lkml.org 
[lkml]   [2021]   [Jan]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 3/3] objtool: Support stack layout changes in alternatives
On Fri, Jan 08, 2021 at 09:15:43AM +0100, Miroslav Benes wrote:
> > That comment is indeed now obsolete. I can squash something like so:
> >
> > diff --git a/tools/objtool/check.c b/tools/objtool/check.c
> > index 81d56fdef1c3..ce67437aaf3f 100644
> > --- a/tools/objtool/check.c
> > +++ b/tools/objtool/check.c
> > @@ -958,21 +958,8 @@ static int add_call_destinations(struct objtool_file *file)
> > }
> >
> > /*
> > - * The .alternatives section requires some extra special care, over and above
> > - * what other special sections require:
> > - *
> > - * 1. Because alternatives are patched in-place, we need to insert a fake jump
> > - * instruction at the end so that validate_branch() skips all the original
> > - * replaced instructions when validating the new instruction path.
> > - *
> > - * 2. An added wrinkle is that the new instruction length might be zero. In
> > - * that case the old instructions are replaced with noops. We simulate that
> > - * by creating a fake jump as the only new instruction.
> > - *
> > - * 3. In some cases, the alternative section includes an instruction which
> > - * conditionally jumps to the _end_ of the entry. We have to modify these
> > - * jumps' destinations to point back to .text rather than the end of the
> > - * entry in .altinstr_replacement.
> > + * The .alternatives section requires some extra special care over and above
> > + * other special sections because alternatives are patched in place.
> > */
> > static int handle_group_alt(struct objtool_file *file,
> > struct special_alt *special_alt,
>
> Looks good to me.

Thanks, I squashed this in.

If there are no objections, I'll go ahead and merge this set in -tip.
It doesn't have any direct dependencies on the Juergen's changes, and it
would be nice to have some of these changes in-tree, especially the fake
jump removal.

--
Josh

\
 
 \ /
  Last update: 2021-01-14 01:30    [W:0.083 / U:0.120 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site