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futex.h

#ifndef _ASM_ALPHA_FUTEX_H
#define _ASM_ALPHA_FUTEX_H

#ifdef __KERNEL__

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

#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)  \
      __asm__ __volatile__(                           \
            __ASM_SMP_MB                              \
      "1:   ldl_l %0,0(%2)\n"                   \
            insn                                \
      "2:   stl_c %1,0(%2)\n"                   \
      "     beq   %1,4f\n"                      \
      "     mov   $31,%1\n"                     \
      "3:   .subsection 2\n"                    \
      "4:   br    1b\n"                         \
      "     .previous\n"                              \
      "     .section __ex_table,\"a\"\n"              \
      "     .long 1b-.\n"                             \
      "     lda   $31,3b-1b(%1)\n"              \
      "     .long 2b-.\n"                             \
      "     lda   $31,3b-2b(%1)\n"              \
      "     .previous\n"                              \
      :     "=&r" (oldval), "=&r"(ret)                \
      :     "r" (uaddr), "r"(oparg)                   \
      :     "memory")

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_op("mov %3,%1\n", ret, oldval, uaddr, oparg);
            break;
      case FUTEX_OP_ADD:
            __futex_atomic_op("addl %0,%3,%1\n", ret, oldval, uaddr, oparg);
            break;
      case FUTEX_OP_OR:
            __futex_atomic_op("or %0,%3,%1\n", ret, oldval, uaddr, oparg);
            break;
      case FUTEX_OP_ANDN:
            __futex_atomic_op("andnot %0,%3,%1\n", ret, oldval, uaddr, oparg);
            break;
      case FUTEX_OP_XOR:
            __futex_atomic_op("xor %0,%3,%1\n", 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)
{
      int prev, cmp;

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

      __asm__ __volatile__ (
            __ASM_SMP_MB
      "1:   ldl_l %0,0(%2)\n"
      "     cmpeq %0,%3,%1\n"
      "     beq   %1,3f\n"
      "     mov   %4,%1\n"
      "2:   stl_c %1,0(%2)\n"
      "     beq   %1,4f\n"
      "3:   .subsection 2\n"
      "4:   br    1b\n"
      "     .previous\n"
      "     .section __ex_table,\"a\"\n"
      "     .long 1b-.\n"
      "     lda   $31,3b-1b(%0)\n"
      "     .long 2b-.\n"
      "     lda   $31,3b-2b(%0)\n"
      "     .previous\n"
      :     "=&r"(prev), "=&r"(cmp)
      :     "r"(uaddr), "r"((long)oldval), "r"(newval)
      :     "memory");

      return prev;
}

#endif /* __KERNEL__ */
#endif /* _ASM_ALPHA_FUTEX_H */

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