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futex.h

#ifndef _ASM_POWERPC_FUTEX_H
#define _ASM_POWERPC_FUTEX_H

#ifdef __KERNEL__

#include <linux/futex.h>
#include <linux/uaccess.h>
#include <asm/errno.h>
#include <asm/synch.h>
#include <asm/asm-compat.h>

#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
  __asm__ __volatile ( \
      LWSYNC_ON_SMP \
"1:   lwarx %0,0,%2\n" \
      insn \
      PPC405_ERR77(0, %2) \
"2:   stwcx.      %1,0,%2\n" \
      "bne- 1b\n" \
      "li   %1,0\n" \
"3:   .section .fixup,\"ax\"\n" \
"4:   li    %1,%3\n" \
      "b    3b\n" \
      ".previous\n" \
      ".section __ex_table,\"a\"\n" \
      ".align 3\n" \
      PPC_LONG "1b,4b,2b,4b\n" \
      ".previous" \
      : "=&r" (oldval), "=&r" (ret) \
      : "b" (uaddr), "i" (-EFAULT), "1" (oparg) \
      : "cr0", "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("", ret, oldval, uaddr, oparg);
            break;
      case FUTEX_OP_ADD:
            __futex_atomic_op("add %1,%0,%1\n", ret, oldval, uaddr, oparg);
            break;
      case FUTEX_OP_OR:
            __futex_atomic_op("or %1,%0,%1\n", ret, oldval, uaddr, oparg);
            break;
      case FUTEX_OP_ANDN:
            __futex_atomic_op("andc %1,%0,%1\n", ret, oldval, uaddr, oparg);
            break;
      case FUTEX_OP_XOR:
            __futex_atomic_op("xor %1,%0,%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;

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

        __asm__ __volatile__ (
        LWSYNC_ON_SMP
"1:     lwarx   %0,0,%2         # futex_atomic_cmpxchg_inatomic\n\
        cmpw    0,%0,%3\n\
        bne-    3f\n"
        PPC405_ERR77(0,%2)
"2:     stwcx.  %4,0,%2\n\
        bne-    1b\n"
        ISYNC_ON_SMP
"3:   .section .fixup,\"ax\"\n\
4:    li    %0,%5\n\
      b     3b\n\
      .previous\n\
      .section __ex_table,\"a\"\n\
      .align 3\n\
      " PPC_LONG "1b,4b,2b,4b\n\
      .previous" \
        : "=&r" (prev), "+m" (*uaddr)
        : "r" (uaddr), "r" (oldval), "r" (newval), "i" (-EFAULT)
        : "cc", "memory");

        return prev;
}

#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_FUTEX_H */

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