linux-toradex.git/Documentation, branch v3.14.28

of/irq: Drop obsolete 'interrupts' vs 'interrupts-extended' text

2014-12-06T23:55:37+00:00

commit 66865de4314caca30598244b86817e774c188afa upstream.

a9ecdc0fdc54 ("of/irq: Fix lookup to use 'interrupts-extended' property
first") updated the description to say that:

  - Both 'interrupts' and 'interrupts-extended' may be present
  - Software should prefer 'interrupts-extended'
  - Software that doesn't comprehend 'interrupts-extended' may use
    'interrupts'

But there is still a paragraph at the end that prohibits having both and
says 'interrupts' should be preferred.

Remove the contradictory text.

Fixes: a9ecdc0fdc54 ("of/irq: Fix lookup to use 'interrupts-extended' property first")
Signed-off-by: Bjorn Helgaas 
Acked-by: Brian Norris 
Acked-by: Mark Rutland 
Signed-off-by: Rob Herring 
Signed-off-by: Greg Kroah-Hartman

ata: sata_rcar: Disable DIPM mode for r8a7790 ES1

2014-11-21T17:23:02+00:00

commit aa1cf25887099bba68f1f3879c0d394e08b8779f upstream.

Unlike other SATA R-Car r8a7790 controllers the r8a7790 ES1 SATA R-Car
controller needs to be run with DIPM disabled.

Signed-off-by: Simon Horman 
Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

Documentation: lzo: document part of the encoding

2014-10-30T16:38:22+00:00

commit d98a0526434d27e261f622cf9d2e0028b5ff1a00 upstream.

Add a complete description of the LZO format as processed by the
decompressor. I have not found a public specification of this format
hence this analysis, which will be used to better understand the code.

Cc: Willem Pinckaers 
Cc: "Don A. Bailey" 
Signed-off-by: Willy Tarreau 
Signed-off-by: Greg Kroah-Hartman

kvm: fix potentially corrupt mmio cache

2014-10-30T16:38:19+00:00

commit ee3d1570b58677885b4552bce8217fda7b226a68 upstream.

vcpu exits and memslot mutations can run concurrently as long as the
vcpu does not aquire the slots mutex. Thus it is theoretically possible
for memslots to change underneath a vcpu that is handling an exit.

If we increment the memslot generation number again after
synchronize_srcu_expedited(), vcpus can safely cache memslot generation
without maintaining a single rcu_dereference through an entire vm exit.
And much of the x86/kvm code does not maintain a single rcu_dereference
of the current memslots during each exit.

We can prevent the following case:

   vcpu (CPU 0)                             | thread (CPU 1)
--------------------------------------------+--------------------------
1  vm exit                                  |
2  srcu_read_unlock(&kvm->srcu)             |
3  decide to cache something based on       |
     old memslots                           |
4                                           | change memslots
                                            | (increments generation)
5                                           | synchronize_srcu(&kvm->srcu);
6  retrieve generation # from new memslots  |
7  tag cache with new memslot generation    |
8  srcu_read_unlock(&kvm->srcu)             |
...                                         |
                       |
...                                         |
                                  |
                                            |

By incrementing the generation after synchronizing with kvm->srcu readers,
we ensure that the generation retrieved in (6) will become invalid soon
after (8).

Keeping the existing increment is not strictly necessary, but we
do keep it and just move it for consistency from update_memslots to
install_new_memslots.  It invalidates old cached MMIOs immediately,
instead of having to wait for the end of synchronize_srcu_expedited,
which makes the code more clearly correct in case CPU 1 is preempted
right after synchronize_srcu() returns.

To avoid halving the generation space in SPTEs, always presume that the
low bit of the generation is zero when reconstructing a generation number
out of an SPTE.  This effectively disables MMIO caching in SPTEs during
the call to synchronize_srcu_expedited.  Using the low bit this way is
somewhat like a seqcount---where the protected thing is a cache, and
instead of retrying we can simply punt if we observe the low bit to be 1.

Signed-off-by: David Matlack 
Reviewed-by: Xiao Guangrong 
Reviewed-by: David Matlack 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Greg Kroah-Hartman

of/irq: Fix lookup to use 'interrupts-extended' property first

2014-10-05T21:52:10+00:00

commit a9ecdc0fdc54aa499604dbd43132988effcac9b4 upstream.

In case the Device Tree blob passed by the boot agent supplies both an
'interrupts-extended' and an 'interrupts' property in order to allow for
older kernels to be usable, prefer the new-style 'interrupts-extended'
property which conveys a lot more information.

This allows us to have bootloaders willingly maintaining backwards
compatibility with older kernels without entirely deprecating the
'interrupts' property.

Update the bindings documentation to describe a situation where both the
'interrupts-extended' and the 'interrupts' property are present, and
which one takes precedence over the other.

Acked-by: Rob Herring 
Signed-off-by: Brian Norris 
Signed-off-by: Florian Fainelli 
Signed-off-by: Grant Likely 
Signed-off-by: Greg Kroah-Hartman

ASoC: axi: Fix ADI AXI SPDIF specification

2014-09-17T16:19:18+00:00

commit d1555c407a65db42126b295425379acb393ba83a upstream.

The specification requires compatible = "adi,axi-spdif-1.00.a" but
driver and example and file name indicate "adi,axi-spdif-tx-1.00.a".
Change the specification to match the implementation.

Acked-by: Lars-Peter Clausen 
Reviewed-by: Michal Simek 
Fixes: d7b528eff927 ("dt: Add bindings documentation for the ADI AXI-SPDIF audio controller")
Signed-off-by: Andreas Färber 
Signed-off-by: Mark Brown 
Signed-off-by: Greg Kroah-Hartman

ALSA: virtuoso: add Xonar Essence STX II support

2014-09-05T23:34:13+00:00

commit f42bb22243d2ae264d721b055f836059fe35321f upstream.

Just add the PCI ID for the STX II.  It appears to work the same as the
STX, except for the addition of the not-yet-supported daughterboard.

Tested-by: Mario 
Tested-by: corubba 
Signed-off-by: Clemens Ladisch 
Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

stable_kernel_rules: Add pointer to netdev-FAQ for network patches

2014-09-05T23:34:12+00:00

commit b76fc285337b6b256e9ba20a40cfd043f70c27af upstream.

Stable_kernel_rules should point submitters of network stable patches to the
netdev_FAQ.txt as requests for stable network patches should go to netdev
first.

Signed-off-by: Dave Chiluk 
Signed-off-by: Greg Kroah-Hartman

x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack

2014-08-07T21:52:38+00:00

commit 3891a04aafd668686239349ea58f3314ea2af86b upstream.

The IRET instruction, when returning to a 16-bit segment, only
restores the bottom 16 bits of the user space stack pointer.  This
causes some 16-bit software to break, but it also leaks kernel state
to user space.  We have a software workaround for that ("espfix") for
the 32-bit kernel, but it relies on a nonzero stack segment base which
is not available in 64-bit mode.

In checkin:

    b3b42ac2cbae x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels

we "solved" this by forbidding 16-bit segments on 64-bit kernels, with
the logic that 16-bit support is crippled on 64-bit kernels anyway (no
V86 support), but it turns out that people are doing stuff like
running old Win16 binaries under Wine and expect it to work.

This works around this by creating percpu "ministacks", each of which
is mapped 2^16 times 64K apart.  When we detect that the return SS is
on the LDT, we copy the IRET frame to the ministack and use the
relevant alias to return to userspace.  The ministacks are mapped
readonly, so if IRET faults we promote #GP to #DF which is an IST
vector and thus has its own stack; we then do the fixup in the #DF
handler.

(Making #GP an IST exception would make the msr_safe functions unsafe
in NMI/MC context, and quite possibly have other effects.)

Special thanks to:

- Andy Lutomirski, for the suggestion of using very small stack slots
  and copy (as opposed to map) the IRET frame there, and for the
  suggestion to mark them readonly and let the fault promote to #DF.
- Konrad Wilk for paravirt fixup and testing.
- Borislav Petkov for testing help and useful comments.

Reported-by: Brian Gerst 
Signed-off-by: H. Peter Anvin 
Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com
Cc: Konrad Rzeszutek Wilk 
Cc: Borislav Petkov 
Cc: Andrew Lutomriski 
Cc: Linus Torvalds 
Cc: Dirk Hohndel 
Cc: Arjan van de Ven 
Cc: comex 
Cc: Alexander van Heukelum 
Cc: Boris Ostrovsky 
Cc:  # consider after upstream merge
Signed-off-by: Greg Kroah-Hartman

intel_pstate: Update documentation of {max,min}_perf_pct sysfs files

2014-07-17T23:21:05+00:00

commit 41629a8233470325bfbb60377f555f9e8acc879f upstream.

Update documentation to make the interpretation of the values clearer

Link: https://bugzilla.kernel.org/show_bug.cgi?id=64251
Signed-off-by: Dirk Brandewie 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman