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_DEBUG_FS
39 bool "Compile the kernel with debug filesystem enabled"
42 debugfs is a virtual file system that kernel developers use to put
43 debugging files into. Enable this option to be able to read and
44 write to these files. Many common debugging facilities, such as
45 ftrace, require the existence of debugfs.
47 # remove KERNEL_MIPS_FPU_EMULATOR after kernel 4.14 and 4.14 are gone
48 config KERNEL_MIPS_FPU_EMULATOR
49 bool "Compile the kernel with MIPS FPU Emulator"
50 default y if TARGET_pistachio
51 depends on (mips || mipsel || mips64 || mips64el)
53 config KERNEL_MIPS_FP_SUPPORT
55 default y if KERNEL_MIPS_FPU_EMULATOR
60 depends on (arm || aarch64)
62 config KERNEL_X86_VSYSCALL_EMULATION
63 bool "Enable vsyscall emulation"
67 This enables emulation of the legacy vsyscall page. Disabling
68 it is roughly equivalent to booting with vsyscall=none, except
69 that it will also disable the helpful warning if a program
70 tries to use a vsyscall. With this option set to N, offending
71 programs will just segfault, citing addresses of the form
74 This option is required by many programs built before 2013, and
75 care should be used even with newer programs if set to N.
77 Disabling this option saves about 7K of kernel size and
78 possibly 4K of additional runtime pagetable memory.
80 config KERNEL_PERF_EVENTS
81 bool "Compile the kernel with performance events and counters"
83 select KERNEL_ARM_PMU if (arm || aarch64)
85 config KERNEL_PROFILING
86 bool "Compile the kernel with profiling enabled"
88 select KERNEL_PERF_EVENTS
90 Enable the extended profiling support mechanisms used by profilers such
94 bool "Compile the kernel with undefined behaviour sanity checker"
96 This option enables undefined behaviour sanity checker
97 Compile-time instrumentation is used to detect various undefined
98 behaviours in runtime. Various types of checks may be enabled
99 via boot parameter ubsan_handle
100 (see: Documentation/dev-tools/ubsan.rst).
102 config KERNEL_UBSAN_SANITIZE_ALL
103 bool "Enable instrumentation for the entire kernel"
104 depends on KERNEL_UBSAN
107 This option activates instrumentation for the entire kernel.
108 If you don't enable this option, you have to explicitly specify
109 UBSAN_SANITIZE := y for the files/directories you want to check for UB.
110 Enabling this option will get kernel image size increased
113 config KERNEL_UBSAN_ALIGNMENT
114 bool "Enable checking of pointers alignment"
115 depends on KERNEL_UBSAN
117 This option enables detection of unaligned memory accesses.
118 Enabling this option on architectures that support unaligned
119 accesses may produce a lot of false positives.
121 config KERNEL_UBSAN_NULL
122 bool "Enable checking of null pointers"
123 depends on KERNEL_UBSAN
125 This option enables detection of memory accesses via a
129 bool "Compile the kernel with KASan: runtime memory debugger"
130 select KERNEL_SLUB_DEBUG
131 depends on (x86_64 || aarch64)
133 Enables kernel address sanitizer - runtime memory debugger,
134 designed to find out-of-bounds accesses and use-after-free bugs.
135 This is strictly a debugging feature and it requires a gcc version
136 of 4.9.2 or later. Detection of out of bounds accesses to stack or
137 global variables requires gcc 5.0 or later.
138 This feature consumes about 1/8 of available memory and brings about
139 ~x3 performance slowdown.
140 For better error detection enable CONFIG_STACKTRACE.
141 Currently CONFIG_KASAN doesn't work with CONFIG_DEBUG_SLAB
142 (the resulting kernel does not boot).
144 config KERNEL_KASAN_EXTRA
145 bool "KAsan: extra checks"
146 depends on KERNEL_KASAN && KERNEL_DEBUG_KERNEL
148 This enables further checks in the kernel address sanitizer, for now
149 it only includes the address-use-after-scope check that can lead
150 to excessive kernel stack usage, frame size warnings and longer
152 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 has more
156 prompt "Instrumentation type"
157 depends on KERNEL_KASAN
158 default KERNEL_KASAN_OUTLINE
160 config KERNEL_KASAN_OUTLINE
161 bool "Outline instrumentation"
163 Before every memory access compiler insert function call
164 __asan_load*/__asan_store*. These functions performs check
165 of shadow memory. This is slower than inline instrumentation,
166 however it doesn't bloat size of kernel's .text section so
169 config KERNEL_KASAN_INLINE
170 bool "Inline instrumentation"
172 Compiler directly inserts code checking shadow memory before
173 memory accesses. This is faster than outline (in some workloads
174 it gives about x2 boost over outline instrumentation), but
175 make kernel's .text size much bigger.
176 This requires a gcc version of 5.0 or later.
181 bool "Compile the kernel with code coverage for fuzzing"
182 select KERNEL_DEBUG_FS
184 KCOV exposes kernel code coverage information in a form suitable
185 for coverage-guided fuzzing (randomized testing).
187 If RANDOMIZE_BASE is enabled, PC values will not be stable across
188 different machines and across reboots. If you need stable PC values,
189 disable RANDOMIZE_BASE.
191 For more details, see Documentation/kcov.txt.
193 config KERNEL_KCOV_ENABLE_COMPARISONS
194 bool "Enable comparison operands collection by KCOV"
195 depends on KERNEL_KCOV
197 KCOV also exposes operands of every comparison in the instrumented
198 code along with operand sizes and PCs of the comparison instructions.
199 These operands can be used by fuzzing engines to improve the quality
202 config KERNEL_KCOV_INSTRUMENT_ALL
203 bool "Instrument all code by default"
204 depends on KERNEL_KCOV
205 default y if KERNEL_KCOV
207 If you are doing generic system call fuzzing (like e.g. syzkaller),
208 then you will want to instrument the whole kernel and you should
209 say y here. If you are doing more targeted fuzzing (like e.g.
210 filesystem fuzzing with AFL) then you will want to enable coverage
211 for more specific subsets of files, and should say n here.
213 config KERNEL_TASKSTATS
214 bool "Compile the kernel with task resource/io statistics and accounting"
217 Enable the collection and publishing of task/io statistics and
218 accounting. Enable this option to enable i/o monitoring in system
223 config KERNEL_TASK_DELAY_ACCT
226 config KERNEL_TASK_IO_ACCOUNTING
229 config KERNEL_TASK_XACCT
234 config KERNEL_KALLSYMS
235 bool "Compile the kernel with symbol table information"
236 default y if !SMALL_FLASH
238 This will give you more information in stack traces from kernel oopses.
241 bool "Compile the kernel with tracing support"
242 depends on !TARGET_uml
245 config KERNEL_FTRACE_SYSCALLS
246 bool "Trace system calls"
247 depends on KERNEL_FTRACE
250 config KERNEL_ENABLE_DEFAULT_TRACERS
251 bool "Trace process context switches and events"
252 depends on KERNEL_FTRACE
255 config KERNEL_FUNCTION_TRACER
256 bool "Function tracer"
257 depends on KERNEL_FTRACE
260 config KERNEL_FUNCTION_GRAPH_TRACER
261 bool "Function graph tracer"
262 depends on KERNEL_FUNCTION_TRACER
265 config KERNEL_DYNAMIC_FTRACE
266 bool "Enable/disable function tracing dynamically"
267 depends on KERNEL_FUNCTION_TRACER
270 config KERNEL_FUNCTION_PROFILER
271 bool "Function profiler"
272 depends on KERNEL_FUNCTION_TRACER
275 config KERNEL_DEBUG_KERNEL
279 config KERNEL_DEBUG_INFO
280 bool "Compile the kernel with debug information"
281 default y if !SMALL_FLASH
282 select KERNEL_DEBUG_KERNEL
284 This will compile your kernel and modules with debug information.
286 config KERNEL_DEBUG_LL_UART_NONE
291 config KERNEL_DEBUG_LL
295 select KERNEL_DEBUG_LL_UART_NONE
297 ARM low level debugging.
299 config KERNEL_DYNAMIC_DEBUG
300 bool "Compile the kernel with dynamic printk"
301 select KERNEL_DEBUG_FS
304 Compiles debug level messages into the kernel, which would not
305 otherwise be available at runtime. These messages can then be
306 enabled/disabled based on various levels of scope - per source file,
307 function, module, format string, and line number. This mechanism
308 implicitly compiles in all pr_debug() and dev_dbg() calls, which
309 enlarges the kernel text size by about 2%.
311 config KERNEL_EARLY_PRINTK
312 bool "Compile the kernel with early printk"
313 default y if TARGET_bcm53xx
316 select KERNEL_DEBUG_KERNEL
317 select KERNEL_DEBUG_LL if arm
319 Compile the kernel with early printk support. This is only useful for
320 debugging purposes to send messages over the serial console in early boot.
321 Enable this to debug early boot problems.
323 config KERNEL_KPROBES
324 bool "Compile the kernel with kprobes support"
327 select KERNEL_PERF_EVENTS
329 Compiles the kernel with KPROBES support, which allows you to trap
330 at almost any kernel address and execute a callback function.
331 register_kprobe() establishes a probepoint and specifies the
332 callback. Kprobes is useful for kernel debugging, non-intrusive
333 instrumentation and testing.
334 If in doubt, say "N".
336 config KERNEL_KPROBE_EVENT
338 default y if KERNEL_KPROBES
340 config KERNEL_KPROBE_EVENTS
342 default y if KERNEL_KPROBES
345 bool "Compile the kernel with asynchronous IO support"
346 default y if !SMALL_FLASH
348 config KERNEL_FHANDLE
349 bool "Compile the kernel with support for fhandle syscalls"
350 default y if !SMALL_FLASH
352 config KERNEL_FANOTIFY
353 bool "Compile the kernel with modern file notification support"
354 default y if !SMALL_FLASH
356 config KERNEL_BLK_DEV_BSG
357 bool "Compile the kernel with SCSI generic v4 support for any block device"
360 config KERNEL_TRANSPARENT_HUGEPAGE
363 config KERNEL_HUGETLBFS
366 config KERNEL_HUGETLB_PAGE
367 bool "Compile the kernel with HugeTLB support"
368 select KERNEL_TRANSPARENT_HUGEPAGE
369 select KERNEL_HUGETLBFS
372 config KERNEL_MAGIC_SYSRQ
373 bool "Compile the kernel with SysRq support"
376 config KERNEL_DEBUG_PINCTRL
377 bool "Compile the kernel with pinctrl debugging"
378 select KERNEL_DEBUG_KERNEL
380 config KERNEL_DEBUG_GPIO
381 bool "Compile the kernel with gpio debugging"
382 select KERNEL_DEBUG_KERNEL
384 config KERNEL_COREDUMP
387 config KERNEL_ELF_CORE
388 bool "Enable process core dump support"
389 select KERNEL_COREDUMP
390 default y if !SMALL_FLASH
392 config KERNEL_PROVE_LOCKING
393 bool "Enable kernel lock checking"
394 select KERNEL_DEBUG_KERNEL
397 config KERNEL_LOCKUP_DETECTOR
398 bool "Compile the kernel with detect Hard and Soft Lockups"
399 depends on KERNEL_DEBUG_KERNEL
401 Say Y here to enable the kernel to act as a watchdog to detect
402 hard and soft lockups.
404 Softlockups are bugs that cause the kernel to loop in kernel
405 mode for more than 20 seconds, without giving other tasks a
406 chance to run. The current stack trace is displayed upon
407 detection and the system will stay locked up.
409 Hardlockups are bugs that cause the CPU to loop in kernel mode
410 for more than 10 seconds, without letting other interrupts have a
411 chance to run. The current stack trace is displayed upon detection
412 and the system will stay locked up.
414 The overhead should be minimal. A periodic hrtimer runs to
415 generate interrupts and kick the watchdog task every 4 seconds.
416 An NMI is generated every 10 seconds or so to check for hardlockups.
418 The frequency of hrtimer and NMI events and the soft and hard lockup
419 thresholds can be controlled through the sysctl watchdog_thresh.
421 config KERNEL_DETECT_HUNG_TASK
422 bool "Compile the kernel with detect Hung Tasks"
423 depends on KERNEL_DEBUG_KERNEL
424 default KERNEL_LOCKUP_DETECTOR
426 Say Y here to enable the kernel to detect "hung tasks",
427 which are bugs that cause the task to be stuck in
428 uninterruptible "D" state indefinitely.
430 When a hung task is detected, the kernel will print the
431 current stack trace (which you should report), but the
432 task will stay in uninterruptible state. If lockdep is
433 enabled then all held locks will also be reported. This
434 feature has negligible overhead.
436 config KERNEL_WQ_WATCHDOG
437 bool "Compile the kernel with detect Workqueue Stalls"
438 depends on KERNEL_DEBUG_KERNEL
440 Say Y here to enable stall detection on workqueues. If a
441 worker pool doesn't make forward progress on a pending work
442 item for over a given amount of time, 30s by default, a
443 warning message is printed along with dump of workqueue
444 state. This can be configured through kernel parameter
445 "workqueue.watchdog_thresh" and its sysfs counterpart.
447 config KERNEL_DEBUG_ATOMIC_SLEEP
448 bool "Compile the kernel with sleep inside atomic section checking"
449 depends on KERNEL_DEBUG_KERNEL
451 If you say Y here, various routines which may sleep will become very
452 noisy if they are called inside atomic sections: when a spinlock is
453 held, inside an rcu read side critical section, inside preempt disabled
454 sections, inside an interrupt, etc...
456 config KERNEL_DEBUG_VM
457 bool "Compile the kernel with debug VM"
458 depends on KERNEL_DEBUG_KERNEL
460 Enable this to turn on extended checks in the virtual-memory system
461 that may impact performance.
465 config KERNEL_PRINTK_TIME
466 bool "Enable printk timestamps"
469 config KERNEL_SLUB_DEBUG
472 config KERNEL_SLUB_DEBUG_ON
475 config KERNEL_SLABINFO
476 select KERNEL_SLUB_DEBUG
477 select KERNEL_SLUB_DEBUG_ON
478 bool "Enable /proc slab debug info"
480 config KERNEL_PROC_PAGE_MONITOR
481 bool "Enable /proc page monitoring"
487 bool "Enable kexec support"
489 config KERNEL_PROC_VMCORE
492 config KERNEL_PROC_KCORE
495 config KERNEL_CRASH_DUMP
496 depends on i386 || x86_64 || arm || armeb
498 select KERNEL_PROC_VMCORE
499 select KERNEL_PROC_KCORE
500 bool "Enable support for kexec crashdump"
504 bool "Enable rfkill support"
505 default RFKILL_SUPPORT
508 bool "Enable sparse check during kernel build"
511 config KERNEL_DEVTMPFS
512 bool "Compile the kernel with device tmpfs enabled"
515 devtmpfs is a simple, kernel-managed /dev filesystem. The kernel creates
516 devices nodes for all registered devices to simplify boot, but leaves more
517 complex tasks to userspace (e.g. udev).
521 config KERNEL_DEVTMPFS_MOUNT
522 bool "Automatically mount devtmpfs after root filesystem is mounted"
528 bool "Enable kernel access key retention support"
531 config KERNEL_PERSISTENT_KEYRINGS
532 bool "Enable kernel persistent keyrings"
533 depends on KERNEL_KEYS
536 config KERNEL_BIG_KEYS
537 bool "Enable large payload keys on kernel keyrings"
538 depends on KERNEL_KEYS
541 config KERNEL_ENCRYPTED_KEYS
542 tristate "Enable keys with encrypted payloads on kernel keyrings"
543 depends on KERNEL_KEYS
547 # CGROUP support symbols
550 config KERNEL_CGROUPS
551 bool "Enable kernel cgroups"
552 default y if !SMALL_FLASH
556 config KERNEL_CGROUP_DEBUG
557 bool "Example debug cgroup subsystem"
560 This option enables a simple cgroup subsystem that
561 exports useful debugging information about the cgroups
564 config KERNEL_FREEZER
567 config KERNEL_CGROUP_FREEZER
568 bool "legacy Freezer cgroup subsystem"
570 select KERNEL_FREEZER
572 Provides a way to freeze and unfreeze all tasks in a
574 (legacy cgroup1-only controller, in cgroup2 freezer
575 is integrated in the Memory controller)
577 config KERNEL_CGROUP_DEVICE
578 bool "legacy Device controller for cgroups"
581 Provides a cgroup implementing whitelists for devices which
582 a process in the cgroup can mknod or open.
583 (legacy cgroup1-only controller)
585 config KERNEL_CGROUP_HUGETLB
586 bool "HugeTLB controller"
587 default y if KERNEL_HUGETLB_PAGE
588 depends on KERNEL_HUGETLB_PAGE
590 config KERNEL_CGROUP_PIDS
591 bool "PIDs cgroup subsystem"
594 Provides enforcement of process number limits in the scope of a
597 config KERNEL_CGROUP_RDMA
598 bool "RDMA controller for cgroups"
601 config KERNEL_CGROUP_BPF
602 bool "Support for eBPF programs attached to cgroups"
605 config KERNEL_CPUSETS
606 bool "Cpuset support"
607 default y if !SMALL_FLASH
609 This option will let you create and manage CPUSETs which
610 allow dynamically partitioning a system into sets of CPUs and
611 Memory Nodes and assigning tasks to run only within those sets.
612 This is primarily useful on large SMP or NUMA systems.
614 config KERNEL_PROC_PID_CPUSET
615 bool "Include legacy /proc/<pid>/cpuset file"
617 depends on KERNEL_CPUSETS
619 config KERNEL_CGROUP_CPUACCT
620 bool "Simple CPU accounting cgroup subsystem"
621 default y if !SMALL_FLASH
623 Provides a simple Resource Controller for monitoring the
624 total CPU consumed by the tasks in a cgroup.
626 config KERNEL_RESOURCE_COUNTERS
627 bool "Resource counters"
628 default y if !SMALL_FLASH
630 This option enables controller independent resource accounting
631 infrastructure that works with cgroups.
633 config KERNEL_MM_OWNER
635 default y if KERNEL_MEMCG
638 bool "Memory Resource Controller for Control Groups"
639 default y if !SMALL_FLASH
640 select KERNEL_FREEZER
641 depends on KERNEL_RESOURCE_COUNTERS || !LINUX_3_18
643 Provides a memory resource controller that manages both anonymous
644 memory and page cache. (See Documentation/cgroups/memory.txt)
646 Note that setting this option increases fixed memory overhead
647 associated with each page of memory in the system. By this,
648 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
649 usage tracking struct at boot. Total amount of this is printed out
652 Only enable when you're ok with these tradeoffs and really
653 sure you need the memory resource controller. Even when you enable
654 this, you can set "cgroup_disable=memory" at your boot option to
655 disable memory resource controller and you can avoid overheads
656 (but lose benefits of memory resource controller).
658 This config option also selects MM_OWNER config option, which
659 could in turn add some fork/exit overhead.
661 config KERNEL_MEMCG_SWAP
662 bool "Memory Resource Controller Swap Extension"
663 default y if !SMALL_FLASH
664 depends on KERNEL_MEMCG
666 Add swap management feature to memory resource controller. When you
667 enable this, you can limit mem+swap usage per cgroup. In other words,
668 when you disable this, memory resource controller has no cares to
669 usage of swap...a process can exhaust all of the swap. This extension
670 is useful when you want to avoid exhaustion swap but this itself
671 adds more overheads and consumes memory for remembering information.
672 Especially if you use 32bit system or small memory system, please
673 be careful about enabling this. When memory resource controller
674 is disabled by boot option, this will be automatically disabled and
675 there will be no overhead from this. Even when you set this config=y,
676 if boot option "swapaccount=0" is set, swap will not be accounted.
677 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
678 size is 4096bytes, 512k per 1Gbytes of swap.
680 config KERNEL_MEMCG_SWAP_ENABLED
681 bool "Memory Resource Controller Swap Extension enabled by default"
683 depends on KERNEL_MEMCG_SWAP
685 Memory Resource Controller Swap Extension comes with its price in
686 a bigger memory consumption. General purpose distribution kernels
687 which want to enable the feature but keep it disabled by default
688 and let the user enable it by swapaccount boot command line
689 parameter should have this option unselected.
691 Those who want to have the feature enabled by default should
692 select this option (if, for some reason, they need to disable it,
693 then swapaccount=0 does the trick).
696 config KERNEL_MEMCG_KMEM
697 bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
698 default y if !SMALL_FLASH
699 depends on KERNEL_MEMCG
701 The Kernel Memory extension for Memory Resource Controller can limit
702 the amount of memory used by kernel objects in the system. Those are
703 fundamentally different from the entities handled by the standard
704 Memory Controller, which are page-based, and can be swapped. Users of
705 the kmem extension can use it to guarantee that no group of processes
706 will ever exhaust kernel resources alone.
708 config KERNEL_CGROUP_PERF
709 bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
710 select KERNEL_PERF_EVENTS
713 This option extends the per-cpu mode to restrict monitoring to
714 threads which belong to the cgroup specified and run on the
717 menuconfig KERNEL_CGROUP_SCHED
718 bool "Group CPU scheduler"
719 default y if !SMALL_FLASH
721 This feature lets CPU scheduler recognize task groups and control CPU
722 bandwidth allocation to such task groups. It uses cgroups to group
725 if KERNEL_CGROUP_SCHED
727 config KERNEL_FAIR_GROUP_SCHED
728 bool "Group scheduling for SCHED_OTHER"
729 default y if !SMALL_FLASH
731 config KERNEL_CFS_BANDWIDTH
732 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
734 depends on KERNEL_FAIR_GROUP_SCHED
736 This option allows users to define CPU bandwidth rates (limits) for
737 tasks running within the fair group scheduler. Groups with no limit
738 set are considered to be unconstrained and will run with no
740 See tip/Documentation/scheduler/sched-bwc.txt for more information.
742 config KERNEL_RT_GROUP_SCHED
743 bool "Group scheduling for SCHED_RR/FIFO"
744 default y if !SMALL_FLASH
746 This feature lets you explicitly allocate real CPU bandwidth
747 to task groups. If enabled, it will also make it impossible to
748 schedule realtime tasks for non-root users until you allocate
749 realtime bandwidth for them.
753 config KERNEL_BLK_CGROUP
754 bool "Block IO controller"
757 Generic block IO controller cgroup interface. This is the common
758 cgroup interface which should be used by various IO controlling
761 Currently, CFQ IO scheduler uses it to recognize task groups and
762 control disk bandwidth allocation (proportional time slice allocation)
763 to such task groups. It is also used by bio throttling logic in
764 block layer to implement upper limit in IO rates on a device.
766 This option only enables generic Block IO controller infrastructure.
767 One needs to also enable actual IO controlling logic/policy. For
768 enabling proportional weight division of disk bandwidth in CFQ, set
769 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
770 CONFIG_BLK_DEV_THROTTLING=y.
774 config KERNEL_CFQ_GROUP_IOSCHED
775 bool "Proportional weight of disk bandwidth in CFQ"
777 config KERNEL_BLK_DEV_THROTTLING
778 bool "Enable throttling policy"
779 default y if TARGET_bcm27xx
781 config KERNEL_BLK_DEV_THROTTLING_LOW
782 bool "Block throttling .low limit interface support (EXPERIMENTAL)"
783 depends on KERNEL_BLK_DEV_THROTTLING
786 config KERNEL_DEBUG_BLK_CGROUP
787 bool "Enable Block IO controller debugging"
789 depends on KERNEL_BLK_CGROUP
791 Enable some debugging help. Currently it exports additional stat
792 files in a cgroup which can be useful for debugging.
794 config KERNEL_NET_CLS_CGROUP
795 bool "legacy Control Group Classifier"
798 config KERNEL_CGROUP_NET_PRIO
799 bool "legacy Network priority cgroup"
805 # Namespace support symbols
808 config KERNEL_NAMESPACES
809 bool "Enable kernel namespaces"
810 default y if !SMALL_FLASH
818 In this namespace, tasks see different info provided
819 with the uname() system call.
825 In this namespace, tasks work with IPC ids which correspond to
826 different IPC objects in different namespaces.
828 config KERNEL_USER_NS
829 bool "User namespace (EXPERIMENTAL)"
832 This allows containers, i.e. vservers, to use user namespaces
833 to provide different user info for different servers.
836 bool "PID Namespaces"
839 Support process id namespaces. This allows having multiple
840 processes with the same pid as long as they are in different
841 pid namespaces. This is a building block of containers.
844 bool "Network namespace"
847 Allow user space to create what appear to be multiple instances
848 of the network stack.
852 config KERNEL_DEVPTS_MULTIPLE_INSTANCES
853 bool "Support multiple instances of devpts"
854 default y if !SMALL_FLASH
856 Enable support for multiple instances of devpts filesystem.
857 If you want to have isolated PTY namespaces (eg: in containers),
858 say Y here. Otherwise, say N. If enabled, each mount of devpts
859 filesystem with the '-o newinstance' option will create an
860 independent PTY namespace.
862 config KERNEL_POSIX_MQUEUE
863 bool "POSIX Message Queues"
864 default y if !SMALL_FLASH
866 POSIX variant of message queues is a part of IPC. In POSIX message
867 queues every message has a priority which decides about succession
868 of receiving it by a process. If you want to compile and run
869 programs written e.g. for Solaris with use of its POSIX message
870 queues (functions mq_*) say Y here.
872 POSIX message queues are visible as a filesystem called 'mqueue'
873 and can be mounted somewhere if you want to do filesystem
874 operations on message queues.
877 config KERNEL_SECCOMP_FILTER
879 default y if !SMALL_FLASH
881 config KERNEL_SECCOMP
882 bool "Enable seccomp support"
883 depends on !(TARGET_uml)
884 select KERNEL_SECCOMP_FILTER
885 default y if !SMALL_FLASH
887 Build kernel with support for seccomp.
893 config KERNEL_IP_MROUTE
894 bool "Enable IPv4 multicast routing"
897 Multicast routing requires a multicast routing daemon in
898 addition to kernel support.
909 config KERNEL_IPV6_MULTIPLE_TABLES
912 config KERNEL_IPV6_SUBTREES
915 config KERNEL_IPV6_MROUTE
916 bool "Enable IPv6 multicast routing"
919 Multicast routing requires a multicast routing daemon in
920 addition to kernel support.
922 config KERNEL_IPV6_PIMSM_V2
928 # NFS related symbols
931 bool "Compile the kernel with rootfs on NFS"
933 If you want to make your kernel boot off a NFS server as root
934 filesystem, select Y here.
938 config KERNEL_IP_PNP_DHCP
941 config KERNEL_IP_PNP_BOOTP
944 config KERNEL_IP_PNP_RARP
956 config KERNEL_ROOT_NFS
961 menu "Filesystem ACL and attr support options"
962 config USE_FS_ACL_ATTR
963 bool "Use filesystem ACL and attr support by default"
966 Make using ACLs (e.g. POSIX ACL, NFSv4 ACL) the default
967 for kernel and packages, except tmpfs, flash filesystems,
968 and old NFS. Also enable userspace extended attribute support
969 by default. (OpenWrt already has an expection it will be
970 present in the kernel).
972 config KERNEL_FS_POSIX_ACL
973 bool "Enable POSIX ACL support"
974 default y if USE_FS_ACL_ATTR
976 config KERNEL_BTRFS_FS_POSIX_ACL
977 bool "Enable POSIX ACL for BtrFS Filesystems"
978 select KERNEL_FS_POSIX_ACL
979 default y if USE_FS_ACL_ATTR
981 config KERNEL_EXT4_FS_POSIX_ACL
982 bool "Enable POSIX ACL for Ext4 Filesystems"
983 select KERNEL_FS_POSIX_ACL
984 default y if USE_FS_ACL_ATTR
986 config KERNEL_F2FS_FS_POSIX_ACL
987 bool "Enable POSIX ACL for F2FS Filesystems"
988 select KERNEL_FS_POSIX_ACL
991 config KERNEL_JFFS2_FS_POSIX_ACL
992 bool "Enable POSIX ACL for JFFS2 Filesystems"
993 select KERNEL_FS_POSIX_ACL
996 config KERNEL_TMPFS_POSIX_ACL
997 bool "Enable POSIX ACL for TMPFS Filesystems"
998 select KERNEL_FS_POSIX_ACL
1001 config KERNEL_CIFS_ACL
1002 bool "Enable CIFS ACLs"
1003 select KERNEL_FS_POSIX_ACL
1004 default y if USE_FS_ACL_ATTR
1006 config KERNEL_HFS_FS_POSIX_ACL
1007 bool "Enable POSIX ACL for HFS Filesystems"
1008 select KERNEL_FS_POSIX_ACL
1009 default y if USE_FS_ACL_ATTR
1011 config KERNEL_HFSPLUS_FS_POSIX_ACL
1012 bool "Enable POSIX ACL for HFS+ Filesystems"
1013 select KERNEL_FS_POSIX_ACL
1014 default y if USE_FS_ACL_ATTR
1016 config KERNEL_NFS_ACL_SUPPORT
1017 bool "Enable ACLs for NFS"
1018 default y if USE_FS_ACL_ATTR
1020 config KERNEL_NFS_V3_ACL_SUPPORT
1021 bool "Enable ACLs for NFSv3"
1024 config KERNEL_NFSD_V2_ACL_SUPPORT
1025 bool "Enable ACLs for NFSDv2"
1028 config KERNEL_NFSD_V3_ACL_SUPPORT
1029 bool "Enable ACLs for NFSDv3"
1032 config KERNEL_REISER_FS_POSIX_ACL
1033 bool "Enable POSIX ACLs for ReiserFS"
1034 select KERNEL_FS_POSIX_ACL
1035 default y if USE_FS_ACL_ATTR
1037 config KERNEL_XFS_POSIX_ACL
1038 bool "Enable POSIX ACLs for XFS"
1039 select KERNEL_FS_POSIX_ACL
1040 default y if USE_FS_ACL_ATTR
1042 config KERNEL_JFS_POSIX_ACL
1043 bool "Enable POSIX ACLs for JFS"
1044 select KERNEL_FS_POSIX_ACL
1045 default y if USE_FS_ACL_ATTR
1049 config KERNEL_DEVMEM
1050 bool "/dev/mem virtual device support"
1052 Say Y here if you want to support the /dev/mem device.
1053 The /dev/mem device is used to access areas of physical
1056 config KERNEL_DEVKMEM
1057 bool "/dev/kmem virtual device support"
1059 Say Y here if you want to support the /dev/kmem device. The
1060 /dev/kmem device is rarely used, but can be used for certain
1061 kind of kernel debugging operations.
1063 config KERNEL_SQUASHFS_FRAGMENT_CACHE_SIZE
1064 int "Number of squashfs fragments cached"
1065 default 2 if (SMALL_FLASH && !LOW_MEMORY_FOOTPRINT)
1069 # compile optimiziation setting
1072 prompt "Compiler optimization level"
1073 default KERNEL_CC_OPTIMIZE_FOR_SIZE if SMALL_FLASH
1075 config KERNEL_CC_OPTIMIZE_FOR_PERFORMANCE
1076 bool "Optimize for performance"
1078 This is the default optimization level for the kernel, building
1079 with the "-O2" compiler flag for best performance and most
1080 helpful compile-time warnings.
1082 config KERNEL_CC_OPTIMIZE_FOR_SIZE
1083 bool "Optimize for size"
1085 Enabling this option will pass "-Os" instead of "-O2" to
1086 your compiler resulting in a smaller kernel.