From 444f9e99a840c4050c0530cfef81801a21a59f4c Mon Sep 17 00:00:00 2001 From: Chris J Arges Date: Tue, 1 Dec 2015 20:40:56 -0600 Subject: [PATCH] livepatch: function,sympos scheme in livepatch sysfs directory The following directory structure will allow for cases when the same function name exists in a single object. /sys/kernel/livepatch/// The sympos number corresponds to the nth occurrence of the symbol name in kallsyms for the patched object. An example of patching multiple symbols can be found here: https://github.com/dynup/kpatch/issues/493 Signed-off-by: Chris J Arges Reviewed-by: Petr Mladek Acked-by: Josh Poimboeuf Signed-off-by: Jiri Kosina --- Documentation/ABI/testing/sysfs-kernel-livepatch | 6 +++++- kernel/livepatch/core.c | 10 ++++++++-- 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-kernel-livepatch b/Documentation/ABI/testing/sysfs-kernel-livepatch index 5bf42a840b22..da87f43aec58 100644 --- a/Documentation/ABI/testing/sysfs-kernel-livepatch +++ b/Documentation/ABI/testing/sysfs-kernel-livepatch @@ -33,7 +33,7 @@ Description: The object directory contains subdirectories for each function that is patched within the object. -What: /sys/kernel/livepatch/// +What: /sys/kernel/livepatch/// Date: Nov 2014 KernelVersion: 3.19.0 Contact: live-patching@vger.kernel.org @@ -41,4 +41,8 @@ Description: The function directory contains attributes regarding the properties and state of the patched function. + The directory name contains the patched function name and a + sympos number corresponding to the nth occurrence of the symbol + name in kallsyms for the patched object. + There are currently no such attributes. diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index e842534d3493..94893e844e44 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -535,7 +535,7 @@ EXPORT_SYMBOL_GPL(klp_enable_patch); * /sys/kernel/livepatch/ * /sys/kernel/livepatch//enabled * /sys/kernel/livepatch// - * /sys/kernel/livepatch/// + * /sys/kernel/livepatch/// */ static ssize_t enabled_store(struct kobject *kobj, struct kobj_attribute *attr, @@ -680,8 +680,14 @@ static int klp_init_func(struct klp_object *obj, struct klp_func *func) INIT_LIST_HEAD(&func->stack_node); func->state = KLP_DISABLED; + /* The format for the sysfs directory is where sympos + * is the nth occurrence of this symbol in kallsyms for the patched + * object. If the user selects 0 for old_sympos, then 1 will be used + * since a unique symbol will be the first occurrence. + */ return kobject_init_and_add(&func->kobj, &klp_ktype_func, - &obj->kobj, "%s", func->old_name); + &obj->kobj, "%s,%lu", func->old_name, + func->old_sympos ? func->old_sympos : 1); } /* parts of the initialization that is done only when the object is loaded */ -- 2.20.1