[PATCH] ARM: mm: Get rid of L_PTE_USER ref from PAGE_S2_DEVICE

[Christoffer Dall]

On Tue, Apr 23, 2013 at 12:45 AM, Marc Zyngier <marc.zyngier at arm.com> wrote:
> On Mon, 22 Apr 2013 19:17:10 -0700, Christoffer Dall
> <cdall at cs.columbia.edu> wrote:
>> THe L_PTE_USER actually has nothing to do with stage 2 mappings and the
>> L_PTE_S2_RDONLY value sets the readable bit, which was what L_PTE_USER
>> was used for before proper handling of stage 2 memory defines.
>>
>> Signed-off-by: Christoffer Dall <cdall at cs.columbia.edu>
>> ---
>>  arch/arm/include/asm/pgtable.h |    2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/include/asm/pgtable.h
>> b/arch/arm/include/asm/pgtable.h
>> index 80d6fc4..1d1f97f 100644
>> --- a/arch/arm/include/asm/pgtable.h
>> +++ b/arch/arm/include/asm/pgtable.h
>> @@ -88,7 +88,7 @@ extern pgprot_t             pgprot_s2_device;
>>  #define PAGE_HYP             _MOD_PROT(pgprot_kernel, L_PTE_HYP)
>>  #define PAGE_HYP_DEVICE              _MOD_PROT(pgprot_hyp_device, L_PTE_HYP)
>>  #define PAGE_S2                      _MOD_PROT(pgprot_s2, L_PTE_S2_RDONLY)
>> -#define PAGE_S2_DEVICE               _MOD_PROT(pgprot_s2_device, L_PTE_USER |
>> L_PTE_S2_RDONLY)
>> +#define PAGE_S2_DEVICE               _MOD_PROT(pgprot_s2_device, L_PTE_S2_RDONLY)
>>
>>  #define __PAGE_NONE          __pgprot(_L_PTE_DEFAULT | L_PTE_RDONLY | L_PTE_XN
> |
>>  L_PTE_NONE)
>>  #define __PAGE_SHARED                __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_XN)
>
> Good catch.
>
> While we're at it, why not directly set it to be RW instead of RO? The
> only use of PAGE_S2_DEVICE immediately sets the writeable bit anyway.
>

hmm, any potential future uses of read-only device mappings? It seems
"easier" to or on write permissions than remove them, or maybe I'm
imagining things...