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This commit is contained in:
Roland McGrath
184
sysdeps/unix/sparc/start.c
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184
sysdeps/unix/sparc/start.c
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/* Copyright (C) 1991, 1992, 1993, 1994, 1995 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 Library General Public License as
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published by the Free Software Foundation; either version 2 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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <ansidecl.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#ifndef NO_SHLIB
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#include <sys/exec.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <link.h>
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#include <syscall.h>
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#endif
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#if !defined (__GNUC__) || __GNUC__ < 2
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#error This file uses GNU C extensions; you must compile with GCC version 2.
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#endif
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/* The first piece of initialized data. */
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int __data_start = 0;
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#ifdef HAVE_WEAK_SYMBOLS
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weak_alias (__data_start, data_start)
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#endif
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VOLATILE int errno;
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#ifdef HAVE_WEAK_SYMBOLS
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weak_alias (__environ, environ)
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#else
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#undef environ
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#define __environ environ
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#endif
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char **__environ;
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extern void EXFUN(__libc_init, (int argc, char **argv, char **envp));
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extern int EXFUN(main, (int argc, char **argv, char **envp));
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register long int sp asm("%sp"), fp asm("%fp");
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#ifndef NO_SHLIB
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static void EXFUN(init_shlib, (NOARGS));
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#endif
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#ifndef NO_EXPLICIT_START
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/* Declare _start with an explicit assembly symbol name of `start'
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(note no leading underscore). This is the name Sun's crt0.o uses,
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and programs are often linked with `ld -e start'. */
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void _start (void) asm ("start");
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#endif
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void
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_start (void)
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{
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/* It is important that these be declared `register'.
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Otherwise, when compiled without optimization, they are put on the
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stack, which loses completely after we zero the FP. */
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register int argc;
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register char **argv, **envp;
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/* Unwind the frame built when we entered the function. */
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asm("restore");
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/* And clear the frame pointer. */
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fp = 0;
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/* The argument info starts after one register
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window (64 bytes) past the SP. */
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argc = ((int *) sp)[16];
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argv = (char **) &((int *) sp)[17];
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envp = &argv[argc + 1];
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__environ = envp;
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#ifndef NO_SHLIB
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init_shlib ();
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#endif
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/* Allocate 24 bytes of stack space for the register save area. */
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sp -= 24;
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__libc_init (argc, argv, envp);
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exit (main (argc, argv, envp));
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}
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#ifndef NO_SHLIB
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/* System calls for use by the bootstrap routine.
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These are defined here since the usual calls may be dynamically linked. */
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int syscall (int sysno, ...) asm ("init_syscall");
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asm ("init_syscall:\n"
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" clr %g1\n"
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" ta 0\n"
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" bcc 1f\n"
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" sethi %hi(_errno), %g1\n"
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" st %o0, [%g1 + %lo(_errno)]\n"
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" sub %g0, 1, %o0\n"
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"1:retl\n"
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" nop");
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static void
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DEFUN_VOID(init_shlib)
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{
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extern struct link_dynamic _DYNAMIC;
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int so, zf;
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caddr_t somap;
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caddr_t sodmap;
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caddr_t sobssmap;
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void (*ldstart) (int, int);
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struct exec soexec;
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struct
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{
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caddr_t crt_ba;
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int crt_dzfd;
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int crt_ldfd;
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struct link_dynamic *crt_dp;
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char **crt_ep;
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caddr_t crt_bp;
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} soarg;
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/* If not dynamically linked, do nothing. */
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if (&_DYNAMIC == 0)
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return;
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/* Map in the dynamic linker. */
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so = syscall (SYS_open, "/usr/lib/ld.so", O_RDONLY);
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if (syscall (SYS_read, so, &soexec, sizeof (soexec)) != sizeof (soexec)
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|| soexec.a_magic != ZMAGIC)
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{
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static CONST char emsg[] = "crt0: no /usr/lib/ld.so\n";
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syscall (SYS_write, 2, emsg, sizeof (emsg) - 1);
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syscall (SYS_exit, 127);
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}
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somap = (caddr_t) syscall (SYS_mmap, 0,
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soexec.a_text + soexec.a_data + soexec.a_bss,
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PROT_READ | PROT_EXEC, _MAP_NEW | MAP_PRIVATE,
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so, 0);
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sodmap = (caddr_t) syscall (SYS_mmap, somap + soexec.a_text, soexec.a_data,
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PROT_READ | PROT_WRITE | PROT_EXEC,
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_MAP_NEW | MAP_FIXED | MAP_PRIVATE,
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so, soexec.a_text);
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zf = syscall (SYS_open, "/dev/zero", O_RDONLY);
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if (soexec.a_bss != 0)
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sobssmap = (caddr_t) syscall (SYS_mmap,
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somap + soexec.a_text + soexec.a_data,
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soexec.a_bss,
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PROT_READ | PROT_WRITE | PROT_EXEC,
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_MAP_NEW | MAP_FIXED | MAP_PRIVATE,
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zf, 0);
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/* Call the entry point of the dynamic linker. */
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soarg.crt_ba = somap;
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soarg.crt_dzfd = zf;
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soarg.crt_ldfd = so;
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soarg.crt_dp = &_DYNAMIC;
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soarg.crt_ep = __environ;
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soarg.crt_bp = (caddr_t) &&retaddr;
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ldstart = (__typeof (ldstart)) (somap + soexec.a_entry);
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(*ldstart) (1, (char *) &soarg - (char *) sp);
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retaddr:
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}
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#endif
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