1 files changed, 98 insertions, 0 deletions

diff --git a/include/asm-x86_64/futex.h b/include/asm-x86_64/futex.h
new file mode 100644
index 000000000000..8602c09bf89e
--- /dev/null
+++ b/include/asm-x86_64/futex.h
@@ -0,0 +1,98 @@
+#ifndef _ASM_FUTEX_H
+#define _ASM_FUTEX_H
+
+#ifdef __KERNEL__
+
+#include <linux/futex.h>
+#include <asm/errno.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+
+#define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \
+  __asm__ __volatile (                                          \
+"1:     " insn "\n"                                             \
+"2:     .section .fixup,\"ax\"\n\
+3:      mov     %3, %1\n\
+        jmp     2b\n\
+        .previous\n\
+        .section __ex_table,\"a\"\n\
+        .align  8\n\
+        .quad   1b,3b\n\
+        .previous"                                              \
+        : "=r" (oldval), "=r" (ret), "=m" (*uaddr)              \
+        : "i" (-EFAULT), "m" (*uaddr), "0" (oparg), "1" (0))
+
+#define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \
+  __asm__ __volatile (                                          \
+"1:     movl    %2, %0\n\
+        movl    %0, %3\n"                                       \
+        insn "\n"                                               \
+"2:     " LOCK_PREFIX "cmpxchgl %3, %2\n\
+        jnz     1b\n\
+3:      .section .fixup,\"ax\"\n\
+4:      mov     %5, %1\n\
+        jmp     3b\n\
+        .previous\n\
+        .section __ex_table,\"a\"\n\
+        .align  8\n\
+        .quad   1b,4b,2b,4b\n\
+        .previous"                                              \
+        : "=&a" (oldval), "=&r" (ret), "=m" (*uaddr),           \
+          "=&r" (tem)                                           \
+        : "r" (oparg), "i" (-EFAULT), "m" (*uaddr), "1" (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, tem;
+        if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
+                oparg = 1 << oparg;
+
+        if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
+                return -EFAULT;
+
+        inc_preempt_count();
+
+        switch (op) {
+        case FUTEX_OP_SET:
+                __futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg);
+                break;
+        case FUTEX_OP_ADD:
+                __futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret, oldval,
+                                   uaddr, oparg);
+                break;
+        case FUTEX_OP_OR:
+                __futex_atomic_op2("orl %4, %3", ret, oldval, uaddr, oparg);
+                break;
+        case FUTEX_OP_ANDN:
+                __futex_atomic_op2("andl %4, %3", ret, oldval, uaddr, ~oparg);
+                break;
+        case FUTEX_OP_XOR:
+                __futex_atomic_op2("xorl %4, %3", ret, oldval, uaddr, oparg);
+                break;
+        default:
+                ret = -ENOSYS;
+        }
+
+        dec_preempt_count();
+
+        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;
+}
+
+#endif
+#endif