arm64: lib: use C string functions with KASAN enabled

ARM64 has asm implementation of memchr(), memcmp(), str[r]chr(),
str[n]cmp(), str[n]len().  KASAN don't see memory accesses in asm code,
thus it can potentially miss many bugs.

Ifdef out __HAVE_ARCH_* defines of these functions when KASAN is enabled,
so the generic implementations from lib/string.c will be used.

We can't just remove the asm functions because efistub uses them.  And we
can't have two non-weak functions either, so declare the asm functions as
weak.

Link: http://lkml.kernel.org/r/20180920135631.23833-2-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Kyeongdon Kim <kyeongdon.kim@lge.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

8 files changed, 8 insertions, 8 deletions

diff --git a/arch/arm64/lib/memchr.S b/arch/arm64/lib/memchr.S
index 4444c1d25f4b..0f164a4baf52 100644
--- a/arch/arm64/lib/memchr.S
+++ b/arch/arm64/lib/memchr.S
@@ -30,7 +30,7 @@
  * Returns:
  *	x0 - address of first occurrence of 'c' or 0
  */
-ENTRY(memchr)
+WEAK(memchr)
 	and	w1, w1, #0xff
 1:	subs	x2, x2, #1
 	b.mi	2f
diff --git a/arch/arm64/lib/memcmp.S b/arch/arm64/lib/memcmp.S
index 2a4e239bd17a..fb295f52e9f8 100644
--- a/arch/arm64/lib/memcmp.S
+++ b/arch/arm64/lib/memcmp.S
@@ -58,7 +58,7 @@ pos		.req	x11
 limit_wd	.req	x12
 mask		.req	x13
 
-ENTRY(memcmp)
+WEAK(memcmp)
 	cbz	limit, .Lret0
 	eor	tmp1, src1, src2
 	tst	tmp1, #7
diff --git a/arch/arm64/lib/strchr.S b/arch/arm64/lib/strchr.S
index dae0cf5591f9..7c83091d1bcd 100644
--- a/arch/arm64/lib/strchr.S
+++ b/arch/arm64/lib/strchr.S
@@ -29,7 +29,7 @@
  * Returns:
  *	x0 - address of first occurrence of 'c' or 0
  */
-ENTRY(strchr)
+WEAK(strchr)
 	and	w1, w1, #0xff
 1:	ldrb	w2, [x0], #1
 	cmp	w2, w1
diff --git a/arch/arm64/lib/strcmp.S b/arch/arm64/lib/strcmp.S
index 471fe61760ef..7d5d15398bfb 100644
--- a/arch/arm64/lib/strcmp.S
+++ b/arch/arm64/lib/strcmp.S
@@ -60,7 +60,7 @@ tmp3		.req	x9
 zeroones	.req	x10
 pos		.req	x11
 
-ENTRY(strcmp)
+WEAK(strcmp)
 	eor	tmp1, src1, src2
 	mov	zeroones, #REP8_01
 	tst	tmp1, #7
diff --git a/arch/arm64/lib/strlen.S b/arch/arm64/lib/strlen.S
index 55ccc8e24c08..8e0b14205dcb 100644
--- a/arch/arm64/lib/strlen.S
+++ b/arch/arm64/lib/strlen.S
@@ -56,7 +56,7 @@ pos		.req	x12
 #define REP8_7f 0x7f7f7f7f7f7f7f7f
 #define REP8_80 0x8080808080808080
 
-ENTRY(strlen)
+WEAK(strlen)
 	mov	zeroones, #REP8_01
 	bic	src, srcin, #15
 	ands	tmp1, srcin, #15
diff --git a/arch/arm64/lib/strncmp.S b/arch/arm64/lib/strncmp.S
index e267044761c6..66bd145935d9 100644
--- a/arch/arm64/lib/strncmp.S
+++ b/arch/arm64/lib/strncmp.S
@@ -64,7 +64,7 @@ limit_wd	.req	x13
 mask		.req	x14
 endloop		.req	x15
 
-ENTRY(strncmp)
+WEAK(strncmp)
 	cbz	limit, .Lret0
 	eor	tmp1, src1, src2
 	mov	zeroones, #REP8_01
diff --git a/arch/arm64/lib/strnlen.S b/arch/arm64/lib/strnlen.S
index eae38da6e0bb..355be04441fe 100644
--- a/arch/arm64/lib/strnlen.S
+++ b/arch/arm64/lib/strnlen.S
@@ -59,7 +59,7 @@ limit_wd	.req	x14
 #define REP8_7f 0x7f7f7f7f7f7f7f7f
 #define REP8_80 0x8080808080808080
 
-ENTRY(strnlen)
+WEAK(strnlen)
 	cbz	limit, .Lhit_limit
 	mov	zeroones, #REP8_01
 	bic	src, srcin, #15
diff --git a/arch/arm64/lib/strrchr.S b/arch/arm64/lib/strrchr.S
index f8e2784d5752..ea84924d5990 100644
--- a/arch/arm64/lib/strrchr.S
+++ b/arch/arm64/lib/strrchr.S
@@ -29,7 +29,7 @@
  * Returns:
  *	x0 - address of last occurrence of 'c' or 0
  */
-ENTRY(strrchr)
+WEAK(strrchr)
 	mov	x3, #0
 	and	w1, w1, #0xff
 1:	ldrb	w2, [x0], #1