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Subject: Re: [PATCH] Revert "arm: mm: qsd8x50: Fix incorrect permission
 faults"
To:     Russell King <linux@armlinux.org.uk>
CC:     Nathan Chancellor <nathan@kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>
References: <20210528074444.17291-1-wangkefeng.wang@huawei.com>
From:   Kefeng Wang <wangkefeng.wang@huawei.com>
Message-ID: <248320ed-494b-937d-734c-c97e0c32038a@huawei.com>
Date:   Wed, 2 Jun 2021 23:14:51 +0800
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Hi Russell, any comment about this patch, thanks.

On 2021/5/28 15:44, Kefeng Wang wrote:
> This reverts commit e220ba60223a9d63e70217e5b112160df8c21cea.
>
> The VERIFY_PERMISSION_FAULT is introduced since 2009 but no
> one use it, just revert it and clean unused comment.
>
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
>   arch/arm/mm/Kconfig     |  2 --
>   arch/arm/mm/abort-ev7.S | 26 --------------------------
>   2 files changed, 28 deletions(-)
>
> diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
> index 35f43d0aa056..8355c3895894 100644
> --- a/arch/arm/mm/Kconfig
> +++ b/arch/arm/mm/Kconfig
> @@ -601,8 +601,6 @@ config CPU_TLB_V6
>   config CPU_TLB_V7
>   	bool
>   
> -config VERIFY_PERMISSION_FAULT
> -	bool
>   endif
>   
>   config CPU_HAS_ASID
> diff --git a/arch/arm/mm/abort-ev7.S b/arch/arm/mm/abort-ev7.S
> index f7cc5d68444b..f81bceacc660 100644
> --- a/arch/arm/mm/abort-ev7.S
> +++ b/arch/arm/mm/abort-ev7.S
> @@ -17,31 +17,5 @@ ENTRY(v7_early_abort)
>   	mrc	p15, 0, r1, c5, c0, 0		@ get FSR
>   	mrc	p15, 0, r0, c6, c0, 0		@ get FAR
>   	uaccess_disable ip			@ disable userspace access
> -
> -	/*
> -	 * V6 code adjusts the returned DFSR.
> -	 * New designs should not need to patch up faults.
> -	 */
> -
> -#if defined(CONFIG_VERIFY_PERMISSION_FAULT)
> -	/*
> -	 * Detect erroneous permission failures and fix
> -	 */
> -	ldr	r3, =0x40d			@ On permission fault
> -	and	r3, r1, r3
> -	cmp	r3, #0x0d
> -	bne	do_DataAbort
> -
> -	mcr	p15, 0, r0, c7, c8, 0   	@ Retranslate FAR
> -	isb
> -	mrc	p15, 0, ip, c7, c4, 0   	@ Read the PAR
> -	and	r3, ip, #0x7b   		@ On translation fault
> -	cmp	r3, #0x0b
> -	bne	do_DataAbort
> -	bic	r1, r1, #0xf			@ Fix up FSR FS[5:0]
> -	and	ip, ip, #0x7e
> -	orr	r1, r1, ip, LSR #1
> -#endif
> -
>   	b	do_DataAbort
>   ENDPROC(v7_early_abort)