[PATCH] Fix ioremap_cached()/ioremap_wc() for SMP platforms

[Russell King - ARM Linux]

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 at 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
> 
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