From: Robin Murphy <robin.murphy@arm.com> To: will@kernel.org Cc: iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH] iommu/arm-smmu: Improve SMR mask test Date: Fri, 10 Jan 2020 15:25:02 +0000 [thread overview] Message-ID: <2e0f837b38671a322d33a18b7447b95ac2fba796.1578669732.git.robin.murphy@arm.com> (raw) Make the SMR mask test more robust against SMR0 being live at probe time, which might happen once we start supporting firmware reservations for framebuffers and suchlike. Signed-off-by: Robin Murphy <robin.murphy@arm.com> --- drivers/iommu/arm-smmu.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 4f1a350d9529..df6490bc7700 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -946,23 +946,36 @@ static void arm_smmu_write_sme(struct arm_smmu_device *smmu, int idx) static void arm_smmu_test_smr_masks(struct arm_smmu_device *smmu) { u32 smr; + int i; if (!smmu->smrs) return; - + /* + * If we've had to accommodate firmware memory regions, we may + * have live SMRs by now; tread carefully... + * + * Somewhat perversely, not having a free SMR for this test implies we + * can get away without it anyway, as we'll only be able to 'allocate' + * these SMRs for the ID/mask values we're already trusting to be OK. + */ + for (i = 0; i < smmu->num_mapping_groups; i++) + if (!smmu->smrs[i].valid) + goto smr_ok; + return; +smr_ok: /* * SMR.ID bits may not be preserved if the corresponding MASK * bits are set, so check each one separately. We can reject * masters later if they try to claim IDs outside these masks. */ smr = FIELD_PREP(SMR_ID, smmu->streamid_mask); - arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_SMR(0), smr); - smr = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_SMR(0)); + arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_SMR(i), smr); + smr = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_SMR(i)); smmu->streamid_mask = FIELD_GET(SMR_ID, smr); smr = FIELD_PREP(SMR_MASK, smmu->streamid_mask); - arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_SMR(0), smr); - smr = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_SMR(0)); + arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_SMR(i), smr); + smr = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_SMR(i)); smmu->smr_mask_mask = FIELD_GET(SMR_MASK, smr); } -- 2.23.0.dirty _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
WARNING: multiple messages have this Message-ID (diff)
From: Robin Murphy <robin.murphy@arm.com> To: will@kernel.org Cc: iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH] iommu/arm-smmu: Improve SMR mask test Date: Fri, 10 Jan 2020 15:25:02 +0000 [thread overview] Message-ID: <2e0f837b38671a322d33a18b7447b95ac2fba796.1578669732.git.robin.murphy@arm.com> (raw) Make the SMR mask test more robust against SMR0 being live at probe time, which might happen once we start supporting firmware reservations for framebuffers and suchlike. Signed-off-by: Robin Murphy <robin.murphy@arm.com> --- drivers/iommu/arm-smmu.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 4f1a350d9529..df6490bc7700 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -946,23 +946,36 @@ static void arm_smmu_write_sme(struct arm_smmu_device *smmu, int idx) static void arm_smmu_test_smr_masks(struct arm_smmu_device *smmu) { u32 smr; + int i; if (!smmu->smrs) return; - + /* + * If we've had to accommodate firmware memory regions, we may + * have live SMRs by now; tread carefully... + * + * Somewhat perversely, not having a free SMR for this test implies we + * can get away without it anyway, as we'll only be able to 'allocate' + * these SMRs for the ID/mask values we're already trusting to be OK. + */ + for (i = 0; i < smmu->num_mapping_groups; i++) + if (!smmu->smrs[i].valid) + goto smr_ok; + return; +smr_ok: /* * SMR.ID bits may not be preserved if the corresponding MASK * bits are set, so check each one separately. We can reject * masters later if they try to claim IDs outside these masks. */ smr = FIELD_PREP(SMR_ID, smmu->streamid_mask); - arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_SMR(0), smr); - smr = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_SMR(0)); + arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_SMR(i), smr); + smr = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_SMR(i)); smmu->streamid_mask = FIELD_GET(SMR_ID, smr); smr = FIELD_PREP(SMR_MASK, smmu->streamid_mask); - arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_SMR(0), smr); - smr = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_SMR(0)); + arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_SMR(i), smr); + smr = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_SMR(i)); smmu->smr_mask_mask = FIELD_GET(SMR_MASK, smr); } -- 2.23.0.dirty _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2020-01-10 15:26 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-01-10 15:25 Robin Murphy [this message] 2020-01-10 15:25 ` [PATCH] iommu/arm-smmu: Improve SMR mask test Robin Murphy
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