core/riscv-rv32i: set in_interrupt at beginning of exception handler

There are 3 paths when receiving an excaption in
core/riscv-rv32i/init.S:
1. __irq_handler
2. excep_handler
3. unhandled_interrupt

Originally, in_interrupt_context() returns true only if it goes to 1st
path.  However, the rest paths are also in interrupt context, especially
some function may rely on in_interrupt_context(), for example,
uart_flush_output() in common/uart_buffering.c.

Note that, only the 1st goes back to normal context.  The rest of paths
are all going to panic and reset.

Sets in_interrupt at the beginning of exception handler instead of
start_irq_handler() so that the flag is ON when receiving an exception.

BRANCH=none
BUG=b:180571536
BUG=b:163300760
TEST=make BOARD=asurada_scp

Signed-off-by: Tzung-Bi Shih <tzungbi@chromium.org>
Change-Id: Iba689c506c02c4b5bb1668766f1d7ab5f86f72a4
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2702999
Reviewed-by: Eric Yilun Lin <yllin@chromium.org>

0 files changed, 0 insertions, 0 deletions