lib/thread: Verify threads are initialized before yielding

In hardwaremain.c we call console_init before threads_initialize. Part
of setting up the uart requires calling udelay which then calls
thread_yield_microseconds. Since threads have not been set up, trying to
yield will result in bad things happening. This change guards the thread
methods by making current_thread return NULL if the structures have not
been initialized.

BUG=b:179699789
TEST=Ramstage no longer hangs with serial enabled

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: If9e1eedfaebe584901d2937c8aa24e158706fa43
Reviewed-on: https://review.coreboot.org/c/coreboot/+/56318
Reviewed-by: Krystian Hebel <krystian.hebel@3mdeb.com>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions