Changes in kernel/arch/arm32/include/atomic.h [4702bde:e762b43] in mainline

File:

• kernel/arch/arm32/include/atomic.h (modified) (2 diffs)

kernel/arch/arm32/include/atomic.h

@@ -37 +37 @@
 #define KERN_arm32_ATOMIC_H_
 
-#include <arch/asm.h>
-
 /** Atomic addition.
  *
@@ -49 +47 @@
 static inline long atomic_add(atomic_t *val, int i)
 {
-        long ret;
-
-        /*
-         * This implementation is for UP pre-ARMv6 systems where we do not have
-         * the LDREX and STREX instructions.
-         */
-        ipl_t ipl = interrupts_disable();
-        val->count += i;
-        ret = val->count;
-        interrupts_restore(ipl);
+        int ret;
+        volatile long *mem = &(val->count);
+        
+        asm volatile (
+                "1:\n"
+                        "ldr r2, [%[mem]]\n"
+                        "add r3, r2, %[i]\n"
+                        "str r3, %[ret]\n"
+                        "swp r3, r3, [%[mem]]\n"
+                        "cmp r3, r2\n"
+                        "bne 1b\n"
+                : [ret] "=m" (ret)
+                : [mem] "r" (mem), [i] "r" (i)
+                : "r3", "r2"
+        );
         
         return ret;