From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Wed, 4 Mar 2015 06:13:48 +0000 (-0800)
Subject: 3.19-stable patches
X-Git-Tag: v3.10.71~12
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=eb030ba65b0a5ebdc6ce597f95ccd11444ff0f47;p=thirdparty%2Fkernel%2Fstable-queue.git

3.19-stable patches

added patches:
	x86-xen-p2m-replace-access_once-with-read_once.patch
---

diff --git a/queue-3.19/series b/queue-3.19/series
index 87233685ea9..58226a5a53d 100644
--- a/queue-3.19/series
+++ b/queue-3.19/series
@@ -172,3 +172,4 @@ kernel-tighten-rules-for-access-once.patch
 kernel-fix-sparse-warning-for-access_once.patch
 kernel-make-read_once-valid-on-const-arguments.patch
 x86-spinlocks-paravirt-fix-memory-corruption-on-unlock.patch
+x86-xen-p2m-replace-access_once-with-read_once.patch
diff --git a/queue-3.19/x86-xen-p2m-replace-access_once-with-read_once.patch b/queue-3.19/x86-xen-p2m-replace-access_once-with-read_once.patch
new file mode 100644
index 00000000000..e072658282b
--- /dev/null
+++ b/queue-3.19/x86-xen-p2m-replace-access_once-with-read_once.patch
@@ -0,0 +1,36 @@
+From 1760f1eb7ec485197bd3a8a9c13e4160bb740275 Mon Sep 17 00:00:00 2001
+From: Christian Borntraeger <borntraeger@de.ibm.com>
+Date: Sun, 7 Dec 2014 22:01:59 +0100
+Subject: x86/xen/p2m: Replace ACCESS_ONCE with READ_ONCE
+
+From: Christian Borntraeger <borntraeger@de.ibm.com>
+
+commit 1760f1eb7ec485197bd3a8a9c13e4160bb740275 upstream.
+
+ACCESS_ONCE does not work reliably on non-scalar types. For
+example gcc 4.6 and 4.7 might remove the volatile tag for such
+accesses during the SRA (scalar replacement of aggregates) step
+(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145)
+
+Change the p2m code to replace ACCESS_ONCE with READ_ONCE.
+
+Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
+Reviewed-by: Juergen Gross <jgross@suse.com>
+Acked-by: David Vrabel <david.vrabel@citrix.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/x86/xen/p2m.c |    2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/arch/x86/xen/p2m.c
++++ b/arch/x86/xen/p2m.c
+@@ -554,7 +554,7 @@ static bool alloc_p2m(unsigned long pfn)
+ 		mid_mfn = NULL;
+ 	}
+ 
+-	p2m_pfn = pte_pfn(ACCESS_ONCE(*ptep));
++	p2m_pfn = pte_pfn(READ_ONCE(*ptep));
+ 	if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) ||
+ 	    p2m_pfn == PFN_DOWN(__pa(p2m_missing))) {
+ 		/* p2m leaf page is missing */