From: "Isaac J. Manjarres" <isaacm@codeaurora.org>
To: Will Deacon <will@kernel.org>
Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
Bjorn Helgaas <bhelgaas@google.com>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH 7/7] iommu/arm-smmu: Allow building as a module
Date: Mon, 4 Nov 2019 11:34:00 -0800 [thread overview]
Message-ID: <20191104193400.GA24983@codeaurora.org> (raw)
In-Reply-To: <20191030145112.19738-8-will@kernel.org>
On Wed, Oct 30, 2019 at 02:51:12PM +0000, Will Deacon wrote:
> By conditionally dropping support for the legacy binding and exporting
> the newly introduced 'arm_smmu_impl_init()' function we can allow the
> ARM SMMU driver to be built as a module.
>
> Signed-off-by: Will Deacon <will@kernel.org>
> ---
> drivers/iommu/Kconfig | 14 ++++++++-
> drivers/iommu/arm-smmu-impl.c | 6 ++++
> drivers/iommu/arm-smmu.c | 54 +++++++++++++++++++++--------------
> 3 files changed, 51 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index 7583d47fc4d5..02703f51e533 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -350,7 +350,7 @@ config SPAPR_TCE_IOMMU
>
> # ARM IOMMU support
> config ARM_SMMU
> - bool "ARM Ltd. System MMU (SMMU) Support"
> + tristate "ARM Ltd. System MMU (SMMU) Support"
> depends on (ARM64 || ARM) && MMU
> select IOMMU_API
> select IOMMU_IO_PGTABLE_LPAE
> @@ -362,6 +362,18 @@ config ARM_SMMU
> Say Y here if your SoC includes an IOMMU device implementing
> the ARM SMMU architecture.
>
> +config ARM_SMMU_LEGACY_DT_BINDINGS
> + bool "Support the legacy \"mmu-masters\" devicetree bindings"
> + depends on ARM_SMMU=y && OF
> + help
> + Support for the badly designed and deprecated \"mmu-masters\"
> + devicetree bindings. This allows some DMA masters to attach
> + to the SMMU but does not provide any support via the DMA API.
> + If you're lucky, you might be able to get VFIO up and running.
> +
> + If you say Y here then you'll make me very sad. Instead, say N
> + and move your firmware to the utopian future that was 2016.
> +
> config ARM_SMMU_DISABLE_BYPASS_BY_DEFAULT
> bool "Default to disabling bypass on ARM SMMU v1 and v2"
> depends on ARM_SMMU
> diff --git a/drivers/iommu/arm-smmu-impl.c b/drivers/iommu/arm-smmu-impl.c
> index 5c87a38620c4..2f82d40317d6 100644
> --- a/drivers/iommu/arm-smmu-impl.c
> +++ b/drivers/iommu/arm-smmu-impl.c
> @@ -5,6 +5,7 @@
> #define pr_fmt(fmt) "arm-smmu: " fmt
>
> #include <linux/bitfield.h>
> +#include <linux/module.h>
> #include <linux/of.h>
>
> #include "arm-smmu.h"
> @@ -172,3 +173,8 @@ struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu)
>
> return smmu;
> }
> +EXPORT_SYMBOL_GPL(arm_smmu_impl_init);
> +
> +MODULE_DESCRIPTION("IOMMU quirks for ARM architected SMMU implementations");
> +MODULE_AUTHOR("Robin Murphy <robin.murphy@arm.com>");
> +MODULE_LICENSE("GPL v2");
Hi Will,
A minor comment: I was curious about why arm-smmu.c and arm-smmu-impl.c
were being compiled as two separate modules, as opposed to combining
them into one module? The latter approach seemed more appropriate, given
that arm-smmu-impl doesn't offer much as a module on its own. Thoughts?
--Isaac
next prev parent reply other threads:[~2019-11-04 19:34 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-30 14:51 [PATCH 0/7] iommu: Permit modular builds of ARM SMMU[v3] drivers Will Deacon
2019-10-30 14:51 ` [PATCH 1/7] drivers/iommu: Export core IOMMU API symbols to permit modular drivers Will Deacon
2019-10-30 14:51 ` [PATCH 2/7] iommu/of: Request ACS from the PCI core when configuring IOMMU linkage Will Deacon
2019-10-30 14:51 ` [PATCH 3/7] PCI: Export pci_ats_disabled() as a GPL symbol to modules Will Deacon
2019-10-30 20:30 ` Bjorn Helgaas
2019-10-30 14:51 ` [PATCH 4/7] Revert "iommu/arm-smmu: Make arm-smmu-v3 explicitly non-modular" Will Deacon
2019-10-30 14:51 ` [PATCH 5/7] iommu/arm-smmu-v3: Allow building as a module Will Deacon
2019-10-30 19:31 ` Joerg Roedel
2019-10-31 15:42 ` Will Deacon
2019-11-04 19:15 ` Jean-Philippe Brucker
2019-11-08 14:54 ` Will Deacon
2019-11-05 12:15 ` Joerg Roedel
2019-11-08 11:03 ` Will Deacon
2019-10-30 14:51 ` [PATCH 6/7] Revert "iommu/arm-smmu: Make arm-smmu explicitly non-modular" Will Deacon
2019-10-30 23:09 ` Jordan Crouse
2019-10-31 12:03 ` Will Deacon
2019-10-31 15:32 ` Jordan Crouse
2019-10-30 14:51 ` [PATCH 7/7] iommu/arm-smmu: Allow building as a module Will Deacon
2019-10-30 15:22 ` Rob Herring
2019-10-30 15:26 ` Will Deacon
2019-10-30 15:33 ` Robin Murphy
2019-11-04 19:34 ` Isaac J. Manjarres [this message]
2019-11-07 12:48 ` Will Deacon
2019-10-30 15:35 ` [PATCH 0/7] iommu: Permit modular builds of ARM SMMU[v3] drivers Robin Murphy
2019-10-30 15:54 ` Will Deacon
2019-10-31 0:57 ` Saravana Kannan
2019-10-31 19:37 ` Jean-Philippe Brucker
2019-10-31 23:34 ` Saravana Kannan
2019-11-01 10:27 ` John Garry
2019-11-01 21:13 ` Saravana Kannan
2019-11-04 12:16 ` John Garry
2019-11-04 13:29 ` Robin Murphy
2019-11-07 6:11 ` Saravana Kannan
2019-11-07 9:13 ` Jean-Philippe Brucker
2019-11-07 6:02 ` Saravana Kannan
2019-11-01 11:41 ` Jean-Philippe Brucker
2019-11-01 12:28 ` Lorenzo Pieralisi
2019-11-01 21:26 ` Saravana Kannan
2019-11-04 11:43 ` Lorenzo Pieralisi
2019-11-07 5:55 ` Saravana Kannan
2019-11-01 17:21 ` Will Deacon
2019-11-04 7:54 ` Jean-Philippe Brucker
2019-11-07 6:16 ` Saravana Kannan
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