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-rw-r--r--arch/m32r/kernel/sys_m32r.c61
1 files changed, 34 insertions, 27 deletions
diff --git a/arch/m32r/kernel/sys_m32r.c b/arch/m32r/kernel/sys_m32r.c
index fe55b28d372..670cb49210a 100644
--- a/arch/m32r/kernel/sys_m32r.c
+++ b/arch/m32r/kernel/sys_m32r.c
@@ -29,28 +29,7 @@
/*
* sys_tas() - test-and-set
- * linuxthreads testing version
*/
-#ifndef CONFIG_SMP
-asmlinkage int sys_tas(int *addr)
-{
- int oldval;
- unsigned long flags;
-
- if (!access_ok(VERIFY_WRITE, addr, sizeof (int)))
- return -EFAULT;
- local_irq_save(flags);
- oldval = *addr;
- if (!oldval)
- *addr = 1;
- local_irq_restore(flags);
- return oldval;
-}
-#else /* CONFIG_SMP */
-#include <linux/spinlock.h>
-
-static DEFINE_SPINLOCK(tas_lock);
-
asmlinkage int sys_tas(int *addr)
{
int oldval;
@@ -58,15 +37,43 @@ asmlinkage int sys_tas(int *addr)
if (!access_ok(VERIFY_WRITE, addr, sizeof (int)))
return -EFAULT;
- _raw_spin_lock(&tas_lock);
- oldval = *addr;
- if (!oldval)
- *addr = 1;
- _raw_spin_unlock(&tas_lock);
+ /* atomic operation:
+ * oldval = *addr; *addr = 1;
+ */
+ __asm__ __volatile__ (
+ DCACHE_CLEAR("%0", "r4", "%1")
+ " .fillinsn\n"
+ "1:\n"
+ " lock %0, @%1 -> unlock %2, @%1\n"
+ "2:\n"
+ /* NOTE:
+ * The m32r processor can accept interrupts only
+ * at the 32-bit instruction boundary.
+ * So, in the above code, the "unlock" instruction
+ * can be executed continuously after the "lock"
+ * instruction execution without any interruptions.
+ */
+ ".section .fixup,\"ax\"\n"
+ " .balign 4\n"
+ "3: ldi %0, #%3\n"
+ " seth r14, #high(2b)\n"
+ " or3 r14, r14, #low(2b)\n"
+ " jmp r14\n"
+ ".previous\n"
+ ".section __ex_table,\"a\"\n"
+ " .balign 4\n"
+ " .long 1b,3b\n"
+ ".previous\n"
+ : "=&r" (oldval)
+ : "r" (addr), "r" (1), "i"(-EFAULT)
+ : "r14", "memory"
+#ifdef CONFIG_CHIP_M32700_TS1
+ , "r4"
+#endif /* CONFIG_CHIP_M32700_TS1 */
+ );
return oldval;
}
-#endif /* CONFIG_SMP */
/*
* sys_pipe() is the normal C calling standard for creating