[PATCH v2] ARM: vector_table: Fix creation of second level page table

[PATCH v2] ARM: vector_table: Fix creation of second level page table

[Sascha Hauer]

The second level page tables can only start at a 1MiB section boundary,
so instead of calling arm_create_pte() with the high vector address
(which is 0xffff0000, not 1MiB aligned) we have to call it with
0xfff00000 to correctly create a second level page table.
The old values broke SoCs which have peripherals in the upper 1MiB
area, like for example the Atmel AT91RM9200. On these Socs we correctly
created the vector page, but the pages around it did not have a 1:1
mapping anymore which led to unreachable peripherals.

Fixes: f6b77fe9: ARM: Rework vector table setup

Reported-by: Peter Kardos <kardos.peter.sk@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---

Changes since v1:
- Use ALIGN_DOWN instead of open coded alignment
- more clear commit message

 arch/arm/cpu/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/cpu/mmu.c b/arch/arm/cpu/mmu.c
index a31bce4..459abe5 100644
--- a/arch/arm/cpu/mmu.c
+++ b/arch/arm/cpu/mmu.c
@@ -307,7 +307,7 @@ static void create_vector_table(unsigned long adr)
 		vectors = xmemalign(PAGE_SIZE, PAGE_SIZE);
 		pr_debug("Creating vector table, virt = 0x%p, phys = 0x%08lx\n",
 			 vectors, adr);
-		exc = arm_create_pte(adr);
+		exc = arm_create_pte(ALIGN_DOWN(adr, SZ_1M));
 		idx = (adr & (SZ_1M - 1)) >> PAGE_SHIFT;
 		exc[idx] = (u32)vectors | PTE_TYPE_SMALL | pte_flags_cached;
 	}
-- 
2.8.1


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Re: [PATCH v2] ARM: vector_table: Fix creation of second level page table

[Peter Kardos]

Tested this one as well  with my AT91RM9200 system, v2016.08 + patch; 
The system starts/boots as expected.
If no one objects, we can consider this issue closed/fixed.

Peter

On 8/25/2016 8:36 AM, Sascha Hauer wrote:
> The second level page tables can only start at a 1MiB section boundary,
> so instead of calling arm_create_pte() with the high vector address
> (which is 0xffff0000, not 1MiB aligned) we have to call it with
> 0xfff00000 to correctly create a second level page table.
> The old values broke SoCs which have peripherals in the upper 1MiB
> area, like for example the Atmel AT91RM9200. On these Socs we correctly
> created the vector page, but the pages around it did not have a 1:1
> mapping anymore which led to unreachable peripherals.
>
> Fixes: f6b77fe9: ARM: Rework vector table setup
>
> Reported-by: Peter Kardos <kardos.peter.sk@gmail.com>
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>
> Changes since v1:
> - Use ALIGN_DOWN instead of open coded alignment
> - more clear commit message
>
>   arch/arm/cpu/mmu.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/cpu/mmu.c b/arch/arm/cpu/mmu.c
> index a31bce4..459abe5 100644
> --- a/arch/arm/cpu/mmu.c
> +++ b/arch/arm/cpu/mmu.c
> @@ -307,7 +307,7 @@ static void create_vector_table(unsigned long adr)
>   		vectors = xmemalign(PAGE_SIZE, PAGE_SIZE);
>   		pr_debug("Creating vector table, virt = 0x%p, phys = 0x%08lx\n",
>   			 vectors, adr);
> -		exc = arm_create_pte(adr);
> +		exc = arm_create_pte(ALIGN_DOWN(adr, SZ_1M));
>   		idx = (adr & (SZ_1M - 1)) >> PAGE_SHIFT;
>   		exc[idx] = (u32)vectors | PTE_TYPE_SMALL | pte_flags_cached;
>   	}


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Re: [PATCH v2] ARM: vector_table: Fix creation of second level page table

[Sascha Hauer]

On Thu, Aug 25, 2016 at 11:32:43PM +0200, Peter Kardos wrote:
> Tested this one as well  with my AT91RM9200 system, v2016.08 + patch; The
> system starts/boots as expected.
> If no one objects, we can consider this issue closed/fixed.

I took this as a
Tested-by: Peter Kardos <kardos.peter.sk@gmail.com>

Thanks for testing.

Sascha

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Re: [PATCH v2] ARM: vector_table: Fix creation of second level page table

[Peter Kardos]

Thanks for the fix.

Peter

On 8/26/2016 7:45 AM, Sascha Hauer wrote:
> On Thu, Aug 25, 2016 at 11:32:43PM +0200, Peter Kardos wrote:
>> Tested this one as well  with my AT91RM9200 system, v2016.08 + patch; The
>> system starts/boots as expected.
>> If no one objects, we can consider this issue closed/fixed.
> I took this as a
> Tested-by: Peter Kardos <kardos.peter.sk@gmail.com>
>
> Thanks for testing.
>
> Sascha
>


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