Changeset bb3ba51 in mainline

Timestamp:

2017-08-22T18:10:29Z (7 years ago)

Author:

Martin Decky <martin@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

295ee02

Parents:

b93ea46a

Message:

riscv64: atomic operations

File:

• kernel/arch/riscv64/include/arch/atomic.h (modified) (1 diff)

kernel/arch/riscv64/include/arch/atomic.h

@@ -40 +40 @@
 NO_TRACE static inline void atomic_inc(atomic_t *val)
 {
-        // FIXME
+        asm volatile (
+                "amoadd.d zero, %[inc], %[addr]\n"
+                : [addr] "+A" (val->count)
+                : [inc] "r" (1)
+        );
 }
 
 NO_TRACE static inline void atomic_dec(atomic_t *val)
 {
-        // FIXME
+        asm volatile (
+                "amoadd.d zero, %[inc], %[addr]\n"
+                : [addr] "+A" (val->count)
+                : [inc] "r" (-1)
+        );
 }
 
 NO_TRACE static inline atomic_count_t atomic_postinc(atomic_t *val)
 {
-        atomic_inc(val);
-        return val->count - 1;
+        atomic_count_t orig;
+        
+        asm volatile (
+                "amoadd.d %[orig], %[inc], %[addr]\n"
+                : [orig] "=r" (orig), [addr] "+A" (val->count)
+                : [inc] "r" (1)
+        );
+        
+        return orig;
 }
 
 NO_TRACE static inline atomic_count_t atomic_postdec(atomic_t *val)
 {
-        atomic_dec(val);
-        return val->count + 1;
+        atomic_count_t orig;
+        
+        asm volatile (
+                "amoadd.d %[orig], %[inc], %[addr]\n"
+                : [orig] "=r" (orig), [addr] "+A" (val->count)
+                : [inc] "r" (-1)
+        );
+        
+        return orig;
 }
 
 NO_TRACE static inline atomic_count_t atomic_preinc(atomic_t *val)
 {
-        atomic_inc(val);
-        return val->count;
+        atomic_count_t orig;
+        
+        asm volatile (
+                "amoadd.d %[orig], %[inc], %[addr]\n"
+                : [orig] "=r" (orig), [addr] "+A" (val->count)
+                : [inc] "r" (1)
+        );
+        
+        return orig - 1;
 }
 
 NO_TRACE static inline atomic_count_t atomic_predec(atomic_t *val)
 {
-        atomic_dec(val);
-        return val->count;
+        atomic_count_t orig;
+        
+        asm volatile (
+                "amoadd.d %[orig], %[inc], %[addr]\n"
+                : [orig] "=r" (orig), [addr] "+A" (val->count)
+                : [inc] "r" (-1)
+        );
+        
+        return orig + 1;
 }