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