Commit Graph

4 Commits

Author SHA1 Message Date
Mark Brown 7af6fbddbd Documentation: livepatch: Convert to automatically generated contents
Automatically generate the tables of contents for livepatch documentation
files that have tables of contents rather than open coding them so things
are a little easier to maintain.

Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2021-01-26 11:50:00 +01:00
Peter Zijlstra 1d05334d28 livepatch: Remove .klp.arch
After the previous patch, vmlinux-specific KLP relocations are now
applied early during KLP module load.  This means that .klp.arch
sections are no longer needed for *vmlinux-specific* KLP relocations.

One might think they're still needed for *module-specific* KLP
relocations.  If a to-be-patched module is loaded *after* its
corresponding KLP module is loaded, any corresponding KLP relocations
will be delayed until the to-be-patched module is loaded.  If any
special sections (.parainstructions, for example) rely on those
relocations, their initializations (apply_paravirt) need to be done
afterwards.  Thus the apparent need for arch_klp_init_object_loaded()
and its corresponding .klp.arch sections -- it allows some of the
special section initializations to be done at a later time.

But... if you look closer, that dependency between the special sections
and the module-specific KLP relocations doesn't actually exist in
reality.  Looking at the contents of the .altinstructions and
.parainstructions sections, there's not a realistic scenario in which a
KLP module's .altinstructions or .parainstructions section needs to
access a symbol in a to-be-patched module.  It might need to access a
local symbol or even a vmlinux symbol; but not another module's symbol.
When a special section needs to reference a local or vmlinux symbol, a
normal rela can be used instead of a KLP rela.

Since the special section initializations don't actually have any real
dependency on module-specific KLP relocations, .klp.arch and
arch_klp_init_object_loaded() no longer have a reason to exist.  So
remove them.

As Peter said much more succinctly:

  So the reason for .klp.arch was that .klp.rela.* stuff would overwrite
  paravirt instructions. If that happens you're doing it wrong. Those
  RELAs are core kernel, not module, and thus should've happened in
  .rela.* sections at patch-module loading time.

  Reverting this removes the two apply_{paravirt,alternatives}() calls
  from the late patching path, and means we don't have to worry about
  them when removing module_disable_ro().

[ jpoimboe: Rewrote patch description.  Tweaked klp_init_object_loaded()
	    error path. ]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-05-08 00:12:42 +02:00
Petr Mladek d9defe448f docs/livepatch: Unify style of livepatch documentation in the ReST format
Make the structure of "Livepatch module Elf format" document similar
to the main "Livepatch" document.

Also make the structure of "(Un)patching Callbacks" document similar
to the "Shadow Variables" document.

It fixes the most visible inconsistencies of the documentation
generated from the ReST format.

Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-05-07 16:06:28 -06:00
Mauro Carvalho Chehab 89e33ea732 docs: livepatch: convert docs to ReST and rename to *.rst
Convert livepatch documentation to ReST format. The changes
are mostly trivial, as the documents are already on a good
shape. Just a few markup changes are needed for Sphinx to
properly parse the docs.

The conversion is actually:
  - add blank lines and identation in order to identify paragraphs;
  - fix tables markups;
  - add some lists markups;
  - mark literal blocks;
  - The in-file TOC becomes a comment, in order to skip it from the
    output, as Sphinx already generates an index there.
  - adjust title markups.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-05-07 16:05:49 -06:00