Diffstat (limited to 'init/Kconfig')
1 files changed, 22 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 54c655ce9c0..a23da9f0180 100644
@@ -1079,6 +1079,28 @@ config SLOB
+ bool "Allow mmapped anonymous memory to be uninitialized"
+ depends on EMBEDDED && !MMU
+ default n
+ Normally, and according to the Linux spec, anonymous memory obtained
+ from mmap() has it's 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/nommu-mmap.txt for more information.
bool "Profiling support (EXPERIMENTAL)"