As long as MBEDTLS_ENTROPY_C is enabled, Mbed TLS needs to
poll some entropy source to gather data that will then be
processed by CTR/HMAC-DRBG modules. This means that in most
of the cases, once MBEDTLS_ENTROPY_C is enabled then also
MBEDTLS_ENTROPY_POLL_ZEPHYR needs to be enabled. This was
done manually until now, as the long list of samples/tests
demonstrate.
This commit solves this dependency by defaulting
MBEDTLS_ENTROPY_POLL_ZEPHYR to on as soon as
MBEDTLS_ENTROPY_C is set. As a consequence, all manual
enablement of MBEDTLS_ENTROPY_POLL_ZEPHYR in samples/tests
are removed.
Signed-off-by: Valerio Setti <vsetti@baylibre.com>
- Slightly improve the name of this kconfig adding the suffix
_POLL in order to highlight that this adds a callback
function used to poll data.
- Description was also updated to point out that this symbols
might not only use the (secure) entropy driver, but also
generic number generators, some of which are not really
secure.
- The symbol was move from Kconfig to Kconfig.tls-generic because
this is where MBEDTLS_ENTROPY_C is located and since
MBEDTLS_ENTROPY_HARDWARE_ALT depends on the former (it only
makes sense if the entropy module is also enabled), we add
also the "depends on".
Signed-off-by: Valerio Setti <vsetti@baylibre.com>
