Re: [PATCH v3 10/15] livepatch: move patching functions into patch.c

[Kamalesh Babulal]

On Thursday 08 December 2016 11:38 PM, Josh Poimboeuf wrote:

Move functions related to the actual patching of functions and objects
into a new patch.c file.

Signed-off-by: Josh Poimboeuf 


Reviewed-by: Kamalesh Babulal 

--
cheers,
Kamalesh.

Re: [PATCH v3 10/15] livepatch: move patching functions into patch.c

[Miroslav Benes]

On Thu, 8 Dec 2016, Josh Poimboeuf wrote:

> Move functions related to the actual patching of functions and objects
> into a new patch.c file.
> 
> Signed-off-by: Josh Poimboeuf 

Acked-by: Miroslav Benes 

Miroslav

Re: [PATCH v3 10/15] livepatch: move patching functions into patch.c

[Petr Mladek]

On Thu 2016-12-08 12:08:35, Josh Poimboeuf wrote:
> Move functions related to the actual patching of functions and objects
> into a new patch.c file.
> 
> Signed-off-by: Josh Poimboeuf 

Looks fine.

Reviewed-by: Petr Mladek 

Best Regards,
Petr

[PATCH v3 10/15] livepatch: move patching functions into patch.c

[Josh Poimboeuf]

Move functions related to the actual patching of functions and objects
into a new patch.c file.

Signed-off-by: Josh Poimboeuf 
---
 kernel/livepatch/Makefile |   2 +-
 kernel/livepatch/core.c   | 202 +--
 kernel/livepatch/patch.c  | 213 ++
 kernel/livepatch/patch.h  |  32 +++
 4 files changed, 247 insertions(+), 202 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 47ed643..6a137e1 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -24,32 +24,13 @@
 #include 
 #include 
 #include 
-#include 
 #include 
 #include 
 #include 
 #include 
 #include 
 #include 
-
-/**
- * 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
@@ -60,28 +41,12 @@ struct klp_ops {
 static DEFINE_MUTEX(klp_mutex);
 
 static LIST_HEAD(klp_patches);
-static LIST_HEAD(klp_ops);
 
 static struct kobject *klp_root_kobj;
 
 /* TODO: temporary stub */
 void klp_update_patch_state(struct task_struct *task) {}
 
-static struct klp_ops *klp_find_ops(unsigned long old_addr)
-{
-   struct klp_ops *ops;
-   struct klp_func *func;
-
-   list_for_each_entry(ops, _ops, node) {
-   func = list_first_entry(>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;
@@ -314,171 +279,6 @@ static int klp_write_object_relocations(struct module 
*pmod,
return ret;
 }
 
-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(>func_stack, struct klp_func,
- stack_node);
-   if (WARN_ON_ONCE(!func))
-   goto unlock;
-
-   klp_arch_set_pc(regs, (unsigned long)func->new_func);
-unlock:
-   rcu_read_unlock();
-}
-
-/*
- * Convert a function address into the appropriate ftrace location.
- *
- * Usually this is just the address of the function, but on some architectures
- * it's more complicated so allow them to provide a custom behaviour.
- */
-#ifndef klp_get_ftrace_location
-static unsigned long klp_get_ftrace_location(unsigned long faddr)
-{
-   return faddr;
-}
-#endif
-
-static void klp_unpatch_func(struct klp_func *func)
-{
-   struct klp_ops *ops;
-
-   if (WARN_ON(!func->patched))
-   return;
-   if (WARN_ON(!func->old_addr))
-   return;
-
-   ops = klp_find_ops(func->old_addr);
-   if (WARN_ON(!ops))
-   return;
-
-   if (list_is_singular(>func_stack)) {
-   unsigned long ftrace_loc;
-
-   ftrace_loc = klp_get_ftrace_location(func->old_addr);
-   if (WARN_ON(!ftrace_loc))
-   return;
-
-   WARN_ON(unregister_ftrace_function(>fops));
-   WARN_ON(ftrace_set_filter_ip(>fops, ftrace_loc, 1, 0));
-
-   list_del_rcu(>stack_node);
-   list_del(>node);
-   kfree(ops);
-   } else {
-   list_del_rcu(>stack_node);
-   }
-
-   func->patched = false;
-}
-
-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;
-
-