On Fri, Sep 30, 2016 at 1:10 PM, Vishal Verma <vishal.l.verma@xxxxxxxxx> wrote:
> Starting a full Address Range Scrub (ARS) on hitting a memory error
> machine check exception may not always be desirable. Provide a way
> through sysfs to toggle the behavior between just adding the address
> (cache line) where the MCE happened to the poison list and doing a full
> scrub. The former (selective insertion of the address) is done
> unconditionally.
>
> Cc: linux-acpi@xxxxxxxxxxxxxxx
> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> Cc: Linda Knippers <linda.knippers@xxxxxxx>
> Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> Signed-off-by: Vishal Verma <vishal.l.verma@xxxxxxxxx>
> ---
> drivers/acpi/nfit/core.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
> drivers/acpi/nfit/mce.c | 24 ++++++++++++++++-----
> drivers/acpi/nfit/nfit.h | 6 ++++++
> 3 files changed, 79 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
> index 80cc7c0..6a12bc2 100644
> --- a/drivers/acpi/nfit/core.c
> +++ b/drivers/acpi/nfit/core.c
> @@ -878,6 +878,58 @@ static ssize_t revision_show(struct device *dev,
> }
> static DEVICE_ATTR_RO(revision);
>
> +static ssize_t hw_error_scrub_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
> + struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
> + struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
> +
> + return sprintf(buf, "%d\n", acpi_desc->scrub_mode);
> +}
> +
> +/*
> + * The 'hw_error_scrub' attribute can have the following values written to it:
> + * '1': Enable a full scrub to happen if an exception for a memory error is
> + * received.
> + * '2': Switch to the default mode where an exception will only insert
> + * the address of the memory error into the poison and badblocks lists.
Should the default be zero instead of 2, to match what ->scrub_mode is
initialized to by default?
> + */
> +static ssize_t hw_error_scrub_store(struct device *dev,
> + struct device_attribute *attr, const char *buf, size_t size)
> +{
> + struct nvdimm_bus_descriptor *nd_desc;
> + ssize_t rc;
> + long val;
> +
> + rc = kstrtol(buf, 0, &val);
> + if (rc)
> + return rc;
> +
> + device_lock(dev);
> + nd_desc = dev_get_drvdata(dev);
> + if (nd_desc) {
> + struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
> +
> + switch (val) {
> + case MCE_SCRUB_ON:
> + acpi_desc->scrub_mode = MCE_SCRUB_ON;
If we're calling the sysfs attribute "hw_error_scrub" to avoid the
x86-specific MCE naming, I think we should call these defines
HW_ERROR_SCRUB_*.
> + break;
> + case MCE_SCRUB_OFF:
> + acpi_desc->scrub_mode = MCE_SCRUB_OFF;
> + break;
> + default:
> + rc = -EINVAL;
> + break;
> + }
> + }
> + device_unlock(dev);
> + if (rc)
> + return rc;
> + return size;
> +}
> +static DEVICE_ATTR_RW(hw_error_scrub);
> +
> /*
> * This shows the number of full Address Range Scrubs that have been
> * completed since driver load time. Userspace can wait on this using
> @@ -950,6 +1002,7 @@ static umode_t nfit_visible(struct kobject *kobj, struct attribute *a, int n)
> static struct attribute *acpi_nfit_attributes[] = {
> &dev_attr_revision.attr,
> &dev_attr_scrub.attr,
> + &dev_attr_hw_error_scrub.attr,
> NULL,
> };
>
> @@ -2489,6 +2542,7 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
> goto out_unlock;
> }
>
> + acpi_desc->scrub_mode = MCE_SCRUB_OFF;
If we make HW_ERROR_SCRUB_OFF == 0, then we don't need this line.
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