X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=init%2FKconfig;h=a23da9f0180341dd0cb8809f6108a2911336897a;hb=fcb11235d3910c39afece52f6e106a9ca565d34b;hp=54c655ce9c049f56da32c4157917e0b6caffd48f;hpb=6e0446cb4b6e2469a0db58fbe6dffcd63d3d4066;p=deliverable%2Flinux.git

diff --git a/init/Kconfig b/init/Kconfig
index 54c655ce9c04..a23da9f01803 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1079,6 +1079,28 @@ config SLOB
 
 endchoice
 
+config MMAP_ALLOW_UNINITIALIZED
+	bool "Allow mmapped anonymous memory to be uninitialized"
+	depends on EMBEDDED && !MMU
+	default n
+	help
+	  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.
+
 config PROFILING
 	bool "Profiling support (EXPERIMENTAL)"
 	help