[PATCH v3 04/11] arm64/mm: Add set_memory_device() and set_memory_normal()

[Thierry Reding]

From: Chun Ng <chunn@xxxxxxxxxx>

Add helpers to swap PROT_NORMAL and PROT_DEVICE_nGnRnE protection bits
on a kernel-linear-map range.

Signed-off-by: Chun Ng <chunn@xxxxxxxxxx>
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
---
 arch/arm64/include/asm/set_memory.h |  2 ++
 arch/arm64/mm/pageattr.c            | 16 ++++++++++++++++
 include/linux/set_memory.h          | 11 +++++++++++
 3 files changed, 29 insertions(+)

diff --git a/arch/arm64/include/asm/set_memory.h b/arch/arm64/include/asm/set_memory.h
index 90f61b17275e..6a7030609789 100644
--- a/arch/arm64/include/asm/set_memory.h
+++ b/arch/arm64/include/asm/set_memory.h
@@ -10,6 +10,8 @@ bool can_set_direct_map(void);
 #define can_set_direct_map can_set_direct_map
 
 int set_memory_valid(unsigned long addr, int numpages, int enable);
+int set_memory_device(unsigned long addr, int numpages);
+int set_memory_normal(unsigned long addr, int numpages);
 
 int set_direct_map_invalid_noflush(struct page *page);
 int set_direct_map_default_noflush(struct page *page);
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index bbe98ac9ad8c..871b59a6c9ea 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -251,6 +251,22 @@ int set_memory_valid(unsigned long addr, int numpages, int enable)
 					__pgprot(PTE_PRESENT_VALID_KERNEL));
 }
 
+int set_memory_device(unsigned long addr, int numpages)
+{
+	return __change_memory_common(addr, PAGE_SIZE * numpages,
+				__pgprot(PROT_DEVICE_nGnRnE),
+				__pgprot(PROT_NORMAL));
+}
+EXPORT_SYMBOL_GPL(set_memory_device);
+
+int set_memory_normal(unsigned long addr, int numpages)
+{
+	return __change_memory_common(addr, PAGE_SIZE * numpages,
+				__pgprot(PROT_NORMAL),
+				__pgprot(PROT_DEVICE_nGnRnE));
+}
+EXPORT_SYMBOL_GPL(set_memory_normal);
+
 int set_direct_map_invalid_noflush(struct page *page)
 {
 	pgprot_t clear_mask = __pgprot(PTE_PRESENT_VALID_KERNEL);
diff --git a/include/linux/set_memory.h b/include/linux/set_memory.h
index 3030d9245f5a..abcb11378fdb 100644
--- a/include/linux/set_memory.h
+++ b/include/linux/set_memory.h
@@ -72,6 +72,17 @@ static inline int clear_mce_nospec(unsigned long pfn)
 }
 #endif
 
+#ifndef CONFIG_ARM64
+static inline int set_memory_device(unsigned long addr, int numpages)
+{
+	return 0;
+}
+static inline int set_memory_normal(unsigned long addr, int numpages)
+{
+	return 0;
+}
+#endif
+
 #ifndef CONFIG_ARCH_HAS_MEM_ENCRYPT
 static inline int set_memory_encrypted(unsigned long addr, int numpages)
 {

-- 
2.54.0