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ppc32/8xx: Fix r3 trashing due to 8MB TLB page instantiation

PATCH In review Jochen Friedrich 3 participants 4 messages Aug 28, 2007 – Aug 30, 2007

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Jochen Friedrich

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#0 lore raw

PATCH 1/1 ppc32/8xx: Fix r3 trashing due to 8MB TLB page instantiation

Instantiation of 8MB pages on the TLB cache for the kernel static mapping trashes r3 register on !CONFIG_8xx_CPU6 configurations. This ensures r3 gets saved and restored.

This has been posted to linuxppc-embedded by Marcelo Tosatti <[email protected]>, but only an incomplete version of the patch has been applied in c51e078f82096a7d35ac8ec2416272e843a0e1c4. This patch adds the rest of the fix.

Signed-off-by Jochen Friedrich <[email protected]>
---
 arch/ppc/kernel/head_8xx.S |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)

This can be pulled from git://git.bocc.de/dbox2.git ppc-fixes

arch/ppc/kernel/head_8xx.S +0 -2
index 944c35c..eb8d26f 100644
@@ -495,9 +495,7 @@ LoadLargeDTLB:
 	lwz	r11, 4(r0)
 
 	lwz	r12, 16(r0)
-#ifdef CONFIG_8xx_CPU6
 	lwz	r3, 8(r0)
-#endif
 	rfi
 
 /* This is the data TLB error on the MPC8xx.  This could be due to
#1 lore raw

Please apply.

Quoted 15 lines · Jochen Friedrich

Instantiation of 8MB pages on the TLB cache for the kernel static mapping trashes r3 register on !CONFIG_8xx_CPU6 configurations. This ensures r3 gets saved and restored.

This has been posted to linuxppc-embedded by Marcelo Tosatti <[email protected]>, but only an incomplete version of the patch has been applied in c51e078f82096a7d35ac8ec2416272e843a0e1c4. This patch adds the rest of the fix.

Signed-off-by Jochen Friedrich <[email protected]>
---
 arch/ppc/kernel/head_8xx.S |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)

This can be pulled from git://git.bocc.de/dbox2.git ppc-fixes

#2 lore raw
In reply to Jochen Friedrich
Quoted 20 lines · Jochen Friedrich

Instantiation of 8MB pages on the TLB cache for the kernel static mapping trashes r3 register on !CONFIG_8xx_CPU6 configurations. This ensures r3 gets saved and restored.

This has been posted to linuxppc-embedded by Marcelo Tosatti <[email protected]>, but only an incomplete version of the patch has been applied in c51e078f82096a7d35ac8ec2416272e843a0e1c4. This patch adds the rest of the fix.

Signed-off-by Jochen Friedrich <[email protected]>
---
 arch/ppc/kernel/head_8xx.S |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)

This can be pulled from git://git.bocc.de/dbox2.git ppc-fixes

arch/ppc/kernel/head_8xx.S +0 -0
index 944c35c..eb8d26f 100644

arch/ppc/kernel/head_8xx.S LoadLargeDTLB: · line 501

Quoted 9 lines
arch/ppc/kernel/head_8xx.S +0 -2
@@ -495,9 +495,7 @@ LoadLargeDTLB:
 	lwz	r11, 4(r0)
 
 	lwz	r12, 16(r0)
-#ifdef CONFIG_8xx_CPU6
 	lwz	r3, 8(r0)
-#endif
 	rfi
 
 /* This is the data TLB error on the MPC8xx.  This could be due to

do we need this in arch/powerpc as well?

- k

author
#3 lore raw

Hi Kumar,

Quoted 1 line

do we need this in arch/powerpc as well?

No. At least not until these patches are applied to powerpc, as well:

8f069b1a90bd97bf6d59a02ecabf0173d9175609 [PATCH] powerpc/8xx: Use 8MB D-TLB's for kernel static mapping faults 3ea4807de7b2c5c903380ba2c2e7150bee942f42 [PATCH] powerpc/8xx: last two 8MB D-TLB entries are incorrectly set c51e078f82096a7d35ac8ec2416272e843a0e1c4 [PATCH] ppc32/8xx: Fix r3 trashing due to 8MB TLB page instantiation

Thanks,
Jochen