RE: [PATCH] pinctrl: Don't allow PINCTRL_AMD to be a module

["Limonciello, Mario" <Mario.Limonciello@xxxxxxx>]

[Public]



> -----Original Message-----
> From: Hans de Goede <hdegoede@xxxxxxxxxx>
> Sent: Wednesday, July 13, 2022 16:25
> To: Limonciello, Mario <Mario.Limonciello@xxxxxxx>; Linus Walleij
> <linus.walleij@xxxxxxxxxx>
> Cc: Natikar, Basavaraj <Basavaraj.Natikar@xxxxxxx>; madcatx@xxxxxxxx;
> jwrdegoede@xxxxxxxxxxxxxxxxx; linux-gpio@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] pinctrl: Don't allow PINCTRL_AMD to be a module
> 
> Hi,
> 
> On 7/13/22 19:59, Mario Limonciello wrote:
> > It was observed that by allowing pinctrl_amd to be loaded
> > later in the boot process that interrupts sent to the GPIO
> > controller early in the boot are not serviced.  The kernel treats
> > these as a spurious IRQ and disables the IRQ.
> >
> > This problem was exacerbated because it happened on a system with
> > an encrypted partition so the kernel object was not accesssible for
> > an extended period of time while waiting for a passphrase.
> >
> > To avoid this situation from occurring, stop allowing pinctrl-amd
> > from being built as a module and instead require it to be built-in
> > or disabled.
> >
> > Reported-by: madcatx@xxxxxxxx
> > Suggested-by: jwrdegoede@xxxxxxxxxxxxxxxxx
> 
> Note I generally use: "Hans de Goede <hdegoede@xxxxxxxxxx>" for all
> things kernel related.

Sorry about that, I just took the email from Kernel Bugzilla when I copied/pasted
and didn't realize they were different.
Will try to remember that for the future.

> 
> This looks good to me. Fedora is already building in amd-pinctrl
> which AFAIK is done because of similar issues to the reason given
> in the commit message:
> 
> Acked-by: Hans de Goede <hdegoede@xxxxxxxxxx>

Thanks!

FWIW I poked around and at least Ubuntu and RHEL are both enabling it
as built in as well, presumably big distros setting this up by default may be
why this issue hasn't been very widespread.

Linus W,
BTW I do have a suspicion that this might be the same root cause as
https://bugzilla.kernel.org/show_bug.cgi?id=201817
but we'll need someone from that bug report to chime in to confirm.

> 
> Regards,
> 
> Hans
> 
> 
> 
> > Link:
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugz
> illa.kernel.org%2Fshow_bug.cgi%3Fid%3D216230&amp;data=05%7C01%7Cm
> ario.limonciello%40amd.com%7Cc28ab57936e1427e7a7a08da65162319%7C3d
> d8961fe4884e608e11a82d994e183d%7C0%7C0%7C637933443003195561%7CU
> nknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI
> 6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=XJB0L03z%2
> B3mVBZxdlX6q6MBanZQwymoQSwlmMCrPjcs%3D&amp;reserved=0
> > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> > ---
> >  drivers/pinctrl/Kconfig | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
> > index f52960d2dfbe..bff144c97e66 100644
> > --- a/drivers/pinctrl/Kconfig
> > +++ b/drivers/pinctrl/Kconfig
> > @@ -32,7 +32,7 @@ config DEBUG_PINCTRL
> >  	  Say Y here to add some extra checks and diagnostics to PINCTRL
> calls.
> >
> >  config PINCTRL_AMD
> > -	tristate "AMD GPIO pin control"
> > +	bool "AMD GPIO pin control"
> >  	depends on HAS_IOMEM
> >  	depends on ACPI || COMPILE_TEST
> >  	select GPIOLIB