[PATCH v2 1/3] powerpc/nvram: move generic code for nvram and pstore

[Michael Ellerman]

On Tue, 2014-12-16 at 23:35 +0530, Hari Bathini wrote:
> With minor checks, we can move most of the code for nvram
> under pseries to a common place to be re-used by other
> powerpc platforms like powernv. This patch moves such
> common code to arch/powerpc/kernel/nvram_64.c file.

Sharing the code is great.

But, you need to keep in mind that it is very common for us to build kernels
with both POWERNV=y and PSERIES=y.

So you need to make sure you're only using CONFIG_PPC_PSERIES to protect things
that are optional on pseries. Not things that we *shouldn't* be doing on
powernv.

For example the logic in nvram_init_oops_partition() looks like it might do the
wrong thing for PSERIES=y POWERNV=y.

> diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
> index b390f55..a033fe9 100644
> --- a/arch/powerpc/include/asm/rtas.h
> +++ b/arch/powerpc/include/asm/rtas.h
> @@ -343,6 +343,8 @@ extern int early_init_dt_scan_rtas(unsigned long node,
>  extern void pSeries_log_error(char *buf, unsigned int err_type, int fatal);
>  
>  #ifdef CONFIG_PPC_PSERIES
> +extern unsigned long last_rtas_event;
> +extern int clobbering_unread_rtas_event(void);

You should add an empty version of this for !PSERIES, so you don't have to
ifdef all the call sites.

cheers