On Wed, 2013-10-23 at 17:31 +0800, Tiejun Chen wrote: > In lazy EE magic, we may have a lazy interrupt occured while > entering kgdb, but we really don't want to replay that interrupt > for kgdb, so we have to clear the PACA_IRQ_HARD_DIS force to > make sure we can exit directly from this debug exception. > > Signed-off-by: Tiejun Chen <tiejun.c...@windriver.com>
s/stgep/step/ in subject > --- > arch/powerpc/kernel/kgdb.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c > index 447c14b..9872f58 100644 > --- a/arch/powerpc/kernel/kgdb.c > +++ b/arch/powerpc/kernel/kgdb.c > @@ -185,6 +185,14 @@ static int kgdb_singlestep(struct pt_regs *regs) > /* Restore current_thread_info lastly. */ > memcpy(exception_thread_info, backup_current_thread_info, > sizeof *thread_info); > > +#ifdef CONFIG_PPC64 > + /* > + * Clear the PACA_IRQ_HARD_DIS from the pending mask > + * since we are about to exit this directly from debug > + * exception without any replay interrupt in lazy EE case. > + */ > + local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS; > +#endif > return 1; > } > What happens to those interrupts you discarded once we get back to a state when they can be safely replayed? I don't think just dropping them is the answer. I'm not sure what the actual problem is. I can understand not wanting kgdb to cause interrupts to appear to run when the interrupted context has external interrupts disabled, but the replay code in entry_64.S doesn't run if interrupts are soft-disabled in the context to be returned to. What harm does it cause to run the interrupts if we're returning to an EE=1 context? Does KGDB enable interrupts in its handler? If not, how do we even get into the situation where there are interrupts pending when the interrupted context has EE soft-enabled (i.e. we went directly from a context where the interrupt handler should have run, to a hard-disabled context)? -Scott _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
