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authorWaldemar Brodkorb <wbx@openadk.org>2016-05-28 18:12:58 +0200
committerWaldemar Brodkorb <wbx@uclibc-ng.org>2016-11-04 00:03:07 +0100
commitb8fcdddcbb192fc367ff04bbd753b9deb69b09f3 (patch)
tree8febdb9d4e3d090e9273c29df9ff06116196c8e4 /libc/sysdeps/linux/nios2/crt1.S
parent191739597c6d380692885cfdd8dd8aa4f31f029d (diff)
nios2: sync support with glibc
Only static linking is supported for now. More debugging and analyzing for ld.so, TLS and NPTL is required. But at least you can bootup a static root fileystem in Qemu.
Diffstat (limited to 'libc/sysdeps/linux/nios2/crt1.S')
-rw-r--r--libc/sysdeps/linux/nios2/crt1.S147
1 files changed, 93 insertions, 54 deletions
diff --git a/libc/sysdeps/linux/nios2/crt1.S b/libc/sysdeps/linux/nios2/crt1.S
index c178452ae..e13d59599 100644
--- a/libc/sysdeps/linux/nios2/crt1.S
+++ b/libc/sysdeps/linux/nios2/crt1.S
@@ -1,20 +1,40 @@
-/*
- * libc/sysdeps/linux/nios2/crt0.S -- entry point for linux/nios2
- *
- * Copyright (C) 2004,05,06 Microtronix Datacom Ltd
- *
- * This file is subject to the terms and conditions of the GNU Lesser
- * General Public License. See the file COPYING.LIB in the main
- * directory of this archive for more details.
- *
- * Written by Wentao Xu <wentao@microtronix.com>
- * Updated by Thomas Chou <thomas@wytron.com.tw> for crt1.S
- *
- */
+/* Startup code for Nios II
+ Copyright (C) 1995-2016 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.
+
+ 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/>. */
#include <features.h>
#include <asm/unistd.h>
-#define TRAP_ID_SYSCALL 0
.global _start
.type _start,@function
@@ -27,45 +47,64 @@
.type main,@function
.type __uClibc_main,@function
.text
- .balign 4
+
_start:
- nop
- br 0f
-0:
- /* load gp */
- movhi gp, %hiadj(_gp)
- addi gp, gp, %lo(_gp)
-
- /* load main, argc, argv from stack */
- movhi r4, %hi(main)
- ori r4, r4, %lo(main) /* main */
- ldw r5, 0(sp) /* argc */
- ldw r6, 4(sp) /* argv */
-
- /* load the 4th arg */
- movhi r7, %hi(_init)
- ori r7, r7, %lo(_init)
-
- /* Allocate space on the stack for 6-7th arg, reuse 5th space */
- addi sp,sp,-8
- /* push 5-7th args on stack */
- movhi r8, %hi(_fini)
- ori r8, r8, %lo(_fini)
- stw r8, 0(sp)
-
- stw r2, 4(sp) /* rtld_fini */
- stw sp, 8(sp) /* stack_end */
-
- /* call uClibc_main, shouldn't return */
-#ifdef __PIC__
- /* just pray 16 bit offset is enough */
- br __uClibc_main
-#else
- call __uClibc_main
-#endif
+ /* Set up the global pointer. */
+ movhi gp, %hiadj(_gp)
+ addi gp, gp, %lo(_gp)
+
+ /* Save the stack pointer. */
+ mov r2, sp
+
+ /* Create room on the stack for the fini, rtld_fini and stack_end args
+ to __uClibc_main. */
+ subi sp, sp, 12
+
+ /* Push stack_end */
+ stw r2, 8(sp)
+
+ /* Push rtld_fini */
+ stw r4, 4(sp)
+
+ /* Set up the GOT pointer. */
+ nextpc r22
+1: movhi r2, %hiadj(_gp_got - 1b)
+ addi r2, r2, %lo(_gp_got - 1b)
+ add r22, r22, r2
+
+ /* r6 == argv */
+ addi r6, sp, 16
+
+ /* r5 == argc */
+ ldw r5, 12(sp)
+
+ /* r4 == main */
+ movhi r4, %call_hiadj(main)
+ addi r4, r4, %call_lo(main)
+ add r4, r4, r22
+ ldw r4, 0(r4)
+
+ /* fp == 0 */
+ mov fp, zero
+
+ /* Let the libc call main and exit with its return code. */
+ movhi r2, %call_hiadj(__uClibc_main)
+ addi r2, r2, %call_lo(__uClibc_main)
+ add r2, r2, r22
+ ldw r2, 0(r2)
+ callr r2
+
+ /* should never get here....*/
+ movhi r2, %call_hiadj(abort)
+ addi r2, r2, %call_lo(abort)
+ add r2, r2, r22
+ ldw r2, 0(r2)
+ callr r2
- /* crash in the event of return */
-__exit:
- movui r2, TRAP_ID_SYSCALL
- movui r3, __NR_exit
- trap
+/* 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