* [PATCH 1/2] hwrng: optee: handle unlimited data rates
@ 2020-07-23 8:28 Jorge Ramirez-Ortiz
2020-07-23 8:28 ` [PATCH 2/2] hwrng: optee: fix wait use case Jorge Ramirez-Ortiz
0 siblings, 1 reply; 2+ messages in thread
From: Jorge Ramirez-Ortiz @ 2020-07-23 8:28 UTC (permalink / raw)
To: jorge, sumit.garg, mpm, herbert
Cc: jens.wiklander, arnd, ricardo, mike, gregkh, op-tee, linux-crypto
Data rates of MAX_UINT32 will schedule an unnecessary one jiffy
timeout on the call to msleep. Avoid this scenario by using 0 as the
unlimited data rate.
Signed-off-by: Jorge Ramirez-Ortiz <jorge@foundries.io>
---
drivers/char/hw_random/optee-rng.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/char/hw_random/optee-rng.c b/drivers/char/hw_random/optee-rng.c
index 49b2e02537dd..5bc4700c4dae 100644
--- a/drivers/char/hw_random/optee-rng.c
+++ b/drivers/char/hw_random/optee-rng.c
@@ -128,7 +128,7 @@ static int optee_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
data += rng_size;
read += rng_size;
- if (wait) {
+ if (wait && pvt_data->data_rate) {
if (timeout-- == 0)
return read;
msleep((1000 * (max - read)) / pvt_data->data_rate);
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH 2/2] hwrng: optee: fix wait use case
2020-07-23 8:28 [PATCH 1/2] hwrng: optee: handle unlimited data rates Jorge Ramirez-Ortiz
@ 2020-07-23 8:28 ` Jorge Ramirez-Ortiz
0 siblings, 0 replies; 2+ messages in thread
From: Jorge Ramirez-Ortiz @ 2020-07-23 8:28 UTC (permalink / raw)
To: jorge, sumit.garg, mpm, herbert
Cc: jens.wiklander, arnd, ricardo, mike, gregkh, op-tee, linux-crypto
The current code waits for data to be available before attempting a
second read. However the second read would not be executed as the
while loop exits.
This fix does not wait if all data has been read and reads a second
time if only partial data was retrieved on the first read.
Signed-off-by: Jorge Ramirez-Ortiz <jorge@foundries.io>
---
drivers/char/hw_random/optee-rng.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/char/hw_random/optee-rng.c b/drivers/char/hw_random/optee-rng.c
index 5bc4700c4dae..967d58bb9fda 100644
--- a/drivers/char/hw_random/optee-rng.c
+++ b/drivers/char/hw_random/optee-rng.c
@@ -122,13 +122,15 @@ static int optee_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
if (max > MAX_ENTROPY_REQ_SZ)
max = MAX_ENTROPY_REQ_SZ;
- while (read == 0) {
+ for (;;) {
rng_size = get_optee_rng_data(pvt_data, data, (max - read));
data += rng_size;
read += rng_size;
if (wait && pvt_data->data_rate) {
+ if (read == max)
+ return read;
if (timeout-- == 0)
return read;
msleep((1000 * (max - read)) / pvt_data->data_rate);
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
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