linux-kernel - Re: [PATCH v5 4/7] powerpc/qspinlock: Add ARCH_USE_QUEUED_SPINLOCKS

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 for Android: free password hash cracker in your pocket

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

Date:   Sun, 28 Mar 2021 19:36:47 +0800
From:   Guo Ren <guoren@...nel.org>
To:     Christophe Leroy <christophe.leroy@...roup.eu>
Cc:     linux-arch <linux-arch@...r.kernel.org>,
        linux-xtensa@...ux-xtensa.org, Guo Ren <guoren@...ux.alibaba.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-csky@...r.kernel.org, openrisc@...ts.librecores.org,
        Paul Mackerras <paulus@...ba.org>,
        sparclinux <sparclinux@...r.kernel.org>,
        linux-riscv <linux-riscv@...ts.infradead.org>,
        linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v5 4/7] powerpc/qspinlock: Add ARCH_USE_QUEUED_SPINLOCKS_XCHG32

On Sun, Mar 28, 2021 at 7:14 PM Christophe Leroy
<christophe.leroy@...roup.eu> wrote:
>
>
>
> Le 28/03/2021 à 08:30, guoren@...nel.org a écrit :
> > From: Guo Ren <guoren@...ux.alibaba.com>
> >
> > We don't have native hw xchg16 instruction, so let qspinlock
> > generic code to deal with it.
>
> We have lharx/sthcx pair on some versions of powerpc.
>
> See https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20201107032328.2454582-1-npiggin@gmail.com/
Got it, thx for the information.

>
> Christophe
>
> >
> > Using the full-word atomic xchg instructions implement xchg16 has
> > the semantic risk for atomic operations.
> >
> > This patch cancels the dependency of on qspinlock generic code on
> > architecture's xchg16.
> >
> > Signed-off-by: Guo Ren <guoren@...ux.alibaba.com>
> > Cc: Michael Ellerman <mpe@...erman.id.au>
> > Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
> > Cc: Paul Mackerras <paulus@...ba.org>
> > ---
> >   arch/powerpc/Kconfig | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> > index 386ae12d8523..69ec4ade6521 100644
> > --- a/arch/powerpc/Kconfig
> > +++ b/arch/powerpc/Kconfig
> > @@ -151,6 +151,7 @@ config PPC
> >       select ARCH_USE_CMPXCHG_LOCKREF         if PPC64
> >       select ARCH_USE_QUEUED_RWLOCKS          if PPC_QUEUED_SPINLOCKS
> >       select ARCH_USE_QUEUED_SPINLOCKS        if PPC_QUEUED_SPINLOCKS
> > +     select ARCH_USE_QUEUED_SPINLOCKS_XCHG32 if PPC_QUEUED_SPINLOCKS
> >       select ARCH_WANT_IPC_PARSE_VERSION
> >       select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
> >       select ARCH_WANT_LD_ORPHAN_WARN
> >



-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/