powerpc/603: Don't handle kernel page TLB misses when not need

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

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 4c2cc42399aa24b5d73be45e9ec82a356020072d..e4338d785a942a6271155e149325e5b0b1602581 100644 (file)
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -498,15 +498,19 @@ 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_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 */