src/ucontext/x86_64/_ctx_start.s

   1 /*
   2  * Copyright (c) 2007 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*
  25  * Copyright (c) 2001 Daniel Eischen <deischen@freebsd.org>
  26  * All rights reserved.
  27  *
  28  * Redistribution and use in source and binary forms, with or without
  29  * modification, are permitted provided that the following conditions
  30  * are met:
  31  * 1. Redistributions of source code must retain the above copyright
  32  *    notice, this list of conditions and the following disclaimer.
  33  * 2. Neither the name of the author nor the names of its contributors
  34  *    may be used to endorse or promote products derived from this software
  35  *    without specific prior written permission.
  36  *
  37  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  38  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  39  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  40  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  41  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  42  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  43  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  44  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  45  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  46  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  47  * SUCH DAMAGE.
  48  */
  49
  50 #if defined(__x86_64__)
  51
  52 #include <architecture/i386/asm_help.h>
  53
  54 /*
  55  * _ctx_start((void *func)(int arg1, ..., argn),
  56  *            int arg1, ..., argn, ucontext_t *ucp)
  57  *
  58  * %rdi         - func
  59  * %rsi         - arg1
  60  * %rdx         - arg2
  61  * %rcx         - arg3
  62  * %r8          - arg4
  63  * %r9          - arg5
  64  * WRONG!
  65  * (8*(n-6))(%rsp)              - argn
  66  * (8*(n + 1))(%rsp)    - ucp, %rbp setup to point here (base of stack)
  67  */
  68 TEXT
  69 .private_extern __ctx_start
  70 LABEL(__ctx_start)
  71         popq    %rax            /* accounted for in makecontext() */
  72         /* makecontext will simulate 6 parameters at least */
  73         /* Or it could just set these in the mcontext... */
  74         popq    %rdi
  75         popq    %rsi
  76         popq    %rdx
  77         popq    %rcx
  78         popq    %r8
  79         popq    %r9
  80
  81         callq   *%rax           /* call start function */
  82         movq    %r12, %rsp      /*
  83                                  * setup stack for completion routine;
  84                                  * ucp is now at top of stack
  85                                  */
  86         movq    (%rsp), %rdi
  87         CALL_EXTERN(__ctx_done) /* should never return */
  88         int $5                          /* trap */
  89
  90 #endif /* __x86_64__ */