linux-stable.git/Documentation, branch v5.4.73

x86/fpu: Allow multiple bits in clearcpuid= parameter

2020-10-29T08:57:29+00:00

[ Upstream commit 0a4bb5e5507a585532cc413125b921c8546fc39f ]

Commit

  0c2a3913d6f5 ("x86/fpu: Parse clearcpuid= as early XSAVE argument")

changed clearcpuid parsing from __setup() to cmdline_find_option().
While the __setup() function would have been called for each clearcpuid=
parameter on the command line, cmdline_find_option() will only return
the last one, so the change effectively made it impossible to disable
more than one bit.

Allow a comma-separated list of bit numbers as the argument for
clearcpuid to allow multiple bits to be disabled again. Log the bits
being disabled for informational purposes.

Also fix the check on the return value of cmdline_find_option(). It
returns -1 when the option is not found, so testing as a boolean is
incorrect.

Fixes: 0c2a3913d6f5 ("x86/fpu: Parse clearcpuid= as early XSAVE argument")
Signed-off-by: Arvind Sankar 
Signed-off-by: Borislav Petkov 
Link: https://lkml.kernel.org/r/20200907213919.2423441-1-nivedita@alum.mit.edu
Signed-off-by: Sasha Levin

icmp: randomize the global rate limiter

2020-10-29T08:57:27+00:00

[ Upstream commit b38e7819cae946e2edf869e604af1e65a5d241c5 ]

Keyu Man reported that the ICMP rate limiter could be used
by attackers to get useful signal. Details will be provided
in an upcoming academic publication.

Our solution is to add some noise, so that the attackers
no longer can get help from the predictable token bucket limiter.

Fixes: 4cdf507d5452 ("icmp: add a global rate limitation")
Signed-off-by: Eric Dumazet 
Reported-by: Keyu Man 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

block/diskstats: more accurate approximation of io_ticks for slow disks

2020-10-07T06:01:29+00:00

commit 2b8bd423614c595540eaadcfbc702afe8e155e50 upstream.

Currently io_ticks is approximated by adding one at each start and end of
requests if jiffies counter has changed. This works perfectly for requests
shorter than a jiffy or if one of requests starts/ends at each jiffy.

If disk executes just one request at a time and they are longer than two
jiffies then only first and last jiffies will be accounted.

Fix is simple: at the end of request add up into io_ticks jiffies passed
since last update rather than just one jiffy.

Example: common HDD executes random read 4k requests around 12ms.

fio --name=test --filename=/dev/sdb --rw=randread --direct=1 --runtime=30 &
iostat -x 10 sdb

Note changes of iostat's "%util" 8,43% -> 99,99% before/after patch:

Before:

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
sdb               0,00     0,00   82,60    0,00   330,40     0,00     8,00     0,96   12,09   12,09    0,00   1,02   8,43

After:

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
sdb               0,00     0,00   82,50    0,00   330,00     0,00     8,00     1,00   12,10   12,10    0,00  12,12  99,99

Now io_ticks does not loose time between start and end of requests, but
for queue-depth > 1 some I/O time between adjacent starts might be lost.

For load estimation "%util" is not as useful as average queue length,
but it clearly shows how often disk queue is completely empty.

Fixes: 5b18b5a73760 ("block: delete part_round_stats and switch to less precise counting")
Signed-off-by: Konstantin Khlebnikov 
Reviewed-by: Ming Lei 
Signed-off-by: Jens Axboe 
From: "Banerjee, Debabrata" 
Signed-off-by: Greg Kroah-Hartman

gpio/aspeed-sgpio: enable access to all 80 input & output sgpios

2020-10-07T06:01:28+00:00

[ Upstream commit ac67b07e268d46eba675a60c37051bb3e59fd201 ]

Currently, the aspeed-sgpio driver exposes up to 80 GPIO lines,
corresponding to the 80 status bits available in hardware. Each of these
lines can be configured as either an input or an output.

However, each of these GPIOs is actually an input *and* an output; we
actually have 80 inputs plus 80 outputs.

This change expands the maximum number of GPIOs to 160; the lower half
of this range are the input-only GPIOs, the upper half are the outputs.
We fix the GPIO directions to correspond to this mapping.

This also fixes a bug when setting GPIOs - we were reading from the
input register, making it impossible to set more than one output GPIO.

Signed-off-by: Jeremy Kerr 
Fixes: 7db47faae79b ("gpio: aspeed: Add SGPIO driver")
Reviewed-by: Joel Stanley 
Reviewed-by: Andrew Jeffery 
Acked-by: Rob Herring 
Signed-off-by: Bartosz Golaszewski 
Signed-off-by: Sasha Levin

ata: make qc_prep return ata_completion_errors

2020-10-01T11:18:26+00:00

commit 95364f36701e62dd50eee91e1303187fd1a9f567 upstream.

In case a driver wants to return an error from qc_prep, return enum
ata_completion_errors. sata_mv is one of those drivers -- see the next
patch. Other drivers return the newly defined AC_ERR_OK.

[v2] use enum ata_completion_errors and AC_ERR_OK.

Signed-off-by: Jiri Slaby 
Cc: Jens Axboe 
Cc: linux-ide@vger.kernel.org
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

dt-bindings: sound: wm8994: Correct required supplies based on actual implementaion

2020-10-01T11:17:58+00:00

[ Upstream commit 8c149b7d75e53be47648742f40fc90d9fc6fa63a ]

The required supplies in bindings were actually not matching
implementation making the bindings incorrect and misleading.  The Linux
kernel driver requires all supplies to be present.  Also for wlf,wm8994
uses just DBVDD-supply instead of DBVDDn-supply (n: <1,3>).

Reported-by: Jonathan Bakker 
Signed-off-by: Krzysztof Kozlowski 
Link: https://lore.kernel.org/r/20200501133534.6706-1-krzk@kernel.org
Signed-off-by: Mark Brown 
Signed-off-by: Sasha Levin

affs: fix basic permission bits to actually work

2020-09-09T17:12:34+00:00

commit d3a84a8d0dde4e26bc084b36ffcbdc5932ac85e2 upstream.

The basic permission bits (protection bits in AmigaOS) have been broken
in Linux' AFFS - it would only set bits, but never delete them.
Also, contrary to the documentation, the Archived bit was not handled.

Let's fix this for good, and set the bits such that Linux and classic
AmigaOS can coexist in the most peaceful manner.

Also, update the documentation to represent the current state of things.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Max Staudt 
Signed-off-by: David Sterba 
Signed-off-by: Greg Kroah-Hartman

mmc: dt-bindings: Add resets/reset-names for Mediatek MMC bindings

2020-09-09T17:12:33+00:00

commit 65557383191de46611dd3d6b639cbcfbade43c4a upstream.

Add description for resets/reset-names.

Cc:  # v5.4+
Fixes: 966580ad236e ("mmc: mediatek: add support for MT7622 SoC")
Signed-off-by: Wenbin Mei 
Tested-by: Frank Wunderlich 
Link: https://lore.kernel.org/r/20200814014346.6496-2-wenbin.mei@mediatek.com
Signed-off-by: Ulf Hansson 
Signed-off-by: Greg Kroah-Hartman

dt-bindings: mmc: tegra: Add tmclk for Tegra210 and later

2020-09-05T09:22:50+00:00

commit f7f86e8ac0ad7cd6792a80137f5a550924966916 upstream.

commit b5a84ecf025a ("mmc: tegra: Add Tegra210 support")

Tegra210 and later uses separate SDMMC_LEGACY_TM clock for data
timeout.

So, this patch adds "tmclk" to Tegra sdhci clock property in the
device tree binding.

Fixes: b5a84ecf025a ("mmc: tegra: Add Tegra210 support")
Cc: stable  # 5.4
Reviewed-by: Jon Hunter 
Signed-off-by: Sowjanya Komatineni 
Link: https://lore.kernel.org/r/1598548861-32373-4-git-send-email-skomatineni@nvidia.com
Signed-off-by: Ulf Hansson 
Signed-off-by: Greg Kroah-Hartman

kbuild: support LLVM=1 to switch the default tools to Clang/LLVM

2020-08-26T08:40:47+00:00

commit a0d1c951ef08ed24f35129267e3595d86f57f5d3 upstream.

As Documentation/kbuild/llvm.rst implies, building the kernel with a
full set of LLVM tools gets very verbose and unwieldy.

Provide a single switch LLVM=1 to use Clang and LLVM tools instead
of GCC and Binutils. You can pass it from the command line or as an
environment variable.

Please note LLVM=1 does not turn on the integrated assembler. You need
to pass LLVM_IAS=1 to use it. When the upstream kernel is ready for the
integrated assembler, I think we can make it default.

We discussed what we need, and we agreed to go with a simple boolean
flag that switches both target and host tools:

  https://lkml.org/lkml/2020/3/28/494
  https://lkml.org/lkml/2020/4/3/43

Some items discussed, but not adopted:

- LLVM_DIR

  When multiple versions of LLVM are installed, I just thought supporting
  LLVM_DIR=/path/to/my/llvm/bin/ might be useful.

  CC      = $(LLVM_DIR)clang
  LD      = $(LLVM_DIR)ld.lld
    ...

  However, we can handle this by modifying PATH. So, we decided to not do
  this.

- LLVM_SUFFIX

  Some distributions (e.g. Debian) package specific versions of LLVM with
  naming conventions that use the version as a suffix.

  CC      = clang$(LLVM_SUFFIX)
  LD      = ld.lld(LLVM_SUFFIX)
    ...

  will allow a user to pass LLVM_SUFFIX=-11 to use clang-11 etc.,
  but the suffixed versions in /usr/bin/ are symlinks to binaries in
  /usr/lib/llvm-#/bin/, so this can also be handled by PATH.

Signed-off-by: Masahiro Yamada 
Reviewed-by: Nathan Chancellor 
Tested-by: Nathan Chancellor  # build
Tested-by: Nick Desaulniers 
Reviewed-by: Nick Desaulniers 
Signed-off-by: Nick Desaulniers 
Signed-off-by: Greg Kroah-Hartman