src/mapi/entry_x86_tls.h

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.9
   4  *
   5  * Copyright (C) 2010 LunarG Inc.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  22  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  23  * DEALINGS IN THE SOFTWARE.
  24  *
  25  * Authors:
  26  *    Chia-I Wu <olv@lunarg.com>
  27  */
  28
  29 #include <string.h>
  30 #include "u_macros.h"
  31
  32 #ifdef __linux__
  33 __asm__(".section .note.ABI-tag, \"a\"\n\t"
  34         ".p2align 2\n\t"
  35         ".long 1f - 0f\n\t"      /* name length */
  36         ".long 3f - 2f\n\t"      /* data length */
  37         ".long 1\n\t"            /* note length */
  38         "0: .asciz \"GNU\"\n\t"  /* vendor name */
  39         "1: .p2align 2\n\t"
  40         "2: .long 0\n\t"         /* note data: the ABI tag */
  41         ".long 2,4,20\n\t"       /* Minimum kernel version w/TLS */
  42         "3: .p2align 2\n\t");    /* pad out section */
  43 #endif /* __linux__ */
  44
  45 __asm__(".text");
  46
  47 __asm__("x86_current_tls:\n\t"
  48         "call 1f\n"
  49         "1:\n\t"
  50         "popl %eax\n\t"
  51         "addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %eax\n\t"
  52         "movl " ENTRY_CURRENT_TABLE "@GOTNTPOFF(%eax), %eax\n\t"
  53         "ret");
  54
  55 #ifndef GLX_X86_READONLY_TEXT
  56 __asm__(".section wtext, \"awx\", @progbits");
  57 #endif /* GLX_X86_READONLY_TEXT */
  58
  59 __asm__(".balign 16\n"
  60         "x86_entry_start:");
  61
  62 #define STUB_ASM_ENTRY(func)     \
  63    ".globl " func "\n"           \
  64    ".type " func ", @function\n" \
  65    ".balign 16\n"                \
  66    func ":"
  67
  68 #define STUB_ASM_CODE(slot)      \
  69    "call x86_current_tls\n\t"    \
  70    "movl %gs:(%eax), %eax\n\t"   \
  71    "jmp *(4 * " slot ")(%eax)"
  72
  73 #define MAPI_TMP_STUB_ASM_GCC
  74 #include "mapi_tmp.h"
  75
  76 #ifndef GLX_X86_READONLY_TEXT
  77 __asm__(".balign 16\n"
  78         "x86_entry_end:");
  79 __asm__(".text");
  80 #endif /* GLX_X86_READONLY_TEXT */
  81
  82 #ifndef MAPI_MODE_BRIDGE
  83
  84 #include "u_execmem.h"
  85
  86 extern unsigned long
  87 x86_current_tls();
  88
  89 static char x86_entry_start[];
  90 static char x86_entry_end[];
  91
  92 void
  93 entry_patch_public(void)
  94 {
  95 #ifndef GLX_X86_READONLY_TEXT
  96    char patch[8] = {
  97       0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, /* movl %gs:0x0, %eax */
  98       0x90, 0x90                          /* nop's */
  99    };
 100    char *entry;
 101
 102    *((unsigned long *) (patch + 2)) = x86_current_tls();
 103
 104    for (entry = x86_entry_start; entry < x86_entry_end; entry += 16)
 105       memcpy(entry, patch, sizeof(patch));
 106 #endif
 107 }
 108
 109 mapi_func
 110 entry_get_public(int slot)
 111 {
 112    return (mapi_func) (x86_entry_start + slot * 16);
 113 }
 114
 115 void
 116 entry_patch(mapi_func entry, int slot)
 117 {
 118    char *code = (char *) entry;
 119    *((unsigned long *) (code + 8)) = slot * sizeof(mapi_func);
 120 }
 121
 122 mapi_func
 123 entry_generate(int slot)
 124 {
 125    const char code_templ[16] = {
 126       0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, /* movl %gs:0x0, %eax */
 127       0xff, 0xa0, 0x34, 0x12, 0x00, 0x00, /* jmp *0x1234(%eax) */
 128       0x90, 0x90, 0x90, 0x90              /* nop's */
 129    };
 130    void *code;
 131    mapi_func entry;
 132
 133    code = u_execmem_alloc(sizeof(code_templ));
 134    if (!code)
 135       return NULL;
 136
 137    memcpy(code, code_templ, sizeof(code_templ));
 138
 139    *((unsigned long *) (code + 2)) = x86_current_tls();
 140    entry = (mapi_func) code;
 141    entry_patch(entry, slot);
 142
 143    return entry;
 144 }
 145
 146 #endif /* MAPI_MODE_BRIDGE */