arm: Move libgcc assembly macros to arch/asm.h

libgcc/macros.h contains some useful assembly macros that are common in
Linux kernel code and facilitate things such as unified ARM/THUMB
assembly. This patch moves it to a more general place where it can be
used by other code as well.

Change-Id: If68e8930aaafa706c54cf9a156fac826b31bb193
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/182178
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
(cherry picked from commit a780670def94a969829811fa8cf257f12b88f085)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6917
Tested-by: build bot (Jenkins)
Reviewed-by: David Hendricks <dhendrix@chromium.org>

3 files changed, 60 insertions, 15 deletions

diff --git a/payloads/libpayload/arch/arm/head.S b/payloads/libpayload/arch/arm/head.S
index 7a706e3aa6..0d23c7256f 100644
--- a/payloads/libpayload/arch/arm/head.S
+++ b/payloads/libpayload/arch/arm/head.S
@@ -27,17 +27,16 @@
  * SUCH DAMAGE.
  */
 
-	.global _entry, _leave
-	.text
-	.align 4
+#include <arch/asm.h>
 
 1:
+.align 4
 .word	_stack
 
 /*
  * Our entry point
  */
-_entry:
+ENTRY(_entry)
 
 	/* TODO: disable interrupts */
 
@@ -46,14 +45,15 @@ _entry:
 	/* Setup new stack */
 	ldr sp, 1b
 
-	/* TODO: Save old stack pointer */
+	/* TODO: Save old stack pointer and link register */
 
 	/* Let's rock. */
-	b start_main
+	bl start_main
 
-	/* %eax has the return value - pass it on unmolested */
-_leave:
-	/* TODO: restore old stack pointer. */
+	/* %r0 has the return value - pass it on unmolested */
+
+	/* TODO: restore old stack pointer and link register */
 
 	/* Return to the original context. */
-	mov pc, lr
+	bx lr
+ENDPROC(_entry)
diff --git a/payloads/libpayload/arch/arm/util.S b/payloads/libpayload/arch/arm/util.S
index e3f173eb2d..7c14a39a4f 100644
--- a/payloads/libpayload/arch/arm/util.S
+++ b/payloads/libpayload/arch/arm/util.S
@@ -27,11 +27,9 @@
  * SUCH DAMAGE.
  */
 
-	.global halt
-	.text
-	.align 4
+#include <arch/asm.h>
 
 /* This function puts the system into a halt. */
-	.type halt, function
-halt:
+ENTRY(halt)
 	b halt
+ENDPROC(halt)
diff --git a/payloads/libpayload/include/arm/arch/asm.h b/payloads/libpayload/include/arm/arch/asm.h
new file mode 100644
index 0000000000..1c3f7a21c3
--- /dev/null
+++ b/payloads/libpayload/include/arm/arch/asm.h
@@ -0,0 +1,47 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2013 Google Inc.
+ *
+ * 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; version 2 of the License.
+ *
+ * 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 __ARM_ASM_H
+#define __ARM_ASM_H
+
+#if defined __arm__
+#  define ARM(x...)	x
+#  define THUMB(x...)
+#elif defined __thumb__
+#  define ARM(x...)
+#  define THUMB(x...)	x
+#else
+#  error Not in ARM or thumb mode!
+#endif
+
+#define ALIGN .align 0
+
+#define ENDPROC(name) \
+	.type name, %function; \
+	END(name)
+
+#define ENTRY(name) \
+	.globl name; \
+	ALIGN; \
+	name:
+
+#define END(name) \
+	.size name, .-name
+
+#endif	/* __ARM_ASM_H */