[3.11.y.z extended stable] Patch "arm64: Move PTE_PROT_NONE higher up" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    arm64: Move PTE_PROT_NONE higher up

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From cb7b5f3963f6a31bc487a06d4b1e4f15fe745c63 Mon Sep 17 00:00:00 2001
From: Catalin Marinas <catalin.marinas at arm.com>
Date: Wed, 27 Nov 2013 16:59:27 +0000
Subject: arm64: Move PTE_PROT_NONE higher up

commit 3676f9ef5481d614f8c5c857f5319755be248268 upstream.

PTE_PROT_NONE means that a pte is present but does not have any
read/write attributes. However, setting the memory type like
pgprot_writecombine() is allowed and such bits overlap with
PTE_PROT_NONE. This causes mmap/munmap issues in drivers that change the
vma->vm_pg_prot on PROT_NONE mappings.

This patch reverts the PTE_FILE/PTE_PROT_NONE shift in commit
59911ca4325d (ARM64: mm: Move PTE_PROT_NONE bit) and moves PTE_PROT_NONE
together with the other software bits.

Signed-off-by: Steve Capper <steve.capper at linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
Tested-by: Steve Capper <steve.capper at linaro.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/arm64/include/asm/pgtable.h | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index f0bebc5..0b27b65 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -25,10 +25,11 @@
  * Software defined PTE bits definition.
  */
 #define PTE_VALID		(_AT(pteval_t, 1) << 0)
-#define PTE_PROT_NONE		(_AT(pteval_t, 1) << 2)	/* only when !PTE_VALID */
-#define PTE_FILE		(_AT(pteval_t, 1) << 3)	/* only when !pte_present() */
+#define PTE_FILE		(_AT(pteval_t, 1) << 2)	/* only when !pte_present() */
 #define PTE_DIRTY		(_AT(pteval_t, 1) << 55)
 #define PTE_SPECIAL		(_AT(pteval_t, 1) << 56)
+				/* bit 57 for PMD_SECT_SPLITTING */
+#define PTE_PROT_NONE		(_AT(pteval_t, 1) << 58) /* only when !PTE_VALID */

 /*
  * VMALLOC and SPARSEMEM_VMEMMAP ranges.
@@ -357,18 +358,20 @@ extern pgd_t idmap_pg_dir[PTRS_PER_PGD];

 /*
  * Encode and decode a swap entry:
- *	bits 0, 2:	present (must both be zero)
- *	bit  3:		PTE_FILE
- *	bits 4-8:	swap type
- *	bits 9-63:	swap offset
+ *	bits 0-1:	present (must be zero)
+ *	bit  2:		PTE_FILE
+ *	bits 3-8:	swap type
+ *	bits 9-57:	swap offset
  */
-#define __SWP_TYPE_SHIFT	4
+#define __SWP_TYPE_SHIFT	3
 #define __SWP_TYPE_BITS		6
+#define __SWP_OFFSET_BITS	49
 #define __SWP_TYPE_MASK		((1 << __SWP_TYPE_BITS) - 1)
 #define __SWP_OFFSET_SHIFT	(__SWP_TYPE_BITS + __SWP_TYPE_SHIFT)
+#define __SWP_OFFSET_MASK	((1UL << __SWP_OFFSET_BITS) - 1)

 #define __swp_type(x)		(((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK)
-#define __swp_offset(x)		((x).val >> __SWP_OFFSET_SHIFT)
+#define __swp_offset(x)		(((x).val >> __SWP_OFFSET_SHIFT) & __SWP_OFFSET_MASK)
 #define __swp_entry(type,offset) ((swp_entry_t) { ((type) << __SWP_TYPE_SHIFT) | ((offset) << __SWP_OFFSET_SHIFT) })

 #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
@@ -382,15 +385,15 @@ extern pgd_t idmap_pg_dir[PTRS_PER_PGD];

 /*
  * Encode and decode a file entry:
- *	bits 0, 2:	present (must both be zero)
- *	bit  3:		PTE_FILE
- *	bits 4-63:	file offset / PAGE_SIZE
+ *	bits 0-1:	present (must be zero)
+ *	bit  2:		PTE_FILE
+ *	bits 3-57:	file offset / PAGE_SIZE
  */
 #define pte_file(pte)		(pte_val(pte) & PTE_FILE)
-#define pte_to_pgoff(x)		(pte_val(x) >> 4)
-#define pgoff_to_pte(x)		__pte(((x) << 4) | PTE_FILE)
+#define pte_to_pgoff(x)		(pte_val(x) >> 3)
+#define pgoff_to_pte(x)		__pte(((x) << 3) | PTE_FILE)

-#define PTE_FILE_MAX_BITS	60
+#define PTE_FILE_MAX_BITS	55

 extern int kern_addr_valid(unsigned long addr);

--
1.8.3.2