Re: [PATCH v1 1/1] pc-bios/s390-ccw: fix sclp_get_loadparm_ascii

[Cornelia Huck <cohuck@redhat.com>]

On Thu, 28 Nov 2019 13:35:29 +0100
Christian Borntraeger <borntraeger@de.ibm.com> wrote:

> Ack.
> 
> Conny, I think this would be really nice to have for 4.2 (together with a bios rebuild)
> as this fixes a regression. Opinions?

I fear that this is a bit late for 4.2... but this should get a
cc:stable.

> 
> 
> 
> On 28.11.19 13:33, Claudio Imbrenda wrote:
> > The existing s390 bios gets the LOADPARM information from the system using
> > an SCLP call that specifies a buffer length too small to contain all the
> > output.
> > 
> > The recent fixes in the SCLP code have exposed this bug, since now the
> > SCLP call will return an error (as per architecture) instead of
> > writing partially and completing successfully.
> > 
> > The solution is simply to specify the full page length as the SCCB
> > length instead of a smaller size.
> > 
> > Fixes: 832be0d8a3bb ("s390x: sclp: Report insufficient SCCB length")
> > Fixes: 9a22473c70f3 ("pc-bios/s390-ccw: get LOADPARM stored in SCP Read Info")
> > 
> > Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> > ---
> >  pc-bios/s390-ccw/sclp.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/pc-bios/s390-ccw/sclp.c b/pc-bios/s390-ccw/sclp.c
> > index c0223fa..7251f9a 100644
> > --- a/pc-bios/s390-ccw/sclp.c
> > +++ b/pc-bios/s390-ccw/sclp.c
> > @@ -112,7 +112,7 @@ void sclp_get_loadparm_ascii(char *loadparm)
> >      ReadInfo *sccb = (void *)_sccb;
> >  
> >      memset((char *)_sccb, 0, sizeof(ReadInfo));
> > -    sccb->h.length = sizeof(ReadInfo);
> > +    sccb->h.length = SCCB_SIZE;
> >      if (!sclp_service_call(SCLP_CMDW_READ_SCP_INFO, sccb)) {
> >          ebcdic_to_ascii((char *) sccb->loadparm, loadparm, LOADPARM_LEN);
> >      }
> >   

The change seems sane.