[PATCH v2 2/2] x86/purgatory: Fix sparse warning, symbol not declared

["Tobin C. Harding" <me@tobin.cc>]

Sparse emits warning, 'symbol not declared' for a function that has
neither file scope nor a forward declaration. The functions only call
site is an ASM file.

Add a header file with the function declaration. Include the
header file in the C source file defining the function in order
to fix the sparse warning. Include the header file in ASM file
containing the call site thereby adding documentation of usage.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
---
 arch/x86/purgatory/purgatory.c    | 1 +
 arch/x86/purgatory/purgatory.h    | 7 +++++++
 arch/x86/purgatory/setup-x86_64.S | 3 ++-
 3 files changed, 10 insertions(+), 1 deletion(-)
 create mode 100644 arch/x86/purgatory/purgatory.h

diff --git a/arch/x86/purgatory/purgatory.c b/arch/x86/purgatory/purgatory.c
index 2a5f437..b6d5c89 100644
--- a/arch/x86/purgatory/purgatory.c
+++ b/arch/x86/purgatory/purgatory.c
@@ -11,6 +11,7 @@
  */
 
 #include "sha256.h"
+#include "purgatory.h"
 #include "../boot/string.h"
 
 struct sha_region {
diff --git a/arch/x86/purgatory/purgatory.h b/arch/x86/purgatory/purgatory.h
new file mode 100644
index 0000000..b2e859f
--- /dev/null
+++ b/arch/x86/purgatory/purgatory.h
@@ -0,0 +1,7 @@
+#ifndef PURGATORY_H
+#define PURGATORY_H
+
+extern void purgatory(void);
+
+#endif /* PURGATORY_H */
+
diff --git a/arch/x86/purgatory/setup-x86_64.S b/arch/x86/purgatory/setup-x86_64.S
index fe3c91b..7ed06e9 100644
--- a/arch/x86/purgatory/setup-x86_64.S
+++ b/arch/x86/purgatory/setup-x86_64.S
@@ -9,7 +9,8 @@
  * This source code is licensed under the GNU General Public License,
  * Version 2.  See the file COPYING for more details.
  */
-
+ #include "purgatory.h"
+        
 	.text
 	.globl purgatory_start
 	.balign 16
-- 
2.7.4