[3.11.y.z extended stable] Patch "ARM: fix booting low-vectors machines" has been added to staging queue

[Luis Henriques]

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

    ARM: fix booting low-vectors machines

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 b728f395ad4a73baf53856781d3266a71b983aaa Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel at arm.linux.org.uk>
Date: Thu, 28 Nov 2013 21:43:40 +0000
Subject: ARM: fix booting low-vectors machines

commit d8aa712c30148ba26fd89a5dc14de95d4c375184 upstream.

Commit f6f91b0d9fd9 (ARM: allow kuser helpers to be removed from the
vector page) required two pages for the vectors code.  Although the
code setting up the initial page tables was updated, the code which
allocates page tables for new processes wasn't, neither was the code
which tears down the mappings.  Fix this.

Fixes: f6f91b0d9fd9 ("ARM: allow kuser helpers to be removed from the vector page")
Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/arm/include/asm/pgtable.h | 2 +-
 arch/arm/mm/mmap.c             | 2 +-
 arch/arm/mm/pgd.c              | 3 ++-
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index 04aeb02..3b5753b 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -61,7 +61,7 @@ extern void __pgd_error(const char *file, int line, pgd_t);
  * mapping to be mapped at.  This is particularly important for
  * non-high vector CPUs.
  */
-#define FIRST_USER_ADDRESS	PAGE_SIZE
+#define FIRST_USER_ADDRESS	(PAGE_SIZE * 2)

 /*
  * Use TASK_SIZE as the ceiling argument for free_pgtables() and
diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index 0c63562..304661d 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -146,7 +146,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,

 	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 	info.length = len;
-	info.low_limit = PAGE_SIZE;
+	info.low_limit = FIRST_USER_ADDRESS;
 	info.high_limit = mm->mmap_base;
 	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
 	info.align_offset = pgoff << PAGE_SHIFT;
diff --git a/arch/arm/mm/pgd.c b/arch/arm/mm/pgd.c
index 0acb089..1046b37 100644
--- a/arch/arm/mm/pgd.c
+++ b/arch/arm/mm/pgd.c
@@ -87,7 +87,8 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
 		init_pud = pud_offset(init_pgd, 0);
 		init_pmd = pmd_offset(init_pud, 0);
 		init_pte = pte_offset_map(init_pmd, 0);
-		set_pte_ext(new_pte, *init_pte, 0);
+		set_pte_ext(new_pte + 0, init_pte[0], 0);
+		set_pte_ext(new_pte + 1, init_pte[1], 0);
 		pte_unmap(init_pte);
 		pte_unmap(new_pte);
 	}
--
1.8.3.2