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BugLink: https://bugs.launchpad.net/bugs/1892822

commit 9cce844a

 upstream.

Now CPU#0 is not hotpluggable on MIPS, so prevent to create /sys/devices
/system/cpu/cpu0/online which confuses some user-space tools.

Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

Each platform has to add support for CPU hotplugging itself by providing
suitable definitions for the cpu_disable and cpu_die of the smp_ops
methods and setting SYS_SUPPORTS_HOTPLUG_CPU.  A platform should only set
SYS_SUPPORTS_HOTPLUG_CPU once all it's smp_ops definitions have the
necessary changes.  This patch contains the changes to the dummy smp_ops
definition for uni-processor systems.

Parts of the code contributed by Cavium Inc.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Otherwise CPU 0 doesn't show up in sysfs which breaks some software.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>