[Crash-utility] [PATCH] sial: Fix processing of bitfields on bigendian systems

[Dave Anderson]

----- "Michael Holzheu" <holzheu at linux.vnet.ibm.com> wrote:

> Hi Dave,
> 
> Here comes the patch!
> 
> For the future: Do you always want the patches as attachments and not
> inline?
> 
> Michael

Either way's fine, although I guess I prefer attachments.  I just didn't
want to pick apart Luc's email message given that the patch was
part of a forwarded inclusion.

Thanks,
  Dave


> 
> Am Mittwoch, den 16.09.2009, 16:55 -0400 schrieb Dave Anderson:
> > ----- "Luc Chouinard" <Luc.Chouinard at trueposition.com> wrote:
> > 
> > > ACK - and thanks!
> > 
> > Can you attach an actual patch that I can download and apply?
> > 
> > Thanks,
> >   Dave
> > 
> > > 
> > > > -----Original Message-----
> > > > From: crash-utility-bounces at redhat.com [mailto:crash-utility-
> > > > bounces at redhat.com] On Behalf Of Michael Holzheu
> > > > Sent: Wednesday, September 16, 2009 1:45 PM
> > > > To: Chouinard, Luc
> > > > Cc: wein at de.ibm.com; crash
> > > > Subject: [Crash-utility] [PATCH] sial: Fix processing of
> bitfields
> > > on
> > > > bigendian systems
> > > > 
> > > > Hi Luc,
> > > > 
> > > > The processing of bit fields on big endian systems in sial is
> > > currently
> > > > broken, because the bits are not copied to the correct position
> and
> > > are
> > > > not shifted the right way.
> > > > 
> > > > To fix this, the following patch does the processing on big
> endian
> > > > systems as follows:
> > > > 1. sial_exemem(): Copy complete bit field to the "end" (right)
> of
> > > the
> > > >    long long variable.
> > > > 2. get_bit_value(): Shift the bits of the bit field member right
> to
> > > >    the "end" of the long long variable. This results in the
> value
> > > of
> > > >    the requested bitfield member.
> > > > 
> > > > Michael
> > > > ---
> > > >  extensions/libsial/sial_member.c |    7 +++++--
> > > >  extensions/libsial/sial_type.c   |    6 +++++-
> > > >  2 files changed, 10 insertions(+), 3 deletions(-)
> > > > 
> > > > Index: crash-4.0.9/extensions/libsial/sial_member.c
> > > >
> ===================================================================
> > > > --- crash-4.0.9.orig/extensions/libsial/sial_member.c
> > > > +++ crash-4.0.9/extensions/libsial/sial_member.c
> > > > @@ -236,10 +236,13 @@ srcpos_t p;
> > > >  		}
> > > >  		/* bit field gymnastic */
> > > >  		else if(stm->m.nbits) {
> > > > -
> > > >  			ull value=0;
> > > > +			void *target = &value;
> > > > +
> > > > +			if (__BYTE_ORDER != __LITTLE_ENDIAN)
> > > > +				target = target + (sizeof(value) -
> > > stm->m.size);
> > > > 
> > > > -			API_GETMEM(m->mem+stm->m.offset, &value,
> > > stm->m.size);
> > > > +			API_GETMEM(m->mem+stm->m.offset, target,
> > > stm->m.size);
> > > >  			get_bit_value(value, stm->m.nbits, stm->m.fbit,
> > > stm-
> > > > >m.size, v);
> > > >  			/* no mempos for bit fields ... */
> > > > 
> > > > Index: crash-4.0.9/extensions/libsial/sial_type.c
> > > >
> ===================================================================
> > > > --- crash-4.0.9.orig/extensions/libsial/sial_type.c
> > > > +++ crash-4.0.9/extensions/libsial/sial_type.c
> > > > @@ -287,7 +287,11 @@ get_bit_value(ull val, int nbits, int bo
> > > >          else {
> > > >                  mask = ((1 << nbits) - 1);
> > > >          }
> > > > -        val = val >> boff;
> > > > +
> > > > +	if (__BYTE_ORDER == __LITTLE_ENDIAN)
> > > > +		val = val >> boff;
> > > > +	else
> > > > +		val = val >> (vnbits - boff - nbits);
> > > >  	val &= mask;
> > > > 
> > > >  	if(issigned(v)) {
> > > > 
> > > > 
> > > > --
> > > > Crash-utility mailing list
> > > > Crash-utility at redhat.com
> > > > https://www.redhat.com/mailman/listinfo/crash-utility
> > > 
> > > 
> > > 
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