Re: [PATCH] ACPI, APEI: Fixup incorrect 64-bit access width firmware bug

[Myron Stowe <mstowe@redhat.com>]

On Wed, 2013-01-16 at 23:54 +0100, Rafael J. Wysocki wrote:
> On Wednesday, January 16, 2013 05:03:29 PM Lans Zhang wrote:
> > The bit width check was introduced by 15afae60 (ACPI, APEI: Fix
> > incorrect APEI register bit width check and usage), and a fixup
> > for incorrect 32-bit width memory address was given by f712c71
> > (ACPI, APEI: Fixup common access width firmware bug). Now there
> > is a similar symptom:
> > 
> > [Firmware Bug]: APEI: Invalid bit width + offset in GAR [0x12345000/64/0/3/0]
> > 
> > Another bogus BIOS reports an incorrect 64-bit width in trigger table.
> > Thus, apply to a similar workaround for 64-bit width memory address.
> 
> This makes sense to me, but I'd like more people to have a look at it (Myron,
> Ying, Gary CCed).
> 
> Thanks,
> Rafael
> 
> 
> > Signed-off-by: Lans Zhang <jia.zhang@windriver.com>
> > ---
> >  drivers/acpi/apei/apei-base.c |    3 +++
> >  1 files changed, 3 insertions(+), 0 deletions(-)
> > 
> > diff --git a/drivers/acpi/apei/apei-base.c b/drivers/acpi/apei/apei-base.c
> > index 00a7836..46f80e2 100644
> > --- a/drivers/acpi/apei/apei-base.c
> > +++ b/drivers/acpi/apei/apei-base.c
> > @@ -590,6 +590,9 @@ static int apei_check_gar(struct acpi_generic_address *reg, u64 *paddr,
> >  	if (bit_width == 32 && bit_offset == 0 && (*paddr & 0x03) == 0 &&
> >  	    *access_bit_width < 32)
> >  		*access_bit_width = 32;
> > +	else if (bit_width == 64 && bit_offset == 0 && (*paddr & 0x07) == 0 &&
> > +	    *access_bit_width < 64)
> > +		*access_bit_width = 64;
> >  
> >  	if ((bit_width + bit_offset) > *access_bit_width) {
> >  		pr_warning(FW_BUG APEI_PFX
> > 

I don't see anything concerning (the spec was definitely anything less
than clear - at least to me - so I'm not surprised we are seeing so many
interpretations and/or bugs).

Acked-by: Myron Stowe <myron.stowe@redhat.com>