From: Ionela Voinescu <ionela.voinescu@arm.com> To: catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, maz@kernel.org, suzuki.poulose@arm.com, sudeep.holla@arm.com, lukasz.luba@arm.com, valentin.schneider@arm.com, dietmar.eggemann@arm.com, rjw@rjwysocki.net, pkondeti@codeaurora.org, ionela.voinescu@arm.com Cc: peterz@infradead.org, mingo@redhat.com, vincent.guittot@linaro.org, viresh.kumar@linaro.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Subject: [PATCH v6 7/7] clocksource/drivers/arm_arch_timer: validate arch_timer_rate Date: Thu, 5 Mar 2020 09:06:27 +0000 [thread overview] Message-ID: <20200305090627.31908-8-ionela.voinescu@arm.com> (raw) In-Reply-To: <20200305090627.31908-1-ionela.voinescu@arm.com> Using an arch timer with a frequency of less than 1MHz can potentially result in incorrect functionality in systems that assume a reasonable rate of the arch timer of 1 to 50MHz, described as typical in the architecture specification. Therefore, warn if the arch timer rate is below 1MHz, which is considered atypical and worth emphasizing. Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com> Suggested-by: Valentin Schneider <valentin.schneider@arm.com> Acked-by: Marc Zyngier <maz@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Marc Zyngier <maz@kernel.org> --- drivers/clocksource/arm_arch_timer.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 9a5464c625b4..4faa930eabf8 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -885,6 +885,17 @@ static int arch_timer_starting_cpu(unsigned int cpu) return 0; } +static int validate_timer_rate(void) +{ + if (!arch_timer_rate) + return -EINVAL; + + /* Arch timer frequency < 1MHz can cause trouble */ + WARN_ON(arch_timer_rate < 1000000); + + return 0; +} + /* * For historical reasons, when probing with DT we use whichever (non-zero) * rate was probed first, and don't verify that others match. If the first node @@ -900,7 +911,7 @@ static void arch_timer_of_configure_rate(u32 rate, struct device_node *np) arch_timer_rate = rate; /* Check the timer frequency. */ - if (arch_timer_rate == 0) + if (validate_timer_rate()) pr_warn("frequency not available\n"); } @@ -1594,9 +1605,10 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table) * CNTFRQ value. This *must* be correct. */ arch_timer_rate = arch_timer_get_cntfrq(); - if (!arch_timer_rate) { + ret = validate_timer_rate(); + if (ret) { pr_err(FW_BUG "frequency not available.\n"); - return -EINVAL; + return ret; } arch_timer_uses_ppi = arch_timer_select_ppi(); -- 2.17.1
WARNING: multiple messages have this Message-ID (diff)
From: Ionela Voinescu <ionela.voinescu@arm.com> To: catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, maz@kernel.org, suzuki.poulose@arm.com, sudeep.holla@arm.com, lukasz.luba@arm.com, valentin.schneider@arm.com, dietmar.eggemann@arm.com, rjw@rjwysocki.net, pkondeti@codeaurora.org, ionela.voinescu@arm.com Cc: linux-doc@vger.kernel.org, peterz@infradead.org, viresh.kumar@linaro.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, linux-arm-kernel@lists.infradead.org Subject: [PATCH v6 7/7] clocksource/drivers/arm_arch_timer: validate arch_timer_rate Date: Thu, 5 Mar 2020 09:06:27 +0000 [thread overview] Message-ID: <20200305090627.31908-8-ionela.voinescu@arm.com> (raw) In-Reply-To: <20200305090627.31908-1-ionela.voinescu@arm.com> Using an arch timer with a frequency of less than 1MHz can potentially result in incorrect functionality in systems that assume a reasonable rate of the arch timer of 1 to 50MHz, described as typical in the architecture specification. Therefore, warn if the arch timer rate is below 1MHz, which is considered atypical and worth emphasizing. Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com> Suggested-by: Valentin Schneider <valentin.schneider@arm.com> Acked-by: Marc Zyngier <maz@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Marc Zyngier <maz@kernel.org> --- drivers/clocksource/arm_arch_timer.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 9a5464c625b4..4faa930eabf8 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -885,6 +885,17 @@ static int arch_timer_starting_cpu(unsigned int cpu) return 0; } +static int validate_timer_rate(void) +{ + if (!arch_timer_rate) + return -EINVAL; + + /* Arch timer frequency < 1MHz can cause trouble */ + WARN_ON(arch_timer_rate < 1000000); + + return 0; +} + /* * For historical reasons, when probing with DT we use whichever (non-zero) * rate was probed first, and don't verify that others match. If the first node @@ -900,7 +911,7 @@ static void arch_timer_of_configure_rate(u32 rate, struct device_node *np) arch_timer_rate = rate; /* Check the timer frequency. */ - if (arch_timer_rate == 0) + if (validate_timer_rate()) pr_warn("frequency not available\n"); } @@ -1594,9 +1605,10 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table) * CNTFRQ value. This *must* be correct. */ arch_timer_rate = arch_timer_get_cntfrq(); - if (!arch_timer_rate) { + ret = validate_timer_rate(); + if (ret) { pr_err(FW_BUG "frequency not available.\n"); - return -EINVAL; + return ret; } arch_timer_uses_ppi = arch_timer_select_ppi(); -- 2.17.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-03-05 9:07 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-03-05 9:06 [PATCH v6 0/7] arm64: ARMv8.4 Activity Monitors support Ionela Voinescu 2020-03-05 9:06 ` Ionela Voinescu 2020-03-05 9:06 ` [PATCH v6 1/7] arm64: add support for the AMU extension v1 Ionela Voinescu 2020-03-05 9:06 ` Ionela Voinescu 2020-03-05 9:06 ` [PATCH v6 2/7] arm64: trap to EL1 accesses to AMU counters from EL0 Ionela Voinescu 2020-03-05 9:06 ` Ionela Voinescu 2020-03-05 9:06 ` [PATCH v6 3/7] arm64/kvm: disable access to AMU registers from kvm guests Ionela Voinescu 2020-03-05 9:06 ` Ionela Voinescu 2020-03-05 9:06 ` [PATCH v6 4/7] Documentation: arm64: document support for the AMU extension Ionela Voinescu 2020-03-05 9:06 ` Ionela Voinescu 2020-03-05 9:06 ` [PATCH v6 5/7] cpufreq: add function to get the hardware max frequency Ionela Voinescu 2020-03-05 9:06 ` Ionela Voinescu 2020-03-05 9:06 ` [PATCH v6 6/7] arm64: use activity monitors for frequency invariance Ionela Voinescu 2020-03-05 9:06 ` Ionela Voinescu 2020-03-06 11:53 ` Sudeep Holla 2020-03-06 11:53 ` Sudeep Holla 2020-03-05 9:06 ` Ionela Voinescu [this message] 2020-03-05 9:06 ` [PATCH v6 7/7] clocksource/drivers/arm_arch_timer: validate arch_timer_rate Ionela Voinescu 2020-03-06 11:21 ` [PATCH v6 0/7] arm64: ARMv8.4 Activity Monitors support Catalin Marinas 2020-03-06 11:21 ` Catalin Marinas 2020-03-09 14:11 ` Ionela Voinescu 2020-03-09 14:11 ` Ionela Voinescu
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