Skip to content

L
linux
Switch branch/tag
  1. 30 Sep, 2013 6 commits
    • Lorenzo Pieralisi's avatar
      ARM: vexpress: tc2: fix hotplug/idle/kexec race on cluster power down · 64270d82
      Lorenzo Pieralisi authored 
      On the TC2 testchip, when all CPUs in a cluster enter standbywfi
and commit a power down request, the power controller will wait
for standbywfil2 coming from L2 cache controller to shut the
cluster down.
By the time all CPUs in a cluster commit a power down request
and enter wfi, the power controller cannot backtrack, or put it
another way, a CPU must not be allowed to complete execution
independently of the power controller, the only way for it to
resume properly must be upon wake-up IRQ pending and subsequent
reset triggered from the power controller.

Current MCPM back-end for TC2 disables the GIC CPU IF only when
power down is committed through the tc2_pm_suspend() method, that
makes sense since a suspended CPU is still online and can receive
interrupts whereas a hotplugged CPU, since it is offline,
migrated all IRQs and shutdown the per-CPU peripherals, hence
their PPIs.

The flaw with this reasoning is the following. If all CPUs in
a clusters are entering a power down state either through CPU
idle or CPU hotplug, when the last man successfully completes
the MCPM power down sequence (and executes wfi), power controller
waits for L2 wfi signal to quiesce the cluster and shut it down.
If, when all CPUs are sitting in wfi, an online CPU hotplugs back
in one of the CPUs in the cluster being shutdown, that CPU
receives an IPI that causes wfi to complete (since tc2_pm_down()
method does not disable the GIC CPU IF in that case - CPU being
hotplugged out, not idle) and the power controller will never see
the stanbywfil2 signal coming from L2 that is required for
shutdown to happen and the system deadlocks.

Further to this issue, kexec hotplugs secondary CPUs out during
kernel reload/restart.
Because kexec may (deliberately) trash the old kernel text, it is
not OK for CPUs to follow the MCPM soft reboot path, since
instructions after the WFI may have been replaced by kexec.

If tc2_pm_down() does not disable the GIC cpu interface, there is a
race between CPU powerdown in the old kernel and the IPI from the
new kernel that triggers secondary boot, particularly if the
powerdown is slow (due to L2 cache cleaning for example).  If the
new kernel wins the race, the affected CPU(s) will not really be
reset and may execute garbage after the WFI.

The only solution to this problem consists in disabling the GIC
CPU IF on a CPU committed to power down regardless of the power
down entry method (CPU hotplug or CPU idle). This way, CPU wake-up
is under power controller control, which prevents unexpected wfi
exit caused by a pending IRQ.

This patch moves the GIC CPU IF disable call in the TC2 MCPM
implementation from the tc2_pm_suspend() method to the
tc2_pm_down() method to fix the mentioned race condition(s).
Reviewed-by: default avatarDave Martin <Dave.Martin@arm.com>
Tested-by: Dave Martin <Dave.Martin@arm.com> (for kexec)
Signed-off-by: default avatarSudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: default avatarNicolas Pitre <nico@linaro.org>
Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
      64270d82
    • Olof Johansson's avatar
      Merge tag 'renesas-fixes4-for-v3.12' of... · f1bb7cd5
      Olof Johansson authored 
      Merge tag 'renesas-fixes4-for-v3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas into fixes

From Simon Horman:
Fourth Round of Renesas ARM based SoC fixes for v3.12

* Remove unused #gpio-ranges-cells DT property

* Remove usage of deprecated #gpio-range-cells DT property
  from GPIO R-Car

  Property was deprecated in v3.11-rc2

* Correct ether pinctl naming for armadillo800eva board

  Regression introduced in v3.10-rc5

* Add Micrel KSZ8041 PHY fixup to lager board

  This resolves a problem that has been present since 3.11-rc2

* Update SDHI DT compatibility string to the <unit>-<soc> format

  This makes compatibility strings consistent across all renesas
  hardware which currently supports DT.

  The bindings which are being updated where intorodiced on
  a per-SoC basis starting in v3.8-rc7. They may have
  been internally consistent when originally added.

* tag 'renesas-fixes4-for-v3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas:
  ARM: shmobile: Remove #gpio-ranges-cells DT property
  gpio: rcar: Remove #gpio-range-cells DT property usage
  ARM: shmobile: armadillo: fixup ether pinctrl naming
  ARM: shmobile: Lager: add Micrel KSZ8041 PHY fixup
  ARM: shmobile: update SDHI DT compatibility string to the <unit>-<soc> format
Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
      f1bb7cd5
    • Renwei Wu's avatar
      ARM: dts: sirf: fix interrupt and dma prop of VIP for prima2 and atlas6 · 262bcc1d
      Renwei Wu authored 
      the current dts is lacking interrupt and dma prop for video input
processor of prima2 and atlas6, this patch fixes it.
Signed-off-by: default avatarRenwei Wu <Renwei.Wu@csr.com>
Signed-off-by: default avatarBarry Song <Baohua.Song@csr.com>
Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
      262bcc1d
    • Barry Song's avatar
      ARM: dts: sirf: fix the ranges of peri-iobrg of prima2 · 9e85b9d1
      Barry Song authored 
      we lost an address range <0x56000000 0x56000000 0x1b00000> for peri-iobg
of prima2.
Signed-off-by: default avatarBarry Song <Baohua.Song@csr.com>
Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
      9e85b9d1
    • Barry Song's avatar
      ARM: dts: makefile: build atlas6-evb.dtb for ARCH_ATLAS6 · 3349a4b9
      Barry Song authored 
      Makefile missed to include atlas6-evb.dtb for ARCH_ATLAS6.
Signed-off-by: default avatarBarry Song <Baohua.Song@csr.com>
Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
      3349a4b9
    • Qipan Li's avatar
      ARM: dts: sirf: fix fifosize, clks, dma channels for UART · a1369978
      Qipan Li authored 
      sirf uart and usp-based uart driver with full dma support has
hit 3.12, here we fix the fifosize, dma channels for some HW
prop.
Signed-off-by: default avatarQipan Li <Qipan.Li@csr.com>
Signed-off-by: default avatarBarry Song <Baohua.Song@csr.com>
Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
      a1369978
  3. 26 Sep, 2013 2 commits
  5. 22 Sep, 2013 3 commits
  7. 21 Sep, 2013 2 commits
  9. 20 Sep, 2013 3 commits
  11. 19 Sep, 2013 5 commits
  13. 18 Sep, 2013 19 commits
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7