arch/m68k/include/asm/cmpxchg.h

Source file repositories/reference/linux-study-clean/arch/m68k/include/asm/cmpxchg.h

File Facts

System
Linux kernel
Corpus path
arch/m68k/include/asm/cmpxchg.h
Extension
.h
Size
3103 bytes
Lines
131
Domain
Architecture Layer
Bucket
arch/m68k
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 __ARCH_M68K_CMPXCHG__
#define __ARCH_M68K_CMPXCHG__

#include <linux/irqflags.h>
#include <linux/minmax.h>

#define __xg(type, x) ((volatile type *)(x))

extern unsigned long __invalid_xchg_size(unsigned long, volatile void *, int);

#ifndef CONFIG_RMW_INSNS
static inline unsigned long __arch_xchg(unsigned long x, volatile void * ptr, int size)
{
	unsigned long flags;

	local_irq_save(flags);

	switch (size) {
	case 1:
		swap(*(u8 *)ptr, x);
		break;
	case 2:
		swap(*(u16 *)ptr, x);
		break;
	case 4:
		swap(*(u32 *)ptr, x);
		break;
	default:
		x = __invalid_xchg_size(x, ptr, size);
		break;
	}

	local_irq_restore(flags);
	return x;
}
#else
static inline unsigned long __arch_xchg(unsigned long x, volatile void * ptr, int size)
{
	switch (size) {
	case 1:
		__asm__ __volatile__
			("moveb %2,%0\n\t"
			 "1:\n\t"
			 "casb %0,%1,%2\n\t"
			 "jne 1b"
			 : "=&d" (x) : "d" (x), "m" (*__xg(u8, ptr)) : "memory");
		break;
	case 2:
		__asm__ __volatile__
			("movew %2,%0\n\t"
			 "1:\n\t"
			 "casw %0,%1,%2\n\t"
			 "jne 1b"
			 : "=&d" (x) : "d" (x), "m" (*__xg(u16, ptr)) : "memory");
		break;
	case 4:
		__asm__ __volatile__
			("movel %2,%0\n\t"
			 "1:\n\t"
			 "casl %0,%1,%2\n\t"
			 "jne 1b"
			 : "=&d" (x) : "d" (x), "m" (*__xg(u32, ptr)) : "memory");
		break;
	default:
		x = __invalid_xchg_size(x, ptr, size);
		break;
	}
	return x;
}
#endif

#define arch_xchg(ptr,x) ({(__typeof__(*(ptr)))__arch_xchg((unsigned long)(x),(ptr),sizeof(*(ptr)));})

#include <asm-generic/cmpxchg-local.h>

#define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))

extern unsigned long __invalid_cmpxchg_size(volatile void *,
					    unsigned long, unsigned long, int);

/*
 * Atomic compare and exchange.  Compare OLD with MEM, if identical,
 * store NEW in MEM.  Return the initial value in MEM.  Success is
 * indicated by comparing RETURN with OLD.
 */
#ifdef CONFIG_RMW_INSNS

static inline unsigned long __cmpxchg(volatile void *p, unsigned long old,
				      unsigned long new, int size)
{

Annotation

Implementation Notes