linux-stable.git/Documentation, branch v4.9.232

media: dvb_frontend: fix return values for FE_SET_PROPERTY

2020-06-30T19:38:35+00:00

commit 259a41d9ae8f3689742267f340ad2b159d00b302 upstream

There are several problems with regards to the return of
FE_SET_PROPERTY. The original idea were to return per-property
return codes via tvp->result field, and to return an updated
set of values.

However, that never worked. What's actually implemented is:

- the FE_SET_PROPERTY implementation doesn't call .get_frontend
  callback in order to get the actual parameters after return;

- the tvp->result field is only filled if there's no error.
  So, it is always filled with zero;

- FE_SET_PROPERTY doesn't call memdup_user() nor any other
  copy_to_user() function. So, any changes to the properties
  will be lost;

- FE_SET_PROPERTY is declared as a write-only ioctl (IOW).

While we could fix the above, it could cause regressions.

So, let's just assume what the code really does, updating
the documentation accordingly and removing the logic that
would update the discarded tvp->result.

Reviewed-by: Shuah Khan 
Signed-off-by: Mauro Carvalho Chehab 
Signed-off-by: Florian Fainelli 
Signed-off-by: Greg Kroah-Hartman

dt-bindings: display: mediatek: control dpi pins mode to avoid leakage

2020-06-20T08:24:15+00:00

[ Upstream commit b0ff9b590733079f7f9453e5976a9dd2630949e3 ]

Add property "pinctrl-names" to swap pin mode between gpio and dpi mode.
Set the dpi pins to gpio mode and output-low to avoid leakage current
when dpi disabled.

Acked-by: Rob Herring 
Signed-off-by: Jitao Shi 
Signed-off-by: Chun-Kuang Hu 
Signed-off-by: Sasha Levin

x86/kvm/hyper-v: Explicitly align hcall param for kvm_hyperv_exit

2020-06-20T08:24:14+00:00

[ Upstream commit f7d31e65368aeef973fab788aa22c4f1d5a6af66 ]

The problem the patch is trying to address is the fact that 'struct
kvm_hyperv_exit' has different layout on when compiling in 32 and 64 bit
modes.

In 64-bit mode the default alignment boundary is 64 bits thus
forcing extra gaps after 'type' and 'msr' but in 32-bit mode the
boundary is at 32 bits thus no extra gaps.

This is an issue as even when the kernel is 64 bit, the userspace using
the interface can be both 32 and 64 bit but the same 32 bit userspace has
to work with 32 bit kernel.

The issue is fixed by forcing the 64 bit layout, this leads to ABI
change for 32 bit builds and while we are obviously breaking '32 bit
userspace with 32 bit kernel' case, we're fixing the '32 bit userspace
with 64 bit kernel' one.

As the interface has no (known) users and 32 bit KVM is rather baroque
nowadays, this seems like a reasonable decision.

Reviewed-by: Vitaly Kuznetsov 
Signed-off-by: Jon Doron 
Message-Id: <20200424113746.3473563-2-arilou@gmail.com>
Reviewed-by: Roman Kagan 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Sasha Levin

x86/speculation: Add Ivy Bridge to affected list

2020-06-11T07:22:23+00:00

commit 3798cc4d106e91382bfe016caa2edada27c2bb3f upstream

Make the docs match the code.

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

x86/speculation: Add SRBDS vulnerability and mitigation documentation

2020-06-11T07:22:23+00:00

commit 7222a1b5b87417f22265c92deea76a6aecd0fb0f upstream

Add documentation for the SRBDS vulnerability and its mitigation.

 [ bp: Massage.
   jpoimboe: sysfs table strings. ]

Signed-off-by: Mark Gross 
Signed-off-by: Borislav Petkov 
Reviewed-by: Tony Luck 
Reviewed-by: Josh Poimboeuf 
Signed-off-by: Greg Kroah-Hartman

x86/speculation: Add Special Register Buffer Data Sampling (SRBDS) mitigation

2020-06-11T07:22:23+00:00

commit 7e5b3c267d256822407a22fdce6afdf9cd13f9fb upstream

SRBDS is an MDS-like speculative side channel that can leak bits from the
random number generator (RNG) across cores and threads. New microcode
serializes the processor access during the execution of RDRAND and
RDSEED. This ensures that the shared buffer is overwritten before it is
released for reuse.

While it is present on all affected CPU models, the microcode mitigation
is not needed on models that enumerate ARCH_CAPABILITIES[MDS_NO] in the
cases where TSX is not supported or has been disabled with TSX_CTRL.

The mitigation is activated by default on affected processors and it
increases latency for RDRAND and RDSEED instructions. Among other
effects this will reduce throughput from /dev/urandom.

* Enable administrator to configure the mitigation off when desired using
  either mitigations=off or srbds=off.

* Export vulnerability status via sysfs

* Rename file-scoped macros to apply for non-whitelist table initializations.

 [ bp: Massage,
   - s/VULNBL_INTEL_STEPPING/VULNBL_INTEL_STEPPINGS/g,
   - do not read arch cap MSR a second time in tsx_fused_off() - just pass it in,
   - flip check in cpu_set_bug_bits() to save an indentation level,
   - reflow comments.
   jpoimboe: s/Mitigated/Mitigation/ in user-visible strings
   tglx: Dropped the fused off magic for now
 ]

Signed-off-by: Mark Gross 
Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Tony Luck 
Reviewed-by: Pawan Gupta 
Reviewed-by: Josh Poimboeuf 
Tested-by: Neelima Krishnan 
Signed-off-by: Greg Kroah-Hartman

net: l2tp: deprecate PPPOL2TP_MSG_* in favour of L2TP_MSG_*

2020-05-27T14:41:53+00:00

commit 47c3e7783be4e142b861d34b5c2e223330b05d8a upstream.

PPPOL2TP_MSG_* and L2TP_MSG_* are duplicates, and are being used
interchangeably in the kernel, so let's standardize on L2TP_MSG_*
internally, and keep PPPOL2TP_MSG_* defined in UAPI for compatibility.

Signed-off-by: Asbjoern Sloth Toennesen 
Signed-off-by: David S. Miller 
Signed-off-by: Giuliano Procida 
Signed-off-by: Greg Kroah-Hartman

dt-bindings: net: FMan erratum A050385

2020-04-02T15:20:32+00:00

[ Upstream commit 26d5bb9e4c4b541c475751e015072eb2cbf70d15 ]

FMAN DMA read or writes under heavy traffic load may cause FMAN
internal resource leak; thus stopping further packet processing.

The FMAN internal queue can overflow when FMAN splits single
read or write transactions into multiple smaller transactions
such that more than 17 AXI transactions are in flight from FMAN
to interconnect. When the FMAN internal queue overflows, it can
stall further packet processing. The issue can occur with any one
of the following three conditions:

  1. FMAN AXI transaction crosses 4K address boundary (Errata
     A010022)
  2. FMAN DMA address for an AXI transaction is not 16 byte
     aligned, i.e. the last 4 bits of an address are non-zero
  3. Scatter Gather (SG) frames have more than one SG buffer in
     the SG list and any one of the buffers, except the last
     buffer in the SG list has data size that is not a multiple
     of 16 bytes, i.e., other than 16, 32, 48, 64, etc.

With any one of the above three conditions present, there is
likelihood of stalled FMAN packet processing, especially under
stress with multiple ports injecting line-rate traffic.

To avoid situations that stall FMAN packet processing, all of the
above three conditions must be avoided; therefore, configure the
system with the following rules:

  1. Frame buffers must not span a 4KB address boundary, unless
     the frame start address is 256 byte aligned
  2. All FMAN DMA start addresses (for example, BMAN buffer
     address, FD[address] + FD[offset]) are 16B aligned
  3. SG table and buffer addresses are 16B aligned and the size
     of SG buffers are multiple of 16 bytes, except for the last
     SG buffer that can be of any size.

Additional workaround notes:
- Address alignment of 64 bytes is recommended for maximally
efficient system bus transactions (although 16 byte alignment is
sufficient to avoid the stall condition)
- To support frame sizes that are larger than 4K bytes, there are
two options:
  1. Large single buffer frames that span a 4KB page boundary can
     be converted into SG frames to avoid transaction splits at
     the 4KB boundary,
  2. Align the large single buffer to 256B address boundaries,
     ensure that the frame address plus offset is 256B aligned.
- If software generated SG frames have buffers that are unaligned
and with random non-multiple of 16 byte lengths, before
transmitting such frames via FMAN, frames will need to be copied
into a new single buffer or multiple buffer SG frame that is
compliant with the three rules listed above.

Signed-off-by: Madalin Bucur 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

ACPI: watchdog: Allow disabling WDAT at boot

2020-03-20T08:07:56+00:00

[ Upstream commit 3f9e12e0df012c4a9a7fd7eb0d3ae69b459d6b2c ]

In case the WDAT interface is broken, give the user an option to
ignore it to let a native driver bind to the watchdog device instead.

Signed-off-by: Jean Delvare 
Acked-by: Mika Westerberg 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

cifs_atomic_open(): fix double-put on late allocation failure

2020-03-20T08:07:44+00:00

commit d9a9f4849fe0c9d560851ab22a85a666cddfdd24 upstream.

several iterations of ->atomic_open() calling conventions ago, we
used to need fput() if ->atomic_open() failed at some point after
successful finish_open().  Now (since 2016) it's not needed -
struct file carries enough state to make fput() work regardless
of the point in struct file lifecycle and discarding it on
failure exits in open() got unified.  Unfortunately, I'd missed
the fact that we had an instance of ->atomic_open() (cifs one)
that used to need that fput(), as well as the stale comment in
finish_open() demanding such late failure handling.  Trivially
fixed...

Fixes: fe9ec8291fca "do_last(): take fput() on error after opening to out:"
Cc: stable@kernel.org # v4.7+
Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman