arm64: atomics: fix grossly inconsistent asm constraints for exclusives

Our uses of inline asm constraints for atomic operations are fairly
wild and varied. We basically need to guarantee the following:

  1. Any instructions with barrier implications
     (load-acquire/store-release) have a "memory" clobber

  2. When performing exclusive accesses, the addresing mode is generated
     using the "Q" constraint

  3. Atomic blocks which use the condition flags, have a "cc" clobber

This patch addresses these concerns which, as well as fixing the
semantics of the code, stops GCC complaining about impossible asm
constraints.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 66 insertions, 66 deletions

diff --git a/arch/arm64/include/asm/atomic.h b/arch/arm64/include/asm/atomic.h
index 407717ba060e..836364468571 100644
--- a/arch/arm64/include/asm/atomic.h
+++ b/arch/arm64/include/asm/atomic.h
@@ -49,12 +49,12 @@ static inline void atomic_add(int i, atomic_t *v)
 	int result;
 
 	asm volatile("// atomic_add\n"
-"1:	ldxr	%w0, [%3]\n"
-"	add	%w0, %w0, %w4\n"
-"	stxr	%w1, %w0, [%3]\n"
+"1:	ldxr	%w0, %2\n"
+"	add	%w0, %w0, %w3\n"
+"	stxr	%w1, %w0, %2\n"
 "	cbnz	%w1, 1b"
-	: "=&r" (result), "=&r" (tmp), "+o" (v->counter)
-	: "r" (&v->counter), "Ir" (i)
+	: "=&r" (result), "=&r" (tmp), "+Q" (v->counter)
+	: "Ir" (i)
 	: "cc");
 }
 
@@ -64,13 +64,13 @@ static inline int atomic_add_return(int i, atomic_t *v)
 	int result;
 
 	asm volatile("// atomic_add_return\n"
-"1:	ldaxr	%w0, [%3]\n"
-"	add	%w0, %w0, %w4\n"
-"	stlxr	%w1, %w0, [%3]\n"
+"1:	ldaxr	%w0, %2\n"
+"	add	%w0, %w0, %w3\n"
+"	stlxr	%w1, %w0, %2\n"
 "	cbnz	%w1, 1b"
-	: "=&r" (result), "=&r" (tmp), "+o" (v->counter)
-	: "r" (&v->counter), "Ir" (i)
-	: "cc");
+	: "=&r" (result), "=&r" (tmp), "+Q" (v->counter)
+	: "Ir" (i)
+	: "cc", "memory");
 
 	return result;
 }
@@ -81,12 +81,12 @@ static inline void atomic_sub(int i, atomic_t *v)
 	int result;
 
 	asm volatile("// atomic_sub\n"
-"1:	ldxr	%w0, [%3]\n"
-"	sub	%w0, %w0, %w4\n"
-"	stxr	%w1, %w0, [%3]\n"
+"1:	ldxr	%w0, %2\n"
+"	sub	%w0, %w0, %w3\n"
+"	stxr	%w1, %w0, %2\n"
 "	cbnz	%w1, 1b"
-	: "=&r" (result), "=&r" (tmp), "+o" (v->counter)
-	: "r" (&v->counter), "Ir" (i)
+	: "=&r" (result), "=&r" (tmp), "+Q" (v->counter)
+	: "Ir" (i)
 	: "cc");
 }
 
@@ -96,13 +96,13 @@ static inline int atomic_sub_return(int i, atomic_t *v)
 	int result;
 
 	asm volatile("// atomic_sub_return\n"
-"1:	ldaxr	%w0, [%3]\n"
-"	sub	%w0, %w0, %w4\n"
-"	stlxr	%w1, %w0, [%3]\n"
+"1:	ldaxr	%w0, %2\n"
+"	sub	%w0, %w0, %w3\n"
+"	stlxr	%w1, %w0, %2\n"
 "	cbnz	%w1, 1b"
-	: "=&r" (result), "=&r" (tmp), "+o" (v->counter)
-	: "r" (&v->counter), "Ir" (i)
-	: "cc");
+	: "=&r" (result), "=&r" (tmp), "+Q" (v->counter)
+	: "Ir" (i)
+	: "cc", "memory");
 
 	return result;
 }
@@ -113,15 +113,15 @@ static inline int atomic_cmpxchg(atomic_t *ptr, int old, int new)
 	int oldval;
 
 	asm volatile("// atomic_cmpxchg\n"
-"1:	ldaxr	%w1, [%3]\n"
-"	cmp	%w1, %w4\n"
+"1:	ldaxr	%w1, %2\n"
+"	cmp	%w1, %w3\n"
 "	b.ne	2f\n"
-"	stlxr	%w0, %w5, [%3]\n"
+"	stlxr	%w0, %w4, %2\n"
 "	cbnz	%w0, 1b\n"
 "2:"
-	: "=&r" (tmp), "=&r" (oldval), "+o" (ptr->counter)
-	: "r" (&ptr->counter), "Ir" (old), "r" (new)
-	: "cc");
+	: "=&r" (tmp), "=&r" (oldval), "+Q" (ptr->counter)
+	: "Ir" (old), "r" (new)
+	: "cc", "memory");
 
 	return oldval;
 }
@@ -131,12 +131,12 @@ static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
 	unsigned long tmp, tmp2;
 
 	asm volatile("// atomic_clear_mask\n"
-"1:	ldxr	%0, [%3]\n"
-"	bic	%0, %0, %4\n"
-"	stxr	%w1, %0, [%3]\n"
+"1:	ldxr	%0, %2\n"
+"	bic	%0, %0, %3\n"
+"	stxr	%w1, %0, %2\n"
 "	cbnz	%w1, 1b"
-	: "=&r" (tmp), "=&r" (tmp2), "+o" (*addr)
-	: "r" (addr), "Ir" (mask)
+	: "=&r" (tmp), "=&r" (tmp2), "+Q" (*addr)
+	: "Ir" (mask)
 	: "cc");
 }
 
@@ -182,12 +182,12 @@ static inline void atomic64_add(u64 i, atomic64_t *v)
 	unsigned long tmp;
 
 	asm volatile("// atomic64_add\n"
-"1:	ldxr	%0, [%3]\n"
-"	add	%0, %0, %4\n"
-"	stxr	%w1, %0, [%3]\n"
+"1:	ldxr	%0, %2\n"
+"	add	%0, %0, %3\n"
+"	stxr	%w1, %0, %2\n"
 "	cbnz	%w1, 1b"
-	: "=&r" (result), "=&r" (tmp), "+o" (v->counter)
-	: "r" (&v->counter), "Ir" (i)
+	: "=&r" (result), "=&r" (tmp), "+Q" (v->counter)
+	: "Ir" (i)
 	: "cc");
 }
 
@@ -197,13 +197,13 @@ static inline long atomic64_add_return(long i, atomic64_t *v)
 	unsigned long tmp;
 
 	asm volatile("// atomic64_add_return\n"
-"1:	ldaxr	%0, [%3]\n"
-"	add	%0, %0, %4\n"
-"	stlxr	%w1, %0, [%3]\n"
+"1:	ldaxr	%0, %2\n"
+"	add	%0, %0, %3\n"
+"	stlxr	%w1, %0, %2\n"
 "	cbnz	%w1, 1b"
-	: "=&r" (result), "=&r" (tmp), "+o" (v->counter)
-	: "r" (&v->counter), "Ir" (i)
-	: "cc");
+	: "=&r" (result), "=&r" (tmp), "+Q" (v->counter)
+	: "Ir" (i)
+	: "cc", "memory");
 
 	return result;
 }
@@ -214,12 +214,12 @@ static inline void atomic64_sub(u64 i, atomic64_t *v)
 	unsigned long tmp;
 
 	asm volatile("// atomic64_sub\n"
-"1:	ldxr	%0, [%3]\n"
-"	sub	%0, %0, %4\n"
-"	stxr	%w1, %0, [%3]\n"
+"1:	ldxr	%0, %2\n"
+"	sub	%0, %0, %3\n"
+"	stxr	%w1, %0, %2\n"
 "	cbnz	%w1, 1b"
-	: "=&r" (result), "=&r" (tmp), "+o" (v->counter)
-	: "r" (&v->counter), "Ir" (i)
+	: "=&r" (result), "=&r" (tmp), "+Q" (v->counter)
+	: "Ir" (i)
 	: "cc");
 }
 
@@ -229,13 +229,13 @@ static inline long atomic64_sub_return(long i, atomic64_t *v)
 	unsigned long tmp;
 
 	asm volatile("// atomic64_sub_return\n"
-"1:	ldaxr	%0, [%3]\n"
-"	sub	%0, %0, %4\n"
-"	stlxr	%w1, %0, [%3]\n"
+"1:	ldaxr	%0, %2\n"
+"	sub	%0, %0, %3\n"
+"	stlxr	%w1, %0, %2\n"
 "	cbnz	%w1, 1b"
-	: "=&r" (result), "=&r" (tmp), "+o" (v->counter)
-	: "r" (&v->counter), "Ir" (i)
-	: "cc");
+	: "=&r" (result), "=&r" (tmp), "+Q" (v->counter)
+	: "Ir" (i)
+	: "cc", "memory");
 
 	return result;
 }
@@ -246,15 +246,15 @@ static inline long atomic64_cmpxchg(atomic64_t *ptr, long old, long new)
 	unsigned long res;
 
 	asm volatile("// atomic64_cmpxchg\n"
-"1:	ldaxr	%1, [%3]\n"
-"	cmp	%1, %4\n"
+"1:	ldaxr	%1, %2\n"
+"	cmp	%1, %3\n"
 "	b.ne	2f\n"
-"	stlxr	%w0, %5, [%3]\n"
+"	stlxr	%w0, %4, %2\n"
 "	cbnz	%w0, 1b\n"
 "2:"
-	: "=&r" (res), "=&r" (oldval), "+o" (ptr->counter)
-	: "r" (&ptr->counter), "Ir" (old), "r" (new)
-	: "cc");
+	: "=&r" (res), "=&r" (oldval), "+Q" (ptr->counter)
+	: "Ir" (old), "r" (new)
+	: "cc", "memory");
 
 	return oldval;
 }
@@ -267,15 +267,15 @@ static inline long atomic64_dec_if_positive(atomic64_t *v)
 	unsigned long tmp;
 
 	asm volatile("// atomic64_dec_if_positive\n"
-"1:	ldaxr	%0, [%3]\n"
+"1:	ldaxr	%0, %2\n"
 "	subs	%0, %0, #1\n"
 "	b.mi	2f\n"
-"	stlxr	%w1, %0, [%3]\n"
+"	stlxr	%w1, %0, %2\n"
 "	cbnz	%w1, 1b\n"
 "2:"
-	: "=&r" (result), "=&r" (tmp), "+o" (v->counter)
-	: "r" (&v->counter)
-	: "cc");
+	: "=&r" (result), "=&r" (tmp), "+Q" (v->counter)
+	:
+	: "cc", "memory");
 
 	return result;
 }