[PATCH v4 6/6] powerpc: implement smp_cond_load_relaxed
From: Nicholas Piggin
Date: Fri Jul 24 2020 - 09:15:18 EST
This implements smp_cond_load_relaed with the slowpath busy loop using the
preferred SMT priority pattern.
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
arch/powerpc/include/asm/barrier.h | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/arch/powerpc/include/asm/barrier.h b/arch/powerpc/include/asm/barrier.h
index 123adcefd40f..9b4671d38674 100644
--- a/arch/powerpc/include/asm/barrier.h
+++ b/arch/powerpc/include/asm/barrier.h
@@ -76,6 +76,20 @@ do { \
___p1; \
})
+#define smp_cond_load_relaxed(ptr, cond_expr) ({ \
+ typeof(ptr) __PTR = (ptr); \
+ __unqual_scalar_typeof(*ptr) VAL; \
+ VAL = READ_ONCE(*__PTR); \
+ if (unlikely(!(cond_expr))) { \
+ spin_begin(); \
+ do { \
+ VAL = READ_ONCE(*__PTR); \
+ } while (!(cond_expr)); \
+ spin_end(); \
+ } \
+ (typeof(*ptr))VAL; \
+})
+
#ifdef CONFIG_PPC_BOOK3S_64
#define NOSPEC_BARRIER_SLOT nop
#elif defined(CONFIG_PPC_FSL_BOOK3E)
--
2.23.0