Re: [PATCH 1/9] drm/amd/pm: Annotate struct smu10_voltage_dependency_table with __counted_by

[Alex Deucher]

On Mon, Sep 25, 2023 at 10:07 AM Alex Deucher <alexdeucher@xxxxxxxxx> wrote:
>
> On Mon, Sep 25, 2023 at 2:30 AM Christian König
> <christian.koenig@xxxxxxx> wrote:
> >
> > Am 22.09.23 um 19:41 schrieb Alex Deucher:
> > > On Fri, Sep 22, 2023 at 1:32 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> > >> Prepare for the coming implementation by GCC and Clang of the __counted_by
> > >> attribute. Flexible array members annotated with __counted_by can have
> > >> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> > >> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> > >> functions).
> > >>
> > >> As found with Coccinelle[1], add __counted_by for struct smu10_voltage_dependency_table.
> > >>
> > >> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> > >>
> > >> Cc: Evan Quan <evan.quan@xxxxxxx>
> > >> Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> > >> Cc: "Christian König" <christian.koenig@xxxxxxx>
> > >> Cc: "Pan, Xinhui" <Xinhui.Pan@xxxxxxx>
> > >> Cc: David Airlie <airlied@xxxxxxxxx>
> > >> Cc: Daniel Vetter <daniel@xxxxxxxx>
> > >> Cc: Xiaojian Du <Xiaojian.Du@xxxxxxx>
> > >> Cc: Huang Rui <ray.huang@xxxxxxx>
> > >> Cc: Kevin Wang <kevin1.wang@xxxxxxx>
> > >> Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
> > >> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> > >> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> > > Acked-by: Alex Deucher <alexander.deucher@xxxxxxx>
> >
> > Mhm, I'm not sure if this is a good idea. That is a structure filled in
> > by the firmware, isn't it?
> >
> > That would imply that we might need to byte swap count before it is
> > checkable.
>
> True. Good point.  Same for the other amdgpu patch.

Actually the other patch is fine.  That's just a local structure.

Alex

>
> Alex
>
> >
> > Regards,
> > Christian.
> >
> > >
> > >> ---
> > >>   drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu10_hwmgr.h | 2 +-
> > >>   1 file changed, 1 insertion(+), 1 deletion(-)
> > >>
> > >> diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu10_hwmgr.h b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu10_hwmgr.h
> > >> index 808e0ecbe1f0..42adc2a3dcbc 100644
> > >> --- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu10_hwmgr.h
> > >> +++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu10_hwmgr.h
> > >> @@ -192,7 +192,7 @@ struct smu10_clock_voltage_dependency_record {
> > >>
> > >>   struct smu10_voltage_dependency_table {
> > >>          uint32_t count;
> > >> -       struct smu10_clock_voltage_dependency_record entries[];
> > >> +       struct smu10_clock_voltage_dependency_record entries[] __counted_by(count);
> > >>   };
> > >>
> > >>   struct smu10_clock_voltage_information {
> > >> --
> > >> 2.34.1
> > >>
> >