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From:   Dmitry Safonov <dima@arista.com>
To:     linux-kernel@vger.kernel.org
Cc:     Dmitry Safonov <dima@arista.com>, Adrian Reber <adrian@lisas.de>,
        Andrei Vagin <avagin@openvz.org>,
        Andrei Vagin <avagin@gmail.com>,
        Andy Lutomirski <luto@kernel.org>,
        Andy Tucker <agtucker@google.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        Cyrill Gorcunov <gorcunov@openvz.org>,
        Dmitry Safonov <0x7f454c46@gmail.com>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        Jeff Dike <jdike@addtoit.com>, Oleg Nesterov <oleg@redhat.com>,
        Pavel Emelyanov <xemul@virtuozzo.com>,
        Shuah Khan <shuah@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        containers@lists.linux-foundation.org, criu@openvz.org,
        linux-api@vger.kernel.org, x86@kernel.org
Subject: [PATCH 22/32] timens: Add align for timens_offsets
Date:   Wed,  6 Feb 2019 00:10:56 +0000
Message-Id: <20190206001107.16488-23-dima@arista.com>
In-Reply-To: <20190206001107.16488-1-dima@arista.com>
References: <20190206001107.16488-1-dima@arista.com>
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Align offsets so that time namespace will work for ia32 applications on
x86_64 host.

Signed-off-by: Dmitry Safonov <dima@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 777530c46852..f2a03d4f7a91 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_time_offset;
-	struct timespec64  monotonic_boottime_offset;
+	struct timespec64  monotonic_time_offset __aligned(8);
+	struct timespec64  monotonic_boottime_offset __aligned(8);
 };
 
 #endif
-- 
2.20.1