* [PATCH 1/3] powerpc/mm: Remove unused register usage in SW TLB miss handling
@ 2009-03-19 13:55 Kumar Gala
2009-03-19 13:55 ` [PATCH 2/3] powerpc/mm: Used free register to save a few cycles " Kumar Gala
0 siblings, 1 reply; 3+ messages in thread
From: Kumar Gala @ 2009-03-19 13:55 UTC (permalink / raw)
Cc: linuxppc-dev
Long ago we had some code that actually used the CTR in the SW TLB
miss handlers (603/e300). Since we don't use it no reason to waste
cycles saving it off and restoring it (we actually didn't restore it
in the fast path case).
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
---
arch/powerpc/kernel/head_32.S | 11 +++--------
1 files changed, 3 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index d794a63..0105fd5 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -472,12 +472,11 @@ SystemCall:
. = 0x1000
InstructionTLBMiss:
/*
- * r0: stored ctr
+ * r0: scratch
* r1: linux style pte ( later becomes ppc hardware pte )
* r2: ptr to linux-style pte
* r3: scratch
*/
- mfctr r0
/* Get PTE (linux-style) and check access */
mfspr r3,SPRN_IMISS
lis r1,PAGE_OFFSET@h /* check if kernel address */
@@ -528,7 +527,6 @@ InstructionAddressInvalid:
addis r1,r1,0x2000
mtspr SPRN_DSISR,r1 /* (shouldn't be needed) */
- mtctr r0 /* Restore CTR */
andi. r2,r3,0xFFFF /* Clear upper bits of SRR1 */
or r2,r2,r1
mtspr SPRN_SRR1,r2
@@ -549,12 +547,11 @@ InstructionAddressInvalid:
. = 0x1100
DataLoadTLBMiss:
/*
- * r0: stored ctr
+ * r0: scratch
* r1: linux style pte ( later becomes ppc hardware pte )
* r2: ptr to linux-style pte
* r3: scratch
*/
- mfctr r0
/* Get PTE (linux-style) and check access */
mfspr r3,SPRN_DMISS
lis r1,PAGE_OFFSET@h /* check if kernel address */
@@ -604,7 +601,6 @@ DataAddressInvalid:
rlwinm r1,r3,9,6,6 /* Get load/store bit */
addis r1,r1,0x2000
mtspr SPRN_DSISR,r1
- mtctr r0 /* Restore CTR */
andi. r2,r3,0xFFFF /* Clear upper bits of SRR1 */
mtspr SPRN_SRR1,r2
mfspr r1,SPRN_DMISS /* Get failing address */
@@ -624,12 +620,11 @@ DataAddressInvalid:
. = 0x1200
DataStoreTLBMiss:
/*
- * r0: stored ctr
+ * r0: scratch
* r1: linux style pte ( later becomes ppc hardware pte )
* r2: ptr to linux-style pte
* r3: scratch
*/
- mfctr r0
/* Get PTE (linux-style) and check access */
mfspr r3,SPRN_DMISS
lis r1,PAGE_OFFSET@h /* check if kernel address */
--
1.5.6.6
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 2/3] powerpc/mm: Used free register to save a few cycles in SW TLB miss handling
2009-03-19 13:55 [PATCH 1/3] powerpc/mm: Remove unused register usage in SW TLB miss handling Kumar Gala
@ 2009-03-19 13:55 ` Kumar Gala
2009-03-19 13:55 ` [PATCH 3/3] powerpc/mm: e300c2/c3/c4 TLB errata workaround Kumar Gala
0 siblings, 1 reply; 3+ messages in thread
From: Kumar Gala @ 2009-03-19 13:55 UTC (permalink / raw)
Cc: linuxppc-dev
Now that r0 is free we can keep the value of I/DMISS in r3 and not reload
it before doing the tlbli/d. This saves us a few cycles in the fast path
case.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
---
arch/powerpc/kernel/head_32.S | 51 +++++++++++++++++++---------------------
1 files changed, 24 insertions(+), 27 deletions(-)
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 0105fd5..8a9dc79 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -495,28 +495,27 @@ InstructionTLBMiss:
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 */
- lwz r3,0(r2) /* get linux-style pte */
- andc. r1,r1,r3 /* check access & ~permission */
+ lwz r0,0(r2) /* get linux-style pte */
+ andc. r1,r1,r0 /* check access & ~permission */
bne- InstructionAddressInvalid /* return if access not permitted */
- ori r3,r3,_PAGE_ACCESSED /* set _PAGE_ACCESSED in pte */
+ ori r0,r0,_PAGE_ACCESSED /* set _PAGE_ACCESSED in pte */
/*
* NOTE! We are assuming this is not an SMP system, otherwise
* we would need to update the pte atomically with lwarx/stwcx.
*/
- stw r3,0(r2) /* update PTE (accessed bit) */
+ stw r0,0(r2) /* update PTE (accessed bit) */
/* Convert linux-style PTE to low word of PPC-style PTE */
- rlwinm r1,r3,32-10,31,31 /* _PAGE_RW -> PP lsb */
- rlwinm r2,r3,32-7,31,31 /* _PAGE_DIRTY -> PP lsb */
+ rlwinm r1,r0,32-10,31,31 /* _PAGE_RW -> PP lsb */
+ rlwinm r2,r0,32-7,31,31 /* _PAGE_DIRTY -> PP lsb */
and r1,r1,r2 /* writable if _RW and _DIRTY */
- rlwimi r3,r3,32-1,30,30 /* _PAGE_USER -> PP msb */
- rlwimi r3,r3,32-1,31,31 /* _PAGE_USER -> PP lsb */
+ rlwimi r0,r0,32-1,30,30 /* _PAGE_USER -> PP msb */
+ rlwimi r0,r0,32-1,31,31 /* _PAGE_USER -> PP lsb */
ori r1,r1,0xe04 /* clear out reserved bits */
- andc r1,r3,r1 /* PP = user? (rw&dirty? 2: 3): 0 */
+ andc r1,r0,r1 /* PP = user? (rw&dirty? 2: 3): 0 */
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
- mfspr r3,SPRN_IMISS
tlbli r3
mfspr r3,SPRN_SRR1 /* Need to restore CR0 */
mtcrf 0x80,r3
@@ -570,28 +569,27 @@ DataLoadTLBMiss:
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 */
- lwz r3,0(r2) /* get linux-style pte */
- andc. r1,r1,r3 /* check access & ~permission */
+ lwz r0,0(r2) /* get linux-style pte */
+ andc. r1,r1,r0 /* check access & ~permission */
bne- DataAddressInvalid /* return if access not permitted */
- ori r3,r3,_PAGE_ACCESSED /* set _PAGE_ACCESSED in pte */
+ ori r0,r0,_PAGE_ACCESSED /* set _PAGE_ACCESSED in pte */
/*
* NOTE! We are assuming this is not an SMP system, otherwise
* we would need to update the pte atomically with lwarx/stwcx.
*/
- stw r3,0(r2) /* update PTE (accessed bit) */
+ stw r0,0(r2) /* update PTE (accessed bit) */
/* Convert linux-style PTE to low word of PPC-style PTE */
- rlwinm r1,r3,32-10,31,31 /* _PAGE_RW -> PP lsb */
- rlwinm r2,r3,32-7,31,31 /* _PAGE_DIRTY -> PP lsb */
+ rlwinm r1,r0,32-10,31,31 /* _PAGE_RW -> PP lsb */
+ rlwinm r2,r0,32-7,31,31 /* _PAGE_DIRTY -> PP lsb */
and r1,r1,r2 /* writable if _RW and _DIRTY */
- rlwimi r3,r3,32-1,30,30 /* _PAGE_USER -> PP msb */
- rlwimi r3,r3,32-1,31,31 /* _PAGE_USER -> PP lsb */
+ rlwimi r0,r0,32-1,30,30 /* _PAGE_USER -> PP msb */
+ rlwimi r0,r0,32-1,31,31 /* _PAGE_USER -> PP lsb */
ori r1,r1,0xe04 /* clear out reserved bits */
- andc r1,r3,r1 /* PP = user? (rw&dirty? 2: 3): 0 */
+ andc r1,r0,r1 /* PP = user? (rw&dirty? 2: 3): 0 */
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
- mfspr r3,SPRN_DMISS
tlbld r3
mfspr r3,SPRN_SRR1 /* Need to restore CR0 */
mtcrf 0x80,r3
@@ -643,24 +641,23 @@ DataStoreTLBMiss:
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 */
- lwz r3,0(r2) /* get linux-style pte */
- andc. r1,r1,r3 /* check access & ~permission */
+ lwz r0,0(r2) /* get linux-style pte */
+ andc. r1,r1,r0 /* check access & ~permission */
bne- DataAddressInvalid /* return if access not permitted */
- ori r3,r3,_PAGE_ACCESSED|_PAGE_DIRTY
+ ori r0,r0,_PAGE_ACCESSED|_PAGE_DIRTY
/*
* NOTE! We are assuming this is not an SMP system, otherwise
* we would need to update the pte atomically with lwarx/stwcx.
*/
- stw r3,0(r2) /* update PTE (accessed/dirty bits) */
+ stw r0,0(r2) /* update PTE (accessed/dirty bits) */
/* Convert linux-style PTE to low word of PPC-style PTE */
- rlwimi r3,r3,32-1,30,30 /* _PAGE_USER -> PP msb */
+ rlwimi r0,r0,32-1,30,30 /* _PAGE_USER -> PP msb */
li r1,0xe05 /* clear out reserved bits & PP lsb */
- andc r1,r3,r1 /* PP = user? 2: 0 */
+ andc r1,r0,r1 /* PP = user? 2: 0 */
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
- mfspr r3,SPRN_DMISS
tlbld r3
mfspr r3,SPRN_SRR1 /* Need to restore CR0 */
mtcrf 0x80,r3
--
1.5.6.6
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 3/3] powerpc/mm: e300c2/c3/c4 TLB errata workaround
2009-03-19 13:55 ` [PATCH 2/3] powerpc/mm: Used free register to save a few cycles " Kumar Gala
@ 2009-03-19 13:55 ` Kumar Gala
0 siblings, 0 replies; 3+ messages in thread
From: Kumar Gala @ 2009-03-19 13:55 UTC (permalink / raw)
Cc: linuxppc-dev
Complete workaround for DTLB errata in e300c2/c3/c4 processors.
Due to the bug, the hardware-implemented LRU algorythm always goes to way
1 of the TLB. This fix implements the proposed software workaround in
form of a LRW table for chosing the TLB-way.
Based on patch from David Jander <david@protonic.nl>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
---
* Fix a linking problem that showed up in testing branch with not having
#include <asm/mmu.h> in cpu_setup_6xx.S for the MMU feature fixup
arch/powerpc/include/asm/mmu.h | 6 ++++++
arch/powerpc/kernel/cpu_setup_6xx.S | 5 +++++
arch/powerpc/kernel/cputable.c | 9 ++++++---
arch/powerpc/kernel/head_32.S | 32 ++++++++++++++++++++++++++++----
4 files changed, 45 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index dc82dcd..c073de4 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h
@@ -46,6 +46,12 @@
*/
#define MMU_FTR_LOCK_BCAST_INVAL ASM_CONST(0x00100000)
+/* This indicates that the processor doesn't handle way selection
+ * properly and needs SW to track and update the LRU state. This
+ * is specific to an errata on e300c2/c3/c4 class parts
+ */
+#define MMU_FTR_NEED_DTLB_SW_LRU ASM_CONST(0x00200000)
+
#ifndef __ASSEMBLY__
#include <asm/cputable.h>
diff --git a/arch/powerpc/kernel/cpu_setup_6xx.S b/arch/powerpc/kernel/cpu_setup_6xx.S
index 72d1d73..54f767e 100644
--- a/arch/powerpc/kernel/cpu_setup_6xx.S
+++ b/arch/powerpc/kernel/cpu_setup_6xx.S
@@ -15,9 +15,14 @@
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/cache.h>
+#include <asm/mmu.h>
_GLOBAL(__setup_cpu_603)
mflr r4
+BEGIN_MMU_FTR_SECTION
+ li r10,0
+ mtspr SPRN_SPRG4,r10 /* init SW LRU tracking */
+END_MMU_FTR_SECTION_IFSET(MMU_FTR_NEED_DTLB_SW_LRU)
BEGIN_FTR_SECTION
bl __init_fpu_registers
END_FTR_SECTION_IFCLR(CPU_FTR_FPU_UNAVAILABLE)
diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index 6388386..4ec0a3a 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -1082,7 +1082,8 @@ static struct cpu_spec __initdata cpu_specs[] = {
.cpu_name = "e300c2",
.cpu_features = CPU_FTRS_E300C2,
.cpu_user_features = PPC_FEATURE_32 | PPC_FEATURE_HAS_MMU,
- .mmu_features = MMU_FTR_USE_HIGH_BATS,
+ .mmu_features = MMU_FTR_USE_HIGH_BATS |
+ MMU_FTR_NEED_DTLB_SW_LRU,
.icache_bsize = 32,
.dcache_bsize = 32,
.cpu_setup = __setup_cpu_603,
@@ -1095,7 +1096,8 @@ static struct cpu_spec __initdata cpu_specs[] = {
.cpu_name = "e300c3",
.cpu_features = CPU_FTRS_E300,
.cpu_user_features = COMMON_USER,
- .mmu_features = MMU_FTR_USE_HIGH_BATS,
+ .mmu_features = MMU_FTR_USE_HIGH_BATS |
+ MMU_FTR_NEED_DTLB_SW_LRU,
.icache_bsize = 32,
.dcache_bsize = 32,
.cpu_setup = __setup_cpu_603,
@@ -1110,7 +1112,8 @@ static struct cpu_spec __initdata cpu_specs[] = {
.cpu_name = "e300c4",
.cpu_features = CPU_FTRS_E300,
.cpu_user_features = COMMON_USER,
- .mmu_features = MMU_FTR_USE_HIGH_BATS,
+ .mmu_features = MMU_FTR_USE_HIGH_BATS |
+ MMU_FTR_NEED_DTLB_SW_LRU,
.icache_bsize = 32,
.dcache_bsize = 32,
.cpu_setup = __setup_cpu_603,
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 8a9dc79..6469ffa 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -590,9 +590,21 @@ 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
+ mfspr r2,SPRN_SRR1 /* Need to restore CR0 */
+ mtcrf 0x80,r2
+BEGIN_MMU_FTR_SECTION
+ li r0,1
+ mfspr r1,SPRN_SPRG4
+ rlwinm r2,r3,20,27,31 /* Get Address bits 15:19 */
+ slw r0,r0,r2
+ xor r1,r0,r1
+ srw r0,r1,r2
+ mtspr SPRN_SPRG4,r1
+ mfspr r2,SPRN_SRR1
+ rlwimi r2,r0,31-14,14,14
+ mtspr SPRN_SRR1,r2
+END_MMU_FTR_SECTION_IFSET(MMU_FTR_NEED_DTLB_SW_LRU)
tlbld r3
- mfspr r3,SPRN_SRR1 /* Need to restore CR0 */
- mtcrf 0x80,r3
rfi
DataAddressInvalid:
mfspr r3,SPRN_SRR1
@@ -658,9 +670,21 @@ 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
+ mfspr r2,SPRN_SRR1 /* Need to restore CR0 */
+ mtcrf 0x80,r2
+BEGIN_MMU_FTR_SECTION
+ li r0,1
+ mfspr r1,SPRN_SPRG4
+ rlwinm r2,r3,20,27,31 /* Get Address bits 15:19 */
+ slw r0,r0,r2
+ xor r1,r0,r1
+ srw r0,r1,r2
+ mtspr SPRN_SPRG4,r1
+ mfspr r2,SPRN_SRR1
+ rlwimi r2,r0,31-14,14,14
+ mtspr SPRN_SRR1,r2
+END_MMU_FTR_SECTION_IFSET(MMU_FTR_NEED_DTLB_SW_LRU)
tlbld r3
- mfspr r3,SPRN_SRR1 /* Need to restore CR0 */
- mtcrf 0x80,r3
rfi
#ifndef CONFIG_ALTIVEC
--
1.5.6.6
^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2009-03-19 13:55 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2009-03-19 13:55 [PATCH 1/3] powerpc/mm: Remove unused register usage in SW TLB miss handling Kumar Gala
2009-03-19 13:55 ` [PATCH 2/3] powerpc/mm: Used free register to save a few cycles " Kumar Gala
2009-03-19 13:55 ` [PATCH 3/3] powerpc/mm: e300c2/c3/c4 TLB errata workaround Kumar Gala
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