[PATCH] Xmon stops CPUs for kdump

[David Wilder]

In the case of a system hang, the user will invoke soft-reset to 
initiate the kdump boot.  If xmon is enabled, the CPU(s) enter into the 
xmon debugger.   Unfortunately, the secondary CPU(s) will return to the 
hung state when they exit from the debugger (returned from die() -> 
system_reset_exception()).  This causes a problem in kdump since the 
hung CPU(s) will not respond to the IPI sent from kdump.  This patch 
fixes the issue by calling crash_kexec_secondary() directly from 
system_reset_exception() without returning to the previous state.  These 
secondary CPUs wait 5ms until the kdump boot is started by the primary 
CPU.   In the case we exited from the debugger to "recover" (command 'x' 
in xmon) the primary and the secondary CPUs will all return from die() 
-> system_reset_exception() ->crash_kexec_secondary() wait 5ms, then 
return to the previous state.  A kdump boot is not started in this case.

Signed-off-by: Haren Myneni <haren at us.ibm.com>
Signed-off-by: David Wilder <dwilder at us.ibm.com>

-- 
David Wilder
IBM Linux Technology Center
Beaverton, Oregon, USA 
dwilder at us.ibm.com
(503)578-3789

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