sh: Cleanup and document register bank usage.

Initial register bank cleanup. Make SR.RB configurable, and add some
preliminary documentation on register bank usage within the kernel.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 16 insertions, 1 deletions

diff --git a/include/asm-sh/system.h b/include/asm-sh/system.h
index 1630a5411e5f..198d17e3069a 100644
--- a/include/asm-sh/system.h
+++ b/include/asm-sh/system.h
@@ -136,7 +136,8 @@ extern void __xchg_called_with_bad_pointer(void);
 #define set_mb(var, value) do { xchg(&var, value); } while (0)
 
 /* Interrupt Control */
-static __inline__ void local_irq_enable(void)
+#ifdef CONFIG_CPU_HAS_SR_RB
+static inline void local_irq_enable(void)
 {
         unsigned long __dummy0, __dummy1;
 
@@ -149,6 +150,20 @@ static __inline__ void local_irq_enable(void)
                              : "1" (~0x000000f0)
                              : "memory");
 }
+#else
+static inline void local_irq_enable(void)
+{
+        unsigned long __dummy0, __dummy1;
+
+        __asm__ __volatile__ (
+                "stc    sr, %0\n\t"
+                "and    %1, %0\n\t"
+                "ldc    %0, sr\n\t"
+                : "=&r" (__dummy0), "=r" (__dummy1)
+                : "1" (~0x000000f0)
+                : "memory");
+}
+#endif
 
 static __inline__ void local_irq_disable(void)
 {