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Commit 78e8eb8f authored by Nishanth Menon's avatar Nishanth Menon Committed by Rafael J. Wysocki
Browse files

cpufreq: cpufreq-cpu0: use RCU locks around usage of OPP 



OPP pointer is RCU protected, hence after finding it, de-reference
also should be protected with the same RCU context else the OPP
pointer may become invalid.

Reported-by: default avatarJack Mitchell <jack@embed.me.uk>
Tested-by: default avatarAlexander Holler <holler@ahsoftware.de>
Tested-by: default avatarJack Mitchell <jack@embed.me.uk>
Acked-by: default avatarAlexander Holler <holler@ahsoftware.de>
Signed-off-by: default avatarNishanth Menon <nm@ti.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent f44d188a

drivers/cpufreq/cpufreq-cpu0.c

+5 −0
Original line number Diff line number Diff line
@@ -71,12 +71,15 @@ static int cpu0_set_target(struct cpufreq_policy *policy, 
	}



	if (cpu_reg) {

		rcu_read_lock();

		opp = opp_find_freq_ceil(cpu_dev, &freq_Hz);

		if (IS_ERR(opp)) {

			rcu_read_unlock();

			pr_err("failed to find OPP for %ld\n", freq_Hz);

			return PTR_ERR(opp);

		}

		volt = opp_get_voltage(opp);

		rcu_read_unlock();

		tol = volt * voltage_tolerance / 100;

		volt_old = regulator_get_voltage(cpu_reg);

	}
@@ -236,12 +239,14 @@ static int cpu0_cpufreq_driver_init(void) 
		 */

		for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)

			;

		rcu_read_lock();

		opp = opp_find_freq_exact(cpu_dev,

				freq_table[0].frequency * 1000, true);

		min_uV = opp_get_voltage(opp);

		opp = opp_find_freq_exact(cpu_dev,

				freq_table[i-1].frequency * 1000, true);

		max_uV = opp_get_voltage(opp);

		rcu_read_unlock();

		ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV);

		if (ret > 0)

			transition_latency += ret * 1000;