1/*
2 * Mesa 3-D graphics library
3 *
4 * Copyright (C) 2010 LunarG Inc.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included
14 * in all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 * DEALINGS IN THE SOFTWARE.
23 *
24 * Authors:
25 *    Chia-I Wu <olv@lunarg.com>
26 */
27
28#include <string.h>
29
30#ifdef HAVE_FUNC_ATTRIBUTE_VISIBILITY
31#define HIDDEN __attribute__((visibility("hidden")))
32#else
33#define HIDDEN
34#endif
35
36__asm__(".text");
37
38__asm__("x86_current_tls:\n\t"
39	"call 1f\n"
40        "1:\n\t"
41        "popl %eax\n\t"
42	"addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %eax\n\t"
43	"movl " ENTRY_CURRENT_TABLE "@GOTNTPOFF(%eax), %eax\n\t"
44	"ret");
45
46#ifndef GLX_X86_READONLY_TEXT
47__asm__(".section wtext, \"awx\", @progbits");
48#endif /* GLX_X86_READONLY_TEXT */
49
50__asm__(".balign 16\n"
51        "x86_entry_start:");
52
53#define STUB_ASM_ENTRY(func)     \
54   ".globl " func "\n"           \
55   ".type " func ", @function\n" \
56   ".balign 16\n"                \
57   func ":"
58
59#define STUB_ASM_CODE(slot)      \
60   "call x86_current_tls\n\t"    \
61   "movl %gs:(%eax), %eax\n\t"   \
62   "jmp *(4 * " slot ")(%eax)"
63
64#define MAPI_TMP_STUB_ASM_GCC
65#include "mapi_tmp.h"
66
67#ifndef GLX_X86_READONLY_TEXT
68__asm__(".balign 16\n"
69        "x86_entry_end:");
70__asm__(".text");
71#endif /* GLX_X86_READONLY_TEXT */
72
73#ifndef MAPI_MODE_BRIDGE
74
75#include "u_execmem.h"
76
77extern unsigned long
78x86_current_tls();
79
80extern char x86_entry_start[] HIDDEN;
81extern char x86_entry_end[] HIDDEN;
82
83void
84entry_patch_public(void)
85{
86#ifndef GLX_X86_READONLY_TEXT
87   char patch[8] = {
88      0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, /* movl %gs:0x0, %eax */
89      0x90, 0x90                          /* nop's */
90   };
91   char *entry;
92
93   *((unsigned long *) (patch + 2)) = x86_current_tls();
94
95   for (entry = x86_entry_start; entry < x86_entry_end; entry += 16)
96      memcpy(entry, patch, sizeof(patch));
97#endif
98}
99
100mapi_func
101entry_get_public(int slot)
102{
103   return (mapi_func) (x86_entry_start + slot * 16);
104}
105
106void
107entry_patch(mapi_func entry, int slot)
108{
109   char *code = (char *) entry;
110   *((unsigned long *) (code + 8)) = slot * sizeof(mapi_func);
111}
112
113mapi_func
114entry_generate(int slot)
115{
116   const char code_templ[16] = {
117      0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, /* movl %gs:0x0, %eax */
118      0xff, 0xa0, 0x34, 0x12, 0x00, 0x00, /* jmp *0x1234(%eax) */
119      0x90, 0x90, 0x90, 0x90              /* nop's */
120   };
121   char *code;
122   mapi_func entry;
123
124   code = u_execmem_alloc(sizeof(code_templ));
125   if (!code)
126      return NULL;
127
128   memcpy(code, code_templ, sizeof(code_templ));
129
130   *((unsigned long *) (code + 2)) = x86_current_tls();
131   entry = (mapi_func) code;
132   entry_patch(entry, slot);
133
134   return entry;
135}
136
137#endif /* MAPI_MODE_BRIDGE */
138