1 # Copyright (C) 2006-2014 OpenWrt.org
3 # This is free software, licensed under the GNU General Public License v2.
4 # See /LICENSE for more information.
7 config KERNEL_BUILD_USER
8 string "Custom Kernel Build User Name"
9 default "builder" if BUILDBOT
12 Sets the Kernel build user string, which for example will be returned
13 by 'uname -a' on running systems.
14 If not set, uses system user at build time.
16 config KERNEL_BUILD_DOMAIN
17 string "Custom Kernel Build Domain Name"
18 default "buildhost" if BUILDBOT
21 Sets the Kernel build domain string, which for example will be
22 returned by 'uname -a' on running systems.
23 If not set, uses system hostname at build time.
26 bool "Enable support for printk"
29 config KERNEL_CRASHLOG
31 depends on !(arm || powerpc || sparc || TARGET_uml || i386 || x86_64)
35 bool "Support for paging of anonymous memory (swap)"
36 default y if !SMALL_FLASH
38 config KERNEL_PROC_STRIPPED
39 bool "Strip non-essential /proc functionality to reduce code size"
40 default y if SMALL_FLASH
42 config KERNEL_DEBUG_FS
43 bool "Compile the kernel with debug filesystem enabled"
46 debugfs is a virtual file system that kernel developers use to put
47 debugging files into. Enable this option to be able to read and
48 write to these files. Many common debugging facilities, such as
49 ftrace, require the existence of debugfs.
51 config KERNEL_MIPS_FP_SUPPORT
53 default y if TARGET_pistachio
58 depends on (arm || aarch64)
60 config KERNEL_X86_VSYSCALL_EMULATION
61 bool "Enable vsyscall emulation"
65 This enables emulation of the legacy vsyscall page. Disabling
66 it is roughly equivalent to booting with vsyscall=none, except
67 that it will also disable the helpful warning if a program
68 tries to use a vsyscall. With this option set to N, offending
69 programs will just segfault, citing addresses of the form
72 This option is required by many programs built before 2013, and
73 care should be used even with newer programs if set to N.
75 Disabling this option saves about 7K of kernel size and
76 possibly 4K of additional runtime pagetable memory.
78 config KERNEL_PERF_EVENTS
79 bool "Compile the kernel with performance events and counters"
81 select KERNEL_ARM_PMU if (arm || aarch64)
83 config KERNEL_PROFILING
84 bool "Compile the kernel with profiling enabled"
86 select KERNEL_PERF_EVENTS
88 Enable the extended profiling support mechanisms used by profilers such
92 bool "Compile the kernel with undefined behaviour sanity checker"
94 This option enables undefined behaviour sanity checker
95 Compile-time instrumentation is used to detect various undefined
96 behaviours in runtime. Various types of checks may be enabled
97 via boot parameter ubsan_handle
98 (see: Documentation/dev-tools/ubsan.rst).
100 config KERNEL_UBSAN_SANITIZE_ALL
101 bool "Enable instrumentation for the entire kernel"
102 depends on KERNEL_UBSAN
105 This option activates instrumentation for the entire kernel.
106 If you don't enable this option, you have to explicitly specify
107 UBSAN_SANITIZE := y for the files/directories you want to check for UB.
108 Enabling this option will get kernel image size increased
111 config KERNEL_UBSAN_ALIGNMENT
112 bool "Enable checking of pointers alignment"
113 depends on KERNEL_UBSAN
115 This option enables detection of unaligned memory accesses.
116 Enabling this option on architectures that support unaligned
117 accesses may produce a lot of false positives.
119 config KERNEL_UBSAN_NULL
120 bool "Enable checking of null pointers"
121 depends on KERNEL_UBSAN
123 This option enables detection of memory accesses via a
127 bool "Compile the kernel with KASan: runtime memory debugger"
128 select KERNEL_SLUB_DEBUG
129 depends on (x86_64 || aarch64)
131 Enables kernel address sanitizer - runtime memory debugger,
132 designed to find out-of-bounds accesses and use-after-free bugs.
133 This is strictly a debugging feature and it requires a gcc version
134 of 4.9.2 or later. Detection of out of bounds accesses to stack or
135 global variables requires gcc 5.0 or later.
136 This feature consumes about 1/8 of available memory and brings about
137 ~x3 performance slowdown.
138 For better error detection enable CONFIG_STACKTRACE.
139 Currently CONFIG_KASAN doesn't work with CONFIG_DEBUG_SLAB
140 (the resulting kernel does not boot).
142 config KERNEL_KASAN_EXTRA
143 bool "KAsan: extra checks"
144 depends on KERNEL_KASAN && KERNEL_DEBUG_KERNEL
146 This enables further checks in the kernel address sanitizer, for now
147 it only includes the address-use-after-scope check that can lead
148 to excessive kernel stack usage, frame size warnings and longer
150 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 has more
154 prompt "Instrumentation type"
155 depends on KERNEL_KASAN
156 default KERNEL_KASAN_OUTLINE
158 config KERNEL_KASAN_OUTLINE
159 bool "Outline instrumentation"
161 Before every memory access compiler insert function call
162 __asan_load*/__asan_store*. These functions performs check
163 of shadow memory. This is slower than inline instrumentation,
164 however it doesn't bloat size of kernel's .text section so
167 config KERNEL_KASAN_INLINE
168 bool "Inline instrumentation"
170 Compiler directly inserts code checking shadow memory before
171 memory accesses. This is faster than outline (in some workloads
172 it gives about x2 boost over outline instrumentation), but
173 make kernel's .text size much bigger.
174 This requires a gcc version of 5.0 or later.
179 bool "Compile the kernel with code coverage for fuzzing"
180 select KERNEL_DEBUG_FS
182 KCOV exposes kernel code coverage information in a form suitable
183 for coverage-guided fuzzing (randomized testing).
185 If RANDOMIZE_BASE is enabled, PC values will not be stable across
186 different machines and across reboots. If you need stable PC values,
187 disable RANDOMIZE_BASE.
189 For more details, see Documentation/kcov.txt.
191 config KERNEL_KCOV_ENABLE_COMPARISONS
192 bool "Enable comparison operands collection by KCOV"
193 depends on KERNEL_KCOV
195 KCOV also exposes operands of every comparison in the instrumented
196 code along with operand sizes and PCs of the comparison instructions.
197 These operands can be used by fuzzing engines to improve the quality
200 config KERNEL_KCOV_INSTRUMENT_ALL
201 bool "Instrument all code by default"
202 depends on KERNEL_KCOV
203 default y if KERNEL_KCOV
205 If you are doing generic system call fuzzing (like e.g. syzkaller),
206 then you will want to instrument the whole kernel and you should
207 say y here. If you are doing more targeted fuzzing (like e.g.
208 filesystem fuzzing with AFL) then you will want to enable coverage
209 for more specific subsets of files, and should say n here.
211 config KERNEL_TASKSTATS
212 bool "Compile the kernel with task resource/io statistics and accounting"
215 Enable the collection and publishing of task/io statistics and
216 accounting. Enable this option to enable i/o monitoring in system
221 config KERNEL_TASK_DELAY_ACCT
224 config KERNEL_TASK_IO_ACCOUNTING
227 config KERNEL_TASK_XACCT
232 config KERNEL_KALLSYMS
233 bool "Compile the kernel with symbol table information"
234 default y if !SMALL_FLASH
236 This will give you more information in stack traces from kernel oopses.
239 bool "Compile the kernel with tracing support"
240 depends on !TARGET_uml
243 config KERNEL_FTRACE_SYSCALLS
244 bool "Trace system calls"
245 depends on KERNEL_FTRACE
248 config KERNEL_ENABLE_DEFAULT_TRACERS
249 bool "Trace process context switches and events"
250 depends on KERNEL_FTRACE
253 config KERNEL_FUNCTION_TRACER
254 bool "Function tracer"
255 depends on KERNEL_FTRACE
258 config KERNEL_FUNCTION_GRAPH_TRACER
259 bool "Function graph tracer"
260 depends on KERNEL_FUNCTION_TRACER
263 config KERNEL_DYNAMIC_FTRACE
264 bool "Enable/disable function tracing dynamically"
265 depends on KERNEL_FUNCTION_TRACER
268 config KERNEL_FUNCTION_PROFILER
269 bool "Function profiler"
270 depends on KERNEL_FUNCTION_TRACER
273 config KERNEL_IRQSOFF_TRACER
274 bool "Interrupts-off Latency Tracer"
275 depends on KERNEL_FTRACE
277 This option measures the time spent in irqs-off critical
278 sections, with microsecond accuracy.
280 The default measurement method is a maximum search, which is
281 disabled by default and can be runtime (re-)started
284 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
286 (Note that kernel size and overhead increase with this option
287 enabled. This option and the preempt-off timing option can be
288 used together or separately.)
290 config KERNEL_PREEMPT_TRACER
291 bool "Preemption-off Latency Tracer"
292 depends on KERNEL_FTRACE
294 This option measures the time spent in preemption-off critical
295 sections, with microsecond accuracy.
297 The default measurement method is a maximum search, which is
298 disabled by default and can be runtime (re-)started
301 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
303 (Note that kernel size and overhead increase with this option
304 enabled. This option and the irqs-off timing option can be
305 used together or separately.)
307 config KERNEL_DEBUG_KERNEL
311 config KERNEL_DEBUG_INFO
312 bool "Compile the kernel with debug information"
313 default y if !SMALL_FLASH
314 select KERNEL_DEBUG_KERNEL
316 This will compile your kernel and modules with debug information.
318 config KERNEL_DEBUG_LL_UART_NONE
323 config KERNEL_DEBUG_LL
327 select KERNEL_DEBUG_LL_UART_NONE
329 ARM low level debugging.
331 config KERNEL_DYNAMIC_DEBUG
332 bool "Compile the kernel with dynamic printk"
333 select KERNEL_DEBUG_FS
336 Compiles debug level messages into the kernel, which would not
337 otherwise be available at runtime. These messages can then be
338 enabled/disabled based on various levels of scope - per source file,
339 function, module, format string, and line number. This mechanism
340 implicitly compiles in all pr_debug() and dev_dbg() calls, which
341 enlarges the kernel text size by about 2%.
343 config KERNEL_EARLY_PRINTK
344 bool "Compile the kernel with early printk"
345 default y if TARGET_bcm53xx
348 select KERNEL_DEBUG_KERNEL
349 select KERNEL_DEBUG_LL if arm
351 Compile the kernel with early printk support. This is only useful for
352 debugging purposes to send messages over the serial console in early boot.
353 Enable this to debug early boot problems.
355 config KERNEL_KPROBES
356 bool "Compile the kernel with kprobes support"
359 select KERNEL_PERF_EVENTS
361 Compiles the kernel with KPROBES support, which allows you to trap
362 at almost any kernel address and execute a callback function.
363 register_kprobe() establishes a probepoint and specifies the
364 callback. Kprobes is useful for kernel debugging, non-intrusive
365 instrumentation and testing.
366 If in doubt, say "N".
368 config KERNEL_KPROBE_EVENT
370 default y if KERNEL_KPROBES
372 config KERNEL_KPROBE_EVENTS
374 default y if KERNEL_KPROBES
377 bool "Compile the kernel with asynchronous IO support"
378 default y if !SMALL_FLASH
380 config KERNEL_IO_URING
381 bool "Compile the kernel with io_uring support"
382 default y if !SMALL_FLASH
384 config KERNEL_FHANDLE
385 bool "Compile the kernel with support for fhandle syscalls"
386 default y if !SMALL_FLASH
388 config KERNEL_FANOTIFY
389 bool "Compile the kernel with modern file notification support"
390 default y if !SMALL_FLASH
392 config KERNEL_BLK_DEV_BSG
393 bool "Compile the kernel with SCSI generic v4 support for any block device"
396 config KERNEL_TRANSPARENT_HUGEPAGE
400 prompt "Transparent Hugepage Support sysfs defaults"
401 depends on KERNEL_TRANSPARENT_HUGEPAGE
402 default KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
404 config KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
407 config KERNEL_TRANSPARENT_HUGEPAGE_MADVISE
411 config KERNEL_HUGETLBFS
414 config KERNEL_HUGETLB_PAGE
415 bool "Compile the kernel with HugeTLB support"
416 select KERNEL_TRANSPARENT_HUGEPAGE
417 select KERNEL_HUGETLBFS
420 config KERNEL_MAGIC_SYSRQ
421 bool "Compile the kernel with SysRq support"
424 config KERNEL_DEBUG_PINCTRL
425 bool "Compile the kernel with pinctrl debugging"
426 select KERNEL_DEBUG_KERNEL
428 config KERNEL_DEBUG_GPIO
429 bool "Compile the kernel with gpio debugging"
430 select KERNEL_DEBUG_KERNEL
432 config KERNEL_COREDUMP
435 config KERNEL_ELF_CORE
436 bool "Enable process core dump support"
437 select KERNEL_COREDUMP
438 default y if !SMALL_FLASH
440 config KERNEL_PROVE_LOCKING
441 bool "Enable kernel lock checking"
442 select KERNEL_DEBUG_KERNEL
445 config KERNEL_LOCKUP_DETECTOR
446 bool "Compile the kernel with detect Hard and Soft Lockups"
447 depends on KERNEL_DEBUG_KERNEL
449 Say Y here to enable the kernel to act as a watchdog to detect
450 hard and soft lockups.
452 Softlockups are bugs that cause the kernel to loop in kernel
453 mode for more than 20 seconds, without giving other tasks a
454 chance to run. The current stack trace is displayed upon
455 detection and the system will stay locked up.
457 Hardlockups are bugs that cause the CPU to loop in kernel mode
458 for more than 10 seconds, without letting other interrupts have a
459 chance to run. The current stack trace is displayed upon detection
460 and the system will stay locked up.
462 The overhead should be minimal. A periodic hrtimer runs to
463 generate interrupts and kick the watchdog task every 4 seconds.
464 An NMI is generated every 10 seconds or so to check for hardlockups.
466 The frequency of hrtimer and NMI events and the soft and hard lockup
467 thresholds can be controlled through the sysctl watchdog_thresh.
469 config KERNEL_DETECT_HUNG_TASK
470 bool "Compile the kernel with detect Hung Tasks"
471 depends on KERNEL_DEBUG_KERNEL
472 default KERNEL_LOCKUP_DETECTOR
474 Say Y here to enable the kernel to detect "hung tasks",
475 which are bugs that cause the task to be stuck in
476 uninterruptible "D" state indefinitely.
478 When a hung task is detected, the kernel will print the
479 current stack trace (which you should report), but the
480 task will stay in uninterruptible state. If lockdep is
481 enabled then all held locks will also be reported. This
482 feature has negligible overhead.
484 config KERNEL_WQ_WATCHDOG
485 bool "Compile the kernel with detect Workqueue Stalls"
486 depends on KERNEL_DEBUG_KERNEL
488 Say Y here to enable stall detection on workqueues. If a
489 worker pool doesn't make forward progress on a pending work
490 item for over a given amount of time, 30s by default, a
491 warning message is printed along with dump of workqueue
492 state. This can be configured through kernel parameter
493 "workqueue.watchdog_thresh" and its sysfs counterpart.
495 config KERNEL_DEBUG_ATOMIC_SLEEP
496 bool "Compile the kernel with sleep inside atomic section checking"
497 depends on KERNEL_DEBUG_KERNEL
499 If you say Y here, various routines which may sleep will become very
500 noisy if they are called inside atomic sections: when a spinlock is
501 held, inside an rcu read side critical section, inside preempt disabled
502 sections, inside an interrupt, etc...
504 config KERNEL_DEBUG_VM
505 bool "Compile the kernel with debug VM"
506 depends on KERNEL_DEBUG_KERNEL
508 Enable this to turn on extended checks in the virtual-memory system
509 that may impact performance.
513 config KERNEL_PRINTK_TIME
514 bool "Enable printk timestamps"
517 config KERNEL_SLUB_DEBUG
520 config KERNEL_SLUB_DEBUG_ON
523 config KERNEL_SLABINFO
524 select KERNEL_SLUB_DEBUG
525 select KERNEL_SLUB_DEBUG_ON
526 bool "Enable /proc slab debug info"
528 config KERNEL_PROC_PAGE_MONITOR
529 bool "Enable /proc page monitoring"
535 bool "Enable kexec support"
537 config KERNEL_PROC_VMCORE
540 config KERNEL_PROC_KCORE
543 config KERNEL_CRASH_DUMP
544 depends on i386 || x86_64 || arm || armeb
546 select KERNEL_PROC_VMCORE
547 select KERNEL_PROC_KCORE
548 bool "Enable support for kexec crashdump"
552 bool "Enable rfkill support"
553 default RFKILL_SUPPORT
556 bool "Enable sparse check during kernel build"
559 config KERNEL_DEVTMPFS
560 bool "Compile the kernel with device tmpfs enabled"
563 devtmpfs is a simple, kernel-managed /dev filesystem. The kernel creates
564 devices nodes for all registered devices to simplify boot, but leaves more
565 complex tasks to userspace (e.g. udev).
569 config KERNEL_DEVTMPFS_MOUNT
570 bool "Automatically mount devtmpfs after root filesystem is mounted"
576 bool "Enable kernel access key retention support"
579 config KERNEL_PERSISTENT_KEYRINGS
580 bool "Enable kernel persistent keyrings"
581 depends on KERNEL_KEYS
584 config KERNEL_KEYS_REQUEST_CACHE
585 bool "Enable temporary caching of the last request_key() result"
586 depends on KERNEL_KEYS
589 config KERNEL_BIG_KEYS
590 bool "Enable large payload keys on kernel keyrings"
591 depends on KERNEL_KEYS
595 # CGROUP support symbols
598 config KERNEL_CGROUPS
599 bool "Enable kernel cgroups"
600 default y if !SMALL_FLASH
604 config KERNEL_CGROUP_DEBUG
605 bool "Example debug cgroup subsystem"
608 This option enables a simple cgroup subsystem that
609 exports useful debugging information about the cgroups
612 config KERNEL_FREEZER
615 config KERNEL_CGROUP_FREEZER
616 bool "legacy Freezer cgroup subsystem"
618 select KERNEL_FREEZER
620 Provides a way to freeze and unfreeze all tasks in a
622 (legacy cgroup1-only controller, in cgroup2 freezer
623 is integrated in the Memory controller)
625 config KERNEL_CGROUP_DEVICE
626 bool "legacy Device controller for cgroups"
629 Provides a cgroup implementing whitelists for devices which
630 a process in the cgroup can mknod or open.
631 (legacy cgroup1-only controller)
633 config KERNEL_CGROUP_HUGETLB
634 bool "HugeTLB controller"
636 select KERNEL_HUGETLB_PAGE
638 config KERNEL_CGROUP_PIDS
639 bool "PIDs cgroup subsystem"
642 Provides enforcement of process number limits in the scope of a
645 config KERNEL_CGROUP_RDMA
646 bool "RDMA controller for cgroups"
649 config KERNEL_CGROUP_BPF
650 bool "Support for eBPF programs attached to cgroups"
653 config KERNEL_CPUSETS
654 bool "Cpuset support"
657 This option will let you create and manage CPUSETs which
658 allow dynamically partitioning a system into sets of CPUs and
659 Memory Nodes and assigning tasks to run only within those sets.
660 This is primarily useful on large SMP or NUMA systems.
662 config KERNEL_PROC_PID_CPUSET
663 bool "Include legacy /proc/<pid>/cpuset file"
665 depends on KERNEL_CPUSETS
667 config KERNEL_CGROUP_CPUACCT
668 bool "Simple CPU accounting cgroup subsystem"
671 Provides a simple Resource Controller for monitoring the
672 total CPU consumed by the tasks in a cgroup.
674 config KERNEL_RESOURCE_COUNTERS
675 bool "Resource counters"
678 This option enables controller independent resource accounting
679 infrastructure that works with cgroups.
681 config KERNEL_MM_OWNER
683 default y if KERNEL_MEMCG
686 bool "Memory Resource Controller for Control Groups"
688 select KERNEL_FREEZER
689 depends on KERNEL_RESOURCE_COUNTERS || !LINUX_3_18
691 Provides a memory resource controller that manages both anonymous
692 memory and page cache. (See Documentation/cgroups/memory.txt)
694 Note that setting this option increases fixed memory overhead
695 associated with each page of memory in the system. By this,
696 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
697 usage tracking struct at boot. Total amount of this is printed out
700 Only enable when you're ok with these tradeoffs and really
701 sure you need the memory resource controller. Even when you enable
702 this, you can set "cgroup_disable=memory" at your boot option to
703 disable memory resource controller and you can avoid overheads
704 (but lose benefits of memory resource controller).
706 This config option also selects MM_OWNER config option, which
707 could in turn add some fork/exit overhead.
709 config KERNEL_MEMCG_SWAP
710 bool "Memory Resource Controller Swap Extension"
712 depends on KERNEL_MEMCG
714 Add swap management feature to memory resource controller. When you
715 enable this, you can limit mem+swap usage per cgroup. In other words,
716 when you disable this, memory resource controller has no cares to
717 usage of swap...a process can exhaust all of the swap. This extension
718 is useful when you want to avoid exhaustion swap but this itself
719 adds more overheads and consumes memory for remembering information.
720 Especially if you use 32bit system or small memory system, please
721 be careful about enabling this. When memory resource controller
722 is disabled by boot option, this will be automatically disabled and
723 there will be no overhead from this. Even when you set this config=y,
724 if boot option "swapaccount=0" is set, swap will not be accounted.
725 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
726 size is 4096bytes, 512k per 1Gbytes of swap.
728 config KERNEL_MEMCG_SWAP_ENABLED
729 bool "Memory Resource Controller Swap Extension enabled by default"
731 depends on KERNEL_MEMCG_SWAP
733 Memory Resource Controller Swap Extension comes with its price in
734 a bigger memory consumption. General purpose distribution kernels
735 which want to enable the feature but keep it disabled by default
736 and let the user enable it by swapaccount boot command line
737 parameter should have this option unselected.
739 Those who want to have the feature enabled by default should
740 select this option (if, for some reason, they need to disable it,
741 then swapaccount=0 does the trick).
744 config KERNEL_MEMCG_KMEM
745 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
747 depends on KERNEL_MEMCG
749 The Kernel Memory extension for Memory Resource Controller can limit
750 the amount of memory used by kernel objects in the system. Those are
751 fundamentally different from the entities handled by the standard
752 Memory Controller, which are page-based, and can be swapped. Users of
753 the kmem extension can use it to guarantee that no group of processes
754 will ever exhaust kernel resources alone.
756 config KERNEL_CGROUP_PERF
757 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
758 select KERNEL_PERF_EVENTS
761 This option extends the per-cpu mode to restrict monitoring to
762 threads which belong to the cgroup specified and run on the
765 menuconfig KERNEL_CGROUP_SCHED
766 bool "Group CPU scheduler"
769 This feature lets CPU scheduler recognize task groups and control CPU
770 bandwidth allocation to such task groups. It uses cgroups to group
773 if KERNEL_CGROUP_SCHED
775 config KERNEL_FAIR_GROUP_SCHED
776 bool "Group scheduling for SCHED_OTHER"
779 config KERNEL_CFS_BANDWIDTH
780 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
782 depends on KERNEL_FAIR_GROUP_SCHED
784 This option allows users to define CPU bandwidth rates (limits) for
785 tasks running within the fair group scheduler. Groups with no limit
786 set are considered to be unconstrained and will run with no
788 See tip/Documentation/scheduler/sched-bwc.txt for more information.
790 config KERNEL_RT_GROUP_SCHED
791 bool "Group scheduling for SCHED_RR/FIFO"
794 This feature lets you explicitly allocate real CPU bandwidth
795 to task groups. If enabled, it will also make it impossible to
796 schedule realtime tasks for non-root users until you allocate
797 realtime bandwidth for them.
801 config KERNEL_BLK_CGROUP
802 bool "Block IO controller"
805 Generic block IO controller cgroup interface. This is the common
806 cgroup interface which should be used by various IO controlling
809 Currently, CFQ IO scheduler uses it to recognize task groups and
810 control disk bandwidth allocation (proportional time slice allocation)
811 to such task groups. It is also used by bio throttling logic in
812 block layer to implement upper limit in IO rates on a device.
814 This option only enables generic Block IO controller infrastructure.
815 One needs to also enable actual IO controlling logic/policy. For
816 enabling proportional weight division of disk bandwidth in CFQ, set
817 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
818 CONFIG_BLK_DEV_THROTTLING=y.
822 config KERNEL_CFQ_GROUP_IOSCHED
823 bool "Proportional weight of disk bandwidth in CFQ"
825 config KERNEL_BLK_DEV_THROTTLING
826 bool "Enable throttling policy"
829 config KERNEL_BLK_DEV_THROTTLING_LOW
830 bool "Block throttling .low limit interface support (EXPERIMENTAL)"
831 depends on KERNEL_BLK_DEV_THROTTLING
834 config KERNEL_DEBUG_BLK_CGROUP
835 bool "Enable Block IO controller debugging"
837 depends on KERNEL_BLK_CGROUP
839 Enable some debugging help. Currently it exports additional stat
840 files in a cgroup which can be useful for debugging.
842 config KERNEL_NET_CLS_CGROUP
843 bool "legacy Control Group Classifier"
846 config KERNEL_CGROUP_NET_CLASSID
847 bool "legacy Network classid cgroup"
850 config KERNEL_CGROUP_NET_PRIO
851 bool "legacy Network priority cgroup"
857 # Namespace support symbols
860 config KERNEL_NAMESPACES
861 bool "Enable kernel namespaces"
862 default y if !SMALL_FLASH
870 In this namespace, tasks see different info provided
871 with the uname() system call.
877 In this namespace, tasks work with IPC ids which correspond to
878 different IPC objects in different namespaces.
880 config KERNEL_USER_NS
881 bool "User namespace (EXPERIMENTAL)"
884 This allows containers, i.e. vservers, to use user namespaces
885 to provide different user info for different servers.
888 bool "PID Namespaces"
891 Support process id namespaces. This allows having multiple
892 processes with the same pid as long as they are in different
893 pid namespaces. This is a building block of containers.
896 bool "Network namespace"
899 Allow user space to create what appear to be multiple instances
900 of the network stack.
904 config KERNEL_DEVPTS_MULTIPLE_INSTANCES
905 bool "Support multiple instances of devpts"
906 default y if !SMALL_FLASH
908 Enable support for multiple instances of devpts filesystem.
909 If you want to have isolated PTY namespaces (eg: in containers),
910 say Y here. Otherwise, say N. If enabled, each mount of devpts
911 filesystem with the '-o newinstance' option will create an
912 independent PTY namespace.
914 config KERNEL_POSIX_MQUEUE
915 bool "POSIX Message Queues"
916 default y if !SMALL_FLASH
918 POSIX variant of message queues is a part of IPC. In POSIX message
919 queues every message has a priority which decides about succession
920 of receiving it by a process. If you want to compile and run
921 programs written e.g. for Solaris with use of its POSIX message
922 queues (functions mq_*) say Y here.
924 POSIX message queues are visible as a filesystem called 'mqueue'
925 and can be mounted somewhere if you want to do filesystem
926 operations on message queues.
929 config KERNEL_SECCOMP_FILTER
931 default y if !SMALL_FLASH
933 config KERNEL_SECCOMP
934 bool "Enable seccomp support"
935 depends on !(TARGET_uml)
936 select KERNEL_SECCOMP_FILTER
937 default y if !SMALL_FLASH
939 Build kernel with support for seccomp.
945 config KERNEL_IP_MROUTE
946 bool "Enable IPv4 multicast routing"
949 Multicast routing requires a multicast routing daemon in
950 addition to kernel support.
961 config KERNEL_IPV6_MULTIPLE_TABLES
964 config KERNEL_IPV6_SUBTREES
967 config KERNEL_IPV6_MROUTE
968 bool "Enable IPv6 multicast routing"
971 Multicast routing requires a multicast routing daemon in
972 addition to kernel support.
974 config KERNEL_IPV6_PIMSM_V2
977 config KERNEL_IPV6_SEG6_LWTUNNEL
978 bool "Enable support for lightweight tunnels"
979 default y if !SMALL_FLASH
981 Using lwtunnel (needed for IPv6 segment routing) requires ip-full package.
983 config KERNEL_LWTUNNEL_BPF
989 # NFS related symbols
992 bool "Compile the kernel with rootfs on NFS"
994 If you want to make your kernel boot off a NFS server as root
995 filesystem, select Y here.
999 config KERNEL_IP_PNP_DHCP
1002 config KERNEL_IP_PNP_BOOTP
1005 config KERNEL_IP_PNP_RARP
1008 config KERNEL_NFS_FS
1011 config KERNEL_NFS_V2
1014 config KERNEL_NFS_V3
1017 config KERNEL_ROOT_NFS
1022 menu "Filesystem ACL and attr support options"
1023 config USE_FS_ACL_ATTR
1024 bool "Use filesystem ACL and attr support by default"
1027 Make using ACLs (e.g. POSIX ACL, NFSv4 ACL) the default
1028 for kernel and packages, except tmpfs, flash filesystems,
1029 and old NFS. Also enable userspace extended attribute support
1030 by default. (OpenWrt already has an expection it will be
1031 present in the kernel).
1033 config KERNEL_FS_POSIX_ACL
1034 bool "Enable POSIX ACL support"
1035 default y if USE_FS_ACL_ATTR
1037 config KERNEL_BTRFS_FS_POSIX_ACL
1038 bool "Enable POSIX ACL for BtrFS Filesystems"
1039 select KERNEL_FS_POSIX_ACL
1040 default y if USE_FS_ACL_ATTR
1042 config KERNEL_EXT4_FS_POSIX_ACL
1043 bool "Enable POSIX ACL for Ext4 Filesystems"
1044 select KERNEL_FS_POSIX_ACL
1045 default y if USE_FS_ACL_ATTR
1047 config KERNEL_F2FS_FS_POSIX_ACL
1048 bool "Enable POSIX ACL for F2FS Filesystems"
1049 select KERNEL_FS_POSIX_ACL
1052 config KERNEL_JFFS2_FS_POSIX_ACL
1053 bool "Enable POSIX ACL for JFFS2 Filesystems"
1054 select KERNEL_FS_POSIX_ACL
1057 config KERNEL_TMPFS_POSIX_ACL
1058 bool "Enable POSIX ACL for TMPFS Filesystems"
1059 select KERNEL_FS_POSIX_ACL
1062 config KERNEL_CIFS_ACL
1063 bool "Enable CIFS ACLs"
1064 select KERNEL_FS_POSIX_ACL
1065 default y if USE_FS_ACL_ATTR
1067 config KERNEL_HFS_FS_POSIX_ACL
1068 bool "Enable POSIX ACL for HFS Filesystems"
1069 select KERNEL_FS_POSIX_ACL
1070 default y if USE_FS_ACL_ATTR
1072 config KERNEL_HFSPLUS_FS_POSIX_ACL
1073 bool "Enable POSIX ACL for HFS+ Filesystems"
1074 select KERNEL_FS_POSIX_ACL
1075 default y if USE_FS_ACL_ATTR
1077 config KERNEL_NFS_ACL_SUPPORT
1078 bool "Enable ACLs for NFS"
1079 default y if USE_FS_ACL_ATTR
1081 config KERNEL_NFS_V3_ACL_SUPPORT
1082 bool "Enable ACLs for NFSv3"
1085 config KERNEL_NFSD_V2_ACL_SUPPORT
1086 bool "Enable ACLs for NFSDv2"
1089 config KERNEL_NFSD_V3_ACL_SUPPORT
1090 bool "Enable ACLs for NFSDv3"
1093 config KERNEL_REISER_FS_POSIX_ACL
1094 bool "Enable POSIX ACLs for ReiserFS"
1095 select KERNEL_FS_POSIX_ACL
1096 default y if USE_FS_ACL_ATTR
1098 config KERNEL_XFS_POSIX_ACL
1099 bool "Enable POSIX ACLs for XFS"
1100 select KERNEL_FS_POSIX_ACL
1101 default y if USE_FS_ACL_ATTR
1103 config KERNEL_JFS_POSIX_ACL
1104 bool "Enable POSIX ACLs for JFS"
1105 select KERNEL_FS_POSIX_ACL
1106 default y if USE_FS_ACL_ATTR
1110 config KERNEL_DEVMEM
1111 bool "/dev/mem virtual device support"
1113 Say Y here if you want to support the /dev/mem device.
1114 The /dev/mem device is used to access areas of physical
1117 config KERNEL_DEVKMEM
1118 bool "/dev/kmem virtual device support"
1120 Say Y here if you want to support the /dev/kmem device. The
1121 /dev/kmem device is rarely used, but can be used for certain
1122 kind of kernel debugging operations.
1124 config KERNEL_SQUASHFS_FRAGMENT_CACHE_SIZE
1125 int "Number of squashfs fragments cached"
1126 default 2 if (SMALL_FLASH && !LOW_MEMORY_FOOTPRINT)
1129 config KERNEL_SQUASHFS_XATTR
1130 bool "Squashfs XATTR support"
1133 # compile optimiziation setting
1136 prompt "Compiler optimization level"
1137 default KERNEL_CC_OPTIMIZE_FOR_SIZE if SMALL_FLASH
1139 config KERNEL_CC_OPTIMIZE_FOR_PERFORMANCE
1140 bool "Optimize for performance"
1142 This is the default optimization level for the kernel, building
1143 with the "-O2" compiler flag for best performance and most
1144 helpful compile-time warnings.
1146 config KERNEL_CC_OPTIMIZE_FOR_SIZE
1147 bool "Optimize for size"
1149 Enabling this option will pass "-Os" instead of "-O2" to
1150 your compiler resulting in a smaller kernel.
1155 bool "Auditing support"
1157 config KERNEL_SECURITY
1158 bool "Enable different security models"
1160 config KERNEL_SECURITY_NETWORK
1161 bool "Socket and Networking Security Hooks"
1162 select KERNEL_SECURITY
1164 config KERNEL_SECURITY_SELINUX
1165 bool "NSA SELinux Support"
1166 select KERNEL_SECURITY_NETWORK
1169 config KERNEL_SECURITY_SELINUX_BOOTPARAM
1170 bool "NSA SELinux boot parameter"
1171 depends on KERNEL_SECURITY_SELINUX
1174 config KERNEL_SECURITY_SELINUX_DISABLE
1175 bool "NSA SELinux runtime disable"
1176 depends on KERNEL_SECURITY_SELINUX
1178 config KERNEL_SECURITY_SELINUX_DEVELOP
1179 bool "NSA SELinux Development Support"
1180 depends on KERNEL_SECURITY_SELINUX
1185 default "lockdown,yama,loadpin,safesetid,integrity,selinux"
1186 depends on KERNEL_SECURITY_SELINUX
1188 config KERNEL_EXT4_FS_SECURITY
1189 bool "Ext4 Security Labels"
1191 config KERNEL_F2FS_FS_SECURITY
1192 bool "F2FS Security Labels"
1194 config KERNEL_UBIFS_FS_SECURITY
1195 bool "UBIFS Security Labels"
1197 config KERNEL_JFFS2_FS_SECURITY
1198 bool "JFFS2 Security Labels"