[PATCH 1/8] livepatch: Create and include UAPI headers

[Joao Moreira]

From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>

Define klp prefixes in include/uapi/linux/livepatch.h, and use them for
replacing hard-coded values in kernel/livepatch/core.c.

Update MAINTAINERS.

Note: Add defines to uapi as these are also to be used by klp-convert, a
userspace tool that will be added in patch 03/07 of this same patch set.

[jmoreira: split up and changelog]

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Joao Moreira <jmoreira@xxxxxxx>
---
 MAINTAINERS                    |  1 +
 include/linux/livepatch.h      |  1 +
 include/uapi/linux/livepatch.h | 28 ++++++++++++++++++++++++++++
 kernel/livepatch/core.c        |  4 ++--
 4 files changed, 32 insertions(+), 2 deletions(-)
 create mode 100644 include/uapi/linux/livepatch.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 09b5ab6a8a5c..1d8ea36e1173 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7713,6 +7713,7 @@ R:	Petr Mladek <pmladek@xxxxxxxx>
 S:	Maintained
 F:	kernel/livepatch/
 F:	include/linux/livepatch.h
+F:	include/uapi/linux/livepatch.h
 F:	arch/x86/include/asm/livepatch.h
 F:	arch/x86/kernel/livepatch.c
 F:	Documentation/livepatch/
diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
index 194991ef9347..96a75be7ef50 100644
--- a/include/linux/livepatch.h
+++ b/include/linux/livepatch.h
@@ -24,6 +24,7 @@
 #include <linux/module.h>
 #include <linux/ftrace.h>
 #include <linux/completion.h>
+#include <uapi/linux/livepatch.h>
 
 #if IS_ENABLED(CONFIG_LIVEPATCH)
 
diff --git a/include/uapi/linux/livepatch.h b/include/uapi/linux/livepatch.h
new file mode 100644
index 000000000000..bc35f85fd859
--- /dev/null
+++ b/include/uapi/linux/livepatch.h
@@ -0,0 +1,28 @@
+/*
+ * livepatch.h - Kernel Live Patching Core
+ *
+ * Copyright (C) 2016 Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _UAPI_LIVEPATCH_H
+#define _UAPI_LIVEPATCH_H
+
+#include <linux/types.h>
+
+#define KLP_RELA_PREFIX		".klp.rela."
+#define KLP_SYM_PREFIX		".klp.sym."
+
+#endif /* _UAPI_LIVEPATCH_H */
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index b9628e43c78f..a9b172d2c83f 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -212,7 +212,7 @@ static int klp_resolve_symbols(Elf_Shdr *relasec, struct module *pmod)
 
 		/* Format: .klp.sym.objname.symname,sympos */
 		cnt = sscanf(strtab + sym->st_name,
-			     ".klp.sym.%55[^.].%127[^,],%lu",
+			     KLP_SYM_PREFIX "%55[^.].%127[^,],%lu",
 			     objname, symname, &sympos);
 		if (cnt != 3) {
 			pr_err("symbol %s has an incorrectly formatted name\n",
@@ -258,7 +258,7 @@ static int klp_write_object_relocations(struct module *pmod,
 		 * See comment in klp_resolve_symbols() for an explanation
 		 * of the selected field width value.
 		 */
-		cnt = sscanf(secname, ".klp.rela.%55[^.]", sec_objname);
+		cnt = sscanf(secname, KLP_RELA_PREFIX "%55[^.]", sec_objname);
 		if (cnt != 1) {
 			pr_err("section %s has an incorrectly formatted name\n",
 			       secname);
-- 
2.12.0