From: Markus Duft <markus.duft@salomon.at>
To: qemu-devel@nongnu.org, gdb@sourceware.org
Subject: [Qemu-devel] Debugging a 64-bit kernel in qemu
Date: Mon, 03 Jan 2011 11:27:00 +0100 [thread overview]
Message-ID: <4D21A474.2040909@salomon.at> (raw)
Hi!
I have been playing a little with this: I'm writing a kernel for both x86 and x86-64. While doing so, i'd like to debug the kernel using qemu (and it's gdb stub) and gdb. This worked very well until qemu-0.11.1 (gdb version does not seem to play any role...). From there on, debugging the 64 bit version no longer works. My sessions look like this with qemu-0.13.50 (and any version above 0.11.1, actually...):
mduft@s01en22 /big/Privat/osdev/tachyon2 $ x86_64-pc-linux-gnu-gdb .build/x86_64/x86_64-tachyon
GNU gdb (GDB) 7.2.50.20110103-cvs
[snip]
Reading symbols from /big/Privat/osdev/tachyon2/.build/x86_64/x86_64-tachyon...done.
(gdb) target remote:1234
Remote debugging using :1234
0x0000000000000000 in ?? ()
(gdb) b boot
Breakpoint 1 at 0xffffffff80119000: file /big/Privat/osdev/tachyon2/core/tachyon.boot/Entry.cc, line 25.
(gdb) c
Continuing.
Remote 'g' packet reply is too long: 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
000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000801f0000
(gdb) quit
actuallly, i _can_ debug the kernel, nut only until the long mode switch occurs. after this point: no luck... :[
now for the questions:
1) is this a problem with qemu or was qemu "fixed" and gdb has a problem?
(that's why i CCd the gdb list ;)).
2) is there any plan to fix this issue?
3) is there some kind of workaround i can use (i'd be happy with an ugly/unsupported patch too, since i build all my stuff myself ;)).
Thanks in advance!
Regards, Markus
next reply other threads:[~2011-01-03 10:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-03 10:27 Markus Duft [this message]
2011-01-03 11:15 ` [Qemu-devel] Re: Debugging a 64-bit kernel in qemu Jan Kiszka
2011-01-03 12:15 ` Markus Duft
2011-01-03 12:27 ` Markus Duft
2011-01-03 13:00 ` Jan Kiszka
2011-01-03 13:12 ` Markus Duft
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