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- # SPDX-License-Identifier: GPL-2.0-only
- #
- # Copyright (C) 2006-2014 OpenWrt.org
- config KERNEL_BUILD_USER
- string "Custom Kernel Build User Name"
- default "builder" if BUILDBOT
- 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 "buildhost" if BUILDBOT
- 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_SWAP
- bool "Support for paging of anonymous memory (swap)"
- default y if !SMALL_FLASH
- config KERNEL_PROC_STRIPPED
- bool "Strip non-essential /proc functionality to reduce code size"
- 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_FP_SUPPORT
- bool
- default y if TARGET_pistachio
- config KERNEL_ARM_PMU
- bool
- default y if TARGET_armsr_armv8
- depends on (arm || aarch64)
- config KERNEL_X86_VSYSCALL_EMULATION
- bool "Enable vsyscall emulation"
- depends on x86_64
- help
- This enables emulation of the legacy vsyscall page. Disabling
- it is roughly equivalent to booting with vsyscall=none, except
- that it will also disable the helpful warning if a program
- tries to use a vsyscall. With this option set to N, offending
- programs will just segfault, citing addresses of the form
- 0xffffffffff600?00.
- This option is required by many programs built before 2013, and
- care should be used even with newer programs if set to N.
- Disabling this option saves about 7K of kernel size and
- possibly 4K of additional runtime pagetable memory.
- config KERNEL_PERF_EVENTS
- bool "Compile the kernel with performance events and counters"
- select KERNEL_ARM_PMU if (arm || aarch64)
- config KERNEL_PROFILING
- bool "Compile the kernel with profiling enabled"
- select KERNEL_PERF_EVENTS
- help
- Enable the extended profiling support mechanisms used by profilers such
- as OProfile.
- config KERNEL_RPI_AXIPERF
- bool "Compile the kernel with RaspberryPi AXI Performance monitors"
- default y
- depends on KERNEL_PERF_EVENTS && TARGET_bcm27xx
- config KERNEL_UBSAN
- bool "Compile the kernel with undefined behaviour sanity checker"
- help
- This option enables undefined behaviour sanity checker
- Compile-time instrumentation is used to detect various undefined
- behaviours in runtime. Various types of checks may be enabled
- via boot parameter ubsan_handle
- (see: Documentation/dev-tools/ubsan.rst).
- config KERNEL_UBSAN_SANITIZE_ALL
- bool "Enable instrumentation for the entire kernel"
- depends on KERNEL_UBSAN
- default y
- help
- This option activates instrumentation for the entire kernel.
- If you don't enable this option, you have to explicitly specify
- UBSAN_SANITIZE := y for the files/directories you want to check for UB.
- Enabling this option will get kernel image size increased
- significantly.
- config KERNEL_UBSAN_ALIGNMENT
- bool "Enable checking of pointers alignment"
- depends on KERNEL_UBSAN
- help
- This option enables detection of unaligned memory accesses.
- Enabling this option on architectures that support unaligned
- accesses may produce a lot of false positives.
- config KERNEL_UBSAN_BOUNDS
- bool "Perform array index bounds checking"
- depends on KERNEL_UBSAN
- help
- This option enables detection of directly indexed out of bounds array
- accesses, where the array size is known at compile time. Note that
- this does not protect array overflows via bad calls to the
- {str,mem}*cpy() family of functions (that is addressed by
- FORTIFY_SOURCE).
- config KERNEL_UBSAN_NULL
- bool "Enable checking of null pointers"
- depends on KERNEL_UBSAN
- help
- This option enables detection of memory accesses via a
- null pointer.
- config KERNEL_UBSAN_TRAP
- bool "On Sanitizer warnings, abort the running kernel code"
- depends on KERNEL_UBSAN
- help
- Building kernels with Sanitizer features enabled tends to grow the
- kernel size by around 5%, due to adding all the debugging text on
- failure paths. To avoid this, Sanitizer instrumentation can just
- issue a trap. This reduces the kernel size overhead but turns all
- warnings (including potentially harmless conditions) into full
- exceptions that abort the running kernel code (regardless of context,
- locks held, etc), which may destabilize the system. For some system
- builders this is an acceptable trade-off.
- config KERNEL_KASAN
- bool "Compile the kernel with KASan: runtime memory debugger"
- select KERNEL_SLUB_DEBUG
- depends on (x86_64 || aarch64)
- help
- Enables kernel address sanitizer - runtime memory debugger,
- designed to find out-of-bounds accesses and use-after-free bugs.
- This is strictly a debugging feature and it requires a gcc version
- of 4.9.2 or later. Detection of out of bounds accesses to stack or
- global variables requires gcc 5.0 or later.
- This feature consumes about 1/8 of available memory and brings about
- ~x3 performance slowdown.
- For better error detection enable CONFIG_STACKTRACE.
- Currently CONFIG_KASAN doesn't work with CONFIG_DEBUG_SLAB
- (the resulting kernel does not boot).
- config KERNEL_KASAN_EXTRA
- bool "KAsan: extra checks"
- depends on KERNEL_KASAN && KERNEL_DEBUG_KERNEL
- help
- This enables further checks in the kernel address sanitizer, for now
- it only includes the address-use-after-scope check that can lead
- to excessive kernel stack usage, frame size warnings and longer
- compile time.
- https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 has more
- config KERNEL_KASAN_VMALLOC
- bool "Back mappings in vmalloc space with real shadow memory"
- depends on KERNEL_KASAN
- help
- By default, the shadow region for vmalloc space is the read-only
- zero page. This means that KASAN cannot detect errors involving
- vmalloc space.
- Enabling this option will hook in to vmap/vmalloc and back those
- mappings with real shadow memory allocated on demand. This allows
- for KASAN to detect more sorts of errors (and to support vmapped
- stacks), but at the cost of higher memory usage.
- This option depends on HAVE_ARCH_KASAN_VMALLOC, but we can't
- depend on that in here, so it is possible that enabling this
- will have no effect.
- if KERNEL_KASAN
- config KERNEL_KASAN_GENERIC
- def_bool y
- config KERNEL_KASAN_SW_TAGS
- def_bool n
- endif
- choice
- prompt "Instrumentation type"
- depends on KERNEL_KASAN
- default KERNEL_KASAN_OUTLINE
- config KERNEL_KASAN_OUTLINE
- bool "Outline instrumentation"
- help
- Before every memory access compiler insert function call
- __asan_load*/__asan_store*. These functions performs check
- of shadow memory. This is slower than inline instrumentation,
- however it doesn't bloat size of kernel's .text section so
- much as inline does.
- config KERNEL_KASAN_INLINE
- bool "Inline instrumentation"
- help
- Compiler directly inserts code checking shadow memory before
- memory accesses. This is faster than outline (in some workloads
- it gives about x2 boost over outline instrumentation), but
- make kernel's .text size much bigger.
- This requires a gcc version of 5.0 or later.
- endchoice
- config KERNEL_KCOV
- bool "Compile the kernel with code coverage for fuzzing"
- select KERNEL_DEBUG_FS
- help
- KCOV exposes kernel code coverage information in a form suitable
- for coverage-guided fuzzing (randomized testing).
- If RANDOMIZE_BASE is enabled, PC values will not be stable across
- different machines and across reboots. If you need stable PC values,
- disable RANDOMIZE_BASE.
- For more details, see Documentation/kcov.txt.
- config KERNEL_KCOV_ENABLE_COMPARISONS
- bool "Enable comparison operands collection by KCOV"
- depends on KERNEL_KCOV
- help
- KCOV also exposes operands of every comparison in the instrumented
- code along with operand sizes and PCs of the comparison instructions.
- These operands can be used by fuzzing engines to improve the quality
- of fuzzing coverage.
- config KERNEL_KCOV_INSTRUMENT_ALL
- bool "Instrument all code by default"
- depends on KERNEL_KCOV
- default y if KERNEL_KCOV
- help
- If you are doing generic system call fuzzing (like e.g. syzkaller),
- then you will want to instrument the whole kernel and you should
- say y here. If you are doing more targeted fuzzing (like e.g.
- filesystem fuzzing with AFL) then you will want to enable coverage
- for more specific subsets of files, and should say n here.
- config KERNEL_TASKSTATS
- bool "Compile the kernel with task resource/io statistics and accounting"
- 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
- config KERNEL_FTRACE_SYSCALLS
- bool "Trace system calls"
- depends on KERNEL_FTRACE
- config KERNEL_ENABLE_DEFAULT_TRACERS
- bool "Trace process context switches and events"
- depends on KERNEL_FTRACE
- config KERNEL_FUNCTION_TRACER
- bool "Function tracer"
- depends on KERNEL_FTRACE
- config KERNEL_FUNCTION_GRAPH_TRACER
- bool "Function graph tracer"
- depends on KERNEL_FUNCTION_TRACER
- config KERNEL_DYNAMIC_FTRACE
- bool "Enable/disable function tracing dynamically"
- depends on KERNEL_FUNCTION_TRACER
- config KERNEL_FUNCTION_PROFILER
- bool "Function profiler"
- depends on KERNEL_FUNCTION_TRACER
- config KERNEL_IRQSOFF_TRACER
- bool "Interrupts-off Latency Tracer"
- depends on KERNEL_FTRACE
- help
- This option measures the time spent in irqs-off critical
- sections, with microsecond accuracy.
- The default measurement method is a maximum search, which is
- disabled by default and can be runtime (re-)started
- via:
- echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
- (Note that kernel size and overhead increase with this option
- enabled. This option and the preempt-off timing option can be
- used together or separately.)
- config KERNEL_PREEMPT_TRACER
- bool "Preemption-off Latency Tracer"
- depends on KERNEL_FTRACE
- help
- This option measures the time spent in preemption-off critical
- sections, with microsecond accuracy.
- The default measurement method is a maximum search, which is
- disabled by default and can be runtime (re-)started
- via:
- echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
- (Note that kernel size and overhead increase with this option
- enabled. This option and the irqs-off timing option can be
- used together or separately.)
- config KERNEL_HIST_TRIGGERS
- bool "Histogram triggers"
- depends on KERNEL_FTRACE
- help
- Hist triggers allow one or more arbitrary trace event fields to be
- aggregated into hash tables and dumped to stdout by reading a
- debugfs/tracefs file. They're useful for gathering quick and dirty
- (though precise) summaries of event activity as an initial guide for
- further investigation using more advanced tools.
- Inter-event tracing of quantities such as latencies is also
- supported using hist triggers under this option.
- config KERNEL_DEBUG_KERNEL
- bool
- 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_INFO_BTF
- bool "Enable additional BTF type information"
- depends on !HOST_OS_MACOS
- depends on KERNEL_DEBUG_INFO && !KERNEL_DEBUG_INFO_REDUCED
- select DWARVES
- help
- Generate BPF Type Format (BTF) information from DWARF debug info.
- Turning this on expects presence of pahole tool, which will convert
- DWARF type info into equivalent deduplicated BTF type info.
- Required to run BPF CO-RE applications.
- config KERNEL_DEBUG_INFO_REDUCED
- bool "Reduce debugging information"
- default y
- depends on KERNEL_DEBUG_INFO
- help
- If you say Y here gcc is instructed to generate less debugging
- information for structure types. This means that tools that
- need full debugging information (like kgdb or systemtap) won't
- be happy. But if you merely need debugging information to
- resolve line numbers there is no loss. Advantage is that
- build directory object sizes shrink dramatically over a full
- DEBUG_INFO build and compile times are reduced too.
- Only works with newer gcc versions.
- config KERNEL_FRAME_WARN
- int
- range 0 8192
- default 1280 if KERNEL_KASAN && !ARCH_64BIT
- default 1024 if !ARCH_64BIT
- default 2048 if ARCH_64BIT
- help
- Tell the compiler to warn at build time for stack frames larger than this.
- Setting this too low will cause a lot of warnings.
- Setting it to 0 disables the warning.
- # KERNEL_DEBUG_LL symbols must have the default value set as otherwise
- # KConfig wont evaluate them unless KERNEL_EARLY_PRINTK is selected
- # which means that buildroot wont override the DEBUG_LL symbols in target
- # kernel configurations and lead to devices that dont have working console
- 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_DEBUG_VIRTUAL
- bool "Compile the kernel with VM translations debugging"
- select KERNEL_DEBUG_KERNEL
- help
- Enable checks sanity checks to catch invalid uses of
- virt_to_phys()/phys_to_virt() against the non-linear address space.
- config KERNEL_DYNAMIC_DEBUG
- bool "Compile the kernel with dynamic printk"
- select KERNEL_DEBUG_FS
- 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
- 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"
- 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_EVENTS
- bool
- default y if KERNEL_KPROBES
- config KERNEL_BPF_EVENTS
- bool "Compile the kernel with BPF event support"
- select KERNEL_KPROBES
- help
- Allows to attach BPF programs to kprobe, uprobe and tracepoint events.
- This is required to use BPF maps of type BPF_MAP_TYPE_PERF_EVENT_ARRAY
- for sending data from BPF programs to user-space for post-processing
- or logging.
- config KERNEL_BPF_KPROBE_OVERRIDE
- bool
- depends on KERNEL_KPROBES
- default n
- config KERNEL_AIO
- bool "Compile the kernel with asynchronous IO support"
- default y if !SMALL_FLASH
- config KERNEL_IO_URING
- bool "Compile the kernel with io_uring support"
- depends on !SMALL_FLASH
- default y if (x86_64 || aarch64)
- config KERNEL_FHANDLE
- bool "Compile the kernel with support for fhandle syscalls"
- default y if !SMALL_FLASH
- config KERNEL_FANOTIFY
- bool "Compile the kernel with modern file notification support"
- default y if !SMALL_FLASH
- config KERNEL_BLK_DEV_BSG
- bool "Compile the kernel with SCSI generic v4 support for any block device"
- config KERNEL_TRANSPARENT_HUGEPAGE
- bool
- choice
- prompt "Transparent Hugepage Support sysfs defaults"
- depends on KERNEL_TRANSPARENT_HUGEPAGE
- default KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
- config KERNEL_TRANSPARENT_HUGEPAGE_ALWAYS
- bool "always"
- config KERNEL_TRANSPARENT_HUGEPAGE_MADVISE
- bool "madvise"
- endchoice
- config KERNEL_HUGETLBFS
- bool
- config KERNEL_HUGETLB_PAGE
- bool "Compile the kernel with HugeTLB support"
- select KERNEL_TRANSPARENT_HUGEPAGE
- select KERNEL_HUGETLBFS
- 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
- config KERNEL_SOFTLOCKUP_DETECTOR
- bool "Compile the kernel with detect Soft Lockups"
- depends on KERNEL_DEBUG_KERNEL
- help
- Say Y here to enable the kernel to act as a watchdog to detect
- soft lockups.
- Softlockups are bugs that cause the kernel to loop in kernel
- mode for more than 20 seconds, without giving other tasks a
- chance to run. The current stack trace is displayed upon
- detection and the system will stay locked up.
- config KERNEL_HARDLOCKUP_DETECTOR
- bool "Compile the kernel with detect Hard Lockups"
- depends on KERNEL_DEBUG_KERNEL
- help
- Say Y here to enable the kernel to act as a watchdog to detect
- hard lockups.
- Hardlockups are bugs that cause the CPU to loop in kernel mode
- for more than 10 seconds, without letting other interrupts have a
- chance to run. The current stack trace is displayed upon detection
- and the system will stay locked up.
- config KERNEL_DETECT_HUNG_TASK
- bool "Compile the kernel with detect Hung Tasks"
- depends on KERNEL_DEBUG_KERNEL
- default KERNEL_SOFTLOCKUP_DETECTOR
- help
- Say Y here to enable the kernel to detect "hung tasks",
- which are bugs that cause the task to be stuck in
- uninterruptible "D" state indefinitely.
- When a hung task is detected, the kernel will print the
- current stack trace (which you should report), but the
- task will stay in uninterruptible state. If lockdep is
- enabled then all held locks will also be reported. This
- feature has negligible overhead.
- config KERNEL_WQ_WATCHDOG
- bool "Compile the kernel with detect Workqueue Stalls"
- depends on KERNEL_DEBUG_KERNEL
- help
- Say Y here to enable stall detection on workqueues. If a
- worker pool doesn't make forward progress on a pending work
- item for over a given amount of time, 30s by default, a
- warning message is printed along with dump of workqueue
- state. This can be configured through kernel parameter
- "workqueue.watchdog_thresh" and its sysfs counterpart.
- config KERNEL_DEBUG_ATOMIC_SLEEP
- bool "Compile the kernel with sleep inside atomic section checking"
- depends on KERNEL_DEBUG_KERNEL
- help
- If you say Y here, various routines which may sleep will become very
- noisy if they are called inside atomic sections: when a spinlock is
- held, inside an rcu read side critical section, inside preempt disabled
- sections, inside an interrupt, etc...
- config KERNEL_DEBUG_VM
- bool "Compile the kernel with debug VM"
- depends on KERNEL_DEBUG_KERNEL
- help
- Enable this to turn on extended checks in the virtual-memory system
- that may impact performance.
- If unsure, say 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_PROC_KCORE
- bool
- config KERNEL_CRASH_DUMP
- depends on i386 || x86_64 || arm || armeb
- select KERNEL_KEXEC
- select KERNEL_PROC_VMCORE
- select KERNEL_PROC_KCORE
- 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"
- config KERNEL_DEVTMPFS
- bool "Compile the kernel with device tmpfs enabled"
- 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"
- endif
- config KERNEL_KEYS
- bool "Enable kernel access key retention support"
- default !SMALL_FLASH
- config KERNEL_PERSISTENT_KEYRINGS
- bool "Enable kernel persistent keyrings"
- depends on KERNEL_KEYS
- config KERNEL_KEYS_REQUEST_CACHE
- bool "Enable temporary caching of the last request_key() result"
- depends on KERNEL_KEYS
- config KERNEL_BIG_KEYS
- bool "Enable large payload keys on kernel keyrings"
- depends on KERNEL_KEYS
- #
- # CGROUP support symbols
- #
- config KERNEL_CGROUPS
- bool "Enable kernel cgroups"
- default y if !SMALL_FLASH
- if KERNEL_CGROUPS
- config KERNEL_CGROUP_DEBUG
- bool "Example debug cgroup subsystem"
- help
- This option enables a simple cgroup subsystem that
- exports useful debugging information about the cgroups
- framework.
- config KERNEL_FREEZER
- bool
- config KERNEL_CGROUP_FREEZER
- bool "legacy Freezer cgroup subsystem"
- select KERNEL_FREEZER
- help
- Provides a way to freeze and unfreeze all tasks in a
- cgroup.
- (legacy cgroup1-only controller, in cgroup2 freezer
- is integrated in the Memory controller)
- config KERNEL_CGROUP_DEVICE
- bool "legacy Device controller for cgroups"
- help
- Provides a cgroup implementing whitelists for devices which
- a process in the cgroup can mknod or open.
- (legacy cgroup1-only controller)
- config KERNEL_CGROUP_HUGETLB
- bool "HugeTLB controller"
- select KERNEL_HUGETLB_PAGE
- 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_CGROUP_RDMA
- bool "RDMA controller for cgroups"
- default y
- config KERNEL_CGROUP_BPF
- bool "Support for eBPF programs attached to cgroups"
- default y
- config KERNEL_CPUSETS
- bool "Cpuset support"
- default y
- 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"
- depends on KERNEL_CPUSETS
- config KERNEL_CGROUP_CPUACCT
- bool "Simple CPU accounting cgroup subsystem"
- default y
- 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 y
- 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 y
- select KERNEL_FREEZER
- depends on KERNEL_RESOURCE_COUNTERS
- 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 y
- 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"
- 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 y
- 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
- 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 y
- 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 y
- config KERNEL_CFS_BANDWIDTH
- bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
- default y
- 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 y
- 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
- 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"
- 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 "legacy Control Group Classifier"
- config KERNEL_CGROUP_NET_CLASSID
- bool "legacy Network classid cgroup"
- config KERNEL_CGROUP_NET_PRIO
- bool "legacy Network priority cgroup"
- endif
- #
- # Namespace support symbols
- #
- config KERNEL_NAMESPACES
- bool "Enable kernel namespaces"
- default y if !SMALL_FLASH
- 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
- config KERNEL_DEVPTS_MULTIPLE_INSTANCES
- bool "Support multiple instances of devpts"
- default y if !SMALL_FLASH
- 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 if !SMALL_FLASH
- 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.
- config KERNEL_SECCOMP_FILTER
- bool
- default y if !SMALL_FLASH
- config KERNEL_SECCOMP
- bool "Enable seccomp support"
- depends on !(TARGET_uml)
- select KERNEL_SECCOMP_FILTER
- default y if !SMALL_FLASH
- 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.
- if KERNEL_IP_MROUTE
- config KERNEL_IP_MROUTE_MULTIPLE_TABLES
- def_bool y
- config KERNEL_IP_PIMSM_V1
- def_bool y
- config KERNEL_IP_PIMSM_V2
- def_bool y
- endif
- #
- # 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.
- if KERNEL_IPV6_MROUTE
- config KERNEL_IPV6_MROUTE_MULTIPLE_TABLES
- def_bool y
- config KERNEL_IPV6_PIMSM_V2
- def_bool y
- endif
- config KERNEL_IPV6_SEG6_LWTUNNEL
- bool "Enable support for lightweight tunnels"
- default y if !SMALL_FLASH
- help
- Using lwtunnel (needed for IPv6 segment routing) requires ip-full package.
- config KERNEL_LWTUNNEL_BPF
- def_bool n
- endif
- #
- # Miscellaneous network configuration
- #
- config KERNEL_NET_L3_MASTER_DEV
- bool "L3 Master device support"
- help
- This module provides glue between core networking code and device
- drivers to support L3 master devices like VRF.
- config KERNEL_XDP_SOCKETS
- bool "XDP sockets support"
- help
- XDP sockets allows a channel between XDP programs and
- userspace applications.
- config KERNEL_WIRELESS_EXT
- def_bool n
- config KERNEL_WEXT_CORE
- def_bool KERNEL_WIRELESS_EXT
- config KERNEL_WEXT_PRIV
- def_bool KERNEL_WIRELESS_EXT
- config KERNEL_WEXT_PROC
- def_bool KERNEL_WIRELESS_EXT
- config KERNEL_WEXT_SPY
- def_bool KERNEL_WIRELESS_EXT
- config KERNEL_PAGE_POOL
- def_bool n
- config KERNEL_PAGE_POOL_STATS
- bool "Page pool stats support"
- depends on KERNEL_PAGE_POOL
- #
- # 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"
- 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. (libreCMC 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
- config KERNEL_JFFS2_FS_POSIX_ACL
- bool "Enable POSIX ACL for JFFS2 Filesystems"
- select KERNEL_FS_POSIX_ACL
- config KERNEL_TMPFS_POSIX_ACL
- bool "Enable POSIX ACL for TMPFS Filesystems"
- select KERNEL_FS_POSIX_ACL
- 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_HFSPLUS_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"
- config KERNEL_NFSD_V2_ACL_SUPPORT
- bool "Enable ACLs for NFSDv2"
- config KERNEL_NFSD_V3_ACL_SUPPORT
- bool "Enable ACLs for NFSDv3"
- 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
- config KERNEL_SQUASHFS_XATTR
- bool "Squashfs XATTR support"
- #
- # compile optimization 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
- config KERNEL_AUDIT
- bool "Auditing support"
- config KERNEL_SECURITY
- bool "Enable different security models"
- config KERNEL_SECURITY_NETWORK
- bool "Socket and Networking Security Hooks"
- select KERNEL_SECURITY
- config KERNEL_SECURITY_SELINUX
- bool "NSA SELinux Support"
- select KERNEL_SECURITY_NETWORK
- select KERNEL_AUDIT
- config KERNEL_SECURITY_SELINUX_BOOTPARAM
- bool "NSA SELinux boot parameter"
- depends on KERNEL_SECURITY_SELINUX
- default y
- config KERNEL_SECURITY_SELINUX_DISABLE
- bool "NSA SELinux runtime disable"
- depends on KERNEL_SECURITY_SELINUX
- config KERNEL_SECURITY_SELINUX_DEVELOP
- bool "NSA SELinux Development Support"
- depends on KERNEL_SECURITY_SELINUX
- default y
- config KERNEL_SECURITY_SELINUX_SIDTAB_HASH_BITS
- int
- depends on KERNEL_SECURITY_SELINUX
- default 9
- config KERNEL_SECURITY_SELINUX_SID2STR_CACHE_SIZE
- int
- depends on KERNEL_SECURITY_SELINUX
- default 256
- config KERNEL_LSM
- string
- default "lockdown,yama,loadpin,safesetid,integrity,selinux"
- depends on KERNEL_SECURITY_SELINUX
- config KERNEL_EXT4_FS_SECURITY
- bool "Ext4 Security Labels"
- config KERNEL_F2FS_FS_SECURITY
- bool "F2FS Security Labels"
- config KERNEL_UBIFS_FS_SECURITY
- bool "UBIFS Security Labels"
- config KERNEL_JFFS2_FS_SECURITY
- bool "JFFS2 Security Labels"
- config KERNEL_WERROR
- bool "Compile the kernel with warnings as errors"
- help
- A kernel build should not cause any compiler warnings, and this
- enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags
- to enforce that rule by default. Certain warnings from other tools
- such as the linker may be upgraded to errors with this option as
- well.
- However, if you have a new (or very old) compiler or linker with odd
- and unusual warnings, or you have some architecture with problems,
- you may need to disable this config option in order to
- successfully build the kernel.
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