The test suite for libosmocore fails on big-endian architectures

This is merely a historical archive of years 2008-2021, before the migration to mailman3.

A maintained and still updated list archive can be found at https://lists.osmocom.org/hyperkitty/list/OpenBSC@lists.osmocom.org/.

Jaroslav Skarvada jskarvad at redhat.com
Wed Dec 9 18:26:41 UTC 2015


I am afraid using bitfields is not portable and bits ordering
may differ between architectures and compilers (it's not only
about endianess, IMHO it's not defined by the standard).
I think correct portable implementation should use macros and
bitmasks, maybe something to consider for future updates

thanks & regards

Jaroslav

----- Original Message -----
> Thanks,
> 
> this works for me, but I still don't understand why, the ordering
> of bitfields looks quite strange to me :)
> 
> Jaroslav
> 
> ----- Original Message -----
> > Hi,
> > 
> > In the end, I ended up with the following patch that works:
> > 
> > diff --git a/include/osmocom/gsm/protocol/gsm_03_41.h
> > b/include/osmocom/gsm/protocol/gsm_03_41.h
> > index 0ece6cc..40051cd 100644
> > --- a/include/osmocom/gsm/protocol/gsm_03_41.h
> > +++ b/include/osmocom/gsm/protocol/gsm_03_41.h
> > @@ -2,8 +2,13 @@
> > 
> >  #include <stdint.h>
> > 
> > +#include <osmocom/core/endian.h>
> >  #include <osmocom/gsm/protocol/gsm_04_12.h>
> > 
> > +#ifndef OSMO_IS_LITTLE_ENDIAN
> > + #define OSMO_IS_LITTLE_ENDIAN 0
> > +#endif
> > +
> >  /* GSM TS 03.41 definitions also TS 23.041*/
> > 
> >  #define GSM341_MAX_PAYLOAD (GSM412_MSG_LEN-sizeof(struct
> >  gsm341_ms_message))
> > @@ -13,19 +18,36 @@
> >  /* Chapter 9.3.2 */
> >  struct gsm341_ms_message {
> >   struct {
> > +#if OSMO_IS_LITTLE_ENDIAN == 1
> >   uint8_t code_hi:6;
> >   uint8_t gs:2;
> >   uint8_t update:4;
> >   uint8_t code_lo:4;
> > +#else
> > + uint8_t gs:2;
> > + uint8_t code_hi:6;
> > + uint8_t code_lo:4;
> > + uint8_t update:4;
> > +#endif
> >   } serial;
> >   uint16_t msg_id;
> >   struct {
> > +#if OSMO_IS_LITTLE_ENDIAN == 1
> >   uint8_t language:4;
> >   uint8_t group:4;
> > +#else
> > + uint8_t group:4;
> > + uint8_t language:4;
> > +#endif
> >   } dcs;
> >   struct {
> > +#if OSMO_IS_LITTLE_ENDIAN == 1
> >   uint8_t total:4;
> >   uint8_t current:4;
> > +#else
> > + uint8_t current:4;
> > + uint8_t total:4;
> > +#endif
> >   } page;
> >   uint8_t data[0];
> >  } __attribute__((packed));
> > @@ -33,12 +55,21 @@ struct gsm341_ms_message {
> >  /* Chapter 9.4.1.3 */
> >  struct gsm341_etws_message {
> >   struct {
> > +#if OSMO_IS_LITTLE_ENDIAN == 1
> >   uint8_t code_hi:4;
> >   uint8_t popup:1;
> >   uint8_t alert:1;
> >   uint8_t gs:2;
> >   uint8_t update:4;
> >   uint8_t code_lo:4;
> > +#else
> > + uint8_t gs:2;
> > + uint8_t alert:1;
> > + uint8_t popup:1;
> > + uint8_t code_hi:4;
> > + uint8_t code_lo:4;
> > + uint8_t update:4;
> > +#endif
> >   } serial;
> >   uint16_t msg_id;
> >   uint16_t warning_type;
> > 
> > 
> > Note that the order of the fields is a bit different than your proposal.
> > 
> > I also, interestingly enough, found this:
> >   http://lists.osmocom.org/pipermail/baseband-devel/2015-February/000021.html
> > 
> > It's from Februrary, and already a suggestion for a patch for this
> > problem. I don't think however that patch
> > will work with other big-endian architectures.
> > 
> > Cheers,
> > Ruben
> > 
> > 
> > 2015-12-07 22:16 GMT+01:00 Ruben Undheim <ruben.undheim at gmail.com>:
> > > Hi,
> > >
> > > Thanks!
> > >
> > > Apparently it doesn't work correctly, but I'm now trying with:
> > >   #if OSMO_IS_LITTLE_ENDIAN == 1
> > >
> > > instead, and I have big hopes.
> > >
> > > (OSMO_IS_LITTLE_ENDIAN is always defined, 1 for low-endian archs and 0
> > > for big-endian archs.)
> > >
> > > Cheers,
> > > Ruben
> > >
> > > 2015-12-06 22:15 GMT+01:00 Harald Welte <laforge at gnumonks.org>:
> > >> Hi Ruben,
> > >>
> > >> On Sun, Dec 06, 2015 at 04:53:09PM +0100, Ruben Undheim wrote:
> > >>> While building the package for Debian, apparently there is a problem
> > >>> related to big-endian architectures.
> > >>
> > >> While I still own several PPC machines, I haven't booted any of them in
> > >> years, and don't have a build setup ready.  Please try the patch
> > >> below and report back if it works.  If yes, we can merge it.
> > >>
> > >> From 51ae645e220556bbeabce3ac57304639328e2164 Mon Sep 17 00:00:00 2001
> > >> From: Harald Welte <laforge at gnumonks.org>
> > >> Date: Sun, 6 Dec 2015 22:12:43 +0100
> > >> Subject: [PATCH] untested fix for gsm_03_41.h and big-endian machines
> > >>
> > >> Our gsm_03_41 structs use bit-fields, but don't do the usual
> > >> little/big-endian jumping.
> > >> ---
> > >>  include/osmocom/gsm/protocol/gsm_03_41.h | 27
> > >>  +++++++++++++++++++++++++++
> > >>  1 file changed, 27 insertions(+)
> > >>
> > >> diff --git a/include/osmocom/gsm/protocol/gsm_03_41.h
> > >> b/include/osmocom/gsm/protocol/gsm_03_41.h
> > >> index 0ece6cc..f007cc1 100644
> > >> --- a/include/osmocom/gsm/protocol/gsm_03_41.h
> > >> +++ b/include/osmocom/gsm/protocol/gsm_03_41.h
> > >> @@ -2,6 +2,7 @@
> > >>
> > >>  #include <stdint.h>
> > >>
> > >> +#include <osmocom/core/endian.h>
> > >>  #include <osmocom/gsm/protocol/gsm_04_12.h>
> > >>
> > >>  /* GSM TS 03.41 definitions also TS 23.041*/
> > >> @@ -13,19 +14,36 @@
> > >>  /* Chapter 9.3.2 */
> > >>  struct gsm341_ms_message {
> > >>         struct {
> > >> +#ifdef OSMO_IS_LITTLE_ENDIAN
> > >>                 uint8_t code_hi:6;
> > >>                 uint8_t gs:2;
> > >>                 uint8_t update:4;
> > >>                 uint8_t code_lo:4;
> > >> +#else
> > >> +               uint8_t code_lo:4;
> > >> +               uint8_t update:4;
> > >> +               uint8_t gs:2;
> > >> +               uint8_t code_hi:6;
> > >> +#endif
> > >>         } serial;
> > >>         uint16_t msg_id;
> > >>         struct {
> > >> +#ifdef OSMO_IS_LITTLE_ENDIAN
> > >>                 uint8_t language:4;
> > >>                 uint8_t group:4;
> > >> +#else
> > >> +               uint8_t group:4;
> > >> +               uint8_t language:4;
> > >> +#endif
> > >>         } dcs;
> > >>         struct {
> > >> +#ifdef OSMO_IS_LITTLE_ENDIAN
> > >>                 uint8_t total:4;
> > >>                 uint8_t current:4;
> > >> +#else
> > >> +               uint8_t current:4;
> > >> +               uint8_t total:4;
> > >> +#endif
> > >>         } page;
> > >>         uint8_t data[0];
> > >>  } __attribute__((packed));
> > >> @@ -33,12 +51,21 @@ struct gsm341_ms_message {
> > >>  /* Chapter 9.4.1.3 */
> > >>  struct gsm341_etws_message {
> > >>         struct {
> > >> +#ifdef OSMO_IS_LITTLE_ENDIAN
> > >>                 uint8_t code_hi:4;
> > >>                 uint8_t popup:1;
> > >>                 uint8_t alert:1;
> > >>                 uint8_t gs:2;
> > >>                 uint8_t update:4;
> > >>                 uint8_t code_lo:4;
> > >> +#else
> > >> +               uint8_t code_lo:4;
> > >> +               uint8_t update:4;
> > >> +               uint8_t gs:2;
> > >> +               uint8_t alert:1;
> > >> +               uint8_t popup:1;
> > >> +               uint8_t code_hi:4;
> > >> +#endif
> > >>         } serial;
> > >>         uint16_t msg_id;
> > >>         uint16_t warning_type;
> > >> --
> > >> 2.6.2
> > >>
> > >> --
> > >> - Harald Welte <laforge at gnumonks.org>
> > >> http://laforge.gnumonks.org/
> > >> ============================================================================
> > >> "Privacy in residential applications is a desirable marketing option."
> > >>                                                   (ETSI EN 300 175-7 Ch.
> > >>                                                   A6)
> > 
> 



More information about the OpenBSC mailing list