linux-stable.git/drivers/char/hw_random, branch v5.4.4

hwrng: omap - Fix RNG wait loop timeout

2019-12-17T18:56:11+00:00

commit be867f987a4e1222114dd07a01838a17c26f3fff upstream.

Existing RNG data read timeout is 200us but it doesn't cover EIP76 RNG
data rate which takes approx. 700us to produce 16 bytes of output data
as per testing results. So configure the timeout as 1000us to also take
account of lack of udelay()'s reliability.

Fixes: 383212425c92 ("hwrng: omap - Add device variant for SafeXcel IP-76 found in Armada 8K")
Cc: 
Signed-off-by: Sumit Garg 
Signed-off-by: Herbert Xu 
Signed-off-by: Greg Kroah-Hartman

Revert "hwrng: core - Freeze khwrng thread during suspend"

2019-11-17T00:48:17+00:00

This reverts commit 03a3bb7ae631 ("hwrng: core - Freeze khwrng
thread during suspend"), ff296293b353 ("random: Support freezable
kthreads in add_hwgenerator_randomness()") and 59b569480dc8 ("random:
Use wait_event_freezable() in add_hwgenerator_randomness()").

These patches introduced regressions and we need more time to
get them ready for mainline.

Signed-off-by: Herbert Xu

hwrng: core - don't wait on add_early_randomness()

2019-09-20T13:05:33+00:00

add_early_randomness() is called by hwrng_register() when the
hardware is added. If this hardware and its module are present
at boot, and if there is no data available the boot hangs until
data are available and can't be interrupted.

For instance, in the case of virtio-rng, in some cases the host can be
not able to provide enough entropy for all the guests.

We can have two easy ways to reproduce the problem but they rely on
misconfiguration of the hypervisor or the egd daemon:

- if virtio-rng device is configured to connect to the egd daemon of the
host but when the virtio-rng driver asks for data the daemon is not
connected,

- if virtio-rng device is configured to connect to the egd daemon of the
host but the egd daemon doesn't provide data.

The guest kernel will hang at boot until the virtio-rng driver provides
enough data.

To avoid that, call rng_get_data() in non-blocking mode (wait=0)
from add_early_randomness().

Signed-off-by: Laurent Vivier 
Fixes: d9e797261933 ("hwrng: add randomness to system from rng...")
Cc: 
Reviewed-by: Theodore Ts'o 
Signed-off-by: Herbert Xu

hwrng: timeriomem - relax check on memory resource size

2019-09-05T04:37:30+00:00

The timeriomem_rng driver only accesses the first 4 bytes of the given
memory area and currently, it also forces that memory resource to be
exactly 4 bytes in size.

This, however, is problematic when used with device-trees that are
generated from things like FPGA toolchains, where the minimum size
of an exposed memory block may be something like 4k.

Hence, let's only check for what's needed for the driver to operate
properly; namely that we have enough memory available to read the
random data from.

Signed-off-by: Daniel Mack 
Signed-off-by: Herbert Xu

hwrng: core - Freeze khwrng thread during suspend

2019-08-15T11:52:13+00:00

The hwrng_fill() function can run while devices are suspending and
resuming. If the hwrng is behind a bus such as i2c or SPI and that bus
is suspended, the hwrng may hang the bus while attempting to add some
randomness. It's been observed on ChromeOS devices with suspend-to-idle
(s2idle) and an i2c based hwrng that this kthread may run and ask the
hwrng device for randomness before the i2c bus has been resumed.

Let's make this kthread freezable so that we don't try to touch the
hwrng during suspend/resume. This ensures that we can't cause the hwrng
backing driver to get into a bad state because the device is guaranteed
to be resumed before the hwrng kthread is thawed.

Cc: Andrey Pronin 
Cc: Duncan Laurie 
Cc: Jason Gunthorpe 
Cc: Arnd Bergmann 
Cc: Greg Kroah-Hartman 
Cc: Guenter Roeck 
Cc: Alexander Steffen 
Signed-off-by: Stephen Boyd 
Signed-off-by: Herbert Xu

hwrng: n2-drv - fix typo

2019-08-08T02:07:49+00:00

Fixes: 3e75241be808 ("hwrng: drivers - Use device-managed registration API")
Signed-off-by: Stephen Rothwell 
Signed-off-by: Herbert Xu

hwrng: drivers - Use device-managed registration API

2019-08-02T04:44:33+00:00

Use devm_hwrng_register to simplify the implementation.
Manual unregistration and some remove functions can be
removed now.

Signed-off-by: Chuhong Yuan 
Acked-by: Łukasz Stelmach 
Acked-by: Ludovic Desroches 
Signed-off-by: Herbert Xu

hwrng: mxc-rnga - use devm_platform_ioremap_resource() to simplify code

2019-07-27T11:08:32+00:00

Use the new helper devm_platform_ioremap_resource() which wraps the
platform_get_resource() and devm_ioremap_resource() together, to
simplify the code.

Signed-off-by: Anson Huang 
Reviewed-by: Dong Aisheng 
Signed-off-by: Herbert Xu

hwrng: imx-rngc - use devm_platform_ioremap_resource() to simplify code

2019-07-27T11:08:32+00:00

Use the new helper devm_platform_ioremap_resource() which wraps the
platform_get_resource() and devm_ioremap_resource() together, to
simplify the code.

Signed-off-by: Anson Huang 
Acked-by: Arnd Bergmann 
Reviewed-by: Dong Aisheng 
Signed-off-by: Herbert Xu

docs: admin-guide: add a series of orphaned documents

2019-07-15T14:03:02+00:00

There are lots of documents that belong to the admin-guide but
are on random places (most under Documentation root dir).

Move them to the admin guide.

Signed-off-by: Mauro Carvalho Chehab 
Acked-by: Alexandre Belloni 
Acked-by: Bartlomiej Zolnierkiewicz