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riscv: atomic: Add custom conditional atomic operation implementation

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Add conditional atomic operations' custom implementation (similar
to dec_if_positive), here is the list:
 - arch_atomic_inc_unless_negative
 - arch_atomic_dec_unless_positive
 - arch_atomic64_inc_unless_negative
 - arch_atomic64_dec_unless_positive

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20220505035526.2974382-4-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Guo Ren 2022-05-05 11:55:24 +08:00 committed by Palmer Dabbelt
parent 1d7f6932c5
commit 4420658a4a
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1 changed files with 82 additions and 0 deletions
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82
arch/riscv/include/asm/atomic.h
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@ -310,6 +310,46 @@ ATOMIC_OPS()
#undef ATOMIC_OPS
#undef ATOMIC_OP
static __always_inline bool arch_atomic_inc_unless_negative(atomic_t *v)
{
int prev, rc;
__asm__ __volatile__ (
"0: lr.w %[p], %[c]\n"
" bltz %[p], 1f\n"
" addi %[rc], %[p], 1\n"
" sc.w.rl %[rc], %[rc], %[c]\n"
" bnez %[rc], 0b\n"
" fence rw, rw\n"
"1:\n"
: [p]"=&r" (prev), [rc]"=&r" (rc), [c]"+A" (v->counter)
:
: "memory");
return !(prev < 0);
}
#define arch_atomic_inc_unless_negative arch_atomic_inc_unless_negative
static __always_inline bool arch_atomic_dec_unless_positive(atomic_t *v)
{
int prev, rc;
__asm__ __volatile__ (
"0: lr.w %[p], %[c]\n"
" bgtz %[p], 1f\n"
" addi %[rc], %[p], -1\n"
" sc.w.rl %[rc], %[rc], %[c]\n"
" bnez %[rc], 0b\n"
" fence rw, rw\n"
"1:\n"
: [p]"=&r" (prev), [rc]"=&r" (rc), [c]"+A" (v->counter)
:
: "memory");
return !(prev > 0);
}
#define arch_atomic_dec_unless_positive arch_atomic_dec_unless_positive
static __always_inline int arch_atomic_dec_if_positive(atomic_t *v)
{
int prev, rc;
@ -331,6 +371,48 @@ static __always_inline int arch_atomic_dec_if_positive(atomic_t *v)
#define arch_atomic_dec_if_positive arch_atomic_dec_if_positive
#ifndef CONFIG_GENERIC_ATOMIC64
static __always_inline bool arch_atomic64_inc_unless_negative(atomic64_t *v)
{
s64 prev;
long rc;
__asm__ __volatile__ (
"0: lr.d %[p], %[c]\n"
" bltz %[p], 1f\n"
" addi %[rc], %[p], 1\n"
" sc.d.rl %[rc], %[rc], %[c]\n"
" bnez %[rc], 0b\n"
" fence rw, rw\n"
"1:\n"
: [p]"=&r" (prev), [rc]"=&r" (rc), [c]"+A" (v->counter)
:
: "memory");
return !(prev < 0);
}
#define arch_atomic64_inc_unless_negative arch_atomic64_inc_unless_negative
static __always_inline bool arch_atomic64_dec_unless_positive(atomic64_t *v)
{
s64 prev;
long rc;
__asm__ __volatile__ (
"0: lr.d %[p], %[c]\n"
" bgtz %[p], 1f\n"
" addi %[rc], %[p], -1\n"
" sc.d.rl %[rc], %[rc], %[c]\n"
" bnez %[rc], 0b\n"
" fence rw, rw\n"
"1:\n"
: [p]"=&r" (prev), [rc]"=&r" (rc), [c]"+A" (v->counter)
:
: "memory");
return !(prev > 0);
}
#define arch_atomic64_dec_unless_positive arch_atomic64_dec_unless_positive
static __always_inline s64 arch_atomic64_dec_if_positive(atomic64_t *v)
{
s64 prev;