[PATCH 05/10] powerpc/603: Don't handle kernel page TLB misses when not need

[Christophe Leroy]

ITLB miss on kernel pages only occur with CONFIG_MODULES and
CONFIG_DEBUG_PAGEALLOC.

Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr>
---
 arch/powerpc/kernel/head_32.S | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 53f65124edd5..3bbf937ad634 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -500,15 +500,19 @@ InstructionTLBMiss:
  */
        /* Get PTE (linux-style) and check access */
        mfspr   r3,SPRN_IMISS
+#if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC)
        lis     r1,PAGE_OFFSET@h                /* check if kernel address */
        cmplw   0,r1,r3
+#endif
        mfspr   r2, SPRN_SPRG_603_PGDIR
        li      r1,_PAGE_USER|_PAGE_PRESENT|_PAGE_EXEC /* low addresses tested 
as user */
+#if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC)
        bge-    112f
        mfspr   r2,SPRN_SRR1            /* and MSR_PR bit from SRR1 */
        rlwimi  r1,r2,32-12,29,29       /* shift MSR_PR to _PAGE_USER posn */
        lis     r2, (swapper_pg_dir - PAGE_OFFSET)@ha   /* if kernel address, 
use */
        addi    r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l        /* kernel page 
table */
+#endif
 112:   rlwimi  r2,r3,12,20,29          /* insert top 10 bits of address */
        lwz     r2,0(r2)                /* get pmd entry */
        rlwinm. r2,r2,0,0,19            /* extract address of pte page */
-- 
2.13.3