/*
 * Main exception handling logic.
 *
 * Copyright 2004-2010 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later
 */

#include <linux/bug.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <asm/traps.h>
#include <asm/cplb.h>
#include <asm/blackfin.h>
#include <asm/irq_handler.h>
#include <linux/irq.h>
#include <asm/trace.h>
#include <asm/fixed_code.h>
#include <asm/pseudo_instructions.h>
#include <asm/pda.h>

#ifdef CONFIG_KGDB
# include <linux/kgdb.h>

# define CHK_DEBUGGER_TRAP() \
	do { \
		kgdb_handle_exception(trapnr, sig, info.si_code, fp); \
	} while (0)
# define CHK_DEBUGGER_TRAP_MAYBE() \
	do { \
		if (kgdb_connected) \
			CHK_DEBUGGER_TRAP(); \
	} while (0)
#else
# define CHK_DEBUGGER_TRAP() do { } while (0)
# define CHK_DEBUGGER_TRAP_MAYBE() do { } while (0)
#endif


#ifdef CONFIG_DEBUG_VERBOSE
#define verbose_printk(fmt, arg...) \
	printk(fmt, ##arg)
#else
#define verbose_printk(fmt, arg...) \
	({ if (0) printk(fmt, ##arg); 0; })
#endif

#if defined(CONFIG_DEBUG_MMRS) || defined(CONFIG_DEBUG_MMRS_MODULE)
u32 last_seqstat;
#ifdef CONFIG_DEBUG_MMRS_MODULE
EXPORT_SYMBOL(last_seqstat);
#endif
#endif

/* Initiate the event table handler */
void __init trap_init(void)
{
	CSYNC();
	bfin_write_EVT3(trap);
	CSYNC();
}

static int kernel_mode_regs(struct pt_regs *regs)
{
	return regs->ipend & 0xffc0;
}

asmlinkage notrace void trap_c(struct pt_regs *fp)
{
#ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
	int j;
#endif
#ifdef CONFIG_BFIN_PSEUDODBG_INSNS
	int opcode;
#endif
	unsigned int cpu = raw_smp_processor_id();
	const char *strerror = NULL;
	int sig = 0;
	siginfo_t info;
	unsigned long trapnr = fp->seqstat & SEQSTAT_EXCAUSE;

	trace_buffer_save(j);
#if defined(CONFIG_DEBUG_MMRS) || defined(CONFIG_DEBUG_MMRS_MODULE)
	last_seqstat = (u32)fp->seqstat;
#endif

	/* Important - be very careful dereferncing pointers - will lead to
	 * double faults if the stack has become corrupt
	 */

	/* trap_c() will be called for exceptions. During exceptions
	 * processing, the pc value should be set with retx value.
	 * With this change we can cleanup some code in signal.c- TODO
	 */
	fp->orig_pc = fp->retx;
	/* printk("exception: 0x%x, ipend=%x, reti=%x, retx=%x\n",
		trapnr, fp->ipend, fp->pc, fp->retx); */

	/* send the appropriate signal to the user program */
	switch (trapnr) {

	/* This table works in conjunction with the one in ./mach-common/entry.S
	 * Some exceptions are handled there (in assembly, in exception space)
	 * Some are handled here, (in C, in interrupt space)
	 * Some, like CPLB, are handled in both, where the normal path is
	 * handled in assembly/exception space, and the error path is handled
	 * here
	 */

	/* 0x00 - Linux Syscall, getting here is an error */
	/* 0x01 - userspace gdb breakpoint, handled here */
	case VEC_EXCPT01:
		info.si_code = TRAP_ILLTRAP;
		sig = SIGTRAP;
		CHK_DEBUGGER_TRAP_MAYBE();
		/* Check if this is a breakpoint in kernel space */
		if (kernel_mode_regs(fp))
			goto traps_done;
		else
			break;
	/* 0x03 - User Defined, userspace stack overflow */
	case VEC_EXCPT03:
		info.si_code = SEGV_STACKFLOW;
		sig = SIGSEGV;
		strerror = KERN_NOTICE EXC_0x03(KERN_NOTICE);
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
	/* 0x02 - KGDB initial connection and break signal trap */
	case VEC_EXCPT02:
#ifdef CONFIG_KGDB
		info.si_code = TRAP_ILLTRAP;
		sig = SIGTRAP;
		CHK_DEBUGGER_TRAP();
		goto traps_done;
#endif
	/* 0x04 - User Defined */