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linux/arch/arm64/include/asm/atomic_ll_sc.h
Peter Zijlstra e490f9b1d3 locking/atomic, arch/arm64: Implement atomic{,64}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}() 
Implement FETCH-OP atomic primitives, these are very similar to the
existing OP-RETURN primitives we already have, except they return the
value of the atomic variable _before_ modification.

This is especially useful for irreversible operations -- such as
bitops (because it becomes impossible to reconstruct the state prior
to modification).

[wildea01: compile fixes for ll/sc]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-16 10:48:21 +02:00

332 lines
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/*
* Based on arch/arm/include/asm/atomic.h
*
* Copyright (C) 1996 Russell King.
* Copyright (C) 2002 Deep Blue Solutions Ltd.
* Copyright (C) 2012 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ASM_ATOMIC_LL_SC_H
#define __ASM_ATOMIC_LL_SC_H
#ifndef __ARM64_IN_ATOMIC_IMPL
#error "please don't include this file directly"
#endif
/*
* AArch64 UP and SMP safe atomic ops. We use load exclusive and
* store exclusive to ensure that these are atomic. We may loop
* to ensure that the update happens.
*
* NOTE: these functions do *not* follow the PCS and must explicitly
* save any clobbered registers other than x0 (regardless of return
* value). This is achieved through -fcall-saved-* compiler flags for
* this file, which unfortunately don't work on a per-function basis
* (the optimize attribute silently ignores these options).
*/
#define ATOMIC_OP(op, asm_op) \
__LL_SC_INLINE void \
__LL_SC_PREFIX(atomic_##op(int i, atomic_t *v)) \
{ \
unsigned long tmp; \
int result; \
\
asm volatile("// atomic_" #op "\n" \
" prfm pstl1strm, %2\n" \
"1: ldxr %w0, %2\n" \
" " #asm_op " %w0, %w0, %w3\n" \
" stxr %w1, %w0, %2\n" \
" cbnz %w1, 1b" \
: "=&r" (result), "=&r" (tmp), "+Q" (v->counter) \
: "Ir" (i)); \
} \
__LL_SC_EXPORT(atomic_##op);
#define ATOMIC_OP_RETURN(name, mb, acq, rel, cl, op, asm_op) \
__LL_SC_INLINE int \
__LL_SC_PREFIX(atomic_##op##_return##name(int i, atomic_t *v)) \
{ \
unsigned long tmp; \
int result; \
\
asm volatile("// atomic_" #op "_return" #name "\n" \
" prfm pstl1strm, %2\n" \
"1: ld" #acq "xr %w0, %2\n" \
" " #asm_op " %w0, %w0, %w3\n" \
" st" #rel "xr %w1, %w0, %2\n" \
" cbnz %w1, 1b\n" \
" " #mb \
: "=&r" (result), "=&r" (tmp), "+Q" (v->counter) \
: "Ir" (i) \
: cl); \
\
return result; \
} \
__LL_SC_EXPORT(atomic_##op##_return##name);
#define ATOMIC_FETCH_OP(name, mb, acq, rel, cl, op, asm_op) \
__LL_SC_INLINE int \
__LL_SC_PREFIX(atomic_fetch_##op##name(int i, atomic_t *v)) \
{ \
unsigned long tmp; \
int val, result; \
\
asm volatile("// atomic_fetch_" #op #name "\n" \
" prfm pstl1strm, %3\n" \
"1: ld" #acq "xr %w0, %3\n" \
" " #asm_op " %w1, %w0, %w4\n" \
" st" #rel "xr %w2, %w1, %3\n" \
" cbnz %w2, 1b\n" \
" " #mb \
: "=&r" (result), "=&r" (val), "=&r" (tmp), "+Q" (v->counter) \
: "Ir" (i) \
: cl); \
\
return result; \
} \
__LL_SC_EXPORT(atomic_fetch_##op##name);
#define ATOMIC_OPS(...) \
ATOMIC_OP(__VA_ARGS__) \
ATOMIC_OP_RETURN( , dmb ish, , l, "memory", __VA_ARGS__)\
ATOMIC_OP_RETURN(_relaxed, , , , , __VA_ARGS__)\
ATOMIC_OP_RETURN(_acquire, , a, , "memory", __VA_ARGS__)\
ATOMIC_OP_RETURN(_release, , , l, "memory", __VA_ARGS__)\
ATOMIC_FETCH_OP ( , dmb ish, , l, "memory", __VA_ARGS__)\
ATOMIC_FETCH_OP (_relaxed, , , , , __VA_ARGS__)\
ATOMIC_FETCH_OP (_acquire, , a, , "memory", __VA_ARGS__)\
ATOMIC_FETCH_OP (_release, , , l, "memory", __VA_ARGS__)
ATOMIC_OPS(add, add)
ATOMIC_OPS(sub, sub)
#undef ATOMIC_OPS
#define ATOMIC_OPS(...) \
ATOMIC_OP(__VA_ARGS__) \
ATOMIC_FETCH_OP ( , dmb ish, , l, "memory", __VA_ARGS__)\
ATOMIC_FETCH_OP (_relaxed, , , , , __VA_ARGS__)\
ATOMIC_FETCH_OP (_acquire, , a, , "memory", __VA_ARGS__)\
ATOMIC_FETCH_OP (_release, , , l, "memory", __VA_ARGS__)
ATOMIC_OPS(and, and)
ATOMIC_OPS(andnot, bic)
ATOMIC_OPS(or, orr)
ATOMIC_OPS(xor, eor)
#undef ATOMIC_OPS
#undef ATOMIC_FETCH_OP
#undef ATOMIC_OP_RETURN
#undef ATOMIC_OP
#define ATOMIC64_OP(op, asm_op) \
__LL_SC_INLINE void \
__LL_SC_PREFIX(atomic64_##op(long i, atomic64_t *v)) \
{ \
long result; \
unsigned long tmp; \
\
asm volatile("// atomic64_" #op "\n" \
" prfm pstl1strm, %2\n" \
"1: ldxr %0, %2\n" \
" " #asm_op " %0, %0, %3\n" \
" stxr %w1, %0, %2\n" \
" cbnz %w1, 1b" \
: "=&r" (result), "=&r" (tmp), "+Q" (v->counter) \
: "Ir" (i)); \
} \
__LL_SC_EXPORT(atomic64_##op);
#define ATOMIC64_OP_RETURN(name, mb, acq, rel, cl, op, asm_op) \
__LL_SC_INLINE long \
__LL_SC_PREFIX(atomic64_##op##_return##name(long i, atomic64_t *v)) \
{ \
long result; \
unsigned long tmp; \
\
asm volatile("// atomic64_" #op "_return" #name "\n" \
" prfm pstl1strm, %2\n" \
"1: ld" #acq "xr %0, %2\n" \
" " #asm_op " %0, %0, %3\n" \
" st" #rel "xr %w1, %0, %2\n" \
" cbnz %w1, 1b\n" \
" " #mb \
: "=&r" (result), "=&r" (tmp), "+Q" (v->counter) \
: "Ir" (i) \
: cl); \
\
return result; \
} \
__LL_SC_EXPORT(atomic64_##op##_return##name);
#define ATOMIC64_FETCH_OP(name, mb, acq, rel, cl, op, asm_op) \
__LL_SC_INLINE long \
__LL_SC_PREFIX(atomic64_fetch_##op##name(long i, atomic64_t *v)) \
{ \
long result, val; \
unsigned long tmp; \
\
asm volatile("// atomic64_fetch_" #op #name "\n" \
" prfm pstl1strm, %3\n" \
"1: ld" #acq "xr %0, %3\n" \
" " #asm_op " %1, %0, %4\n" \
" st" #rel "xr %w2, %1, %3\n" \
" cbnz %w2, 1b\n" \
" " #mb \
: "=&r" (result), "=&r" (val), "=&r" (tmp), "+Q" (v->counter) \
: "Ir" (i) \
: cl); \
\
return result; \
} \
__LL_SC_EXPORT(atomic64_fetch_##op##name);
#define ATOMIC64_OPS(...) \
ATOMIC64_OP(__VA_ARGS__) \
ATOMIC64_OP_RETURN(, dmb ish, , l, "memory", __VA_ARGS__) \
ATOMIC64_OP_RETURN(_relaxed,, , , , __VA_ARGS__) \
ATOMIC64_OP_RETURN(_acquire,, a, , "memory", __VA_ARGS__) \
ATOMIC64_OP_RETURN(_release,, , l, "memory", __VA_ARGS__) \
ATOMIC64_FETCH_OP (, dmb ish, , l, "memory", __VA_ARGS__) \
ATOMIC64_FETCH_OP (_relaxed,, , , , __VA_ARGS__) \
ATOMIC64_FETCH_OP (_acquire,, a, , "memory", __VA_ARGS__) \
ATOMIC64_FETCH_OP (_release,, , l, "memory", __VA_ARGS__)
ATOMIC64_OPS(add, add)
ATOMIC64_OPS(sub, sub)
#undef ATOMIC64_OPS
#define ATOMIC64_OPS(...) \
ATOMIC64_OP(__VA_ARGS__) \
ATOMIC64_FETCH_OP (, dmb ish, , l, "memory", __VA_ARGS__) \
ATOMIC64_FETCH_OP (_relaxed,, , , , __VA_ARGS__) \
ATOMIC64_FETCH_OP (_acquire,, a, , "memory", __VA_ARGS__) \
ATOMIC64_FETCH_OP (_release,, , l, "memory", __VA_ARGS__)
ATOMIC64_OPS(and, and)
ATOMIC64_OPS(andnot, bic)
ATOMIC64_OPS(or, orr)
ATOMIC64_OPS(xor, eor)
#undef ATOMIC64_OPS
#undef ATOMIC64_FETCH_OP
#undef ATOMIC64_OP_RETURN
#undef ATOMIC64_OP
__LL_SC_INLINE long
__LL_SC_PREFIX(atomic64_dec_if_positive(atomic64_t *v))
{
long result;
unsigned long tmp;
asm volatile("// atomic64_dec_if_positive\n"
" prfm pstl1strm, %2\n"
"1: ldxr %0, %2\n"
" subs %0, %0, #1\n"
" b.lt 2f\n"
" stlxr %w1, %0, %2\n"
" cbnz %w1, 1b\n"
" dmb ish\n"
"2:"
: "=&r" (result), "=&r" (tmp), "+Q" (v->counter)
:
: "cc", "memory");
return result;
}
__LL_SC_EXPORT(atomic64_dec_if_positive);
#define __CMPXCHG_CASE(w, sz, name, mb, acq, rel, cl) \
__LL_SC_INLINE unsigned long \
__LL_SC_PREFIX(__cmpxchg_case_##name(volatile void *ptr, \
unsigned long old, \
unsigned long new)) \
{ \
unsigned long tmp, oldval; \
\
asm volatile( \
" prfm pstl1strm, %[v]\n" \
"1: ld" #acq "xr" #sz "\t%" #w "[oldval], %[v]\n" \
" eor %" #w "[tmp], %" #w "[oldval], %" #w "[old]\n" \
" cbnz %" #w "[tmp], 2f\n" \
" st" #rel "xr" #sz "\t%w[tmp], %" #w "[new], %[v]\n" \
" cbnz %w[tmp], 1b\n" \
" " #mb "\n" \
" mov %" #w "[oldval], %" #w "[old]\n" \
"2:" \
: [tmp] "=&r" (tmp), [oldval] "=&r" (oldval), \
[v] "+Q" (*(unsigned long *)ptr) \
: [old] "Lr" (old), [new] "r" (new) \
: cl); \
\
return oldval; \
} \
__LL_SC_EXPORT(__cmpxchg_case_##name);
__CMPXCHG_CASE(w, b, 1, , , , )
__CMPXCHG_CASE(w, h, 2, , , , )
__CMPXCHG_CASE(w, , 4, , , , )
__CMPXCHG_CASE( , , 8, , , , )
__CMPXCHG_CASE(w, b, acq_1, , a, , "memory")
__CMPXCHG_CASE(w, h, acq_2, , a, , "memory")
__CMPXCHG_CASE(w, , acq_4, , a, , "memory")
__CMPXCHG_CASE( , , acq_8, , a, , "memory")
__CMPXCHG_CASE(w, b, rel_1, , , l, "memory")
__CMPXCHG_CASE(w, h, rel_2, , , l, "memory")
__CMPXCHG_CASE(w, , rel_4, , , l, "memory")
__CMPXCHG_CASE( , , rel_8, , , l, "memory")
__CMPXCHG_CASE(w, b, mb_1, dmb ish, , l, "memory")
__CMPXCHG_CASE(w, h, mb_2, dmb ish, , l, "memory")
__CMPXCHG_CASE(w, , mb_4, dmb ish, , l, "memory")
__CMPXCHG_CASE( , , mb_8, dmb ish, , l, "memory")
#undef __CMPXCHG_CASE
#define __CMPXCHG_DBL(name, mb, rel, cl) \
__LL_SC_INLINE long \
__LL_SC_PREFIX(__cmpxchg_double##name(unsigned long old1, \
unsigned long old2, \
unsigned long new1, \
unsigned long new2, \
volatile void *ptr)) \
{ \
unsigned long tmp, ret; \
\
asm volatile("// __cmpxchg_double" #name "\n" \
" prfm pstl1strm, %2\n" \
"1: ldxp %0, %1, %2\n" \
" eor %0, %0, %3\n" \
" eor %1, %1, %4\n" \
" orr %1, %0, %1\n" \
" cbnz %1, 2f\n" \
" st" #rel "xp %w0, %5, %6, %2\n" \
" cbnz %w0, 1b\n" \
" " #mb "\n" \
"2:" \
: "=&r" (tmp), "=&r" (ret), "+Q" (*(unsigned long *)ptr) \
: "r" (old1), "r" (old2), "r" (new1), "r" (new2) \
: cl); \
\
return ret; \
} \
__LL_SC_EXPORT(__cmpxchg_double##name);
__CMPXCHG_DBL( , , , )
__CMPXCHG_DBL(_mb, dmb ish, l, "memory")
#undef __CMPXCHG_DBL
#endif /* __ASM_ATOMIC_LL_SC_H */
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