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[/] [or1k/] [trunk/] [uclinux/] [uClinux-2.0.x/] [arch/] [mips/] [mm/] [fault.c] - Rev 1765
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/* * arch/mips/mm/fault.c * * Copyright (C) 1995 by Ralf Baechle */ #include <linux/signal.h> #include <linux/sched.h> #include <linux/head.h> #include <linux/kernel.h> #include <linux/errno.h> #include <linux/string.h> #include <linux/types.h> #include <linux/ptrace.h> #include <linux/mman.h> #include <linux/mm.h> #include <asm/system.h> #include <asm/segment.h> #include <asm/pgtable.h> extern void die_if_kernel(char *, struct pt_regs *, long); /* * This routine handles page faults. It determines the address, * and the problem, and then passes it off to one of the appropriate * routines. */ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long writeaccess, unsigned long address) { struct vm_area_struct * vma; #if 0 printk("do_page_fault() #1: %s %08lx (epc == %08lx, ra == %08lx)\n", writeaccess ? "writeaccess to" : "readaccess from", address, regs->cp0_epc, regs->reg31); #endif vma = find_vma(current, address); if (!vma) goto bad_area; if (vma->vm_start <= address) goto good_area; if (!(vma->vm_flags & VM_GROWSDOWN)) 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: if (writeaccess) { if (!(vma->vm_flags & VM_WRITE)) goto bad_area; } else { if (!(vma->vm_flags & (VM_READ | VM_EXEC))) goto bad_area; } handle_mm_fault(vma, address, writeaccess); /* FIXME: This flushes the cache far to often */ sys_cacheflush(address, PAGE_SIZE, BCACHE); 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: if (user_mode(regs)) { current->tss.cp0_badvaddr = address; current->tss.error_code = writeaccess; send_sig(SIGSEGV, current, 1); return; } /* * Oops. The kernel tried to access some bad page. We'll have to * terminate things with extreme prejudice. */ printk(KERN_ALERT "Unable to handle kernel paging request at virtual " "address %08lx\n", address); die_if_kernel("Oops", regs, writeaccess); do_exit(SIGKILL); }