFS2 Filesystems"
1145                 select KERNEL_FS_POSIX_ACL
1146                 default n
1147
1148         config KERNEL_TMPFS_POSIX_ACL
1149                 bool "Enable POSIX ACL for TMPFS Filesystems"
1150                 select KERNEL_FS_POSIX_ACL
1151                 default n
1152
1153         config KERNEL_CIFS_ACL
1154                 bool "Enable CIFS ACLs"
1155                 select KERNEL_FS_POSIX_ACL
1156                 default y if USE_FS_ACL_ATTR
1157
1158         config KERNEL_HFS_FS_POSIX_ACL
1159                 bool "Enable POSIX ACL for HFS Filesystems"
1160                 select KERNEL_FS_POSIX_ACL
1161                 default y if USE_FS_ACL_ATTR
1162
1163         config KERNEL_HFSPLUS_FS_POSIX_ACL
1164                 bool "Enable POSIX ACL for HFS+ Filesystems"
1165                 select KERNEL_FS_POSIX_ACL
1166                 default y if USE_FS_ACL_ATTR
1167
1168         config KERNEL_NFS_ACL_SUPPORT
1169                 bool "Enable ACLs for NFS"
1170                 default y if USE_FS_ACL_ATTR
1171
1172         config KERNEL_NFS_V3_ACL_SUPPORT
1173                 bool "Enable ACLs for NFSv3"
1174                 default n
1175
1176         config KERNEL_NFSD_V2_ACL_SUPPORT
1177                 bool "Enable ACLs for NFSDv2"
1178                 default n
1179
1180         config KERNEL_NFSD_V3_ACL_SUPPORT
1181                 bool "Enable ACLs for NFSDv3"
1182                 default n
1183
1184         config KERNEL_REISER_FS_POSIX_ACL
1185                 bool "Enable POSIX ACLs for ReiserFS"
1186                 select KERNEL_FS_POSIX_ACL
1187                 default y if USE_FS_ACL_ATTR
1188
1189         config KERNEL_XFS_POSIX_ACL
1190                 bool "Enable POSIX ACLs for XFS"
1191                 select KERNEL_FS_POSIX_ACL
1192                 default y if USE_FS_ACL_ATTR
1193
1194         config KERNEL_JFS_POSIX_ACL
1195                 bool "Enable POSIX ACLs for JFS"
1196                 select KERNEL_FS_POSIX_ACL
1197                 default y if USE_FS_ACL_ATTR
1198
1199 endmenu
1200
1201 config KERNEL_DEVMEM
1202         bool "/dev/mem virtual device support"
1203         help
1204           Say Y here if you want to support the /dev/mem device.
1205           The /dev/mem device is used to access areas of physical
1206           memory.
1207
1208 config KERNEL_DEVKMEM
1209         bool "/dev/kmem virtual device support"
1210         help
1211           Say Y here if you want to support the /dev/kmem device. The
1212           /dev/kmem device is rarely used, but can be used for certain
1213           kind of kernel debugging operations.
1214
1215 config KERNEL_SQUASHFS_FRAGMENT_CACHE_SIZE
1216         int "Number of squashfs fragments cached"
1217         default 2 if (SMALL_FLASH && !LOW_MEMORY_FOOTPRINT)
1218         default 3
1219
1220 config KERNEL_SQUASHFS_XATTR
1221         bool "Squashfs XATTR support"
1222
1223 #
1224 # compile optimization setting
1225 #
1226 choice
1227         prompt "Compiler optimization level"
1228         default KERNEL_CC_OPTIMIZE_FOR_SIZE if SMALL_FLASH
1229
1230 config KERNEL_CC_OPTIMIZE_FOR_PERFORMANCE
1231         bool "Optimize for performance"
1232         help
1233           This is the default optimization level for the kernel, building
1234           with the "-O2" compiler flag for best performance and most
1235           helpful compile-time warnings.
1236
1237 config KERNEL_CC_OPTIMIZE_FOR_SIZE
1238         bool "Optimize for size"
1239         help
1240           Enabling this option will pass "-Os" instead of "-O2" to
1241           your compiler resulting in a smaller kernel.
1242
1243 endchoice
1244
1245 config KERNEL_AUDIT
1246         bool "Auditing support"
1247
1248 config KERNEL_SECURITY
1249         bool "Enable different security models"
1250
1251 config KERNEL_SECURITY_NETWORK
1252         bool "Socket and Networking Security Hooks"
1253         select KERNEL_SECURITY
1254
1255 config KERNEL_SECURITY_SELINUX
1256         bool "NSA SELinux Support"
1257         select KERNEL_SECURITY_NETWORK
1258         select KERNEL_AUDIT
1259
1260 config KERNEL_SECURITY_SELINUX_BOOTPARAM
1261         bool "NSA SELinux boot parameter"
1262         depends on KERNEL_SECURITY_SELINUX
1263         default y
1264
1265 config KERNEL_SECURITY_SELINUX_DISABLE
1266         bool "NSA SELinux runtime disable"
1267         depends on KERNEL_SECURITY_SELINUX
1268
1269 config KERNEL_SECURITY_SELINUX_DEVELOP
1270         bool "NSA SELinux Development Support"
1271         depends on KERNEL_SECURITY_SELINUX
1272         default y
1273
1274 config KERNEL_SECURITY_SELINUX_SIDTAB_HASH_BITS
1275         int
1276         depends on KERNEL_SECURITY_SELINUX
1277         default 9
1278
1279 config KERNEL_SECURITY_SELINUX_SID2STR_CACHE_SIZE
1280         int
1281         depends on KERNEL_SECURITY_SELINUX
1282         default 256
1283
1284 config KERNEL_LSM
1285         string
1286         default "lockdown,yama,loadpin,safesetid,integrity,selinux"
1287         depends on KERNEL_SECURITY_SELINUX
1288
1289 config KERNEL_EXT4_FS_SECURITY
1290         bool "Ext4 Security Labels"
1291
1292 config KERNEL_F2FS_FS_SECURITY
1293         bool "F2FS Security Labels"
1294
1295 config KERNEL_UBIFS_FS_SECURITY
1296         bool "UBIFS Security Labels"
1297
1298 config KERNEL_JFFS2_FS_SECURITY
1299         bool "JFFS2 Security Labels"