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SubjectRe: [PATCH 3/3 v4] livepatch: old_name,number scheme in livepatch sysfs directory
On Wed, Nov 11, 2015 at 10:29:01AM -0600, Chris J Arges wrote:
> The following directory structure will allow for cases when the same
> function name exists in a single object.
> /sys/kernel/livepatch/<patch>/<object>/<function,number>
>
> The 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

Instead of 'function,number' here and everywhere else, maybe
'function,sympos' would be a little clearer.

Also, s/old_name/function/ in the patch subject to be consistent.

> Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>
> ---
> 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 5bf42a8..21b6bc1 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/<patch>/<object>/<function>
> +What: /sys/kernel/livepatch/<patch>/<object>/<function,number>
> 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
> + 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 4eb8691..ed2cbbf 100644
> --- a/kernel/livepatch/core.c
> +++ b/kernel/livepatch/core.c
> @@ -542,7 +542,7 @@ EXPORT_SYMBOL_GPL(klp_enable_patch);
> * /sys/kernel/livepatch/<patch>
> * /sys/kernel/livepatch/<patch>/enabled
> * /sys/kernel/livepatch/<patch>/<object>
> - * /sys/kernel/livepatch/<patch>/<object>/<func>
> + * /sys/kernel/livepatch/<patch>/<object>/<func,number>
> */
>
> static ssize_t enabled_store(struct kobject *kobj, struct kobj_attribute *attr,
> @@ -687,8 +687,14 @@ 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 <func,number> where number is
> + * the occurrence of this symbol in kallsyms. If the user selects 0 for

... of this symbol in kallsyms *for the patched object*.

> + * 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 */
> --
> 1.9.1

--
Josh


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