[PATCH v2] ARM: mm: Fix stage-2 device memory attributes

[marc.zyngier@arm.com (Marc Zyngier)]

On 27/01/14 16:57, Catalin Marinas wrote:
> On Mon, Jan 27, 2014 at 11:16:57AM +0000, Marc Zyngier wrote:
>> On 24/01/14 23:37, Christoffer Dall wrote:
>>> On Sat, Jan 04, 2014 at 08:27:23AM -0800, Christoffer Dall wrote:
>>>> --- a/arch/arm/include/asm/pgtable-3level.h
>>>> +++ b/arch/arm/include/asm/pgtable-3level.h
>>>> @@ -120,13 +120,19 @@
>>>>  /*
>>>>   * 2nd stage PTE definitions for LPAE.
>>>>   */
>>>> -#define L_PTE_S2_MT_UNCACHED	 (_AT(pteval_t, 0x5) << 2) /* MemAttr[3:0] */
>>>> -#define L_PTE_S2_MT_WRITETHROUGH (_AT(pteval_t, 0xa) << 2) /* MemAttr[3:0] */
>>>> -#define L_PTE_S2_MT_WRITEBACK	 (_AT(pteval_t, 0xf) << 2) /* MemAttr[3:0] */
>>>> -#define L_PTE_S2_RDONLY		 (_AT(pteval_t, 1) << 6)   /* HAP[1]   */
>>>> -#define L_PTE_S2_RDWR		 (_AT(pteval_t, 3) << 6)   /* HAP[2:1] */
>>>> -
>>>> -#define L_PMD_S2_RDWR		 (_AT(pmdval_t, 3) << 6)   /* HAP[2:1] */
>>>> +#define L_PTE_S2_MT_UNCACHED		(_AT(pteval_t, 0x0) << 2) /* strongly ordered */
>>>> +#define L_PTE_S2_MT_WRITETHROUGH	(_AT(pteval_t, 0xa) << 2) /* normal inner write-through */
>>>> +#define L_PTE_S2_MT_WRITEBACK		(_AT(pteval_t, 0xf) << 2) /* normal inner write-back */
>>>> +#define L_PTE_S2_MT_DEV_SHARED		(_AT(pteval_t, 0x1) << 2) /* device */
>>>> +#define L_PTE_S2_MT_DEV_NONSHARED	(_AT(pteval_t, 0x1) << 2) /* device */
>>>> +#define L_PTE_S2_MT_DEV_WC		(_AT(pteval_t, 0x5) << 2) /* normal non-cacheable */
>>>> +#define L_PTE_S2_MT_DEV_CACHED		(_AT(pteval_t, 0xf) << 2) /* normal inner write-back */
>>>> +#define L_PTE_S2_MT_MASK		(_AT(pteval_t, 0xf) << 2)
>>>> +
>>>> +#define L_PTE_S2_RDONLY			(_AT(pteval_t, 1) << 6)   /* HAP[1]   */
>>>> +#define L_PTE_S2_RDWR			(_AT(pteval_t, 3) << 6)   /* HAP[2:1] */
>>>> +
>>>> +#define L_PMD_S2_RDWR			(_AT(pmdval_t, 3) << 6)   /* HAP[2:1] */
>>>>  
>>>>  /*
>>>>   * Hyp-mode PL2 PTE definitions for LPAE.
>>
>> The change makes sense to me. arm64 uses a slightly different approach,
>> by using a PTE_S2_MEMATTR macro, but I'm not sure that would work for ARM.
>>
>> Russell, Catalin: could you please have a look at this?
> 
> Do we actually need more than Normal Cacheable and Device for stage 2?

Not so far. As long as these two memory types are enforced as a minimum,
we're quite happy to let the guest use whatever it decides.

I suppose Christoffer introduces them all here as a matter of
completeness, but I don't see them as being useful anytime soon.

	M.
-- 
Jazz is not dead. It just smells funny...