diff options
Diffstat (limited to 'kernel/livepatch')
| -rw-r--r-- | kernel/livepatch/core.c | 34 |
1 files changed, 31 insertions, 3 deletions
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index bc2c85c064c1..35ee2c5b7176 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -298,6 +298,19 @@ 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_disable_func(struct klp_func *func) { struct klp_ops *ops; @@ -312,8 +325,14 @@ static void klp_disable_func(struct klp_func *func) 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, func->old_addr, 1, 0)); + WARN_ON(ftrace_set_filter_ip(&ops->fops, ftrace_loc, 1, 0)); list_del_rcu(&func->stack_node); list_del(&ops->node); @@ -338,6 +357,15 @@ static int klp_enable_func(struct klp_func *func) 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; @@ -352,7 +380,7 @@ static int klp_enable_func(struct klp_func *func) 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); + 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); @@ -363,7 +391,7 @@ static int klp_enable_func(struct klp_func *func) 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); + ftrace_set_filter_ip(&ops->fops, ftrace_loc, 1, 0); goto err; } |