Re: FAILED: patch "[PATCH] powerpc: Make setjmp/longjmp signature standard" failed to apply to 4.19-stable tree

From: Nathan Chancellor <natechancellor@gmail.com>
To: gregkh@linuxfoundation.org
Cc: courbet@google.com, mpe@ellerman.id.au, stable@vger.kernel.org
Subject: Re: FAILED: patch "[PATCH] powerpc: Make setjmp/longjmp signature standard" failed to apply to 4.19-stable tree
Date: Wed, 15 Apr 2020 09:14:05 -0700	[thread overview]
Message-ID: <20200415161405.GB44996@ubuntu-s3-xlarge-x86> (raw)
In-Reply-To: <158695654686139@kroah.com>

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On Wed, Apr 15, 2020 at 03:15:46PM +0200, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 4.19-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
> 
> thanks,
> 
> greg k-h
> 
> ------------------ original commit in Linus's tree ------------------
> 
> From c17eb4dca5a353a9dbbb8ad6934fe57af7165e91 Mon Sep 17 00:00:00 2001
> From: Clement Courbet <courbet@google.com>
> Date: Mon, 30 Mar 2020 10:03:56 +0200
> Subject: [PATCH] powerpc: Make setjmp/longjmp signature standard
> 
> 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.
> 
> Fixes: c9029ef9c957 ("powerpc: Avoid clang warnings around setjmp and longjmp")
> Cc: stable@vger.kernel.org # v4.14+
> Signed-off-by: Clement Courbet <courbet@google.com>
> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> Tested-by: Nathan Chancellor <natechancellor@gmail.com>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> Link: https://lore.kernel.org/r/20200330080400.124803-1-courbet@google.com
> 
> diff --git a/arch/powerpc/include/asm/setjmp.h b/arch/powerpc/include/asm/setjmp.h
> index e9f81bb3f83b..f798e80e4106 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[JMP_BUF_LEN];
> +
> +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
> diff --git a/arch/powerpc/xmon/Makefile b/arch/powerpc/xmon/Makefile
> index c3842dbeb1b7..6f9cccea54f3 100644
> --- a/arch/powerpc/xmon/Makefile
> +++ b/arch/powerpc/xmon/Makefile
> @@ -1,9 +1,6 @@
>  # SPDX-License-Identifier: GPL-2.0
>  # Makefile for xmon
>  
> -# Avoid clang warnings around longjmp/setjmp declarations
> -subdir-ccflags-y := -ffreestanding
> -
>  GCOV_PROFILE := n
>  KCOV_INSTRUMENT := n
>  UBSAN_SANITIZE := n
> 

Attached is a backport for 4.19 (that patch plus a prerequisite one).

Cheers,
Nathan

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