1/* $NetBSD: pnpbioscall.S,v 1.3 2018/07/14 14:29:40 maxv Exp $ */
2/*
3 * Copyright (c) 1999
4 *        Matthias Drochner.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions, and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <machine/asm.h>
29__KERNEL_RCSID(0, "$NetBSD: pnpbioscall.S,v 1.3 2018/07/14 14:29:40 maxv Exp $");
30
31#include "assym.h"
32#include <machine/segments.h>
33
34          .data
35saveesp:
36          .space    4
37
38ENTRY(pnpbioscall)
39          pushl     %ebp
40          movl      %esp, %ebp
41          /*
42           * disable interrupts - our handlers can't deal with frames of the
43           * segment we are calling, and the BIOS can't use our IDT anyway
44           */
45          pushfl
46          cli
47
48          /* call pnpbiostramp() */
49          lcall     $GSEL(GPNPBIOSTRAMP_SEL, SEL_KPL), $0
50
51          popfl
52          popl      %ebp
53          ret
54
55ENTRY(pnpbiostramp)
56          pushl     %ebx
57
58          /* save current stack pointer */
59          movl      %esp, %eax
60          movl      %eax, saveesp
61
62          /* switch to new stack */
63          movl      8(%ebp), %esp /* call argument */
64          movl      $GSEL(GPNPBIOSSCRATCH_SEL, SEL_KPL), %eax
65          mov       %ax, %ss
66
67          /* fake the call return address (16-bit frame) */
68          mov       %cs, %ax
69          push      %ax
70          movl      $(1f - _C_LABEL(pnpbiostramp)), %eax
71          push      %ax
72
73          /* do a long jump */
74          pushl     $GSEL(GPNPBIOSCODE_SEL, SEL_KPL)
75          pushl     (_C_LABEL(pnpbios_entry))
76#if 1
77          /* paranoia: don't pass our ds */
78          movl      $GSEL(GPNPBIOSSCRATCH_SEL, SEL_KPL), %eax
79          mov       %ax, %ds
80#endif
81          lret
82
831:        /* returned from BIOS call */
84          movl      $GSEL(GDATA_SEL, SEL_KPL), %ebx
85#if 1
86          mov       %bx, %ds
87#endif
88          /* back to old stack */
89          mov       %bx, %ss
90          movl      saveesp, %ebx
91          movl      %ebx, %esp
92
93          popl      %ebx
94          lret
95          .globl _C_LABEL(epnpbiostramp)
96_C_LABEL(epnpbiostramp):
97