[PATCH] hotplug: eliminate warning "Unknown IPI message 0x1"

[Russell King - ARM Linux]

On Fri, Feb 10, 2012 at 05:27:53PM +0800, Bill Carson wrote:
> When playing hotplug on vexpress board, a tiny warning pops out.
> 
> /sys/devices/system/cpu # echo 0 > cpu3/online
> CPU3: shutdown
> /sys/devices/system/cpu # echo 1 > cpu3/online
> CPU3: Booted secondary processor
> Calibrating delay loop (skipped) already calibrated this CPU
> CPU3: Unknown IPI message 0x1
>       ^^^^^^^
> It's a phony warning caused by handle_IPI as a result of calling
> gic_raise_softirq(cpumask_of(cpu), 1). Introducing a new ipi_msg_type
> IPI_WAKEUP_CPU to make this warning go away.

NAK.  I want people to move to SGI0 for this, so that we can have SGI1-N
as the proper IPIs.  The reason _I_ haven't done this is because it's
totally unclear whether anyone relies on the current IPI number.