sh: Fix up T-bit error handling in SH-4A mutex fastpath.

This corrects a deadlock encountered on ap325 in the cases where the
mutex is contended and the slow-path needs to be fallen back upon.

Signed-off-by: Takashi YOSHII <yoshii.takashi@renesas.com>
Signed-off-by: Kuninori Morimoto <morimoto.kuninori@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 9 insertions, 12 deletions

diff --git a/arch/sh/include/asm/mutex-llsc.h b/arch/sh/include/asm/mutex-llsc.h
index ee839ee58ac8..090358a7e1bb 100644
--- a/arch/sh/include/asm/mutex-llsc.h
+++ b/arch/sh/include/asm/mutex-llsc.h
@@ -21,38 +21,36 @@
 static inline void
 __mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
 {
-        int __ex_flag, __res;
+        int __done, __res;
 
         __asm__ __volatile__ (
                 "movli.l        @%2, %0 \n"
                 "add            #-1, %0 \n"
                 "movco.l        %0, @%2 \n"
                 "movt           %1      \n"
-                : "=&z" (__res), "=&r" (__ex_flag)
+                : "=&z" (__res), "=&r" (__done)
                 : "r" (&(count)->counter)
                 : "t");
 
-        __res |= !__ex_flag;
-        if (unlikely(__res != 0))
+        if (unlikely(!__done || __res != 0))
                 fail_fn(count);
 }
 
 static inline int
 __mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *))
 {
-        int __ex_flag, __res;
+        int __done, __res;
 
         __asm__ __volatile__ (
                 "movli.l        @%2, %0 \n"
                 "add            #-1, %0 \n"
                 "movco.l        %0, @%2 \n"
                 "movt           %1      \n"
-                : "=&z" (__res), "=&r" (__ex_flag)
+                : "=&z" (__res), "=&r" (__done)
                 : "r" (&(count)->counter)
                 : "t");
 
-        __res |= !__ex_flag;
-        if (unlikely(__res != 0))
+        if (unlikely(!__done || __res != 0))
                 __res = fail_fn(count);
 
         return __res;
@@ -61,19 +59,18 @@ __mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *))
 static inline void
 __mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
 {
-        int __ex_flag, __res;
+        int __done, __res;
 
         __asm__ __volatile__ (
                 "movli.l        @%2, %0 \n\t"
                 "add            #1, %0  \n\t"
                 "movco.l        %0, @%2 \n\t"
                 "movt           %1      \n\t"
-                : "=&z" (__res), "=&r" (__ex_flag)
+                : "=&z" (__res), "=&r" (__done)
                 : "r" (&(count)->counter)
                 : "t");
 
-        __res |= !__ex_flag;
-        if (unlikely(__res <= 0))
+        if (unlikely(!__done || __res <= 0))
                 fail_fn(count);
 }