kernel/linux.git/drivers/rtc/rtc-cmos.c, branch v4.14.286

rtc: cmos: take rtc_lock while reading from CMOS

2022-01-27T08:00:47+00:00

commit 454f47ff464325223129b9b5b8d0b61946ec704d upstream. Reading from the CMOS involves writing to the index register and then reading from the data register. Therefore access to the CMOS has to be serialized with rtc_lock. This invocation of CMOS_READ was not serialized, which could cause trouble when other code is accessing CMOS at the same time. Use spin_lock_irq() like the rest of the function. Nothing in kernel modifies the RTC_DM_BINARY bit, so there could be a separate pair of spin_lock_irq() / spin_unlock_irq() before doing the math. Signed-off-by: Mateusz Jończyk Reviewed-by: Nobuhiro Iwamatsu Cc: Alessandro Zummo Cc: Alexandre Belloni Cc: stable@vger.kernel.org Signed-off-by: Alexandre Belloni Link: https://lore.kernel.org/r/20211210200131.153887-2-mat.jonczyk@o2.pl Signed-off-by: Greg Kroah-Hartman

rtc: cmos: Stop using shared IRQ

2020-02-14T21:32:22+00:00

commit b6da197a2e9670df6f07e6698629e9ce95ab614e upstream. As reported by Guilherme G. Piccoli: ---8<---8<---8<--- The rtc-cmos interrupt setting was changed in the commit 079062b28fb4 ("rtc: cmos: prevent kernel warning on IRQ flags mismatch") in order to allow shared interrupts; according to that commit's description, some machine got kernel warnings due to the interrupt line being shared between rtc-cmos and other hardware, and rtc-cmos didn't allow IRQ sharing that time. After the aforementioned commit though it was observed a huge increase in lost HPET interrupts in some systems, observed through the following kernel message: [...] hpet1: lost 35 rtc interrupts After investigation, it was narrowed down to the shared interrupts usage when having the kernel option "irqpoll" enabled. In this case, all IRQ handlers are called for non-timer interrupts, if such handlers are setup in shared IRQ lines. The rtc-cmos IRQ handler could be set to hpet_rtc_interrupt(), which will produce the kernel "lost interrupts" message after doing work - lots of readl/writel to HPET registers, which are known to be slow. Although "irqpoll" is not a default kernel option, it's used in some contexts, one being the kdump kernel (which is an already "impaired" kernel usually running with 1 CPU available), so the performance burden could be considerable. Also, the same issue would happen (in a shorter extent though) when using "irqfixup" kernel option. In a quick experiment, a virtual machine with uptime of 2 minutes produced >300 calls to hpet_rtc_interrupt() when "irqpoll" was set, whereas without sharing interrupts this number reduced to 1 interrupt. Machines with more hardware than a VM should generate even more unnecessary HPET interrupts in this scenario. ---8<---8<---8<--- After looking into the rtc-cmos driver history and DSDT table from the Microsoft Surface 3, we may notice that Hans de Goede submitted a correct fix (see dependency below). Thus, we simply revert the culprit commit. Fixes: 079062b28fb4 ("rtc: cmos: prevent kernel warning on IRQ flags mismatch") Depends-on: a1e23a42f1bd ("rtc: cmos: Do not assume irq 8 for rtc when there are no legacy irqs") Reported-by: Guilherme G. Piccoli Cc: Hans de Goede Signed-off-by: Andy Shevchenko Tested-by: Guilherme G. Piccoli Reviewed-by: Hans de Goede Link: https://lore.kernel.org/r/20200123131437.28157-1-andriy.shevchenko@linux.intel.com Signed-off-by: Alexandre Belloni Signed-off-by: Greg Kroah-Hartman

Merge branches 'pm-sleep' and 'powercap'

2017-05-22T18:32:05+00:00

* pm-sleep: PM / hibernate: Declare variables as static RTC: rtc-cmos: Fix wakeup from suspend-to-idle PM / wakeup: Fix up wakeup_source_report_event() * powercap: PowerCap: Fix an error code in powercap_register_zone()

RTC: rtc-cmos: Fix wakeup from suspend-to-idle

2017-05-14T00:23:12+00:00

Commit eed4d47efe95 (ACPI / sleep: Ignore spurious SCI wakeups from suspend-to-idle) modified the core suspend-to-idle code to filter out spurious SCI interrupts received while suspended, which requires ACPI event source handlers to report wakeup events in a way that will trigger a wakeup from suspend to idle (or abort system suspends in progress, which is equivalent). That needs to be done in the rtc-cmos driver too, which was overlooked by the above commit, so do that now. Fixes: eed4d47efe95 (ACPI / sleep: Ignore spurious SCI wakeups from suspend-to-idle) Reported-by: David E. Box Signed-off-by: Rafael J. Wysocki

rtc: cmos: Do not assume irq 8 for rtc when there are no legacy irqs

2017-04-14T10:08:51+00:00

On some systems (e.g. Intel Bay Trail systems) the legacy PIC is not used, in this case virq 8 will be a random irq, rather then hw_irq 8 from the PIC. Requesting virq 8 in this case will not help us to get alarm irqs and may cause problems for other drivers which actually do need virq 8, for example on an Asus Transformer T100TA this leads to: [ 28.745155] genirq: Flags mismatch irq 8. 00000088 (mmc0) vs. 00000080 (rtc0) [ 28.753700] mmc0: Failed to request IRQ 8: -16 [ 28.975934] sdhci-acpi: probe of 80860F14:01 failed with error -16 This commit fixes this by making the rtc-cmos driver continue without using an irq rather then claiming irq 8 when no irq is specified in the pnp-info and there are no legacy-irqs. Signed-off-by: Hans de Goede Signed-off-by: Alexandre Belloni

Merge tag 'rtc-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux

2016-12-19T02:18:03+00:00

Pull RTC updates from Alexandre Belloni: "Subsystem: - non-modular drivers are now explicitly non-modular New driver: - Epson Toyocom rtc-7301sf/dg Drivers: - cmos: reject unsupported alarm values wrt the RTC capabilities - ds1307: ACPI support - jz4740: DT support, jz4780 handling, can now be used as a system power controller - mcp795: many fixes, in particular proper month handling - twl: driver is now DT only" * tag 'rtc-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (31 commits) rtc: mcp795: Fix whitespace and indentation. rtc: mcp795: Prefer using the BIT() macro. rtc: mcp795: fix month write resetting date to 1. rtc: mcp795: fix time range difference between linux and RTC chip. rtc: mcp795: fix bitmask value for leap year (LP). rtc: mcp795: use bcd2bin/bin2bcd. rtc: add support for EPSON TOYOCOM RTC-7301SF/DG rtc: ds1307: Add ACPI support rtc: imxdi: (trivial) fix a typo rtc: ds1374: Merge conditional + WARN_ON() rtc: twl: make driver DT only rtc: twl: kill static variables rtc: fix typos in Kconfig rtc: jz4740: make the driver builtin only rtc: jz4740: remove unused EXPORT_SYMBOL Documentation: bindings: fix twl-rtc documentation rtc: Enable compile testing for Maxim and Samsung drivers MIPS: jz4740: Remove obsolete code MIPS: qi_lb60: Probe RTC driver from DT and use it as power controller MIPS: jz4740: DTS: Probe the jz4740-rtc driver from devicetree ...

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

2016-12-13T03:56:15+00:00

Pull timer updates from Thomas Gleixner: "The time/timekeeping/timer folks deliver with this update: - Fix a reintroduced signed/unsigned issue and cleanup the whole signed/unsigned mess in the timekeeping core so this wont happen accidentaly again. - Add a new trace clock based on boot time - Prevent injection of random sleep times when PM tracing abuses the RTC for storage - Make posix timers configurable for real tiny systems - Add tracepoints for the alarm timer subsystem so timer based suspend wakeups can be instrumented - The usual pile of fixes and updates to core and drivers" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) timekeeping: Use mul_u64_u32_shr() instead of open coding it timekeeping: Get rid of pointless typecasts timekeeping: Make the conversion call chain consistently unsigned timekeeping_Force_unsigned_clocksource_to_nanoseconds_conversion alarmtimer: Add tracepoints for alarm timers trace: Update documentation for mono, mono_raw and boot clock trace: Add an option for boot clock as trace clock timekeeping: Add a fast and NMI safe boot clock timekeeping/clocksource_cyc2ns: Document intended range limitation timekeeping: Ignore the bogus sleep time if pm_trace is enabled selftests/timers: Fix spelling mistake "Asyncrhonous" -> "Asynchronous" clocksource/drivers/bcm2835_timer: Unmap region obtained by of_iomap clocksource/drivers/arm_arch_timer: Map frame with of_io_request_and_map() arm64: dts: rockchip: Arch counter doesn't tick in system suspend clocksource/drivers/arm_arch_timer: Don't assume clock runs in suspend posix-timers: Make them configurable posix_cpu_timers: Move the add_device_randomness() call to a proper place timer: Move sys_alarm from timer.c to itimer.c ptp_clock: Allow for it to be optional Kconfig: Regenerate *.c_shipped files after previous changes ...

timekeeping: Ignore the bogus sleep time if pm_trace is enabled

2016-11-29T17:02:58+00:00

Power management suspend/resume tracing (ab)uses the RTC to store suspend/resume information persistently. As a consequence the RTC value is clobbered when timekeeping is resumed and tries to inject the sleep time. Commit a4f8f6667f09 ("timekeeping: Cap array access in timekeeping_debug") plugged a out of bounds array access in the timekeeping debug code which was caused by the clobbered RTC value, but we still use the clobbered RTC value for sleep time injection into kernel timekeeping, which will result in random adjustments depending on the stored "hash" value. To prevent this keep track of the RTC clobbering and ignore the invalid RTC timestamp at resume. If the system resumed successfully clear the flag, which marks the RTC as unusable, warn the user about the RTC clobber and recommend to adjust the RTC with 'ntpdate' or 'rdate'. [jstultz: Fixed up pr_warn formating, and implemented suggestions from Ingo] [ tglx: Rewrote changelog ] Originally-from: Thomas Gleixner Signed-off-by: Chen Yu Signed-off-by: John Stultz Acked-by: Pavel Machek Acked-by: Thomas Gleixner Cc: Prarit Bhargava Cc: "Rafael J. Wysocki" Cc: Richard Cochran Cc: Xunlei Pang Cc: Len Brown Link: http://lkml.kernel.org/r/1480372524-15181-3-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner

rtc: cmos: Don't enable interrupts in the middle of the interrupt handler

2016-10-20T15:40:06+00:00

Using spin_lock_irq()/spin_unlock_irq() from within the interrupt handler is a no-no. Let's save/restore the flags to avoid turning on interrupts prematurely. We hit this in a bunch of our CI systems, but for whatever reason I wasn't able to reproduce on my own machine, so this fix is just based on the backtrace. [ 202.634918] WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:2729 trace_hardirqs_on_caller+0x113/0x1b0 [ 202.634919] DEBUG_LOCKS_WARN_ON(current->hardirq_context) [ 202.634929] Modules linked in: snd_hda_intel i915 x86_pkg_temp_thermal intel_powerclamp coretemp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel lpc_ich snd_hda_codec_realtek snd_hda_codec_generic snd_hda_codec_hdmi snd_hda_codec snd_hwdep i2c_designware_platform i2c_designware_core snd_hda_core mei_me mei snd_pcm r8169 mii sdhci_acpi sdhci mmc_core i2c_hid [last unloaded: i915] [ 202.634930] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G U 4.9.0-rc1-CI-CI_DRM_1734+ #1 [ 202.634931] Hardware name: GIGABYTE M4HM87P-00/M4HM87P-00, BIOS F6 12/10/2014 [ 202.634933] ffff88011ea03d68 ffffffff8142dce5 ffff88011ea03db8 0000000000000000 [ 202.634934] ffff88011ea03da8 ffffffff8107e496 00000aa900000002 ffffffff81e249a0 [ 202.634935] ffffffff81815637 ffffffff82e7c280 0000000000000000 0000000000000004 [ 202.634936] Call Trace: [ 202.634939] [ 202.634939] [] dump_stack+0x67/0x92 [ 202.634941] [] __warn+0xc6/0xe0 [ 202.634944] [] ? _raw_spin_unlock_irq+0x27/0x50 [ 202.634945] [] warn_slowpath_fmt+0x4a/0x50 [ 202.634946] [] trace_hardirqs_on_caller+0x113/0x1b0 [ 202.634948] [] trace_hardirqs_on+0xd/0x10 [ 202.634949] [] _raw_spin_unlock_irq+0x27/0x50 [ 202.634951] [] rtc_handler+0x32/0xa0 [ 202.634954] [] acpi_ev_fixed_event_detect+0xd4/0xfb [ 202.634956] [] acpi_ev_sci_xrupt_handler+0xf/0x2d [ 202.634957] [] acpi_irq+0x11/0x2c [ 202.634960] [] __handle_irq_event_percpu+0x58/0x370 [ 202.634961] [] handle_irq_event_percpu+0x1e/0x50 [ 202.634962] [] handle_irq_event+0x34/0x60 [ 202.634963] [] handle_fasteoi_irq+0xa6/0x170 [ 202.634966] [] handle_irq+0x15/0x20 [ 202.634967] [] do_IRQ+0x68/0x130 [ 202.634968] [] common_interrupt+0x89/0x89 [ 202.634970] [ 202.634970] [] ? mwait_idle+0x93/0x210 [ 202.634971] [] ? mwait_idle+0x8a/0x210 [ 202.634972] [] arch_cpu_idle+0xa/0x10 [ 202.634973] [] default_idle_call+0x1e/0x30 [ 202.634974] [] cpu_startup_entry+0x17c/0x1f0 [ 202.634976] [] rest_init+0x127/0x130 [ 202.634978] [] start_kernel+0x3f6/0x403 [ 202.634980] [] x86_64_start_reservations+0x2a/0x2c [ 202.634981] [] x86_64_start_kernel+0x173/0x186 [ 202.634982] ---[ end trace 293c99618fa08d34 ]--- Cc: Gabriele Mazzotta Cc: Alexandre Belloni Fixes: 983bf1256edb ("rtc: cmos: Clear ACPI-driven alarms upon resume") Signed-off-by: Ville Syrjälä Reviewed-by: Chris Wilson Signed-off-by: Alexandre Belloni

rtc: cmos: don't refer to asm-generic/rtc.h

2016-10-19T07:41:48+00:00

That header has been gone for a while. I've fixed up the Kconfig comment, but the one in rtc-cmos.c doesn't make any sense to me even looking at its history. Signed-off-by: Christoph Hellwig Signed-off-by: Alexandre Belloni