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alistair23-linux/arch/powerpc/include/asm/atomic.h
Anton Blanchard a6cf7ed511 powerpc/atomic: Implement atomic*_inc_not_zero 
Implement atomic_inc_not_zero and atomic64_inc_not_zero. At the
moment we use atomic*_add_unless which requires us to put 0 and
1 constants into registers. We can also avoid a subtract by
saving the original value in a second temporary.

This removes 3 instructions from fget:

- c0000000001b63c0:       39 00 00 00     li      r8,0
- c0000000001b63c4:       39 40 00 01     li      r10,1
...
- c0000000001b63e8:       7c 0a 00 50     subf    r0,r10,r0

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-03-07 17:06:08 +11:00

533 lines
10 KiB
C
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#ifndef _ASM_POWERPC_ATOMIC_H_
#define _ASM_POWERPC_ATOMIC_H_
/*
* PowerPC atomic operations
*/
#include <linux/types.h>
#ifdef __KERNEL__
#include <linux/compiler.h>
#include <asm/synch.h>
#include <asm/asm-compat.h>
#include <asm/system.h>
#define ATOMIC_INIT(i) { (i) }
static __inline__ int atomic_read(const atomic_t *v)
{
int t;
__asm__ __volatile__("lwz%U1%X1 %0,%1" : "=r"(t) : "m"(v->counter));
return t;
}
static __inline__ void atomic_set(atomic_t *v, int i)
{
__asm__ __volatile__("stw%U0%X0 %1,%0" : "=m"(v->counter) : "r"(i));
}
static __inline__ void atomic_add(int a, atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%3 # atomic_add\n\
add %0,%2,%0\n"
PPC405_ERR77(0,%3)
" stwcx. %0,0,%3 \n\
bne- 1b"
: "=&r" (t), "+m" (v->counter)
: "r" (a), "r" (&v->counter)
: "cc");
}
static __inline__ int atomic_add_return(int a, atomic_t *v)
{
int t;
__asm__ __volatile__(
PPC_ATOMIC_ENTRY_BARRIER
"1: lwarx %0,0,%2 # atomic_add_return\n\
add %0,%1,%0\n"
PPC405_ERR77(0,%2)
" stwcx. %0,0,%2 \n\
bne- 1b"
PPC_ATOMIC_EXIT_BARRIER
: "=&r" (t)
: "r" (a), "r" (&v->counter)
: "cc", "memory");
return t;
}
#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
static __inline__ void atomic_sub(int a, atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%3 # atomic_sub\n\
subf %0,%2,%0\n"
PPC405_ERR77(0,%3)
" stwcx. %0,0,%3 \n\
bne- 1b"
: "=&r" (t), "+m" (v->counter)
: "r" (a), "r" (&v->counter)
: "cc");
}
static __inline__ int atomic_sub_return(int a, atomic_t *v)
{
int t;
__asm__ __volatile__(
PPC_ATOMIC_ENTRY_BARRIER
"1: lwarx %0,0,%2 # atomic_sub_return\n\
subf %0,%1,%0\n"
PPC405_ERR77(0,%2)
" stwcx. %0,0,%2 \n\
bne- 1b"
PPC_ATOMIC_EXIT_BARRIER
: "=&r" (t)
: "r" (a), "r" (&v->counter)
: "cc", "memory");
return t;
}
static __inline__ void atomic_inc(atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%2 # atomic_inc\n\
addic %0,%0,1\n"
PPC405_ERR77(0,%2)
" stwcx. %0,0,%2 \n\
bne- 1b"
: "=&r" (t), "+m" (v->counter)
: "r" (&v->counter)
: "cc", "xer");
}
static __inline__ int atomic_inc_return(atomic_t *v)
{
int t;
__asm__ __volatile__(
PPC_ATOMIC_ENTRY_BARRIER
"1: lwarx %0,0,%1 # atomic_inc_return\n\
addic %0,%0,1\n"
PPC405_ERR77(0,%1)
" stwcx. %0,0,%1 \n\
bne- 1b"
PPC_ATOMIC_EXIT_BARRIER
: "=&r" (t)
: "r" (&v->counter)
: "cc", "xer", "memory");
return t;
}
/*
* atomic_inc_and_test - increment and test
* @v: pointer of type atomic_t
*
* Atomically increments @v by 1
* and returns true if the result is zero, or false for all
* other cases.
*/
#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
static __inline__ void atomic_dec(atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%2 # atomic_dec\n\
addic %0,%0,-1\n"
PPC405_ERR77(0,%2)\
" stwcx. %0,0,%2\n\
bne- 1b"
: "=&r" (t), "+m" (v->counter)
: "r" (&v->counter)
: "cc", "xer");
}
static __inline__ int atomic_dec_return(atomic_t *v)
{
int t;
__asm__ __volatile__(
PPC_ATOMIC_ENTRY_BARRIER
"1: lwarx %0,0,%1 # atomic_dec_return\n\
addic %0,%0,-1\n"
PPC405_ERR77(0,%1)
" stwcx. %0,0,%1\n\
bne- 1b"
PPC_ATOMIC_EXIT_BARRIER
: "=&r" (t)
: "r" (&v->counter)
: "cc", "xer", "memory");
return t;
}
#define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
/**
* __atomic_add_unless - add unless the number is a given value
* @v: pointer of type atomic_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 the old value of @v.
*/
static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
{
int t;
__asm__ __volatile__ (
PPC_ATOMIC_ENTRY_BARRIER
"1: lwarx %0,0,%1 # __atomic_add_unless\n\
cmpw 0,%0,%3 \n\
beq- 2f \n\
add %0,%2,%0 \n"
PPC405_ERR77(0,%2)
" stwcx. %0,0,%1 \n\
bne- 1b \n"
PPC_ATOMIC_EXIT_BARRIER
" subf %0,%2,%0 \n\
2:"
: "=&r" (t)
: "r" (&v->counter), "r" (a), "r" (u)
: "cc", "memory");
return t;
}
/**
* atomic_inc_not_zero - increment unless the number is zero
* @v: pointer of type atomic_t
*
* Atomically increments @v by 1, so long as @v is non-zero.
* Returns non-zero if @v was non-zero, and zero otherwise.
*/
static __inline__ int atomic_inc_not_zero(atomic_t *v)
{
int t1, t2;
__asm__ __volatile__ (
PPC_ATOMIC_ENTRY_BARRIER
"1: lwarx %0,0,%2 # atomic_inc_not_zero\n\
cmpwi 0,%0,0\n\
beq- 2f\n\
addic %1,%0,1\n"
PPC405_ERR77(0,%2)
" stwcx. %1,0,%2\n\
bne- 1b\n"
PPC_ATOMIC_EXIT_BARRIER
"\n\
2:"
: "=&r" (t1), "=&r" (t2)
: "r" (&v->counter)
: "cc", "xer", "memory");
return t1;
}
#define atomic_inc_not_zero(v) atomic_inc_not_zero((v))
#define atomic_sub_and_test(a, v) (atomic_sub_return((a), (v)) == 0)
#define atomic_dec_and_test(v) (atomic_dec_return((v)) == 0)
/*
* Atomically test *v and decrement if it is greater than 0.
* The function returns the old value of *v minus 1, even if
* the atomic variable, v, was not decremented.
*/
static __inline__ int atomic_dec_if_positive(atomic_t *v)
{
int t;
__asm__ __volatile__(
PPC_ATOMIC_ENTRY_BARRIER
"1: lwarx %0,0,%1 # atomic_dec_if_positive\n\
cmpwi %0,1\n\
addi %0,%0,-1\n\
blt- 2f\n"
PPC405_ERR77(0,%1)
" stwcx. %0,0,%1\n\
bne- 1b"
PPC_ATOMIC_EXIT_BARRIER
"\n\
2:" : "=&b" (t)
: "r" (&v->counter)
: "cc", "memory");
return t;
}
#define smp_mb__before_atomic_dec() smp_mb()
#define smp_mb__after_atomic_dec() smp_mb()
#define smp_mb__before_atomic_inc() smp_mb()
#define smp_mb__after_atomic_inc() smp_mb()
#ifdef __powerpc64__
#define ATOMIC64_INIT(i) { (i) }
static __inline__ long atomic64_read(const atomic64_t *v)
{
long t;
__asm__ __volatile__("ld%U1%X1 %0,%1" : "=r"(t) : "m"(v->counter));
return t;
}
static __inline__ void atomic64_set(atomic64_t *v, long i)
{
__asm__ __volatile__("std%U0%X0 %1,%0" : "=m"(v->counter) : "r"(i));
}
static __inline__ void atomic64_add(long a, atomic64_t *v)
{
long t;
__asm__ __volatile__(
"1: ldarx %0,0,%3 # atomic64_add\n\
add %0,%2,%0\n\
stdcx. %0,0,%3 \n\
bne- 1b"
: "=&r" (t), "+m" (v->counter)
: "r" (a), "r" (&v->counter)
: "cc");
}
static __inline__ long atomic64_add_return(long a, atomic64_t *v)
{
long t;
__asm__ __volatile__(
PPC_ATOMIC_ENTRY_BARRIER
"1: ldarx %0,0,%2 # atomic64_add_return\n\
add %0,%1,%0\n\
stdcx. %0,0,%2 \n\
bne- 1b"
PPC_ATOMIC_EXIT_BARRIER
: "=&r" (t)
: "r" (a), "r" (&v->counter)
: "cc", "memory");
return t;
}
#define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0)
static __inline__ void atomic64_sub(long a, atomic64_t *v)
{
long t;
__asm__ __volatile__(
"1: ldarx %0,0,%3 # atomic64_sub\n\
subf %0,%2,%0\n\
stdcx. %0,0,%3 \n\
bne- 1b"
: "=&r" (t), "+m" (v->counter)
: "r" (a), "r" (&v->counter)
: "cc");
}
static __inline__ long atomic64_sub_return(long a, atomic64_t *v)
{
long t;
__asm__ __volatile__(
PPC_ATOMIC_ENTRY_BARRIER
"1: ldarx %0,0,%2 # atomic64_sub_return\n\
subf %0,%1,%0\n\
stdcx. %0,0,%2 \n\
bne- 1b"
PPC_ATOMIC_EXIT_BARRIER
: "=&r" (t)
: "r" (a), "r" (&v->counter)
: "cc", "memory");
return t;
}
static __inline__ void atomic64_inc(atomic64_t *v)
{
long t;
__asm__ __volatile__(
"1: ldarx %0,0,%2 # atomic64_inc\n\
addic %0,%0,1\n\
stdcx. %0,0,%2 \n\
bne- 1b"
: "=&r" (t), "+m" (v->counter)
: "r" (&v->counter)
: "cc", "xer");
}
static __inline__ long atomic64_inc_return(atomic64_t *v)
{
long t;
__asm__ __volatile__(
PPC_ATOMIC_ENTRY_BARRIER
"1: ldarx %0,0,%1 # atomic64_inc_return\n\
addic %0,%0,1\n\
stdcx. %0,0,%1 \n\
bne- 1b"
PPC_ATOMIC_EXIT_BARRIER
: "=&r" (t)
: "r" (&v->counter)
: "cc", "xer", "memory");
return t;
}
/*
* atomic64_inc_and_test - increment and test
* @v: pointer of type atomic64_t
*
* Atomically increments @v by 1
* and returns true if the result is zero, or false for all
* other cases.
*/
#define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0)
static __inline__ void atomic64_dec(atomic64_t *v)
{
long t;
__asm__ __volatile__(
"1: ldarx %0,0,%2 # atomic64_dec\n\
addic %0,%0,-1\n\
stdcx. %0,0,%2\n\
bne- 1b"
: "=&r" (t), "+m" (v->counter)
: "r" (&v->counter)
: "cc", "xer");
}
static __inline__ long atomic64_dec_return(atomic64_t *v)
{
long t;
__asm__ __volatile__(
PPC_ATOMIC_ENTRY_BARRIER
"1: ldarx %0,0,%1 # atomic64_dec_return\n\
addic %0,%0,-1\n\
stdcx. %0,0,%1\n\
bne- 1b"
PPC_ATOMIC_EXIT_BARRIER
: "=&r" (t)
: "r" (&v->counter)
: "cc", "xer", "memory");
return t;
}
#define atomic64_sub_and_test(a, v) (atomic64_sub_return((a), (v)) == 0)
#define atomic64_dec_and_test(v) (atomic64_dec_return((v)) == 0)
/*
* Atomically test *v and decrement if it is greater than 0.
* The function returns the old value of *v minus 1.
*/
static __inline__ long atomic64_dec_if_positive(atomic64_t *v)
{
long t;
__asm__ __volatile__(
PPC_ATOMIC_ENTRY_BARRIER
"1: ldarx %0,0,%1 # atomic64_dec_if_positive\n\
addic. %0,%0,-1\n\
blt- 2f\n\
stdcx. %0,0,%1\n\
bne- 1b"
PPC_ATOMIC_EXIT_BARRIER
"\n\
2:" : "=&r" (t)
: "r" (&v->counter)
: "cc", "xer", "memory");
return t;
}
#define atomic64_cmpxchg(v, o, n) (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 the old value of @v.
*/
static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
{
long t;
__asm__ __volatile__ (
PPC_ATOMIC_ENTRY_BARRIER
"1: ldarx %0,0,%1 # __atomic_add_unless\n\
cmpd 0,%0,%3 \n\
beq- 2f \n\
add %0,%2,%0 \n"
" stdcx. %0,0,%1 \n\
bne- 1b \n"
PPC_ATOMIC_EXIT_BARRIER
" subf %0,%2,%0 \n\
2:"
: "=&r" (t)
: "r" (&v->counter), "r" (a), "r" (u)
: "cc", "memory");
return t != u;
}
/**
* atomic_inc64_not_zero - increment unless the number is zero
* @v: pointer of type atomic64_t
*
* Atomically increments @v by 1, so long as @v is non-zero.
* Returns non-zero if @v was non-zero, and zero otherwise.
*/
static __inline__ long atomic64_inc_not_zero(atomic64_t *v)
{
long t1, t2;
__asm__ __volatile__ (
PPC_ATOMIC_ENTRY_BARRIER
"1: ldarx %0,0,%2 # atomic64_inc_not_zero\n\
cmpdi 0,%0,0\n\
beq- 2f\n\
addic %1,%0,1\n\
stdcx. %1,0,%2\n\
bne- 1b\n"
PPC_ATOMIC_EXIT_BARRIER
"\n\
2:"
: "=&r" (t1), "=&r" (t2)
: "r" (&v->counter)
: "cc", "xer", "memory");
return t1;
}
#endif /* __powerpc64__ */
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_ATOMIC_H_ */
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