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

[Alex Deucher]

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.

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
> >>
>