/* Copyright (C) 1995-2020 Free Software Foundation, Inc. This file is part of the GNU C Library. 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. 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 . */ #include /* This is the canonical entry point, usually the first thing in the text segment. Note that the code in the .init section has already been run. This includes _init and _libc_init At this entry point, most registers' values are unspecified, except: x0/w0 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. sp The stack contains the arguments and environment: 0(sp) argc 8(sp) argv[0] ... (8*argc)(sp) NULL (8*(argc+1))(sp) envp[0] ... NULL */ .text .globl _start .type _start,#function _start: /* Create an initial frame with 0 LR and FP */ mov x29, #0 mov x30, #0 /* Setup rtld_fini in argument register */ mov x5, x0 /* Load argc and a pointer to argv */ ldr PTR_REG (1), [sp, #0] add x2, sp, #PTR_SIZE /* Setup stack limit in argument register */ mov x6, sp #ifdef PIC # ifdef SHARED adrp x0, :got:main ldr PTR_REG (0), [x0, #:got_lo12:main] adrp x3, :got:__libc_csu_init ldr PTR_REG (3), [x3, #:got_lo12:__libc_csu_init] adrp x4, :got:__libc_csu_fini ldr PTR_REG (4), [x4, #:got_lo12:__libc_csu_fini] # else adrp x0, __wrap_main add x0, x0, :lo12:__wrap_main adrp x3, __libc_csu_init add x3, x3, :lo12:__libc_csu_init adrp x4, __libc_csu_fini add x4, x4, :lo12:__libc_csu_fini # endif #else /* Set up the other arguments in registers */ MOVL (0, main) MOVL (3, __libc_csu_init) MOVL (4, __libc_csu_fini) #endif /* __libc_start_main (main, argc, argv, init, fini, rtld_fini, stack_end) */ /* Let the libc call main and exit with its return code. */ bl __libc_start_main /* should never get here....*/ bl abort #if defined PIC && !defined SHARED /* When main is not defined in the executable but in a shared library then a wrapper is needed in crt1.o of the static-pie enabled libc, because crt1.o and rcrt1.o share code and the later must avoid the use of GOT relocations before __libc_start_main is called. */ __wrap_main: b main #endif /* 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