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From: Michael Ellerman <mpe@ellerman.id.au>
To: Marco Elver <elver@google.com>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Potapenko <glider@google.com>,
	Andrey Ryabinin <ryabinin.a.a@gmail.com>,
	Andrey Konovalov <andreyknvl@gmail.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Nicholas Piggin <npiggin@gmail.com>,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	Liam Howlett <liam.howlett@oracle.com>,
	kasan-dev@googlegroups.com, linuxppc-dev@lists.ozlabs.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Daniel Axtens <dja@axtens.net>, kernel test robot <lkp@intel.com>
Subject: Re: [PATCH mm] kasan, powerpc: Don't rename memintrinsics if compiler adds prefixes
Date: Tue, 28 Feb 2023 22:58:03 +1100	[thread overview]
Message-ID: <87o7peuhmc.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <CANpmjNNtxW41H8ju6iog=ynMdEE0awa7GYabsuL6ZRihmVYQHw@mail.gmail.com>

Marco Elver <elver@google.com> writes:
> On Mon, 27 Feb 2023 at 23:16, Andrew Morton <akpm@linux-foundation.org> wrote:
>>
>> On Mon, 27 Feb 2023 10:47:27 +0100 Marco Elver <elver@google.com> wrote:
>>
>> > With appropriate compiler support [1], KASAN builds use __asan prefixed
>> > meminstrinsics, and KASAN no longer overrides memcpy/memset/memmove.
>> >
>> > If compiler support is detected (CC_HAS_KASAN_MEMINTRINSIC_PREFIX),
>> > define memintrinsics normally (do not prefix '__').
>> >
>> > On powerpc, KASAN is the only user of __mem functions, which are used to
>> > define instrumented memintrinsics. Alias the normal versions for KASAN
>> > to use in its implementation.
>> >
>> > Link: https://lore.kernel.org/all/20230224085942.1791837-1-elver@google.com/ [1]
>> > Link: https://lore.kernel.org/oe-kbuild-all/202302271348.U5lvmo0S-lkp@intel.com/
>> > Reported-by: kernel test robot <lkp@intel.com>
>> > Signed-off-by: Marco Elver <elver@google.com>
>>
>> Seems this is a fix against "kasan: treat meminstrinsic as builtins in
>> uninstrumented files", so I'll plan to fold this patch into that patch.
>
> Yes, that looks right.
>
> If a powerpc maintainer could take a quick look as well would be good.

The patch looks OK to me. It builds for various configs and I did a few
test boots with KASAN enabled, everything seems normal.

Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)


> The maze of memcpy/memmove/memset definitions and redefinitions isn't
> the simplest - I hope in a few years we can delete all the old code
> (before CC_HAS_KASAN_MEMINTRINSIC_PREFIX), and let the compilers just
> "do the right thing".

Yeah that would be nice.

cheers


      reply	other threads:[~2023-02-28 11:58 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-27  9:47 Marco Elver
2023-02-27 22:16 ` Andrew Morton
2023-02-27 23:09   ` Marco Elver
2023-02-28 11:58     ` Michael Ellerman [this message]

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