Re: [PATCH] x32: Switch back to assembly syscall wrapper for prctl

Alejandro Colomar <[email protected]> Sun, 7 Dec 2025 13:34:36 +0100

Newsgroups	org.kernel.vger.util-linux
Message-ID	<blmb25wi2xskdsfkkgsm25uzacnn3kjny3if2uaazwfivzsdlw@siix5jfad7yj>

Hi H.J.,

On Sun, Dec 07, 2025 at 11:52:08AM +0800, H.J. Lu wrote:
> On Thu, Dec 4, 2025 at 10:06 PM Adhemerval Zanella Netto
> <[email protected]> wrote:
> >
> > The x32 and or1k (which also uses similar implementation) does seems broken
> > without checking the 'option' argument to see which arg we can va_arg.
> >
> > The problem is adding this logic on libc will add some forward-compatibility
> > that we try to avoid (newer kernel prctl additions might now work correctly).
> >
> > I am not sure why we haven't switch x32 back to the assembly wrappers
> > with 6a04404521ac4119ae36827eeb288ea84eee7cf6 fix (BZ#29770).  H.J, can
> > use remove the x32 C version (and also or1k as well)?
> 
> Since the variadic prctl function takes at most 5 integer arguments which
> are passed in the same integer registers on x32 as the function with 5
> integer arguments, we can safely use assembly syscall wrapper for prctl
> for x32.
> 
> Tested on x32.  I leave or1k alone since I don't know if it is safe to
> do the same.

Thanks!  Would you mind adding the following tag?

	Reported-by: Alejandro Colomar <[email protected]>

Have a lovely day!
Alex

-- 
<https://www.alejandro-colomar.es>

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