From 1ab947de293f43812276b60cf9fa21127e7a5bb2 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Mon, 7 Dec 2009 12:51:46 +0100 Subject: [PATCH] [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 --- arch/s390/mm/fault.c | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-) diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 0dcfcfb5b5be..5a9e9a77dc16 100644 --- 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); } -- GitLab