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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* ARCv2 supports 64-bit exclusive load (LLOCKD) / store (SCONDD)
* - The address HAS to be 64-bit aligned
*/
#ifndef _ASM_ARC_ATOMIC64_ARCV2_H
#define _ASM_ARC_ATOMIC64_ARCV2_H
typedef struct {
s64 __aligned(8) counter;
} atomic64_t;
#define ATOMIC64_INIT(a) { (a) }
static inline s64 arch_atomic64_read(const atomic64_t *v)
{
s64 val;
__asm__ __volatile__(
" ldd %0, [%1] \n"
: "=r"(val)
: "r"(&v->counter));
return val;
}
static inline void arch_atomic64_set(atomic64_t *v, s64 a)
{
/*
* This could have been a simple assignment in "C" but would need
* explicit volatile. Otherwise gcc optimizers could elide the store
* which borked atomic64 self-test
* In the inline asm version, memory clobber needed for exact same
* reason, to tell gcc about the store.
*
* This however is not needed for sibling atomic64_add() etc since both
* load/store are explicitly done in inline asm. As long as API is used
* for each access, gcc has no way to optimize away any load/store
*/
__asm__ __volatile__(
" std %0, [%1] \n"
:
: "r"(a), "r"(&v->counter)
: "memory");
}
#define ATOMIC64_OP(op, op1, op2) \
static inline void arch_atomic64_##op(s64 a, atomic64_t *v) \
{ \
s64 val; \
\
__asm__ __volatile__( \
"1: \n" \
" llockd %0, [%1] \n" \
" " #op1 " %L0, %L0, %L2 \n" \
" " #op2 " %H0, %H0, %H2 \n" \
" scondd %0, [%1] \n" \
" bnz 1b \n" \
: "=&r"(val) \
: "r"(&v->counter), "ir"(a) \
: "cc", "memory"); \
} \
#define ATOMIC64_OP_RETURN(op, op1, op2) \
static inline s64 arch_atomic64_##op##_return_relaxed(s64 a, atomic64_t *v) \
{ \
s64 val; \
\
__asm__ __volatile__( \
"1: \n" \
" llockd %0, [%1] \n" \
" " #op1 " %L0, %L0, %L2 \n" \
" " #op2 " %H0, %H0, %H2 \n" \
" scondd %0, [%1] \n" \
" bnz 1b \n" \
: [val] "=&r"(val) \
: "r"(&v->counter), "ir"(a) \
: "cc", "memory"); \
\
return val; \
}
#define arch_atomic64_add_return_relaxed arch_atomic64_add_return_relaxed
#define arch_atomic64_sub_return_relaxed arch_atomic64_sub_return_relaxed
#define ATOMIC64_FETCH_OP(op, op1, op2) \
static inline s64 arch_atomic64_fetch_##op##_relaxed(s64 a, atomic64_t *v) \
{ \
s64 val, orig; \
\
__asm__ __volatile__( \
"1: \n" \
" llockd %0, [%2] \n" \
" " #op1 " %L1, %L0, %L3 \n" \
" " #op2 " %H1, %H0, %H3 \n" \
" scondd %1, [%2] \n" \
" bnz 1b \n" \
: "=&r"(orig), "=&r"(val) \
: "r"(&v->counter), "ir"(a) \
: "cc", "memory"); \
\
return orig; \
}
#define arch_atomic64_fetch_add_relaxed arch_atomic64_fetch_add_relaxed
#define arch_atomic64_fetch_sub_relaxed arch_atomic64_fetch_sub_relaxed
#define arch_atomic64_fetch_and_relaxed arch_atomic64_fetch_and_relaxed
#define arch_atomic64_fetch_andnot_relaxed arch_atomic64_fetch_andnot_relaxed
#define arch_atomic64_fetch_or_relaxed arch_atomic64_fetch_or_relaxed
#define arch_atomic64_fetch_xor_relaxed arch_atomic64_fetch_xor_relaxed
#define ATOMIC64_OPS(op, op1, op2) \
ATOMIC64_OP(op, op1, op2) \
ATOMIC64_OP_RETURN(op, op1, op2) \
ATOMIC64_FETCH_OP(op, op1, op2)
ATOMIC64_OPS(add, add.f, adc)
ATOMIC64_OPS(sub, sub.f, sbc)
#undef ATOMIC64_OPS
#define ATOMIC64_OPS(op, op1, op2) \
ATOMIC64_OP(op, op1, op2) \
ATOMIC64_FETCH_OP(op, op1, op2)
ATOMIC64_OPS(and, and, and)
ATOMIC64_OPS(andnot, bic, bic)
ATOMIC64_OPS(or, or, or)
ATOMIC64_OPS(xor, xor, xor)
#define arch_atomic64_andnot arch_atomic64_andnot
#undef ATOMIC64_OPS
#undef ATOMIC64_FETCH_OP
#undef ATOMIC64_OP_RETURN
#undef ATOMIC64_OP
static inline s64
arch_atomic64_cmpxchg(atomic64_t *ptr, s64 expected, s64 new)
{
s64 prev;
smp_mb();
__asm__ __volatile__(
"1: llockd %0, [%1] \n"
" brne %L0, %L2, 2f \n"
" brne %H0, %H2, 2f \n"
" scondd %3, [%1] \n"
" bnz 1b \n"
"2: \n"
: "=&r"(prev)
: "r"(ptr), "ir"(expected), "r"(new)
: "cc"); /* memory clobber comes from smp_mb() */
smp_mb();
return prev;
}
static inline s64 arch_atomic64_xchg(atomic64_t *ptr, s64 new)
{
s64 prev;
smp_mb();
__asm__ __volatile__(
"1: llockd %0, [%1] \n"
" scondd %2, [%1] \n"
" bnz 1b \n"
"2: \n"
: "=&r"(prev)
: "r"(ptr), "r"(new)
: "cc"); /* memory clobber comes from smp_mb() */
smp_mb();
return prev;
}
/**
* arch_atomic64_dec_if_positive - decrement by 1 if old value positive
* @v: pointer of type atomic64_t
*
* The function returns the old value of *v minus 1, even if
* the atomic variable, v, was not decremented.
*/
static inline s64 arch_atomic64_dec_if_positive(atomic64_t *v)
{
s64 val;
smp_mb();
__asm__ __volatile__(
"1: llockd %0, [%1] \n"
" sub.f %L0, %L0, 1 # w0 - 1, set C on borrow\n"
" sub.c %H0, %H0, 1 # if C set, w1 - 1\n"
" brlt %H0, 0, 2f \n"
" scondd %0, [%1] \n"
" bnz 1b \n"
"2: \n"
: "=&r"(val)
: "r"(&v->counter)
: "cc"); /* memory clobber comes from smp_mb() */
smp_mb();
return val;
}
#define arch_atomic64_dec_if_positive arch_atomic64_dec_if_positive
/**
* arch_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, if it was not @u.
* Returns the old value of @v
*/
static inline s64 arch_atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
{
s64 old, temp;
smp_mb();
__asm__ __volatile__(
"1: llockd %0, [%2] \n"
" brne %L0, %L4, 2f # continue to add since v != u \n"
" breq.d %H0, %H4, 3f # return since v == u \n"
"2: \n"
" add.f %L1, %L0, %L3 \n"
" adc %H1, %H0, %H3 \n"
" scondd %1, [%2] \n"
" bnz 1b \n"
"3: \n"
: "=&r"(old), "=&r" (temp)
: "r"(&v->counter), "r"(a), "r"(u)
: "cc"); /* memory clobber comes from smp_mb() */
smp_mb();
return old;
}
#define arch_atomic64_fetch_add_unless arch_atomic64_fetch_add_unless
#endif
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