mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-18 18:23:53 +08:00
3226aad81a
This completes the xchg implementation for sh architecture. Note: The llsc variant is tricky since this only supports 4 byte atomics, the existing implementation of 1 byte xchg is wrong: we need to do a 4 byte cmpxchg and retry if any bytes changed meanwhile. Write this in C for clarity. Suggested-by: Rich Felker <dalias@libc.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
72 lines
1.7 KiB
C
72 lines
1.7 KiB
C
#ifndef __ASM_SH_CMPXCHG_H
|
|
#define __ASM_SH_CMPXCHG_H
|
|
|
|
/*
|
|
* Atomic operations that C can't guarantee us. Useful for
|
|
* resource counting etc..
|
|
*/
|
|
|
|
#include <linux/compiler.h>
|
|
#include <linux/types.h>
|
|
|
|
#if defined(CONFIG_GUSA_RB)
|
|
#include <asm/cmpxchg-grb.h>
|
|
#elif defined(CONFIG_CPU_SH4A)
|
|
#include <asm/cmpxchg-llsc.h>
|
|
#else
|
|
#include <asm/cmpxchg-irq.h>
|
|
#endif
|
|
|
|
extern void __xchg_called_with_bad_pointer(void);
|
|
|
|
#define __xchg(ptr, x, size) \
|
|
({ \
|
|
unsigned long __xchg__res; \
|
|
volatile void *__xchg_ptr = (ptr); \
|
|
switch (size) { \
|
|
case 4: \
|
|
__xchg__res = xchg_u32(__xchg_ptr, x); \
|
|
break; \
|
|
case 2: \
|
|
__xchg__res = xchg_u16(__xchg_ptr, x); \
|
|
break; \
|
|
case 1: \
|
|
__xchg__res = xchg_u8(__xchg_ptr, x); \
|
|
break; \
|
|
default: \
|
|
__xchg_called_with_bad_pointer(); \
|
|
__xchg__res = x; \
|
|
break; \
|
|
} \
|
|
\
|
|
__xchg__res; \
|
|
})
|
|
|
|
#define xchg(ptr,x) \
|
|
((__typeof__(*(ptr)))__xchg((ptr),(unsigned long)(x), sizeof(*(ptr))))
|
|
|
|
/* This function doesn't exist, so you'll get a linker error
|
|
* if something tries to do an invalid cmpxchg(). */
|
|
extern void __cmpxchg_called_with_bad_pointer(void);
|
|
|
|
static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old,
|
|
unsigned long new, int size)
|
|
{
|
|
switch (size) {
|
|
case 4:
|
|
return __cmpxchg_u32(ptr, old, new);
|
|
}
|
|
__cmpxchg_called_with_bad_pointer();
|
|
return old;
|
|
}
|
|
|
|
#define cmpxchg(ptr,o,n) \
|
|
({ \
|
|
__typeof__(*(ptr)) _o_ = (o); \
|
|
__typeof__(*(ptr)) _n_ = (n); \
|
|
(__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
|
|
(unsigned long)_n_, sizeof(*(ptr))); \
|
|
})
|
|
|
|
#endif /* __ASM_SH_CMPXCHG_H */
|