[PATCHv4 19/28] timens: Add align for timens_offsets

[Dmitry Safonov]

Align offsets so that time namespace will work for ia32 applications on
x86_64 host.

Co-developed-by: Andrei Vagin <avagin at openvz.org>
Signed-off-by: Andrei Vagin <avagin at openvz.org>
Signed-off-by: Dmitry Safonov <dima at arista.com>
---
 include/linux/timens_offsets.h | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/include/linux/timens_offsets.h b/include/linux/timens_offsets.h
index e93aabaa5e45..05da1b0563ce 100644
--- a/include/linux/timens_offsets.h
+++ b/include/linux/timens_offsets.h
@@ -2,9 +2,17 @@
 #ifndef _LINUX_TIME_OFFSETS_H
 #define _LINUX_TIME_OFFSETS_H
 
+/*
+ * Time offsets need align as they're placed on VVAR page,
+ * which is used by x86_64 and ia32 VDSO code.
+ * On ia32 offset::tv_sec (u64) has align(4), so re-align offsets
+ * to the same positions as 64-bit offsets.
+ * On 64-bit big-endian systems VDSO should convert to timespec64
+ * to timespec because of a padding occurring between the fields.
+ */
 struct timens_offsets {
-	struct timespec64 monotonic;
-	struct timespec64 boottime;
+	struct timespec64 monotonic __aligned(8);
+	struct timespec64 boottime __aligned(8);
 };
 
 #endif
-- 
2.22.0