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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

include/asm-generic/cmpxchg.h

+80 −7
Original line number Diff line number Diff line 
/*

 * 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 */

include/asm-generic/system.h

+0 −70
Original line number Diff line number Diff line
@@ -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 */