[PATCH] ppc64-xmon-stop-cpu.patch

[PATCH] ppc64-xmon-stop-cpu.patch

[David Wilder]

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Please pick up this patch
- During CPU(s) hang scenarios, kdump could not stop these CPUs. 
However, the user could invoke soft-reset to shoot down CPUs reliably. 
But, when the debugger is enabled, these CPUs are returned to hang state 
after they exited from the debugger. This patch fixes this issue by 
calling crash_kexec_secondary() before returns to previous state.

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


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- During CPU(s) hang scenarios, kdump could not stop these CPUs. However, the user could invoke soft-reset to shoot down CPUs reliably. But, when the debugger is enabled, these CPUs are returned to hang state after they exited from the debugger. This patch fixes this issue by calling crash_kexec_secondary() before returns to previous state.

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


diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 064a525..9a509f8 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -208,6 +208,16 @@ void system_reset_exception(struct pt_re
 
 	die("System Reset", regs, SIGABRT);
 
+	/*
+	 * Some CPUs which got released from debugger will execute this path.
+	 * These CPUs entered debugger first time via soft-reset - Means,
+	 * could be possible that these CPUs may not repond to an IPI later.
+	 * Therefore, has to call kdump func directly.
+	 * Not a problem if we exited from debugger to recover. In this case
+	 * there will not be any primary kexec CPU. Hence, will be returned.
+	 */
+	crash_kexec_secondary(regs);
+
 	/* Must die if the interrupt is not recoverable */
 	if (!(regs->msr & MSR_RI))
 		panic("Unrecoverable System Reset");