From adb68ed26a3e92224e04502c768f1bb03b7c7aeb Mon Sep 17 00:00:00 2001 From: Yafang Shao Date: Tue, 25 Jun 2024 23:11:21 +0800 Subject: [PATCH] livepatch: Add "replace" sysfs attribute There are situations when it might make sense to combine livepatches with and without the atomic replace on the same system. For example, the livepatch without the atomic replace might provide a hotfix or extra tuning. Managing livepatches on such systems might be challenging. And the information which of the installed livepatches do not use the atomic replace would be useful. Add new sysfs interface 'replace'. It works as follows: $ cat /sys/kernel/livepatch/livepatch-non_replace/replace 0 $ cat /sys/kernel/livepatch/livepatch-replace/replace 1 [ commit log improved by Petr ] Signed-off-by: Yafang Shao Reviewed-by: Petr Mladek Acked-by: Miroslav Benes Link: https://lore.kernel.org/r/20240625151123.2750-2-laoar.shao@gmail.com Signed-off-by: Petr Mladek --- Documentation/ABI/testing/sysfs-kernel-livepatch | 8 ++++++++ kernel/livepatch/core.c | 12 ++++++++++++ 2 files changed, 20 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-kernel-livepatch b/Documentation/ABI/testing/sysfs-kernel-livepatch index a5df9b4910dc4..3735d868013d0 100644 --- a/Documentation/ABI/testing/sysfs-kernel-livepatch +++ b/Documentation/ABI/testing/sysfs-kernel-livepatch @@ -47,6 +47,14 @@ Description: disabled when the feature is used. See Documentation/livepatch/livepatch.rst for more information. +What: /sys/kernel/livepatch//replace +Date: Jun 2024 +KernelVersion: 6.11.0 +Contact: live-patching@vger.kernel.org +Description: + An attribute which indicates whether the patch supports + atomic-replace. + What: /sys/kernel/livepatch// Date: Nov 2014 KernelVersion: 3.19.0 diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 52426665eecc1..ad28617bfd75e 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -346,6 +346,7 @@ int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs, * /sys/kernel/livepatch//enabled * /sys/kernel/livepatch//transition * /sys/kernel/livepatch//force + * /sys/kernel/livepatch//replace * /sys/kernel/livepatch// * /sys/kernel/livepatch///patched * /sys/kernel/livepatch/// @@ -443,13 +444,24 @@ static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr, return count; } +static ssize_t replace_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->replace); +} + 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 attribute *klp_patch_attrs[] = { &enabled_kobj_attr.attr, &transition_kobj_attr.attr, &force_kobj_attr.attr, + &replace_kobj_attr.attr, NULL }; ATTRIBUTE_GROUPS(klp_patch); -- 2.39.5