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SubjectRe: [PATCH v4 1/2] perf/smmuv3: Don't reserve the PMCG register spaces
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On 2021/2/1 20:54, Will Deacon wrote:
> On Sat, Jan 30, 2021 at 03:14:13PM +0800, Zhen Lei wrote:
>> According to the SMMUv3 specification:
>> Each PMCG counter group is represented by one 4KB page (Page 0) with one
>> optional additional 4KB page (Page 1), both of which are at IMPLEMENTATION
>> DEFINED base addresses.
>>
>> This means that the PMCG register spaces may be within the 64KB pages of
>> the SMMUv3 register space. When both the SMMU and PMCG drivers reserve
>> their own resources, a resource conflict occurs.
>>
>> To avoid this conflict, don't reserve the PMCG regions.
>>
>> Suggested-by: Robin Murphy <robin.murphy@arm.com>
>> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
>> ---
>> drivers/perf/arm_smmuv3_pmu.c | 25 +++++++++++++++++++------
>> 1 file changed, 19 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/perf/arm_smmuv3_pmu.c b/drivers/perf/arm_smmuv3_pmu.c
>> index 74474bb322c3f26..5e894f957c7b935 100644
>> --- a/drivers/perf/arm_smmuv3_pmu.c
>> +++ b/drivers/perf/arm_smmuv3_pmu.c
>> @@ -793,17 +793,30 @@ static int smmu_pmu_probe(struct platform_device *pdev)
>> .capabilities = PERF_PMU_CAP_NO_EXCLUDE,
>> };
>>
>> - smmu_pmu->reg_base = devm_platform_get_and_ioremap_resource(pdev, 0, &res_0);
>> - if (IS_ERR(smmu_pmu->reg_base))
>> - return PTR_ERR(smmu_pmu->reg_base);
>> + /*
>> + * The register spaces of the PMCG may be in the register space of
>> + * other devices. For example, SMMU. Therefore, the PMCG resources are
>> + * not reserved to avoid resource conflicts with other drivers.
>> + */
>> + res_0 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + if (!res_0)
>> + return ERR_PTR(-EINVAL);
>
> I tried to apply this, but you've got your return type in a muddle:

I'm dizzy. I don't know how this bug patch came out. I just pinched my leg, like I'm still in the real world.

The "ERR_PTR()" of the four ERR_PTR(xxx) should be removed. Can you help me? Or I send a new one.

>
> @@ @@
> +drivers/perf/arm_smmuv3_pmu.c: In function ‘smmu_pmu_probe’:
> +drivers/perf/arm_smmuv3_pmu.c:803:10: warning: returning ‘void *’ from a function with return type ‘int’ makes integer from pointer without a cast [-Wint-conversion]
> + 803 | return ERR_PTR(-EINVAL);
> + | ^~~~~~~~~~~~~~~~
> +drivers/perf/arm_smmuv3_pmu.c:803:31: warning: incorrect type in return expression (different base types) [sparse]
> +drivers/perf/arm_smmuv3_pmu.c:803:31: expected int [sparse]
> +drivers/perf/arm_smmuv3_pmu.c:803:31: got void * [sparse]
> +drivers/perf/arm_smmuv3_pmu.c:806:10: warning: returning ‘void *’ from a function with return type ‘int’ makes integer from pointer without a cast [-Wint-conversion]
> + 806 | return ERR_PTR(-ENOMEM);
> + | ^~~~~~~~~~~~~~~~
> +drivers/perf/arm_smmuv3_pmu.c:806:31: warning: incorrect type in return expression (different base types) [sparse]
> +drivers/perf/arm_smmuv3_pmu.c:806:31: expected int [sparse]
> +drivers/perf/arm_smmuv3_pmu.c:806:31: got void * [sparse]
> +drivers/perf/arm_smmuv3_pmu.c:816:11: warning: returning ‘void *’ from a function with return type ‘int’ makes integer from pointer without a cast [-Wint-conversion]
> + 816 | return ERR_PTR(-EINVAL);
> + | ^~~~~~~~~~~~~~~~
> +drivers/perf/arm_smmuv3_pmu.c:816:39: warning: incorrect type in return expression (different base types) [sparse]
> +drivers/perf/arm_smmuv3_pmu.c:816:39: expected int [sparse]
> +drivers/perf/arm_smmuv3_pmu.c:816:39: got void * [sparse]
> +drivers/perf/arm_smmuv3_pmu.c:819:11: warning: returning ‘void *’ from a function with return type ‘int’ makes integer from pointer without a cast [-Wint-conversion]
> + 819 | return ERR_PTR(-ENOMEM);
> + | ^~~~~~~~~~~~~~~~
> +drivers/perf/arm_smmuv3_pmu.c:819:39: warning: incorrect type in return expression (different base types) [sparse]
> +drivers/perf/arm_smmuv3_pmu.c:819:39: expected int [sparse]
> +drivers/perf/arm_smmuv3_pmu.c:819:39: got void * [sparse]
>
> Will
>
> .
>

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