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cpufreq: amd-pstate: Add ->fast_switch() callback

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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: 1d215f0319 ("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>
This commit is contained in:
Gautham R. Shenoy 2023-05-17 16:28:15 +00:00 committed by Rafael J. Wysocki
parent 44c026a73b
commit 4badf2eb1e
1 changed files with 30 additions and 6 deletions
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36
drivers/cpufreq/amd-pstate.c
View file

@ -444,9 +444,8 @@ 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;
@ -465,14 +464,37 @@ 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);
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, false, policy->governor->flags);
cpufreq_freq_transition_end(policy, &freqs, false);
max_perf, fast_switch, policy->governor->flags);
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,
@ -715,6 +737,7 @@ 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;
@ -1309,6 +1332,7 @@ 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,