From 1e24c31351787e24b7eebe84866bd55fd62a0aef Mon Sep 17 00:00:00 2001 From: Srinivas Pandruvada Date: Fri, 31 May 2024 16:00:04 -0700 Subject: cpufreq: intel_pstate: Fix unchecked HWP MSR access Fix unchecked MSR access error for processors with no HWP support. On such processors, maximum frequency can be changed by the system firmware using ACPI event ACPI_PROCESSOR_NOTIFY_HIGEST_PERF_CHANGED. This results in accessing HWP MSR 0x771. Call Trace: generic_exec_single+0x58/0x120 smp_call_function_single+0xbf/0x110 rdmsrl_on_cpu+0x46/0x60 intel_pstate_get_hwp_cap+0x1b/0x70 intel_pstate_update_limits+0x2a/0x60 acpi_processor_notify+0xb7/0x140 acpi_ev_notify_dispatch+0x3b/0x60 HWP MSR 0x771 can be only read on a CPU which supports HWP and enabled. Hence intel_pstate_get_hwp_cap() can only be called when hwp_active is true. Reported-by: Sebastian Andrzej Siewior Closes: https://lore.kernel.org/linux-pm/20240529155740.Hq2Hw7be@linutronix.de/ Fixes: e8217b4bece3 ("cpufreq: intel_pstate: Update the maximum CPU frequency consistently") Tested-by: Sebastian Andrzej Siewior Signed-off-by: Srinivas Pandruvada Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/intel_pstate.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/cpufreq') diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 4b986c044741..65d3f79104bd 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -1153,7 +1153,8 @@ static void intel_pstate_update_policies(void) static void __intel_pstate_update_max_freq(struct cpudata *cpudata, struct cpufreq_policy *policy) { - intel_pstate_get_hwp_cap(cpudata); + if (hwp_active) + intel_pstate_get_hwp_cap(cpudata); policy->cpuinfo.max_freq = READ_ONCE(global.no_turbo) ? cpudata->pstate.max_freq : cpudata->pstate.turbo_freq; -- cgit v1.2.3