kernel/arch/sh/include/asm/atomic-llsc.h

   1 #ifndef __ASM_SH_ATOMIC_LLSC_H
   2 #define __ASM_SH_ATOMIC_LLSC_H
   3
   4 /*
   5  * SH-4A note:
   6  *
   7  * We basically get atomic_xxx_return() for free compared with
   8  * atomic_xxx(). movli.l/movco.l require r0 due to the instruction
   9  * encoding, so the retval is automatically set without having to
  10  * do any special work.
  11  */
  12 /*
  13  * To get proper branch prediction for the main line, we must branch
  14  * forward to code at the end of this object's .text section, then
  15  * branch back to restart the operation.
  16  */
  17
  18 #define ATOMIC_OP(op)                                                   \
  19 static inline void atomic_##op(int i, atomic_t *v)                      \
  20 {                                                                       \
  21         unsigned long tmp;                                              \
  22                                                                         \
  23         __asm__ __volatile__ (                                          \
  24 "1:     movli.l @%2, %0         ! atomic_" #op "\n"                     \
  25 "       " #op " %1, %0                          \n"                     \
  26 "       movco.l %0, @%2                         \n"                     \
  27 "       bf      1b                              \n"                     \
  28         : "=&z" (tmp)                                                   \
  29         : "r" (i), "r" (&v->counter)                                    \
  30         : "t");                                                         \
  31 }
  32
  33 #define ATOMIC_OP_RETURN(op)                                            \
  34 static inline int atomic_##op##_return(int i, atomic_t *v)              \
  35 {                                                                       \
  36         unsigned long temp;                                             \
  37                                                                         \
  38         __asm__ __volatile__ (                                          \
  39 "1:     movli.l @%2, %0         ! atomic_" #op "_return \n"             \
  40 "       " #op " %1, %0                                  \n"             \
  41 "       movco.l %0, @%2                                 \n"             \
  42 "       bf      1b                                      \n"             \
  43 "       synco                                           \n"             \
  44         : "=&z" (temp)                                                  \
  45         : "r" (i), "r" (&v->counter)                                    \
  46         : "t");                                                         \
  47                                                                         \
  48         return temp;                                                    \
  49 }
  50
  51 #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op)
  52
  53 ATOMIC_OPS(add)
  54 ATOMIC_OPS(sub)
  55 ATOMIC_OP(and)
  56 ATOMIC_OP(or)
  57 ATOMIC_OP(xor)
  58
  59 #undef ATOMIC_OPS
  60 #undef ATOMIC_OP_RETURN
  61 #undef ATOMIC_OP
  62
  63 #endif /* __ASM_SH_ATOMIC_LLSC_H */