Hi Alex,
On 10/15/24 12:15 AM, Alex Shumsky wrote:
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 versions 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://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/char/random.c?h=v5.19#n551
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/char/random.c?h=v5.18#n236
Signed-off-by: Alex Shumsky <alexthr...@gmail.com>
Fixes: d2048bafae40 ("rockchip: board: Add board_rng_seed() for all Rockchip
devices")
Reviewed-by: Dragan Simic <dsi...@manjaro.org>
---
Changes in v4:
- fix typos and code style
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 | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/arch/arm/mach-rockchip/board.c b/arch/arm/mach-rockchip/board.c
index 3fadf7e412..ca6404776f 100644
--- a/arch/arm/mach-rockchip/board.c
+++ b/arch/arm/mach-rockchip/board.c
@@ -472,9 +472,18 @@ __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);
I'm wondering if we have somewhere some documentation on the environment
variables that exist and what they used for because this would be a nice
addition. At the very least, we can mention this variable in:
- include/fdt_support.h for the function
- common/Kconfig for the symbol
I'm also a bit torn on the base though, I think the assumed base is
generally hex and not dec, so maybe we should rather have that?
Looking good otherwise :)
Cheers,
Quentin
