Re: [PATCH v9 2/3] fdt: add support for rng-seed

Theodore Y. Ts'o
2019-08-22T16:06:30Z

On Thu, Aug 22, 2019 at 03:15:22PM +0800, Hsin-Yi Wang wrote:
> Introducing a chosen node, rng-seed, which is an entropy that can be
> passed to kernel called very early to increase initial device
> randomness. Bootloader should provide this entropy and the value is
> read from /chosen/rng-seed in DT.
>
> Obtain of_fdt_crc32 for CRC check after early_init_dt_scan_nodes(),
> since early_init_dt_scan_chosen() would modify fdt to erase rng-seed.
>
> Add a new interface add_bootloader_randomness() for rng-seed use case.
> Depends on whether the seed is trustworthy, rng seed would be passed to
> add_hwgenerator_randomness(). Otherwise it would be passed to
> add_device_randomness(). Decision is controlled by kernel config
> RANDOM_TRUST_BOOTLOADER.
>
> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
> Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> Reviewed-by: Rob Herring <robh@kernel.org>

For the changes to drivers/char/random.c:

Reviewed-by: Theodore Ts'o <tytso@mit.edu>