[PATCH 7/9] atomic.h : powerpc

[PATCH 7/9] atomic.h : powerpc

[Mathieu Desnoyers]

64 bits cmpxchg, xchg and add_unless for powerpc.


Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>

--- a/include/asm-powerpc/atomic.h
+++ b/include/asm-powerpc/atomic.h
@@ -165,7 +165,8 @@ static __inline__ int atomic_dec_return(
 	return t;
 }
 
-#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
+#define atomic_cmpxchg(v, o, n) \
+	((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
 
 /**
@@ -411,6 +412,44 @@ static __inline__ long atomic64_dec_if_p
 	return t;
 }
 
+#define atomic64_cmpxchg(v, o, n) \
+	((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
+#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
+
+/**
+ * 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;
+}
+
+#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
+
 #endif /* __powerpc64__ */
 
 #include <asm-generic/atomic.h>

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

[Benjamin Herrenschmidt]

> +
> +/**
> + * 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.

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

[Mathieu Desnoyers]

* Benjamin Herrenschmidt (benh@kernel.crashing.org) wrote:
> 
> > +
> > +/**
> > + * 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.
> 
> 

Hi Ben,

It is within a 
#ifdef __powerpc64__
...
#endif /* __powerpc64__ */

so it should only build on 64 bits.

You are right about the PPC405 errata, it seems unnecessary.

The same is true for my asm-powerpc/local.h modification.

Thanks,

Mathieu

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