sh: GUSA atomic rollback support.

This implements kernel-level atomic rollback built on top of gUSA,
as an alternative non-IRQ based atomicity method. This is generally
a faster method for platforms that are lacking the LL/SC pairs that
SH-4A and later use, and is only supportable on legacy cores.

Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 5 insertions, 35 deletions

diff --git a/include/asm-sh/system.h b/include/asm-sh/system.h
index ad3d2a636130..969f3d4afe2a 100644
--- a/include/asm-sh/system.h
+++ b/include/asm-sh/system.h
@@ -68,27 +68,11 @@
 
 #define set_mb(var, value) do { (void)xchg(&var, value); } while (0)
 
-static inline unsigned long xchg_u32(volatile u32 *m, unsigned long val)
-{
-        unsigned long flags, retval;
-
-        local_irq_save(flags);
-        retval = *m;
-        *m = val;
-        local_irq_restore(flags);
-        return retval;
-}
-
-static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val)
-{
-        unsigned long flags, retval;
-
-        local_irq_save(flags);
-        retval = *m;
-        *m = val & 0xff;
-        local_irq_restore(flags);
-        return retval;
-}
+#ifdef CONFIG_GUSA_RB
+#include <asm/cmpxchg-grb.h>
+#else
+#include <asm/cmpxchg-irq.h>
+#endif
 
 extern void __xchg_called_with_bad_pointer(void);
 
@@ -115,20 +99,6 @@ extern void __xchg_called_with_bad_pointer(void);
 #define xchg(ptr,x)     \
         ((__typeof__(*(ptr)))__xchg((ptr),(unsigned long)(x), sizeof(*(ptr))))
 
-static inline unsigned long __cmpxchg_u32(volatile int * m, unsigned long old,
-        unsigned long new)
-{
-        __u32 retval;
-        unsigned long flags;
-
-        local_irq_save(flags);
-        retval = *m;
-        if (retval == old)
-                *m = new;
-        local_irq_restore(flags);       /* implies memory barrier  */
-        return retval;
-}
-
 /* This function doesn't exist, so you'll get a linker error
  * if something tries to do an invalid cmpxchg(). */
 extern void __cmpxchg_called_with_bad_pointer(void);