| Message ID | 56b0c0f2834cba63db1f75966f2ee756ab347205.1399594544.git.geoff@infradead.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, May 09, 2014 at 01:48:17AM +0100, Geoff Levand wrote: > Add two new minimal routines smp_spin_table_cpu_disable() and > smp_spin_table_cpu_die() and hook them up to the smp_spin_table_ops instance. > > Kexec support will use smp_spin_table_cpu_die() for re-boot of spin table CPUs, > but also needs a compatible smp_spin_table_cpu_disable() to allow > execution to reach smp_spin_table_cpu_die(). > > Signed-off-by: Geoff Levand <geoff@infradead.org> > --- > arch/arm64/kernel/smp_spin_table.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/arch/arm64/kernel/smp_spin_table.c b/arch/arm64/kernel/smp_spin_table.c > index 7a530d2..26c780b 100644 > --- a/arch/arm64/kernel/smp_spin_table.c > +++ b/arch/arm64/kernel/smp_spin_table.c > @@ -142,10 +142,23 @@ static void smp_spin_table_cpu_postboot(void) > raw_spin_unlock(&boot_lock); > } > > +static int smp_spin_table_cpu_disable(unsigned int cpu) > +{ > + return 0; If we cannot kill the CPU then we need to fail here. cpu_disable is called early enough that the cpu hotplug infrastructure can recover if we cannot disable the CPU. > +} > + > +static void smp_spin_table_cpu_die(unsigned int cpu) > +{ > + while (1) > + cpu_relax(); This does not kill the CPU -- it's stuck spinning on some instructions that might get clobbered upon a kexec. So this is insufficient for kexec. This also doesn't allow the CPU to be brought back, so it's completely useless as-is. NAK for pseudo-hotplug. If we cannot place the CPU somewhere out of the way of the kernel then we _must_ fail. Thanks, Mark. > +} > + > const struct cpu_operations smp_spin_table_ops = { > .name = "spin-table", > .cpu_init = smp_spin_table_cpu_init, > .cpu_prepare = smp_spin_table_cpu_prepare, > .cpu_boot = smp_spin_table_cpu_boot, > .cpu_postboot = smp_spin_table_cpu_postboot, > + .cpu_disable = smp_spin_table_cpu_disable, > + .cpu_die = smp_spin_table_cpu_die, > }; > -- > 1.9.1 > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
diff --git a/arch/arm64/kernel/smp_spin_table.c b/arch/arm64/kernel/smp_spin_table.c index 7a530d2..26c780b 100644 --- a/arch/arm64/kernel/smp_spin_table.c +++ b/arch/arm64/kernel/smp_spin_table.c @@ -142,10 +142,23 @@ static void smp_spin_table_cpu_postboot(void) raw_spin_unlock(&boot_lock); } +static int smp_spin_table_cpu_disable(unsigned int cpu) +{ + return 0; +} + +static void smp_spin_table_cpu_die(unsigned int cpu) +{ + while (1) + cpu_relax(); +} + const struct cpu_operations smp_spin_table_ops = { .name = "spin-table", .cpu_init = smp_spin_table_cpu_init, .cpu_prepare = smp_spin_table_cpu_prepare, .cpu_boot = smp_spin_table_cpu_boot, .cpu_postboot = smp_spin_table_cpu_postboot, + .cpu_disable = smp_spin_table_cpu_disable, + .cpu_die = smp_spin_table_cpu_die, };
Add two new minimal routines smp_spin_table_cpu_disable() and smp_spin_table_cpu_die() and hook them up to the smp_spin_table_ops instance. Kexec support will use smp_spin_table_cpu_die() for re-boot of spin table CPUs, but also needs a compatible smp_spin_table_cpu_disable() to allow execution to reach smp_spin_table_cpu_die(). Signed-off-by: Geoff Levand <geoff@infradead.org> --- arch/arm64/kernel/smp_spin_table.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)