linux-stable.git/Documentation, branch v5.4.201

Revert "hwmon: Make chip parameter for with_info API mandatory"

2022-06-25T10:44:36+00:00

This reverts commit 1ec0bc72f5dab3ab367ae5230cf6f212d805a225 which is
commit ddaefa209c4ac791c1262e97c9b2d0440c8ef1d5 upstream.  It should not
have been applied to the stable trees.

Link: https://lore.kernel.org/r/20220622154454.GA1864037@roeck-us.net
Reported-by: Julian Haller 
Reported-by: Guenter Roeck 
Cc: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

random: fix sysctl documentation nits

2022-06-22T12:11:14+00:00

commit 069c4ea6871c18bd368f27756e0f91ffb524a788 upstream.

A semicolon was missing, and the almost-alphabetical-but-not ordering
was confusing, so regroup these by category instead.

Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Greg Kroah-Hartman

random: treat bootloader trust toggle the same way as cpu trust toggle

2022-06-22T12:11:13+00:00

commit d97c68d178fbf8aaaf21b69b446f2dfb13909316 upstream.

If CONFIG_RANDOM_TRUST_CPU is set, the RNG initializes using RDRAND.
But, the user can disable (or enable) this behavior by setting
`random.trust_cpu=0/1` on the kernel command line. This allows system
builders to do reasonable things while avoiding howls from tinfoil
hatters. (Or vice versa.)

CONFIG_RANDOM_TRUST_BOOTLOADER is basically the same thing, but regards
the seed passed via EFI or device tree, which might come from RDRAND or
a TPM or somewhere else. In order to allow distros to more easily enable
this while avoiding those same howls (or vice versa), this commit adds
the corresponding `random.trust_bootloader=0/1` toggle.

Cc: Theodore Ts'o 
Cc: Graham Christensen 
Reviewed-by: Ard Biesheuvel 
Reviewed-by: Dominik Brodowski 
Link: https://github.com/NixOS/nixpkgs/pull/165355
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Greg Kroah-Hartman

random: remove ifdef'd out interrupt bench

2022-06-22T12:11:10+00:00

commit 95e6060c20a7f5db60163274c5222a725ac118f9 upstream.

With tools like kbench9000 giving more finegrained responses, and this
basically never having been used ever since it was initially added,
let's just get rid of this. There *is* still work to be done on the
interrupt handler, but this really isn't the way it's being developed.

Cc: Theodore Ts'o 
Reviewed-by: Eric Biggers 
Reviewed-by: Dominik Brodowski 
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Greg Kroah-Hartman

random: always wake up entropy writers after extraction

2022-06-22T12:11:08+00:00

commit 489c7fc44b5740d377e8cfdbf0851036e493af00 upstream.

Now that POOL_BITS == POOL_MIN_BITS, we must unconditionally wake up
entropy writers after every extraction. Therefore there's no point of
write_wakeup_threshold, so we can move it to the dustbin of unused
compatibility sysctls. While we're at it, we can fix a small comparison
where we were waking up after <= min rather than < min.

Cc: Theodore Ts'o 
Suggested-by: Eric Biggers 
Reviewed-by: Eric Biggers 
Reviewed-by: Dominik Brodowski 
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Greg Kroah-Hartman

x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data

2022-06-16T11:23:32+00:00

commit 8d50cdf8b8341770bc6367bce40c0c1bb0e1d5b3 upstream

Add the sysfs reporting file for Processor MMIO Stale Data
vulnerability. It exposes the vulnerability and mitigation state similar
to the existing files for the other hardware vulnerabilities.

Signed-off-by: Pawan Gupta 
Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

x86/speculation/mmio: Add mitigation for Processor MMIO Stale Data

2022-06-16T11:23:31+00:00

commit 8cb861e9e3c9a55099ad3d08e1a3b653d29c33ca upstream

Processor MMIO Stale Data is a class of vulnerabilities that may
expose data after an MMIO operation. For details please refer to
Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst.

These vulnerabilities are broadly categorized as:

Device Register Partial Write (DRPW):
  Some endpoint MMIO registers incorrectly handle writes that are
  smaller than the register size. Instead of aborting the write or only
  copying the correct subset of bytes (for example, 2 bytes for a 2-byte
  write), more bytes than specified by the write transaction may be
  written to the register. On some processors, this may expose stale
  data from the fill buffers of the core that created the write
  transaction.

Shared Buffers Data Sampling (SBDS):
  After propagators may have moved data around the uncore and copied
  stale data into client core fill buffers, processors affected by MFBDS
  can leak data from the fill buffer.

Shared Buffers Data Read (SBDR):
  It is similar to Shared Buffer Data Sampling (SBDS) except that the
  data is directly read into the architectural software-visible state.

An attacker can use these vulnerabilities to extract data from CPU fill
buffers using MDS and TAA methods. Mitigate it by clearing the CPU fill
buffers using the VERW instruction before returning to a user or a
guest.

On CPUs not affected by MDS and TAA, user application cannot sample data
from CPU fill buffers using MDS or TAA. A guest with MMIO access can
still use DRPW or SBDR to extract data architecturally. Mitigate it with
VERW instruction to clear fill buffers before VMENTER for MMIO capable
guests.

Add a kernel parameter mmio_stale_data={off|full|full,nosmt} to control
the mitigation.

Signed-off-by: Pawan Gupta 
Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

Documentation: Add documentation for Processor MMIO Stale Data

2022-06-16T11:23:31+00:00

commit 4419470191386456e0b8ed4eb06a70b0021798a6 upstream

Add the admin guide for Processor MMIO stale data vulnerabilities.

Signed-off-by: Pawan Gupta 
Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

ata: libata-transport: fix {dma|pio|xfer}_mode sysfs files

2022-06-14T16:12:02+00:00

commit 72aad489f992871e908ff6d9055b26c6366fb864 upstream.

The {dma|pio}_mode sysfs files are incorrectly documented as having a
list of the supported DMA/PIO transfer modes, while the corresponding
fields of the *struct* ata_device hold the transfer mode IDs, not masks.

To match these docs, the {dma|pio}_mode (and even xfer_mode!) sysfs
files are handled by the ata_bitfield_name_match() macro which leads to
reading such kind of nonsense from them:

$ cat /sys/class/ata_device/dev3.0/pio_mode
XFER_UDMA_7, XFER_UDMA_6, XFER_UDMA_5, XFER_UDMA_4, XFER_MW_DMA_4,
XFER_PIO_6, XFER_PIO_5, XFER_PIO_4, XFER_PIO_3, XFER_PIO_2, XFER_PIO_1,
XFER_PIO_0

Using the correct ata_bitfield_name_search() macro fixes that:

$ cat /sys/class/ata_device/dev3.0/pio_mode
XFER_PIO_4

While fixing the file documentation, somewhat reword the {dma|pio}_mode
file doc and add a note about being mostly useful for PATA devices to
the xfer_mode file doc...

Fixes: d9027470b886 ("[libata] Add ATA transport class")
Signed-off-by: Sergey Shtylyov 
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal 
Signed-off-by: Greg Kroah-Hartman

dt-bindings: gpio: altera: correct interrupt-cells

2022-06-14T16:11:49+00:00

commit 3a21c3ac93aff7b4522b152399df8f6a041df56d upstream.

update documentation to correctly state the interrupt-cells to be 2.

Cc: stable@vger.kernel.org
Fixes: 4fd9bbc6e071 ("drivers/gpio: Altera soft IP GPIO driver devicetree binding")
Signed-off-by: Dinh Nguyen 
Signed-off-by: Greg Kroah-Hartman