[RFC PATCH v3 2/3] arm64/mm: add set_direct_map_ro_noflush()
From: Xueyuan Chen <hidden>
Date: 2026-07-06 13:07:03
Also in:
linux-mm, lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
From: Xueyuan Chen <redacted> Implement set_direct_map_ro_noflush() for arm64 with update_range_prot() on the linear map, setting PTE_RDONLY and clearing PTE_WRITE. Keep the existing can_set_direct_map() guard and leave TLB invalidation to the caller. Co-developed-by: Lance Yang <lance.yang@linux.dev> Signed-off-by: Lance Yang <lance.yang@linux.dev> Signed-off-by: Xueyuan Chen <redacted> --- arch/arm64/include/asm/set_memory.h | 2 ++ arch/arm64/mm/pageattr.c | 10 ++++++++++ 2 files changed, 12 insertions(+)
diff --git a/arch/arm64/include/asm/set_memory.h b/arch/arm64/include/asm/set_memory.h
index 90f61b17275e..7083260303c3 100644
--- a/arch/arm64/include/asm/set_memory.h
+++ b/arch/arm64/include/asm/set_memory.h@@ -14,6 +14,8 @@ int set_memory_valid(unsigned long addr, int numpages, int enable); int set_direct_map_invalid_noflush(struct page *page); int set_direct_map_default_noflush(struct page *page); int set_direct_map_valid_noflush(struct page *page, unsigned nr, bool valid); +int set_direct_map_ro_noflush(const void *addr, unsigned long nr_pages); +#define set_direct_map_ro_noflush set_direct_map_ro_noflush bool kernel_page_present(struct page *page); int set_memory_encrypted(unsigned long addr, int numpages);
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index bbe98ac9ad8c..1a6769073558 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c@@ -365,6 +365,16 @@ int set_direct_map_valid_noflush(struct page *page, unsigned nr, bool valid) return set_memory_valid(addr, nr, valid); } +int set_direct_map_ro_noflush(const void *addr, unsigned long nr_pages) +{ + if (!can_set_direct_map()) + return 0; + + return update_range_prot((unsigned long)addr, PAGE_SIZE * nr_pages, + __pgprot(PTE_RDONLY), + __pgprot(PTE_WRITE)); +} + #ifdef CONFIG_DEBUG_PAGEALLOC /* * This is - apart from the return value - doing the same
--
2.49.0