[S390] fault handler access flags check.

Simplify the check of the vma->flags in do_exception for the
different fault types.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 0dcfcfb..5a9e9a7 100644 (file)
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -286,7 +286,7 @@ static noinline void do_fault_error(struct pt_regs *regs, long int_code,
  *   11       Page translation     ->  Not present       (nullification)
  *   3b       Region third trans.  ->  Not present       (nullification)
  */
-static inline int do_exception(struct pt_regs *regs, int write,
+static inline int do_exception(struct pt_regs *regs, int access,
                               unsigned long trans_exc_code)
 {
        struct task_struct *tsk;
@@ -337,19 +337,8 @@ static inline int do_exception(struct pt_regs *regs, int write,
         * we can handle it..
         */
        fault = VM_FAULT_BADACCESS;
-#ifdef CONFIG_S390_EXEC_PROTECT
-       if (unlikely((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_SECONDARY &&
-                    (trans_exc_code & 3) == 0 && !(vma->vm_flags & VM_EXEC)))
+       if (unlikely(!(vma->vm_flags & access)))
                goto out_up;
-#endif
-       if (!write) {
-               /* page not present, check vm flags */
-               if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
-                       goto out_up;
-       } else {
-               if (!(vma->vm_flags & VM_WRITE))
-                       goto out_up;
-       }
 
        if (is_vm_hugetlb_page(vma))
                address &= HPAGE_MASK;
@@ -358,7 +347,8 @@ static inline int do_exception(struct pt_regs *regs, int write,
         * make sure we exit gracefully rather than endlessly redo
         * the fault.
         */
-       fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
+       fault = handle_mm_fault(mm, vma, address,
+                               (access == VM_WRITE) ? FAULT_FLAG_WRITE : 0);
        if (unlikely(fault & VM_FAULT_ERROR))
                goto out_up;
 
@@ -399,7 +389,7 @@ void __kprobes do_protection_exception(struct pt_regs *regs, long int_code)
                do_low_address(regs, int_code, trans_exc_code);
                return;
        }
-       fault = do_exception(regs, 1, trans_exc_code);
+       fault = do_exception(regs, VM_WRITE, trans_exc_code);
        if (unlikely(fault))
                do_fault_error(regs, 4, trans_exc_code, fault);
 }
@@ -407,9 +397,15 @@ void __kprobes do_protection_exception(struct pt_regs *regs, long int_code)
 void __kprobes do_dat_exception(struct pt_regs *regs, long int_code)
 {
        unsigned long trans_exc_code = S390_lowcore.trans_exc_code;
-       int fault;
+       int access, fault;
 
-       fault = do_exception(regs, 0, trans_exc_code);
+       access = VM_READ | VM_EXEC | VM_WRITE;
+#ifdef CONFIG_S390_EXEC_PROTECT
+       if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_SECONDARY &&
+           (trans_exc_code & 3) == 0)
+               access = VM_EXEC;
+#endif
+       fault = do_exception(regs, access, trans_exc_code);
        if (unlikely(fault))
                do_fault_error(regs, int_code & 255, trans_exc_code, fault);
 }