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futex.h

#ifndef _ASM_FUTEX_H
#define _ASM_FUTEX_H

#include <linux/futex.h>
#include <linux/uaccess.h>
#include <asm/errno.h>
#include <asm/system.h>

#define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \
do {                                                  \
      register unsigned long r8 __asm ("r8") = 0;                 \
      __asm__ __volatile__(                                 \
            "     mf;;                          \n"   \
            "[1:] "     insn ";;                      \n"   \
            "     .xdata4 \"__ex_table\", 1b-., 2f-.  \n"   \
            "[2:]"                                          \
            : "+r" (r8), "=r" (oldval)                      \
            : "r" (uaddr), "r" (oparg)                      \
            : "memory");                                    \
      ret = r8;                                       \
} while (0)

#define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \
do {                                                  \
      register unsigned long r8 __asm ("r8") = 0;                 \
      int val, newval;                                \
      do {                                            \
            __asm__ __volatile__(                           \
                  "     mf;;                      \n" \
                  "[1:] ld4 %3=[%4];;                   \n" \
                  "     mov %2=%3                 \n" \
                        insn  ";;                 \n" \
                  "     mov ar.ccv=%2;;                 \n" \
                  "[2:] cmpxchg4.acq %1=[%4],%3,ar.ccv;;  \n"     \
                  "     .xdata4 \"__ex_table\", 1b-., 3f-.\n"     \
                  "     .xdata4 \"__ex_table\", 2b-., 3f-.\n"     \
                  "[3:]"                                    \
                  : "+r" (r8), "=r" (val), "=&r" (oldval),  \
                     "=&r" (newval)                   \
                  : "r" (uaddr), "r" (oparg)                \
                  : "memory");                              \
            if (unlikely (r8))                              \
                  break;                                    \
      } while (unlikely (val != oldval));                   \
      ret = r8;                                       \
} while (0)

static inline int
futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
{
      int op = (encoded_op >> 28) & 7;
      int cmp = (encoded_op >> 24) & 15;
      int oparg = (encoded_op << 8) >> 20;
      int cmparg = (encoded_op << 20) >> 20;
      int oldval = 0, ret;
      if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
            oparg = 1 << oparg;

      if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
            return -EFAULT;

      pagefault_disable();

      switch (op) {
      case FUTEX_OP_SET:
            __futex_atomic_op1("xchg4 %1=[%2],%3", ret, oldval, uaddr,
                           oparg);
            break;
      case FUTEX_OP_ADD:
            __futex_atomic_op2("add %3=%3,%5", ret, oldval, uaddr, oparg);
            break;
      case FUTEX_OP_OR:
            __futex_atomic_op2("or %3=%3,%5", ret, oldval, uaddr, oparg);
            break;
      case FUTEX_OP_ANDN:
            __futex_atomic_op2("and %3=%3,%5", ret, oldval, uaddr,
                           ~oparg);
            break;
      case FUTEX_OP_XOR:
            __futex_atomic_op2("xor %3=%3,%5", ret, oldval, uaddr, oparg);
            break;
      default:
            ret = -ENOSYS;
      }

      pagefault_enable();

      if (!ret) {
            switch (cmp) {
            case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
            case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
            case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
            case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
            case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
            case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
            default: ret = -ENOSYS;
            }
      }
      return ret;
}

static inline int
futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
{
      if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
            return -EFAULT;

      {
            register unsigned long r8 __asm ("r8");
            __asm__ __volatile__(
                  "     mf;;                          \n"
                  "     mov ar.ccv=%3;;                     \n"
                  "[1:] cmpxchg4.acq %0=[%1],%2,ar.ccv            \n"
                  "     .xdata4 \"__ex_table\", 1b-., 2f-.  \n"
                  "[2:]"
                  : "=r" (r8)
                  : "r" (uaddr), "r" (newval),
                    "rO" ((long) (unsigned) oldval)
                  : "memory");
            return r8;
      }
}

#endif /* _ASM_FUTEX_H */

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