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From: Huangzhaoyang <huangzhaoyang@gmail.com>
To: Ard Biesheuvel <ardb@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Nicholas Piggin <npiggin@gmail.com>,
	Mike Rapoport <rppt@kernel.org>,
	Pavel Tatashin <pasha.tatashin@soleen.com>,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	Jonathan Marek <jonathan@marek.ca>,
	Zhaoyang Huang <zhaoyang.huang@unisoc.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH] mm: introduce alloc hook to apply PTE_CONT
Date: Tue, 23 Nov 2021 17:12:40 +0800	[thread overview]
Message-ID: <1637658760-5813-1-git-send-email-huangzhaoyang@gmail.com> (raw)

From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>

Since there is no PTE_CONT when rodata_full in ARM64, introducing a
hook function to apply PTE_CONT on the proper page blocks.

Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
---
 arch/arm64/include/asm/page.h |  5 +++++
 arch/arm64/mm/pageattr.c      | 45 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index f98c91b..53cdd09 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -46,6 +46,11 @@ struct page *alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
 
 #include <asm/memory.h>
 
+#define HAVE_ARCH_ALLOC_PAGE
+#define HAVE_ARCH_FREE_PAGE
+
+extern void arch_alloc_page(struct page *page, int order);
+extern void arch_free_page(struct page *page, int order);
 #endif /* !__ASSEMBLY__ */
 
 #define VM_DATA_DEFAULT_FLAGS	(VM_DATA_FLAGS_TSK_EXEC | VM_MTE_ALLOWED)
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index a3bacd7..815a06d 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -239,3 +239,48 @@ bool kernel_page_present(struct page *page)
 	ptep = pte_offset_kernel(pmdp, addr);
 	return pte_valid(READ_ONCE(*ptep));
 }
+
+void arch_alloc_page(struct page *page, int order)
+{
+	unsigned long addr;
+	unsigned long cont_pte_low_bound;
+
+	if (!rodata_full)
+		return;
+
+	addr = (u64)page_address(page);
+	if ((order >= 4) && (addr & ~CONT_PTE_MASK) == 0) {
+		order -= 4;
+		do {
+			cont_pte_low_bound = addr & CONT_PTE_MASK;
+			__change_memory_common(cont_pte_low_bound,
+					(~CONT_PTE_MASK + 1), __pgprot(PTE_CONT), __pgprot(0));
+			addr = (u64)page_address(page);
+			page += 4;
+			order--;
+		}while (order >= 0);
+	}
+}
+
+void arch_free_page(struct page *page, int order)
+{
+	unsigned long addr;
+	unsigned long cont_pte_low_bound;
+
+	if (!rodata_full)
+		return;
+
+	addr = (u64)page_address(page);
+	if ((order >= 4) && (addr & ~CONT_PTE_MASK) == 0) {
+		order -= 4;
+		do {
+			cont_pte_low_bound = addr & CONT_PTE_MASK;
+			__change_memory_common(cont_pte_low_bound,
+					(~CONT_PTE_MASK + 1), __pgprot(0), __pgprot(PTE_CONT));
+			addr = (u64)page_address(page);
+			page += 4;
+			order--;
+		}while (order >= 0);
+	}
+}
+
-- 
1.9.1



             reply	other threads:[~2021-11-23  9:13 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-23  9:12 Huangzhaoyang [this message]
2021-11-23  9:57 ` Ard Biesheuvel
2021-11-24  8:08   ` Zhaoyang Huang
2021-11-24  9:23     ` Ard Biesheuvel
2021-11-24 12:00       ` Zhaoyang Huang
2021-11-24 13:54         ` Ard Biesheuvel

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