From: Uros Bizjak <ubizjak@gmail.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Andy Lutomirski <luto@kernel.org>, Nadav Amit <namit@vmware.com>,
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>
Subject: Re: [PATCH 4/4] x86/percpu: Use C for percpu read/write accessors
Date: Mon, 9 Oct 2023 14:00:45 +0200 [thread overview]
Message-ID: <CAFULd4bjnro3CFQLY=qR0S5M0WY3NkrVUW-JUk4nB4mV7xhWNg@mail.gmail.com> (raw)
In-Reply-To: <ZSPpW3zLTn7IohOJ@gmail.com>
On Mon, Oct 9, 2023 at 1:51 PM Ingo Molnar <mingo@kernel.org> wrote:
>
>
> * Ingo Molnar <mingo@kernel.org> wrote:
>
> >
> > * Uros Bizjak <ubizjak@gmail.com> wrote:
> >
> > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > > index ecb256954351..1edf4a5b93ca 100644
> > > --- a/arch/x86/Kconfig
> > > +++ b/arch/x86/Kconfig
> > > @@ -2393,7 +2393,7 @@ config CC_HAS_NAMED_AS
> > >
> > > config USE_X86_SEG_SUPPORT
> > > def_bool y
> > > - depends on CC_HAS_NAMED_AS && SMP
> > > + depends on CC_HAS_NAMED_AS && SMP && !KASAN
> > > + depends on CC_HAS_NAMED_AS && SMP && !KASAN
> >
> > So I'd rather express this as a Kconfig quirk line, and explain each quirk.
> >
> > Something like:
> >
> > depends on CC_HAS_NAMED_AS
> > depends on SMP
> > #
> > # -fsanitize=kernel-address (KASAN) is at the moment incompatible
> > # with named address spaces - see GCC bug #12345.
> > #
> > depends on !KASAN
> >
> > ... or so.
>
> BTW., while this OK for testing, this is too heavy handed for release
> purposes, so please only disable the KASAN instrumentation for the affected
> 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.
Uros.
> I'd even suggest introducing a new attribute variant, specific to x86,
> prefixed with __no_sanitize_x86_seg or so, which would allow the eventual
> KASAN-instrumentation of the percpu accessors once the underlying GCC bug
> is fixed.
>
> Thanks,
>
> Ingo
next prev parent reply other threads:[~2023-10-09 12:01 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-04 14:49 [PATCH 0/4] x86/percpu: Use segment qualifiers Uros Bizjak
2023-10-04 14:49 ` [PATCH 1/4] x86/percpu: Update arch/x86/include/asm/percpu.h to the current tip Uros Bizjak
2023-10-04 14:49 ` [PATCH 2/4] x86/percpu: Enable named address spaces with known compiler version Uros Bizjak
2023-10-05 7:20 ` [tip: x86/percpu] " tip-bot2 for Uros Bizjak
2023-10-04 14:49 ` [PATCH 3/4] x86/percpu: Use compiler segment prefix qualifier Uros Bizjak
2023-10-05 7:20 ` [tip: x86/percpu] " tip-bot2 for Nadav Amit
2023-10-04 14:49 ` [PATCH 4/4] x86/percpu: Use C for percpu read/write accessors Uros Bizjak
2023-10-04 16:37 ` Ingo Molnar
2023-10-04 16:40 ` Ingo Molnar
2023-10-04 19:23 ` [PATCH v2 " Uros Bizjak
2023-10-04 19:42 ` Linus Torvalds
2023-10-04 20:07 ` Uros Bizjak
2023-10-04 20:12 ` Linus Torvalds
2023-10-04 20:19 ` Linus Torvalds
2023-10-04 20:22 ` Uros Bizjak
2023-10-05 7:06 ` Ingo Molnar
2023-10-05 7:40 ` Uros Bizjak
2023-10-05 7:20 ` [tip: x86/percpu] " tip-bot2 for Uros Bizjak
2023-10-08 17:59 ` [PATCH 4/4] " Linus Torvalds
2023-10-08 19:17 ` Uros Bizjak
2023-10-08 20:13 ` Linus Torvalds
2023-10-08 20:48 ` Linus Torvalds
2023-10-08 21:41 ` Uros Bizjak
2023-10-09 11:41 ` Ingo Molnar
2023-10-09 11:51 ` Ingo Molnar
2023-10-09 12:00 ` Uros Bizjak [this message]
2023-10-09 12:20 ` Ingo Molnar
2023-10-09 12:21 ` Nadav Amit
2023-10-09 12:42 ` Uros Bizjak
2023-10-09 12:53 ` Nadav Amit
2023-10-09 12:27 ` Uros Bizjak
2023-10-09 14:35 ` Uros Bizjak
2024-04-10 11:11 ` Andrey Konovalov
2024-04-10 11:21 ` Uros Bizjak
2024-04-10 11:24 ` Andrey Konovalov
2023-10-09 11:42 ` Ingo Molnar
2023-10-10 6:37 ` Uros Bizjak
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