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Date:   Mon, 28 Oct 2019 16:41:51 +0000
From:   Will Deacon <will@kernel.org>
To:     Xiang Zheng <zhengxiang9@huawei.com>
Cc:     catalin.marinas@arm.com, james.morse@arm.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        wanghaibin.wang@huawei.com
Subject: Re: [PATCH] arm64: print additional fault message when executing
 non-exec memory
Message-ID: <20191028164150.GG5576@willie-the-truck>
References: <20191028090837.39652-1-zhengxiang9@huawei.com>
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On Mon, Oct 28, 2019 at 05:08:37PM +0800, Xiang Zheng wrote:
> When attempting to executing non-executable memory, the fault message
> shows:
> 
>   Unable to handle kernel read from unreadable memory at virtual address
>   ffff802dac469000
> 
> This may confuse someone, so add a new fault message for instruction
> abort.
> 
> Signed-off-by: Xiang Zheng <zhengxiang9@huawei.com>
> ---
>  arch/arm64/mm/fault.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
> index 9fc6db0bcbad..68bf4ec376d0 100644
> --- a/arch/arm64/mm/fault.c
> +++ b/arch/arm64/mm/fault.c
> @@ -318,6 +318,8 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr,
>  	if (is_el1_permission_fault(addr, esr, regs)) {
>  		if (esr & ESR_ELx_WNR)
>  			msg = "write to read-only memory";
> +		else if (is_el1_instruction_abort(esr))
> +			msg = "execute non-executable memory";

nit, please make this "execute from non-executable memory".

With that:

Acked-by: Will Deacon <will@kernel.org>

Will