/*
   * arch/score/kernel/ptrace.c
   *
   * Score Processor version.
   *
   * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
   *  Chen Liqin <liqin.chen@sunplusct.com>
   *  Lennox Wu <lennox.wu@sunplusct.com>
   *
   * 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.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, see the file COPYING, or write
   * to the Free Software Foundation, Inc.,
   * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   */

  #include <linux/elf.h>

  #include <linux/kernel.h>

  #include <linux/mm.h>

  #include <linux/ptrace.h>

  #include <linux/regset.h>

  
  #include <asm/uaccess.h>

  /*
   * retrieve the contents of SCORE userspace general registers
   */
  static int genregs_get(struct task_struct *target,
  		       const struct user_regset *regset,
  		       unsigned int pos, unsigned int count,
  		       void *kbuf, void __user *ubuf)
  {
  	const struct pt_regs *regs = task_pt_regs(target);
  	int ret;
  
  	/* skip 9 * sizeof(unsigned long) not use for pt_regs */
  	ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
  					0, offsetof(struct pt_regs, regs));
  
  	/* r0 - r31, cel, ceh, sr0, sr1, sr2, epc, ema, psr, ecr, condition */
  	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  				  regs->regs,
  				  offsetof(struct pt_regs, regs),
  				  offsetof(struct pt_regs, cp0_condition));
  
  	if (!ret)
  		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
  						sizeof(struct pt_regs), -1);
  
  	return ret;
  }
  
  /*
   * update the contents of the SCORE userspace general registers
   */
  static int genregs_set(struct task_struct *target,
  		       const struct user_regset *regset,
  		       unsigned int pos, unsigned int count,
  		       const void *kbuf, const void __user *ubuf)
  {
  	struct pt_regs *regs = task_pt_regs(target);
  	int ret;
  
  	/* skip 9 * sizeof(unsigned long) */
  	ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
  					0, offsetof(struct pt_regs, regs));
  
  	/* r0 - r31, cel, ceh, sr0, sr1, sr2, epc, ema, psr, ecr, condition */
  	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
  				  regs->regs,
  				  offsetof(struct pt_regs, regs),
  				  offsetof(struct pt_regs, cp0_condition));
  
  	if (!ret)
  		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
  						sizeof(struct pt_regs), -1);
  
  	return ret;
  }
  
  /*
   * Define the register sets available on the score7 under Linux
   */
  enum score7_regset {
  	REGSET_GENERAL,
  };
  
  static const struct user_regset score7_regsets[] = {
  	[REGSET_GENERAL] = {
  		.core_note_type	= NT_PRSTATUS,
  		.n		= ELF_NGREG,
  		.size		= sizeof(long),
  		.align		= sizeof(long),
  		.get		= genregs_get,
  		.set		= genregs_set,
  	},
  };
  
  static const struct user_regset_view user_score_native_view = {
  	.name		= "score7",
  	.e_machine	= EM_SCORE7,
  	.regsets	= score7_regsets,
  	.n		= ARRAY_SIZE(score7_regsets),
  };
  
  const struct user_regset_view *task_user_regset_view(struct task_struct *task)
  {
  	return &user_score_native_view;
  }

  static int is_16bitinsn(unsigned long insn)
  {
  	if ((insn & INSN32_MASK) == INSN32_MASK)
  		return 0;
  	else
  		return 1;
  }
  
  int
  read_tsk_long(struct task_struct *child,
  		unsigned long addr, unsigned long *res)
  {
  	int copied;
  
  	copied = access_process_vm(child, addr, res, sizeof(*res), 0);
  
  	return copied != sizeof(*res) ? -EIO : 0;
  }
  
  int
  read_tsk_short(struct task_struct *child,
  		unsigned long addr, unsigned short *res)
  {
  	int copied;
  
  	copied = access_process_vm(child, addr, res, sizeof(*res), 0);
  
  	return copied != sizeof(*res) ? -EIO : 0;
  }
  
  static int
  write_tsk_short(struct task_struct *child,
  		unsigned long addr, unsigned short val)
  {
  	int copied;
  
  	copied = access_process_vm(child, addr, &val, sizeof(val), 1);
  
  	return copied != sizeof(val) ? -EIO : 0;
  }
  
  static int
  write_tsk_long(struct task_struct *child,
  		unsigned long addr, unsigned long val)
  {
  	int copied;
  
  	copied = access_process_vm(child, addr, &val, sizeof(val), 1);
  
  	return copied != sizeof(val) ? -EIO : 0;
  }

  void user_enable_single_step(struct task_struct *child)

  {
  	/* far_epc is the target of branch */
  	unsigned int epc, far_epc = 0;
  	unsigned long epc_insn, far_epc_insn;
  	int ninsn_type;			/* next insn type 0=16b, 1=32b */
  	unsigned int tmp, tmp2;
  	struct pt_regs *regs = task_pt_regs(child);
  	child->thread.single_step = 1;
  	child->thread.ss_nextcnt = 1;
  	epc = regs->cp0_epc;
  
  	read_tsk_long(child, epc, &epc_insn);
  
  	if (is_16bitinsn(epc_insn)) {
  		if ((epc_insn & J16M) == J16) {
  			tmp = epc_insn & 0xFFE;
  			epc = (epc & 0xFFFFF000) | tmp;
  		} else if ((epc_insn & B16M) == B16) {
  			child->thread.ss_nextcnt = 2;
  			tmp = (epc_insn & 0xFF) << 1;
  			tmp = tmp << 23;
  			tmp = (unsigned int)((int) tmp >> 23);
  			far_epc = epc + tmp;
  			epc += 2;
  		} else if ((epc_insn & BR16M) == BR16) {
  			child->thread.ss_nextcnt = 2;
  			tmp = (epc_insn >> 4) & 0xF;
  			far_epc = regs->regs[tmp];
  			epc += 2;
  		} else
  			epc += 2;
  	} else {
  		if ((epc_insn & J32M) == J32) {
  			tmp = epc_insn & 0x03FFFFFE;
  			tmp2 = tmp & 0x7FFF;
  			tmp = (((tmp >> 16) & 0x3FF) << 15) | tmp2;
  			epc = (epc & 0xFFC00000) | tmp;
  		} else if ((epc_insn & B32M) == B32) {
  			child->thread.ss_nextcnt = 2;
  			tmp = epc_insn & 0x03FFFFFE;	/* discard LK bit */
  			tmp2 = tmp & 0x3FF;
  			tmp = (((tmp >> 16) & 0x3FF) << 10) | tmp2; /* 20bit */
  			tmp = tmp << 12;
  			tmp = (unsigned int)((int) tmp >> 12);
  			far_epc = epc + tmp;
  			epc += 4;
  		} else if ((epc_insn & BR32M) == BR32) {
  			child->thread.ss_nextcnt = 2;
  			tmp = (epc_insn >> 16) & 0x1F;
  			far_epc = regs->regs[tmp];
  			epc += 4;
  		} else
  			epc += 4;
  	}
  
  	if (child->thread.ss_nextcnt == 1) {
  		read_tsk_long(child, epc, &epc_insn);
  
  		if (is_16bitinsn(epc_insn)) {
  			write_tsk_short(child, epc, SINGLESTEP16_INSN);
  			ninsn_type = 0;
  		} else {
  			write_tsk_long(child, epc, SINGLESTEP32_INSN);
  			ninsn_type = 1;
  		}
  
  		if (ninsn_type == 0) {  /* 16bits */
  			child->thread.insn1_type = 0;
  			child->thread.addr1 = epc;
  			 /* the insn may have 32bit data */
  			child->thread.insn1 = (short)epc_insn;
  		} else {
  			child->thread.insn1_type = 1;
  			child->thread.addr1 = epc;
  			child->thread.insn1 = epc_insn;
  		}
  	} else {
  		/* branch! have two target child->thread.ss_nextcnt=2 */
  		read_tsk_long(child, epc, &epc_insn);
  		read_tsk_long(child, far_epc, &far_epc_insn);
  		if (is_16bitinsn(epc_insn)) {
  			write_tsk_short(child, epc, SINGLESTEP16_INSN);
  			ninsn_type = 0;
  		} else {
  			write_tsk_long(child, epc, SINGLESTEP32_INSN);
  			ninsn_type = 1;
  		}
  
  		if (ninsn_type == 0) {  /* 16bits */
  			child->thread.insn1_type = 0;
  			child->thread.addr1 = epc;
  			 /* the insn may have 32bit data */
  			child->thread.insn1 = (short)epc_insn;
  		} else {
  			child->thread.insn1_type = 1;
  			child->thread.addr1 = epc;
  			child->thread.insn1 = epc_insn;
  		}
  
  		if (is_16bitinsn(far_epc_insn)) {
  			write_tsk_short(child, far_epc, SINGLESTEP16_INSN);
  			ninsn_type = 0;
  		} else {
  			write_tsk_long(child, far_epc, SINGLESTEP32_INSN);
  			ninsn_type = 1;
  		}
  
  		if (ninsn_type == 0) {  /* 16bits */
  			child->thread.insn2_type = 0;
  			child->thread.addr2 = far_epc;
  			 /* the insn may have 32bit data */
  			child->thread.insn2 = (short)far_epc_insn;
  		} else {
  			child->thread.insn2_type = 1;
  			child->thread.addr2 = far_epc;
  			child->thread.insn2 = far_epc_insn;
  		}
  	}
  }

  void user_disable_single_step(struct task_struct *child)

  {
  	if (child->thread.insn1_type == 0)
  		write_tsk_short(child, child->thread.addr1,
  				child->thread.insn1);
  
  	if (child->thread.insn1_type == 1)
  		write_tsk_long(child, child->thread.addr1,
  				child->thread.insn1);
  
  	if (child->thread.ss_nextcnt == 2) {	/* branch */
  		if (child->thread.insn1_type == 0)
  			write_tsk_short(child, child->thread.addr1,
  					child->thread.insn1);
  		if (child->thread.insn1_type == 1)
  			write_tsk_long(child, child->thread.addr1,
  					child->thread.insn1);
  		if (child->thread.insn2_type == 0)
  			write_tsk_short(child, child->thread.addr2,
  					child->thread.insn2);
  		if (child->thread.insn2_type == 1)
  			write_tsk_long(child, child->thread.addr2,
  					child->thread.insn2);
  	}
  
  	child->thread.single_step = 0;
  	child->thread.ss_nextcnt = 0;
  }

  void ptrace_disable(struct task_struct *child)
  {
  	user_disable_single_step(child);
  }

  
  long

  arch_ptrace(struct task_struct *child, long request,
  	    unsigned long addr, unsigned long data)

  {
  	int ret;

  	unsigned long __user *datap = (void __user *)data;

  	switch (request) {

  	case PTRACE_GETREGS:

  		ret = copy_regset_to_user(child, &user_score_native_view,
  						REGSET_GENERAL,
  						0, sizeof(struct pt_regs),

  						datap);

  		break;

  	case PTRACE_SETREGS:

  		ret = copy_regset_from_user(child, &user_score_native_view,
  						REGSET_GENERAL,
  						0, sizeof(struct pt_regs),

  						datap);

  		break;
  
  	default:

  		ret = ptrace_request(child, request, addr, data);

  		break;
  	}
  
  	return ret;
  }
  
  /*
   * Notification of system call entry/exit
   * - triggered by current->work.syscall_trace
   */
  asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
  {
  	if (!(current->ptrace & PT_PTRACED))
  		return;
  
  	if (!test_thread_flag(TIF_SYSCALL_TRACE))
  		return;
  
  	/* The 0x80 provides a way for the tracing parent to distinguish
  	   between a syscall stop and SIGTRAP delivery. */
  	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ?
  			0x80 : 0));
  
  	/*
  	 * this isn't the same as continuing with a signal, but it will do
  	 * for normal use.  strace only continues with a signal if the
  	 * stopping signal is not SIGTRAP.  -brl
  	 */
  	if (current->exit_code) {
  		send_sig(current->exit_code, current, 1);
  		current->exit_code = 0;
  	}
  }