2022-07-02 16:10:06

by Tom Rix

Subject: [PATCH] drm/nouveau/bios: set info only when the return is not 0

clang static analysis reports
drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c:68:17: warning: The right operand of '*' is a garbage value [core.UndefinedBinaryOperatorResult]
switch (!!data * *ver) {
^ ~~~~
A switch statement with only a default should be reduced to an if.

If nvbios_pmuEp() returns 0, via the data variable, the output info parameter
is not used. So set info only when data is not 0.

The struct nvbios_pmuE only has the type and data elements. Since both of these
are explicitly set, memset is not needed. So remove it.

Signed-off-by: Tom Rix <[email protected]>
---
drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c
index b4a308f3cf7b..49e2664a734c 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c
@@ -64,12 +64,9 @@ nvbios_pmuEp(struct nvkm_bios *bios, int idx, u8 *ver, u8 *hdr,
struct nvbios_pmuE *info)
{
u32 data = nvbios_pmuEe(bios, idx, ver, hdr);
- memset(info, 0x00, sizeof(*info));
- switch (!!data * *ver) {
- default:
+ if (data) {
info->type = nvbios_rd08(bios, data + 0x00);
info->data = nvbios_rd32(bios, data + 0x02);
- break;
}
return data;
}
--
2.27.0

2022-07-04 21:52:34

by Lyude Paul

Subject: Re: [PATCH] drm/nouveau/bios: set info only when the return is not 0

Reviewed-by: Lyude Paul <[email protected]>

Currently on flakey internet in the back of a car, so I probably won't be able
to push this until I get back tonight or early tomorrow

On Sat, 2022-07-02 at 11:39 -0400, Tom Rix wrote:
> clang static analysis reports
> drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c:68:17: warning: The right
> operand of '*' is a garbage value [core.UndefinedBinaryOperatorResult]
>         switch (!!data * *ver) {
>                        ^ ~~~~
> A switch statement with only a default should be reduced to an if.
>
> If nvbios_pmuEp() returns 0, via the data variable, the output info
> parameter
> is not used.  So set info only when data is not 0.
>
> The struct nvbios_pmuE only has the type and data elements.  Since both of
> these
> are explicitly set, memset is not needed.  So remove it.
>
> Signed-off-by: Tom Rix <[email protected]>
> ---
>  drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c
> b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c
> index b4a308f3cf7b..49e2664a734c 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c
> @@ -64,12 +64,9 @@ nvbios_pmuEp(struct nvkm_bios *bios, int idx, u8 *ver, u8
> *hdr,
>              struct nvbios_pmuE *info)
>  {
>         u32 data = nvbios_pmuEe(bios, idx, ver, hdr);
> -       memset(info, 0x00, sizeof(*info));
> -       switch (!!data * *ver) {
> -       default:
> +       if (data) {
>                 info->type = nvbios_rd08(bios, data + 0x00);
>                 info->data = nvbios_rd32(bios, data + 0x02);
> -               break;
>         }
>         return data;
>  }

--
Cheers,
Lyude Paul (she/her)
Software Engineer at Red Hat

2022-07-15 19:14:50

by Lyude Paul

Subject: Re: [PATCH] drm/nouveau/bios: set info only when the return is not 0

On Mon, 2022-07-04 at 17:32 -0400, Lyude Paul wrote:
> Reviewed-by: Lyude Paul <[email protected]>
>
> Currently on flakey internet in the back of a car, so I probably won't be
> able
> to push this until I get back tonight or early tomorrow

Whoops! Slipped my mind when I got back, but I just remembered it now so I
will go ahead and push :). apologies for the delay!

>
> On Sat, 2022-07-02 at 11:39 -0400, Tom Rix wrote:
> > clang static analysis reports
> > drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c:68:17: warning: The right
> > operand of '*' is a garbage value [core.UndefinedBinaryOperatorResult]
> >         switch (!!data * *ver) {
> >                        ^ ~~~~
> > A switch statement with only a default should be reduced to an if.
> >
> > If nvbios_pmuEp() returns 0, via the data variable, the output info
> > parameter
> > is not used.  So set info only when data is not 0.
> >
> > The struct nvbios_pmuE only has the type and data elements.  Since both of
> > these
> > are explicitly set, memset is not needed.  So remove it.
> >
> > Signed-off-by: Tom Rix <[email protected]>
> > ---
> >  drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c | 5 +----
> >  1 file changed, 1 insertion(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c
> > b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c
> > index b4a308f3cf7b..49e2664a734c 100644
> > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c
> > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c
> > @@ -64,12 +64,9 @@ nvbios_pmuEp(struct nvkm_bios *bios, int idx, u8 *ver,
> > u8
> > *hdr,
> >              struct nvbios_pmuE *info)
> >  {
> >         u32 data = nvbios_pmuEe(bios, idx, ver, hdr);
> > -       memset(info, 0x00, sizeof(*info));
> > -       switch (!!data * *ver) {
> > -       default:
> > +       if (data) {
> >                 info->type = nvbios_rd08(bios, data + 0x00);
> >                 info->data = nvbios_rd32(bios, data + 0x02);
> > -               break;
> >         }
> >         return data;
> >  }
>

--
Cheers,
Lyude Paul (she/her)
Software Engineer at Red Hat

2022-07-15 20:33:23

by Tom Rix

Subject: Re: [PATCH] drm/nouveau/bios: set info only when the return is not 0

On 7/15/22 12:09 PM, Lyude Paul wrote:
> On Mon, 2022-07-04 at 17:32 -0400, Lyude Paul wrote:
>> Reviewed-by: Lyude Paul <[email protected]>
>>
>> Currently on flakey internet in the back of a car, so I probably won't be
>> able
>> to push this until I get back tonight or early tomorrow
> Whoops! Slipped my mind when I got back, but I just remembered it now so I
> will go ahead and push :). apologies for the delay!

Thanks!

T

>
>> On Sat, 2022-07-02 at 11:39 -0400, Tom Rix wrote:
>>> clang static analysis reports
>>> drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c:68:17: warning: The right
>>> operand of '*' is a garbage value [core.UndefinedBinaryOperatorResult]
>>>         switch (!!data * *ver) {
>>>                        ^ ~~~~
>>> A switch statement with only a default should be reduced to an if.
>>>
>>> If nvbios_pmuEp() returns 0, via the data variable, the output info
>>> parameter
>>> is not used.  So set info only when data is not 0.
>>>
>>> The struct nvbios_pmuE only has the type and data elements.  Since both of
>>> these
>>> are explicitly set, memset is not needed.  So remove it.
>>>
>>> Signed-off-by: Tom Rix <[email protected]>
>>> ---
>>>  drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c | 5 +----
>>>  1 file changed, 1 insertion(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c
>>> b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c
>>> index b4a308f3cf7b..49e2664a734c 100644
>>> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c
>>> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c
>>> @@ -64,12 +64,9 @@ nvbios_pmuEp(struct nvkm_bios *bios, int idx, u8 *ver,
>>> u8
>>> *hdr,
>>>              struct nvbios_pmuE *info)
>>>  {
>>>         u32 data = nvbios_pmuEe(bios, idx, ver, hdr);
>>> -       memset(info, 0x00, sizeof(*info));
>>> -       switch (!!data * *ver) {
>>> -       default:
>>> +       if (data) {
>>>                 info->type = nvbios_rd08(bios, data + 0x00);
>>>                 info->data = nvbios_rd32(bios, data + 0x02);
>>> -               break;
>>>         }
>>>         return data;
>>>  }