From 03d701c2d9b0091cf8e96cb49ab7d2a6a9f19937 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Wed, 25 Nov 2020 07:10:49 +0000 Subject: [PATCH] powerpc/32s: Don't use SPRN_SPRG_PGDIR in hash_page 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 Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/4adca19b7120cdf619956768ed09e74fc6a558f3.1606285014.git.christophe.leroy@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 48415c8..aca353d 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 */ -- 2.7.4