libpayload: Provide selfboot function.

The calling convention of payload entry function is different by architecture.
For example, X86 takes no arguments and ARM needs first param to be a
cb_header_ptr*.

To help payloads load and execute other payloads easily and correctly, we should
provide the selfboot() function in libpayload, using same prototype as defined
in coreboot environment.

BUG=none
TEST=emerge-nyan libpayload # pass
BRANCH=none

Original-Change-Id: I8f1cb2c0df788794b2f6f7f5500a3910328a4f84
Original-Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/199503
Original-Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
(cherry picked from commit 1e916cf021ce68886eb9668982c392eadedc7b7e)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I7279ef27f49ef581d25a455dd8f1f2f7f1ba58cb
Reviewed-on: http://review.coreboot.org/7907
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)

payloads/libpayload/arch/arm/Makefile.inc

@@ -38,6 +38,7 @@ libc-y += virtual.c
 libc-y += memcpy.S memset.S memmove.S
 libc-y += exception_asm.S exception.c
 libc-y += cache.c cpu.S
+libc-y += selfboot.c
 libcbfs-$(CONFIG_LP_CBFS) += dummy_media.c
 
 # Add other classes here when you put assembly files into them!

payloads/libpayload/arch/arm/selfboot.c

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <libpayload.h>
+
+extern void *cb_header_ptr;
+
+void selfboot(void *entry)
+{
+	__asm__ __volatile__(
+		"mov r0, %[cb_header_ptr]\n"
+		"bx %[entry]\n"
+		:: [cb_header_ptr]"r"(cb_header_ptr), [entry]"r"(entry)
+		: "r0"
+	);
+}

payloads/libpayload/arch/x86/Makefile.inc

@@ -31,6 +31,7 @@ head.o-y += head.S
 libc-y += main.c sysinfo.c
 libc-y += timer.c coreboot.c util.S
 libc-y += exec.S virtual.c
+libc-y += selfboot.c
 libc-y += string.c
 libc-y += exception_asm.S exception.c
 

payloads/libpayload/arch/x86/selfboot.c

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+#include <libpayload.h>
+
+void selfboot(void *entry)
+{
+	void (*entry_func)(void) = entry;
+	entry_func();
+}

payloads/libpayload/include/cbfs.h

@@ -82,8 +82,7 @@ void *cbfs_simple_buffer_unmap(struct cbfs_simple_buffer *buffer,
 int run_address(void *f);
 
 /* Defined in src/lib/selfboot.c */
-struct lb_memory;
-int selfboot(struct lb_memory *mem, struct cbfs_payload *payload);
+void selfboot(void *entry);
 
 /* Defined in individual arch / board implementation. */
 int init_default_cbfs_media(struct cbfs_media *media);