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Message-Id: <297f30d8ba75cb0e9ebe0a776d96c19750105570.1550745320.git.christophe.leroy@c-s.fr>
Date: Thu, 21 Feb 2019 10:37:55 +0000 (UTC)
From: Christophe Leroy <christophe.leroy@....fr>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v2 03/10] powerpc/6xx: Store PGDIR physical address in a SPRG
Use SPRN_SPRG2 to store the current thread PGDIR and
avoid reading thread_struct.pgdir at every TLB miss.
Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
arch/powerpc/include/asm/reg.h | 1 +
arch/powerpc/kernel/cpu_setup_6xx.S | 4 ++++
arch/powerpc/kernel/head_32.S | 25 ++++++++++++-------------
arch/powerpc/mm/hash_low_32.S | 3 +--
4 files changed, 18 insertions(+), 15 deletions(-)
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 371ef6e8248e..1f79e1d8fb0b 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -1167,6 +1167,7 @@
#ifdef CONFIG_PPC_BOOK3S_32
#define SPRN_SPRG_SCRATCH0 SPRN_SPRG0
#define SPRN_SPRG_SCRATCH1 SPRN_SPRG1
+#define SPRN_SPRG_PGDIR SPRN_SPRG2
#define SPRN_SPRG_603_LRU SPRN_SPRG4
#endif
diff --git a/arch/powerpc/kernel/cpu_setup_6xx.S b/arch/powerpc/kernel/cpu_setup_6xx.S
index 8c069e96c478..6f1c11e0691f 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_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 04128899a0a5..2b0a26f66115 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -500,16 +500,15 @@ 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_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 */
@@ -574,16 +573,15 @@ 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_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 */
@@ -658,16 +656,15 @@ 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_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 */
@@ -1024,14 +1021,16 @@ _ENTRY(switch_mmu_context)
li r0,NUM_USER_SEGMENTS
mtctr r0
+ lwz r4, MM_PGD(r4)
#ifdef CONFIG_BDI_SWITCH
/* Context switch the PTE pointer for the Abatron BDI2000.
* The PGDIR is passed as second argument.
*/
- lwz r4,MM_PGD(r4)
lis r5, abatron_pteptrs@ha
stw r4, abatron_pteptrs@l + 0x4(r5)
#endif
+ tophys(r4, r4)
+ mtspr SPRN_SPRG_PGDIR, r4
li r4,0
isync
3:
diff --git a/arch/powerpc/mm/hash_low_32.S b/arch/powerpc/mm/hash_low_32.S
index 1e2df3e9f9ea..82e7dd0c0220 100644
--- a/arch/powerpc/mm/hash_low_32.S
+++ b/arch/powerpc/mm/hash_low_32.S
@@ -70,9 +70,8 @@ _GLOBAL(hash_page)
/* Get PTE (linux-style) and check access */
lis r0,KERNELBASE@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 */
- lwz r5,PGDIR(r8) /* virt page-table root */
+ mfspr r5, SPRN_SPRG_PGDIR /* virt page-table root */
blt+ 112f /* assume user more likely */
lis r5,swapper_pg_dir@ha /* if kernel address, use */
addi r5,r5,swapper_pg_dir@l /* kernel page table */
--
2.13.3
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