fdt: add support for rng-seed
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> Reviewed-by: Theodore Ts'o <tytso@mit.edu> # drivers/char/random.c Signed-off-by:
Will Deacon <will@kernel.org>
parent
e112b032
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