Re: [PATCH v7 03/14] x86/cet/ibt: Add IBT legacy code bitmap setup function
From: Yu-cheng Yu
Date: Mon Jun 10 2019 - 12:15:35 EST
On Fri, 2019-06-07 at 15:27 -0700, Andy Lutomirski wrote:
> > On Jun 7, 2019, at 2:09 PM, Dave Hansen <dave.hansen@xxxxxxxxx> wrote:
> > On 6/7/19 1:06 PM, Yu-cheng Yu wrote:
> > > > Huh, how does glibc know about all possible past and future legacy code
> > > > in the application?
> > >
> > > When dlopen() gets a legacy binary and the policy allows that, it will
> > > manage
> > > the bitmap:
> > >
> > > If a bitmap has not been created, create one.
> > > Set bits for the legacy code being loaded.
> > I was thinking about code that doesn't go through GLIBC like JITs.
> CRIU is another consideration: it would be rather annoying if CET programs
> canât migrate between LA57 and normal machines.
When a machine migrates, does its applications' addresses change?
If no, then the bitmap should still work, right?