text: /*
   * Copyright 2014 Google Inc.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License as
   * published by the Free Software Foundation; either version 2 of
   * the License, or (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but without any warranty; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   */
  
  #include <exception.h>
  #include <gdb.h>
  #include <libpayload.h>
  
  static const u8 type_to_signal[] = {
  	[EXC_DE]  = GDB_SIGFPE,
  	[EXC_DB]  = GDB_SIGTRAP,
  	[EXC_NMI] = GDB_SIGKILL,
  	[EXC_BP]  = GDB_SIGTRAP,
  	[EXC_OF]  = GDB_SIGFPE,
  	[EXC_BR]  = GDB_SIGSEGV,
  	[EXC_UD]  = GDB_SIGILL,
  	[EXC_NM]  = GDB_SIGEMT,
  	[EXC_DF]  = GDB_SIGKILL,
  	[EXC_TS]  = GDB_SIGSEGV,
  	[EXC_NP]  = GDB_SIGSEGV,
  	[EXC_SS]  = GDB_SIGBUS,
  	[EXC_GP]  = GDB_SIGSEGV,
  	[EXC_PF]  = GDB_SIGSEGV,
  	[EXC_MF]  = GDB_SIGEMT,
  	[EXC_AC]  = GDB_SIGBUS,
  	[EXC_MC]  = GDB_SIGKILL,
  	[EXC_XF]  = GDB_SIGFPE,
  	[EXC_SX]  = GDB_SIGFPE,
  };
  
  static int gdb_exception_hook(u32 type)
  {
  	if (type >= ARRAY_SIZE(type_to_signal) || !type_to_signal[type])
  		return 0;
  	gdb_command_loop(type_to_signal[type]);
  	return 1;
  }
  
  void gdb_arch_init(void)
  {
  	exception_install_hook(&gdb_exception_hook);
  }
  
  void gdb_arch_enter(void)
  {
  	u32 *esp;
  
  	asm volatile ("mov %%esp, %0" : "=r"(esp) );
  
  	/* Avoid reentrant exceptions, just call the hook if in one already. */
  	if (esp >= exception_stack && esp <= exception_stack_end)
  		gdb_exception_hook(EXC_BP);
  	else
  		asm volatile ("int3");
  }
  
  int gdb_arch_set_single_step(int on)
  {
  	const u32 tf_bit = 1 << 8;
  
  	if (on)
  		exception_state->regs.eflags |= tf_bit;
  	else
  		exception_state->regs.eflags &= ~tf_bit;
  
  	return 0;
  }
  
  void gdb_arch_encode_regs(struct gdb_message *message)
  {
  	gdb_message_encode_bytes(message, &exception_state->regs,
  				 sizeof(exception_state->regs));
  }
  
  void gdb_arch_decode_regs(int offset, struct gdb_message *message)
  {
  	gdb_message_decode_bytes(message, offset, &exception_state->regs,
  				 sizeof(exception_state->regs));
  }
  