kernel/linux.git/drivers/cpuidle, branch v5.9.12

cpuidle: tegra: Annotate tegra_pm_set_cpu_in_lp2() with RCU_NONIDLE

2020-12-02T07:51:50+00:00

[ Upstream commit c39de538a06e76d89b7e598a71e16688009cd56c ] Annotate tegra_pm_set[clear]_cpu_in_lp2() with RCU_NONIDLE in order to fix lockdep warning about suspicious RCU usage of a spinlock during late idling phase. WARNING: suspicious RCU usage ... include/trace/events/lock.h:13 suspicious rcu_dereference_check() usage! ... (dump_stack) from (lock_acquire) (lock_acquire) from (_raw_spin_lock) (_raw_spin_lock) from (tegra_pm_set_cpu_in_lp2) (tegra_pm_set_cpu_in_lp2) from (tegra_cpuidle_enter) (tegra_cpuidle_enter) from (cpuidle_enter_state) (cpuidle_enter_state) from (cpuidle_enter_state_coupled) (cpuidle_enter_state_coupled) from (cpuidle_enter) (cpuidle_enter) from (do_idle) ... Tested-by: Peter Geis Reported-by: Peter Geis Signed-off-by: Dmitry Osipenko Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

cpuidle: tegra: Correctly handle result of arm_cpuidle_simple_enter()

2020-11-05T10:51:22+00:00

[ Upstream commit 1170433e6611402b869c583fa1fbfd85106ff066 ] The enter() callback of CPUIDLE drivers returns index of the entered idle state on success or a negative value on failure. The negative value could any negative value, i.e. it doesn't necessarily needs to be a error code. That's because CPUIDLE core only cares about the fact of failure and not about the reason of the enter() failure. Like every other enter() callback, the arm_cpuidle_simple_enter() returns the entered idle-index on success. Unlike some of other drivers, it never fails. It happened that TEGRA_C1=index=err=0 in the code of cpuidle-tegra driver, and thus, there is no problem for the cpuidle-tegra driver created by the typo in the code which assumes that the arm_cpuidle_simple_enter() returns a error code. The arm_cpuidle_simple_enter() also may return a -ENODEV error if CPU_IDLE is disabled in a kernel's config, but all CPUIDLE drivers are disabled if CPU_IDLE is disabled, including the cpuidle-tegra driver. So we can't ever see the error code from arm_cpuidle_simple_enter() today. Of course the code may get some changes in the future and then the typo may transform into a real bug, so let's correct the typo! The tegra_cpuidle_state_enter() is now changed to make it return the entered idle-index on success and negative error code on fail, which puts it on par with the arm_cpuidle_simple_enter(), making code consistent in regards to the error handling. This patch fixes a minor typo in the code, it doesn't fix any bugs. Signed-off-by: Dmitry Osipenko Reviewed-by: Jon Hunter Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

cpuidle: Drop misleading comments about RCU usage

2020-09-22T17:32:03+00:00

The commit 1098582a0f6c ("sched,idle,rcu: Push rcu_idle deeper into the idle path"), moved the calls rcu_idle_enter|exit() into the cpuidle core. However, it forgot to remove a couple of comments in enter_s2idle_proper() about why RCU_NONIDLE earlier was needed. So, let's drop them as they have become a bit misleading. Fixes: 1098582a0f6c ("sched,idle,rcu: Push rcu_idle deeper into the idle path") Signed-off-by: Ulf Hansson Signed-off-by: Rafael J. Wysocki

cpuidle: psci: Fix suspicious RCU usage

2020-09-21T13:56:53+00:00

The commit eb1f00237aca ("lockdep,trace: Expose tracepoints"), started to expose us for tracepoints. This lead to the following RCU splat on an ARM64 Qcom board. [ 5.529634] WARNING: suspicious RCU usage [ 5.537307] sdhci-pltfm: SDHCI platform and OF driver helper [ 5.541092] 5.9.0-rc3 #86 Not tainted [ 5.541098] ----------------------------- [ 5.541105] ../include/trace/events/lock.h:37 suspicious rcu_dereference_check() usage! [ 5.541110] [ 5.541110] other info that might help us debug this: [ 5.541110] [ 5.541116] [ 5.541116] rcu_scheduler_active = 2, debug_locks = 1 [ 5.541122] RCU used illegally from extended quiescent state! [ 5.541129] no locks held by swapper/0/0. [ 5.541134] [ 5.541134] stack backtrace: [ 5.541143] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.9.0-rc3 #86 [ 5.541149] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT) [ 5.541157] Call trace: [ 5.568185] sdhci_msm 7864900.sdhci: Got CD GPIO [ 5.574186] dump_backtrace+0x0/0x1c8 [ 5.574206] show_stack+0x14/0x20 [ 5.574229] dump_stack+0xe8/0x154 [ 5.574250] lockdep_rcu_suspicious+0xd4/0xf8 [ 5.574269] lock_acquire+0x3f0/0x460 [ 5.574292] _raw_spin_lock_irqsave+0x80/0xb0 [ 5.574314] __pm_runtime_suspend+0x4c/0x188 [ 5.574341] psci_enter_domain_idle_state+0x40/0xa0 [ 5.574362] cpuidle_enter_state+0xc0/0x610 [ 5.646487] cpuidle_enter+0x38/0x50 [ 5.650651] call_cpuidle+0x18/0x40 [ 5.654467] do_idle+0x228/0x278 [ 5.657678] cpu_startup_entry+0x24/0x70 [ 5.661153] rest_init+0x1a4/0x278 [ 5.665061] arch_call_rest_init+0xc/0x14 [ 5.668272] start_kernel+0x508/0x540 Following the path in pm_runtime_put_sync_suspend() from psci_enter_domain_idle_state(), it seems like we end up using the RCU. Therefore, let's simply silence the splat by informing the RCU about it with RCU_NONIDLE. Note that, this is a temporary solution. Instead we should strive to avoid using RCU_NONIDLE (and similar), but rather push rcu_idle_enter|exit() further down, closer to the arch specific code. However, as the CPU PM notifiers are also using the RCU, additional rework is needed. Reported-by: Naresh Kamboju Signed-off-by: Ulf Hansson Acked-by: Paul E. McKenney Signed-off-by: Rafael J. Wysocki

Merge tag 'powerpc-5.9-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2020-09-18T18:48:25+00:00

Pull powerpc fixes from Michael Ellerman: "Some more powerpc fixes for 5.9: - Opt us out of the DEBUG_VM_PGTABLE support for now as it's causing crashes. - Fix a long standing bug in our DMA mask handling that was hidden until recently, and which caused problems with some drivers. - Fix a boot failure on systems with large amounts of RAM, and no hugepage support and using Radix MMU, only seen in the lab. - A few other minor fixes. Thanks to Alexey Kardashevskiy, Aneesh Kumar K.V, Gautham R. Shenoy, Hari Bathini, Ira Weiny, Nick Desaulniers, Shirisha Ganta, Vaibhav Jain, and Vaidyanathan Srinivasan" * tag 'powerpc-5.9-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/papr_scm: Limit the readability of 'perf_stats' sysfs attribute cpuidle: pseries: Fix CEDE latency conversion from tb to us powerpc/dma: Fix dma_map_ops::get_required_mask Revert "powerpc/build: vdso linker warning for orphan sections" powerpc/mm: Remove DEBUG_VM_PGTABLE support on powerpc selftests/powerpc: Skip PROT_SAO test in guests/LPARS powerpc/book3s64/radix: Fix boot failure with large amount of guest memory

cpuidle: Allow cpuidle drivers to take over RCU-idle

2020-09-16T17:36:26+00:00

Some drivers have to do significant work, some of which relies on RCU still being active. Instead of using RCU_NONIDLE in the drivers and flipping RCU back on, allow drivers to take over RCU-idle duty. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Ulf Hansson Tested-by: Borislav Petkov Signed-off-by: Rafael J. Wysocki

cpuidle: pseries: Fix CEDE latency conversion from tb to us

2020-09-08T07:14:42+00:00

Commit d947fb4c965c ("cpuidle: pseries: Fixup exit latency for CEDE(0)") sets the exit latency of CEDE(0) based on the latency values of the Extended CEDE states advertised by the platform. The values advertised by the platform are in timebase ticks. However the cpuidle framework requires the latency values in microseconds. If the tb-ticks value advertised by the platform correspond to a value smaller than 1us, during the conversion from tb-ticks to microseconds, in the current code, the result becomes zero. This is incorrect as it puts a CEDE state on par with the snooze state. This patch fixes this by rounding up the result obtained while converting the latency value from tb-ticks to microseconds. It also prints a warning in case we discover an extended-cede state with wakeup latency to be 0. In such a case, ensure that CEDE(0) has a non-zero wakeup latency. Fixes: d947fb4c965c ("cpuidle: pseries: Fixup exit latency for CEDE(0)") Signed-off-by: Gautham R. Shenoy Reviewed-by: Vaidyanathan Srinivasan Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1599125247-28488-1-git-send-email-ego@linux.vnet.ibm.com

cpuidle: Make CPUIDLE_FLAG_TLB_FLUSHED generic

2020-08-26T10:41:53+00:00

This allows moving the leave_mm() call into generic code before rcu_idle_enter(). Gets rid of more trace_*_rcuidle() users. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Thomas Gleixner Acked-by: Rafael J. Wysocki Tested-by: Marco Elver Link: https://lkml.kernel.org/r/20200821085348.369441600@infradead.org

sched,idle,rcu: Push rcu_idle deeper into the idle path

2020-08-26T10:41:53+00:00

Lots of things take locks, due to a wee bug, rcu_lockdep didn't notice that the locking tracepoints were using RCU. Push rcu_idle_{enter,exit}() as deep as possible into the idle paths, this also resolves a lot of _rcuidle()/RCU_NONIDLE() usage. Specifically, sched_clock_idle_wakeup_event() will use ktime which will use seqlocks which will tickle lockdep, and stop_critical_timings() uses lock. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Thomas Gleixner Acked-by: Rafael J. Wysocki Tested-by: Marco Elver Link: https://lkml.kernel.org/r/20200821085348.310943801@infradead.org

cpuidle: Fixup IRQ state

2020-08-26T10:41:53+00:00

Match the pattern elsewhere in this file. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Thomas Gleixner Acked-by: Rafael J. Wysocki Tested-by: Marco Elver Link: https://lkml.kernel.org/r/20200821085348.251340558@infradead.org