From: Arnd Bergmann <arnd@arndb.de>
To: Laura Abbott <labbott@redhat.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Bernd Edlinger <bernd.edlinger@hotmail.de>,
Martin Sebor <msebor@gmail.com>,
Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Subject: Re: [RFC][PATCH] Update -Wattribute-alias for gcc9
Date: Fri, 25 Jan 2019 11:58:21 +0100 [thread overview]
Message-ID: <CAK8P3a0xnc7RNbGhG7-hj+ay2keR7dh7MmDiUNKxfewsnatsgA@mail.gmail.com> (raw)
In-Reply-To: <20190125104353.2791-1-labbott@redhat.com>
On Fri, Jan 25, 2019 at 11:43 AM Laura Abbott <labbott@redhat.com> wrote:
>
> Commit bee20031772a ("disable -Wattribute-alias warning for
> SYSCALL_DEFINEx()") disabled -Wattribute-alias with gcc8.
> gcc9 changed the format of -Wattribute-alias to take a parameter.
> This doesn't quite match with the existing disabling mechanism
> so update for gcc9 to match with the default (-Wattribute-alias=1).
>
> Signed-off-by: Laura Abbott <labbott@redhat.com>
> ---
> This is RFC because it feels ugly. I went ahead and did the obvious fixup
> but it's worth discussing if we're going to end up with an explosion or
> if there's a better way to handle this in one macro.
Bernd Edlinger has sent a patch to gcc for this:
https://gcc.gnu.org/ml/gcc-patches/2019-01/msg01120.html
and Miguel Ojeda said he wanted to send a patch for it to the
kernel as well, not sure if he wanted to take a different
approach there, so adding both to Cc here.
Arnd
> ---
> include/linux/compat.h | 2 ++
> include/linux/compiler-gcc.h | 7 ++++++-
> include/linux/syscalls.h | 2 ++
> 3 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/compat.h b/include/linux/compat.h
> index 056be0d03722..d5d7700f26a6 100644
> --- a/include/linux/compat.h
> +++ b/include/linux/compat.h
> @@ -75,6 +75,8 @@
> __diag_push(); \
> __diag_ignore(GCC, 8, "-Wattribute-alias", \
> "Type aliasing is used to sanitize syscall arguments");\
> + __diag_ignore(GCC, 9, "-Wattribute-alias=1", \
> + "Type aliasing is used to sanitize syscall arguments");\
> asmlinkage long compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
> asmlinkage long compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
> __attribute__((alias(__stringify(__se_compat_sys##name)))); \
> diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
> index e8579412ad21..75079668344c 100644
> --- a/include/linux/compiler-gcc.h
> +++ b/include/linux/compiler-gcc.h
> @@ -165,8 +165,13 @@
> #define __diag_str(s) __diag_str1(s)
> #define __diag(s) _Pragma(__diag_str(GCC diagnostic s))
>
> -#if GCC_VERSION >= 80000
> +#if GCC_VERSION >= 90000
> +#define __diag_GCC_8(s)
> +#define __diag_GCC_9(s) __diag(s)
> +#elif GCC_VERSION >= 80000
> #define __diag_GCC_8(s) __diag(s)
> +#define __diag_GCC_9(s)
> #else
> #define __diag_GCC_8(s)
> +#define __diag_GCC_9(s)
> #endif
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 257cccba3062..a08059e1ccf4 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -236,6 +236,8 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event)
> __diag_push(); \
> __diag_ignore(GCC, 8, "-Wattribute-alias", \
> "Type aliasing is used to sanitize syscall arguments");\
> + __diag_ignore(GCC, 9, "-Wattribute-alias=1", \
> + "Type aliasing is used to sanitize syscall arguments");\
> asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
> __attribute__((alias(__stringify(__se_sys##name)))); \
> ALLOW_ERROR_INJECTION(sys##name, ERRNO); \
> --
> 2.20.1
>
next prev parent reply other threads:[~2019-01-25 10:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-25 10:43 [RFC][PATCH] Update -Wattribute-alias for gcc9 Laura Abbott
2019-01-25 10:58 ` Arnd Bergmann [this message]
2019-01-25 11:39 ` Miguel Ojeda
2019-01-25 12:24 ` Bernd Edlinger
2019-01-28 13:28 ` Bernd Edlinger
2019-01-28 14:35 ` Laura Abbott
2019-01-28 14:40 ` Arnd Bergmann
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