* [PATCH] ARM: mm: Get rid of L_PTE_USER ref from PAGE_S2_DEVICE
@ 2013-04-23 2:17 Christoffer Dall
2013-04-23 7:45 ` Marc Zyngier
0 siblings, 1 reply; 3+ messages in thread
From: Christoffer Dall @ 2013-04-23 2:17 UTC (permalink / raw)
To: linux-arm-kernel
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@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)
--
1.7.10.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH] ARM: mm: Get rid of L_PTE_USER ref from PAGE_S2_DEVICE
2013-04-23 2:17 [PATCH] ARM: mm: Get rid of L_PTE_USER ref from PAGE_S2_DEVICE Christoffer Dall
@ 2013-04-23 7:45 ` Marc Zyngier
2013-04-23 15:02 ` Christoffer Dall
0 siblings, 1 reply; 3+ messages in thread
From: Marc Zyngier @ 2013-04-23 7:45 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, 22 Apr 2013 19:17:10 -0700, Christoffer Dall
<cdall@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@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.
M.
--
Fast, cheap, reliable. Pick two.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] ARM: mm: Get rid of L_PTE_USER ref from PAGE_S2_DEVICE
2013-04-23 7:45 ` Marc Zyngier
@ 2013-04-23 15:02 ` Christoffer Dall
0 siblings, 0 replies; 3+ messages in thread
From: Christoffer Dall @ 2013-04-23 15:02 UTC (permalink / raw)
To: linux-arm-kernel
On Tue, Apr 23, 2013 at 12:45 AM, Marc Zyngier <marc.zyngier@arm.com> wrote:
> On Mon, 22 Apr 2013 19:17:10 -0700, Christoffer Dall
> <cdall@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@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...
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-04-23 2:17 [PATCH] ARM: mm: Get rid of L_PTE_USER ref from PAGE_S2_DEVICE Christoffer Dall
2013-04-23 7:45 ` Marc Zyngier
2013-04-23 15:02 ` Christoffer Dall
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