On Sun, Aug 21, 2011 at 6:16 PM, Al Viro <v...@zeniv.linux.org.uk> wrote:
>
> Is that ability a part of userland ABI or are we declaring that hopelessly
> wrong and require to go through the function in vdso32?  Linus?

If people are using syscall directly, we're pretty much stuck. No
amount of "that's hopelessly wrong" will ever matter. We don't break
existing binaries.

That said, I'd *hope* that everybody uses the vdso32, simply because
user programs are not supposed to know which CPU they are running on
and if that CPU even *supports* the syscall instruction. In which case
it may be possible that we can play games with the vdso thing. But
that really would be conditional on "nobody ever reports a failure".

But if that's possible, maybe we can increment the RIP by 2 for
'syscall', and slip an "'int 0x80" after the syscall instruction in
the vdso there? Resulting in the same pseudo-solution I suggested for
sysenter...

                          Linus

------------------------------------------------------------------------------
uberSVN's rich system and user administration capabilities and model 
configuration take the hassle out of deploying and managing Subversion and 
the tools developers use with it. Learn more about uberSVN and get a free 
download at:  http://p.sf.net/sfu/wandisco-dev2dev
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

Reply via email to