1 # SPDX-License-Identifier: GPL-2.0-only
3 # Copyright (C) 2006-2014 OpenWrt.org
5 config KERNEL_BUILD_USER
6 string "Custom Kernel Build User Name"
7 default "builder" if BUILDBOT
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.
14 config KERNEL_BUILD_DOMAIN
15 string "Custom Kernel Build Domain Name"
16 default "buildhost" if BUILDBOT
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.
24 bool "Enable support for printk"
27 config KERNEL_CRASHLOG
29 depends on !(arm || powerpc || sparc || TARGET_uml || i386 || x86_64)
33 bool "Support for paging of anonymous memory (swap)"
34 default y if !SMALL_FLASH
36 config KERNEL_PROC_STRIPPED
37 bool "Strip non-essential /proc functionality to reduce code size"
38 default y if SMALL_FLASH
40 config KERNEL_DEBUG_FS
41 bool "Compile the kernel with debug filesystem enabled"
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.
49 config KERNEL_MIPS_FP_SUPPORT
51 default y if TARGET_pistachio
56 depends on (arm || aarch64)
58 config KERNEL_X86_VSYSCALL_EMULATION
59 bool "Enable vsyscall emulation"
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
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.
73 Disabling this option saves about 7K of kernel size and
74 possibly 4K of additional runtime pagetable memory.
76 config KERNEL_PERF_EVENTS
77 bool "Compile the kernel with performance events and counters"
79 select KERNEL_ARM_PMU if (arm || aarch64)
81 config KERNEL_PROFILING
82 bool "Compile the kernel with profiling enabled"
84 select KERNEL_PERF_EVENTS
86 Enable the extended profiling support mechanisms used by profilers such
90 bool "Compile the kernel with undefined behaviour sanity checker"
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).
98 config KERNEL_UBSAN_SANITIZE_ALL
99 bool "Enable instrumentation for the entire kernel"
100 depends on KERNEL_UBSAN
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
109 config KERNEL_UBSAN_ALIGNMENT
110 bool "Enable checking of pointers alignment"
111 depends on KERNEL_UBSAN
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.
117 config KERNEL_UBSAN_BOUNDS
118 bool "Perform array index bounds checking"
119 depends on KERNEL_UBSAN
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
127 config KERNEL_UBSAN_NULL
128 bool "Enable checking of null pointers"
129 depends on KERNEL_UBSAN
131 This option enables detection of memory accesses via a
134 config KERNEL_UBSAN_TRAP
135 bool "On Sanitizer warnings, abort the running kernel code"
136 depends on KERNEL_UBSAN
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.
148 bool "Compile the kernel with KASan: runtime memory debugger"
149 select KERNEL_SLUB_DEBUG
150 depends on (x86_64 || aarch64)
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).
163 config KERNEL_KASAN_EXTRA
164 bool "KAsan: extra checks"
165 depends on KERNEL_KASAN && KERNEL_DEBUG_KERNEL
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
171 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 has more
174 config KERNEL_KASAN_GENERIC
177 config KERNEL_KASAN_SW_TAGS
182 prompt "Instrumentation type"
183 depends on KERNEL_KASAN
184 default KERNEL_KASAN_OUTLINE
186 config KERNEL_KASAN_OUTLINE
187 bool "Outline instrumentation"
189 Before every memory access compiler insert function call
190 __asan_load*/__asan_store*. These functions performs check
191 of shadow memory. This is slower than inline instrumentation,
192 however it doesn't bloat size of kernel's .text section so
195 config KERNEL_KASAN_INLINE
196 bool "Inline instrumentation"
198 Compiler directly inserts code checking shadow memory before
199 memory accesses. This is faster than outline (in some workloads
200 it gives about x2 boost over outline instrumentation), but
201 make kernel's .text size much bigger.
202 This requires a gcc version of 5.0 or later.
207 bool "Compile the kernel with code coverage for fuzzing"
208 select KERNEL_DEBUG_FS
210 KCOV exposes kernel code coverage information in a form suitable
211 for coverage-guided fuzzing (randomized testing).
213 If RANDOMIZE_BASE is enabled, PC values will not be stable across
214 different machines and across reboots. If you need stable PC values,
215 disable RANDOMIZE_BASE.
217 For more details, see Documentation/kcov.txt.
219 config KERNEL_KCOV_ENABLE_COMPARISONS
220 bool "Enable comparison operands collection by KCOV"
221 depends on KERNEL_KCOV
223 KCOV also exposes operands of every comparison in the instrumented
224 code along with operand sizes and PCs of the comparison instructions.
225 These operands can be used by fuzzing engines to improve the quality
228 config KERNEL_KCOV_INSTRUMENT_ALL
229 bool "Instrument all code by default"
230 depends on KERNEL_KCOV
231 default y if KERNEL_KCOV
233 If you are doing generic system call fuzzing (like e.g. syzkaller),
234 then you will want to instrument the whole kernel and you should
235 say y here. If you are doing more targeted fuzzing (like e.g.
236 filesystem fuzzing with AFL) then you will want to enable coverage
237 for more specific subsets of files, and should say n here.
239 config KERNEL_TASKSTATS
240 bool "Compile the kernel with task resource/io statistics and accounting"
243 Enable the collection and publishing of task/io statistics and
244 accounting. Enable this option to enable i/o monitoring in system
249 config KERNEL_TASK_DELAY_ACCT
252 config KERNEL_TASK_IO_ACCOUNTING
255 config KERNEL_TASK_XACCT
260 config KERNEL_KALLSYMS
261 bool "Compile the kernel with symbol table information"
262 default y if !SMALL_FLASH
264 This will give you more information in stack traces from kernel oopses.
267 bool "Compile the kernel with tracing support"
268 depends on !TARGET_uml
271 config KERNEL_FTRACE_SYSCALLS
272 bool "Trace system calls"
273 depends on KERNEL_FTRACE
276 config KERNEL_ENABLE_DEFAULT_TRACERS
277 bool "Trace process context switches and events"
278 depends on KERNEL_FTRACE
281 config KERNEL_FUNCTION_TRACER
282 bool "Function tracer"
283 depends on KERNEL_FTRACE
286 config KERNEL_FUNCTION_GRAPH_TRACER
287 bool "Function graph tracer"
288 depends on KERNEL_FUNCTION_TRACER
291 config KERNEL_DYNAMIC_FTRACE
292 bool "Enable/disable function tracing dynamically"
293 depends on KERNEL_FUNCTION_TRACER
296 config KERNEL_FUNCTION_PROFILER
297 bool "Function profiler"
298 depends on KERNEL_FUNCTION_TRACER
301 config KERNEL_IRQSOFF_TRACER
302 bool "Interrupts-off Latency Tracer"
303 depends on KERNEL_FTRACE
305 This option measures the time spent in irqs-off critical
306 sections, with microsecond accuracy.
308 The default measurement method is a maximum search, which is
309 disabled by default and can be runtime (re-)started
312 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
314 (Note that kernel size and overhead increase with this option
315 enabled. This option and the preempt-off timing option can be
316 used together or separately.)
318 config KERNEL_PREEMPT_TRACER
319 bool "Preemption-off Latency Tracer"
320 depends on KERNEL_FTRACE
322 This option measures the time spent in preemption-off critical
323 sections, with microsecond accuracy.
325 The default measurement method is a maximum search, which is
326 disabled by default and can be runtime (re-)started
329 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
331 (Note that kernel size and overhead increase with this option
332 enabled. This option and the irqs-off timing option can be
333 used together or separately.)
335 config KERNEL_DEBUG_KERNEL
339 config KERNEL_DEBUG_INFO
340 bool "Compile the kernel with debug information"
341 default y if !SMALL_FLASH
342 select KERNEL_DEBUG_KERNEL
344 This will compile your kernel and modules with debug information.
346 config KERNEL_DEBUG_LL_UART_NONE
351 config KERNEL_DEBUG_LL
355 select KERNEL_DEBUG_LL_UART_NONE
357 ARM low level debugging.
359 config KERNEL_DYNAMIC_DEBUG
360 bool "Compile the kernel with dynamic printk"
361 select KERNEL_DEBUG_FS
364 Compiles debug level messages into the kernel, which would not
365 otherwise be available at runtime. These messages can then be
366 enabled/disabled based on various levels of scope - per source file,
367 function, module, format string, and line number. This mechanism
368 implicitly compiles in all pr_debug() and dev_dbg() calls, which
369 enlarges the kernel text size by about 2%.
371 config KERNEL_EARLY_PRINTK
372 bool "Compile the kernel with early printk"
373 default y if TARGET_bcm53xx
376 select KERNEL_DEBUG_KERNEL
377 select KERNEL_DEBUG_LL if arm
379 Compile the kernel with early printk support. This is only useful for
380 debugging purposes to send messages over the serial console in early boot.
381 Enable this to debug early boot problems.
383 config KERNEL_KPROBES
384 bool "Compile the kernel with kprobes support"
387 select KERNEL_PERF_EVENTS
389 Compiles the kernel with KPROBES support, which allows you to trap
390 at almost any kernel address and execute a callback function.
391 register_kprobe() establishes a probepoint and specifies the
392 callback. Kprobes is useful for kernel debugging, non-intrusive
393 instrumentation and testing.
394 If in doubt, say "N".
396 config KERNEL_KPROBE_EVENTS
398 default y if KERNEL_KPROBES
401 bool "Compile the kernel with asynchronous IO support"
402 default y if !SMALL_FLASH
404 config KERNEL_IO_URING
405 bool "Compile the kernel with io_uring support"
406 default y if !SMALL_FLASH
408 config KERNEL_FHANDLE
409 bool "Compile the kernel with support for fhandle syscalls"
410 default y if !SMALL_FLASH
412 config KERNEL_FANOTIFY
413 bool "Compile the kernel with modern file notification support"
414 default y if !SMALL_FLASH
416 config KERNEL_BLK_DEV_BSG
417 bool "Compile the kernel with SCSI generic v4 support for any block device"
420 config KERNEL_TRANSPARENT_HUGEPAGE
424 prompt "Transparent Hugepage Support sysfs defaults"
425 depends on KERNEL_TRANSPARENT_HUGEPAGE
426 default KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
428 config KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
431 config KERNEL_TRANSPARENT_HUGEPAGE_MADVISE
435 config KERNEL_HUGETLBFS
438 config KERNEL_HUGETLB_PAGE
439 bool "Compile the kernel with HugeTLB support"
440 select KERNEL_TRANSPARENT_HUGEPAGE
441 select KERNEL_HUGETLBFS
444 config KERNEL_MAGIC_SYSRQ
445 bool "Compile the kernel with SysRq support"
448 config KERNEL_DEBUG_PINCTRL
449 bool "Compile the kernel with pinctrl debugging"
450 select KERNEL_DEBUG_KERNEL
452 config KERNEL_DEBUG_GPIO
453 bool "Compile the kernel with gpio debugging"
454 select KERNEL_DEBUG_KERNEL
456 config KERNEL_COREDUMP
459 config KERNEL_ELF_CORE
460 bool "Enable process core dump support"
461 select KERNEL_COREDUMP
462 default y if !SMALL_FLASH
464 config KERNEL_PROVE_LOCKING
465 bool "Enable kernel lock checking"
466 select KERNEL_DEBUG_KERNEL
469 config KERNEL_SOFTLOCKUP_DETECTOR
470 bool "Compile the kernel with detect Soft Lockups"
471 depends on KERNEL_DEBUG_KERNEL
473 Say Y here to enable the kernel to act as a watchdog to detect
476 Softlockups are bugs that cause the kernel to loop in kernel
477 mode for more than 20 seconds, without giving other tasks a
478 chance to run. The current stack trace is displayed upon
479 detection and the system will stay locked up.
481 config KERNEL_DETECT_HUNG_TASK
482 bool "Compile the kernel with detect Hung Tasks"
483 depends on KERNEL_DEBUG_KERNEL
484 default KERNEL_SOFTLOCKUP_DETECTOR
486 Say Y here to enable the kernel to detect "hung tasks",
487 which are bugs that cause the task to be stuck in
488 uninterruptible "D" state indefinitely.
490 When a hung task is detected, the kernel will print the
491 current stack trace (which you should report), but the
492 task will stay in uninterruptible state. If lockdep is
493 enabled then all held locks will also be reported. This
494 feature has negligible overhead.
496 config KERNEL_WQ_WATCHDOG
497 bool "Compile the kernel with detect Workqueue Stalls"
498 depends on KERNEL_DEBUG_KERNEL
500 Say Y here to enable stall detection on workqueues. If a
501 worker pool doesn't make forward progress on a pending work
502 item for over a given amount of time, 30s by default, a
503 warning message is printed along with dump of workqueue
504 state. This can be configured through kernel parameter
505 "workqueue.watchdog_thresh" and its sysfs counterpart.
507 config KERNEL_DEBUG_ATOMIC_SLEEP
508 bool "Compile the kernel with sleep inside atomic section checking"
509 depends on KERNEL_DEBUG_KERNEL
511 If you say Y here, various routines which may sleep will become very
512 noisy if they are called inside atomic sections: when a spinlock is
513 held, inside an rcu read side critical section, inside preempt disabled
514 sections, inside an interrupt, etc...
516 config KERNEL_DEBUG_VM
517 bool "Compile the kernel with debug VM"
518 depends on KERNEL_DEBUG_KERNEL
520 Enable this to turn on extended checks in the virtual-memory system
521 that may impact performance.
525 config KERNEL_PRINTK_TIME
526 bool "Enable printk timestamps"
529 config KERNEL_SLUB_DEBUG
532 config KERNEL_SLUB_DEBUG_ON
535 config KERNEL_SLABINFO
536 select KERNEL_SLUB_DEBUG
537 select KERNEL_SLUB_DEBUG_ON
538 bool "Enable /proc slab debug info"
540 config KERNEL_PROC_PAGE_MONITOR
541 bool "Enable /proc page monitoring"
547 bool "Enable kexec support"
549 config KERNEL_PROC_VMCORE
552 config KERNEL_PROC_KCORE
555 config KERNEL_CRASH_DUMP
556 depends on i386 || x86_64 || arm || armeb
558 select KERNEL_PROC_VMCORE
559 select KERNEL_PROC_KCORE
560 bool "Enable support for kexec crashdump"
564 bool "Enable rfkill support"
565 default RFKILL_SUPPORT
568 bool "Enable sparse check during kernel build"
571 config KERNEL_DEVTMPFS
572 bool "Compile the kernel with device tmpfs enabled"
575 devtmpfs is a simple, kernel-managed /dev filesystem. The kernel creates
576 devices nodes for all registered devices to simplify boot, but leaves more
577 complex tasks to userspace (e.g. udev).
581 config KERNEL_DEVTMPFS_MOUNT
582 bool "Automatically mount devtmpfs after root filesystem is mounted"
588 bool "Enable kernel access key retention support"
591 config KERNEL_PERSISTENT_KEYRINGS
592 bool "Enable kernel persistent keyrings"
593 depends on KERNEL_KEYS
596 config KERNEL_KEYS_REQUEST_CACHE
597 bool "Enable temporary caching of the last request_key() result"
598 depends on KERNEL_KEYS
601 config KERNEL_BIG_KEYS
602 bool "Enable large payload keys on kernel keyrings"
603 depends on KERNEL_KEYS
607 # CGROUP support symbols
610 config KERNEL_CGROUPS
611 bool "Enable kernel cgroups"
612 default y if !SMALL_FLASH
616 config KERNEL_CGROUP_DEBUG
617 bool "Example debug cgroup subsystem"
620 This option enables a simple cgroup subsystem that
621 exports useful debugging information about the cgroups
624 config KERNEL_FREEZER
627 config KERNEL_CGROUP_FREEZER
628 bool "legacy Freezer cgroup subsystem"
630 select KERNEL_FREEZER
632 Provides a way to freeze and unfreeze all tasks in a
634 (legacy cgroup1-only controller, in cgroup2 freezer
635 is integrated in the Memory controller)
637 config KERNEL_CGROUP_DEVICE
638 bool "legacy Device controller for cgroups"
641 Provides a cgroup implementing whitelists for devices which
642 a process in the cgroup can mknod or open.
643 (legacy cgroup1-only controller)
645 config KERNEL_CGROUP_HUGETLB
646 bool "HugeTLB controller"
648 select KERNEL_HUGETLB_PAGE
650 config KERNEL_CGROUP_PIDS
651 bool "PIDs cgroup subsystem"
654 Provides enforcement of process number limits in the scope of a
657 config KERNEL_CGROUP_RDMA
658 bool "RDMA controller for cgroups"
661 config KERNEL_CGROUP_BPF
662 bool "Support for eBPF programs attached to cgroups"
665 config KERNEL_CPUSETS
666 bool "Cpuset support"
669 This option will let you create and manage CPUSETs which
670 allow dynamically partitioning a system into sets of CPUs and
671 Memory Nodes and assigning tasks to run only within those sets.
672 This is primarily useful on large SMP or NUMA systems.
674 config KERNEL_PROC_PID_CPUSET
675 bool "Include legacy /proc/<pid>/cpuset file"
677 depends on KERNEL_CPUSETS
679 config KERNEL_CGROUP_CPUACCT
680 bool "Simple CPU accounting cgroup subsystem"
683 Provides a simple Resource Controller for monitoring the
684 total CPU consumed by the tasks in a cgroup.
686 config KERNEL_RESOURCE_COUNTERS
687 bool "Resource counters"
690 This option enables controller independent resource accounting
691 infrastructure that works with cgroups.
693 config KERNEL_MM_OWNER
695 default y if KERNEL_MEMCG
698 bool "Memory Resource Controller for Control Groups"
700 select KERNEL_FREEZER
701 depends on KERNEL_RESOURCE_COUNTERS || !LINUX_3_18
703 Provides a memory resource controller that manages both anonymous
704 memory and page cache. (See Documentation/cgroups/memory.txt)
706 Note that setting this option increases fixed memory overhead
707 associated with each page of memory in the system. By this,
708 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
709 usage tracking struct at boot. Total amount of this is printed out
712 Only enable when you're ok with these tradeoffs and really
713 sure you need the memory resource controller. Even when you enable
714 this, you can set "cgroup_disable=memory" at your boot option to
715 disable memory resource controller and you can avoid overheads
716 (but lose benefits of memory resource controller).
718 This config option also selects MM_OWNER config option, which
719 could in turn add some fork/exit overhead.
721 config KERNEL_MEMCG_SWAP
722 bool "Memory Resource Controller Swap Extension"
724 depends on KERNEL_MEMCG
726 Add swap management feature to memory resource controller. When you
727 enable this, you can limit mem+swap usage per cgroup. In other words,
728 when you disable this, memory resource controller has no cares to
729 usage of swap...a process can exhaust all of the swap. This extension
730 is useful when you want to avoid exhaustion swap but this itself
731 adds more overheads and consumes memory for remembering information.
732 Especially if you use 32bit system or small memory system, please
733 be careful about enabling this. When memory resource controller
734 is disabled by boot option, this will be automatically disabled and
735 there will be no overhead from this. Even when you set this config=y,
736 if boot option "swapaccount=0" is set, swap will not be accounted.
737 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
738 size is 4096bytes, 512k per 1Gbytes of swap.
740 config KERNEL_MEMCG_SWAP_ENABLED
741 bool "Memory Resource Controller Swap Extension enabled by default"
743 depends on KERNEL_MEMCG_SWAP
745 Memory Resource Controller Swap Extension comes with its price in
746 a bigger memory consumption. General purpose distribution kernels
747 which want to enable the feature but keep it disabled by default
748 and let the user enable it by swapaccount boot command line
749 parameter should have this option unselected.
751 Those who want to have the feature enabled by default should
752 select this option (if, for some reason, they need to disable it,
753 then swapaccount=0 does the trick).
756 config KERNEL_MEMCG_KMEM
757 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
759 depends on KERNEL_MEMCG
761 The Kernel Memory extension for Memory Resource Controller can limit
762 the amount of memory used by kernel objects in the system. Those are
763 fundamentally different from the entities handled by the standard
764 Memory Controller, which are page-based, and can be swapped. Users of
765 the kmem extension can use it to guarantee that no group of processes
766 will ever exhaust kernel resources alone.
768 config KERNEL_CGROUP_PERF
769 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
770 select KERNEL_PERF_EVENTS
773 This option extends the per-cpu mode to restrict monitoring to
774 threads which belong to the cgroup specified and run on the
777 menuconfig KERNEL_CGROUP_SCHED
778 bool "Group CPU scheduler"
781 This feature lets CPU scheduler recognize task groups and control CPU
782 bandwidth allocation to such task groups. It uses cgroups to group
785 if KERNEL_CGROUP_SCHED
787 config KERNEL_FAIR_GROUP_SCHED
788 bool "Group scheduling for SCHED_OTHER"
791 config KERNEL_CFS_BANDWIDTH
792 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
794 depends on KERNEL_FAIR_GROUP_SCHED
796 This option allows users to define CPU bandwidth rates (limits) for
797 tasks running within the fair group scheduler. Groups with no limit
798 set are considered to be unconstrained and will run with no
800 See tip/Documentation/scheduler/sched-bwc.txt for more information.
802 config KERNEL_RT_GROUP_SCHED
803 bool "Group scheduling for SCHED_RR/FIFO"
806 This feature lets you explicitly allocate real CPU bandwidth
807 to task groups. If enabled, it will also make it impossible to
808 schedule realtime tasks for non-root users until you allocate
809 realtime bandwidth for them.
813 config KERNEL_BLK_CGROUP
814 bool "Block IO controller"
817 Generic block IO controller cgroup interface. This is the common
818 cgroup interface which should be used by various IO controlling
821 Currently, CFQ IO scheduler uses it to recognize task groups and
822 control disk bandwidth allocation (proportional time slice allocation)
823 to such task groups. It is also used by bio throttling logic in
824 block layer to implement upper limit in IO rates on a device.
826 This option only enables generic Block IO controller infrastructure.
827 One needs to also enable actual IO controlling logic/policy. For
828 enabling proportional weight division of disk bandwidth in CFQ, set
829 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
830 CONFIG_BLK_DEV_THROTTLING=y.
834 config KERNEL_CFQ_GROUP_IOSCHED
835 bool "Proportional weight of disk bandwidth in CFQ"
837 config KERNEL_BLK_DEV_THROTTLING
838 bool "Enable throttling policy"
841 config KERNEL_BLK_DEV_THROTTLING_LOW
842 bool "Block throttling .low limit interface support (EXPERIMENTAL)"
843 depends on KERNEL_BLK_DEV_THROTTLING
846 config KERNEL_DEBUG_BLK_CGROUP
847 bool "Enable Block IO controller debugging"
849 depends on KERNEL_BLK_CGROUP
851 Enable some debugging help. Currently it exports additional stat
852 files in a cgroup which can be useful for debugging.
854 config KERNEL_NET_CLS_CGROUP
855 bool "legacy Control Group Classifier"
858 config KERNEL_CGROUP_NET_CLASSID
859 bool "legacy Network classid cgroup"
862 config KERNEL_CGROUP_NET_PRIO
863 bool "legacy Network priority cgroup"
869 # Namespace support symbols
872 config KERNEL_NAMESPACES
873 bool "Enable kernel namespaces"
874 default y if !SMALL_FLASH
882 In this namespace, tasks see different info provided
883 with the uname() system call.
889 In this namespace, tasks work with IPC ids which correspond to
890 different IPC objects in different namespaces.
892 config KERNEL_USER_NS
893 bool "User namespace (EXPERIMENTAL)"
896 This allows containers, i.e. vservers, to use user namespaces
897 to provide different user info for different servers.
900 bool "PID Namespaces"
903 Support process id namespaces. This allows having multiple
904 processes with the same pid as long as they are in different
905 pid namespaces. This is a building block of containers.
908 bool "Network namespace"
911 Allow user space to create what appear to be multiple instances
912 of the network stack.
916 config KERNEL_DEVPTS_MULTIPLE_INSTANCES
917 bool "Support multiple instances of devpts"
918 default y if !SMALL_FLASH
920 Enable support for multiple instances of devpts filesystem.
921 If you want to have isolated PTY namespaces (eg: in containers),
922 say Y here. Otherwise, say N. If enabled, each mount of devpts
923 filesystem with the '-o newinstance' option will create an
924 independent PTY namespace.
926 config KERNEL_POSIX_MQUEUE
927 bool "POSIX Message Queues"
928 default y if !SMALL_FLASH
930 POSIX variant of message queues is a part of IPC. In POSIX message
931 queues every message has a priority which decides about succession
932 of receiving it by a process. If you want to compile and run
933 programs written e.g. for Solaris with use of its POSIX message
934 queues (functions mq_*) say Y here.
936 POSIX message queues are visible as a filesystem called 'mqueue'
937 and can be mounted somewhere if you want to do filesystem
938 operations on message queues.
941 config KERNEL_SECCOMP_FILTER
943 default y if !SMALL_FLASH
945 config KERNEL_SECCOMP
946 bool "Enable seccomp support"
947 depends on !(TARGET_uml)
948 select KERNEL_SECCOMP_FILTER
949 default y if !SMALL_FLASH
951 Build kernel with support for seccomp.
957 config KERNEL_IP_MROUTE
958 bool "Enable IPv4 multicast routing"
961 Multicast routing requires a multicast routing daemon in
962 addition to kernel support.
973 config KERNEL_IPV6_MULTIPLE_TABLES
976 config KERNEL_IPV6_SUBTREES
979 config KERNEL_IPV6_MROUTE
980 bool "Enable IPv6 multicast routing"
983 Multicast routing requires a multicast routing daemon in
984 addition to kernel support.
986 config KERNEL_IPV6_PIMSM_V2
989 config KERNEL_IPV6_SEG6_LWTUNNEL
990 bool "Enable support for lightweight tunnels"
991 default y if !SMALL_FLASH
993 Using lwtunnel (needed for IPv6 segment routing) requires ip-full package.
995 config KERNEL_LWTUNNEL_BPF
1001 # NFS related symbols
1003 config KERNEL_IP_PNP
1004 bool "Compile the kernel with rootfs on NFS"
1006 If you want to make your kernel boot off a NFS server as root
1007 filesystem, select Y here.
1011 config KERNEL_IP_PNP_DHCP
1014 config KERNEL_IP_PNP_BOOTP
1017 config KERNEL_IP_PNP_RARP
1020 config KERNEL_NFS_FS
1023 config KERNEL_NFS_V2
1026 config KERNEL_NFS_V3
1029 config KERNEL_ROOT_NFS
1034 menu "Filesystem ACL and attr support options"
1035 config USE_FS_ACL_ATTR
1036 bool "Use filesystem ACL and attr support by default"
1039 Make using ACLs (e.g. POSIX ACL, NFSv4 ACL) the default
1040 for kernel and packages, except tmpfs, flash filesystems,
1041 and old NFS. Also enable userspace extended attribute support
1042 by default. (OpenWrt already has an expection it will be
1043 present in the kernel).
1045 config KERNEL_FS_POSIX_ACL
1046 bool "Enable POSIX ACL support"
1047 default y if USE_FS_ACL_ATTR
1049 config KERNEL_BTRFS_FS_POSIX_ACL
1050 bool "Enable POSIX ACL for BtrFS Filesystems"
1051 select KERNEL_FS_POSIX_ACL
1052 default y if USE_FS_ACL_ATTR
1054 config KERNEL_EXT4_FS_POSIX_ACL
1055 bool "Enable POSIX ACL for Ext4 Filesystems"
1056 select KERNEL_FS_POSIX_ACL
1057 default y if USE_FS_ACL_ATTR
1059 config KERNEL_F2FS_FS_POSIX_ACL
1060 bool "Enable POSIX ACL for F2FS Filesystems"
1061 select KERNEL_FS_POSIX_ACL
1064 config KERNEL_JFFS2_FS_POSIX_ACL
1065 bool "Enable POSIX ACL for JFFS2 Filesystems"
1066 select KERNEL_FS_POSIX_ACL
1069 config KERNEL_TMPFS_POSIX_ACL
1070 bool "Enable POSIX ACL for TMPFS Filesystems"
1071 select KERNEL_FS_POSIX_ACL
1074 config KERNEL_CIFS_ACL
1075 bool "Enable CIFS ACLs"
1076 select KERNEL_FS_POSIX_ACL
1077 default y if USE_FS_ACL_ATTR
1079 config KERNEL_HFS_FS_POSIX_ACL
1080 bool "Enable POSIX ACL for HFS Filesystems"
1081 select KERNEL_FS_POSIX_ACL
1082 default y if USE_FS_ACL_ATTR
1084 config KERNEL_HFSPLUS_FS_POSIX_ACL
1085 bool "Enable POSIX ACL for HFS+ Filesystems"
1086 select KERNEL_FS_POSIX_ACL
1087 default y if USE_FS_ACL_ATTR
1089 config KERNEL_NFS_ACL_SUPPORT
1090 bool "Enable ACLs for NFS"
1091 default y if USE_FS_ACL_ATTR
1093 config KERNEL_NFS_V3_ACL_SUPPORT
1094 bool "Enable ACLs for NFSv3"
1097 config KERNEL_NFSD_V2_ACL_SUPPORT
1098 bool "Enable ACLs for NFSDv2"
1101 config KERNEL_NFSD_V3_ACL_SUPPORT
1102 bool "Enable ACLs for NFSDv3"
1105 config KERNEL_REISER_FS_POSIX_ACL
1106 bool "Enable POSIX ACLs for ReiserFS"
1107 select KERNEL_FS_POSIX_ACL
1108 default y if USE_FS_ACL_ATTR
1110 config KERNEL_XFS_POSIX_ACL
1111 bool "Enable POSIX ACLs for XFS"
1112 select KERNEL_FS_POSIX_ACL
1113 default y if USE_FS_ACL_ATTR
1115 config KERNEL_JFS_POSIX_ACL
1116 bool "Enable POSIX ACLs for JFS"
1117 select KERNEL_FS_POSIX_ACL
1118 default y if USE_FS_ACL_ATTR
1122 config KERNEL_DEVMEM
1123 bool "/dev/mem virtual device support"
1125 Say Y here if you want to support the /dev/mem device.
1126 The /dev/mem device is used to access areas of physical
1129 config KERNEL_DEVKMEM
1130 bool "/dev/kmem virtual device support"
1132 Say Y here if you want to support the /dev/kmem device. The
1133 /dev/kmem device is rarely used, but can be used for certain
1134 kind of kernel debugging operations.
1136 config KERNEL_SQUASHFS_FRAGMENT_CACHE_SIZE
1137 int "Number of squashfs fragments cached"
1138 default 2 if (SMALL_FLASH && !LOW_MEMORY_FOOTPRINT)
1141 config KERNEL_SQUASHFS_XATTR
1142 bool "Squashfs XATTR support"
1145 # compile optimization setting
1148 prompt "Compiler optimization level"
1149 default KERNEL_CC_OPTIMIZE_FOR_SIZE if SMALL_FLASH
1151 config KERNEL_CC_OPTIMIZE_FOR_PERFORMANCE
1152 bool "Optimize for performance"
1154 This is the default optimization level for the kernel, building
1155 with the "-O2" compiler flag for best performance and most
1156 helpful compile-time warnings.
1158 config KERNEL_CC_OPTIMIZE_FOR_SIZE
1159 bool "Optimize for size"
1161 Enabling this option will pass "-Os" instead of "-O2" to
1162 your compiler resulting in a smaller kernel.
1167 bool "Auditing support"
1169 config KERNEL_SECURITY
1170 bool "Enable different security models"
1172 config KERNEL_SECURITY_NETWORK
1173 bool "Socket and Networking Security Hooks"
1174 select KERNEL_SECURITY
1176 config KERNEL_SECURITY_SELINUX
1177 bool "NSA SELinux Support"
1178 select KERNEL_SECURITY_NETWORK
1181 config KERNEL_SECURITY_SELINUX_BOOTPARAM
1182 bool "NSA SELinux boot parameter"
1183 depends on KERNEL_SECURITY_SELINUX
1186 config KERNEL_SECURITY_SELINUX_DISABLE
1187 bool "NSA SELinux runtime disable"
1188 depends on KERNEL_SECURITY_SELINUX
1190 config KERNEL_SECURITY_SELINUX_DEVELOP
1191 bool "NSA SELinux Development Support"
1192 depends on KERNEL_SECURITY_SELINUX
1195 config KERNEL_SECURITY_SELINUX_SIDTAB_HASH_BITS
1197 depends on KERNEL_SECURITY_SELINUX
1200 config KERNEL_SECURITY_SELINUX_SID2STR_CACHE_SIZE
1202 depends on KERNEL_SECURITY_SELINUX
1207 default "lockdown,yama,loadpin,safesetid,integrity,selinux"
1208 depends on KERNEL_SECURITY_SELINUX
1210 config KERNEL_EXT4_FS_SECURITY
1211 bool "Ext4 Security Labels"
1213 config KERNEL_F2FS_FS_SECURITY
1214 bool "F2FS Security Labels"
1216 config KERNEL_UBIFS_FS_SECURITY
1217 bool "UBIFS Security Labels"
1219 config KERNEL_JFFS2_FS_SECURITY
1220 bool "JFFS2 Security Labels"