> -----Original Message----- > From: Russell King - ARM Linux [mailto:linux at arm.linux.org.uk] > Sent: Monday, November 22, 2010 4:58 PM > To: Per Fransson; Shilimkar, Santosh > Cc: Mika Westerberg; kexec at lists.infradead.org; linux-arm- > kernel at lists.infradead.org > Subject: Re: [PATCH] Add call to non-crashing cores through IPI > > On Mon, Nov 22, 2010 at 10:47:40AM +0000, Russell King - ARM Linux wrote: > > However, we do need smp_send_stop() to wait for a limited time for the > > other CPUs to respond to the request. > > ARM: smp: make smp_send_stop() wait for secondary CPUs to stop > > Wait up to one second for secondary CPUs to respond to a request to > stop. This avoids the sender CPU continuing and possibly destroying > state before the recipients have had a chance to respond to the stop. > However, if the recipients have crashed, we won't hang the sender > CPU indefinitely. > Just tried this patch thinking it might fix the reboot issue reported earlier. But it doesn't help. > Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk> > --- > arch/arm/kernel/smp.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c > index 5d0dc16..32a2158 100644 > --- a/arch/arm/kernel/smp.c > +++ b/arch/arm/kernel/smp.c > @@ -589,10 +589,16 @@ void smp_send_reschedule(int cpu) > > void smp_send_stop(void) > { > + unsigned long timeout; > cpumask_t mask = cpu_online_map; > cpu_clear(smp_processor_id(), mask); > if (!cpus_empty(mask)) > send_ipi_message(&mask, IPI_CPU_STOP); > + > + /* Wait up to one second for other CPUs to stop */ > + timeout = USEC_PER_SEC; > + while (num_online_cpus() > 1 && timeout--) > + udelay(1); > } > > /*
