* [PATCH] drm/i915/gt: fix unsigned integer to signed assignment
@ 2022-02-16 8:38 Jiapeng Chong
2022-02-16 9:02 ` Jani Nikula
0 siblings, 1 reply; 5+ messages in thread
From: Jiapeng Chong @ 2022-02-16 8:38 UTC (permalink / raw)
To: jani.nikula
Cc: joonas.lahtinen, rodrigo.vivi, tvrtko.ursulin, airlied, daniel,
sumit.semwal, christian.koenig, intel-gfx, dri-devel,
linux-kernel, linux-media, linaro-mm-sig, Jiapeng Chong,
Abaci Robot
Eliminate the follow smatch warning:
drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:4640
guc_create_virtual() warn: assigning (-2) to unsigned variable
've->base.instance'.
drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:4641
guc_create_virtual() warn: assigning (-2) to unsigned variable
've->base.uabi_instance'.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
---
drivers/gpu/drm/i915/gt/intel_engine_types.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index 36365bdbe1ee..dc7cc06c68e7 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -328,10 +328,10 @@ struct intel_engine_cs {
intel_engine_mask_t logical_mask;
u8 class;
- u8 instance;
+ s8 instance;
u16 uabi_class;
- u16 uabi_instance;
+ s16 uabi_instance;
u32 uabi_capabilities;
u32 context_size;
--
2.20.1.7.g153144c
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] drm/i915/gt: fix unsigned integer to signed assignment
2022-02-16 8:38 [PATCH] drm/i915/gt: fix unsigned integer to signed assignment Jiapeng Chong
@ 2022-02-16 9:02 ` Jani Nikula
2022-02-16 9:19 ` Ville Syrjälä
0 siblings, 1 reply; 5+ messages in thread
From: Jani Nikula @ 2022-02-16 9:02 UTC (permalink / raw)
To: Jiapeng Chong
Cc: joonas.lahtinen, rodrigo.vivi, tvrtko.ursulin, airlied, daniel,
sumit.semwal, christian.koenig, intel-gfx, dri-devel,
linux-kernel, linux-media, linaro-mm-sig, Jiapeng Chong,
Abaci Robot
On Wed, 16 Feb 2022, Jiapeng Chong <jiapeng.chong@linux.alibaba.com> wrote:
> Eliminate the follow smatch warning:
>
> drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:4640
> guc_create_virtual() warn: assigning (-2) to unsigned variable
> 've->base.instance'.
>
> drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:4641
> guc_create_virtual() warn: assigning (-2) to unsigned variable
> 've->base.uabi_instance'.
>
> Reported-by: Abaci Robot <abaci@linux.alibaba.com>
> Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
The report seems to be valid, but I don't think this is the fix.
Where do we even check for invalid instance/uabi_instance in code?
BR,
Jani.
> ---
> drivers/gpu/drm/i915/gt/intel_engine_types.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> index 36365bdbe1ee..dc7cc06c68e7 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> @@ -328,10 +328,10 @@ struct intel_engine_cs {
> intel_engine_mask_t logical_mask;
>
> u8 class;
> - u8 instance;
> + s8 instance;
>
> u16 uabi_class;
> - u16 uabi_instance;
> + s16 uabi_instance;
>
> u32 uabi_capabilities;
> u32 context_size;
--
Jani Nikula, Intel Open Source Graphics Center
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] drm/i915/gt: fix unsigned integer to signed assignment
2022-02-16 9:02 ` Jani Nikula
@ 2022-02-16 9:19 ` Ville Syrjälä
2022-02-16 9:57 ` Tvrtko Ursulin
0 siblings, 1 reply; 5+ messages in thread
From: Ville Syrjälä @ 2022-02-16 9:19 UTC (permalink / raw)
To: Jani Nikula
Cc: Jiapeng Chong, tvrtko.ursulin, airlied, intel-gfx, Abaci Robot,
linux-kernel, dri-devel, christian.koenig, linaro-mm-sig,
rodrigo.vivi, sumit.semwal, linux-media
On Wed, Feb 16, 2022 at 11:02:06AM +0200, Jani Nikula wrote:
> On Wed, 16 Feb 2022, Jiapeng Chong <jiapeng.chong@linux.alibaba.com> wrote:
> > Eliminate the follow smatch warning:
> >
> > drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:4640
> > guc_create_virtual() warn: assigning (-2) to unsigned variable
> > 've->base.instance'.
> >
> > drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:4641
> > guc_create_virtual() warn: assigning (-2) to unsigned variable
> > 've->base.uabi_instance'.
> >
> > Reported-by: Abaci Robot <abaci@linux.alibaba.com>
> > Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
>
> The report seems to be valid, but I don't think this is the fix.
>
> Where do we even check for invalid instance/uabi_instance in code?
The whole thing seems rather poorly documented as there's a matching
uabi struct with __u16's and the negative values are defined right
there in the uapi header as well.
>
> BR,
> Jani.
>
>
> > ---
> > drivers/gpu/drm/i915/gt/intel_engine_types.h | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> > index 36365bdbe1ee..dc7cc06c68e7 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
> > +++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> > @@ -328,10 +328,10 @@ struct intel_engine_cs {
> > intel_engine_mask_t logical_mask;
> >
> > u8 class;
> > - u8 instance;
> > + s8 instance;
> >
> > u16 uabi_class;
> > - u16 uabi_instance;
> > + s16 uabi_instance;
> >
> > u32 uabi_capabilities;
> > u32 context_size;
>
> --
> Jani Nikula, Intel Open Source Graphics Center
--
Ville Syrjälä
Intel
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] drm/i915/gt: fix unsigned integer to signed assignment
2022-02-16 9:19 ` Ville Syrjälä
@ 2022-02-16 9:57 ` Tvrtko Ursulin
2022-02-16 10:33 ` Jani Nikula
0 siblings, 1 reply; 5+ messages in thread
From: Tvrtko Ursulin @ 2022-02-16 9:57 UTC (permalink / raw)
To: Ville Syrjälä, Jani Nikula
Cc: Jiapeng Chong, airlied, intel-gfx, Abaci Robot, linux-kernel,
dri-devel, christian.koenig, linaro-mm-sig, rodrigo.vivi,
sumit.semwal, linux-media
On 16/02/2022 09:19, Ville Syrjälä wrote:
> On Wed, Feb 16, 2022 at 11:02:06AM +0200, Jani Nikula wrote:
>> On Wed, 16 Feb 2022, Jiapeng Chong <jiapeng.chong@linux.alibaba.com> wrote:
>>> Eliminate the follow smatch warning:
>>>
>>> drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:4640
>>> guc_create_virtual() warn: assigning (-2) to unsigned variable
>>> 've->base.instance'.
>>>
>>> drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:4641
>>> guc_create_virtual() warn: assigning (-2) to unsigned variable
>>> 've->base.uabi_instance'.
>>>
>>> Reported-by: Abaci Robot <abaci@linux.alibaba.com>
>>> Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
>>
>> The report seems to be valid, but I don't think this is the fix.
>>
>> Where do we even check for invalid instance/uabi_instance in code?
>
> The whole thing seems rather poorly documented as there's a matching
> uabi struct with __u16's and the negative values are defined right
> there in the uapi header as well.
Negative ones are exception values to be used in conjunction with the virtual engine uapi (see "DOC: Virtual Engine uAPI" and also comment next to I915_CONTEXT_PARAM_ENGINES).
AFAIK assigning negative int to unsigned int is defined and fine.
Compiler does warn on comparisons which is why we have:
./gem/i915_gem_busy.c: if (id == (u16)I915_ENGINE_CLASS_INVALID)
./gem/i915_gem_busy.c: if (id == (u16)I915_ENGINE_CLASS_INVALID)
./gem/i915_gem_context.c: if (ci.engine_class == (u16)I915_ENGINE_CLASS_INVALID &&
./gem/i915_gem_context.c: ci.engine_instance == (u16)I915_ENGINE_CLASS_INVALID_NONE)
So I think no action needed here.
Regards,
Tvrtko
>>
>> BR,
>> Jani.
>>
>>
>>> ---
>>> drivers/gpu/drm/i915/gt/intel_engine_types.h | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
>>> index 36365bdbe1ee..dc7cc06c68e7 100644
>>> --- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
>>> +++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
>>> @@ -328,10 +328,10 @@ struct intel_engine_cs {
>>> intel_engine_mask_t logical_mask;
>>>
>>> u8 class;
>>> - u8 instance;
>>> + s8 instance;
>>>
>>> u16 uabi_class;
>>> - u16 uabi_instance;
>>> + s16 uabi_instance;
>>>
>>> u32 uabi_capabilities;
>>> u32 context_size;
>>
>> --
>> Jani Nikula, Intel Open Source Graphics Center
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] drm/i915/gt: fix unsigned integer to signed assignment
2022-02-16 9:57 ` Tvrtko Ursulin
@ 2022-02-16 10:33 ` Jani Nikula
0 siblings, 0 replies; 5+ messages in thread
From: Jani Nikula @ 2022-02-16 10:33 UTC (permalink / raw)
To: Tvrtko Ursulin, Ville Syrjälä
Cc: Jiapeng Chong, airlied, intel-gfx, Abaci Robot, linux-kernel,
dri-devel, christian.koenig, linaro-mm-sig, rodrigo.vivi,
sumit.semwal, linux-media
On Wed, 16 Feb 2022, Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> wrote:
> On 16/02/2022 09:19, Ville Syrjälä wrote:
>> On Wed, Feb 16, 2022 at 11:02:06AM +0200, Jani Nikula wrote:
>>> On Wed, 16 Feb 2022, Jiapeng Chong <jiapeng.chong@linux.alibaba.com> wrote:
>>>> Eliminate the follow smatch warning:
>>>>
>>>> drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:4640
>>>> guc_create_virtual() warn: assigning (-2) to unsigned variable
>>>> 've->base.instance'.
>>>>
>>>> drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:4641
>>>> guc_create_virtual() warn: assigning (-2) to unsigned variable
>>>> 've->base.uabi_instance'.
>>>>
>>>> Reported-by: Abaci Robot <abaci@linux.alibaba.com>
>>>> Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
>>>
>>> The report seems to be valid, but I don't think this is the fix.
>>>
>>> Where do we even check for invalid instance/uabi_instance in code?
>>
>> The whole thing seems rather poorly documented as there's a matching
>> uabi struct with __u16's and the negative values are defined right
>> there in the uapi header as well.
>
> Negative ones are exception values to be used in conjunction with the virtual engine uapi (see "DOC: Virtual Engine uAPI" and also comment next to I915_CONTEXT_PARAM_ENGINES).
>
> AFAIK assigning negative int to unsigned int is defined and fine.
>
> Compiler does warn on comparisons which is why we have:
>
> ./gem/i915_gem_busy.c: if (id == (u16)I915_ENGINE_CLASS_INVALID)
> ./gem/i915_gem_busy.c: if (id == (u16)I915_ENGINE_CLASS_INVALID)
> ./gem/i915_gem_context.c: if (ci.engine_class == (u16)I915_ENGINE_CLASS_INVALID &&
> ./gem/i915_gem_context.c: ci.engine_instance == (u16)I915_ENGINE_CLASS_INVALID_NONE)
>
> So I think no action needed here.
We never check instance or uabi_instance members against
I915_ENGINE_CLASS_INVALID_VIRTUAL anywhere.
BR,
Jani.
>
> Regards,
>
> Tvrtko
>
>>>
>>> BR,
>>> Jani.
>>>
>>>
>>>> ---
>>>> drivers/gpu/drm/i915/gt/intel_engine_types.h | 4 ++--
>>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
>>>> index 36365bdbe1ee..dc7cc06c68e7 100644
>>>> --- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
>>>> +++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
>>>> @@ -328,10 +328,10 @@ struct intel_engine_cs {
>>>> intel_engine_mask_t logical_mask;
>>>>
>>>> u8 class;
>>>> - u8 instance;
>>>> + s8 instance;
>>>>
>>>> u16 uabi_class;
>>>> - u16 uabi_instance;
>>>> + s16 uabi_instance;
>>>>
>>>> u32 uabi_capabilities;
>>>> u32 context_size;
>>>
>>> --
>>> Jani Nikula, Intel Open Source Graphics Center
>>
--
Jani Nikula, Intel Open Source Graphics Center
^ permalink raw reply [flat|nested] 5+ messages in thread
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2022-02-16 8:38 [PATCH] drm/i915/gt: fix unsigned integer to signed assignment Jiapeng Chong
2022-02-16 9:02 ` Jani Nikula
2022-02-16 9:19 ` Ville Syrjälä
2022-02-16 9:57 ` Tvrtko Ursulin
2022-02-16 10:33 ` Jani Nikula
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