/*

   * arch/sh/kernel/ptrace_64.c

   *
   * Copyright (C) 2000, 2001  Paolo Alberelli

   * Copyright (C) 2003 - 2008  Paul Mundt

   *
   * Started from SH3/4 version:
   *   SuperH version:   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
   *
   *   Original x86 implementation:
   *	By Ross Biro 1/23/92
   *	edited by Linus Torvalds
   *

   * 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/rwsem.h>
  #include <linux/sched.h>
  #include <linux/mm.h>
  #include <linux/smp.h>

  #include <linux/bitops.h>

  #include <linux/errno.h>
  #include <linux/ptrace.h>
  #include <linux/user.h>

  #include <linux/signal.h>

  #include <linux/syscalls.h>

  #include <linux/audit.h>

  #include <linux/seccomp.h>

  #include <linux/tracehook.h>

  #include <linux/elf.h>
  #include <linux/regset.h>

  #include <asm/io.h>
  #include <asm/uaccess.h>
  #include <asm/pgtable.h>
  #include <asm/system.h>
  #include <asm/processor.h>
  #include <asm/mmu_context.h>

  #include <asm/syscalls.h>

  #include <asm/fpu.h>

  #define CREATE_TRACE_POINTS
  #include <trace/events/syscalls.h>

  /* This mask defines the bits of the SR which the user is not allowed to
     change, which are everything except S, Q, M, PR, SZ, FR. */
  #define SR_MASK      (0xffff8cfd)
  
  /*
   * does not yet catch signals sent when the child dies.
   * in exit.c or in signal.c.
   */
  
  /*
   * This routine will get a word from the user area in the process kernel stack.
   */
  static inline int get_stack_long(struct task_struct *task, int offset)
  {
  	unsigned char *stack;
  
  	stack = (unsigned char *)(task->thread.uregs);
  	stack += offset;
  	return (*((int *)stack));
  }
  
  static inline unsigned long
  get_fpu_long(struct task_struct *task, unsigned long addr)
  {
  	unsigned long tmp;
  	struct pt_regs *regs;
  	regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
  
  	if (!tsk_used_math(task)) {
  		if (addr == offsetof(struct user_fpu_struct, fpscr)) {
  			tmp = FPSCR_INIT;
  		} else {
  			tmp = 0xffffffffUL; /* matches initial value in fpu.c */
  		}
  		return tmp;
  	}
  
  	if (last_task_used_math == task) {

  		enable_fpu();

  		save_fpu(task);

  		disable_fpu();

  		last_task_used_math = 0;
  		regs->sr |= SR_FD;
  	}

  	tmp = ((long *)task->thread.xstate)[addr / sizeof(unsigned long)];

  	return tmp;
  }
  
  /*
   * This routine will put a word into the user area in the process kernel stack.
   */
  static inline int put_stack_long(struct task_struct *task, int offset,
  				 unsigned long data)
  {
  	unsigned char *stack;
  
  	stack = (unsigned char *)(task->thread.uregs);
  	stack += offset;
  	*(unsigned long *) stack = data;
  	return 0;
  }
  
  static inline int
  put_fpu_long(struct task_struct *task, unsigned long addr, unsigned long data)
  {
  	struct pt_regs *regs;
  
  	regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
  
  	if (!tsk_used_math(task)) {

  		init_fpu(task);

  	} else if (last_task_used_math == task) {

  		enable_fpu();

  		save_fpu(task);

  		disable_fpu();

  		last_task_used_math = 0;
  		regs->sr |= SR_FD;
  	}

  	((long *)task->thread.xstate)[addr / sizeof(unsigned long)] = data;

  	return 0;
  }

  void user_enable_single_step(struct task_struct *child)
  {
  	struct pt_regs *regs = child->thread.uregs;
  
  	regs->sr |= SR_SSTEP;	/* auto-resetting upon exception */

  
  	set_tsk_thread_flag(child, TIF_SINGLESTEP);

  }
  
  void user_disable_single_step(struct task_struct *child)
  {

  	struct pt_regs *regs = child->thread.uregs;

  	regs->sr &= ~SR_SSTEP;

  
  	clear_tsk_thread_flag(child, TIF_SINGLESTEP);

  }

  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;
  
  	/* PC, SR, SYSCALL */
  	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  				  &regs->pc,
  				  0, 3 * sizeof(unsigned long long));
  
  	/* R1 -> R63 */
  	if (!ret)
  		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  					  regs->regs,
  					  offsetof(struct pt_regs, regs[0]),
  					  63 * sizeof(unsigned long long));
  	/* TR0 -> TR7 */
  	if (!ret)
  		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  					  regs->tregs,
  					  offsetof(struct pt_regs, tregs[0]),
  					  8 * sizeof(unsigned long long));
  
  	if (!ret)
  		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
  					       sizeof(struct pt_regs), -1);
  
  	return ret;
  }
  
  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;
  
  	/* PC, SR, SYSCALL */
  	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
  				 &regs->pc,
  				 0, 3 * sizeof(unsigned long long));
  
  	/* R1 -> R63 */
  	if (!ret && count > 0)
  		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
  					 regs->regs,
  					 offsetof(struct pt_regs, regs[0]),
  					 63 * sizeof(unsigned long long));
  
  	/* TR0 -> TR7 */
  	if (!ret && count > 0)
  		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
  					 regs->tregs,
  					 offsetof(struct pt_regs, tregs[0]),
  					 8 * sizeof(unsigned long long));
  
  	if (!ret)
  		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
  						sizeof(struct pt_regs), -1);
  
  	return ret;
  }
  
  #ifdef CONFIG_SH_FPU
  int fpregs_get(struct task_struct *target,
  	       const struct user_regset *regset,
  	       unsigned int pos, unsigned int count,
  	       void *kbuf, void __user *ubuf)
  {
  	int ret;
  
  	ret = init_fpu(target);
  	if (ret)
  		return ret;
  
  	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,

  				   &target->thread.xstate->hardfpu, 0, -1);

  }
  
  static int fpregs_set(struct task_struct *target,
  		       const struct user_regset *regset,
  		       unsigned int pos, unsigned int count,
  		       const void *kbuf, const void __user *ubuf)
  {
  	int ret;
  
  	ret = init_fpu(target);
  	if (ret)
  		return ret;
  
  	set_stopped_child_used_math(target);
  
  	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,

  				  &target->thread.xstate->hardfpu, 0, -1);

  }
  
  static int fpregs_active(struct task_struct *target,
  			 const struct user_regset *regset)
  {
  	return tsk_used_math(target) ? regset->n : 0;
  }
  #endif

  const struct pt_regs_offset regoffset_table[] = {
  	REG_OFFSET_NAME(pc),
  	REG_OFFSET_NAME(sr),
  	REG_OFFSET_NAME(syscall_nr),
  	REGS_OFFSET_NAME(0),
  	REGS_OFFSET_NAME(1),
  	REGS_OFFSET_NAME(2),
  	REGS_OFFSET_NAME(3),
  	REGS_OFFSET_NAME(4),
  	REGS_OFFSET_NAME(5),
  	REGS_OFFSET_NAME(6),
  	REGS_OFFSET_NAME(7),
  	REGS_OFFSET_NAME(8),
  	REGS_OFFSET_NAME(9),
  	REGS_OFFSET_NAME(10),
  	REGS_OFFSET_NAME(11),
  	REGS_OFFSET_NAME(12),
  	REGS_OFFSET_NAME(13),
  	REGS_OFFSET_NAME(14),
  	REGS_OFFSET_NAME(15),
  	REGS_OFFSET_NAME(16),
  	REGS_OFFSET_NAME(17),
  	REGS_OFFSET_NAME(18),
  	REGS_OFFSET_NAME(19),
  	REGS_OFFSET_NAME(20),
  	REGS_OFFSET_NAME(21),
  	REGS_OFFSET_NAME(22),
  	REGS_OFFSET_NAME(23),
  	REGS_OFFSET_NAME(24),
  	REGS_OFFSET_NAME(25),
  	REGS_OFFSET_NAME(26),
  	REGS_OFFSET_NAME(27),
  	REGS_OFFSET_NAME(28),
  	REGS_OFFSET_NAME(29),
  	REGS_OFFSET_NAME(30),
  	REGS_OFFSET_NAME(31),
  	REGS_OFFSET_NAME(32),
  	REGS_OFFSET_NAME(33),
  	REGS_OFFSET_NAME(34),
  	REGS_OFFSET_NAME(35),
  	REGS_OFFSET_NAME(36),
  	REGS_OFFSET_NAME(37),
  	REGS_OFFSET_NAME(38),
  	REGS_OFFSET_NAME(39),
  	REGS_OFFSET_NAME(40),
  	REGS_OFFSET_NAME(41),
  	REGS_OFFSET_NAME(42),
  	REGS_OFFSET_NAME(43),
  	REGS_OFFSET_NAME(44),
  	REGS_OFFSET_NAME(45),
  	REGS_OFFSET_NAME(46),
  	REGS_OFFSET_NAME(47),
  	REGS_OFFSET_NAME(48),
  	REGS_OFFSET_NAME(49),
  	REGS_OFFSET_NAME(50),
  	REGS_OFFSET_NAME(51),
  	REGS_OFFSET_NAME(52),
  	REGS_OFFSET_NAME(53),
  	REGS_OFFSET_NAME(54),
  	REGS_OFFSET_NAME(55),
  	REGS_OFFSET_NAME(56),
  	REGS_OFFSET_NAME(57),
  	REGS_OFFSET_NAME(58),
  	REGS_OFFSET_NAME(59),
  	REGS_OFFSET_NAME(60),
  	REGS_OFFSET_NAME(61),
  	REGS_OFFSET_NAME(62),
  	REGS_OFFSET_NAME(63),
  	TREGS_OFFSET_NAME(0),
  	TREGS_OFFSET_NAME(1),
  	TREGS_OFFSET_NAME(2),
  	TREGS_OFFSET_NAME(3),
  	TREGS_OFFSET_NAME(4),
  	TREGS_OFFSET_NAME(5),
  	TREGS_OFFSET_NAME(6),
  	TREGS_OFFSET_NAME(7),
  	REG_OFFSET_END,
  };

  /*
   * These are our native regset flavours.
   */
  enum sh_regset {
  	REGSET_GENERAL,
  #ifdef CONFIG_SH_FPU
  	REGSET_FPU,
  #endif
  };
  
  static const struct user_regset sh_regsets[] = {
  	/*
  	 * Format is:
  	 *	PC, SR, SYSCALL,
  	 *	R1 --> R63,
  	 *	TR0 --> TR7,
  	 */
  	[REGSET_GENERAL] = {
  		.core_note_type	= NT_PRSTATUS,
  		.n		= ELF_NGREG,
  		.size		= sizeof(long long),
  		.align		= sizeof(long long),
  		.get		= genregs_get,
  		.set		= genregs_set,
  	},
  
  #ifdef CONFIG_SH_FPU
  	[REGSET_FPU] = {
  		.core_note_type	= NT_PRFPREG,
  		.n		= sizeof(struct user_fpu_struct) /
  				  sizeof(long long),
  		.size		= sizeof(long long),
  		.align		= sizeof(long long),
  		.get		= fpregs_get,
  		.set		= fpregs_set,
  		.active		= fpregs_active,
  	},
  #endif
  };
  
  static const struct user_regset_view user_sh64_native_view = {
  	.name		= "sh64",
  	.e_machine	= EM_SH,
  	.regsets	= sh_regsets,
  	.n		= ARRAY_SIZE(sh_regsets),
  };
  
  const struct user_regset_view *task_user_regset_view(struct task_struct *task)
  {
  	return &user_sh64_native_view;
  }

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

  {

  	int ret;

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

  	switch (request) {

  	/* read the word at location addr in the USER area. */
  	case PTRACE_PEEKUSR: {
  		unsigned long tmp;
  
  		ret = -EIO;
  		if ((addr & 3) || addr < 0)
  			break;
  
  		if (addr < sizeof(struct pt_regs))
  			tmp = get_stack_long(child, addr);
  		else if ((addr >= offsetof(struct user, fpu)) &&
  			 (addr <  offsetof(struct user, u_fpvalid))) {

  			unsigned long index;

  			ret = init_fpu(child);
  			if (ret)
  				break;

  			index = addr - offsetof(struct user, fpu);
  			tmp = get_fpu_long(child, index);

  		} else if (addr == offsetof(struct user, u_fpvalid)) {
  			tmp = !!tsk_used_math(child);
  		} else {
  			break;
  		}

  		ret = put_user(tmp, datap);

  		break;
  	}

  	case PTRACE_POKEUSR:
                  /* write the word at location addr in the USER area. We must
                     disallow any changes to certain SR bits or u_fpvalid, since
                     this could crash the kernel or result in a security
                     loophole. */
  		ret = -EIO;
  		if ((addr & 3) || addr < 0)
  			break;
  
  		if (addr < sizeof(struct pt_regs)) {
  			/* Ignore change of top 32 bits of SR */
  			if (addr == offsetof (struct pt_regs, sr)+4)
  			{
  				ret = 0;
  				break;
  			}
  			/* If lower 32 bits of SR, ignore non-user bits */
  			if (addr == offsetof (struct pt_regs, sr))
  			{
  				long cursr = get_stack_long(child, addr);
  				data &= ~(SR_MASK);
  				data |= (cursr & SR_MASK);
  			}
  			ret = put_stack_long(child, addr, data);
  		}
  		else if ((addr >= offsetof(struct user, fpu)) &&
  			 (addr <  offsetof(struct user, u_fpvalid))) {

  			unsigned long index;

  			ret = init_fpu(child);
  			if (ret)
  				break;

  			index = addr - offsetof(struct user, fpu);
  			ret = put_fpu_long(child, index, data);

  		}
  		break;

  	case PTRACE_GETREGS:
  		return copy_regset_to_user(child, &user_sh64_native_view,
  					   REGSET_GENERAL,
  					   0, sizeof(struct pt_regs),

  					   datap);

  	case PTRACE_SETREGS:
  		return copy_regset_from_user(child, &user_sh64_native_view,
  					     REGSET_GENERAL,
  					     0, sizeof(struct pt_regs),

  					     datap);

  #ifdef CONFIG_SH_FPU
  	case PTRACE_GETFPREGS:
  		return copy_regset_to_user(child, &user_sh64_native_view,
  					   REGSET_FPU,
  					   0, sizeof(struct user_fpu_struct),

  					   datap);

  	case PTRACE_SETFPREGS:
  		return copy_regset_from_user(child, &user_sh64_native_view,
  					     REGSET_FPU,
  					     0, sizeof(struct user_fpu_struct),

  					     datap);

  #endif

  	default:
  		ret = ptrace_request(child, request, addr, data);
  		break;
  	}

  	return ret;
  }

  asmlinkage int sh64_ptrace(long request, long pid,
  			   unsigned long addr, unsigned long data)

  {

  #define WPC_DBRMODE 0x0d104008

  	static unsigned long first_call;

  	if (!test_and_set_bit(0, &first_call)) {

  		/* Set WPC.DBRMODE to 0.  This makes all debug events get
  		 * delivered through RESVEC, i.e. into the handlers in entry.S.
  		 * (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
  		 * would normally be left set to 1, which makes debug events get
  		 * delivered through DBRVEC, i.e. into the remote gdb's
  		 * handlers.  This prevents ptrace getting them, and confuses
  		 * the remote gdb.) */
  		printk("DBRMODE set to 0 to permit native debugging
  ");
  		poke_real_address_q(WPC_DBRMODE, 0);

  	}

  
  	return sys_ptrace(request, pid, addr, data);
  }

  static inline int audit_arch(void)
  {
  	int arch = EM_SH;
  
  #ifdef CONFIG_64BIT
  	arch |= __AUDIT_ARCH_64BIT;
  #endif
  #ifdef CONFIG_CPU_LITTLE_ENDIAN
  	arch |= __AUDIT_ARCH_LE;
  #endif
  
  	return arch;
  }

  asmlinkage long long do_syscall_trace_enter(struct pt_regs *regs)

  {

  	long long ret = 0;

  	secure_computing(regs->regs[9]);

  	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
  	    tracehook_report_syscall_entry(regs))
  		/*
  		 * Tracing decided this syscall should not happen.
  		 * We'll return a bogus call number to get an ENOSYS
  		 * error, but leave the original number in regs->regs[0].
  		 */
  		ret = -1LL;

  	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
  		trace_sys_enter(regs, regs->regs[9]);

  	if (unlikely(current->audit_context))

  		audit_syscall_entry(audit_arch(), regs->regs[1],

  				    regs->regs[2], regs->regs[3],
  				    regs->regs[4], regs->regs[5]);

  
  	return ret ?: regs->regs[9];
  }
  
  asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
  {

  	int step;

  	if (unlikely(current->audit_context))
  		audit_syscall_exit(AUDITSC_RESULT(regs->regs[9]),
  				   regs->regs[9]);

  	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
  		trace_sys_exit(regs, regs->regs[9]);

  	step = test_thread_flag(TIF_SINGLESTEP);
  	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
  		tracehook_report_syscall_exit(regs, step);

  }
  
  /* Called with interrupts disabled */
  asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
  {
  	/* This is called after a single step exception (DEBUGSS).
  	   There is no need to change the PC, as it is a post-execution
  	   exception, as entry.S does not do anything to the PC for DEBUGSS.
  	   We need to clear the Single Step setting in SR to avoid
  	   continually stepping. */
  	local_irq_enable();
  	regs->sr &= ~SR_SSTEP;
  	force_sig(SIGTRAP, current);
  }
  
  /* Called with interrupts disabled */

  BUILD_TRAP_HANDLER(breakpoint)

  {

  	TRAP_HANDLER_DECL;

  	/* We need to forward step the PC, to counteract the backstep done
  	   in signal.c. */
  	local_irq_enable();
  	force_sig(SIGTRAP, current);
  	regs->pc += 4;
  }
  
  /*
   * Called by kernel/ptrace.c when detaching..
   *
   * Make sure single step bits etc are not set.
   */
  void ptrace_disable(struct task_struct *child)
  {

  	user_disable_single_step(child);

  }