tsk->thread.cr2 = address; tsk->thread.trap_no = 14; tsk->thread.error_code = error_code; 
fastcall void do_page_fault(struct pt_regs *regs, unsigned long error_code){	struct task_struct *tsk;	struct mm_struct *mm;	struct vm_area_struct * vma;	unsigned long address;	unsigned long page;	int write;	siginfo_t info;	/* get the address */	__asm__("movl %%cr2,%0":"=r" (address));	if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,					SIGSEGV) == NOTIFY_STOP)		return;	/* It's safe to allow irq's after cr2 has been saved */	if (regs->eflags & (X86_EFLAGS_IF|VM_MASK))		local_irq_enable();	tsk = current;	info.si_code = SEGV_MAPERR;	/*	 * We fault-in kernel-space virtual memory on-demand. The	 * 'reference' page table is init_mm.pgd.	 *	 * NOTE! We MUST NOT take any locks for this case. We may	 * be in an interrupt or a critical region, and should	 * only copy the information from the master page table,	 * nothing more.	 *	 * This verifies that the fault happens in kernel space	 * (error_code & 4) == 0, and that the fault was not a	 * protection error (error_code & 1) == 0.	 */	if (unlikely(address >= TASK_SIZE)) { 		if (!(error_code & 5))			goto vmalloc_fault;		/* 		 * Don't take the mm semaphore here. If we fixup a prefetch		 * fault we could otherwise deadlock.		 */		goto bad_area_nosemaphore;	} 	mm = tsk->mm;	/*	 * If we're in an interrupt, have no user context or are running in an	 * atomic region then we must not take the fault..	 */	if (in_atomic() || !mm)		goto bad_area_nosemaphore;	/* When running in the kernel we expect faults to occur only to	 * addresses in user space.  All other faults represent errors in the	 * kernel and should generate an OOPS.  Unfortunatly, in the case of an	 * erroneous fault occuring in a code path which already holds mmap_sem	 * we will deadlock attempting to validate the fault against the	 * address space.  Luckily the kernel only validly references user	 * space from well defined areas of code, which are listed in the	 * exceptions table.	 *	 * As the vast majority of faults will be valid we will only perform	 * the source reference check when there is a possibilty of a deadlock.	 * Attempt to lock the address space, if we cannot we then validate the	 * source.  If this is invalid we can skip the address space check,	 * thus avoiding the deadlock.	 */	if (!down_read_trylock(&mm->mmap_sem)) {		if ((error_code & 4) == 0 &&		    !search_exception_tables(regs->eip))			goto bad_area_nosemaphore;		down_read(&mm->mmap_sem);	}	vma = find_vma(mm, address);	if (!vma)		goto bad_area;	if (vma->vm_start <= address)		goto good_area;	if (!(vma->vm_flags & VM_GROWSDOWN))		goto bad_area;	if (error_code & 4) {		/*		 * accessing the stack below %esp is always a bug.		 * The "+ 32" is there due to some instructions (like		 * pusha) doing post-decrement on the stack and that		 * doesn't show up until later..		 */		if (address + 32 < regs->esp)			goto bad_area;	}	if (expand_stack(vma, address))		goto bad_area;/* * Ok, we have a good vm_area for this memory access, so * we can handle it.. */good_area:	info.si_code = SEGV_ACCERR;	write = 0;	switch (error_code & 3) {		default:	/* 3: write, present */#ifdef TEST_VERIFY_AREA			if (regs->cs == KERNEL_CS)				printk("WP fault at %08lx\n", regs->eip);#endif			/* fall through */		case 2:		/* write, not present */			if (!(vma->vm_flags & VM_WRITE))				goto bad_area;			write++;			break;		case 1:		/* read, present */			goto bad_area;		case 0:		/* read, not present */			if (!(vma->vm_flags & (VM_READ | VM_EXEC)))				goto bad_area;	} survive:	/*	 * If for any reason at all we couldn't handle the fault,	 * make sure we exit gracefully rather than endlessly redo	 * the fault.	 */	switch (handle_mm_fault(mm, vma, address, write)) {		case VM_FAULT_MINOR:			tsk->min_flt++;			break;		case VM_FAULT_MAJOR:			tsk->maj_flt++;			break;		case VM_FAULT_SIGBUS:			goto do_sigbus;		case VM_FAULT_OOM:			goto out_of_memory;		default:			BUG();	}	/*	 * Did it hit the DOS screen memory VA from vm86 mode?	 */	if (regs->eflags & VM_MASK) {		unsigned long bit = (address - 0xA0000) >> PAGE_SHIFT;		if (bit < 32)			tsk->thread.screen_bitmap |= 1 << bit;	}	up_read(&mm->mmap_sem);	return;/* * Something tried to access memory that isn't in our memory map.. * Fix it, but check if it's kernel or user first.. */bad_area:	up_read(&mm->mmap_sem);bad_area_nosemaphore:	/* User mode accesses just cause a SIGSEGV */	if (error_code & 4) {		/* 		 * Valid to do another page fault here because this one came 		 * from user space.		 */		if (is_prefetch(regs, address, error_code))			return;		tsk->thread.cr2 = address;		/* Kernel addresses are always protection faults */		tsk->thread.error_code = error_code | (address >= TASK_SIZE);		tsk->thread.trap_no = 14;		info.si_signo = SIGSEGV;		info.si_errno = 0;		/* info.si_code has been set above */		info.si_addr = (void __user *)address;		force_sig_info(SIGSEGV, &info, tsk);		return;	}#ifdef CONFIG_X86_F00F_BUG	/*	 * Pentium F0 0F C7 C8 bug workaround.	 */	if (boot_cpu_data.f00f_bug) {		unsigned long nr;				nr = (address - idt_descr.address) >> 3;		if (nr == 6) {			do_invalid_op(regs, 0);			return;		}	}#endifno_context:	/* Are we prepared to handle this kernel fault?  */	if (fixup_exception(regs))		return;	/* 	 * Valid to do another page fault here, because if this fault	 * had been triggered by is_prefetch fixup_exception would have 	 * handled it.	 */ 	if (is_prefetch(regs, address, error_code)) 		return;/* * Oops. The kernel tried to access some bad page. We'll have to * terminate things with extreme prejudice. */	bust_spinlocks(1);#ifdef CONFIG_X86_PAE	if (error_code & 16) {		pte_t *pte = lookup_address(address);		if (pte && pte_present(*pte) && !pte_exec_kernel(*pte))			printk(KERN_CRIT "kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n", current->uid);	}#endif	if (address < PAGE_SIZE)		printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");	else		printk(KERN_ALERT "Unable to handle kernel paging request");	printk(" at virtual address %08lx\n",address);	printk(KERN_ALERT " printing eip:\n");	printk("%08lx\n", regs->eip);	asm("movl %%cr3,%0":"=r" (page));	page = ((unsigned long *) __va(page))[address >> 22];	printk(KERN_ALERT "*pde = %08lx\n", page);	/*	 * We must not directly access the pte in the highpte	 * case, the page table might be allocated in highmem.	 * And lets rather not kmap-atomic the pte, just in case	 * it's allocated already.	 */#ifndef CONFIG_HIGHPTE	if (page & 1) {		page &= PAGE_MASK;		address &= 0x003ff000;		page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT];		printk(KERN_ALERT "*pte = %08lx\n", page);	}#endif	die("Oops", regs, error_code);	bust_spinlocks(0);	do_exit(SIGKILL);/* * We ran out of memory, or some other thing happened to us that made * us unable to handle the page fault gracefully. */out_of_memory:	up_read(&mm->mmap_sem);	if (tsk->pid == 1) {		yield();		down_read(&mm->mmap_sem);		goto survive;	}	printk("VM: killing process %s\n", tsk->comm);	if (error_code & 4)		do_exit(SIGKILL);	goto no_context;do_sigbus:	up_read(&mm->mmap_sem);	/* Kernel mode? Handle exceptions or die */	if (!(error_code & 4))		goto no_context;	/* User space => ok to do another page fault */	if (is_prefetch(regs, address, error_code))		return;	tsk->thread.cr2 = address;	tsk->thread.error_code = error_code;	tsk->thread.trap_no = 14;	info.si_signo = SIGBUS;	info.si_errno = 0;	info.si_code = BUS_ADRERR;	info.si_addr = (void __user *)address;	force_sig_info(SIGBUS, &info, tsk);	return;vmalloc_fault:	{		/*		 * Synchronize this task's top level page-table		 * with the 'reference' page table.		 *		 * Do _not_ use "tsk" here. We might be inside		 * an interrupt in the middle of a task switch..		 */		int index = pgd_index(address);		unsigned long pgd_paddr;		pgd_t *pgd, *pgd_k;		pud_t *pud, *pud_k;		pmd_t *pmd, *pmd_k;		pte_t *pte_k;		asm("movl %%cr3,%0":"=r" (pgd_paddr));		pgd = index + (pgd_t *)__va(pgd_paddr);		pgd_k = init_mm.pgd + index;		if (!pgd_present(*pgd_k))			goto no_context;		/*		 * set_pgd(pgd, *pgd_k); here would be useless on PAE		 * and redundant with the set_pmd() on non-PAE. As would		 * set_pud.		 */		pud = pud_offset(pgd, address);		pud_k = pud_offset(pgd_k, address);		if (!pud_present(*pud_k))			goto no_context;				pmd = pmd_offset(pud, address);		pmd_k = pmd_offset(pud_k, address);		if (!pmd_present(*pmd_k))			goto no_context;		set_pmd(pmd, *pmd_k);		pte_k = pte_offset_kernel(pmd_k, address);		if (!pte_present(*pte_k))			goto no_context;		return;	}}
10457	/local/tlutelli/issta_data/temp/c/2005_temp/2005/10457/4f339ecb30c759f94a29992d4635d9194132b6cf/fault.c/clean/arch/i386/mm/fault.c