[git commit nptl] nommu: use MAP_UNINITIALIZE for mallocs
Mike Frysinger
vapier at gentoo.org
Fri Nov 27 09:03:24 UTC 2009
commit: http://git.uclibc.org/uClibc/commit/?id=00673f93826bf1fbde728d202c319a684bb87150
branch: http://git.uclibc.org/uClibc/commit/?id=refs/heads/nptl
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 <vapier at gentoo.org>
---
ldso/ldso/dl-elf.c | 2 +-
ldso/ldso/ldso.c | 2 +-
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 ++
11 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/ldso/ldso/dl-elf.c b/ldso/ldso/dl-elf.c
index e7cb138..6bf5bbd 100644
--- a/ldso/ldso/dl-elf.c
+++ b/ldso/ldso/dl-elf.c
@@ -376,7 +376,7 @@ struct elf_resolve *_dl_load_elf_shared_library(int secure,
}
}
header = _dl_mmap((void *) 0, _dl_pagesize, PROT_READ | PROT_WRITE,
- MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_UNINITIALIZE, -1, 0);
if (_dl_mmap_check_error(header)) {
_dl_dprintf(2, "%s:%i: can't map '%s'\n", _dl_progname, __LINE__, libname);
_dl_internal_error_number = LD_ERROR_MMAP_FAILED;
diff --git a/ldso/ldso/ldso.c b/ldso/ldso/ldso.c
index 45d4995..01e7071 100644
--- a/ldso/ldso/ldso.c
+++ b/ldso/ldso/ldso.c
@@ -193,7 +193,7 @@ void *_dl_malloc(size_t size)
_dl_debug_early("mmapping more memory\n");
_dl_mmap_zero = _dl_malloc_addr = _dl_mmap((void *) 0, rounded_size,
- PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_UNINITIALIZE, -1, 0);
if (_dl_mmap_check_error(_dl_mmap_zero)) {
_dl_dprintf(_dl_debug_file, "%s: mmap of a spare page failed!\n", _dl_progname);
_dl_exit(20);
diff --git a/libc/stdlib/malloc-simple/alloc.c b/libc/stdlib/malloc-simple/alloc.c
index 36355c1..51da14a 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 90c9fd1..7a2e66d 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 f4bbc71..337206f 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 2f0e564..cafad4a 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 54531ec..7f9bf4e 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 47d3393..c480be4 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 e03ab7f..2d234c5 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 be2b7eb..74921e4 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 d3beae6..fead3ac 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'. */
--
1.6.3.3
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