powerpc/85xx: Save scratch registers to thread info instead of using SPRGs.

We expect this is actually faster, and we end up needing more space than we
can get from the SPRGs in some instances.  This is also useful when running
as a guest OS - SPRGs4-7 do not have guest versions.

8 slots are allocated in thread_info for this even though we only actually
use 4 of them - this allows space for future code to have more scratch
space (and we know we'll need it for things like hugetlb).

Signed-off-by: Ashish Kalra <Ashish.Kalra@freescale.com>
Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index d50c2b6d9bc3..eb11a446720e 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -20,6 +20,7 @@
 
 #ifndef __ASSEMBLY__
 #include <linux/compiler.h>
+#include <linux/cache.h>
 #include <asm/ptrace.h>
 #include <asm/types.h>
 
@@ -156,6 +157,10 @@ struct thread_struct {
 #endif
         struct pt_regs  *regs;          /* Pointer to saved register state */
         mm_segment_t    fs;             /* for get_fs() validation */
+#ifdef CONFIG_BOOKE
+        /* BookE base exception scratch space; align on cacheline */
+        unsigned long   normsave[8] ____cacheline_aligned;
+#endif
 #ifdef CONFIG_PPC32
         void            *pgdir;         /* root of page-table tree */
 #endif