From bdc21a4d286c6917fe966fd765de99411095b1b4 Mon Sep 17 00:00:00 2001 From: Lukasz Luba Date: Mon, 21 Mar 2022 09:57:22 +0000 Subject: PM: EM: Add .get_cost() callback The Energy Model (EM) supports devices which report abstract power scale, not only real Watts. The primary goal for EM is to enable the Energy Aware Scheduler (EAS) for a given platform. Some of the platforms might not be able to deliver proper power values. The only information that they might have is the relative efficiency between CPU types. Thus, it makes sense to remove some restrictions in the EM framework and introduce a mechanism which would support those platforms. What is crucial for EAS to operate is the 'cost' field in the EM. The 'cost' is calculated internally in EM framework based on knowledge from 'power' values. The 'cost' values must be strictly increasing. The existing API with its 'power' value size restrictions cannot guarantee that the 'cost' will meet this requirement. Since the platform is missing this detailed information, but has only efficiency details, introduce a new custom callback in the EM framework. The new callback would allow to provide the 'cost' values which reflect efficiency of the CPUs. This would allow to provide EAS information which has different relation than what would be forced by the EM internal formulas calculating 'cost' values. Thanks to this new callback it is possible to create a system view for EAS which has no overlapping performance states across many Performance Domains. Signed-off-by: Lukasz Luba Reviewed-by: Ionela Voinescu Signed-off-by: Rafael J. Wysocki --- include/linux/energy_model.h | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h index 9f3c400bc52d..0a3a5663177b 100644 --- a/include/linux/energy_model.h +++ b/include/linux/energy_model.h @@ -114,9 +114,30 @@ struct em_data_callback { */ int (*active_power)(unsigned long *power, unsigned long *freq, struct device *dev); + + /** + * get_cost() - Provide the cost at the given performance state of + * a device + * @dev : Device for which we do this operation (can be a CPU) + * @freq : Frequency at the performance state in kHz + * @cost : The cost value for the performance state + * (modified) + * + * In case of CPUs, the cost is the one of a single CPU in the domain. + * It is expected to fit in the [0, EM_MAX_POWER] range due to internal + * usage in EAS calculation. + * + * Return 0 on success, or appropriate error value in case of failure. + */ + int (*get_cost)(struct device *dev, unsigned long freq, + unsigned long *cost); }; -#define EM_DATA_CB(_active_power_cb) { .active_power = &_active_power_cb } #define EM_SET_ACTIVE_POWER_CB(em_cb, cb) ((em_cb).active_power = cb) +#define EM_ADV_DATA_CB(_active_power_cb, _cost_cb) \ + { .active_power = _active_power_cb, \ + .get_cost = _cost_cb } +#define EM_DATA_CB(_active_power_cb) \ + EM_ADV_DATA_CB(_active_power_cb, NULL) struct em_perf_domain *em_cpu_get(int cpu); struct em_perf_domain *em_pd_get(struct device *dev); @@ -264,6 +285,7 @@ static inline int em_pd_nr_perf_states(struct em_perf_domain *pd) #else struct em_data_callback {}; +#define EM_ADV_DATA_CB(_active_power_cb, _cost_cb) { } #define EM_DATA_CB(_active_power_cb) { } #define EM_SET_ACTIVE_POWER_CB(em_cb, cb) do { } while (0) -- cgit v1.2.3 From fc3a9a9858478ab5f8441765a3f9552a0ceba10c Mon Sep 17 00:00:00 2001 From: Pierre Gondois Date: Mon, 21 Mar 2022 09:57:23 +0000 Subject: PM: EM: Add artificial EM flag The Energy Model (EM) can be used on platforms which are missing real power information. Those platforms would implement .get_cost() which populates needed values for the Energy Aware Scheduler (EAS). The EAS doesn't use 'power' fields from EM, but other frameworks might use them. Thus, to avoid miss-usage of this specific type of EM, introduce a new flags which can be checked by other frameworks. Signed-off-by: Pierre Gondois Signed-off-by: Lukasz Luba Reviewed-by: Ionela Voinescu Signed-off-by: Rafael J. Wysocki --- include/linux/energy_model.h | 5 +++++ kernel/power/energy_model.c | 2 ++ 2 files changed, 7 insertions(+) diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h index 0a3a5663177b..92e82a322859 100644 --- a/include/linux/energy_model.h +++ b/include/linux/energy_model.h @@ -67,11 +67,16 @@ struct em_perf_domain { * * EM_PERF_DOMAIN_SKIP_INEFFICIENCIES: Skip inefficient states when estimating * energy consumption. + * + * EM_PERF_DOMAIN_ARTIFICIAL: The power values are artificial and might be + * created by platform missing real power information */ #define EM_PERF_DOMAIN_MILLIWATTS BIT(0) #define EM_PERF_DOMAIN_SKIP_INEFFICIENCIES BIT(1) +#define EM_PERF_DOMAIN_ARTIFICIAL BIT(2) #define em_span_cpus(em) (to_cpumask((em)->cpus)) +#define em_is_artificial(em) ((em)->flags & EM_PERF_DOMAIN_ARTIFICIAL) #ifdef CONFIG_ENERGY_MODEL #define EM_MAX_POWER 0xFFFF diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c index 0153b0ca7b23..6ecee99af842 100644 --- a/kernel/power/energy_model.c +++ b/kernel/power/energy_model.c @@ -384,6 +384,8 @@ int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states, if (milliwatts) dev->em_pd->flags |= EM_PERF_DOMAIN_MILLIWATTS; + else if (cb->get_cost) + dev->em_pd->flags |= EM_PERF_DOMAIN_ARTIFICIAL; em_cpufreq_update_efficiencies(dev); -- cgit v1.2.3 From 91362463114eb63ead5f02c11d58c46064c339e7 Mon Sep 17 00:00:00 2001 From: Lukasz Luba Date: Mon, 21 Mar 2022 09:57:24 +0000 Subject: PM: EM: Use the new .get_cost() callback while registering EM The Energy Model (EM) allows to provide the 'cost' values when the device driver provides the .get_cost() optional callback. This removes restriction which is in the EM calculation function of the 'cost' for each performance state. Now, the driver is in charge of providing the right values which are then used by Energy Aware Scheduler. Signed-off-by: Lukasz Luba Reviewed-by: Ionela Voinescu Signed-off-by: Rafael J. Wysocki --- kernel/power/energy_model.c | 39 ++++++++++++++++++++++++++++----------- 1 file changed, 28 insertions(+), 11 deletions(-) diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c index 6ecee99af842..95a3b33001f6 100644 --- a/kernel/power/energy_model.c +++ b/kernel/power/energy_model.c @@ -121,7 +121,8 @@ static void em_debug_remove_pd(struct device *dev) {} #endif static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd, - int nr_states, struct em_data_callback *cb) + int nr_states, struct em_data_callback *cb, + unsigned long flags) { unsigned long power, freq, prev_freq = 0, prev_cost = ULONG_MAX; struct em_perf_state *table; @@ -173,10 +174,22 @@ static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd, /* Compute the cost of each performance state. */ fmax = (u64) table[nr_states - 1].frequency; for (i = nr_states - 1; i >= 0; i--) { - unsigned long power_res = em_scale_power(table[i].power); + unsigned long power_res, cost; + + if (flags & EM_PERF_DOMAIN_ARTIFICIAL) { + ret = cb->get_cost(dev, table[i].frequency, &cost); + if (ret || !cost || cost > EM_MAX_POWER) { + dev_err(dev, "EM: invalid cost %lu %d\n", + cost, ret); + goto free_ps_table; + } + } else { + power_res = em_scale_power(table[i].power); + cost = div64_u64(fmax * power_res, table[i].frequency); + } + + table[i].cost = cost; - table[i].cost = div64_u64(fmax * power_res, - table[i].frequency); if (table[i].cost >= prev_cost) { table[i].flags = EM_PERF_STATE_INEFFICIENT; dev_dbg(dev, "EM: OPP:%lu is inefficient\n", @@ -197,7 +210,8 @@ free_ps_table: } static int em_create_pd(struct device *dev, int nr_states, - struct em_data_callback *cb, cpumask_t *cpus) + struct em_data_callback *cb, cpumask_t *cpus, + unsigned long flags) { struct em_perf_domain *pd; struct device *cpu_dev; @@ -215,7 +229,7 @@ static int em_create_pd(struct device *dev, int nr_states, return -ENOMEM; } - ret = em_create_perf_table(dev, pd, nr_states, cb); + ret = em_create_perf_table(dev, pd, nr_states, cb, flags); if (ret) { kfree(pd); return ret; @@ -332,6 +346,7 @@ int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states, bool milliwatts) { unsigned long cap, prev_cap = 0; + unsigned long flags = 0; int cpu, ret; if (!dev || !nr_states || !cb) @@ -378,14 +393,16 @@ int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states, } } - ret = em_create_pd(dev, nr_states, cb, cpus); + if (milliwatts) + flags |= EM_PERF_DOMAIN_MILLIWATTS; + else if (cb->get_cost) + flags |= EM_PERF_DOMAIN_ARTIFICIAL; + + ret = em_create_pd(dev, nr_states, cb, cpus, flags); if (ret) goto unlock; - if (milliwatts) - dev->em_pd->flags |= EM_PERF_DOMAIN_MILLIWATTS; - else if (cb->get_cost) - dev->em_pd->flags |= EM_PERF_DOMAIN_ARTIFICIAL; + dev->em_pd->flags |= flags; em_cpufreq_update_efficiencies(dev); -- cgit v1.2.3 From 75a3a99a5a9886af13be44e640cb415ebda80db2 Mon Sep 17 00:00:00 2001 From: Lukasz Luba Date: Mon, 21 Mar 2022 09:57:25 +0000 Subject: PM: EM: Change the order of arguments in the .active_power() callback The .active_power() callback passes the device pointer when it's called. Aligned with a convetion present in other subsystems and pass the 'dev' as a first argument. It looks more cleaner. Adjust all affected drivers which implement that API callback. Suggested-by: Ionela Voinescu Signed-off-by: Lukasz Luba Reviewed-by: Ionela Voinescu Signed-off-by: Rafael J. Wysocki --- Documentation/power/energy-model.rst | 4 ++-- drivers/cpufreq/mediatek-cpufreq-hw.c | 4 ++-- drivers/cpufreq/scmi-cpufreq.c | 4 ++-- drivers/opp/of.c | 6 +++--- include/linux/energy_model.h | 6 +++--- kernel/power/energy_model.c | 2 +- 6 files changed, 13 insertions(+), 13 deletions(-) diff --git a/Documentation/power/energy-model.rst b/Documentation/power/energy-model.rst index 49549aab41b4..fd29ed2506c0 100644 --- a/Documentation/power/energy-model.rst +++ b/Documentation/power/energy-model.rst @@ -181,8 +181,8 @@ EM framework:: -> drivers/cpufreq/foo_cpufreq.c - 01 static int est_power(unsigned long *mW, unsigned long *KHz, - 02 struct device *dev) + 01 static int est_power(struct device *dev, unsigned long *mW, + 02 unsigned long *KHz) 03 { 04 long freq, power; 05 diff --git a/drivers/cpufreq/mediatek-cpufreq-hw.c b/drivers/cpufreq/mediatek-cpufreq-hw.c index 0a94c56ddad2..813cccbfe934 100644 --- a/drivers/cpufreq/mediatek-cpufreq-hw.c +++ b/drivers/cpufreq/mediatek-cpufreq-hw.c @@ -51,8 +51,8 @@ static const u16 cpufreq_mtk_offsets[REG_ARRAY_SIZE] = { }; static int __maybe_unused -mtk_cpufreq_get_cpu_power(unsigned long *mW, - unsigned long *KHz, struct device *cpu_dev) +mtk_cpufreq_get_cpu_power(struct device *cpu_dev, unsigned long *mW, + unsigned long *KHz) { struct mtk_cpufreq_data *data; struct cpufreq_policy *policy; diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c index 919fa6e3f462..6d2a4cf46db7 100644 --- a/drivers/cpufreq/scmi-cpufreq.c +++ b/drivers/cpufreq/scmi-cpufreq.c @@ -96,8 +96,8 @@ scmi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask) } static int __maybe_unused -scmi_get_cpu_power(unsigned long *power, unsigned long *KHz, - struct device *cpu_dev) +scmi_get_cpu_power(struct device *cpu_dev, unsigned long *power, + unsigned long *KHz) { unsigned long Hz; int ret, domain; diff --git a/drivers/opp/of.c b/drivers/opp/of.c index 440ab5a03df9..485ea980bde7 100644 --- a/drivers/opp/of.c +++ b/drivers/opp/of.c @@ -1448,7 +1448,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_of_node); * Returns 0 on success or a proper -EINVAL value in case of error. */ static int __maybe_unused -_get_dt_power(unsigned long *mW, unsigned long *kHz, struct device *dev) +_get_dt_power(struct device *dev, unsigned long *mW, unsigned long *kHz) { struct dev_pm_opp *opp; unsigned long opp_freq, opp_power; @@ -1482,8 +1482,8 @@ _get_dt_power(unsigned long *mW, unsigned long *kHz, struct device *dev) * Returns -EINVAL if the power calculation failed because of missing * parameters, 0 otherwise. */ -static int __maybe_unused _get_power(unsigned long *mW, unsigned long *kHz, - struct device *dev) +static int __maybe_unused _get_power(struct device *dev, unsigned long *mW, + unsigned long *kHz) { struct dev_pm_opp *opp; struct device_node *np; diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h index 92e82a322859..8419bffb4398 100644 --- a/include/linux/energy_model.h +++ b/include/linux/energy_model.h @@ -101,11 +101,11 @@ struct em_data_callback { /** * active_power() - Provide power at the next performance state of * a device + * @dev : Device for which we do this operation (can be a CPU) * @power : Active power at the performance state * (modified) * @freq : Frequency at the performance state in kHz * (modified) - * @dev : Device for which we do this operation (can be a CPU) * * active_power() must find the lowest performance state of 'dev' above * 'freq' and update 'power' and 'freq' to the matching active power @@ -117,8 +117,8 @@ struct em_data_callback { * * Return 0 on success. */ - int (*active_power)(unsigned long *power, unsigned long *freq, - struct device *dev); + int (*active_power)(struct device *dev, unsigned long *power, + unsigned long *freq); /** * get_cost() - Provide the cost at the given performance state of diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c index 95a3b33001f6..babefc72085d 100644 --- a/kernel/power/energy_model.c +++ b/kernel/power/energy_model.c @@ -140,7 +140,7 @@ static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd, * lowest performance state of 'dev' above 'freq' and updates * 'power' and 'freq' accordingly. */ - ret = cb->active_power(&power, &freq, dev); + ret = cb->active_power(dev, &power, &freq); if (ret) { dev_err(dev, "EM: invalid perf. state: %d\n", ret); -- cgit v1.2.3 From 16857482b830544f5849daa1048f82d00b68957e Mon Sep 17 00:00:00 2001 From: Lukasz Luba Date: Mon, 21 Mar 2022 09:57:26 +0000 Subject: PM: EM: Remove old debugfs files and print all 'flags' The Energy Model gets more bits used in 'flags'. Avoid adding another debugfs file just to print what is the status of a new flag. Simply remove old debugfs files and add one generic which prints all flags as a hex value. Signed-off-by: Lukasz Luba Reviewed-by: Ionela Voinescu Signed-off-by: Rafael J. Wysocki --- kernel/power/energy_model.c | 24 +++++------------------- 1 file changed, 5 insertions(+), 19 deletions(-) diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c index babefc72085d..092513575e4e 100644 --- a/kernel/power/energy_model.c +++ b/kernel/power/energy_model.c @@ -54,28 +54,15 @@ static int em_debug_cpus_show(struct seq_file *s, void *unused) } DEFINE_SHOW_ATTRIBUTE(em_debug_cpus); -static int em_debug_units_show(struct seq_file *s, void *unused) +static int em_debug_flags_show(struct seq_file *s, void *unused) { struct em_perf_domain *pd = s->private; - char *units = (pd->flags & EM_PERF_DOMAIN_MILLIWATTS) ? - "milliWatts" : "bogoWatts"; - seq_printf(s, "%s\n", units); + seq_printf(s, "%#lx\n", pd->flags); return 0; } -DEFINE_SHOW_ATTRIBUTE(em_debug_units); - -static int em_debug_skip_inefficiencies_show(struct seq_file *s, void *unused) -{ - struct em_perf_domain *pd = s->private; - int enabled = (pd->flags & EM_PERF_DOMAIN_SKIP_INEFFICIENCIES) ? 1 : 0; - - seq_printf(s, "%d\n", enabled); - - return 0; -} -DEFINE_SHOW_ATTRIBUTE(em_debug_skip_inefficiencies); +DEFINE_SHOW_ATTRIBUTE(em_debug_flags); static void em_debug_create_pd(struct device *dev) { @@ -89,9 +76,8 @@ static void em_debug_create_pd(struct device *dev) debugfs_create_file("cpus", 0444, d, dev->em_pd->cpus, &em_debug_cpus_fops); - debugfs_create_file("units", 0444, d, dev->em_pd, &em_debug_units_fops); - debugfs_create_file("skip-inefficiencies", 0444, d, dev->em_pd, - &em_debug_skip_inefficiencies_fops); + debugfs_create_file("flags", 0444, d, dev->em_pd, + &em_debug_flags_fops); /* Create a sub-directory for each performance state */ for (i = 0; i < dev->em_pd->nr_perf_states; i++) -- cgit v1.2.3 From 015f569c4649fe9595ed465dc8e4301d34937f8f Mon Sep 17 00:00:00 2001 From: Lukasz Luba Date: Mon, 21 Mar 2022 09:57:27 +0000 Subject: Documentation: EM: Add artificial EM registration description Add description about new artificial EM registration and use cases. Update also the documentation with the new .get_cost() callback description and usage. Signed-off-by: Lukasz Luba Reviewed-by: Ionela Voinescu Signed-off-by: Rafael J. Wysocki --- Documentation/power/energy-model.rst | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/Documentation/power/energy-model.rst b/Documentation/power/energy-model.rst index fd29ed2506c0..feb257b7f350 100644 --- a/Documentation/power/energy-model.rst +++ b/Documentation/power/energy-model.rst @@ -123,6 +123,26 @@ allows a platform to register EM power values which are reflecting total power (static + dynamic). These power values might be coming directly from experiments and measurements. +Registration of 'artificial' EM +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +There is an option to provide a custom callback for drivers missing detailed +knowledge about power value for each performance state. The callback +.get_cost() is optional and provides the 'cost' values used by the EAS. +This is useful for platforms that only provide information on relative +efficiency between CPU types, where one could use the information to +create an abstract power model. But even an abstract power model can +sometimes be hard to fit in, given the input power value size restrictions. +The .get_cost() allows to provide the 'cost' values which reflect the +efficiency of the CPUs. This would allow to provide EAS information which +has different relation than what would be forced by the EM internal +formulas calculating 'cost' values. To register an EM for such platform, the +driver must set the flag 'milliwatts' to 0, provide .get_power() callback +and provide .get_cost() callback. The EM framework would handle such platform +properly during registration. A flag EM_PERF_DOMAIN_ARTIFICIAL is set for such +platform. Special care should be taken by other frameworks which are using EM +to test and treat this flag properly. + Registration of 'simple' EM ~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- cgit v1.2.3 From 9926bbec3ae6c10d4e6fc297afde6a7ef7ad640b Mon Sep 17 00:00:00 2001 From: Lukasz Luba Date: Mon, 21 Mar 2022 09:57:28 +0000 Subject: thermal: cooling: Check Energy Model type in cpufreq_cooling and devfreq_cooling The Energy Model can now be artificial, which means the power values are mathematically generated to leverage EAS while not expected to be on an uniform scale with other devices providing power information. If this EM type is in use, the thermal governor IPA should not be allowed to operate, since the relation between cooling devices is not properly defined. Thus, it might be possible that big GPU has lower power values than a Little CPU. To mitigate a misbehaviour of the thermal control algorithm, simply do not register the cooling device as IPA's power actor. Signed-off-by: Lukasz Luba Acked-by: Viresh Kumar Reviewed-by: Ionela Voinescu Signed-off-by: Rafael J. Wysocki --- drivers/thermal/cpufreq_cooling.c | 2 +- drivers/thermal/devfreq_cooling.c | 8 +++++--- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c index 0bfb8eebd126..b8151d95a806 100644 --- a/drivers/thermal/cpufreq_cooling.c +++ b/drivers/thermal/cpufreq_cooling.c @@ -328,7 +328,7 @@ static inline bool em_is_sane(struct cpufreq_cooling_device *cpufreq_cdev, struct cpufreq_policy *policy; unsigned int nr_levels; - if (!em) + if (!em || em_is_artificial(em)) return false; policy = cpufreq_cdev->policy; diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c index 4310cb342a9f..b04dcbbf721a 100644 --- a/drivers/thermal/devfreq_cooling.c +++ b/drivers/thermal/devfreq_cooling.c @@ -358,6 +358,7 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df, struct thermal_cooling_device *cdev; struct device *dev = df->dev.parent; struct devfreq_cooling_device *dfc; + struct em_perf_domain *em; char *name; int err, num_opps; @@ -367,8 +368,9 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df, dfc->devfreq = df; - dfc->em_pd = em_pd_get(dev); - if (dfc->em_pd) { + em = em_pd_get(dev); + if (em && !em_is_artificial(em)) { + dfc->em_pd = em; devfreq_cooling_ops.get_requested_power = devfreq_cooling_get_requested_power; devfreq_cooling_ops.state2power = devfreq_cooling_state2power; @@ -379,7 +381,7 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df, num_opps = em_pd_nr_perf_states(dfc->em_pd); } else { /* Backward compatibility for drivers which do not use IPA */ - dev_dbg(dev, "missing EM for cooling device\n"); + dev_dbg(dev, "missing proper EM for cooling device\n"); num_opps = dev_pm_opp_get_opp_count(dev); -- cgit v1.2.3 From 985a67709a66c456414182ed179544786e00321e Mon Sep 17 00:00:00 2001 From: Lukasz Luba Date: Mon, 21 Mar 2022 09:57:29 +0000 Subject: powercap: DTPM: Check for Energy Model type The Energy Model power values might be artificial. In such case it's safe to bail out during the registration, since the PowerCap framework supports only micro-Watts. Signed-off-by: Lukasz Luba Reviewed-by: Ionela Voinescu Signed-off-by: Rafael J. Wysocki --- drivers/powercap/dtpm_cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/powercap/dtpm_cpu.c b/drivers/powercap/dtpm_cpu.c index bca2f912d349..f5eced0842b3 100644 --- a/drivers/powercap/dtpm_cpu.c +++ b/drivers/powercap/dtpm_cpu.c @@ -211,7 +211,7 @@ static int __dtpm_cpu_setup(int cpu, struct dtpm *parent) return 0; pd = em_cpu_get(cpu); - if (!pd) + if (!pd || em_is_artificial(pd)) return -EINVAL; dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL); -- cgit v1.2.3