arch/ppc/kernel/ptrace.c - third_party/linux - Git at Google

 /*
  *  arch/ppc/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>

 /*
  * Set of msr bits that gdb can change on behalf of a process.
  */
 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
 #define MSR_DEBUGCHANGE	0
 #else
 #define MSR_DEBUGCHANGE	(MSR_SE | MSR_BE)
 #endif

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

 /*
  * Get contents of register REGNO in task TASK.
  */
 static inline unsigned long get_reg(struct task_struct *task, int regno)
 {
 	if (regno < sizeof(struct pt_regs) / sizeof(unsigned long)
 	    && task->thread.regs != NULL)
 		return ((unsigned long *)task->thread.regs)[regno];
 	return (0);
 }

 /*
  * Write contents of register REGNO in task TASK.
  */
 static inline int put_reg(struct task_struct *task, int regno,
 			  unsigned long data)
 {
 	if (regno <= PT_MQ && task->thread.regs != NULL) {
 		if (regno == PT_MSR)
 			data = (data & MSR_DEBUGCHANGE)
 				| (task->thread.regs->msr & ~MSR_DEBUGCHANGE);
 		((unsigned long *)task->thread.regs)[regno] = data;
 		return 0;
 	}
 	return -EIO;
 }

 #ifdef CONFIG_ALTIVEC
 /*
  * Get contents of AltiVec register state in task TASK
  */
 static inline int get_vrregs(unsigned long __user *data, struct task_struct *task)
 {
 	int i, j;

 	if (!access_ok(VERIFY_WRITE, data, 133 * sizeof(unsigned long)))
 		return -EFAULT;

 	/* copy AltiVec registers VR[0] .. VR[31] */
 	for (i = 0; i < 32; i++)
 		for (j = 0; j < 4; j++, data++)
 			if (__put_user(task->thread.vr[i].u[j], data))
 				return -EFAULT;

 	/* copy VSCR */
 	for (i = 0; i < 4; i++, data++)
 		if (__put_user(task->thread.vscr.u[i], data))
 			return -EFAULT;

         /* copy VRSAVE */
 	if (__put_user(task->thread.vrsave, data))
 		return -EFAULT;

 	return 0;
 }

 /*
  * Write contents of AltiVec register state into task TASK.
  */
 static inline int set_vrregs(struct task_struct *task, unsigned long __user *data)
 {
 	int i, j;

 	if (!access_ok(VERIFY_READ, data, 133 * sizeof(unsigned long)))
 		return -EFAULT;

 	/* copy AltiVec registers VR[0] .. VR[31] */
 	for (i = 0; i < 32; i++)
 		for (j = 0; j < 4; j++, data++)
 			if (__get_user(task->thread.vr[i].u[j], data))
 				return -EFAULT;

 	/* copy VSCR */
 	for (i = 0; i < 4; i++, data++)
 		if (__get_user(task->thread.vscr.u[i], data))
 			return -EFAULT;

 	/* copy VRSAVE */
 	if (__get_user(task->thread.vrsave, data))
 		return -EFAULT;

 	return 0;
 }
 #endif

 #ifdef CONFIG_SPE

 /*
  * For get_evrregs/set_evrregs functions 'data' has the following layout:
  *
  * struct {
  *   u32 evr[32];
  *   u64 acc;
  *   u32 spefscr;
  * }
  */

 /*
  * Get contents of SPE register state in task TASK.
  */
 static inline int get_evrregs(unsigned long *data, struct task_struct *task)
 {
 	int i;

 	if (!access_ok(VERIFY_WRITE, data, 35 * sizeof(unsigned long)))
 		return -EFAULT;

 	/* copy SPEFSCR */
 	if (__put_user(task->thread.spefscr, &data[34]))
 		return -EFAULT;

 	/* copy SPE registers EVR[0] .. EVR[31] */
 	for (i = 0; i < 32; i++, data++)
 		if (__put_user(task->thread.evr[i], data))
 			return -EFAULT;

 	/* copy ACC */
 	if (__put_user64(task->thread.acc, (unsigned long long *)data))
 		return -EFAULT;

 	return 0;
 }

 /*
  * Write contents of SPE register state into task TASK.
  */
 static inline int set_evrregs(struct task_struct *task, unsigned long *data)
 {
 	int i;

 	if (!access_ok(VERIFY_READ, data, 35 * sizeof(unsigned long)))
 		return -EFAULT;

 	/* copy SPEFSCR */
 	if (__get_user(task->thread.spefscr, &data[34]))
 		return -EFAULT;

 	/* copy SPE registers EVR[0] .. EVR[31] */
 	for (i = 0; i < 32; i++, data++)
 		if (__get_user(task->thread.evr[i], data))
 			return -EFAULT;
 	/* copy ACC */
 	if (__get_user64(task->thread.acc, (unsigned long long*)data))
 		return -EFAULT;

 	return 0;
 }
 #endif /* CONFIG_SPE */

 static inline void
 set_single_step(struct task_struct *task)
 {
 	struct pt_regs *regs = task->thread.regs;

 	if (regs != NULL) {
 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
 		task->thread.dbcr0 = DBCR0_IDM | DBCR0_IC;
 		regs->msr |= MSR_DE;
 #else
 		regs->msr |= MSR_SE;
 #endif
 	}
 }

 static inline void
 clear_single_step(struct task_struct *task)
 {
 	struct pt_regs *regs = task->thread.regs;

 	if (regs != NULL) {
 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
 		task->thread.dbcr0 = 0;
 		regs->msr &= ~MSR_DE;
 #else
 		regs->msr &= ~MSR_SE;
 #endif
 	}
 }

 /*
  * 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_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 __user *) data);
 		break;
 	}

 	/* read the word at location addr in the USER area. */
 	/* XXX this will need fixing for 64-bit */
 	case PTRACE_PEEKUSR: {
 		unsigned long index, tmp;

 		ret = -EIO;
 		/* convert to index and check */
 		index = (unsigned long) addr >> 2;
 		if ((addr & 3) || index > PT_FPSCR
 		    || child->thread.regs == NULL)
 			break;

 		CHECK_FULL_REGS(child->thread.regs);
 		if (index < PT_FPR0) {
 			tmp = get_reg(child, (int) index);
 		} else {
 			preempt_disable();
 			if (child->thread.regs->msr & MSR_FP)
 				giveup_fpu(child);
 			preempt_enable();
 			tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
 		}
 		ret = put_user(tmp,(unsigned long __user *) 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 >> 2;
 		if ((addr & 3) || index > PT_FPSCR
 		    || child->thread.regs == NULL)
 			break;

 		CHECK_FULL_REGS(child->thread.regs);
 		if (index == PT_ORIG_R3)
 			break;
 		if (index < PT_FPR0) {
 			ret = put_reg(child, index, data);
 		} else {
 			preempt_disable();
 			if (child->thread.regs->msr & MSR_FP)
 				giveup_fpu(child);
 			preempt_enable();
 			((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->exit_state == EXIT_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;

 #ifdef CONFIG_ALTIVEC
 	case PTRACE_GETVRREGS:
 		/* Get the child altivec register state. */
 		preempt_disable();
 		if (child->thread.regs->msr & MSR_VEC)
 			giveup_altivec(child);
 		preempt_enable();
 		ret = get_vrregs((unsigned long __user *)data, child);
 		break;

 	case PTRACE_SETVRREGS:
 		/* Set the child altivec register state. */
 		/* this is to clear the MSR_VEC bit to force a reload
 		 * of register state from memory */
 		preempt_disable();
 		if (child->thread.regs->msr & MSR_VEC)
 			giveup_altivec(child);
 		preempt_enable();
 		ret = set_vrregs(child, (unsigned long __user *)data);
 		break;
 #endif
 #ifdef CONFIG_SPE
 	case PTRACE_GETEVRREGS:
 		/* Get the child spe register state. */
 		if (child->thread.regs->msr & MSR_SPE)
 			giveup_spe(child);
 		ret = get_evrregs((unsigned long __user *)data, child);
 		break;

 	case PTRACE_SETEVRREGS:
 		/* Set the child spe register state. */
 		/* this is to clear the MSR_SPE bit to force a reload
 		 * of register state from memory */
 		if (child->thread.regs->msr & MSR_SPE)
 			giveup_spe(child);
 		ret = set_evrregs(child, (unsigned long __user *)data);
 		break;
 #endif

 	default:
 		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 out_tsk:
 	put_task_struct(child);
 out:
 	unlock_kernel();
 	return ret;
 }

 void do_syscall_trace(void)
 {
         if (!test_thread_flag(TIF_SYSCALL_TRACE)
 	    || !(current->ptrace & PT_PTRACED))
 		return;
 	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;
 	}
 }
	/*
	* arch/ppc/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>

	/*
	* Set of msr bits that gdb can change on behalf of a process.
	*/
	#if defined(CONFIG_40x) \|\| defined(CONFIG_BOOKE)
	#define MSR_DEBUGCHANGE 0
	#else
	#define MSR_DEBUGCHANGE (MSR_SE \| MSR_BE)
	#endif

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

	/*
	* Get contents of register REGNO in task TASK.
	*/
	static inline unsigned long get_reg(struct task_struct *task, int regno)
	{
	if (regno < sizeof(struct pt_regs) / sizeof(unsigned long)
	&& task->thread.regs != NULL)
	return ((unsigned long *)task->thread.regs)[regno];
	return (0);
	}

	/*
	* Write contents of register REGNO in task TASK.
	*/
	static inline int put_reg(struct task_struct *task, int regno,
	unsigned long data)
	{
	if (regno <= PT_MQ && task->thread.regs != NULL) {
	if (regno == PT_MSR)
	data = (data & MSR_DEBUGCHANGE)
	\| (task->thread.regs->msr & ~MSR_DEBUGCHANGE);
	((unsigned long *)task->thread.regs)[regno] = data;
	return 0;
	}
	return -EIO;
	}

	#ifdef CONFIG_ALTIVEC
	/*
	* Get contents of AltiVec register state in task TASK
	*/
	static inline int get_vrregs(unsigned long __user data, struct task_struct task)
	{
	int i, j;

	if (!access_ok(VERIFY_WRITE, data, 133 * sizeof(unsigned long)))
	return -EFAULT;

	/* copy AltiVec registers VR[0] .. VR[31] */
	for (i = 0; i < 32; i++)
	for (j = 0; j < 4; j++, data++)
	if (__put_user(task->thread.vr[i].u[j], data))
	return -EFAULT;

	/* copy VSCR */
	for (i = 0; i < 4; i++, data++)
	if (__put_user(task->thread.vscr.u[i], data))
	return -EFAULT;

	/* copy VRSAVE */
	if (__put_user(task->thread.vrsave, data))
	return -EFAULT;

	return 0;
	}

	/*
	* Write contents of AltiVec register state into task TASK.
	*/
	static inline int set_vrregs(struct task_struct task, unsigned long __user data)
	{
	int i, j;

	if (!access_ok(VERIFY_READ, data, 133 * sizeof(unsigned long)))
	return -EFAULT;

	/* copy AltiVec registers VR[0] .. VR[31] */
	for (i = 0; i < 32; i++)
	for (j = 0; j < 4; j++, data++)
	if (__get_user(task->thread.vr[i].u[j], data))
	return -EFAULT;

	/* copy VSCR */
	for (i = 0; i < 4; i++, data++)
	if (__get_user(task->thread.vscr.u[i], data))
	return -EFAULT;

	/* copy VRSAVE */
	if (__get_user(task->thread.vrsave, data))
	return -EFAULT;

	return 0;
	}
	#endif

	#ifdef CONFIG_SPE

	/*
	* For get_evrregs/set_evrregs functions 'data' has the following layout:
	*
	* struct {
	* u32 evr[32];
	* u64 acc;
	* u32 spefscr;
	* }
	*/

	/*
	* Get contents of SPE register state in task TASK.
	*/
	static inline int get_evrregs(unsigned long data, struct task_struct task)
	{
	int i;

	if (!access_ok(VERIFY_WRITE, data, 35 * sizeof(unsigned long)))
	return -EFAULT;

	/* copy SPEFSCR */
	if (__put_user(task->thread.spefscr, &data[34]))
	return -EFAULT;

	/* copy SPE registers EVR[0] .. EVR[31] */
	for (i = 0; i < 32; i++, data++)
	if (__put_user(task->thread.evr[i], data))
	return -EFAULT;

	/* copy ACC */
	if (__put_user64(task->thread.acc, (unsigned long long *)data))
	return -EFAULT;

	return 0;
	}

	/*
	* Write contents of SPE register state into task TASK.
	*/
	static inline int set_evrregs(struct task_struct task, unsigned long data)
	{
	int i;

	if (!access_ok(VERIFY_READ, data, 35 * sizeof(unsigned long)))
	return -EFAULT;

	/* copy SPEFSCR */
	if (__get_user(task->thread.spefscr, &data[34]))
	return -EFAULT;

	/* copy SPE registers EVR[0] .. EVR[31] */
	for (i = 0; i < 32; i++, data++)
	if (__get_user(task->thread.evr[i], data))
	return -EFAULT;
	/* copy ACC */
	if (__get_user64(task->thread.acc, (unsigned long long*)data))
	return -EFAULT;

	return 0;
	}
	#endif /* CONFIG_SPE */

	static inline void
	set_single_step(struct task_struct *task)
	{
	struct pt_regs *regs = task->thread.regs;

	if (regs != NULL) {
	#if defined(CONFIG_40x) \|\| defined(CONFIG_BOOKE)
	task->thread.dbcr0 = DBCR0_IDM \| DBCR0_IC;
	regs->msr \|= MSR_DE;
	#else
	regs->msr \|= MSR_SE;
	#endif
	}
	}

	static inline void
	clear_single_step(struct task_struct *task)
	{
	struct pt_regs *regs = task->thread.regs;

	if (regs != NULL) {
	#if defined(CONFIG_40x) \|\| defined(CONFIG_BOOKE)
	task->thread.dbcr0 = 0;
	regs->msr &= ~MSR_DE;
	#else
	regs->msr &= ~MSR_SE;
	#endif
	}
	}

	/*
	* 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_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 __user *) data);
	break;
	}

	/* read the word at location addr in the USER area. */
	/* XXX this will need fixing for 64-bit */
	case PTRACE_PEEKUSR: {
	unsigned long index, tmp;

	ret = -EIO;
	/* convert to index and check */
	index = (unsigned long) addr >> 2;
	if ((addr & 3) \|\| index > PT_FPSCR
	\|\| child->thread.regs == NULL)
	break;

	CHECK_FULL_REGS(child->thread.regs);
	if (index < PT_FPR0) {
	tmp = get_reg(child, (int) index);
	} else {
	preempt_disable();
	if (child->thread.regs->msr & MSR_FP)
	giveup_fpu(child);
	preempt_enable();
	tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
	}
	ret = put_user(tmp,(unsigned long __user *) 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 >> 2;
	if ((addr & 3) \|\| index > PT_FPSCR
	\|\| child->thread.regs == NULL)
	break;

	CHECK_FULL_REGS(child->thread.regs);
	if (index == PT_ORIG_R3)
	break;
	if (index < PT_FPR0) {
	ret = put_reg(child, index, data);
	} else {
	preempt_disable();
	if (child->thread.regs->msr & MSR_FP)
	giveup_fpu(child);
	preempt_enable();
	((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->exit_state == EXIT_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;

	#ifdef CONFIG_ALTIVEC
	case PTRACE_GETVRREGS:
	/* Get the child altivec register state. */
	preempt_disable();
	if (child->thread.regs->msr & MSR_VEC)
	giveup_altivec(child);
	preempt_enable();
	ret = get_vrregs((unsigned long __user *)data, child);
	break;

	case PTRACE_SETVRREGS:
	/* Set the child altivec register state. */
	/* this is to clear the MSR_VEC bit to force a reload
	* of register state from memory */
	preempt_disable();
	if (child->thread.regs->msr & MSR_VEC)
	giveup_altivec(child);
	preempt_enable();
	ret = set_vrregs(child, (unsigned long __user *)data);
	break;
	#endif
	#ifdef CONFIG_SPE
	case PTRACE_GETEVRREGS:
	/* Get the child spe register state. */
	if (child->thread.regs->msr & MSR_SPE)
	giveup_spe(child);
	ret = get_evrregs((unsigned long __user *)data, child);
	break;

	case PTRACE_SETEVRREGS:
	/* Set the child spe register state. */
	/* this is to clear the MSR_SPE bit to force a reload
	* of register state from memory */
	if (child->thread.regs->msr & MSR_SPE)
	giveup_spe(child);
	ret = set_evrregs(child, (unsigned long __user *)data);
	break;
	#endif

	default:
	ret = ptrace_request(child, request, addr, data);
	break;
	}
	out_tsk:
	put_task_struct(child);
	out:
	unlock_kernel();
	return ret;
	}

	void do_syscall_trace(void)
	{
	if (!test_thread_flag(TIF_SYSCALL_TRACE)
	\|\| !(current->ptrace & PT_PTRACED))
	return;
	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;
	}
	}