diff options
Diffstat (limited to 'kernel/livepatch/core.c')
-rw-r--r-- | kernel/livepatch/core.c | 202 |
1 files changed, 1 insertions, 201 deletions
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 47ed643a6362..6a137e1f4490 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -24,32 +24,13 @@ #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> #include <linux/elf.h> #include <linux/moduleloader.h> #include <asm/cacheflush.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 @@ -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, &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; @@ -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(&ops->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(&ops->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(&ops->fops)); - WARN_ON(ftrace_set_filter_ip(&ops->fops, ftrace_loc, 1, 0)); - - list_del_rcu(&func->stack_node); - list_del(&ops->node); - kfree(ops); - } else { - list_del_rcu(&func->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; - - ops = klp_find_ops(func->old_addr); - if (!ops) { - unsigned long ftrace_loc; - - ftrace_loc = klp_get_ftrace_location(func->old_addr); - if (!ftrace_loc) { - pr_err("failed to find location for function '%s'\n", - func->old_name); - return -EINVAL; - } - - 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, ftrace_loc, 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, ftrace_loc, 1, 0); - goto err; - } - - - } else { - list_add_rcu(&func->stack_node, &ops->func_stack); - } - - func->patched = true; - - 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; - - klp_for_each_func(obj, func) - if (func->patched) - klp_unpatch_func(func); - - obj->patched = false; -} - -static int klp_patch_object(struct klp_object *obj) -{ - struct klp_func *func; - int ret; - - if (WARN_ON(obj->patched)) - return -EINVAL; - - klp_for_each_func(obj, func) { - ret = klp_patch_func(func); - if (ret) { - klp_unpatch_object(obj); - return ret; - } - } - obj->patched = true; - - return 0; -} - static int __klp_disable_patch(struct klp_patch *patch) { struct klp_object *obj; |