[linuxsh-dev] loading kernel with gdb

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

Mitch Davis wrote:

> Give the GDB stub a try as well.  Please note that Greg and I had
> troubles with loading the kernel with the stub that went away
> when we hacked the linker script so the kernel was linked to run
> at 0x80000000 but load at 0xA0000000 (the uncached area).  Please
> tell me if you're interested in our patch.  (Niibe-san didn't
> like it - he thinks we'd be better off finding the cause of this
> problem).

Can you give me more info on this patch and what your problem was? Now
that I have the GDB stub working, I am running into early trouble with
the kernel. Here is the GDB output:

---
bryan@mtdew:~/cvs/sh/kernel$ sh-linux-gnu-gdb
GNU gdb 4.18
Copyright 1998 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you
are
welcome to change it and/or distribute copies of it under certain
conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for
details.
This GDB was configured as "--host=i686-pc-linux-gnu
--target=sh-linux-gnu".
0x8000402 in ?? ()
Loading section .empty_zero_page, size 0x1c lma 0x88101000
Loading section .text, size 0x63ce8 lma 0x88102000
Loading section .rodata, size 0xdd37 lma 0x88165ce8
Loading section __ex_table, size 0x1208 lma 0x88173a20
Loading section .data, size 0x6ab8 lma 0x88174c28
Loading section .exitcall.exit, size 0x14 lma 0x8817b6e0
Loading section .data.init_task, size 0x2000 lma 0x8817c000
Loading section .text.init, size 0x5878 lma 0x8817e000
Loading section .data.init, size 0x2db lma 0x88183878
Loading section .setup.init, size 0x88 lma 0x88183b60
Loading section .initcall.init, size 0x34 lma 0x88183be8
Loading section .machvec.init, size 0x2f8 lma 0x88183c1c
Loading section .data.cacheline_aligned, size 0xac0 lma 0x88184000
Start address 0x88102000 , load size 532694
Transfer rate: 29188 bits/sec.
(gdb) cont
Continuing.
Can't send signals to this remote system.  SIGBUS not sent.

Program received signal SIGBUS, Bus error.
0x88102000 in _stext ()
(gdb) 
---

What a letdown... I thought it would work the first time. ;-) Any idea
what can cause a SIGBUS before the first line of kernel output even
shows up?

(Same problem with the CVS kernel source and with linux-2.4.0-test6)

Thanks,

Bryan Rittmeyer
mailto:br...@ix...