1 files changed, 19 insertions, 0 deletions

diff --git a/arch/arc/include/asm/bitops.h b/arch/arc/include/asm/bitops.h
index 4051e9525939..624a9d048ca9 100644
--- a/arch/arc/include/asm/bitops.h
+++ b/arch/arc/include/asm/bitops.h
@@ -117,6 +117,12 @@ static inline int test_and_set_bit(unsigned long nr, volatile unsigned long *m)
         if (__builtin_constant_p(nr))
                 nr &= 0x1f;
 
+        /*
+         * Explicit full memory barrier needed before/after as
+         * LLOCK/SCOND themselves don't provide any such semantics
+         */
+        smp_mb();
+
         __asm__ __volatile__(
         "1:     llock   %0, [%2]        \n"
         "       bset    %1, %0, %3      \n"
@@ -126,6 +132,8 @@ static inline int test_and_set_bit(unsigned long nr, volatile unsigned long *m)
         : "r"(m), "ir"(nr)
         : "cc");
 
+        smp_mb();
+
         return (old & (1 << nr)) != 0;
 }
 
@@ -139,6 +147,8 @@ test_and_clear_bit(unsigned long nr, volatile unsigned long *m)
         if (__builtin_constant_p(nr))
                 nr &= 0x1f;
 
+        smp_mb();
+
         __asm__ __volatile__(
         "1:     llock   %0, [%2]        \n"
         "       bclr    %1, %0, %3      \n"
@@ -148,6 +158,8 @@ test_and_clear_bit(unsigned long nr, volatile unsigned long *m)
         : "r"(m), "ir"(nr)
         : "cc");
 
+        smp_mb();
+
         return (old & (1 << nr)) != 0;
 }
 
@@ -161,6 +173,8 @@ test_and_change_bit(unsigned long nr, volatile unsigned long *m)
         if (__builtin_constant_p(nr))
                 nr &= 0x1f;
 
+        smp_mb();
+
         __asm__ __volatile__(
         "1:     llock   %0, [%2]        \n"
         "       bxor    %1, %0, %3      \n"
@@ -170,6 +184,8 @@ test_and_change_bit(unsigned long nr, volatile unsigned long *m)
         : "r"(m), "ir"(nr)
         : "cc");
 
+        smp_mb();
+
         return (old & (1 << nr)) != 0;
 }
 
@@ -249,6 +265,9 @@ static inline int test_and_set_bit(unsigned long nr, volatile unsigned long *m)
         if (__builtin_constant_p(nr))
                 nr &= 0x1f;
 
+        /*
+         * spin lock/unlock provide the needed smp_mb() before/after
+         */
         bitops_lock(flags);
 
         old = *m;