traps.c

		if (notify_die(DIE_UPROBE_XOL, "uprobe_xol", regs, bcode,
			       current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
			goto out;
		else
			break;
	case BRK_KPROBE_BP:
		if (notify_die(DIE_BREAK, "debug", regs, bcode,
			       current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
			goto out;
		else
			break;
	case BRK_KPROBE_SSTEPBP:
		if (notify_die(DIE_SSTEPBP, "single_step", regs, bcode,
			       current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
			goto out;
		else
			break;
	default:
		break;
	}

	do_trap_or_bp(regs, bcode, TRAP_BRKPT, "Break");

out:
	set_fs(seg);
	exception_exit(prev_state);
	return;

out_sigsegv:
	force_sig(SIGSEGV, current);
	goto out;
}

asmlinkage void do_tr(struct pt_regs *regs)
{
	u32 opcode, tcode = 0;
	enum ctx_state prev_state;
	u16 instr[2];
	mm_segment_t seg;
	unsigned long epc = msk_isa16_mode(exception_epc(regs));

	seg = get_fs();
	if (!user_mode(regs))
		set_fs(get_ds());

	prev_state = exception_enter();
	current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
	if (get_isa16_mode(regs->cp0_epc)) {
		if (__get_user(instr[0], (u16 __user *)(epc + 0)) ||
		    __get_user(instr[1], (u16 __user *)(epc + 2)))
			goto out_sigsegv;
		opcode = (instr[0] << 16) | instr[1];
		/* Immediate versions don't provide a code.  */
		if (!(opcode & OPCODE))
			tcode = (opcode >> 12) & ((1 << 4) - 1);
	} else {
		if (__get_user(opcode, (u32 __user *)epc))
			goto out_sigsegv;
		/* Immediate versions don't provide a code.  */
		if (!(opcode & OPCODE))
			tcode = (opcode >> 6) & ((1 << 10) - 1);
	}

	do_trap_or_bp(regs, tcode, 0, "Trap");

out:
	set_fs(seg);
	exception_exit(prev_state);
	return;

out_sigsegv:
	force_sig(SIGSEGV, current);
	goto out;
}

asmlinkage void do_ri(struct pt_regs *regs)
{
	unsigned int __user *epc = (unsigned int __user *)exception_epc(regs);
	unsigned long old_epc = regs->cp0_epc;
	unsigned long old31 = regs->regs[31];
	enum ctx_state prev_state;
	unsigned int opcode = 0;
	int status = -1;

	/*
	 * Avoid any kernel code. Just emulate the R2 instruction
	 * as quickly as possible.
	 */
	if (mipsr2_emulation && cpu_has_mips_r6 &&
	    likely(user_mode(regs)) &&
	    likely(get_user(opcode, epc) >= 0)) {
		unsigned long fcr31 = 0;

		status = mipsr2_decoder(regs, opcode, &fcr31);
		switch (status) {
		case 0:
		case SIGEMT:
			task_thread_info(current)->r2_emul_return = 1;
			return;
		case SIGILL:
			goto no_r2_instr;
		default:
			process_fpemu_return(status,
					     &current->thread.cp0_baduaddr,
					     fcr31);
			task_thread_info(current)->r2_emul_return = 1;
			return;
		}
	}

no_r2_instr:

	prev_state = exception_enter();
	current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;

	if (notify_die(DIE_RI, "RI Fault", regs, 0, current->thread.trap_nr,
		       SIGILL) == NOTIFY_STOP)
		goto out;

	die_if_kernel("Reserved instruction in kernel code", regs);

	if (unlikely(compute_return_epc(regs) < 0))
		goto out;

	if (get_isa16_mode(regs->cp0_epc)) {
		unsigned short mmop[2] = { 0 };

		if (unlikely(get_user(mmop[0], (u16 __user *)epc + 0) < 0))
			status = SIGSEGV;
		if (unlikely(get_user(mmop[1], (u16 __user *)epc + 1) < 0))
			status = SIGSEGV;
		opcode = mmop[0];
		opcode = (opcode << 16) | mmop[1];

		if (status < 0)
			status = simulate_rdhwr_mm(regs, opcode);
	} else {
		if (unlikely(get_user(opcode, epc) < 0))
			status = SIGSEGV;

		if (!cpu_has_llsc && status < 0)
			status = simulate_llsc(regs, opcode);

		if (status < 0)
			status = simulate_rdhwr_normal(regs, opcode);

		if (status < 0)
			status = simulate_sync(regs, opcode);

		if (status < 0)
			status = simulate_fp(regs, opcode, old_epc, old31);
	}

	if (status < 0)
		status = SIGILL;

	if (unlikely(status > 0)) {
		regs->cp0_epc = old_epc;		/* Undo skip-over.  */
		regs->regs[31] = old31;
		force_sig(status, current);
	}

out:
	exception_exit(prev_state);
}

/*
 * MIPS MT processors may have fewer FPU contexts than CPU threads. If we've
 * emulated more than some threshold number of instructions, force migration to
 * a "CPU" that has FP support.
 */
static void mt_ase_fp_affinity(void)
{
#ifdef CONFIG_MIPS_MT_FPAFF
	if (mt_fpemul_threshold > 0 &&
	     ((current->thread.emulated_fp++ > mt_fpemul_threshold))) {
		/*
		 * If there's no FPU present, or if the application has already
		 * restricted the allowed set to exclude any CPUs with FPUs,
		 * we'll skip the procedure.
		 */
		if (cpumask_intersects(&current->cpus_allowed, &mt_fpu_cpumask)) {
			cpumask_t tmask;

			current->thread.user_cpus_allowed
				= current->cpus_allowed;
			cpumask_and(&tmask, &current->cpus_allowed,
				    &mt_fpu_cpumask);
			set_cpus_allowed_ptr(current, &tmask);
			set_thread_flag(TIF_FPUBOUND);
		}
	}
#endif /* CONFIG_MIPS_MT_FPAFF */
}

/*
 * No lock; only written during early bootup by CPU 0.
 */
static RAW_NOTIFIER_HEAD(cu2_chain);

int __ref register_cu2_notifier(struct notifier_block *nb)
{
	return raw_notifier_chain_register(&cu2_chain, nb);
}

int cu2_notifier_call_chain(unsigned long val, void *v)
{
	return raw_notifier_call_chain(&cu2_chain, val, v);
}

static int default_cu2_call(struct notifier_block *nfb, unsigned long action,
	void *data)
{
	struct pt_regs *regs = data;

	die_if_kernel("COP2: Unhandled kernel unaligned access or invalid "
			      "instruction", regs);
	force_sig(SIGILL, current);

	return NOTIFY_OK;
}

static int wait_on_fp_mode_switch(atomic_t *p)
{
	/*
	 * The FP mode for this task is currently being switched. That may
	 * involve modifications to the format of this tasks FP context which
	 * make it unsafe to proceed with execution for the moment. Instead,
	 * schedule some other task.
	 */
	schedule();
	return 0;
}

static int enable_restore_fp_context(int msa)
{
	int err, was_fpu_owner, prior_msa;

	/*
	 * If an FP mode switch is currently underway, wait for it to
	 * complete before proceeding.
	 */
	wait_on_atomic_t(&current->mm->context.fp_mode_switching,
			 wait_on_fp_mode_switch, TASK_KILLABLE);

	if (!used_math()) {
		/* First time FP context user. */
		preempt_disable();
		err = init_fpu();
		if (msa && !err) {
			enable_msa();
			_init_msa_upper();
			set_thread_flag(TIF_USEDMSA);
			set_thread_flag(TIF_MSA_CTX_LIVE);
		}
		preempt_enable();
		if (!err)
			set_used_math();
		return err;
	}

	/*
	 * This task has formerly used the FP context.
	 *
	 * If this thread has no live MSA vector context then we can simply
	 * restore the scalar FP context. If it has live MSA vector context
	 * (that is, it has or may have used MSA since last performing a
	 * function call) then we'll need to restore the vector context. This
	 * applies even if we're currently only executing a scalar FP
	 * instruction. This is because if we were to later execute an MSA
	 * instruction then we'd either have to:
	 *
	 *  - Restore the vector context & clobber any registers modified by
	 *    scalar FP instructions between now & then.
	 *
	 * or
	 *
	 *  - Not restore the vector context & lose the most significant bits
	 *    of all vector registers.
	 *
	 * Neither of those options is acceptable. We cannot restore the least
	 * significant bits of the registers now & only restore the most
	 * significant bits later because the most significant bits of any
	 * vector registers whose aliased FP register is modified now will have
	 * been zeroed. We'd have no way to know that when restoring the vector
	 * context & thus may load an outdated value for the most significant
	 * bits of a vector register.
	 */
	if (!msa && !thread_msa_context_live())
		return own_fpu(1);

	/*
	 * This task is using or has previously used MSA. Thus we require
	 * that Status.FR == 1.
	 */
	preempt_disable();
	was_fpu_owner = is_fpu_owner();
	err = own_fpu_inatomic(0);
	if (err)
		goto out;

	enable_msa();
	write_msa_csr(current->thread.fpu.msacsr);
	set_thread_flag(TIF_USEDMSA);

	/*
	 * If this is the first time that the task is using MSA and it has
	 * previously used scalar FP in this time slice then we already nave
	 * FP context which we shouldn't clobber. We do however need to clear
	 * the upper 64b of each vector register so that this task has no
	 * opportunity to see data left behind by another.
	 */
	prior_msa = test_and_set_thread_flag(TIF_MSA_CTX_LIVE);
	if (!prior_msa && was_fpu_owner) {
		_init_msa_upper();

		goto out;
	}

	if (!prior_msa) {
		/*
		 * Restore the least significant 64b of each vector register
		 * from the existing scalar FP context.
		 */
		_restore_fp(current);

		/*
		 * The task has not formerly used MSA, so clear the upper 64b
		 * of each vector register such that it cannot see data left
		 * behind by another task.
		 */
		_init_msa_upper();
	} else {
		/* We need to restore the vector context. */
		restore_msa(current);

		/* Restore the scalar FP control & status register */
		if (!was_fpu_owner)
			write_32bit_cp1_register(CP1_STATUS,
						 current->thread.fpu.fcr31);
	}

out:
	preempt_enable();

	return 0;
}

asmlinkage void do_cpu(struct pt_regs *regs)
{
	enum ctx_state prev_state;
	unsigned int __user *epc;
	unsigned long old_epc, old31;
	void __user *fault_addr;
	unsigned int opcode;
	unsigned long fcr31;
	unsigned int cpid;
	int status, err;
	unsigned long __maybe_unused flags;
	int sig;

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

	if (cpid != 2)
		die_if_kernel("do_cpu invoked from kernel context!", regs);

	switch (cpid) {
	case 0:
		epc = (unsigned int __user *)exception_epc(regs);
		old_epc = regs->cp0_epc;
		old31 = regs->regs[31];
		opcode = 0;
		status = -1;

		if (unlikely(compute_return_epc(regs) < 0))
			break;

		if (!get_isa16_mode(regs->cp0_epc)) {
			if (unlikely(get_user(opcode, epc) < 0))
				status = SIGSEGV;

			if (!cpu_has_llsc && status < 0)
				status = simulate_llsc(regs, opcode);
		}

		if (status < 0)
			status = SIGILL;

		if (unlikely(status > 0)) {
			regs->cp0_epc = old_epc;	/* Undo skip-over.  */
			regs->regs[31] = old31;
			force_sig(status, current);
		}

		break;

	case 3:
		/*
		 * The COP3 opcode space and consequently the CP0.Status.CU3
		 * bit and the CP0.Cause.CE=3 encoding have been removed as
		 * of the MIPS III ISA.  From the MIPS IV and MIPS32r2 ISAs
		 * up the space has been reused for COP1X instructions, that
		 * are enabled by the CP0.Status.CU1 bit and consequently
		 * use the CP0.Cause.CE=1 encoding for Coprocessor Unusable
		 * exceptions.  Some FPU-less processors that implement one
		 * of these ISAs however use this code erroneously for COP1X
		 * instructions.  Therefore we redirect this trap to the FP
		 * emulator too.
		 */
		if (raw_cpu_has_fpu || !cpu_has_mips_4_5_64_r2_r6) {
			force_sig(SIGILL, current);
			break;
		}
		/* Fall through.  */

	case 1:
		err = enable_restore_fp_context(0);

		if (raw_cpu_has_fpu && !err)
			break;

		sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 0,
					       &fault_addr);
		fcr31 = current->thread.fpu.fcr31;

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

		/* Send a signal if required.  */
		if (!process_fpemu_return(sig, fault_addr, fcr31) && !err)
			mt_ase_fp_affinity();

		break;

	case 2:
		raw_notifier_call_chain(&cu2_chain, CU2_EXCEPTION, regs);
		break;
	}

	exception_exit(prev_state);
}

asmlinkage void do_msa_fpe(struct pt_regs *regs, unsigned int msacsr)
{
	enum ctx_state prev_state;

	prev_state = exception_enter();
	current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
	if (notify_die(DIE_MSAFP, "MSA FP exception", regs, 0,
		       current->thread.trap_nr, SIGFPE) == NOTIFY_STOP)
		goto out;

	/* Clear MSACSR.Cause before enabling interrupts */
	write_msa_csr(msacsr & ~MSA_CSR_CAUSEF);
	local_irq_enable();

	die_if_kernel("do_msa_fpe invoked from kernel context!", regs);
	force_sig(SIGFPE, current);
out:
	exception_exit(prev_state);
}

asmlinkage void do_msa(struct pt_regs *regs)
{
	enum ctx_state prev_state;
	int err;

	prev_state = exception_enter();

	if (!cpu_has_msa || test_thread_flag(TIF_32BIT_FPREGS)) {
		force_sig(SIGILL, current);
		goto out;
	}

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

	err = enable_restore_fp_context(1);
	if (err)
		force_sig(SIGILL, current);
out:
	exception_exit(prev_state);
}

asmlinkage void do_mdmx(struct pt_regs *regs)
{
	enum ctx_state prev_state;

	prev_state = exception_enter();
	force_sig(SIGILL, current);
	exception_exit(prev_state);
}

/*
 * Called with interrupts disabled.
 */
asmlinkage void do_watch(struct pt_regs *regs)
{
	siginfo_t info = { .si_signo = SIGTRAP, .si_code = TRAP_HWBKPT };
	enum ctx_state prev_state;
	u32 cause;

	prev_state = exception_enter();
	/*
	 * Clear WP (bit 22) bit of cause register so we don't loop
	 * forever.
	 */
	cause = read_c0_cause();
	cause &= ~(1 << 22);
	write_c0_cause(cause);

	/*
	 * If the current thread has the watch registers loaded, save
	 * their values and send SIGTRAP.  Otherwise another thread
	 * left the registers set, clear them and continue.
	 */
	if (test_tsk_thread_flag(current, TIF_LOAD_WATCH)) {
		mips_read_watch_registers();
		local_irq_enable();
		force_sig_info(SIGTRAP, &info, current);
	} else {
		mips_clear_watch_registers();
		local_irq_enable();
	}
	exception_exit(prev_state);
}

asmlinkage void do_mcheck(struct pt_regs *regs)
{
	int multi_match = regs->cp0_status & ST0_TS;
	enum ctx_state prev_state;
	mm_segment_t old_fs = get_fs();

	prev_state = exception_enter();
	show_regs(regs);

	if (multi_match) {
		dump_tlb_regs();
		pr_info("\n");
		dump_tlb_all();
	}

	if (!user_mode(regs))
		set_fs(KERNEL_DS);

	show_code((unsigned int __user *) regs->cp0_epc);

	set_fs(old_fs);

	/*
	 * 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.",
	      (multi_match) ? "" : "not ");
}

asmlinkage void do_mt(struct pt_regs *regs)
{
	int subcode;

	subcode = (read_vpe_c0_vpecontrol() & VPECONTROL_EXCPT)
			>> VPECONTROL_EXCPT_SHIFT;
	switch (subcode) {
	case 0:
		printk(KERN_DEBUG "Thread Underflow\n");
		break;
	case 1:
		printk(KERN_DEBUG "Thread Overflow\n");
		break;
	case 2:
		printk(KERN_DEBUG "Invalid YIELD Qualifier\n");
		break;
	case 3:
		printk(KERN_DEBUG "Gating Storage Exception\n");
		break;
	case 4:
		printk(KERN_DEBUG "YIELD Scheduler Exception\n");
		break;
	case 5:
		printk(KERN_DEBUG "Gating Storage Scheduler Exception\n");
		break;
	default:
		printk(KERN_DEBUG "*** UNKNOWN THREAD EXCEPTION %d ***\n",
			subcode);
		break;
	}
	die_if_kernel("MIPS MT Thread exception in kernel", regs);

	force_sig(SIGILL, current);
}


asmlinkage void do_dsp(struct pt_regs *regs)
{
	if (cpu_has_dsp)
		panic("Unexpected DSP exception");

	force_sig(SIGILL, current);
}

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);
}

static int __initdata l1parity = 1;
static int __init nol1parity(char *s)
{
	l1parity = 0;
	return 1;
}
__setup("nol1par", nol1parity);
static int __initdata l2parity = 1;
static int __init nol2parity(char *s)
{
	l2parity = 0;
	return 1;
}
__setup("nol2par", nol2parity);

/*
 * 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_type()) {
	case CPU_24K:
	case CPU_34K:
	case CPU_74K:
	case CPU_1004K:
	case CPU_1074K:
	case CPU_INTERAPTIV:
	case CPU_PROAPTIV:
	case CPU_P5600:
	case CPU_QEMU_GENERIC:
	case CPU_I6400:
		{
#define ERRCTL_PE	0x80000000
#define ERRCTL_L2P	0x00800000
			unsigned long errctl;
			unsigned int l1parity_present, l2parity_present;

			errctl = read_c0_ecc();
			errctl &= ~(ERRCTL_PE|ERRCTL_L2P);

			/* probe L1 parity support */
			write_c0_ecc(errctl | ERRCTL_PE);
			back_to_back_c0_hazard();
			l1parity_present = (read_c0_ecc() & ERRCTL_PE);

			/* probe L2 parity support */
			write_c0_ecc(errctl|ERRCTL_L2P);
			back_to_back_c0_hazard();
			l2parity_present = (read_c0_ecc() & ERRCTL_L2P);

			if (l1parity_present && l2parity_present) {
				if (l1parity)
					errctl |= ERRCTL_PE;
				if (l1parity ^ l2parity)
					errctl |= ERRCTL_L2P;
			} else if (l1parity_present) {
				if (l1parity)
					errctl |= ERRCTL_PE;
			} else if (l2parity_present) {
				if (l2parity)
					errctl |= ERRCTL_L2P;
			} else {
				/* No parity available */
			}

			printk(KERN_INFO "Writing ErrCtl register=%08lx\n", errctl);

			write_c0_ecc(errctl);
			back_to_back_c0_hazard();
			errctl = read_c0_ecc();
			printk(KERN_INFO "Readback ErrCtl register=%08lx\n", errctl);

			if (l1parity_present)
				printk(KERN_INFO "Cache parity protection %sabled\n",
				       (errctl & ERRCTL_PE) ? "en" : "dis");

			if (l2parity_present) {
				if (l1parity_present && l1parity)
					errctl ^= ERRCTL_L2P;
				printk(KERN_INFO "L2 cache parity protection %sabled\n",
				       (errctl & ERRCTL_L2P) ? "en" : "dis");
			}
		}
		break;

	case CPU_5KC:
	case CPU_5KE:
	case CPU_LOONGSON1:
		write_c0_ecc(0x80000000);
		back_to_back_c0_hazard();
		/* Set the PE bit (bit 31) in the c0_errctl register. */
		printk(KERN_INFO "Cache parity protection %sabled\n",
		       (read_c0_ecc() & 0x80000000) ? "en" : "dis");
		break;
	case CPU_20KC:
	case CPU_25KF:
		/* Clear the DE bit (bit 16) in the c0_status register. */
		printk(KERN_INFO "Enable cache parity protection for "
		       "MIPS 20KC/25KF CPUs.\n");
		clear_c0_status(ST0_DE);
		break;
	default:
		break;
	}
}

asmlinkage void cache_parity_error(void)
{
	const int field = 2 * sizeof(unsigned long);
	unsigned int reg_val;

	/* For the moment, report the problem and hang. */
	printk("Cache error exception:\n");
	printk("cp0_errorepc == %0*lx\n", field, 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");
	if ((cpu_has_mips_r2_r6) &&
	    ((current_cpu_data.processor_id & 0xff0000) == PRID_COMP_MIPS)) {
		pr_err("Error bits: %s%s%s%s%s%s%s%s\n",
			reg_val & (1<<29) ? "ED " : "",
			reg_val & (1<<28) ? "ET " : "",
			reg_val & (1<<27) ? "ES " : "",
			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 " : "");
	} else {
		pr_err("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%0*lx\n", field, read_c0_derraddr0());

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

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

asmlinkage void do_ftlb(void)
{
	const int field = 2 * sizeof(unsigned long);
	unsigned int reg_val;

	/* For the moment, report the problem and hang. */
	if ((cpu_has_mips_r2_r6) &&
	    ((current_cpu_data.processor_id & 0xff0000) == PRID_COMP_MIPS)) {
		pr_err("FTLB error exception, cp0_ecc=0x%08x:\n",
		       read_c0_ecc());
		pr_err("cp0_errorepc == %0*lx\n", field, read_c0_errorepc());
		reg_val = read_c0_cacheerr();
		pr_err("c0_cacheerr == %08x\n", reg_val);

		if ((reg_val & 0xc0000000) == 0xc0000000) {
			pr_err("Decoded c0_cacheerr: FTLB parity error\n");
		} else {
			pr_err("Decoded c0_cacheerr: %s cache fault in %s reference.\n",
			       reg_val & (1<<30) ? "secondary" : "primary",
			       reg_val & (1<<31) ? "data" : "insn");
		}
	} else {
		pr_err("FTLB error exception\n");
	}
	/* Just print the cacheerr bits for now */
	cache_parity_error();
}

/*
 * SDBBP EJTAG debug exception handler.
 * We skip the instruction and return to the next instruction.
 */
void ejtag_exception_handler(struct pt_regs *regs)
{
	const int field = 2 * sizeof(unsigned long);
	unsigned long depc, old_epc, old_ra;
	unsigned int debug;

	printk(KERN_DEBUG "SDBBP EJTAG debug exception - not handled yet, just ignored!\n");
	depc = read_c0_depc();
	debug = read_c0_debug();
	printk(KERN_DEBUG "c0_depc = %0*lx, DEBUG = %08x\n", field, 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;
		old_ra = regs->regs[31];
		regs->cp0_epc = depc;
		compute_return_epc(regs);
		depc = regs->cp0_epc;
		regs->cp0_epc = old_epc;
		regs->regs[31] = old_ra;
	} else
		depc += 4;
	write_c0_depc(depc);

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

/*
 * NMI exception handler.
 * No lock; only written during early bootup by CPU 0.
 */
static RAW_NOTIFIER_HEAD(nmi_chain);

int register_nmi_notifier(struct notifier_block *nb)
{
	return raw_notifier_chain_register(&nmi_chain, nb);
}

void __noreturn nmi_exception_handler(struct pt_regs *regs)
{
	char str[100];

	nmi_enter();
	raw_notifier_call_chain(&nmi_chain, 0, regs);
	bust_spinlocks(1);
	snprintf(str, 100, "CPU%d NMI taken, CP0_EPC=%lx\n",
		 smp_processor_id(), regs->cp0_epc);
	regs->cp0_epc = read_c0_errorepc();
	die(str, regs);
	nmi_exit();
}

#define VECTORSPACING 0x100	/* for EI/VI mode */

unsigned long ebase;
unsigned long exception_handlers[32];
unsigned long vi_handlers[64];

void __init *set_except_vector(int n, void *addr)
{
	unsigned long handler = (unsigned long) addr;
	unsigned long old_handler;

#ifdef CONFIG_CPU_MICROMIPS
	/*
	 * Only the TLB handlers are cache aligned with an even
	 * address. All other handlers are on an odd address and
	 * require no modification. Otherwise, MIPS32 mode will
	 * be entered when handling any TLB exceptions. That
	 * would be bad...since we must stay in microMIPS mode.
	 */
	if (!(handler & 0x1))
		handler |= 1;
#endif
	old_handler = xchg(&exception_handlers[n], handler);

	if (n == 0 && cpu_has_divec) {
#ifdef CONFIG_CPU_MICROMIPS
		unsigned long jump_mask = ~((1 << 27) - 1);
#else
		unsigned long jump_mask = ~((1 << 28) - 1);
#endif
		u32 *buf = (u32 *)(ebase + 0x200);
		unsigned int k0 = 26;
		if ((handler & jump_mask) == ((ebase + 0x200) & jump_mask)) {
			uasm_i_j(&buf, handler & ~jump_mask);
			uasm_i_nop(&buf);
		} else {
			UASM_i_LA(&buf, k0, handler);
			uasm_i_jr(&buf, k0);
			uasm_i_nop(&buf);
		}
		local_flush_icache_range(ebase + 0x200, (unsigned long)buf);
	}
	return (void *)old_handler;
}

static void do_default_vi(void)
{
	show_regs(get_irq_regs());
	panic("Caught unexpected vectored interrupt.");
}

static void *set_vi_srs_handler(int n, vi_handler_t addr, int srs)
{
	unsigned long handler;
	unsigned long old_handler = vi_handlers[n];
	int srssets = current_cpu_data.srsets;
	u16 *h;
	unsigned char *b;

	BUG_ON(!cpu_has_veic && !cpu_has_vint);

	if (addr == NULL) {
		handler = (unsigned long) do_default_vi;
		srs = 0;
	} else
		handler = (unsigned long) addr;
	vi_handlers[n] = handler;

	b = (unsigned char *)(ebase + 0x200 + n*VECTORSPACING);

	if (srs >= srssets)
		panic("Shadow register set %d not supported", srs);

	if (cpu_has_veic) {
		if (board_bind_eic_interrupt)
			board_bind_eic_interrupt(n, srs);
	} else if (cpu_has_vint) {
		/* SRSMap is only defined if shadow sets are implemented */
		if (srssets > 1)
			change_c0_srsmap(0xf << n*4, srs << n*4);
	}

	if (srs == 0) {
		/*
		 * If no shadow set is selected then use the default handler
		 * that does normal register saving and standard interrupt exit
		 */
		extern char except_vec_vi, except_vec_vi_lui;
		extern char except_vec_vi_ori, except_vec_vi_end;
		extern char rollback_except_vec_vi;
		char *vec_start = using_rollback_handler() ?
			&rollback_except_vec_vi : &except_vec_vi;
#if defined(CONFIG_CPU_MICROMIPS) || defined(CONFIG_CPU_BIG_ENDIAN)
		const int lui_offset = &except_vec_vi_lui - vec_start + 2;
		const int ori_offset = &except_vec_vi_ori - vec_start + 2;
#else
		const int lui_offset = &except_vec_vi_lui - vec_start;
		const int ori_offset = &except_vec_vi_ori - vec_start;
#endif
		const int handler_len = &except_vec_vi_end - vec_start;

		if (handler_len > VECTORSPACING) {
			/*
			 * Sigh... panicing won't help as the console
			 * is probably not configured :(
			 */
			panic("VECTORSPACING too small");
		}

		set_handler(((unsigned long)b - ebase), vec_start,
#ifdef CONFIG_CPU_MICROMIPS
				(handler_len - 1));
#else
				handler_len);
#endif
		h = (u16 *)(b + lui_offset);
		*h = (handler >> 16) & 0xffff;
		h = (u16 *)(b + ori_offset);
		*h = (handler & 0xffff);
		local_flush_icache_range((unsigned long)b,
					 (unsigned long)(b+handler_len));
	}
	else {
		/*
		 * In other cases jump directly to the interrupt handler. It
		 * is the handler's responsibility to save registers if required
		 * (eg hi/lo) and return from the exception using "eret".
		 */
		u32 insn;

		h = (u16 *)b;
		/* j handler */
#ifdef CONFIG_CPU_MICROMIPS
		insn = 0xd4000000 | (((u32)handler & 0x07ffffff) >> 1);
#else
		insn = 0x08000000 | (((u32)handler & 0x0fffffff) >> 2);
#endif