Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:8 as permitted sender) client-ip=2620:137:e000::3:8;
MIME-Version: 1.0
References: <20231004145137.86537-1-ubizjak@gmail.com> <20231004145137.86537-5-ubizjak@gmail.com>
 <CAHk-=wgepFm=jGodFQYPAaEvcBhR3-f_h1BLBYiVQsutCwCnUQ@mail.gmail.com>
 <CAFULd4YWjxoSTyCtMN0OzKgHtshMQOuMH1Z0n_OaWKVnUjy2iA@mail.gmail.com>
 <CAHk-=whq=+LNHmsde8LaF4pdvKxqKt5GxW+Tq+U35_aDcV0ADg@mail.gmail.com>
 <CAHk-=wi6U-O1wdPOESuCE6QO2OaPu0hEzaig0uDOU4L5CREhug@mail.gmail.com>
 <CAFULd4Z3C771u8Y==8h6hi=mhGmy=7RJRAEBGfNZ0SmynxF41g@mail.gmail.com>
 <ZSPm6Z/lTK1ZlO8m@gmail.com> <ZSPpW3zLTn7IohOJ@gmail.com> <CAFULd4bjnro3CFQLY=qR0S5M0WY3NkrVUW-JUk4nB4mV7xhWNg@mail.gmail.com>
 <EEA95C45-87E6-4033-AEB2-0EC109220074@vmware.com>
In-Reply-To: <EEA95C45-87E6-4033-AEB2-0EC109220074@vmware.com>
From:   Uros Bizjak <ubizjak@gmail.com>
Date:   Mon, 9 Oct 2023 14:42:10 +0200
Message-ID: <CAFULd4aOSz0ZCtDdh=eST6DCr+ds2B9O2Rk0cyUeS+qQmWdOMA@mail.gmail.com>
Subject: Re: [PATCH 4/4] x86/percpu: Use C for percpu read/write accessors
To:     Nadav Amit <namit@vmware.com>
Cc:     Ingo Molnar <mingo@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        "the arch/x86 maintainers" <x86@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Andy Lutomirski <luto@kernel.org>,
        Brian Gerst <brgerst@gmail.com>,
        Denys Vlasenko <dvlasenk@redhat.com>,
        "H . Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Borislav Petkov <bp@alien8.de>,
        Josh Poimboeuf <jpoimboe@redhat.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Mon, Oct 9, 2023 at 2:21=E2=80=AFPM Nadav Amit <namit@vmware.com> wrote:
>
>
>
> > On Oct 9, 2023, at 3:00 PM, Uros Bizjak <ubizjak@gmail.com> wrote:
> >
> > !! External Email
> >
> > On Mon, Oct 9, 2023 at 1:51=E2=80=AFPM Ingo Molnar <mingo@kernel.org> w=
rote:
> >>
> >> BTW., while this OK for testing, this is too heavy handed for release
> >> purposes, so please only disable the KASAN instrumentation for the aff=
ected
> >> percpu accessors.
> >>
> >> See the various __no_sanitize* attributes available.
> >
> > These attributes are for function declarations. The percpu casts can
> > not be implemented with separate static inline functions. Also,
> > __no_sanitize_address is mutually exclusive with __always_inline.
>
> Right, but for GCC you may be able to do something like:
>
>     #pragma GCC diagnostic push
>     #pragma GCC diagnostic ignored "-fsanitize=3Daddress"
>
>     // Your code here...
>     #pragma GCC diagnostic pop
>
> Not sure if there is something equivalent in CLANG, and it should be done=
 with
> the kernel=E2=80=99s _Pragma.

Unfortunately, this is only for diagnostics and expects "-W..." to
suppress warnings. Here we want to disable kernel sanitizer just for
the enclosing access and I'm sure it won't work with diagnostics
pragmas. I don't think that "-fsanitize=3D..." is included in target or
optimization options allowed in Pragma.

Uros.