OpenWrt – Rev 1
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# Copyright (C) 2006-2014 OpenWrt.org
#
# This is free software, licensed under the GNU General Public License v2.
# See /LICENSE for more information.
#
config KERNEL_BUILD_USER
string "Custom Kernel Build User Name"
default ""
help
Sets the Kernel build user string, which for example will be returned
by 'uname -a' on running systems.
If not set, uses system user at build time.
config KERNEL_BUILD_DOMAIN
string "Custom Kernel Build Domain Name"
default ""
help
Sets the Kernel build domain string, which for example will be
returned by 'uname -a' on running systems.
If not set, uses system hostname at build time.
config KERNEL_PRINTK
bool "Enable support for printk"
default y
config KERNEL_CRASHLOG
bool "Crash logging"
depends on !(arm || powerpc || sparc || TARGET_uml || i386 || x86_64)
default y
config KERNEL_SWAP
bool "Support for paging of anonymous memory (swap)"
default y if !SMALL_FLASH
config KERNEL_DEBUG_FS
bool "Compile the kernel with debug filesystem enabled"
default y
help
debugfs is a virtual file system that kernel developers use to put
debugging files into. Enable this option to be able to read and
write to these files. Many common debugging facilities, such as
ftrace, require the existence of debugfs.
config KERNEL_MIPS_FPU_EMULATOR
bool "Compile the kernel with MIPS FPU Emulator"
default y if TARGET_pistachio
depends on (mips || mipsel || mips64 || mips64el)
config KERNEL_ARM_PMU
bool
default n
depends on (arm || aarch64)
config KERNEL_PERF_EVENTS
bool "Compile the kernel with performance events and counters"
default n
select KERNEL_ARM_PMU if (arm || aarch64)
config KERNEL_PROFILING
bool "Compile the kernel with profiling enabled"
default n
select KERNEL_PERF_EVENTS
help
Enable the extended profiling support mechanisms used by profilers such
as OProfile.
config KERNEL_TASKSTATS
bool "Compile the kernel with task resource/io statistics and accounting"
default n
help
Enable the collection and publishing of task/io statistics and
accounting. Enable this option to enable i/o monitoring in system
monitors.
if KERNEL_TASKSTATS
config KERNEL_TASK_DELAY_ACCT
def_bool y
config KERNEL_TASK_IO_ACCOUNTING
def_bool y
config KERNEL_TASK_XACCT
def_bool y
endif
config KERNEL_KALLSYMS
bool "Compile the kernel with symbol table information"
default y if !SMALL_FLASH
help
This will give you more information in stack traces from kernel oopses.
config KERNEL_FTRACE
bool "Compile the kernel with tracing support"
depends on !TARGET_uml
default n
config KERNEL_FTRACE_SYSCALLS
bool "Trace system calls"
depends on KERNEL_FTRACE
default n
config KERNEL_ENABLE_DEFAULT_TRACERS
bool "Trace process context switches and events"
depends on KERNEL_FTRACE
default n
config KERNEL_FUNCTION_TRACER
bool "Function tracer"
depends on KERNEL_FTRACE
default n
config KERNEL_FUNCTION_GRAPH_TRACER
bool "Function graph tracer"
depends on KERNEL_FUNCTION_TRACER
default n
config KERNEL_DYNAMIC_FTRACE
bool "Enable/disable function tracing dynamically"
depends on KERNEL_FUNCTION_TRACER
default n
config KERNEL_FUNCTION_PROFILER
bool "Function profiler"
depends on KERNEL_FUNCTION_TRACER
default n
config KERNEL_DEBUG_KERNEL
bool
default n
config KERNEL_DEBUG_INFO
bool "Compile the kernel with debug information"
default y if !SMALL_FLASH
select KERNEL_DEBUG_KERNEL
help
This will compile your kernel and modules with debug information.
config KERNEL_DEBUG_LL_UART_NONE
bool
default n
depends on arm
config KERNEL_DEBUG_LL
bool
default n
depends on arm
select KERNEL_DEBUG_LL_UART_NONE
help
ARM low level debugging.
config KERNEL_DYNAMIC_DEBUG
bool "Compile the kernel with dynamic printk"
select KERNEL_DEBUG_FS
default n
help
Compiles debug level messages into the kernel, which would not
otherwise be available at runtime. These messages can then be
enabled/disabled based on various levels of scope - per source file,
function, module, format string, and line number. This mechanism
implicitly compiles in all pr_debug() and dev_dbg() calls, which
enlarges the kernel text size by about 2%.
config KERNEL_EARLY_PRINTK
bool "Compile the kernel with early printk"
default y if TARGET_bcm53xx
default n
depends on arm
select KERNEL_DEBUG_KERNEL
select KERNEL_DEBUG_LL if arm
help
Compile the kernel with early printk support. This is only useful for
debugging purposes to send messages over the serial console in early boot.
Enable this to debug early boot problems.
config KERNEL_KPROBES
bool "Compile the kernel with kprobes support"
default n
select KERNEL_FTRACE
select KERNEL_PERF_EVENTS
help
Compiles the kernel with KPROBES support, which allows you to trap
at almost any kernel address and execute a callback function.
register_kprobe() establishes a probepoint and specifies the
callback. Kprobes is useful for kernel debugging, non-intrusive
instrumentation and testing.
If in doubt, say "N".
config KERNEL_KPROBE_EVENT
bool
default y if KERNEL_KPROBES
config KERNEL_AIO
bool "Compile the kernel with asynchronous IO support"
default n
config KERNEL_FHANDLE
bool "Compile the kernel with support for fhandle syscalls"
default n
config KERNEL_FANOTIFY
bool "Compile the kernel with modern file notification support"
default n
config KERNEL_BLK_DEV_BSG
bool "Compile the kernel with SCSI generic v4 support for any block device"
default n
config KERNEL_MAGIC_SYSRQ
bool "Compile the kernel with SysRq support"
default y
config KERNEL_DEBUG_PINCTRL
bool "Compile the kernel with pinctrl debugging"
select KERNEL_DEBUG_KERNEL
config KERNEL_DEBUG_GPIO
bool "Compile the kernel with gpio debugging"
select KERNEL_DEBUG_KERNEL
config KERNEL_COREDUMP
bool
config KERNEL_ELF_CORE
bool "Enable process core dump support"
select KERNEL_COREDUMP
default y if !SMALL_FLASH
config KERNEL_PROVE_LOCKING
bool "Enable kernel lock checking"
select KERNEL_DEBUG_KERNEL
default n
config KERNEL_PRINTK_TIME
bool "Enable printk timestamps"
default y
config KERNEL_SLUB_DEBUG
bool
config KERNEL_SLUB_DEBUG_ON
bool
config KERNEL_SLABINFO
select KERNEL_SLUB_DEBUG
select KERNEL_SLUB_DEBUG_ON
bool "Enable /proc slab debug info"
config KERNEL_PROC_PAGE_MONITOR
bool "Enable /proc page monitoring"
config KERNEL_RELAY
bool
config KERNEL_KEXEC
bool "Enable kexec support"
config KERNEL_PROC_VMCORE
bool
config KERNEL_CRASH_DUMP
depends on i386 || x86_64 || arm || armeb
select KERNEL_KEXEC
select KERNEL_PROC_VMCORE
bool "Enable support for kexec crashdump"
default y
config USE_RFKILL
bool "Enable rfkill support"
default RFKILL_SUPPORT
config USE_SPARSE
bool "Enable sparse check during kernel build"
default n
config KERNEL_DEVTMPFS
bool "Compile the kernel with device tmpfs enabled"
default n
help
devtmpfs is a simple, kernel-managed /dev filesystem. The kernel creates
devices nodes for all registered devices to simplify boot, but leaves more
complex tasks to userspace (e.g. udev).
if KERNEL_DEVTMPFS
config KERNEL_DEVTMPFS_MOUNT
bool "Automatically mount devtmpfs after root filesystem is mounted"
default n
endif
config KERNEL_KEYS
bool "Enable kernel access key retention support"
default n
config KERNEL_PERSISTENT_KEYRINGS
bool "Enable kernel persistent keyrings"
depends on KERNEL_KEYS
default n
config KERNEL_BIG_KEYS
bool "Enable large payload keys on kernel keyrings"
depends on KERNEL_KEYS
default n
config KERNEL_ENCRYPTED_KEYS
tristate "Enable keys with encrypted payloads on kernel keyrings"
depends on KERNEL_KEYS
default n
#
# CGROUP support symbols
#
config KERNEL_CGROUPS
bool "Enable kernel cgroups"
default n
if KERNEL_CGROUPS
config KERNEL_CGROUP_DEBUG
bool "Example debug cgroup subsystem"
default n
help
This option enables a simple cgroup subsystem that
exports useful debugging information about the cgroups
framework.
config KERNEL_FREEZER
bool
default y if KERNEL_CGROUP_FREEZER
config KERNEL_CGROUP_FREEZER
bool "Freezer cgroup subsystem"
default y
help
Provides a way to freeze and unfreeze all tasks in a
cgroup.
config KERNEL_CGROUP_DEVICE
bool "Device controller for cgroups"
default y
help
Provides a cgroup implementing whitelists for devices which
a process in the cgroup can mknod or open.
config KERNEL_CGROUP_PIDS
bool "PIDs cgroup subsystem"
default y
help
Provides enforcement of process number limits in the scope of a
cgroup.
config KERNEL_CPUSETS
bool "Cpuset support"
default n
help
This option will let you create and manage CPUSETs which
allow dynamically partitioning a system into sets of CPUs and
Memory Nodes and assigning tasks to run only within those sets.
This is primarily useful on large SMP or NUMA systems.
config KERNEL_PROC_PID_CPUSET
bool "Include legacy /proc/<pid>/cpuset file"
default n
depends on KERNEL_CPUSETS
config KERNEL_CGROUP_CPUACCT
bool "Simple CPU accounting cgroup subsystem"
default n
help
Provides a simple Resource Controller for monitoring the
total CPU consumed by the tasks in a cgroup.
config KERNEL_RESOURCE_COUNTERS
bool "Resource counters"
default n
help
This option enables controller independent resource accounting
infrastructure that works with cgroups.
config KERNEL_MM_OWNER
bool
default y if KERNEL_MEMCG
config KERNEL_MEMCG
bool "Memory Resource Controller for Control Groups"
default n
depends on KERNEL_RESOURCE_COUNTERS || !LINUX_3_18
help
Provides a memory resource controller that manages both anonymous
memory and page cache. (See Documentation/cgroups/memory.txt)
Note that setting this option increases fixed memory overhead
associated with each page of memory in the system. By this,
20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
usage tracking struct at boot. Total amount of this is printed out
at boot.
Only enable when you're ok with these tradeoffs and really
sure you need the memory resource controller. Even when you enable
this, you can set "cgroup_disable=memory" at your boot option to
disable memory resource controller and you can avoid overheads
(but lose benefits of memory resource controller).
This config option also selects MM_OWNER config option, which
could in turn add some fork/exit overhead.
config KERNEL_MEMCG_SWAP
bool "Memory Resource Controller Swap Extension"
default n
depends on KERNEL_MEMCG
help
Add swap management feature to memory resource controller. When you
enable this, you can limit mem+swap usage per cgroup. In other words,
when you disable this, memory resource controller has no cares to
usage of swap...a process can exhaust all of the swap. This extension
is useful when you want to avoid exhaustion swap but this itself
adds more overheads and consumes memory for remembering information.
Especially if you use 32bit system or small memory system, please
be careful about enabling this. When memory resource controller
is disabled by boot option, this will be automatically disabled and
there will be no overhead from this. Even when you set this config=y,
if boot option "swapaccount=0" is set, swap will not be accounted.
Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
size is 4096bytes, 512k per 1Gbytes of swap.
config KERNEL_MEMCG_SWAP_ENABLED
bool "Memory Resource Controller Swap Extension enabled by default"
default n
depends on KERNEL_MEMCG_SWAP
help
Memory Resource Controller Swap Extension comes with its price in
a bigger memory consumption. General purpose distribution kernels
which want to enable the feature but keep it disabled by default
and let the user enable it by swapaccount boot command line
parameter should have this option unselected.
Those who want to have the feature enabled by default should
select this option (if, for some reason, they need to disable it,
then swapaccount=0 does the trick).
config KERNEL_MEMCG_KMEM
bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
default n
depends on KERNEL_MEMCG
help
The Kernel Memory extension for Memory Resource Controller can limit
the amount of memory used by kernel objects in the system. Those are
fundamentally different from the entities handled by the standard
Memory Controller, which are page-based, and can be swapped. Users of
the kmem extension can use it to guarantee that no group of processes
will ever exhaust kernel resources alone.
config KERNEL_CGROUP_PERF
bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
select KERNEL_PERF_EVENTS
default n
help
This option extends the per-cpu mode to restrict monitoring to
threads which belong to the cgroup specified and run on the
designated cpu.
menuconfig KERNEL_CGROUP_SCHED
bool "Group CPU scheduler"
default n
help
This feature lets CPU scheduler recognize task groups and control CPU
bandwidth allocation to such task groups. It uses cgroups to group
tasks.
if KERNEL_CGROUP_SCHED
config KERNEL_FAIR_GROUP_SCHED
bool "Group scheduling for SCHED_OTHER"
default n
config KERNEL_CFS_BANDWIDTH
bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
default n
depends on KERNEL_FAIR_GROUP_SCHED
help
This option allows users to define CPU bandwidth rates (limits) for
tasks running within the fair group scheduler. Groups with no limit
set are considered to be unconstrained and will run with no
restriction.
See tip/Documentation/scheduler/sched-bwc.txt for more information.
config KERNEL_RT_GROUP_SCHED
bool "Group scheduling for SCHED_RR/FIFO"
default n
help
This feature lets you explicitly allocate real CPU bandwidth
to task groups. If enabled, it will also make it impossible to
schedule realtime tasks for non-root users until you allocate
realtime bandwidth for them.
endif
config KERNEL_BLK_CGROUP
bool "Block IO controller"
default y
help
Generic block IO controller cgroup interface. This is the common
cgroup interface which should be used by various IO controlling
policies.
Currently, CFQ IO scheduler uses it to recognize task groups and
control disk bandwidth allocation (proportional time slice allocation)
to such task groups. It is also used by bio throttling logic in
block layer to implement upper limit in IO rates on a device.
This option only enables generic Block IO controller infrastructure.
One needs to also enable actual IO controlling logic/policy. For
enabling proportional weight division of disk bandwidth in CFQ, set
CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
CONFIG_BLK_DEV_THROTTLING=y.
if KERNEL_BLK_CGROUP
config KERNEL_CFQ_GROUP_IOSCHED
bool "Proportional weight of disk bandwidth in CFQ"
config KERNEL_BLK_DEV_THROTTLING
bool "Enable throttling policy"
default y if TARGET_brcm2708
config KERNEL_BLK_DEV_THROTTLING_LOW
bool "Block throttling .low limit interface support (EXPERIMENTAL)"
depends on KERNEL_BLK_DEV_THROTTLING
endif
config KERNEL_DEBUG_BLK_CGROUP
bool "Enable Block IO controller debugging"
default n
depends on KERNEL_BLK_CGROUP
help
Enable some debugging help. Currently it exports additional stat
files in a cgroup which can be useful for debugging.
config KERNEL_NET_CLS_CGROUP
bool "Control Group Classifier"
default y
config KERNEL_NETPRIO_CGROUP
bool "Network priority cgroup"
default y
endif
#
# Namespace support symbols
#
config KERNEL_NAMESPACES
bool "Enable kernel namespaces"
default n
if KERNEL_NAMESPACES
config KERNEL_UTS_NS
bool "UTS namespace"
default y
help
In this namespace, tasks see different info provided
with the uname() system call.
config KERNEL_IPC_NS
bool "IPC namespace"
default y
help
In this namespace, tasks work with IPC ids which correspond to
different IPC objects in different namespaces.
config KERNEL_USER_NS
bool "User namespace (EXPERIMENTAL)"
default y
help
This allows containers, i.e. vservers, to use user namespaces
to provide different user info for different servers.
config KERNEL_PID_NS
bool "PID Namespaces"
default y
help
Support process id namespaces. This allows having multiple
processes with the same pid as long as they are in different
pid namespaces. This is a building block of containers.
config KERNEL_NET_NS
bool "Network namespace"
default y
help
Allow user space to create what appear to be multiple instances
of the network stack.
endif
#
# LXC related symbols
#
config KERNEL_LXC_MISC
bool "Enable miscellaneous LXC related options"
default n
if KERNEL_LXC_MISC
config KERNEL_DEVPTS_MULTIPLE_INSTANCES
bool "Support multiple instances of devpts"
default y
help
Enable support for multiple instances of devpts filesystem.
If you want to have isolated PTY namespaces (eg: in containers),
say Y here. Otherwise, say N. If enabled, each mount of devpts
filesystem with the '-o newinstance' option will create an
independent PTY namespace.
config KERNEL_POSIX_MQUEUE
bool "POSIX Message Queues"
default y
help
POSIX variant of message queues is a part of IPC. In POSIX message
queues every message has a priority which decides about succession
of receiving it by a process. If you want to compile and run
programs written e.g. for Solaris with use of its POSIX message
queues (functions mq_*) say Y here.
POSIX message queues are visible as a filesystem called 'mqueue'
and can be mounted somewhere if you want to do filesystem
operations on message queues.
endif
config KERNEL_SECCOMP_FILTER
bool
default n
config KERNEL_SECCOMP
bool "Enable seccomp support"
depends on !(TARGET_uml)
select KERNEL_SECCOMP_FILTER
default n
help
Build kernel with support for seccomp.
#
# IPv4 configuration
#
config KERNEL_IP_MROUTE
bool "Enable IPv4 multicast routing"
default y
help
Multicast routing requires a multicast routing daemon in
addition to kernel support.
#
# IPv6 configuration
#
config KERNEL_IPV6
def_bool IPV6
if KERNEL_IPV6
config KERNEL_IPV6_MULTIPLE_TABLES
def_bool y
config KERNEL_IPV6_SUBTREES
def_bool y
config KERNEL_IPV6_MROUTE
bool "Enable IPv6 multicast routing"
default y
help
Multicast routing requires a multicast routing daemon in
addition to kernel support.
config KERNEL_IPV6_PIMSM_V2
def_bool n
endif
#
# NFS related symbols
#
config KERNEL_IP_PNP
bool "Compile the kernel with rootfs on NFS"
help
If you want to make your kernel boot off a NFS server as root
filesystem, select Y here.
if KERNEL_IP_PNP
config KERNEL_IP_PNP_DHCP
def_bool y
config KERNEL_IP_PNP_BOOTP
def_bool n
config KERNEL_IP_PNP_RARP
def_bool n
config KERNEL_NFS_FS
def_bool y
config KERNEL_NFS_V2
def_bool y
config KERNEL_NFS_V3
def_bool y
config KERNEL_ROOT_NFS
def_bool y
endif
menu "Filesystem ACL and attr support options"
config USE_FS_ACL_ATTR
bool "Use filesystem ACL and attr support by default"
default n
help
Make using ACLs (e.g. POSIX ACL, NFSv4 ACL) the default
for kernel and packages, except tmpfs, flash filesystems,
and old NFS. Also enable userspace extended attribute support
by default. (OpenWrt already has an expection it will be
present in the kernel).
config KERNEL_FS_POSIX_ACL
bool "Enable POSIX ACL support"
default y if USE_FS_ACL_ATTR
config KERNEL_BTRFS_FS_POSIX_ACL
bool "Enable POSIX ACL for BtrFS Filesystems"
select KERNEL_FS_POSIX_ACL
default y if USE_FS_ACL_ATTR
config KERNEL_EXT4_FS_POSIX_ACL
bool "Enable POSIX ACL for Ext4 Filesystems"
select KERNEL_FS_POSIX_ACL
default y if USE_FS_ACL_ATTR
config KERNEL_F2FS_FS_POSIX_ACL
bool "Enable POSIX ACL for F2FS Filesystems"
select KERNEL_FS_POSIX_ACL
default n
config KERNEL_JFFS2_FS_POSIX_ACL
bool "Enable POSIX ACL for JFFS2 Filesystems"
select KERNEL_FS_POSIX_ACL
default n
config KERNEL_TMPFS_POSIX_ACL
bool "Enable POSIX ACL for TMPFS Filesystems"
select KERNEL_FS_POSIX_ACL
default n
config KERNEL_CIFS_ACL
bool "Enable CIFS ACLs"
select KERNEL_FS_POSIX_ACL
default y if USE_FS_ACL_ATTR
config KERNEL_HFS_FS_POSIX_ACL
bool "Enable POSIX ACL for HFS Filesystems"
select KERNEL_FS_POSIX_ACL
default y if USE_FS_ACL_ATTR
config KERNEL_HFSPLUG_FS_POSIX_ACL
bool "Enable POSIX ACL for HFS+ Filesystems"
select KERNEL_FS_POSIX_ACL
default y if USE_FS_ACL_ATTR
config KERNEL_NFS_ACL_SUPPORT
bool "Enable ACLs for NFS"
default y if USE_FS_ACL_ATTR
config KERNEL_NFS_V3_ACL_SUPPORT
bool "Enable ACLs for NFSv3"
default n
config KERNEL_NFSD_V2_ACL_SUPPORT
bool "Enable ACLs for NFSDv2"
default n
config KERNEL_NFSD_V3_ACL_SUPPORT
bool "Enable ACLs for NFSDv3"
default n
config KERNEL_REISER_FS_POSIX_ACL
bool "Enable POSIX ACLs for ReiserFS"
select KERNEL_FS_POSIX_ACL
default y if USE_FS_ACL_ATTR
config KERNEL_XFS_POSIX_ACL
bool "Enable POSIX ACLs for XFS"
select KERNEL_FS_POSIX_ACL
default y if USE_FS_ACL_ATTR
config KERNEL_JFS_POSIX_ACL
bool "Enable POSIX ACLs for JFS"
select KERNEL_FS_POSIX_ACL
default y if USE_FS_ACL_ATTR
endmenu
config KERNEL_DEVMEM
bool "/dev/mem virtual device support"
help
Say Y here if you want to support the /dev/mem device.
The /dev/mem device is used to access areas of physical
memory.
config KERNEL_DEVKMEM
bool "/dev/kmem virtual device support"
help
Say Y here if you want to support the /dev/kmem device. The
/dev/kmem device is rarely used, but can be used for certain
kind of kernel debugging operations.
config KERNEL_SQUASHFS_FRAGMENT_CACHE_SIZE
int "Number of squashfs fragments cached"
default 2 if (SMALL_FLASH && !LOW_MEMORY_FOOTPRINT)
default 3
#
# compile optimiziation setting
#
choice
prompt "Compiler optimization level"
default KERNEL_CC_OPTIMIZE_FOR_SIZE if SMALL_FLASH
config KERNEL_CC_OPTIMIZE_FOR_PERFORMANCE
bool "Optimize for performance"
help
This is the default optimization level for the kernel, building
with the "-O2" compiler flag for best performance and most
helpful compile-time warnings.
config KERNEL_CC_OPTIMIZE_FOR_SIZE
bool "Optimize for size"
help
Enabling this option will pass "-Os" instead of "-O2" to
your compiler resulting in a smaller kernel.
endchoice