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[PATCH v2 0/6] Add support for privileged mappings

From Mitchel Humpherys <mitchelh@codeaurora.org>
Newsgroups linux.kernel
Subject [PATCH v2 0/6] Add support for privileged mappings
Date 2016-07-09 04:10 +0200
Message-ID <rSPSp-4T7-1@gated-at.bofh.it> (permalink)
Organization linux.* mail to news gateway

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The following patch to the ARM SMMU driver:

    commit d346180e70b91b3d5a1ae7e5603e65593d4622bc
    Author: Robin Murphy <robin.murphy@arm.com>
    Date:   Tue Jan 26 18:06:34 2016 +0000
    
        iommu/arm-smmu: Treat all device transactions as unprivileged

started forcing all SMMU transactions to come through as "unprivileged".
The rationale given was that:

  (1) There is no way in the IOMMU API to even request privileged mappings.

  (2) It's difficult to implement a DMA mapper that correctly models the
      ARM VMSAv8 behavior of unprivileged-writeable =>
      privileged-execute-never.

This series rectifies (1) by introducing an IOMMU API for privileged
mappings and implements it in io-pgtable-arm.

This series rectifies (2) by introducing a new dma attribute
(DMA_ATTR_PRIVILEGED_EXECUTABLE) for users of the DMA API that need
privileged, executable mappings, and implements it in the arm64 IOMMU DMA
mapper.  The one known user (pl330.c) is converted over to the new
attribute.

Jordan and Jeremy can provide more info on the use case if needed, but the
high level is that it's a security feature to prevent attacks such as [1].

[1] https://github.com/robclark/kilroy

Changelog:

  v1..v2

    - Added a new DMA attribute to make executable privileged mappings
      work, and use that in the pl330 driver (suggested by Will).


Jeremy Gebben (1):
  iommu/io-pgtable-arm: add support for the IOMMU_PRIV flag

Mitchel Humpherys (5):
  iommu: add IOMMU_PRIV attribute
  Revert "iommu/arm-smmu: Treat all device transactions as unprivileged"
  common: DMA-mapping: add DMA_ATTR_PRIVILEGED_EXECUTABLE attribute
  arm64/dma-mapping: Implement DMA_ATTR_PRIVILEGED_EXECUTABLE
  dmaengine: pl330: Make sure microcode is privileged-executable

 Documentation/DMA-attributes.txt |  9 +++++++++
 arch/arm64/mm/dma-mapping.c      |  6 +++---
 drivers/dma/pl330.c              |  7 +++++--
 drivers/iommu/arm-smmu.c         |  5 +----
 drivers/iommu/dma-iommu.c        | 15 +++++++++++----
 drivers/iommu/io-pgtable-arm.c   | 16 +++++++++++-----
 include/linux/dma-attrs.h        |  1 +
 include/linux/dma-iommu.h        |  3 ++-
 include/linux/iommu.h            |  1 +
 9 files changed, 44 insertions(+), 19 deletions(-)

-- 
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

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Thread

[PATCH v2 0/6] Add support for privileged mappings Mitchel Humpherys <mitchelh@codeaurora.org> - 2016-07-09 04:10 +0200
  [PATCH v2 5/6] arm64/dma-mapping: Implement DMA_ATTR_PRIVILEGED_EXECUTABLE Mitchel Humpherys <mitchelh@codeaurora.org> - 2016-07-09 04:10 +0200
    Re: [PATCH v2 5/6] arm64/dma-mapping: Implement  DMA_ATTR_PRIVILEGED_EXECUTABLE Robin Murphy <robin.murphy@arm.com> - 2016-07-11 17:10 +0200
  [PATCH v2 3/6] Revert "iommu/arm-smmu: Treat all device transactions as unprivileged" Mitchel Humpherys <mitchelh@codeaurora.org> - 2016-07-09 04:10 +0200
    Re: [PATCH v2 3/6] Revert "iommu/arm-smmu: Treat all device  transactions as unprivileged" Robin Murphy <robin.murphy@arm.com> - 2016-07-11 16:30 +0200
  [PATCH v2 4/6] common: DMA-mapping: add DMA_ATTR_PRIVILEGED_EXECUTABLE attribute Mitchel Humpherys <mitchelh@codeaurora.org> - 2016-07-09 04:10 +0200
    Re: [PATCH v2 4/6] common: DMA-mapping: add  DMA_ATTR_PRIVILEGED_EXECUTABLE attribute Robin Murphy <robin.murphy@arm.com> - 2016-07-11 16:50 +0200
  [PATCH v2 2/6] iommu/io-pgtable-arm: add support for the IOMMU_PRIV flag Mitchel Humpherys <mitchelh@codeaurora.org> - 2016-07-09 04:10 +0200
    Re: [PATCH v2 2/6] iommu/io-pgtable-arm: add support for the  IOMMU_PRIV flag Robin Murphy <robin.murphy@arm.com> - 2016-07-11 16:20 +0200
  [PATCH v2 1/6] iommu: add IOMMU_PRIV attribute Mitchel Humpherys <mitchelh@codeaurora.org> - 2016-07-09 04:10 +0200
    Re: [PATCH v2 1/6] iommu: add IOMMU_PRIV attribute Robin Murphy <robin.murphy@arm.com> - 2016-07-11 16:10 +0200
  [PATCH v2 6/6] dmaengine: pl330: Make sure microcode is privileged-executable Mitchel Humpherys <mitchelh@codeaurora.org> - 2016-07-09 04:10 +0200
    Re: [PATCH v2 6/6] dmaengine: pl330: Make sure microcode is  privileged-executable Robin Murphy <robin.murphy@arm.com> - 2016-07-11 17:30 +0200
  Re: [PATCH v2 0/6] Add support for privileged mappings Robin Murphy <robin.murphy@arm.com> - 2016-07-11 16:10 +0200
    Re: [PATCH v2 0/6] Add support for privileged mappings Jordan Crouse <jcrouse@codeaurora.org> - 2016-07-11 17:10 +0200

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