From bb9b96d96f583b1953c1c190fb5f0c8a2c144b59 Mon Sep 17 00:00:00 2001 From: Alexey Klimov Date: Mon, 27 Mar 2023 13:17:36 +0000 Subject: [PATCH] UPSTREAM: cpuidle, dt: Push RCU-idle into driver Doing RCU-idle outside the driver, only to then temporarily enable it again before going idle is suboptimal. Notably: this converts all dt_init_idle_driver() and __CPU_PM_CPU_IDLE_ENTER() users for they are inextrably intertwined. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Tested-by: Tony Lindgren Tested-by: Ulf Hansson Acked-by: Rafael J. Wysocki Acked-by: Frederic Weisbecker Link: https://lore.kernel.org/r/20230112195540.068981667@infradead.org Bug: 272060410 (cherry picked from commit 0c5ffc3d7b15978c6b184938cd6b8af06e436424) [alexey: bringing back the upstream change now that the root problem for it being reverted is workarounded in exynos-cpupm driver. The issue was that one of cpu pm notifiers via cpu_pm_enter() didn't allow a CPU to transition into deeper idle state during reboot which enabled the kernel to spin in a "loop" trying to put CPU in this idle state continuously. This flow is no longer covered by ct_cpuidle_{enter,exit}() section and RCU, if required, was waiting for synchronization from these CPUs during reboot for a long time using rcu_barrier().] Signed-off-by: Alexey Klimov Change-Id: I452cc3c8779b76237b04a0afd5919d3e3d01809c --- drivers/acpi/processor_idle.c | 2 ++ drivers/cpuidle/cpuidle-big_little.c | 12 ++++++++---- drivers/cpuidle/dt_idle_states.c | 2 +- 3 files changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index c3d00e833bcf..9718d07cc2a2 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -1223,6 +1223,8 @@ static int acpi_processor_setup_lpi_states(struct acpi_processor *pr) state->target_residency = lpi->min_residency; if (lpi->arch_flags) state->flags |= CPUIDLE_FLAG_TIMER_STOP; + if (i != 0 && lpi->entry_method == ACPI_CSTATE_FFH) + state->flags |= CPUIDLE_FLAG_RCU_IDLE; state->enter = acpi_idle_lpi_enter; drv->safe_state_index = i; } diff --git a/drivers/cpuidle/cpuidle-big_little.c b/drivers/cpuidle/cpuidle-big_little.c index abe51185f243..74972deda0ea 100644 --- a/drivers/cpuidle/cpuidle-big_little.c +++ b/drivers/cpuidle/cpuidle-big_little.c @@ -64,7 +64,8 @@ static struct cpuidle_driver bl_idle_little_driver = { .enter = bl_enter_powerdown, .exit_latency = 700, .target_residency = 2500, - .flags = CPUIDLE_FLAG_TIMER_STOP, + .flags = CPUIDLE_FLAG_TIMER_STOP | + CPUIDLE_FLAG_RCU_IDLE, .name = "C1", .desc = "ARM little-cluster power down", }, @@ -85,7 +86,8 @@ static struct cpuidle_driver bl_idle_big_driver = { .enter = bl_enter_powerdown, .exit_latency = 500, .target_residency = 2000, - .flags = CPUIDLE_FLAG_TIMER_STOP, + .flags = CPUIDLE_FLAG_TIMER_STOP | + CPUIDLE_FLAG_RCU_IDLE, .name = "C1", .desc = "ARM big-cluster power down", }, @@ -120,15 +122,17 @@ static int notrace bl_powerdown_finisher(unsigned long arg) * Called from the CPUidle framework to program the device to the * specified target state selected by the governor. */ -static int bl_enter_powerdown(struct cpuidle_device *dev, - struct cpuidle_driver *drv, int idx) +static __cpuidle int bl_enter_powerdown(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int idx) { cpu_pm_enter(); + ct_cpuidle_enter(); cpu_suspend(0, bl_powerdown_finisher); /* signals the MCPM core that CPU is out of low power state */ mcpm_cpu_powered_up(); + ct_cpuidle_exit(); cpu_pm_exit(); diff --git a/drivers/cpuidle/dt_idle_states.c b/drivers/cpuidle/dt_idle_states.c index 7ca3d7d9b5ea..02aa0b39af9d 100644 --- a/drivers/cpuidle/dt_idle_states.c +++ b/drivers/cpuidle/dt_idle_states.c @@ -77,7 +77,7 @@ static int init_state_node(struct cpuidle_state *idle_state, if (err) desc = state_node->name; - idle_state->flags = 0; + idle_state->flags = CPUIDLE_FLAG_RCU_IDLE; if (of_property_read_bool(state_node, "local-timer-stop")) idle_state->flags |= CPUIDLE_FLAG_TIMER_STOP; /*