arch/arc/include/asm/atomic-llsc.h

Source file repositories/reference/linux-study-clean/arch/arc/include/asm/atomic-llsc.h

File Facts

System
Linux kernel
Corpus path
arch/arc/include/asm/atomic-llsc.h
Extension
.h
Size
2778 bytes
Lines
98
Domain
Architecture Layer
Bucket
arch/arc
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef _ASM_ARC_ATOMIC_LLSC_H
#define _ASM_ARC_ATOMIC_LLSC_H

#define arch_atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))

#define ATOMIC_OP(op, asm_op)					\
static inline void arch_atomic_##op(int i, atomic_t *v)			\
{									\
	unsigned int val;						\
									\
	__asm__ __volatile__(						\
	"1:	llock   %[val], [%[ctr]]		\n"		\
	"	" #asm_op " %[val], %[val], %[i]	\n"		\
	"	scond   %[val], [%[ctr]]		\n"		\
	"	bnz     1b				\n"		\
	: [val]	"=&r"	(val) /* Early clobber to prevent reg reuse */	\
	: [ctr]	"r"	(&v->counter), /* Not "m": llock only supports reg direct addr mode */	\
	  [i]	"ir"	(i)						\
	: "cc", "memory");						\
}									\

#define ATOMIC_OP_RETURN(op, asm_op)				\
static inline int arch_atomic_##op##_return_relaxed(int i, atomic_t *v)	\
{									\
	unsigned int val;						\
									\
	__asm__ __volatile__(						\
	"1:	llock   %[val], [%[ctr]]		\n"		\
	"	" #asm_op " %[val], %[val], %[i]	\n"		\
	"	scond   %[val], [%[ctr]]		\n"		\
	"	bnz     1b				\n"		\
	: [val]	"=&r"	(val)						\
	: [ctr]	"r"	(&v->counter),					\
	  [i]	"ir"	(i)						\
	: "cc", "memory");						\
									\
	return val;							\
}

#define arch_atomic_add_return_relaxed		arch_atomic_add_return_relaxed
#define arch_atomic_sub_return_relaxed		arch_atomic_sub_return_relaxed

#define ATOMIC_FETCH_OP(op, asm_op)				\
static inline int arch_atomic_fetch_##op##_relaxed(int i, atomic_t *v)	\
{									\
	unsigned int val, orig;						\
									\
	__asm__ __volatile__(						\
	"1:	llock   %[orig], [%[ctr]]		\n"		\
	"	" #asm_op " %[val], %[orig], %[i]	\n"		\
	"	scond   %[val], [%[ctr]]		\n"		\
	"	bnz     1b				\n"		\
	: [val]	"=&r"	(val),						\
	  [orig] "=&r" (orig)						\
	: [ctr]	"r"	(&v->counter),					\
	  [i]	"ir"	(i)						\
	: "cc", "memory");						\
									\
	return orig;							\
}

#define arch_atomic_fetch_add_relaxed		arch_atomic_fetch_add_relaxed
#define arch_atomic_fetch_sub_relaxed		arch_atomic_fetch_sub_relaxed

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

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

ATOMIC_OPS(add, add)
ATOMIC_OPS(sub, sub)

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

ATOMIC_OPS(and, and)
ATOMIC_OPS(andnot, bic)
ATOMIC_OPS(or, or)
ATOMIC_OPS(xor, xor)

#define arch_atomic_andnot		arch_atomic_andnot

#undef ATOMIC_OPS

Annotation

Implementation Notes