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