diff options
author | Petr Mladek <pmladek@suse.com> | 2018-05-23 03:47:42 -0400 |
---|---|---|
committer | Jiri Kosina <jkosina@suse.cz> | 2018-05-24 09:37:57 -0400 |
commit | a48c7709fe42712e86d2d68e1c9c4d2ce14c6a16 (patch) | |
tree | dee5ede0e4ef058f780a4f6429bee8a33b9b19b2 | |
parent | 41e3bef52e42c03cb7234f2d8419352478c92926 (diff) |
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 <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
-rw-r--r-- | Documentation/livepatch/livepatch.txt | 24 |
1 files changed, 0 insertions, 24 deletions
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. | |||
429 | 429 | ||
430 | The current Livepatch implementation has several limitations: | 430 | The current Livepatch implementation has several limitations: |
431 | 431 | ||
432 | |||
433 | + The patch must not change the semantic of the patched functions. | ||
434 | |||
435 | The current implementation guarantees only that either the old | ||
436 | or the new function is called. The functions are patched one | ||
437 | by one. It means that the patch must _not_ change the semantic | ||
438 | of the function. | ||
439 | |||
440 | |||
441 | + Data structures can not be patched. | ||
442 | |||
443 | There is no support to version data structures or anyhow migrate | ||
444 | one structure into another. Also the simple consistency model does | ||
445 | not allow to switch more functions atomically. | ||
446 | |||
447 | Once there is more complex consistency mode, it will be possible to | ||
448 | use some workarounds. For example, it will be possible to use a hole | ||
449 | for a new member because the data structure is aligned. Or it will | ||
450 | be possible to use an existing member for something else. | ||
451 | |||
452 | There are no plans to add more generic support for modified structures | ||
453 | at the moment. | ||
454 | |||
455 | |||
456 | + Only functions that can be traced could be patched. | 432 | + Only functions that can be traced could be patched. |
457 | 433 | ||
458 | Livepatch is based on the dynamic ftrace. In particular, functions | 434 | Livepatch is based on the dynamic ftrace. In particular, functions |