From 824b1bec5dc996f17c2cf8b294739e04fa116ee0 Mon Sep 17 00:00:00 2001
From: Andrey Ryabinin <aryabinin@virtuozzo.com>
Date: Mon, 10 Jul 2017 15:50:31 -0700
Subject: [PATCH 12/20] arm64/kasan: don't allocate extra shadow memory
Git-commit: 3f9ec80f7b22ec46272a32408c5cd91ae2f8c4c0
Patch-mainline: v4.13-rc1
References: bsc#1106897
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@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
arch/arm64/mm/kasan_init.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index 687a358a3733..81f03959a4ab 100644
--- a/arch/arm64/mm/kasan_init.c
+++ b/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)));
}
--
2.11.0