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Subject: Re: [PATCH v1] arm64: tlb: fix the TTL value of tlb_get_level
To:     Will Deacon <will@kernel.org>
CC:     Catalin Marinas <catalin.marinas@arm.com>,
        <aneesh.kumar@linux.ibm.com>, Marc Zyngier <maz@kernel.org>,
        <steven.price@arm.com>, Peter Zijlstra <peterz@infradead.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <linux-arch@vger.kernel.org>,
        <linux-mm@kvack.org>, Xiexiangyou <xiexiangyou@huawei.com>,
        <liushixin2@huawei.com>, huyaqin <huyaqin1@huawei.com>,
        <zhurui3@huawei.com>
References: <b80ead47-1f88-3a00-18e1-cacc22f54cc4@huawei.com>
 <20210623110412.GA32177@willie-the-truck>
From:   Zhenyu Ye <yezhenyu2@huawei.com>
Message-ID: <800c06ad-1491-c5ba-c650-c78384bf50c9@huawei.com>
Date:   Thu, 24 Jun 2021 09:55:53 +0800
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On 2021/6/23 19:04, Will Deacon wrote:
> On Wed, Jun 23, 2021 at 03:05:22PM +0800, Zhenyu Ye wrote:
>> diff --git a/arch/arm64/include/asm/tlb.h b/arch/arm64/include/asm/tlb.h
>> index 61c97d3b58c7..c995d1f4594f 100644
>> --- a/arch/arm64/include/asm/tlb.h
>> +++ b/arch/arm64/include/asm/tlb.h
>> @@ -28,6 +28,10 @@ static void tlb_flush(struct mmu_gather *tlb);
>>   */
>>  static inline int tlb_get_level(struct mmu_gather *tlb)
>>  {
>> +	/* The TTL field is only valid for the leaf entry. */
>> +	if (tlb->freed_tables)
>> +		return 0;
>> +
>>  	if (tlb->cleared_ptes && !(tlb->cleared_pmds ||
>>  				   tlb->cleared_puds ||
>>  				   tlb->cleared_p4ds))
> 
> Thanks. I can't see a better way around this, so I'll queue the patch.
> The stage-2 page-table code looks ok afaict, but please can you check it
> too?

The stage-2 page-table codes seem to be correct to me.

Thanks,
Zhenyu