tree f255087706b9d176455b17e4384f4632f59f4cde
parent 88278ca27a43ae503572b52ea2c171fbf45db5a2
author David S. Miller <davem@davemloft.net> 1211265960 -0700
committer David S. Miller <davem@davemloft.net> 1211268825 -0700

sparc64: Add global register dumping facility.

When a cpu really is stuck in the kernel, it can be often
impossible to figure out which cpu is stuck where.  The
worst case is when the stuck cpu has interrupts disabled.

Therefore, implement a global cpu state capture that uses
SMP message interrupts which are not disabled by the
normal IRQ enable/disable APIs of the kernel.

As long as we can get a sysrq 'y' to the kernel, we can
get a dump.  Even if the console interrupt cpu is wedged,
we can trigger it from userspace using /proc/sysrq-trigger

The output is made compact so that this facility is more
useful on high cpu count systems, which is where this
facility will likely find itself the most useful :)

Signed-off-by: David S. Miller <davem@davemloft.net>