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Date:   Tue, 22 Mar 2022 11:07:22 +0800
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Subject: Re: [PATCH -next 3/4] arm64: mm: add support for page table check
To:     Catalin Marinas <catalin.marinas@arm.com>
CC:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, <x86@kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Pasha Tatashin <pasha.tatashin@soleen.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Will Deacon" <will@kernel.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        "Palmer Dabbelt" <palmer@dabbelt.com>,
        Palmer Dabbelt <palmerdabbelt@google.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-riscv@lists.infradead.org>
References: <20220317141203.3646253-1-tongtiangen@huawei.com>
 <20220317141203.3646253-4-tongtiangen@huawei.com> <YjOFNEvj7EfBasCI@arm.com>
 <cb91532b-c0cd-034c-2f93-4f76fabf5fc1@huawei.com> <YjS+2FVpq8D4Gx0S@arm.com>
 <d3006048-f737-439e-b985-cfbab69c4167@huawei.com> <Yjiqm6tQB5To5Jd9@arm.com>
From:   Tong Tiangen <tongtiangen@huawei.com>
In-Reply-To: <Yjiqm6tQB5To5Jd9@arm.com>
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在 2022/3/22 0:40, Catalin Marinas 写道:
> On Mon, Mar 21, 2022 at 02:15:36PM +0800, Tong Tiangen wrote:
>> Considering all your suggestions, The final logic should be:
>>
>> +#define pte_user(pte)          (!!(pte_val(pte) & PTE_USER))
>>
>> +#define pmd_user(pmd)		pte_user(pmd_pte(pmd))
>> +#define pmd_user_exec(pmd)	pte_user_exec(pmd_pte(pmd))
>>
>> +#define pud_user(pud)          pte_user(pud_pte(pud))
>>
>> +static inline bool pte_user_accessible_page(pte_t pte)
>> +{
>> +	return pte_present(pte) && (pte_user(pte)|| pte_user_exec(pte));
>> +}
> 
> This is fine.
> 
>> +static inline bool pmd_user_accessible_page(pmd_t pmd)
>> +{
>> +	return pmd_present(pmd) && (pmd_user(pmd)|| pmd_user_exec(pmd));
>> +}
> 
> That's fine as well assuming that the function is only called on the
> set_pmd_at() path where we know that the pmd would be a block mapping
> (huge page). I think that's the case from a quick look at the current
> x86 implementation.

Yeah, PTC only check pmd block mapping(huge page) and pud is similar.
These code logic will be included in V2.

Thanks.

> 
>> +static inline bool pud_user_accessible_page(pud_t pud)
>> +{
>> +	return pud_present(pud) && pud_user(pud);
>> +}
> 
> Same here.
>