RT-AC56 3.0.0.4.374.37 core

[tomato.git] / release / src-rt-6.x.4708 / linux / linux-2.6.36 / arch / parisc / kernel / traps.c

/*
 *  linux/arch/parisc/traps.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 1999, 2000  Philipp Rumpf <prumpf@tux.org>
 */

/*
 * 'Traps.c' handles hardware traps and faults after we have saved some
 * state in 'asm.s'.
 */

#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/timer.h>
#include <linux/delay.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/console.h>
#include <linux/bug.h>

#include <asm/assembly.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/traps.h>
#include <asm/unaligned.h>
#include <asm/atomic.h>
#include <asm/smp.h>
#include <asm/pdc.h>
#include <asm/pdc_chassis.h>
#include <asm/unwind.h>
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>

#include "../math-emu/math-emu.h"       /* for handle_fpe() */

#define PRINT_USER_FAULTS /* (turn this on if you want user faults to be */
                          /*  dumped to the console via printk)          */

#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
DEFINE_SPINLOCK(pa_dbit_lock);
#endif

static void parisc_show_stack(struct task_struct *task, unsigned long *sp,
        struct pt_regs *regs);

static int printbinary(char *buf, unsigned long x, int nbits)
{
        unsigned long mask = 1UL << (nbits - 1);
        while (mask != 0) {
                *buf++ = (mask & x ? '1' : '0');
                mask >>= 1;
        }
        *buf = '\0';

        return nbits;
}

#ifdef CONFIG_64BIT
#define RFMT "%016lx"
#else
#define RFMT "%08lx"
#endif
#define FFMT "%016llx"  /* fpregs are 64-bit always */

#define PRINTREGS(lvl,r,f,fmt,x)        \
        printk("%s%s%02d-%02d  " fmt " " fmt " " fmt " " fmt "\n",      \
                lvl, f, (x), (x+3), (r)[(x)+0], (r)[(x)+1],             \
                (r)[(x)+2], (r)[(x)+3])

static void print_gr(char *level, struct pt_regs *regs)
{
        int i;
        char buf[64];

        printk("%s\n", level);
        printk("%s     YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI\n", level);
        printbinary(buf, regs->gr[0], 32);
        printk("%sPSW: %s %s\n", level, buf, print_tainted());

        for (i = 0; i < 32; i += 4)
                PRINTREGS(level, regs->gr, "r", RFMT, i);
}

static void print_fr(char *level, struct pt_regs *regs)
{
        int i;
        char buf[64];
        struct { u32 sw[2]; } s;

        /* FR are 64bit everywhere. Need to use asm to get the content
         * of fpsr/fper1, and we assume that we won't have a FP Identify
         * in our way, otherwise we're screwed.
         * The fldd is used to restore the T-bit if there was one, as the
         * store clears it anyway.
         * PA2.0 book says "thou shall not use fstw on FPSR/FPERs" - T-Bone */
        asm volatile ("fstd %%fr0,0(%1) \n\t"
                      "fldd 0(%1),%%fr0 \n\t"
                      : "=m" (s) : "r" (&s) : "r0");

        printk("%s\n", level);
        printk("%s      VZOUICununcqcqcqcqcqcrmunTDVZOUI\n", level);
        printbinary(buf, s.sw[0], 32);
        printk("%sFPSR: %s\n", level, buf);
        printk("%sFPER1: %08x\n", level, s.sw[1]);

        /* here we'll print fr0 again, tho it'll be meaningless */
        for (i = 0; i < 32; i += 4)
                PRINTREGS(level, regs->fr, "fr", FFMT, i);
}

void show_regs(struct pt_regs *regs)
{
        int i, user;
        char *level;
        unsigned long cr30, cr31;

        user = user_mode(regs);
        level = user ? KERN_DEBUG : KERN_CRIT;

        print_gr(level, regs);

        for (i = 0; i < 8; i += 4)
                PRINTREGS(level, regs->sr, "sr", RFMT, i);

        if (user)
                print_fr(level, regs);

        cr30 = mfctl(30);
        cr31 = mfctl(31);
        printk("%s\n", level);
        printk("%sIASQ: " RFMT " " RFMT " IAOQ: " RFMT " " RFMT "\n",
               level, regs->iasq[0], regs->iasq[1], regs->iaoq[0], regs->iaoq[1]);
        printk("%s IIR: %08lx    ISR: " RFMT "  IOR: " RFMT "\n",
               level, regs->iir, regs->isr, regs->ior);
        printk("%s CPU: %8d   CR30: " RFMT " CR31: " RFMT "\n",
               level, current_thread_info()->cpu, cr30, cr31);
        printk("%s ORIG_R28: " RFMT "\n", level, regs->orig_r28);

        if (user) {
                printk("%s IAOQ[0]: " RFMT "\n", level, regs->iaoq[0]);
                printk("%s IAOQ[1]: " RFMT "\n", level, regs->iaoq[1]);
                printk("%s RP(r2): " RFMT "\n", level, regs->gr[2]);
        } else {
                printk("%s IAOQ[0]: %pS\n", level, (void *) regs->iaoq[0]);
                printk("%s IAOQ[1]: %pS\n", level, (void *) regs->iaoq[1]);
                printk("%s RP(r2): %pS\n", level, (void *) regs->gr[2]);

                parisc_show_stack(current, NULL, regs);
        }
}


void dump_stack(void)
{
        show_stack(NULL, NULL);
}

EXPORT_SYMBOL(dump_stack);

static void do_show_stack(struct unwind_frame_info *info)
{
        int i = 1;

        printk(KERN_CRIT "Backtrace:\n");
        while (i <= 16) {
                if (unwind_once(info) < 0 || info->ip == 0)
                        break;

                if (__kernel_text_address(info->ip)) {
                        printk(KERN_CRIT " [<" RFMT ">] %pS\n",
                                info->ip, (void *) info->ip);
                        i++;
                }
        }
        printk(KERN_CRIT "\n");
}

static void parisc_show_stack(struct task_struct *task, unsigned long *sp,
        struct pt_regs *regs)
{
        struct unwind_frame_info info;
        struct task_struct *t;

        t = task ? task : current;
        if (regs) {
                unwind_frame_init(&info, t, regs);
                goto show_stack;
        }

        if (t == current) {
                unsigned long sp;

HERE:
                asm volatile ("copy %%r30, %0" : "=r"(sp));
                {
                        struct pt_regs r;

                        memset(&r, 0, sizeof(struct pt_regs));
                        r.iaoq[0] = (unsigned long)&&HERE;
                        r.gr[2] = (unsigned long)__builtin_return_address(0);
                        r.gr[30] = sp;

                        unwind_frame_init(&info, current, &r);
                }
        } else {
                unwind_frame_init_from_blocked_task(&info, t);
        }

show_stack:
        do_show_stack(&info);
}

void show_stack(struct task_struct *t, unsigned long *sp)
{
        return parisc_show_stack(t, sp, NULL);
}

int is_valid_bugaddr(unsigned long iaoq)
{
        return 1;
}

void die_if_kernel(char *str, struct pt_regs *regs, long err)
{
        if (user_mode(regs)) {
                if (err == 0)
                        return; /* STFU */

                printk(KERN_CRIT "%s (pid %d): %s (code %ld) at " RFMT "\n",
                        current->comm, task_pid_nr(current), str, err, regs->iaoq[0]);
#ifdef PRINT_USER_FAULTS
                show_regs(regs);
#endif
                return;
        }

        oops_in_progress = 1;

        oops_enter();

        /* Amuse the user in a SPARC fashion */
        if (err) printk(KERN_CRIT
                        "      _______________________________ \n"
                        "     < Your System ate a SPARC! Gah! >\n"
                        "      ------------------------------- \n"
                        "             \\   ^__^\n"
                        "                 (__)\\       )\\/\\\n"
                        "                  U  ||----w |\n"
                        "                     ||     ||\n");
        
        /* unlock the pdc lock if necessary */
        pdc_emergency_unlock();

        /* maybe the kernel hasn't booted very far yet and hasn't been able 
         * to initialize the serial or STI console. In that case we should 
         * re-enable the pdc console, so that the user will be able to 
         * identify the problem. */
        if (!console_drivers)
                pdc_console_restart();
        
        if (err)
                printk(KERN_CRIT "%s (pid %d): %s (code %ld)\n",
                        current->comm, task_pid_nr(current), str, err);

        /* Wot's wrong wif bein' racy? */
        if (current->thread.flags & PARISC_KERNEL_DEATH) {
                printk(KERN_CRIT "%s() recursion detected.\n", __func__);
                local_irq_enable();
                while (1);
        }
        current->thread.flags |= PARISC_KERNEL_DEATH;

        show_regs(regs);
        dump_stack();
        add_taint(TAINT_DIE);

        if (in_interrupt())
                panic("Fatal exception in interrupt");

        if (panic_on_oops) {
                printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
                ssleep(5);
                panic("Fatal exception");
        }

        oops_exit();
        do_exit(SIGSEGV);
}

int syscall_ipi(int (*syscall) (struct pt_regs *), struct pt_regs *regs)
{
        return syscall(regs);
}

/* gdb uses break 4,8 */
#define GDB_BREAK_INSN 0x10004
static void handle_gdb_break(struct pt_regs *regs, int wot)
{
        struct siginfo si;

        si.si_signo = SIGTRAP;
        si.si_errno = 0;
        si.si_code = wot;
        si.si_addr = (void __user *) (regs->iaoq[0] & ~3);
        force_sig_info(SIGTRAP, &si, current);
}

static void handle_break(struct pt_regs *regs)
{
        unsigned iir = regs->iir;

        if (unlikely(iir == PARISC_BUG_BREAK_INSN && !user_mode(regs))) {
                /* check if a BUG() or WARN() trapped here.  */
                enum bug_trap_type tt;
                tt = report_bug(regs->iaoq[0] & ~3, regs);
                if (tt == BUG_TRAP_TYPE_WARN) {
                        regs->iaoq[0] += 4;
                        regs->iaoq[1] += 4;
                        return; /* return to next instruction when WARN_ON().  */
                }
                die_if_kernel("Unknown kernel breakpoint", regs,
                        (tt == BUG_TRAP_TYPE_NONE) ? 9 : 0);
        }

#ifdef PRINT_USER_FAULTS
        if (unlikely(iir != GDB_BREAK_INSN)) {
                printk(KERN_DEBUG "break %d,%d: pid=%d command='%s'\n",
                        iir & 31, (iir>>13) & ((1<<13)-1),
                        task_pid_nr(current), current->comm);
                show_regs(regs);
        }
#endif

        /* send standard GDB signal */
        handle_gdb_break(regs, TRAP_BRKPT);
}

static void default_trap(int code, struct pt_regs *regs)
{
        printk(KERN_ERR "Trap %d on CPU %d\n", code, smp_processor_id());
        show_regs(regs);
}

void (*cpu_lpmc) (int code, struct pt_regs *regs) __read_mostly = default_trap;


void transfer_pim_to_trap_frame(struct pt_regs *regs)
{
    register int i;
    extern unsigned int hpmc_pim_data[];
    struct pdc_hpmc_pim_11 *pim_narrow;
    struct pdc_hpmc_pim_20 *pim_wide;

    if (boot_cpu_data.cpu_type >= pcxu) {

        pim_wide = (struct pdc_hpmc_pim_20 *)hpmc_pim_data;

        /*
         * Note: The following code will probably generate a
         * bunch of truncation error warnings from the compiler.
         * Could be handled with an ifdef, but perhaps there
         * is a better way.
         */

        regs->gr[0] = pim_wide->cr[22];

        for (i = 1; i < 32; i++)
            regs->gr[i] = pim_wide->gr[i];

        for (i = 0; i < 32; i++)
            regs->fr[i] = pim_wide->fr[i];

        for (i = 0; i < 8; i++)
            regs->sr[i] = pim_wide->sr[i];

        regs->iasq[0] = pim_wide->cr[17];
        regs->iasq[1] = pim_wide->iasq_back;
        regs->iaoq[0] = pim_wide->cr[18];
        regs->iaoq[1] = pim_wide->iaoq_back;

        regs->sar  = pim_wide->cr[11];
        regs->iir  = pim_wide->cr[19];
        regs->isr  = pim_wide->cr[20];
        regs->ior  = pim_wide->cr[21];
    }
    else {
        pim_narrow = (struct pdc_hpmc_pim_11 *)hpmc_pim_data;

        regs->gr[0] = pim_narrow->cr[22];

        for (i = 1; i < 32; i++)
            regs->gr[i] = pim_narrow->gr[i];

        for (i = 0; i < 32; i++)
            regs->fr[i] = pim_narrow->fr[i];

        for (i = 0; i < 8; i++)
            regs->sr[i] = pim_narrow->sr[i];

        regs->iasq[0] = pim_narrow->cr[17];
        regs->iasq[1] = pim_narrow->iasq_back;
        regs->iaoq[0] = pim_narrow->cr[18];
        regs->iaoq[1] = pim_narrow->iaoq_back;

        regs->sar  = pim_narrow->cr[11];
        regs->iir  = pim_narrow->cr[19];
        regs->isr  = pim_narrow->cr[20];
        regs->ior  = pim_narrow->cr[21];
    }

    /*
     * The following fields only have meaning if we came through
     * another path. So just zero them here.
     */

    regs->ksp = 0;
    regs->kpc = 0;
    regs->orig_r28 = 0;
}


/*
 * This routine is called as a last resort when everything else
 * has gone clearly wrong. We get called for faults in kernel space,
 * and HPMC's.
 */
void parisc_terminate(char *msg, struct pt_regs *regs, int code, unsigned long offset)
{
        static DEFINE_SPINLOCK(terminate_lock);

        oops_in_progress = 1;

        set_eiem(0);
        local_irq_disable();
        spin_lock(&terminate_lock);

        /* unlock the pdc lock if necessary */
        pdc_emergency_unlock();

        /* restart pdc console if necessary */
        if (!console_drivers)
                pdc_console_restart();

        /* Not all paths will gutter the processor... */
        switch(code){

        case 1:
                transfer_pim_to_trap_frame(regs);
                break;

        default:
                /* Fall through */
                break;

        }
            
        {
                /* show_stack(NULL, (unsigned long *)regs->gr[30]); */
                struct unwind_frame_info info;
                unwind_frame_init(&info, current, regs);
                do_show_stack(&info);
        }

        printk("\n");
        printk(KERN_CRIT "%s: Code=%d regs=%p (Addr=" RFMT ")\n",
                        msg, code, regs, offset);
        show_regs(regs);

        spin_unlock(&terminate_lock);

        /* put soft power button back under hardware control;
         * if the user had pressed it once at any time, the 
         * system will shut down immediately right here. */
        pdc_soft_power_button(0);
        
        panic(msg);
}

void notrace handle_interruption(int code, struct pt_regs *regs)
{
        unsigned long fault_address = 0;
        unsigned long fault_space = 0;
        struct siginfo si;

        if (code == 1)
            pdc_console_restart();  /* switch back to pdc if HPMC */
        else
            local_irq_enable();

        /* Security check:
         * If the priority level is still user, and the
         * faulting space is not equal to the active space
         * then the user is attempting something in a space
         * that does not belong to them. Kill the process.
         *
         * This is normally the situation when the user
         * attempts to jump into the kernel space at the
         * wrong offset, be it at the gateway page or a
         * random location.
         *
         * We cannot normally signal the process because it
         * could *be* on the gateway page, and processes
         * executing on the gateway page can't have signals
         * delivered.
         * 
         * We merely readjust the address into the users
         * space, at a destination address of zero, and
         * allow processing to continue.
         */
        if (((unsigned long)regs->iaoq[0] & 3) &&
            ((unsigned long)regs->iasq[0] != (unsigned long)regs->sr[7])) { 
                /* Kill the user process later */
                regs->iaoq[0] = 0 | 3;
                regs->iaoq[1] = regs->iaoq[0] + 4;
                regs->iasq[0] = regs->iasq[1] = regs->sr[7];
                regs->gr[0] &= ~PSW_B;
                return;
        }
        

        switch(code) {

        case  1:
                /* High-priority machine check (HPMC) */
                
                /* set up a new led state on systems shipped with a LED State panel */
                pdc_chassis_send_status(PDC_CHASSIS_DIRECT_HPMC);
                    
                parisc_terminate("High Priority Machine Check (HPMC)",
                                regs, code, 0);
                /* NOT REACHED */
                
        case  2:
                /* Power failure interrupt */
                printk(KERN_CRIT "Power failure interrupt !\n");
                return;

        case  3:
                /* Recovery counter trap */
                regs->gr[0] &= ~PSW_R;
                if (user_space(regs))
                        handle_gdb_break(regs, TRAP_TRACE);
                /* else this must be the start of a syscall - just let it run */
                return;

        case  5:
                /* Low-priority machine check */
                pdc_chassis_send_status(PDC_CHASSIS_DIRECT_LPMC);
                
                flush_cache_all();
                flush_tlb_all();
                cpu_lpmc(5, regs);
                return;

        case  6:
                /* Instruction TLB miss fault/Instruction page fault */
                fault_address = regs->iaoq[0];
                fault_space   = regs->iasq[0];
                break;

        case  8:
                /* Illegal instruction trap */
                die_if_kernel("Illegal instruction", regs, code);
                si.si_code = ILL_ILLOPC;
                goto give_sigill;

        case  9:
                /* Break instruction trap */
                handle_break(regs);
                return;
        
        case 10:
                /* Privileged operation trap */
                die_if_kernel("Privileged operation", regs, code);
                si.si_code = ILL_PRVOPC;
                goto give_sigill;
        
        case 11:
                /* Privileged register trap */
                if ((regs->iir & 0xffdfffe0) == 0x034008a0) {

                        /* This is a MFCTL cr26/cr27 to gr instruction.
                         * PCXS traps on this, so we need to emulate it.
                         */

                        if (regs->iir & 0x00200000)
                                regs->gr[regs->iir & 0x1f] = mfctl(27);
                        else
                                regs->gr[regs->iir & 0x1f] = mfctl(26);

                        regs->iaoq[0] = regs->iaoq[1];
                        regs->iaoq[1] += 4;
                        regs->iasq[0] = regs->iasq[1];
                        return;
                }

                die_if_kernel("Privileged register usage", regs, code);
                si.si_code = ILL_PRVREG;
        give_sigill:
                si.si_signo = SIGILL;
                si.si_errno = 0;
                si.si_addr = (void __user *) regs->iaoq[0];
                force_sig_info(SIGILL, &si, current);
                return;

        case 12:
                /* Overflow Trap, let the userland signal handler do the cleanup */
                si.si_signo = SIGFPE;
                si.si_code = FPE_INTOVF;
                si.si_addr = (void __user *) regs->iaoq[0];
                force_sig_info(SIGFPE, &si, current);
                return;
                
        case 13:
                /* Conditional Trap
                   The condition succeeds in an instruction which traps
                   on condition  */
                if(user_mode(regs)){
                        si.si_signo = SIGFPE;
                        /* Set to zero, and let the userspace app figure it out from
                           the insn pointed to by si_addr */
                        si.si_code = 0;
                        si.si_addr = (void __user *) regs->iaoq[0];
                        force_sig_info(SIGFPE, &si, current);
                        return;
                } 
                /* The kernel doesn't want to handle condition codes */
                break;
                
        case 14:
                /* Assist Exception Trap, i.e. floating point exception. */
                die_if_kernel("Floating point exception", regs, 0); /* quiet */
                handle_fpe(regs);
                return;
                
        case 15:
                /* Data TLB miss fault/Data page fault */
                /* Fall through */
        case 16:
                /* Non-access instruction TLB miss fault */
                /* The instruction TLB entry needed for the target address of the FIC
                   is absent, and hardware can't find it, so we get to cleanup */
                /* Fall through */
        case 17:
                /* Non-access data TLB miss fault/Non-access data page fault */
                fault_address = regs->ior;
                fault_space = regs->isr;
                break;

        case 18:
                /* PCXS only -- later cpu's split this into types 26,27 & 28 */
                /* Check for unaligned access */
                if (check_unaligned(regs)) {
                        handle_unaligned(regs);
                        return;
                }
                /* Fall Through */
        case 26: 
                /* PCXL: Data memory access rights trap */
                fault_address = regs->ior;
                fault_space   = regs->isr;
                break;

        case 19:
                /* Data memory break trap */
                regs->gr[0] |= PSW_X; /* So we can single-step over the trap */
                /* fall thru */
        case 21:
                /* Page reference trap */
                handle_gdb_break(regs, TRAP_HWBKPT);
                return;

        case 25:
                /* Taken branch trap */
                regs->gr[0] &= ~PSW_T;
                if (user_space(regs))
                        handle_gdb_break(regs, TRAP_BRANCH);
                /* else this must be the start of a syscall - just let it
                 * run.
                 */
                return;

        case  7:  
                /* Instruction access rights */
                /* PCXL: Instruction memory protection trap */

                /*
                 * This could be caused by either: 1) a process attempting
                 * to execute within a vma that does not have execute
                 * permission, or 2) an access rights violation caused by a
                 * flush only translation set up by ptep_get_and_clear().
                 * So we check the vma permissions to differentiate the two.
                 * If the vma indicates we have execute permission, then
                 * the cause is the latter one. In this case, we need to
                 * call do_page_fault() to fix the problem.
                 */

                if (user_mode(regs)) {
                        struct vm_area_struct *vma;

                        down_read(&current->mm->mmap_sem);
                        vma = find_vma(current->mm,regs->iaoq[0]);
                        if (vma && (regs->iaoq[0] >= vma->vm_start)
                                && (vma->vm_flags & VM_EXEC)) {

                                fault_address = regs->iaoq[0];
                                fault_space = regs->iasq[0];

                                up_read(&current->mm->mmap_sem);
                                break; /* call do_page_fault() */
                        }
                        up_read(&current->mm->mmap_sem);
                }
                /* Fall Through */
        case 27: 
                /* Data memory protection ID trap */
                if (code == 27 && !user_mode(regs) &&
                        fixup_exception(regs))
                        return;

                die_if_kernel("Protection id trap", regs, code);
                si.si_code = SEGV_MAPERR;
                si.si_signo = SIGSEGV;
                si.si_errno = 0;
                if (code == 7)
                    si.si_addr = (void __user *) regs->iaoq[0];
                else
                    si.si_addr = (void __user *) regs->ior;
                force_sig_info(SIGSEGV, &si, current);
                return;

        case 28: 
                /* Unaligned data reference trap */
                handle_unaligned(regs);
                return;

        default:
                if (user_mode(regs)) {
#ifdef PRINT_USER_FAULTS
                        printk(KERN_DEBUG "\nhandle_interruption() pid=%d command='%s'\n",
                            task_pid_nr(current), current->comm);
                        show_regs(regs);
#endif
                        /* SIGBUS, for lack of a better one. */
                        si.si_signo = SIGBUS;
                        si.si_code = BUS_OBJERR;
                        si.si_errno = 0;
                        si.si_addr = (void __user *) regs->ior;
                        force_sig_info(SIGBUS, &si, current);
                        return;
                }
                pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
                
                parisc_terminate("Unexpected interruption", regs, code, 0);
                /* NOT REACHED */
        }

        if (user_mode(regs)) {
            if ((fault_space >> SPACEID_SHIFT) != (regs->sr[7] >> SPACEID_SHIFT)) {
#ifdef PRINT_USER_FAULTS
                if (fault_space == 0)
                        printk(KERN_DEBUG "User Fault on Kernel Space ");
                else
                        printk(KERN_DEBUG "User Fault (long pointer) (fault %d) ",
                               code);
                printk(KERN_CONT "pid=%d command='%s'\n",
                       task_pid_nr(current), current->comm);
                show_regs(regs);
#endif
                si.si_signo = SIGSEGV;
                si.si_errno = 0;
                si.si_code = SEGV_MAPERR;
                si.si_addr = (void __user *) regs->ior;
                force_sig_info(SIGSEGV, &si, current);
                return;
            }
        }
        else {

            /*
             * The kernel should never fault on its own address space.
             */

            if (fault_space == 0) 
            {
                pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
                parisc_terminate("Kernel Fault", regs, code, fault_address);
        
            }
        }

        do_page_fault(regs, code, fault_address);
}


int __init check_ivt(void *iva)
{
        extern u32 os_hpmc_size;
        extern const u32 os_hpmc[];

        int i;
        u32 check = 0;
        u32 *ivap;
        u32 *hpmcp;
        u32 length;

        if (strcmp((char *)iva, "cows can fly"))
                return -1;

        ivap = (u32 *)iva;

        for (i = 0; i < 8; i++)
            *ivap++ = 0;

        /* Compute Checksum for HPMC handler */
        length = os_hpmc_size;
        ivap[7] = length;

        hpmcp = (u32 *)os_hpmc;

        for (i=0; i<length/4; i++)
            check += *hpmcp++;

        for (i=0; i<8; i++)
            check += ivap[i];

        ivap[5] = -check;

        return 0;
}
        
#ifndef CONFIG_64BIT
extern const void fault_vector_11;
#endif
extern const void fault_vector_20;

void __init trap_init(void)
{
        void *iva;

        if (boot_cpu_data.cpu_type >= pcxu)
                iva = (void *) &fault_vector_20;
        else
#ifdef CONFIG_64BIT
                panic("Can't boot 64-bit OS on PA1.1 processor!");
#else
                iva = (void *) &fault_vector_11;
#endif

        if (check_ivt(iva))
                panic("IVT invalid");
}