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de5c0edc80
Code for C runtime startup and dynamic loading including PLT layout. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
99 lines
2.4 KiB
ArmAsm
99 lines
2.4 KiB
ArmAsm
/* Machine-dependent ELF startup code. 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, see
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<https://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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/* Initial entry point code for the dynamic linker.
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The function _dl_start is the real entry point;
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it's return value is the user program's entry point. */
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ENTRY (_start)
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/* Count arguments in r11 */
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l.ori r3, r1, 0
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l.movhi r11, 0
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1:
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l.addi r3, r3, 4
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l.lwz r12, 0(r3)
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l.sfnei r12, 0
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l.addi r11, r11, 1
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l.bf 1b
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l.nop
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l.addi r11, r11, -1
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/* store argument counter to stack. */
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l.sw 0(r1), r11
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/* Load the PIC register. */
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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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l.ori r3, r1, 0
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l.jal _dl_start
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l.nop
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/* Save user entry in a call saved reg. */
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l.ori r22, r11, 0
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/* Fall through to _dl_start_user. */
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_dl_start_user:
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/* Set up for _dl_init. */
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/* Load _rtld_local (a.k.a _dl_loaded). */
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l.lwz r12, got(_rtld_local)(r16)
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l.lwz r3, 0(r12)
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/* Load argc */
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l.lwz r18, got(_dl_argc)(r16)
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l.lwz r4, 0(r18)
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/* Load argv */
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l.lwz r20, got(_dl_argv)(r16)
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l.lwz r5, 0(r20)
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/* Load envp = &argv[argc + 1]. */
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l.slli r6, r4, 2
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l.addi r6, r6, 4
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l.add r6, r6, r5
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l.jal plt(_dl_init)
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l.nop
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/* Now set up for user entry.
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The already defined ABI loads argc and argv from the stack.
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argc = 0(r1)
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argv = r1 + 4
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*/
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/* Load SP as argv - 4. */
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l.lwz r3, 0(r20)
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l.addi r1, r3, -4
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/* Save argc. */
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l.lwz r3, 0(r18)
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l.sw 0(r1), r3
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/* Pass _dl_fini function address to _start.
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Next start.S will then pass this as rtld_fini to __libc_start_main. */
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l.lwz r3, got(_dl_fini)(r16)
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l.jr r22
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l.nop
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END (_start)
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