Commit 0bf5f949 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Linus Torvalds
Browse files

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: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarVladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c633324e

arch/xtensa/include/uapi/asm/mman.h

+1 −5
Original line number Diff line number Diff line
@@ -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

					 * uninitialized */

#else

# define MAP_UNINITIALIZED 0x0		/* Don't support this flag */

#endif



/*

 * Flags for msync

include/uapi/asm-generic/mman-common.h

+3 −5
Original line number Diff line number Diff line
@@ -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

 */

mm/nommu.c

+3 −1
Original line number Diff line number Diff line
@@ -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);

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