kernel.git/drivers/clocksource/exynos_mct.c, branch linux-4.11.y

clocksource/exynos_mct: Clear interrupt when cpu is shut down

2017-01-17T09:08:38Z

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: stable@vger.kernel.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

Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2016-12-25T22:30:04Z

Pull timer type cleanups from Thomas Gleixner: "This series does a tree wide cleanup of types related to timers/timekeeping. - Get rid of cycles_t and use a plain u64. The type is not really helpful and caused more confusion than clarity - Get rid of the ktime union. The union has become useless as we use the scalar nanoseconds storage unconditionally now. The 32bit timespec alike storage got removed due to the Y2038 limitations some time ago. That leaves the odd union access around for no reason. Clean it up. Both changes have been done with coccinelle and a small amount of manual mopping up" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ktime: Get rid of ktime_equal() ktime: Cleanup ktime_set() usage ktime: Get rid of the union clocksource: Use a plain u64 instead of cycle_t

clocksource: Use a plain u64 instead of cycle_t

2016-12-25T10:04:12Z

There is no point in having an extra type for extra confusion. u64 is unambiguous. Conversion was done with the following coccinelle script: @rem@ @@ -typedef u64 cycle_t; @fix@ typedef cycle_t; @@ -cycle_t +u64 Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: John Stultz

cpu/hotplug: Cleanup state names

2016-12-25T09:47:44Z

When the state names got added a script was used to add the extra argument to the calls. The script basically converted the state constant to a string, but the cleanup to convert these strings into meaningful ones did not happen. Replace all the useless strings with 'subsys/xxx/yyy:state' strings which are used in all the other places already. Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: Sebastian Siewior Link: http://lkml.kernel.org/r/20161221192112.085444152@linutronix.de Signed-off-by: Thomas Gleixner

clocksource: exynos_mct: Add the support for ARM64

2016-09-16T11:07:53Z

This patch allows building and compile-testing the driver also for ARM64. The delay_timer is only supported on ARMv7. Cc: Daniel Lezcano Cc: Thomas Gleixner Cc: Kukjin Kim Cc: Krzysztof Kozlowski Signed-off-by: Chanwoo Choi Acked-by: Daniel Lezcano [k.kozlowski: Adjusted commit msg] Signed-off-by: Krzysztof Kozlowski

clocksource/exynos_mct: Convert to hotplug state machine

2016-07-15T08:41:44Z

Install the callbacks via the state machine and let the core invoke the callbacks on the already online CPUs. Signed-off-by: Richard Cochran Signed-off-by: Anna-Maria Gleixner Reviewed-by: Sebastian Andrzej Siewior Cc: Daniel Lezcano Cc: Krzysztof Kozlowski Cc: Kukjin Kim Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-samsung-soc@vger.kernel.org Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153338.147940411@linutronix.de Signed-off-by: Ingo Molnar

clocksources: Switch back to the clksrc table

2016-06-28T08:19:35Z

All the clocksource drivers's init function are now converted to return an error code. CLOCKSOURCE_OF_DECLARE is no longer used as well as the clksrc-of table. Let's convert back the names: - CLOCKSOURCE_OF_DECLARE_RET => CLOCKSOURCE_OF_DECLARE - clksrc-of-ret => clksrc-of Signed-off-by: Daniel Lezcano For exynos_mct and samsung_pwm_timer: Acked-by: Krzysztof Kozlowski For arch/arc: Acked-by: Vineet Gupta For mediatek driver: Acked-by: Matthias Brugger For the Rockchip-part Acked-by: Heiko Stuebner For STi : Acked-by: Patrice Chotard For the mps2-timer.c and versatile.c changes: Acked-by: Liviu Dudau For the OXNAS part : Acked-by: Neil Armstrong For LPC32xx driver: Acked-by: Sylvain Lemieux For Broadcom Kona timer change: Acked-by: Ray Jui For Sun4i and Sun5i: Acked-by: Chen-Yu Tsai For Meson6: Acked-by: Carlo Caione For Keystone: Acked-by: Santosh Shilimkar For NPS: Acked-by: Noam Camus For bcm2835: Acked-by: Eric Anholt

clocksource/drivers/exynos_mct: Convert init function to return error

2016-06-28T08:19:18Z

The init functions do not return any error. They behave as the following: - panic, thus leading to a kernel crash while another timer may work and make the system boot up correctly or - print an error and let the caller unaware if the state of the system Change that by converting the init functions to return an error conforming to the CLOCKSOURCE_OF_RET prototype. Proper error handling (rollback, errno value) will be changed later case by case, thus this change just return back an error or success in the init function. Signed-off-by: Daniel Lezcano Reviewed-by: Krzysztof Kozlowski

clockevents/drivers/exynos_mct: Implement ->set_state_oneshot_stopped()

2016-02-25T13:34:08Z

set_state_oneshot_stopped() is called by the clkevt core, when the next event is required at an expiry time of 'KTIME_MAX'. This normally happens with NO_HZ_{IDLE|FULL} in both LOWRES/HIGHRES modes. This patch makes the clockevent device to stop on such an event, to avoid spurious interrupts, as explained by: commit 8fff52fd5093 ("clockevents: Introduce CLOCK_EVT_STATE_ONESHOT_STOPPED state"). Signed-off-by: Viresh Kumar Signed-off-by: Daniel Lezcano

clocksource/drivers/exynos_mct: Use container_of() instead of this_cpu_ptr()

2015-10-15T15:42:03Z

Since evt structure is embedded in per-CPU mevt structure it's definitely faster to use container_of() to get access to mevt if we have evt (for example as incoming function argument) instead of more expensive approach with this_cpu_ptr(&percpu_mct_tick). this_cpu_ptr() on per-CPU mevt structure leads to access to cp15 to get cpu id and arithmetic operations. Container_of() is cheaper since it's just one asm instruction. This should work if used evt pointer is correct and owned by local mevt structure. For example, before this patch set_state_shutdown() looks like: 4a4: e92d4010 push {r4, lr} 4a8: e3004000 movw r4, #0 4ac: ebfffffe bl 0 4b0: e3003000 movw r3, #0 4b4: e3404000 movt r4, #0 4b8: e3403000 movt r3, #0 4bc: e7933100 ldr r3, [r3, r0, lsl #2] 4c0: e0844003 add r4, r4, r3 4c4: e59400c0 ldr r0, [r4, #192] ; 0xc0 4c8: ebffffd4 bl 420 4cc: e3a00000 mov r0, #0 4d0: e8bd8010 pop {r4, pc} With this patch: 4a4: e92d4010 push {r4, lr} 4a8: e59000c0 ldr r0, [r0, #192] ; 0xc0 4ac: ebffffdb bl 420 4b0: e3a00000 mov r0, #0 4b4: e8bd8010 pop {r4, pc} Also, for me size of exynos_mct.o decreased from 84588 bytes to 83956. Signed-off-by: Alexey Klimov Signed-off-by: Daniel Lezcano Reviewed-by: Krzysztof Kozlowski