| Message ID | 20220420120601.1015362-1-festevam@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v5] crypto: caam - fix i.MX6SX entropy delay value | expand |
Reviewed-by: Gaurav Jain <gaurav.jain@nxp.com> > -----Original Message----- > From: Fabio Estevam <festevam@gmail.com> > Sent: Wednesday, April 20, 2022 5:36 PM > To: herbert@gondor.apana.org.au > Cc: Horia Geanta <horia.geanta@nxp.com>; Gaurav Jain > <gaurav.jain@nxp.com>; Varun Sethi <V.Sethi@nxp.com>; linux- > crypto@vger.kernel.org; Fabio Estevam <festevam@denx.de>; > stable@vger.kernel.org > Subject: [EXT] [PATCH v5] crypto: caam - fix i.MX6SX entropy delay value > > Caution: EXT Email > > From: Fabio Estevam <festevam@denx.de> > > Since commit 358ba762d9f1 ("crypto: caam - enable prediction resistance in > HRWNG") the following CAAM errors can be seen on i.MX6SX: > > caam_jr 2101000.jr: 20003c5b: CCB: desc idx 60: RNG: Hardware error > hwrng: no data available > > This error is due to an incorrect entropy delay for i.MX6SX. > > Fix it by increasing the minimum entropy delay for i.MX6SX as done in U-Boot: > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwo > rk.ozlabs.org%2Fproject%2Fuboot%2Fpatch%2F20220415111049.2565744-1- > gaurav.jain%40nxp.com%2F&data=05%7C01%7Cgaurav.jain%40nxp.com% > 7Cc2f2316c0db64170b59e08da22c62c4d%7C686ea1d3bc2b4c6fa92cd99c5c301 > 635%7C0%7C0%7C637860531804367821%7CUnknown%7CTWFpbGZsb3d8eyJ > WIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C > 3000%7C%7C%7C&sdata=OTgUAquesUW39%2F0bhSnXHDe4UpCU8dQN% > 2B7P0hlE6oiE%3D&reserved=0 > > As explained in the U-Boot patch: > > "RNG self tests are run to determine the correct entropy delay. > Such tests are executed with different voltages and temperatures to identify the > worst case value for the entropy delay. For i.MX6SX, it was determined that > after adding a margin value of 1000 the minimum entropy delay should be at > least 12000." > > Cc: <stable@vger.kernel.org> > Fixes: 358ba762d9f1 ("crypto: caam - enable prediction resistance in HRWNG") > Signed-off-by: Fabio Estevam <festevam@denx.de> > Reviewed-by: Horia Geantă <horia.geanta@nxp.com> > --- > Changes since v4: > - Change the function name to needs_entropy_delay_adjustment() - Vabhav > - Improve the commit log by adding the explanation from the U-Boot patch - > Vabhav > > drivers/crypto/caam/ctrl.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c index > ca0361b2dbb0..f87aa2169e5f 100644 > --- a/drivers/crypto/caam/ctrl.c > +++ b/drivers/crypto/caam/ctrl.c > @@ -609,6 +609,13 @@ static bool check_version(struct fsl_mc_version > *mc_version, u32 major, } #endif > > +static bool needs_entropy_delay_adjustment(void) > +{ > + if (of_machine_is_compatible("fsl,imx6sx")) > + return true; > + return false; > +} > + > /* Probe routine for CAAM top (controller) level */ static int caam_probe(struct > platform_device *pdev) { @@ -855,6 +862,8 @@ static int caam_probe(struct > platform_device *pdev) > * Also, if a handle was instantiated, do not change > * the TRNG parameters. > */ > + if (needs_entropy_delay_adjustment()) > + ent_delay = 12000; > if (!(ctrlpriv->rng4_sh_init || inst_handles)) { > dev_info(dev, > "Entropy delay = %u\n", @@ -871,6 +880,15 @@ static > int caam_probe(struct platform_device *pdev) > */ > ret = instantiate_rng(dev, inst_handles, > gen_sk); > + /* > + * Entropy delay is determined via TRNG characterization. > + * TRNG characterization is run across different voltages > + * and temperatures. > + * If worst case value for ent_dly is identified, > + * the loop can be skipped for that platform. > + */ > + if (needs_entropy_delay_adjustment()) > + break; > if (ret == -EAGAIN) > /* > * if here, the loop will rerun, > -- > 2.25.1
On Wed, Apr 20, 2022 at 09:06:01AM -0300, Fabio Estevam wrote: > From: Fabio Estevam <festevam@denx.de> > > Since commit 358ba762d9f1 ("crypto: caam - enable prediction resistance > in HRWNG") the following CAAM errors can be seen on i.MX6SX: > > caam_jr 2101000.jr: 20003c5b: CCB: desc idx 60: RNG: Hardware error > hwrng: no data available > > This error is due to an incorrect entropy delay for i.MX6SX. > > Fix it by increasing the minimum entropy delay for i.MX6SX > as done in U-Boot: > https://patchwork.ozlabs.org/project/uboot/patch/20220415111049.2565744-1-gaurav.jain@nxp.com/ > > As explained in the U-Boot patch: > > "RNG self tests are run to determine the correct entropy delay. > Such tests are executed with different voltages and temperatures to identify > the worst case value for the entropy delay. For i.MX6SX, it was determined > that after adding a margin value of 1000 the minimum entropy delay should be > at least 12000." > > Cc: <stable@vger.kernel.org> > Fixes: 358ba762d9f1 ("crypto: caam - enable prediction resistance in HRWNG") > Signed-off-by: Fabio Estevam <festevam@denx.de> > Reviewed-by: Horia Geantă <horia.geanta@nxp.com> > --- > Changes since v4: > - Change the function name to needs_entropy_delay_adjustment() - Vabhav > - Improve the commit log by adding the explanation from the U-Boot > patch - Vabhav > > drivers/crypto/caam/ctrl.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) Patch applied. Thanks.
Hi! I found an older discussion on the same topic, where it is mentioned that the same problem also occurs on imx6dl, imx6d and imx6s: https://linuxlists.cc/l/4/linux-crypto/t/3843436/caam_rng_trouble#post4282922 I have also observed the problem on an imx6dl, running a 5.10.112 kernel. Therefore, the problem might persist for the other variants. BR BB
diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c index ca0361b2dbb0..f87aa2169e5f 100644 --- a/drivers/crypto/caam/ctrl.c +++ b/drivers/crypto/caam/ctrl.c @@ -609,6 +609,13 @@ static bool check_version(struct fsl_mc_version *mc_version, u32 major, } #endif +static bool needs_entropy_delay_adjustment(void) +{ + if (of_machine_is_compatible("fsl,imx6sx")) + return true; + return false; +} + /* Probe routine for CAAM top (controller) level */ static int caam_probe(struct platform_device *pdev) { @@ -855,6 +862,8 @@ static int caam_probe(struct platform_device *pdev) * Also, if a handle was instantiated, do not change * the TRNG parameters. */ + if (needs_entropy_delay_adjustment()) + ent_delay = 12000; if (!(ctrlpriv->rng4_sh_init || inst_handles)) { dev_info(dev, "Entropy delay = %u\n", @@ -871,6 +880,15 @@ static int caam_probe(struct platform_device *pdev) */ ret = instantiate_rng(dev, inst_handles, gen_sk); + /* + * Entropy delay is determined via TRNG characterization. + * TRNG characterization is run across different voltages + * and temperatures. + * If worst case value for ent_dly is identified, + * the loop can be skipped for that platform. + */ + if (needs_entropy_delay_adjustment()) + break; if (ret == -EAGAIN) /* * if here, the loop will rerun,