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 HAVE_FUNC_ATTRIBUTE_VISIBIITY
  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
  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
 101 entry_get_public(int slot)
 102 {
 103    return (mapi_func) (x86_entry_start + slot * 16);
 104 }
 105
 106 void
 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
 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 */