linux-kernel - Re: [PATCH] openrisc: define arch-specific version of nop()

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Message-ID: <aW_WQfaa4zzO6YR5@antec>
Date: Tue, 20 Jan 2026 19:23:45 +0000
From: Stafford Horne <shorne@...il.com>
To: Brian Masney <bmasney@...hat.com>
Cc: Jonas Bonn <jonas@...thpole.se>,
	Stefan Kristiansson <stefan.kristiansson@...nalahti.fi>,
	linux-openrisc@...r.kernel.org, linux-kernel@...r.kernel.org,
	kernel test robot <lkp@...el.com>
Subject: Re: [PATCH] openrisc: define arch-specific version of nop()

On Tue, Jan 20, 2026 at 12:07:23PM -0500, Brian Masney wrote:
> When compiling a driver written for MIPS on OpenRISC that uses the nop()
> function, it fails due to the following error:
> 
>     drivers/watchdog/pic32-wdt.c: Assembler messages:
>     drivers/watchdog/pic32-wdt.c:125: Error: unrecognized instruction `nop'
> 
> The driver currently uses the generic version of nop() from
> include/asm-generic/barrier.h:
> 
>     #ifndef nop
>     #define nop()   asm volatile ("nop")
>     #endif
> 
> Let's fix this on OpenRISC by defining an architecture-specific version
> of nop().
> 
> This was tested by performing an allmodconfig openrisc cross compile on
> an aarch64 host.
> 
> Reported-by: kernel test robot <lkp@...el.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202601180236.BVy480We-lkp@intel.com/
> Signed-off-by: Brian Masney <bmasney@...hat.com>

This looks OK to me.  Queueing.

-Stafford

> ---
>  arch/openrisc/include/asm/barrier.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/openrisc/include/asm/barrier.h b/arch/openrisc/include/asm/barrier.h
> index 7538294721bed7bc8da3d08f3db89a408091f3f8..8e592c99090235423a9f4c9149da9822918afb13 100644
> --- a/arch/openrisc/include/asm/barrier.h
> +++ b/arch/openrisc/include/asm/barrier.h
> @@ -4,6 +4,8 @@
>  
>  #define mb() asm volatile ("l.msync" ::: "memory")
>  
> +#define nop() asm volatile ("l.nop")
> +
>  #include <asm-generic/barrier.h>
>  
>  #endif /* __ASM_BARRIER_H */
> 
> ---
> base-commit: d08c85ac8894995d4b0d8fb48d2f6a3e53cd79ab
> change-id: 20260120-openrisc-nop-82b7f95dad7f
> 
> Best regards,
> -- 
> Brian Masney <bmasney@...hat.com>
>