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Wysocki" , Viresh Kumar , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen Cc: linux-pm@vger.kernel.org, x86@kernel.org, "H. Peter Anvin" , linux-rt-users@vger.kernel.org, xiao sheng wen Subject: [PATCH] cpufreq: intel_pstate: Make hwp_notify_lock a raw spinlock Date: Thu, 19 Sep 2024 10:11:21 +0200 Message-ID: <20240919081121.10784-2-ukleinek@debian.org> X-Mailer: git-send-email 2.45.2 Precedence: bulk X-Mailing-List: linux-rt-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3401; i=ukleinek@debian.org; h=from:subject; bh=AufR2rC810Q4YjbnIq0502kZyRC7aU9Fu0Tte+Po0X8=; b=owEBbQGS/pANAwAKAY+A+1h9Ev5OAcsmYgBm69yp8uS182CL8KAYt+yDqMzeLt/dhwoj+m2O9 bazfmXoTsyJATMEAAEKAB0WIQQ/gaxpOnoeWYmt/tOPgPtYfRL+TgUCZuvcqQAKCRCPgPtYfRL+ TqW0CACJwbFamuKiP+ypB3yZbzct/y5pE5qttG5mi/bDPi51UU/NlBWR51cofnPFX9lWJFBjccn JvjQkeHvT8A31EpsZ0K13h7ZCQywqRf2BAiy/olKI4D2Wflp7NuLh3gS0mZBgEKfwU9SErA1mEu sUOlYybUXenbgLpbQRC83S5jlwagUxAHc+AybmdP28DEfsH367xDI6LUX4UAB3ELoMWqzXy7FMr lfHqOcDZFBMiBymY3I3b4AEaNzgL5TezPMTI+HEq+f+RAZtmRg/93pfQwFlKmGWGUDvyMGLWMtr EibPvWgHL+dbJkRfDGorurzfTBaB+nWN91r/QrQW88eim2mB X-Developer-Key: i=ukleinek@debian.org; a=openpgp; fpr=0D2511F322BFAB1C1580266BE2DCDD9132669BD6 notify_hwp_interrupt() is called via sysvec_thermal() -> smp_thermal_vector() -> intel_thermal_interrupt() in hard irq context. For this reason it must not use a simple spin_lock that sleeps with PREEMPT_RT enabled. So convert it to a raw spinlock. Reported-by: xiao sheng wen Link: https://bugs.debian.org/1076483 Signed-off-by: Uwe Kleine-König Acked-by: Sebastian Andrzej Siewior Tested-by: xiao sheng wen --- Hello, this is deep in x86 land where I have *very* little experience and knowledge. Is sysvec_thermal() (defined in arch/x86/kernel/irq.c) really running in hard irq context? The stacktrace in the Debian bug report suggests that. So please double check my reasoning before applying this patch. Thanks Uwe drivers/cpufreq/intel_pstate.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) base-commit: 3621a2c9142bd490af0666c0c02d52d60ce0d2a5 diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index aaea9a39eced..b0018f371ea3 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -1845,7 +1845,7 @@ static void intel_pstate_notify_work(struct work_struct *work) wrmsrl_on_cpu(cpudata->cpu, MSR_HWP_STATUS, 0); } -static DEFINE_SPINLOCK(hwp_notify_lock); +static DEFINE_RAW_SPINLOCK(hwp_notify_lock); static cpumask_t hwp_intr_enable_mask; #define HWP_GUARANTEED_PERF_CHANGE_STATUS BIT(0) @@ -1868,7 +1868,7 @@ void notify_hwp_interrupt(void) if (!(value & status_mask)) return; - spin_lock_irqsave(&hwp_notify_lock, flags); + raw_spin_lock_irqsave(&hwp_notify_lock, flags); if (!cpumask_test_cpu(this_cpu, &hwp_intr_enable_mask)) goto ack_intr; @@ -1876,13 +1876,13 @@ void notify_hwp_interrupt(void) schedule_delayed_work(&all_cpu_data[this_cpu]->hwp_notify_work, msecs_to_jiffies(10)); - spin_unlock_irqrestore(&hwp_notify_lock, flags); + raw_spin_unlock_irqrestore(&hwp_notify_lock, flags); return; ack_intr: wrmsrl_safe(MSR_HWP_STATUS, 0); - spin_unlock_irqrestore(&hwp_notify_lock, flags); + raw_spin_unlock_irqrestore(&hwp_notify_lock, flags); } static void intel_pstate_disable_hwp_interrupt(struct cpudata *cpudata) @@ -1895,9 +1895,9 @@ static void intel_pstate_disable_hwp_interrupt(struct cpudata *cpudata) /* wrmsrl_on_cpu has to be outside spinlock as this can result in IPC */ wrmsrl_on_cpu(cpudata->cpu, MSR_HWP_INTERRUPT, 0x00); - spin_lock_irq(&hwp_notify_lock); + raw_spin_lock_irq(&hwp_notify_lock); cancel_work = cpumask_test_and_clear_cpu(cpudata->cpu, &hwp_intr_enable_mask); - spin_unlock_irq(&hwp_notify_lock); + raw_spin_unlock_irq(&hwp_notify_lock); if (cancel_work) cancel_delayed_work_sync(&cpudata->hwp_notify_work); @@ -1912,10 +1912,10 @@ static void intel_pstate_enable_hwp_interrupt(struct cpudata *cpudata) if (boot_cpu_has(X86_FEATURE_HWP_NOTIFY)) { u64 interrupt_mask = HWP_GUARANTEED_PERF_CHANGE_REQ; - spin_lock_irq(&hwp_notify_lock); + raw_spin_lock_irq(&hwp_notify_lock); INIT_DELAYED_WORK(&cpudata->hwp_notify_work, intel_pstate_notify_work); cpumask_set_cpu(cpudata->cpu, &hwp_intr_enable_mask); - spin_unlock_irq(&hwp_notify_lock); + raw_spin_unlock_irq(&hwp_notify_lock); if (cpu_feature_enabled(X86_FEATURE_HWP_HIGHEST_PERF_CHANGE)) interrupt_mask |= HWP_HIGHEST_PERF_CHANGE_REQ;