Add entropy to the kernel CPRNG.
#include <zircon/syscalls.h> zx_status_t zx_cprng_add_entropy(const void* buffer, size_t buffer_size);
zx_cprng_add_entropy() mixes the given entropy into the kernel CPRNG. a privileged operation. It will accept at most ZX_CPRNG_ADD_ENTROPY_MAX_LEN bytes of entropy at a time.
zx_cprng_add_entropy() returns ZX_OK on success.
ZX_ERR_INVALID_ARGS buffer_size is too large, or buffer is not a valid userspace pointer.
This syscall should be very privileged.