[PATCH V2 18/30] arc/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: Vineet Gupta <vgupta at kernel.org>
Cc: linux-snps-arc at lists.infradead.org
Cc: linux-kernel at vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual at arm.com>
---
 arch/arc/Kconfig                          |  1 +
 arch/arc/include/asm/pgtable-bits-arcv2.h | 17 ----------
 arch/arc/mm/mmap.c                        | 41 +++++++++++++++++++++++
 3 files changed, 42 insertions(+), 17 deletions(-)

diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 3c2a4753d09b..78ff0644b343 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -13,6 +13,7 @@ config ARC
 	select ARCH_HAS_SETUP_DMA_OPS
 	select ARCH_HAS_SYNC_DMA_FOR_CPU
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
+	select ARCH_HAS_VM_GET_PAGE_PROT
 	select ARCH_SUPPORTS_ATOMIC_RMW if ARC_HAS_LLSC
 	select ARCH_32BIT_OFF_T
 	select BUILDTIME_TABLE_SORT
diff --git a/arch/arc/include/asm/pgtable-bits-arcv2.h b/arch/arc/include/asm/pgtable-bits-arcv2.h
index 183d23bc1e00..798308f4dbad 100644
--- a/arch/arc/include/asm/pgtable-bits-arcv2.h
+++ b/arch/arc/include/asm/pgtable-bits-arcv2.h
@@ -72,23 +72,6 @@
  *     This is to enable COW mechanism
  */
 	/* xwr */
-#define __P000  PAGE_U_NONE
-#define __P001  PAGE_U_R
-#define __P010  PAGE_U_R	/* Pvt-W => !W */
-#define __P011  PAGE_U_R	/* Pvt-W => !W */
-#define __P100  PAGE_U_X_R	/* X => R */
-#define __P101  PAGE_U_X_R
-#define __P110  PAGE_U_X_R	/* Pvt-W => !W and X => R */
-#define __P111  PAGE_U_X_R	/* Pvt-W => !W */
-
-#define __S000  PAGE_U_NONE
-#define __S001  PAGE_U_R
-#define __S010  PAGE_U_W_R	/* W => R */
-#define __S011  PAGE_U_W_R
-#define __S100  PAGE_U_X_R	/* X => R */
-#define __S101  PAGE_U_X_R
-#define __S110  PAGE_U_X_W_R	/* X => R */
-#define __S111  PAGE_U_X_W_R
 
 #ifndef __ASSEMBLY__
 
diff --git a/arch/arc/mm/mmap.c b/arch/arc/mm/mmap.c
index 722d26b94307..d286894d7359 100644
--- a/arch/arc/mm/mmap.c
+++ b/arch/arc/mm/mmap.c
@@ -74,3 +74,44 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	info.align_offset = pgoff << PAGE_SHIFT;
 	return vm_unmapped_area(&info);
 }
+
+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_U_NONE;
+	case VM_READ:
+	/* Pvt-W => !W */
+	case VM_WRITE:
+	/* Pvt-W => !W */
+	case VM_WRITE | VM_READ:
+		return PAGE_U_R;
+	/* X => R */
+	case VM_EXEC:
+	case VM_EXEC | VM_READ:
+	 /* Pvt-W => !W and X => R */
+	case VM_EXEC | VM_WRITE:
+	 /* Pvt-W => !W */
+	case VM_EXEC | VM_WRITE | VM_READ:
+		return PAGE_U_X_R;
+	case VM_SHARED:
+		return PAGE_U_NONE;
+	case VM_SHARED | VM_READ:
+		return PAGE_U_R;
+	/* W => R */
+	case VM_SHARED | VM_WRITE:
+	case VM_SHARED | VM_WRITE | VM_READ:
+		return PAGE_U_W_R;
+	 /* X => R */
+	case VM_SHARED | VM_EXEC:
+	case VM_SHARED | VM_EXEC | VM_READ:
+		return PAGE_U_X_R;
+	/* X => R */
+	case VM_SHARED | VM_EXEC | VM_WRITE:
+	case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ:
+		return PAGE_U_X_W_R;
+	default:
+		BUILD_BUG();
+	}
+}
+EXPORT_SYMBOL(vm_get_page_prot);
-- 
2.25.1