[PATCH v2] ocxl: Fix endiannes bug in read_afu_name()
Greg Kurz
groug at kaod.org
Fri Dec 21 01:53:04 AEDT 2018
On Wed, 12 Dec 2018 13:26:10 +1100
Andrew Donnellan <andrew.donnellan at au1.ibm.com> wrote:
> On 12/12/18 4:58 am, Greg Kurz wrote:
> > The AFU Descriptor Template in the PCI config space has a Name Space
> > field which is a 24 Byte ASCII character string of descriptive name
> > space for the AFU. The OCXL driver read the string four characters at
> > a time with pci_read_config_dword().
> >
> > This optimization is valid on a little-endian system since this is PCI,
> > but a big-endian system ends up with each subset of four characters in
> > reverse order.
> >
> > This could be fixed by switching to read characters one by one. Another
> > option is to swap the bytes if we're big-endian.
> >
> > Go for the latter with le32_to_cpu().
> >
> > Cc: stable at vger.kernel.org # v4.16
> > Signed-off-by: Greg Kurz <groug at kaod.org>
> > Acked-by: Frederic Barrat <fbarrat at linux.ibm.com>
>
> Acked-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>
>
Friendly ping before Xmas break :)
> > ---
> > v2: - silence sparse with (__force __le32) cast
> > - new changelog
> > ---
> > drivers/misc/ocxl/config.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/misc/ocxl/config.c b/drivers/misc/ocxl/config.c
> > index 57a6bb1fd3c9..8f2c5d8bd2ee 100644
> > --- a/drivers/misc/ocxl/config.c
> > +++ b/drivers/misc/ocxl/config.c
> > @@ -318,7 +318,7 @@ static int read_afu_name(struct pci_dev *dev, struct ocxl_fn_config *fn,
> > if (rc)
> > return rc;
> > ptr = (u32 *) &afu->name[i];
> > - *ptr = val;
> > + *ptr = le32_to_cpu((__force __le32) val);
> > }
> > afu->name[OCXL_AFU_NAME_SZ - 1] = '\0'; /* play safe */
> > return 0;
> >
>
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