104 lines
2.8 KiB
ArmAsm
104 lines
2.8 KiB
ArmAsm
/* Copyright (C) 1995-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<https://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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/* This is the canonical entry point, usually the first thing in the text
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segment.
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Note that the code in the .init section has already been run.
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This includes _init and _libc_init
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At this entry point, most registers' values are unspecified, except:
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x0/w0 Contains a function pointer to be registered with `atexit'.
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This is how the dynamic linker arranges to have DT_FINI
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functions called for shared libraries that have been loaded
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before this code runs.
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sp The stack contains the arguments and environment:
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0(sp) argc
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8(sp) argv[0]
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...
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(8*argc)(sp) NULL
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(8*(argc+1))(sp) envp[0]
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...
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NULL
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*/
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.text
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ENTRY(_start)
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/* Create an initial frame with 0 LR and FP */
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cfi_undefined (x30)
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mov x29, #0
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mov x30, #0
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/* Setup rtld_fini in argument register */
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mov x5, x0
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/* Load argc and a pointer to argv */
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ldr PTR_REG (1), [sp, #0]
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add x2, sp, #PTR_SIZE
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/* Setup stack limit in argument register */
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mov x6, sp
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#ifdef PIC
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# ifdef SHARED
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adrp x0, :got:main
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ldr PTR_REG (0), [x0, #:got_lo12:main]
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# else
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adrp x0, __wrap_main
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add x0, x0, :lo12:__wrap_main
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# endif
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#else
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/* Set up the other arguments in registers */
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MOVL (0, main)
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#endif
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mov x3, #0 /* Used to be init. */
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mov x4, #0 /* Used to be fini. */
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/* __libc_start_main (main, argc, argv, init, fini, rtld_fini,
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stack_end) */
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/* Let the libc call main and exit with its return code. */
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bl __libc_start_main
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/* should never get here....*/
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bl abort
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#if defined PIC && !defined SHARED
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/* When main is not defined in the executable but in a shared library
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then a wrapper is needed in crt1.o of the static-pie enabled libc,
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because crt1.o and rcrt1.o share code and the later must avoid the
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use of GOT relocations before __libc_start_main is called. */
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__wrap_main:
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BTI_C
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b main
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#endif
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END(_start)
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/* Define a symbol for the first piece of initialized data. */
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.data
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.globl __data_start
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__data_start:
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.long 0
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.weak data_start
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data_start = __data_start
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