src/mapi/entry_x86_tls.h

   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
 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
 112 entry_get_public(int slot)
 113 {
 114    return (mapi_func) (x86_entry_start + slot * X86_ENTRY_SIZE);
 115 }
 116
 117 void
 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
 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
 151 entry_generate(int slot)
 152 {
 153    return entry_generate_or_patch(slot, NULL, 0);
 154 }
 155
 156 #endif /* MAPI_MODE_BRIDGE */