Commit 1ab947de authored by Martin Schwidefsky's avatar Martin Schwidefsky Committed by Martin Schwidefsky
Browse files

[S390] fault handler access flags check. 



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

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 50d7280d

arch/s390/mm/fault.c

+13 −17
Original line number Diff line number Diff line
@@ -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)))

		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))

	if (unlikely(!(vma->vm_flags & access)))

		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);

}