[PATCH v3 2/5] crypto: caam: Fix endless loop when RNG is already initialized

From: Bryan O'Donoghue
Date: Tue Jan 30 2018 - 21:01:58 EST


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 GeantÄ" <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 instantiate_rng(...) fails, the loop will rerun
* and the kick_trng(...) function will modfiy the
--
2.7.4