Re: Update NEWS for MPX support in the dynamic linker

[Markus Trippelsdorf <markus at trippelsdorf dot de>]

On 2014.08.08 at 09:44 -0700, Roland McGrath wrote:
> > @@ -24,6 +24,12 @@ Version 2.20
> >    17050, 17058, 17061, 17062, 17069, 17075, 17078, 17079, 17084, 17086,
> >    17088, 17092, 17097, 17125, 17135, 17137, 17150, 17153, 17213.
> > +* Support for Intel MPX in x86 dynamic linker was added. This means Intel MPX
> > +  bound registers are now saving/restoring in _dl_runtime_profile and
> > +  _dl_runtime_resolve. The change revealed "Unrecognised instruction" issue
> > +  in valgrind. It is known to be fixed in version 3.9 but still could be seen
> > +  in older versions of valgrind and probably in other similar tools.
> 
> You need a blank line before the new item.  Two spaces between sentences.
> Don't mention dynamic linker internal function names, just the user-visible
> effects.  How about this?
> 
> * On x86, the dynamic linker's lazy-binding support is now compatible
>   with application code using Intel MPX instructions.  (With all
>   previous versions, the MPX register state could be clobbered when
>   making calls into or out of a shared library.)  Note that while the
>   new dynamic linker is compatible with all known x86 hardware whether
>   or not it supports Intel MPX, some x86 instruction-set emulators
>   might fail to handle the new instruction encodings.  This is known
>   to affect Valgrind versions prior to 3.9, and might affect other
>   tools that do instruction emulation.

Please note that this issue is _not_ fixed in 3.9. There is no official
valgrind release with the fix available at the moment.

-- 
Markus