The patch titled
Subject: arm64/kasan: don't allocate extra shadow memory
has been added to the -mm tree. Its filename is
arm64-kasan-dont-allocate-extra-shadow-memory.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/arm64-kasan-dont-allocate-extra-shadow-memory.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/arm64-kasan-dont-allocate-extra-shadow-memory.patch
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------------------------------------------------------
From: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Subject: arm64/kasan: don't allocate extra shadow memory
We used to read several bytes of the shadow memory in advance. Therefore
additional shadow memory mapped to prevent crash if speculative load would
happen near the end of the mapped shadow memory.
Now we don't have such speculative loads, so we no longer need to map
additional shadow memory.
Link: http://lkml.kernel.org/r/20170601162338.23540-3-aryabinin@xxxxxxxxxxxxx
Signed-off-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/mm/kasan_init.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff -puN arch/arm64/mm/kasan_init.c~arm64-kasan-dont-allocate-extra-shadow-memory arch/arm64/mm/kasan_init.c
--- a/arch/arm64/mm/kasan_init.c~arm64-kasan-dont-allocate-extra-shadow-memory
+++ a/arch/arm64/mm/kasan_init.c
@@ -191,14 +191,8 @@ void __init kasan_init(void)
if (start >= end)
break;
- /*
- * end + 1 here is intentional. We check several shadow bytes in
- * advance to slightly speed up fastpath. In some rare cases
- * we could cross boundary of mapped shadow, so we just map
- * some more here.
- */
vmemmap_populate((unsigned long)kasan_mem_to_shadow(start),
- (unsigned long)kasan_mem_to_shadow(end) + 1,
+ (unsigned long)kasan_mem_to_shadow(end),
pfn_to_nid(virt_to_pfn(start)));
}
_
Patches currently in -mm which might be from aryabinin@xxxxxxxxxxxxx are
mm-kasan-get-rid-of-speculative-shadow-checks.patch
x86-kasan-dont-allocate-extra-shadow-memory.patch
arm64-kasan-dont-allocate-extra-shadow-memory.patch
mm-kasan-add-support-for-memory-hotplug.patch
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