From: Nick Desaulniers <ndesaulniers@google.com>
To: Clement Courbet <courbet@google.com>
Cc: Nathan Chancellor <natechancellor@gmail.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Segher Boessenkool <segher@kernel.crashing.org>,
Christophe Leroy <christophe.leroy@c-s.fr>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
LKML <linux-kernel@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH v1] powerpc: Make setjmp/longjump signature standard
Date: Fri, 27 Mar 2020 10:10:44 -0700 [thread overview]
Message-ID: <CAKwvOdmLmfJY4Uk-Atd9dT5+zQTPeoagjMZMcDqdVfKCU7_BuA@mail.gmail.com> (raw)
In-Reply-To: <20200327100801.161671-1-courbet@google.com>
On Fri, Mar 27, 2020 at 3:08 AM Clement Courbet <courbet@google.com> wrote:
>
> Declaring setjmp()/longjmp() as taking longs makes the signature
> non-standard, and makes clang complain. In the past, this has been
> worked around by adding -ffreestanding to the compile flags.
>
> The implementation looks like it only ever propagates the value
> (in longjmp) or sets it to 1 (in setjmp), and we only call longjmp
> with integer parameters.
>
> This allows removing -ffreestanding from the compilation flags.
>
> Context:
> https://lore.kernel.org/patchwork/patch/1214060
> https://lore.kernel.org/patchwork/patch/1216174
>
> Signed-off-by: Clement Courbet <courbet@google.com>
Hi Clement, thanks for the patch! Would you mind sending a V2 that
included a similar fix to arch/powerpc/xmon/Makefile?
For context, this was the original patch:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=aea447141c7e7824b81b49acd1bc78
which was then modified to:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c9029ef9c95765e7b63c4d9aa780674447db1ec0
So on your V2, if you include in the commit message, the line:
Fixes c9029ef9c957 ("powerpc: Avoid clang warnings around setjmp and longjmp")
then that will help our LTS branch maintainers back port it to the
appropriate branches.
>
> ---
> arch/powerpc/include/asm/setjmp.h | 6 ++++--
> arch/powerpc/kexec/Makefile | 3 ---
> 2 files changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/setjmp.h b/arch/powerpc/include/asm/setjmp.h
> index e9f81bb3f83b..84bb0d140d59 100644
> --- a/arch/powerpc/include/asm/setjmp.h
> +++ b/arch/powerpc/include/asm/setjmp.h
> @@ -7,7 +7,9 @@
>
> #define JMP_BUF_LEN 23
>
> -extern long setjmp(long *) __attribute__((returns_twice));
> -extern void longjmp(long *, long) __attribute__((noreturn));
> +typedef long *jmp_buf;
> +
> +extern int setjmp(jmp_buf env) __attribute__((returns_twice));
> +extern void longjmp(jmp_buf env, int val) __attribute__((noreturn));
>
> #endif /* _ASM_POWERPC_SETJMP_H */
> diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
> index 378f6108a414..86380c69f5ce 100644
> --- a/arch/powerpc/kexec/Makefile
> +++ b/arch/powerpc/kexec/Makefile
> @@ -3,9 +3,6 @@
> # Makefile for the linux kernel.
> #
>
> -# Avoid clang warnings around longjmp/setjmp declarations
> -CFLAGS_crash.o += -ffreestanding
> -
> obj-y += core.o crash.o core_$(BITS).o
>
> obj-$(CONFIG_PPC32) += relocate_32.o
> --
> 2.25.1.696.g5e7596f4ac-goog
>
--
Thanks,
~Nick Desaulniers
next prev parent reply other threads:[~2020-03-27 17:11 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-27 10:07 [PATCH v1] powerpc: Make setjmp/longjump signature standard Clement Courbet
2020-03-27 17:10 ` Nick Desaulniers [this message]
2020-03-27 17:27 ` Nathan Chancellor
2020-03-27 17:45 ` Christophe Leroy
2020-03-27 18:27 ` Nathan Chancellor
2020-03-30 6:42 ` Clement Courbet
2020-03-30 6:43 ` [PATCH v2] powerpc: Make setjmp/longjmp " Clement Courbet
2020-03-30 7:57 ` Nathan Chancellor
2020-03-30 8:03 ` [PATCH v3] " Clement Courbet
2020-03-30 16:20 ` Nick Desaulniers
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