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>
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@ -56,12 +56,8 @@
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#define MAP_STACK 0x40000 /* give out an address that is best suited for process/thread stacks */
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#define MAP_HUGETLB 0x80000 /* create a huge page mapping */
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#define MAP_FIXED_NOREPLACE 0x100000 /* MAP_FIXED which doesn't unmap underlying mapping */
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#ifdef CONFIG_MMAP_ALLOW_UNINITIALIZED
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# define MAP_UNINITIALIZED 0x4000000 /* For anonymous mmap, memory could be
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#define MAP_UNINITIALIZED 0x4000000 /* For anonymous mmap, memory could be
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* uninitialized */
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#else
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# define MAP_UNINITIALIZED 0x0 /* Don't support this flag */
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#endif
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/*
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* Flags for msync
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@ -19,15 +19,13 @@
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#define MAP_TYPE 0x0f /* Mask for type of mapping */
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#define MAP_FIXED 0x10 /* Interpret addr exactly */
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#define MAP_ANONYMOUS 0x20 /* don't use a file */
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#ifdef CONFIG_MMAP_ALLOW_UNINITIALIZED
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# define MAP_UNINITIALIZED 0x4000000 /* For anonymous mmap, memory could be uninitialized */
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#else
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# define MAP_UNINITIALIZED 0x0 /* Don't support this flag */
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#endif
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/* 0x0100 - 0x80000 flags are defined in asm-generic/mman.h */
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#define MAP_FIXED_NOREPLACE 0x100000 /* MAP_FIXED which doesn't unmap underlying mapping */
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#define MAP_UNINITIALIZED 0x4000000 /* For anonymous mmap, memory could be
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* uninitialized */
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/*
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* Flags for mlock
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*/
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@ -1261,7 +1261,9 @@ unsigned long do_mmap(struct file *file,
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add_nommu_region(region);
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/* clear anonymous mappings that don't ask for uninitialized data */
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if (!vma->vm_file && !(flags & MAP_UNINITIALIZED))
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if (!vma->vm_file &&
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(!IS_ENABLED(CONFIG_MMAP_ALLOW_UNINITIALIZED) ||
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!(flags & MAP_UNINITIALIZED)))
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memset((void *)region->vm_start, 0,
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region->vm_end - region->vm_start);
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