[PATCH v2 4/5] powerpc/pmem/of_pmem: Update of_pmem to use the new barrier instruction.

[Aneesh Kumar K.V]

of_pmem on POWER10 can now use phwsync instead of hwsync to ensure
all previous writes are architecturally visible for the platform
buffer flush.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.ibm.com>
---
 arch/powerpc/include/asm/cacheflush.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/powerpc/include/asm/cacheflush.h b/arch/powerpc/include/asm/cacheflush.h
index e92191b390f3..f22057dc9dd0 100644
--- a/arch/powerpc/include/asm/cacheflush.h
+++ b/arch/powerpc/include/asm/cacheflush.h
@@ -119,6 +119,16 @@ static inline void invalidate_dcache_range(unsigned long start,
 #define copy_from_user_page(vma, page, vaddr, dst, src, len) \
 	memcpy(dst, src, len)
 
+
+#define arch_pmem_flush_barrier arch_pmem_flush_barrier
+static inline void  arch_pmem_flush_barrier(void)
+{
+	if (cpu_has_feature(CPU_FTR_ARCH_31))
+		asm volatile(PPC_PHWSYNC ::: "memory");
+	else
+		asm volatile("hwsync" ::: "memory");
+}
+
 #endif /* __KERNEL__ */
 
 #endif /* _ASM_POWERPC_CACHEFLUSH_H */
-- 
2.26.2