Subject: Re: [PATCH 7/9] atomic.h : powerpc

From: Benjamin Herrenschmidt <[email-masked]>
Date: Thu, 21 Dec 2006 14:15:05 +1100

> +
> +/**
> + * atomic64_add_unless - add unless the number is a given value
> + * @v: pointer of type atomic64_t
> + * @a: the amount to add to v...
> + * @u: ...unless v is equal to u.
> + *
> + * Atomically adds @a to @v, so long as it was not @u.
> + * Returns non-zero if @v was not @u, and zero otherwise.
> + */
> +static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
> +{
> +	long t;
> +
> +	__asm__ __volatile__ (
> +	LWSYNC_ON_SMP
> +"1:	ldarx	%0,0,%1		# atomic_add_unless\n\
> +	cmpd	0,%0,%3 \n\
> +	beq-	2f \n\
> +	add	%0,%2,%0 \n"
> +	PPC405_ERR77(0,%2)
> +"	stdcx.	%0,0,%1 \n\
> +	bne-	1b \n"
> +	ISYNC_ON_SMP
> +"	subf	%0,%2,%0 \n\
> +2:"
> +	: "=&r" (t)
> +	: "r" (&v->counter), "r" (a), "r" (u)
> +	: "cc", "memory");
> +
> +	return t != u;
> +}
> +

You shouldn't try to define those when building 32 bits code... Also,
the PPC405 errata, as it's name implies, is specific to 405 cores which
are all 32 bits.

Ben.