327 строки
8.0 KiB
C
327 строки
8.0 KiB
C
/*
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* linux/arch/frv/mm/fault.c
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*
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* Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
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* - Written by David Howells (dhowells@redhat.com)
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* - Derived from arch/m68knommu/mm/fault.c
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* - Copyright (C) 1998 D. Jeff Dionne <jeff@lineo.ca>,
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* - Copyright (C) 2000 Lineo, Inc. (www.lineo.com)
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*
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* Based on:
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*
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* linux/arch/m68k/mm/fault.c
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*
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* Copyright (C) 1995 Hamish Macdonald
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*/
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#include <linux/mman.h>
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#include <linux/mm.h>
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#include <linux/kernel.h>
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#include <linux/ptrace.h>
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#include <linux/hardirq.h>
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#include <asm/system.h>
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#include <asm/pgtable.h>
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#include <asm/uaccess.h>
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#include <asm/gdb-stub.h>
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/*****************************************************************************/
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/*
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* This routine handles page faults. It determines the problem, and
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* then passes it off to one of the appropriate routines.
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*/
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asmlinkage void do_page_fault(int datammu, unsigned long esr0, unsigned long ear0)
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{
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struct vm_area_struct *vma;
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struct mm_struct *mm;
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unsigned long _pme, lrai, lrad, fixup;
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siginfo_t info;
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pgd_t *pge;
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pud_t *pue;
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pte_t *pte;
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int write;
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int fault;
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#if 0
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const char *atxc[16] = {
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[0x0] = "mmu-miss", [0x8] = "multi-dat", [0x9] = "multi-sat",
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[0xa] = "tlb-miss", [0xc] = "privilege", [0xd] = "write-prot",
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};
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printk("do_page_fault(%d,%lx [%s],%lx)\n",
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datammu, esr0, atxc[esr0 >> 20 & 0xf], ear0);
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#endif
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mm = current->mm;
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/*
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* We fault-in kernel-space virtual memory on-demand. The
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* 'reference' page table is init_mm.pgd.
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*
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* NOTE! We MUST NOT take any locks for this case. We may
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* be in an interrupt or a critical region, and should
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* only copy the information from the master page table,
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* nothing more.
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*
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* This verifies that the fault happens in kernel space
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* and that the fault was a page not present (invalid) error
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*/
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if (!user_mode(__frame) && (esr0 & ESR0_ATXC) == ESR0_ATXC_AMRTLB_MISS) {
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if (ear0 >= VMALLOC_START && ear0 < VMALLOC_END)
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goto kernel_pte_fault;
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if (ear0 >= PKMAP_BASE && ear0 < PKMAP_END)
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goto kernel_pte_fault;
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}
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info.si_code = SEGV_MAPERR;
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/*
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* If we're in an interrupt or have no user
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* context, we must not take the fault..
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*/
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if (in_atomic() || !mm)
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goto no_context;
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down_read(&mm->mmap_sem);
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vma = find_vma(mm, ear0);
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if (!vma)
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goto bad_area;
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if (vma->vm_start <= ear0)
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goto good_area;
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if (!(vma->vm_flags & VM_GROWSDOWN))
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goto bad_area;
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if (user_mode(__frame)) {
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/*
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* accessing the stack below %esp is always a bug.
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* The "+ 32" is there due to some instructions (like
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* pusha) doing post-decrement on the stack and that
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* doesn't show up until later..
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*/
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if ((ear0 & PAGE_MASK) + 2 * PAGE_SIZE < __frame->sp) {
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#if 0
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printk("[%d] ### Access below stack @%lx (sp=%lx)\n",
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current->pid, ear0, __frame->sp);
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show_registers(__frame);
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printk("[%d] ### Code: [%08lx] %02x %02x %02x %02x %02x %02x %02x %02x\n",
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current->pid,
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__frame->pc,
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((u8*)__frame->pc)[0],
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((u8*)__frame->pc)[1],
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((u8*)__frame->pc)[2],
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((u8*)__frame->pc)[3],
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((u8*)__frame->pc)[4],
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((u8*)__frame->pc)[5],
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((u8*)__frame->pc)[6],
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((u8*)__frame->pc)[7]
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);
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#endif
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goto bad_area;
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}
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}
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if (expand_stack(vma, ear0))
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goto bad_area;
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/*
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* Ok, we have a good vm_area for this memory access, so
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* we can handle it..
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*/
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good_area:
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info.si_code = SEGV_ACCERR;
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write = 0;
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switch (esr0 & ESR0_ATXC) {
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default:
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/* handle write to write protected page */
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case ESR0_ATXC_WP_EXCEP:
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#ifdef TEST_VERIFY_AREA
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if (!(user_mode(__frame)))
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printk("WP fault at %08lx\n", __frame->pc);
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#endif
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if (!(vma->vm_flags & VM_WRITE))
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goto bad_area;
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write = 1;
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break;
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/* handle read from protected page */
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case ESR0_ATXC_PRIV_EXCEP:
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goto bad_area;
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/* handle read, write or exec on absent page
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* - can't support write without permitting read
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* - don't support execute without permitting read and vice-versa
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*/
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case ESR0_ATXC_AMRTLB_MISS:
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if (!(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)))
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goto bad_area;
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break;
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}
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/*
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* If for any reason at all we couldn't handle the fault,
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* make sure we exit gracefully rather than endlessly redo
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* the fault.
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*/
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fault = handle_mm_fault(mm, vma, ear0, write);
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if (unlikely(fault & VM_FAULT_ERROR)) {
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if (fault & VM_FAULT_OOM)
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goto out_of_memory;
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else if (fault & VM_FAULT_SIGBUS)
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goto do_sigbus;
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BUG();
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}
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if (fault & VM_FAULT_MAJOR)
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current->maj_flt++;
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else
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current->min_flt++;
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up_read(&mm->mmap_sem);
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return;
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/*
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* Something tried to access memory that isn't in our memory map..
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* Fix it, but check if it's kernel or user first..
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*/
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bad_area:
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up_read(&mm->mmap_sem);
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/* User mode accesses just cause a SIGSEGV */
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if (user_mode(__frame)) {
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info.si_signo = SIGSEGV;
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info.si_errno = 0;
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/* info.si_code has been set above */
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info.si_addr = (void *) ear0;
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force_sig_info(SIGSEGV, &info, current);
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return;
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}
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no_context:
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/* are we prepared to handle this kernel fault? */
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if ((fixup = search_exception_table(__frame->pc)) != 0) {
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__frame->pc = fixup;
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return;
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}
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/*
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* Oops. The kernel tried to access some bad page. We'll have to
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* terminate things with extreme prejudice.
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*/
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bust_spinlocks(1);
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if (ear0 < PAGE_SIZE)
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printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
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else
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printk(KERN_ALERT "Unable to handle kernel paging request");
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printk(" at virtual addr %08lx\n", ear0);
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printk(" PC : %08lx\n", __frame->pc);
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printk(" EXC : esr0=%08lx ear0=%08lx\n", esr0, ear0);
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asm("lrai %1,%0,#1,#0,#0" : "=&r"(lrai) : "r"(ear0));
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asm("lrad %1,%0,#1,#0,#0" : "=&r"(lrad) : "r"(ear0));
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printk(KERN_ALERT " LRAI: %08lx\n", lrai);
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printk(KERN_ALERT " LRAD: %08lx\n", lrad);
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__break_hijack_kernel_event();
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pge = pgd_offset(current->mm, ear0);
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pue = pud_offset(pge, ear0);
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_pme = pue->pue[0].ste[0];
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printk(KERN_ALERT " PGE : %8p { PME %08lx }\n", pge, _pme);
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if (_pme & xAMPRx_V) {
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unsigned long dampr, damlr, val;
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asm volatile("movsg dampr2,%0 ! movgs %2,dampr2 ! movsg damlr2,%1"
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: "=&r"(dampr), "=r"(damlr)
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: "r" (_pme | xAMPRx_L|xAMPRx_SS_16Kb|xAMPRx_S|xAMPRx_C|xAMPRx_V)
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);
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pte = (pte_t *) damlr + __pte_index(ear0);
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val = pte_val(*pte);
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asm volatile("movgs %0,dampr2" :: "r" (dampr));
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printk(KERN_ALERT " PTE : %8p { %08lx }\n", pte, val);
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}
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die_if_kernel("Oops\n");
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do_exit(SIGKILL);
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/*
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* We ran out of memory, or some other thing happened to us that made
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* us unable to handle the page fault gracefully.
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*/
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out_of_memory:
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up_read(&mm->mmap_sem);
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printk("VM: killing process %s\n", current->comm);
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if (user_mode(__frame))
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do_group_exit(SIGKILL);
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goto no_context;
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do_sigbus:
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up_read(&mm->mmap_sem);
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/*
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* Send a sigbus, regardless of whether we were in kernel
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* or user mode.
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*/
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info.si_signo = SIGBUS;
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info.si_errno = 0;
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info.si_code = BUS_ADRERR;
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info.si_addr = (void *) ear0;
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force_sig_info(SIGBUS, &info, current);
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/* Kernel mode? Handle exceptions or die */
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if (!user_mode(__frame))
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goto no_context;
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return;
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/*
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* The fault was caused by a kernel PTE (such as installed by vmalloc or kmap)
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*/
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kernel_pte_fault:
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{
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/*
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* Synchronize this task's top level page-table
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* with the 'reference' page table.
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*
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* Do _not_ use "tsk" here. We might be inside
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* an interrupt in the middle of a task switch..
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*/
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int index = pgd_index(ear0);
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pgd_t *pgd, *pgd_k;
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pud_t *pud, *pud_k;
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pmd_t *pmd, *pmd_k;
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pte_t *pte_k;
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pgd = (pgd_t *) __get_TTBR();
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pgd = (pgd_t *)__va(pgd) + index;
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pgd_k = ((pgd_t *)(init_mm.pgd)) + index;
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if (!pgd_present(*pgd_k))
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goto no_context;
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//set_pgd(pgd, *pgd_k); /////// gcc ICE's on this line
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pud_k = pud_offset(pgd_k, ear0);
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if (!pud_present(*pud_k))
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goto no_context;
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pmd_k = pmd_offset(pud_k, ear0);
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if (!pmd_present(*pmd_k))
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goto no_context;
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pud = pud_offset(pgd, ear0);
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pmd = pmd_offset(pud, ear0);
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set_pmd(pmd, *pmd_k);
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pte_k = pte_offset_kernel(pmd_k, ear0);
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if (!pte_present(*pte_k))
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goto no_context;
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return;
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}
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} /* end do_page_fault() */
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