[PATCH v2] printk: Add a short description string to kmsg_dump()

[Michael Ellerman]

Jocelyn Falempe <jfalempe at redhat.com> writes:
> kmsg_dump doesn't forward the panic reason string to the kmsg_dumper
> callback.
> This patch adds a new struct kmsg_dump_detail, that will hold the
> reason and description, and pass it to the dump() callback.
>
> To avoid updating all kmsg_dump() call, it adds a kmsg_dump_desc()
> function and a macro for backward compatibility.
>
> I've written this for drm_panic, but it can be useful for other
> kmsg_dumper.
> It allows to see the panic reason, like "sysrq triggered crash"
> or "VFS: Unable to mount root fs on xxxx" on the drm panic screen.
>
> v2:
>  * Use a struct kmsg_dump_detail to hold the reason and description
>    pointer, for more flexibility if we want to add other parameters.
>    (Kees Cook)
>  * Fix powerpc/nvram_64 build, as I didn't update the forward
>    declaration of oops_to_nvram()
>
> Signed-off-by: Jocelyn Falempe <jfalempe at redhat.com>
> ---
>  arch/powerpc/kernel/nvram_64.c             |  8 ++++----
>  arch/powerpc/platforms/powernv/opal-kmsg.c |  4 ++--

Acked-by: Michael Ellerman <mpe at ellerman.id.au> (powerpc)

cheers