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   1 #ifndef __ASM_SH_SYSTEM_H
   2 #define __ASM_SH_SYSTEM_H
   3
   4 /*
   5  * Copyright (C) 1999, 2000  Niibe Yutaka  &  Kaz Kojima
   6  * Copyright (C) 2002 Paul Mundt
   7  */
   8
   9 #include <linux/irqflags.h>
  10 #include <linux/compiler.h>
  11 #include <asm/types.h>
  12 #include <asm/ptrace.h>
  13
  14 /*
  15  *      switch_to() should switch tasks to task nr n, first
  16  */
  17
  18 #define switch_to(prev, next, last) do {                                \
  19  struct task_struct *__last;                                            \
  20  register unsigned long *__ts1 __asm__ ("r1") = &prev->thread.sp;       \
  21  register unsigned long *__ts2 __asm__ ("r2") = &prev->thread.pc;       \
  22  register unsigned long *__ts4 __asm__ ("r4") = (unsigned long *)prev;  \
  23  register unsigned long *__ts5 __asm__ ("r5") = (unsigned long *)next;  \
  24  register unsigned long *__ts6 __asm__ ("r6") = &next->thread.sp;       \
  25  register unsigned long __ts7 __asm__ ("r7") = next->thread.pc;         \
  26  __asm__ __volatile__ (".balign 4\n\t"                                  \
  27                        "stc.l   gbr, @-r15\n\t"                         \
  28                        "sts.l   pr, @-r15\n\t"                          \
  29                        "mov.l   r8, @-r15\n\t"                          \
  30                        "mov.l   r9, @-r15\n\t"                          \
  31                        "mov.l   r10, @-r15\n\t"                         \
  32                        "mov.l   r11, @-r15\n\t"                         \
  33                        "mov.l   r12, @-r15\n\t"                         \
  34                        "mov.l   r13, @-r15\n\t"                         \
  35                        "mov.l   r14, @-r15\n\t"                         \
  36                        "mov.l   r15, @r1        ! save SP\n\t"          \
  37                        "mov.l   @r6, r15        ! change to new stack\n\t" \
  38                        "mova    1f, %0\n\t"                             \
  39                        "mov.l   %0, @r2         ! save PC\n\t"          \
  40                        "mov.l   2f, %0\n\t"                             \
  41                        "jmp     @%0             ! call __switch_to\n\t" \
  42                        " lds    r7, pr          !  with return to new PC\n\t" \
  43                        ".balign 4\n"                                    \
  44                        "2:\n\t"                                         \
  45                        ".long   __switch_to\n"                          \
  46                        "1:\n\t"                                         \
  47                        "mov.l   @r15+, r14\n\t"                         \
  48                        "mov.l   @r15+, r13\n\t"                         \
  49                        "mov.l   @r15+, r12\n\t"                         \
  50                        "mov.l   @r15+, r11\n\t"                         \
  51                        "mov.l   @r15+, r10\n\t"                         \
  52                        "mov.l   @r15+, r9\n\t"                          \
  53                        "mov.l   @r15+, r8\n\t"                          \
  54                        "lds.l   @r15+, pr\n\t"                          \
  55                        "ldc.l   @r15+, gbr\n\t"                         \
  56                        : "=z" (__last)                                  \
  57                        : "r" (__ts1), "r" (__ts2), "r" (__ts4),         \
  58                          "r" (__ts5), "r" (__ts6), "r" (__ts7)          \
  59                        : "r3", "t");                                    \
  60         last = __last;                                                  \
  61 } while (0)
  62
  63 /*
  64  * On SMP systems, when the scheduler does migration-cost autodetection,
  65  * it needs a way to flush as much of the CPU's caches as possible.
  66  *
  67  * TODO: fill this in!
  68  */
  69 static inline void sched_cacheflush(void)
  70 {
  71 }
  72
  73 #ifdef CONFIG_CPU_SH4A
  74 #define __icbi()                        \
  75 {                                       \
  76         unsigned long __addr;           \
  77         __addr = 0xa8000000;            \
  78         __asm__ __volatile__(           \
  79                 "icbi   %0\n\t"         \
  80                 : /* no output */       \
  81                 : "m" (__m(__addr)));   \
  82 }
  83 #endif
  84
  85 /*
  86  * A brief note on ctrl_barrier(), the control register write barrier.
  87  *
  88  * Legacy SH cores typically require a sequence of 8 nops after
  89  * modification of a control register in order for the changes to take
  90  * effect. On newer cores (like the sh4a and sh5) this is accomplished
  91  * with icbi.
  92  *
  93  * Also note that on sh4a in the icbi case we can forego a synco for the
  94  * write barrier, as it's not necessary for control registers.
  95  *
  96  * Historically we have only done this type of barrier for the MMUCR, but
  97  * it's also necessary for the CCR, so we make it generic here instead.
  98  */
  99 #ifdef CONFIG_CPU_SH4A
 100 #define mb()            __asm__ __volatile__ ("synco": : :"memory")
 101 #define rmb()           mb()
 102 #define wmb()           __asm__ __volatile__ ("synco": : :"memory")
 103 #define ctrl_barrier()  __icbi()
 104 #define read_barrier_depends()  do { } while(0)
 105 #else
 106 #define mb()            __asm__ __volatile__ ("": : :"memory")
 107 #define rmb()           mb()
 108 #define wmb()           __asm__ __volatile__ ("": : :"memory")
 109 #define ctrl_barrier()  __asm__ __volatile__ ("nop;nop;nop;nop;nop;nop;nop;nop")
 110 #define read_barrier_depends()  do { } while(0)
 111 #endif
 112
 113 #ifdef CONFIG_SMP
 114 #define smp_mb()        mb()
 115 #define smp_rmb()       rmb()
 116 #define smp_wmb()       wmb()
 117 #define smp_read_barrier_depends()      read_barrier_depends()
 118 #else
 119 #define smp_mb()        barrier()
 120 #define smp_rmb()       barrier()
 121 #define smp_wmb()       barrier()
 122 #define smp_read_barrier_depends()      do { } while(0)
 123 #endif
 124
 125 #define set_mb(var, value) do { xchg(&var, value); } while (0)
 126
 127 /*
 128  * Jump to P2 area.
 129  * When handling TLB or caches, we need to do it from P2 area.
 130  */
 131 #define jump_to_P2()                    \
 132 do {                                    \
 133         unsigned long __dummy;          \
 134         __asm__ __volatile__(           \
 135                 "mov.l  1f, %0\n\t"     \
 136                 "or     %1, %0\n\t"     \
 137                 "jmp    @%0\n\t"        \
 138                 " nop\n\t"              \
 139                 ".balign 4\n"           \
 140                 "1:     .long 2f\n"     \
 141                 "2:"                    \
 142                 : "=&r" (__dummy)       \
 143                 : "r" (0x20000000));    \
 144 } while (0)
 145
 146 /*
 147  * Back to P1 area.
 148  */
 149 #define back_to_P1()                                    \
 150 do {                                                    \
 151         unsigned long __dummy;                          \
 152         ctrl_barrier();                                 \
 153         __asm__ __volatile__(                           \
 154                 "mov.l  1f, %0\n\t"                     \
 155                 "jmp    @%0\n\t"                        \
 156                 " nop\n\t"                              \
 157                 ".balign 4\n"                           \
 158                 "1:     .long 2f\n"                     \
 159                 "2:"                                    \
 160                 : "=&r" (__dummy));                     \
 161 } while (0)
 162
 163 static inline unsigned long xchg_u32(volatile u32 *m, unsigned long val)
 164 {
 165         unsigned long flags, retval;
 166
 167         local_irq_save(flags);
 168         retval = *m;
 169         *m = val;
 170         local_irq_restore(flags);
 171         return retval;
 172 }
 173
 174 static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val)
 175 {
 176         unsigned long flags, retval;
 177
 178         local_irq_save(flags);
 179         retval = *m;
 180         *m = val & 0xff;
 181         local_irq_restore(flags);
 182         return retval;
 183 }
 184
 185 extern void __xchg_called_with_bad_pointer(void);
 186
 187 #define __xchg(ptr, x, size)                            \
 188 ({                                                      \
 189         unsigned long __xchg__res;                      \
 190         volatile void *__xchg_ptr = (ptr);              \
 191         switch (size) {                                 \
 192         case 4:                                         \
 193                 __xchg__res = xchg_u32(__xchg_ptr, x);  \
 194                 break;                                  \
 195         case 1:                                         \
 196                 __xchg__res = xchg_u8(__xchg_ptr, x);   \
 197                 break;                                  \
 198         default:                                        \
 199                 __xchg_called_with_bad_pointer();       \
 200                 __xchg__res = x;                        \
 201                 break;                                  \
 202         }                                               \
 203                                                         \
 204         __xchg__res;                                    \
 205 })
 206
 207 #define xchg(ptr,x)     \
 208         ((__typeof__(*(ptr)))__xchg((ptr),(unsigned long)(x), sizeof(*(ptr))))
 209
 210 static inline unsigned long __cmpxchg_u32(volatile int * m, unsigned long old,
 211         unsigned long new)
 212 {
 213         __u32 retval;
 214         unsigned long flags;
 215
 216         local_irq_save(flags);
 217         retval = *m;
 218         if (retval == old)
 219                 *m = new;
 220         local_irq_restore(flags);       /* implies memory barrier  */
 221         return retval;
 222 }
 223
 224 /* This function doesn't exist, so you'll get a linker error
 225  * if something tries to do an invalid cmpxchg(). */
 226 extern void __cmpxchg_called_with_bad_pointer(void);
 227
 228 #define __HAVE_ARCH_CMPXCHG 1
 229
 230 static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old,
 231                 unsigned long new, int size)
 232 {
 233         switch (size) {
 234         case 4:
 235                 return __cmpxchg_u32(ptr, old, new);
 236         }
 237         __cmpxchg_called_with_bad_pointer();
 238         return old;
 239 }
 240
 241 #define cmpxchg(ptr,o,n)                                                 \
 242   ({                                                                     \
 243      __typeof__(*(ptr)) _o_ = (o);                                       \
 244      __typeof__(*(ptr)) _n_ = (n);                                       \
 245      (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,           \
 246                                     (unsigned long)_n_, sizeof(*(ptr))); \
 247   })
 248
 249 extern void die(const char *str, struct pt_regs *regs, long err) __attribute__ ((noreturn));
 250
 251 extern void *set_exception_table_vec(unsigned int vec, void *handler);
 252
 253 static inline void *set_exception_table_evt(unsigned int evt, void *handler)
 254 {
 255         return set_exception_table_vec(evt >> 5, handler);
 256 }
 257
 258 /* XXX
 259  * disable hlt during certain critical i/o operations
 260  */
 261 #define HAVE_DISABLE_HLT
 262 void disable_hlt(void);
 263 void enable_hlt(void);
 264
 265 #define arch_align_stack(x) (x)
 266
 267 #endif