[PATCH v4] [POWERPC] Move to runtime allocated exception stacks

[Paul Mackerras]

Kumar Gala writes:

> For the additonal exception levels (critical, debug, machine check) on
> 40x/book-e we were using "static" allocations of the stack in the
> associated head.S.
> 
> Move to a runtime allocation to make the code a bit easier to read as
> we mimic how we handle IRQ stacks.  Its also a bit easier to setup the
> stack with a "dummy" thread_info in C code.

Looks fine, with just one very minor comment:

> -	addi	r11,r11,THREAD_SIZE;					     \
> -1:	subi	r11,r11,INT_FRAME_SIZE;	/* Allocate an exception frame     */\
> +1:	addi	r11,r11,THREAD_SIZE;					     \
> +	subi	r11,r11,INT_FRAME_SIZE;	/* Allocate an exception frame     */\

You could make that a single addi r11,r11,THREAD_SIZE-INT_FRAME_SIZE
now.

Paul.