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fd2efaa4eb
linux_dsm_epyc7002/arch/powerpc/include/asm/atomic.h
Mark Rutland fd2efaa4eb locking/atomics: Rework ordering barriers 
Currently architectures can override __atomic_op_*() to define the barriers
used before/after a relaxed atomic when used to build acquire/release/fence
variants.

This has the unfortunate property of requiring the architecture to define the
full wrapper for the atomics, rather than just the barriers they care about,
and gets in the way of generating atomics which can be easily read.

Instead, this patch has architectures define an optional set of barriers:

* __atomic_acquire_fence()
* __atomic_release_fence()
* __atomic_pre_full_fence()
* __atomic_post_full_fence()

... which <linux/atomic.h> uses to build the wrappers.

It would be nice if we could undef these, along with the __atomic_op_*()
wrappers, but that would break the cmpxchg() wrappers, which are written
in preprocessor. Undefs would have been nice, but alas.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Andrea Parri <parri.andrea@gmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andy.shevchenko@gmail.com
Cc: arnd@arndb.de
Cc: aryabinin@virtuozzo.com
Cc: catalin.marinas@arm.com
Cc: dvyukov@google.com
Cc: glider@google.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: peter@hurleysoftware.com
Link: http://lkml.kernel.org/r/20180716113017.3909-7-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-07-25 11:53:59 +02:00

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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_POWERPC_ATOMIC_H_
#define _ASM_POWERPC_ATOMIC_H_
/*
* PowerPC atomic operations
*/
#ifdef __KERNEL__
#include <linux/types.h>
#include <asm/cmpxchg.h>
#include <asm/barrier.h>
#define ATOMIC_INIT(i) { (i) }
/*
* Since *_return_relaxed and {cmp}xchg_relaxed are implemented with
* a "bne-" instruction at the end, so an isync is enough as a acquire barrier
* on the platform without lwsync.
*/
#define __atomic_acquire_fence() \
__asm__ __volatile__(PPC_ACQUIRE_BARRIER "" : : : "memory")
#define __atomic_release_fence() \
__asm__ __volatile__(PPC_RELEASE_BARRIER "" : : : "memory")
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));
}
#define ATOMIC_OP(op, asm_op) \
static __inline__ void atomic_##op(int a, atomic_t *v) \
{ \
int t; \
\
__asm__ __volatile__( \
"1: lwarx %0,0,%3 # atomic_" #op "\n" \
#asm_op " %0,%2,%0\n" \
PPC405_ERR77(0,%3) \
" stwcx. %0,0,%3 \n" \
" bne- 1b\n" \
: "=&r" (t), "+m" (v->counter) \
: "r" (a), "r" (&v->counter) \
: "cc"); \
} \
#define ATOMIC_OP_RETURN_RELAXED(op, asm_op) \
static inline int atomic_##op##_return_relaxed(int a, atomic_t *v) \
{ \
int t; \
\
__asm__ __volatile__( \
"1: lwarx %0,0,%3 # atomic_" #op "_return_relaxed\n" \
#asm_op " %0,%2,%0\n" \
PPC405_ERR77(0, %3) \
" stwcx. %0,0,%3\n" \
" bne- 1b\n" \
: "=&r" (t), "+m" (v->counter) \
: "r" (a), "r" (&v->counter) \
: "cc"); \
\
return t; \
}
#define ATOMIC_FETCH_OP_RELAXED(op, asm_op) \
static inline int atomic_fetch_##op##_relaxed(int a, atomic_t *v) \
{ \
int res, t; \
\
__asm__ __volatile__( \
"1: lwarx %0,0,%4 # atomic_fetch_" #op "_relaxed\n" \
#asm_op " %1,%3,%0\n" \
PPC405_ERR77(0, %4) \
" stwcx. %1,0,%4\n" \
" bne- 1b\n" \
: "=&r" (res), "=&r" (t), "+m" (v->counter) \
: "r" (a), "r" (&v->counter) \
: "cc"); \
\
return res; \
}
#define ATOMIC_OPS(op, asm_op) \
ATOMIC_OP(op, asm_op) \
ATOMIC_OP_RETURN_RELAXED(op, asm_op) \
ATOMIC_FETCH_OP_RELAXED(op, asm_op)
ATOMIC_OPS(add, add)
ATOMIC_OPS(sub, subf)
#define atomic_add_return_relaxed atomic_add_return_relaxed
#define atomic_sub_return_relaxed atomic_sub_return_relaxed
#define atomic_fetch_add_relaxed atomic_fetch_add_relaxed
#define atomic_fetch_sub_relaxed atomic_fetch_sub_relaxed
#undef ATOMIC_OPS
#define ATOMIC_OPS(op, asm_op) \
ATOMIC_OP(op, asm_op) \
ATOMIC_FETCH_OP_RELAXED(op, asm_op)
ATOMIC_OPS(and, and)
ATOMIC_OPS(or, or)
ATOMIC_OPS(xor, xor)
#define atomic_fetch_and_relaxed atomic_fetch_and_relaxed
#define atomic_fetch_or_relaxed atomic_fetch_or_relaxed
#define atomic_fetch_xor_relaxed atomic_fetch_xor_relaxed
#undef ATOMIC_OPS
#undef ATOMIC_FETCH_OP_RELAXED
#undef ATOMIC_OP_RETURN_RELAXED
#undef ATOMIC_OP
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");
}
#define atomic_inc atomic_inc
static __inline__ int atomic_inc_return_relaxed(atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%2 # atomic_inc_return_relaxed\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");
return t;
}
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");
}
#define atomic_dec atomic_dec
static __inline__ int atomic_dec_return_relaxed(atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%2 # atomic_dec_return_relaxed\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");
return t;
}
#define atomic_inc_return_relaxed atomic_inc_return_relaxed
#define atomic_dec_return_relaxed atomic_dec_return_relaxed
#define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
#define atomic_cmpxchg_relaxed(v, o, n) \
cmpxchg_relaxed(&((v)->counter), (o), (n))
#define atomic_cmpxchg_acquire(v, o, n) \
cmpxchg_acquire(&((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_fetch_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_fetch_add_unless(atomic_t *v, int a, int u)
{
int t;
__asm__ __volatile__ (
PPC_ATOMIC_ENTRY_BARRIER
"1: lwarx %0,0,%1 # atomic_fetch_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;
}
#define atomic_fetch_add_unless atomic_fetch_add_unless
/**
* 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))
/*
* 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 atomic_dec_if_positive atomic_dec_if_positive
#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));
}
#define ATOMIC64_OP(op, asm_op) \
static __inline__ void atomic64_##op(long a, atomic64_t *v) \
{ \
long t; \
\
__asm__ __volatile__( \
"1: ldarx %0,0,%3 # atomic64_" #op "\n" \
#asm_op " %0,%2,%0\n" \
" stdcx. %0,0,%3 \n" \
" bne- 1b\n" \
: "=&r" (t), "+m" (v->counter) \
: "r" (a), "r" (&v->counter) \
: "cc"); \
}
#define ATOMIC64_OP_RETURN_RELAXED(op, asm_op) \
static inline long \
atomic64_##op##_return_relaxed(long a, atomic64_t *v) \
{ \
long t; \
\
__asm__ __volatile__( \
"1: ldarx %0,0,%3 # atomic64_" #op "_return_relaxed\n" \
#asm_op " %0,%2,%0\n" \
" stdcx. %0,0,%3\n" \
" bne- 1b\n" \
: "=&r" (t), "+m" (v->counter) \
: "r" (a), "r" (&v->counter) \
: "cc"); \
\
return t; \
}
#define ATOMIC64_FETCH_OP_RELAXED(op, asm_op) \
static inline long \
atomic64_fetch_##op##_relaxed(long a, atomic64_t *v) \
{ \
long res, t; \
\
__asm__ __volatile__( \
"1: ldarx %0,0,%4 # atomic64_fetch_" #op "_relaxed\n" \
#asm_op " %1,%3,%0\n" \
" stdcx. %1,0,%4\n" \
" bne- 1b\n" \
: "=&r" (res), "=&r" (t), "+m" (v->counter) \
: "r" (a), "r" (&v->counter) \
: "cc"); \
\
return res; \
}
#define ATOMIC64_OPS(op, asm_op) \
ATOMIC64_OP(op, asm_op) \
ATOMIC64_OP_RETURN_RELAXED(op, asm_op) \
ATOMIC64_FETCH_OP_RELAXED(op, asm_op)
ATOMIC64_OPS(add, add)
ATOMIC64_OPS(sub, subf)
#define atomic64_add_return_relaxed atomic64_add_return_relaxed
#define atomic64_sub_return_relaxed atomic64_sub_return_relaxed
#define atomic64_fetch_add_relaxed atomic64_fetch_add_relaxed
#define atomic64_fetch_sub_relaxed atomic64_fetch_sub_relaxed
#undef ATOMIC64_OPS
#define ATOMIC64_OPS(op, asm_op) \
ATOMIC64_OP(op, asm_op) \
ATOMIC64_FETCH_OP_RELAXED(op, asm_op)
ATOMIC64_OPS(and, and)
ATOMIC64_OPS(or, or)
ATOMIC64_OPS(xor, xor)
#define atomic64_fetch_and_relaxed atomic64_fetch_and_relaxed
#define atomic64_fetch_or_relaxed atomic64_fetch_or_relaxed
#define atomic64_fetch_xor_relaxed atomic64_fetch_xor_relaxed
#undef ATOPIC64_OPS
#undef ATOMIC64_FETCH_OP_RELAXED
#undef ATOMIC64_OP_RETURN_RELAXED
#undef ATOMIC64_OP
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");
}
#define atomic64_inc atomic64_inc
static __inline__ long atomic64_inc_return_relaxed(atomic64_t *v)
{
long t;
__asm__ __volatile__(
"1: ldarx %0,0,%2 # atomic64_inc_return_relaxed\n"
" addic %0,%0,1\n"
" stdcx. %0,0,%2\n"
" bne- 1b"
: "=&r" (t), "+m" (v->counter)
: "r" (&v->counter)
: "cc", "xer");
return t;
}
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");
}
#define atomic64_dec atomic64_dec
static __inline__ long atomic64_dec_return_relaxed(atomic64_t *v)
{
long t;
__asm__ __volatile__(
"1: ldarx %0,0,%2 # atomic64_dec_return_relaxed\n"
" addic %0,%0,-1\n"
" stdcx. %0,0,%2\n"
" bne- 1b"
: "=&r" (t), "+m" (v->counter)
: "r" (&v->counter)
: "cc", "xer");
return t;
}
#define atomic64_inc_return_relaxed atomic64_inc_return_relaxed
#define atomic64_dec_return_relaxed atomic64_dec_return_relaxed
/*
* 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_dec_if_positive atomic64_dec_if_positive
#define atomic64_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
#define atomic64_cmpxchg_relaxed(v, o, n) \
cmpxchg_relaxed(&((v)->counter), (o), (n))
#define atomic64_cmpxchg_acquire(v, o, n) \
cmpxchg_acquire(&((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_fetch_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__ long atomic64_fetch_add_unless(atomic64_t *v, long a, long u)
{
long t;
__asm__ __volatile__ (
PPC_ATOMIC_ENTRY_BARRIER
"1: ldarx %0,0,%1 # atomic64_fetch_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;
}
#define atomic64_fetch_add_unless atomic64_fetch_add_unless
/**
* 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__ int 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 != 0;
}
#define atomic64_inc_not_zero(v) atomic64_inc_not_zero((v))
#endif /* __powerpc64__ */
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_ATOMIC_H_ */
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