From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: Re: [PATCH v6 3/4] iommu/arm-smmu: Add global/context fault implementation hooks Date: Tue, 23 Jun 2020 12:30:16 +0100 Message-ID: <2dda4530-39cc-d549-1124-26337dd9afbe@arm.com> References: <20200604234414.21912-1-vdumpa@nvidia.com> <20200604234414.21912-4-vdumpa@nvidia.com> <20200623083643.GB4098287@ulmo> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20200623083643.GB4098287@ulmo> Content-Language: en-GB Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Thierry Reding , Krishna Reddy Cc: snikam-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, mperttunen-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, bhuntsman-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, will-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, praithatha-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, talho-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, nicolinc-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, yhsu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, bbiswas-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org List-Id: linux-tegra@vger.kernel.org On 2020-06-23 09:36, Thierry Reding wrote: [...] >> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c >> index 243bc4cb2705b..d720e1e191176 100644 >> --- a/drivers/iommu/arm-smmu.c >> +++ b/drivers/iommu/arm-smmu.c >> @@ -673,6 +673,7 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, >> enum io_pgtable_fmt fmt; >> struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); >> struct arm_smmu_cfg *cfg = &smmu_domain->cfg; >> + irqreturn_t (*context_fault)(int irq, void *dev); >> >> mutex_lock(&smmu_domain->init_mutex); >> if (smmu_domain->smmu) >> @@ -835,7 +836,9 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, >> * handler seeing a half-initialised domain state. >> */ >> irq = smmu->irqs[smmu->num_global_irqs + cfg->irptndx]; >> - ret = devm_request_irq(smmu->dev, irq, arm_smmu_context_fault, >> + context_fault = (smmu->impl && smmu->impl->context_fault) ? >> + smmu->impl->context_fault : arm_smmu_context_fault; > > A simpler way might have been to assign arm_smmu_context_fault to all > implementations. That way we wouldn't have to perform this check here > and instead just always using smmu->impl->context_fault. But smmu->impl can still be NULL... Everything in impl, including the presence of impl itself, is optional, so the notion of overriding a default with the same default doesn't really make much sense, and would go against the pattern everywhere else. Robin. >> + ret = devm_request_irq(smmu->dev, irq, context_fault, >> IRQF_SHARED, "arm-smmu-context-fault", domain); >> if (ret < 0) { >> dev_err(smmu->dev, "failed to request context IRQ %d (%u)\n", >> @@ -2107,6 +2110,7 @@ static int arm_smmu_device_probe(struct platform_device *pdev) >> struct arm_smmu_device *smmu; >> struct device *dev = &pdev->dev; >> int num_irqs, i, err; >> + irqreturn_t (*global_fault)(int irq, void *dev); >> >> smmu = devm_kzalloc(dev, sizeof(*smmu), GFP_KERNEL); >> if (!smmu) { >> @@ -2193,9 +2197,12 @@ static int arm_smmu_device_probe(struct platform_device *pdev) >> smmu->num_context_irqs = smmu->num_context_banks; >> } >> >> + global_fault = (smmu->impl && smmu->impl->global_fault) ? >> + smmu->impl->global_fault : arm_smmu_global_fault; >> + > > Same as above. > > Thierry >