Increase rng-seed size to make Linux happy and initialize rng pool instantly. Linux 5.19+ requires 32 bytes of entropy to initialize random pool, but u-boot currently provides only 8 bytes. Linux 5.18 and probably some vesrions before it used to require 64 bytes. Bump min value to 64 bytes to be on a safe side.
Boot with 8 byte rng-seed (Linux 6.11): # dmesg | grep crng [ 12.089286] random: crng init done Boot with 32 byte rng-seed (Linux 6.11): # dmesg | grep crng [ 0.000000] random: crng init done
Linux source references: https://github.com/torvalds/linux/blob/7234e2ea0edd00bfb6bb2159e55878c19885c... https://elixir.bootlin.com/linux/v5.18/source/drivers/char/random.c#L236 https://elixir.bootlin.com/linux/v5.19/source/drivers/char/random.c#L551
Signed-off-by: Alex Shumsky alexthreed@gmail.com Fixes: d2048bafae40 ("rockchip: board: Add board_rng_seed() for all Rockchip devices") ---
Changes in v3: - reword warning - increase default rng_seed_size to support older linux as well - reword commit message
Changes in v2: - add env config knob rng_seed_size - add warning for small rng_seed_size - 12-character commit SHA in Fixes
arch/arm/mach-rockchip/board.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/arm/mach-rockchip/board.c b/arch/arm/mach-rockchip/board.c index 3fadf7e412..9ff1567fb1 100644 --- a/arch/arm/mach-rockchip/board.c +++ b/arch/arm/mach-rockchip/board.c @@ -472,9 +472,16 @@ __weak int misc_init_r(void) __weak int board_rng_seed(struct abuf *buf) { struct udevice *dev; - size_t len = 0x8; + ulong len = env_get_ulong("rng_seed_size", 10, 64); u64 *data;
+ if (len < 64) { + // rng_seed_size should be at least 32 bytes for Linux 5.19+, or 64 for + // older Linux'es + log_warning("Value for rng_seed_size too low (%lu) and likely insufficient for the Linux RNG initialization\n", + len); + } + data = malloc(len); if (!data) { printf("Out of memory\n");