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_NULL
118 bool "Enable checking of null pointers"
119 depends on KERNEL_UBSAN
121 This option enables detection of memory accesses via a
125 bool "Compile the kernel with KASan: runtime memory debugger"
126 select KERNEL_SLUB_DEBUG
127 depends on (x86_64 || aarch64)
129 Enables kernel address sanitizer - runtime memory debugger,
130 designed to find out-of-bounds accesses and use-after-free bugs.
131 This is strictly a debugging feature and it requires a gcc version
132 of 4.9.2 or later. Detection of out of bounds accesses to stack or
133 global variables requires gcc 5.0 or later.
134 This feature consumes about 1/8 of available memory and brings about
135 ~x3 performance slowdown.
136 For better error detection enable CONFIG_STACKTRACE.
137 Currently CONFIG_KASAN doesn't work with CONFIG_DEBUG_SLAB
138 (the resulting kernel does not boot).
140 config KERNEL_KASAN_EXTRA
141 bool "KAsan: extra checks"
142 depends on KERNEL_KASAN && KERNEL_DEBUG_KERNEL
144 This enables further checks in the kernel address sanitizer, for now
145 it only includes the address-use-after-scope check that can lead
146 to excessive kernel stack usage, frame size warnings and longer
148 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 has more
152 prompt "Instrumentation type"
153 depends on KERNEL_KASAN
154 default KERNEL_KASAN_OUTLINE
156 config KERNEL_KASAN_OUTLINE
157 bool "Outline instrumentation"
159 Before every memory access compiler insert function call
160 __asan_load*/__asan_store*. These functions performs check
161 of shadow memory. This is slower than inline instrumentation,
162 however it doesn't bloat size of kernel's .text section so
165 config KERNEL_KASAN_INLINE
166 bool "Inline instrumentation"
168 Compiler directly inserts code checking shadow memory before
169 memory accesses. This is faster than outline (in some workloads
170 it gives about x2 boost over outline instrumentation), but
171 make kernel's .text size much bigger.
172 This requires a gcc version of 5.0 or later.
177 bool "Compile the kernel with code coverage for fuzzing"
178 select KERNEL_DEBUG_FS
180 KCOV exposes kernel code coverage information in a form suitable
181 for coverage-guided fuzzing (randomized testing).
183 If RANDOMIZE_BASE is enabled, PC values will not be stable across
184 different machines and across reboots. If you need stable PC values,
185 disable RANDOMIZE_BASE.
187 For more details, see Documentation/kcov.txt.
189 config KERNEL_KCOV_ENABLE_COMPARISONS
190 bool "Enable comparison operands collection by KCOV"
191 depends on KERNEL_KCOV
193 KCOV also exposes operands of every comparison in the instrumented
194 code along with operand sizes and PCs of the comparison instructions.
195 These operands can be used by fuzzing engines to improve the quality
198 config KERNEL_KCOV_INSTRUMENT_ALL
199 bool "Instrument all code by default"
200 depends on KERNEL_KCOV
201 default y if KERNEL_KCOV
203 If you are doing generic system call fuzzing (like e.g. syzkaller),
204 then you will want to instrument the whole kernel and you should
205 say y here. If you are doing more targeted fuzzing (like e.g.
206 filesystem fuzzing with AFL) then you will want to enable coverage
207 for more specific subsets of files, and should say n here.
209 config KERNEL_TASKSTATS
210 bool "Compile the kernel with task resource/io statistics and accounting"
213 Enable the collection and publishing of task/io statistics and
214 accounting. Enable this option to enable i/o monitoring in system
219 config KERNEL_TASK_DELAY_ACCT
222 config KERNEL_TASK_IO_ACCOUNTING
225 config KERNEL_TASK_XACCT
230 config KERNEL_KALLSYMS
231 bool "Compile the kernel with symbol table information"
232 default y if !SMALL_FLASH
234 This will give you more information in stack traces from kernel oopses.
237 bool "Compile the kernel with tracing support"
238 depends on !TARGET_uml
241 config KERNEL_FTRACE_SYSCALLS
242 bool "Trace system calls"
243 depends on KERNEL_FTRACE
246 config KERNEL_ENABLE_DEFAULT_TRACERS
247 bool "Trace process context switches and events"
248 depends on KERNEL_FTRACE
251 config KERNEL_FUNCTION_TRACER
252 bool "Function tracer"
253 depends on KERNEL_FTRACE
256 config KERNEL_FUNCTION_GRAPH_TRACER
257 bool "Function graph tracer"
258 depends on KERNEL_FUNCTION_TRACER
261 config KERNEL_DYNAMIC_FTRACE
262 bool "Enable/disable function tracing dynamically"
263 depends on KERNEL_FUNCTION_TRACER
266 config KERNEL_FUNCTION_PROFILER
267 bool "Function profiler"
268 depends on KERNEL_FUNCTION_TRACER
271 config KERNEL_IRQSOFF_TRACER
272 bool "Interrupts-off Latency Tracer"
273 depends on KERNEL_FTRACE
275 This option measures the time spent in irqs-off critical
276 sections, with microsecond accuracy.
278 The default measurement method is a maximum search, which is
279 disabled by default and can be runtime (re-)started
282 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
284 (Note that kernel size and overhead increase with this option
285 enabled. This option and the preempt-off timing option can be
286 used together or separately.)
288 config KERNEL_PREEMPT_TRACER
289 bool "Preemption-off Latency Tracer"
290 depends on KERNEL_FTRACE
292 This option measures the time spent in preemption-off critical
293 sections, with microsecond accuracy.
295 The default measurement method is a maximum search, which is
296 disabled by default and can be runtime (re-)started
299 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
301 (Note that kernel size and overhead increase with this option
302 enabled. This option and the irqs-off timing option can be
303 used together or separately.)
305 config KERNEL_DEBUG_KERNEL
309 config KERNEL_DEBUG_INFO
310 bool "Compile the kernel with debug information"
311 default y if !SMALL_FLASH
312 select KERNEL_DEBUG_KERNEL
314 This will compile your kernel and modules with debug information.
316 config KERNEL_DEBUG_LL_UART_NONE
321 config KERNEL_DEBUG_LL
325 select KERNEL_DEBUG_LL_UART_NONE
327 ARM low level debugging.
329 config KERNEL_DYNAMIC_DEBUG
330 bool "Compile the kernel with dynamic printk"
331 select KERNEL_DEBUG_FS
334 Compiles debug level messages into the kernel, which would not
335 otherwise be available at runtime. These messages can then be
336 enabled/disabled based on various levels of scope - per source file,
337 function, module, format string, and line number. This mechanism
338 implicitly compiles in all pr_debug() and dev_dbg() calls, which
339 enlarges the kernel text size by about 2%.
341 config KERNEL_EARLY_PRINTK
342 bool "Compile the kernel with early printk"
343 default y if TARGET_bcm53xx
346 select KERNEL_DEBUG_KERNEL
347 select KERNEL_DEBUG_LL if arm
349 Compile the kernel with early printk support. This is only useful for
350 debugging purposes to send messages over the serial console in early boot.
351 Enable this to debug early boot problems.
353 config KERNEL_KPROBES
354 bool "Compile the kernel with kprobes support"
357 select KERNEL_PERF_EVENTS
359 Compiles the kernel with KPROBES support, which allows you to trap
360 at almost any kernel address and execute a callback function.
361 register_kprobe() establishes a probepoint and specifies the
362 callback. Kprobes is useful for kernel debugging, non-intrusive
363 instrumentation and testing.
364 If in doubt, say "N".
366 config KERNEL_KPROBE_EVENTS
368 default y if KERNEL_KPROBES
371 bool "Compile the kernel with asynchronous IO support"
372 default y if !SMALL_FLASH
374 config KERNEL_IO_URING
375 bool "Compile the kernel with io_uring support"
376 default y if !SMALL_FLASH
378 config KERNEL_FHANDLE
379 bool "Compile the kernel with support for fhandle syscalls"
380 default y if !SMALL_FLASH
382 config KERNEL_FANOTIFY
383 bool "Compile the kernel with modern file notification support"
384 default y if !SMALL_FLASH
386 config KERNEL_BLK_DEV_BSG
387 bool "Compile the kernel with SCSI generic v4 support for any block device"
390 config KERNEL_TRANSPARENT_HUGEPAGE
394 prompt "Transparent Hugepage Support sysfs defaults"
395 depends on KERNEL_TRANSPARENT_HUGEPAGE
396 default KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
398 config KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
401 config KERNEL_TRANSPARENT_HUGEPAGE_MADVISE
405 config KERNEL_HUGETLBFS
408 config KERNEL_HUGETLB_PAGE
409 bool "Compile the kernel with HugeTLB support"
410 select KERNEL_TRANSPARENT_HUGEPAGE
411 select KERNEL_HUGETLBFS
414 config KERNEL_MAGIC_SYSRQ
415 bool "Compile the kernel with SysRq support"
418 config KERNEL_DEBUG_PINCTRL
419 bool "Compile the kernel with pinctrl debugging"
420 select KERNEL_DEBUG_KERNEL
422 config KERNEL_DEBUG_GPIO
423 bool "Compile the kernel with gpio debugging"
424 select KERNEL_DEBUG_KERNEL
426 config KERNEL_COREDUMP
429 config KERNEL_ELF_CORE
430 bool "Enable process core dump support"
431 select KERNEL_COREDUMP
432 default y if !SMALL_FLASH
434 config KERNEL_PROVE_LOCKING
435 bool "Enable kernel lock checking"
436 select KERNEL_DEBUG_KERNEL
439 config KERNEL_LOCKUP_DETECTOR
440 bool "Compile the kernel with detect Hard and Soft Lockups"
441 depends on KERNEL_DEBUG_KERNEL
443 Say Y here to enable the kernel to act as a watchdog to detect
444 hard and soft lockups.
446 Softlockups are bugs that cause the kernel to loop in kernel
447 mode for more than 20 seconds, without giving other tasks a
448 chance to run. The current stack trace is displayed upon
449 detection and the system will stay locked up.
451 Hardlockups are bugs that cause the CPU to loop in kernel mode
452 for more than 10 seconds, without letting other interrupts have a
453 chance to run. The current stack trace is displayed upon detection
454 and the system will stay locked up.
456 The overhead should be minimal. A periodic hrtimer runs to
457 generate interrupts and kick the watchdog task every 4 seconds.
458 An NMI is generated every 10 seconds or so to check for hardlockups.
460 The frequency of hrtimer and NMI events and the soft and hard lockup
461 thresholds can be controlled through the sysctl watchdog_thresh.
463 config KERNEL_DETECT_HUNG_TASK
464 bool "Compile the kernel with detect Hung Tasks"
465 depends on KERNEL_DEBUG_KERNEL
466 default KERNEL_LOCKUP_DETECTOR
468 Say Y here to enable the kernel to detect "hung tasks",
469 which are bugs that cause the task to be stuck in
470 uninterruptible "D" state indefinitely.
472 When a hung task is detected, the kernel will print the
473 current stack trace (which you should report), but the
474 task will stay in uninterruptible state. If lockdep is
475 enabled then all held locks will also be reported. This
476 feature has negligible overhead.
478 config KERNEL_WQ_WATCHDOG
479 bool "Compile the kernel with detect Workqueue Stalls"
480 depends on KERNEL_DEBUG_KERNEL
482 Say Y here to enable stall detection on workqueues. If a
483 worker pool doesn't make forward progress on a pending work
484 item for over a given amount of time, 30s by default, a
485 warning message is printed along with dump of workqueue
486 state. This can be configured through kernel parameter
487 "workqueue.watchdog_thresh" and its sysfs counterpart.
489 config KERNEL_DEBUG_ATOMIC_SLEEP
490 bool "Compile the kernel with sleep inside atomic section checking"
491 depends on KERNEL_DEBUG_KERNEL
493 If you say Y here, various routines which may sleep will become very
494 noisy if they are called inside atomic sections: when a spinlock is
495 held, inside an rcu read side critical section, inside preempt disabled
496 sections, inside an interrupt, etc...
498 config KERNEL_DEBUG_VM
499 bool "Compile the kernel with debug VM"
500 depends on KERNEL_DEBUG_KERNEL
502 Enable this to turn on extended checks in the virtual-memory system
503 that may impact performance.
507 config KERNEL_PRINTK_TIME
508 bool "Enable printk timestamps"
511 config KERNEL_SLUB_DEBUG
514 config KERNEL_SLUB_DEBUG_ON
517 config KERNEL_SLABINFO
518 select KERNEL_SLUB_DEBUG
519 select KERNEL_SLUB_DEBUG_ON
520 bool "Enable /proc slab debug info"
522 config KERNEL_PROC_PAGE_MONITOR
523 bool "Enable /proc page monitoring"
529 bool "Enable kexec support"
531 config KERNEL_PROC_VMCORE
534 config KERNEL_PROC_KCORE
537 config KERNEL_CRASH_DUMP
538 depends on i386 || x86_64 || arm || armeb
540 select KERNEL_PROC_VMCORE
541 select KERNEL_PROC_KCORE
542 bool "Enable support for kexec crashdump"
546 bool "Enable rfkill support"
547 default RFKILL_SUPPORT
550 bool "Enable sparse check during kernel build"
553 config KERNEL_DEVTMPFS
554 bool "Compile the kernel with device tmpfs enabled"
557 devtmpfs is a simple, kernel-managed /dev filesystem. The kernel creates
558 devices nodes for all registered devices to simplify boot, but leaves more
559 complex tasks to userspace (e.g. udev).
563 config KERNEL_DEVTMPFS_MOUNT
564 bool "Automatically mount devtmpfs after root filesystem is mounted"
570 bool "Enable kernel access key retention support"
573 config KERNEL_PERSISTENT_KEYRINGS
574 bool "Enable kernel persistent keyrings"
575 depends on KERNEL_KEYS
578 config KERNEL_KEYS_REQUEST_CACHE
579 bool "Enable temporary caching of the last request_key() result"
580 depends on KERNEL_KEYS
583 config KERNEL_BIG_KEYS
584 bool "Enable large payload keys on kernel keyrings"
585 depends on KERNEL_KEYS
589 # CGROUP support symbols
592 config KERNEL_CGROUPS
593 bool "Enable kernel cgroups"
594 default y if !SMALL_FLASH
598 config KERNEL_CGROUP_DEBUG
599 bool "Example debug cgroup subsystem"
602 This option enables a simple cgroup subsystem that
603 exports useful debugging information about the cgroups
606 config KERNEL_FREEZER
609 config KERNEL_CGROUP_FREEZER
610 bool "legacy Freezer cgroup subsystem"
612 select KERNEL_FREEZER
614 Provides a way to freeze and unfreeze all tasks in a
616 (legacy cgroup1-only controller, in cgroup2 freezer
617 is integrated in the Memory controller)
619 config KERNEL_CGROUP_DEVICE
620 bool "legacy Device controller for cgroups"
623 Provides a cgroup implementing whitelists for devices which
624 a process in the cgroup can mknod or open.
625 (legacy cgroup1-only controller)
627 config KERNEL_CGROUP_HUGETLB
628 bool "HugeTLB controller"
630 select KERNEL_HUGETLB_PAGE
632 config KERNEL_CGROUP_PIDS
633 bool "PIDs cgroup subsystem"
636 Provides enforcement of process number limits in the scope of a
639 config KERNEL_CGROUP_RDMA
640 bool "RDMA controller for cgroups"
643 config KERNEL_CGROUP_BPF
644 bool "Support for eBPF programs attached to cgroups"
647 config KERNEL_CPUSETS
648 bool "Cpuset support"
651 This option will let you create and manage CPUSETs which
652 allow dynamically partitioning a system into sets of CPUs and
653 Memory Nodes and assigning tasks to run only within those sets.
654 This is primarily useful on large SMP or NUMA systems.
656 config KERNEL_PROC_PID_CPUSET
657 bool "Include legacy /proc/<pid>/cpuset file"
659 depends on KERNEL_CPUSETS
661 config KERNEL_CGROUP_CPUACCT
662 bool "Simple CPU accounting cgroup subsystem"
665 Provides a simple Resource Controller for monitoring the
666 total CPU consumed by the tasks in a cgroup.
668 config KERNEL_RESOURCE_COUNTERS
669 bool "Resource counters"
672 This option enables controller independent resource accounting
673 infrastructure that works with cgroups.
675 config KERNEL_MM_OWNER
677 default y if KERNEL_MEMCG
680 bool "Memory Resource Controller for Control Groups"
682 select KERNEL_FREEZER
683 depends on KERNEL_RESOURCE_COUNTERS || !LINUX_3_18
685 Provides a memory resource controller that manages both anonymous
686 memory and page cache. (See Documentation/cgroups/memory.txt)
688 Note that setting this option increases fixed memory overhead
689 associated with each page of memory in the system. By this,
690 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
691 usage tracking struct at boot. Total amount of this is printed out
694 Only enable when you're ok with these tradeoffs and really
695 sure you need the memory resource controller. Even when you enable
696 this, you can set "cgroup_disable=memory" at your boot option to
697 disable memory resource controller and you can avoid overheads
698 (but lose benefits of memory resource controller).
700 This config option also selects MM_OWNER config option, which
701 could in turn add some fork/exit overhead.
703 config KERNEL_MEMCG_SWAP
704 bool "Memory Resource Controller Swap Extension"
706 depends on KERNEL_MEMCG
708 Add swap management feature to memory resource controller. When you
709 enable this, you can limit mem+swap usage per cgroup. In other words,
710 when you disable this, memory resource controller has no cares to
711 usage of swap...a process can exhaust all of the swap. This extension
712 is useful when you want to avoid exhaustion swap but this itself
713 adds more overheads and consumes memory for remembering information.
714 Especially if you use 32bit system or small memory system, please
715 be careful about enabling this. When memory resource controller
716 is disabled by boot option, this will be automatically disabled and
717 there will be no overhead from this. Even when you set this config=y,
718 if boot option "swapaccount=0" is set, swap will not be accounted.
719 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
720 size is 4096bytes, 512k per 1Gbytes of swap.
722 config KERNEL_MEMCG_SWAP_ENABLED
723 bool "Memory Resource Controller Swap Extension enabled by default"
725 depends on KERNEL_MEMCG_SWAP
727 Memory Resource Controller Swap Extension comes with its price in
728 a bigger memory consumption. General purpose distribution kernels
729 which want to enable the feature but keep it disabled by default
730 and let the user enable it by swapaccount boot command line
731 parameter should have this option unselected.
733 Those who want to have the feature enabled by default should
734 select this option (if, for some reason, they need to disable it,
735 then swapaccount=0 does the trick).
738 config KERNEL_MEMCG_KMEM
739 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
741 depends on KERNEL_MEMCG
743 The Kernel Memory extension for Memory Resource Controller can limit
744 the amount of memory used by kernel objects in the system. Those are
745 fundamentally different from the entities handled by the standard
746 Memory Controller, which are page-based, and can be swapped. Users of
747 the kmem extension can use it to guarantee that no group of processes
748 will ever exhaust kernel resources alone.
750 config KERNEL_CGROUP_PERF
751 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
752 select KERNEL_PERF_EVENTS
755 This option extends the per-cpu mode to restrict monitoring to
756 threads which belong to the cgroup specified and run on the
759 menuconfig KERNEL_CGROUP_SCHED
760 bool "Group CPU scheduler"
763 This feature lets CPU scheduler recognize task groups and control CPU
764 bandwidth allocation to such task groups. It uses cgroups to group
767 if KERNEL_CGROUP_SCHED
769 config KERNEL_FAIR_GROUP_SCHED
770 bool "Group scheduling for SCHED_OTHER"
773 config KERNEL_CFS_BANDWIDTH
774 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
776 depends on KERNEL_FAIR_GROUP_SCHED
778 This option allows users to define CPU bandwidth rates (limits) for
779 tasks running within the fair group scheduler. Groups with no limit
780 set are considered to be unconstrained and will run with no
782 See tip/Documentation/scheduler/sched-bwc.txt for more information.
784 config KERNEL_RT_GROUP_SCHED
785 bool "Group scheduling for SCHED_RR/FIFO"
788 This feature lets you explicitly allocate real CPU bandwidth
789 to task groups. If enabled, it will also make it impossible to
790 schedule realtime tasks for non-root users until you allocate
791 realtime bandwidth for them.
795 config KERNEL_BLK_CGROUP
796 bool "Block IO controller"
799 Generic block IO controller cgroup interface. This is the common
800 cgroup interface which should be used by various IO controlling
803 Currently, CFQ IO scheduler uses it to recognize task groups and
804 control disk bandwidth allocation (proportional time slice allocation)
805 to such task groups. It is also used by bio throttling logic in
806 block layer to implement upper limit in IO rates on a device.
808 This option only enables generic Block IO controller infrastructure.
809 One needs to also enable actual IO controlling logic/policy. For
810 enabling proportional weight division of disk bandwidth in CFQ, set
811 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
812 CONFIG_BLK_DEV_THROTTLING=y.
816 config KERNEL_CFQ_GROUP_IOSCHED
817 bool "Proportional weight of disk bandwidth in CFQ"
819 config KERNEL_BLK_DEV_THROTTLING
820 bool "Enable throttling policy"
823 config KERNEL_BLK_DEV_THROTTLING_LOW
824 bool "Block throttling .low limit interface support (EXPERIMENTAL)"
825 depends on KERNEL_BLK_DEV_THROTTLING
828 config KERNEL_DEBUG_BLK_CGROUP
829 bool "Enable Block IO controller debugging"
831 depends on KERNEL_BLK_CGROUP
833 Enable some debugging help. Currently it exports additional stat
834 files in a cgroup which can be useful for debugging.
836 config KERNEL_NET_CLS_CGROUP
837 bool "legacy Control Group Classifier"
840 config KERNEL_CGROUP_NET_CLASSID
841 bool "legacy Network classid cgroup"
844 config KERNEL_CGROUP_NET_PRIO
845 bool "legacy Network priority cgroup"
851 # Namespace support symbols
854 config KERNEL_NAMESPACES
855 bool "Enable kernel namespaces"
856 default y if !SMALL_FLASH
864 In this namespace, tasks see different info provided
865 with the uname() system call.
871 In this namespace, tasks work with IPC ids which correspond to
872 different IPC objects in different namespaces.
874 config KERNEL_USER_NS
875 bool "User namespace (EXPERIMENTAL)"
878 This allows containers, i.e. vservers, to use user namespaces
879 to provide different user info for different servers.
882 bool "PID Namespaces"
885 Support process id namespaces. This allows having multiple
886 processes with the same pid as long as they are in different
887 pid namespaces. This is a building block of containers.
890 bool "Network namespace"
893 Allow user space to create what appear to be multiple instances
894 of the network stack.
898 config KERNEL_DEVPTS_MULTIPLE_INSTANCES
899 bool "Support multiple instances of devpts"
900 default y if !SMALL_FLASH
902 Enable support for multiple instances of devpts filesystem.
903 If you want to have isolated PTY namespaces (eg: in containers),
904 say Y here. Otherwise, say N. If enabled, each mount of devpts
905 filesystem with the '-o newinstance' option will create an
906 independent PTY namespace.
908 config KERNEL_POSIX_MQUEUE
909 bool "POSIX Message Queues"
910 default y if !SMALL_FLASH
912 POSIX variant of message queues is a part of IPC. In POSIX message
913 queues every message has a priority which decides about succession
914 of receiving it by a process. If you want to compile and run
915 programs written e.g. for Solaris with use of its POSIX message
916 queues (functions mq_*) say Y here.
918 POSIX message queues are visible as a filesystem called 'mqueue'
919 and can be mounted somewhere if you want to do filesystem
920 operations on message queues.
923 config KERNEL_SECCOMP_FILTER
925 default y if !SMALL_FLASH
927 config KERNEL_SECCOMP
928 bool "Enable seccomp support"
929 depends on !(TARGET_uml)
930 select KERNEL_SECCOMP_FILTER
931 default y if !SMALL_FLASH
933 Build kernel with support for seccomp.
939 config KERNEL_IP_MROUTE
940 bool "Enable IPv4 multicast routing"
943 Multicast routing requires a multicast routing daemon in
944 addition to kernel support.
955 config KERNEL_IPV6_MULTIPLE_TABLES
958 config KERNEL_IPV6_SUBTREES
961 config KERNEL_IPV6_MROUTE
962 bool "Enable IPv6 multicast routing"
965 Multicast routing requires a multicast routing daemon in
966 addition to kernel support.
968 config KERNEL_IPV6_PIMSM_V2
971 config KERNEL_IPV6_SEG6_LWTUNNEL
972 bool "Enable support for lightweight tunnels"
973 default y if !SMALL_FLASH
975 Using lwtunnel (needed for IPv6 segment routing) requires ip-full package.
977 config KERNEL_LWTUNNEL_BPF
983 # NFS related symbols
986 bool "Compile the kernel with rootfs on NFS"
988 If you want to make your kernel boot off a NFS server as root
989 filesystem, select Y here.
993 config KERNEL_IP_PNP_DHCP
996 config KERNEL_IP_PNP_BOOTP
999 config KERNEL_IP_PNP_RARP
1002 config KERNEL_NFS_FS
1005 config KERNEL_NFS_V2
1008 config KERNEL_NFS_V3
1011 config KERNEL_ROOT_NFS
1016 menu "Filesystem ACL and attr support options"
1017 config USE_FS_ACL_ATTR
1018 bool "Use filesystem ACL and attr support by default"
1021 Make using ACLs (e.g. POSIX ACL, NFSv4 ACL) the default
1022 for kernel and packages, except tmpfs, flash filesystems,
1023 and old NFS. Also enable userspace extended attribute support
1024 by default. (OpenWrt already has an expection it will be
1025 present in the kernel).
1027 config KERNEL_FS_POSIX_ACL
1028 bool "Enable POSIX ACL support"
1029 default y if USE_FS_ACL_ATTR
1031 config KERNEL_BTRFS_FS_POSIX_ACL
1032 bool "Enable POSIX ACL for BtrFS Filesystems"
1033 select KERNEL_FS_POSIX_ACL
1034 default y if USE_FS_ACL_ATTR
1036 config KERNEL_EXT4_FS_POSIX_ACL
1037 bool "Enable POSIX ACL for Ext4 Filesystems"
1038 select KERNEL_FS_POSIX_ACL
1039 default y if USE_FS_ACL_ATTR
1041 config KERNEL_F2FS_FS_POSIX_ACL
1042 bool "Enable POSIX ACL for F2FS Filesystems"
1043 select KERNEL_FS_POSIX_ACL
1046 config KERNEL_JFFS2_FS_POSIX_ACL
1047 bool "Enable POSIX ACL for JFFS2 Filesystems"
1048 select KERNEL_FS_POSIX_ACL
1051 config KERNEL_TMPFS_POSIX_ACL
1052 bool "Enable POSIX ACL for TMPFS Filesystems"
1053 select KERNEL_FS_POSIX_ACL
1056 config KERNEL_CIFS_ACL
1057 bool "Enable CIFS ACLs"
1058 select KERNEL_FS_POSIX_ACL
1059 default y if USE_FS_ACL_ATTR
1061 config KERNEL_HFS_FS_POSIX_ACL
1062 bool "Enable POSIX ACL for HFS Filesystems"
1063 select KERNEL_FS_POSIX_ACL
1064 default y if USE_FS_ACL_ATTR
1066 config KERNEL_HFSPLUS_FS_POSIX_ACL
1067 bool "Enable POSIX ACL for HFS+ Filesystems"
1068 select KERNEL_FS_POSIX_ACL
1069 default y if USE_FS_ACL_ATTR
1071 config KERNEL_NFS_ACL_SUPPORT
1072 bool "Enable ACLs for NFS"
1073 default y if USE_FS_ACL_ATTR
1075 config KERNEL_NFS_V3_ACL_SUPPORT
1076 bool "Enable ACLs for NFSv3"
1079 config KERNEL_NFSD_V2_ACL_SUPPORT
1080 bool "Enable ACLs for NFSDv2"
1083 config KERNEL_NFSD_V3_ACL_SUPPORT
1084 bool "Enable ACLs for NFSDv3"
1087 config KERNEL_REISER_FS_POSIX_ACL
1088 bool "Enable POSIX ACLs for ReiserFS"
1089 select KERNEL_FS_POSIX_ACL
1090 default y if USE_FS_ACL_ATTR
1092 config KERNEL_XFS_POSIX_ACL
1093 bool "Enable POSIX ACLs for XFS"
1094 select KERNEL_FS_POSIX_ACL
1095 default y if USE_FS_ACL_ATTR
1097 config KERNEL_JFS_POSIX_ACL
1098 bool "Enable POSIX ACLs for JFS"
1099 select KERNEL_FS_POSIX_ACL
1100 default y if USE_FS_ACL_ATTR
1104 config KERNEL_DEVMEM
1105 bool "/dev/mem virtual device support"
1107 Say Y here if you want to support the /dev/mem device.
1108 The /dev/mem device is used to access areas of physical
1111 config KERNEL_DEVKMEM
1112 bool "/dev/kmem virtual device support"
1114 Say Y here if you want to support the /dev/kmem device. The
1115 /dev/kmem device is rarely used, but can be used for certain
1116 kind of kernel debugging operations.
1118 config KERNEL_SQUASHFS_FRAGMENT_CACHE_SIZE
1119 int "Number of squashfs fragments cached"
1120 default 2 if (SMALL_FLASH && !LOW_MEMORY_FOOTPRINT)
1123 config KERNEL_SQUASHFS_XATTR
1124 bool "Squashfs XATTR support"
1127 # compile optimiziation setting
1130 prompt "Compiler optimization level"
1131 default KERNEL_CC_OPTIMIZE_FOR_SIZE if SMALL_FLASH
1133 config KERNEL_CC_OPTIMIZE_FOR_PERFORMANCE
1134 bool "Optimize for performance"
1136 This is the default optimization level for the kernel, building
1137 with the "-O2" compiler flag for best performance and most
1138 helpful compile-time warnings.
1140 config KERNEL_CC_OPTIMIZE_FOR_SIZE
1141 bool "Optimize for size"
1143 Enabling this option will pass "-Os" instead of "-O2" to
1144 your compiler resulting in a smaller kernel.
1149 bool "Auditing support"
1151 config KERNEL_SECURITY
1152 bool "Enable different security models"
1154 config KERNEL_SECURITY_NETWORK
1155 bool "Socket and Networking Security Hooks"
1156 select KERNEL_SECURITY
1158 config KERNEL_SECURITY_SELINUX
1159 bool "NSA SELinux Support"
1160 select KERNEL_SECURITY_NETWORK
1163 config KERNEL_SECURITY_SELINUX_BOOTPARAM
1164 bool "NSA SELinux boot parameter"
1165 depends on KERNEL_SECURITY_SELINUX
1168 config KERNEL_SECURITY_SELINUX_DISABLE
1169 bool "NSA SELinux runtime disable"
1170 depends on KERNEL_SECURITY_SELINUX
1172 config KERNEL_SECURITY_SELINUX_DEVELOP
1173 bool "NSA SELinux Development Support"
1174 depends on KERNEL_SECURITY_SELINUX
1177 config KERNEL_SECURITY_SELINUX_SIDTAB_HASH_BITS
1179 depends on KERNEL_SECURITY_SELINUX
1182 config KERNEL_SECURITY_SELINUX_SID2STR_CACHE_SIZE
1184 depends on KERNEL_SECURITY_SELINUX
1189 default "lockdown,yama,loadpin,safesetid,integrity,selinux"
1190 depends on KERNEL_SECURITY_SELINUX
1192 config KERNEL_EXT4_FS_SECURITY
1193 bool "Ext4 Security Labels"
1195 config KERNEL_F2FS_FS_SECURITY
1196 bool "F2FS Security Labels"
1198 config KERNEL_UBIFS_FS_SECURITY
1199 bool "UBIFS Security Labels"
1201 config KERNEL_JFFS2_FS_SECURITY
1202 bool "JFFS2 Security Labels"