/*
 *  linux/arch/ppc64/kernel/ptrace.c
 *
 *  PowerPC version
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Derived from "arch/m68k/kernel/ptrace.c"
 *  Copyright (C) 1994 by Hamish Macdonald
 *  Taken from linux/kernel/ptrace.c and modified for M680x0.
 *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
 *
 * Modified by Cort Dougan (cort@hq.fsmlabs.com)
 * and Paul Mackerras (paulus@linuxcare.com.au).
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License.  See the file README.legal in the main directory of
 * this archive for more details.
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/security.h>

#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/ptrace-common.h>

/*
 * does not yet catch signals sent when the child dies.
 * in exit.c or in signal.c.
 */

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Make sure single step bits etc are not set.
 */
void ptrace_disable(struct task_struct *child)
{
	/* make sure the single step bit is not set. */
	clear_single_step(child);
}

int sys_ptrace(long request, long pid, long addr, long data)
{
	struct task_struct *child;
	int ret = -EPERM;

	lock_kernel();
	if (request == PTRACE_TRACEME) {
		/* are we already being traced? */
		if (current->ptrace & PT_PTRACED)
			goto out;
		ret = security_ops->ptrace(current->parent, current);
		if (ret)
			goto out;
		/* set the ptrace bit in the process flags. */
		current->ptrace |= PT_PTRACED;
		ret = 0;
		goto out;
	}
	ret = -ESRCH;
	read_lock(&tasklist_lock);
	child = find_task_by_pid(pid);
	if (child)
		get_task_struct(child);
	read_unlock(&tasklist_lock);
	if (!child)
		goto out;

	ret = -EPERM;
	if (pid == 1)		/* you may not mess with init */
		goto out_tsk;

	if (request == PTRACE_ATTACH) {
		ret = ptrace_attach(child);
		goto out_tsk;
	}

	ret = ptrace_check_attach(child, request == PTRACE_KILL);
	if (ret < 0)
		goto out_tsk;

	switch (request) {
	/* when I and D space are separate, these will need to be fixed. */
	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
	case PTRACE_PEEKDATA: {
		unsigned long tmp;
		int copied;

		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
		ret = -EIO;
		if (copied != sizeof(tmp))
			break;
		ret = put_user(tmp,(unsigned long *) data);
		break;
	}

	/* read the word at location addr in the USER area. */
	case PTRACE_PEEKUSR: {
		unsigned long index;
		unsigned long tmp;

		ret = -EIO;
		/* convert to index and check */
		index = (unsigned long) addr >> 3;
		if ((addr & 7) || (index > PT_FPSCR))
			break;

		if (index < PT_FPR0) {
			tmp = get_reg(child, (int)index);
		} else {
			if (child->thread.regs->msr & MSR_FP)
				giveup_fpu(child);
			tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
		}
		ret = put_user(tmp,(unsigned long *) data);
		break;
	}

	/* If I and D space are separate, this will have to be fixed. */
	case PTRACE_POKETEXT: /* write the word at location addr. */
	case PTRACE_POKEDATA:
		ret = 0;
		if (access_process_vm(child, addr, &data, sizeof(data), 1)
				== sizeof(data))
			break;
		ret = -EIO;
		break;

	/* write the word at location addr in the USER area */
	case PTRACE_POKEUSR: {
		unsigned long index;

		ret = -EIO;
		/* convert to index and check */
		index = (unsigned long) addr >> 3;
		if ((addr & 7) || (index > PT_FPSCR))
			break;

		if (index == PT_ORIG_R3)
			break;
		if (index < PT_FPR0) {
			ret = put_reg(child, index, data);
		} else {
			if (child->thread.regs->msr & MSR_FP)
				giveup_fpu(child);
			((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
			ret = 0;
		}
		break;
	}

	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
	case PTRACE_CONT: { /* restart after signal. */
		ret = -EIO;
		if ((unsigned long) data > _NSIG)
			break;
		if (request == PTRACE_SYSCALL)
			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		else
			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		child->exit_code = data;
		/* make sure the single step bit is not set. */
		clear_single_step(child);
		wake_up_process(child);
		ret = 0;
		break;
	}

	/*
	 * make the child exit.  Best I can do is send it a sigkill.
	 * perhaps it should be put in the status that it wants to
	 * exit.
	 */
	case PTRACE_KILL: {
		ret = 0;
		if (child->state == TASK_ZOMBIE)	/* already dead */
			break;
		child->exit_code = SIGKILL;
		/* make sure the single step bit is not set. */
		clear_single_step(child);
		wake_up_process(child);
		break;
	}

	case PTRACE_SINGLESTEP: {  /* set the trap flag. */
		ret = -EIO;
		if ((unsigned long) data > _NSIG)
			break;
		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		set_single_step(child);
		child->exit_code = data;
		/* give it a chance to run. */
		wake_up_process(child);
		ret = 0;
		break;
	}

	case PTRACE_DETACH:
		ret = ptrace_detach(child, data);
		break;

	case PPC_PTRACE_GETREGS: { /* Get GPRs 0 - 31. */
		u64 tmp;
		u64 cntr;

		ret = 0; 
		for (cntr=0; cntr<32 && ret==0; ++cntr) {
			tmp = ((u64*)child->thread.regs)[cntr];
			ret = put_user(tmp, (u64*)(data+cntr));
		}
		break;
	}

	case PPC_PTRACE_SETREGS: { /* Set GPRs 0 - 31. */
		u64 cntr;

		ret = 0; 
		for (cntr=0; cntr<32 && ret==0; ++cntr)
			ret = put_reg(child, cntr, *(u64*)(data+cntr));
		break;
	}

	case PPC_PTRACE_GETFPREGS: { /* Get FPRs 0 - 31. */
		u64 tmp;
		u64 cntr;

		ret = -EIO;
		if (child->thread.regs->msr & MSR_FP)
			giveup_fpu(child);
		ret = 0; 
		for (cntr=0; cntr<32 && ret==0; ++cntr) {
			tmp = ((u64*)child->thread.fpr)[cntr];
			ret = put_user(tmp, (u64*)(data+cntr));
		}
		break;
	}

	case PPC_PTRACE_SETFPREGS: { /* Get FPRs 0 - 31. */
		u64 cntr;

		ret = -EIO;
		if (child->thread.regs->msr & MSR_FP)
			giveup_fpu(child);
		for (cntr=0; cntr<32; ++cntr)
			((u64*)child->thread.fpr)[cntr] = *(u64*)(data+cntr);
		ret = 0; 
		break;
	}

	default:
		ret = -EIO;
		break;
	}
out_tsk:
	put_task_struct(child);
out:
	unlock_kernel();
	return ret;
}

void do_syscall_trace(void)
{
	if (!test_thread_flag(TIF_SYSCALL_TRACE))
		return;
	if (!(current->ptrace & PT_PTRACED))
		return;
	current->exit_code = SIGTRAP;
	current->state = TASK_STOPPED;
	notify_parent(current, SIGCHLD);
	schedule();
	/*
	 * 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;
	}
}
