[PATCH V6 15/26] nios2/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

From: Anshuman Khandual
Date: Thu Jun 30 2022 - 01:20:29 EST


This enables ARCH_HAS_VM_GET_PAGE_PROT on the platform and exports standard
vm_get_page_prot() implementation via DECLARE_VM_GET_PAGE_PROT, which looks
up a private and static protection_map[] array. Subsequently all __SXXX and
__PXXX macros can be dropped which are no longer needed.

Cc: Dinh Nguyen <dinguyen@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
arch/nios2/Kconfig | 1 +
arch/nios2/include/asm/pgtable.h | 16 ----------------
arch/nios2/mm/init.c | 20 ++++++++++++++++++++
3 files changed, 21 insertions(+), 16 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..470516d4555e 100644
--- a/arch/nios2/include/asm/pgtable.h
+++ b/arch/nios2/include/asm/pgtable.h
@@ -40,24 +40,8 @@ struct mm_struct;
*/

/* 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..ae24687d12ad 100644
--- a/arch/nios2/mm/init.c
+++ b/arch/nios2/mm/init.c
@@ -124,3 +124,23 @@ const char *arch_vma_name(struct vm_area_struct *vma)
{
return (vma->vm_start == KUSER_BASE) ? "[kuser]" : NULL;
}
+
+static const pgprot_t protection_map[16] = {
+ [VM_NONE] = MKP(0, 0, 0),
+ [VM_READ] = MKP(0, 0, 1),
+ [VM_WRITE] = MKP(0, 0, 0),
+ [VM_WRITE | VM_READ] = MKP(0, 0, 1),
+ [VM_EXEC] = MKP(1, 0, 0),
+ [VM_EXEC | VM_READ] = MKP(1, 0, 1),
+ [VM_EXEC | VM_WRITE] = MKP(1, 0, 0),
+ [VM_EXEC | VM_WRITE | VM_READ] = MKP(1, 0, 1),
+ [VM_SHARED] = MKP(0, 0, 0),
+ [VM_SHARED | VM_READ] = MKP(0, 0, 1),
+ [VM_SHARED | VM_WRITE] = MKP(0, 1, 0),
+ [VM_SHARED | VM_WRITE | VM_READ] = MKP(0, 1, 1),
+ [VM_SHARED | VM_EXEC] = MKP(1, 0, 0),
+ [VM_SHARED | VM_EXEC | VM_READ] = MKP(1, 0, 1),
+ [VM_SHARED | VM_EXEC | VM_WRITE] = MKP(1, 1, 0),
+ [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = MKP(1, 1, 1)
+};
+DECLARE_VM_GET_PAGE_PROT
--
2.25.1