Re: [PATCH] acpi: Fix hed module initialization order when it is built-in

[Xiaofei Tan]

Hi Mauro,

在 2024/12/12 0:22, Mauro Carvalho Chehab 写道:
> Em Fri, 15 Nov 2024 11:50:14 +0800
> Xiaofei Tan <tanxiaofei@xxxxxxxxxx> escreveu:
>
> Please always copy my @kernel.org address for upstream work.

OK

> > When the module hed is built-in, the init order is determined by
> > Makefile order. That order violates expectations. Because the module
> > hed init is behind evged. RAS records can't be handled in the
> > special time window that evged has initialized while hed not.
> > If the number of such RAS records is more than the APEI HEST error
> > source number, the HEST resources could be occupied all, and then
> > could affect subsequent RAS error reporting.
> IMO, it is a lot better to use a late init call. Please see:
> 	include/linux/init.h
>
> This would be done by, for instance, using late_initcall().
>
> Now, what we have is:
>
> 	acpi-y                          += evged.o
> 	obj-$(CONFIG_ACPI_HED)          += hed.o
>
> Where ACPI_HED being a tri-state.
>
> It sounds to me, that even, with your patch, if you build
> HED as a module, you'll still have a problem.
Yes, and it is also  affected by loading sequence of HED and GHES. Anyway, the risk remains.
> Shouldn't be ACPI_HED be changed from tristate to bool?

agree,

@Rafael

Hi Rafael, Please help check if we can do this change, thanks.


> Regards,
> Mauro
>
> > Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> > Signed-off-by: Xiaofei Tan <tanxiaofei@xxxxxxxxxx>
> > ---
> >   drivers/acpi/Makefile | 8 +++++++-
> >   1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> > index 61ca4afe83dc..54f60b7922ad 100644
> > --- a/drivers/acpi/Makefile
> > +++ b/drivers/acpi/Makefile
> > @@ -15,6 +15,13 @@ endif
> >   
> >   obj-$(CONFIG_ACPI)		+= tables.o
> >   
> > +#
> > +# The hed.o needs to be in front of evged.o to avoid the problem that
> > +# RAS errors cannot be handled in the special time window of startup
> > +# phase that evged has initialized while hed not.
> > +#
> > +obj-$(CONFIG_ACPI_HED)		+= hed.o
> > +
> >   #
> >   # ACPI Core Subsystem (Interpreter)
> >   #
> > @@ -95,7 +102,6 @@ obj-$(CONFIG_ACPI_HOTPLUG_IOAPIC) += ioapic.o
> >   obj-$(CONFIG_ACPI_BATTERY)	+= battery.o
> >   obj-$(CONFIG_ACPI_SBS)		+= sbshc.o
> >   obj-$(CONFIG_ACPI_SBS)		+= sbs.o
> > -obj-$(CONFIG_ACPI_HED)		+= hed.o
> >   obj-$(CONFIG_ACPI_EC_DEBUGFS)	+= ec_sys.o
> >   obj-$(CONFIG_ACPI_BGRT)		+= bgrt.o
> >   obj-$(CONFIG_ACPI_CPPC_LIB)	+= cppc_acpi.o
> .