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From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Fri, 9 Sep 2022 10:36:00 +0200
Message-ID: <CACT4Y+bY1SkME7343-EZw_C2tORWrJU0MweArrPf2om8R_wfoQ@mail.gmail.com>
Subject: Re: [PATCH v2 1/3] s390: Always declare __mem functions
To:     Marco Elver <elver@google.com>
Cc:     "Paul E. McKenney" <paulmck@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Potapenko <glider@google.com>,
        Boqun Feng <boqun.feng@gmail.com>, kasan-dev@googlegroups.com,
        linux-kernel@vger.kernel.org,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        llvm@lists.linux.dev, Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Christian Borntraeger <borntraeger@linux.ibm.com>,
        Sven Schnelle <svens@linux.ibm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        linux-s390@vger.kernel.org
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On Fri, 9 Sept 2022 at 09:38, Marco Elver <elver@google.com> wrote:
>
> Like other architectures, always declare __mem*() functions if the
> architecture defines __HAVE_ARCH_MEM*.
>
> For example, this is required by sanitizer runtimes to unambiguously
> refer to the arch versions of the mem-functions, and the compiler not
> attempting any "optimizations" such as replacing the calls with builtins
> (which may later be inlined etc.).
>
> Signed-off-by: Marco Elver <elver@google.com>

Acked-by: Dmitry Vyukov <dvyukov@google.com>

> ---
> v2:
> * New patch.
> ---
>  arch/s390/include/asm/string.h | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/arch/s390/include/asm/string.h b/arch/s390/include/asm/string.h
> index 3fae93ddb322..2c3c48d526b9 100644
> --- a/arch/s390/include/asm/string.h
> +++ b/arch/s390/include/asm/string.h
> @@ -20,8 +20,11 @@
>  #define __HAVE_ARCH_MEMSET64   /* arch function */
>
>  void *memcpy(void *dest, const void *src, size_t n);
> +void *__memcpy(void *dest, const void *src, size_t n);
>  void *memset(void *s, int c, size_t n);
> +void *__memset(void *s, int c, size_t n);
>  void *memmove(void *dest, const void *src, size_t n);
> +void *__memmove(void *dest, const void *src, size_t n);
>
>  #ifndef CONFIG_KASAN
>  #define __HAVE_ARCH_MEMCHR     /* inline & arch function */
> @@ -55,10 +58,6 @@ char *strstr(const char *s1, const char *s2);
>
>  #if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)
>
> -extern void *__memcpy(void *dest, const void *src, size_t n);
> -extern void *__memset(void *s, int c, size_t n);
> -extern void *__memmove(void *dest, const void *src, size_t n);
> -
>  /*
>   * For files that are not instrumented (e.g. mm/slub.c) we
>   * should use not instrumented version of mem* functions.
> --
> 2.37.2.789.g6183377224-goog
>