2023-02-17 12:47:37

by Arnd Bergmann

Subject: [PATCH] drm/i915/guc: avoid FIELD_PREP warning

From: Arnd Bergmann <[email protected]>

With gcc-7 and earlier, there are lots of warnings like

In file included from <command-line>:0:0:
In function '__guc_context_policy_add_priority.isra.66',
inlined from '__guc_context_set_prio.isra.67' at drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:3292:3,
inlined from 'guc_context_set_prio' at drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:3320:2:
include/linux/compiler_types.h:399:38: error: call to '__compiletime_assert_631' declared with attribute error: FIELD_PREP: mask is not constant
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^
...
drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:2422:3: note: in expansion of macro 'FIELD_PREP'
FIELD_PREP(GUC_KLV_0_KEY, GUC_CONTEXT_POLICIES_KLV_ID_##id) | \
^~~~~~~~~~

Make sure that GUC_KLV_0_KEY is an unsigned value to avoid the warning.

Fixes: 77b6f79df66e ("drm/i915/guc: Update to GuC version 69.0.3")
Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h b/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
index 58012edd4eb0..4f4f53c42a9c 100644
--- a/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
+++ b/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
@@ -29,9 +29,9 @@
*/

#define GUC_KLV_LEN_MIN 1u
-#define GUC_KLV_0_KEY (0xffff << 16)
-#define GUC_KLV_0_LEN (0xffff << 0)
-#define GUC_KLV_n_VALUE (0xffffffff << 0)
+#define GUC_KLV_0_KEY (0xffffu << 16)
+#define GUC_KLV_0_LEN (0xffffu << 0)
+#define GUC_KLV_n_VALUE (0xffffffffu << 0)

/**
* DOC: GuC Self Config KLVs
--
2.39.1

2023-02-17 15:38:18

by Andrzej Hajda

Subject: Re: [Intel-gfx] [PATCH] drm/i915/guc: avoid FIELD_PREP warning

On 17.02.2023 13:46, Arnd Bergmann wrote:
> From: Arnd Bergmann <[email protected]>
>
> With gcc-7 and earlier, there are lots of warnings like
>
> In file included from <command-line>:0:0:
> In function '__guc_context_policy_add_priority.isra.66',
> inlined from '__guc_context_set_prio.isra.67' at drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:3292:3,
> inlined from 'guc_context_set_prio' at drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:3320:2:
> include/linux/compiler_types.h:399:38: error: call to '__compiletime_assert_631' declared with attribute error: FIELD_PREP: mask is not constant
> _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> ^
> ...
> drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:2422:3: note: in expansion of macro 'FIELD_PREP'
> FIELD_PREP(GUC_KLV_0_KEY, GUC_CONTEXT_POLICIES_KLV_ID_##id) | \
> ^~~~~~~~~~
>
> Make sure that GUC_KLV_0_KEY is an unsigned value to avoid the warning.

Does it mean __builtin_constant_p in gcc7 returns 0 on signed constants?
I guess there should be more similar errors.

Regards
Andrzej


>
> Fixes: 77b6f79df66e ("drm/i915/guc: Update to GuC version 69.0.3")
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h b/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
> index 58012edd4eb0..4f4f53c42a9c 100644
> --- a/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
> +++ b/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
> @@ -29,9 +29,9 @@
> */
>
> #define GUC_KLV_LEN_MIN 1u
> -#define GUC_KLV_0_KEY (0xffff << 16)
> -#define GUC_KLV_0_LEN (0xffff << 0)
> -#define GUC_KLV_n_VALUE (0xffffffff << 0)
> +#define GUC_KLV_0_KEY (0xffffu << 16)
> +#define GUC_KLV_0_LEN (0xffffu << 0)
> +#define GUC_KLV_n_VALUE (0xffffffffu << 0)
>
> /**
> * DOC: GuC Self Config KLVs

2023-02-17 16:07:34

by Rodrigo Vivi

Subject: Re: [PATCH] drm/i915/guc: avoid FIELD_PREP warning

On Fri, Feb 17, 2023 at 01:46:50PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <[email protected]>
>
> With gcc-7 and earlier, there are lots of warnings like
>
> In file included from <command-line>:0:0:
> In function '__guc_context_policy_add_priority.isra.66',
> inlined from '__guc_context_set_prio.isra.67' at drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:3292:3,
> inlined from 'guc_context_set_prio' at drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:3320:2:
> include/linux/compiler_types.h:399:38: error: call to '__compiletime_assert_631' declared with attribute error: FIELD_PREP: mask is not constant
> _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> ^
> ...
> drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:2422:3: note: in expansion of macro 'FIELD_PREP'
> FIELD_PREP(GUC_KLV_0_KEY, GUC_CONTEXT_POLICIES_KLV_ID_##id) | \
> ^~~~~~~~~~
>
> Make sure that GUC_KLV_0_KEY is an unsigned value to avoid the warning.
>
> Fixes: 77b6f79df66e ("drm/i915/guc: Update to GuC version 69.0.3")
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h b/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
> index 58012edd4eb0..4f4f53c42a9c 100644
> --- a/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
> +++ b/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
> @@ -29,9 +29,9 @@
> */
>
> #define GUC_KLV_LEN_MIN 1u
> -#define GUC_KLV_0_KEY (0xffff << 16)
> -#define GUC_KLV_0_LEN (0xffff << 0)
> -#define GUC_KLV_n_VALUE (0xffffffff << 0)
> +#define GUC_KLV_0_KEY (0xffffu << 16)
> +#define GUC_KLV_0_LEN (0xffffu << 0)
> +#define GUC_KLV_n_VALUE (0xffffffffu << 0)

what about changing them to GENMASK?

>
> /**
> * DOC: GuC Self Config KLVs
> --
> 2.39.1
>

2023-02-17 16:17:20

by Arnd Bergmann

Subject: Re: [Intel-gfx] [PATCH] drm/i915/guc: avoid FIELD_PREP warning

On Fri, Feb 17, 2023, at 16:38, Andrzej Hajda wrote:
> On 17.02.2023 13:46, Arnd Bergmann wrote:
>> From: Arnd Bergmann <[email protected]>
>>
>> With gcc-7 and earlier, there are lots of warnings like
>>
>> In file included from <command-line>:0:0:
>> In function '__guc_context_policy_add_priority.isra.66',
>> inlined from '__guc_context_set_prio.isra.67' at drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:3292:3,
>> inlined from 'guc_context_set_prio' at drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:3320:2:
>> include/linux/compiler_types.h:399:38: error: call to '__compiletime_assert_631' declared with attribute error: FIELD_PREP: mask is not constant
>> _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>> ^
>> ...
>> drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:2422:3: note: in expansion of macro 'FIELD_PREP'
>> FIELD_PREP(GUC_KLV_0_KEY, GUC_CONTEXT_POLICIES_KLV_ID_##id) | \
>> ^~~~~~~~~~
>>
>> Make sure that GUC_KLV_0_KEY is an unsigned value to avoid the warning.
>
> Does it mean __builtin_constant_p in gcc7 returns 0 on signed constants?
> I guess there should be more similar errors.

No, it's not as simple as that, I'm not really sure what the underlying
problem is with the compiler, and this is the only file that triggered
this particular warning.

There are other cases where old compilers had the reverse problem,
where they sometimes report a variable to be __builtin_constant_p()==true
if there is a branch that assigns a constant to it.

I think here it happens because GUC_KLV_0_KEY and GUC_KLV_n_VALUE are
negative.

Arnd

2023-02-20 12:52:27

by Michal Wajdeczko

Subject: Re: [PATCH] drm/i915/guc: avoid FIELD_PREP warning

On 17.02.2023 13:46, Arnd Bergmann wrote:
> From: Arnd Bergmann <[email protected]>
>
> With gcc-7 and earlier, there are lots of warnings like
>
> In file included from <command-line>:0:0:
> In function '__guc_context_policy_add_priority.isra.66',
> inlined from '__guc_context_set_prio.isra.67' at drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:3292:3,
> inlined from 'guc_context_set_prio' at drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:3320:2:
> include/linux/compiler_types.h:399:38: error: call to '__compiletime_assert_631' declared with attribute error: FIELD_PREP: mask is not constant
> _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> ^
> ...
> drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:2422:3: note: in expansion of macro 'FIELD_PREP'
> FIELD_PREP(GUC_KLV_0_KEY, GUC_CONTEXT_POLICIES_KLV_ID_##id) | \
> ^~~~~~~~~~
>
> Make sure that GUC_KLV_0_KEY is an unsigned value to avoid the warning.
>
> Fixes: 77b6f79df66e ("drm/i915/guc: Update to GuC version 69.0.3")
> Signed-off-by: Arnd Bergmann <[email protected]>

Reviewed-by: Michal Wajdeczko <[email protected]>

> ---
> drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h b/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
> index 58012edd4eb0..4f4f53c42a9c 100644
> --- a/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
> +++ b/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
> @@ -29,9 +29,9 @@
> */
>
> #define GUC_KLV_LEN_MIN 1u
> -#define GUC_KLV_0_KEY (0xffff << 16)
> -#define GUC_KLV_0_LEN (0xffff << 0)
> -#define GUC_KLV_n_VALUE (0xffffffff << 0)
> +#define GUC_KLV_0_KEY (0xffffu << 16)
> +#define GUC_KLV_0_LEN (0xffffu << 0)
> +#define GUC_KLV_n_VALUE (0xffffffffu << 0)
>
> /**
> * DOC: GuC Self Config KLVs