linux-stable.git/Documentation, branch v5.1.7

dt-bindings: phy-qcom-qmp: Add UFS PHY reset

2019-05-31T13:43:31+00:00

[ Upstream commit 95cee0b4e30a09a411a17e9a3bc6b72ed92063da ]

Add a required reset to the SDM845 UFS phy to express the PHY reset
bit inside the UFS controller register space. Before this change, this
reset was not expressed in the DT, and the driver utilized two different
callbacks (phy_init and phy_poweron) to implement a two-phase
initialization procedure that involved deasserting this reset between
init and poweron. This abused the two callbacks and diluted their
purpose.

That scheme does not work as regulators cannot be turned off in
phy_poweroff because they were turned on in init, rather than poweron.
The net result is that regulators are left on in suspend that shouldn't
be.

This new scheme gives the UFS reset to the PHY, so that it can fully
initialize itself in a single callback. We can then turn regulators on
during poweron and off during poweroff.

Signed-off-by: Evan Green 
Reviewed-by: Rob Herring 
Reviewed-by: Stephen Boyd 
Signed-off-by: Kishon Vijay Abraham I 
Signed-off-by: Sasha Levin

arm64: errata: Add workaround for Cortex-A76 erratum #1463225

2019-05-31T13:43:11+00:00

commit 969f5ea627570e91c9d54403287ee3ed657f58fe upstream.

Revisions of the Cortex-A76 CPU prior to r4p0 are affected by an erratum
that can prevent interrupts from being taken when single-stepping.

This patch implements a software workaround to prevent userspace from
effectively being able to disable interrupts.

Cc: 
Cc: Marc Zyngier 
Cc: Catalin Marinas 
Signed-off-by: Will Deacon 
Signed-off-by: Greg Kroah-Hartman

dcache: sort the freeing-without-RCU-delay mess for good.

2019-05-25T16:16:24+00:00

commit 5467a68cbf6884c9a9d91e2a89140afb1839c835 upstream.

For lockless accesses to dentries we don't have pinned we rely
(among other things) upon having an RCU delay between dropping
the last reference and actually freeing the memory.

On the other hand, for things like pipes and sockets we neither
do that kind of lockless access, nor want to deal with the
overhead of an RCU delay every time a socket gets closed.

So delay was made optional - setting DCACHE_RCUACCESS in ->d_flags
made sure it would happen.  We tried to avoid setting it unless
we knew we need it.  Unfortunately, that had led to recurring
class of bugs, in which we missed the need to set it.

We only really need it for dentries that are created by
d_alloc_pseudo(), so let's not bother with trying to be smart -
just make having an RCU delay the default.  The ones that do
*not* get it set the replacement flag (DCACHE_NORCU) and we'd
better use that sparingly.  d_alloc_pseudo() is the only
such user right now.

FWIW, the race that finally prompted that switch had been
between __lock_parent() of immediate subdirectory of what's
currently the root of a disconnected tree (e.g. from
open-by-handle in progress) racing with d_splice_alias()
elsewhere picking another alias for the same inode, either
on outright corrupted fs image, or (in case of open-by-handle
on NFS) that subdirectory having been just moved on server.
It's not easy to hit, so the sky is not falling, but that's
not the first race on similar missed cases and the logics
for settinf DCACHE_RCUACCESS has gotten ridiculously
convoluted.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

dt-bindings: mmc: Add disable-cqe-dcmd property.

2019-05-22T05:39:46+00:00

commit 28f22fb755ecf9f933f045bc0afdb8140641b01c upstream.

Add disable-cqe-dcmd as optional property for MMC hosts.
This property allows to disable or not enable the direct command
features of the command queue engine.

Signed-off-by: Christoph Muellner 
Signed-off-by: Philipp Tomsich 
Fixes: 84362d79f436 ("mmc: sdhci-of-arasan: Add CQHCI support for arasan,sdhci-5.1")
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson 
Signed-off-by: Greg Kroah-Hartman

x86/speculation/mds: Improve CPU buffer clear documentation

2019-05-22T05:39:39+00:00

commit 9d8d0294e78a164d407133dea05caf4b84247d6a upstream.

On x86_64, all returns to usermode go through
prepare_exit_to_usermode(), with the sole exception of do_nmi().
This even includes machine checks -- this was added several years
ago to support MCE recovery.  Update the documentation.

Signed-off-by: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Frederic Weisbecker 
Cc: Greg Kroah-Hartman 
Cc: Jon Masters 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: stable@vger.kernel.org
Fixes: 04dcbdb80578 ("x86/speculation/mds: Clear CPU buffers on exit to user")
Link: http://lkml.kernel.org/r/999fa9e126ba6a48e9d214d2f18dbde5c62ac55c.1557865329.git.luto@kernel.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86/speculation/mds: Revert CPU buffer clear on double fault exit

2019-05-22T05:39:39+00:00

commit 88640e1dcd089879530a49a8d212d1814678dfe7 upstream.

The double fault ESPFIX path doesn't return to user mode at all --
it returns back to the kernel by simulating a #GP fault.
prepare_exit_to_usermode() will run on the way out of
general_protection before running user code.

Signed-off-by: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Frederic Weisbecker 
Cc: Greg Kroah-Hartman 
Cc: Jon Masters 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: stable@vger.kernel.org
Fixes: 04dcbdb80578 ("x86/speculation/mds: Clear CPU buffers on exit to user")
Link: http://lkml.kernel.org/r/ac97612445c0a44ee10374f6ea79c222fe22a5c4.1557865329.git.luto@kernel.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86/speculation/mds: Fix documentation typo

2019-05-14T17:15:32+00:00

commit 95310e348a321b45fb746c176961d4da72344282 upstream

Fix a minor typo in the MDS documentation: "eanbled" -> "enabled".

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

Documentation: Correct the possible MDS sysfs values

2019-05-14T17:15:32+00:00

commit ea01668f9f43021b28b3f4d5ffad50106a1e1301 upstream

Adjust the last two rows in the table that display possible values when
MDS mitigation is enabled. They both were slightly innacurate.

In addition, convert the table of possible values and their descriptions
to a list-table. The simple table format uses the top border of equals
signs to determine cell width which resulted in the first column being
far too wide in comparison to the second column that contained the
majority of the text.

Signed-off-by: Tyler Hicks 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

x86/mds: Add MDSUM variant to the MDS documentation

2019-05-14T17:15:32+00:00

commit e672f8bf71c66253197e503f75c771dd28ada4a0 upstream

Updated the documentation for a new CVE-2019-11091 Microarchitectural Data
Sampling Uncacheable Memory (MDSUM) which is a variant of
Microarchitectural Data Sampling (MDS). MDS is a family of side channel
attacks on internal buffers in Intel CPUs.

MDSUM is a special case of MSBDS, MFBDS and MLPDS. An uncacheable load from
memory that takes a fault or assist can leave data in a microarchitectural
structure that may later be observed using one of the same methods used by
MSBDS, MFBDS or MLPDS. There are no new code changes expected for MDSUM.
The existing mitigation for MDS applies to MDSUM as well.

Signed-off-by: Pawan Gupta 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Tyler Hicks 
Reviewed-by: Jon Masters 
Signed-off-by: Greg Kroah-Hartman

x86/speculation/mds: Add 'mitigations=' support for MDS

2019-05-14T17:15:32+00:00

commit 5c14068f87d04adc73ba3f41c2a303d3c3d1fa12 upstream

Add MDS to the new 'mitigations=' cmdline option.

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