Re: [parisc-linux] kdb_v21 branch updated to -pa26, and kallsyms cross-compile

["Carlos O'Donell Jr." <carlos@baldric.uwo.ca>]

> 
> That's only set like that as a last-dich attempt to get it to work :-(
> 
> I'm going to have to give up on this, I can't spend all week trying to get it to
> work. What I don't understand is that I move a working .config to the new kernel
> source and both the serial console AND the scsi stop working.
> 
> Ah well, it was a nice idea while it lasted. It's just a bit hard debugging code
> when the only error you get is "Stack pointer and cr30 do not cor
> respond" repeated endlessly....
> 
> patrick
>

You can't always copy a .config from kernel to kernel. The kernel source
dictates what will be _in_ the .config. I usually run 'make mrproper'
and then have 'make oldconfig' or 'make ???config' recreate the config files
to suit the material in the kernel.

When switching to a new source tree I recommend:
make mrproper
make oldconfig
make menuconfig (to suit your tastes)
...


As for the endless 'Stack pointer and cr30 do not correspond!'....

I believe that is a bug in traps.c and I have code to give a proper dump.
I haven't been able to get anyone who knows to explain how the dump_stack in 
traps should _really_ work :)

AFAI understand the following works (I've tested it on my kernels with what 
looks to be a successfull dump while doing some bad things (props to Bame
for helping me out) ;)

BTW, what led me to this solution is that the printk in the else is
completely bogus... so I rewrote the else.

Q: When do you get 'Stack pointer and cr30 do not correspond'?

==========
--- ./linux/arch/parisc/kernel/traps.c     Tue May 21 00:01:37 2002
+++ ./linux/arch/parisc/kernel/traps.c     Tue May 21 00:30:42 2002
@@ -189,10 +189,25 @@
                }
                else
                {
-                   /* Stack Dump! */
-                   printk(KERN_CRIT "WARNING! Stack pointer and cr30 do not correspond!\n");
-                   printk(KERN_CRIT "Dumping virtual address stack instead\n");
-                   dump_stack((unsigned long)__va(stack_start), (unsigned long)__va(sp), 0);
+
+                   stack_start = sp & ~(INIT_TASK_SIZE - 1);
+                   if (stack_start == cr30) {
+
+                       /* We're in a non-interrupt stack and cr30 matches
+                          the start of the stack */
+
+                       dump_stack(stack_start, sp, 0);
+
+                   }
+                   else
+                   {
+
+                       /* Stack Dump! */
+                       printk(KERN_CRIT "WARNING! Stack pointer and cr30 do not correspond!\n");
+                       printk(KERN_CRIT "Dumping virtual address stack instead\n");
+                       dump_stack((unsigned long)__va(stack_start), (unsigned long)__va(sp), 0);
+
+                   }
                }
        }
 #endif
==========