u-boot/arch/blackfin/cpu/reset.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

106 lines
2.7 KiB
C

/*
* reset.c - logic for resetting the cpu
*
* Copyright (c) 2005-2008 Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*/
#include <common.h>
#include <command.h>
#include <asm/blackfin.h>
#include "cpu.h"
/* A system soft reset makes external memory unusable so force
* this function into L1. We use the compiler ssync here rather
* than SSYNC() because it's safe (no interrupts and such) and
* we save some L1. We do not need to force sanity in the SYSCR
* register as the BMODE selection bit is cleared by the soft
* reset while the Core B bit (on dual core parts) is cleared by
* the core reset.
*/
__attribute__ ((__l1_text__, __noreturn__))
static void bfin_reset(void)
{
/* Wait for completion of "system" events such as cache line
* line fills so that we avoid infinite stalls later on as
* much as possible. This code is in L1, so it won't trigger
* any such event after this point in time.
*/
__builtin_bfin_ssync();
/* The bootrom checks to see how it was reset and will
* automatically perform a software reset for us when
* it starts executing after the core reset.
*/
if (ANOMALY_05000353 || ANOMALY_05000386) {
/* Initiate System software reset. */
bfin_write_SWRST(0x7);
/* Due to the way reset is handled in the hardware, we need
* to delay for 10 SCLKS. The only reliable way to do this is
* to calculate the CCLK/SCLK ratio and multiply 10. For now,
* we'll assume worse case which is a 1:15 ratio.
*/
asm(
"LSETUP (1f, 1f) LC0 = %0\n"
"1: nop;"
:
: "a" (15 * 10)
: "LC0", "LB0", "LT0"
);
/* Clear System software reset */
bfin_write_SWRST(0);
/* The BF526 ROM will crash during reset */
#if defined(__ADSPBF522__) || defined(__ADSPBF524__) || defined(__ADSPBF526__)
bfin_read_SWRST();
#endif
/* Wait for the SWRST write to complete. Cannot rely on SSYNC
* though as the System state is all reset now.
*/
asm(
"LSETUP (1f, 1f) LC1 = %0\n"
"1: nop;"
:
: "a" (15 * 1)
: "LC1", "LB1", "LT1"
);
}
while (1)
/* Issue core reset */
asm("raise 1");
}
/* We need to trampoline ourselves up into L1 since our linker
* does not have relaxtion support and will only generate a
* PC relative call with a 25 bit immediate. This is not enough
* to get us from the top of SDRAM into L1.
*/
__attribute__ ((__noreturn__))
static inline void bfin_reset_trampoline(void)
{
if (board_reset)
board_reset();
while (1)
asm("jump (%0);" : : "a" (bfin_reset));
}
__attribute__ ((__noreturn__))
void bfin_reset_or_hang(void)
{
#ifdef CONFIG_PANIC_HANG
hang();
#else
bfin_reset_trampoline();
#endif
}
int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
bfin_reset_trampoline();
return 0;
}