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From: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
To: Luming Yu <luming.yu@shingroup.cn>, linuxppc-dev@lists.ozlabs.org,
	linux-kernel@vger.kernel.org, mpe@ellerman.id.au, npiggin@gmail.com,
	christophe.leroy@csgroup.eu
Cc: luming.yu@gmail.com, ke.zhao@shingroup.cn, dawei.li@shingroup.cn,
	shenghui.qu@shingroup.cn, Luming Yu <luming.yu@shingroup.cn>
Subject: Re: [PATCH v1 2/2] powerpc/debug: hook to user return notifier
 infrastructure
In-Reply-To: <B375A36C9C4D73FF+20231218031338.2084-1-luming.yu@shingroup.cn>
References: <B375A36C9C4D73FF+20231218031338.2084-1-luming.yu@shingroup.cn>
Date: Mon, 18 Dec 2023 14:54:53 +0530
Message-ID: <8734vzsw0q.fsf@kernel.org>
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Luming Yu <luming.yu@shingroup.cn> writes:

> Before we have powerpc to use the generic entry infrastructure,
> the call to fire user return notifier is made temporarily in powerpc
> entry code.
>

It is still not clear what will be registered as user return notifier.
Can you summarize that here?

>
> Signed-off-by: Luming Yu <luming.yu@shingroup.cn>
> ---
>  arch/powerpc/kernel/interrupt.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
> index c4f6d3c69ba9..7fe704946e96 100644
> --- a/arch/powerpc/kernel/interrupt.c
> +++ b/arch/powerpc/kernel/interrupt.c
> @@ -19,6 +19,7 @@
>  #include <asm/time.h>
>  #include <asm/tm.h>
>  #include <asm/unistd.h>
> +#include <asm/entry-common.h>
>  
>  #if defined(CONFIG_PPC_ADV_DEBUG_REGS) && defined(CONFIG_PPC32)
>  unsigned long global_dbcr0[NR_CPUS];
> @@ -245,6 +246,8 @@ interrupt_exit_user_prepare_main(unsigned long ret, struct pt_regs *regs)
>  	/* Restore user access locks last */
>  	kuap_user_restore(regs);
>  
> +	arch_exit_to_user_mode_prepare(regs, ti_flags);
> +
>

That will run the notifier with user AMR/IAMR values. 

>  	return ret;
>  }
>  
> -- 
> 2.42.0.windows.2