sh: Move in the SH-5 traps.c impl.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 947 insertions, 0 deletions

diff --git a/arch/sh/kernel/traps_32.c b/arch/sh/kernel/traps_32.c
new file mode 100644
index 00000000000..cf99111cb33
--- /dev/null
+++ b/arch/sh/kernel/traps_32.c
@@ -0,0 +1,947 @@
+/*
+ * 'traps.c' handles hardware traps and faults after we have saved some
+ * state in 'entry.S'.
+ *
+ *  SuperH version: Copyright (C) 1999 Niibe Yutaka
+ *                  Copyright (C) 2000 Philipp Rumpf
+ *                  Copyright (C) 2000 David Howells
+ *                  Copyright (C) 2002 - 2007 Paul Mundt
+ *
+ * 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.
+ */
+#include <linux/kernel.h>
+#include <linux/ptrace.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/io.h>
+#include <linux/bug.h>
+#include <linux/debug_locks.h>
+#include <linux/kdebug.h>
+#include <linux/kexec.h>
+#include <linux/limits.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+
+#ifdef CONFIG_SH_KGDB
+#include <asm/kgdb.h>
+#define CHK_REMOTE_DEBUG(regs)			\
+{						\
+	if (kgdb_debug_hook && !user_mode(regs))\
+		(*kgdb_debug_hook)(regs);       \
+}
+#else
+#define CHK_REMOTE_DEBUG(regs)
+#endif
+
+#ifdef CONFIG_CPU_SH2
+# define TRAP_RESERVED_INST	4
+# define TRAP_ILLEGAL_SLOT_INST	6
+# define TRAP_ADDRESS_ERROR	9
+# ifdef CONFIG_CPU_SH2A
+#  define TRAP_DIVZERO_ERROR	17
+#  define TRAP_DIVOVF_ERROR	18
+# endif
+#else
+#define TRAP_RESERVED_INST	12
+#define TRAP_ILLEGAL_SLOT_INST	13
+#endif
+
+static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
+{
+	unsigned long p;
+	int i;
+
+	printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
+
+	for (p = bottom & ~31; p < top; ) {
+		printk("%04lx: ", p & 0xffff);
+
+		for (i = 0; i < 8; i++, p += 4) {
+			unsigned int val;
+
+			if (p < bottom || p >= top)
+				printk("         ");
+			else {
+				if (__get_user(val, (unsigned int __user *)p)) {
+					printk("\n");
+					return;
+				}
+				printk("%08x ", val);
+			}
+		}
+		printk("\n");
+	}
+}
+
+static DEFINE_SPINLOCK(die_lock);
+
+void die(const char * str, struct pt_regs * regs, long err)
+{
+	static int die_counter;
+
+	oops_enter();
+
+	console_verbose();
+	spin_lock_irq(&die_lock);
+	bust_spinlocks(1);
+
+	printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
+
+	CHK_REMOTE_DEBUG(regs);
+	print_modules();
+	show_regs(regs);
+
+	printk("Process: %s (pid: %d, stack limit = %p)\n", current->comm,
+			task_pid_nr(current), task_stack_page(current) + 1);
+
+	if (!user_mode(regs) || in_interrupt())
+		dump_mem("Stack: ", regs->regs[15], THREAD_SIZE +
+			 (unsigned long)task_stack_page(current));
+
+	bust_spinlocks(0);
+	add_taint(TAINT_DIE);
+	spin_unlock_irq(&die_lock);
+
+	if (kexec_should_crash(current))
+		crash_kexec(regs);
+
+	if (in_interrupt())
+		panic("Fatal exception in interrupt");
+
+	if (panic_on_oops)
+		panic("Fatal exception");
+
+	oops_exit();
+	do_exit(SIGSEGV);
+}
+
+static inline void die_if_kernel(const char *str, struct pt_regs *regs,
+				 long err)
+{
+	if (!user_mode(regs))
+		die(str, regs, err);
+}
+
+/*
+ * try and fix up kernelspace address errors
+ * - userspace errors just cause EFAULT to be returned, resulting in SEGV
+ * - kernel/userspace interfaces cause a jump to an appropriate handler
+ * - other kernel errors are bad
+ * - return 0 if fixed-up, -EFAULT if non-fatal (to the kernel) fault
+ */
+static int die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
+{
+	if (!user_mode(regs)) {
+		const struct exception_table_entry *fixup;
+		fixup = search_exception_tables(regs->pc);
+		if (fixup) {
+			regs->pc = fixup->fixup;
+			return 0;
+		}
+		die(str, regs, err);
+	}
+	return -EFAULT;
+}
+
+/*
+ * handle an instruction that does an unaligned memory access by emulating the
+ * desired behaviour
+ * - note that PC _may not_ point to the faulting instruction
+ *   (if that instruction is in a branch delay slot)
+ * - return 0 if emulation okay, -EFAULT on existential error
+ */
+static int handle_unaligned_ins(u16 instruction, struct pt_regs *regs)
+{
+	int ret, index, count;
+	unsigned long *rm, *rn;
+	unsigned char *src, *dst;
+
+	index = (instruction>>8)&15;	/* 0x0F00 */
+	rn = &regs->regs[index];
+
+	index = (instruction>>4)&15;	/* 0x00F0 */
+	rm = &regs->regs[index];
+
+	count = 1<<(instruction&3);
+
+	ret = -EFAULT;
+	switch (instruction>>12) {
+	case 0: /* mov.[bwl] to/from memory via r0+rn */
+		if (instruction & 8) {
+			/* from memory */
+			src = (unsigned char*) *rm;
+			src += regs->regs[0];
+			dst = (unsigned char*) rn;
+			*(unsigned long*)dst = 0;
+
+#ifdef __LITTLE_ENDIAN__
+			if (copy_from_user(dst, src, count))
+				goto fetch_fault;
+
+			if ((count == 2) && dst[1] & 0x80) {
+				dst[2] = 0xff;
+				dst[3] = 0xff;
+			}
+#else
+			dst += 4-count;
+
+			if (__copy_user(dst, src, count))
+				goto fetch_fault;
+
+			if ((count == 2) && dst[2] & 0x80) {
+				dst[0] = 0xff;
+				dst[1] = 0xff;
+			}
+#endif
+		} else {
+			/* to memory */
+			src = (unsigned char*) rm;
+#if !defined(__LITTLE_ENDIAN__)
+			src += 4-count;
+#endif
+			dst = (unsigned char*) *rn;
+			dst += regs->regs[0];
+
+			if (copy_to_user(dst, src, count))
+				goto fetch_fault;
+		}
+		ret = 0;
+		break;
+
+	case 1: /* mov.l Rm,@(disp,Rn) */
+		src = (unsigned char*) rm;
+		dst = (unsigned char*) *rn;
+		dst += (instruction&0x000F)<<2;
+
+		if (copy_to_user(dst,src,4))
+			goto fetch_fault;
+		ret = 0;
+		break;
+
+	case 2: /* mov.[bwl] to memory, possibly with pre-decrement */
+		if (instruction & 4)
+			*rn -= count;
+		src = (unsigned char*) rm;
+		dst = (unsigned char*) *rn;
+#if !defined(__LITTLE_ENDIAN__)
+		src += 4-count;
+#endif
+		if (copy_to_user(dst, src, count))
+			goto fetch_fault;
+		ret = 0;
+		break;
+
+	case 5: /* mov.l @(disp,Rm),Rn */
+		src = (unsigned char*) *rm;
+		src += (instruction&0x000F)<<2;
+		dst = (unsigned char*) rn;
+		*(unsigned long*)dst = 0;
+
+		if (copy_from_user(dst,src,4))
+			goto fetch_fault;
+		ret = 0;
+		break;
+
+	case 6:	/* mov.[bwl] from memory, possibly with post-increment */
+		src = (unsigned char*) *rm;
+		if (instruction & 4)
+			*rm += count;
+		dst = (unsigned char*) rn;
+		*(unsigned long*)dst = 0;
+
+#ifdef __LITTLE_ENDIAN__
+		if (copy_from_user(dst, src, count))
+			goto fetch_fault;
+
+		if ((count == 2) && dst[1] & 0x80) {
+			dst[2] = 0xff;
+			dst[3] = 0xff;
+		}
+#else
+		dst += 4-count;
+
+		if (copy_from_user(dst, src, count))
+			goto fetch_fault;
+
+		if ((count == 2) && dst[2] & 0x80) {
+			dst[0] = 0xff;
+			dst[1] = 0xff;
+		}
+#endif
+		ret = 0;
+		break;
+
+	case 8:
+		switch ((instruction&0xFF00)>>8) {
+		case 0x81: /* mov.w R0,@(disp,Rn) */
+			src = (unsigned char*) &regs->regs[0];
+#if !defined(__LITTLE_ENDIAN__)
+			src += 2;
+#endif
+			dst = (unsigned char*) *rm; /* called Rn in the spec */
+			dst += (instruction&0x000F)<<1;
+
+			if (copy_to_user(dst, src, 2))
+				goto fetch_fault;
+			ret = 0;
+			break;
+
+		case 0x85: /* mov.w @(disp,Rm),R0 */
+			src = (unsigned char*) *rm;
+			src += (instruction&0x000F)<<1;
+			dst = (unsigned char*) &regs->regs[0];
+			*(unsigned long*)dst = 0;
+
+#if !defined(__LITTLE_ENDIAN__)
+			dst += 2;
+#endif
+
+			if (copy_from_user(dst, src, 2))
+				goto fetch_fault;
+
+#ifdef __LITTLE_ENDIAN__
+			if (dst[1] & 0x80) {
+				dst[2] = 0xff;
+				dst[3] = 0xff;
+			}
+#else
+			if (dst[2] & 0x80) {
+				dst[0] = 0xff;
+				dst[1] = 0xff;
+			}
+#endif
+			ret = 0;
+			break;
+		}
+		break;
+	}
+	return ret;
+
+ fetch_fault:
+	/* Argh. Address not only misaligned but also non-existent.
+	 * Raise an EFAULT and see if it's trapped
+	 */
+	return die_if_no_fixup("Fault in unaligned fixup", regs, 0);
+}
+
+/*
+ * emulate the instruction in the delay slot
+ * - fetches the instruction from PC+2
+ */
+static inline int handle_unaligned_delayslot(struct pt_regs *regs)
+{
+	u16 instruction;
+
+	if (copy_from_user(&instruction, (u16 *)(regs->pc+2), 2)) {
+		/* the instruction-fetch faulted */
+		if (user_mode(regs))
+			return -EFAULT;
+
+		/* kernel */
+		die("delay-slot-insn faulting in handle_unaligned_delayslot",
+		    regs, 0);
+	}
+
+	return handle_unaligned_ins(instruction,regs);
+}
+
+/*
+ * handle an instruction that does an unaligned memory access
+ * - have to be careful of branch delay-slot instructions that fault
+ *  SH3:
+ *   - if the branch would be taken PC points to the branch
+ *   - if the branch would not be taken, PC points to delay-slot
+ *  SH4:
+ *   - PC always points to delayed branch
+ * - return 0 if handled, -EFAULT if failed (may not return if in kernel)
+ */
+
+/* Macros to determine offset from current PC for branch instructions */
+/* Explicit type coercion is used to force sign extension where needed */
+#define SH_PC_8BIT_OFFSET(instr) ((((signed char)(instr))*2) + 4)
+#define SH_PC_12BIT_OFFSET(instr) ((((signed short)(instr<<4))>>3) + 4)
+
+/*
+ * XXX: SH-2A needs this too, but it needs an overhaul thanks to mixed 32-bit
+ * opcodes..
+ */
+#ifndef CONFIG_CPU_SH2A
+static int handle_unaligned_notify_count = 10;
+
+static int handle_unaligned_access(u16 instruction, struct pt_regs *regs)
+{
+	u_int rm;
+	int ret, index;
+
+	index = (instruction>>8)&15;	/* 0x0F00 */
+	rm = regs->regs[index];
+
+	/* shout about the first ten userspace fixups */
+	if (user_mode(regs) && handle_unaligned_notify_count>0) {
+		handle_unaligned_notify_count--;
+
+		printk(KERN_NOTICE "Fixing up unaligned userspace access "
+		       "in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n",
+		       current->comm, task_pid_nr(current),
+		       (u16 *)regs->pc, instruction);
+	}
+
+	ret = -EFAULT;
+	switch (instruction&0xF000) {
+	case 0x0000:
+		if (instruction==0x000B) {
+			/* rts */
+			ret = handle_unaligned_delayslot(regs);
+			if (ret==0)
+				regs->pc = regs->pr;
+		}
+		else if ((instruction&0x00FF)==0x0023) {
+			/* braf @Rm */
+			ret = handle_unaligned_delayslot(regs);
+			if (ret==0)
+				regs->pc += rm + 4;
+		}
+		else if ((instruction&0x00FF)==0x0003) {
+			/* bsrf @Rm */
+			ret = handle_unaligned_delayslot(regs);
+			if (ret==0) {
+				regs->pr = regs->pc + 4;
+				regs->pc += rm + 4;
+			}
+		}
+		else {
+			/* mov.[bwl] to/from memory via r0+rn */
+			goto simple;
+		}
+		break;
+
+	case 0x1000: /* mov.l Rm,@(disp,Rn) */
+		goto simple;
+
+	case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */
+		goto simple;
+
+	case 0x4000:
+		if ((instruction&0x00FF)==0x002B) {
+			/* jmp @Rm */
+			ret = handle_unaligned_delayslot(regs);
+			if (ret==0)
+				regs->pc = rm;
+		}
+		else if ((instruction&0x00FF)==0x000B) {
+			/* jsr @Rm */
+			ret = handle_unaligned_delayslot(regs);
+			if (ret==0) {
+				regs->pr = regs->pc + 4;
+				regs->pc = rm;
+			}
+		}
+		else {
+			/* mov.[bwl] to/from memory via r0+rn */
+			goto simple;
+		}
+		break;
+
+	case 0x5000: /* mov.l @(disp,Rm),Rn */
+		goto simple;
+
+	case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */
+		goto simple;
+
+	case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */
+		switch (instruction&0x0F00) {
+		case 0x0100: /* mov.w R0,@(disp,Rm) */
+			goto simple;
+		case 0x0500: /* mov.w @(disp,Rm),R0 */
+			goto simple;
+		case 0x0B00: /* bf   lab - no delayslot*/
+			break;
+		case 0x0F00: /* bf/s lab */
+			ret = handle_unaligned_delayslot(regs);
+			if (ret==0) {
+#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
+				if ((regs->sr & 0x00000001) != 0)
+					regs->pc += 4; /* next after slot */
+				else
+#endif
+					regs->pc += SH_PC_8BIT_OFFSET(instruction);
+			}
+			break;
+		case 0x0900: /* bt   lab - no delayslot */
+			break;
+		case 0x0D00: /* bt/s lab */
+			ret = handle_unaligned_delayslot(regs);
+			if (ret==0) {
+#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
+				if ((regs->sr & 0x00000001) == 0)
+					regs->pc += 4; /* next after slot */
+				else
+#endif
+					regs->pc += SH_PC_8BIT_OFFSET(instruction);
+			}
+			break;
+		}
+		break;
+
+	case 0xA000: /* bra label */
+		ret = handle_unaligned_delayslot(regs);
+		if (ret==0)
+			regs->pc += SH_PC_12BIT_OFFSET(instruction);
+		break;
+
+	case 0xB000: /* bsr label */
+		ret = handle_unaligned_delayslot(regs);
+		if (ret==0) {
+			regs->pr = regs->pc + 4;
+			regs->pc += SH_PC_12BIT_OFFSET(instruction);
+		}
+		break;
+	}
+	return ret;
+
+	/* handle non-delay-slot instruction */
+ simple:
+	ret = handle_unaligned_ins(instruction,regs);
+	if (ret==0)
+		regs->pc += instruction_size(instruction);
+	return ret;
+}
+#endif /* CONFIG_CPU_SH2A */
+
+#ifdef CONFIG_CPU_HAS_SR_RB
+#define lookup_exception_vector(x)	\
+	__asm__ __volatile__ ("stc r2_bank, %0\n\t" : "=r" ((x)))
+#else
+#define lookup_exception_vector(x)	\
+	__asm__ __volatile__ ("mov r4, %0\n\t" : "=r" ((x)))
+#endif
+
+/*
+ * Handle various address error exceptions:
+ *  - instruction address error:
+ *       misaligned PC
+ *       PC >= 0x80000000 in user mode
+ *  - data address error (read and write)
+ *       misaligned data access
+ *       access to >= 0x80000000 is user mode
+ * Unfortuntaly we can't distinguish between instruction address error
+ * and data address errors caused by read accesses.
+ */
+asmlinkage void do_address_error(struct pt_regs *regs,
+				 unsigned long writeaccess,
+				 unsigned long address)
+{
+	unsigned long error_code = 0;
+	mm_segment_t oldfs;
+	siginfo_t info;
+#ifndef CONFIG_CPU_SH2A
+	u16 instruction;
+	int tmp;
+#endif
+
+	/* Intentional ifdef */
+#ifdef CONFIG_CPU_HAS_SR_RB
+	lookup_exception_vector(error_code);
+#endif
+
+	oldfs = get_fs();
+
+	if (user_mode(regs)) {
+		int si_code = BUS_ADRERR;
+
+		local_irq_enable();
+
+		/* bad PC is not something we can fix */
+		if (regs->pc & 1) {
+			si_code = BUS_ADRALN;
+			goto uspace_segv;
+		}
+
+#ifndef CONFIG_CPU_SH2A
+		set_fs(USER_DS);
+		if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) {
+			/* Argh. Fault on the instruction itself.
+			   This should never happen non-SMP
+			*/
+			set_fs(oldfs);
+			goto uspace_segv;
+		}
+
+		tmp = handle_unaligned_access(instruction, regs);
+		set_fs(oldfs);
+
+		if (tmp==0)
+			return; /* sorted */
+#endif
+
+uspace_segv:
+		printk(KERN_NOTICE "Sending SIGBUS to \"%s\" due to unaligned "
+		       "access (PC %lx PR %lx)\n", current->comm, regs->pc,
+		       regs->pr);
+
+		info.si_signo = SIGBUS;
+		info.si_errno = 0;
+		info.si_code = si_code;
+		info.si_addr = (void __user *)address;
+		force_sig_info(SIGBUS, &info, current);
+	} else {
+		if (regs->pc & 1)
+			die("unaligned program counter", regs, error_code);
+
+#ifndef CONFIG_CPU_SH2A
+		set_fs(KERNEL_DS);
+		if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) {
+			/* Argh. Fault on the instruction itself.
+			   This should never happen non-SMP
+			*/
+			set_fs(oldfs);
+			die("insn faulting in do_address_error", regs, 0);
+		}
+
+		handle_unaligned_access(instruction, regs);
+		set_fs(oldfs);
+#else
+		printk(KERN_NOTICE "Killing process \"%s\" due to unaligned "
+		       "access\n", current->comm);
+
+		force_sig(SIGSEGV, current);
+#endif
+	}
+}
+
+#ifdef CONFIG_SH_DSP
+/*
+ *	SH-DSP support gerg@snapgear.com.
+ */
+int is_dsp_inst(struct pt_regs *regs)
+{
+	unsigned short inst = 0;
+
+	/*
+	 * Safe guard if DSP mode is already enabled or we're lacking
+	 * the DSP altogether.
+	 */
+	if (!(current_cpu_data.flags & CPU_HAS_DSP) || (regs->sr & SR_DSP))
+		return 0;
+
+	get_user(inst, ((unsigned short *) regs->pc));
+
+	inst &= 0xf000;
+
+	/* Check for any type of DSP or support instruction */
+	if ((inst == 0xf000) || (inst == 0x4000))
+		return 1;
+
+	return 0;
+}
+#else
+#define is_dsp_inst(regs)	(0)
+#endif /* CONFIG_SH_DSP */
+
+#ifdef CONFIG_CPU_SH2A
+asmlinkage void do_divide_error(unsigned long r4, unsigned long r5,
+				unsigned long r6, unsigned long r7,
+				struct pt_regs __regs)
+{
+	siginfo_t info;
+
+	switch (r4) {
+	case TRAP_DIVZERO_ERROR:
+		info.si_code = FPE_INTDIV;
+		break;
+	case TRAP_DIVOVF_ERROR:
+		info.si_code = FPE_INTOVF;
+		break;
+	}
+
+	force_sig_info(SIGFPE, &info, current);
+}
+#endif
+
+/* arch/sh/kernel/cpu/sh4/fpu.c */
+extern int do_fpu_inst(unsigned short, struct pt_regs *);
+extern asmlinkage void do_fpu_state_restore(unsigned long r4, unsigned long r5,
+		unsigned long r6, unsigned long r7, struct pt_regs __regs);
+
+asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
+				unsigned long r6, unsigned long r7,
+				struct pt_regs __regs)
+{
+	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
+	unsigned long error_code;
+	struct task_struct *tsk = current;
+
+#ifdef CONFIG_SH_FPU_EMU
+	unsigned short inst = 0;
+	int err;
+
+	get_user(inst, (unsigned short*)regs->pc);
+
+	err = do_fpu_inst(inst, regs);
+	if (!err) {
+		regs->pc += instruction_size(inst);
+		return;
+	}
+	/* not a FPU inst. */
+#endif
+
+#ifdef CONFIG_SH_DSP
+	/* Check if it's a DSP instruction */
+	if (is_dsp_inst(regs)) {
+		/* Enable DSP mode, and restart instruction. */
+		regs->sr |= SR_DSP;
+		return;
+	}
+#endif
+
+	lookup_exception_vector(error_code);
+
+	local_irq_enable();
+	CHK_REMOTE_DEBUG(regs);
+	force_sig(SIGILL, tsk);
+	die_if_no_fixup("reserved instruction", regs, error_code);
+}
+
+#ifdef CONFIG_SH_FPU_EMU
+static int emulate_branch(unsigned short inst, struct pt_regs* regs)
+{
+	/*
+	 * bfs: 8fxx: PC+=d*2+4;
+	 * bts: 8dxx: PC+=d*2+4;
+	 * bra: axxx: PC+=D*2+4;
+	 * bsr: bxxx: PC+=D*2+4  after PR=PC+4;
+	 * braf:0x23: PC+=Rn*2+4;
+	 * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4;
+	 * jmp: 4x2b: PC=Rn;
+	 * jsr: 4x0b: PC=Rn      after PR=PC+4;
+	 * rts: 000b: PC=PR;
+	 */
+	if ((inst & 0xfd00) == 0x8d00) {
+		regs->pc += SH_PC_8BIT_OFFSET(inst);
+		return 0;
+	}
+
+	if ((inst & 0xe000) == 0xa000) {
+		regs->pc += SH_PC_12BIT_OFFSET(inst);
+		return 0;
+	}
+
+	if ((inst & 0xf0df) == 0x0003) {
+		regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
+		return 0;
+	}
+
+	if ((inst & 0xf0df) == 0x400b) {
+		regs->pc = regs->regs[(inst & 0x0f00) >> 8];
+		return 0;
+	}
+
+	if ((inst & 0xffff) == 0x000b) {
+		regs->pc = regs->pr;
+		return 0;
+	}
+
+	return 1;
+}
+#endif
+
+asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5,
+				unsigned long r6, unsigned long r7,
+				struct pt_regs __regs)
+{
+	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
+	unsigned long error_code;
+	struct task_struct *tsk = current;
+#ifdef CONFIG_SH_FPU_EMU
+	unsigned short inst = 0;
+
+	get_user(inst, (unsigned short *)regs->pc + 1);
+	if (!do_fpu_inst(inst, regs)) {
+		get_user(inst, (unsigned short *)regs->pc);
+		if (!emulate_branch(inst, regs))
+			return;
+		/* fault in branch.*/
+	}
+	/* not a FPU inst. */
+#endif
+
+	lookup_exception_vector(error_code);
+
+	local_irq_enable();
+	CHK_REMOTE_DEBUG(regs);
+	force_sig(SIGILL, tsk);
+	die_if_no_fixup("illegal slot instruction", regs, error_code);
+}
+
+asmlinkage void do_exception_error(unsigned long r4, unsigned long r5,
+				   unsigned long r6, unsigned long r7,
+				   struct pt_regs __regs)
+{
+	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
+	long ex;
+
+	lookup_exception_vector(ex);
+	die_if_kernel("exception", regs, ex);
+}
+
+#if defined(CONFIG_SH_STANDARD_BIOS)
+void *gdb_vbr_vector;
+
+static inline void __init gdb_vbr_init(void)
+{
+	register unsigned long vbr;
+
+	/*
+	 * Read the old value of the VBR register to initialise
+	 * the vector through which debug and BIOS traps are
+	 * delegated by the Linux trap handler.
+	 */
+	asm volatile("stc vbr, %0" : "=r" (vbr));
+
+	gdb_vbr_vector = (void *)(vbr + 0x100);
+	printk("Setting GDB trap vector to 0x%08lx\n",
+	       (unsigned long)gdb_vbr_vector);
+}
+#endif
+
+void __cpuinit per_cpu_trap_init(void)
+{
+	extern void *vbr_base;
+
+#ifdef CONFIG_SH_STANDARD_BIOS
+	if (raw_smp_processor_id() == 0)
+		gdb_vbr_init();
+#endif
+
+	/* NOTE: The VBR value should be at P1
+	   (or P2, virtural "fixed" address space).
+	   It's definitely should not in physical address.  */
+
+	asm volatile("ldc	%0, vbr"
+		     : /* no output */
+		     : "r" (&vbr_base)
+		     : "memory");
+}
+
+void *set_exception_table_vec(unsigned int vec, void *handler)
+{
+	extern void *exception_handling_table[];
+	void *old_handler;
+
+	old_handler = exception_handling_table[vec];
+	exception_handling_table[vec] = handler;
+	return old_handler;
+}
+
+extern asmlinkage void address_error_handler(unsigned long r4, unsigned long r5,
+					     unsigned long r6, unsigned long r7,
+					     struct pt_regs __regs);
+
+void __init trap_init(void)
+{
+	set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst);
+	set_exception_table_vec(TRAP_ILLEGAL_SLOT_INST, do_illegal_slot_inst);
+
+#if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \
+    defined(CONFIG_SH_FPU_EMU)
+	/*
+	 * For SH-4 lacking an FPU, treat floating point instructions as
+	 * reserved. They'll be handled in the math-emu case, or faulted on
+	 * otherwise.
+	 */
+	set_exception_table_evt(0x800, do_reserved_inst);
+	set_exception_table_evt(0x820, do_illegal_slot_inst);
+#elif defined(CONFIG_SH_FPU)
+#ifdef CONFIG_CPU_SUBTYPE_SHX3
+	set_exception_table_evt(0xd80, do_fpu_state_restore);
+	set_exception_table_evt(0xda0, do_fpu_state_restore);
+#else
+	set_exception_table_evt(0x800, do_fpu_state_restore);
+	set_exception_table_evt(0x820, do_fpu_state_restore);
+#endif
+#endif
+
+#ifdef CONFIG_CPU_SH2
+	set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_handler);
+#endif
+#ifdef CONFIG_CPU_SH2A
+	set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error);
+	set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error);
+#endif
+
+	/* Setup VBR for boot cpu */
+	per_cpu_trap_init();
+}
+
+#ifdef CONFIG_BUG
+void handle_BUG(struct pt_regs *regs)
+{
+	enum bug_trap_type tt;
+	tt = report_bug(regs->pc, regs);
+	if (tt == BUG_TRAP_TYPE_WARN) {
+		regs->pc += 2;
+		return;
+	}
+
+	die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff);
+}
+
+int is_valid_bugaddr(unsigned long addr)
+{
+	return addr >= PAGE_OFFSET;
+}
+#endif
+
+void show_trace(struct task_struct *tsk, unsigned long *sp,
+		struct pt_regs *regs)
+{
+	unsigned long addr;
+
+	if (regs && user_mode(regs))
+		return;
+
+	printk("\nCall trace: ");
+#ifdef CONFIG_KALLSYMS
+	printk("\n");
+#endif
+
+	while (!kstack_end(sp)) {
+		addr = *sp++;
+		if (kernel_text_address(addr))
+			print_ip_sym(addr);
+	}
+
+	printk("\n");
+
+	if (!tsk)
+		tsk = current;
+
+	debug_show_held_locks(tsk);
+}
+
+void show_stack(struct task_struct *tsk, unsigned long *sp)
+{
+	unsigned long stack;
+
+	if (!tsk)
+		tsk = current;
+	if (tsk == current)
+		sp = (unsigned long *)current_stack_pointer;
+	else
+		sp = (unsigned long *)tsk->thread.sp;
+
+	stack = (unsigned long)sp;
+	dump_mem("Stack: ", stack, THREAD_SIZE +
+		 (unsigned long)task_stack_page(tsk));
+	show_trace(tsk, sp, NULL);
+}
+
+void dump_stack(void)
+{
+	show_stack(NULL, NULL);
+}
+EXPORT_SYMBOL(dump_stack);