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Message-ID: <566af5e87685b1a85d3182549c0d520ce2d8877a.1724173828.git.christophe.leroy@csgroup.eu>
Date: Tue, 20 Aug 2024 19:23:56 +0200
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: CASAUBON Jean Michel <jean-michel.casaubon@...soprasteria.com>,
Michael Ellerman <mpe@...erman.id.au>,
Nicholas Piggin <npiggin@...il.com>,
Naveen N Rao <naveen@...nel.org>
Cc: Christophe Leroy <christophe.leroy@...roup.eu>,
linux-kernel@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH 12/14] powerpc/603: Switch r0 and r3 in TLB miss handlers
In preparation of next patch that will perform some additional
calculations to replace comparison, switch the use of r0 and r3
as r0 has some limitations in some instructions like 'addi/subi'.
Also remove outdated comments about the meaning of each register.
The registers are used for many things and it would be difficult
to accurately describe all things done with a given register. The
function is now small enough to get a global view without much
description.
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
arch/powerpc/kernel/head_book3s_32.S | 94 +++++++++++-----------------
1 file changed, 38 insertions(+), 56 deletions(-)
diff --git a/arch/powerpc/kernel/head_book3s_32.S b/arch/powerpc/kernel/head_book3s_32.S
index 57196883a00e..7995506e7fbd 100644
--- a/arch/powerpc/kernel/head_book3s_32.S
+++ b/arch/powerpc/kernel/head_book3s_32.S
@@ -411,39 +411,33 @@ END_FTR_SECTION_IFSET(CPU_FTR_FPU_UNAVAILABLE)
*/
. = INTERRUPT_INST_TLB_MISS_603
InstructionTLBMiss:
-/*
- * r0: userspace flag (later scratch)
- * r1: linux style pte ( later becomes ppc hardware pte )
- * r2: ptr to linux-style pte
- * r3: fault address
- */
/* Get PTE (linux-style) and check access */
- mfspr r3,SPRN_IMISS
+ mfspr r0,SPRN_IMISS
#ifdef CONFIG_EXECMEM
lis r1, TASK_SIZE@h /* check if kernel address */
- cmplw 0,r1,r3
+ cmplw 0,r1,r0
#endif
mfspr r2, SPRN_SDR1
li r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
rlwinm r2, r2, 28, 0xfffff000
#ifdef CONFIG_EXECMEM
- li r0, 3
+ li r3, 3
bgt- 112f
lis r2, (swapper_pg_dir - PAGE_OFFSET)@ha /* if kernel address, use */
- li r0, 0
+ li r3, 0
addi r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l /* kernel page table */
#endif
-112: rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */
+112: rlwimi r2,r0,12,20,29 /* 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 */
- rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */
+ rlwimi r2,r0,22,20,29 /* insert next 10 bits of address */
lwz r2,0(r2) /* get linux-style pte */
andc. r1,r1,r2 /* check access & ~permission */
bne- InstructionAddressInvalid /* return if access not permitted */
/* Convert linux-style PTE to low word of PPC-style PTE */
#ifdef CONFIG_EXECMEM
- rlwimi r2, r0, 0, 31, 31 /* userspace ? -> PP lsb */
+ rlwimi r2, r3, 0, 31, 31 /* userspace ? -> PP lsb */
#endif
ori r1, r1, 0xe06 /* clear out reserved bits */
andc r1, r2, r1 /* PP = user? 1 : 0 */
@@ -451,7 +445,7 @@ BEGIN_FTR_SECTION
rlwinm r1,r1,0,~_PAGE_COHERENT /* clear M (coherence not required) */
END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
mtspr SPRN_RPA,r1
- tlbli r3
+ tlbli r0
mfspr r3,SPRN_SRR1 /* Need to restore CR0 */
mtcrf 0x80,r3
rfi
@@ -480,35 +474,29 @@ InstructionAddressInvalid:
*/
. = INTERRUPT_DATA_LOAD_TLB_MISS_603
DataLoadTLBMiss:
-/*
- * r0: userspace flag (later scratch)
- * r1: linux style pte ( later becomes ppc hardware pte )
- * r2: ptr to linux-style pte
- * r3: fault address
- */
/* Get PTE (linux-style) and check access */
- mfspr r3,SPRN_DMISS
+ mfspr r0,SPRN_DMISS
lis r1, TASK_SIZE@h /* check if kernel address */
- cmplw 0,r1,r3
+ cmplw 0,r1,r0
mfspr r2, SPRN_SDR1
li r1, _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_READ
rlwinm r2, r2, 28, 0xfffff000
- li r0, 3
+ li r3, 3
bgt- 112f
lis r2, (swapper_pg_dir - PAGE_OFFSET)@ha /* if kernel address, use */
- li r0, 0
+ li r3, 0
addi r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l /* kernel page table */
-112: rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */
+112: rlwimi r2,r0,12,20,29 /* 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 */
- rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */
+ rlwimi r2,r0,22,20,29 /* insert next 10 bits of address */
lwz r2,0(r2) /* get linux-style pte */
andc. r1,r1,r2 /* check access & ~permission */
bne- DataAddressInvalid /* return if access not permitted */
/* Convert linux-style PTE to low word of PPC-style PTE */
rlwinm r1,r2,32-9,30,30 /* _PAGE_WRITE -> PP msb */
- rlwimi r2,r0,0,30,31 /* userspace ? -> PP */
+ rlwimi r2,r3,0,30,31 /* userspace ? -> PP */
rlwimi r1,r2,32-3,24,24 /* _PAGE_WRITE -> _PAGE_DIRTY */
xori r1,r1,_PAGE_DIRTY /* clear dirty when not rw */
ori r1,r1,0xe04 /* clear out reserved bits */
@@ -518,23 +506,23 @@ BEGIN_FTR_SECTION
END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
mtspr SPRN_RPA,r1
BEGIN_MMU_FTR_SECTION
- li r0,1
+ li r3,1
mfspr r1,SPRN_SPRG_603_LRU
- rlwinm r2,r3,20,27,31 /* Get Address bits 15:19 */
- slw r0,r0,r2
- xor r1,r0,r1
- srw r0,r1,r2
+ rlwinm r2,r0,20,27,31 /* Get Address bits 15:19 */
+ slw r3,r3,r2
+ xor r1,r3,r1
+ srw r3,r1,r2
mtspr SPRN_SPRG_603_LRU,r1
mfspr r2,SPRN_SRR1
- rlwimi r2,r0,31-14,14,14
+ rlwimi r2,r3,31-14,14,14
mtspr SPRN_SRR1,r2
mtcrf 0x80,r2
- tlbld r3
+ tlbld r0
rfi
MMU_FTR_SECTION_ELSE
mfspr r2,SPRN_SRR1 /* Need to restore CR0 */
mtcrf 0x80,r2
- tlbld r3
+ tlbld r0
rfi
ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_NEED_DTLB_SW_LRU)
DataAddressInvalid:
@@ -560,34 +548,28 @@ DataAddressInvalid:
*/
. = INTERRUPT_DATA_STORE_TLB_MISS_603
DataStoreTLBMiss:
-/*
- * r0: userspace flag (later scratch)
- * r1: linux style pte ( later becomes ppc hardware pte )
- * r2: ptr to linux-style pte
- * r3: fault address
- */
/* Get PTE (linux-style) and check access */
- mfspr r3,SPRN_DMISS
+ mfspr r0,SPRN_DMISS
lis r1, TASK_SIZE@h /* check if kernel address */
- cmplw 0,r1,r3
+ cmplw 0,r1,r0
mfspr r2, SPRN_SDR1
li r1, _PAGE_RW | _PAGE_DIRTY | _PAGE_PRESENT | _PAGE_ACCESSED
rlwinm r2, r2, 28, 0xfffff000
- li r0, 3
+ li r3, 3
bgt- 112f
lis r2, (swapper_pg_dir - PAGE_OFFSET)@ha /* if kernel address, use */
- li r0, 0
+ li r3, 0
addi r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l /* kernel page table */
-112: rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */
+112: rlwimi r2,r0,12,20,29 /* 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 */
- rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */
+ rlwimi r2,r0,22,20,29 /* insert next 10 bits of address */
lwz r2,0(r2) /* get linux-style pte */
andc. r1,r1,r2 /* check access & ~permission */
bne- DataAddressInvalid /* return if access not permitted */
/* Convert linux-style PTE to low word of PPC-style PTE */
- rlwimi r2,r0,0,31,31 /* userspace ? -> PP lsb */
+ rlwimi r2,r3,0,31,31 /* userspace ? -> PP lsb */
li r1,0xe06 /* clear out reserved bits & PP msb */
andc r1,r2,r1 /* PP = user? 1: 0 */
BEGIN_FTR_SECTION
@@ -597,23 +579,23 @@ END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
mfspr r2,SPRN_SRR1 /* Need to restore CR0 */
mtcrf 0x80,r2
BEGIN_MMU_FTR_SECTION
- li r0,1
+ li r3,1
mfspr r1,SPRN_SPRG_603_LRU
- rlwinm r2,r3,20,27,31 /* Get Address bits 15:19 */
- slw r0,r0,r2
- xor r1,r0,r1
- srw r0,r1,r2
+ rlwinm r2,r0,20,27,31 /* Get Address bits 15:19 */
+ slw r3,r3,r2
+ xor r1,r3,r1
+ srw r3,r1,r2
mtspr SPRN_SPRG_603_LRU,r1
mfspr r2,SPRN_SRR1
- rlwimi r2,r0,31-14,14,14
+ rlwimi r2,r3,31-14,14,14
mtspr SPRN_SRR1,r2
mtcrf 0x80,r2
- tlbld r3
+ tlbld r0
rfi
MMU_FTR_SECTION_ELSE
mfspr r2,SPRN_SRR1 /* Need to restore CR0 */
mtcrf 0x80,r2
- tlbld r3
+ tlbld r0
rfi
ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_NEED_DTLB_SW_LRU)
--
2.44.0
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