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| author | Gautham R. Shenoy <gautham.shenoy@amd.com> | 2023-05-17 16:28:15 +0000 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2023-05-24 19:39:16 +0200 |
| commit | 4badf2eb1e986bdbf34dd2f5d4c979553a86fe54 (patch) | |
| tree | fc40941961ae5b05d2cb8f950168d3d6f16169f6 | |
| parent | 44c026a73be8038f03dbdeef028b642880cf1511 (diff) | |
| download | linux-4badf2eb1e986bdbf34dd2f5d4c979553a86fe54.tar.gz | |
cpufreq: amd-pstate: Add ->fast_switch() callback
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>
| -rw-r--r-- | drivers/cpufreq/amd-pstate.c | 36 |
1 files changed, 30 insertions, 6 deletions
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index 5a3d4aa0f45a6..45711fc0a8565 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -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, |