This work is derived from Daniel's prior work here [1]. It has been rebased (tag: kgdb-5.8-rc1 + console hardening patch-set[2]), reworked to use serial RX interrupt as NMI (pseudo NMI on aarch64) in order to drop into debugger and tested on Developerbox (using amba-pl011). - Patch #1 is more of a fix required for NMI console to replace kgdb IO console. - Patches #2 to #6 adds an architecture agnostic fallback mechanism to enable kgdb NMI console using serial RX interrupt as NMI. - Patch #7 is an optimization patch that gets rid of inefficient timer based tasklet and rather uses irq_work. Usage of kgdb NMI console: - Enable "CONFIG_SERIAL_KGDB_NMI". - Kernel cmdline modification for Developerbox: console=ttyNMI0 kgdboc=ttyAMA0 [1] https://git.linaro.org/people/daniel.thompson/linux.git/log/?h=kgdb/polled_request_irq [2] https://lkml.org/lkml/2020/6/4/294 Daniel Thompson (5): tty: serial: Add poll_get_irq() to the polling interface kgdb: Add request_nmi() to the io ops table for kgdboc serial: kgdb_nmi: Add support for interrupt based fallback serial: 8250: Implement poll_get_irq() interface serial: kgdb_nmi: Replace hrtimer with irq_work ping Sumit Garg (2): serial: kgdb_nmi: Allow NMI console to replace kgdb IO console serial: amba-pl011: Implement poll_get_irq() interface drivers/tty/serial/8250/8250_port.c | 16 ++++++ drivers/tty/serial/amba-pl011.c | 12 +++++ drivers/tty/serial/kgdb_nmi.c | 100 ++++++++++++++++++++++++------------ drivers/tty/serial/kgdboc.c | 35 +++++++++++++ drivers/tty/serial/serial_core.c | 18 +++++++ include/linux/kgdb.h | 7 +++ include/linux/serial_core.h | 1 + include/linux/tty_driver.h | 1 + 8 files changed, 158 insertions(+), 32 deletions(-) -- 2.7.4
