| Message ID | 20221105204417.137001-1-Jason@zx2c4.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | hw_random: use add_hwgenerator_randomness() for early entropy | expand |
On Sat, Nov 5, 2022 at 9:44 PM Jason A. Donenfeld <Jason@zx2c4.com> wrote: > > Rather than calling add_device_randomness(), the add_early_randomness() > function should use add_hwgenerator_randomness(), so that the early > entropy can be potentially credited, which allows for the RNG to > initialize earlier without having to wait for the kthread to come up. > > Cc: Herbert Xu <herbert@gondor.apana.org.au> > Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> > --- > drivers/char/hw_random/core.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c > index cc002b0c2f0c..8c0819ce2781 100644 > --- a/drivers/char/hw_random/core.c > +++ b/drivers/char/hw_random/core.c > @@ -69,8 +69,10 @@ static void add_early_randomness(struct hwrng *rng) > mutex_lock(&reading_mutex); > bytes_read = rng_get_data(rng, rng_fillbuf, 32, 0); > mutex_unlock(&reading_mutex); > - if (bytes_read > 0) > - add_device_randomness(rng_fillbuf, bytes_read); > + if (bytes_read > 0) { > + size_t entropy = bytes_read * 8 * rng->quality / 1024; > + add_hwgenerator_randomness(rng_fillbuf, bytes_read, entropy); > + } This will cause problems, because add_hwgenerator_randomness() will sleep. I'll look into a more robust change. Jason
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index cc002b0c2f0c..8c0819ce2781 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -69,8 +69,10 @@ static void add_early_randomness(struct hwrng *rng) mutex_lock(&reading_mutex); bytes_read = rng_get_data(rng, rng_fillbuf, 32, 0); mutex_unlock(&reading_mutex); - if (bytes_read > 0) - add_device_randomness(rng_fillbuf, bytes_read); + if (bytes_read > 0) { + size_t entropy = bytes_read * 8 * rng->quality / 1024; + add_hwgenerator_randomness(rng_fillbuf, bytes_read, entropy); + } } static inline void cleanup_rng(struct kref *kref)
Rather than calling add_device_randomness(), the add_early_randomness() function should use add_hwgenerator_randomness(), so that the early entropy can be potentially credited, which allows for the RNG to initialize earlier without having to wait for the kthread to come up. Cc: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> --- drivers/char/hw_random/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)