u-boot/arch/powerpc/cpu/mpc8220/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

104 lines
2.4 KiB
C

/*
* (C) Copyright 2000-2003
* Wolfgang Denk, DENX Software Engineering, wd@denx.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 for the MPC8220 CPUs
*/
#include <common.h>
#include <watchdog.h>
#include <command.h>
#include <mpc8220.h>
#include <netdev.h>
#include <asm/processor.h>
DECLARE_GLOBAL_DATA_PTR;
int checkcpu (void)
{
ulong clock = gd->cpu_clk;
char buf[32];
puts ("CPU: ");
printf (CPU_ID_STR);
printf (" (JTAG ID %08lx)", *(vu_long *) (CONFIG_SYS_MBAR + 0x50));
printf (" at %s MHz\n", strmhz (buf, clock));
return 0;
}
/* ------------------------------------------------------------------------- */
int do_reset (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
volatile gptmr8220_t *gptmr = (volatile gptmr8220_t *) MMAP_GPTMR;
ulong msr;
/* Interrupts and MMU off */
__asm__ __volatile__ ("mfmsr %0":"=r" (msr):);
msr &= ~(MSR_ME | MSR_EE | MSR_IR | MSR_DR);
__asm__ __volatile__ ("mtmsr %0"::"r" (msr));
/* Charge the watchdog timer */
gptmr->Prescl = 10;
gptmr->Count = 1;
gptmr->Mode = GPT_TMS_SGPIO;
gptmr->Control = GPT_CTRL_WDEN | GPT_CTRL_CE;
return 1;
}
/* ------------------------------------------------------------------------- */
/*
* Get timebase clock frequency (like cpu_clk in Hz)
*
*/
unsigned long get_tbclk (void)
{
ulong tbclk;
tbclk = (gd->bus_clk + 3L) / 4L;
return (tbclk);
}
/* ------------------------------------------------------------------------- */
/*
* Initializes on-chip ethernet controllers.
* to override, implement board_eth_init()
*/
int cpu_eth_init(bd_t *bis)
{
#if defined(CONFIG_MPC8220_FEC)
mpc8220_fec_initialize(bis);
#endif
return 0;
}