Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2562 insertions, 0 deletions

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
new file mode 100644
index 0000000000..246c6a6b02
--- /dev/null
+++ b/arch/mips/kernel/traps.c
@@ -0,0 +1,2562 @@
+/*
+ * 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, 06 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) 2002, 2003, 2004, 2005, 2007  Maciej W. Rozycki
+ * Copyright (C) 2000, 2001, 2012 MIPS Technologies, Inc.  All rights reserved.
+ * Copyright (C) 2014, Imagination Technologies Ltd.
+ */
+#include <linux/bitops.h>
+#include <linux/bug.h>
+#include <linux/compiler.h>
+#include <linux/context_tracking.h>
+#include <linux/cpu_pm.h>
+#include <linux/kexec.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/extable.h>
+#include <linux/mm.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/debug.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+#include <linux/kallsyms.h>
+#include <linux/memblock.h>
+#include <linux/interrupt.h>
+#include <linux/ptrace.h>
+#include <linux/kgdb.h>
+#include <linux/kdebug.h>
+#include <linux/kprobes.h>
+#include <linux/notifier.h>
+#include <linux/kdb.h>
+#include <linux/irq.h>
+#include <linux/perf_event.h>
+
+#include <asm/addrspace.h>
+#include <asm/bootinfo.h>
+#include <asm/branch.h>
+#include <asm/break.h>
+#include <asm/cop2.h>
+#include <asm/cpu.h>
+#include <asm/cpu-type.h>
+#include <asm/dsp.h>
+#include <asm/fpu.h>
+#include <asm/fpu_emulator.h>
+#include <asm/idle.h>
+#include <asm/isa-rev.h>
+#include <asm/mips-cps.h>
+#include <asm/mips-r2-to-r6-emul.h>
+#include <asm/mipsregs.h>
+#include <asm/mipsmtregs.h>
+#include <asm/module.h>
+#include <asm/msa.h>
+#include <asm/ptrace.h>
+#include <asm/sections.h>
+#include <asm/siginfo.h>
+#include <asm/tlbdebug.h>
+#include <asm/traps.h>
+#include <linux/uaccess.h>
+#include <asm/watch.h>
+#include <asm/mmu_context.h>
+#include <asm/types.h>
+#include <asm/stacktrace.h>
+#include <asm/tlbex.h>
+#include <asm/uasm.h>
+
+#include <asm/mach-loongson64/cpucfg-emul.h>
+
+#include "access-helper.h"
+
+extern void check_wait(void);
+extern asmlinkage void rollback_handle_int(void);
+extern asmlinkage void handle_int(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_ri_rdhwr_tlbp(void);
+extern asmlinkage void handle_ri_rdhwr(void);
+extern asmlinkage void handle_cpu(void);
+extern asmlinkage void handle_ov(void);
+extern asmlinkage void handle_tr(void);
+extern asmlinkage void handle_msa_fpe(void);
+extern asmlinkage void handle_fpe(void);
+extern asmlinkage void handle_ftlb(void);
+extern asmlinkage void handle_gsexc(void);
+extern asmlinkage void handle_msa(void);
+extern asmlinkage void handle_mdmx(void);
+extern asmlinkage void handle_watch(void);
+extern asmlinkage void handle_mt(void);
+extern asmlinkage void handle_dsp(void);
+extern asmlinkage void handle_mcheck(void);
+extern asmlinkage void handle_reserved(void);
+extern void tlb_do_page_fault_0(void);
+
+void (*board_be_init)(void);
+static int (*board_be_handler)(struct pt_regs *regs, int is_fixup);
+void (*board_nmi_handler_setup)(void);
+void (*board_ejtag_handler_setup)(void);
+void (*board_bind_eic_interrupt)(int irq, int regset);
+void (*board_ebase_setup)(void);
+void(*board_cache_error_setup)(void);
+
+void mips_set_be_handler(int (*handler)(struct pt_regs *regs, int is_fixup))
+{
+	board_be_handler = handler;
+}
+EXPORT_SYMBOL_GPL(mips_set_be_handler);
+
+static void show_raw_backtrace(unsigned long reg29, const char *loglvl,
+			       bool user)
+{
+	unsigned long *sp = (unsigned long *)(reg29 & ~3);
+	unsigned long addr;
+
+	printk("%sCall Trace:", loglvl);
+#ifdef CONFIG_KALLSYMS
+	printk("%s\n", loglvl);
+#endif
+	while (!kstack_end(sp)) {
+		if (__get_addr(&addr, sp++, user)) {
+			printk("%s (Bad stack address)", loglvl);
+			break;
+		}
+		if (__kernel_text_address(addr))
+			print_ip_sym(loglvl, addr);
+	}
+	printk("%s\n", loglvl);
+}
+
+#ifdef CONFIG_KALLSYMS
+int raw_show_trace;
+static int __init set_raw_show_trace(char *str)
+{
+	raw_show_trace = 1;
+	return 1;
+}
+__setup("raw_show_trace", set_raw_show_trace);
+#endif
+
+static void show_backtrace(struct task_struct *task, const struct pt_regs *regs,
+			   const char *loglvl, bool user)
+{
+	unsigned long sp = regs->regs[29];
+	unsigned long ra = regs->regs[31];
+	unsigned long pc = regs->cp0_epc;
+
+	if (!task)
+		task = current;
+
+	if (raw_show_trace || user_mode(regs) || !__kernel_text_address(pc)) {
+		show_raw_backtrace(sp, loglvl, user);
+		return;
+	}
+	printk("%sCall Trace:\n", loglvl);
+	do {
+		print_ip_sym(loglvl, pc);
+		pc = unwind_stack(task, &sp, pc, &ra);
+	} while (pc);
+	pr_cont("\n");
+}
+
+/*
+ * This routine abuses get_user()/put_user() to reference pointers
+ * with at least a bit of error checking ...
+ */
+static void show_stacktrace(struct task_struct *task,
+	const struct pt_regs *regs, const char *loglvl, bool user)
+{
+	const int field = 2 * sizeof(unsigned long);
+	unsigned long stackdata;
+	int i;
+	unsigned long *sp = (unsigned long *)regs->regs[29];
+
+	printk("%sStack :", loglvl);
+	i = 0;
+	while ((unsigned long) sp & (PAGE_SIZE - 1)) {
+		if (i && ((i % (64 / field)) == 0)) {
+			pr_cont("\n");
+			printk("%s       ", loglvl);
+		}
+		if (i > 39) {
+			pr_cont(" ...");
+			break;
+		}
+
+		if (__get_addr(&stackdata, sp++, user)) {
+			pr_cont(" (Bad stack address)");
+			break;
+		}
+
+		pr_cont(" %0*lx", field, stackdata);
+		i++;
+	}
+	pr_cont("\n");
+	show_backtrace(task, regs, loglvl, user);
+}
+
+void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
+{
+	struct pt_regs regs;
+
+	regs.cp0_status = KSU_KERNEL;
+	if (sp) {
+		regs.regs[29] = (unsigned long)sp;
+		regs.regs[31] = 0;
+		regs.cp0_epc = 0;
+	} else {
+		if (task && task != current) {
+			regs.regs[29] = task->thread.reg29;
+			regs.regs[31] = 0;
+			regs.cp0_epc = task->thread.reg31;
+		} else {
+			prepare_frametrace(&regs);
+		}
+	}
+	show_stacktrace(task, &regs, loglvl, false);
+}
+
+static void show_code(void *pc, bool user)
+{
+	long i;
+	unsigned short *pc16 = NULL;
+
+	printk("Code:");
+
+	if ((unsigned long)pc & 1)
+		pc16 = (u16 *)((unsigned long)pc & ~1);
+
+	for(i = -3 ; i < 6 ; i++) {
+		if (pc16) {
+			u16 insn16;
+
+			if (__get_inst16(&insn16, pc16 + i, user))
+				goto bad_address;
+
+			pr_cont("%c%04x%c", (i?' ':'<'), insn16, (i?' ':'>'));
+		} else {
+			u32 insn32;
+
+			if (__get_inst32(&insn32, (u32 *)pc + i, user))
+				goto bad_address;
+
+			pr_cont("%c%08x%c", (i?' ':'<'), insn32, (i?' ':'>'));
+		}
+	}
+	pr_cont("\n");
+	return;
+
+bad_address:
+	pr_cont(" (Bad address in epc)\n\n");
+}
+
+static void __show_regs(const struct pt_regs *regs)
+{
+	const int field = 2 * sizeof(unsigned long);
+	unsigned int cause = regs->cp0_cause;
+	unsigned int exccode;
+	int i;
+
+	show_regs_print_info(KERN_DEFAULT);
+
+	/*
+	 * Saved main processor registers
+	 */
+	for (i = 0; i < 32; ) {
+		if ((i % 4) == 0)
+			printk("$%2d   :", i);
+		if (i == 0)
+			pr_cont(" %0*lx", field, 0UL);
+		else if (i == 26 || i == 27)
+			pr_cont(" %*s", field, "");
+		else
+			pr_cont(" %0*lx", field, regs->regs[i]);
+
+		i++;
+		if ((i % 4) == 0)
+			pr_cont("\n");
+	}
+
+#ifdef CONFIG_CPU_HAS_SMARTMIPS
+	printk("Acx    : %0*lx\n", field, regs->acx);
+#endif
+	if (MIPS_ISA_REV < 6) {
+		printk("Hi    : %0*lx\n", field, regs->hi);
+		printk("Lo    : %0*lx\n", field, regs->lo);
+	}
+
+	/*
+	 * Saved cp0 registers
+	 */
+	printk("epc   : %0*lx %pS\n", field, regs->cp0_epc,
+	       (void *) regs->cp0_epc);
+	printk("ra    : %0*lx %pS\n", field, regs->regs[31],
+	       (void *) regs->regs[31]);
+
+	printk("Status: %08x	", (uint32_t) regs->cp0_status);
+
+	if (cpu_has_3kex) {
+		if (regs->cp0_status & ST0_KUO)
+			pr_cont("KUo ");
+		if (regs->cp0_status & ST0_IEO)
+			pr_cont("IEo ");
+		if (regs->cp0_status & ST0_KUP)
+			pr_cont("KUp ");
+		if (regs->cp0_status & ST0_IEP)
+			pr_cont("IEp ");
+		if (regs->cp0_status & ST0_KUC)
+			pr_cont("KUc ");
+		if (regs->cp0_status & ST0_IEC)
+			pr_cont("IEc ");
+	} else if (cpu_has_4kex) {
+		if (regs->cp0_status & ST0_KX)
+			pr_cont("KX ");
+		if (regs->cp0_status & ST0_SX)
+			pr_cont("SX ");
+		if (regs->cp0_status & ST0_UX)
+			pr_cont("UX ");
+		switch (regs->cp0_status & ST0_KSU) {
+		case KSU_USER:
+			pr_cont("USER ");
+			break;
+		case KSU_SUPERVISOR:
+			pr_cont("SUPERVISOR ");
+			break;
+		case KSU_KERNEL:
+			pr_cont("KERNEL ");
+			break;
+		default:
+			pr_cont("BAD_MODE ");
+			break;
+		}
+		if (regs->cp0_status & ST0_ERL)
+			pr_cont("ERL ");
+		if (regs->cp0_status & ST0_EXL)
+			pr_cont("EXL ");
+		if (regs->cp0_status & ST0_IE)
+			pr_cont("IE ");
+	}
+	pr_cont("\n");
+
+	exccode = (cause & CAUSEF_EXCCODE) >> CAUSEB_EXCCODE;
+	printk("Cause : %08x (ExcCode %02x)\n", cause, exccode);
+
+	if (1 <= exccode && exccode <= 5)
+		printk("BadVA : %0*lx\n", field, regs->cp0_badvaddr);
+
+	printk("PrId  : %08x (%s)\n", read_c0_prid(),
+	       cpu_name_string());
+}
+
+/*
+ * FIXME: really the generic show_regs should take a const pointer argument.
+ */
+void show_regs(struct pt_regs *regs)
+{
+	__show_regs(regs);
+	dump_stack();
+}
+
+void show_registers(struct pt_regs *regs)
+{
+	const int field = 2 * sizeof(unsigned long);
+
+	__show_regs(regs);
+	print_modules();
+	printk("Process %s (pid: %d, threadinfo=%p, task=%p, tls=%0*lx)\n",
+	       current->comm, current->pid, current_thread_info(), current,
+	      field, current_thread_info()->tp_value);
+	if (cpu_has_userlocal) {
+		unsigned long tls;
+
+		tls = read_c0_userlocal();
+		if (tls != current_thread_info()->tp_value)
+			printk("*HwTLS: %0*lx\n", field, tls);
+	}
+
+	show_stacktrace(current, regs, KERN_DEFAULT, user_mode(regs));
+	show_code((void *)regs->cp0_epc, user_mode(regs));
+	printk("\n");
+}
+
+static DEFINE_RAW_SPINLOCK(die_lock);
+
+void __noreturn die(const char *str, struct pt_regs *regs)
+{
+	static int die_counter;
+	int sig = SIGSEGV;
+
+	oops_enter();
+
+	if (notify_die(DIE_OOPS, str, regs, 0, current->thread.trap_nr,
+		       SIGSEGV) == NOTIFY_STOP)
+		sig = 0;
+
+	console_verbose();
+	raw_spin_lock_irq(&die_lock);
+	bust_spinlocks(1);
+
+	printk("%s[#%d]:\n", str, ++die_counter);
+	show_registers(regs);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
+	raw_spin_unlock_irq(&die_lock);
+
+	oops_exit();
+
+	if (in_interrupt())
+		panic("Fatal exception in interrupt");
+
+	if (panic_on_oops)
+		panic("Fatal exception");
+
+	if (regs && kexec_should_crash(current))
+		crash_kexec(regs);
+
+	make_task_dead(sig);
+}
+
+extern struct exception_table_entry __start___dbe_table[];
+extern struct exception_table_entry __stop___dbe_table[];
+
+__asm__(
+"	.section	__dbe_table, \"a\"\n"
+"	.previous			\n");
+
+/* Given an address, look for it in the exception tables. */
+static const struct exception_table_entry *search_dbe_tables(unsigned long addr)
+{
+	const struct exception_table_entry *e;
+
+	e = search_extable(__start___dbe_table,
+			   __stop___dbe_table - __start___dbe_table, addr);
+	if (!e)
+		e = search_module_dbetables(addr);
+	return e;
+}
+
+asmlinkage void do_be(struct pt_regs *regs)
+{
+	const int field = 2 * sizeof(unsigned long);
+	const struct exception_table_entry *fixup = NULL;
+	int data = regs->cp0_cause & 4;
+	int action = MIPS_BE_FATAL;
+	enum ctx_state prev_state;
+
+	prev_state = exception_enter();
+	/* XXX For now.	 Fixme, this searches the wrong table ...  */
+	if (data && !user_mode(regs))
+		fixup = search_dbe_tables(exception_epc(regs));
+
+	if (fixup)
+		action = MIPS_BE_FIXUP;
+
+	if (board_be_handler)
+		action = board_be_handler(regs, fixup != NULL);
+	else
+		mips_cm_error_report();
+
+	switch (action) {
+	case MIPS_BE_DISCARD:
+		goto out;
+	case MIPS_BE_FIXUP:
+		if (fixup) {
+			regs->cp0_epc = fixup->nextinsn;
+			goto out;
+		}
+		break;
+	default:
+		break;
+	}
+
+	/*
+	 * Assume it would be too dangerous to continue ...
+	 */
+	printk(KERN_ALERT "%s bus error, epc == %0*lx, ra == %0*lx\n",
+	       data ? "Data" : "Instruction",
+	       field, regs->cp0_epc, field, regs->regs[31]);
+	if (notify_die(DIE_OOPS, "bus error", regs, 0, current->thread.trap_nr,
+		       SIGBUS) == NOTIFY_STOP)
+		goto out;
+
+	die_if_kernel("Oops", regs);
+	force_sig(SIGBUS);
+
+out:
+	exception_exit(prev_state);
+}
+
+/*
+ * ll/sc, rdhwr, sync emulation
+ */
+
+#define OPCODE 0xfc000000
+#define BASE   0x03e00000
+#define RT     0x001f0000
+#define OFFSET 0x0000ffff
+#define LL     0xc0000000
+#define SC     0xe0000000
+#define SPEC0  0x00000000
+#define SPEC3  0x7c000000
+#define RD     0x0000f800
+#define FUNC   0x0000003f
+#define SYNC   0x0000000f
+#define RDHWR  0x0000003b
+
+/*  microMIPS definitions   */
+#define MM_POOL32A_FUNC 0xfc00ffff
+#define MM_RDHWR        0x00006b3c
+#define MM_RS           0x001f0000
+#define MM_RT           0x03e00000
+
+/*
+ * The ll_bit is cleared by r*_switch.S
+ */
+
+unsigned int ll_bit;
+struct task_struct *ll_task;
+
+static inline int simulate_ll(struct pt_regs *regs, unsigned int opcode)
+{
+	unsigned long value, __user *vaddr;
+	long offset;
+
+	/*
+	 * 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 __user *)
+		((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
+
+	if ((unsigned long)vaddr & 3)
+		return SIGBUS;
+	if (get_user(value, vaddr))
+		return SIGSEGV;
+
+	preempt_disable();
+
+	if (ll_task == NULL || ll_task == current) {
+		ll_bit = 1;
+	} else {
+		ll_bit = 0;
+	}
+	ll_task = current;
+
+	preempt_enable();
+
+	regs->regs[(opcode & RT) >> 16] = value;
+
+	return 0;
+}
+
+static inline int simulate_sc(struct pt_regs *regs, unsigned int opcode)
+{
+	unsigned long __user *vaddr;
+	unsigned long reg;
+	long offset;
+
+	/*
+	 * 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 __user *)
+		((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
+	reg = (opcode & RT) >> 16;
+
+	if ((unsigned long)vaddr & 3)
+		return SIGBUS;
+
+	preempt_disable();
+
+	if (ll_bit == 0 || ll_task != current) {
+		regs->regs[reg] = 0;
+		preempt_enable();
+		return 0;
+	}
+
+	preempt_enable();
+
+	if (put_user(regs->regs[reg], vaddr))
+		return SIGSEGV;
+
+	regs->regs[reg] = 1;
+
+	return 0;
+}
+
+/*
+ * 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 int simulate_llsc(struct pt_regs *regs, unsigned int opcode)
+{
+	if ((opcode & OPCODE) == LL) {
+		perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS,
+				1, regs, 0);
+		return simulate_ll(regs, opcode);
+	}
+	if ((opcode & OPCODE) == SC) {
+		perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS,
+				1, regs, 0);
+		return simulate_sc(regs, opcode);
+	}
+
+	return -1;			/* Must be something else ... */
+}
+
+/*
+ * Simulate trapping 'rdhwr' instructions to provide user accessible
+ * registers not implemented in hardware.
+ */
+static int simulate_rdhwr(struct pt_regs *regs, int rd, int rt)
+{
+	struct thread_info *ti = task_thread_info(current);
+
+	perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS,
+			1, regs, 0);
+	switch (rd) {
+	case MIPS_HWR_CPUNUM:		/* CPU number */
+		regs->regs[rt] = smp_processor_id();
+		return 0;
+	case MIPS_HWR_SYNCISTEP:	/* SYNCI length */
+		regs->regs[rt] = min(current_cpu_data.dcache.linesz,
+				     current_cpu_data.icache.linesz);
+		return 0;
+	case MIPS_HWR_CC:		/* Read count register */
+		regs->regs[rt] = read_c0_count();
+		return 0;
+	case MIPS_HWR_CCRES:		/* Count register resolution */
+		switch (current_cpu_type()) {
+		case CPU_20KC:
+		case CPU_25KF:
+			regs->regs[rt] = 1;
+			break;
+		default:
+			regs->regs[rt] = 2;
+		}
+		return 0;
+	case MIPS_HWR_ULR:		/* Read UserLocal register */
+		regs->regs[rt] = ti->tp_value;
+		return 0;
+	default:
+		return -1;
+	}
+}
+
+static int simulate_rdhwr_normal(struct pt_regs *regs, unsigned int opcode)
+{
+	if ((opcode & OPCODE) == SPEC3 && (opcode & FUNC) == RDHWR) {
+		int rd = (opcode & RD) >> 11;
+		int rt = (opcode & RT) >> 16;
+
+		simulate_rdhwr(regs, rd, rt);
+		return 0;
+	}
+
+	/* Not ours.  */
+	return -1;
+}
+
+static int simulate_rdhwr_mm(struct pt_regs *regs, unsigned int opcode)
+{
+	if ((opcode & MM_POOL32A_FUNC) == MM_RDHWR) {
+		int rd = (opcode & MM_RS) >> 16;
+		int rt = (opcode & MM_RT) >> 21;
+		simulate_rdhwr(regs, rd, rt);
+		return 0;
+	}
+
+	/* Not ours.  */
+	return -1;
+}
+
+static int simulate_sync(struct pt_regs *regs, unsigned int opcode)
+{
+	if ((opcode & OPCODE) == SPEC0 && (opcode & FUNC) == SYNC) {
+		perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS,
+				1, regs, 0);
+		return 0;
+	}
+
+	return -1;			/* Must be something else ... */
+}
+
+/*
+ * Loongson-3 CSR instructions emulation
+ */
+
+#ifdef CONFIG_CPU_LOONGSON3_CPUCFG_EMULATION
+
+#define LWC2             0xc8000000
+#define RS               BASE
+#define CSR_OPCODE2      0x00000118
+#define CSR_OPCODE2_MASK 0x000007ff
+#define CSR_FUNC_MASK    RT
+#define CSR_FUNC_CPUCFG  0x8
+
+static int simulate_loongson3_cpucfg(struct pt_regs *regs,
+				     unsigned int opcode)
+{
+	int op = opcode & OPCODE;
+	int op2 = opcode & CSR_OPCODE2_MASK;
+	int csr_func = (opcode & CSR_FUNC_MASK) >> 16;
+
+	if (op == LWC2 && op2 == CSR_OPCODE2 && csr_func == CSR_FUNC_CPUCFG) {
+		int rd = (opcode & RD) >> 11;
+		int rs = (opcode & RS) >> 21;
+		__u64 sel = regs->regs[rs];
+
+		perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0);
+
+		/* Do not emulate on unsupported core models. */
+		preempt_disable();
+		if (!loongson3_cpucfg_emulation_enabled(&current_cpu_data)) {
+			preempt_enable();
+			return -1;
+		}
+		regs->regs[rd] = loongson3_cpucfg_read_synthesized(
+			&current_cpu_data, sel);
+		preempt_enable();
+		return 0;
+	}
+
+	/* Not ours.  */
+	return -1;
+}
+#endif /* CONFIG_CPU_LOONGSON3_CPUCFG_EMULATION */
+
+asmlinkage void do_ov(struct pt_regs *regs)
+{
+	enum ctx_state prev_state;
+
+	prev_state = exception_enter();
+	die_if_kernel("Integer overflow", regs);
+
+	force_sig_fault(SIGFPE, FPE_INTOVF, (void __user *)regs->cp0_epc);
+	exception_exit(prev_state);
+}
+
+#ifdef CONFIG_MIPS_FP_SUPPORT
+
+/*
+ * Send SIGFPE according to FCSR Cause bits, which must have already
+ * been masked against Enable bits.  This is impotant as Inexact can
+ * happen together with Overflow or Underflow, and `ptrace' can set
+ * any bits.
+ */
+void force_fcr31_sig(unsigned long fcr31, void __user *fault_addr,
+		     struct task_struct *tsk)
+{
+	int si_code = FPE_FLTUNK;
+
+	if (fcr31 & FPU_CSR_INV_X)
+		si_code = FPE_FLTINV;
+	else if (fcr31 & FPU_CSR_DIV_X)
+		si_code = FPE_FLTDIV;
+	else if (fcr31 & FPU_CSR_OVF_X)
+		si_code = FPE_FLTOVF;
+	else if (fcr31 & FPU_CSR_UDF_X)
+		si_code = FPE_FLTUND;
+	else if (fcr31 & FPU_CSR_INE_X)
+		si_code = FPE_FLTRES;
+
+	force_sig_fault_to_task(SIGFPE, si_code, fault_addr, tsk);
+}
+
+int process_fpemu_return(int sig, void __user *fault_addr, unsigned long fcr31)
+{
+	int si_code;
+
+	switch (sig) {
+	case 0:
+		return 0;
+
+	case SIGFPE:
+		force_fcr31_sig(fcr31, fault_addr, current);
+		return 1;
+
+	case SIGBUS:
+		force_sig_fault(SIGBUS, BUS_ADRERR, fault_addr);
+		return 1;
+
+	case SIGSEGV:
+		mmap_read_lock(current->mm);
+		if (vma_lookup(current->mm, (unsigned long)fault_addr))
+			si_code = SEGV_ACCERR;
+		else
+			si_code = SEGV_MAPERR;
+		mmap_read_unlock(current->mm);
+		force_sig_fault(SIGSEGV, si_code, fault_addr);
+		return 1;
+
+	default:
+		force_sig(sig);
+		return 1;
+	}
+}
+
+static int simulate_fp(struct pt_regs *regs, unsigned int opcode,
+		       unsigned long old_epc, unsigned long old_ra)
+{
+	union mips_instruction inst = { .word = opcode };
+	void __user *fault_addr;
+	unsigned long fcr31;
+	int sig;
+
+	/* If it's obviously not an FP instruction, skip it */
+	switch (inst.i_format.opcode) {
+	case cop1_op:
+	case cop1x_op:
+	case lwc1_op:
+	case ldc1_op:
+	case swc1_op:
+	case sdc1_op:
+		break;
+
+	default:
+		return -1;
+	}
+
+	/*
+	 * do_ri skipped over the instruction via compute_return_epc, undo
+	 * that for the FPU emulator.
+	 */
+	regs->cp0_epc = old_epc;
+	regs->regs[31] = old_ra;
+
+	/* Run the emulator */
+	sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1,
+				       &fault_addr);
+
+	/*
+	 * We can't allow the emulated instruction to leave any
+	 * enabled Cause bits set in $fcr31.
+	 */
+	fcr31 = mask_fcr31_x(current->thread.fpu.fcr31);
+	current->thread.fpu.fcr31 &= ~fcr31;
+
+	/* Restore the hardware register state */
+	own_fpu(1);
+
+	/* Send a signal if required.  */
+	process_fpemu_return(sig, fault_addr, fcr31);
+
+	return 0;
+}
+
+/*
+ * XXX Delayed fp exceptions when doing a lazy ctx switch XXX
+ */
+asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
+{
+	enum ctx_state prev_state;
+	void __user *fault_addr;
+	int sig;
+
+	prev_state = exception_enter();
+	if (notify_die(DIE_FP, "FP exception", regs, 0, current->thread.trap_nr,
+		       SIGFPE) == NOTIFY_STOP)
+		goto out;
+
+	/* Clear FCSR.Cause before enabling interrupts */
+	write_32bit_cp1_register(CP1_STATUS, fcr31 & ~mask_fcr31_x(fcr31));
+	local_irq_enable();
+
+	die_if_kernel("FP exception in kernel code", regs);
+
+	if (fcr31 & FPU_CSR_UNI_X) {
+		/*
+		 * 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.
+		 */
+
+		/* Run the emulator */
+		sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1,
+					       &fault_addr);
+
+		/*
+		 * We can't allow the emulated instruction to leave any
+		 * enabled Cause bits set in $fcr31.
+		 */
+		fcr31 = mask_fcr31_x(current->thread.fpu.fcr31);
+		current->thread.fpu.fcr31 &= ~fcr31;
+
+		/* Restore the hardware register state */
+		own_fpu(1);	/* Using the FPU again.	 */
+	} else {
+		sig = SIGFPE;
+		fault_addr = (void __user *) regs->cp0_epc;
+	}
+
+	/* Send a signal if required.  */
+	process_fpemu_return(sig, fault_addr, fcr31);
+
+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_mask, &mt_fpu_cpumask)) {
+			cpumask_t tmask;
+
+			current->thread.user_cpus_allowed
+				= current->cpus_mask;
+			cpumask_and(&tmask, &current->cpus_mask,
+				    &mt_fpu_cpumask);
+			set_cpus_allowed_ptr(current, &tmask);
+			set_thread_flag(TIF_FPUBOUND);
+		}
+	}
+#endif /* CONFIG_MIPS_MT_FPAFF */
+}
+
+#else /* !CONFIG_MIPS_FP_SUPPORT */
+
+static int simulate_fp(struct pt_regs *regs, unsigned int opcode,
+		       unsigned long old_epc, unsigned long old_ra)
+{
+	return -1;
+}
+
+#endif /* !CONFIG_MIPS_FP_SUPPORT */
+
+void do_trap_or_bp(struct pt_regs *regs, unsigned int code, int si_code,
+	const char *str)
+{
+	char b[40];
+
+#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
+	if (kgdb_ll_trap(DIE_TRAP, str, regs, code, current->thread.trap_nr,
+			 SIGTRAP) == NOTIFY_STOP)
+		return;
+#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
+
+	if (notify_die(DIE_TRAP, str, regs, code, current->thread.trap_nr,
+		       SIGTRAP) == NOTIFY_STOP)
+		return;
+
+	/*
+	 * A short test says that IRIX 5.3 sends SIGTRAP for all trap
+	 * insns, even for trap and break codes that indicate arithmetic
+	 * failures.  Weird ...
+	 * But should we continue the brokenness???  --macro
+	 */
+	switch (code) {
+	case BRK_OVERFLOW:
+	case BRK_DIVZERO:
+		scnprintf(b, sizeof(b), "%s instruction in kernel code", str);
+		die_if_kernel(b, regs);
+		force_sig_fault(SIGFPE,
+				code == BRK_DIVZERO ? FPE_INTDIV : FPE_INTOVF,
+				(void __user *) regs->cp0_epc);
+		break;
+	case BRK_BUG:
+		die_if_kernel("Kernel bug detected", regs);
+		force_sig(SIGTRAP);
+		break;
+	case BRK_MEMU:
+		/*
+		 * This breakpoint code is used by the FPU emulator to retake
+		 * control of the CPU after executing the instruction from the
+		 * delay slot of an emulated branch.
+		 *
+		 * Terminate if exception was recognized as a delay slot return
+		 * otherwise handle as normal.
+		 */
+		if (do_dsemulret(regs))
+			return;
+
+		die_if_kernel("Math emu break/trap", regs);
+		force_sig(SIGTRAP);
+		break;
+	default:
+		scnprintf(b, sizeof(b), "%s instruction in kernel code", str);
+		die_if_kernel(b, regs);
+		if (si_code) {
+			force_sig_fault(SIGTRAP, si_code, NULL);
+		} else {
+			force_sig(SIGTRAP);
+		}
+	}
+}
+
+asmlinkage void do_bp(struct pt_regs *regs)
+{
+	unsigned long epc = msk_isa16_mode(exception_epc(regs));
+	unsigned int opcode, bcode;
+	enum ctx_state prev_state;
+	bool user = user_mode(regs);
+
+	prev_state = exception_enter();
+	current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
+	if (get_isa16_mode(regs->cp0_epc)) {
+		u16 instr[2];
+
+		if (__get_inst16(&instr[0], (u16 *)epc, user))
+			goto out_sigsegv;
+
+		if (!cpu_has_mmips) {
+			/* MIPS16e mode */
+			bcode = (instr[0] >> 5) & 0x3f;
+		} else if (mm_insn_16bit(instr[0])) {
+			/* 16-bit microMIPS BREAK */
+			bcode = instr[0] & 0xf;
+		} else {
+			/* 32-bit microMIPS BREAK */
+			if (__get_inst16(&instr[1], (u16 *)(epc + 2), user))
+				goto out_sigsegv;
+			opcode = (instr[0] << 16) | instr[1];
+			bcode = (opcode >> 6) & ((1 << 20) - 1);
+		}
+	} else {
+		if (__get_inst32(&opcode, (u32 *)epc, user))
+			goto out_sigsegv;
+		bcode = (opcode >> 6) & ((1 << 20) - 1);
+	}
+
+	/*
+	 * 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, but not always, grrr...
+	 * We handle both cases with a simple heuristics.  --macro
+	 */
+	if (bcode >= (1 << 10))
+		bcode = ((bcode & ((1 << 10) - 1)) << 10) | (bcode >> 10);
+
+	/*
+	 * notify the kprobe handlers, if instruction is likely to
+	 * pertain to them.
+	 */
+	switch (bcode) {
+	case BRK_UPROBE:
+		if (notify_die(DIE_UPROBE, "uprobe", regs, bcode,
+			       current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
+			goto out;
+		else
+			break;
+	case BRK_UPROBE_XOL:
+		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:
+	exception_exit(prev_state);
+	return;
+
+out_sigsegv:
+	force_sig(SIGSEGV);
+	goto out;
+}
+
+asmlinkage void do_tr(struct pt_regs *regs)
+{
+	u32 opcode, tcode = 0;
+	enum ctx_state prev_state;
+	u16 instr[2];
+	bool user = user_mode(regs);
+	unsigned long epc = msk_isa16_mode(exception_epc(regs));
+
+	prev_state = exception_enter();
+	current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
+	if (get_isa16_mode(regs->cp0_epc)) {
+		if (__get_inst16(&instr[0], (u16 *)(epc + 0), user) ||
+		    __get_inst16(&instr[1], (u16 *)(epc + 2), user))
+			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_inst32(&opcode, (u32 *)epc, user))
+			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:
+	exception_exit(prev_state);
+	return;
+
+out_sigsegv:
+	force_sig(SIGSEGV);
+	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:
+			return;
+		case SIGILL:
+			goto no_r2_instr;
+		default:
+			process_fpemu_return(status,
+					     &current->thread.cp0_baduaddr,
+					     fcr31);
+			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)) {
+		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);
+
+#ifdef CONFIG_CPU_LOONGSON3_CPUCFG_EMULATION
+		if (status < 0)
+			status = simulate_loongson3_cpucfg(regs, opcode);
+#endif
+	} else if (cpu_has_mmips) {
+		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);
+	}
+
+	if (status < 0)
+		status = SIGILL;
+
+	if (unlikely(status > 0)) {
+		regs->cp0_epc = old_epc;		/* Undo skip-over.  */
+		regs->regs[31] = old31;
+		force_sig(status);
+	}
+
+out:
+	exception_exit(prev_state);
+}
+
+/*
+ * 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);
+
+	return NOTIFY_OK;
+}
+
+#ifdef CONFIG_MIPS_FP_SUPPORT
+
+static int enable_restore_fp_context(int msa)
+{
+	int err, was_fpu_owner, prior_msa;
+	bool first_fp;
+
+	/* Initialize context if it hasn't been used already */
+	first_fp = init_fp_ctx(current);
+
+	if (first_fp) {
+		preempt_disable();
+		err = own_fpu_inatomic(1);
+		if (msa && !err) {
+			enable_msa();
+			/*
+			 * with MSA enabled, userspace can see MSACSR
+			 * and MSA regs, but the values in them are from
+			 * other task before current task, restore them
+			 * from saved fp/msa context
+			 */
+			write_msa_csr(current->thread.fpu.msacsr);
+			/*
+			 * own_fpu_inatomic(1) just restore low 64bit,
+			 * fix the high 64bit
+			 */
+			init_msa_upper();
+			set_thread_flag(TIF_USEDMSA);
+			set_thread_flag(TIF_MSA_CTX_LIVE);
+		}
+		preempt_enable();
+		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;
+}
+
+#else /* !CONFIG_MIPS_FP_SUPPORT */
+
+static int enable_restore_fp_context(int msa)
+{
+	return SIGILL;
+}
+
+#endif /* CONFIG_MIPS_FP_SUPPORT */
+
+asmlinkage void do_cpu(struct pt_regs *regs)
+{
+	enum ctx_state prev_state;
+	unsigned int __user *epc;
+	unsigned long old_epc, old31;
+	unsigned int opcode;
+	unsigned int cpid;
+	int status;
+
+	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);
+		}
+
+		break;
+
+#ifdef CONFIG_MIPS_FP_SUPPORT
+	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);
+			break;
+		}
+		fallthrough;
+	case 1: {
+		void __user *fault_addr;
+		unsigned long fcr31;
+		int err, sig;
+
+		err = enable_restore_fp_context(0);
+
+		if (raw_cpu_has_fpu && !err)
+			break;
+
+		sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 0,
+					       &fault_addr);
+
+		/*
+		 * We can't allow the emulated instruction to leave
+		 * any enabled Cause bits set in $fcr31.
+		 */
+		fcr31 = mask_fcr31_x(current->thread.fpu.fcr31);
+		current->thread.fpu.fcr31 &= ~fcr31;
+
+		/* Send a signal if required.  */
+		if (!process_fpemu_return(sig, fault_addr, fcr31) && !err)
+			mt_ase_fp_affinity();
+
+		break;
+	}
+#else /* CONFIG_MIPS_FP_SUPPORT */
+	case 1:
+	case 3:
+		force_sig(SIGILL);
+		break;
+#endif /* CONFIG_MIPS_FP_SUPPORT */
+
+	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);
+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);
+		goto out;
+	}
+
+	die_if_kernel("do_msa invoked from kernel context!", regs);
+
+	err = enable_restore_fp_context(1);
+	if (err)
+		force_sig(SIGILL);
+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);
+	exception_exit(prev_state);
+}
+
+/*
+ * Called with interrupts disabled.
+ */
+asmlinkage void do_watch(struct pt_regs *regs)
+{
+	enum ctx_state prev_state;
+
+	prev_state = exception_enter();
+	/*
+	 * Clear WP (bit 22) bit of cause register so we don't loop
+	 * forever.
+	 */
+	clear_c0_cause(CAUSEF_WP);
+
+	/*
+	 * 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_fault(SIGTRAP, TRAP_HWBKPT, NULL);
+	} 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;
+
+	prev_state = exception_enter();
+	show_regs(regs);
+
+	if (multi_match) {
+		dump_tlb_regs();
+		pr_info("\n");
+		dump_tlb_all();
+	}
+
+	show_code((void *)regs->cp0_epc, user_mode(regs));
+
+	/*
+	 * 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);
+}
+
+
+asmlinkage void do_dsp(struct pt_regs *regs)
+{
+	if (cpu_has_dsp)
+		panic("Unexpected DSP exception");
+
+	force_sig(SIGILL);
+}
+
+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 __init void parity_protection_init(void)
+{
+#define ERRCTL_PE	0x80000000
+#define ERRCTL_L2P	0x00800000
+
+	if (mips_cm_revision() >= CM_REV_CM3) {
+		ulong gcr_ectl, cp0_ectl;
+
+		/*
+		 * With CM3 systems we need to ensure that the L1 & L2
+		 * parity enables are set to the same value, since this
+		 * is presumed by the hardware engineers.
+		 *
+		 * If the user disabled either of L1 or L2 ECC checking,
+		 * disable both.
+		 */
+		l1parity &= l2parity;
+		l2parity &= l1parity;
+
+		/* Probe L1 ECC support */
+		cp0_ectl = read_c0_ecc();
+		write_c0_ecc(cp0_ectl | ERRCTL_PE);
+		back_to_back_c0_hazard();
+		cp0_ectl = read_c0_ecc();
+
+		/* Probe L2 ECC support */
+		gcr_ectl = read_gcr_err_control();
+
+		if (!(gcr_ectl & CM_GCR_ERR_CONTROL_L2_ECC_SUPPORT) ||
+		    !(cp0_ectl & ERRCTL_PE)) {
+			/*
+			 * One of L1 or L2 ECC checking isn't supported,
+			 * so we cannot enable either.
+			 */
+			l1parity = l2parity = 0;
+		}
+
+		/* Configure L1 ECC checking */
+		if (l1parity)
+			cp0_ectl |= ERRCTL_PE;
+		else
+			cp0_ectl &= ~ERRCTL_PE;
+		write_c0_ecc(cp0_ectl);
+		back_to_back_c0_hazard();
+		WARN_ON(!!(read_c0_ecc() & ERRCTL_PE) != l1parity);
+
+		/* Configure L2 ECC checking */
+		if (l2parity)
+			gcr_ectl |= CM_GCR_ERR_CONTROL_L2_ECC_EN;
+		else
+			gcr_ectl &= ~CM_GCR_ERR_CONTROL_L2_ECC_EN;
+		write_gcr_err_control(gcr_ectl);
+		gcr_ectl = read_gcr_err_control();
+		gcr_ectl &= CM_GCR_ERR_CONTROL_L2_ECC_EN;
+		WARN_ON(!!gcr_ectl != l2parity);
+
+		pr_info("Cache parity protection %sabled\n",
+			l1parity ? "en" : "dis");
+		return;
+	}
+
+	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_P6600:
+		{
+			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_LOONGSON32:
+		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) ||
+	    ((current_cpu_data.processor_id & 0xff0000) == PRID_COMP_LOONGSON))) {
+		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();
+}
+
+asmlinkage void do_gsexc(struct pt_regs *regs, u32 diag1)
+{
+	u32 exccode = (diag1 & LOONGSON_DIAG1_EXCCODE) >>
+			LOONGSON_DIAG1_EXCCODE_SHIFT;
+	enum ctx_state prev_state;
+
+	prev_state = exception_enter();
+
+	switch (exccode) {
+	case 0x08:
+		/* Undocumented exception, will trigger on certain
+		 * also-undocumented instructions accessible from userspace.
+		 * Processor state is not otherwise corrupted, but currently
+		 * we don't know how to proceed. Maybe there is some
+		 * undocumented control flag to enable the instructions?
+		 */
+		force_sig(SIGILL);
+		break;
+
+	default:
+		/* None of the other exceptions, documented or not, have
+		 * further details given; none are encountered in the wild
+		 * either. Panic in case some of them turn out to be fatal.
+		 */
+		show_regs(regs);
+		panic("Unhandled Loongson exception - GSCause = %08x", diag1);
+	}
+
+	exception_exit(prev_state);
+}
+
+/*
+ * 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();
+}
+
+unsigned long ebase;
+EXPORT_SYMBOL_GPL(ebase);
+unsigned long exception_handlers[32];
+unsigned long vi_handlers[64];
+
+void reserve_exception_space(phys_addr_t addr, unsigned long size)
+{
+	memblock_reserve(addr, size);
+}
+
+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 const u8 except_vec_vi[], except_vec_vi_lui[];
+		extern const u8 except_vec_vi_ori[], except_vec_vi_end[];
+		extern const u8 rollback_except_vec_vi[];
+		const u8 *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
+		h[0] = (insn >> 16) & 0xffff;
+		h[1] = insn & 0xffff;
+		h[2] = 0;
+		h[3] = 0;
+		local_flush_icache_range((unsigned long)b,
+					 (unsigned long)(b+8));
+	}
+
+	return (void *)old_handler;
+}
+
+void *set_vi_handler(int n, vi_handler_t addr)
+{
+	return set_vi_srs_handler(n, addr, 0);
+}
+
+extern void tlb_init(void);
+
+/*
+ * Timer interrupt
+ */
+int cp0_compare_irq;
+EXPORT_SYMBOL_GPL(cp0_compare_irq);
+int cp0_compare_irq_shift;
+
+/*
+ * Performance counter IRQ or -1 if shared with timer
+ */
+int cp0_perfcount_irq;
+EXPORT_SYMBOL_GPL(cp0_perfcount_irq);
+
+/*
+ * Fast debug channel IRQ or -1 if not present
+ */
+int cp0_fdc_irq;
+EXPORT_SYMBOL_GPL(cp0_fdc_irq);
+
+static int noulri;
+
+static int __init ulri_disable(char *s)
+{
+	pr_info("Disabling ulri\n");
+	noulri = 1;
+
+	return 1;
+}
+__setup("noulri", ulri_disable);
+
+/* configure STATUS register */
+static void configure_status(void)
+{
+	/*
+	 * Disable coprocessors and select 32-bit or 64-bit addressing
+	 * and the 16/32 or 32/32 FPR register model.  Reset the BEV
+	 * flag that some firmware may have left set and the TS bit (for
+	 * IP27).  Set XX for ISA IV code to work.
+	 */
+	unsigned int status_set = ST0_KERNEL_CUMASK;
+#ifdef CONFIG_64BIT
+	status_set |= ST0_FR|ST0_KX|ST0_SX|ST0_UX;
+#endif
+	if (current_cpu_data.isa_level & MIPS_CPU_ISA_IV)
+		status_set |= ST0_XX;
+	if (cpu_has_dsp)
+		status_set |= ST0_MX;
+
+	change_c0_status(ST0_CU|ST0_MX|ST0_RE|ST0_FR|ST0_BEV|ST0_TS|ST0_KX|ST0_SX|ST0_UX,
+			 status_set);
+	back_to_back_c0_hazard();
+}
+
+unsigned int hwrena;
+EXPORT_SYMBOL_GPL(hwrena);
+
+/* configure HWRENA register */
+static void configure_hwrena(void)
+{
+	hwrena = cpu_hwrena_impl_bits;
+
+	if (cpu_has_mips_r2_r6)
+		hwrena |= MIPS_HWRENA_CPUNUM |
+			  MIPS_HWRENA_SYNCISTEP |
+			  MIPS_HWRENA_CC |
+			  MIPS_HWRENA_CCRES;
+
+	if (!noulri && cpu_has_userlocal)
+		hwrena |= MIPS_HWRENA_ULR;
+
+	if (hwrena)
+		write_c0_hwrena(hwrena);
+}
+
+static void configure_exception_vector(void)
+{
+	if (cpu_has_mips_r2_r6) {
+		unsigned long sr = set_c0_status(ST0_BEV);
+		/* If available, use WG to set top bits of EBASE */
+		if (cpu_has_ebase_wg) {
+#ifdef CONFIG_64BIT
+			write_c0_ebase_64(ebase | MIPS_EBASE_WG);
+#else
+			write_c0_ebase(ebase | MIPS_EBASE_WG);
+#endif
+		}
+		write_c0_ebase(ebase);
+		write_c0_status(sr);
+	}
+	if (cpu_has_veic || cpu_has_vint) {
+		/* Setting vector spacing enables EI/VI mode  */
+		change_c0_intctl(0x3e0, VECTORSPACING);
+	}
+	if (cpu_has_divec) {
+		if (cpu_has_mipsmt) {
+			unsigned int vpflags = dvpe();
+			set_c0_cause(CAUSEF_IV);
+			evpe(vpflags);
+		} else
+			set_c0_cause(CAUSEF_IV);
+	}
+}
+
+void per_cpu_trap_init(bool is_boot_cpu)
+{
+	unsigned int cpu = smp_processor_id();
+
+	configure_status();
+	configure_hwrena();
+
+	configure_exception_vector();
+
+	/*
+	 * Before R2 both interrupt numbers were fixed to 7, so on R2 only:
+	 *
+	 *  o read IntCtl.IPTI to determine the timer interrupt
+	 *  o read IntCtl.IPPCI to determine the performance counter interrupt
+	 *  o read IntCtl.IPFDC to determine the fast debug channel interrupt
+	 */
+	if (cpu_has_mips_r2_r6) {
+		cp0_compare_irq_shift = CAUSEB_TI - CAUSEB_IP;
+		cp0_compare_irq = (read_c0_intctl() >> INTCTLB_IPTI) & 7;
+		cp0_perfcount_irq = (read_c0_intctl() >> INTCTLB_IPPCI) & 7;
+		cp0_fdc_irq = (read_c0_intctl() >> INTCTLB_IPFDC) & 7;
+		if (!cp0_fdc_irq)
+			cp0_fdc_irq = -1;
+
+	} else {
+		cp0_compare_irq = CP0_LEGACY_COMPARE_IRQ;
+		cp0_compare_irq_shift = CP0_LEGACY_PERFCNT_IRQ;
+		cp0_perfcount_irq = -1;
+		cp0_fdc_irq = -1;
+	}
+
+	if (cpu_has_mmid)
+		cpu_data[cpu].asid_cache = 0;
+	else if (!cpu_data[cpu].asid_cache)
+		cpu_data[cpu].asid_cache = asid_first_version(cpu);
+
+	mmgrab(&init_mm);
+	current->active_mm = &init_mm;
+	BUG_ON(current->mm);
+	enter_lazy_tlb(&init_mm, current);
+
+	/* Boot CPU's cache setup in setup_arch(). */
+	if (!is_boot_cpu)
+		cpu_cache_init();
+	tlb_init();
+	TLBMISS_HANDLER_SETUP();
+}
+
+/* Install CPU exception handler */
+void set_handler(unsigned long offset, const void *addr, unsigned long size)
+{
+#ifdef CONFIG_CPU_MICROMIPS
+	memcpy((void *)(ebase + offset), ((unsigned char *)addr - 1), size);
+#else
+	memcpy((void *)(ebase + offset), addr, size);
+#endif
+	local_flush_icache_range(ebase + offset, ebase + offset + size);
+}
+
+static const char panic_null_cerr[] =
+	"Trying to set NULL cache error exception handler\n";
+
+/*
+ * Install uncached CPU exception handler.
+ * This is suitable only for the cache error exception which is the only
+ * exception handler that is being run uncached.
+ */
+void set_uncached_handler(unsigned long offset, void *addr,
+	unsigned long size)
+{
+	unsigned long uncached_ebase = CKSEG1ADDR(ebase);
+
+	if (!addr)
+		panic(panic_null_cerr);
+
+	memcpy((void *)(uncached_ebase + offset), addr, size);
+}
+
+static int __initdata rdhwr_noopt;
+static int __init set_rdhwr_noopt(char *str)
+{
+	rdhwr_noopt = 1;
+	return 1;
+}
+
+__setup("rdhwr_noopt", set_rdhwr_noopt);
+
+void __init trap_init(void)
+{
+	extern char except_vec3_generic;
+	extern char except_vec4;
+	extern char except_vec3_r4000;
+	unsigned long i, vec_size;
+	phys_addr_t ebase_pa;
+
+	check_wait();
+
+	if (!cpu_has_mips_r2_r6) {
+		ebase = CAC_BASE;
+		vec_size = 0x400;
+	} else {
+		if (cpu_has_veic || cpu_has_vint)
+			vec_size = 0x200 + VECTORSPACING*64;
+		else
+			vec_size = PAGE_SIZE;
+
+		ebase_pa = memblock_phys_alloc(vec_size, 1 << fls(vec_size));
+		if (!ebase_pa)
+			panic("%s: Failed to allocate %lu bytes align=0x%x\n",
+			      __func__, vec_size, 1 << fls(vec_size));
+
+		/*
+		 * Try to ensure ebase resides in KSeg0 if possible.
+		 *
+		 * It shouldn't generally be in XKPhys on MIPS64 to avoid
+		 * hitting a poorly defined exception base for Cache Errors.
+		 * The allocation is likely to be in the low 512MB of physical,
+		 * in which case we should be able to convert to KSeg0.
+		 *
+		 * EVA is special though as it allows segments to be rearranged
+		 * and to become uncached during cache error handling.
+		 */
+		if (!IS_ENABLED(CONFIG_EVA) && !WARN_ON(ebase_pa >= 0x20000000))
+			ebase = CKSEG0ADDR(ebase_pa);
+		else
+			ebase = (unsigned long)phys_to_virt(ebase_pa);
+	}
+
+	if (cpu_has_mmips) {
+		unsigned int config3 = read_c0_config3();
+
+		if (IS_ENABLED(CONFIG_CPU_MICROMIPS))
+			write_c0_config3(config3 | MIPS_CONF3_ISA_OE);
+		else
+			write_c0_config3(config3 & ~MIPS_CONF3_ISA_OE);
+	}
+
+	if (board_ebase_setup)
+		board_ebase_setup();
+	per_cpu_trap_init(true);
+	memblock_set_bottom_up(false);
+
+	/*
+	 * Copy the generic exception handlers to their final destination.
+	 * This will be overridden later as suitable for a particular
+	 * configuration.
+	 */
+	set_handler(0x180, &except_vec3_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 && board_ejtag_handler_setup)
+		board_ejtag_handler_setup();
+
+	/*
+	 * Only some CPUs have the watch exceptions.
+	 */
+	if (cpu_has_watch)
+		set_except_vector(EXCCODE_WATCH, handle_watch);
+
+	/*
+	 * Initialise interrupt handlers
+	 */
+	if (cpu_has_veic || cpu_has_vint) {
+		int nvec = cpu_has_veic ? 64 : 8;
+		for (i = 0; i < nvec; i++)
+			set_vi_handler(i, NULL);
+	}
+	else if (cpu_has_divec)
+		set_handler(0x200, &except_vec4, 0x8);
+
+	/*
+	 * 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(EXCCODE_INT, using_rollback_handler() ?
+					rollback_handle_int : handle_int);
+	set_except_vector(EXCCODE_MOD, handle_tlbm);
+	set_except_vector(EXCCODE_TLBL, handle_tlbl);
+	set_except_vector(EXCCODE_TLBS, handle_tlbs);
+
+	set_except_vector(EXCCODE_ADEL, handle_adel);
+	set_except_vector(EXCCODE_ADES, handle_ades);
+
+	set_except_vector(EXCCODE_IBE, handle_ibe);
+	set_except_vector(EXCCODE_DBE, handle_dbe);
+
+	set_except_vector(EXCCODE_SYS, handle_sys);
+	set_except_vector(EXCCODE_BP, handle_bp);
+
+	if (rdhwr_noopt)
+		set_except_vector(EXCCODE_RI, handle_ri);
+	else {
+		if (cpu_has_vtag_icache)
+			set_except_vector(EXCCODE_RI, handle_ri_rdhwr_tlbp);
+		else if (current_cpu_type() == CPU_LOONGSON64)
+			set_except_vector(EXCCODE_RI, handle_ri_rdhwr_tlbp);
+		else
+			set_except_vector(EXCCODE_RI, handle_ri_rdhwr);
+	}
+
+	set_except_vector(EXCCODE_CPU, handle_cpu);
+	set_except_vector(EXCCODE_OV, handle_ov);
+	set_except_vector(EXCCODE_TR, handle_tr);
+	set_except_vector(EXCCODE_MSAFPE, handle_msa_fpe);
+
+	if (board_nmi_handler_setup)
+		board_nmi_handler_setup();
+
+	if (cpu_has_fpu && !cpu_has_nofpuex)
+		set_except_vector(EXCCODE_FPE, handle_fpe);
+
+	if (cpu_has_ftlbparex)
+		set_except_vector(MIPS_EXCCODE_TLBPAR, handle_ftlb);
+
+	if (cpu_has_gsexcex)
+		set_except_vector(LOONGSON_EXCCODE_GSEXC, handle_gsexc);
+
+	if (cpu_has_rixiex) {
+		set_except_vector(EXCCODE_TLBRI, tlb_do_page_fault_0);
+		set_except_vector(EXCCODE_TLBXI, tlb_do_page_fault_0);
+	}
+
+	set_except_vector(EXCCODE_MSADIS, handle_msa);
+	set_except_vector(EXCCODE_MDMX, handle_mdmx);
+
+	if (cpu_has_mcheck)
+		set_except_vector(EXCCODE_MCHECK, handle_mcheck);
+
+	if (cpu_has_mipsmt)
+		set_except_vector(EXCCODE_THREAD, handle_mt);
+
+	set_except_vector(EXCCODE_DSPDIS, handle_dsp);
+
+	if (board_cache_error_setup)
+		board_cache_error_setup();
+
+	if (cpu_has_vce)
+		/* Special exception: R4[04]00 uses also the divec space. */
+		set_handler(0x180, &except_vec3_r4000, 0x100);
+	else if (cpu_has_4kex)
+		set_handler(0x180, &except_vec3_generic, 0x80);
+	else
+		set_handler(0x080, &except_vec3_generic, 0x80);
+
+	local_flush_icache_range(ebase, ebase + vec_size);
+
+	sort_extable(__start___dbe_table, __stop___dbe_table);
+
+	cu2_notifier(default_cu2_call, 0x80000000);	/* Run last  */
+}
+
+static int trap_pm_notifier(struct notifier_block *self, unsigned long cmd,
+			    void *v)
+{
+	switch (cmd) {
+	case CPU_PM_ENTER_FAILED:
+	case CPU_PM_EXIT:
+		configure_status();
+		configure_hwrena();
+		configure_exception_vector();
+
+		/* Restore register with CPU number for TLB handlers */
+		TLBMISS_HANDLER_RESTORE();
+
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block trap_pm_notifier_block = {
+	.notifier_call = trap_pm_notifier,
+};
+
+static int __init trap_pm_init(void)
+{
+	return cpu_pm_register_notifier(&trap_pm_notifier_block);
+}
+arch_initcall(trap_pm_init);