depends on CC_HAS_ASM_GOTO
def_bool $(success,echo 'int foo(int x) { asm goto ("": "=r"(x) ::: bar); return x; bar: return 0; }' | $(CC) -x c - -c -o /dev/null)
+config CC_HAS_ASM_GOTO_TIED_OUTPUT
+ depends on CC_HAS_ASM_GOTO_OUTPUT
+ # Detect buggy gcc and clang, fixed in gcc-11 clang-14.
+ def_bool $(success,echo 'int foo(int *x) { asm goto (".long (%l[bar]) - .\n": "+m"(*x) ::: bar); return *x; bar: return 0; }' | $CC -x c - -c -o /dev/null)
+
config TOOLS_SUPPORT_RELR
def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh)
but you may wish to use a different default here to make a minimal
system more usable with less configuration.
-#
-# For some reason microblaze and nios2 hard code SWAP=n. Hopefully we can
-# add proper SWAP support to them, in which case this can be remove.
-#
-config ARCH_NO_SWAP
- bool
-
-config SWAP
- bool "Support for paging of anonymous memory (swap)"
- depends on MMU && BLOCK && !ARCH_NO_SWAP
- default y
- help
- This option allows you to choose whether you want to have support
- for so called swap devices or swap files in your kernel that are
- used to provide more virtual memory than the actual RAM present
- in your computer. If unsure say Y.
-
config SYSVIPC
bool "System V IPC"
help
See the man page for more details.
config USELIB
- bool "uselib syscall"
- def_bool ALPHA || M68K || SPARC || X86_32 || IA32_EMULATION
+ bool "uselib syscall (for libc5 and earlier)"
+ default ALPHA || M68K || SPARC
help
This option enables the uselib syscall, a system call used in the
dynamic linker from libc5 and earlier. glibc does not use this
config LOG_BUF_SHIFT
int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
- range 12 25 if !H8300
- range 12 19 if H8300
+ range 12 25
default 17
depends on PRINTK
help
This bootconfig will be used if there is no initrd or no other
bootconfig in the initrd.
+config INITRAMFS_PRESERVE_MTIME
+ bool "Preserve cpio archive mtimes in initramfs"
+ default y
+ help
+ Each entry in an initramfs cpio archive carries an mtime value. When
+ enabled, extracted cpio items take this mtime, with directory mtime
+ setting deferred until after creation of any child entries.
+
+ If unsure, say Y.
+
choice
prompt "Compiler optimization level"
default CC_OPTIMIZE_FOR_PERFORMANCE
applications use these syscalls, you can disable this option to save
space.
-config HAVE_ARCH_USERFAULTFD_WP
- bool
- help
- Arch has userfaultfd write protection support
-
-config HAVE_ARCH_USERFAULTFD_MINOR
- bool
- help
- Arch has userfaultfd minor fault support
-
config MEMBARRIER
bool "Enable membarrier() system call" if EXPERT
default y
# syscall, maps, verifier
-config USERFAULTFD
- bool "Enable userfaultfd() system call"
- depends on MMU
- help
- Enable the userfaultfd() system call that allows to intercept and
- handle page faults in userland.
-
config ARCH_HAS_MEMBARRIER_CALLBACKS
bool
endmenu
-config VM_EVENT_COUNTERS
- default y
- bool "Enable VM event counters for /proc/vmstat" if EXPERT
- help
- VM event counters are needed for event counts to be shown.
- This option allows the disabling of the VM event counters
- on EXPERT systems. /proc/vmstat will only show page counts
- if VM event counters are disabled.
-
-config SLUB_DEBUG
- default y
- bool "Enable SLUB debugging support" if EXPERT
- depends on SLUB && SYSFS
- help
- SLUB has extensive debug support features. Disabling these can
- result in significant savings in code size. This also disables
- SLUB sysfs support. /sys/slab will not exist and there will be
- no support for cache validation etc.
-
-config COMPAT_BRK
- bool "Disable heap randomization"
- default y
- help
- Randomizing heap placement makes heap exploits harder, but it
- also breaks ancient binaries (including anything libc5 based).
- This option changes the bootup default to heap randomization
- disabled, and can be overridden at runtime by setting
- /proc/sys/kernel/randomize_va_space to 2.
-
- On non-ancient distros (post-2000 ones) N is usually a safe choice.
-
-choice
- prompt "Choose SLAB allocator"
- default SLUB
- help
- This option allows to select a slab allocator.
-
-config SLAB
- bool "SLAB"
- depends on !PREEMPT_RT
- select HAVE_HARDENED_USERCOPY_ALLOCATOR
- help
- The regular slab allocator that is established and known to work
- well in all environments. It organizes cache hot objects in
- per cpu and per node queues.
-
-config SLUB
- bool "SLUB (Unqueued Allocator)"
- select HAVE_HARDENED_USERCOPY_ALLOCATOR
- help
- SLUB is a slab allocator that minimizes cache line usage
- instead of managing queues of cached objects (SLAB approach).
- Per cpu caching is realized using slabs of objects instead
- of queues of objects. SLUB can use memory efficiently
- and has enhanced diagnostics. SLUB is the default choice for
- a slab allocator.
-
-config SLOB
- depends on EXPERT
- bool "SLOB (Simple Allocator)"
- depends on !PREEMPT_RT
- help
- SLOB replaces the stock allocator with a drastically simpler
- allocator. SLOB is generally more space efficient but
- does not perform as well on large systems.
-
-endchoice
-
-config SLAB_MERGE_DEFAULT
- bool "Allow slab caches to be merged"
- default y
- depends on SLAB || SLUB
- help
- For reduced kernel memory fragmentation, slab caches can be
- merged when they share the same size and other characteristics.
- This carries a risk of kernel heap overflows being able to
- overwrite objects from merged caches (and more easily control
- cache layout), which makes such heap attacks easier to exploit
- by attackers. By keeping caches unmerged, these kinds of exploits
- can usually only damage objects in the same cache. To disable
- merging at runtime, "slab_nomerge" can be passed on the kernel
- command line.
-
-config SLAB_FREELIST_RANDOM
- bool "Randomize slab freelist"
- depends on SLAB || SLUB
- help
- Randomizes the freelist order used on creating new pages. This
- security feature reduces the predictability of the kernel slab
- allocator against heap overflows.
-
-config SLAB_FREELIST_HARDENED
- bool "Harden slab freelist metadata"
- depends on SLAB || SLUB
- help
- Many kernel heap attacks try to target slab cache metadata and
- other infrastructure. This options makes minor performance
- sacrifices to harden the kernel slab allocator against common
- freelist exploit methods. Some slab implementations have more
- sanity-checking than others. This option is most effective with
- CONFIG_SLUB.
-
-config SHUFFLE_PAGE_ALLOCATOR
- bool "Page allocator randomization"
- default SLAB_FREELIST_RANDOM && ACPI_NUMA
- help
- Randomization of the page allocator improves the average
- utilization of a direct-mapped memory-side-cache. See section
- 5.2.27 Heterogeneous Memory Attribute Table (HMAT) in the ACPI
- 6.2a specification for an example of how a platform advertises
- the presence of a memory-side-cache. There are also incidental
- security benefits as it reduces the predictability of page
- allocations to compliment SLAB_FREELIST_RANDOM, but the
- default granularity of shuffling on the "MAX_ORDER - 1" i.e,
- 10th order of pages is selected based on cache utilization
- benefits on x86.
-
- While the randomization improves cache utilization it may
- negatively impact workloads on platforms without a cache. For
- this reason, by default, the randomization is enabled only
- after runtime detection of a direct-mapped memory-side-cache.
- Otherwise, the randomization may be force enabled with the
- 'page_alloc.shuffle' kernel command line parameter.
-
- Say Y if unsure.
-
-config SLUB_CPU_PARTIAL
- default y
- depends on SLUB && SMP
- bool "SLUB per cpu partial cache"
- help
- Per cpu partial caches accelerate objects allocation and freeing
- that is local to a processor at the price of more indeterminism
- in the latency of the free. On overflow these caches will be cleared
- which requires the taking of locks that may cause latency spikes.
- Typically one would choose no for a realtime system.
-
-config MMAP_ALLOW_UNINITIALIZED
- bool "Allow mmapped anonymous memory to be uninitialized"
- depends on EXPERT && !MMU
- default n
- help
- Normally, and according to the Linux spec, anonymous memory obtained
- from mmap() has its contents cleared before it is passed to
- userspace. Enabling this config option allows you to request that
- mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
- providing a huge performance boost. If this option is not enabled,
- then the flag will be ignored.
-
- This is taken advantage of by uClibc's malloc(), and also by
- ELF-FDPIC binfmt's brk and stack allocator.
-
- Because of the obvious security issues, this option should only be
- enabled on embedded devices where you control what is run in
- userspace. Since that isn't generally a problem on no-MMU systems,
- it is normally safe to say Y here.
-
- See Documentation/admin-guide/mm/nommu-mmap.rst for more information.
-
config SYSTEM_DATA_VERIFICATION
def_bool n
select SYSTEM_TRUSTED_KEYRING
rmmod). This is mainly for kernel developers and desperate users.
If unsure, say N.
+config MODULE_UNLOAD_TAINT_TRACKING
+ bool "Tainted module unload tracking"
+ depends on MODULE_UNLOAD
+ default n
+ help
+ This option allows you to maintain a record of each unloaded
+ module that tainted the kernel. In addition to displaying a
+ list of linked (or loaded) modules e.g. on detection of a bad
+ page (see bad_page()), the aforementioned details are also
+ shown. If unsure, say N.
+
config MODVERSIONS
bool "Module versioning support"
help
assembly. This can be enabled only when the target architecture
supports it.
-config MODULE_REL_CRCS
- bool
- depends on MODVERSIONS
-
config MODULE_SRCVERSION_ALL
bool "Source checksum for all modules"
help
projects / people / ms / linux.git / blobdiff