kernel/smp: Provide boot-time timeout for CSD lock diagnostics
Debugging of problems involving insanely long-running SMI handlers
proceeds better if the CSD-lock timeout can be adjusted. This commit
therefore provides a new smp.csd_lock_timeout kernel boot parameter
that specifies the timeout in milliseconds. The default remains at the
previously hard-coded value of five seconds.
[ paulmck: Apply feedback from Juergen Gross. ]
Cc: Rik van Riel <riel@surriel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>