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u-boot/arch/powerpc/cpu/mpc8260/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

279 lines
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/*
* (C) Copyright 2000-2002
* 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
*
* Hacked for MPC8260 by Murray.Jensen@cmst.csiro.au, 22-Oct-00
*/
#include <common.h>
#include <command.h>
#include <mpc8260.h>
#include <mpc8260_irq.h>
#include <asm/processor.h>
DECLARE_GLOBAL_DATA_PTR;
/****************************************************************************/
struct irq_action {
interrupt_handler_t *handler;
void *arg;
ulong count;
};
static struct irq_action irq_handlers[NR_IRQS];
static ulong ppc_cached_irq_mask[NR_MASK_WORDS];
/****************************************************************************/
/* this section was ripped out of arch/powerpc/kernel/ppc8260_pic.c in the */
/* Linux/PPC 2.4.x source. There was no copyright notice in that file. */
/* The 8260 internal interrupt controller. It is usually
* the only interrupt controller.
* There are two 32-bit registers (high/low) for up to 64
* possible interrupts.
*
* Now, the fun starts.....Interrupt Numbers DO NOT MAP
* in a simple arithmetic fashion to mask or pending registers.
* That is, interrupt 4 does not map to bit position 4.
* We create two tables, indexed by vector number, to indicate
* which register to use and which bit in the register to use.
*/
static u_char irq_to_siureg[] = {
1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0
};
static u_char irq_to_siubit[] = {
31, 16, 17, 18, 19, 20, 21, 22,
23, 24, 25, 26, 27, 28, 29, 30,
29, 30, 16, 17, 18, 19, 20, 21,
22, 23, 24, 25, 26, 27, 28, 31,
0, 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15,
15, 14, 13, 12, 11, 10, 9, 8,
7, 6, 5, 4, 3, 2, 1, 0
};
static void m8260_mask_irq (unsigned int irq_nr)
{
volatile immap_t *immr = (immap_t *) CONFIG_SYS_IMMR;
int bit, word;
volatile uint *simr;
bit = irq_to_siubit[irq_nr];
word = irq_to_siureg[irq_nr];
simr = &(immr->im_intctl.ic_simrh);
ppc_cached_irq_mask[word] &= ~(1 << (31 - bit));
simr[word] = ppc_cached_irq_mask[word];
}
static void m8260_unmask_irq (unsigned int irq_nr)
{
volatile immap_t *immr = (immap_t *) CONFIG_SYS_IMMR;
int bit, word;
volatile uint *simr;
bit = irq_to_siubit[irq_nr];
word = irq_to_siureg[irq_nr];
simr = &(immr->im_intctl.ic_simrh);
ppc_cached_irq_mask[word] |= (1 << (31 - bit));
simr[word] = ppc_cached_irq_mask[word];
}
static void m8260_mask_and_ack (unsigned int irq_nr)
{
volatile immap_t *immr = (immap_t *) CONFIG_SYS_IMMR;
int bit, word;
volatile uint *simr, *sipnr;
bit = irq_to_siubit[irq_nr];
word = irq_to_siureg[irq_nr];
simr = &(immr->im_intctl.ic_simrh);
sipnr = &(immr->im_intctl.ic_sipnrh);
ppc_cached_irq_mask[word] &= ~(1 << (31 - bit));
simr[word] = ppc_cached_irq_mask[word];
sipnr[word] = 1 << (31 - bit);
}
static int m8260_get_irq (struct pt_regs *regs)
{
volatile immap_t *immr = (immap_t *) CONFIG_SYS_IMMR;
int irq;
unsigned long bits;
/* For MPC8260, read the SIVEC register and shift the bits down
* to get the irq number. */
bits = immr->im_intctl.ic_sivec;
irq = bits >> 26;
return irq;
}
/* end of code ripped out of arch/powerpc/kernel/ppc8260_pic.c */
/****************************************************************************/
int interrupt_init_cpu (unsigned *decrementer_count)
{
volatile immap_t *immr = (immap_t *) CONFIG_SYS_IMMR;
*decrementer_count = (gd->bus_clk / 4) / CONFIG_SYS_HZ;
/* Initialize the default interrupt mapping priorities */
immr->im_intctl.ic_sicr = 0;
immr->im_intctl.ic_siprr = 0x05309770;
immr->im_intctl.ic_scprrh = 0x05309770;
immr->im_intctl.ic_scprrl = 0x05309770;
/* disable all interrupts and clear all pending bits */
immr->im_intctl.ic_simrh = ppc_cached_irq_mask[0] = 0;
immr->im_intctl.ic_simrl = ppc_cached_irq_mask[1] = 0;
immr->im_intctl.ic_sipnrh = 0xffffffff;
immr->im_intctl.ic_sipnrl = 0xffffffff;
#ifdef CONFIG_HYMOD
/*
* ensure all external interrupt sources default to trigger on
* high-to-low transition (i.e. edge triggered active low)
*/
immr->im_intctl.ic_siexr = -1;
#endif
return (0);
}
/****************************************************************************/
/*
* Handle external interrupts
*/
void external_interrupt (struct pt_regs *regs)
{
int irq, unmask = 1;
irq = m8260_get_irq (regs);
m8260_mask_and_ack (irq);
enable_interrupts ();
if (irq_handlers[irq].handler != NULL)
(*irq_handlers[irq].handler) (irq_handlers[irq].arg);
else {
printf ("\nBogus External Interrupt IRQ %d\n", irq);
/*
* turn off the bogus interrupt, otherwise it
* might repeat forever
*/
unmask = 0;
}
if (unmask)
m8260_unmask_irq (irq);
}
/****************************************************************************/
/*
* Install and free an interrupt handler.
*/
void
irq_install_handler (int irq, interrupt_handler_t * handler, void *arg)
{
if (irq < 0 || irq >= NR_IRQS) {
printf ("irq_install_handler: bad irq number %d\n", irq);
return;
}
if (irq_handlers[irq].handler != NULL)
printf ("irq_install_handler: 0x%08lx replacing 0x%08lx\n",
(ulong) handler, (ulong) irq_handlers[irq].handler);
irq_handlers[irq].handler = handler;
irq_handlers[irq].arg = arg;
m8260_unmask_irq (irq);
}
void irq_free_handler (int irq)
{
if (irq < 0 || irq >= NR_IRQS) {
printf ("irq_free_handler: bad irq number %d\n", irq);
return;
}
m8260_mask_irq (irq);
irq_handlers[irq].handler = NULL;
irq_handlers[irq].arg = NULL;
}
/****************************************************************************/
void timer_interrupt_cpu (struct pt_regs *regs)
{
/* nothing to do here */
return;
}
/****************************************************************************/
#if defined(CONFIG_CMD_IRQ)
/* ripped this out of ppc4xx/interrupts.c */
/*******************************************************************************
*
* irqinfo - print information about PCI devices
*
*/
void
do_irqinfo (cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char * const argv[])
{
int irq, re_enable;
re_enable = disable_interrupts ();
puts ("\nInterrupt-Information:\n"
"Nr Routine Arg Count\n");
for (irq = 0; irq < 32; irq++)
if (irq_handlers[irq].handler != NULL)
printf ("%02d %08lx %08lx %ld\n", irq,
(ulong) irq_handlers[irq].handler,
(ulong) irq_handlers[irq].arg,
irq_handlers[irq].count);
if (re_enable)
enable_interrupts ();
}
#endif
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