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 __CET__
31 #define ENDBR "endbr32\n\t"
32 #else
33 #define ENDBR
34 #endif
35
36 #ifdef HAVE_FUNC_ATTRIBUTE_VISIBILITY
37 #define HIDDEN __attribute__((visibility("hidden")))
38 #else
39 #define HIDDEN
40 #endif
41
42 #define X86_ENTRY_SIZE 32
43
44 __asm__(".text");
45
46 __asm__("x86_current_tls:\n\t"
47 "call 1f\n"
48 "1:\n\t"
49 "popl %eax\n\t"
50 "addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %eax\n\t"
51 "movl " ENTRY_CURRENT_TABLE "@GOTNTPOFF(%eax), %eax\n\t"
52 "ret");
53
54 #ifndef GLX_X86_READONLY_TEXT
55 __asm__(".section wtext, \"awx\", @progbits");
56 #endif /* GLX_X86_READONLY_TEXT */
57
58 __asm__(".balign 16\n"
59 "x86_entry_start:");
60
61 #define STUB_ASM_ENTRY(func) \
62 ".globl " func "\n" \
63 ".type " func ", @function\n" \
64 ".balign 16\n" \
65 func ":"
66
67 #define STUB_ASM_CODE(slot) \
68 ENDBR \
69 "call 1f\n" \
70 "1:\n\t" \
71 "popl %eax\n\t" \
72 "addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %eax\n\t" \
73 "movl " ENTRY_CURRENT_TABLE "@GOTNTPOFF(%eax), %eax\n\t" \
74 "movl %gs:(%eax), %eax\n\t" \
75 "jmp *(4 * " slot ")(%eax)"
76
77 #define MAPI_TMP_STUB_ASM_GCC
78 #include "mapi_tmp.h"
79
80 #ifndef GLX_X86_READONLY_TEXT
81 __asm__(".balign 16\n"
82 "x86_entry_end:");
83 __asm__(".text");
84 #endif /* GLX_X86_READONLY_TEXT */
85
86 #ifndef MAPI_MODE_BRIDGE
87
88 #include "u_execmem.h"
89
90 extern unsigned long
91 x86_current_tls();
92
93 extern char x86_entry_start[] HIDDEN;
94 extern char x86_entry_end[] HIDDEN;
95
96 static inline mapi_func
97 entry_generate_or_patch(int, char *, size_t);
98
99 void
entry_patch_public(void)100 entry_patch_public(void)
101 {
102 #ifndef GLX_X86_READONLY_TEXT
103 char *entry;
104 int slot = 0;
105 for (entry = x86_entry_start; entry < x86_entry_end;
106 entry += X86_ENTRY_SIZE, ++slot)
107 entry_generate_or_patch(slot, entry, X86_ENTRY_SIZE);
108 #endif
109 }
110
111 mapi_func
entry_get_public(int slot)112 entry_get_public(int slot)
113 {
114 return (mapi_func) (x86_entry_start + slot * X86_ENTRY_SIZE);
115 }
116
117 void
entry_patch(mapi_func entry,int slot)118 entry_patch(mapi_func entry, int slot)
119 {
120 char *code = (char *) entry;
121 *((unsigned long *) (code + 8)) = slot * sizeof(mapi_func);
122 }
123
124 static inline mapi_func
entry_generate_or_patch(int slot,char * code,size_t size)125 entry_generate_or_patch(int slot, char *code, size_t size)
126 {
127 const char code_templ[16] = {
128 0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, /* movl %gs:0x0, %eax */
129 0xff, 0xa0, 0x34, 0x12, 0x00, 0x00, /* jmp *0x1234(%eax) */
130 0x90, 0x90, 0x90, 0x90 /* nop's */
131 };
132 mapi_func entry;
133
134 if (code == NULL) {
135 size = sizeof(code_templ);
136 code = u_execmem_alloc(size);
137 }
138 if (!code || size < sizeof(code_templ))
139 return NULL;
140
141 memcpy(code, code_templ, sizeof(code_templ));
142
143 *((unsigned long *) (code + 2)) = x86_current_tls();
144 entry = (mapi_func) code;
145 entry_patch(entry, slot);
146
147 return entry;
148 }
149
150 mapi_func
entry_generate(int slot)151 entry_generate(int slot)
152 {
153 return entry_generate_or_patch(slot, NULL, 0);
154 }
155
156 #endif /* MAPI_MODE_BRIDGE */
157