[PATCH v7 2/3] arm64/mm: add set_direct_map_ro()

[Xueyuan Chen]

Implement set_direct_map_ro() for arm64 and flush the TLB internally.

Co-developed-by: Lance Yang <lance.yang at linux.dev>
Signed-off-by: Lance Yang <lance.yang at linux.dev>
Signed-off-by: Xueyuan Chen <xueyuan.chen21 at gmail.com>
---
 arch/arm64/include/asm/set_memory.h |  2 ++
 arch/arm64/mm/pageattr.c            | 12 ++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/arch/arm64/include/asm/set_memory.h b/arch/arm64/include/asm/set_memory.h
index 0091ba12200e..1be86dc11543 100644
--- a/arch/arm64/include/asm/set_memory.h
+++ b/arch/arm64/include/asm/set_memory.h
@@ -13,6 +13,8 @@ int set_memory_valid(unsigned long addr, int numpages, int enable);
 
 int set_direct_map_invalid_noflush(struct page *page, unsigned int numpages);
 int set_direct_map_default_noflush(struct page *page, unsigned int numpages);
+int set_direct_map_ro(struct page *page, unsigned int nr);
+#define set_direct_map_ro set_direct_map_ro
 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 132938b32eb1..0e95cd904ccb 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -355,6 +355,18 @@ int realm_register_memory_enc_ops(void)
 	return arm64_mem_crypt_ops_register(&realm_crypt_ops);
 }
 
+int set_direct_map_ro(struct page *page, unsigned int nr)
+{
+	unsigned long addr = (unsigned long)page_address(page);
+
+	if (!can_set_direct_map())
+		return 0;
+
+	return __change_memory_common(addr, PAGE_SIZE * nr,
+				      __pgprot(PTE_RDONLY),
+				      __pgprot(PTE_WRITE));
+}
+
 #ifdef CONFIG_DEBUG_PAGEALLOC
 void __kernel_map_pages(struct page *page, int numpages, int enable)
 {
-- 
2.47.3