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  1. 12 Sep, 2014 2 commits
    • Lorenzo Pieralisi's avatar
      arm64: kernel: refactor the CPU suspend API for retention states · 714f5992
      Lorenzo Pieralisi authored 
      CPU suspend is the standard kernel interface to be used to enter
low-power states on ARM64 systems. Current cpu_suspend implementation
by default assumes that all low power states are losing the CPU context,
so the CPU registers must be saved and cleaned to DRAM upon state
entry. Furthermore, the current cpu_suspend() implementation assumes
that if the CPU suspend back-end method returns when called, this has
to be considered an error regardless of the return code (which can be
successful) since the CPU was not expected to return from a code path that
is different from cpu_resume code path - eg returning from the reset vector.

All in all this means that the current API does not cope well with low-power
states that preserve the CPU context when entered (ie retention states),
since first of all the context is saved for nothing on state entry for
those states and a successful state entry can return as a normal function
return, which is considered an error by the current CPU suspend
implementation.

This patch refactors the cpu_suspend() API so that it can be split in
two separate functionalities. The arm64 cpu_suspend API just provides
a wrapper around CPU suspend operation hook. A new function is
introduced (for architecture code use only) for states that require
context saving upon entry:

__cpu_suspend(unsigned long arg, int (*fn)(unsigned long))

__cpu_suspend() saves the context on function entry and calls the
so called suspend finisher (ie fn) to complete the suspend operation.
The finisher is not expected to return, unless it fails in which case
the error is propagated back to the __cpu_suspend caller.

The API refactoring results in the following pseudo code call sequence for a
suspending CPU, when triggered from a kernel subsystem:

/*
 * int cpu_suspend(unsigned long idx)
 * @idx: idle state index
 */
{
-> cpu_suspend(idx)
	|---> CPU operations suspend hook called, if present
		|--> if (retention_state)
			|--> direct suspend back-end call (eg PSCI suspend)
		     else
			|--> __cpu_suspend(idx, &back_end_finisher);
}

By refactoring the cpu_suspend API this way, the CPU operations back-end
has a chance to detect whether idle states require state saving or not
and can call the required suspend operations accordingly either through
simple function call or indirectly through __cpu_suspend() which carries out
state saving and suspend finisher dispatching to complete idle state entry.
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: default avatarHanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      714f5992
    • Lorenzo Pieralisi's avatar
      Documentation: arm: define DT idle states bindings · 3f8161b2
      Lorenzo Pieralisi authored 
      ARM based platforms implement a variety of power management schemes that
allow processors to enter idle states at run-time.
The parameters defining these idle states vary on a per-platform basis forcing
the OS to hardcode the state parameters in platform specific static tables
whose size grows as the number of platforms supported in the kernel increases
and hampers device drivers standardization.

Therefore, this patch aims at standardizing idle state device tree bindings
for ARM platforms. Bindings define idle state parameters inclusive of entry
methods and state latencies, to allow operating systems to retrieve the
configuration entries from the device tree and initialize the related power
management drivers, paving the way for common code in the kernel to deal with
idle states and removing the need for static data in current and previous
kernel versions.

ARM64 platforms require the DT to define an entry-method property
for idle states.

On system implementing PSCI as an enable-method to enter low-power
states the PSCI CPU suspend method requires the power_state parameter to
be passed to the PSCI CPU suspend function.

This parameter is specific to a power state and platform specific,
therefore must be provided by firmware to the OS in order to enable
proper call sequence.

Thus, this patch also adds a property in the PSCI bindings that
describes how the PSCI CPU suspend power_state parameter should be
defined in DT in all device nodes that rely on PSCI CPU suspend method usage.
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Acked-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: default avatarNicolas Pitre <nico@linaro.org>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
Reviewed-by: default avatarSebastian Capella <sebcape@gmail.com>
Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      3f8161b2
  3. 07 Sep, 2014 11 commits
  5. 06 Sep, 2014 6 commits
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm · 2b12164b
      Linus Torvalds authored 
      Pull kvm fixes from Paolo Bonzini:
 "A smattering of bug fixes across most architectures"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  powerpc/kvm/cma: Fix panic introduces by signed shift operation
  KVM: s390/mm: Fix guest storage key corruption in ptep_set_access_flags
  KVM: s390/mm: Fix storage key corruption during swapping
  arm/arm64: KVM: Complete WFI/WFE instructions
  ARM/ARM64: KVM: Nuke Hyp-mode tlbs before enabling MMU
  KVM: s390/mm: try a cow on read only pages for key ops
  KVM: s390: Fix user triggerable bug in dead code
      2b12164b
    • Linus Torvalds's avatar
      Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc · 56c22854
      Linus Torvalds authored 
      Pull ARM SoC fixes from Kevin Hilman:
 "Another round of fixes from arm-soc land, which are mostly DT fixes
  for:

   - OMAP: handful of DT fixes devices on newly supported hardware
   - davinci: fix 2nd EDMA channel
   - ux500: extend previous pinctrl fix to another board
   - at91: clock registration fixes, compatibility string precision

  And one more fix for event cleanup in drivers/bus/arm-ccn"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  bus: arm-ccn: Move event cleanup routine
  ARM: at91/dt: rm9200: fix usb clock definition
  ARM: at91: rm9200: fix clock registration
  ARM: at91/dt: sam9g20: set at91sam9g20 pllb driver
  ARM: dts: dra7-evm: Add vtt regulator support
  ARM: dts: dra7-evm: Fix spi1 mux documentation
  ARM: dts: am43x-epos-evm: Disable QSPI to prevent conflict with GPMC-NAND
  ARM: OMAP2+: gpmc: Don't complain if wait pin is used without r/w monitoring
  ARM: dts: am43xx-epos-evm: Don't use read/write wait monitoring
  ARM: dts: am437x-gp-evm: Don't use read/write wait monitoring
  ARM: dts: am437x-gp-evm: Use BCH16 ECC scheme instead of BCH8
  ARM: dts: am43x-epos-evm: Use BCH16 ECC scheme instead of BCH8
  ARM: dts: am4372: fix USB regs size
  ARM: dts: am437x-gp: switch i2c0 to 100KHz
  ARM: dts: dra7-evm: Fix 8th NAND partition's name
  ARM: dts: dra7-evm: Fix i2c3 pinmux and frequency
  ARM: ux500: disable msp2 node on Snowball
  ARM: edma: Fix configuration parsing for SoCs with multiple eDMA3 CC
  ARM: dts: set 'ti,set-rate-parent' for dpll4_m5x2 clock
      56c22854
    • Linus Torvalds's avatar
      Merge tag 'xfs-for-linus-3.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs · 11e97398
      Linus Torvalds authored 
      Pull xfs fixes from Dave Chinner:
 "The fixes all address recently discovered data corruption issues.

  The original Direct IO issue was discovered by Chris Mason @ Facebook
  on a production workload which mixed buffered reads with direct reads
  and writes IO to the same file.  The fix for that exposed other issues
  with page invalidation (exposed by millions of fsx operations) failing
  due to dirty buffers beyond EOF.

  Finally, the collapse_range code could also cause problems due to
  racing writeback changing the extent map while it was being shifted
  around.  The commits for that problem are simple mitigation fixes that
  prevent the problem from occuring.  A more robust fix for 3.18 that
  addresses the underlying problem is currently being worked on by
  Brian.

  Summary of fixes:
   - a direct IO read/buffered read data corruption
   - the associated fallout from the DIO data corruption fix
   - collapse range bugs that are potential data corruption issues"

* tag 'xfs-for-linus-3.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs:
  xfs: trim eofblocks before collapse range
  xfs: xfs_file_collapse_range is delalloc challenged
  xfs: don't log inode unless extent shift makes extent modifications
  xfs: use ranged writeback and invalidation for direct IO
  xfs: don't zero partial page cache pages during O_DIRECT writes
  xfs: don't zero partial page cache pages during O_DIRECT writes
  xfs: don't dirty buffers beyond EOF
      11e97398
    • Linus Torvalds's avatar
      Merge tag 'for-linus-20140905' of git://git.infradead.org/linux-mtd · 925e0ea4
      Linus Torvalds authored 
      Pull mtd fixes from Brian Norris:
 "Two trivial MTD updates for 3.17-rc4:

   - a tiny comment tweak, to kill a bunch of DocBook warnings added
     during the merge window

   - a small fixup to the OTP routines' error handling"

* tag 'for-linus-20140905' of git://git.infradead.org/linux-mtd:
  mtd: nand: fix DocBook warnings on nand_sdr_timings doc
  mtd: cfi_cmdset_0002: check return code for get_chip()
      925e0ea4
    • Thomas Gleixner's avatar
      timekeeping: Update timekeeper before updating vsyscall and pvclock · 9bf2419f
      Thomas Gleixner authored 
      The update_walltime() code works on the shadow timekeeper to make the
seqcount protected region as short as possible. But that update to the
shadow timekeeper does not update all timekeeper fields because it's
sufficient to do that once before it becomes life. One of these fields
is tkr.base_mono. That stays stale in the shadow timekeeper unless an
operation happens which copies the real timekeeper to the shadow.

The update function is called after the update calls to vsyscall and
pvclock. While not correct, it did not cause any problems because none
of the invoked update functions used base_mono.

commit cbcf2dd3 (x86: kvm: Make kvm_get_time_and_clockread()
nanoseconds based) changed that in the kvm pvclock update function, so
the stale mono_base value got used and caused kvm-clock to malfunction.

Put the update where it belongs and fix the issue.
Reported-by: default avatarChris J Arges <chris.j.arges@canonical.com>
Reported-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1409050000570.3333@nanosSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      9bf2419f
    • Thomas Gleixner's avatar
      compat: nanosleep: Clarify error handling · 849151dd
      Thomas Gleixner authored 
      The error handling in compat_sys_nanosleep() is correct, but
completely non obvious. Document it and restrict it to the
-ERESTART_RESTARTBLOCK return value for clarity.
Reported-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      849151dd
  7. 05 Sep, 2014 17 commits
  9. 04 Sep, 2014 4 commits
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