linux-kernel - Re: [PATCH] MIPS: fix duplicate definitions for exported symbols

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Message-ID: <Y2LEvg5PEdbAtQ3e@dev-arch.thelio-3990X>
Date:   Wed, 2 Nov 2022 12:27:58 -0700
From:   Nathan Chancellor <nathan@...nel.org>
To:     Rongwei Zhang <pudh4418@...il.com>
Cc:     Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Ralf Baechle <ralf@...ux-mips.org>,
        Maxim Uvarov <muvarov@...il.com>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Tom Rix <trix@...hat.com>, linux-mips@...r.kernel.org,
        linux-kernel@...r.kernel.org, llvm@...ts.linux.dev
Subject: Re: [PATCH] MIPS: fix duplicate definitions for exported symbols

On Wed, Nov 02, 2022 at 08:27:39PM +0800, Rongwei Zhang wrote:
> Building with clang-14 fails with:
> 
> AS      arch/mips/kernel/relocate_kernel.o
> <unknown>:0: error: symbol 'kexec_args' is already defined
> <unknown>:0: error: symbol 'secondary_kexec_args' is already defined
> <unknown>:0: error: symbol 'kexec_start_address' is already defined
> <unknown>:0: error: symbol 'kexec_indirection_page' is already defined
> <unknown>:0: error: symbol 'relocate_new_kernel_size' is already defined
> 
> It turns out EXPORT defined in asm/asm.h expands to a symbol definition,
> so there is no need to define these symbols again. Remove duplicated
> symbol definitions.
> 
> Fixes: 7aa1c8f47e7e ("MIPS: kdump: Add support")
> Signed-off-by: Rongwei Zhang <pudh4418@...il.com>

Indeed. I had a similar diff when I looked into this late last year but
I never got around to sending that diff.

https://github.com/ClangBuiltLinux/linux/issues/1528#issuecomment-988235109

Reviewed-by: Nathan Chancellor <nathan@...nel.org>

Thanks for the patch!

> ---
>  arch/mips/kernel/relocate_kernel.S | 15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/mips/kernel/relocate_kernel.S b/arch/mips/kernel/relocate_kernel.S
> index cfde14b48fd8..f5b2ef979b43 100644
> --- a/arch/mips/kernel/relocate_kernel.S
> +++ b/arch/mips/kernel/relocate_kernel.S
> @@ -145,8 +145,7 @@ LEAF(kexec_smp_wait)
>   * kexec_args[0..3] are used to prepare register values.
>   */
>  
> -kexec_args:
> -	EXPORT(kexec_args)
> +EXPORT(kexec_args)
>  arg0:	PTR_WD		0x0
>  arg1:	PTR_WD		0x0
>  arg2:	PTR_WD		0x0
> @@ -159,8 +158,7 @@ arg3:	PTR_WD		0x0
>   * their registers a0-a3. secondary_kexec_args[0..3] are used
>   * to prepare register values.
>   */
> -secondary_kexec_args:
> -	EXPORT(secondary_kexec_args)
> +EXPORT(secondary_kexec_args)
>  s_arg0: PTR_WD		0x0
>  s_arg1: PTR_WD		0x0
>  s_arg2: PTR_WD		0x0
> @@ -171,19 +169,16 @@ kexec_flag:
>  
>  #endif
>  
> -kexec_start_address:
> -	EXPORT(kexec_start_address)
> +EXPORT(kexec_start_address)
>  	PTR_WD		0x0
>  	.size		kexec_start_address, PTRSIZE
>  
> -kexec_indirection_page:
> -	EXPORT(kexec_indirection_page)
> +EXPORT(kexec_indirection_page)
>  	PTR_WD		0
>  	.size		kexec_indirection_page, PTRSIZE
>  
>  relocate_new_kernel_end:
>  
> -relocate_new_kernel_size:
> -	EXPORT(relocate_new_kernel_size)
> +EXPORT(relocate_new_kernel_size)
>  	PTR_WD		relocate_new_kernel_end - relocate_new_kernel
>  	.size		relocate_new_kernel_size, PTRSIZE
> -- 
> 2.38.1
>