[PATCH v2] of: unflatten_and_copy: handle NULL initial_boot_params

[PATCH v2] of: unflatten_and_copy: handle NULL initial_boot_params

[James Hogan]

Check whether initial_boot_params is NULL before dereferencing it in
unflatten_and_copy_device_tree() for the case where no device tree is
available but the arch can still boot to a minimal usable system without
it. In this case also log a warning for when the kernel log buffer is
obtainable.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: devicetree@vger.kernel.org
Cc: linux-arch@vger.kernel.org
---
v2:
 * Log a warning for those who can obtain the kernel log buffer (Grant
   Likely).
---
 drivers/of/fdt.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 2fa024b97c43..758b4f8b30b7 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -922,8 +922,16 @@ void __init unflatten_device_tree(void)
  */
 void __init unflatten_and_copy_device_tree(void)
 {
-	int size = __be32_to_cpu(initial_boot_params->totalsize);
-	void *dt = early_init_dt_alloc_memory_arch(size,
+	int size;
+	void *dt;
+
+	if (!initial_boot_params) {
+		pr_warn("No valid device tree found, continuing without\n");
+		return;
+	}
+
+	size = __be32_to_cpu(initial_boot_params->totalsize);
+	dt = early_init_dt_alloc_memory_arch(size,
 		__alignof__(struct boot_param_header));
 
 	if (dt) {
-- 
1.8.1.2

Re: [PATCH v2] of: unflatten_and_copy: handle NULL initial_boot_params

[James Hogan]

On 21/11/13 13:44, James Hogan wrote:
> Check whether initial_boot_params is NULL before dereferencing it in
> unflatten_and_copy_device_tree() for the case where no device tree is
> available but the arch can still boot to a minimal usable system without
> it. In this case also log a warning for when the kernel log buffer is
> obtainable.
> 
> Signed-off-by: James Hogan <james.hogan@imgtec.com>
> Cc: Grant Likely <grant.likely@linaro.org>
> Cc: Rob Herring <rob.herring@calxeda.com>
> Cc: devicetree@vger.kernel.org
> Cc: linux-arch@vger.kernel.org

Hmm, sorry, I forgot to add Grant's:
Acked-by: Grant Likely <grant.likely@linaro.org>

(from v1)

Cheers
James

> ---
> v2:
>  * Log a warning for those who can obtain the kernel log buffer (Grant
>    Likely).
> ---
>  drivers/of/fdt.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index 2fa024b97c43..758b4f8b30b7 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -922,8 +922,16 @@ void __init unflatten_device_tree(void)
>   */
>  void __init unflatten_and_copy_device_tree(void)
>  {
> -	int size = __be32_to_cpu(initial_boot_params->totalsize);
> -	void *dt = early_init_dt_alloc_memory_arch(size,
> +	int size;
> +	void *dt;
> +
> +	if (!initial_boot_params) {
> +		pr_warn("No valid device tree found, continuing without\n");
> +		return;
> +	}
> +
> +	size = __be32_to_cpu(initial_boot_params->totalsize);
> +	dt = early_init_dt_alloc_memory_arch(size,
>  		__alignof__(struct boot_param_header));
>  
>  	if (dt) {
> 

Re: [PATCH v2] of: unflatten_and_copy: handle NULL initial_boot_params

[Grant Likely]

On Thu, 21 Nov 2013 13:49:51 +0000, James Hogan <james.hogan@imgtec.com> wrote:
> On 21/11/13 13:44, James Hogan wrote:
> > Check whether initial_boot_params is NULL before dereferencing it in
> > unflatten_and_copy_device_tree() for the case where no device tree is
> > available but the arch can still boot to a minimal usable system without
> > it. In this case also log a warning for when the kernel log buffer is
> > obtainable.
> > 
> > Signed-off-by: James Hogan <james.hogan@imgtec.com>
> > Cc: Grant Likely <grant.likely@linaro.org>
> > Cc: Rob Herring <rob.herring@calxeda.com>
> > Cc: devicetree@vger.kernel.org
> > Cc: linux-arch@vger.kernel.org
> 
> Hmm, sorry, I forgot to add Grant's:
> Acked-by: Grant Likely <grant.likely@linaro.org>
> 
> (from v1)

Applied, thanks.

g.