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[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>
This commit is contained in:
Martin Schwidefsky 2009-12-07 12:51:46 +01:00 коммит произвёл Martin Schwidefsky
Родитель 50d7280d43
Коммит 1ab947de29
1 изменённых файлов: 13 добавлений и 17 удалений
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30
arch/s390/mm/fault.c
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@ -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);
}