kernel-ark/include/asm-m68k/system.h
Steven Rostedt 52393ccc0a [PATCH] remove set_wmb - arch removal
set_wmb should not be used in the kernel because it just confuses the
code more and has no benefit.  Since it is not currently used in the
kernel this patch removes it so that new code does not include it.

All archs define set_wmb(var, value) to do { var = value; wmb(); }
while(0) except ia64 and sparc which use a mb() instead.  But this is
still moot since it is not used anyway.

Hasn't been tested on any archs but x86 and x86_64 (and only compiled
tested)

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-14 21:56:14 -07:00

200 lines
5.1 KiB
C

#ifndef _M68K_SYSTEM_H
#define _M68K_SYSTEM_H
#include <linux/linkage.h>
#include <linux/kernel.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)
/* interrupt control.. */
#if 0
#define local_irq_enable() asm volatile ("andiw %0,%%sr": : "i" (ALLOWINT) : "memory")
#else
#include <linux/hardirq.h>
#define local_irq_enable() ({ \
if (MACH_IS_Q40 || !hardirq_count()) \
asm volatile ("andiw %0,%%sr": : "i" (ALLOWINT) : "memory"); \
})
#endif
#define local_irq_disable() asm volatile ("oriw #0x0700,%%sr": : : "memory")
#define local_save_flags(x) asm volatile ("movew %%sr,%0":"=d" (x) : : "memory")
#define local_irq_restore(x) asm volatile ("movew %0,%%sr": :"d" (x) : "memory")
static inline int irqs_disabled(void)
{
unsigned long flags;
local_save_flags(flags);
return flags & ~ALLOWINT;
}
/* For spinlocks etc */
#define local_irq_save(x) ({ local_save_flags(x); local_irq_disable(); })
/*
* 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() do { } while(0)
#define set_mb(var, value) do { xchg(&var, value); } while (0)
#define smp_mb() barrier()
#define smp_rmb() barrier()
#define smp_wmb() barrier()
#define smp_read_barrier_depends() do { } while(0)
#define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
#define tas(ptr) (xchg((ptr),1))
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
/*
* 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))))
#endif
#define arch_align_stack(x) (x)
#endif /* __KERNEL__ */
#endif /* _M68K_SYSTEM_H */