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Diffstat (limited to 'sysdeps/x86_64/start.S')
| -rw-r--r-- | sysdeps/x86_64/start.S | 131 |
1 files changed, 0 insertions, 131 deletions
diff --git a/sysdeps/x86_64/start.S b/sysdeps/x86_64/start.S deleted file mode 100644 index 62a00eaeaa..0000000000 --- a/sysdeps/x86_64/start.S +++ /dev/null @@ -1,131 +0,0 @@ -/* Startup code compliant to the ELF x86-64 ABI. - Copyright (C) 2001-2017 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contributed by Andreas Jaeger <aj@suse.de>, 2001. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - In addition to the permissions in the GNU Lesser General Public - License, the Free Software Foundation gives you unlimited - permission to link the compiled version of this file with other - programs, and to distribute those programs without any restriction - coming from the use of this file. (The GNU Lesser General Public - License restrictions do apply in other respects; for example, they - cover modification of the file, and distribution when not linked - into another program.) - - Note that people who make modified versions of this file are not - obligated to grant this special exception for their modified - versions; it is their choice whether to do so. The GNU Lesser - General Public License gives permission to release a modified - version without this exception; this exception also makes it - possible to release a modified version which carries forward this - exception. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - <http://www.gnu.org/licenses/>. */ - -/* This is the canonical entry point, usually the first thing in the text - segment. The SVR4/i386 ABI (pages 3-31, 3-32) says that when the entry - point runs, most registers' values are unspecified, except for: - - %rdx Contains a function pointer to be registered with `atexit'. - This is how the dynamic linker arranges to have DT_FINI - functions called for shared libraries that have been loaded - before this code runs. - - %rsp The stack contains the arguments and environment: - 0(%rsp) argc - LP_SIZE(%rsp) argv[0] - ... - (LP_SIZE*argc)(%rsp) NULL - (LP_SIZE*(argc+1))(%rsp) envp[0] - ... - NULL -*/ - -#include <sysdep.h> - -ENTRY (_start) - /* Clearing frame pointer is insufficient, use CFI. */ - cfi_undefined (rip) - /* Clear the frame pointer. The ABI suggests this be done, to mark - the outermost frame obviously. */ - xorl %ebp, %ebp - - /* Extract the arguments as encoded on the stack and set up - the arguments for __libc_start_main (int (*main) (int, char **, char **), - int argc, char *argv, - void (*init) (void), void (*fini) (void), - void (*rtld_fini) (void), void *stack_end). - The arguments are passed via registers and on the stack: - main: %rdi - argc: %rsi - argv: %rdx - init: %rcx - fini: %r8 - rtld_fini: %r9 - stack_end: stack. */ - - mov %RDX_LP, %R9_LP /* Address of the shared library termination - function. */ -#ifdef __ILP32__ - mov (%rsp), %esi /* Simulate popping 4-byte argument count. */ - add $4, %esp -#else - popq %rsi /* Pop the argument count. */ -#endif - /* argv starts just at the current stack top. */ - mov %RSP_LP, %RDX_LP - /* Align the stack to a 16 byte boundary to follow the ABI. */ - and $~15, %RSP_LP - - /* Push garbage because we push 8 more bytes. */ - pushq %rax - - /* Provide the highest stack address to the user code (for stacks - which grow downwards). */ - pushq %rsp - -#ifdef SHARED - /* Pass address of our own entry points to .fini and .init. */ - mov __libc_csu_fini@GOTPCREL(%rip), %R8_LP - mov __libc_csu_init@GOTPCREL(%rip), %RCX_LP - - mov main@GOTPCREL(%rip), %RDI_LP -#else - /* Pass address of our own entry points to .fini and .init. */ - mov $__libc_csu_fini, %R8_LP - mov $__libc_csu_init, %RCX_LP - - mov $main, %RDI_LP -#endif - - /* Call the user's main function, and exit with its value. - But let the libc call main. Since __libc_start_main in - libc.so is called very early, lazy binding isn't relevant - here. Use indirect branch via GOT to avoid extra branch - to PLT slot. In case of static executable, ld in binutils - 2.26 or above can convert indirect branch into direct - branch. */ - call *__libc_start_main@GOTPCREL(%rip) - - hlt /* Crash if somehow `exit' does return. */ -END (_start) - -/* Define a symbol for the first piece of initialized data. */ - .data - .globl __data_start -__data_start: - .long 0 - .weak data_start - data_start = __data_start |