[linuxsh-dev] mmu problems?

[Bryan R. <br...@ix...>]

Hello linuxsh-dev,

I have been working with the latest CVS kernel sources, putting in
printk statements as reach points trying to figure out why the only
thing I am getting in GDB is the kernel banner. It looks like the
problem lies in setup_arch, called right after printk(linux_banner).
That routine executes fine, until  it calls paging_init (at the last
line of setup_arch). As soon as the MMU is brought up, printk stops
working:

[from arch/sh/mm/init.c:paging_init]

        printk("paging here 1\n");

        /* Enable MMU */
        ctrl_outl(MMU_CONTROL_INIT, MMUCR);

        /* The manual suggests doing some nops after turning on the MMU
*/
        asm volatile("nop;nop;nop;nop;nop;nop;");
        
        printk("paging here 2\n");

All I get with GDB is "paging here 1" and then nothing else. As I
mentioned before if I exit GDB and go into a terminal program, the
sh-ipl menu is back up as if GDB mode exited (suggesting the kernel
died/returned). Of course I have no way of knowing how much of the
kernel executed since printk stops working. I am not passing a console
parameter to the kernel.

Is it normal for LinuxSH BIOS-based printk to break after bringing up
the MMU? If so, how do I fix it--I would like all console output to go
into GDB. And if I am having MMU problems, could that be the result of
incorrect sh-ipl init_bsc code?

Thanks,

Bryan Rittmeyer
mailto:br...@ix...
[slowing getting this SH4 board running Linux]