From: Catalin Marinas <catalin.marinas@arm.com>
To: Tong Tiangen <tongtiangen@huawei.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
Subject: Re: [PATCH -next 3/4] arm64: mm: add support for page table check
Date: Thu, 17 Mar 2022 19:00:04 +0000 [thread overview]
Message-ID: <YjOFNEvj7EfBasCI@arm.com> (raw)
In-Reply-To: <20220317141203.3646253-4-tongtiangen@huawei.com>
On Thu, Mar 17, 2022 at 02:12:02PM +0000, Tong Tiangen wrote:
> @@ -628,6 +647,25 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
> #define pud_leaf(pud) pud_sect(pud)
> #define pud_valid(pud) pte_valid(pud_pte(pud))
>
> +#ifdef CONFIG_PAGE_TABLE_CHECK
> +static inline bool pte_user_accessible_page(pte_t pte)
> +{
> + return (pte_val(pte) & PTE_VALID) && (pte_val(pte) & PTE_USER);
> +}
There is another class of user mappings, execute-only, that have both
PTE_USER and PTE_UXN cleared. So this logic should be:
pte_valid(pte) && (pte_user(pte) || pte_user_exec(pte))
with pte_user() as:
#define pte_user(pte) (!!(pte_val(pte) & PTE_USER))
Do we care about PROT_NONE mappings here? They have the valid bit
cleared but pte_present() is true.
> +static inline bool pmd_user_accessible_page(pmd_t pmd)
> +{
> + return pmd_leaf(pmd) && (pmd_val(pmd) & PTE_VALID) &&
> + (pmd_val(pmd) & PTE_USER);
> +}
pmd_leaf() implies valid, so you can skip it if that's the aim.
Similar comment to the pte variant on execute-only and PROT_NONE
mappings.
--
Catalin
next prev parent reply other threads:[~2022-03-17 19:00 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-17 14:11 [PATCH -next 0/4]mm: page_table_check: add support on arm64 and riscv Tong Tiangen
2022-03-17 14:12 ` [PATCH -next 1/4] mm: page_table_check: move pxx_user_accessible_page into x86 Tong Tiangen
2022-03-17 14:12 ` [PATCH -next 2/4] mm: page_table_check: add hooks to public helpers Tong Tiangen
2022-03-17 14:12 ` [PATCH -next 3/4] arm64: mm: add support for page table check Tong Tiangen
2022-03-17 19:00 ` Catalin Marinas [this message]
2022-03-18 3:58 ` Tong Tiangen
2022-03-18 17:18 ` Catalin Marinas
2022-03-21 6:15 ` Tong Tiangen
2022-03-21 16:40 ` Catalin Marinas
2022-03-22 3:07 ` Tong Tiangen
2022-03-17 14:12 ` [PATCH -next 4/4] riscv: " Tong Tiangen
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