mirror of
https://github.com/AsahiLinux/u-boot
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54841ab50c
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>
136 lines
3.5 KiB
C
136 lines
3.5 KiB
C
/**
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* Copyright 2010 Freescale Semiconductor
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* Author: Timur Tabi <timur@freescale.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* This file provides support for the ngPIXIS, a board-specific FPGA used on
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* some Freescale reference boards.
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*
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* A "switch" is black rectangular block on the motherboard. It contains
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* eight "bits". The ngPIXIS has a set of memory-mapped registers (SWx) that
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* shadow the actual physical switches. There is also another set of
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* registers (ENx) that tell the ngPIXIS which bits of SWx should actually be
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* used to override the values of the bits in the physical switches.
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*
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* The following macros need to be defined:
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*
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* PIXIS_BASE - The virtual address of the base of the PIXIS register map
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*
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* PIXIS_LBMAP_SWITCH - The switch number (i.e. the "x" in "SWx"). This value
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* is used in the PIXIS_SW() macro to determine which offset in
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* the PIXIS register map corresponds to the physical switch that controls
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* the boot bank.
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*
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* PIXIS_LBMAP_MASK - A bit mask the defines which bits in SWx to use.
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*
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* PIXIS_LBMAP_SHIFT - The shift value that corresponds to PIXIS_LBMAP_MASK.
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*
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* PIXIS_LBMAP_ALTBANK - The value to program into SWx to tell the ngPIXIS to
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* boot from the alternate bank.
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*/
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#include <common.h>
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#include <command.h>
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#include <watchdog.h>
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#include <asm/cache.h>
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#include <asm/io.h>
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#include "ngpixis.h"
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/*
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* Reset the board. This ignores the ENx registers.
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*/
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void pixis_reset(void)
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{
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out_8(&pixis->rst, 0);
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while (1);
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}
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/*
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* Reset the board. Like pixis_reset(), but it honors the ENx registers.
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*/
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void pixis_bank_reset(void)
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{
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out_8(&pixis->vctl, 0);
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out_8(&pixis->vctl, 1);
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while (1);
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}
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/**
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* Set the boot bank to the power-on default bank
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*/
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void clear_altbank(void)
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{
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/* Tell the ngPIXIS to use this the bits in the physical switch for the
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* boot bank value, instead of the SWx register. We need to be careful
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* only to set the bits in SWx that correspond to the boot bank.
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*/
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clrbits_8(&PIXIS_EN(PIXIS_LBMAP_SWITCH), PIXIS_LBMAP_MASK);
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}
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/**
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* Set the boot bank to the alternate bank
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*/
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void set_altbank(void)
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{
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/* Program the alternate bank number into the SWx register.
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*/
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clrsetbits_8(&PIXIS_SW(PIXIS_LBMAP_SWITCH), PIXIS_LBMAP_MASK,
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PIXIS_LBMAP_ALTBANK);
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/* Tell the ngPIXIS to use this the bits in the SWx register for the
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* boot bank value, instead of the physical switch. We need to be
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* careful only to set the bits in SWx that correspond to the boot bank.
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*/
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setbits_8(&PIXIS_EN(PIXIS_LBMAP_SWITCH), PIXIS_LBMAP_MASK);
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}
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int pixis_reset_cmd(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
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{
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unsigned int i;
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char *p_altbank = NULL;
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char *unknown_param = NULL;
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/* No args is a simple reset request.
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*/
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if (argc <= 1)
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pixis_reset();
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for (i = 1; i < argc; i++) {
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if (strcmp(argv[i], "altbank") == 0) {
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p_altbank = argv[i];
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continue;
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}
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unknown_param = argv[i];
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}
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if (unknown_param) {
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printf("Invalid option: %s\n", unknown_param);
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return 1;
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}
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if (p_altbank)
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set_altbank();
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else
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clear_altbank();
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pixis_bank_reset();
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/* Shouldn't be reached. */
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return 0;
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}
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U_BOOT_CMD(
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pixis_reset, CONFIG_SYS_MAXARGS, 1, pixis_reset_cmd,
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"Reset the board using the FPGA sequencer",
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"- hard reset to default bank\n"
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"pixis_reset altbank - reset to alternate bank\n"
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);
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