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| 1 /* | |
| 2 * Copyright 2008, Google Inc. | |
| 3 * All rights reserved. | |
| 4 * | |
| 5 * Redistribution and use in source and binary forms, with or without | |
| 6 * modification, are permitted provided that the following conditions are | |
| 7 * met: | |
| 8 * | |
| 9 * * Redistributions of source code must retain the above copyright | |
| 10 * notice, this list of conditions and the following disclaimer. | |
| 11 * * Redistributions in binary form must reproduce the above | |
| 12 * copyright notice, this list of conditions and the following disclaimer | |
| 13 * in the documentation and/or other materials provided with the | |
| 14 * distribution. | |
| 15 * * Neither the name of Google Inc. nor the names of its | |
| 16 * contributors may be used to endorse or promote products derived from | |
| 17 * this software without specific prior written permission. | |
| 18 * | |
| 19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
| 22 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
| 23 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
| 24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
| 25 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
| 29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 30 */ | |
| 31 | |
| 32 /* Native Client crt0 startup code */ | |
| 33 /* FIXME(khim): split x86 and x86-64 version */ | |
| 34 | |
| 35 .data | |
| 36 .globl environ | |
| 37 | |
| 38 .text | |
| 39 .p2align NACLENTRYALIGN,0xf4 | |
| 40 | |
| 41 .global _start | |
| 42 _start: | |
| 43 /* | |
| 44 * The i386 ELF ABI specifies that on entry the stack looks like: | |
| 45 * -------------------------------- | |
| 46 * | Unspecified | | |
| 47 * -------------------------------- | |
| 48 * | Information block, including | | |
| 49 * | argument strings, | | |
| 50 * | environment strings, | | |
| 51 * | auxiliary information | | |
| 52 * | ... | | |
| 53 * | (size varies) | | |
| 54 * -------------------------------- | |
| 55 * | Unspecified | | |
| 56 * -------------------------------- | |
| 57 * | Null auxiliary vector entry | | |
| 58 * -------------------------------- | |
| 59 * | Auxiliary vector | | |
| 60 * | ... | | |
| 61 * | (2-word entries) | | |
| 62 * -------------------------------- | |
| 63 * | 0 word | | |
| 64 * -------------------------------- | |
| 65 * | Environment pointers | | |
| 66 * | ... | | |
| 67 * | (one word each) | | |
| 68 * -------------------------------- | |
| 69 * | Argument pointers | | |
| 70 * | ... | | |
| 71 * 4(%esp) | (Argument count words) | | |
| 72 * -------------------------------- | |
| 73 * 0(%esp) | Argument count | | |
| 74 * -------------------------------- | |
| 75 * | Undefined | | |
| 76 * -------------------------------- | |
| 77 * TODO(sehr): fix stack alignments of atexit, _init, _fini, and | |
| 78 * exit. | |
| 79 */ | |
| 80 | |
| 81 /* | |
| 82 * The ABI uses a null frame pointer to say when to stop backtracing. | |
| 83 * In x86-64 case we don't need this because RBP handling is special | |
| 84 * and so loader will load proper value in RBP. | |
| 85 */ | |
| 86 #if !defined(__x86_64__) | |
| 87 xorl %ebp, %ebp | |
| 88 #endif | |
| 89 | |
| 90 /* | |
| 91 * Because we are going to align the stack 0mod16 for SSE2, | |
| 92 * We need to gather the argc, argv, and envp pointers before | |
| 93 * moving esp. | |
| 94 */ | |
| 95 #if defined(__x86_64__) | |
| 96 popq %rsi /* Remove argc from the top of the stack */ | |
| 97 movq %rsp, %rcx /* Save the argv pointer */ | |
| 98 #else | |
| 99 popl %esi /* Remove argc from the top of the stack */ | |
| 100 movl %esp, %ecx /* Save the argv pointer */ | |
| 101 #endif | |
| 102 | |
| 103 /* | |
| 104 * Finding envp requires skipping over argc+1 words. | |
| 105 */ | |
| 106 #if defined(__x86_64__) | |
| 107 /* NOTE(khim): we are using ILP32 model in x86-64 mode! */ | |
| 108 leal 4(%rsp, %rsi, 4), %ebx | |
| 109 #else | |
| 110 leal 4(%esp, %esi, 4), %ebx | |
| 111 #endif | |
| 112 | |
| 113 /* | |
| 114 * environ is initiallly set to point to the same location as envp. | |
| 115 * setenv, etc., may change this pointer later. | |
| 116 */ | |
| 117 #if defined(__x86_64__) | |
| 118 movl %ebx, environ(%rip) | |
| 119 #else | |
| 120 movl %ebx, environ | |
| 121 #endif | |
| 122 | |
| 123 /* | |
| 124 * Align the stack 0mod16, for SSE2 | |
| 125 */ | |
| 126 #if defined(__x86_64__) | |
| 127 andq $0xfffffffffffffff0, %rsp | |
| 128 #else | |
| 129 andl $0xfffffff0, %esp | |
| 130 #endif | |
| 131 | |
| 132 #if defined(__x86_64__) | |
| 133 /* | |
| 134 *Save the arguments in spare registers. | |
| 135 */ | |
| 136 movq %rsi, %r12 | |
| 137 movq %rcx, %r13 | |
| 138 movl %ebx, %r14d | |
| 139 #else | |
| 140 /* | |
| 141 * Push the arguments to main. | |
| 142 */ | |
| 143 pushl %ebp /* Padding to maintain 0mod16 alignment */ | |
| 144 pushl %ebx /* Push envp onto the stack */ | |
| 145 pushl %ecx /* Push argv onto the stack */ | |
| 146 pushl %esi /* Push argc back onto the stack */ | |
| 147 #endif | |
| 148 | |
| 149 /* | |
| 150 * Install the fini section for use at exit. The C++ static object | |
| 151 * destructors are invoked from here. | |
| 152 */ | |
| 153 #if defined(__x86_64__) | |
| 154 /* TODO(eaeltsin): replace _fini with __libc_fini_array! */ | |
| 155 leal _fini(%rip), %edi | |
| 156 call atexit | |
| 157 #else | |
| 158 subl $12, %esp /* Padding to maintain 0mod16 alignment */ | |
| 159 /* TODO(eaeltsin): replace _fini with __libc_fini_array! */ | |
| 160 pushl $_fini | |
| 161 call atexit | |
| 162 addl $16, %esp /* Pop parameter and padding */ | |
| 163 #endif | |
| 164 | |
| 165 /* | |
| 166 * Initialize the pthreads library. We need to do at least a minimal | |
| 167 * amount of initialization (e.g., set up gs) to allow thread local | |
| 168 * storage references to work. The default binding of the symbol | |
| 169 * is weak, replaced by the real pthread library initialization when | |
| 170 * present. | |
| 171 */ | |
| 172 call __pthread_initialize | |
| 173 | |
| 174 /* | |
| 175 * Install the pthread_shutdown call to be called at exit. | |
| 176 */ | |
| 177 #if defined(__x86_64__) | |
| 178 leal __pthread_shutdown(%rip), %edi | |
| 179 call atexit | |
| 180 #else | |
| 181 subl $12, %esp /* Padding to maintain 0mod16 alignment */ | |
| 182 pushl $__pthread_shutdown | |
| 183 call atexit | |
| 184 addl $16, %esp /* Pop parameter and padding */ | |
| 185 #endif | |
| 186 | |
| 187 /* | |
| 188 * Execute the init section before starting main. The C++ static | |
| 189 * object constructors are invoked from here. | |
| 190 */ | |
| 191 /* TODO(eaeltsin): replace _init with __libc_init_array! */ | |
| 192 call _init | |
| 193 | |
| 194 /* | |
| 195 * Invoke main, the start of the user's code. | |
| 196 */ | |
| 197 #if defined(__x86_64__) | |
| 198 movq %r12, %rdi | |
| 199 movq %r13, %rsi | |
| 200 movl %r14d, %edx | |
| 201 call main | |
| 202 movq %rax, %r12 /* Save return value for use by exit call. */ | |
| 203 #else | |
| 204 call main | |
| 205 subl $12, %esp /* Make space for the return value */ | |
| 206 pushl %eax /* Save return value for use by exit call. */ | |
| 207 #endif | |
| 208 | |
| 209 /* | |
| 210 * Call exit from the C library so atexit gets called, and the | |
| 211 * C++ destructors get run. This calls our exit routine below | |
| 212 * when it's done. | |
| 213 */ | |
| 214 #if defined(__x86_64__) | |
| 215 movq %r12, %rdi | |
| 216 call exit | |
| 217 #else | |
| 218 call exit | |
| 219 addl $32, %esp /* Clean up all the arguments */ | |
| 220 #endif | |
| 221 | |
| 222 halt_loop: | |
| 223 hlt | |
| 224 jmp halt_loop | |
| 225 | |
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Chromium Code Reviews
Issue 7276050:
Change startup ABI for untrusted code to be C-compatible (Closed)
Base URL: svn://svn.chromium.org/native_client/trunk/src/native_client