[PATCH 5/6] nios2/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Anshuman Khandual]

This defines and exports a platform specific custom vm_get_page_prot() via
subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
macros can be dropped which are no longer needed.

Cc: Dinh Nguyen <dinguyen@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Acked-by: Dinh Nguyen <dinguyen@xxxxxxxxxx>
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
 arch/nios2/Kconfig               |  1 +
 arch/nios2/include/asm/pgtable.h | 24 ----------------
 arch/nios2/mm/init.c             | 47 ++++++++++++++++++++++++++++++++
 3 files changed, 48 insertions(+), 24 deletions(-)

diff --git a/arch/nios2/Kconfig b/arch/nios2/Kconfig
index 4167f1eb4cd8..e0459dffd218 100644
--- a/arch/nios2/Kconfig
+++ b/arch/nios2/Kconfig
@@ -6,6 +6,7 @@ config NIOS2
 	select ARCH_HAS_SYNC_DMA_FOR_CPU
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
 	select ARCH_HAS_DMA_SET_UNCACHED
+	select ARCH_HAS_VM_GET_PAGE_PROT
 	select ARCH_NO_SWAP
 	select COMMON_CLK
 	select TIMER_OF
diff --git a/arch/nios2/include/asm/pgtable.h b/arch/nios2/include/asm/pgtable.h
index 262d0609268c..3c9f83c22733 100644
--- a/arch/nios2/include/asm/pgtable.h
+++ b/arch/nios2/include/asm/pgtable.h
@@ -34,30 +34,6 @@ struct mm_struct;
 				((x) ? _PAGE_EXEC : 0) |		\
 				((r) ? _PAGE_READ : 0) |		\
 				((w) ? _PAGE_WRITE : 0))
-/*
- * These are the macros that generic kernel code needs
- * (to populate protection_map[])
- */
-
-/* Remove W bit on private pages for COW support */
-#define __P000	MKP(0, 0, 0)
-#define __P001	MKP(0, 0, 1)
-#define __P010	MKP(0, 0, 0)	/* COW */
-#define __P011	MKP(0, 0, 1)	/* COW */
-#define __P100	MKP(1, 0, 0)
-#define __P101	MKP(1, 0, 1)
-#define __P110	MKP(1, 0, 0)	/* COW */
-#define __P111	MKP(1, 0, 1)	/* COW */
-
-/* Shared pages can have exact HW mapping */
-#define __S000	MKP(0, 0, 0)
-#define __S001	MKP(0, 0, 1)
-#define __S010	MKP(0, 1, 0)
-#define __S011	MKP(0, 1, 1)
-#define __S100	MKP(1, 0, 0)
-#define __S101	MKP(1, 0, 1)
-#define __S110	MKP(1, 1, 0)
-#define __S111	MKP(1, 1, 1)
 
 /* Used all over the kernel */
 #define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_CACHED | _PAGE_READ | \
diff --git a/arch/nios2/mm/init.c b/arch/nios2/mm/init.c
index 613fcaa5988a..e867f5d85580 100644
--- a/arch/nios2/mm/init.c
+++ b/arch/nios2/mm/init.c
@@ -124,3 +124,50 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 {
 	return (vma->vm_start == KUSER_BASE) ? "[kuser]" : NULL;
 }
+
+pgprot_t vm_get_page_prot(unsigned long vm_flags)
+{
+	switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
+	/* Remove W bit on private pages for COW support */
+	case VM_NONE:
+		return MKP(0, 0, 0);
+	case VM_READ:
+		return MKP(0, 0, 1);
+	/* COW */
+	case VM_WRITE:
+		return MKP(0, 0, 0);
+	/* COW */
+	case VM_WRITE | VM_READ:
+		return MKP(0, 0, 1);
+	case VM_EXEC:
+		return MKP(1, 0, 0);
+	case VM_EXEC | VM_READ:
+		return MKP(1, 0, 1);
+	/* COW */
+	case VM_EXEC | VM_WRITE:
+		return MKP(1, 0, 0);
+	/* COW */
+	case VM_EXEC | VM_WRITE | VM_READ:
+		return MKP(1, 0, 1);
+	/* Shared pages can have exact HW mapping */
+	case VM_SHARED:
+		return MKP(0, 0, 0);
+	case VM_SHARED | VM_READ:
+		return MKP(0, 0, 1);
+	case VM_SHARED | VM_WRITE:
+		return MKP(0, 1, 0);
+	case VM_SHARED | VM_WRITE | VM_READ:
+		return MKP(0, 1, 1);
+	case VM_SHARED | VM_EXEC:
+		return MKP(1, 0, 0);
+	case VM_SHARED | VM_EXEC | VM_READ:
+		return MKP(1, 0, 1);
+	case VM_SHARED | VM_EXEC | VM_WRITE:
+		return MKP(1, 1, 0);
+	case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ:
+		return MKP(1, 1, 1);
+	default:
+		BUILD_BUG();
+	}
+}
+EXPORT_SYMBOL(vm_get_page_prot);
-- 
2.25.1