[PATCH v2] coresight: etm4x: Fix width of CCITMIN field

[PATCH v2] coresight: etm4x: Fix width of CCITMIN field

[James Clark]

CCITMIN is a 12 bit field and doesn't fit in a u8, so extend it to u16.
This probably wasn't an issue previously because values higher than 255
never occurred.

But since commit 0f55b43dedcd ("coresight: etm: Override TRCIDR3.CCITMIN
on errata affected cpus"), a comparison with 256 was done to enable the
errata, generating the following W=1 build error:

  coresight-etm4x-core.c:1188:24: error: result of comparison of
  constant 256 with expression of type 'u8' (aka 'unsigned char') is
  always false [-Werror,-Wtautological-constant-out-of-range-compare]

   if (drvdata->ccitmin == 256)

Cc: stable@vger.kernel.org
Fixes: 2e1cdfe184b5 ("coresight-etm4x: Adding CoreSight ETM4x driver")
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@arm.com>
---

Changes since V1:
  * Change the fixes commit to the original addition of ccitmin, rather
    than the last refactor of the struct.

 drivers/hwtracing/coresight/coresight-etm4x.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
index 20e2e4cb7614..da17b6c49b0f 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.h
+++ b/drivers/hwtracing/coresight/coresight-etm4x.h
@@ -1036,7 +1036,7 @@ struct etmv4_drvdata {
 	u8				ctxid_size;
 	u8				vmid_size;
 	u8				ccsize;
-	u8				ccitmin;
+	u16				ccitmin;
 	u8				s_ex_level;
 	u8				ns_ex_level;
 	u8				q_support;
-- 
2.34.1

Re: [PATCH v2] coresight: etm4x: Fix width of CCITMIN field

[Suzuki K Poulose]

On 01/11/2023 11:52, James Clark wrote:
> CCITMIN is a 12 bit field and doesn't fit in a u8, so extend it to u16.
> This probably wasn't an issue previously because values higher than 255
> never occurred.
> 
> But since commit 0f55b43dedcd ("coresight: etm: Override TRCIDR3.CCITMIN
> on errata affected cpus"), a comparison with 256 was done to enable the
> errata, generating the following W=1 build error:
> 
>    coresight-etm4x-core.c:1188:24: error: result of comparison of
>    constant 256 with expression of type 'u8' (aka 'unsigned char') is
>    always false [-Werror,-Wtautological-constant-out-of-range-compare]
> 
>     if (drvdata->ccitmin == 256)
> 
> Cc: stable@vger.kernel.org
> Fixes: 2e1cdfe184b5 ("coresight-etm4x: Adding CoreSight ETM4x driver")
> Reviewed-by: Mike Leach <mike.leach@linaro.org>
> Signed-off-by: James Clark <james.clark@arm.com>

Thanks, applied to coresight next :


Suzuki