On Thu, Apr 18, 2013 at 8:44 AM, Ralf Baechle <ralf@xxxxxxxxxxxxxx> wrote: > On Thu, Apr 18, 2013 at 03:13:55PM +0800, Lin Ming wrote: > >> I encounter a problem that cpu stuck with irq disabled, which is known >> as hard lockup. >> I know there is NMI hard lockup detector for x86, which can dump the >> back trace of the hard lockup. >> >> Is there any similar feature for MIPS? > > No, there isn't, unfortunately. > > This is because on MIPS an NMI is very different from for example x86. > An NMI goes straight to a firmware address and most firmware implementations > don't provided a suitable hook for an OS to gain control back from an NMI. > > Generally on MIPS NMIs are used to signal catastrophic problems, things > like a machine check exception but external to the CPU. > > One of the notable exceptions is Octeon where (see the Octeon watchdog > driver) an OS can regain control after an NMI. Malta and SGI IP27 also > have somewhat useful NMIs. > > Ralf
