linux-stable.git/drivers/clocksource, branch v3.16.78

clocksource/drivers/exynos_mct: Fix error path in timer resources initialization

2019-07-09T21:04:06+00:00

commit b9307420196009cdf18bad55e762ac49fb9a80f4 upstream.

While freeing interrupt handlers in error path, don't assume that all
requested interrupts are per-processor interrupts and properly release
standard interrupts too.

Reported-by: Krzysztof Kozlowski 
Fixes: 56a94f13919c ("clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier")
Signed-off-by: Marek Szyprowski 
Reviewed-by: Krzysztof Kozlowski 
Reviewed-by: Chanwoo Choi 
Signed-off-by: Daniel Lezcano 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

clockevents/drivers/i8253: Add support for PIT shutdown quirk

2019-02-11T17:53:47+00:00

commit 35b69a420bfb56b7b74cb635ea903db05e357bec upstream.

Add support for platforms where pit_shutdown() doesn't work because of a
quirk in the PIT emulation. On these platforms setting the counter register
to zero causes the PIT to start running again, negating the shutdown.

Provide a global variable that controls whether the counter register is
zero'ed, which platform specific code can override.

Signed-off-by: Michael Kelley 
Signed-off-by: Thomas Gleixner 
Cc: "gregkh@linuxfoundation.org" 
Cc: "devel@linuxdriverproject.org" 
Cc: "daniel.lezcano@linaro.org" 
Cc: "virtualization@lists.linux-foundation.org" 
Cc: "jgross@suse.com" 
Cc: "akataria@vmware.com" 
Cc: "olaf@aepfle.de" 
Cc: "apw@canonical.com" 
Cc: vkuznets 
Cc: "jasowang@redhat.com" 
Cc: "marcelo.cerri@canonical.com" 
Cc: KY Srinivasan 
Link: https://lkml.kernel.org/r/1541303219-11142-2-git-send-email-mikelley@microsoft.com
[bwh: Backported to 3.16:
 - Don't use __ro_after_init
 - Adjust context, indentation]
Signed-off-by: Ben Hutchings

clocksource/drivers/fsl_ftm_timer: Fix error return checking

2018-06-16T21:22:25+00:00

commit f287eb9013ccf199cbfa4eabd80c36fedfc15a73 upstream.

The error checks on freq for a negative error return always fails because
freq is unsigned and can never be negative. Fix this by making freq a
signed long.

Detected with Coccinelle:
drivers/clocksource/fsl_ftm_timer.c:287:5-9: WARNING: Unsigned expression
compared with zero: freq <= 0
drivers/clocksource/fsl_ftm_timer.c:291:5-9: WARNING: Unsigned expression
compared with zero: freq <= 0

Fixes: 2529c3a33079 ("clocksource: Add Freescale FlexTimer Module (FTM) timer support")
Signed-off-by: Colin Ian King 
Signed-off-by: Thomas Gleixner 
Cc: Daniel Lezcano 
Cc: kernel-janitors@vger.kernel.org
Link: https://lkml.kernel.org/r/20180226113614.3092-1-colin.king@canonical.com
Signed-off-by: Ben Hutchings

clocksource/exynos_mct: Clear interrupt when cpu is shut down

2017-03-16T02:27:00+00:00

commit bc7c36eedb0c7004aa06c2afc3c5385adada8fa3 upstream.

When a CPU goes offline a potentially pending timer interrupt is not
cleared. When the CPU comes online again then the pending interrupt is
delivered before the per cpu clockevent device is initialized. As a
consequence the tick interrupt handler dereferences a NULL pointer.

[   51.251378] Unable to handle kernel NULL pointer dereference at virtual address 00000040
[   51.289348] task: ee942d00 task.stack: ee960000
[   51.293861] PC is at tick_periodic+0x38/0xb0
[   51.298102] LR is at tick_handle_periodic+0x1c/0x90

Clear the pending interrupt in the cpu dying path.

Fixes: 56a94f13919c ("clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier")
Reported-by: Seung-Woo Kim 
Signed-off-by: Joonyoung Shim 
Cc: linux-samsung-soc@vger.kernel.org
Cc: cw00.choi@samsung.com
Cc: daniel.lezcano@linaro.org
Cc: javier@osg.samsung.com
Cc: kgene@kernel.org
Cc: krzk@kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1484628876-22065-1-git-send-email-jy0922.shim@samsung.com
Signed-off-by: Thomas Gleixner 
[bwh: Backported to 3.16: add definition of the 'mevt' variable, added earlier
 upstream]
Signed-off-by: Ben Hutchings

clocksource/drivers/sun4i: Clear interrupts after stopping timer in probe function

2016-11-20T01:17:18+00:00

commit b53e7d000d9e6e9fd2c6eb6b82d2783c67fd599e upstream.

The bootloader (U-boot) sometimes uses this timer for various delays.
It uses it as a ongoing counter, and does comparisons on the current
counter value. The timer counter is never stopped.

In some cases when the user interacts with the bootloader, or lets
it idle for some time before loading Linux, the timer may expire,
and an interrupt will be pending. This results in an unexpected
interrupt when the timer interrupt is enabled by the kernel, at
which point the event_handler isn't set yet. This results in a NULL
pointer dereference exception, panic, and no way to reboot.

Clear any pending interrupts after we stop the timer in the probe
function to avoid this.

Signed-off-by: Chen-Yu Tsai 
Signed-off-by: Daniel Lezcano 
Acked-by: Maxime Ripard 
Signed-off-by: Ben Hutchings

clocksource/drivers/vt8500: Increase the minimum delta

2016-02-02T19:09:28+00:00

commit f9eccf24615672896dc13251410c3f2f33a14f95 upstream.

The vt8500 clocksource driver declares itself as capable to handle the
minimum delay of 4 cycles by passing the value into
clockevents_config_and_register(). The vt8500_timer_set_next_event()
requires the passed cycles value to be at least 16. The impact is that
userspace hangs in nanosleep() calls with small delay intervals.

This problem is reproducible in Linux 4.2 starting from:
c6eb3f70d448 ('hrtimer: Get rid of hrtimer softirq')

From Russell King, more detailed explanation:

"It's a speciality of the StrongARM/PXA hardware. It takes a certain
number of OSCR cycles for the value written to hit the compare registers.
So, if a very small delta is written (eg, the compare register is written
with a value of OSCR + 1), the OSCR will have incremented past this value
before it hits the underlying hardware. The result is, that you end up
waiting a very long time for the OSCR to wrap before the event fires.

So, we introduce a check in set_next_event() to detect this and return
-ETIME if the calculated delta is too small, which causes the generic
clockevents code to retry after adding the min_delta specified in
clockevents_config_and_register() to the current time value.

min_delta must be sufficient that we don't re-trip the -ETIME check - if
we do, we will return -ETIME, forward the next event time, try to set it,
return -ETIME again, and basically lock the system up. So, min_delta
must be larger than the check inside set_next_event(). A factor of two
was chosen to ensure that this situation would never occur.

The PXA code worked on PXA systems for years, and I'd suggest no one
changes this mechanism without access to a wide range of PXA systems,
otherwise they're risking breakage."

Cc: Russell King 
Acked-by: Alexey Charkov 
Signed-off-by: Roman Volkov 
Signed-off-by: Daniel Lezcano 
Signed-off-by: Luis Henriques

clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier

2015-07-15T09:00:56+00:00

commit 56a94f13919c0db5958611b388e1581b4852f3c9 upstream.

Whilst testing cpu hotplug events on kernel configured with
DEBUG_PREEMPT and DEBUG_ATOMIC_SLEEP we get following BUG message,
caused by calling request_irq() and free_irq() in the context of
hotplug notification (which is in this case atomic context).

[   40.785859] CPU1: Software reset
[   40.786660] BUG: sleeping function called from invalid context at mm/slub.c:1241
[   40.786668] in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: swapper/1
[   40.786678] Preemption disabled at:[<  (null)>]   (null)
[   40.786681]
[   40.786692] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.19.0-rc4-00024-g7dca860 #36
[   40.786698] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[   40.786728] [] (unwind_backtrace) from [] (show_stack+0x10/0x14)
[   40.786747] [] (show_stack) from [] (dump_stack+0x70/0xbc)
[   40.786767] [] (dump_stack) from [] (kmem_cache_alloc+0xd8/0x170)
[   40.786785] [] (kmem_cache_alloc) from [] (request_threaded_irq+0x64/0x128)
[   40.786804] [] (request_threaded_irq) from [] (exynos4_local_timer_setup+0xc0/0x13c)
[   40.786820] [] (exynos4_local_timer_setup) from [] (exynos4_mct_cpu_notify+0x30/0xa8)
[   40.786838] [] (exynos4_mct_cpu_notify) from [] (notifier_call_chain+0x44/0x84)
[   40.786857] [] (notifier_call_chain) from [] (__cpu_notify+0x28/0x44)
[   40.786873] [] (__cpu_notify) from [] (secondary_start_kernel+0xec/0x150)
[   40.786886] [] (secondary_start_kernel) from [<40008764>] (0x40008764)

Interrupts cannot be requested/freed in the CPU_STARTING/CPU_DYING
notifications which run on the hotplugged cpu with interrupts and
preemption disabled.

To avoid the issue, request the interrupts for all possible cpus in
the boot code. The interrupts are marked NO_AUTOENABLE to avoid a racy
request_irq/disable_irq() sequence. The flag prevents the
request_irq() code from enabling the interrupt immediately.

The interrupt is then enabled in the CPU_STARTING notifier of the
hotplugged cpu and again disabled with disable_irq_nosync() in the
CPU_DYING notifier.

[ tglx: Massaged changelog to match the patch ]

Fixes: 7114cd749a12 ("clocksource: exynos_mct: use (request/free)_irq calls for local timer registration")
Reported-by: Krzysztof Kozlowski 
Reviewed-by: Krzysztof Kozlowski 
Tested-by: Krzysztof Kozlowski 
Tested-by: Marcin Jabrzyk 
Signed-off-by: Damian Eppel 
Cc: m.szyprowski@samsung.com
Cc: kyungmin.park@samsung.com
Cc: daniel.lezcano@linaro.org
Cc: kgene@kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1435324984-7328-1-git-send-email-d.eppel@samsung.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Luis Henriques

clockevents: sun5i: Fix setup_irq init sequence

2015-03-30T10:10:59+00:00

commit 1096be084ac59927158ce80ff1d31c33eed0e565 upstream.

The interrupt is enabled before the handler is set. Even this bug
did not appear, it is potentially dangerous as it can lead to a
NULL pointer dereference.

Fix the error by enabling the interrupt after
clockevents_config_and_register() is called.

Signed-off-by: Yongbae Park 
Signed-off-by: Daniel Lezcano 
Signed-off-by: Luis Henriques

clocksource: efm32: Fix a NULL pointer dereference

2015-03-30T10:10:57+00:00

commit 7b8f10da3bf1056546133c9f54f49ce389fd95ab upstream.

The initialisation of the efm32 clocksource first sets up the irq and only
after that initialises the data needed for irq handling. In case this
initialisation is delayed the irq handler would dereference a NULL pointer.

I'm not aware of anything that could delay the process in such a way, but it's
better to be safe than sorry, so setup the irq only when the clock event device
is ready.

Acked-by: Uwe Kleine-König 
Signed-off-by: Yongbae Park 
Signed-off-by: Daniel Lezcano 
Signed-off-by: Luis Henriques

clocksource: arch_timer: Only use the virtual counter (CNTVCT) on arm64

2015-02-04T10:58:31+00:00

commit d6ad36913083d683aad4e02e53580c995f1a6ede upstream.

Commit 0b46b8a718c6 (clocksource: arch_timer: Fix code to use physical
timers when requested) introduces the use of physical counters in the
ARM architected timer driver. However, he arm64 kernel uses CNTVCT in
VDSO. When booting in EL2, the kernel switches to the physical timers to
make things easier for KVM but it continues to use the virtual counter
both in user and kernel. While in such scenario CNTVCT == CNTPCT (since
CNTVOFF is initialised by the kernel to 0), we want to spot firmware
bugs corrupting CNTVOFF early (which would affect CNTVCT).

Signed-off-by: Catalin Marinas 
Tested-by: Yingjoe Chen 
Cc: Daniel Lezcano 
Signed-off-by: Arnd Bergmann 
Cc: Mark Rutland 
Signed-off-by: Luis Henriques