/*
   *  Originally written by Glenn Engel, Lake Stevens Instrument Division
   *
   *  Contributed by HP Systems
   *
   *  Modified for Linux/MIPS (and MIPS in general) by Andreas Busse
   *  Send complaints, suggestions etc. to <andy@waldorf-gmbh.de>
   *
   *  Copyright (C) 1995 Andreas Busse
   *
   *  Copyright (C) 2003 MontaVista Software Inc.
   *  Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
   *
   *  Copyright (C) 2004-2005 MontaVista Software Inc.
   *  Author: Manish Lachwani, mlachwani@mvista.com or manish@koffee-break.com
   *
   *  Copyright (C) 2007-2008 Wind River Systems, Inc.
   *  Author/Maintainer: Jason Wessel, jason.wessel@windriver.com
   *
   *  This file is licensed under the terms of the GNU General Public License
   *  version 2. This program is licensed "as is" without any warranty of any
   *  kind, whether express or implied.
   */
  
  #include <linux/ptrace.h>		/* for linux pt_regs struct */
  #include <linux/kgdb.h>
  #include <linux/kdebug.h>
  #include <linux/sched.h>

  #include <linux/smp.h>

  #include <asm/inst.h>
  #include <asm/fpu.h>
  #include <asm/cacheflush.h>
  #include <asm/processor.h>
  #include <asm/sigcontext.h>
  
  static struct hard_trap_info {
  	unsigned char tt;	/* Trap type code for MIPS R3xxx and R4xxx */
  	unsigned char signo;	/* Signal that we map this trap into */
  } hard_trap_info[] = {
  	{ 6, SIGBUS },		/* instruction bus error */
  	{ 7, SIGBUS },		/* data bus error */
  	{ 9, SIGTRAP },		/* break */
  /*	{ 11, SIGILL },	*/	/* CPU unusable */
  	{ 12, SIGFPE },		/* overflow */
  	{ 13, SIGTRAP },	/* trap */
  	{ 14, SIGSEGV },	/* virtual instruction cache coherency */
  	{ 15, SIGFPE },		/* floating point exception */
  	{ 23, SIGSEGV },	/* watch */
  	{ 31, SIGSEGV },	/* virtual data cache coherency */
  	{ 0, 0}			/* Must be last */
  };

  struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
  {
  	{ "zero", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[0]) },
  	{ "at", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[1]) },
  	{ "v0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[2]) },
  	{ "v1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[3]) },
  	{ "a0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[4]) },
  	{ "a1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[5]) },
  	{ "a2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[6]) },
  	{ "a3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[7]) },
  	{ "t0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[8]) },
  	{ "t1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[9]) },
  	{ "t2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[10]) },
  	{ "t3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[11]) },
  	{ "t4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[12]) },
  	{ "t5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[13]) },
  	{ "t6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[14]) },
  	{ "t7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[15]) },
  	{ "s0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[16]) },
  	{ "s1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[17]) },
  	{ "s2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[18]) },
  	{ "s3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[19]) },
  	{ "s4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[20]) },
  	{ "s5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[21]) },
  	{ "s6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[22]) },
  	{ "s7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[23]) },
  	{ "t8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[24]) },
  	{ "t9", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[25]) },
  	{ "k0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[26]) },
  	{ "k1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[27]) },
  	{ "gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[28]) },
  	{ "sp", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[29]) },
  	{ "s8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[30]) },
  	{ "ra", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[31]) },
  	{ "sr", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_status) },
  	{ "lo", GDB_SIZEOF_REG, offsetof(struct pt_regs, lo) },
  	{ "hi", GDB_SIZEOF_REG, offsetof(struct pt_regs, hi) },
  	{ "bad", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_badvaddr) },
  	{ "cause", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_cause) },
  	{ "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_epc) },
  	{ "f0", GDB_SIZEOF_REG, 0 },
  	{ "f1", GDB_SIZEOF_REG, 1 },
  	{ "f2", GDB_SIZEOF_REG, 2 },
  	{ "f3", GDB_SIZEOF_REG, 3 },
  	{ "f4", GDB_SIZEOF_REG, 4 },
  	{ "f5", GDB_SIZEOF_REG, 5 },
  	{ "f6", GDB_SIZEOF_REG, 6 },
  	{ "f7", GDB_SIZEOF_REG, 7 },
  	{ "f8", GDB_SIZEOF_REG, 8 },
  	{ "f9", GDB_SIZEOF_REG, 9 },
  	{ "f10", GDB_SIZEOF_REG, 10 },
  	{ "f11", GDB_SIZEOF_REG, 11 },
  	{ "f12", GDB_SIZEOF_REG, 12 },
  	{ "f13", GDB_SIZEOF_REG, 13 },
  	{ "f14", GDB_SIZEOF_REG, 14 },
  	{ "f15", GDB_SIZEOF_REG, 15 },
  	{ "f16", GDB_SIZEOF_REG, 16 },
  	{ "f17", GDB_SIZEOF_REG, 17 },
  	{ "f18", GDB_SIZEOF_REG, 18 },
  	{ "f19", GDB_SIZEOF_REG, 19 },
  	{ "f20", GDB_SIZEOF_REG, 20 },
  	{ "f21", GDB_SIZEOF_REG, 21 },
  	{ "f22", GDB_SIZEOF_REG, 22 },
  	{ "f23", GDB_SIZEOF_REG, 23 },
  	{ "f24", GDB_SIZEOF_REG, 24 },
  	{ "f25", GDB_SIZEOF_REG, 25 },
  	{ "f26", GDB_SIZEOF_REG, 26 },
  	{ "f27", GDB_SIZEOF_REG, 27 },
  	{ "f28", GDB_SIZEOF_REG, 28 },
  	{ "f29", GDB_SIZEOF_REG, 29 },
  	{ "f30", GDB_SIZEOF_REG, 30 },
  	{ "f31", GDB_SIZEOF_REG, 31 },
  	{ "fsr", GDB_SIZEOF_REG, 0 },
  	{ "fir", GDB_SIZEOF_REG, 0 },
  };
  
  int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
  {
  	int fp_reg;
  
  	if (regno < 0 || regno >= DBG_MAX_REG_NUM)
  		return -EINVAL;
  
  	if (dbg_reg_def[regno].offset != -1 && regno < 38) {
  		memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
  		       dbg_reg_def[regno].size);
  	} else if (current && dbg_reg_def[regno].offset != -1 && regno < 72) {
  		/* FP registers 38 -> 69 */
  		if (!(regs->cp0_status & ST0_CU1))
  			return 0;
  		if (regno == 70) {
  			/* Process the fcr31/fsr (register 70) */
  			memcpy((void *)&current->thread.fpu.fcr31, mem,
  			       dbg_reg_def[regno].size);
  			goto out_save;
  		} else if (regno == 71) {
  			/* Ignore the fir (register 71) */
  			goto out_save;
  		}
  		fp_reg = dbg_reg_def[regno].offset;
  		memcpy((void *)&current->thread.fpu.fpr[fp_reg], mem,
  		       dbg_reg_def[regno].size);
  out_save:
  		restore_fp(current);
  	}
  
  	return 0;
  }
  
  char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
  {
  	int fp_reg;
  
  	if (regno >= DBG_MAX_REG_NUM || regno < 0)
  		return NULL;
  
  	if (dbg_reg_def[regno].offset != -1 && regno < 38) {
  		/* First 38 registers */
  		memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
  		       dbg_reg_def[regno].size);
  	} else if (current && dbg_reg_def[regno].offset != -1 && regno < 72) {
  		/* FP registers 38 -> 69 */
  		if (!(regs->cp0_status & ST0_CU1))
  			goto out;
  		save_fp(current);
  		if (regno == 70) {
  			/* Process the fcr31/fsr (register 70) */
  			memcpy(mem, (void *)&current->thread.fpu.fcr31,
  			       dbg_reg_def[regno].size);
  			goto out;
  		} else if (regno == 71) {
  			/* Ignore the fir (register 71) */
  			memset(mem, 0, dbg_reg_def[regno].size);
  			goto out;
  		}
  		fp_reg = dbg_reg_def[regno].offset;
  		memcpy(mem, (void *)&current->thread.fpu.fpr[fp_reg],
  		       dbg_reg_def[regno].size);
  	}
  
  out:
  	return dbg_reg_def[regno].name;
  
  }

  void arch_kgdb_breakpoint(void)
  {
  	__asm__ __volatile__(
  		".globl breakinst
  \t"
  		".set\tnoreorder
  \t"
  		"nop
  "
  		"breakinst:\tbreak
  \t"
  		"nop
  \t"
  		".set\treorder");
  }
  
  static void kgdb_call_nmi_hook(void *ignored)
  {

  	kgdb_nmicallback(raw_smp_processor_id(), NULL);

  }
  
  void kgdb_roundup_cpus(unsigned long flags)
  {
  	local_irq_enable();

  	smp_call_function(kgdb_call_nmi_hook, NULL, 0);

  	local_irq_disable();
  }
  
  static int compute_signal(int tt)
  {
  	struct hard_trap_info *ht;
  
  	for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
  		if (ht->tt == tt)
  			return ht->signo;
  
  	return SIGHUP;		/* default for things we don't know about */
  }

  /*
   * Similar to regs_to_gdb_regs() except that process is sleeping and so
   * we may not be able to get all the info.
   */
  void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
  {
  	int reg;
  	struct thread_info *ti = task_thread_info(p);
  	unsigned long ksp = (unsigned long)ti + THREAD_SIZE - 32;
  	struct pt_regs *regs = (struct pt_regs *)ksp - 1;
  #if (KGDB_GDB_REG_SIZE == 32)
  	u32 *ptr = (u32 *)gdb_regs;
  #else
  	u64 *ptr = (u64 *)gdb_regs;
  #endif
  
  	for (reg = 0; reg < 16; reg++)
  		*(ptr++) = regs->regs[reg];
  
  	/* S0 - S7 */
  	for (reg = 16; reg < 24; reg++)
  		*(ptr++) = regs->regs[reg];
  
  	for (reg = 24; reg < 28; reg++)
  		*(ptr++) = 0;
  
  	/* GP, SP, FP, RA */
  	for (reg = 28; reg < 32; reg++)
  		*(ptr++) = regs->regs[reg];
  
  	*(ptr++) = regs->cp0_status;
  	*(ptr++) = regs->lo;
  	*(ptr++) = regs->hi;
  	*(ptr++) = regs->cp0_badvaddr;
  	*(ptr++) = regs->cp0_cause;
  	*(ptr++) = regs->cp0_epc;
  }

  void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
  {
  	regs->cp0_epc = pc;
  }

  /*
   * Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
   * then try to fall into the debugger
   */
  static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
  			    void *ptr)
  {
  	struct die_args *args = (struct die_args *)ptr;
  	struct pt_regs *regs = args->regs;
  	int trap = (regs->cp0_cause & 0x7c) >> 2;

  	/* Userspace events, ignore. */

  	if (user_mode(regs))
  		return NOTIFY_DONE;
  
  	if (atomic_read(&kgdb_active) != -1)
  		kgdb_nmicallback(smp_processor_id(), regs);

  	if (kgdb_handle_exception(trap, compute_signal(trap), cmd, regs))

  		return NOTIFY_DONE;
  
  	if (atomic_read(&kgdb_setting_breakpoint))
  		if ((trap == 9) && (regs->cp0_epc == (unsigned long)breakinst))
  			regs->cp0_epc += 4;
  
  	/* In SMP mode, __flush_cache_all does IPI */
  	local_irq_enable();
  	__flush_cache_all();
  
  	return NOTIFY_STOP;
  }

  #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
  int kgdb_ll_trap(int cmd, const char *str,
  		 struct pt_regs *regs, long err, int trap, int sig)
  {
  	struct die_args args = {
  		.regs	= regs,
  		.str	= str,
  		.err	= err,
  		.trapnr	= trap,
  		.signr	= sig,
  
  	};
  
  	if (!kgdb_io_module_registered)
  		return NOTIFY_DONE;
  
  	return kgdb_mips_notify(NULL, cmd, &args);
  }
  #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */

  static struct notifier_block kgdb_notifier = {
  	.notifier_call = kgdb_mips_notify,
  };
  
  /*

   * Handle the 'c' command

   */
  int kgdb_arch_handle_exception(int vector, int signo, int err_code,
  			       char *remcom_in_buffer, char *remcom_out_buffer,
  			       struct pt_regs *regs)
  {
  	char *ptr;
  	unsigned long address;

  
  	switch (remcom_in_buffer[0]) {

  	case 'c':
  		/* handle the optional parameter */
  		ptr = &remcom_in_buffer[1];
  		if (kgdb_hex2long(&ptr, &address))
  			regs->cp0_epc = address;

  		return 0;
  	}
  
  	return -1;
  }
  
  struct kgdb_arch arch_kgdb_ops;
  
  /*
   * We use kgdb_early_setup so that functions we need to call now don't
   * cause trouble when called again later.
   */
  int kgdb_arch_init(void)
  {
  	union mips_instruction insn = {
  		.r_format = {
  			.opcode = spec_op,
  			.func   = break_op,
  		}
  	};
  	memcpy(arch_kgdb_ops.gdb_bpt_instr, insn.byte, BREAK_INSTR_SIZE);
  
  	register_die_notifier(&kgdb_notifier);
  
  	return 0;
  }
  
  /*
   *	kgdb_arch_exit - Perform any architecture specific uninitalization.
   *
   *	This function will handle the uninitalization of any architecture
   *	specific callbacks, for dynamic registration and unregistration.
   */
  void kgdb_arch_exit(void)
  {
  	unregister_die_notifier(&kgdb_notifier);
  }