/* SPDX-License-Identifier: GPL-2.0-only */
/*
* 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.
*/
#ifndef __ASM_ATOMIC_LL_SC_H
#define __ASM_ATOMIC_LL_SC_H
#include <linux/stringify.h>
#ifndef CONFIG_CC_HAS_K_CONSTRAINT
#define K
#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.
*/
#define ATOMIC_OP(op, asm_op, constraint) \
static __always_inline void \
__ll_sc_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\n" \
: "=&r" (result), "=&r" (tmp), "+Q" (v->counter) \
: __stringify(constraint) "r" (i)); \
}
#define ATOMIC_OP_RETURN(name, mb, acq, rel, cl, op, asm_op, constraint)\
static __always_inline int \
__ll_sc_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) \
: __stringify(constraint) "r" (i) \
: cl); \
\
return result; \
}
#define ATOMIC_FETCH_OP(name, mb, acq, rel, cl, op, asm_op, constraint) \
static __always_inline int \
__ll_sc_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) \
: __stringify(constraint) "r" (i) \
: cl); \
\
return result; \
}
#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, I)
ATOMIC_OPS(sub, sub, J)
#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, K)
ATOMIC_OPS(or, orr, K)
ATOMIC_OPS(xor, eor, K)
/*
* GAS converts the mysterious and undocumented BIC (immediate) alias to
* an AND (immediate) instruction with the immediate inverted. We don't
* have a constraint for this, so fall back to register.
*/
ATOMIC_OPS(andnot, bic, )
#undef ATOMIC_OPS
#undef ATOMIC_FETCH_OP
#undef ATOMIC_OP_RETURN
#undef ATOMIC_OP
#define ATOMIC64_OP(op, asm_op, constraint) \
static __always_inline void \
__ll_sc_atomic64_##op(s64 i, atomic64_t *v) \
{ \
s64 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) \
: __stringify(constraint) "r" (i)); \
}
#define ATOMIC64_OP_RETURN(name, mb, acq, rel, cl, op, asm_op, constraint)\
static __always_inline long \
__ll_sc_atomic64_##op##_return##name(s64 i, atomic64_t *v) \
{ \
s64 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) \
: __stringify(constraint) "r" (i) \
: cl); \
\
return result; \
}
#define ATOMIC64_FETCH_OP(name, mb, acq, rel, cl, op, asm_op, constraint)\
static __always_inline long \
__ll_sc_atomic64_fetch_##op##name(s64 i, atomic64_t *v) \
{ \
s64 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) \
: __stringify(constraint) "r" (i) \
: cl); \
\
return result; \
}
#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, I)
ATOMIC64_OPS(sub, sub, J)
#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, L)
ATOMIC64_OPS(or, orr, L)
ATOMIC64_OPS(xor, eor, L)
/*
* GAS converts the mysterious and undocumented BIC (immediate) alias to
* an AND (immediate) instruction with the immediate inverted. We don't
* have a constraint for this, so fall back to register.
*/
ATOMIC64_OPS(andnot, bic, )
#undef ATOMIC64_OPS
#undef ATOMIC64_FETCH_OP
#undef ATOMIC64_OP_RETURN
#undef ATOMIC64_OP
static __always_inline s64
__ll_sc_atomic64_dec_if_positive(atomic64_t *v)
{
s64 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;
}
#define __CMPXCHG_CASE(w, sfx, name, sz, mb, acq, rel, cl, constraint) \
static __always_inline u##sz \
__ll_sc__cmpxchg_case_##name##sz(volatile void *ptr, \
unsigned long old, \
u##sz new) \
{ \
unsigned long tmp; \
u##sz oldval; \
\
/* \
* Sub-word sizes require explicit casting so that the compare \
* part of the cmpxchg doesn't end up interpreting non-zero \
* upper bits of the register containing "old". \
*/ \
if (sz < 32) \
old = (u##sz)old; \
\
asm volatile( \
" prfm pstl1strm, %[v]\n" \
"1: ld" #acq "xr" #sfx "\t%" #w "[oldval], %[v]\n" \
" eor %" #w "[tmp], %" #w "[oldval], %" #w "[old]\n" \
" cbnz %" #w "[tmp], 2f\n" \
" st" #rel "xr" #sfx "\t%w[tmp], %" #w "[new], %[v]\n" \
" cbnz %w[tmp], 1b\n" \
" " #mb "\n" \
"2:" \
: [tmp] "=&r" (tmp), [oldval] "=&r" (oldval), \
[v] "+Q" (*(u##sz *)ptr) \
: [old] __stringify(constraint) "r" (old), [new] "r" (new) \
: cl); \
\
return oldval; \
}
/*
* Earlier versions of GCC (no later than 8.1.0) appear to incorrectly
* handle the 'K' constraint for the value 4294967295 - thus we use no
* constraint for 32 bit operations.
*/
__CMPXCHG_CASE(w, b, , 8, , , , , K)
__CMPXCHG_CASE(w, h, , 16, , , , , K)
__CMPXCHG_CASE(w, , , 32, , , , , K)
__CMPXCHG_CASE( , , , 64, , , , , L)
__CMPXCHG_CASE(w, b, acq_, 8, , a, , "memory", K)
__CMPXCHG_CASE(w, h, acq_, 16, , a, , "memory", K)
__CMPXCHG_CASE(w, , acq_, 32, , a, , "memory", K)
__CMPXCHG_CASE( , , acq_, 64, , a, , "memory", L)
__CMPXCHG_CASE(w, b, rel_, 8, , , l, "memory", K)
__CMPXCHG_CASE(w, h, rel_, 16, , , l, "memory", K)
__CMPXCHG_CASE(w, , rel_, 32, , , l, "memory", K)
__CMPXCHG_CASE( , , rel_, 64, , , l, "memory", L)
__CMPXCHG_CASE(w, b, mb_, 8, dmb ish, , l, "memory", K)
__CMPXCHG_CASE(w, h, mb_, 16, dmb ish, , l, "memory", K)
__CMPXCHG_CASE(w, , mb_, 32, dmb ish, , l, "memory", K)
__CMPXCHG_CASE( , , mb_, 64, dmb ish, , l, "memory", L)
#undef __CMPXCHG_CASE
union __u128_halves {
u128 full;
struct {
u64 low, high;
};
};
#define __CMPXCHG128(name, mb, rel, cl...) \
static __always_inline u128 \
__ll_sc__cmpxchg128##name(volatile u128 *ptr, u128 old, u128 new) \
{ \
union __u128_halves r, o = { .full = (old) }, \
n = { .full = (new) }; \
unsigned int tmp; \
\
asm volatile("// __cmpxchg128" #name "\n" \
" prfm pstl1strm, %[v]\n" \
"1: ldxp %[rl], %[rh], %[v]\n" \
" cmp %[rl], %[ol]\n" \
" ccmp %[rh], %[oh], 0, eq\n" \
" b.ne 2f\n" \
" st" #rel "xp %w[tmp], %[nl], %[nh], %[v]\n" \
" cbnz %w[tmp], 1b\n" \
" " #mb "\n" \
"2:" \
: [v] "+Q" (*(u128 *)ptr), \
[rl] "=&r" (r.low), [rh] "=&r" (r.high), \
[tmp] "=&r" (tmp) \
: [ol] "r" (o.low), [oh] "r" (o.high), \
[nl] "r" (n.low), [nh] "r" (n.high) \
: "cc", ##cl); \
\
return r.full; \
}
__CMPXCHG128( , , )
__CMPXCHG128(_mb, dmb ish, l, "memory")
#undef __CMPXCHG128
#undef K
#endif /* __ASM_ATOMIC_LL_SC_H */