On 27/03/13 14:11, Catalin Marinas wrote:
> On Tue, Mar 26, 2013 at 05:00:57PM +0000, Marc Zyngier wrote:
>> --- a/arch/arm64/mm/mmu.c
>> +++ b/arch/arm64/mm/mmu.c
>> @@ -44,6 +44,7 @@ struct page *empty_zero_page;
>> EXPORT_SYMBOL(empty_zero_page);
>>
>> pgprot_t pgprot_default;
>> +pgprot_t pgprot_device;
>> EXPORT_SYMBOL(pgprot_default);
>>
>> static pmdval_t prot_sect_kernel;
>> @@ -127,10 +128,11 @@ early_param("cachepolicy", early_cachepolicy);
>> */
>> static void __init init_mem_pgprot(void)
>> {
>> - pteval_t default_pgprot;
>> + pteval_t default_pgprot, device_pgprot;
>> int i;
>>
>> default_pgprot = PTE_ATTRINDX(MT_NORMAL);
>> + device_pgprot = PTE_ATTRINDX(MT_DEVICE_nGnRE) | PTE_PXN | PTE_UXN;
>> prot_sect_kernel = PMD_TYPE_SECT | PMD_SECT_AF | PMD_ATTRINDX(MT_NORMAL);
>>
>> #ifdef CONFIG_SMP
>> @@ -138,6 +140,7 @@ static void __init init_mem_pgprot(void)
>> * Mark memory with the "shared" attribute for SMP systems
>> */
>> default_pgprot |= PTE_SHARED;
>> + device_pgprot |= PTE_SHARED;
>> prot_sect_kernel |= PMD_SECT_S;
>> #endif
>>
>> @@ -147,6 +150,7 @@ static void __init init_mem_pgprot(void)
>> }
>>
>> pgprot_default = __pgprot(PTE_TYPE_PAGE | PTE_AF | default_pgprot);
>> + pgprot_device = __pgprot(PTE_TYPE_PAGE | PTE_AF | device_pgprot);
>> }
>
> I don't think all this pgprot_device addition is needed. According to
> the ARMv8 Translation spec, any shareability attributes for Device
> memory are ignored as the memory is always regarded as Outer Shareable.
> That's why the ioremap() implementation on arm64 only uses pre-defined
> constants.
Right. That makes it much simpler then. I'll drop this part and update
the relevant definitions with PROT_DEVICE_nGnRE instead.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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