+ mm-mmap-clarify-protection_map-indices.patch added to -mm tree

* + mm-mmap-clarify-protection_map-indices.patch added to -mm tree
@ 2022-04-04 19:15 Andrew Morton
  0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2022-04-04 19:15 UTC (permalink / raw)
  To: mm-commits, hch, anshuman.khandual, akpm


The patch titled
     Subject: mm/mmap: clarify protection_map[] indices
has been added to the -mm tree.  Its filename is
     mm-mmap-clarify-protection_map-indices.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-mmap-clarify-protection_map-indices.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-mmap-clarify-protection_map-indices.patch

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------------------------------------------------------
From: Anshuman Khandual <anshuman.khandual@arm.com>
Subject: mm/mmap: clarify protection_map[] indices

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.

Link: https://lkml.kernel.org/r/20220404031840.588321-3-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mmap.c |   18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

--- a/mm/mmap.c~mm-mmap-clarify-protection_map-indices
+++ a/mm/mmap.c
@@ -102,8 +102,22 @@ static void unmap_region(struct mm_struc
  *								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
_

Patches currently in -mm which might be from anshuman.khandual@arm.com are

mm-debug_vm_pgtable-drop-protection_map-usage.patch
mm-mmap-clarify-protection_map-indices.patch


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