linux/arch/powerpc/include/asm/local.h
Paul Mackerras efc3624c94 powerpc: Tell gcc when we clobber the carry in inline asm
We have several instances of inline assembly code that use the addic
or addic. instructions, but don't include XER in the list of clobbers.
The addic and addic. instructions affect the carry bit, which is in
the XER register.

This adds "xer" to the list of clobbers for those inline asm
statements that use addic or addic. and didn't already have it.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-11-19 16:04:28 +11:00

200 lines
4.7 KiB
C

#ifndef _ARCH_POWERPC_LOCAL_H
#define _ARCH_POWERPC_LOCAL_H
#include <linux/percpu.h>
#include <asm/atomic.h>
typedef struct
{
atomic_long_t a;
} local_t;
#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
#define local_read(l) atomic_long_read(&(l)->a)
#define local_set(l,i) atomic_long_set(&(l)->a, (i))
#define local_add(i,l) atomic_long_add((i),(&(l)->a))
#define local_sub(i,l) atomic_long_sub((i),(&(l)->a))
#define local_inc(l) atomic_long_inc(&(l)->a)
#define local_dec(l) atomic_long_dec(&(l)->a)
static __inline__ long local_add_return(long a, local_t *l)
{
long t;
__asm__ __volatile__(
"1:" PPC_LLARX "%0,0,%2 # local_add_return\n\
add %0,%1,%0\n"
PPC405_ERR77(0,%2)
PPC_STLCX "%0,0,%2 \n\
bne- 1b"
: "=&r" (t)
: "r" (a), "r" (&(l->a.counter))
: "cc", "memory");
return t;
}
#define local_add_negative(a, l) (local_add_return((a), (l)) < 0)
static __inline__ long local_sub_return(long a, local_t *l)
{
long t;
__asm__ __volatile__(
"1:" PPC_LLARX "%0,0,%2 # local_sub_return\n\
subf %0,%1,%0\n"
PPC405_ERR77(0,%2)
PPC_STLCX "%0,0,%2 \n\
bne- 1b"
: "=&r" (t)
: "r" (a), "r" (&(l->a.counter))
: "cc", "memory");
return t;
}
static __inline__ long local_inc_return(local_t *l)
{
long t;
__asm__ __volatile__(
"1:" PPC_LLARX "%0,0,%1 # local_inc_return\n\
addic %0,%0,1\n"
PPC405_ERR77(0,%1)
PPC_STLCX "%0,0,%1 \n\
bne- 1b"
: "=&r" (t)
: "r" (&(l->a.counter))
: "cc", "xer", "memory");
return t;
}
/*
* local_inc_and_test - increment and test
* @l: pointer of type local_t
*
* Atomically increments @l by 1
* and returns true if the result is zero, or false for all
* other cases.
*/
#define local_inc_and_test(l) (local_inc_return(l) == 0)
static __inline__ long local_dec_return(local_t *l)
{
long t;
__asm__ __volatile__(
"1:" PPC_LLARX "%0,0,%1 # local_dec_return\n\
addic %0,%0,-1\n"
PPC405_ERR77(0,%1)
PPC_STLCX "%0,0,%1\n\
bne- 1b"
: "=&r" (t)
: "r" (&(l->a.counter))
: "cc", "xer", "memory");
return t;
}
#define local_cmpxchg(l, o, n) \
(cmpxchg_local(&((l)->a.counter), (o), (n)))
#define local_xchg(l, n) (xchg_local(&((l)->a.counter), (n)))
/**
* local_add_unless - add unless the number is a given value
* @l: pointer of type local_t
* @a: the amount to add to v...
* @u: ...unless v is equal to u.
*
* Atomically adds @a to @l, so long as it was not @u.
* Returns non-zero if @l was not @u, and zero otherwise.
*/
static __inline__ int local_add_unless(local_t *l, long a, long u)
{
long t;
__asm__ __volatile__ (
"1:" PPC_LLARX "%0,0,%1 # local_add_unless\n\
cmpw 0,%0,%3 \n\
beq- 2f \n\
add %0,%2,%0 \n"
PPC405_ERR77(0,%2)
PPC_STLCX "%0,0,%1 \n\
bne- 1b \n"
" subf %0,%2,%0 \n\
2:"
: "=&r" (t)
: "r" (&(l->a.counter)), "r" (a), "r" (u)
: "cc", "memory");
return t != u;
}
#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
#define local_sub_and_test(a, l) (local_sub_return((a), (l)) == 0)
#define local_dec_and_test(l) (local_dec_return((l)) == 0)
/*
* Atomically test *l and decrement if it is greater than 0.
* The function returns the old value of *l minus 1.
*/
static __inline__ long local_dec_if_positive(local_t *l)
{
long t;
__asm__ __volatile__(
"1:" PPC_LLARX "%0,0,%1 # local_dec_if_positive\n\
cmpwi %0,1\n\
addi %0,%0,-1\n\
blt- 2f\n"
PPC405_ERR77(0,%1)
PPC_STLCX "%0,0,%1\n\
bne- 1b"
"\n\
2:" : "=&b" (t)
: "r" (&(l->a.counter))
: "cc", "memory");
return t;
}
/* Use these for per-cpu local_t variables: on some archs they are
* much more efficient than these naive implementations. Note they take
* a variable, not an address.
*/
#define __local_inc(l) ((l)->a.counter++)
#define __local_dec(l) ((l)->a.counter++)
#define __local_add(i,l) ((l)->a.counter+=(i))
#define __local_sub(i,l) ((l)->a.counter-=(i))
/* Need to disable preemption for the cpu local counters otherwise we could
still access a variable of a previous CPU in a non atomic way. */
#define cpu_local_wrap_v(l) \
({ local_t res__; \
preempt_disable(); \
res__ = (l); \
preempt_enable(); \
res__; })
#define cpu_local_wrap(l) \
({ preempt_disable(); \
l; \
preempt_enable(); }) \
#define cpu_local_read(l) cpu_local_wrap_v(local_read(&__get_cpu_var(l)))
#define cpu_local_set(l, i) cpu_local_wrap(local_set(&__get_cpu_var(l), (i)))
#define cpu_local_inc(l) cpu_local_wrap(local_inc(&__get_cpu_var(l)))
#define cpu_local_dec(l) cpu_local_wrap(local_dec(&__get_cpu_var(l)))
#define cpu_local_add(i, l) cpu_local_wrap(local_add((i), &__get_cpu_var(l)))
#define cpu_local_sub(i, l) cpu_local_wrap(local_sub((i), &__get_cpu_var(l)))
#define __cpu_local_inc(l) cpu_local_inc(l)
#define __cpu_local_dec(l) cpu_local_dec(l)
#define __cpu_local_add(i, l) cpu_local_add((i), (l))
#define __cpu_local_sub(i, l) cpu_local_sub((i), (l))
#endif /* _ARCH_POWERPC_LOCAL_H */