When the kernel is running in secure boot mode, we lock down the kernel to
prevent userspace from modifying the running kernel image. Whilst this
includes prohibiting access to things like /dev/mem, it must also prevent
access by means of configuring driver modules in such a way as to cause a
device to access or modify the kernel image.
To this end, annotate module_param* statements that refer to hardware
configuration and indicate for future reference what type of parameter they
specify. The parameter parser in the core sees this information and can
skip such parameters with an error message if the kernel is locked down.
The module initialisation then runs as normal, but just sees whatever the
default values for those parameters is.
Note that we do still need to do the module initialisation because some
drivers have viable defaults set in case parameters aren't specified and
some drivers support automatic configuration (e.g. PNP or PCI) in addition
to manually coded parameters.
This patch annotates drivers in arch/x86/mm/.
[Note: With respect to testmmiotrace, an additional patch will be added
separately that makes the module refuse to load if the kernel is locked
down.]
Suggested-by: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
cc: Ingo Molnar <mingo@kernel.org>
cc: Thomas Gleixner <tglx@linutronix.de>
cc: "H. Peter Anvin" <hpa@zytor.com>
cc: x86@kernel.org
cc: linux-kernel@vger.kernel.org
cc: nouveau@lists.freedesktop.org
After every iounmap mmiotrace has to free kmmio_fault_pages, but
it can't do it directly, so it defers freeing by RCU.
It usually works, but when mmiotraced code calls ioremap-iounmap
multiple times without sleeping between (so RCU won't kick in
and start freeing) it can be given the same virtual address, so
at every iounmap mmiotrace will schedule the same pages for
release. Obviously it will explode on second free.
Fix it by marking kmmio_fault_pages which are scheduled for
release and not adding them second time.
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Tested-by: Marcin Kocielnicki <koriakin@0x04.net>
Tested-by: Shinpei KATO <shinpei@il.is.s.u-tokyo.ac.jp>
Acked-by: Pekka Paalanen <pq@iki.fi>
Cc: Stuart Bennett <stuart@freedesktop.org>
Cc: Marcin Kocielnicki <koriakin@0x04.net>
Cc: nouveau@lists.freedesktop.org
Cc: <stable@kernel.org>
LKML-Reference: <20100613215654.GA3829@joi.lan>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Apparently pages far into an ioremapped region might not actually be
mapped during ioremap(). Add an optional read test to try to trigger a
multiply faulting MMIO access. Also add more messages to the kernel log
to help debugging.
This patch is based on a patch suggested by
Stuart Bennett <stuart@freedesktop.org>
who discovered bugs in mmiotrace related to normal kernel space faults.
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Cc: Stuart Bennett <stuart@freedesktop.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Check the read values against the written values in the MMIO read/write
test. This test shows if the given MMIO test area really works as
memory, which is a prerequisite for a successful mmiotrace test.
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Cc: Stuart Bennett <stuart@freedesktop.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Offer mmiotrace users a function to inject markers from inside the kernel.
This depends on the trace_vprintk() patch.
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
David Howells