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authorGautham R. Shenoy <gautham.shenoy@amd.com>2023-05-17 16:28:15 +0000
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2023-05-24 19:39:16 +0200
commit4badf2eb1e986bdbf34dd2f5d4c979553a86fe54 (patch)
treefc40941961ae5b05d2cb8f950168d3d6f16169f6 /drivers/cpufreq
parent44c026a73be8038f03dbdeef028b642880cf1511 (diff)
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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>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/amd-pstate.c36
1 files changed, 30 insertions, 6 deletions
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 5a3d4aa0f45a..45711fc0a856 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,