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>

3 files changed, 3 insertions, 3 deletions

diff --git a/arch/powerpc/cpu/mpc85xx/cpu.c b/arch/powerpc/cpu/mpc85xx/cpu.c
index fddeb2fb09..6f81fdf61b 100644
--- a/arch/powerpc/cpu/mpc85xx/cpu.c
+++ b/arch/powerpc/cpu/mpc85xx/cpu.c
@@ -186,7 +186,7 @@ int checkcpu (void)
 
 /* ------------------------------------------------------------------------- */
 
-int do_reset (cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char *argv[])
+int do_reset (cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char * const argv[])
 {
 /* Everything after the first generation of PQ3 parts has RSTCR */
 #if defined(CONFIG_MPC8540) || defined(CONFIG_MPC8541) || \
diff --git a/arch/powerpc/cpu/mpc85xx/interrupts.c b/arch/powerpc/cpu/mpc85xx/interrupts.c
index 409367d158..ac8c01ac15 100644
--- a/arch/powerpc/cpu/mpc85xx/interrupts.c
+++ b/arch/powerpc/cpu/mpc85xx/interrupts.c
@@ -103,7 +103,7 @@ void timer_interrupt_cpu(struct pt_regs *regs)
 
 #if defined(CONFIG_CMD_IRQ)
 /* irqinfo - print information about PCI devices,not implemented. */
-int do_irqinfo(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_irqinfo(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	return 0;
 }
diff --git a/arch/powerpc/cpu/mpc85xx/mp.c b/arch/powerpc/cpu/mpc85xx/mp.c
index 826bf32d4d..ddbc2211c3 100644
--- a/arch/powerpc/cpu/mpc85xx/mp.c
+++ b/arch/powerpc/cpu/mpc85xx/mp.c
@@ -105,7 +105,7 @@ static u8 boot_entry_map[4] = {
 	BOOT_ENTRY_R6_LOWER,
 };
 
-int cpu_release(int nr, int argc, char *argv[])
+int cpu_release(int nr, int argc, char * const argv[])
 {
 	u32 i, val, *table = (u32 *)get_spin_virt_addr() + nr * NUM_BOOT_ENTRY;
 	u64 boot_addr;