On Mon, 10 Sep 2012 10:57:04 -0700 Anton Vorontsov anton.vorontsov@linaro.org wrote:
On Mon, Sep 10, 2012 at 12:16:24PM +0100, Alan Cox wrote:
serial port, the CPU receives NMI exception, and we fall into KDB shell. So, it is our "debug console", and it is able to interrupt (and thus debug) even IRQ handlers themselves.
You seem to have an assumption of single core here. What happens if the NMI hits CPU #0 and the serial IRQ hits CPU #1 simultaneously ?
If you can't redirect all serial IRQs to NMI context, e.g. sometimes you get NMIs, sometimes IRQs, then your NMI handling is not deterministic, and surely this is not supported.
This seems like arch specific magic leaking into the tty code. Surely this should be buried in the depths of the platform IRQ code ?
Alan