Re: [PATCH v2 1/4] tpm: Add explicit endianness cast

From: Jason Gunthorpe
Date: Tue Apr 17 2018 - 10:00:23 EST


On Tue, Apr 17, 2018 at 08:32:33AM +0000, Thiebaud Weksteen wrote:
> On Tue, Apr 17, 2018 at 5:02 AM Jason Gunthorpe <jgg@xxxxxxxx> wrote:
>
> > On Thu, Apr 12, 2018 at 12:13:47PM +0200, Thiebaud Weksteen wrote:
> > > Signed-off-by: Thiebaud Weksteen <tweek@xxxxxxxxxx>
> > > drivers/char/tpm/tpm_eventlog_of.c | 4 ++--
> > > 1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/char/tpm/tpm_eventlog_of.c
> b/drivers/char/tpm/tpm_eventlog_of.c
> > > index 96fd5646f866..d74568d58a66 100644
> > > +++ b/drivers/char/tpm/tpm_eventlog_of.c
> > > @@ -56,8 +56,8 @@ int tpm_read_log_of(struct tpm_chip *chip)
> > > * but physical tpm needs the conversion.
> > > */
> > > if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0) {
> > > - size = be32_to_cpup(sizep);
> > > - base = be64_to_cpup(basep);
> > > + size = be32_to_cpup((__be32 *)sizep);
> > > + base = be64_to_cpup((__be64 *)basep);
>
> > Er, no.. change the definitions of sizep and basep to be __be
>
> > Jason
>
> Please read the comment before the condition. sizep and
> basep may contain either little endian or big endian and this block is used
> to adjust that. Let me know if there is a better way for handling this.

Well a cast like that will throw sparse warnings, you need __force at
least

Jason