diff mbox series

drm/i915/guc: avoid FIELD_PREP warning

Message ID	20230217124724.1324126-1-arnd@kernel.org
State	New
Headers	Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; From: Arnd Bergmann <arnd@kernel.org> To: Jani Nikula <jani.nikula@linux.intel.com>, Joonas Lahtinen <joonas.lahtinen@linux.intel.com>, Rodrigo Vivi <rodrigo.vivi@intel.com>, Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>, David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>, Matthew Brost <matthew.brost@intel.com>, John Harrison <John.C.Harrison@Intel.com>, Michal Wajdeczko <michal.wajdeczko@intel.com> Cc: Arnd Bergmann <arnd@arndb.de>, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH] drm/i915/guc: avoid FIELD_PREP warning Date: Fri, 17 Feb 2023 13:46:50 +0100 Message-Id: <20230217124724.1324126-1-arnd@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	drm/i915/guc: avoid FIELD_PREP warning \| drm/i915/guc: avoid FIELD_PREP warning

Commit Message

Arnd Bergmann Feb. 17, 2023, 12:46 p.m. UTC

  From: Arnd Bergmann <arnd@arndb.de>

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 <arnd@arndb.de>
---
 drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Andrzej Hajda Feb. 17, 2023, 3:38 p.m. UTC | #1

On 17.02.2023 13:46, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> 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 <arnd@arndb.de>
> ---
>   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

Rodrigo Vivi Feb. 17, 2023, 4:07 p.m. UTC | #2

On Fri, Feb 17, 2023 at 01:46:50PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> 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 <arnd@arndb.de>
> ---
>  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
>

Arnd Bergmann Feb. 17, 2023, 4:15 p.m. UTC | #3

On Fri, Feb 17, 2023, at 16:38, Andrzej Hajda wrote:
> On 17.02.2023 13:46, Arnd Bergmann wrote:
>> From: Arnd Bergmann <arnd@arndb.de>
>> 
>> 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

Michal Wajdeczko Feb. 20, 2023, 12:51 p.m. UTC | #4

On 17.02.2023 13:46, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> 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 <arnd@arndb.de>

Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>

> ---
>  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

diff mbox series

Patch

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