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Message-Id: <35666b8f283baf00be64ece874913e7ec8b13256.1423499826.git.jpoimboe@redhat.com>
Date: Mon, 9 Feb 2015 11:31:15 -0600
From: Josh Poimboeuf <jpoimboe@...hat.com>
To: Seth Jennings <sjenning@...hat.com>, Jiri Kosina <jkosina@...e.cz>,
Vojtech Pavlik <vojtech@...e.cz>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
live-patching@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [RFC PATCH 3/9] livepatch: move patching functions into patch.c
Move functions related to the actual patching of functions and objects
into a new patch.c file.
The only functional change is to remove the unnecessary
WARN_ON(!klp_is_object_loaded()) check from klp_patch_object().
Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
---
kernel/livepatch/Makefile | 2 +-
kernel/livepatch/core.c | 175 +--------------------------------------------
kernel/livepatch/patch.c | 176 ++++++++++++++++++++++++++++++++++++++++++++++
kernel/livepatch/patch.h | 25 +++++++
4 files changed, 203 insertions(+), 175 deletions(-)
create mode 100644 kernel/livepatch/patch.c
create mode 100644 kernel/livepatch/patch.h
diff --git a/kernel/livepatch/Makefile b/kernel/livepatch/Makefile
index e8780c0..e136dad 100644
--- a/kernel/livepatch/Makefile
+++ b/kernel/livepatch/Makefile
@@ -1,3 +1,3 @@
obj-$(CONFIG_LIVEPATCH) += livepatch.o
-livepatch-objs := core.o
+livepatch-objs := core.o patch.o
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 73f9ba4..0c09eba 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -24,29 +24,10 @@
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/slab.h>
-#include <linux/ftrace.h>
#include <linux/list.h>
#include <linux/kallsyms.h>
-#include <linux/livepatch.h>
-/**
- * struct klp_ops - structure for tracking registered ftrace ops structs
- *
- * A single ftrace_ops is shared between all enabled replacement functions
- * (klp_func structs) which have the same old_addr. This allows the switch
- * between function versions to happen instantaneously by updating the klp_ops
- * struct's func_stack list. The winner is the klp_func at the top of the
- * func_stack (front of the list).
- *
- * @node: node for the global klp_ops list
- * @func_stack: list head for the stack of klp_func's (active func is on top)
- * @fops: registered ftrace ops struct
- */
-struct klp_ops {
- struct list_head node;
- struct list_head func_stack;
- struct ftrace_ops fops;
-};
+#include "patch.h"
/*
* The klp_mutex protects the global lists and state transitions of any
@@ -57,25 +38,9 @@ struct klp_ops {
static DEFINE_MUTEX(klp_mutex);
static LIST_HEAD(klp_patches);
-static LIST_HEAD(klp_ops);
static struct kobject *klp_root_kobj;
-static struct klp_ops *klp_find_ops(unsigned long old_addr)
-{
- struct klp_ops *ops;
- struct klp_func *func;
-
- list_for_each_entry(ops, &klp_ops, node) {
- func = list_first_entry(&ops->func_stack, struct klp_func,
- stack_node);
- if (func->old_addr == old_addr)
- return ops;
- }
-
- return NULL;
-}
-
static bool klp_is_module(struct klp_object *obj)
{
return obj->name;
@@ -301,144 +266,6 @@ static int klp_write_object_relocations(struct module *pmod,
return 0;
}
-static void notrace klp_ftrace_handler(unsigned long ip,
- unsigned long parent_ip,
- struct ftrace_ops *fops,
- struct pt_regs *regs)
-{
- struct klp_ops *ops;
- struct klp_func *func;
-
- ops = container_of(fops, struct klp_ops, fops);
-
- rcu_read_lock();
- func = list_first_or_null_rcu(&ops->func_stack, struct klp_func,
- stack_node);
- rcu_read_unlock();
-
- if (WARN_ON_ONCE(!func))
- return;
-
- klp_arch_set_pc(regs, (unsigned long)func->new_func);
-}
-
-static void klp_unpatch_func(struct klp_func *func)
-{
- struct klp_ops *ops;
-
- WARN_ON(!func->patched);
- WARN_ON(!func->old_addr);
-
- ops = klp_find_ops(func->old_addr);
- if (WARN_ON(!ops))
- return;
-
- if (list_is_singular(&ops->func_stack)) {
- WARN_ON(unregister_ftrace_function(&ops->fops));
- WARN_ON(ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0));
-
- list_del_rcu(&func->stack_node);
- list_del(&ops->node);
- kfree(ops);
- } else {
- list_del_rcu(&func->stack_node);
- }
-
- func->patched = 0;
-}
-
-static int klp_patch_func(struct klp_func *func)
-{
- struct klp_ops *ops;
- int ret;
-
- if (WARN_ON(!func->old_addr))
- return -EINVAL;
-
- if (WARN_ON(func->patched))
- return -EINVAL;
-
- ops = klp_find_ops(func->old_addr);
- if (!ops) {
- ops = kzalloc(sizeof(*ops), GFP_KERNEL);
- if (!ops)
- return -ENOMEM;
-
- ops->fops.func = klp_ftrace_handler;
- ops->fops.flags = FTRACE_OPS_FL_SAVE_REGS |
- FTRACE_OPS_FL_DYNAMIC |
- FTRACE_OPS_FL_IPMODIFY;
-
- list_add(&ops->node, &klp_ops);
-
- INIT_LIST_HEAD(&ops->func_stack);
- list_add_rcu(&func->stack_node, &ops->func_stack);
-
- ret = ftrace_set_filter_ip(&ops->fops, func->old_addr, 0, 0);
- if (ret) {
- pr_err("failed to set ftrace filter for function '%s' (%d)\n",
- func->old_name, ret);
- goto err;
- }
-
- ret = register_ftrace_function(&ops->fops);
- if (ret) {
- pr_err("failed to register ftrace handler for function '%s' (%d)\n",
- func->old_name, ret);
- ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0);
- goto err;
- }
-
-
- } else {
- list_add_rcu(&func->stack_node, &ops->func_stack);
- }
-
- func->patched = 1;
-
- return 0;
-
-err:
- list_del_rcu(&func->stack_node);
- list_del(&ops->node);
- kfree(ops);
- return ret;
-}
-
-static void klp_unpatch_object(struct klp_object *obj)
-{
- struct klp_func *func;
-
- for (func = obj->funcs; func->old_name; func++)
- if (func->patched)
- klp_unpatch_func(func);
-
- obj->patched = 0;
-}
-
-static int klp_patch_object(struct klp_object *obj)
-{
- struct klp_func *func;
- int ret;
-
- if (WARN_ON(obj->patched))
- return -EINVAL;
-
- if (WARN_ON(!klp_is_object_loaded(obj)))
- return -EINVAL;
-
- for (func = obj->funcs; func->old_name; func++) {
- ret = klp_patch_func(func);
- if (ret) {
- klp_unpatch_object(obj);
- return ret;
- }
- }
- obj->patched = 1;
-
- return 0;
-}
-
static int __klp_disable_patch(struct klp_patch *patch)
{
struct klp_object *obj;
diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c
new file mode 100644
index 0000000..281fbca
--- /dev/null
+++ b/kernel/livepatch/patch.c
@@ -0,0 +1,176 @@
+/*
+ * patch.c - Kernel Live Patching patching functions
+ *
+ * Copyright (C) 2014 Seth Jennings <sjenning@...hat.com>
+ * Copyright (C) 2014 SUSE
+ * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@...hat.com>
+ *
+ * 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/>.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/slab.h>
+
+#include "patch.h"
+
+static LIST_HEAD(klp_ops);
+
+static void notrace klp_ftrace_handler(unsigned long ip,
+ unsigned long parent_ip,
+ struct ftrace_ops *fops,
+ struct pt_regs *regs)
+{
+ struct klp_ops *ops;
+ struct klp_func *func;
+
+ ops = container_of(fops, struct klp_ops, fops);
+
+ rcu_read_lock();
+ func = list_first_or_null_rcu(&ops->func_stack, struct klp_func,
+ stack_node);
+ rcu_read_unlock();
+
+ if (WARN_ON_ONCE(!func))
+ return;
+
+ klp_arch_set_pc(regs, (unsigned long)func->new_func);
+}
+
+struct klp_ops *klp_find_ops(unsigned long old_addr)
+{
+ struct klp_ops *ops;
+ struct klp_func *func;
+
+ list_for_each_entry(ops, &klp_ops, node) {
+ func = list_first_entry(&ops->func_stack, struct klp_func,
+ stack_node);
+ if (func->old_addr == old_addr)
+ return ops;
+ }
+
+ return NULL;
+}
+
+static void klp_unpatch_func(struct klp_func *func)
+{
+ struct klp_ops *ops;
+
+ WARN_ON(!func->patched);
+ WARN_ON(!func->old_addr);
+
+ ops = klp_find_ops(func->old_addr);
+ if (WARN_ON(!ops))
+ return;
+
+ if (list_is_singular(&ops->func_stack)) {
+ WARN_ON(unregister_ftrace_function(&ops->fops));
+ WARN_ON(ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0));
+
+ list_del_rcu(&func->stack_node);
+ list_del(&ops->node);
+ kfree(ops);
+ } else {
+ list_del_rcu(&func->stack_node);
+ }
+
+ func->patched = 0;
+}
+
+static int klp_patch_func(struct klp_func *func)
+{
+ struct klp_ops *ops;
+ int ret;
+
+ if (WARN_ON(!func->old_addr))
+ return -EINVAL;
+
+ if (WARN_ON(func->patched))
+ return -EINVAL;
+
+ ops = klp_find_ops(func->old_addr);
+ if (!ops) {
+ ops = kzalloc(sizeof(*ops), GFP_KERNEL);
+ if (!ops)
+ return -ENOMEM;
+
+ ops->fops.func = klp_ftrace_handler;
+ ops->fops.flags = FTRACE_OPS_FL_SAVE_REGS |
+ FTRACE_OPS_FL_DYNAMIC |
+ FTRACE_OPS_FL_IPMODIFY;
+
+ list_add(&ops->node, &klp_ops);
+
+ INIT_LIST_HEAD(&ops->func_stack);
+ list_add_rcu(&func->stack_node, &ops->func_stack);
+
+ ret = ftrace_set_filter_ip(&ops->fops, func->old_addr, 0, 0);
+ if (ret) {
+ pr_err("failed to set ftrace filter for function '%s' (%d)\n",
+ func->old_name, ret);
+ goto err;
+ }
+
+ ret = register_ftrace_function(&ops->fops);
+ if (ret) {
+ pr_err("failed to register ftrace handler for function '%s' (%d)\n",
+ func->old_name, ret);
+ ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0);
+ goto err;
+ }
+ } else {
+ list_add_rcu(&func->stack_node, &ops->func_stack);
+ }
+
+ func->patched = 1;
+
+ return 0;
+
+err:
+ list_del_rcu(&func->stack_node);
+ list_del(&ops->node);
+ kfree(ops);
+ return ret;
+}
+
+void klp_unpatch_object(struct klp_object *obj)
+{
+ struct klp_func *func;
+
+ for (func = obj->funcs; func->old_name; func++)
+ if (func->patched)
+ klp_unpatch_func(func);
+
+ obj->patched = 0;
+}
+
+int klp_patch_object(struct klp_object *obj)
+{
+ struct klp_func *func;
+ int ret;
+
+ if (WARN_ON(obj->patched))
+ return -EINVAL;
+
+ for (func = obj->funcs; func->old_name; func++) {
+ ret = klp_patch_func(func);
+ if (ret) {
+ klp_unpatch_object(obj);
+ return ret;
+ }
+ }
+ obj->patched = 1;
+
+ return 0;
+}
diff --git a/kernel/livepatch/patch.h b/kernel/livepatch/patch.h
new file mode 100644
index 0000000..bb34bd3
--- /dev/null
+++ b/kernel/livepatch/patch.h
@@ -0,0 +1,25 @@
+#include <linux/livepatch.h>
+
+/**
+ * struct klp_ops - structure for tracking registered ftrace ops structs
+ *
+ * A single ftrace_ops is shared between all enabled replacement functions
+ * (klp_func structs) which have the same old_addr. This allows the switch
+ * between function versions to happen instantaneously by updating the klp_ops
+ * struct's func_stack list. The winner is the klp_func at the top of the
+ * func_stack (front of the list).
+ *
+ * @node: node for the global klp_ops list
+ * @func_stack: list head for the stack of klp_func's (active func is on top)
+ * @fops: registered ftrace ops struct
+ */
+struct klp_ops {
+ struct list_head node;
+ struct list_head func_stack;
+ struct ftrace_ops fops;
+};
+
+struct klp_ops *klp_find_ops(unsigned long old_addr);
+
+extern int klp_patch_object(struct klp_object *obj);
+extern void klp_unpatch_object(struct klp_object *obj);
--
2.1.0
--
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