Drivers: hv: vmbus: Move the crash notification function

As part of the effort to separate out architecture specific code, move the
crash notification function.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 860233a..ce5fc73 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -209,3 +209,29 @@ u64 hv_do_hypercall(u64 control, void *input, void *output)
 #endif /* !x86_64 */
 }
 EXPORT_SYMBOL_GPL(hv_do_hypercall);
+
+void hyperv_report_panic(struct pt_regs *regs)
+{
+	static bool panic_reported;
+
+	/*
+	 * We prefer to report panic on 'die' chain as we have proper
+	 * registers to report, but if we miss it (e.g. on BUG()) we need
+	 * to report it on 'panic'.
+	 */
+	if (panic_reported)
+		return;
+	panic_reported = true;
+
+	wrmsrl(HV_X64_MSR_CRASH_P0, regs->ip);
+	wrmsrl(HV_X64_MSR_CRASH_P1, regs->ax);
+	wrmsrl(HV_X64_MSR_CRASH_P2, regs->bx);
+	wrmsrl(HV_X64_MSR_CRASH_P3, regs->cx);
+	wrmsrl(HV_X64_MSR_CRASH_P4, regs->dx);
+
+	/*
+	 * Let Hyper-V know there is crash data available
+	 */
+	wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
+}
+EXPORT_SYMBOL_GPL(hyperv_report_panic);