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_CRASHLOG
  28         bool "Crash logging"
  29         depends on !(arm || powerpc || sparc || TARGET_uml || i386 || x86_64)
  30         default y
  31
  32 config KERNEL_SWAP
  33         bool "Support for paging of anonymous memory (swap)"
  34         default y if !SMALL_FLASH
  35
  36 config KERNEL_PROC_STRIPPED
  37         bool "Strip non-essential /proc functionality to reduce code size"
  38         default y if SMALL_FLASH
  39
  40 config KERNEL_DEBUG_FS
  41         bool "Compile the kernel with debug filesystem enabled"
  42         default y
  43         help
  44           debugfs is a virtual file system that kernel developers use to put
  45           debugging files into. Enable this option to be able to read and
  46           write to these files. Many common debugging facilities, such as
  47           ftrace, require the existence of debugfs.
  48
  49 config KERNEL_MIPS_FP_SUPPORT
  50         bool
  51         default y if TARGET_pistachio
  52
  53 config KERNEL_ARM_PMU
  54         bool
  55         default n
  56         depends on (arm || aarch64)
  57
  58 config KERNEL_X86_VSYSCALL_EMULATION
  59         bool "Enable vsyscall emulation"
  60         default n
  61         depends on x86_64
  62         help
  63           This enables emulation of the legacy vsyscall page.  Disabling
  64           it is roughly equivalent to booting with vsyscall=none, except
  65           that it will also disable the helpful warning if a program
  66           tries to use a vsyscall.  With this option set to N, offending
  67           programs will just segfault, citing addresses of the form
  68           0xffffffffff600?00.
  69
  70           This option is required by many programs built before 2013, and
  71           care should be used even with newer programs if set to N.
  72
  73           Disabling this option saves about 7K of kernel size and
  74           possibly 4K of additional runtime pagetable memory.
  75
  76 config KERNEL_PERF_EVENTS
  77         bool "Compile the kernel with performance events and counters"
  78         default n
  79         select KERNEL_ARM_PMU if (arm || aarch64)
  80
  81 config KERNEL_PROFILING
  82         bool "Compile the kernel with profiling enabled"
  83         default n
  84         select KERNEL_PERF_EVENTS
  85         help
  86           Enable the extended profiling support mechanisms used by profilers such
  87           as OProfile.
  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_AIO
 431         bool "Compile the kernel with asynchronous IO support"
 432         default y if !SMALL_FLASH
 433
 434 config KERNEL_IO_URING
 435         bool "Compile the kernel with io_uring support"
 436         default y if !SMALL_FLASH
 437
 438 config KERNEL_FHANDLE
 439         bool "Compile the kernel with support for fhandle syscalls"
 440         default y if !SMALL_FLASH
 441
 442 config KERNEL_FANOTIFY
 443         bool "Compile the kernel with modern file notification support"
 444         default y if !SMALL_FLASH
 445
 446 config KERNEL_BLK_DEV_BSG
 447         bool "Compile the kernel with SCSI generic v4 support for any block device"
 448         default n
 449
 450 config KERNEL_TRANSPARENT_HUGEPAGE
 451         bool
 452
 453 choice
 454         prompt "Transparent Hugepage Support sysfs defaults"
 455         depends on KERNEL_TRANSPARENT_HUGEPAGE
 456         default KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
 457
 458         config KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
 459                 bool "always"
 460
 461         config KERNEL_TRANSPARENT_HUGEPAGE_MADVISE
 462                 bool "madvise"
 463 endchoice
 464
 465 config KERNEL_HUGETLBFS
 466         bool
 467
 468 config KERNEL_HUGETLB_PAGE
 469         bool "Compile the kernel with HugeTLB support"
 470         select KERNEL_TRANSPARENT_HUGEPAGE
 471         select KERNEL_HUGETLBFS
 472         default n
 473
 474 config KERNEL_MAGIC_SYSRQ
 475         bool "Compile the kernel with SysRq support"
 476         default y
 477
 478 config KERNEL_DEBUG_PINCTRL
 479         bool "Compile the kernel with pinctrl debugging"
 480         select KERNEL_DEBUG_KERNEL
 481
 482 config KERNEL_DEBUG_GPIO
 483         bool "Compile the kernel with gpio debugging"
 484         select KERNEL_DEBUG_KERNEL
 485
 486 config KERNEL_COREDUMP
 487         bool
 488
 489 config KERNEL_ELF_CORE
 490         bool "Enable process core dump support"
 491         select KERNEL_COREDUMP
 492         default y if !SMALL_FLASH
 493
 494 config KERNEL_PROVE_LOCKING
 495         bool "Enable kernel lock checking"
 496         select KERNEL_DEBUG_KERNEL
 497         default n
 498
 499 config KERNEL_SOFTLOCKUP_DETECTOR
 500         bool "Compile the kernel with detect Soft Lockups"
 501         depends on KERNEL_DEBUG_KERNEL
 502         help
 503           Say Y here to enable the kernel to act as a watchdog to detect
 504           soft lockups.
 505
 506           Softlockups are bugs that cause the kernel to loop in kernel
 507           mode for more than 20 seconds, without giving other tasks a
 508           chance to run.  The current stack trace is displayed upon
 509           detection and the system will stay locked up.
 510
 511 config KERNEL_DETECT_HUNG_TASK
 512         bool "Compile the kernel with detect Hung Tasks"
 513         depends on KERNEL_DEBUG_KERNEL
 514         default KERNEL_SOFTLOCKUP_DETECTOR
 515         help
 516           Say Y here to enable the kernel to detect "hung tasks",
 517           which are bugs that cause the task to be stuck in
 518           uninterruptible "D" state indefinitely.
 519
 520           When a hung task is detected, the kernel will print the
 521           current stack trace (which you should report), but the
 522           task will stay in uninterruptible state. If lockdep is
 523           enabled then all held locks will also be reported. This
 524           feature has negligible overhead.
 525
 526 config KERNEL_WQ_WATCHDOG
 527         bool "Compile the kernel with detect Workqueue Stalls"
 528         depends on KERNEL_DEBUG_KERNEL
 529         help
 530           Say Y here to enable stall detection on workqueues.  If a
 531           worker pool doesn't make forward progress on a pending work
 532           item for over a given amount of time, 30s by default, a
 533           warning message is printed along with dump of workqueue
 534           state.  This can be configured through kernel parameter
 535           "workqueue.watchdog_thresh" and its sysfs counterpart.
 536
 537 config KERNEL_DEBUG_ATOMIC_SLEEP
 538         bool "Compile the kernel with sleep inside atomic section checking"
 539         depends on KERNEL_DEBUG_KERNEL
 540         help
 541           If you say Y here, various routines which may sleep will become very
 542           noisy if they are called inside atomic sections: when a spinlock is
 543           held, inside an rcu read side critical section, inside preempt disabled
 544           sections, inside an interrupt, etc...
 545
 546 config KERNEL_DEBUG_VM
 547         bool "Compile the kernel with debug VM"
 548         depends on KERNEL_DEBUG_KERNEL
 549         help
 550           Enable this to turn on extended checks in the virtual-memory system
 551           that may impact performance.
 552
 553           If unsure, say N.
 554
 555 config KERNEL_PRINTK_TIME
 556         bool "Enable printk timestamps"
 557         default y
 558
 559 config KERNEL_SLUB_DEBUG
 560         bool
 561
 562 config KERNEL_SLUB_DEBUG_ON
 563         bool
 564
 565 config KERNEL_SLABINFO
 566         select KERNEL_SLUB_DEBUG
 567         select KERNEL_SLUB_DEBUG_ON
 568         bool "Enable /proc slab debug info"
 569
 570 config KERNEL_PROC_PAGE_MONITOR
 571         bool "Enable /proc page monitoring"
 572
 573 config KERNEL_RELAY
 574         bool
 575
 576 config KERNEL_KEXEC
 577         bool "Enable kexec support"
 578
 579 config KERNEL_PROC_VMCORE
 580         bool
 581
 582 config KERNEL_PROC_KCORE
 583         bool
 584
 585 config KERNEL_CRASH_DUMP
 586         depends on i386 || x86_64 || arm || armeb
 587         select KERNEL_KEXEC
 588         select KERNEL_PROC_VMCORE
 589         select KERNEL_PROC_KCORE
 590         bool "Enable support for kexec crashdump"
 591         default y
 592
 593 config USE_RFKILL
 594         bool "Enable rfkill support"
 595         default RFKILL_SUPPORT
 596
 597 config USE_SPARSE
 598         bool "Enable sparse check during kernel build"
 599         default n
 600
 601 config KERNEL_DEVTMPFS
 602         bool "Compile the kernel with device tmpfs enabled"
 603         default n
 604         help
 605           devtmpfs is a simple, kernel-managed /dev filesystem. The kernel creates
 606           devices nodes for all registered devices to simplify boot, but leaves more
 607           complex tasks to userspace (e.g. udev).
 608
 609 if KERNEL_DEVTMPFS
 610
 611         config KERNEL_DEVTMPFS_MOUNT
 612                 bool "Automatically mount devtmpfs after root filesystem is mounted"
 613                 default n
 614
 615 endif
 616
 617 config KERNEL_KEYS
 618         bool "Enable kernel access key retention support"
 619         default !SMALL_FLASH
 620
 621 config KERNEL_PERSISTENT_KEYRINGS
 622         bool "Enable kernel persistent keyrings"
 623         depends on KERNEL_KEYS
 624         default n
 625
 626 config KERNEL_KEYS_REQUEST_CACHE
 627         bool "Enable temporary caching of the last request_key() result"
 628         depends on KERNEL_KEYS
 629         default n
 630
 631 config KERNEL_BIG_KEYS
 632         bool "Enable large payload keys on kernel keyrings"
 633         depends on KERNEL_KEYS
 634         default n
 635
 636 #
 637 # CGROUP support symbols
 638 #
 639
 640 config KERNEL_CGROUPS
 641         bool "Enable kernel cgroups"
 642         default y if !SMALL_FLASH
 643
 644 if KERNEL_CGROUPS
 645
 646         config KERNEL_CGROUP_DEBUG
 647                 bool "Example debug cgroup subsystem"
 648                 default n
 649                 help
 650                   This option enables a simple cgroup subsystem that
 651                   exports useful debugging information about the cgroups
 652                   framework.
 653
 654         config KERNEL_FREEZER
 655                 bool
 656
 657         config KERNEL_CGROUP_FREEZER
 658                 bool "legacy Freezer cgroup subsystem"
 659                 default n
 660                 select KERNEL_FREEZER
 661                 help
 662                   Provides a way to freeze and unfreeze all tasks in a
 663                   cgroup.
 664                   (legacy cgroup1-only controller, in cgroup2 freezer
 665                   is integrated in the Memory controller)
 666
 667         config KERNEL_CGROUP_DEVICE
 668                 bool "legacy Device controller for cgroups"
 669                 default n
 670                 help
 671                   Provides a cgroup implementing whitelists for devices which
 672                   a process in the cgroup can mknod or open.
 673                   (legacy cgroup1-only controller)
 674
 675         config KERNEL_CGROUP_HUGETLB
 676                 bool "HugeTLB controller"
 677                 default n
 678                 select KERNEL_HUGETLB_PAGE
 679
 680         config KERNEL_CGROUP_PIDS
 681                 bool "PIDs cgroup subsystem"
 682                 default y
 683                 help
 684                   Provides enforcement of process number limits in the scope of a
 685                   cgroup.
 686
 687         config KERNEL_CGROUP_RDMA
 688                 bool "RDMA controller for cgroups"
 689                 default y
 690
 691         config KERNEL_CGROUP_BPF
 692                 bool "Support for eBPF programs attached to cgroups"
 693                 default y
 694
 695         config KERNEL_CPUSETS
 696                 bool "Cpuset support"
 697                 default y
 698                 help
 699                   This option will let you create and manage CPUSETs which
 700                   allow dynamically partitioning a system into sets of CPUs and
 701                   Memory Nodes and assigning tasks to run only within those sets.
 702                   This is primarily useful on large SMP or NUMA systems.
 703
 704         config KERNEL_PROC_PID_CPUSET
 705                 bool "Include legacy /proc/<pid>/cpuset file"
 706                 default n
 707                 depends on KERNEL_CPUSETS
 708
 709         config KERNEL_CGROUP_CPUACCT
 710                 bool "Simple CPU accounting cgroup subsystem"
 711                 default y
 712                 help
 713                   Provides a simple Resource Controller for monitoring the
 714                   total CPU consumed by the tasks in a cgroup.
 715
 716         config KERNEL_RESOURCE_COUNTERS
 717                 bool "Resource counters"
 718                 default y
 719                 help
 720                   This option enables controller independent resource accounting
 721                   infrastructure that works with cgroups.
 722
 723         config KERNEL_MM_OWNER
 724                 bool
 725                 default y if KERNEL_MEMCG
 726
 727         config KERNEL_MEMCG
 728                 bool "Memory Resource Controller for Control Groups"
 729                 default y
 730                 select KERNEL_FREEZER
 731                 depends on KERNEL_RESOURCE_COUNTERS || !LINUX_3_18
 732                 help
 733                   Provides a memory resource controller that manages both anonymous
 734                   memory and page cache. (See Documentation/cgroups/memory.txt)
 735
 736                   Note that setting this option increases fixed memory overhead
 737                   associated with each page of memory in the system. By this,
 738                   20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
 739                   usage tracking struct at boot. Total amount of this is printed out
 740                   at boot.
 741
 742                   Only enable when you're ok with these tradeoffs and really
 743                   sure you need the memory resource controller. Even when you enable
 744                   this, you can set "cgroup_disable=memory" at your boot option to
 745                   disable memory resource controller and you can avoid overheads
 746                   (but lose benefits of memory resource controller).
 747
 748                   This config option also selects MM_OWNER config option, which
 749                   could in turn add some fork/exit overhead.
 750
 751         config KERNEL_MEMCG_SWAP
 752                 bool "Memory Resource Controller Swap Extension"
 753                 default y
 754                 depends on KERNEL_MEMCG
 755                 help
 756                   Add swap management feature to memory resource controller. When you
 757                   enable this, you can limit mem+swap usage per cgroup. In other words,
 758                   when you disable this, memory resource controller has no cares to
 759                   usage of swap...a process can exhaust all of the swap. This extension
 760                   is useful when you want to avoid exhaustion swap but this itself
 761                   adds more overheads and consumes memory for remembering information.
 762                   Especially if you use 32bit system or small memory system, please
 763                   be careful about enabling this. When memory resource controller
 764                   is disabled by boot option, this will be automatically disabled and
 765                   there will be no overhead from this. Even when you set this config=y,
 766                   if boot option "swapaccount=0" is set, swap will not be accounted.
 767                   Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
 768                   size is 4096bytes, 512k per 1Gbytes of swap.
 769
 770         config KERNEL_MEMCG_SWAP_ENABLED
 771                 bool "Memory Resource Controller Swap Extension enabled by default"
 772                 default n
 773                 depends on KERNEL_MEMCG_SWAP
 774                 help
 775                   Memory Resource Controller Swap Extension comes with its price in
 776                   a bigger memory consumption. General purpose distribution kernels
 777                   which want to enable the feature but keep it disabled by default
 778                   and let the user enable it by swapaccount boot command line
 779                   parameter should have this option unselected.
 780
 781                   Those who want to have the feature enabled by default should
 782                   select this option (if, for some reason, they need to disable it,
 783                   then swapaccount=0 does the trick).
 784
 785
 786         config KERNEL_MEMCG_KMEM
 787                 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
 788                 default y
 789                 depends on KERNEL_MEMCG
 790                 help
 791                   The Kernel Memory extension for Memory Resource Controller can limit
 792                   the amount of memory used by kernel objects in the system. Those are
 793                   fundamentally different from the entities handled by the standard
 794                   Memory Controller, which are page-based, and can be swapped. Users of
 795                   the kmem extension can use it to guarantee that no group of processes
 796                   will ever exhaust kernel resources alone.
 797
 798         config KERNEL_CGROUP_PERF
 799                 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
 800                 select KERNEL_PERF_EVENTS
 801                 default n
 802                 help
 803                   This option extends the per-cpu mode to restrict monitoring to
 804                   threads which belong to the cgroup specified and run on the
 805                   designated cpu.
 806
 807         menuconfig KERNEL_CGROUP_SCHED
 808                 bool "Group CPU scheduler"
 809                 default y
 810                 help
 811                   This feature lets CPU scheduler recognize task groups and control CPU
 812                   bandwidth allocation to such task groups. It uses cgroups to group
 813                   tasks.
 814
 815         if KERNEL_CGROUP_SCHED
 816
 817                 config KERNEL_FAIR_GROUP_SCHED
 818                         bool "Group scheduling for SCHED_OTHER"
 819                         default y
 820
 821                 config KERNEL_CFS_BANDWIDTH
 822                         bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
 823                         default y
 824                         depends on KERNEL_FAIR_GROUP_SCHED
 825                         help
 826                           This option allows users to define CPU bandwidth rates (limits) for
 827                           tasks running within the fair group scheduler.  Groups with no limit
 828                           set are considered to be unconstrained and will run with no
 829                           restriction.
 830                           See tip/Documentation/scheduler/sched-bwc.txt for more information.
 831
 832                 config KERNEL_RT_GROUP_SCHED
 833                         bool "Group scheduling for SCHED_RR/FIFO"
 834                         default y
 835                         help
 836                           This feature lets you explicitly allocate real CPU bandwidth
 837                           to task groups. If enabled, it will also make it impossible to
 838                           schedule realtime tasks for non-root users until you allocate
 839                           realtime bandwidth for them.
 840
 841         endif
 842
 843         config KERNEL_BLK_CGROUP
 844                 bool "Block IO controller"
 845                 default y
 846                 help
 847                   Generic block IO controller cgroup interface. This is the common
 848                   cgroup interface which should be used by various IO controlling
 849                   policies.
 850
 851                   Currently, CFQ IO scheduler uses it to recognize task groups and
 852                   control disk bandwidth allocation (proportional time slice allocation)
 853                   to such task groups. It is also used by bio throttling logic in
 854                   block layer to implement upper limit in IO rates on a device.
 855
 856                   This option only enables generic Block IO controller infrastructure.
 857                   One needs to also enable actual IO controlling logic/policy. For
 858                   enabling proportional weight division of disk bandwidth in CFQ, set
 859                   CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
 860                   CONFIG_BLK_DEV_THROTTLING=y.
 861
 862         if KERNEL_BLK_CGROUP
 863
 864                 config KERNEL_CFQ_GROUP_IOSCHED
 865                         bool "Proportional weight of disk bandwidth in CFQ"
 866
 867                 config KERNEL_BLK_DEV_THROTTLING
 868                         bool "Enable throttling policy"
 869                         default y
 870
 871                 config KERNEL_BLK_DEV_THROTTLING_LOW
 872                         bool "Block throttling .low limit interface support (EXPERIMENTAL)"
 873                         depends on KERNEL_BLK_DEV_THROTTLING
 874         endif
 875
 876         config KERNEL_DEBUG_BLK_CGROUP
 877                 bool "Enable Block IO controller debugging"
 878                 default n
 879                 depends on KERNEL_BLK_CGROUP
 880                 help
 881                   Enable some debugging help. Currently it exports additional stat
 882                   files in a cgroup which can be useful for debugging.
 883
 884         config KERNEL_NET_CLS_CGROUP
 885                 bool "legacy Control Group Classifier"
 886                 default n
 887
 888         config KERNEL_CGROUP_NET_CLASSID
 889                 bool "legacy Network classid cgroup"
 890                 default n
 891
 892         config KERNEL_CGROUP_NET_PRIO
 893                 bool "legacy Network priority cgroup"
 894                 default n
 895
 896 endif
 897
 898 #
 899 # Namespace support symbols
 900 #
 901
 902 config KERNEL_NAMESPACES
 903         bool "Enable kernel namespaces"
 904         default y if !SMALL_FLASH
 905
 906 if KERNEL_NAMESPACES
 907
 908         config KERNEL_UTS_NS
 909                 bool "UTS namespace"
 910                 default y
 911                 help
 912                   In this namespace, tasks see different info provided
 913                   with the uname() system call.
 914
 915         config KERNEL_IPC_NS
 916                 bool "IPC namespace"
 917                 default y
 918                 help
 919                   In this namespace, tasks work with IPC ids which correspond to
 920                   different IPC objects in different namespaces.
 921
 922         config KERNEL_USER_NS
 923                 bool "User namespace (EXPERIMENTAL)"
 924                 default y
 925                 help
 926                   This allows containers, i.e. vservers, to use user namespaces
 927                   to provide different user info for different servers.
 928
 929         config KERNEL_PID_NS
 930                 bool "PID Namespaces"
 931                 default y
 932                 help
 933                   Support process id namespaces. This allows having multiple
 934                   processes with the same pid as long as they are in different
 935                   pid namespaces. This is a building block of containers.
 936
 937         config KERNEL_NET_NS
 938                 bool "Network namespace"
 939                 default y
 940                 help
 941                   Allow user space to create what appear to be multiple instances
 942                   of the network stack.
 943
 944 endif
 945
 946 config KERNEL_DEVPTS_MULTIPLE_INSTANCES
 947         bool "Support multiple instances of devpts"
 948         default y if !SMALL_FLASH
 949         help
 950           Enable support for multiple instances of devpts filesystem.
 951           If you want to have isolated PTY namespaces (eg: in containers),
 952           say Y here. Otherwise, say N. If enabled, each mount of devpts
 953           filesystem with the '-o newinstance' option will create an
 954           independent PTY namespace.
 955
 956 config KERNEL_POSIX_MQUEUE
 957         bool "POSIX Message Queues"
 958         default y if !SMALL_FLASH
 959         help
 960           POSIX variant of message queues is a part of IPC. In POSIX message
 961           queues every message has a priority which decides about succession
 962           of receiving it by a process. If you want to compile and run
 963           programs written e.g. for Solaris with use of its POSIX message
 964           queues (functions mq_*) say Y here.
 965
 966           POSIX message queues are visible as a filesystem called 'mqueue'
 967           and can be mounted somewhere if you want to do filesystem
 968           operations on message queues.
 969
 970
 971 config KERNEL_SECCOMP_FILTER
 972         bool
 973         default y if !SMALL_FLASH
 974
 975 config KERNEL_SECCOMP
 976         bool "Enable seccomp support"
 977                 depends on !(TARGET_uml)
 978                 select KERNEL_SECCOMP_FILTER
 979                 default y if !SMALL_FLASH
 980                 help
 981                   Build kernel with support for seccomp.
 982
 983 #
 984 # IPv4 configuration
 985 #
 986
 987 config KERNEL_IP_MROUTE
 988         bool "Enable IPv4 multicast routing"
 989         default y
 990         help
 991           Multicast routing requires a multicast routing daemon in
 992           addition to kernel support.
 993
 994 #
 995 # IPv6 configuration
 996 #
 997
 998 config KERNEL_IPV6
 999         def_bool IPV6
1000
1001 if KERNEL_IPV6
1002
1003         config KERNEL_IPV6_MULTIPLE_TABLES
1004                 def_bool y
1005
1006         config KERNEL_IPV6_SUBTREES
1007                 def_bool y
1008
1009         config KERNEL_IPV6_MROUTE
1010                 bool "Enable IPv6 multicast routing"
1011                 default y
1012                 help
1013                   Multicast routing requires a multicast routing daemon in
1014                   addition to kernel support.
1015
1016         config KERNEL_IPV6_PIMSM_V2
1017                 def_bool n
1018
1019         config KERNEL_IPV6_SEG6_LWTUNNEL
1020                 bool "Enable support for lightweight tunnels"
1021                 default y if !SMALL_FLASH
1022                 help
1023                   Using lwtunnel (needed for IPv6 segment routing) requires ip-full package.
1024
1025         config KERNEL_LWTUNNEL_BPF
1026                 def_bool n
1027
1028 endif
1029
1030 #
1031 # NFS related symbols
1032 #
1033 config KERNEL_IP_PNP
1034         bool "Compile the kernel with rootfs on NFS"
1035         help
1036            If you want to make your kernel boot off a NFS server as root
1037            filesystem, select Y here.
1038
1039 if KERNEL_IP_PNP
1040
1041         config KERNEL_IP_PNP_DHCP
1042                 def_bool y
1043
1044         config KERNEL_IP_PNP_BOOTP
1045                 def_bool n
1046
1047         config KERNEL_IP_PNP_RARP
1048                 def_bool n
1049
1050         config KERNEL_NFS_FS
1051                 def_bool y
1052
1053         config KERNEL_NFS_V2
1054                 def_bool y
1055
1056         config KERNEL_NFS_V3
1057                 def_bool y
1058
1059         config KERNEL_ROOT_NFS
1060                 def_bool y
1061
1062 endif
1063
1064 menu "Filesystem ACL and attr support options"
1065         config USE_FS_ACL_ATTR
1066                 bool "Use filesystem ACL and attr support by default"
1067                 default n
1068                 help
1069                   Make using ACLs (e.g. POSIX ACL, NFSv4 ACL) the default
1070                   for kernel and packages, except tmpfs, flash filesystems,
1071                   and old NFS.  Also enable userspace extended attribute support
1072                   by default.  (OpenWrt already has an expection it will be
1073                   present in the kernel).
1074
1075         config KERNEL_FS_POSIX_ACL
1076                 bool "Enable POSIX ACL support"
1077                 default y if USE_FS_ACL_ATTR
1078
1079         config KERNEL_BTRFS_FS_POSIX_ACL
1080                 bool "Enable POSIX ACL for BtrFS Filesystems"
1081                 select KERNEL_FS_POSIX_ACL
1082                 default y if USE_FS_ACL_ATTR
1083
1084         config KERNEL_EXT4_FS_POSIX_ACL
1085                 bool "Enable POSIX ACL for Ext4 Filesystems"
1086                 select KERNEL_FS_POSIX_ACL
1087                 default y if USE_FS_ACL_ATTR
1088
1089         config KERNEL_F2FS_FS_POSIX_ACL
1090                 bool "Enable POSIX ACL for F2FS Filesystems"
1091                 select KERNEL_FS_POSIX_ACL
1092                 default n
1093
1094         config KERNEL_JFFS2_FS_POSIX_ACL
1095                 bool "Enable POSIX ACL for JFFS2 Filesystems"
1096                 select KERNEL_FS_POSIX_ACL
1097                 default n
1098
1099         config KERNEL_TMPFS_POSIX_ACL
1100                 bool "Enable POSIX ACL for TMPFS Filesystems"
1101                 select KERNEL_FS_POSIX_ACL
1102                 default n
1103
1104         config KERNEL_CIFS_ACL
1105                 bool "Enable CIFS ACLs"
1106                 select KERNEL_FS_POSIX_ACL
1107                 default y if USE_FS_ACL_ATTR
1108
1109         config KERNEL_HFS_FS_POSIX_ACL
1110                 bool "Enable POSIX ACL for HFS Filesystems"
1111                 select KERNEL_FS_POSIX_ACL
1112                 default y if USE_FS_ACL_ATTR
1113
1114         config KERNEL_HFSPLUS_FS_POSIX_ACL
1115                 bool "Enable POSIX ACL for HFS+ Filesystems"
1116                 select KERNEL_FS_POSIX_ACL
1117                 default y if USE_FS_ACL_ATTR
1118
1119         config KERNEL_NFS_ACL_SUPPORT
1120                 bool "Enable ACLs for NFS"
1121                 default y if USE_FS_ACL_ATTR
1122
1123         config KERNEL_NFS_V3_ACL_SUPPORT
1124                 bool "Enable ACLs for NFSv3"
1125                 default n
1126
1127         config KERNEL_NFSD_V2_ACL_SUPPORT
1128                 bool "Enable ACLs for NFSDv2"
1129                 default n
1130
1131         config KERNEL_NFSD_V3_ACL_SUPPORT
1132                 bool "Enable ACLs for NFSDv3"
1133                 default n
1134
1135         config KERNEL_REISER_FS_POSIX_ACL
1136                 bool "Enable POSIX ACLs for ReiserFS"
1137                 select KERNEL_FS_POSIX_ACL
1138                 default y if USE_FS_ACL_ATTR
1139
1140         config KERNEL_XFS_POSIX_ACL
1141                 bool "Enable POSIX ACLs for XFS"
1142                 select KERNEL_FS_POSIX_ACL
1143                 default y if USE_FS_ACL_ATTR
1144
1145         config KERNEL_JFS_POSIX_ACL
1146                 bool "Enable POSIX ACLs for JFS"
1147                 select KERNEL_FS_POSIX_ACL
1148                 default y if USE_FS_ACL_ATTR
1149
1150 endmenu
1151
1152 config KERNEL_DEVMEM
1153         bool "/dev/mem virtual device support"
1154         help
1155           Say Y here if you want to support the /dev/mem device.
1156           The /dev/mem device is used to access areas of physical
1157           memory.
1158
1159 config KERNEL_DEVKMEM
1160         bool "/dev/kmem virtual device support"
1161         help
1162           Say Y here if you want to support the /dev/kmem device. The
1163           /dev/kmem device is rarely used, but can be used for certain
1164           kind of kernel debugging operations.
1165
1166 config KERNEL_SQUASHFS_FRAGMENT_CACHE_SIZE
1167         int "Number of squashfs fragments cached"
1168         default 2 if (SMALL_FLASH && !LOW_MEMORY_FOOTPRINT)
1169         default 3
1170
1171 config KERNEL_SQUASHFS_XATTR
1172         bool "Squashfs XATTR support"
1173
1174 #
1175 # compile optimization setting
1176 #
1177 choice
1178         prompt "Compiler optimization level"
1179         default KERNEL_CC_OPTIMIZE_FOR_SIZE if SMALL_FLASH
1180
1181 config KERNEL_CC_OPTIMIZE_FOR_PERFORMANCE
1182         bool "Optimize for performance"
1183         help
1184           This is the default optimization level for the kernel, building
1185           with the "-O2" compiler flag for best performance and most
1186           helpful compile-time warnings.
1187
1188 config KERNEL_CC_OPTIMIZE_FOR_SIZE
1189         bool "Optimize for size"
1190         help
1191           Enabling this option will pass "-Os" instead of "-O2" to
1192           your compiler resulting in a smaller kernel.
1193
1194 endchoice
1195
1196 config KERNEL_AUDIT
1197         bool "Auditing support"
1198
1199 config KERNEL_SECURITY
1200         bool "Enable different security models"
1201
1202 config KERNEL_SECURITY_NETWORK
1203         bool "Socket and Networking Security Hooks"
1204         select KERNEL_SECURITY
1205
1206 config KERNEL_SECURITY_SELINUX
1207         bool "NSA SELinux Support"
1208         select KERNEL_SECURITY_NETWORK
1209         select KERNEL_AUDIT
1210
1211 config KERNEL_SECURITY_SELINUX_BOOTPARAM
1212         bool "NSA SELinux boot parameter"
1213         depends on KERNEL_SECURITY_SELINUX
1214         default y
1215
1216 config KERNEL_SECURITY_SELINUX_DISABLE
1217         bool "NSA SELinux runtime disable"
1218         depends on KERNEL_SECURITY_SELINUX
1219
1220 config KERNEL_SECURITY_SELINUX_DEVELOP
1221         bool "NSA SELinux Development Support"
1222         depends on KERNEL_SECURITY_SELINUX
1223         default y
1224
1225 config KERNEL_SECURITY_SELINUX_SIDTAB_HASH_BITS
1226         int
1227         depends on KERNEL_SECURITY_SELINUX
1228         default 9
1229
1230 config KERNEL_SECURITY_SELINUX_SID2STR_CACHE_SIZE
1231         int
1232         depends on KERNEL_SECURITY_SELINUX
1233         default 256
1234
1235 config KERNEL_LSM
1236         string
1237         default "lockdown,yama,loadpin,safesetid,integrity,selinux"
1238         depends on KERNEL_SECURITY_SELINUX
1239
1240 config KERNEL_EXT4_FS_SECURITY
1241         bool "Ext4 Security Labels"
1242
1243 config KERNEL_F2FS_FS_SECURITY
1244         bool "F2FS Security Labels"
1245
1246 config KERNEL_UBIFS_FS_SECURITY
1247         bool "UBIFS Security Labels"
1248
1249 config KERNEL_JFFS2_FS_SECURITY
1250         bool "JFFS2 Security Labels"