On Tue, Apr 05, 2022 at 12:01:19PM +0200, Ard Biesheuvel wrote: > On Tue, 5 Apr 2022 at 11:54, Greg Kroah-Hartman > <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > > From: Ard Biesheuvel <ardb@xxxxxxxxxx> > > > > [ Upstream commit d11967870815b5ab89843980e35aab616c97c463 ] > > > > Tweak the ftrace return paths to avoid redundant loads of SP, as well as > > unnecessary clobbering of IP. > > > > This also fixes the inconsistency of using MOV to perform a function > > return, which is sub-optimal on recent micro-architectures but more > > importantly, does not perform an interworking return, unlike compiler > > generated function returns in Thumb2 builds. > > > > Let's fix this by popping PC from the stack like most ordinary code > > does. > > > > Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> > > Reviewed-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> > > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > > Please drop all the 32-bit ARM patches authored by me from the stable > queues except the ones that have fixes tags. These are highly likely > to cause an explosion of regressions, and they should have never been > selected, as I don't remember anyone proposing these for stable.
