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powerpc: atomic: Implement acquire/release/relaxed variants for xchg 

Implement xchg{,64}_relaxed and atomic{,64}_xchg_relaxed, based on these
_relaxed variants, release/acquire variants and fully ordered versions
can be built.

Note that xchg{,64}_relaxed and atomic_{,64}_xchg_relaxed are not
compiler barriers.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Boqun Feng 2015-12-15 22:24:16 +08:00 committed by Michael Ellerman
parent dc53617c4a
commit 26760fc19a
2 changed files with 48 additions and 55 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/powerpc/include/asm/atomic.h
View File

@ -177,6 +177,7 @@ static __inline__ int atomic_dec_return_relaxed(atomic_t *v)
#define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
#define atomic_xchg_relaxed(v, new) xchg_relaxed(&((v)->counter), (new))
/**
* __atomic_add_unless - add unless the number is a given value
@ -444,6 +445,7 @@ static __inline__ long atomic64_dec_if_positive(atomic64_t *v)
#define atomic64_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
#define atomic64_xchg_relaxed(v, new) xchg_relaxed(&((v)->counter), (new))
/**
* atomic64_add_unless - add unless the number is a given value

101
arch/powerpc/include/asm/cmpxchg.h
View File

@ -9,34 +9,10 @@
/*
* Atomic exchange
*
* Changes the memory location '*ptr' to be val and returns
* Changes the memory location '*p' to be val and returns
* the previous value stored there.
*/
static __always_inline unsigned long
__xchg_u32(volatile void *p, unsigned long val)
{
unsigned long prev;
__asm__ __volatile__(
PPC_ATOMIC_ENTRY_BARRIER
"1: lwarx %0,0,%2 \n"
PPC405_ERR77(0,%2)
" stwcx. %3,0,%2 \n\
bne- 1b"
PPC_ATOMIC_EXIT_BARRIER
: "=&r" (prev), "+m" (*(volatile unsigned int *)p)
: "r" (p), "r" (val)
: "cc", "memory");
return prev;
}
/*
* Atomic exchange
*
* Changes the memory location '*ptr' to be val and returns
* the previous value stored there.
*/
static __always_inline unsigned long
__xchg_u32_local(volatile void *p, unsigned long val)
{
@ -54,26 +30,24 @@ __xchg_u32_local(volatile void *p, unsigned long val)
return prev;
}
#ifdef CONFIG_PPC64
static __always_inline unsigned long
__xchg_u64(volatile void *p, unsigned long val)
__xchg_u32_relaxed(u32 *p, unsigned long val)
{
unsigned long prev;
__asm__ __volatile__(
PPC_ATOMIC_ENTRY_BARRIER
"1: ldarx %0,0,%2 \n"
PPC405_ERR77(0,%2)
" stdcx. %3,0,%2 \n\
bne- 1b"
PPC_ATOMIC_EXIT_BARRIER
: "=&r" (prev), "+m" (*(volatile unsigned long *)p)
"1: lwarx %0,0,%2\n"
PPC405_ERR77(0, %2)
" stwcx. %3,0,%2\n"
" bne- 1b"
: "=&r" (prev), "+m" (*p)
: "r" (p), "r" (val)
: "cc", "memory");
: "cc");
return prev;
}
#ifdef CONFIG_PPC64
static __always_inline unsigned long
__xchg_u64_local(volatile void *p, unsigned long val)
{
@ -90,6 +64,23 @@ __xchg_u64_local(volatile void *p, unsigned long val)
return prev;
}
static __always_inline unsigned long
__xchg_u64_relaxed(u64 *p, unsigned long val)
{
unsigned long prev;
__asm__ __volatile__(
"1: ldarx %0,0,%2\n"
PPC405_ERR77(0, %2)
" stdcx. %3,0,%2\n"
" bne- 1b"
: "=&r" (prev), "+m" (*p)
: "r" (p), "r" (val)
: "cc");
return prev;
}
#endif
/*
@ -98,21 +89,6 @@ __xchg_u64_local(volatile void *p, unsigned long val)
*/
extern void __xchg_called_with_bad_pointer(void);
static __always_inline unsigned long
__xchg(volatile void *ptr, unsigned long x, unsigned int size)
{
switch (size) {
case 4:
return __xchg_u32(ptr, x);
#ifdef CONFIG_PPC64
case 8:
return __xchg_u64(ptr, x);
#endif
}
__xchg_called_with_bad_pointer();
return x;
}
static __always_inline unsigned long
__xchg_local(volatile void *ptr, unsigned long x, unsigned int size)
{
@ -127,12 +103,21 @@ __xchg_local(volatile void *ptr, unsigned long x, unsigned int size)
__xchg_called_with_bad_pointer();
return x;
}
#define xchg(ptr,x) \
({ \
__typeof__(*(ptr)) _x_ = (x); \
(__typeof__(*(ptr))) __xchg((ptr), (unsigned long)_x_, sizeof(*(ptr))); \
})
static __always_inline unsigned long
__xchg_relaxed(void *ptr, unsigned long x, unsigned int size)
{
switch (size) {
case 4:
return __xchg_u32_relaxed(ptr, x);
#ifdef CONFIG_PPC64
case 8:
return __xchg_u64_relaxed(ptr, x);
#endif
}
__xchg_called_with_bad_pointer();
return x;
}
#define xchg_local(ptr,x) \
({ \
__typeof__(*(ptr)) _x_ = (x); \
@ -140,6 +125,12 @@ __xchg_local(volatile void *ptr, unsigned long x, unsigned int size)
(unsigned long)_x_, sizeof(*(ptr))); \
})
#define xchg_relaxed(ptr, x) \
({ \
__typeof__(*(ptr)) _x_ = (x); \
(__typeof__(*(ptr))) __xchg_relaxed((ptr), \
(unsigned long)_x_, sizeof(*(ptr))); \
})
/*
* Compare and exchange - if *p == old, set it to new,
* and return the old value of *p.