diff mbox

[06/39] Annotate hardware config module parameters in drivers/clocksource/

Message ID 148059542480.31612.9946009391236580041.stgit@warthog.procyon.org.uk
State New
Headers show

Commit Message

David Howells Dec. 1, 2016, 12:30 p.m. UTC
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 drivers/clocksource/.

Suggested-by: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Daniel Lezcano <daniel.lezcano@linaro.org>
cc: Thomas Gleixner <tglx@linutronix.de>
cc: linux-kernel@vger.kernel.org

 drivers/clocksource/cs5535-clockevt.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

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diff mbox


diff --git a/drivers/clocksource/cs5535-clockevt.c b/drivers/clocksource/cs5535-clockevt.c
index 9a7e37cf56b0..a1df588343f2 100644
--- a/drivers/clocksource/cs5535-clockevt.c
+++ b/drivers/clocksource/cs5535-clockevt.c
@@ -22,7 +22,7 @@ 
 #define DRV_NAME "cs5535-clockevt"
 static int timer_irq;
-module_param_named(irq, timer_irq, int, 0644);
+module_param_hw_named(irq, timer_irq, int, irq, 0644);
 MODULE_PARM_DESC(irq, "Which IRQ to use for the clock source MFGPT ticks.");