linux-5.10/init/Kconfig

1 # SPDX-License-Identifier: GPL-2.0-only
3 	string
6 	default "/lib/modules/$(shell,uname -r)/.config"
7 	default "/etc/kernel-config"
8 	default "/boot/config-$(shell,uname -r)"
12 	string
17 	  - Re-run Kconfig when the compiler is updated
22 	  - Ensure full rebuild when the compier is updated
24 	    fixdep adds include/config/cc/version/text.h into the auto-generated
29 	def_bool $(success,echo "$(CC_VERSION_TEXT)" | grep -q gcc)
33 	default $(shell,$(srctree)/scripts/gcc-version.sh $(CC)) if CC_IS_GCC
38 	default $(shell,$(LD) --version | $(srctree)/scripts/ld-version.sh)
41 	def_bool $(success,echo "$(CC_VERSION_TEXT)" | grep -q clang)
44 	def_bool $(success,$(LD) -v | head -n 1 | grep -q LLD)
48 	default $(shell,$(srctree)/scripts/clang-version.sh $(CC))
52 	default $(shell,$(srctree)/scripts/lld-version.sh $(LD))
56 	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m64-flag)) if 64BIT
57 	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m32-flag))
61 …default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m64-flag) -static) if 6…
62 	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m32-flag) -static)
65 	def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC))
69 …nt x) { asm goto ("": "=r"(x) ::: bar); return x; bar: return 0; }' | $(CC) -x c - -c -o /dev/null)
72 …env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh)
75 	def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null)
124 	  drivers to compile-test them.
134 	  Compile test headers exported to user-space to ensure they are
135 	  self-contained, i.e. compilable as standalone units.
138 	  headers are self-contained, say Y here. Otherwise, choose N.
141 	string "Local version - append to kernel release"
143 	  Append an extra string to the end of your kernel version.
145 	  The string you set here will be appended after the contents of
147 	  object and source tree, in that order.  Your total string can
151 	bool "Automatically append version information to the version string"
159 	  A string of the format -gxxxxxxxx will be added to the localversion
160 	  if a git-based tree is found.  The string generated by this will be
164 	  (The actual string used here is the first eight characters produced
167 	    $ git rev-parse --verify HEAD
172 	string "Build ID Salt"
209 	  The linux kernel is a kind of self-extracting executable.
259 	  filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
278 	  LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
309 	string "Default init path"
319 	string "Default hostname"
352 	  DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
456 	  statistics about user, system and idle time spent on per jiffies
471 	  this also enables accounting of stolen time on logically-partitioned
484 	  kernel-user boundaries using the context tracking subsystem.
571 	bool "Enable per-task delay accounting"
592 	bool "Enable per-task storage I/O accounting"
625 	  per default but can be enabled through passing psi=1 on the
630 	  common scheduling-intense workloads in practice (such as
665 	  on-disk kernel.  This information can be extracted from the kernel
666 	  image file with the script scripts/extract-ikconfig and used as
682 	  This option enables access to the in-kernel headers that are generated during
685 	  kheaders.ko is built which can be loaded on-demand to get access to headers.
744 	int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)"
749 	  Select the size of an alternate printk per-CPU buffer where messages
751 	  be NMI messages, another one - printk recursion. The messages are
805 	  the precision of clamping aggregation and tracking at run-time.
811 	  If a second 30% boosted task should be co-scheduled on the same CPU,
822 	  clamp buckets to trade off used memory for run-time tracking
830 # For architectures that want to enable the support for NUMA-affine scheduler
838 # are unmapped instead of sending one IPI per page to flush. The architecture
847 	def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT
856 # all cpu-local but of different latencies, such as SuperH.
889 		- Documentation/scheduler/sched-design-CFS.rst	(CFS)
890 		- Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation
937 	See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information.
967 	  See Documentation/scheduler/sched-bwc.rst for more information.
976 	  schedule realtime tasks for non-root users until you allocate
978 	  See Documentation/scheduler/sched-rt-group.rst for more information.
983 	bool "Utilization clamping per group of tasks"
998 	  specified task-specific clamp value is constrained by the cgroup
1037 	  controller includes important in-kernel memory consumers per default.
1048 	  When you enable this, you can put a per cgroup limit on HugeTLB usage.
1089 	  This option extends the perf per-cpu mode to restrict monitoring
1171 	  user-space use the memory control groups to limit the amount
1257 	bool "Kernel->user space relay support (formerly relayfs)"
1275 	  etc. See <file:Documentation/admin-guide/initrd.rst> for details.
1297 	  See <file:Documentation/admin-guide/bootconfig.rst> for details.
1306 	bool "Optimize for performance (-O2)"
1309 	  with the "-O2" compiler flag for best performance and most
1310 	  helpful compile-time warnings.
1313 	bool "Optimize more for performance (-O3)"
1316 	  Choosing this option will pass "-O3" to your compiler to optimize
1320 	bool "Optimize for size (-Os)"
1322 	  Choosing this option will pass "-Os" to your compiler resulting
1341 	depends on $(cc-option,-ffunction-sections -fdata-sections)
1342 	depends on $(ld-option,--gc-sections)
1345 	  the linker by compiling with -ffunction-sections -fdata-sections,
1346 	  and linking with --gc-sections.
1348 	  This can reduce on disk and in-memory size of the kernel
1359 	depends on $(ld-option,--orphan-handling=warn)
1370 	  Enable support for /proc/sys/debug/exception-trace.
1375 	  Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1382 	  Enable support for /proc/sys/kernel/unaligned-trap
1396 	# Unhide debug options, to make the on-by-default options visible
1401 	  environments which can tolerate a "non-standard" kernel.
1405 	bool "Enable 16-bit UID system calls" if EXPERT
1409 	  This enables the legacy 16-bit UID syscall wrappers.
1415 	  This option enables support for non-root users, groups and
1510 	bool "Enable PC-Speaker support" if EXPERT
1515 	  This option allows to disable the internal PC-Speaker
1520 	bool "Enable full-sized data structures for core" if EXPERT
1533 	  run glibc-based applications correctly.
1631 	  the cost of user-space memory barriers asymmetrically by transforming
1673 	  emit the symbol references in the kallsyms table as 32-bit entries,
1680 	  On 64-bit builds, this reduces the size of the address table by 50%,
1747 	  user-space cache for the current CPU number value, which
1748 	  speeds up getting the current CPU number from user-space,
1749 	  as well as an ABI to speed up user-space operations on
1750 	  per-CPU data.
1801 	  Software events are supported either built-in or via the
1807 	  suffered, or branches mis-predicted - without slowing down the
1809 	  when a threshold number of events have passed - and can thus be
1815 	  provides per task and per CPU counters, and it provides event
1861 	  cgroup is enabled, each cache can have per memory cgroup
1878 	  On non-ancient distros (post-2000 ones) N is usually a safe choice.
1892 	  per cpu and per node queues.
1900 	   Per cpu caching is realized using slabs of objects instead
1945 	  sanity-checking than others. This option is most effective with
1953 	  utilization of a direct-mapped memory-side-cache. See section
1956 	  the presence of a memory-side-cache. There are also incidental
1959 	  default granularity of shuffling on the "MAX_ORDER - 1" i.e,
1966 	  after runtime detection of a direct-mapped memory-side-cache.
1975 	bool "SLUB per cpu partial cache"
1977 	  Per cpu partial caches accelerate objects allocation and freeing
1996 	  ELF-FDPIC binfmt's brk and stack allocator.
2000 	  userspace.  Since that isn't generally a problem on no-MMU systems,
2003 	  See Documentation/admin-guide/mm/nommu-mmap.rst for more information.
2080 	  --force).  Forced module loading sets the 'F' (forced) taint flag and
2097 	  without waiting for anyone to stop using it (using the -f option to
2140 	  <file:Documentation/admin-guide/module-signing.rst>.
2148 	  another LSM - otherwise unsigned modules will be loadable regardless
2169 	  modules must be signed manually, using the scripts/sign-file tool.
2171 comment "Do not forget to sign required modules with scripts/sign-file"
2185 	bool "Sign modules with SHA-1"
2189 	bool "Sign modules with SHA-224"
2193 	bool "Sign modules with SHA-256"
2197 	bool "Sign modules with SHA-384"
2201 	bool "Sign modules with SHA-512"
2207 	string
2222 	  module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
2224 	  Out-of-tree kernel modules installed using Kbuild will also be
2295 	  If unsure, or if you need to build out-of-tree modules, say N.
2298 	string "Whitelist of symbols to keep in ksymtab"
2301 	  By default, all unused exported symbols will be un-exported from the
2305 	  exported at all times, even in absence of in-tree users. The value to
2307 	  one per line. The path can be absolute, or relative to the kernel
2354 # macros for not-implemented syscalls in kernel/sys_ni.c and
2355 # kernel/time/posix-stubs.c. All these overrides need to be available in