2
0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-23 04:34:11 +08:00
linux-next/include/asm-generic/cmpxchg-local.h
Ingo Molnar 5042afe7fe generic: Use raw local irq variant for generic cmpxchg
The interrupt disabled region is extremly tiny and therefor not
latency relevant. Avoid cluttering the traces with those pointless
entries.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-02-19 08:43:37 +01:00

67 lines
1.4 KiB
C

#ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
#define __ASM_GENERIC_CMPXCHG_LOCAL_H
#include <linux/types.h>
#include <linux/irqflags.h>
extern unsigned long wrong_size_cmpxchg(volatile void *ptr);
/*
* Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
* long parameter, supporting various types of architectures.
*/
static inline unsigned long __cmpxchg_local_generic(volatile void *ptr,
unsigned long old, unsigned long new, int size)
{
unsigned long flags, prev;
/*
* Sanity checking, compile-time.
*/
if (size == 8 && sizeof(unsigned long) != 8)
wrong_size_cmpxchg(ptr);
raw_local_irq_save(flags);
switch (size) {
case 1: prev = *(u8 *)ptr;
if (prev == old)
*(u8 *)ptr = (u8)new;
break;
case 2: prev = *(u16 *)ptr;
if (prev == old)
*(u16 *)ptr = (u16)new;
break;
case 4: prev = *(u32 *)ptr;
if (prev == old)
*(u32 *)ptr = (u32)new;
break;
case 8: prev = *(u64 *)ptr;
if (prev == old)
*(u64 *)ptr = (u64)new;
break;
default:
wrong_size_cmpxchg(ptr);
}
raw_local_irq_restore(flags);
return prev;
}
/*
* Generic version of __cmpxchg64_local. Takes an u64 parameter.
*/
static inline u64 __cmpxchg64_local_generic(volatile void *ptr,
u64 old, u64 new)
{
u64 prev;
unsigned long flags;
raw_local_irq_save(flags);
prev = *(u64 *)ptr;
if (prev == old)
*(u64 *)ptr = new;
raw_local_irq_restore(flags);
return prev;
}
#endif