Commit graph

5 commits

Author SHA1 Message Date
Bernhard Kaindl
f212ec4b7b x86: early boot debugging via FireWire (ohci1394_dma=early)
This patch adds a new configuration option, which adds support for a new
early_param which gets checked in arch/x86/kernel/setup_{32,64}.c:setup_arch()
to decide wether OHCI-1394 FireWire controllers should be initialized and
enabled for physical DMA access to allow remote debugging of early problems
like issues ACPI or other subsystems which are executed very early.

If the config option is not enabled, no code is changed, and if the boot
paramenter is not given, no new code is executed, and independent of that,
all new code is freed after boot, so the config option can be even enabled
in standard, non-debug kernels.

With specialized tools, it is then possible to get debugging information
from machines which have no serial ports (notebooks) such as the printk
buffer contents, or any data which can be referenced from global pointers,
if it is stored below the 4GB limit and even memory dumps of of the physical
RAM region below the 4GB limit can be taken without any cooperation from the
CPU of the host, so the machine can be crashed early, it does not matter.

In the extreme, even kernel debuggers can be accessed in this way. I wrote
a small kgdb module and an accompanying gdb stub for FireWire which allows
to gdb to talk to kgdb using remote remory reads and writes over FireWire.

An version of the gdb stub fore FireWire is able to read all global data
from a system which is running a a normal kernel without any kernel debugger,
without any interruption or support of the system's CPU. That way, e.g. the
task struct and so on can be read and even manipulated when the physical DMA
access is granted.

A HOWTO is included in this patch, in Documentation/debugging-via-ohci1394.txt
and I've put a copy online at
ftp://ftp.suse.de/private/bk/firewire/docs/debugging-via-ohci1394.txt

It also has links to all the tools which are available to make use of it
another copy of it is online at:
ftp://ftp.suse.de/private/bk/firewire/kernel/ohci1394_dma_early-v2.diff

Signed-Off-By: Bernhard Kaindl <bk@suse.de>
Tested-By: Thomas Renninger <trenn@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:34:11 +01:00
Adrian Bunk
e658bc556b the scheduled IEEE1394_OUI_DB removal
This patch contains the scheduled IEEE1394_OUI_DB removal.

Signed-off-by: Adrian Bunk <bunk@stusta.de>

Update: Also remove drivers/ieee1394/.gitignore.
Remove now unused struct members in drivers/ieee1394/nodemgr.h.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2007-02-08 20:57:43 +01:00
Randy Dunlap
def4d8733b ieee1394: only build OUI database files if config enabled
Only build IEEE1394 OUI database files if the config option is enabled.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-12-07 21:32:29 +01:00
Jody McIntyre
7301c8d3a0 Remove amdtp, cmp drivers.
Remove the Audio and Music Data Transmission Protocol driver and the
Connection Management Procedures driver.  These are incomplete, have never
worked, and are better implemented in userland via raw1394 (see
http://freebob.sourceforge.net/ for example.)

Signed-off-by: Jody McIntyre <scjody@steamballoon.com>
Cc: Adrian Bunk <bunk@stusta.de>
2005-11-18 00:16:26 -05:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00