| Message ID | 20230207171011.1596127-3-niklas.soderlund+renesas@ragnatech.se (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Daniel Lezcano |
| Headers | show |
| Series | drivers/thermal/rcar_gen3_thermal: Fix device initialization | expand |
On Tue, Feb 07, 2023 at 06:10:11PM +0100, Niklas Söderlund wrote: > The thermal zone is registered before the device is register and the > thermal coefficients are calculated, providing a window for very > incorrect readings. While I could never actually be in this race window, the patch makes a lot of sense to me. > The reason why the zone was register before the device was fully > initialized was that the presence of the set_trips() callback is used to > determine if the driver supports interrupt or not, as it is not defined > if the device is incapable of interrupts. > > Fix this by using the operations structure in the private data instead > of the zone to determine if interrupts are available or not, and > initialize the device before registering the zone. > > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com> One minor question: > - if (status) > + if (status && priv->tscs[i]->zone) > thermal_zone_device_update(priv->tscs[i]->zone, > THERMAL_EVENT_UNSPECIFIED); Isn't this a seperate change?
Hi Wolfram, Thanks for your review. On 2023-02-08 08:58:33 +0100, Wolfram Sang wrote: > On Tue, Feb 07, 2023 at 06:10:11PM +0100, Niklas Söderlund wrote: > > The thermal zone is registered before the device is register and the > > thermal coefficients are calculated, providing a window for very > > incorrect readings. > > While I could never actually be in this race window, the patch makes a > lot of sense to me. > > > The reason why the zone was register before the device was fully > > initialized was that the presence of the set_trips() callback is used to > > determine if the driver supports interrupt or not, as it is not defined > > if the device is incapable of interrupts. > > > > Fix this by using the operations structure in the private data instead > > of the zone to determine if interrupts are available or not, and > > initialize the device before registering the zone. > > > > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> > > Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com> > > One minor question: > > > - if (status) > > + if (status && priv->tscs[i]->zone) > > thermal_zone_device_update(priv->tscs[i]->zone, > > THERMAL_EVENT_UNSPECIFIED); > > Isn't this a seperate change? Not really. This patch changes the driver to enable interrupts just before the zone is created. So this just guards from the very small window where an interrupt could be fired and the zone is created, which if it would happen would cause a null pointer dereference. While not updating a not yet created zone is fine. But this should never happen (tm) as the trip points have not been set when this window exists, but better safe then sorry.
On 07/02/2023 18:10, Niklas Söderlund wrote: > The thermal zone is registered before the device is register and the > thermal coefficients are calculated, providing a window for very > incorrect readings. > > The reason why the zone was register before the device was fully > initialized was that the presence of the set_trips() callback is used to > determine if the driver supports interrupt or not, as it is not defined > if the device is incapable of interrupts. > > Fix this by using the operations structure in the private data instead > of the zone to determine if interrupts are available or not, and > initialize the device before registering the zone. > > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> > --- > drivers/thermal/rcar_gen3_thermal.c | 25 ++++++++++++++----------- > 1 file changed, 14 insertions(+), 11 deletions(-) > > diff --git a/drivers/thermal/rcar_gen3_thermal.c b/drivers/thermal/rcar_gen3_thermal.c > index bfa2ff20b945..1dedeece1a00 100644 > --- a/drivers/thermal/rcar_gen3_thermal.c > +++ b/drivers/thermal/rcar_gen3_thermal.c > @@ -89,7 +89,8 @@ struct rcar_gen3_thermal_priv { > struct rcar_gen3_thermal_tsc *tscs[TSC_MAX_NUM]; > struct thermal_zone_device_ops ops; > unsigned int num_tscs; > - void (*thermal_init)(struct rcar_gen3_thermal_tsc *tsc); > + void (*thermal_init)(struct rcar_gen3_thermal_priv *priv, > + struct rcar_gen3_thermal_tsc *tsc); > int ptat[3]; > }; > > @@ -240,7 +241,7 @@ static irqreturn_t rcar_gen3_thermal_irq(int irq, void *data) > for (i = 0; i < priv->num_tscs; i++) { > status = rcar_gen3_thermal_read(priv->tscs[i], REG_GEN3_IRQSTR); > rcar_gen3_thermal_write(priv->tscs[i], REG_GEN3_IRQSTR, 0); > - if (status) > + if (status && priv->tscs[i]->zone) > thermal_zone_device_update(priv->tscs[i]->zone, > THERMAL_EVENT_UNSPECIFIED); > } > @@ -311,7 +312,8 @@ static bool rcar_gen3_thermal_read_fuses(struct rcar_gen3_thermal_priv *priv) > return true; > } > > -static void rcar_gen3_thermal_init_r8a7795es1(struct rcar_gen3_thermal_tsc *tsc) > +static void rcar_gen3_thermal_init_r8a7795es1(struct rcar_gen3_thermal_priv *priv, > + struct rcar_gen3_thermal_tsc *tsc) > { > rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, CTSR_THBGR); > rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, 0x0); > @@ -322,7 +324,7 @@ static void rcar_gen3_thermal_init_r8a7795es1(struct rcar_gen3_thermal_tsc *tsc) > > rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0x3F); > rcar_gen3_thermal_write(tsc, REG_GEN3_IRQMSK, 0); > - if (tsc->zone->ops->set_trips) > + if (priv->ops.set_trips) > rcar_gen3_thermal_write(tsc, REG_GEN3_IRQEN, > IRQ_TEMPD1 | IRQ_TEMP2); > > @@ -338,7 +340,8 @@ static void rcar_gen3_thermal_init_r8a7795es1(struct rcar_gen3_thermal_tsc *tsc) > usleep_range(1000, 2000); > } > > -static void rcar_gen3_thermal_init(struct rcar_gen3_thermal_tsc *tsc) > +static void rcar_gen3_thermal_init(struct rcar_gen3_thermal_priv *priv, > + struct rcar_gen3_thermal_tsc *tsc) > { > u32 reg_val; > > @@ -350,7 +353,7 @@ static void rcar_gen3_thermal_init(struct rcar_gen3_thermal_tsc *tsc) > > rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0); > rcar_gen3_thermal_write(tsc, REG_GEN3_IRQMSK, 0); > - if (tsc->zone->ops->set_trips) > + if (priv->ops.set_trips) > rcar_gen3_thermal_write(tsc, REG_GEN3_IRQEN, > IRQ_TEMPD1 | IRQ_TEMP2); > > @@ -510,6 +513,9 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev) > for (i = 0; i < priv->num_tscs; i++) { > struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i]; > > + priv->thermal_init(priv, tsc); > + rcar_gen3_thermal_calc_coefs(priv, tsc, *ths_tj_1); > + > zone = devm_thermal_of_zone_register(dev, i, tsc, &priv->ops); > if (IS_ERR(zone)) { > dev_err(dev, "Sensor %u: Can't register thermal zone\n", i); > @@ -518,9 +524,6 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev) > } > tsc->zone = zone; > > - priv->thermal_init(tsc); > - rcar_gen3_thermal_calc_coefs(priv, tsc, *ths_tj_1); > - > tsc->zone->tzp->no_hwmon = false; > ret = thermal_add_hwmon_sysfs(tsc->zone); > if (ret) > @@ -559,8 +562,8 @@ static int __maybe_unused rcar_gen3_thermal_resume(struct device *dev) > struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i]; > struct thermal_zone_device *zone = tsc->zone; > > - priv->thermal_init(tsc); > - if (zone->ops->set_trips) > + priv->thermal_init(priv, tsc); > + if (priv->ops.set_trips) > rcar_gen3_thermal_set_trips(zone, zone->prev_low_trip, > zone->prev_high_trip); This is not needed, at resume time, the thermal framework has a pm_notifier and calls thermal_zone_device_update() which in turn calls thermal_zone_set_trips(). If the ops is not set, it will continue. Actually, no call to set_trips should happen in the driver, just pass the ops the thermal framework and it will do the actions. The same happens when you call thermal_zone_device_register(), it calls thermal_zone_device_update(), then thermal_zone_set_trips().
> While not updating a not yet created zone is fine. But this should never > happen (tm) as the trip points have not been set when this window > exists, but better safe then sorry. Full Ack! Thanks for the heads up.
Hi Daniel, Thanks for your feedback. On 2023-02-08 12:06:37 +0100, Daniel Lezcano wrote: > On 07/02/2023 18:10, Niklas Söderlund wrote: > > The thermal zone is registered before the device is register and the > > thermal coefficients are calculated, providing a window for very > > incorrect readings. > > > > The reason why the zone was register before the device was fully > > initialized was that the presence of the set_trips() callback is used to > > determine if the driver supports interrupt or not, as it is not defined > > if the device is incapable of interrupts. > > > > Fix this by using the operations structure in the private data instead > > of the zone to determine if interrupts are available or not, and > > initialize the device before registering the zone. > > > > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> > > --- > > drivers/thermal/rcar_gen3_thermal.c | 25 ++++++++++++++----------- > > 1 file changed, 14 insertions(+), 11 deletions(-) > > > > diff --git a/drivers/thermal/rcar_gen3_thermal.c b/drivers/thermal/rcar_gen3_thermal.c > > index bfa2ff20b945..1dedeece1a00 100644 > > --- a/drivers/thermal/rcar_gen3_thermal.c > > +++ b/drivers/thermal/rcar_gen3_thermal.c > > @@ -89,7 +89,8 @@ struct rcar_gen3_thermal_priv { > > struct rcar_gen3_thermal_tsc *tscs[TSC_MAX_NUM]; > > struct thermal_zone_device_ops ops; > > unsigned int num_tscs; > > - void (*thermal_init)(struct rcar_gen3_thermal_tsc *tsc); > > + void (*thermal_init)(struct rcar_gen3_thermal_priv *priv, > > + struct rcar_gen3_thermal_tsc *tsc); > > int ptat[3]; > > }; > > @@ -240,7 +241,7 @@ static irqreturn_t rcar_gen3_thermal_irq(int irq, void *data) > > for (i = 0; i < priv->num_tscs; i++) { > > status = rcar_gen3_thermal_read(priv->tscs[i], REG_GEN3_IRQSTR); > > rcar_gen3_thermal_write(priv->tscs[i], REG_GEN3_IRQSTR, 0); > > - if (status) > > + if (status && priv->tscs[i]->zone) > > thermal_zone_device_update(priv->tscs[i]->zone, > > THERMAL_EVENT_UNSPECIFIED); > > } > > @@ -311,7 +312,8 @@ static bool rcar_gen3_thermal_read_fuses(struct rcar_gen3_thermal_priv *priv) > > return true; > > } > > -static void rcar_gen3_thermal_init_r8a7795es1(struct rcar_gen3_thermal_tsc *tsc) > > +static void rcar_gen3_thermal_init_r8a7795es1(struct rcar_gen3_thermal_priv *priv, > > + struct rcar_gen3_thermal_tsc *tsc) > > { > > rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, CTSR_THBGR); > > rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, 0x0); > > @@ -322,7 +324,7 @@ static void rcar_gen3_thermal_init_r8a7795es1(struct rcar_gen3_thermal_tsc *tsc) > > rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0x3F); > > rcar_gen3_thermal_write(tsc, REG_GEN3_IRQMSK, 0); > > - if (tsc->zone->ops->set_trips) > > + if (priv->ops.set_trips) > > rcar_gen3_thermal_write(tsc, REG_GEN3_IRQEN, > > IRQ_TEMPD1 | IRQ_TEMP2); > > @@ -338,7 +340,8 @@ static void rcar_gen3_thermal_init_r8a7795es1(struct rcar_gen3_thermal_tsc *tsc) > > usleep_range(1000, 2000); > > } > > -static void rcar_gen3_thermal_init(struct rcar_gen3_thermal_tsc *tsc) > > +static void rcar_gen3_thermal_init(struct rcar_gen3_thermal_priv *priv, > > + struct rcar_gen3_thermal_tsc *tsc) > > { > > u32 reg_val; > > @@ -350,7 +353,7 @@ static void rcar_gen3_thermal_init(struct rcar_gen3_thermal_tsc *tsc) > > rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0); > > rcar_gen3_thermal_write(tsc, REG_GEN3_IRQMSK, 0); > > - if (tsc->zone->ops->set_trips) > > + if (priv->ops.set_trips) > > rcar_gen3_thermal_write(tsc, REG_GEN3_IRQEN, > > IRQ_TEMPD1 | IRQ_TEMP2); > > @@ -510,6 +513,9 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev) > > for (i = 0; i < priv->num_tscs; i++) { > > struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i]; > > + priv->thermal_init(priv, tsc); > > + rcar_gen3_thermal_calc_coefs(priv, tsc, *ths_tj_1); > > + > > zone = devm_thermal_of_zone_register(dev, i, tsc, &priv->ops); > > if (IS_ERR(zone)) { > > dev_err(dev, "Sensor %u: Can't register thermal zone\n", i); > > @@ -518,9 +524,6 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev) > > } > > tsc->zone = zone; > > - priv->thermal_init(tsc); > > - rcar_gen3_thermal_calc_coefs(priv, tsc, *ths_tj_1); > > - > > tsc->zone->tzp->no_hwmon = false; > > ret = thermal_add_hwmon_sysfs(tsc->zone); > > if (ret) > > @@ -559,8 +562,8 @@ static int __maybe_unused rcar_gen3_thermal_resume(struct device *dev) > > struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i]; > > struct thermal_zone_device *zone = tsc->zone; > > - priv->thermal_init(tsc); > > - if (zone->ops->set_trips) > > + priv->thermal_init(priv, tsc); > > + if (priv->ops.set_trips) > > rcar_gen3_thermal_set_trips(zone, zone->prev_low_trip, > > zone->prev_high_trip); > > This is not needed, at resume time, the thermal framework has a pm_notifier > and calls thermal_zone_device_update() which in turn calls > thermal_zone_set_trips(). If the ops is not set, it will continue. > > Actually, no call to set_trips should happen in the driver, just pass the > ops the thermal framework and it will do the actions. > > The same happens when you call thermal_zone_device_register(), it calls > thermal_zone_device_update(), then thermal_zone_set_trips(). I will send a v2 of this series addressing this before fixing the issue addressed in this patch. > > > -- > <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs > > Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | > <http://twitter.com/#!/linaroorg> Twitter | > <http://www.linaro.org/linaro-blog/> Blog >
diff --git a/drivers/thermal/rcar_gen3_thermal.c b/drivers/thermal/rcar_gen3_thermal.c index bfa2ff20b945..1dedeece1a00 100644 --- a/drivers/thermal/rcar_gen3_thermal.c +++ b/drivers/thermal/rcar_gen3_thermal.c @@ -89,7 +89,8 @@ struct rcar_gen3_thermal_priv { struct rcar_gen3_thermal_tsc *tscs[TSC_MAX_NUM]; struct thermal_zone_device_ops ops; unsigned int num_tscs; - void (*thermal_init)(struct rcar_gen3_thermal_tsc *tsc); + void (*thermal_init)(struct rcar_gen3_thermal_priv *priv, + struct rcar_gen3_thermal_tsc *tsc); int ptat[3]; }; @@ -240,7 +241,7 @@ static irqreturn_t rcar_gen3_thermal_irq(int irq, void *data) for (i = 0; i < priv->num_tscs; i++) { status = rcar_gen3_thermal_read(priv->tscs[i], REG_GEN3_IRQSTR); rcar_gen3_thermal_write(priv->tscs[i], REG_GEN3_IRQSTR, 0); - if (status) + if (status && priv->tscs[i]->zone) thermal_zone_device_update(priv->tscs[i]->zone, THERMAL_EVENT_UNSPECIFIED); } @@ -311,7 +312,8 @@ static bool rcar_gen3_thermal_read_fuses(struct rcar_gen3_thermal_priv *priv) return true; } -static void rcar_gen3_thermal_init_r8a7795es1(struct rcar_gen3_thermal_tsc *tsc) +static void rcar_gen3_thermal_init_r8a7795es1(struct rcar_gen3_thermal_priv *priv, + struct rcar_gen3_thermal_tsc *tsc) { rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, CTSR_THBGR); rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, 0x0); @@ -322,7 +324,7 @@ static void rcar_gen3_thermal_init_r8a7795es1(struct rcar_gen3_thermal_tsc *tsc) rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0x3F); rcar_gen3_thermal_write(tsc, REG_GEN3_IRQMSK, 0); - if (tsc->zone->ops->set_trips) + if (priv->ops.set_trips) rcar_gen3_thermal_write(tsc, REG_GEN3_IRQEN, IRQ_TEMPD1 | IRQ_TEMP2); @@ -338,7 +340,8 @@ static void rcar_gen3_thermal_init_r8a7795es1(struct rcar_gen3_thermal_tsc *tsc) usleep_range(1000, 2000); } -static void rcar_gen3_thermal_init(struct rcar_gen3_thermal_tsc *tsc) +static void rcar_gen3_thermal_init(struct rcar_gen3_thermal_priv *priv, + struct rcar_gen3_thermal_tsc *tsc) { u32 reg_val; @@ -350,7 +353,7 @@ static void rcar_gen3_thermal_init(struct rcar_gen3_thermal_tsc *tsc) rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0); rcar_gen3_thermal_write(tsc, REG_GEN3_IRQMSK, 0); - if (tsc->zone->ops->set_trips) + if (priv->ops.set_trips) rcar_gen3_thermal_write(tsc, REG_GEN3_IRQEN, IRQ_TEMPD1 | IRQ_TEMP2); @@ -510,6 +513,9 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev) for (i = 0; i < priv->num_tscs; i++) { struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i]; + priv->thermal_init(priv, tsc); + rcar_gen3_thermal_calc_coefs(priv, tsc, *ths_tj_1); + zone = devm_thermal_of_zone_register(dev, i, tsc, &priv->ops); if (IS_ERR(zone)) { dev_err(dev, "Sensor %u: Can't register thermal zone\n", i); @@ -518,9 +524,6 @@ static int rcar_gen3_thermal_probe(struct platform_device *pdev) } tsc->zone = zone; - priv->thermal_init(tsc); - rcar_gen3_thermal_calc_coefs(priv, tsc, *ths_tj_1); - tsc->zone->tzp->no_hwmon = false; ret = thermal_add_hwmon_sysfs(tsc->zone); if (ret) @@ -559,8 +562,8 @@ static int __maybe_unused rcar_gen3_thermal_resume(struct device *dev) struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i]; struct thermal_zone_device *zone = tsc->zone; - priv->thermal_init(tsc); - if (zone->ops->set_trips) + priv->thermal_init(priv, tsc); + if (priv->ops.set_trips) rcar_gen3_thermal_set_trips(zone, zone->prev_low_trip, zone->prev_high_trip); }
The thermal zone is registered before the device is register and the thermal coefficients are calculated, providing a window for very incorrect readings. The reason why the zone was register before the device was fully initialized was that the presence of the set_trips() callback is used to determine if the driver supports interrupt or not, as it is not defined if the device is incapable of interrupts. Fix this by using the operations structure in the private data instead of the zone to determine if interrupts are available or not, and initialize the device before registering the zone. Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> --- drivers/thermal/rcar_gen3_thermal.c | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-)