Enable the extended profiling support mechanisms used by profilers such
as OProfile.
+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_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_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
+
+
+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"
default n
select KERNEL_DEBUG_KERNEL
default n
+config KERNEL_LOCKUP_DETECTOR
+ bool "Compile the kernel with detect Hard and Soft Lockups"
+ depends on KERNEL_DEBUG_KERNEL
+ help
+ Say Y here to enable the kernel to act as a watchdog to detect
+ hard and 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.
+
+ 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.
+
+ The overhead should be minimal. A periodic hrtimer runs to
+ generate interrupts and kick the watchdog task every 4 seconds.
+ An NMI is generated every 10 seconds or so to check for hardlockups.
+
+ The frequency of hrtimer and NMI events and the soft and hard lockup
+ thresholds can be controlled through the sysctl watchdog_thresh.
+
+config KERNEL_DETECT_HUNG_TASK
+ bool "Compile the kernel with detect Hung Tasks"
+ depends on KERNEL_DEBUG_KERNEL
+ default KERNEL_LOCKUP_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_BLK_DEV_THROTTLING
bool "Enable throttling policy"
- default y if TARGET_brcm2708
+ default y if TARGET_bcm27xx
config KERNEL_BLK_DEV_THROTTLING_LOW
bool "Block throttling .low limit interface support (EXPERIMENTAL)"
config KERNEL_DEVPTS_MULTIPLE_INSTANCES
bool "Support multiple instances of devpts"
- default y
+ 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),
config KERNEL_POSIX_MQUEUE
bool "POSIX Message Queues"
- default y
+ 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
select KERNEL_FS_POSIX_ACL
default y if USE_FS_ACL_ATTR
- config KERNEL_HFSPLUG_FS_POSIX_ACL
+ 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
projects / openwrt / openwrt.git / blobdiff