kexec, x86: fix kexec when boot_params.hardware_subarch != 0

Simon Horman <horms@...> writes:

>
> On Tue, Mar 29, 2011 at 09:04:53AM +0000, WANG Cong wrote:
> > 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.
>
> Do you think it would be better for the code to loop through
> a few common alternatives for the path?
>

Not fully tested, but instead of looping through possible mount points maybe
look through mtab in search of debugfs by fs type.

Something like this?

kexec, x86: search for debugfs mountpoint in /etc/mtab

From: Chris Leech <christopher.leech@linux.intel.com>

Signed-off-by: Chris Leech <christopher.leech@linux.intel.com>
Signed-off-by: Simon Horman <horms@verge.net.au>

0 files changed, 0 insertions, 0 deletions