arch/m68k/include/asm/system_no.h

   1 #ifndef _M68KNOMMU_SYSTEM_H
   2 #define _M68KNOMMU_SYSTEM_H
   3
   4 #include <linux/linkage.h>
   5 #include <asm/segment.h>
   6 #include <asm/entry.h>
   7
   8 /*
   9  * switch_to(n) should switch tasks to task ptr, first checking that
  10  * ptr isn't the current task, in which case it does nothing.  This
  11  * also clears the TS-flag if the task we switched to has used the
  12  * math co-processor latest.
  13  */
  14 /*
  15  * switch_to() saves the extra registers, that are not saved
  16  * automatically by SAVE_SWITCH_STACK in resume(), ie. d0-d5 and
  17  * a0-a1. Some of these are used by schedule() and its predecessors
  18  * and so we might get see unexpected behaviors when a task returns
  19  * with unexpected register values.
  20  *
  21  * syscall stores these registers itself and none of them are used
  22  * by syscall after the function in the syscall has been called.
  23  *
  24  * Beware that resume now expects *next to be in d1 and the offset of
  25  * tss to be in a1. This saves a few instructions as we no longer have
  26  * to push them onto the stack and read them back right after.
  27  *
  28  * 02/17/96 - Jes Sorensen (jds@kom.auc.dk)
  29  *
  30  * Changed 96/09/19 by Andreas Schwab
  31  * pass prev in a0, next in a1, offset of tss in d1, and whether
  32  * the mm structures are shared in d2 (to avoid atc flushing).
  33  */
  34 asmlinkage void resume(void);
  35 #define switch_to(prev,next,last)                               \
  36 {                                                               \
  37   void *_last;                                                  \
  38   __asm__ __volatile__(                                         \
  39         "movel  %1, %%a0\n\t"                                   \
  40         "movel  %2, %%a1\n\t"                                   \
  41         "jbsr resume\n\t"                                       \
  42         "movel  %%d1, %0\n\t"                                   \
  43        : "=d" (_last)                                           \
  44        : "d" (prev), "d" (next)                                 \
  45        : "cc", "d0", "d1", "d2", "d3", "d4", "d5", "a0", "a1"); \
  46   (last) = _last;                                               \
  47 }
  48
  49 #ifdef CONFIG_COLDFIRE
  50 #define local_irq_enable() __asm__ __volatile__ (               \
  51         "move %/sr,%%d0\n\t"                                    \
  52         "andi.l #0xf8ff,%%d0\n\t"                               \
  53         "move %%d0,%/sr\n"                                      \
  54         : /* no outputs */                                      \
  55         :                                                       \
  56         : "cc", "%d0", "memory")
  57 #define local_irq_disable() __asm__ __volatile__ (              \
  58         "move %/sr,%%d0\n\t"                                    \
  59         "ori.l #0x0700,%%d0\n\t"                                \
  60         "move %%d0,%/sr\n"                                      \
  61         : /* no outputs */                                      \
  62         :                                                       \
  63         : "cc", "%d0", "memory")
  64 /* For spinlocks etc */
  65 #define local_irq_save(x) __asm__ __volatile__ (                \
  66         "movew %%sr,%0\n\t"                                     \
  67         "movew #0x0700,%%d0\n\t"                                \
  68         "or.l  %0,%%d0\n\t"                                     \
  69         "movew %%d0,%/sr"                                       \
  70         : "=d" (x)                                              \
  71         :                                                       \
  72         : "cc", "%d0", "memory")
  73 #else
  74
  75 /* portable version */ /* FIXME - see entry.h*/
  76 #define ALLOWINT 0xf8ff
  77
  78 #define local_irq_enable() asm volatile ("andiw %0,%%sr": : "i" (ALLOWINT) : "memory")
  79 #define local_irq_disable() asm volatile ("oriw  #0x0700,%%sr": : : "memory")
  80 #endif
  81
  82 #define local_save_flags(x) asm volatile ("movew %%sr,%0":"=d" (x) : : "memory")
  83 #define local_irq_restore(x) asm volatile ("movew %0,%%sr": :"d" (x) : "memory")
  84
  85 /* For spinlocks etc */
  86 #ifndef local_irq_save
  87 #define local_irq_save(x) do { local_save_flags(x); local_irq_disable(); } while (0)
  88 #endif
  89
  90 #define irqs_disabled()                 \
  91 ({                                      \
  92         unsigned long flags;            \
  93         local_save_flags(flags);        \
  94         ((flags & 0x0700) == 0x0700);   \
  95 })
  96
  97 #define iret() __asm__ __volatile__ ("rte": : :"memory", "sp", "cc")
  98
  99 /*
 100  * Force strict CPU ordering.
 101  * Not really required on m68k...
 102  */
 103 #define nop()  asm volatile ("nop"::)
 104 #define mb()   asm volatile (""   : : :"memory")
 105 #define rmb()  asm volatile (""   : : :"memory")
 106 #define wmb()  asm volatile (""   : : :"memory")
 107 #define set_mb(var, value)      ({ (var) = (value); wmb(); })
 108
 109 #ifdef CONFIG_SMP
 110 #define smp_mb()        mb()
 111 #define smp_rmb()       rmb()
 112 #define smp_wmb()       wmb()
 113 #define smp_read_barrier_depends()      read_barrier_depends()
 114 #else
 115 #define smp_mb()        barrier()
 116 #define smp_rmb()       barrier()
 117 #define smp_wmb()       barrier()
 118 #define smp_read_barrier_depends()      do { } while(0)
 119 #endif
 120
 121 #define read_barrier_depends()  ((void)0)
 122
 123 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
 124
 125 struct __xchg_dummy { unsigned long a[100]; };
 126 #define __xg(x) ((volatile struct __xchg_dummy *)(x))
 127
 128 #ifndef CONFIG_RMW_INSNS
 129 static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
 130 {
 131   unsigned long tmp, flags;
 132
 133   local_irq_save(flags);
 134
 135   switch (size) {
 136   case 1:
 137     __asm__ __volatile__
 138     ("moveb %2,%0\n\t"
 139      "moveb %1,%2"
 140     : "=&d" (tmp) : "d" (x), "m" (*__xg(ptr)) : "memory");
 141     break;
 142   case 2:
 143     __asm__ __volatile__
 144     ("movew %2,%0\n\t"
 145      "movew %1,%2"
 146     : "=&d" (tmp) : "d" (x), "m" (*__xg(ptr)) : "memory");
 147     break;
 148   case 4:
 149     __asm__ __volatile__
 150     ("movel %2,%0\n\t"
 151      "movel %1,%2"
 152     : "=&d" (tmp) : "d" (x), "m" (*__xg(ptr)) : "memory");
 153     break;
 154   }
 155   local_irq_restore(flags);
 156   return tmp;
 157 }
 158 #else
 159 static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
 160 {
 161         switch (size) {
 162             case 1:
 163                 __asm__ __volatile__
 164                         ("moveb %2,%0\n\t"
 165                          "1:\n\t"
 166                          "casb %0,%1,%2\n\t"
 167                          "jne 1b"
 168                          : "=&d" (x) : "d" (x), "m" (*__xg(ptr)) : "memory");
 169                 break;
 170             case 2:
 171                 __asm__ __volatile__
 172                         ("movew %2,%0\n\t"
 173                          "1:\n\t"
 174                          "casw %0,%1,%2\n\t"
 175                          "jne 1b"
 176                          : "=&d" (x) : "d" (x), "m" (*__xg(ptr)) : "memory");
 177                 break;
 178             case 4:
 179                 __asm__ __volatile__
 180                         ("movel %2,%0\n\t"
 181                          "1:\n\t"
 182                          "casl %0,%1,%2\n\t"
 183                          "jne 1b"
 184                          : "=&d" (x) : "d" (x), "m" (*__xg(ptr)) : "memory");
 185                 break;
 186         }
 187         return x;
 188 }
 189 #endif
 190
 191 #include <asm-generic/cmpxchg-local.h>
 192
 193 /*
 194  * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
 195  * them available.
 196  */
 197 #define cmpxchg_local(ptr, o, n)                                               \
 198         ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
 199                         (unsigned long)(n), sizeof(*(ptr))))
 200 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
 201
 202 #ifndef CONFIG_SMP
 203 #include <asm-generic/cmpxchg.h>
 204 #endif
 205
 206 #define arch_align_stack(x) (x)
 207
 208
 209 static inline int irqs_disabled_flags(unsigned long flags)
 210 {
 211         if (flags & 0x0700)
 212                 return 0;
 213         else
 214                 return 1;
 215 }
 216
 217 #endif /* _M68KNOMMU_SYSTEM_H */