Initial import

1 files changed, 795 insertions, 0 deletions

diff --git a/arch/sh/kernel/traps_32.c b/arch/sh/kernel/traps_32.c
new file mode 100644
index 000000000..ff639342a
--- /dev/null
+++ b/arch/sh/kernel/traps_32.c
@@ -0,0 +1,795 @@
+/*
+ * '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 - 2010 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/hardirq.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/kallsyms.h>
+#include <linux/io.h>
+#include <linux/bug.h>
+#include <linux/debug_locks.h>
+#include <linux/kdebug.h>
+#include <linux/limits.h>
+#include <linux/sysfs.h>
+#include <linux/uaccess.h>
+#include <linux/perf_event.h>
+#include <asm/alignment.h>
+#include <asm/fpu.h>
+#include <asm/kprobes.h>
+#include <asm/traps.h>
+#include <asm/bl_bit.h>
+
+#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_UBC		12
+#  define TRAP_FPU_ERROR	13
+#  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 inline void sign_extend(unsigned int count, unsigned char *dst)
+{
+#ifdef __LITTLE_ENDIAN__
+	if ((count == 1) && dst[0] & 0x80) {
+		dst[1] = 0xff;
+		dst[2] = 0xff;
+		dst[3] = 0xff;
+	}
+	if ((count == 2) && dst[1] & 0x80) {
+		dst[2] = 0xff;
+		dst[3] = 0xff;
+	}
+#else
+	if ((count == 1) && dst[3] & 0x80) {
+		dst[2] = 0xff;
+		dst[1] = 0xff;
+		dst[0] = 0xff;
+	}
+	if ((count == 2) && dst[2] & 0x80) {
+		dst[1] = 0xff;
+		dst[0] = 0xff;
+	}
+#endif
+}
+
+static struct mem_access user_mem_access = {
+	copy_from_user,
+	copy_to_user,
+};
+
+/*
+ * 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(insn_size_t instruction, struct pt_regs *regs,
+				struct mem_access *ma)
+{
+	int ret, index, count;
+	unsigned long *rm, *rn;
+	unsigned char *src, *dst;
+	unsigned char __user *srcu, *dstu;
+
+	index = (instruction>>8)&15;	/* 0x0F00 */
+	rn = &regs->regs[index];
+
+	index = (instruction>>4)&15;	/* 0x00F0 */
+	rm = &regs->regs[index];
+
+	count = 1<<(instruction&3);
+
+	switch (count) {
+	case 1: inc_unaligned_byte_access(); break;
+	case 2: inc_unaligned_word_access(); break;
+	case 4: inc_unaligned_dword_access(); break;
+	case 8: inc_unaligned_multi_access(); break;
+	}
+
+	ret = -EFAULT;
+	switch (instruction>>12) {
+	case 0: /* mov.[bwl] to/from memory via r0+rn */
+		if (instruction & 8) {
+			/* from memory */
+			srcu = (unsigned char __user *)*rm;
+			srcu += regs->regs[0];
+			dst = (unsigned char *)rn;
+			*(unsigned long *)dst = 0;
+
+#if !defined(__LITTLE_ENDIAN__)
+			dst += 4-count;
+#endif
+			if (ma->from(dst, srcu, count))
+				goto fetch_fault;
+
+			sign_extend(count, dst);
+		} else {
+			/* to memory */
+			src = (unsigned char *)rm;
+#if !defined(__LITTLE_ENDIAN__)
+			src += 4-count;
+#endif
+			dstu = (unsigned char __user *)*rn;
+			dstu += regs->regs[0];
+
+			if (ma->to(dstu, src, count))
+				goto fetch_fault;
+		}
+		ret = 0;
+		break;
+
+	case 1: /* mov.l Rm,@(disp,Rn) */
+		src = (unsigned char*) rm;
+		dstu = (unsigned char __user *)*rn;
+		dstu += (instruction&0x000F)<<2;
+
+		if (ma->to(dstu, 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;
+		dstu = (unsigned char __user *)*rn;
+#if !defined(__LITTLE_ENDIAN__)
+		src += 4-count;
+#endif
+		if (ma->to(dstu, src, count))
+			goto fetch_fault;
+		ret = 0;
+		break;
+
+	case 5: /* mov.l @(disp,Rm),Rn */
+		srcu = (unsigned char __user *)*rm;
+		srcu += (instruction & 0x000F) << 2;
+		dst = (unsigned char *)rn;
+		*(unsigned long *)dst = 0;
+
+		if (ma->from(dst, srcu, 4))
+			goto fetch_fault;
+		ret = 0;
+		break;
+
+	case 6:	/* mov.[bwl] from memory, possibly with post-increment */
+		srcu = (unsigned char __user *)*rm;
+		if (instruction & 4)
+			*rm += count;
+		dst = (unsigned char*) rn;
+		*(unsigned long*)dst = 0;
+
+#if !defined(__LITTLE_ENDIAN__)
+		dst += 4-count;
+#endif
+		if (ma->from(dst, srcu, count))
+			goto fetch_fault;
+		sign_extend(count, dst);
+		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
+			dstu = (unsigned char __user *)*rm; /* called Rn in the spec */
+			dstu += (instruction & 0x000F) << 1;
+
+			if (ma->to(dstu, src, 2))
+				goto fetch_fault;
+			ret = 0;
+			break;
+
+		case 0x85: /* mov.w @(disp,Rm),R0 */
+			srcu = (unsigned char __user *)*rm;
+			srcu += (instruction & 0x000F) << 1;
+			dst = (unsigned char *) &regs->regs[0];
+			*(unsigned long *)dst = 0;
+
+#if !defined(__LITTLE_ENDIAN__)
+			dst += 2;
+#endif
+			if (ma->from(dst, srcu, 2))
+				goto fetch_fault;
+			sign_extend(2, dst);
+			ret = 0;
+			break;
+		}
+		break;
+
+	case 9: /* mov.w @(disp,PC),Rn */
+		srcu = (unsigned char __user *)regs->pc;
+		srcu += 4;
+		srcu += (instruction & 0x00FF) << 1;
+		dst = (unsigned char *)rn;
+		*(unsigned long *)dst = 0;
+
+#if !defined(__LITTLE_ENDIAN__)
+		dst += 2;
+#endif
+
+		if (ma->from(dst, srcu, 2))
+			goto fetch_fault;
+		sign_extend(2, dst);
+		ret = 0;
+		break;
+
+	case 0xd: /* mov.l @(disp,PC),Rn */
+		srcu = (unsigned char __user *)(regs->pc & ~0x3);
+		srcu += 4;
+		srcu += (instruction & 0x00FF) << 2;
+		dst = (unsigned char *)rn;
+		*(unsigned long *)dst = 0;
+
+		if (ma->from(dst, srcu, 4))
+			goto fetch_fault;
+		ret = 0;
+		break;
+	}
+	return ret;
+
+ fetch_fault:
+	/* Argh. Address not only misaligned but also non-existent.
+	 * Raise an EFAULT and see if it's trapped
+	 */
+	die_if_no_fixup("Fault in unaligned fixup", regs, 0);
+	return -EFAULT;
+}
+
+/*
+ * emulate the instruction in the delay slot
+ * - fetches the instruction from PC+2
+ */
+static inline int handle_delayslot(struct pt_regs *regs,
+				   insn_size_t old_instruction,
+				   struct mem_access *ma)
+{
+	insn_size_t instruction;
+	void __user *addr = (void __user *)(regs->pc +
+		instruction_size(old_instruction));
+
+	if (copy_from_user(&instruction, addr, sizeof(instruction))) {
+		/* 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, ma);
+}
+
+/*
+ * 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)
+
+int handle_unaligned_access(insn_size_t instruction, struct pt_regs *regs,
+			    struct mem_access *ma, int expected,
+			    unsigned long address)
+{
+	u_int rm;
+	int ret, index;
+
+	/*
+	 * XXX: We can't handle mixed 16/32-bit instructions yet
+	 */
+	if (instruction_size(instruction) != 2)
+		return -EINVAL;
+
+	index = (instruction>>8)&15;	/* 0x0F00 */
+	rm = regs->regs[index];
+
+	/*
+	 * Log the unexpected fixups, and then pass them on to perf.
+	 *
+	 * We intentionally don't report the expected cases to perf as
+	 * otherwise the trapped I/O case will skew the results too much
+	 * to be useful.
+	 */
+	if (!expected) {
+		unaligned_fixups_notify(current, instruction, regs);
+		perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1,
+			      regs, address);
+	}
+
+	ret = -EFAULT;
+	switch (instruction&0xF000) {
+	case 0x0000:
+		if (instruction==0x000B) {
+			/* rts */
+			ret = handle_delayslot(regs, instruction, ma);
+			if (ret==0)
+				regs->pc = regs->pr;
+		}
+		else if ((instruction&0x00FF)==0x0023) {
+			/* braf @Rm */
+			ret = handle_delayslot(regs, instruction, ma);
+			if (ret==0)
+				regs->pc += rm + 4;
+		}
+		else if ((instruction&0x00FF)==0x0003) {
+			/* bsrf @Rm */
+			ret = handle_delayslot(regs, instruction, ma);
+			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_delayslot(regs, instruction, ma);
+			if (ret==0)
+				regs->pc = rm;
+		}
+		else if ((instruction&0x00FF)==0x000B) {
+			/* jsr @Rm */
+			ret = handle_delayslot(regs, instruction, ma);
+			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*/
+			ret = 0;
+			break;
+		case 0x0F00: /* bf/s lab */
+			ret = handle_delayslot(regs, instruction, ma);
+			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 */
+			ret = 0;
+			break;
+		case 0x0D00: /* bt/s lab */
+			ret = handle_delayslot(regs, instruction, ma);
+			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 0x9000: /* mov.w @(disp,Rm),Rn */
+		goto simple;
+
+	case 0xA000: /* bra label */
+		ret = handle_delayslot(regs, instruction, ma);
+		if (ret==0)
+			regs->pc += SH_PC_12BIT_OFFSET(instruction);
+		break;
+
+	case 0xB000: /* bsr label */
+		ret = handle_delayslot(regs, instruction, ma);
+		if (ret==0) {
+			regs->pr = regs->pc + 4;
+			regs->pc += SH_PC_12BIT_OFFSET(instruction);
+		}
+		break;
+
+	case 0xD000: /* mov.l @(disp,Rm),Rn */
+		goto simple;
+	}
+	return ret;
+
+	/* handle non-delay-slot instruction */
+ simple:
+	ret = handle_unaligned_ins(instruction, regs, ma);
+	if (ret==0)
+		regs->pc += instruction_size(instruction);
+	return ret;
+}
+
+/*
+ * 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;
+	insn_size_t instruction;
+	int tmp;
+
+	/* Intentional ifdef */
+#ifdef CONFIG_CPU_HAS_SR_RB
+	error_code = lookup_exception_vector();
+#endif
+
+	oldfs = get_fs();
+
+	if (user_mode(regs)) {
+		int si_code = BUS_ADRERR;
+		unsigned int user_action;
+
+		local_irq_enable();
+		inc_unaligned_user_access();
+
+		set_fs(USER_DS);
+		if (copy_from_user(&instruction, (insn_size_t *)(regs->pc & ~1),
+				   sizeof(instruction))) {
+			set_fs(oldfs);
+			goto uspace_segv;
+		}
+		set_fs(oldfs);
+
+		/* shout about userspace fixups */
+		unaligned_fixups_notify(current, instruction, regs);
+
+		user_action = unaligned_user_action();
+		if (user_action & UM_FIXUP)
+			goto fixup;
+		if (user_action & UM_SIGNAL)
+			goto uspace_segv;
+		else {
+			/* ignore */
+			regs->pc += instruction_size(instruction);
+			return;
+		}
+
+fixup:
+		/* bad PC is not something we can fix */
+		if (regs->pc & 1) {
+			si_code = BUS_ADRALN;
+			goto uspace_segv;
+		}
+
+		set_fs(USER_DS);
+		tmp = handle_unaligned_access(instruction, regs,
+					      &user_mem_access, 0,
+					      address);
+		set_fs(oldfs);
+
+		if (tmp == 0)
+			return; /* sorted */
+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 {
+		inc_unaligned_kernel_access();
+
+		if (regs->pc & 1)
+			die("unaligned program counter", regs, error_code);
+
+		set_fs(KERNEL_DS);
+		if (copy_from_user(&instruction, (void __user *)(regs->pc),
+				   sizeof(instruction))) {
+			/* Argh. Fault on the instruction itself.
+			   This should never happen non-SMP
+			*/
+			set_fs(oldfs);
+			die("insn faulting in do_address_error", regs, 0);
+		}
+
+		unaligned_fixups_notify(current, instruction, regs);
+
+		handle_unaligned_access(instruction, regs, &user_mem_access,
+					0, address);
+		set_fs(oldfs);
+	}
+}
+
+#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)
+{
+	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
+
+asmlinkage void do_reserved_inst(void)
+{
+	struct pt_regs *regs = current_pt_regs();
+	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;
+		/* Save DSP mode */
+		tsk->thread.dsp_status.status |= SR_DSP;
+		return;
+	}
+#endif
+
+	error_code = lookup_exception_vector();
+
+	local_irq_enable();
+	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 & 0xf000) == 0xb000)  ||	/* bsr */
+	    ((inst & 0xf0ff) == 0x0003)  ||	/* bsrf */
+	    ((inst & 0xf0ff) == 0x400b))	/* jsr */
+		regs->pr = regs->pc + 4;
+
+	if ((inst & 0xfd00) == 0x8d00) {	/* bfs, bts */
+		regs->pc += SH_PC_8BIT_OFFSET(inst);
+		return 0;
+	}
+
+	if ((inst & 0xe000) == 0xa000) {	/* bra, bsr */
+		regs->pc += SH_PC_12BIT_OFFSET(inst);
+		return 0;
+	}
+
+	if ((inst & 0xf0df) == 0x0003) {	/* braf, bsrf */
+		regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
+		return 0;
+	}
+
+	if ((inst & 0xf0df) == 0x400b) {	/* jmp, jsr */
+		regs->pc = regs->regs[(inst & 0x0f00) >> 8];
+		return 0;
+	}
+
+	if ((inst & 0xffff) == 0x000b) {	/* rts */
+		regs->pc = regs->pr;
+		return 0;
+	}
+
+	return 1;
+}
+#endif
+
+asmlinkage void do_illegal_slot_inst(void)
+{
+	struct pt_regs *regs = current_pt_regs();
+	unsigned long inst;
+	struct task_struct *tsk = current;
+
+	if (kprobe_handle_illslot(regs->pc) == 0)
+		return;
+
+#ifdef CONFIG_SH_FPU_EMU
+	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
+
+	inst = lookup_exception_vector();
+
+	local_irq_enable();
+	force_sig(SIGILL, tsk);
+	die_if_no_fixup("illegal slot instruction", regs, inst);
+}
+
+asmlinkage void do_exception_error(void)
+{
+	long ex;
+
+	ex = lookup_exception_vector();
+	die_if_kernel("exception", current_pt_regs(), ex);
+}
+
+void per_cpu_trap_init(void)
+{
+	extern void *vbr_base;
+
+	/* 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");
+
+	/* disable exception blocking now when the vbr has been setup */
+	clear_bl_bit();
+}
+
+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;
+}
+
+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)
+	set_exception_table_evt(0x800, fpu_state_restore_trap_handler);
+	set_exception_table_evt(0x820, fpu_state_restore_trap_handler);
+#endif
+
+#ifdef CONFIG_CPU_SH2
+	set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_trap_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);
+#ifdef CONFIG_SH_FPU
+	set_exception_table_vec(TRAP_FPU_ERROR, fpu_error_trap_handler);
+#endif
+#endif
+
+#ifdef TRAP_UBC
+	set_exception_table_vec(TRAP_UBC, breakpoint_trap_handler);
+#endif
+}