include/asm-h8300/system.h

   1 #ifndef _H8300_SYSTEM_H
   2 #define _H8300_SYSTEM_H
   3
   4 #include <linux/linkage.h>
   5
   6 /*
   7  * switch_to(n) should switch tasks to task ptr, first checking that
   8  * ptr isn't the current task, in which case it does nothing.  This
   9  * also clears the TS-flag if the task we switched to has used the
  10  * math co-processor latest.
  11  */
  12 /*
  13  * switch_to() saves the extra registers, that are not saved
  14  * automatically by SAVE_SWITCH_STACK in resume(), ie. d0-d5 and
  15  * a0-a1. Some of these are used by schedule() and its predecessors
  16  * and so we might get see unexpected behaviors when a task returns
  17  * with unexpected register values.
  18  *
  19  * syscall stores these registers itself and none of them are used
  20  * by syscall after the function in the syscall has been called.
  21  *
  22  * Beware that resume now expects *next to be in d1 and the offset of
  23  * tss to be in a1. This saves a few instructions as we no longer have
  24  * to push them onto the stack and read them back right after.
  25  *
  26  * 02/17/96 - Jes Sorensen (jds@kom.auc.dk)
  27  *
  28  * Changed 96/09/19 by Andreas Schwab
  29  * pass prev in a0, next in a1, offset of tss in d1, and whether
  30  * the mm structures are shared in d2 (to avoid atc flushing).
  31  *
  32  * H8/300 Porting 2002/09/04 Yoshinori Sato
  33  */
  34
  35 asmlinkage void resume(void);
  36 #define switch_to(prev,next,last) {                         \
  37   void *_last;                                              \
  38   __asm__ __volatile__(                                     \
  39                         "mov.l  %1, er0\n\t"                \
  40                         "mov.l  %2, er1\n\t"                \
  41                         "mov.l  %3, er2\n\t"                \
  42                         "jsr @_resume\n\t"                  \
  43                         "mov.l  er2,%0\n\t"                 \
  44                        : "=r" (_last)                       \
  45                        : "r" (&(prev->thread)),             \
  46                          "r" (&(next->thread)),             \
  47                          "g" (prev)                         \
  48                        : "cc", "er0", "er1", "er2", "er3"); \
  49   (last) = _last;                                           \
  50 }
  51
  52 #define __sti() asm volatile ("andc #0x7f,ccr")
  53 #define __cli() asm volatile ("orc  #0x80,ccr")
  54
  55 #define __save_flags(x) \
  56        asm volatile ("stc ccr,%w0":"=r" (x))
  57
  58 #define __restore_flags(x) \
  59        asm volatile ("ldc %w0,ccr": :"r" (x))
  60
  61 #define irqs_disabled()                 \
  62 ({                                      \
  63         unsigned char flags;            \
  64         __save_flags(flags);            \
  65         ((flags & 0x80) == 0x80);       \
  66 })
  67
  68 #define iret() __asm__ __volatile__ ("rte": : :"memory", "sp", "cc")
  69
  70 /* For spinlocks etc */
  71 #define local_irq_disable()     __cli()
  72 #define local_irq_enable()      __sti()
  73 #define local_irq_save(x)       ({ __save_flags(x); local_irq_disable(); })
  74 #define local_irq_restore(x)    __restore_flags(x)
  75 #define local_save_flags(x)     __save_flags(x)
  76
  77 /*
  78  * Force strict CPU ordering.
  79  * Not really required on H8...
  80  */
  81 #define nop()  asm volatile ("nop"::)
  82 #define mb()   asm volatile (""   : : :"memory")
  83 #define rmb()  asm volatile (""   : : :"memory")
  84 #define wmb()  asm volatile (""   : : :"memory")
  85 #define set_mb(var, value) do { xchg(&var, value); } while (0)
  86
  87 #ifdef CONFIG_SMP
  88 #define smp_mb()        mb()
  89 #define smp_rmb()       rmb()
  90 #define smp_wmb()       wmb()
  91 #define smp_read_barrier_depends()      read_barrier_depends()
  92 #else
  93 #define smp_mb()        barrier()
  94 #define smp_rmb()       barrier()
  95 #define smp_wmb()       barrier()
  96 #define smp_read_barrier_depends()      do { } while(0)
  97 #endif
  98
  99 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
 100
 101 struct __xchg_dummy { unsigned long a[100]; };
 102 #define __xg(x) ((volatile struct __xchg_dummy *)(x))
 103
 104 static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
 105 {
 106   unsigned long tmp, flags;
 107
 108   local_irq_save(flags);
 109
 110   switch (size) {
 111   case 1:
 112     __asm__ __volatile__
 113     ("mov.b %2,%0\n\t"
 114      "mov.b %1,%2"
 115     : "=&r" (tmp) : "r" (x), "m" (*__xg(ptr)) : "memory");
 116     break;
 117   case 2:
 118     __asm__ __volatile__
 119     ("mov.w %2,%0\n\t"
 120      "mov.w %1,%2"
 121     : "=&r" (tmp) : "r" (x), "m" (*__xg(ptr)) : "memory");
 122     break;
 123   case 4:
 124     __asm__ __volatile__
 125     ("mov.l %2,%0\n\t"
 126      "mov.l %1,%2"
 127     : "=&r" (tmp) : "r" (x), "m" (*__xg(ptr)) : "memory");
 128     break;
 129   default:
 130     tmp = 0;
 131   }
 132   local_irq_restore(flags);
 133   return tmp;
 134 }
 135
 136 #define HARD_RESET_NOW() ({             \
 137         local_irq_disable();            \
 138         asm("jmp @@0");                 \
 139 })
 140
 141 #define arch_align_stack(x) (x)
 142
 143 #endif /* _H8300_SYSTEM_H */