[dpdk-dev] [PATCH v4 0/2] eal: choose initial PRNG seed source at runtime

[Dan Gora <dg@adax.com>]

Hi All,

The following patches updates the rte_random subsystem to dynamically find
the best source of the initial seed to the PRNG at run time.

The first patch enables dynamic checking for the rdseed instruction and
removes the requirement for it on the execution system.  It also ensures
that the code to use the rdseed instruction is generated, even if the host
compilation system does not support it (on x86 systems).

The second patch emulates the getentropy() glibc function by reading bytes
from /dev/urandom.  This removes an unnecessary dependency on glibc 2.25.

v4:  Note that emulating getentropy by reading from /dev/urandom should
never fail, so now the question is if we should just remove the rdseed
method entirely since it's x86 only?  Should we remove the fallback to
rte_get_tsc_cycles()?

Thanks
Dan

-----
v2:
* Fix patch apply issue.
* dlclose() handle if dlsym() fails in __rte_getentropy().

v3:
* Fix error checking of dlsym() in __rte_getentropy().
* Style changes recommended by Mattias.

v4:
* Replace dlopen/dlsym method with reading from /dev/urandom.
* Try rdseed method before getentropy() method since the
  latter should never fail.



Dan Gora (2):
  eal: check for rdseed at run time for random seed
  eal: emulate glibc getentropy for initial random seed

 config/x86/meson.build             | 11 +++--
 lib/librte_eal/common/rte_random.c | 79 ++++++++++++++++++++++++------
 lib/librte_eal/meson.build         |  3 --
 mk/rte.cpuflags.mk                 |  9 +++-
 4 files changed, 79 insertions(+), 23 deletions(-)

-- 
2.24.1.425.g7034cd094b