u-boot/common/cmd_cplbinfo.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

59 lines
1.4 KiB
C

/*
* cmd_cplbinfo.c - dump the instruction/data cplb tables
*
* Copyright (c) 2007-2008 Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*/
#include <common.h>
#include <command.h>
#include <asm/blackfin.h>
#include <asm/cplb.h>
#include <asm/mach-common/bits/mpu.h>
/*
* Translate the PAGE_SIZE bits into a human string
*/
static const char *cplb_page_size(uint32_t data)
{
static const char page_size_string_table[][4] = { "1K", "4K", "1M", "4M" };
return page_size_string_table[(data & PAGE_SIZE_MASK) >> PAGE_SIZE_SHIFT];
}
/*
* show a hardware cplb table
*/
static void show_cplb_table(uint32_t *addr, uint32_t *data)
{
int i;
printf(" Address Data Size Valid Locked\n");
for (i = 1; i <= 16; ++i) {
printf(" %2i 0x%p 0x%05X %s %c %c\n",
i, (void *)*addr, *data,
cplb_page_size(*data),
(*data & CPLB_VALID ? 'Y' : 'N'),
(*data & CPLB_LOCK ? 'Y' : 'N'));
++addr;
++data;
}
}
/*
* display current instruction and data cplb tables
*/
int do_cplbinfo(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
printf("%s CPLB table [%08x]:\n", "Instruction", *(uint32_t *)DMEM_CONTROL);
show_cplb_table((uint32_t *)ICPLB_ADDR0, (uint32_t *)ICPLB_DATA0);
printf("%s CPLB table [%08x]:\n", "Data", *(uint32_t *)IMEM_CONTROL);
show_cplb_table((uint32_t *)DCPLB_ADDR0, (uint32_t *)DCPLB_DATA0);
return 0;
}
U_BOOT_CMD(cplbinfo, 1, 0, do_cplbinfo,
"display current CPLB tables",
""
);