libpayload: Add support for memory barriers

Add support for memory barriers in arch {arm,arm64,x86}. This is required to
force strict CPU ordering. Definitions are based on FREEBSD atomic.h
definitions.

BUG=chrome-os-partner:31533
BRANCH=None
TEST=Memory barriers tested with ehci driver on arm64

Change-Id: I50060b0f33a6bd6cb95e829df079df379b2ff2a5
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 937d66cdab92a8521ede8307f5af8f5c20d3e552
Original-Change-Id: Ie51e3452f7a254b24111000da5dbe8714ac22223
Original-Signed-off-by: Furquan Shaikh <furquan@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/213916
Original-Tested-by: Furquan Shaikh <furquan@chromium.org>
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Original-Commit-Queue: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: http://review.coreboot.org/8731
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

1 files changed, 38 insertions, 0 deletions

diff --git a/payloads/libpayload/include/x86/arch/barrier.h b/payloads/libpayload/include/x86/arch/barrier.h
new file mode 100644
index 0000000000..5e2cfec186
--- /dev/null
+++ b/payloads/libpayload/include/x86/arch/barrier.h
@@ -0,0 +1,38 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2014 Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ */
+
+#ifndef __ARCH_BARRIER_H_
+#define __ARCH_BARRIER_H__
+
+#define mb()
+#define rmb()
+#define wmb()
+
+#endif /* __ARCH_BARRIER_H__ */