On Wed, Aug 16, 2017 at 03:17:04PM -0400, Joe Lawrence wrote: > Provide livepatch modules a klp_object (un)patching notification > mechanism. Pre and post-(un)patch callbacks allow livepatch modules to > setup or synchronize changes that would be difficult to support in only > patched-or-unpatched code contexts. > > Callbacks can be registered for target module or vmlinux klp_objects, > but each implementation is klp_object specific. > > - Pre-(un)patch callbacks run before any (un)patching action takes > place. > > - Post-(un)patch callbacks run once an object has been (un)patched and > the klp_patch fully transitioned to its target state. > > Example use cases include modification of global data and registration > of newly available services/handlers. > > See Documentation/livepatch/callback.txt for details. > > Signed-off-by: Joe Lawrence <[email protected]> > --- > Documentation/livepatch/callbacks.txt | 87 ++++++++++++ > include/linux/livepatch.h | 81 ++++++++++++ > kernel/livepatch/core.c | 37 ++++-- > kernel/livepatch/patch.c | 5 +- > kernel/livepatch/transition.c | 21 ++- > samples/livepatch/Makefile | 2 + > samples/livepatch/livepatch-callbacks-demo.c | 190 > +++++++++++++++++++++++++++ > samples/livepatch/livepatch-callbacks-mod.c | 53 ++++++++ > 8 files changed, 462 insertions(+), 14 deletions(-) > create mode 100644 Documentation/livepatch/callbacks.txt > create mode 100644 samples/livepatch/livepatch-callbacks-demo.c > create mode 100644 samples/livepatch/livepatch-callbacks-mod.c > > diff --git a/Documentation/livepatch/callbacks.txt > b/Documentation/livepatch/callbacks.txt > new file mode 100644 > index 000000000000..e18f2678f3bb > --- /dev/null > +++ b/Documentation/livepatch/callbacks.txt > @@ -0,0 +1,87 @@ > +(Un)patching Callbacks > +====================== > + > +Livepatch (un)patch-callbacks provide a mechanism for livepatch modules > +to execute callback functions when a kernel object is (un)patched. They > +can be considered a "power feature" that extends livepatching abilities > +to include: > + > + - Safe updates to global data > + > + - "Patches" to init and probe functions > + > + - Patching otherwise unpatchable code (i.e. assembly) > + > +In most cases, (un)patch hooks will need to be used in conjunction with
s/hooks/callbacks/ (though I wouldn't be opposed to changing them back to "hooks" anyway as it's one fewer syllable :-) but no strong opinion either way on that) -- Josh
