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Diffstat (limited to 'include/asm-m68k/system.h')
| -rw-r--r-- | include/asm-m68k/system.h | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/include/asm-m68k/system.h b/include/asm-m68k/system.h new file mode 100644 index 00000000000..64d3481df74 --- /dev/null +++ b/include/asm-m68k/system.h @@ -0,0 +1,201 @@ +#ifndef _M68K_SYSTEM_H +#define _M68K_SYSTEM_H + +#include <linux/config.h> /* get configuration macros */ +#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 set_wmb(var, value) do { var = value; wmb(); } 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 */ |