Re: [PATCH v2 0/5] tpm_tis: fix interrupts (again)

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James Bottomley @ 2020-10-15 11:57 MST:

> On Thu, 2020-10-15 at 11:48 -0700, Jerry Snitselaar wrote:
>> James Bottomley @ 2020-10-15 08:36 MST:
>> 
>> > On Wed, 2020-10-14 at 13:58 -0700, Jerry Snitselaar wrote:
>> > > Hans de Goede @ 2020-10-14 09:46 MST:
>> > > 
>> > > > Hi,
>> > > > 
>> > > > On 10/14/20 6:34 PM, Jerry Snitselaar wrote:
>> > > > > Hans de Goede @ 2020-10-14 09:04 MST:
>> > > > > 
>> > > > > > Hi,
>> > > > > > 
>> > > > > > On 10/14/20 5:23 PM, James Bottomley wrote:
>> > > > > > > On Wed, 2020-10-14 at 17:03 +0200, Hans de Goede wrote:
>> > > > > > > > On 10/13/20 6:05 PM, Jerry Snitselaar wrote:
>> > > > > > > > > James Bottomley @ 2020-10-13 08:24 MST:
>> > > > > > > > > > On Tue, 2020-10-13 at 08:15 -0700, Jerry Snitselaar
>> > > > > > > > > > wrote:
>> > > > > > > > > > > Jarkko Sakkinen @ 2020-10-12 18:17 MST:
>> > > > > > > [...]
>> > > > > > > > > > > >     Jerry, once you have some bandwidth (no
>> > > > > > > > > > > > rush,
>> > > > > > > > > > > > does not land
>> > > > > > > > > > > > before rc2), it would be great that if you
>> > > > > > > > > > > > could
>> > > > > > > > > > > > try this.
>> > > > > > > > > > > > I'm emphasizing this just because of the
>> > > > > > > > > > > > intersection. I
>> > > > > > > > > > > > think it would also make senset to get tested-
>> > > > > > > > > > > > by
>> > > > > > > > > > > > from Nayna.
>> > > > > > > > > > > 
>> > > > > > > > > > > I will run some tests on some other systems I
>> > > > > > > > > > > have
>> > > > > > > > > > > access to.
>> > > > > > > > > > > As noted in the other email I did a quick test
>> > > > > > > > > > > with a
>> > > > > > > > > > > t490s
>> > > > > > > > > > > with an older bios that exhibits the problem
>> > > > > > > > > > > originally
>> > > > > > > > > > > reported when Stefan's patch enabled interrupts.
>> > > > > > > > > > 
>> > > > > > > > > > Well, it means there's still some other problem.  I
>> > > > > > > > > > was
>> > > > > > > > > > hoping
>> > > > > > > > > > that because the rainbow pass system originally
>> > > > > > > > > > exhibited the
>> > > > > > > > > > same symptoms (interrupt storm) fixing it would
>> > > > > > > > > > also
>> > > > > > > > > > fix the t490
>> > > > > > > > > > and the ineffective EOI bug looked like a great
>> > > > > > > > > > candidate for
>> > > > > > > > > > being the root cause.
>> > > > > > > > > > 
>> > > > > > > > > 
>> > > > > > > > > Adding Hans to the list.
>> > > > > > > > > 
>> > > > > > > > > IIUC in the t490s case the problem lies with the
>> > > > > > > > > hardware
>> > > > > > > > > itself.
>> > > > > > > > > Hans, is that correct?
>> > > > > > > > 
>> > > > > > > > More or less. AFAIK / have been told by Lenovo it is an
>> > > > > > > > issue with
>> > > > > > > > the configuration of the inerrupt-type of the GPIO pin
>> > > > > > > > used
>> > > > > > > > for the
>> > > > > > > > IRQ, which is a firmware issue which could be fixed by
>> > > > > > > > a
>> > > > > > > > BIOS update
>> > > > > > > > (the pin is setup as a direct-irq pin for the APIC, so
>> > > > > > > > the
>> > > > > > > > OS has no
>> > > > > > > > control of the IRQ type since with APIC irqs this is
>> > > > > > > > all
>> > > > > > > > supposed to
>> > > > > > > > be setup properly before hand).
>> > > > > > > > 
>> > > > > > > > But it is a model specific issue, if we denylist IRQ
>> > > > > > > > usage
>> > > > > > > > on this
>> > > > > > > > Lenovo model (and probably a few others) then we should
>> > > > > > > > be
>> > > > > > > > able to
>> > > > > > > > restore the IRQ code to normal functionality for all
>> > > > > > > > other
>> > > > > > > > device
>> > > > > > > > models which declare an IRQ in their resource tables.
>> > > > > > > I can do that with a quirk, but how do I identify the
>> > > > > > > device?  TPM
>> > > > > > > manufacturer and version? or do I have to use something
>> > > > > > > like
>> > > > > > > the ACPI
>> > > > > > > bios version?
>> > > > > > 
>> > > > > > I'm not sure if the TPM ids are unique to one model/series
>> > > > > > of
>> > > > > > laptops.
>> > > > > > 
>> > > > > > So my idea for this was to match on DMI strings,
>> > > > > > specifically
>> > > > > > use a DMI match on the DMI_SYS_VENDOR and
>> > > > > > DMI_PRODUCT_VERSION
>> > > > > > strings (normally one would use DMI_PRODUCT_NAME but for
>> > > > > > Lenovo
>> > > > > > devices the string which you expect to be in
>> > > > > > DMI_PRODUCT_NAME
>> > > > > > is actually in DMI_PRODUCT_VERSION).
>> > > > > > 
>> > > > > > You can easily get the strings for your device by doing:
>> > > > > > 
>> > > > > > cat /sys/class/dmi/id/sys_vendor
>> > > > > > cat /sys/class/dmi/id/product_version
>> > > > > > 
>> > > > > > Regards,
>> > > > > > 
>> > > > > > Hans
>> > > > > Plus use dmi_get_date(DMI_BIOS_DATE,...) to check
>> > > > > if the bios is older than the fixed bios? Has Lenovo
>> > > > > released the fixed bios?
>> > > > 
>> > > > Maybe, the fixed BIOS-es which I have seen (for the X1C8,
>> > > > broken BIOS was a pre-production BIOS) "fixed" this by
>> > > > no longer listing an IRQ in the ACPI resources for the TPM.
>> > > > 
>> > > > Which means that the new BIOS still being on the deny list
>> > > > does not matter since the IRQ support won't work anyways as
>> > > > we no longer get an IRQ assigned.
>> > > > 
>> > > > So I don't think this is necessary and it will just complicate
>> > > > things unnecessarily. This whole saga has already taken way
>> > > > too long to fix. So IMHO the simplest fix where we just deny
>> > > > list the broken models independent of BIOS versions and move
>> > > > on seems best.
>> > > > 
>> > > > Regards,
>> > > > 
>> > > > Hans
>> > > 
>> > > This worked for me:
>> > > 
>> > > diff --git a/drivers/char/tpm/tpm_tis.c
>> > > b/drivers/char/tpm/tpm_tis.c
>> > > index 0b214963539d..abe674d1de6d 100644
>> > > --- a/drivers/char/tpm/tpm_tis.c
>> > > +++ b/drivers/char/tpm/tpm_tis.c
>> > > @@ -27,6 +27,7 @@
>> > >  #include <linux/of.h>
>> > >  #include <linux/of_device.h>
>> > >  #include <linux/kernel.h>
>> > > +#include <linux/dmi.h>
>> > >  #include "tpm.h"
>> > >  #include "tpm_tis_core.h"
>> > > 
>> > > @@ -63,6 +64,26 @@ module_param(force, bool, 0444);
>> > >  MODULE_PARM_DESC(force, "Force device probe rather than using
>> > > ACPI
>> > > entry");
>> > >  #endif
>> > > 
>> > > +static int tpm_tis_disable_irq(const struct dmi_system_id *d)
>> > > +{
>> > > +       pr_notice("tpm_tis: %s detected: disabling
>> > > interrupts.\n", d-
>> > > > ident);
>> > > +       interrupts = false;
>> > > +
>> > > +       return 0;
>> > > +}
>> > > +
>> > > +static const struct dmi_system_id tpm_tis_dmi_table[] = {
>> > > +       {
>> > > +               .callback = tpm_tis_disable_irq,
>> > > +               .ident = "ThinkPad T490s",
>> > > +               .matches = {
>> > > +                       DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
>> > > +                       DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad
>> > > T490s"),
>> > > +               },
>> > > +       },
>> > > +       {}
>> > > +};
>> > > +
>> > >  #if defined(CONFIG_PNP) && defined(CONFIG_ACPI)
>> > >  static int has_hid(struct acpi_device *dev, const char *hid)
>> > >  {
>> > > @@ -192,6 +213,8 @@ static int tpm_tis_init(struct device *dev,
>> > > struct tpm_info *tpm_info)
>> > >         int irq = -1;
>> > >         int rc;
>> > > 
>> > > +       dmi_check_system(tpm_tis_dmi_table);
>> > > +
>> > >         rc = check_acpi_tpm2(dev);
>> > >         if (rc)
>> > >                 return rc;
>> > 
>> > This looks OK to me with the caveat that anyone on one of these
>> > systems
>> > has no way to enable interrupts again if they think they have a
>> > fixed
>> > bios.  What about making interrupts a tristate with the default
>> > value
>> > -1?  Then in the dmi check, if we see -1 we set it to 0 but if we
>> > see 1
>> > (the user has specified interrupts=1 on the module insert line) we
>> > leave it?
>> > 
>> > James
>> 
>> like this?
>
> Yes, that works, I think.
>
> Reviewed-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
>
> James
>

I'll send a real patch in a just a bit. The pr_notice needs to move into the
if block, otherwise it will log that it is disabling interrupts when the
user has forced enabling.

Regards,
Jerry

>
>> diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
>> index 0b214963539d..10c46cb26c5a 100644
>> --- a/drivers/char/tpm/tpm_tis.c
>> +++ b/drivers/char/tpm/tpm_tis.c
>> @@ -27,6 +27,7 @@
>>  #include <linux/of.h>
>>  #include <linux/of_device.h>
>>  #include <linux/kernel.h>
>> +#include <linux/dmi.h>
>>  #include "tpm.h"
>>  #include "tpm_tis_core.h"
>> 
>> @@ -49,8 +50,8 @@ static inline struct tpm_tis_tcg_phy
>> *to_tpm_tis_tcg_phy(struct tpm_tis_data *da
>>         return container_of(data, struct tpm_tis_tcg_phy, priv);
>>  }
>> 
>> -static bool interrupts = true;
>> -module_param(interrupts, bool, 0444);
>> +static int interrupts = -1;
>> +module_param(interrupts, int, 0444);
>>  MODULE_PARM_DESC(interrupts, "Enable interrupts");
>> 
>>  static bool itpm;
>> @@ -63,6 +64,27 @@ module_param(force, bool, 0444);
>>  MODULE_PARM_DESC(force, "Force device probe rather than using ACPI
>> entry");
>>  #endif
>> 
>> +static int tpm_tis_disable_irq(const struct dmi_system_id *d)
>> +{
>> +       pr_notice("tpm_tis: %s detected: disabling interrupts.\n", d-
>> >ident);
>> +       if (interrupts == -1)
>> +               interrupts = 0;
>> +
>> +       return 0;
>> +}
>> +
>> +static const struct dmi_system_id tpm_tis_dmi_table[] = {
>> +       {
>> +               .callback = tpm_tis_disable_irq,
>> +               .ident = "ThinkPad T490s",
>> +               .matches = {
>> +                       DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
>> +                       DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad
>> T490s"),
>> +               },
>> +       },
>> +       {}
>> +};
>> +
>>  #if defined(CONFIG_PNP) && defined(CONFIG_ACPI)
>>  static int has_hid(struct acpi_device *dev, const char *hid)
>>  {
>> @@ -192,6 +214,8 @@ static int tpm_tis_init(struct device *dev,
>> struct tpm_info *tpm_info)
>>         int irq = -1;
>>         int rc;
>> 
>> +       dmi_check_system(tpm_tis_dmi_table);
>> +
>>         rc = check_acpi_tpm2(dev);
>>         if (rc)
>>                 return rc;
>> 




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