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de5c0edc80
Code for C runtime startup and dynamic loading including PLT layout. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
100 lines
2.7 KiB
ArmAsm
100 lines
2.7 KiB
ArmAsm
/* start, OpenRISC version.
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Copyright (C) 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
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License as published by the Free Software Foundation; either
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version 2.1 of the 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, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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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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sp The stack contains the arguments and environment:
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0(sp) argc
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4(sp) argv[0]
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...
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(4*argc)(sp) NULL
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(4*(argc+1))(sp) envp[0]
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...
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NULL
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*/
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#define __ASSEMBLY__
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#include <sysdep.h>
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#include <entry.h>
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ENTRY (ENTRY_POINT)
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/* Setup Arguments to the __libc_start_main function. */
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/* Take values for argc and argv off the stack.
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These will be passed as arguments two and three to main
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and thus go in registers r4 and r5, respectively. */
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l.lwz r4, 0(r1)
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l.addi r5, r1, 4
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/* Pass in rtld_fini from dl-start.S. */
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l.or r8, r3, r3
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#ifdef PIC
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/* Obtain a pointer to .got in r16 */
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l.jal 0x8
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l.movhi r16, gotpchi(_GLOBAL_OFFSET_TABLE_-4)
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l.ori r16, r16, gotpclo(_GLOBAL_OFFSET_TABLE_+0)
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l.add r16, r16, r9
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/* Pass in the the main symbol. */
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l.lwz r3, got(main)(r16)
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#else
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/* Pass in the the main symbol. */
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l.movhi r3, hi(main)
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l.ori r3, r3, lo(main)
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#endif
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/* Used to be init and fini. */
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l.movhi r6, 0x0
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l.movhi r7, 0x0
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/* Push stack limit onto the stack.
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This provides the highest stack address to user code (as stack grows
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downwards.
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This is the seventh argument to __libc_start_main and thus needs to
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be passed on the stack. */
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l.sw -4(r1), r1
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/* Adjust stack to account for a total of 7 args (i.e. the last one is
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on the stack. */
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l.addi r1, r1, -4
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/* Clear the frame pointer and link register since this is the
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outermost frame. */
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l.movhi r2, 0x0
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l.movhi r9, 0x0
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/* Let the libc call main and exit with its return code. */
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#ifdef PIC
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l.j plt(__libc_start_main)
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#else
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l.j __libc_start_main
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#endif
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l.nop
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END (ENTRY_POINT)
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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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