Re: kernel debugging question

[Jon Noack <noackjr@xxxxxxxxxxxxxxx>]

On 05/16/04 13:13, P. de Boer wrote:
> On Sun, 16 May 2004 12:55:35 +0200 Patrick Mauritz wrote:
> > you could probably use qemu (http://fabrice.bellard.free.fr/qemu/),
> > an x86 emulator (similar to bochs, but with dynamic translation for
> > quite good performance) - it allows to attach a gdb to the client 
> > environment.
> >
> > unfortunately there are some linuxisms in the code and the last 
> > freebsd patch I could find - at 
> > http://mail.gnu.org/archive/html/qemu-devel/2004-03/msg00048.html 
> > is pretty dated and doesn't apply to current versions of qemu
> > anymore.
>
> The BSD patch only fails on one chunk on vl.c when applied to the 
> sources of version 0.5.4. That reject is easily fixed by hand.
> However, that wouldn't help much, since dfly doesn't seem to boot on
> it anyway.. (hangs directly after the BTX loader banner)

It looks like the patch was recently committed:
http://savannah.nongnu.org/cgi-bin/viewcvs/qemu/qemu/Changelog.diff?r1=1.47&r2=1.48

Either grab the latest from CVS, wait for 0.5.6, or here's a more recent 
version of the patch:
http://mail.gnu.org/archive/html/qemu-devel/2004-04/msg00054.html

This later patch, bsd.diff, applies with a little fuzz to version 0.5.5 
with the exception of one chunk on vl.c (again).  Applying the attached 
fix.diff to bsd.diff (yes, it's a patch to the patch) allows the 
modified bsd.diff to apply cleanly.  You could also just fix this by hand.

I had to apply the attached sdl.diff to fix SDL detection (change 
'sdl-config' to 'sdl11-config').

This hacked-up 0.5.5 configures, compiles (you need to use gmake), and 
runs fine on FreeBSD 5.2-CURRENT.  The nbench test (from the linux-test 
image) shows that it's about 8 times slower for integer and 13 times 
slower for floating point on my Pentium 4.

I also tried the linux binary on FreeBSD 5.2-CURRENT.  Compared to the 
hacked version I just built, it runs a shade faster for integer but 
significantly slower (>25%) for floating-point.  Finally, note that 
qemu-fast is Linux-specific (requires modified Linux kernel) and will 
just hang on execution.

Jon Noack
--- bsd.diff	Sun May 16 14:38:41 2004
+++ bsd.diff	Sun May 16 14:55:17 2004
@@ -153,7 +153,7 @@
 diff -w -u -d -r1.57 vl.c
 --- vl.c	4 Apr 2004 20:22:28 -0000	1.57
 +++ vl.c	5 Apr 2004 08:02:38 -0000
-@@ -28,24 +28,30 @@
+@@ -28,21 +28,26 @@
  #include <fcntl.h>
  #include <signal.h>
  #include <time.h>
@@ -179,6 +179,10 @@
 +#include <sys/stat.h>
 +#include <libutil.h>
 +#endif
+ #endif
+ 
+ #if defined(CONFIG_SLIRP)
+@@ -50,6 +55,7 @@
  #endif
  
  #ifdef _WIN32

--- configure.orig	Sun May 16 15:02:05 2004
+++ configure	Sun May 16 15:01:21 2004
@@ -204,7 +204,7 @@
 
 if test -z "$sdl" ; then
 
-sdl_config="sdl-config"
+sdl_config="sdl11-config"
 sdl=no
 sdl_static=no