diff mbox series

[V2,02/30] mm/mmap: Clarify protection_map[] indices

Message ID	1645425519-9034-3-git-send-email-anshuman.khandual@arm.com (mailing list archive)
State	New
Headers	show Return-Path: <owner-linux-mm@kvack.org> From: Anshuman Khandual <anshuman.khandual@arm.com> To: linux-mm@kvack.org, akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, Anshuman Khandual <anshuman.khandual@arm.com>, Christoph Hellwig <hch@infradead.org>, linux-arch@vger.kernel.org Subject: [PATCH V2 02/30] mm/mmap: Clarify protection_map[] indices Date: Mon, 21 Feb 2022 12:08:11 +0530 Message-Id: <1645425519-9034-3-git-send-email-anshuman.khandual@arm.com> In-Reply-To: <1645425519-9034-1-git-send-email-anshuman.khandual@arm.com> References: <1645425519-9034-1-git-send-email-anshuman.khandual@arm.com> Sender: owner-linux-mm@kvack.org Precedence: bulk
Series	mm/mmap: Drop protection_map[] and platform's __SXXX/__PXXX requirements \| expand [V2,00/30] mm/mmap: Drop protection_map[] and platform's __SXXX/__PXXX requirements [V2,01/30] mm/debug_vm_pgtable: Drop protection_map[] usage [V2,02/30] mm/mmap: Clarify protection_map[] indices [V2,03/30] mm/mmap: Add new config ARCH_HAS_VM_GET_PAGE_PROT [V2,04/30] powerpc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,05/30] arm64/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,06/30] sparc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,07/30] mips/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,08/30] m68k/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,09/30] arm/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,10/30] x86/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,11/30] mm/mmap: Drop protection_map[] [V2,12/30] mm/mmap: Drop arch_filter_pgprot() [V2,13/30] mm/mmap: Drop arch_vm_get_page_pgprot() [V2,14/30] s390/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,15/30] riscv/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,16/30] alpha/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,17/30] sh/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,18/30] arc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,19/30] csky/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,20/30] extensa/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,21/30] parisc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,22/30] openrisc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,23/30] um/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,24/30] microblaze/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,25/30] nios2/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,26/30] hexagon/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,27/30] nds32/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,28/30] ia64/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT [V2,29/30] mm/mmap: Drop generic vm_get_page_prot() [V2,30/30] mm/mmap: Drop ARCH_HAS_VM_GET_PAGE_PROT

Commit Message

Anshuman Khandual Feb. 21, 2022, 6:38 a.m. UTC

protection_map[] maps vm_flags access combinations into page protection
value as defined by the platform via __PXXX and __SXXX macros. The array
indices in protection_map[], represents vm_flags access combinations but
it's not very intuitive to derive. This makes it clear and explicit.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 mm/mmap.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff mbox series

Patch

diff --git a/mm/mmap.c b/mm/mmap.c
index 1e8fdb0b51ed..670c68f5fbf1 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -102,8 +102,22 @@  static void unmap_region(struct mm_struct *mm,
  *								x: (yes) yes
  */
 pgprot_t protection_map[16] __ro_after_init = {
-	__P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
-	__S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
+	[VM_NONE]					= __P000,
+	[VM_READ]					= __P001,
+	[VM_WRITE]					= __P010,
+	[VM_WRITE | VM_READ]				= __P011,
+	[VM_EXEC]					= __P100,
+	[VM_EXEC | VM_READ]				= __P101,
+	[VM_EXEC | VM_WRITE]				= __P110,
+	[VM_EXEC | VM_WRITE | VM_READ]			= __P111,
+	[VM_SHARED]					= __S000,
+	[VM_SHARED | VM_READ]				= __S001,
+	[VM_SHARED | VM_WRITE]				= __S010,
+	[VM_SHARED | VM_WRITE | VM_READ]		= __S011,
+	[VM_SHARED | VM_EXEC]				= __S100,
+	[VM_SHARED | VM_EXEC | VM_READ]			= __S101,
+	[VM_SHARED | VM_EXEC | VM_WRITE]		= __S110,
+	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= __S111
 };
 
 #ifndef CONFIG_ARCH_HAS_FILTER_PGPROT