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#ifndef _M68K_SYSTEM_H
#define _M68K_SYSTEM_H
#include <linux/linkage.h>
#include <linux/kernel.h>
#include <linux/bug.h>
#include <linux/irqflags.h>
#include <asm/segment.h>
#include <asm/entry.h>
#ifdef __KERNEL__
/*
* switch_to(n) should switch tasks to task ptr, first checking that
* ptr isn't the current task, in which case it does nothing. This
* also clears the TS-flag if the task we switched to has used the
* math co-processor latest.
*/
/*
* switch_to() saves the extra registers, that are not saved
* automatically by SAVE_SWITCH_STACK in resume(), ie. d0-d5 and
* a0-a1. Some of these are used by schedule() and its predecessors
* and so we might get see unexpected behaviors when a task returns
* with unexpected register values.
*
* syscall stores these registers itself and none of them are used
* by syscall after the function in the syscall has been called.
*
* Beware that resume now expects *next to be in d1 and the offset of
* tss to be in a1. This saves a few instructions as we no longer have
* to push them onto the stack and read them back right after.
*
* 02/17/96 - Jes Sorensen (jds@kom.auc.dk)
*
* Changed 96/09/19 by Andreas Schwab
* pass prev in a0, next in a1
*/
asmlinkage void resume(void);
#define switch_to(prev,next,last) do { \
register void *_prev __asm__ ("a0") = (prev); \
register void *_next __asm__ ("a1") = (next); \
register void *_last __asm__ ("d1"); \
__asm__ __volatile__("jbsr resume" \
: "=a" (_prev), "=a" (_next), "=d" (_last) \
: "0" (_prev), "1" (_next) \
: "d0", "d2", "d3", "d4", "d5"); \
(last) = _last; \
} while (0)
/*
* Force strict CPU ordering.
* Not really required on m68k...
*/
#define nop() do { asm volatile ("nop"); barrier(); } while (0)
#define mb() barrier()
#define rmb() barrier()
#define wmb() barrier()
#define read_barrier_depends() ((void)0)
#define set_mb(var, value) ({ (var) = (value); wmb(); })
#define smp_mb() barrier()
#define smp_rmb() barrier()
#define smp_wmb() barrier()
#define smp_read_barrier_depends() ((void)0)
#define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
struct __xchg_dummy { unsigned long a[100]; };
#define __xg(x) ((volatile struct __xchg_dummy *)(x))
#ifndef CONFIG_RMW_INSNS
static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
{
unsigned long flags, tmp;
local_irq_save(flags);
switch (size) {
case 1:
tmp = *(u8 *)ptr;
*(u8 *)ptr = x;
x = tmp;
break;
case 2:
tmp = *(u16 *)ptr;
*(u16 *)ptr = x;
x = tmp;
break;
case 4:
tmp = *(u32 *)ptr;
*(u32 *)ptr = x;
x = tmp;
break;
default:
BUG();
}
local_irq_restore(flags);
return x;
}
#else
static inline unsigned long __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(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(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(ptr)) : "memory");
break;
}
return x;
}
#endif
#include <asm-generic/cmpxchg-local.h>
#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
/*
* 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
#define __HAVE_ARCH_CMPXCHG 1
static inline unsigned long __cmpxchg(volatile void *p, unsigned long old,
unsigned long new, int size)
{
switch (size) {
case 1:
__asm__ __volatile__ ("casb %0,%2,%1"
: "=d" (old), "=m" (*(char *)p)
: "d" (new), "0" (old), "m" (*(char *)p));
break;
case 2:
__asm__ __volatile__ ("casw %0,%2,%1"
: "=d" (old), "=m" (*(short *)p)
: "d" (new), "0" (old), "m" (*(short *)p));
break;
case 4:
__asm__ __volatile__ ("casl %0,%2,%1"
: "=d" (old), "=m" (*(int *)p)
: "d" (new), "0" (old), "m" (*(int *)p));
break;
}
return old;
}
#define cmpxchg(ptr, o, n) \
((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o), \
(unsigned long)(n), sizeof(*(ptr))))
#define cmpxchg_local(ptr, o, n) \
((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o), \
(unsigned long)(n), sizeof(*(ptr))))
#else
/*
* cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
* them available.
*/
#define cmpxchg_local(ptr, o, n) \
((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
(unsigned long)(n), sizeof(*(ptr))))
#include <asm-generic/cmpxchg.h>
#endif
#define arch_align_stack(x) (x)
#endif /* __KERNEL__ */
#endif /* _M68K_SYSTEM_H */
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