linux/lib
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
..
lzo lzo: add some missing casts 2007-07-31 15:39:37 -07:00
reed_solomon [MTD] [NAND] Replace -1 with -EBADMSG in nand error correction code 2007-10-20 22:30:54 +01:00
zlib_deflate [PATCH] zlib_inflate: Upgrade library code to a recent version 2006-06-22 15:05:58 -07:00
zlib_inflate [ZLIB]: Fix external builds of zlib_inflate code. 2007-10-11 22:17:20 -07:00
.gitignore Add some basic .gitignore files 2005-10-18 08:26:15 -07:00
Kconfig Introduce CONFIG_CHECK_SIGNATURE 2007-08-22 19:52:45 -07:00
Kconfig.debug x86: early boot debugging via FireWire (ohci1394_dma=early) 2008-01-30 13:34:11 +01:00
Makefile [LIB]: Introduce struct pcounter 2008-01-28 14:54:39 -08:00
argv_split.c LIB: Replace inappropriate include of <linux/bug.h> 2007-10-20 00:26:10 +02:00
audit.c [PATCH] audit signal recipients 2007-05-11 05:38:25 -04:00
bitmap.c Fix bitmap_scnlistprintf for empty masks 2007-11-05 15:12:32 -08:00
bitrev.c [PATCH] add MODULE_* attributes to bit reversal library 2006-12-10 10:07:52 -08:00
bug.c generic bug: use show_regs() instead of dump_stack() 2007-07-16 09:05:51 -07:00
bust_spinlocks.c handle recursive calls to bust_spinlocks() 2007-10-17 08:42:56 -07:00
check_signature.c uninline check_signature() 2007-07-16 09:05:50 -07:00
cmdline.c [PATCH] Numerous fixes to kernel-doc info in source files. 2007-02-11 10:51:32 -08:00
cpumask.c Safer nr_node_ids and nr_node_ids determination and initial values 2007-05-07 12:12:51 -07:00
crc-ccitt.c [PATCH] kernel-doc for lib/crc*.c 2006-06-25 10:01:20 -07:00
crc-itu-t.c CRC ITU-T V.41 2007-05-10 18:24:13 +02:00
crc7.c CRC7 support 2007-07-17 10:23:04 -07:00
crc16.c [PATCH] kernel-doc for lib/crc*.c 2006-06-25 10:01:20 -07:00
crc32.c Replace __attribute_pure__ with __pure 2007-10-18 14:37:32 -07:00
crc32defs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ctype.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
debug_locks.c [PATCH] lockdep: better lock debugging 2006-07-03 15:27:01 -07:00
dec_and_lock.c [PATCH] atomic: dec_and_lock use atomic primitives 2006-01-08 20:13:48 -08:00
devres.c iomap: implement pcim_iounmap_regions() 2007-04-28 14:15:58 -04:00
div64.c [S390]: Fix build on 31-bit. 2007-04-25 22:28:53 -07:00
dump_stack.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
extable.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
fault-inject.c fault_inject: silence a warning 2007-07-24 12:24:59 -07:00
find_next_bit.c ext4: Add ext4_find_next_bit() 2008-01-28 23:58:27 -05:00
gen_crc32table.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
genalloc.c Slab allocators: Replace explicit zeroing with __GFP_ZERO 2007-07-17 10:23:02 -07:00
halfmd4.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
hexdump.c hexdump: don't print bytes with bit 7 set 2007-11-29 09:24:53 -08:00
hweight.c remove asm/bitops.h includes 2007-10-19 11:53:41 -07:00
idr.c Slab API: remove useless ctor parameter and reorder parameters 2007-10-17 08:42:45 -07:00
inflate.c [PATCH] x86-64: deflate inflate_dynamic too 2007-05-02 19:27:15 +02:00
int_sqrt.c [PATCH] lib: Fix bug in int_sqrt() for 64 bit longs 2006-02-03 08:32:08 -08:00
iomap.c lib/iomap.c:bad_io_access(): print 0x hex prefix 2007-10-17 08:42:57 -07:00
iomap_copy.c [PATCH] add __iowrite64_copy 2006-06-20 20:24:58 -07:00
ioremap.c lib/ioremap.c should #include <linux/io.h> 2007-10-17 08:42:50 -07:00
irq_regs.c [PATCH] irq_reqs: export __irq_regs 2006-10-06 08:53:40 -07:00
kasprintf.c lib: move kasprintf to a separate file 2007-07-31 15:39:39 -07:00
kernel_lock.c sched: remove the !PREEMPT_BKL code 2008-01-25 21:08:33 +01:00
klist.c Driver core: Don't call put methods while holding a spinlock 2006-09-25 21:08:40 -07:00
kobject.c Kobject: fix coding style issues in kobject c files 2008-01-24 21:59:04 -08:00
kobject_uevent.c Kobject: fix coding style issues in kobject c files 2008-01-24 21:59:04 -08:00
kref.c kref: add kref_set() 2008-01-24 20:40:05 -08:00
libcrc32c.c [LIB] crc32c: Keep intermediate crc state in cpu order 2007-11-08 21:34:09 +08:00
list_debug.c [PATCH] More list debugging context 2006-12-07 08:39:35 -08:00
locking-selftest-hardirq.h [PATCH] lockdep: locking API self tests 2006-07-03 15:27:03 -07:00
locking-selftest-mutex.h [PATCH] lockdep: locking API self tests 2006-07-03 15:27:03 -07:00
locking-selftest-rlock-hardirq.h [PATCH] lockdep: locking API self tests 2006-07-03 15:27:03 -07:00
locking-selftest-rlock-softirq.h [PATCH] lockdep: locking API self tests 2006-07-03 15:27:03 -07:00
locking-selftest-rlock.h [PATCH] lockdep: locking API self tests 2006-07-03 15:27:03 -07:00
locking-selftest-rsem.h [PATCH] lockdep: locking API self tests 2006-07-03 15:27:03 -07:00
locking-selftest-softirq.h [PATCH] lockdep: locking API self tests 2006-07-03 15:27:03 -07:00
locking-selftest-spin-hardirq.h [PATCH] lockdep: locking API self tests 2006-07-03 15:27:03 -07:00
locking-selftest-spin-softirq.h [PATCH] lockdep: locking API self tests 2006-07-03 15:27:03 -07:00
locking-selftest-spin.h [PATCH] lockdep: locking API self tests 2006-07-03 15:27:03 -07:00
locking-selftest-wlock-hardirq.h [PATCH] lockdep: locking API self tests 2006-07-03 15:27:03 -07:00
locking-selftest-wlock-softirq.h [PATCH] lockdep: locking API self tests 2006-07-03 15:27:03 -07:00
locking-selftest-wlock.h [PATCH] lockdep: locking API self tests 2006-07-03 15:27:03 -07:00
locking-selftest-wsem.h [PATCH] lockdep: locking API self tests 2006-07-03 15:27:03 -07:00
locking-selftest.c [PATCH] lockdep: show more details about self-test failures 2006-12-07 08:39:43 -08:00
parser.c [AFS]: Make the match_*() functions take const options. 2007-05-03 03:10:39 -07:00
pcounter.c [LIB] pcounter : unline too big functions 2008-01-28 15:00:35 -08:00
percpu_counter.c Add irq protection in the percpu-counters cpu-hotplug-callback path 2007-10-19 11:53:44 -07:00
plist.c [PATCH] pi-futex: add plist implementation 2006-06-27 17:32:46 -07:00
prio_heap.c Fix cpusets update_cpumask 2007-10-19 11:53:41 -07:00
prio_tree.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
proportions.c lib: proportion: fix underflow in prop_norm_percpu() 2007-12-23 12:54:37 -08:00
radix-tree.c avoid negative (and full-width) shifts in radix-tree.c 2007-10-17 08:42:56 -07:00
random32.c [PATCH] severing module.h->sched.h 2006-12-04 02:00:22 -05:00
rbtree.c [PATCH] rbtree: fixed reversed RB_EMPTY_NODE and rb_next/prev 2006-09-30 20:26:56 +02:00
reciprocal_div.c [PATCH] SLAB: use a multiply instead of a divide in obj_to_index() 2006-12-13 09:05:49 -08:00
rwsem-spinlock.c Lockdep: add lockdep_set_class_and_subclass() and lockdep_set_subclass() 2006-10-11 01:45:14 -04:00
rwsem.c x86: fix UML and -regparm=3 2008-01-30 13:33:00 +01:00
scatterlist.c SG: work with the SCSI fixed maximum allocations. 2008-01-28 10:54:49 +01:00
semaphore-sleepers.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
sha1.c [PATCH] Numerous fixes to kernel-doc info in source files. 2007-02-11 10:51:32 -08:00
smp_processor_id.c [PATCH] fix missing includes 2005-10-30 17:37:32 -08:00
sort.c lib/sort.c optimization 2007-10-17 08:42:52 -07:00
spinlock_debug.c Use helpers to obtain task pid in printks 2007-10-19 11:53:43 -07:00
string.c [STRING]: Move strcasecmp/strncasecmp to lib/string.c 2007-04-26 01:54:39 -07:00
swiotlb.c Update swiotlb to use sg helpers 2007-10-22 21:19:58 +02:00
textsearch.c [TEXTSEARCH]: Do not allow zero length patterns in the textsearch infrastructure 2007-12-01 00:03:52 +11:00
ts_bm.c [TEXTSEARCH]: Fix Boyer Moore initialization bug 2006-08-22 14:33:58 -07:00
ts_fsm.c [PATCH] lib/ts_fsm.c: constify structs 2006-09-29 09:18:23 -07:00
ts_kmp.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
vsprintf.c lib: move kasprintf to a separate file 2007-07-31 15:39:39 -07:00