linux-toradex.git/drivers/clocksource, branch v4.4.93

clocksource/exynos_mct: Clear interrupt when cpu is shut down

2017-01-26T07:23:48+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 
Signed-off-by: Greg Kroah-Hartman

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

2016-09-24T08:07:35+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: Greg Kroah-Hartman

clockevents/tcb_clksrc: Prevent disabling an already disabled clock

2016-03-03T23:07:15+00:00

commit f02b4b72d12cbae7020a959e2ed0410a464b4cc4 upstream.

clockevents_exchange_device is calling clockevents_shutdown() on the new
clockenvents device but it may have never been enabled in the first place.
This results in the tcb clock being disabled without being enabled first:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at drivers/clk/clk.c:680 clk_disable+0x28/0x34()
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 4.4.0+ #6
Hardware name: Atmel AT91SAM9
[] (unwind_backtrace) from [] (show_stack+0x10/0x14)
[] (show_stack) from [] (warn_slowpath_common+0x78/0xa0)
[] (warn_slowpath_common) from [] (warn_slowpath_null+0x18/0x20)
[] (warn_slowpath_null) from [] (clk_disable+0x28/0x34)
[] (clk_disable) from [] (tc_shutdown+0x38/0x4c)
[] (tc_shutdown) from [] (clockevents_switch_state+0x38/0x6c)
[] (clockevents_switch_state) from [] (clockevents_shutdown+0x10/0x24)
[] (clockevents_shutdown) from [] (tick_check_new_device+0x84/0xac)
[] (tick_check_new_device) from [] (clockevents_register_device+0x7c/0x108)
[] (clockevents_register_device) from [] (tcb_clksrc_init+0x390/0x3e8)
[] (tcb_clksrc_init) from [] (do_one_initcall+0x114/0x1d4)
[] (do_one_initcall) from [] (kernel_init_freeable+0xfc/0x1b8)
[] (kernel_init_freeable) from [] (kernel_init+0x8/0xe0)
[] (kernel_init) from [] (ret_from_fork+0x14/0x24)
---[ end trace 0000000000000001 ]---

Check what state we were in before trying to disable the clock.

Fixes: cf4541c101ea ("clockevents/drivers/tcb_clksrc: Migrate to new 'set-state' interface")
Signed-off-by: Alexandre Belloni 
Cc: Nicolas Ferre 
Cc: Boris Brezillon 
Cc: linux-arm-kernel@lists.infradead.org
Cc: Daniel Lezcano 
Link: http://lkml.kernel.org/r/1452854061-30370-1-git-send-email-alexandre.belloni@free-electrons.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

clocksource/drivers/vt8500: Increase the minimum delta

2016-03-03T23:07:11+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: Greg Kroah-Hartman

clocksource: Mmio: remove artificial 32bit limitation

2015-12-10T18:37:18+00:00

The EP93xx is registering a clocksource of 40 bits with
clocksource_mmio_init() but this is not working because of this
artificial limitation. It works fine to lift the uppe limit to
64 bits, and since cycle_t is u64, it should intuitively have been
like that from the beginning.

Fixes: 000bc17817bf "ARM: ep93xx: switch to GENERIC_CLOCKEVENTS"
Reported-by: Alexander Sverdlin 
Signed-off-by: Linus Walleij 
Cc: Daniel Lezcano 
Link: http://lkml.kernel.org/r/1449768101-6879-1-git-send-email-linus.walleij@linaro.org
Signed-off-by: Thomas Gleixner

clocksource: Disallow drivers for ARCH_USES_GETTIMEOFFSET

2015-11-16T18:07:08+00:00

We can now select clocksource drivers like ti-32k and CONFIG_OF
on ancient machines that still use gettimeoffset, and the combination
results in a link error.

arch/arm/kernel/built-in.o: In function `time_init':
(.init.text+0xc28): undefined reference to `clocksource_probe'

The reason for this is that the Makefile is hidden behind
CONFIG_ARCH_USES_GETTIMEOFFSET, but the Kconfig file is not, and
it has shown up just now because the ti-32k driver was added
and can be selected using COMPILE_TEST on all platforms.

This patch hides the Kconfig menu in CONFIG_ARCH_USES_GETTIMEOFFSET
as well.

Fixes: dfedaf105d60 "clocksource: ti-32k: make it depend on GENERIC_CLOCKSOURCE"
Signed-off-by: Arnd Bergmann 
Cc: linux-arm-kernel@lists.infradead.org
Cc: Felipe Balbi 
Cc: Tony Lindgren 
Cc: Daniel Lezcano 
Link: http://lkml.kernel.org/r/7579471.4N90fYPQOK@wuerfel
Signed-off-by: Thomas Gleixner

clocksource/fsl: Avoid harmless 64-bit warnings

2015-11-16T18:07:08+00:00

The ftm_clockevent_init passes the value of "~0UL" into a function
that takes a 32-bit argument, which drops the upper 32 bits, as
gcc warns about on ARM64:

clocksource/fsl_ftm_timer.c: In function 'ftm_clockevent_init':
clocksource/fsl_ftm_timer.c:206:13: warning: large integer implicitly truncated to unsigned type [-Woverflow]

This was obviously unintended behavior, and is easily avoided by
using '~0u' as the integer literal, because that is 32-bit wide
on all architectures.

Signed-off-by: Arnd Bergmann 
Cc: linux-arm-kernel@lists.infradead.org
Cc: Xiubo Li 
Cc: Shawn Guo 
Cc: Sascha Hauer 
Cc: Stefan Agner 
Cc: Daniel Lezcano 
Link: http://lkml.kernel.org/r/3990834.xnjhm37Grs@wuerfel
Signed-off-by: Thomas Gleixner

Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus

2015-11-15T17:10:53+00:00

Pull MIPS updates from Ralf Baechle:
 "These are the highlists of the main MIPS pull request for 4.4:

   - Add latencytop support
   - Support appended DTBs
   - VDSO support and initially use it for gettimeofday.
   - Drop the .MIPS.abiflags and ELF NOTE sections from vmlinux
   - Support for the 5KE, an internal test core.
   - Switch all MIPS platfroms to libata drivers.
   - Improved support, cleanups for ralink and Lantiq platforms.
   - Support for the new xilfpga platform.
   - A number of DTB improvments for BMIPS.
   - Improved support for CM and CPS.
   - Minor JZ4740 and BCM47xx enhancements"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (120 commits)
  MIPS: idle: add case for CPU_5KE
  MIPS: Octeon: Support APPENDED_DTB
  MIPS: vmlinux: create a section for appended DTB
  MIPS: Clean up compat_siginfo_t
  MIPS: Fix PAGE_MASK definition
  MIPS: BMIPS: Enable GZIP ramdisk and timed printks
  MIPS: Add xilfpga defconfig
  MIPS: xilfpga: Add mipsfpga platform code
  MIPS: xilfpga: Add xilfpga device tree files.
  dt-bindings: MIPS: Document xilfpga bindings and boot style
  MIPS: Make MIPS_CMDLINE_DTB default
  MIPS: Make the kernel arguments from dtb available
  MIPS: Use USE_OF as the guard for appended dtb
  MIPS: BCM63XX: Use pr_* instead of printk
  MIPS: Loongson: Cleanup CONFIG_LOONGSON_SUSPEND.
  MIPS: lantiq: Disable xbar fpi burst mode
  MIPS: lantiq: Force the crossbar to big endian
  MIPS: lantiq: Initialize the USB core on boot
  MIPS: lantiq: Return correct value for fpi clock on ar9
  MIPS: ralink: Add missing clock on rt305x
  ...

MIPS: VDSO: Add implementations of gettimeofday() and clock_gettime()

2015-11-11T07:36:41+00:00

Add user-mode implementations of gettimeofday() and clock_gettime() to
the VDSO. This is currently usable with 2 clocksources: the CP0 count
register, which is accessible to user-mode via RDHWR on R2 and later
cores, or the MIPS Global Interrupt Controller (GIC) timer, which
provides a "user-mode visible" section containing a mirror of its
counter registers. This section must be mapped into user memory, which
is done below the VDSO data page.

When a supported clocksource is not in use, the VDSO functions will
return -ENOSYS, which causes libc to fall back on the standard syscall
path.

When support for neither of these clocksources is compiled into the
kernel at all, the VDSO still provides clock_gettime(), as the coarse
realtime/monotonic clocks can still be implemented. However,
gettimeofday() is not provided in this case as nothing can be done
without a suitable clocksource. This causes the symbol lookup to fail
in libc and it will then always use the standard syscall path.

This patch includes a workaround for a bug in QEMU which results in
RDHWR on the CP0 count register always returning a constant (incorrect)
value. A fix for this has been submitted, and the workaround can be
removed after the fix has been in stable releases for a reasonable
amount of time.

A simple performance test which calls gettimeofday() 1000 times in a
loop and calculates the average execution time gives the following
results on a Malta + I6400 (running at 20MHz):

 - Syscall:    ~31000 ns
 - VDSO (GIC): ~15000 ns
 - VDSO (CP0): ~9500 ns

[markos.chandras@imgtec.com:
- Minor code re-arrangements in order for mappings to be made
in the order they appear to the process' address space.
- Move do_{monotonic, realtime} outside of the MIPS_CLOCK_VSYSCALL ifdef
- Use gic_get_usm_range so we can do the GIC mapping in the
arch/mips/kernel/vdso instead of the GIC irqchip driver]

Signed-off-by: Alex Smith 
Signed-off-by: Markos Chandras 
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11338/
Signed-off-by: Ralf Baechle

Merge tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc

2015-11-10T23:00:03+00:00

Pull ARM SoC driver updates from Olof Johansson:
 "As we've enabled multiplatform kernels on ARM, and greatly done away
  with the contents under arch/arm/mach-*, there's still need for
  SoC-related drivers to go somewhere.

  Many of them go in through other driver trees, but we still have
  drivers/soc to hold some of the "doesn't fit anywhere" lowlevel code
  that might be shared between ARM and ARM64 (or just in general makes
  sense to not have under the architecture directory).

  This branch contains mostly such code:

   - Drivers for qualcomm SoCs for SMEM, SMD and SMD-RPM, used to
     communicate with power management blocks on these SoCs for use by
     clock, regulator and bus frequency drivers.

   - Allwinner Reduced Serial Bus driver, again used to communicate with
     PMICs.

   - Drivers for ARM's SCPI (System Control Processor).  Not to be
     confused with PSCI (Power State Coordination Interface).  SCPI is
     used to communicate with the assistant embedded cores doing power
     management, and we have yet to see how many of them will implement
     this for their hardware vs abstracting in other ways (or not at all
     like in the past).

   - To make confusion between SCPI and PSCI more likely, this release
     also includes an update of PSCI to interface version 1.0.

   - Rockchip support for power domains.

   - A driver to talk to the firmware on Raspberry Pi"

* tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (57 commits)
  soc: qcom: smd-rpm: Correct size of outgoing message
  bus: sunxi-rsb: Add driver for Allwinner Reduced Serial Bus
  bus: sunxi-rsb: Add Allwinner Reduced Serial Bus (RSB) controller bindings
  ARM: bcm2835: add mutual inclusion protection
  drivers: psci: make PSCI 1.0 functions initialization version dependent
  dt-bindings: Correct paths in Rockchip power domains binding document
  soc: rockchip: power-domain: don't try to print the clock name in error case
  soc: qcom/smem: add HWSPINLOCK dependency
  clk: berlin: add cpuclk
  ARM: berlin: dts: add CLKID_CPU for BG2Q
  ARM: bcm2835: Add the Raspberry Pi firmware driver
  soc: qcom: smem: Move RPM message ram out of smem DT node
  soc: qcom: smd-rpm: Correct the active vs sleep state flagging
  soc: qcom: smd: delete unneeded of_node_put
  firmware: qcom-scm: build for correct architecture level
  soc: qcom: smd: Correct SMEM items for upper channels
  qcom-scm: add missing prototype for qcom_scm_is_available()
  qcom-scm: fix endianess issue in __qcom_scm_is_call_available
  soc: qcom: smd: Reject send of too big packets
  soc: qcom: smd: Handle big endian CPUs
  ...