SPRN_SPRG_PGDIR is there mainly to speedup SW TLB miss handlers
for powerpc 603.
We need to free SPRN_SPRG2 to reduce the mess with CONFIG_VMAP_STACK.
In hash_page(), reading PGDIR from thread_struct will be in the noise
performance wise.
Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
arch/powerpc/mm/book3s32/hash_low.S | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/mm/book3s32/hash_low.S
b/arch/powerpc/mm/book3s32/hash_low.S
index 48415c857d80..aca353d1c5f4 100644
--- a/arch/powerpc/mm/book3s32/hash_low.S
+++ b/arch/powerpc/mm/book3s32/hash_low.S
@@ -65,13 +65,14 @@ _GLOBAL(hash_page)
/* Get PTE (linux-style) and check access */
lis r0, TASK_SIZE@h /* check if kernel address */
cmplw 0,r4,r0
+ mfspr r8,SPRN_SPRG_THREAD /* current task's THREAD (phys) */
ori r3,r3,_PAGE_USER|_PAGE_PRESENT /* test low addresses as user */
- mfspr r5, SPRN_SPRG_PGDIR /* phys page-table root */
+ lwz r5,PGDIR(r8) /* virt page-table root */
blt+ 112f /* assume user more likely */
- lis r5, (swapper_pg_dir - PAGE_OFFSET)@ha /* if kernel address,
use */
- addi r5 ,r5 ,(swapper_pg_dir - PAGE_OFFSET)@l /* kernel page
table */
+ lis r5,swapper_pg_dir@ha /* if kernel address, use */
+ addi r5,r5,swapper_pg_dir@l /* kernel page table */
rlwimi r3,r9,32-12,29,29 /* MSR_PR -> _PAGE_USER */
-112:
+112: tophys(r5, r5)
#ifndef CONFIG_PTE_64BIT
rlwimi r5,r4,12,20,29 /* insert top 10 bits of address */
lwz r8,0(r5) /* get pmd entry */
--
2.25.0
