linux-kernel - [PATCH v3 1/3] livepatch: use arch_klp_init_object

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Date:	Wed, 17 Aug 2016 20:58:28 -0400
From:	Jessica Yu <jeyu@...hat.com>
To:	Josh Poimboeuf <jpoimboe@...hat.com>,
	Miroslav Benes <mbenes@...e.cz>,
	Petr Mladek <pmladek@...e.com>, Jiri Kosina <jikos@...nel.org>,
	Chris J Arges <chris.j.arges@...onical.com>,
	Eugene Shatokhin <eugene.shatokhin@...alab.ru>
Cc:	live-patching@...r.kernel.org, x86@...nel.org,
	linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
	Jessica Yu <jeyu@...hat.com>
Subject: [PATCH v3 1/3] livepatch: use arch_klp_init_object_loaded() to finish arch-specific tasks

Introduce arch_klp_init_object_loaded() to complete any additional
arch-specific tasks during patching. Architecture code may override this
function.

Signed-off-by: Jessica Yu <jeyu@...hat.com>
---
 include/linux/livepatch.h |  3 +++
 kernel/livepatch/core.c   | 16 +++++++++++++---
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
index a93a0b2..9072f04 100644
--- a/include/linux/livepatch.h
+++ b/include/linux/livepatch.h
@@ -116,6 +116,9 @@ int klp_unregister_patch(struct klp_patch *);
 int klp_enable_patch(struct klp_patch *);
 int klp_disable_patch(struct klp_patch *);
 
+void arch_klp_init_object_loaded(struct klp_patch *patch,
+				 struct klp_object *obj);
+
 /* Called from the module loader during module coming/going states */
 int klp_module_coming(struct module *mod);
 void klp_module_going(struct module *mod);
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 8bbe507..5fbabe0 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -274,7 +274,6 @@ static int klp_write_object_relocations(struct module *pmod,
 
 	objname = klp_is_module(obj) ? obj->name : "vmlinux";
 
-	module_disable_ro(pmod);
 	/* For each klp relocation section */
 	for (i = 1; i < pmod->klp_info->hdr.e_shnum; i++) {
 		sec = pmod->klp_info->sechdrs + i;
@@ -309,7 +308,6 @@ static int klp_write_object_relocations(struct module *pmod,
 			break;
 	}
 
-	module_enable_ro(pmod, true);
 	return ret;
 }
 
@@ -763,6 +761,12 @@ static int klp_init_func(struct klp_object *obj, struct klp_func *func)
 				    func->old_sympos ? func->old_sympos : 1);
 }
 
+/* Arches may override this to finish any remaining arch-specific tasks */
+void __weak arch_klp_init_object_loaded(struct klp_patch *patch,
+					struct klp_object *obj)
+{
+}
+
 /* parts of the initialization that is done only when the object is loaded */
 static int klp_init_object_loaded(struct klp_patch *patch,
 				  struct klp_object *obj)
@@ -770,9 +774,15 @@ static int klp_init_object_loaded(struct klp_patch *patch,
 	struct klp_func *func;
 	int ret;
 
+	module_disable_ro(patch->mod);
 	ret = klp_write_object_relocations(patch->mod, obj);
-	if (ret)
+	if (ret) {
+		module_enable_ro(patch->mod, true);
 		return ret;
+	}
+
+	arch_klp_init_object_loaded(patch, obj);
+	module_enable_ro(patch->mod, true);
 
 	klp_for_each_func(obj, func) {
 		ret = klp_find_object_symbol(obj->name, func->old_name,
-- 
2.5.5