From 21db79e8bb054d0351a6b1b464f1c9c47a2e6e8d Mon Sep 17 00:00:00 2001
From: Petr Tesarik <ptesarik@suse.com>
Date: Tue, 2 Aug 2016 14:06:16 -0700
Subject: kexec: add a kexec_crash_loaded() function

Provide a wrapper function to be used by kernel code to check whether a
crash kernel is loaded.  It returns the same value that can be seen in
/sys/kernel/kexec_crash_loaded by userspace programs.

I'm exporting the function, because it will be used by Xen, and it is
possible to compile Xen modules separately to enable the use of PV
drivers with unmodified bare-metal kernels.

Link: http://lkml.kernel.org/r/20160713121955.14969.69080.stgit@hananiah.suse.cz
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 kernel/kexec_core.c | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'kernel/kexec_core.c')

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 73d4c5f57dd8a..704534029a003 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -95,6 +95,12 @@ int kexec_should_crash(struct task_struct *p)
 	return 0;
 }
 
+int kexec_crash_loaded(void)
+{
+	return !!kexec_crash_image;
+}
+EXPORT_SYMBOL_GPL(kexec_crash_loaded);
+
 /*
  * When kexec transitions to the new kernel there is a one-to-one
  * mapping between physical and virtual addresses.  On processors
-- 
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