Somhow those ll/sc counters in their current form are rather useless as

[linux-2.6/linux-mips.git] / arch / mips / kernel / traps.c

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1994 - 1999, 2000, 01 Ralf Baechle
 * Copyright (C) 1995, 1996 Paul M. Antoine
 * Copyright (C) 1998 Ulf Carlsson
 * Copyright (C) 1999 Silicon Graphics, Inc.
 * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
 * Copyright (C) 2000, 01 MIPS Technologies, Inc.
 * Copyright (C) 2002, 2003  Maciej W. Rozycki
 */
#include <linux/config.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/spinlock.h>

#include <asm/bootinfo.h>
#include <asm/branch.h>
#include <asm/cpu.h>
#include <asm/fpu.h>
#include <asm/inst.h>
#include <asm/module.h>
#include <asm/pgtable.h>
#include <asm/siginfo.h>
#include <asm/system.h>
#include <asm/tlbdebug.h>
#include <asm/traps.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/watch.h>
#include <asm/types.h>

extern asmlinkage void handle_mod(void);
extern asmlinkage void handle_tlbl(void);
extern asmlinkage void handle_tlbs(void);
extern asmlinkage void handle_adel(void);
extern asmlinkage void handle_ades(void);
extern asmlinkage void handle_ibe(void);
extern asmlinkage void handle_dbe(void);
extern asmlinkage void handle_sys(void);
extern asmlinkage void handle_bp(void);
extern asmlinkage void handle_ri(void);
extern asmlinkage void handle_cpu(void);
extern asmlinkage void handle_ov(void);
extern asmlinkage void handle_tr(void);
extern asmlinkage void handle_fpe(void);
extern asmlinkage void handle_mdmx(void);
extern asmlinkage void handle_watch(void);
extern asmlinkage void handle_mcheck(void);
extern asmlinkage void handle_reserved(void);

extern int fpu_emulator_cop1Handler(int xcptno, struct pt_regs *xcp,
        struct mips_fpu_soft_struct *ctx);

void (*board_be_init)(void);
int (*board_be_handler)(struct pt_regs *regs, int is_fixup);

/*
 * These constant is for searching for possible module text segments.
 * MODULE_RANGE is a guess of how much space is likely to be vmalloced.
 */
#define MODULE_RANGE (8*1024*1024)

/*
 * If the address is either in the .text section of the
 * kernel, or in the vmalloc'ed module regions, it *may*
 * be the address of a calling routine
 */

#ifdef CONFIG_MODULES

extern struct module *module_list;
extern struct module kernel_module;

static inline int kernel_text_address(long addr)
{
        extern char _stext, _etext;
        int retval = 0;
        struct module *mod;

        if (addr >= (long) &_stext && addr <= (long) &_etext)
                return 1;

        for (mod = module_list; mod != &kernel_module; mod = mod->next) {
                /* mod_bound tests for addr being inside the vmalloc'ed
                 * module area. Of course it'd be better to test only
                 * for the .text subset... */
                if (mod_bound(addr, 0, mod)) {
                        retval = 1;
                        break;
                }
        }

        return retval;
}

#else

static inline int kernel_text_address(long addr)
{
        extern char _stext, _etext;

        return (addr >= (long) &_stext && addr <= (long) &_etext);
}

#endif

/*
 * This routine abuses get_user()/put_user() to reference pointers
 * with at least a bit of error checking ...
 */
void show_stack(unsigned long *sp)
{
        int i;
        long stackdata;

        sp = sp ? sp : (unsigned long *) &sp;

        printk("Stack:   ");
        i = 1;
        while ((unsigned long) sp & (PAGE_SIZE - 1)) {
                if (i && ((i % 8) == 0))
                        printk("\n");
                if (i > 40) {
                        printk(" ...");
                        break;
                }

                if (__get_user(stackdata, sp++)) {
                        printk(" (Bad stack address)");
                        break;
                }

                printk(" %08lx", stackdata);
                i++;
        }
        printk("\n");
}

void show_trace(unsigned long *sp)
{
        int i;
        long addr;

        sp = sp ? sp : (long *) &sp;

        printk("Call Trace:  ");
        i = 1;
        while ((long) sp & (PAGE_SIZE - 1)) {

                if (__get_user(addr, sp++)) {
                        if (i && ((i % 6) == 0))
                                printk("\n");
                        printk(" (Bad stack address)\n");
                        break;
                }

                /*
                 * If the address is either in the text segment of the
                 * kernel, or in the region which contains vmalloc'ed
                 * memory, it *may* be the address of a calling
                 * routine; if so, print it so that someone tracing
                 * down the cause of the crash will be able to figure
                 * out the call path that was taken.
                 */

                if (kernel_text_address(addr)) {
                        if (i && ((i % 6) == 0))
                                printk("\n");
                        if (i > 40) {
                                printk(" ...");
                                break;
                        }

                        printk(" [<%08lx>]", addr);
                        i++;
                }
        }
        printk("\n");
}

void show_trace_task(struct task_struct *tsk)
{
        show_trace((long *)tsk->thread.reg29);
}

void show_code(unsigned int *pc)
{
        long i;

        printk("\nCode:");

        for(i = -3 ; i < 6 ; i++) {
                unsigned long insn;
                if (__get_user(insn, pc + i)) {
                        printk(" (Bad address in epc)\n");
                        break;
                }
                printk("%c%08lx%c",(i?' ':'<'),insn,(i?' ':'>'));
        }
}

void show_regs(struct pt_regs *regs)
{
        /*
         * Saved main processor registers
         */
        printk("$0 : %08x %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
               0,             regs->regs[1], regs->regs[2], regs->regs[3],
               regs->regs[4], regs->regs[5], regs->regs[6], regs->regs[7]);
        printk("$8 : %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
               regs->regs[8],  regs->regs[9],  regs->regs[10], regs->regs[11],
               regs->regs[12], regs->regs[13], regs->regs[14], regs->regs[15]);
        printk("$16: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
               regs->regs[16], regs->regs[17], regs->regs[18], regs->regs[19],
               regs->regs[20], regs->regs[21], regs->regs[22], regs->regs[23]);
        printk("$24: %08lx %08lx                   %08lx %08lx %08lx %08lx\n",
               regs->regs[24], regs->regs[25],
               regs->regs[28], regs->regs[29], regs->regs[30], regs->regs[31]);
        printk("Hi : %08lx\n", regs->hi);
        printk("Lo : %08lx\n", regs->lo);

        /*
         * Saved cp0 registers
         */
        printk("epc  : %08lx    %s\nStatus: %08lx\nCause : %08lx\n",
               regs->cp0_epc, print_tainted(), regs->cp0_status,
               regs->cp0_cause);
}

void show_registers(struct pt_regs *regs)
{
        show_regs(regs);
        printk("Process %s (pid: %d, stackpage=%08lx)\n",
                current->comm, current->pid, (unsigned long) current);
        show_stack((long *) regs->regs[29]);
        show_trace((long *) regs->regs[29]);
        show_code((unsigned int *) regs->cp0_epc);
        printk("\n");
}

static spinlock_t die_lock = SPIN_LOCK_UNLOCKED;

void __die(const char * str, struct pt_regs * regs, const char * file,
           const char * func, unsigned long line)
{
        console_verbose();
        spin_lock_irq(&die_lock);
        printk("%s", str);
        if (file && func)
                printk(" in %s:%s, line %ld", file, func, line);
        printk(":\n");
        show_registers(regs);
        spin_unlock_irq(&die_lock);
        do_exit(SIGSEGV);
}

void __die_if_kernel(const char * str, struct pt_regs * regs,
                     const char * file, const char * func, unsigned long line)
{
        if (!user_mode(regs))
                __die(str, regs, file, func, line);
}

extern const struct exception_table_entry __start___dbe_table[];
extern const struct exception_table_entry __stop___dbe_table[];

void __declare_dbe_table(void)
{
        __asm__ __volatile__(
        ".section\t__dbe_table,\"a\"\n\t"
        ".previous"
        );
}

static inline unsigned long
search_one_table(const struct exception_table_entry *first,
                 const struct exception_table_entry *last,
                 unsigned long value)
{
        const struct exception_table_entry *mid;
        long diff;

        while (first < last) {
                mid = (last - first) / 2 + first;
                diff = mid->insn - value;
                if (diff < 0)
                        first = mid + 1;
                else
                        last = mid;
        }
        return (first == last && first->insn == value) ? first->nextinsn : 0;
}

extern spinlock_t modlist_lock;

static inline unsigned long
search_dbe_table(unsigned long addr)
{
        unsigned long ret = 0;

#ifndef CONFIG_MODULES
        /* There is only the kernel to search.  */
        ret = search_one_table(__start___dbe_table, __stop___dbe_table-1, addr);
        return ret;
#else
        unsigned long flags;

        /* The kernel is the last "module" -- no need to treat it special.  */
        struct module *mp;
        struct archdata *ap;

        spin_lock_irqsave(&modlist_lock, flags);
        for (mp = module_list; mp != NULL; mp = mp->next) {
                if (!mod_member_present(mp, archdata_end) ||
                    !mod_archdata_member_present(mp, struct archdata,
                                                 dbe_table_end))
                        continue;
                ap = (struct archdata *)(mp->archdata_start);

                if (ap->dbe_table_start == NULL ||
                    !(mp->flags & (MOD_RUNNING | MOD_INITIALIZING)))
                        continue;
                ret = search_one_table(ap->dbe_table_start,
                                       ap->dbe_table_end - 1, addr);
                if (ret)
                        break;
        }
        spin_unlock_irqrestore(&modlist_lock, flags);
        return ret;
#endif
}

asmlinkage void do_be(struct pt_regs *regs)
{
        unsigned long new_epc;
        unsigned long fixup = 0;
        int data = regs->cp0_cause & 4;
        int action = MIPS_BE_FATAL;

        if (data && !user_mode(regs))
                fixup = search_dbe_table(regs->cp0_epc);

        if (fixup)
                action = MIPS_BE_FIXUP;

        if (board_be_handler)
                action = board_be_handler(regs, fixup != 0);

        switch (action) {
        case MIPS_BE_DISCARD:
                return;
        case MIPS_BE_FIXUP:
                if (fixup) {
                        new_epc = fixup_exception(dpf_reg, fixup,
                                                  regs->cp0_epc);
                        regs->cp0_epc = new_epc;
                        return;
                }
                break;
        default:
                break;
        }

        /*
         * Assume it would be too dangerous to continue ...
         */
        printk(KERN_ALERT "%s bus error, epc == %08lx, ra == %08lx\n",
               data ? "Data" : "Instruction",
               regs->cp0_epc, regs->regs[31]);
        die_if_kernel("Oops", regs);
        force_sig(SIGBUS, current);
}

/*
 * ll/sc emulation
 */

#define OPCODE 0xfc000000
#define BASE   0x03e00000
#define RT     0x001f0000
#define OFFSET 0x0000ffff
#define LL     0xc0000000
#define SC     0xe0000000

/*
 * The ll_bit is cleared by r*_switch.S
 */

unsigned long ll_bit;

static struct task_struct *ll_task = NULL;

static inline void simulate_ll(struct pt_regs *regs, unsigned int opcode)
{
        unsigned long value, *vaddr;
        long offset;
        int signal = 0;

        /*
         * analyse the ll instruction that just caused a ri exception
         * and put the referenced address to addr.
         */

        /* sign extend offset */
        offset = opcode & OFFSET;
        offset <<= 16;
        offset >>= 16;

        vaddr = (unsigned long *)((long)(regs->regs[(opcode & BASE) >> 21]) + offset);

        if ((unsigned long)vaddr & 3) {
                signal = SIGBUS;
                goto sig;
        }
        if (get_user(value, vaddr)) {
                signal = SIGSEGV;
                goto sig;
        }

        if (ll_task == NULL || ll_task == current) {
                ll_bit = 1;
        } else {
                ll_bit = 0;
        }
        ll_task = current;

        regs->regs[(opcode & RT) >> 16] = value;

        compute_return_epc(regs);
        return;

sig:
        force_sig(signal, current);
}

static inline void simulate_sc(struct pt_regs *regs, unsigned int opcode)
{
        unsigned long *vaddr, reg;
        long offset;
        int signal = 0;

        /*
         * analyse the sc instruction that just caused a ri exception
         * and put the referenced address to addr.
         */

        /* sign extend offset */
        offset = opcode & OFFSET;
        offset <<= 16;
        offset >>= 16;

        vaddr = (unsigned long *)((long)(regs->regs[(opcode & BASE) >> 21]) + offset);
        reg = (opcode & RT) >> 16;

        if ((unsigned long)vaddr & 3) {
                signal = SIGBUS;
                goto sig;
        }
        if (ll_bit == 0 || ll_task != current) {
                regs->regs[reg] = 0;
                compute_return_epc(regs);
                return;
        }

        if (put_user(regs->regs[reg], vaddr)) {
                signal = SIGSEGV;
                goto sig;
        }

        regs->regs[reg] = 1;

        compute_return_epc(regs);
        return;

sig:
        force_sig(signal, current);
}

/*
 * ll uses the opcode of lwc0 and sc uses the opcode of swc0.  That is both
 * opcodes are supposed to result in coprocessor unusable exceptions if
 * executed on ll/sc-less processors.  That's the theory.  In practice a
 * few processors such as NEC's VR4100 throw reserved instruction exceptions
 * instead, so we're doing the emulation thing in both exception handlers.
 */
static inline int simulate_llsc(struct pt_regs *regs)
{
        unsigned int opcode;

        if (unlikely(get_insn_opcode(regs, &opcode)))
                return -EFAULT;

        if ((opcode & OPCODE) == LL) {
                simulate_ll(regs, opcode);
                return 0;
        }
        if ((opcode & OPCODE) == SC) {
                simulate_sc(regs, opcode);
                return 0;
        }
}

asmlinkage void do_ov(struct pt_regs *regs)
{
        siginfo_t info;

        info.si_code = FPE_INTOVF;
        info.si_signo = SIGFPE;
        info.si_errno = 0;
        info.si_addr = (void *)regs->cp0_epc;
        force_sig_info(SIGFPE, &info, current);
}

/*
 * XXX Delayed fp exceptions when doing a lazy ctx switch XXX
 */
asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
{
        if (fcr31 & FPU_CSR_UNI_X) {
                int sig;

                /*
                 * Unimplemented operation exception.  If we've got the full
                 * software emulator on-board, let's use it...
                 *
                 * Force FPU to dump state into task/thread context.  We're
                 * moving a lot of data here for what is probably a single
                 * instruction, but the alternative is to pre-decode the FP
                 * register operands before invoking the emulator, which seems
                 * a bit extreme for what should be an infrequent event.
                 */
                save_fp(current);

                /* Run the emulator */
                sig = fpu_emulator_cop1Handler (0, regs,
                        &current->thread.fpu.soft);

                /*
                 * We can't allow the emulated instruction to leave any of
                 * the cause bit set in $fcr31.
                 */
                current->thread.fpu.soft.sr &= ~FPU_CSR_ALL_X;

                /* Restore the hardware register state */
                restore_fp(current);

                /* If something went wrong, signal */
                if (sig)
                        force_sig(sig, current);

                return;
        }

        force_sig(SIGFPE, current);
}

static inline int get_insn_opcode(struct pt_regs *regs, unsigned int *opcode)
{
        unsigned int *epc;

        epc = (unsigned int *) regs->cp0_epc +
              ((regs->cp0_cause & CAUSEF_BD) != 0);
        if (!get_user(*opcode, epc))
                return 0;

        force_sig(SIGSEGV, current);
        return 1;
}

asmlinkage void do_bp(struct pt_regs *regs)
{
        unsigned int opcode, bcode;
        siginfo_t info;

        if (get_insn_opcode(regs, &opcode))
                return;

        /*
         * There is the ancient bug in the MIPS assemblers that the break
         * code starts left to bit 16 instead to bit 6 in the opcode.
         * Gas is bug-compatible ...
         */
        bcode = ((opcode >> 16) & ((1 << 20) - 1));

        /*
         * (A short test says that IRIX 5.3 sends SIGTRAP for all break
         * insns, even for break codes that indicate arithmetic failures.
         * Weird ...)
         * But should we continue the brokenness???  --macro
         */
        switch (bcode) {
        case 6:
        case 7:
                if (bcode == 7)
                        info.si_code = FPE_INTDIV;
                else
                        info.si_code = FPE_INTOVF;
                info.si_signo = SIGFPE;
                info.si_errno = 0;
                info.si_addr = (void *)regs->cp0_epc;
                force_sig_info(SIGFPE, &info, current);
                break;
        default:
                force_sig(SIGTRAP, current);
        }
}

asmlinkage void do_tr(struct pt_regs *regs)
{
        unsigned int opcode, tcode = 0;
        siginfo_t info;

        if (get_insn_opcode(regs, &opcode))
                return;

        /* Immediate versions don't provide a code.  */
        if (!(opcode & OPCODE))
                tcode = ((opcode >> 6) & ((1 << 20) - 1));

        /*
         * (A short test says that IRIX 5.3 sends SIGTRAP for all trap
         * insns, even for trap codes that indicate arithmetic failures.
         * Weird ...)
         * But should we continue the brokenness???  --macro
         */
        switch (tcode) {
        case 6:
        case 7:
                if (tcode == 7)
                        info.si_code = FPE_INTDIV;
                else
                        info.si_code = FPE_INTOVF;
                info.si_signo = SIGFPE;
                info.si_errno = 0;
                info.si_addr = (void *)regs->cp0_epc;
                force_sig_info(SIGFPE, &info, current);
                break;
        default:
                force_sig(SIGTRAP, current);
        }
}

asmlinkage void do_ri(struct pt_regs *regs)
{
        die_if_kernel("Reserved instruction in kernel code", regs);

        if (!cpu_has_llsc)
                if (!simulate_llsc(regs))
                        return;

        force_sig(SIGILL, current);
}

asmlinkage void do_cpu(struct pt_regs *regs)
{
        unsigned int cpid;

        die_if_kernel("do_cpu invoked from kernel context!", regs);

        cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;

        switch (cpid) {
        case 0:
                if (cpu_has_llsc)
                        break;

                if (!simulate_llsc(regs))
                        return;
                break;

        case 1:
                own_fpu();
                if (current->used_math) {       /* Using the FPU again.  */
                        restore_fp(current);
                } else {                        /* First time FPU user.  */
                        init_fpu();
                        current->used_math = 1;
                }

                if (!cpu_has_fpu) {
                        int sig = fpu_emulator_cop1Handler(0, regs,
                                                &current->thread.fpu.soft);
                        if (sig)
                                force_sig(sig, current);
                }

                return;

        case 2:
        case 3:
                break;
        }

        force_sig(SIGILL, current);
}

asmlinkage void do_mdmx(struct pt_regs *regs)
{
        force_sig(SIGILL, current);
}

asmlinkage void do_watch(struct pt_regs *regs)
{
        /*
         * We use the watch exception where available to detect stack
         * overflows.
         */
        dump_tlb_all();
        show_regs(regs);
        panic("Caught WATCH exception - probably caused by stack overflow.");
}

asmlinkage void do_mcheck(struct pt_regs *regs)
{
        show_regs(regs);
        dump_tlb_all();
        /*
         * Some chips may have other causes of machine check (e.g. SB1
         * graduation timer)
         */
        panic("Caught Machine Check exception - %scaused by multiple "
              "matching entries in the TLB.",
              (regs->cp0_status & ST0_TS) ? "" : "not ");
}

asmlinkage void do_reserved(struct pt_regs *regs)
{
        /*
         * Game over - no way to handle this if it ever occurs.  Most probably
         * caused by a new unknown cpu type or after another deadly
         * hard/software error.
         */
        show_regs(regs);
        panic("Caught reserved exception %ld - should not happen.",
              (regs->cp0_cause & 0x7f) >> 2);
}

/*
 * Some MIPS CPUs can enable/disable for cache parity detection, but do
 * it different ways.
 */
static inline void parity_protection_init(void)
{
        switch (current_cpu_data.cputype) {
        case CPU_5KC:
                /* Set the PE bit (bit 31) in the c0_ecc register. */
                printk(KERN_INFO "Enable the cache parity protection for "
                       "MIPS 5KC CPUs.\n");
                write_c0_ecc(read_c0_ecc() | 0x80000000);
                break;
        default:
                break;
        }
}

asmlinkage void cache_parity_error(void)
{
        unsigned int reg_val;

        /* For the moment, report the problem and hang. */
        printk("Cache error exception:\n");
        printk("cp0_errorepc == %08lx\n", read_c0_errorepc());
        reg_val = read_c0_cacheerr();
        printk("c0_cacheerr == %08x\n", reg_val);

        printk("Decoded c0_cacheerr: %s cache fault in %s reference.\n",
               reg_val & (1<<30) ? "secondary" : "primary",
               reg_val & (1<<31) ? "data" : "insn");
        printk("Error bits: %s%s%s%s%s%s%s\n",
               reg_val & (1<<29) ? "ED " : "",
               reg_val & (1<<28) ? "ET " : "",
               reg_val & (1<<26) ? "EE " : "",
               reg_val & (1<<25) ? "EB " : "",
               reg_val & (1<<24) ? "EI " : "",
               reg_val & (1<<23) ? "E1 " : "",
               reg_val & (1<<22) ? "E0 " : "");
        printk("IDX: 0x%08x\n", reg_val & ((1<<22)-1));

#if defined(CONFIG_CPU_MIPS32) || defined (CONFIG_CPU_MIPS64)
        if (reg_val & (1<<22))
                printk("DErrAddr0: 0x%08x\n", read_c0_derraddr0());

        if (reg_val & (1<<23))
                printk("DErrAddr1: 0x%08x\n", read_c0_derraddr1());
#endif

        panic("Can't handle the cache error!");
}

/*
 * SDBBP EJTAG debug exception handler.
 * We skip the instruction and return to the next instruction.
 */
void ejtag_exception_handler(struct pt_regs *regs)
{
        unsigned long depc, old_epc;
        unsigned int debug;

        printk("SDBBP EJTAG debug exception - not handled yet, just ignored!\n");
        depc = read_c0_depc();
        debug = read_c0_debug();
        printk("c0_depc = %08lx, DEBUG = %08x\n", depc, debug);
        if (debug & 0x80000000) {
                /*
                 * In branch delay slot.
                 * We cheat a little bit here and use EPC to calculate the
                 * debug return address (DEPC). EPC is restored after the
                 * calculation.
                 */
                old_epc = regs->cp0_epc;
                regs->cp0_epc = depc;
                __compute_return_epc(regs);
                depc = regs->cp0_epc;
                regs->cp0_epc = old_epc;
        } else
                depc += 4;
        write_c0_depc(depc);

#if 0
        printk("\n\n----- Enable EJTAG single stepping ----\n\n");
        write_c0_debug(debug | 0x100);
#endif
}

/*
 * NMI exception handler.
 */
void nmi_exception_handler(struct pt_regs *regs)
{
        printk("NMI taken!!!!\n");
        die("NMI", regs);
        while(1) ;
}

unsigned long exception_handlers[32];

/*
 * As a side effect of the way this is implemented we're limited
 * to interrupt handlers in the address range from
 * KSEG0 <= x < KSEG0 + 256mb on the Nevada.  Oh well ...
 */
void *set_except_vector(int n, void *addr)
{
        unsigned long handler = (unsigned long) addr;
        unsigned long old_handler = exception_handlers[n];

        exception_handlers[n] = handler;
        if (n == 0 && cpu_has_divec) {
                *(volatile u32 *)(KSEG0+0x200) = 0x08000000 |
                                                 (0x03ffffff & (handler >> 2));
                flush_icache_range(KSEG0+0x200, KSEG0 + 0x204);
        }
        return (void *)old_handler;
}

asmlinkage int (*save_fp_context)(struct sigcontext *sc);
asmlinkage int (*restore_fp_context)(struct sigcontext *sc);

extern asmlinkage int _save_fp_context(struct sigcontext *sc);
extern asmlinkage int _restore_fp_context(struct sigcontext *sc);

extern asmlinkage int fpu_emulator_save_context(struct sigcontext *sc);
extern asmlinkage int fpu_emulator_restore_context(struct sigcontext *sc);

void __init per_cpu_trap_init(void)
{
        unsigned int cpu = smp_processor_id();

        /* Some firmware leaves the BEV flag set, clear it.  */
        clear_c0_status(ST0_CU1|ST0_CU2|ST0_CU3|ST0_BEV);

        /*
         * Some MIPS CPUs have a dedicated interrupt vector which reduces the
         * interrupt processing overhead.  Use it where available.
         */
        if (cpu_has_divec)
                set_c0_cause(CAUSEF_IV);

        cpu_data[cpu].asid_cache = ASID_FIRST_VERSION;
        write_c0_context(cpu << 23);
}

void __init trap_init(void)
{
        extern char except_vec1_generic;
        extern char except_vec3_generic, except_vec3_r4000;
        extern char except_vec_ejtag_debug;
        extern char except_vec4;
        unsigned long i;

        per_cpu_trap_init();

        /* Copy the generic exception handler code to it's final destination. */
        memcpy((void *)(KSEG0 + 0x80), &except_vec1_generic, 0x80);

        /*
         * Setup default vectors
         */
        for (i = 0; i <= 31; i++)
                set_except_vector(i, handle_reserved);

        /*
         * Copy the EJTAG debug exception vector handler code to it's final
         * destination.
         */
        if (cpu_has_ejtag)
                memcpy((void *)(KSEG0 + 0x300), &except_vec_ejtag_debug, 0x80);

        /*
         * Only some CPUs have the watch exceptions or a dedicated
         * interrupt vector.
         */
        if (cpu_has_watch)
                set_except_vector(23, handle_watch);

        /*
         * Some MIPS CPUs have a dedicated interrupt vector which reduces the
         * interrupt processing overhead.  Use it where available.
         */
        if (cpu_has_divec)
                memcpy((void *)(KSEG0 + 0x200), &except_vec4, 8);

        /*
         * Some CPUs can enable/disable for cache parity detection, but does
         * it different ways.
         */
        parity_protection_init();

        /*
         * The Data Bus Errors / Instruction Bus Errors are signaled
         * by external hardware.  Therefore these two exceptions
         * may have board specific handlers.
         */
        if (board_be_init)
                board_be_init();

        set_except_vector(1, handle_mod);
        set_except_vector(2, handle_tlbl);
        set_except_vector(3, handle_tlbs);
        set_except_vector(4, handle_adel);
        set_except_vector(5, handle_ades);

        set_except_vector(6, handle_ibe);
        set_except_vector(7, handle_dbe);

        set_except_vector(8, handle_sys);
        set_except_vector(9, handle_bp);
        set_except_vector(10, handle_ri);
        set_except_vector(11, handle_cpu);
        set_except_vector(12, handle_ov);
        set_except_vector(13, handle_tr);
        set_except_vector(22, handle_mdmx);

        if (cpu_has_fpu && !cpu_has_nofpuex)
                set_except_vector(15, handle_fpe);

        if (cpu_has_mcheck)
                set_except_vector(24, handle_mcheck);

        if (cpu_has_vce)
                memcpy((void *)(KSEG0 + 0x180), &except_vec3_r4000, 0x80);
        else if (cpu_has_4kex)
                memcpy((void *)(KSEG0 + 0x180), &except_vec3_generic, 0x80);
        else
                memcpy((void *)(KSEG0 + 0x080), &except_vec3_generic, 0x80);

        if (current_cpu_data.cputype == CPU_R6000 ||
            current_cpu_data.cputype == CPU_R6000A) {
                /*
                 * The R6000 is the only R-series CPU that features a machine
                 * check exception (similar to the R4000 cache error) and
                 * unaligned ldc1/sdc1 exception.  The handlers have not been
                 * written yet.  Well, anyway there is no R6000 machine on the
                 * current list of targets for Linux/MIPS.
                 * (Duh, crap, there is someone with a tripple R6k machine)
                 */
                //set_except_vector(14, handle_mc);
                //set_except_vector(15, handle_ndc);
        }

        if (cpu_has_fpu) {
                save_fp_context = _save_fp_context;
                restore_fp_context = _restore_fp_context;
        } else {
                save_fp_context = fpu_emulator_save_context;
                restore_fp_context = fpu_emulator_restore_context;
        }

        flush_icache_range(KSEG0, KSEG0 + 0x400);

        if (current_cpu_data.isa_level == MIPS_CPU_ISA_IV)
                set_c0_status(ST0_XX);

        atomic_inc(&init_mm.mm_count);  /* XXX UP?  */
        current->active_mm = &init_mm;

        /* XXX Must be done for all CPUs  */
        TLBMISS_HANDLER_SETUP();
}