cpufreq/amd-pstate: Push adjust_perf vfunc init into cpu_init

From: Mario Limonciello <[email protected]>

On shared memory designs the static functions need to work before registration is done or the system can hang at bootup.

Move the registration later in amd_pstate_init() to solve this.

Fixes e238968a2087 ("cpufreq/amd-pstate: Remove the redundant amd_pstate_set_driver() call")

Reported-by Klara Modin <[email protected]>

Closes https://lore.kernel.org/linux-pm/[email protected]/#t open here

Signed-off-by Mario Limonciello <[email protected]>

---
 drivers/cpufreq/amd-pstate.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

drivers/cpufreq/amd-pstate.c +6 -6

index e480da818d6f5..f834cc8205e2a 100644
@@ -1859,12 +1859,6 @@ static int __init amd_pstate_init(void)
 		return -ENODEV;
 	}
 
-	ret = amd_pstate_register_driver(cppc_state);
-	if (ret) {
-		pr_err("failed to register with return %d\n", ret);
-		return ret;
-	}
-
 	/* capability check */
 	if (cpu_feature_enabled(X86_FEATURE_CPPC)) {
 		pr_debug("AMD CPPC MSR based functionality is supported\n");

@@ -1875,6 +1869,12 @@ static int __init amd_pstate_init(void)
 		static_call_update(amd_pstate_update_perf, shmem_update_perf);
 	}
 
+	ret = amd_pstate_register_driver(cppc_state);
+	if (ret) {
+		pr_err("failed to register with return %d\n", ret);
+		return ret;
+	}
+
 	if (amd_pstate_prefcore) {
 		ret = amd_detect_prefcore(&amd_pstate_prefcore);
 		if (ret)

From: Mario Limonciello <[email protected]>

As the driver can be changed in and out of different modes it's possible that adjust_perf is assigned when it shouldn't be.

This could happen if an MSR design is started up in passive mode and then switches to active mode.

To solve this explicitly clear adjust_perf in amd_pstate_epp_cpu_init().

Signed-off-by Mario Limonciello <[email protected]>

---
Cc: Klara Modin <[email protected]>

  drivers/cpufreq/amd-pstate.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

drivers/cpufreq/amd-pstate.c +2 -0

index 206725219d8c9..e480da818d6f5 100644
@@ -1504,6 +1504,8 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
  		WRITE_ONCE(cpudata->cppc_cap1_cached, value);
  	}
 
+	current_pstate_driver->adjust_perf = NULL;
+
  	return 0;
 
  free_cpudata1:

From: Mario Limonciello <[email protected]>

As the driver can be changed in and out of different modes it's possible that adjust_perf is assigned when it shouldn't be.

This could happen if an MSR design is started up in passive mode and then switches to active mode.

To solve this explicitly clear adjust_perf in amd_pstate_epp_cpu_init().

Signed-off-by Mario Limonciello <[email protected]>

---
Cc: Klara Modin <[email protected]>

 drivers/cpufreq/amd-pstate.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

drivers/cpufreq/amd-pstate.c +2 -2

index 206725219d8c9..e480da818d6f5 100644
@@ -1504,6 +1504,8 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
 		WRITE_ONCE(cpudata->cppc_cap1_cached, value);
 	}
 
+	current_pstate_driver->adjust_perf = NULL;
+
 	return 0;
 
 free_cpudata1:

@@ -1866,8 +1868,6 @@ static int __init amd_pstate_init(void)
 	/* capability check */
 	if (cpu_feature_enabled(X86_FEATURE_CPPC)) {
 		pr_debug("AMD CPPC MSR based functionality is supported\n");
-		if (cppc_state != AMD_PSTATE_ACTIVE)
-			current_pstate_driver->adjust_perf = amd_pstate_adjust_perf;
 	} else {
 		pr_debug("AMD CPPC shared memory based functionality is supported\n");
 		static_call_update(amd_pstate_cppc_enable, shmem_cppc_enable);