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
77 extern unsigned long
78 x86_current_tls();
79
80 extern char x86_entry_start[] HIDDEN;
81 extern char x86_entry_end[] HIDDEN;
82
83 void
entry_patch_public(void)84 entry_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
100 mapi_func
entry_get_public(int slot)101 entry_get_public(int slot)
102 {
103 return (mapi_func) (x86_entry_start + slot * 16);
104 }
105
106 void
entry_patch(mapi_func entry,int slot)107 entry_patch(mapi_func entry, int slot)
108 {
109 char *code = (char *) entry;
110 *((unsigned long *) (code + 8)) = slot * sizeof(mapi_func);
111 }
112
113 mapi_func
entry_generate(int slot)114 entry_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