[PATCH] powerpc/mm: Fix _PAGE_COHERENT support on classic ppc32 HW

Subsystems: linux for powerpc (32-bit and 64-bit), the rest

STALE6429d

3 messages, 3 authors, 2009-02-16 · open the first message on its own page

[PATCH] powerpc/mm: Fix _PAGE_COHERENT support on classic ppc32 HW

From: Kumar Gala <hidden>
Date: 2009-02-10 20:57:56 

The following commit:

commit 64b3d0e8122b422e879b23d42f9e0e8efbbf9744
Author: Benjamin Herrenschmidt [off-list ref]
Date:   Thu Dec 18 19:13:51 2008 +0000

    powerpc/mm: Rework usage of _PAGE_COHERENT/NO_CACHE/GUARDED

broke setting of the _PAGE_COHERENT bit in the PPC HW PTE.  Since we now
actually set _PAGE_COHERENT in the Linux PTE we shouldn't be clearing it
out before we propogate it to the PPC HW PTE.

Reported-by: Martyn Welch <redacted>
Signed-off-by: Kumar Gala <redacted>
---
 arch/powerpc/mm/hash_low_32.S |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/mm/hash_low_32.S b/arch/powerpc/mm/hash_low_32.S
index 67850ec..14af8ce 100644
--- a/arch/powerpc/mm/hash_low_32.S
+++ b/arch/powerpc/mm/hash_low_32.S
@@ -320,7 +320,7 @@ _GLOBAL(create_hpte)
 	and	r8,r8,r0		/* writable if _RW & _DIRTY */
 	rlwimi	r5,r5,32-1,30,30	/* _PAGE_USER -> PP msb */
 	rlwimi	r5,r5,32-2,31,31	/* _PAGE_USER -> PP lsb */
-	ori	r8,r8,0xe14		/* clear out reserved bits and M */
+	ori	r8,r8,0xe04		/* clear out reserved bits */
 	andc	r8,r5,r8		/* PP = user? (rw&dirty? 2: 3): 0 */
 BEGIN_FTR_SECTION
 	rlwinm	r8,r8,0,~_PAGE_COHERENT	/* clear M (coherence not required) */
-- 
1.5.6.6

Re: [PATCH] powerpc/mm: Fix _PAGE_COHERENT support on classic ppc32 HW

From: Becky Bruce <hidden>
Date: 2009-02-10 22:48:17 

On Feb 10, 2009, at 2:57 PM, Kumar Gala wrote:

The following commit:

commit 64b3d0e8122b422e879b23d42f9e0e8efbbf9744
Author: Benjamin Herrenschmidt [off-list ref]
Date:   Thu Dec 18 19:13:51 2008 +0000

   powerpc/mm: Rework usage of _PAGE_COHERENT/NO_CACHE/GUARDED

broke setting of the _PAGE_COHERENT bit in the PPC HW PTE.  Since we  
now
actually set _PAGE_COHERENT in the Linux PTE we shouldn't be  
clearing it
out before we propogate it to the PPC HW PTE.

Reported-by: Martyn Welch <redacted>
Signed-off-by: Kumar Gala <redacted>
I've booted 8641 dual-core and run LTP to completion with an expected  
number of fails.  So....

Acked-by: Becky Bruce <redacted>

-B
quoted hunk
---
arch/powerpc/mm/hash_low_32.S |    2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/mm/hash_low_32.S b/arch/powerpc/mm/ 
hash_low_32.S
index 67850ec..14af8ce 100644
--- a/arch/powerpc/mm/hash_low_32.S
+++ b/arch/powerpc/mm/hash_low_32.S
@@ -320,7 +320,7 @@ _GLOBAL(create_hpte)
	and	r8,r8,r0		/* writable if _RW & _DIRTY */
	rlwimi	r5,r5,32-1,30,30	/* _PAGE_USER -> PP msb */
	rlwimi	r5,r5,32-2,31,31	/* _PAGE_USER -> PP lsb */
-	ori	r8,r8,0xe14		/* clear out reserved bits and M */
+	ori	r8,r8,0xe04		/* clear out reserved bits */
	andc	r8,r5,r8		/* PP = user? (rw&dirty? 2: 3): 0 */
BEGIN_FTR_SECTION
	rlwinm	r8,r8,0,~_PAGE_COHERENT	/* clear M (coherence not required) */
-- 
1.5.6.6

Re: [PATCH] powerpc/mm: Fix _PAGE_COHERENT support on classic ppc32 HW

From: Martyn Welch <hidden>
Date: 2009-02-16 10:10:28 

Kumar Gala wrote:
quoted hunk
The following commit:

commit 64b3d0e8122b422e879b23d42f9e0e8efbbf9744
Author: Benjamin Herrenschmidt [off-list ref]
Date:   Thu Dec 18 19:13:51 2008 +0000

    powerpc/mm: Rework usage of _PAGE_COHERENT/NO_CACHE/GUARDED

broke setting of the _PAGE_COHERENT bit in the PPC HW PTE.  Since we now
actually set _PAGE_COHERENT in the Linux PTE we shouldn't be clearing it
out before we propogate it to the PPC HW PTE.

Reported-by: Martyn Welch <redacted>
Signed-off-by: Kumar Gala <redacted>
---
 arch/powerpc/mm/hash_low_32.S |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/mm/hash_low_32.S b/arch/powerpc/mm/hash_low_32.S
index 67850ec..14af8ce 100644
--- a/arch/powerpc/mm/hash_low_32.S
+++ b/arch/powerpc/mm/hash_low_32.S
@@ -320,7 +320,7 @@ _GLOBAL(create_hpte)
 	and	r8,r8,r0		/* writable if _RW & _DIRTY */
 	rlwimi	r5,r5,32-1,30,30	/* _PAGE_USER -> PP msb */
 	rlwimi	r5,r5,32-2,31,31	/* _PAGE_USER -> PP lsb */
-	ori	r8,r8,0xe14		/* clear out reserved bits and M */
+	ori	r8,r8,0xe04		/* clear out reserved bits */
 	andc	r8,r5,r8		/* PP = user? (rw&dirty? 2: 3): 0 */
 BEGIN_FTR_SECTION
 	rlwinm	r8,r8,0,~_PAGE_COHERENT	/* clear M (coherence not required) */
This does indeed resolve the problem I was having.

Sorry for not replying sooner - bad weather here in the UK unexpectedly extended a planned holiday.

Thank you for resolving this issue,

Martyn

-- 
Martyn Welch MEng MPhil MIET (Principal Software Engineer)   T:+44(0)1327322748
GE Fanuc Intelligent Platforms Ltd,        |Registered in England and Wales
Tove Valley Business Park, Towcester,      |(3828642) at 100 Barbirolli Square,
Northants, NN12 6PF, UK T:+44(0)1327359444 |Manchester,M2 3AB  VAT:GB 729849476
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