* [PATCH] Fix ioremap_cached()/ioremap_wc() for SMP platforms
@ 2010-04-08 9:38 Russell King - ARM Linux
2010-04-09 13:47 ` Russell King - ARM Linux
0 siblings, 1 reply; 3+ messages in thread
From: Russell King - ARM Linux @ 2010-04-08 9:38 UTC (permalink / raw)
To: linux-arm-kernel
Write combining/cached device mappings are not setting the shared bit,
which could potentially cause problems on SMP systems since the cache
lines won't participate in the cache coherency protocol.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
--
This doesn't make it any more legal to use ioremap*() on main system
RAM than it was before this change; it does mean that ioremap_wc()
regions are correctly marked as shared which happens to agree with
the main system RAM mappings. Strictly to the arch. spec. for ARMv6+,
it remains "unpredictable" to use ioremap*() on main system RAM.
arch/arm/mm/mmu.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 9d4da6a..4223d08 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -420,6 +420,10 @@ static void __init build_mem_type_table(void)
user_pgprot |= L_PTE_SHARED;
kern_pgprot |= L_PTE_SHARED;
vecs_pgprot |= L_PTE_SHARED;
+ mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_S;
+ mem_types[MT_DEVICE_WC].prot_pte |= L_PTE_SHARED;
+ mem_types[MT_DEVICE_CACHED].prot_sect |= PMD_SECT_S;
+ mem_types[MT_DEVICE_CACHED].prot_pte |= L_PTE_SHARED;
mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S;
mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_S;
#endif
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH] Fix ioremap_cached()/ioremap_wc() for SMP platforms
2010-04-08 9:38 [PATCH] Fix ioremap_cached()/ioremap_wc() for SMP platforms Russell King - ARM Linux
@ 2010-04-09 13:47 ` Russell King - ARM Linux
2010-04-09 13:57 ` Shilimkar, Santosh
0 siblings, 1 reply; 3+ messages in thread
From: Russell King - ARM Linux @ 2010-04-09 13:47 UTC (permalink / raw)
To: linux-arm-kernel
Santosh,
Any chance of checking this please? This should result in the query
about the OMAP framebuffer mappings sharedness being resolved.
Thanks.
On Thu, Apr 08, 2010 at 10:38:52AM +0100, Russell King - ARM Linux wrote:
> Write combining/cached device mappings are not setting the shared bit,
> which could potentially cause problems on SMP systems since the cache
> lines won't participate in the cache coherency protocol.
>
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> --
> This doesn't make it any more legal to use ioremap*() on main system
> RAM than it was before this change; it does mean that ioremap_wc()
> regions are correctly marked as shared which happens to agree with
> the main system RAM mappings. Strictly to the arch. spec. for ARMv6+,
> it remains "unpredictable" to use ioremap*() on main system RAM.
>
> arch/arm/mm/mmu.c | 4 ++++
> 1 files changed, 4 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
> index 9d4da6a..4223d08 100644
> --- a/arch/arm/mm/mmu.c
> +++ b/arch/arm/mm/mmu.c
> @@ -420,6 +420,10 @@ static void __init build_mem_type_table(void)
> user_pgprot |= L_PTE_SHARED;
> kern_pgprot |= L_PTE_SHARED;
> vecs_pgprot |= L_PTE_SHARED;
> + mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_S;
> + mem_types[MT_DEVICE_WC].prot_pte |= L_PTE_SHARED;
> + mem_types[MT_DEVICE_CACHED].prot_sect |= PMD_SECT_S;
> + mem_types[MT_DEVICE_CACHED].prot_pte |= L_PTE_SHARED;
> mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S;
> mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_S;
> #endif
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] Fix ioremap_cached()/ioremap_wc() for SMP platforms
2010-04-09 13:47 ` Russell King - ARM Linux
@ 2010-04-09 13:57 ` Shilimkar, Santosh
0 siblings, 0 replies; 3+ messages in thread
From: Shilimkar, Santosh @ 2010-04-09 13:57 UTC (permalink / raw)
To: linux-arm-kernel
> -----Original Message-----
> From: Russell King - ARM Linux [mailto:linux at arm.linux.org.uk]
> Sent: Friday, April 09, 2010 7:17 PM
> To: Shilimkar, Santosh
> Cc: linux-arm-kernel at lists.infradead.org
> Subject: Re: [PATCH] Fix ioremap_cached()/ioremap_wc() for SMP platforms
>
> Santosh,
>
> Any chance of checking this please? This should result in the query
> about the OMAP framebuffer mappings sharedness being resolved.
>
Oh Yes. I tested this and it does fix the "shared" bit issue of frame buffer
>
> On Thu, Apr 08, 2010 at 10:38:52AM +0100, Russell King - ARM Linux wrote:
> > Write combining/cached device mappings are not setting the shared bit,
> > which could potentially cause problems on SMP systems since the cache
> > lines won't participate in the cache coherency protocol.
> >
> > Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> > --
> > This doesn't make it any more legal to use ioremap*() on main system
> > RAM than it was before this change; it does mean that ioremap_wc()
> > regions are correctly marked as shared which happens to agree with
> > the main system RAM mappings. Strictly to the arch. spec. for ARMv6+,
> > it remains "unpredictable" to use ioremap*() on main system RAM.
> >
> > arch/arm/mm/mmu.c | 4 ++++
> > 1 files changed, 4 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
> > index 9d4da6a..4223d08 100644
> > --- a/arch/arm/mm/mmu.c
> > +++ b/arch/arm/mm/mmu.c
> > @@ -420,6 +420,10 @@ static void __init build_mem_type_table(void)
> > user_pgprot |= L_PTE_SHARED;
> > kern_pgprot |= L_PTE_SHARED;
> > vecs_pgprot |= L_PTE_SHARED;
> > + mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_S;
> > + mem_types[MT_DEVICE_WC].prot_pte |= L_PTE_SHARED;
> > + mem_types[MT_DEVICE_CACHED].prot_sect |= PMD_SECT_S;
> > + mem_types[MT_DEVICE_CACHED].prot_pte |= L_PTE_SHARED;
> > mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S;
> > mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_S;
> > #endif
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 3+ messages in thread
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2010-04-08 9:38 [PATCH] Fix ioremap_cached()/ioremap_wc() for SMP platforms Russell King - ARM Linux
2010-04-09 13:47 ` Russell King - ARM Linux
2010-04-09 13:57 ` Shilimkar, Santosh
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