Gitweb:     http://git.kernel.org/linus/d374bf14a5ff18133bd6a6cc00f189949f7ba8fb
Commit:     d374bf14a5ff18133bd6a6cc00f189949f7ba8fb
Parent:     bf4569922b97824f33e5d08d0bbe4b34fe43e4cd
Author:     Russell King <rmk+kernel@arm.linux.org.uk>
AuthorDate: Sun Sep 20 12:53:01 2009 +0100
Committer:  Russell King <rmk+kernel@arm.linux.org.uk>
CommitDate: Sun Sep 20 16:53:40 2009 +0100

    ARM: Separate out access error checking
    
    Since we get notified separately about prefetch aborts, which may be
    permission faults, we need to check for appropriate access permissions
    when handling a fault.  This patch prepares us for doing this by
    separating out the access error checking.
    
    Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
 arch/arm/mm/fault.c |   33 ++++++++++++++++++++++-----------
 1 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index b8b3bb4..b7ce07d 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -194,18 +194,33 @@ void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 #define VM_FAULT_BADMAP		0x010000
 #define VM_FAULT_BADACCESS	0x020000
 
-static int
+/*
+ * Check that the permissions on the VMA allow for the fault which occurred.
+ * If we encountered a write fault, we must have write permission, otherwise
+ * we allow any permission.
+ */
+static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
+{
+	unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
+
+	if (fsr & FSR_WRITE)
+		mask = VM_WRITE;
+
+	return vma->vm_flags & mask ? false : true;
+}
+
+static int __kprobes
 __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
 		struct task_struct *tsk)
 {
 	struct vm_area_struct *vma;
-	int fault, mask;
+	int fault;
 
 	vma = find_vma(mm, addr);
 	fault = VM_FAULT_BADMAP;
-	if (!vma)
+	if (unlikely(!vma))
 		goto out;
-	if (vma->vm_start > addr)
+	if (unlikely(vma->vm_start > ...
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