Create shared symbols for stage0 functions.

This fixes for example printk calls from initram code.

Signed-off-by: Stefan Reinauer <stepan@coresystems.de>
Acked-by: Jordan Crouse <jordan.crouse@amd.com>



git-svn-id: svn://coreboot.org/repository/LinuxBIOSv3@505 f3766cd6-281f-0410-b1cd-43a5c92072e9

include/shared.h

@@ -0,0 +1,73 @@
+/*
+ * This file is part of the LinuxBIOS project
+ *
+ * Copyright(C) 2007 coresystems GmbH
+ * Written by Stefan Reinauer <stepan@coresystems.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#ifndef SHARED_H
+#define SHARED_H
+
+#ifdef _SHARED
+/* _SHARED mode enforces some functions to be called with an
+ * absolute address, even in PIE mode. This is required since
+ * the relative distance between XIP code and stage 0 is not known
+ */
+#define FUNC(func, ret, attr, args...)   \
+	ret stage0_##func(args) attr
+#define EXTERN(func, ret, attr, args...) \
+	ret (*func)(args) attr= stage0_##func
+#else
+#define FUNC(func, ret, attr, args...)   \
+	ret func(args) attr
+#define EXTERN(func, ret, attr, args...)
+#endif
+
+/**
+ * Use the SHARED macro to create a universally usable function 
+ * prototype. This will create a function prototype in stage 0 and
+ * a function prototype plus a function pointer for all code compiled
+ * with _SHARED defined (required for XIP code)
+ *
+ * @func   function name
+ * @ret    return value
+ * @args   function arguments
+ */
+
+#define SHARED(func,ret,args...) \
+	FUNC(func,ret,,##args);  \
+	EXTERN(func,ret,,##args)
+
+
+/**
+ * Use the SHARED_WITH_ATTRIBUTES macro to create a universally usable function 
+ * prototype for a function using GCC attributes. 
+ * This macro works identically to SHARED(), but it adds a GCC attribute to the
+ * function. So far we use this to have printk parameters tested with a
+ * "format" attribute.
+ *
+ * @func   function name
+ * @ret    return value
+ * @attr   function attributes
+ * @args   function arguments
+ */
+
+#define SHARED_WITH_ATTRIBUTES(func,ret,attr,args...) \
+	FUNC(func,ret,attr,##args);  \
+	EXTERN(func,ret,attr,##args)
+
+#endif /* SHARED_H */