Re: PPC KGDB changes and some help?

[George Anzinger <george@mvista.com>]

Tom Rini wrote:
> On Wed, Jan 21, 2004 at 10:23:12PM +0530, Amit S. Kale wrote:
> 
> 
>>Hi,
>>
>>Here it is: ppc kgdb from timesys kernel is available at
>>http://kgdb.sourceforge.net/kgdb-2/linux-2.6.1-kgdb-2.1.0.tar.bz2
>>
>>This is my attempt at extracting kgdb from TimeSys kernel. It works well in 
>>TimeSys kernel, so blame me if above patch doesn't work.
> 
> 
> Okay, here's my first patch against this.
> ===== kernel/kgdbstub.c 1.1 vs edited =====
> --- 1.1/kernel/kgdbstub.c	Wed Jan 21 10:13:17 2004
> +++ edited/kernel/kgdbstub.c	Wed Jan 21 10:53:38 2004
> @@ -1058,9 +1058,6 @@
>  	kgdb_serial->write_char('+');
>  
>  	linux_debug_hook = kgdb_handle_exception;
> -	
> -	if (kgdb_ops->kgdb_init)
> -		kgdb_ops->kgdb_init();
>  
>  	/* We can't do much if this fails */
>  	register_module_notifier(&kgdb_module_load_nb);
> @@ -1104,6 +1101,11 @@
>  	if (!kgdb_enter) {
>  		return;
>  	}
> +
> +	/* Let the arch do any initalization it needs to */
> +	if (kgdb_ops->kgdb_init)
> +		kgdb_ops->kgdb_init();
> +
>  	if (!kgdb_serial) {
>  		printk("KGDB: no gdb interface available.\n"
>  		       "kgdb can't be enabled\n");
> 
> I'm not sure why you were calling the arch-specific init so late in the
> process, but since it's a nop on both i386 and x86_64 (so perhaps it
> should be removed for both of these?), this change doesn't matter to
> them.  But it does make the PPC code cleaner, IMHO.

I agree.  Lets dump all the init calls/code.  I have not seen anything yet that 
can not be done as a side effect of the first call, or better yet, at compile time.

I am willing to be shown a valid case, however.  Remember, I want to be able to 
do a breakpoint() as the first line of C code in the kernel.  (works with the mm 
kgdb).
> 

-- 
George Anzinger   george@mvista.com
High-res-timers:  http://sourceforge.net/projects/high-res-timers/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml