On 1/31/2018 4:00 AM, Bryan O'Donoghue wrote:
> commit 1005bccd7a4a ("crypto: caam - enable instantiation of all RNG4 state
> handles") introduces a control when incrementing ent_delay which contains
> the following comment above it:
>
> /*
> * If either SH were instantiated by somebody else
> * (e.g. u-boot) then it is assumed that the entropy
> * parameters are properly set and thus the function
> * setting these (kick_trng(...)) is skipped.
> * Also, if a handle was instantiated, do not change
> * the TRNG parameters.
> */
>
> This is a problem observed when sec_init() has been run in u-boot and
> and TrustZone is enabled. We can fix this by instantiating all rng state
> handles in u-boot but, on the Kernel side we should ensure that this
> non-terminating path is dealt with.
>
> Fixes: 1005bccd7a4a ("crypto: caam - enable instantiation of all RNG4 state
> handles")
>
> Reported-by: Ryan Harkin <ryan.harkin@xxxxxxxxxx>
> Cc: "Horia Geantă" <horia.geanta@xxxxxxx>
> Cc: Aymen Sghaier <aymen.sghaier@xxxxxxx>
> Cc: Fabio Estevam <fabio.estevam@xxxxxxx>
> Cc: Peng Fan <peng.fan@xxxxxxx>
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> Cc: Lukas Auer <lukas.auer@xxxxxxxxxxxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> # 4.12+
> Signed-off-by: Bryan O'Donoghue <pure.logic@xxxxxxxxxxxxxxxxx>
> ---
> drivers/crypto/caam/ctrl.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c
> index 98986d3..0a1e96b 100644
> --- a/drivers/crypto/caam/ctrl.c
> +++ b/drivers/crypto/caam/ctrl.c
> @@ -704,7 +704,10 @@ static int caam_probe(struct platform_device *pdev)
> ent_delay);
> kick_trng(pdev, ent_delay);
> ent_delay += 400;
> + } else if (ctrlpriv->rng4_sh_init && inst_handles) {
> + ent_delay += 400;
> }
If both RNG state handles are initialized before kernel runs, then
instantiate_rng() should be a no-op and return 0, which is enough to exit the
loop: while ((ret == -EAGAIN) && (ent_delay < RTSDCTL_ENT_DLY_MAX))
If the loop cannot exit based on value of "ret" != -EAGAIN, then it means
caam_probe() will eventually fail due to ret == -EAGAIN:
if (ret) {
dev_err(dev, "failed to instantiate RNG");
goto caam_remove;
}
Please provide more details, so that the root cause is found and fixed.
For e.g. what is the value of RDSTA (RNG DRNG Status register @0x6C0):
-before & after u-boot initializes RNG
-as seen by kernel during caam_probe()
Also provide related error messages displayed during boot.
Thanks,
Horia
