Re: [PATCH 02/10] powerpc/603: Store PGDIR physical address in a SPRG
From: Christophe Leroy
Date: Wed Feb 20 2019 - 12:40:05 EST
Le 25/01/2019 Ã 13:34, Christophe Leroy a ÃcritÂ:
Use SPRN_SPRG5 to store the current thread PGDIR and
avoid reading thread_struct->pgdir at every TLB miss.
I'll send out v2 with an additional patch getting rid of SPRN_SPRG_RTAS
hence freeing SPRN_SPRG2 which I will use here instead of SPRN_SPRG5 so
that all 6xx will benefit.
Christophe
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
---
arch/powerpc/include/asm/reg.h | 1 +
arch/powerpc/kernel/cpu_setup_6xx.S | 4 ++++
arch/powerpc/kernel/head_32.S | 28 ++++++++++++++++------------
3 files changed, 21 insertions(+), 12 deletions(-)
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 1c98ef1f2d5b..ba0ab1a1431b 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -1169,6 +1169,7 @@
#define SPRN_SPRG_SCRATCH1 SPRN_SPRG1
#define SPRN_SPRG_RTAS SPRN_SPRG2
#define SPRN_SPRG_603_LRU SPRN_SPRG4
+#define SPRN_SPRG_603_PGDIR SPRN_SPRG5
#endif
#ifdef CONFIG_40x
diff --git a/arch/powerpc/kernel/cpu_setup_6xx.S b/arch/powerpc/kernel/cpu_setup_6xx.S
index 8c069e96c478..4c91d1f640fe 100644
--- a/arch/powerpc/kernel/cpu_setup_6xx.S
+++ b/arch/powerpc/kernel/cpu_setup_6xx.S
@@ -24,6 +24,10 @@ BEGIN_MMU_FTR_SECTION
li r10,0
mtspr SPRN_SPRG_603_LRU,r10 /* init SW LRU tracking */
END_MMU_FTR_SECTION_IFSET(MMU_FTR_NEED_DTLB_SW_LRU)
+ lis r10, (swapper_pg_dir - PAGE_OFFSET)@h
+ ori r10, r10, (swapper_pg_dir - PAGE_OFFSET)@l
+ mtspr SPRN_SPRG_603_PGDIR, r10
+
BEGIN_FTR_SECTION
bl __init_fpu_registers
END_FTR_SECTION_IFCLR(CPU_FTR_FPU_UNAVAILABLE)
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index c2f564690778..dbd15e03952a 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -502,16 +502,15 @@ InstructionTLBMiss:
mfspr r3,SPRN_IMISS
lis r1,PAGE_OFFSET@h /* check if kernel address */
cmplw 0,r1,r3
- mfspr r2,SPRN_SPRG_THREAD
+ mfspr r2, SPRN_SPRG_603_PGDIR
li r1,_PAGE_USER|_PAGE_PRESENT|_PAGE_EXEC /* low addresses tested as user */
- lwz r2,PGDIR(r2)
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@ha /* if kernel address, use */
addi r2,r2,swapper_pg_dir@l /* kernel page table */
-112: tophys(r2,r2)
- rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */
+ tophys(r2,r2)
+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 */
beq- InstructionAddressInvalid /* return if no mapping */
@@ -576,16 +575,15 @@ DataLoadTLBMiss:
mfspr r3,SPRN_DMISS
lis r1,PAGE_OFFSET@h /* check if kernel address */
cmplw 0,r1,r3
- mfspr r2,SPRN_SPRG_THREAD
+ mfspr r2, SPRN_SPRG_603_PGDIR
li r1,_PAGE_USER|_PAGE_PRESENT /* low addresses tested as user */
- lwz r2,PGDIR(r2)
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@ha /* if kernel address, use */
addi r2,r2,swapper_pg_dir@l /* kernel page table */
-112: tophys(r2,r2)
- rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */
+ tophys(r2,r2)
+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 */
beq- DataAddressInvalid /* return if no mapping */
@@ -660,16 +658,15 @@ DataStoreTLBMiss:
mfspr r3,SPRN_DMISS
lis r1,PAGE_OFFSET@h /* check if kernel address */
cmplw 0,r1,r3
- mfspr r2,SPRN_SPRG_THREAD
+ mfspr r2, SPRN_SPRG_603_PGDIR
li r1,_PAGE_RW|_PAGE_USER|_PAGE_PRESENT /* access flags */
- lwz r2,PGDIR(r2)
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@ha /* if kernel address, use */
addi r2,r2,swapper_pg_dir@l /* kernel page table */
-112: tophys(r2,r2)
- rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */
+ tophys(r2,r2)
+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 */
beq- DataAddressInvalid /* return if no mapping */
@@ -1030,6 +1027,13 @@ _ENTRY(switch_mmu_context)
lis r5, abatron_pteptrs@ha
stw r4, abatron_pteptrs@l + 0x4(r5)
#endif
+BEGIN_MMU_FTR_SECTION
+#ifndef CONFIG_BDI_SWITCH
+ lwz r4, MM_PGD(r4)
+#endif
+ tophys(r4, r4)
+ mtspr SPRN_SPRG_603_PGDIR, r4
+END_MMU_FTR_SECTION_IFCLR(MMU_FTR_HPTE_TABLE)
li r4,0
isync
3: