[PATCH v2 19/20] arm64: atomic64_dec_if_positive: fix incorrect branch condition

[Will Deacon]

If we attempt to atomic64_dec_if_positive on INT_MIN, we will underflow
and incorrectly decide that the original parameter was positive.

This patches fixes the broken condition code so that we handle this
corner case correctly.

Reviewed-by: Steve Capper <steve.capper at arm.com>
Signed-off-by: Will Deacon <will.deacon at arm.com>
---
 arch/arm64/include/asm/atomic_ll_sc.h | 2 +-
 arch/arm64/include/asm/atomic_lse.h   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/atomic_ll_sc.h b/arch/arm64/include/asm/atomic_ll_sc.h
index cbaedf9afb2f..1a9ae9197a9f 100644
--- a/arch/arm64/include/asm/atomic_ll_sc.h
+++ b/arch/arm64/include/asm/atomic_ll_sc.h
@@ -149,7 +149,7 @@ __LL_SC_PREFIX(atomic64_dec_if_positive(atomic64_t *v))
 "	prfm	pstl1strm, %2\n"
 "1:	ldxr	%0, %2\n"
 "	subs	%0, %0, #1\n"
-"	b.mi	2f\n"
+"	b.lt	2f\n"
 "	stlxr	%w1, %0, %2\n"
 "	cbnz	%w1, 1b\n"
 "	dmb	ish\n"
diff --git a/arch/arm64/include/asm/atomic_lse.h b/arch/arm64/include/asm/atomic_lse.h
index b960a547723c..d4b6cb940ee1 100644
--- a/arch/arm64/include/asm/atomic_lse.h
+++ b/arch/arm64/include/asm/atomic_lse.h
@@ -185,7 +185,7 @@ static inline long atomic64_dec_if_positive(atomic64_t *v)
 	/* LSE atomics */
 	"1:	ldr	x30, %[v]\n"
 	"	subs	%[ret], x30, #1\n"
-	"	b.mi	2f\n"
+	"	b.lt	2f\n"
 	"	casal	x30, %[ret], %[v]\n"
 	"	sub	x30, x30, #1\n"
 	"	sub	x30, x30, %[ret]\n"
-- 
2.1.4