[PATCH V4 1/7] mm/mmap: Add new config ARCH_HAS_VM_GET_PAGE_PROT

[Anshuman Khandual <anshuman.khandual@arm.com>]

Add a new config ARCH_HAS_VM_GET_PAGE_PROT, which when subscribed enables a
given platform to define its own vm_get_page_prot() but still utilizing the
generic protection_map[] array.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 mm/Kconfig | 3 +++
 mm/mmap.c  | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/mm/Kconfig b/mm/Kconfig
index 034d87953600..b1f7624276f8 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -765,6 +765,9 @@ config ARCH_HAS_CURRENT_STACK_POINTER
 config ARCH_HAS_FILTER_PGPROT
 	bool
 
+config ARCH_HAS_VM_GET_PAGE_PROT
+	bool
+
 config ARCH_HAS_PTE_DEVMAP
 	bool
 
diff --git a/mm/mmap.c b/mm/mmap.c
index 3aa839f81e63..87cb2eaf7e1a 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -106,6 +106,7 @@ pgprot_t protection_map[16] __ro_after_init = {
 	__S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
 };
 
+#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
 #ifndef CONFIG_ARCH_HAS_FILTER_PGPROT
 static inline pgprot_t arch_filter_pgprot(pgprot_t prot)
 {
@@ -122,6 +123,7 @@ pgprot_t vm_get_page_prot(unsigned long vm_flags)
 	return arch_filter_pgprot(ret);
 }
 EXPORT_SYMBOL(vm_get_page_prot);
+#endif	/* CONFIG_ARCH_HAS_VM_GET_PAGE_PROT */
 
 static pgprot_t vm_pgprot_modify(pgprot_t oldprot, unsigned long vm_flags)
 {
-- 
2.25.1