[PATCH V2] kexec, x86: fix kexec when boot_params.hardware_subarch != 0

[WANG Cong]

On Mon, 28 Mar 2011 14:50:11 -0700, Chris Leech wrote:

> kexec needs to keep the subarch setting the same as the running kernel
> in the boot parameters, or the kernel will die in early setup.  I ran
> into this with X86_SUBARCH_MRST, but it should apply to CE4100 and any
> future subarch that uses non-default early setup code.
> 
> This patch requires debugfs mounted at /sys/kernel/debug, as that's the
> only way I know of to get at the running kernels boot_params. Without
> debugfs mounted it falls back to the current behavior of assuming
> subarch 0.
> 
...
>  
> +#define BOOT_PARAMS_DBGFS	"/sys/kernel/debug/boot_params/data"

A minor issue here is that you are using a hard-coded debugfs path,
debugfs can be also mounted to /debug too, so it is better that if we can 
search the path dynamically here.

Thanks.