u-boot/arch/powerpc/cpu/74xx_7xx/interrupts.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
2.8 KiB
C

/*
* (C) Copyright 2001
* Josh Huber <huber@mclx.com>, Mission Critical Linux, Inc.
*
* 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
*/
/*
* interrupts.c - just enough support for the decrementer/timer
*/
#include <common.h>
#include <mpc8xx.h>
#include <mpc8xx_irq.h>
#include <asm/processor.h>
#include <commproc.h>
#include <command.h>
int interrupt_init_cpu (unsigned *decrementer_count)
{
debug("interrupt_init: GT main cause reg: %08x:%08x\n",
GTREGREAD(LOW_INTERRUPT_CAUSE_REGISTER),
GTREGREAD(HIGH_INTERRUPT_CAUSE_REGISTER));
debug("interrupt_init: ethernet cause regs: %08x %08x %08x\n",
GTREGREAD(ETHERNET0_INTERRUPT_CAUSE_REGISTER),
GTREGREAD(ETHERNET1_INTERRUPT_CAUSE_REGISTER),
GTREGREAD(ETHERNET2_INTERRUPT_CAUSE_REGISTER));
debug("interrupt_init: ethernet mask regs: %08x %08x %08x\n",
GTREGREAD(ETHERNET0_INTERRUPT_MASK_REGISTER),
GTREGREAD(ETHERNET1_INTERRUPT_MASK_REGISTER),
GTREGREAD(ETHERNET2_INTERRUPT_MASK_REGISTER));
debug("interrupt_init: setting decrementer_count\n");
*decrementer_count = get_tbclk() / CONFIG_SYS_HZ;
return (0);
}
/****************************************************************************/
/*
* Handle external interrupts
*/
void
external_interrupt(struct pt_regs *regs)
{
puts("external_interrupt (oops!)\n");
}
volatile ulong timestamp = 0;
/*
* timer_interrupt - gets called when the decrementer overflows,
* with interrupts disabled.
* Trivial implementation - no need to be really accurate.
*/
void
timer_interrupt_cpu (struct pt_regs *regs)
{
/* nothing to do here */
return;
}
/****************************************************************************/
/*
* Install and free a interrupt handler.
*/
void
irq_install_handler(int vec, interrupt_handler_t *handler, void *arg)
{
}
void
irq_free_handler(int vec)
{
}
/****************************************************************************/
void
do_irqinfo(cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char * const argv[])
{
puts("IRQ related functions are unimplemented currently.\n");
}