u-boot/arch/i386/cpu/cpu.c
Wolfgang Denk 54841ab50c Make sure that argv[] argument pointers are not modified.
The hush shell dynamically allocates (and re-allocates) memory for the
argument strings in the "char *argv[]" argument vector passed to
commands.  Any code that modifies these pointers will cause serious
corruption of the malloc data structures and crash U-Boot, so make
sure the compiler can check that no such modifications are being done
by changing the code into "char * const argv[]".

This modification is the result of debugging a strange crash caused
after adding a new command, which used the following argument
processing code which has been working perfectly fine in all Unix
systems since version 6 - but not so in U-Boot:

int main (int argc, char **argv)
{
	while (--argc > 0 && **++argv == '-') {
/* ====> */	while (*++*argv) {
			switch (**argv) {
			case 'd':
				debug++;
				break;
			...
			default:
				usage ();
			}
		}
	}
	...
}

The line marked "====>" will corrupt the malloc data structures and
usually cause U-Boot to crash when the next command gets executed by
the shell.  With the modification, the compiler will prevent this with
an
	error: increment of read-only location '*argv'

N.B.: The code above can be trivially rewritten like this:

	while (--argc > 0 && **++argv == '-') {
		char *arg = *argv;
		while (*++arg) {
			switch (*arg) {
			...

Signed-off-by: Wolfgang Denk <wd@denx.de>
Acked-by: Mike Frysinger <vapier@gentoo.org>
2010-07-04 23:55:42 +02:00

92 lines
2.4 KiB
C

/*
* (C) Copyright 2002
* Daniel Engström, Omicron Ceti AB, daniel@omicron.se.
*
* (C) Copyright 2002
* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
* Marius Groeger <mgroeger@sysgo.de>
*
* (C) Copyright 2002
* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
* Alex Zuepke <azu@sysgo.de>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
/*
* CPU specific code
*/
#include <common.h>
#include <command.h>
#include <asm/interrupt.h>
int cpu_init_f(void)
{
/* initialize FPU, reset EM, set MP and NE */
asm ("fninit\n" \
"movl %cr0, %eax\n" \
"andl $~0x4, %eax\n" \
"orl $0x22, %eax\n" \
"movl %eax, %cr0\n" );
return 0;
}
int cpu_init_r(void)
{
/* Initialize core interrupt and exception functionality of CPU */
cpu_init_interrupts ();
return 0;
}
int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
printf ("resetting ...\n");
udelay(50000); /* wait 50 ms */
disable_interrupts();
reset_cpu(0);
/*NOTREACHED*/
return 0;
}
void flush_cache (unsigned long dummy1, unsigned long dummy2)
{
asm("wbinvd\n");
return;
}
void __attribute__ ((regparm(0))) generate_gpf(void);
/* segment 0x70 is an arbitrary segment which does not exist */
asm(".globl generate_gpf\n"
".hidden generate_gpf\n"
".type generate_gpf, @function\n"
"generate_gpf:\n"
"ljmp $0x70, $0x47114711\n");
void __reset_cpu(ulong addr)
{
printf("Resetting using i386 Triple Fault\n");
set_vector(13, generate_gpf); /* general protection fault handler */
set_vector(8, generate_gpf); /* double fault handler */
generate_gpf(); /* start the show */
}
void reset_cpu(ulong addr) __attribute__((weak, alias("__reset_cpu")));