From: "Gautham R. Shenoy" gautham.shenoy@amd.com
[ Upstream commit 4badf2eb1e986bdbf34dd2f5d4c979553a86fe54 ]
Schedutil normally calls the adjust_perf callback for drivers with adjust_perf callback available and fast_switch_possible flag set. However, when frequency invariance is disabled and schedutil tries to invoke fast_switch. So, there is a chance of kernel crash if this function pointer is not set. To protect against this scenario add fast_switch callback to amd_pstate driver.
Fixes: 1d215f0319c2 ("cpufreq: amd-pstate: Add fast switch function for AMD P-State") Signed-off-by: Gautham R. Shenoy gautham.shenoy@amd.com Signed-off-by: Wyes Karny wyes.karny@amd.com Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com (cherry picked from commit 4badf2eb1e986bdbf34dd2f5d4c979553a86fe54) --- drivers/cpufreq/amd-pstate.c | 37 +++++++++++++++++++++++++++++------- 1 file changed, 30 insertions(+), 7 deletions(-)
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index c17bd845f5fc..446edc0fd192 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -249,9 +249,8 @@ static int amd_pstate_verify(struct cpufreq_policy_data *policy) return 0; }
-static int amd_pstate_target(struct cpufreq_policy *policy, - unsigned int target_freq, - unsigned int relation) +static int amd_pstate_update_freq(struct cpufreq_policy *policy, + unsigned int target_freq, bool fast_switch) { struct cpufreq_freqs freqs; struct amd_cpudata *cpudata = policy->driver_data; @@ -270,14 +269,36 @@ static int amd_pstate_target(struct cpufreq_policy *policy, des_perf = DIV_ROUND_CLOSEST(target_freq * cap_perf, cpudata->max_freq);
- cpufreq_freq_transition_begin(policy, &freqs); - amd_pstate_update(cpudata, min_perf, des_perf, - max_perf, false); - cpufreq_freq_transition_end(policy, &freqs, false); + WARN_ON(fast_switch && !policy->fast_switch_enabled); + /* + * If fast_switch is desired, then there aren't any registered + * transition notifiers. See comment for + * cpufreq_enable_fast_switch(). + */ + if (!fast_switch) + cpufreq_freq_transition_begin(policy, &freqs); + + amd_pstate_update(cpudata, min_perf, des_perf, max_perf, fast_switch); + + if (!fast_switch) + cpufreq_freq_transition_end(policy, &freqs, false);
return 0; }
+static int amd_pstate_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + return amd_pstate_update_freq(policy, target_freq, false); +} + +static unsigned int amd_pstate_fast_switch(struct cpufreq_policy *policy, + unsigned int target_freq) +{ + return amd_pstate_update_freq(policy, target_freq, true); +} + static void amd_pstate_adjust_perf(unsigned int cpu, unsigned long _min_perf, unsigned long target_perf, @@ -517,6 +538,7 @@ static int amd_pstate_cpu_exit(struct cpufreq_policy *policy)
freq_qos_remove_request(&cpudata->req[1]); freq_qos_remove_request(&cpudata->req[0]); + policy->fast_switch_possible = false; kfree(cpudata);
return 0; @@ -608,6 +630,7 @@ static struct cpufreq_driver amd_pstate_driver = { .flags = CPUFREQ_CONST_LOOPS | CPUFREQ_NEED_UPDATE_LIMITS, .verify = amd_pstate_verify, .target = amd_pstate_target, + .fast_switch = amd_pstate_fast_switch, .init = amd_pstate_cpu_init, .exit = amd_pstate_cpu_exit, .suspend = amd_pstate_cpu_suspend,