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>
diff --git a/include/asm-sh/thread_info.h b/include/asm-sh/thread_info.h
index 7345350..f64dd80 100644
--- a/include/asm-sh/thread_info.h
+++ b/include/asm-sh/thread_info.h
@@ -48,16 +48,29 @@
#define init_thread_info (init_thread_union.thread_info)
#define init_stack (init_thread_union.stack)
+#define THREAD_SIZE (2*PAGE_SIZE)
+
/* how to get the thread information struct from C */
static inline struct thread_info *current_thread_info(void)
{
struct thread_info *ti;
+#ifdef CONFIG_CPU_HAS_SR_RB
__asm__("stc r7_bank, %0" : "=r" (ti));
+#else
+ unsigned long __dummy;
+
+ __asm__ __volatile__ (
+ "mov r15, %0\n\t"
+ "and %1, %0\n\t"
+ : "=&r" (ti), "=r" (__dummy)
+ : "1" (~(THREAD_SIZE - 1))
+ : "memory");
+#endif
+
return ti;
}
/* thread information allocation */
-#define THREAD_SIZE (2*PAGE_SIZE)
#define alloc_thread_info(ti) ((struct thread_info *) __get_free_pages(GFP_KERNEL,1))
#define free_thread_info(ti) free_pages((unsigned long) (ti), 1)
@@ -65,7 +78,7 @@
/* how to get the thread information struct from ASM */
#define GET_THREAD_INFO(reg) \
- stc r7_bank, reg
+ stc r7_bank, reg
#endif