tty: pl011: Work around QDF2400 E44 stuck BUSY bit

Bug #1671600 reported by dann frazier on 2017-03-09
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
High
dann frazier
Zesty
High
dann frazier

Bug Description

The upstream commit summarizes the problem well, so I'll just paste it here:

commit d8a4995bcea168dfac8ee41c28c79109907e4fba
Author: Christopher Covington <email address hidden>
Date: Wed Feb 15 16:39:43 2017 -0500

    tty: pl011: Work around QDF2400 E44 stuck BUSY bit

    The Qualcomm Datacenter Technologies QDF2400 family of SoCs contains a
    custom (non-PrimeCell) implementation of the SBSA UART. Occasionally the
    BUSY bit in the Flag Register gets stuck as 1, erratum 44 for both 2432v1
    and 2400v1 SoCs.Checking that the Transmit FIFO Empty (TXFE) bit is 0,
    instead of checking that the BUSY bit is 1, works around the issue.

    To facilitate this substitution of flags and values, introduce
    vendor-specific inversion of Feature Register bits when UART AMBA Port
    (UAP) data is available. For the earlycon case, prior to UAP availability,
    implement alternative putc and early_write functions.

    Similar to what how ARMv8 ACPI PCI quirks are detected during MCFG parsing,
    check the OEM fields of the Serial Port Console Redirection (SPCR) ACPI
    table to determine if the current platform is known to be affected by the
    erratum.

    Signed-off-by: Christopher Covington <email address hidden>
    Acked-by: Russell King <email address hidden>
    Acked-by: Timur Tabi <email address hidden>
    Acked-by: Mark Rutland <email address hidden>
    Signed-off-by: Greg Kroah-Hartman <email address hidden>

CVE References

Seth Forshee (sforshee) on 2017-03-09
Changed in linux (Ubuntu):
status: In Progress → Fix Committed
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package linux - 4.10.0-13.15

---------------
linux (4.10.0-13.15) zesty; urgency=low

  [ Tim Gardner ]

  * Release Tracking Bug
    - LP: #1671614

  * ehci-platform needed in usb-modules udeb (LP: #1671589)
    - d-i: add ehci-platform to usb-modules

  * irqchip/gic-v3-its: Enable cacheable attribute Read-allocate hints
    (LP: #1671598)
    - irqchip/gic-v3-its: Enable cacheable attribute Read-allocate hints

  * iommu: Fix static checker warning in iommu_insert_device_resv_regions
    (LP: #1671599)
    - iommu: Fix static checker warning in iommu_insert_device_resv_regions

  * QDF2400: Fix panic introduced by erratum 1003 (LP: #1671602)
    - arm64: Avoid clobbering mm in erratum workaround on QDF2400

  * QDF2400 PCI ports require ACS quirk (LP: #1671601)
    - PCI: Add ACS quirk for Qualcomm QDF2400 and QDF2432

  * tty: pl011: Work around QDF2400 E44 stuck BUSY bit (LP: #1671600)
    - tty: pl011: Work around QDF2400 E44 stuck BUSY bit

  * CVE-2017-2636
    - tty: n_hdlc: get rid of racy n_hdlc.tbuf

  * Sync virtualbox to 5.1.16-dfsg-1 in zesty (LP: #1671470)
    - ubuntu: vbox -- Update to 5.1.16-dfsg-1

 -- Tim Gardner <email address hidden> Thu, 09 Mar 2017 06:16:24 -0700

Changed in linux (Ubuntu Zesty):
status: Fix Committed → Fix Released
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