On Tue, Nov 08, 2022 at 03:50:50PM +0800, Zhang Rui wrote:
> Tjmax value retrieved from MSR_IA32_TEMPERATURE_TARGET can be changed at
> runtime when the Intel SST-PP (Intel Speed Select Technology -
> Performance Profile) level is changed.
>
> Improve the code to always use updated tjmax when it can be retrieved
> from MSR_IA32_TEMPERATURE_TARGET.
>
> When tjmax can not be retrieved from MSR_IA32_TEMPERATURE_TARGET, still
> follow the previous logic and always use a static tjmax value.
>
> Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> ---
> drivers/hwmon/coretemp.c | 40 ++++++++++++++++++++++++++++++----------
> 1 file changed, 30 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
> index ec35ada68455..5292f7844860 100644
> --- a/drivers/hwmon/coretemp.c
> +++ b/drivers/hwmon/coretemp.c
> @@ -55,6 +55,8 @@ MODULE_PARM_DESC(tjmax, "TjMax value in degrees Celsius");
>
> /*
> * Per-Core Temperature Data
> + * @tjmax: The static tjmax value when tjmax cannot be retrieved from
> + * IA32_TEMPERATURE_TARGET MSR.
> * @last_updated: The time when the current temperature value was updated
> * earlier (in jiffies).
> * @cpu_core_id: The CPU Core from which temperature values should be read
> @@ -93,6 +95,8 @@ struct platform_data {
> struct device_attribute name_attr;
> };
>
> +static int get_tjmax(struct temp_data *tdata, struct device *dev);
> +
Please rearrange the code to avoid the forward declaration.
> /* Keep track of how many zone pointers we allocated in init() */
> static int max_zones __read_mostly;
> /* Array of zone pointers. Serialized by cpu hotplug lock */
> @@ -131,8 +135,14 @@ static ssize_t show_tjmax(struct device *dev,
> {
> struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> struct platform_data *pdata = dev_get_drvdata(dev);
> + struct temp_data *tdata = pdata->core_data[attr->index];
> + int tjmax;
> +
> + mutex_lock(&tdata->update_lock);
> + tjmax = get_tjmax(tdata, dev);
> + mutex_unlock(&tdata->update_lock);
>
> - return sprintf(buf, "%d\n", pdata->core_data[attr->index]->tjmax);
> + return sprintf(buf, "%d\n", tjmax);
> }
>
> static ssize_t show_ttarget(struct device *dev,
> @@ -151,9 +161,11 @@ static ssize_t show_temp(struct device *dev,
> struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> struct platform_data *pdata = dev_get_drvdata(dev);
> struct temp_data *tdata = pdata->core_data[attr->index];
> + int tjmax;
>
> mutex_lock(&tdata->update_lock);
>
> + tjmax = get_tjmax(tdata, dev);
> /* Check whether the time interval has elapsed */
> if (time_after(jiffies, tdata->last_updated + HZ)) {
> rdmsr_on_cpu(tdata->cpu, tdata->status_reg, &eax, &edx);
> @@ -163,7 +175,7 @@ static ssize_t show_temp(struct device *dev,
> * Return it instead of reporting an error which doesn't
> * really help at all.
> */
> - tdata->temp = tdata->tjmax - ((eax >> 16) & 0x7f) * 1000;
> + tdata->temp = tjmax - ((eax >> 16) & 0x7f) * 1000;
> tdata->last_updated = jiffies;
> }
>
> @@ -334,20 +346,25 @@ static bool cpu_has_tjmax(struct cpuinfo_x86 *c)
> model != 0x36;
> }
>
> -static int get_tjmax(struct cpuinfo_x86 *c, u32 id, struct device *dev)
> +static int get_tjmax(struct temp_data *tdata, struct device *dev)
> {
> + struct cpuinfo_x86 *c = &cpu_data(tdata->cpu);
> int err;
> u32 eax, edx;
> u32 val;
>
> + /* use static tjmax once it is set */
> + if (tdata->tjmax)
> + return tdata->tjmax;
> +
> /*
> * A new feature of current Intel(R) processors, the
> * IA32_TEMPERATURE_TARGET contains the TjMax value
> */
> - err = rdmsr_safe_on_cpu(id, MSR_IA32_TEMPERATURE_TARGET, &eax, &edx);
> + err = rdmsr_safe_on_cpu(tdata->cpu, MSR_IA32_TEMPERATURE_TARGET, &eax, &edx);
> if (err) {
> if (cpu_has_tjmax(c))
> - dev_warn(dev, "Unable to read TjMax from CPU %u\n", id);
> + dev_warn(dev, "Unable to read TjMax from CPU %u\n", tdata->cpu);
> } else {
> val = (eax >> 16) & 0xff;
> /*
> @@ -363,14 +380,17 @@ static int get_tjmax(struct cpuinfo_x86 *c, u32 id, struct device *dev)
> if (force_tjmax) {
> dev_notice(dev, "TjMax forced to %d degrees C by user\n",
> force_tjmax);
> - return force_tjmax * 1000;
> + tdata->tjmax = force_tjmax * 1000;
> + goto end;
This added goto doesn't add any value and is just a manual replacement
for if/else. Please drop and return immediately, or use if/else.
if (force_tjmax) {
...
tdata->tjmax = force_tjmax * 1000;
} else {
/*
* An assumption is made for early CPUs and unreadable MSR.
* NOTE: the calculated value may not be correct.
*/
tdata->tjmax = adjust_tjmax(c, tdata->cpu, dev);
}
return tdata->tjmax;
Thanks,
Guenter
> }
>
> /*
> * An assumption is made for early CPUs and unreadable MSR.
> * NOTE: the calculated value may not be correct.
> */
> - return adjust_tjmax(c, id, dev);
> + tdata->tjmax = adjust_tjmax(c, tdata->cpu, dev);
> +end:
> + return tdata->tjmax;
> }
>
> static int create_core_attrs(struct temp_data *tdata, struct device *dev,
> @@ -450,7 +470,7 @@ static int create_core_data(struct platform_device *pdev, unsigned int cpu,
> struct platform_data *pdata = platform_get_drvdata(pdev);
> struct cpuinfo_x86 *c = &cpu_data(cpu);
> u32 eax, edx;
> - int err, index, attr_no;
> + int err, index, attr_no, tjmax;
>
> /*
> * Find attr number for sysfs:
> @@ -485,7 +505,7 @@ static int create_core_data(struct platform_device *pdev, unsigned int cpu,
> goto exit_free;
>
> /* We can access status register. Get Critical Temperature */
> - tdata->tjmax = get_tjmax(c, cpu, &pdev->dev);
> + tjmax = get_tjmax(tdata, &pdev->dev);
>
> /*
> * Read the still undocumented bits 8:15 of IA32_TEMPERATURE_TARGET.
> @@ -497,7 +517,7 @@ static int create_core_data(struct platform_device *pdev, unsigned int cpu,
> &eax, &edx);
> if (!err) {
> tdata->ttarget
> - = tdata->tjmax - ((eax >> 8) & 0xff) * 1000;
> + = tjmax - ((eax >> 8) & 0xff) * 1000;
> tdata->attr_size++;
> }
> }
