Commit b4816afa authored by David Howells's avatar David Howells
Browse files

Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h



Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h
to simplify disintegration of asm/system.h.
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
parent 885df91c
/*
* Generic UP xchg and cmpxchg using interrupt disablement. Does not
* support SMP.
*/
#ifndef __ASM_GENERIC_CMPXCHG_H
#define __ASM_GENERIC_CMPXCHG_H
/*
* Generic cmpxchg
*
* Uses the local cmpxchg. Does not support SMP.
*/
#ifdef CONFIG_SMP
#error "Cannot use generic cmpxchg on SMP"
#endif
#include <asm-generic/cmpxchg-local.h>
#include <linux/irqflags.h>
#ifndef xchg
/*
* This function doesn't exist, so you'll get a linker error if
* something tries to do an invalidly-sized xchg().
*/
extern void __xchg_called_with_bad_pointer(void);
static inline
unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
{
unsigned long ret, flags;
switch (size) {
case 1:
#ifdef __xchg_u8
return __xchg_u8(x, ptr);
#else
local_irq_save(flags);
ret = *(volatile u8 *)ptr;
*(volatile u8 *)ptr = x;
local_irq_restore(flags);
return ret;
#endif /* __xchg_u8 */
case 2:
#ifdef __xchg_u16
return __xchg_u16(x, ptr);
#else
local_irq_save(flags);
ret = *(volatile u16 *)ptr;
*(volatile u16 *)ptr = x;
local_irq_restore(flags);
return ret;
#endif /* __xchg_u16 */
case 4:
#ifdef __xchg_u32
return __xchg_u32(x, ptr);
#else
local_irq_save(flags);
ret = *(volatile u32 *)ptr;
*(volatile u32 *)ptr = x;
local_irq_restore(flags);
return ret;
#endif /* __xchg_u32 */
#ifdef CONFIG_64BIT
case 8:
#ifdef __xchg_u64
return __xchg_u64(x, ptr);
#else
local_irq_save(flags);
ret = *(volatile u64 *)ptr;
*(volatile u64 *)ptr = x;
local_irq_restore(flags);
return ret;
#endif /* __xchg_u64 */
#endif /* CONFIG_64BIT */
default:
__xchg_called_with_bad_pointer();
return x;
}
}
#define xchg(ptr, x) \
((__typeof__(*(ptr))) __xchg((unsigned long)(x), (ptr), sizeof(*(ptr))))
#endif /* xchg */
/*
* Atomic compare and exchange.
......@@ -18,7 +89,9 @@
* Do not define __HAVE_ARCH_CMPXCHG because we want to use it to check whether
* a cmpxchg primitive faster than repeated local irq save/restore exists.
*/
#include <asm-generic/cmpxchg-local.h>
#define cmpxchg(ptr, o, n) cmpxchg_local((ptr), (o), (n))
#define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n))
#endif
#endif /* __ASM_GENERIC_CMPXCHG_H */
......@@ -17,7 +17,6 @@
#ifndef __ASSEMBLY__
#include <linux/types.h>
#include <linux/irqflags.h>
#include <asm/barrier.h>
#include <asm/cmpxchg.h>
......@@ -34,75 +33,6 @@ extern struct task_struct *__switch_to(struct task_struct *,
#define arch_align_stack(x) (x)
/*
* we make sure local_irq_enable() doesn't cause priority inversion
*/
/* This function doesn't exist, so you'll get a linker error
* if something tries to do an invalid xchg(). */
extern void __xchg_called_with_bad_pointer(void);
static inline
unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
{
unsigned long ret, flags;
switch (size) {
case 1:
#ifdef __xchg_u8
return __xchg_u8(x, ptr);
#else
local_irq_save(flags);
ret = *(volatile u8 *)ptr;
*(volatile u8 *)ptr = x;
local_irq_restore(flags);
return ret;
#endif /* __xchg_u8 */
case 2:
#ifdef __xchg_u16
return __xchg_u16(x, ptr);
#else
local_irq_save(flags);
ret = *(volatile u16 *)ptr;
*(volatile u16 *)ptr = x;
local_irq_restore(flags);
return ret;
#endif /* __xchg_u16 */
case 4:
#ifdef __xchg_u32
return __xchg_u32(x, ptr);
#else
local_irq_save(flags);
ret = *(volatile u32 *)ptr;
*(volatile u32 *)ptr = x;
local_irq_restore(flags);
return ret;
#endif /* __xchg_u32 */
#ifdef CONFIG_64BIT
case 8:
#ifdef __xchg_u64
return __xchg_u64(x, ptr);
#else
local_irq_save(flags);
ret = *(volatile u64 *)ptr;
*(volatile u64 *)ptr = x;
local_irq_restore(flags);
return ret;
#endif /* __xchg_u64 */
#endif /* CONFIG_64BIT */
default:
__xchg_called_with_bad_pointer();
return x;
}
}
#define xchg(ptr, x) \
((__typeof__(*(ptr))) __xchg((unsigned long)(x), (ptr), sizeof(*(ptr))))
#endif /* !__ASSEMBLY__ */
#endif /* __ASM_GENERIC_SYSTEM_H */
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