From: John David Anglin dave.anglin@bell.net
commit e96ebd589debd9a6a793608c4ec7019c38785dea upstream.
This patch implements the __smp_store_release and __smp_load_acquire barriers using ordered stores and loads. This avoids the sync instruction present in the generic implementation.
Cc: stable@vger.kernel.org # 4.14+ Signed-off-by: Dave Anglin dave.anglin@bell.net Signed-off-by: Helge Deller deller@gmx.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- arch/parisc/include/asm/barrier.h | 61 +++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+)
diff --git a/arch/parisc/include/asm/barrier.h b/arch/parisc/include/asm/barrier.h index dbaaca84f27f3..640d46edf32e7 100644 --- a/arch/parisc/include/asm/barrier.h +++ b/arch/parisc/include/asm/barrier.h @@ -26,6 +26,67 @@ #define __smp_rmb() mb() #define __smp_wmb() mb()
+#define __smp_store_release(p, v) \ +do { \ + typeof(p) __p = (p); \ + union { typeof(*p) __val; char __c[1]; } __u = \ + { .__val = (__force typeof(*p)) (v) }; \ + compiletime_assert_atomic_type(*p); \ + switch (sizeof(*p)) { \ + case 1: \ + asm volatile("stb,ma %0,0(%1)" \ + : : "r"(*(__u8 *)__u.__c), "r"(__p) \ + : "memory"); \ + break; \ + case 2: \ + asm volatile("sth,ma %0,0(%1)" \ + : : "r"(*(__u16 *)__u.__c), "r"(__p) \ + : "memory"); \ + break; \ + case 4: \ + asm volatile("stw,ma %0,0(%1)" \ + : : "r"(*(__u32 *)__u.__c), "r"(__p) \ + : "memory"); \ + break; \ + case 8: \ + if (IS_ENABLED(CONFIG_64BIT)) \ + asm volatile("std,ma %0,0(%1)" \ + : : "r"(*(__u64 *)__u.__c), "r"(__p) \ + : "memory"); \ + break; \ + } \ +} while (0) + +#define __smp_load_acquire(p) \ +({ \ + union { typeof(*p) __val; char __c[1]; } __u; \ + typeof(p) __p = (p); \ + compiletime_assert_atomic_type(*p); \ + switch (sizeof(*p)) { \ + case 1: \ + asm volatile("ldb,ma 0(%1),%0" \ + : "=r"(*(__u8 *)__u.__c) : "r"(__p) \ + : "memory"); \ + break; \ + case 2: \ + asm volatile("ldh,ma 0(%1),%0" \ + : "=r"(*(__u16 *)__u.__c) : "r"(__p) \ + : "memory"); \ + break; \ + case 4: \ + asm volatile("ldw,ma 0(%1),%0" \ + : "=r"(*(__u32 *)__u.__c) : "r"(__p) \ + : "memory"); \ + break; \ + case 8: \ + if (IS_ENABLED(CONFIG_64BIT)) \ + asm volatile("ldd,ma 0(%1),%0" \ + : "=r"(*(__u64 *)__u.__c) : "r"(__p) \ + : "memory"); \ + break; \ + } \ + __u.__val; \ +}) #include <asm-generic/barrier.h>
#endif /* !__ASSEMBLY__ */