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"
28 bool "Support for paging of anonymous memory (swap)"
29 default y if !SMALL_FLASH
31 config KERNEL_PROC_STRIPPED
32 bool "Strip non-essential /proc functionality to reduce code size"
33 default y if SMALL_FLASH
35 config KERNEL_DEBUG_FS
36 bool "Compile the kernel with debug filesystem enabled"
39 debugfs is a virtual file system that kernel developers use to put
40 debugging files into. Enable this option to be able to read and
41 write to these files. Many common debugging facilities, such as
42 ftrace, require the existence of debugfs.
44 config KERNEL_MIPS_FP_SUPPORT
46 default y if TARGET_pistachio
51 depends on (arm || aarch64)
53 config KERNEL_X86_VSYSCALL_EMULATION
54 bool "Enable vsyscall emulation"
58 This enables emulation of the legacy vsyscall page. Disabling
59 it is roughly equivalent to booting with vsyscall=none, except
60 that it will also disable the helpful warning if a program
61 tries to use a vsyscall. With this option set to N, offending
62 programs will just segfault, citing addresses of the form
65 This option is required by many programs built before 2013, and
66 care should be used even with newer programs if set to N.
68 Disabling this option saves about 7K of kernel size and
69 possibly 4K of additional runtime pagetable memory.
71 config KERNEL_PERF_EVENTS
72 bool "Compile the kernel with performance events and counters"
74 select KERNEL_ARM_PMU if (arm || aarch64)
76 config KERNEL_PROFILING
77 bool "Compile the kernel with profiling enabled"
79 select KERNEL_PERF_EVENTS
81 Enable the extended profiling support mechanisms used by profilers such
84 config KERNEL_RPI_AXIPERF
85 bool "Compile the kernel with RaspberryPi AXI Performance monitors"
87 depends on KERNEL_PERF_EVENTS
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
173 config KERNEL_KASAN_VMALLOC
174 bool "Back mappings in vmalloc space with real shadow memory"
175 depends on KERNEL_KASAN
177 By default, the shadow region for vmalloc space is the read-only
178 zero page. This means that KASAN cannot detect errors involving
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.
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
191 config KERNEL_KASAN_GENERIC
194 config KERNEL_KASAN_SW_TAGS
199 prompt "Instrumentation type"
200 depends on KERNEL_KASAN
201 default KERNEL_KASAN_OUTLINE
203 config KERNEL_KASAN_OUTLINE
204 bool "Outline instrumentation"
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
212 config KERNEL_KASAN_INLINE
213 bool "Inline instrumentation"
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.
224 bool "Compile the kernel with code coverage for fuzzing"
225 select KERNEL_DEBUG_FS
227 KCOV exposes kernel code coverage information in a form suitable
228 for coverage-guided fuzzing (randomized testing).
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.
234 For more details, see Documentation/kcov.txt.
236 config KERNEL_KCOV_ENABLE_COMPARISONS
237 bool "Enable comparison operands collection by KCOV"
238 depends on KERNEL_KCOV
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
245 config KERNEL_KCOV_INSTRUMENT_ALL
246 bool "Instrument all code by default"
247 depends on KERNEL_KCOV
248 default y if KERNEL_KCOV
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.
256 config KERNEL_TASKSTATS
257 bool "Compile the kernel with task resource/io statistics and accounting"
260 Enable the collection and publishing of task/io statistics and
261 accounting. Enable this option to enable i/o monitoring in system
266 config KERNEL_TASK_DELAY_ACCT
269 config KERNEL_TASK_IO_ACCOUNTING
272 config KERNEL_TASK_XACCT
277 config KERNEL_KALLSYMS
278 bool "Compile the kernel with symbol table information"
279 default y if !SMALL_FLASH
281 This will give you more information in stack traces from kernel oopses.
284 bool "Compile the kernel with tracing support"
285 depends on !TARGET_uml
288 config KERNEL_FTRACE_SYSCALLS
289 bool "Trace system calls"
290 depends on KERNEL_FTRACE
293 config KERNEL_ENABLE_DEFAULT_TRACERS
294 bool "Trace process context switches and events"
295 depends on KERNEL_FTRACE
298 config KERNEL_FUNCTION_TRACER
299 bool "Function tracer"
300 depends on KERNEL_FTRACE
303 config KERNEL_FUNCTION_GRAPH_TRACER
304 bool "Function graph tracer"
305 depends on KERNEL_FUNCTION_TRACER
308 config KERNEL_DYNAMIC_FTRACE
309 bool "Enable/disable function tracing dynamically"
310 depends on KERNEL_FUNCTION_TRACER
313 config KERNEL_FUNCTION_PROFILER
314 bool "Function profiler"
315 depends on KERNEL_FUNCTION_TRACER
318 config KERNEL_IRQSOFF_TRACER
319 bool "Interrupts-off Latency Tracer"
320 depends on KERNEL_FTRACE
322 This option measures the time spent in irqs-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 preempt-off timing option can be
333 used together or separately.)
335 config KERNEL_PREEMPT_TRACER
336 bool "Preemption-off Latency Tracer"
337 depends on KERNEL_FTRACE
339 This option measures the time spent in preemption-off critical
340 sections, with microsecond accuracy.
342 The default measurement method is a maximum search, which is
343 disabled by default and can be runtime (re-)started
346 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
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.)
352 config KERNEL_HIST_TRIGGERS
353 bool "Histogram triggers"
354 depends on KERNEL_FTRACE
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.
362 Inter-event tracing of quantities such as latencies is also
363 supported using hist triggers under this option.
365 config KERNEL_DEBUG_KERNEL
369 config KERNEL_DEBUG_INFO
370 bool "Compile the kernel with debug information"
371 default y if !SMALL_FLASH
372 select KERNEL_DEBUG_KERNEL
374 This will compile your kernel and modules with debug information.
376 config KERNEL_DEBUG_LL_UART_NONE
381 config KERNEL_DEBUG_LL
385 select KERNEL_DEBUG_LL_UART_NONE
387 ARM low level debugging.
389 config KERNEL_DYNAMIC_DEBUG
390 bool "Compile the kernel with dynamic printk"
391 select KERNEL_DEBUG_FS
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%.
401 config KERNEL_EARLY_PRINTK
402 bool "Compile the kernel with early printk"
403 default y if TARGET_bcm53xx
406 select KERNEL_DEBUG_KERNEL
407 select KERNEL_DEBUG_LL if arm
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.
413 config KERNEL_KPROBES
414 bool "Compile the kernel with kprobes support"
417 select KERNEL_PERF_EVENTS
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".
426 config KERNEL_KPROBE_EVENTS
428 default y if KERNEL_KPROBES
430 config KERNEL_BPF_KPROBE_OVERRIDE
432 depends on KERNEL_KPROBES
436 bool "Compile the kernel with asynchronous IO support"
437 default y if !SMALL_FLASH
439 config KERNEL_IO_URING
440 bool "Compile the kernel with io_uring support"
441 default y if !SMALL_FLASH
443 config KERNEL_FHANDLE
444 bool "Compile the kernel with support for fhandle syscalls"
445 default y if !SMALL_FLASH
447 config KERNEL_FANOTIFY
448 bool "Compile the kernel with modern file notification support"
449 default y if !SMALL_FLASH
451 config KERNEL_BLK_DEV_BSG
452 bool "Compile the kernel with SCSI generic v4 support for any block device"
455 config KERNEL_TRANSPARENT_HUGEPAGE
459 prompt "Transparent Hugepage Support sysfs defaults"
460 depends on KERNEL_TRANSPARENT_HUGEPAGE
461 default KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
463 config KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
466 config KERNEL_TRANSPARENT_HUGEPAGE_MADVISE
470 config KERNEL_HUGETLBFS
473 config KERNEL_HUGETLB_PAGE
474 bool "Compile the kernel with HugeTLB support"
475 select KERNEL_TRANSPARENT_HUGEPAGE
476 select KERNEL_HUGETLBFS
479 config KERNEL_MAGIC_SYSRQ
480 bool "Compile the kernel with SysRq support"
483 config KERNEL_DEBUG_PINCTRL
484 bool "Compile the kernel with pinctrl debugging"
485 select KERNEL_DEBUG_KERNEL
487 config KERNEL_DEBUG_GPIO
488 bool "Compile the kernel with gpio debugging"
489 select KERNEL_DEBUG_KERNEL
491 config KERNEL_COREDUMP
494 config KERNEL_ELF_CORE
495 bool "Enable process core dump support"
496 select KERNEL_COREDUMP
497 default y if !SMALL_FLASH
499 config KERNEL_PROVE_LOCKING
500 bool "Enable kernel lock checking"
501 select KERNEL_DEBUG_KERNEL
504 config KERNEL_SOFTLOCKUP_DETECTOR
505 bool "Compile the kernel with detect Soft Lockups"
506 depends on KERNEL_DEBUG_KERNEL
508 Say Y here to enable the kernel to act as a watchdog to detect
511 Softlockups are bugs that cause the kernel to loop in kernel
512 mode for more than 20 seconds, without giving other tasks a
513 chance to run. The current stack trace is displayed upon
514 detection and the system will stay locked up.
516 config KERNEL_DETECT_HUNG_TASK
517 bool "Compile the kernel with detect Hung Tasks"
518 depends on KERNEL_DEBUG_KERNEL
519 default KERNEL_SOFTLOCKUP_DETECTOR
521 Say Y here to enable the kernel to detect "hung tasks",
522 which are bugs that cause the task to be stuck in
523 uninterruptible "D" state indefinitely.
525 When a hung task is detected, the kernel will print the
526 current stack trace (which you should report), but the
527 task will stay in uninterruptible state. If lockdep is
528 enabled then all held locks will also be reported. This
529 feature has negligible overhead.
531 config KERNEL_WQ_WATCHDOG
532 bool "Compile the kernel with detect Workqueue Stalls"
533 depends on KERNEL_DEBUG_KERNEL
535 Say Y here to enable stall detection on workqueues. If a
536 worker pool doesn't make forward progress on a pending work
537 item for over a given amount of time, 30s by default, a
538 warning message is printed along with dump of workqueue
539 state. This can be configured through kernel parameter
540 "workqueue.watchdog_thresh" and its sysfs counterpart.
542 config KERNEL_DEBUG_ATOMIC_SLEEP
543 bool "Compile the kernel with sleep inside atomic section checking"
544 depends on KERNEL_DEBUG_KERNEL
546 If you say Y here, various routines which may sleep will become very
547 noisy if they are called inside atomic sections: when a spinlock is
548 held, inside an rcu read side critical section, inside preempt disabled
549 sections, inside an interrupt, etc...
551 config KERNEL_DEBUG_VM
552 bool "Compile the kernel with debug VM"
553 depends on KERNEL_DEBUG_KERNEL
555 Enable this to turn on extended checks in the virtual-memory system
556 that may impact performance.
560 config KERNEL_PRINTK_TIME
561 bool "Enable printk timestamps"
564 config KERNEL_SLUB_DEBUG
567 config KERNEL_SLUB_DEBUG_ON
570 config KERNEL_SLABINFO
571 select KERNEL_SLUB_DEBUG
572 select KERNEL_SLUB_DEBUG_ON
573 bool "Enable /proc slab debug info"
575 config KERNEL_PROC_PAGE_MONITOR
576 bool "Enable /proc page monitoring"
582 bool "Enable kexec support"
584 config KERNEL_PROC_VMCORE
587 config KERNEL_PROC_KCORE
590 config KERNEL_CRASH_DUMP
591 depends on i386 || x86_64 || arm || armeb
593 select KERNEL_PROC_VMCORE
594 select KERNEL_PROC_KCORE
595 bool "Enable support for kexec crashdump"
599 bool "Enable rfkill support"
600 default RFKILL_SUPPORT
603 bool "Enable sparse check during kernel build"
606 config KERNEL_DEVTMPFS
607 bool "Compile the kernel with device tmpfs enabled"
610 devtmpfs is a simple, kernel-managed /dev filesystem. The kernel creates
611 devices nodes for all registered devices to simplify boot, but leaves more
612 complex tasks to userspace (e.g. udev).
616 config KERNEL_DEVTMPFS_MOUNT
617 bool "Automatically mount devtmpfs after root filesystem is mounted"
623 bool "Enable kernel access key retention support"
626 config KERNEL_PERSISTENT_KEYRINGS
627 bool "Enable kernel persistent keyrings"
628 depends on KERNEL_KEYS
631 config KERNEL_KEYS_REQUEST_CACHE
632 bool "Enable temporary caching of the last request_key() result"
633 depends on KERNEL_KEYS
636 config KERNEL_BIG_KEYS
637 bool "Enable large payload keys on kernel keyrings"
638 depends on KERNEL_KEYS
642 # CGROUP support symbols
645 config KERNEL_CGROUPS
646 bool "Enable kernel cgroups"
647 default y if !SMALL_FLASH
651 config KERNEL_CGROUP_DEBUG
652 bool "Example debug cgroup subsystem"
655 This option enables a simple cgroup subsystem that
656 exports useful debugging information about the cgroups
659 config KERNEL_FREEZER
662 config KERNEL_CGROUP_FREEZER
663 bool "legacy Freezer cgroup subsystem"
665 select KERNEL_FREEZER
667 Provides a way to freeze and unfreeze all tasks in a
669 (legacy cgroup1-only controller, in cgroup2 freezer
670 is integrated in the Memory controller)
672 config KERNEL_CGROUP_DEVICE
673 bool "legacy Device controller for cgroups"
676 Provides a cgroup implementing whitelists for devices which
677 a process in the cgroup can mknod or open.
678 (legacy cgroup1-only controller)
680 config KERNEL_CGROUP_HUGETLB
681 bool "HugeTLB controller"
683 select KERNEL_HUGETLB_PAGE
685 config KERNEL_CGROUP_PIDS
686 bool "PIDs cgroup subsystem"
689 Provides enforcement of process number limits in the scope of a
692 config KERNEL_CGROUP_RDMA
693 bool "RDMA controller for cgroups"
696 config KERNEL_CGROUP_BPF
697 bool "Support for eBPF programs attached to cgroups"
700 config KERNEL_CPUSETS
701 bool "Cpuset support"
704 This option will let you create and manage CPUSETs which
705 allow dynamically partitioning a system into sets of CPUs and
706 Memory Nodes and assigning tasks to run only within those sets.
707 This is primarily useful on large SMP or NUMA systems.
709 config KERNEL_PROC_PID_CPUSET
710 bool "Include legacy /proc/<pid>/cpuset file"
712 depends on KERNEL_CPUSETS
714 config KERNEL_CGROUP_CPUACCT
715 bool "Simple CPU accounting cgroup subsystem"
718 Provides a simple Resource Controller for monitoring the
719 total CPU consumed by the tasks in a cgroup.
721 config KERNEL_RESOURCE_COUNTERS
722 bool "Resource counters"
725 This option enables controller independent resource accounting
726 infrastructure that works with cgroups.
728 config KERNEL_MM_OWNER
730 default y if KERNEL_MEMCG
733 bool "Memory Resource Controller for Control Groups"
735 select KERNEL_FREEZER
736 depends on KERNEL_RESOURCE_COUNTERS || !LINUX_3_18
738 Provides a memory resource controller that manages both anonymous
739 memory and page cache. (See Documentation/cgroups/memory.txt)
741 Note that setting this option increases fixed memory overhead
742 associated with each page of memory in the system. By this,
743 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
744 usage tracking struct at boot. Total amount of this is printed out
747 Only enable when you're ok with these tradeoffs and really
748 sure you need the memory resource controller. Even when you enable
749 this, you can set "cgroup_disable=memory" at your boot option to
750 disable memory resource controller and you can avoid overheads
751 (but lose benefits of memory resource controller).
753 This config option also selects MM_OWNER config option, which
754 could in turn add some fork/exit overhead.
756 config KERNEL_MEMCG_SWAP
757 bool "Memory Resource Controller Swap Extension"
759 depends on KERNEL_MEMCG
761 Add swap management feature to memory resource controller. When you
762 enable this, you can limit mem+swap usage per cgroup. In other words,
763 when you disable this, memory resource controller has no cares to
764 usage of swap...a process can exhaust all of the swap. This extension
765 is useful when you want to avoid exhaustion swap but this itself
766 adds more overheads and consumes memory for remembering information.
767 Especially if you use 32bit system or small memory system, please
768 be careful about enabling this. When memory resource controller
769 is disabled by boot option, this will be automatically disabled and
770 there will be no overhead from this. Even when you set this config=y,
771 if boot option "swapaccount=0" is set, swap will not be accounted.
772 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
773 size is 4096bytes, 512k per 1Gbytes of swap.
775 config KERNEL_MEMCG_SWAP_ENABLED
776 bool "Memory Resource Controller Swap Extension enabled by default"
778 depends on KERNEL_MEMCG_SWAP
780 Memory Resource Controller Swap Extension comes with its price in
781 a bigger memory consumption. General purpose distribution kernels
782 which want to enable the feature but keep it disabled by default
783 and let the user enable it by swapaccount boot command line
784 parameter should have this option unselected.
786 Those who want to have the feature enabled by default should
787 select this option (if, for some reason, they need to disable it,
788 then swapaccount=0 does the trick).
791 config KERNEL_MEMCG_KMEM
792 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
794 depends on KERNEL_MEMCG
796 The Kernel Memory extension for Memory Resource Controller can limit
797 the amount of memory used by kernel objects in the system. Those are
798 fundamentally different from the entities handled by the standard
799 Memory Controller, which are page-based, and can be swapped. Users of
800 the kmem extension can use it to guarantee that no group of processes
801 will ever exhaust kernel resources alone.
803 config KERNEL_CGROUP_PERF
804 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
805 select KERNEL_PERF_EVENTS
808 This option extends the per-cpu mode to restrict monitoring to
809 threads which belong to the cgroup specified and run on the
812 menuconfig KERNEL_CGROUP_SCHED
813 bool "Group CPU scheduler"
816 This feature lets CPU scheduler recognize task groups and control CPU
817 bandwidth allocation to such task groups. It uses cgroups to group
820 if KERNEL_CGROUP_SCHED
822 config KERNEL_FAIR_GROUP_SCHED
823 bool "Group scheduling for SCHED_OTHER"
826 config KERNEL_CFS_BANDWIDTH
827 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
829 depends on KERNEL_FAIR_GROUP_SCHED
831 This option allows users to define CPU bandwidth rates (limits) for
832 tasks running within the fair group scheduler. Groups with no limit
833 set are considered to be unconstrained and will run with no
835 See tip/Documentation/scheduler/sched-bwc.txt for more information.
837 config KERNEL_RT_GROUP_SCHED
838 bool "Group scheduling for SCHED_RR/FIFO"
841 This feature lets you explicitly allocate real CPU bandwidth
842 to task groups. If enabled, it will also make it impossible to
843 schedule realtime tasks for non-root users until you allocate
844 realtime bandwidth for them.
848 config KERNEL_BLK_CGROUP
849 bool "Block IO controller"
852 Generic block IO controller cgroup interface. This is the common
853 cgroup interface which should be used by various IO controlling
856 Currently, CFQ IO scheduler uses it to recognize task groups and
857 control disk bandwidth allocation (proportional time slice allocation)
858 to such task groups. It is also used by bio throttling logic in
859 block layer to implement upper limit in IO rates on a device.
861 This option only enables generic Block IO controller infrastructure.
862 One needs to also enable actual IO controlling logic/policy. For
863 enabling proportional weight division of disk bandwidth in CFQ, set
864 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
865 CONFIG_BLK_DEV_THROTTLING=y.
869 config KERNEL_CFQ_GROUP_IOSCHED
870 bool "Proportional weight of disk bandwidth in CFQ"
872 config KERNEL_BLK_DEV_THROTTLING
873 bool "Enable throttling policy"
876 config KERNEL_BLK_DEV_THROTTLING_LOW
877 bool "Block throttling .low limit interface support (EXPERIMENTAL)"
878 depends on KERNEL_BLK_DEV_THROTTLING
881 config KERNEL_DEBUG_BLK_CGROUP
882 bool "Enable Block IO controller debugging"
884 depends on KERNEL_BLK_CGROUP
886 Enable some debugging help. Currently it exports additional stat
887 files in a cgroup which can be useful for debugging.
889 config KERNEL_NET_CLS_CGROUP
890 bool "legacy Control Group Classifier"
893 config KERNEL_CGROUP_NET_CLASSID
894 bool "legacy Network classid cgroup"
897 config KERNEL_CGROUP_NET_PRIO
898 bool "legacy Network priority cgroup"
904 # Namespace support symbols
907 config KERNEL_NAMESPACES
908 bool "Enable kernel namespaces"
909 default y if !SMALL_FLASH
917 In this namespace, tasks see different info provided
918 with the uname() system call.
924 In this namespace, tasks work with IPC ids which correspond to
925 different IPC objects in different namespaces.
927 config KERNEL_USER_NS
928 bool "User namespace (EXPERIMENTAL)"
931 This allows containers, i.e. vservers, to use user namespaces
932 to provide different user info for different servers.
935 bool "PID Namespaces"
938 Support process id namespaces. This allows having multiple
939 processes with the same pid as long as they are in different
940 pid namespaces. This is a building block of containers.
943 bool "Network namespace"
946 Allow user space to create what appear to be multiple instances
947 of the network stack.
951 config KERNEL_DEVPTS_MULTIPLE_INSTANCES
952 bool "Support multiple instances of devpts"
953 default y if !SMALL_FLASH
955 Enable support for multiple instances of devpts filesystem.
956 If you want to have isolated PTY namespaces (eg: in containers),
957 say Y here. Otherwise, say N. If enabled, each mount of devpts
958 filesystem with the '-o newinstance' option will create an
959 independent PTY namespace.
961 config KERNEL_POSIX_MQUEUE
962 bool "POSIX Message Queues"
963 default y if !SMALL_FLASH
965 POSIX variant of message queues is a part of IPC. In POSIX message
966 queues every message has a priority which decides about succession
967 of receiving it by a process. If you want to compile and run
968 programs written e.g. for Solaris with use of its POSIX message
969 queues (functions mq_*) say Y here.
971 POSIX message queues are visible as a filesystem called 'mqueue'
972 and can be mounted somewhere if you want to do filesystem
973 operations on message queues.
976 config KERNEL_SECCOMP_FILTER
978 default y if !SMALL_FLASH
980 config KERNEL_SECCOMP
981 bool "Enable seccomp support"
982 depends on !(TARGET_uml)
983 select KERNEL_SECCOMP_FILTER
984 default y if !SMALL_FLASH
986 Build kernel with support for seccomp.
992 config KERNEL_IP_MROUTE
993 bool "Enable IPv4 multicast routing"
996 Multicast routing requires a multicast routing daemon in
997 addition to kernel support.
1001 config KERNEL_IP_MROUTE_MULTIPLE_TABLES
1004 config KERNEL_IP_PIMSM_V1
1007 config KERNEL_IP_PIMSM_V2
1013 # IPv6 configuration
1021 config KERNEL_IPV6_MULTIPLE_TABLES
1024 config KERNEL_IPV6_SUBTREES
1027 config KERNEL_IPV6_MROUTE
1028 bool "Enable IPv6 multicast routing"
1031 Multicast routing requires a multicast routing daemon in
1032 addition to kernel support.
1034 if KERNEL_IPV6_MROUTE
1036 config KERNEL_IPV6_MROUTE_MULTIPLE_TABLES
1039 config KERNEL_IPV6_PIMSM_V2
1044 config KERNEL_IPV6_SEG6_LWTUNNEL
1045 bool "Enable support for lightweight tunnels"
1046 default y if !SMALL_FLASH
1048 Using lwtunnel (needed for IPv6 segment routing) requires ip-full package.
1050 config KERNEL_LWTUNNEL_BPF
1056 # Miscellaneous network configuration
1059 config KERNEL_NET_L3_MASTER_DEV
1060 bool "L3 Master device support"
1062 This module provides glue between core networking code and device
1063 drivers to support L3 master devices like VRF.
1066 # NFS related symbols
1068 config KERNEL_IP_PNP
1069 bool "Compile the kernel with rootfs on NFS"
1071 If you want to make your kernel boot off a NFS server as root
1072 filesystem, select Y here.
1076 config KERNEL_IP_PNP_DHCP
1079 config KERNEL_IP_PNP_BOOTP
1082 config KERNEL_IP_PNP_RARP
1085 config KERNEL_NFS_FS
1088 config KERNEL_NFS_V2
1091 config KERNEL_NFS_V3
1094 config KERNEL_ROOT_NFS
1099 menu "Filesystem ACL and attr support options"
1100 config USE_FS_ACL_ATTR
1101 bool "Use filesystem ACL and attr support by default"
1104 Make using ACLs (e.g. POSIX ACL, NFSv4 ACL) the default
1105 for kernel and packages, except tmpfs, flash filesystems,
1106 and old NFS. Also enable userspace extended attribute support
1107 by default. (OpenWrt already has an expection it will be
1108 present in the kernel).
1110 config KERNEL_FS_POSIX_ACL
1111 bool "Enable POSIX ACL support"
1112 default y if USE_FS_ACL_ATTR
1114 config KERNEL_BTRFS_FS_POSIX_ACL
1115 bool "Enable POSIX ACL for BtrFS Filesystems"
1116 select KERNEL_FS_POSIX_ACL
1117 default y if USE_FS_ACL_ATTR
1119 config KERNEL_EXT4_FS_POSIX_ACL
1120 bool "Enable POSIX ACL for Ext4 Filesystems"
1121 select KERNEL_FS_POSIX_ACL
1122 default y if USE_FS_ACL_ATTR
1124 config KERNEL_F2FS_FS_POSIX_ACL
1125 bool "Enable POSIX ACL for F2FS Filesystems"
1126 select KERNEL_FS_POSIX_ACL
1129 config KERNEL_JFFS2_FS_POSIX_ACL
1130 bool "Enable POSIX ACL for JFFS2 Filesystems"
1131 select KERNEL_FS_POSIX_ACL
1134 config KERNEL_TMPFS_POSIX_ACL
1135 bool "Enable POSIX ACL for TMPFS Filesystems"
1136 select KERNEL_FS_POSIX_ACL
1139 config KERNEL_CIFS_ACL
1140 bool "Enable CIFS ACLs"
1141 select KERNEL_FS_POSIX_ACL
1142 default y if USE_FS_ACL_ATTR
1144 config KERNEL_HFS_FS_POSIX_ACL
1145 bool "Enable POSIX ACL for HFS Filesystems"
1146 select KERNEL_FS_POSIX_ACL
1147 default y if USE_FS_ACL_ATTR
1149 config KERNEL_HFSPLUS_FS_POSIX_ACL
1150 bool "Enable POSIX ACL for HFS+ Filesystems"
1151 select KERNEL_FS_POSIX_ACL
1152 default y if USE_FS_ACL_ATTR
1154 config KERNEL_NFS_ACL_SUPPORT
1155 bool "Enable ACLs for NFS"
1156 default y if USE_FS_ACL_ATTR
1158 config KERNEL_NFS_V3_ACL_SUPPORT
1159 bool "Enable ACLs for NFSv3"
1162 config KERNEL_NFSD_V2_ACL_SUPPORT
1163 bool "Enable ACLs for NFSDv2"
1166 config KERNEL_NFSD_V3_ACL_SUPPORT
1167 bool "Enable ACLs for NFSDv3"
1170 config KERNEL_REISER_FS_POSIX_ACL
1171 bool "Enable POSIX ACLs for ReiserFS"
1172 select KERNEL_FS_POSIX_ACL
1173 default y if USE_FS_ACL_ATTR
1175 config KERNEL_XFS_POSIX_ACL
1176 bool "Enable POSIX ACLs for XFS"
1177 select KERNEL_FS_POSIX_ACL
1178 default y if USE_FS_ACL_ATTR
1180 config KERNEL_JFS_POSIX_ACL
1181 bool "Enable POSIX ACLs for JFS"
1182 select KERNEL_FS_POSIX_ACL
1183 default y if USE_FS_ACL_ATTR
1187 config KERNEL_DEVMEM
1188 bool "/dev/mem virtual device support"
1190 Say Y here if you want to support the /dev/mem device.
1191 The /dev/mem device is used to access areas of physical
1194 config KERNEL_DEVKMEM
1195 bool "/dev/kmem virtual device support"
1197 Say Y here if you want to support the /dev/kmem device. The
1198 /dev/kmem device is rarely used, but can be used for certain
1199 kind of kernel debugging operations.
1201 config KERNEL_SQUASHFS_FRAGMENT_CACHE_SIZE
1202 int "Number of squashfs fragments cached"
1203 default 2 if (SMALL_FLASH && !LOW_MEMORY_FOOTPRINT)
1206 config KERNEL_SQUASHFS_XATTR
1207 bool "Squashfs XATTR support"
1210 # compile optimization setting
1213 prompt "Compiler optimization level"
1214 default KERNEL_CC_OPTIMIZE_FOR_SIZE if SMALL_FLASH
1216 config KERNEL_CC_OPTIMIZE_FOR_PERFORMANCE
1217 bool "Optimize for performance"
1219 This is the default optimization level for the kernel, building
1220 with the "-O2" compiler flag for best performance and most
1221 helpful compile-time warnings.
1223 config KERNEL_CC_OPTIMIZE_FOR_SIZE
1224 bool "Optimize for size"
1226 Enabling this option will pass "-Os" instead of "-O2" to
1227 your compiler resulting in a smaller kernel.
1232 bool "Auditing support"
1234 config KERNEL_SECURITY
1235 bool "Enable different security models"
1237 config KERNEL_SECURITY_NETWORK
1238 bool "Socket and Networking Security Hooks"
1239 select KERNEL_SECURITY
1241 config KERNEL_SECURITY_SELINUX
1242 bool "NSA SELinux Support"
1243 select KERNEL_SECURITY_NETWORK
1246 config KERNEL_SECURITY_SELINUX_BOOTPARAM
1247 bool "NSA SELinux boot parameter"
1248 depends on KERNEL_SECURITY_SELINUX
1251 config KERNEL_SECURITY_SELINUX_DISABLE
1252 bool "NSA SELinux runtime disable"
1253 depends on KERNEL_SECURITY_SELINUX
1255 config KERNEL_SECURITY_SELINUX_DEVELOP
1256 bool "NSA SELinux Development Support"
1257 depends on KERNEL_SECURITY_SELINUX
1260 config KERNEL_SECURITY_SELINUX_SIDTAB_HASH_BITS
1262 depends on KERNEL_SECURITY_SELINUX
1265 config KERNEL_SECURITY_SELINUX_SID2STR_CACHE_SIZE
1267 depends on KERNEL_SECURITY_SELINUX
1272 default "lockdown,yama,loadpin,safesetid,integrity,selinux"
1273 depends on KERNEL_SECURITY_SELINUX
1275 config KERNEL_EXT4_FS_SECURITY
1276 bool "Ext4 Security Labels"
1278 config KERNEL_F2FS_FS_SECURITY
1279 bool "F2FS Security Labels"
1281 config KERNEL_UBIFS_FS_SECURITY
1282 bool "UBIFS Security Labels"
1284 config KERNEL_JFFS2_FS_SECURITY
1285 bool "JFFS2 Security Labels"