[PATCH] powerpc/64: Initialise thread_info for emergency stacks

[Michael Ellerman]

Nicholas Piggin <npiggin at gmail.com> writes:

> diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
> index a941cc6fc3e9..5995e4b2996d 100644
> --- a/arch/powerpc/include/asm/thread_info.h
> +++ b/arch/powerpc/include/asm/thread_info.h
> @@ -62,6 +63,24 @@ struct thread_info {
>  
>  #define THREAD_SIZE_ORDER	(THREAD_SHIFT - PAGE_SHIFT)
>  
> +/*
> + * Emergency stacks are used for a range of things, from asynchronous
> + * NMIs (system reset, machine check) to synchronous, process context.
> + * Set HARDIRQ_OFFSET because we don't know exactly what context we
> + * come from or if it had a valid stack, which is about the best we
> + * can do.
> + * TODO: what to do with accounting?
> + */
> +#define emstack_init_thread_info(ti, c)		\
> +do {						\
> +	(ti)->task = NULL;			\
> +	(ti)->cpu = (c);			\
> +	(ti)->preempt_count = HARDIRQ_OFFSET;	\
> +	(ti)->local_flags = 0;			\
> +	(ti)->flags = 0;			\
> +	klp_init_thread_info(ti);		\
> +} while (0)

Why don't we just bzero() the whole thing? Like we do for the other
stacks?

cheers