[RFC V1 15/31] riscv/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: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
 arch/riscv/Kconfig               |  1 +
 arch/riscv/include/asm/pgtable.h | 16 -------------
 arch/riscv/mm/init.c             | 41 ++++++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+), 16 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 5adcbd9b5e88..9391742f9286 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -31,6 +31,7 @@ config RISCV
 	select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
+	select ARCH_HAS_VM_GET_PAGE_PROT
 	select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
 	select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
 	select ARCH_STACKWALK
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 7e949f25c933..d2bb14cac28b 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -183,24 +183,8 @@ extern struct pt_alloc_ops pt_ops __initdata;
 extern pgd_t swapper_pg_dir[];
 
 /* MAP_PRIVATE permissions: xwr (copy-on-write) */
-#define __P000	PAGE_NONE
-#define __P001	PAGE_READ
-#define __P010	PAGE_COPY
-#define __P011	PAGE_COPY
-#define __P100	PAGE_EXEC
-#define __P101	PAGE_READ_EXEC
-#define __P110	PAGE_COPY_EXEC
-#define __P111	PAGE_COPY_READ_EXEC
 
 /* MAP_SHARED permissions: xwr */
-#define __S000	PAGE_NONE
-#define __S001	PAGE_READ
-#define __S010	PAGE_SHARED
-#define __S011	PAGE_SHARED
-#define __S100	PAGE_EXEC
-#define __S101	PAGE_READ_EXEC
-#define __S110	PAGE_SHARED_EXEC
-#define __S111	PAGE_SHARED_EXEC
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 static inline int pmd_present(pmd_t pmd)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index cf4d018b7d66..1cd96ba5398b 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -1048,3 +1048,44 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 	return vmemmap_populate_basepages(start, end, node, NULL);
 }
 #endif
+
+pgprot_t vm_get_page_prot(unsigned long vm_flags)
+{
+	switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
+	case VM_NONE:
+		return PAGE_NONE;
+	case VM_READ:
+		return PAGE_READ;
+	case VM_WRITE:
+		return PAGE_COPY;
+	case VM_READ | VM_WRITE:
+		return PAGE_COPY;
+	case VM_EXEC:
+		return PAGE_EXEC;
+	case VM_EXEC | VM_READ:
+		return PAGE_READ_EXEC;
+	case VM_EXEC | VM_WRITE:
+		return PAGE_COPY_EXEC;
+	case VM_EXEC | VM_READ | VM_WRITE:
+		return PAGE_COPY_READ_EXEC;
+	case VM_SHARED:
+		return PAGE_NONE;
+	case VM_SHARED | VM_READ:
+		return PAGE_READ;
+	case VM_SHARED | VM_WRITE:
+		return PAGE_SHARED;
+	case VM_SHARED | VM_READ | VM_WRITE:
+		return PAGE_SHARED;
+	case VM_SHARED | VM_EXEC:
+		return PAGE_EXEC;
+	case VM_SHARED | VM_EXEC | VM_READ:
+		return PAGE_READ_EXEC;
+	case VM_SHARED | VM_EXEC | VM_WRITE:
+		return PAGE_SHARED_EXEC;
+	case VM_SHARED | VM_EXEC | VM_READ | VM_WRITE:
+		return PAGE_SHARED_EXEC;
+	default:
+		BUILD_BUG();
+	}
+}
+EXPORT_SYMBOL(vm_get_page_prot);
-- 
2.25.1