From 00673f93826bf1fbde728d202c319a684bb87150 Mon Sep 17 00:00:00 2001 From: Mike Frysinger Date: Mon, 23 Nov 2009 21:35:34 -0500 Subject: nommu: use MAP_UNINITIALIZE for mallocs Now that the kernel supports MAP_UNINITIALIZE, have the malloc places use it to get real uninitialized memory on no-mmu systems. This avoids a lot of normally useless overhead involved in zeroing out all of the memory (sometimes multiple times). Signed-off-by: Mike Frysinger --- libc/stdlib/malloc-simple/alloc.c | 2 +- libc/stdlib/malloc-standard/malloc.h | 2 +- libc/stdlib/malloc/malloc.c | 2 +- libc/sysdeps/linux/alpha/bits/mman.h | 2 ++ libc/sysdeps/linux/hppa/bits/mman.h | 2 ++ libc/sysdeps/linux/mips/bits/mman.h | 2 ++ libc/sysdeps/linux/powerpc/bits/mman.h | 2 ++ libc/sysdeps/linux/sparc/bits/mman.h | 2 ++ libc/sysdeps/linux/xtensa/bits/mman.h | 2 ++ 9 files changed, 15 insertions(+), 3 deletions(-) (limited to 'libc') diff --git a/libc/stdlib/malloc-simple/alloc.c b/libc/stdlib/malloc-simple/alloc.c index 36355c1e9..51da14ac8 100644 --- a/libc/stdlib/malloc-simple/alloc.c +++ b/libc/stdlib/malloc-simple/alloc.c @@ -36,7 +36,7 @@ void *malloc(size_t size) #ifdef __ARCH_USE_MMU__ # define MMAP_FLAGS MAP_PRIVATE | MAP_ANONYMOUS #else -# define MMAP_FLAGS MAP_SHARED | MAP_ANONYMOUS +# define MMAP_FLAGS MAP_SHARED | MAP_ANONYMOUS | MAP_UNINITIALIZE #endif result = mmap((void *) 0, size + sizeof(size_t), PROT_READ | PROT_WRITE, diff --git a/libc/stdlib/malloc-standard/malloc.h b/libc/stdlib/malloc-standard/malloc.h index 90c9fd14d..7a2e66d16 100644 --- a/libc/stdlib/malloc-standard/malloc.h +++ b/libc/stdlib/malloc-standard/malloc.h @@ -356,7 +356,7 @@ __UCLIBC_MUTEX_EXTERN(__malloc_lock); #else #define MMAP(addr, size, prot) \ - (mmap((addr), (size), (prot), MAP_SHARED|MAP_ANONYMOUS, 0, 0)) + (mmap((addr), (size), (prot), MAP_SHARED|MAP_ANONYMOUS|MAP_UNINITIALIZE, 0, 0)) #endif diff --git a/libc/stdlib/malloc/malloc.c b/libc/stdlib/malloc/malloc.c index f4bbc71a2..337206f09 100644 --- a/libc/stdlib/malloc/malloc.c +++ b/libc/stdlib/malloc/malloc.c @@ -124,7 +124,7 @@ __malloc_from_heap (size_t size, struct heap_free_area **heap MAP_PRIVATE | MAP_ANONYMOUS, 0, 0); #else block = mmap ((void *)0, block_size, PROT_READ | PROT_WRITE, - MAP_SHARED | MAP_ANONYMOUS, 0, 0); + MAP_SHARED | MAP_ANONYMOUS | MAP_UNINITIALIZE, 0, 0); #endif #endif /* MALLOC_USE_SBRK */ diff --git a/libc/sysdeps/linux/alpha/bits/mman.h b/libc/sysdeps/linux/alpha/bits/mman.h index 2f0e56491..cafad4a24 100644 --- a/libc/sysdeps/linux/alpha/bits/mman.h +++ b/libc/sysdeps/linux/alpha/bits/mman.h @@ -71,6 +71,8 @@ # define MAP_NORESERVE 0x10000 /* Don't check for reservations. */ # define MAP_POPULATE 0x20000 /* Populate (prefault) pagetables. */ # define MAP_NONBLOCK 0x40000 /* Do not block on IO. */ +# define MAP_UNINITIALIZE 0x4000000 /* For anonymous mmap, memory could + be uninitialized. */ #endif /* Flags to `msync'. */ diff --git a/libc/sysdeps/linux/hppa/bits/mman.h b/libc/sysdeps/linux/hppa/bits/mman.h index 54531ecf2..7f9bf4ed6 100644 --- a/libc/sysdeps/linux/hppa/bits/mman.h +++ b/libc/sysdeps/linux/hppa/bits/mman.h @@ -45,6 +45,8 @@ #define MAP_GROWSDOWN 0x8000 /* stack-like segment */ #define MAP_POPULATE 0x10000 /* populate (prefault) pagetables */ #define MAP_NONBLOCK 0x20000 /* do not block on IO */ +#define MAP_UNINITIALIZE 0x4000000 /* For anonymous mmap, memory could + be uninitialized. */ #define MS_SYNC 1 /* synchronous memory sync */ #define MS_ASYNC 2 /* sync memory asynchronously */ diff --git a/libc/sysdeps/linux/mips/bits/mman.h b/libc/sysdeps/linux/mips/bits/mman.h index 47d33933a..c480be46e 100644 --- a/libc/sysdeps/linux/mips/bits/mman.h +++ b/libc/sysdeps/linux/mips/bits/mman.h @@ -66,6 +66,8 @@ # define MAP_LOCKED 0x8000 /* pages are locked */ # define MAP_POPULATE 0x10000 /* populate (prefault) pagetables */ # define MAP_NONBLOCK 0x20000 /* do not block on IO */ +# define MAP_UNINITIALIZE 0x4000000 /* For anonymous mmap, memory could + be uninitialized. */ #endif /* Flags to `msync'. */ diff --git a/libc/sysdeps/linux/powerpc/bits/mman.h b/libc/sysdeps/linux/powerpc/bits/mman.h index e03ab7ff8..2d234c5fc 100644 --- a/libc/sysdeps/linux/powerpc/bits/mman.h +++ b/libc/sysdeps/linux/powerpc/bits/mman.h @@ -63,6 +63,8 @@ # define MAP_NORESERVE 0x00040 /* Don't check for reservations. */ # define MAP_POPULATE 0x08000 /* Populate (prefault) pagetables. */ # define MAP_NONBLOCK 0x10000 /* Do not block on IO. */ +# define MAP_UNINITIALIZE 0x4000000 /* For anonymous mmap, memory could + be uninitialized. */ #endif /* Flags to `msync'. */ diff --git a/libc/sysdeps/linux/sparc/bits/mman.h b/libc/sysdeps/linux/sparc/bits/mman.h index be2b7eb28..74921e4c5 100644 --- a/libc/sysdeps/linux/sparc/bits/mman.h +++ b/libc/sysdeps/linux/sparc/bits/mman.h @@ -65,6 +65,8 @@ # define _MAP_NEW 0x80000000 /* Binary compatibility with SunOS. */ # define MAP_POPULATE 0x8000 /* Populate (prefault) pagetables. */ # define MAP_NONBLOCK 0x10000 /* Do not block on IO. */ +# define MAP_UNINITIALIZE 0x4000000 /* For anonymous mmap, memory could + be uninitialized. */ #endif /* Flags to `msync'. */ diff --git a/libc/sysdeps/linux/xtensa/bits/mman.h b/libc/sysdeps/linux/xtensa/bits/mman.h index d3beae6aa..fead3ac20 100644 --- a/libc/sysdeps/linux/xtensa/bits/mman.h +++ b/libc/sysdeps/linux/xtensa/bits/mman.h @@ -64,6 +64,8 @@ # define MAP_NORESERVE 0x0400 /* Don't check for reservations. */ # define MAP_POPULATE 0x10000 /* Populate (prefault) pagetables. */ # define MAP_NONBLOCK 0x20000 /* Do not block on IO. */ +# define MAP_UNINITIALIZE 0x4000000 /* For anonymous mmap, memory could + be uninitialized. */ #endif /* Flags to `msync'. */ -- cgit v1.2.3