From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v1 4/8] powerpc/32s: Don't use SPRN_SPRG_PGDIR in hash_page
Date: Wed, 25 Nov 2020 07:10:49 +0000 (UTC) [thread overview]
Message-ID: <4adca19b7120cdf619956768ed09e74fc6a558f3.1606285014.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <da51f7ec632825a4ce43290a904aad61648408c0.1606285013.git.christophe.leroy@csgroup.eu>
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.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 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
next prev parent reply other threads:[~2020-11-25 7:11 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-25 7:10 [PATCH v1 1/8] powerpc/32s: Always map kernel text and rodata with BATs Christophe Leroy
2020-11-25 7:10 ` [PATCH v1 2/8] powerpc/32s: Don't hash_preload() kernel text Christophe Leroy
2020-11-25 7:10 ` [PATCH v1 3/8] powerpc/32s: Fix an FTR_SECTION_ELSE Christophe Leroy
2020-11-25 7:10 ` Christophe Leroy [this message]
2020-11-25 7:10 ` [PATCH v1 5/8] powerpc/603: Use SPRN_SDR1 to store the pgdir phys address Christophe Leroy
2020-11-25 7:10 ` [PATCH v1 6/8] powerpc/32: Simplify EXCEPTION_PROLOG_1 macro Christophe Leroy
2020-11-25 7:10 ` [PATCH v1 7/8] powerpc/32s: Use SPRN_SPRG_SCRATCH2 in DSI prolog Christophe Leroy
2020-11-25 7:10 ` [PATCH v1 8/8] powerpc/32: Use SPRN_SPRG_SCRATCH2 in exception prologs Christophe Leroy
2020-12-10 11:29 ` [PATCH v1 1/8] powerpc/32s: Always map kernel text and rodata with BATs Michael Ellerman
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