From 0ccc8b7ac86053388e793bad20bd26bd777752eb Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Thu, 20 Mar 2014 08:55:00 +0100 Subject: s390/bitops,atomic: add missing memory barriers When reworking the bitops and atomic ops I missed that those instructions that got atomic behaviour only perform a "specific-operand-serialization" instead of a full "serialization". The compare-and-swap instruction used before performs a full serialization before and after the instruction is executed, which means it has full memory barrier semantics. In order to give the new bitops and atomic ops functions also full memory barrier semantics add a "bcr 14,0" before and after each of those new instructions which performs full serialization as well. This restores memory barrier semantics for bitops and atomic ops functions which return values, like e.g. atomic_add_return(), but not for functions which do not return a value, like e.g. atomic_add(). This is consistent to other architectures and what common code requires. Cc: stable@vger.kernel.org # v3.13+ Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/bitops.h | 41 +++++++++++++++++++++++------------------ 1 file changed, 23 insertions(+), 18 deletions(-) (limited to 'arch/s390/include/asm/bitops.h') diff --git a/arch/s390/include/asm/bitops.h b/arch/s390/include/asm/bitops.h index ec5ef891db6..52054247767 100644 --- a/arch/s390/include/asm/bitops.h +++ b/arch/s390/include/asm/bitops.h @@ -47,14 +47,18 @@ #include #include +#include + +#define __BITOPS_NO_BARRIER "\n" #ifndef CONFIG_64BIT #define __BITOPS_OR "or" #define __BITOPS_AND "nr" #define __BITOPS_XOR "xr" +#define __BITOPS_BARRIER "\n" -#define __BITOPS_LOOP(__addr, __val, __op_string) \ +#define __BITOPS_LOOP(__addr, __val, __op_string, __barrier) \ ({ \ unsigned long __old, __new; \ \ @@ -67,7 +71,7 @@ " jl 0b" \ : "=&d" (__old), "=&d" (__new), "+Q" (*(__addr))\ : "d" (__val) \ - : "cc"); \ + : "cc", "memory"); \ __old; \ }) @@ -78,17 +82,20 @@ #define __BITOPS_OR "laog" #define __BITOPS_AND "lang" #define __BITOPS_XOR "laxg" +#define __BITOPS_BARRIER "bcr 14,0\n" -#define __BITOPS_LOOP(__addr, __val, __op_string) \ +#define __BITOPS_LOOP(__addr, __val, __op_string, __barrier) \ ({ \ unsigned long __old; \ \ typecheck(unsigned long *, (__addr)); \ asm volatile( \ + __barrier \ __op_string " %0,%2,%1\n" \ + __barrier \ : "=d" (__old), "+Q" (*(__addr)) \ : "d" (__val) \ - : "cc"); \ + : "cc", "memory"); \ __old; \ }) @@ -97,8 +104,9 @@ #define __BITOPS_OR "ogr" #define __BITOPS_AND "ngr" #define __BITOPS_XOR "xgr" +#define __BITOPS_BARRIER "\n" -#define __BITOPS_LOOP(__addr, __val, __op_string) \ +#define __BITOPS_LOOP(__addr, __val, __op_string, __barrier) \ ({ \ unsigned long __old, __new; \ \ @@ -111,7 +119,7 @@ " jl 0b" \ : "=&d" (__old), "=&d" (__new), "+Q" (*(__addr))\ : "d" (__val) \ - : "cc"); \ + : "cc", "memory"); \ __old; \ }) @@ -149,12 +157,12 @@ static inline void set_bit(unsigned long nr, volatile unsigned long *ptr) "oi %0,%b1\n" : "+Q" (*caddr) : "i" (1 << (nr & 7)) - : "cc"); + : "cc", "memory"); return; } #endif mask = 1UL << (nr & (BITS_PER_LONG - 1)); - __BITOPS_LOOP(addr, mask, __BITOPS_OR); + __BITOPS_LOOP(addr, mask, __BITOPS_OR, __BITOPS_NO_BARRIER); } static inline void clear_bit(unsigned long nr, volatile unsigned long *ptr) @@ -170,12 +178,12 @@ static inline void clear_bit(unsigned long nr, volatile unsigned long *ptr) "ni %0,%b1\n" : "+Q" (*caddr) : "i" (~(1 << (nr & 7))) - : "cc"); + : "cc", "memory"); return; } #endif mask = ~(1UL << (nr & (BITS_PER_LONG - 1))); - __BITOPS_LOOP(addr, mask, __BITOPS_AND); + __BITOPS_LOOP(addr, mask, __BITOPS_AND, __BITOPS_NO_BARRIER); } static inline void change_bit(unsigned long nr, volatile unsigned long *ptr) @@ -191,12 +199,12 @@ static inline void change_bit(unsigned long nr, volatile unsigned long *ptr) "xi %0,%b1\n" : "+Q" (*caddr) : "i" (1 << (nr & 7)) - : "cc"); + : "cc", "memory"); return; } #endif mask = 1UL << (nr & (BITS_PER_LONG - 1)); - __BITOPS_LOOP(addr, mask, __BITOPS_XOR); + __BITOPS_LOOP(addr, mask, __BITOPS_XOR, __BITOPS_NO_BARRIER); } static inline int @@ -206,8 +214,7 @@ test_and_set_bit(unsigned long nr, volatile unsigned long *ptr) unsigned long old, mask; mask = 1UL << (nr & (BITS_PER_LONG - 1)); - old = __BITOPS_LOOP(addr, mask, __BITOPS_OR); - barrier(); + old = __BITOPS_LOOP(addr, mask, __BITOPS_OR, __BITOPS_BARRIER); return (old & mask) != 0; } @@ -218,8 +225,7 @@ test_and_clear_bit(unsigned long nr, volatile unsigned long *ptr) unsigned long old, mask; mask = ~(1UL << (nr & (BITS_PER_LONG - 1))); - old = __BITOPS_LOOP(addr, mask, __BITOPS_AND); - barrier(); + old = __BITOPS_LOOP(addr, mask, __BITOPS_AND, __BITOPS_BARRIER); return (old & ~mask) != 0; } @@ -230,8 +236,7 @@ test_and_change_bit(unsigned long nr, volatile unsigned long *ptr) unsigned long old, mask; mask = 1UL << (nr & (BITS_PER_LONG - 1)); - old = __BITOPS_LOOP(addr, mask, __BITOPS_XOR); - barrier(); + old = __BITOPS_LOOP(addr, mask, __BITOPS_XOR, __BITOPS_BARRIER); return (old & mask) != 0; } -- cgit v1.2.3-70-g09d2