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/.
[Note: With regard to cs5535-clockevt.c, Thomas Gleixner asked whether the
timer_irq parameter is required for the driver to work on anything other than
arbitrary hardware which has it mapped to 0. Jens Rottmann replied that the
parameter defaults to 0, which means:
1. autodetect (=keep IRQ BIOS has set up)
2. if that fails use CONFIG_CS5535_MFGPT_DEFAULT_IRQ
(see drivers/misc/cs5535-mfgpt.c: cs5535_mfgpt_set_irq())
Jens further noted that there may not be any systems that have CS5535/36
devices that support EFI and secure boot.]
Suggested-by: Alan Cox <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: Jens Rottmann <Jens.Rottmann@ADLINKtech.com>
cc: linux-kernel@vger.kernel.org
Migrate cs5535 driver to the new 'set-state' interface provided by
the clockevents core, the earlier 'set-mode' interface is marked
obsolete now.
This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Andres Salomon <dilinger@queued.net>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
This patch removes the use of the IRQF_DISABLED flag
It's a NOOP since 2.6.35 and it will be removed one day.
[dlezcano] : slightly changed the changelog
Signed-off-by: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
The clockevent core is able to figure out the best mult and shift,
calculate min_delta_ns and max_delta_ns, with the necessary info passed
into clockevents_config_and_register(). Use this combined configure
and register function where possible to make the codes less error prone
and gain some positive diff stat.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Cc: Andres Salomon <dilinger@queued.net>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Olof Johansson <olof@lixom.net>
Shared timer IRQs are not a good solution, however the Geode platform has
no APIC, IRQs are a scarce resource and there is no technical reason to
forbid it rightaway. Increased latencies and overhead due to sharing are
still better than a driver refusing to load.
Signed-off-by: Jens Rottmann <JRottmann@LiPPERTEmbedded.de>
Acked-by: Andres Salomon <dilinger@queued.net>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
On SMP-capable kernels (e.g. generic distro kernel) the cs5535-clockevt
driver loads but is not actually used.
Setting cpumask to cpu_all_mask works for UP-only kernels, but if compiled
for SMP - though still running on the same UP hardware -
kernel/time/tick-common.c:tick_check_new_device() reads this as
"non-cpu-local" and silently ignores the device.
If we leave cpumask unset clockevents_register_device() will initialize it
and the cs5535-clockevt driver will be used no matter how the kernel was
compiled. Should anyone ever manage to stick a CS553x in an SMP system
(is this even possible?) then a warning will be printed. This is fine as
the cs5535-clockevt driver was never written/tested for SMP.
If bisecting led you here this patch may have exposed a pre-existing MFGPT
problem. Configure for UP-only and re-check.
Signed-off-by: Jens Rottmann <JRottmann@LiPPERTEmbedded.de>
Acked-by: Andres Salomon <dilinger@queued.net>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
My Collabora address is no longer enabled - update the MODULE_AUTHOR
fields of drivers to my current email address.
Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Due to a hardware limitation cs5535_mfgpt_free_timer() cannot actually
release the timer hardware, but it will at least free the now unreferenced
struct associated with it so calling it is the cleaner thing to do.
Signed-off-by: Jens Rottmann <JRottmann@LiPPERTEmbedded.de>
Acked-by: Andres Salomon <dilinger@collabora.co.uk>
Cc: Jordan Crouse <jordan@cosmicpenguin.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
geode-mfgpt: restore previous behavior for selecting IRQ
The MFGPT IRQ used to be, in order of decreasing priority,
* IRQ supplied by the user as a boot-time parameter,
* IRQ previously set by the BIOS or another driver,
* default IRQ given at compile time.
Return to this behavior, which got broken when splitting the
MFGPT/clocksource driver for 2.6.33-rc1.
Signed-off-by: Jens Rottmann <JRottmann@LiPPERTEmbedded.de>
Acked-by: Andres Salomon <dilinger@collabora.co.uk>
Cc: Jordan Crouse <jordan.crouse@amd.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is based on the old code in arch/x86/kernel/mfgpt_32.c, but is
modular and not Geode-specific. There's no reason why the clock event
device needs to be registered so early at boot; the clockevent code is
perfectly capable of dynamic switching.
[akpm@linux-foundation.org: add linux/irq.h include]
Signed-off-by: Andres Salomon <dilinger@collabora.co.uk>
Cc: Jordan Crouse <jordan@cosmicpenguin.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Chris Ball <cjb@laptop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
