On Sat, Jun 06, 2020 at 06:04:11PM +0530, Vaibhav Jain wrote:
> >> + /* update health struct with various flags derived from health bitmap */
> >> + health = (struct nd_papr_pdsm_health) {
> >> + .dimm_unarmed = p->health_bitmap & PAPR_PMEM_UNARMED_MASK,
> >> + .dimm_bad_shutdown = p->health_bitmap &
> >> PAPR_PMEM_BAD_SHUTDOWN_MASK,
> >> + .dimm_bad_restore = p->health_bitmap &
> >> PAPR_PMEM_BAD_RESTORE_MASK,
> >> + .dimm_encrypted = p->health_bitmap & PAPR_PMEM_ENCRYPTED,
> >> + .dimm_locked = p->health_bitmap & PAPR_PMEM_SCRUBBED_AND_LOCKED,
> >> + .dimm_scrubbed = p->health_bitmap &
> >> PAPR_PMEM_SCRUBBED_AND_LOCKED,
> >
> > Are you sure these work? These are not assignments to a bool so I don't
> > think
> > gcc will do what you want here.
> Yeah, somehow this slipped by and didnt show up in my tests. I checked
> the assembly dump and seems GCC was silently skipping initializing these
> fields without making any noise.
It's not "skipping" that, it initialises the field to 0, just like your
code said it should :-)
If you think GCC should warn for this, please open a PR? It is *normal*
for bit-fields to be truncated from what is assigned to it, but maybe we
could warn for it in the 1-bit case (we currently don't seem to, even
when the bit-field type is _Bool).
Thanks,
Segher
