linux-kernel - Re: [PATCH cmpxchg 13/14] xtensa: Emulate one-byte cmpxchg

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Thu, 18 Apr 2024 16:21:46 -0700
From: "Paul E. McKenney" <paulmck@...nel.org>
To: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
	elver@...gle.com, akpm@...ux-foundation.org, tglx@...utronix.de,
	peterz@...radead.org, dianders@...omium.org, pmladek@...e.com,
	torvalds@...ux-foundation.org, Arnd Bergmann <arnd@...db.de>,
	Yujie Liu <yujie.liu@...el.com>,
	Andi Shyti <andi.shyti@...ux.intel.com>
Subject: Re: [PATCH cmpxchg 13/14] xtensa: Emulate one-byte cmpxchg

On Thu, Apr 18, 2024 at 10:06:21AM +0200, Geert Uytterhoeven wrote:
> Hi Paul,
> 
> On Mon, Apr 8, 2024 at 7:49 PM Paul E. McKenney <paulmck@...nel.org> wrote:
> > Use the new cmpxchg_emu_u8() to emulate one-byte cmpxchg() on xtensa.
> >
> > [ paulmck: Apply kernel test robot feedback. ]
> > [ paulmck: Drop two-byte support per Arnd Bergmann feedback. ]
> >
> > Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
> 
> Thanks for your patch!
> 
> > --- a/arch/xtensa/include/asm/cmpxchg.h
> > +++ b/arch/xtensa/include/asm/cmpxchg.h
> > @@ -74,6 +75,7 @@ static __inline__ unsigned long
> >  __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
> >  {
> >         switch (size) {
> > +       case 1:  return cmpxchg_emu_u8((volatile u8 *)ptr, old, new);
> 
> The cast is not needed.

In both cases, kernel test robot yelled at me when it was not present.

Happy to resubmit without it, though, if that is a yell that I should
have ignored.

							Thanx, Paul

> >         case 4:  return __cmpxchg_u32(ptr, old, new);
> >         default: __cmpxchg_called_with_bad_pointer();
> >                  return old;
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> -- 
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds