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authorChristoph Hellwig <hch@lst.de>2019-07-16 16:26:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-16 19:23:21 -0700
commit0bf5f9492389aa8df5c8e38fcb4488802d24504d (patch)
tree9c62b75ac595ca7dd1c0e25261c9a1ad08fb69f0
parentc633324e311243586675e732249339685e5d6faa (diff)
mm: fix the MAP_UNINITIALIZED flag
We can't expose UAPI symbols differently based on CONFIG_ symbols, as userspace won't have them available. Instead always define the flag, but only respect it based on the config option. Link: http://lkml.kernel.org/r/20190703122359.18200-2-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/xtensa/include/uapi/asm/mman.h6
-rw-r--r--include/uapi/asm-generic/mman-common.h8
-rw-r--r--mm/nommu.c4
3 files changed, 7 insertions, 11 deletions
diff --git a/arch/xtensa/include/uapi/asm/mman.h b/arch/xtensa/include/uapi/asm/mman.h
index be726062412b..ebbb48842190 100644
--- a/arch/xtensa/include/uapi/asm/mman.h
+++ b/arch/xtensa/include/uapi/asm/mman.h
@@ -56,12 +56,8 @@
#define MAP_STACK 0x40000 /* give out an address that is best suited for process/thread stacks */
#define MAP_HUGETLB 0x80000 /* create a huge page mapping */
#define MAP_FIXED_NOREPLACE 0x100000 /* MAP_FIXED which doesn't unmap underlying mapping */
-#ifdef CONFIG_MMAP_ALLOW_UNINITIALIZED
-# define MAP_UNINITIALIZED 0x4000000 /* For anonymous mmap, memory could be
+#define MAP_UNINITIALIZED 0x4000000 /* For anonymous mmap, memory could be
* uninitialized */
-#else
-# define MAP_UNINITIALIZED 0x0 /* Don't support this flag */
-#endif
/*
* Flags for msync
diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h
index abd238d0f7a4..cb556b430e71 100644
--- a/include/uapi/asm-generic/mman-common.h
+++ b/include/uapi/asm-generic/mman-common.h
@@ -19,15 +19,13 @@
#define MAP_TYPE 0x0f /* Mask for type of mapping */
#define MAP_FIXED 0x10 /* Interpret addr exactly */
#define MAP_ANONYMOUS 0x20 /* don't use a file */
-#ifdef CONFIG_MMAP_ALLOW_UNINITIALIZED
-# define MAP_UNINITIALIZED 0x4000000 /* For anonymous mmap, memory could be uninitialized */
-#else
-# define MAP_UNINITIALIZED 0x0 /* Don't support this flag */
-#endif
/* 0x0100 - 0x80000 flags are defined in asm-generic/mman.h */
#define MAP_FIXED_NOREPLACE 0x100000 /* MAP_FIXED which doesn't unmap underlying mapping */
+#define MAP_UNINITIALIZED 0x4000000 /* For anonymous mmap, memory could be
+ * uninitialized */
+
/*
* Flags for mlock
*/
diff --git a/mm/nommu.c b/mm/nommu.c
index eb3e2e558da1..fed1b6e9c89b 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1261,7 +1261,9 @@ unsigned long do_mmap(struct file *file,
add_nommu_region(region);
/* clear anonymous mappings that don't ask for uninitialized data */
- if (!vma->vm_file && !(flags & MAP_UNINITIALIZED))
+ if (!vma->vm_file &&
+ (!IS_ENABLED(CONFIG_MMAP_ALLOW_UNINITIALIZED) ||
+ !(flags & MAP_UNINITIALIZED)))
memset((void *)region->vm_start, 0,
region->vm_end - region->vm_start);