Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit a48c7709 authored by Petr Mladek's avatar Petr Mladek Committed by Jiri Kosina
Browse files

livepatch: Remove not longer valid limitations from the documentation 



Semantic changes are possible since the commit d83a7cb3
("livepatch: change to a per-task consistency model").

Also data structures can be patched since the commit 439e7271
("livepatch: introduce shadow variable API").

It is a high time we removed these limitations from the documentation.

Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
Acked-by: default avatarMiroslav Benes <mbenes@suse.cz>
Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent 41e3bef5

Documentation/livepatch/livepatch.txt

+0 −24
Original line number Diff line number Diff line
@@ -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