From: Petr Mladek Date: Wed, 23 May 2018 07:47:42 +0000 (+0200) Subject: livepatch: Remove not longer valid limitations from the documentation X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=a48c7709fe42712e86d2d68e1c9c4d2ce14c6a16;p=openwrt%2Fstaging%2Fblogic.git livepatch: Remove not longer valid limitations from the documentation Semantic changes are possible since the commit d83a7cb375eec21f04 ("livepatch: change to a per-task consistency model"). Also data structures can be patched since the commit 439e7271dc2b63de37 ("livepatch: introduce shadow variable API"). It is a high time we removed these limitations from the documentation. Signed-off-by: Petr Mladek Acked-by: Miroslav Benes Acked-by: Josh Poimboeuf Signed-off-by: Jiri Kosina --- diff --git a/Documentation/livepatch/livepatch.txt b/Documentation/livepatch/livepatch.txt index 1ae2de758c08..2d7ed09dbd59 100644 --- a/Documentation/livepatch/livepatch.txt +++ b/Documentation/livepatch/livepatch.txt @@ -429,30 +429,6 @@ See Documentation/ABI/testing/sysfs-kernel-livepatch for more details. The current Livepatch implementation has several limitations: - - + The patch must not change the semantic of the patched functions. - - The current implementation guarantees only that either the old - or the new function is called. The functions are patched one - by one. It means that the patch must _not_ change the semantic - of the function. - - - + Data structures can not be patched. - - There is no support to version data structures or anyhow migrate - one structure into another. Also the simple consistency model does - not allow to switch more functions atomically. - - Once there is more complex consistency mode, it will be possible to - use some workarounds. For example, it will be possible to use a hole - for a new member because the data structure is aligned. Or it will - be possible to use an existing member for something else. - - There are no plans to add more generic support for modified structures - at the moment. - - + Only functions that can be traced could be patched. Livepatch is based on the dynamic ftrace. In particular, functions