ARC: mm: do_page_fault refactor #3: tidyup vma access permission code (85c5e337) · Commits · 戴 / test

arch/arc/mm/fault.c

+21 −18

Original line number	Diff line number	Diff line
		@@ -64,9 +64,9 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
		struct task_struct *tsk = current;
		struct mm_struct *mm = tsk->mm;
		int si_code = SEGV_MAPERR;
		unsigned int write = 0, exec = 0, mask;
		vm_fault_t fault;
		int write = regs->ecr_cause & ECR_C_PROTV_STORE; /* ST/EX */
		unsigned int flags = FAULT_FLAG_ALLOW_RETRY \| FAULT_FLAG_KILLABLE;
		unsigned int flags;

		/*
		* NOTE! We MUST NOT take any locks for this case. We may
		@@ -88,8 +88,18 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
		if (faulthandler_disabled() \|\| !mm)
		goto no_context;

		if (regs->ecr_cause & ECR_C_PROTV_STORE) /* ST/EX */
		write = 1;
		else if ((regs->ecr_vec == ECR_V_PROTV) &&
		(regs->ecr_cause == ECR_C_PROTV_INST_FETCH))
		exec = 1;

		flags = FAULT_FLAG_ALLOW_RETRY \| FAULT_FLAG_KILLABLE;
		if (user_mode(regs))
		flags \|= FAULT_FLAG_USER;
		if (write)
		flags \|= FAULT_FLAG_WRITE;

		retry:
		down_read(&mm->mmap_sem);

		@@ -102,23 +112,16 @@ retry:
		}

		/*
		* Ok, we have a good vm_area for this memory access, so
		* we can handle it..
		* vm_area is good, now check permissions for this memory access
		*/
		si_code = SEGV_ACCERR;

		/* Handle protection violation, execute on heap or stack */
		mask = VM_READ;
		if (write)
		mask = VM_WRITE;
		if (exec)
		mask = VM_EXEC;

		if ((regs->ecr_vec == ECR_V_PROTV) &&
		(regs->ecr_cause == ECR_C_PROTV_INST_FETCH))
		goto bad_area;

		if (write) {
		if (!(vma->vm_flags & VM_WRITE))
		goto bad_area;
		flags \|= FAULT_FLAG_WRITE;
		} else {
		if (!(vma->vm_flags & (VM_READ \| VM_EXEC)))
		if (!(vma->vm_flags & mask)) {
		si_code = SEGV_ACCERR;
		goto bad_area;
		}

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