arc/mm: enable ARCH_HAS_VM_GET_PAGE_PROT

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.

Link: https://lkml.kernel.org/r/20220711070600.2378316-23-anshuman.khandual@arm.comSigned-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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

arch/arc/include/asm/pgtable-bits-arcv2.h

@@ -72,24 +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__
 
 #define pte_write(pte)		(pte_val(pte) & _PAGE_WRITE)

arch/arc/mm/mmap.c

@@ -74,3 +74,23 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	info.align_offset = pgoff << PAGE_SHIFT;
 	return vm_unmapped_area(&info);
 }
+
+static const pgprot_t protection_map[16] = {
+	[VM_NONE]					= PAGE_U_NONE,
+	[VM_READ]					= PAGE_U_R,
+	[VM_WRITE]					= PAGE_U_R,
+	[VM_WRITE | VM_READ]				= PAGE_U_R,
+	[VM_EXEC]					= PAGE_U_X_R,
+	[VM_EXEC | VM_READ]				= PAGE_U_X_R,
+	[VM_EXEC | VM_WRITE]				= PAGE_U_X_R,
+	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_U_X_R,
+	[VM_SHARED]					= PAGE_U_NONE,
+	[VM_SHARED | VM_READ]				= PAGE_U_R,
+	[VM_SHARED | VM_WRITE]				= PAGE_U_W_R,
+	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_U_W_R,
+	[VM_SHARED | VM_EXEC]				= PAGE_U_X_R,
+	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_U_X_R,
+	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_U_X_W_R,
+	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_U_X_W_R
+};
+DECLARE_VM_GET_PAGE_PROT