This feature can provide livepatch patch order information. With the order of sysfs interface of one klp_patch, we can use patch order to find out which function of the patch is now activate.
After the discussion, we decided that patch-level sysfs interface is the only accaptable way to introduce this information. This feature is like: cat /sys/kernel/livepatch/livepatch_1/order -> 1 means this livepatch_1 module is the 1st klp patch applied. cat /sys/kernel/livepatch/livepatch_module/order -> N means this lviepatch_module is the Nth klp patch applied to the system. Suggested-by: Petr Mladek <[email protected]> Suggested-by: Miroslav Benes <[email protected]> Suggested-by: Josh Poimboeuf <[email protected]> Signed-off-by: Wardenjohn <[email protected]> diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h index 51a258c24ff5..0fbbc1636ebe 100644 --- a/include/linux/livepatch.h +++ b/include/linux/livepatch.h @@ -154,6 +154,7 @@ struct klp_state { * @forced: was involved in a forced transition * @free_work: patch cleanup from workqueue-context * @finish: for waiting till it is safe to remove the patch module + * @order: the order of this patch applied to the system */ struct klp_patch { /* external */ @@ -170,6 +171,7 @@ struct klp_patch { bool forced; struct work_struct free_work; struct completion finish; + int order; }; #define klp_for_each_object_static(patch, obj) \ diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 3c21c31796db..024853aa43a8 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -347,6 +347,7 @@ int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs, * /sys/kernel/livepatch/<patch>/transition * /sys/kernel/livepatch/<patch>/force * /sys/kernel/livepatch/<patch>/replace + * /sys/kernel/livepatch/<patch>/order * /sys/kernel/livepatch/<patch>/<object> * /sys/kernel/livepatch/<patch>/<object>/patched * /sys/kernel/livepatch/<patch>/<object>/<function,sympos> @@ -452,15 +453,26 @@ static ssize_t replace_show(struct kobject *kobj, return sysfs_emit(buf, "%d\n", patch->replace); } +static ssize_t order_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + struct klp_patch *patch; + + patch = container_of(kobj, struct klp_patch, kobj); + return sysfs_emit(buf, "%d\n", patch->order); +} + static struct kobj_attribute enabled_kobj_attr = __ATTR_RW(enabled); static struct kobj_attribute transition_kobj_attr = __ATTR_RO(transition); static struct kobj_attribute force_kobj_attr = __ATTR_WO(force); static struct kobj_attribute replace_kobj_attr = __ATTR_RO(replace); +static struct kobj_attribute order_kobj_attr = __ATTR_RO(order); static struct attribute *klp_patch_attrs[] = { &enabled_kobj_attr.attr, &transition_kobj_attr.attr, &force_kobj_attr.attr, &replace_kobj_attr.attr, + &order_kobj_attr.attr, NULL }; ATTRIBUTE_GROUPS(klp_patch); diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c index ba069459c101..73bce68d22f8 100644 --- a/kernel/livepatch/transition.c +++ b/kernel/livepatch/transition.c @@ -46,6 +46,15 @@ EXPORT_SYMBOL(klp_sched_try_switch_key); #endif /* CONFIG_PREEMPT_DYNAMIC && CONFIG_HAVE_PREEMPT_DYNAMIC_CALL */ +static inline int klp_get_patch_order(struct klp_patch *patch) +{ + int order = 0; + + klp_for_each_patch(patch) + order = order + 1; + return order; +} + /* * This work can be performed periodically to finish patching or unpatching any * "straggler" tasks which failed to transition in the first attempt. @@ -591,6 +600,8 @@ void klp_init_transition(struct klp_patch *patch, int state) pr_debug("'%s': initializing %s transition\n", patch->mod->name, klp_target_state == KLP_TRANSITION_PATCHED ? "patching" : "unpatching"); + patch->order = klp_get_patch_order(patch); + /* * Initialize all tasks to the initial patch state to prepare them for * switching to the target state. -- 2.18.2
