* [PATCH] ARM: DT: don't try to access physical address zero
@ 2011-06-09 1:40 Nicolas Pitre
2011-06-09 1:46 ` Grant Likely
0 siblings, 1 reply; 2+ messages in thread
From: Nicolas Pitre @ 2011-06-09 1:40 UTC (permalink / raw)
To: linux-arm-kernel
From: Nicolas Pitre <nicolas.pitre@linaro.org>
If the DT physical address is zero, this is equivalent to no DT.
Especially when the actual RAM physical address is not located at zero,
the result of phys_to_virt() would point to la-la-land and crash the
kernel, which crash is completely silent this early during boot.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
CC: Grant Likely <grant.likely@secretlab.ca>
---
diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
index a701e42..0cdd7b4 100644
--- a/arch/arm/kernel/devtree.c
+++ b/arch/arm/kernel/devtree.c
@@ -76,6 +76,9 @@ struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
unsigned long dt_root;
const char *model;
+ if (!dt_phys)
+ return NULL;
+
devtree = phys_to_virt(dt_phys);
/* check device tree validity */
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH] ARM: DT: don't try to access physical address zero
2011-06-09 1:40 [PATCH] ARM: DT: don't try to access physical address zero Nicolas Pitre
@ 2011-06-09 1:46 ` Grant Likely
0 siblings, 0 replies; 2+ messages in thread
From: Grant Likely @ 2011-06-09 1:46 UTC (permalink / raw)
To: linux-arm-kernel
On Wed, Jun 08, 2011 at 09:40:47PM -0400, Nicolas Pitre wrote:
> From: Nicolas Pitre <nicolas.pitre@linaro.org>
>
> If the DT physical address is zero, this is equivalent to no DT.
> Especially when the actual RAM physical address is not located at zero,
> the result of phys_to_virt() would point to la-la-land and crash the
> kernel, which crash is completely silent this early during boot.
>
> Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
> CC: Grant Likely <grant.likely@secretlab.ca>
Hmmm, I thought I had fixed that.
This is obviously correct.
Acked-by: Grant Likely <grant.likely@secretlab.ca>
> ---
> diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
> index a701e42..0cdd7b4 100644
> --- a/arch/arm/kernel/devtree.c
> +++ b/arch/arm/kernel/devtree.c
> @@ -76,6 +76,9 @@ struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
> unsigned long dt_root;
> const char *model;
>
> + if (!dt_phys)
> + return NULL;
> +
> devtree = phys_to_virt(dt_phys);
>
> /* check device tree validity */
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2011-06-09 1:46 ` Grant Likely
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