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