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LoongArch: Add atomic/locking headers
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Add common headers (atomic, bitops, barrier and locking) for basic
LoongArch support.

Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Huacai Chen committed Jun 3, 2022
1 parent f2ac457 commit 5b0b14e
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358 changes: 358 additions & 0 deletions arch/loongarch/include/asm/atomic.h
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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Atomic operations.
*
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*/
#ifndef _ASM_ATOMIC_H
#define _ASM_ATOMIC_H

#include <linux/types.h>
#include <asm/barrier.h>
#include <asm/cmpxchg.h>
#include <asm/compiler.h>

#if __SIZEOF_LONG__ == 4
#define __LL "ll.w "
#define __SC "sc.w "
#define __AMADD "amadd.w "
#define __AMAND_DB "amand_db.w "
#define __AMOR_DB "amor_db.w "
#define __AMXOR_DB "amxor_db.w "
#elif __SIZEOF_LONG__ == 8
#define __LL "ll.d "
#define __SC "sc.d "
#define __AMADD "amadd.d "
#define __AMAND_DB "amand_db.d "
#define __AMOR_DB "amor_db.d "
#define __AMXOR_DB "amxor_db.d "
#endif

#define ATOMIC_INIT(i) { (i) }

/*
* arch_atomic_read - read atomic variable
* @v: pointer of type atomic_t
*
* Atomically reads the value of @v.
*/
#define arch_atomic_read(v) READ_ONCE((v)->counter)

/*
* arch_atomic_set - set atomic variable
* @v: pointer of type atomic_t
* @i: required value
*
* Atomically sets the value of @v to @i.
*/
#define arch_atomic_set(v, i) WRITE_ONCE((v)->counter, (i))

#define ATOMIC_OP(op, I, asm_op) \
static inline void arch_atomic_##op(int i, atomic_t *v) \
{ \
__asm__ __volatile__( \
"am"#asm_op"_db.w" " $zero, %1, %0 \n" \
: "+ZB" (v->counter) \
: "r" (I) \
: "memory"); \
}

#define ATOMIC_OP_RETURN(op, I, asm_op, c_op) \
static inline int arch_atomic_##op##_return_relaxed(int i, atomic_t *v) \
{ \
int result; \
\
__asm__ __volatile__( \
"am"#asm_op"_db.w" " %1, %2, %0 \n" \
: "+ZB" (v->counter), "=&r" (result) \
: "r" (I) \
: "memory"); \
\
return result c_op I; \
}

#define ATOMIC_FETCH_OP(op, I, asm_op) \
static inline int arch_atomic_fetch_##op##_relaxed(int i, atomic_t *v) \
{ \
int result; \
\
__asm__ __volatile__( \
"am"#asm_op"_db.w" " %1, %2, %0 \n" \
: "+ZB" (v->counter), "=&r" (result) \
: "r" (I) \
: "memory"); \
\
return result; \
}

#define ATOMIC_OPS(op, I, asm_op, c_op) \
ATOMIC_OP(op, I, asm_op) \
ATOMIC_OP_RETURN(op, I, asm_op, c_op) \
ATOMIC_FETCH_OP(op, I, asm_op)

ATOMIC_OPS(add, i, add, +)
ATOMIC_OPS(sub, -i, add, +)

#define arch_atomic_add_return_relaxed arch_atomic_add_return_relaxed
#define arch_atomic_sub_return_relaxed arch_atomic_sub_return_relaxed
#define arch_atomic_fetch_add_relaxed arch_atomic_fetch_add_relaxed
#define arch_atomic_fetch_sub_relaxed arch_atomic_fetch_sub_relaxed

#undef ATOMIC_OPS

#define ATOMIC_OPS(op, I, asm_op) \
ATOMIC_OP(op, I, asm_op) \
ATOMIC_FETCH_OP(op, I, asm_op)

ATOMIC_OPS(and, i, and)
ATOMIC_OPS(or, i, or)
ATOMIC_OPS(xor, i, xor)

#define arch_atomic_fetch_and_relaxed arch_atomic_fetch_and_relaxed
#define arch_atomic_fetch_or_relaxed arch_atomic_fetch_or_relaxed
#define arch_atomic_fetch_xor_relaxed arch_atomic_fetch_xor_relaxed

#undef ATOMIC_OPS
#undef ATOMIC_FETCH_OP
#undef ATOMIC_OP_RETURN
#undef ATOMIC_OP

static inline int arch_atomic_fetch_add_unless(atomic_t *v, int a, int u)
{
int prev, rc;

__asm__ __volatile__ (
"0: ll.w %[p], %[c]\n"
" beq %[p], %[u], 1f\n"
" add.w %[rc], %[p], %[a]\n"
" sc.w %[rc], %[c]\n"
" beqz %[rc], 0b\n"
" b 2f\n"
"1:\n"
__WEAK_LLSC_MB
"2:\n"
: [p]"=&r" (prev), [rc]"=&r" (rc),
[c]"=ZB" (v->counter)
: [a]"r" (a), [u]"r" (u)
: "memory");

return prev;
}
#define arch_atomic_fetch_add_unless arch_atomic_fetch_add_unless

/*
* arch_atomic_sub_if_positive - conditionally subtract integer from atomic variable
* @i: integer value to subtract
* @v: pointer of type atomic_t
*
* Atomically test @v and subtract @i if @v is greater or equal than @i.
* The function returns the old value of @v minus @i.
*/
static inline int arch_atomic_sub_if_positive(int i, atomic_t *v)
{
int result;
int temp;

if (__builtin_constant_p(i)) {
__asm__ __volatile__(
"1: ll.w %1, %2 # atomic_sub_if_positive\n"
" addi.w %0, %1, %3 \n"
" or %1, %0, $zero \n"
" blt %0, $zero, 2f \n"
" sc.w %1, %2 \n"
" beq $zero, %1, 1b \n"
"2: \n"
: "=&r" (result), "=&r" (temp),
"+" GCC_OFF_SMALL_ASM() (v->counter)
: "I" (-i));
} else {
__asm__ __volatile__(
"1: ll.w %1, %2 # atomic_sub_if_positive\n"
" sub.w %0, %1, %3 \n"
" or %1, %0, $zero \n"
" blt %0, $zero, 2f \n"
" sc.w %1, %2 \n"
" beq $zero, %1, 1b \n"
"2: \n"
: "=&r" (result), "=&r" (temp),
"+" GCC_OFF_SMALL_ASM() (v->counter)
: "r" (i));
}

return result;
}

#define arch_atomic_cmpxchg(v, o, n) (arch_cmpxchg(&((v)->counter), (o), (n)))
#define arch_atomic_xchg(v, new) (arch_xchg(&((v)->counter), (new)))

/*
* arch_atomic_dec_if_positive - decrement by 1 if old value positive
* @v: pointer of type atomic_t
*/
#define arch_atomic_dec_if_positive(v) arch_atomic_sub_if_positive(1, v)

#ifdef CONFIG_64BIT

#define ATOMIC64_INIT(i) { (i) }

/*
* arch_atomic64_read - read atomic variable
* @v: pointer of type atomic64_t
*
*/
#define arch_atomic64_read(v) READ_ONCE((v)->counter)

/*
* arch_atomic64_set - set atomic variable
* @v: pointer of type atomic64_t
* @i: required value
*/
#define arch_atomic64_set(v, i) WRITE_ONCE((v)->counter, (i))

#define ATOMIC64_OP(op, I, asm_op) \
static inline void arch_atomic64_##op(long i, atomic64_t *v) \
{ \
__asm__ __volatile__( \
"am"#asm_op"_db.d " " $zero, %1, %0 \n" \
: "+ZB" (v->counter) \
: "r" (I) \
: "memory"); \
}

#define ATOMIC64_OP_RETURN(op, I, asm_op, c_op) \
static inline long arch_atomic64_##op##_return_relaxed(long i, atomic64_t *v) \
{ \
long result; \
__asm__ __volatile__( \
"am"#asm_op"_db.d " " %1, %2, %0 \n" \
: "+ZB" (v->counter), "=&r" (result) \
: "r" (I) \
: "memory"); \
\
return result c_op I; \
}

#define ATOMIC64_FETCH_OP(op, I, asm_op) \
static inline long arch_atomic64_fetch_##op##_relaxed(long i, atomic64_t *v) \
{ \
long result; \
\
__asm__ __volatile__( \
"am"#asm_op"_db.d " " %1, %2, %0 \n" \
: "+ZB" (v->counter), "=&r" (result) \
: "r" (I) \
: "memory"); \
\
return result; \
}

#define ATOMIC64_OPS(op, I, asm_op, c_op) \
ATOMIC64_OP(op, I, asm_op) \
ATOMIC64_OP_RETURN(op, I, asm_op, c_op) \
ATOMIC64_FETCH_OP(op, I, asm_op)

ATOMIC64_OPS(add, i, add, +)
ATOMIC64_OPS(sub, -i, add, +)

#define arch_atomic64_add_return_relaxed arch_atomic64_add_return_relaxed
#define arch_atomic64_sub_return_relaxed arch_atomic64_sub_return_relaxed
#define arch_atomic64_fetch_add_relaxed arch_atomic64_fetch_add_relaxed
#define arch_atomic64_fetch_sub_relaxed arch_atomic64_fetch_sub_relaxed

#undef ATOMIC64_OPS

#define ATOMIC64_OPS(op, I, asm_op) \
ATOMIC64_OP(op, I, asm_op) \
ATOMIC64_FETCH_OP(op, I, asm_op)

ATOMIC64_OPS(and, i, and)
ATOMIC64_OPS(or, i, or)
ATOMIC64_OPS(xor, i, xor)

#define arch_atomic64_fetch_and_relaxed arch_atomic64_fetch_and_relaxed
#define arch_atomic64_fetch_or_relaxed arch_atomic64_fetch_or_relaxed
#define arch_atomic64_fetch_xor_relaxed arch_atomic64_fetch_xor_relaxed

#undef ATOMIC64_OPS
#undef ATOMIC64_FETCH_OP
#undef ATOMIC64_OP_RETURN
#undef ATOMIC64_OP

static inline long arch_atomic64_fetch_add_unless(atomic64_t *v, long a, long u)
{
long prev, rc;

__asm__ __volatile__ (
"0: ll.d %[p], %[c]\n"
" beq %[p], %[u], 1f\n"
" add.d %[rc], %[p], %[a]\n"
" sc.d %[rc], %[c]\n"
" beqz %[rc], 0b\n"
" b 2f\n"
"1:\n"
__WEAK_LLSC_MB
"2:\n"
: [p]"=&r" (prev), [rc]"=&r" (rc),
[c] "=ZB" (v->counter)
: [a]"r" (a), [u]"r" (u)
: "memory");

return prev;
}
#define arch_atomic64_fetch_add_unless arch_atomic64_fetch_add_unless

/*
* arch_atomic64_sub_if_positive - conditionally subtract integer from atomic variable
* @i: integer value to subtract
* @v: pointer of type atomic64_t
*
* Atomically test @v and subtract @i if @v is greater or equal than @i.
* The function returns the old value of @v minus @i.
*/
static inline long arch_atomic64_sub_if_positive(long i, atomic64_t *v)
{
long result;
long temp;

if (__builtin_constant_p(i)) {
__asm__ __volatile__(
"1: ll.d %1, %2 # atomic64_sub_if_positive \n"
" addi.d %0, %1, %3 \n"
" or %1, %0, $zero \n"
" blt %0, $zero, 2f \n"
" sc.d %1, %2 \n"
" beq %1, $zero, 1b \n"
"2: \n"
: "=&r" (result), "=&r" (temp),
"+" GCC_OFF_SMALL_ASM() (v->counter)
: "I" (-i));
} else {
__asm__ __volatile__(
"1: ll.d %1, %2 # atomic64_sub_if_positive \n"
" sub.d %0, %1, %3 \n"
" or %1, %0, $zero \n"
" blt %0, $zero, 2f \n"
" sc.d %1, %2 \n"
" beq %1, $zero, 1b \n"
"2: \n"
: "=&r" (result), "=&r" (temp),
"+" GCC_OFF_SMALL_ASM() (v->counter)
: "r" (i));
}

return result;
}

#define arch_atomic64_cmpxchg(v, o, n) \
((__typeof__((v)->counter))arch_cmpxchg(&((v)->counter), (o), (n)))
#define arch_atomic64_xchg(v, new) (arch_xchg(&((v)->counter), (new)))

/*
* arch_atomic64_dec_if_positive - decrement by 1 if old value positive
* @v: pointer of type atomic64_t
*/
#define arch_atomic64_dec_if_positive(v) arch_atomic64_sub_if_positive(1, v)

#endif /* CONFIG_64BIT */

#endif /* _ASM_ATOMIC_H */
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