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>
diff --git a/arch/sh/include/asm/mutex-llsc.h b/arch/sh/include/asm/mutex-llsc.h
index ee839ee..090358a 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 @@
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);
}
