linux/arch/powerpc/kernel/ptrace32.c

/*
 * ptrace for 32-bit processes running on a 64-bit kernel.
 *
 *  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@samba.org).
 *
 * 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/config.h>
#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 <linux/signal.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.
 */

long compat_sys_ptrace(int request, int pid, unsigned long addr,
		       unsigned 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 int tmp;
		int copied;

		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
		ret = -EIO;
		if (copied != sizeof(tmp))
			break;
		ret = put_user(tmp, (u32 __user *)data);
		break;
	}

	/*
	 * Read 4 bytes of the other process' storage
	 *  data is a pointer specifying where the user wants the
	 *	4 bytes copied into
	 *  addr is a pointer in the user's storage that contains an 8 byte
	 *	address in the other process of the 4 bytes that is to be read
	 * (this is run in a 32-bit process looking at a 64-bit process)
	 * when I and D space are separate, these will need to be fixed.
	 */
	case PPC_PTRACE_PEEKTEXT_3264:
	case PPC_PTRACE_PEEKDATA_3264: {
		u32 tmp;
		int copied;
		u32 __user * addrOthers;

		ret = -EIO;

		/* Get the addr in the other process that we want to read */
		if (get_user(addrOthers, (u32 __user * __user *)addr) != 0)
			break;

		copied = access_process_vm(child, (u64)addrOthers, &tmp,
				sizeof(tmp), 0);
		if (copied != sizeof(tmp))
			break;
		ret = put_user(tmp, (u32 __user *)data);
		break;
	}

	/* Read a register (specified by ADDR) out of the "user area" */
	case PTRACE_PEEKUSR: {
		int index;
		unsigned long tmp;

		ret = -EIO;
		/* convert to index and check */
		index = (unsigned long) addr >> 2;
		if ((addr & 3) || (index > PT_FPSCR32))
			break;

		if (index < PT_FPR0) {
			tmp = get_reg(child, index);
		} else {
			flush_fp_to_thread(child);
			/*
			 * the user space code considers the floating point
			 * to be an array of unsigned int (32 bits) - the
			 * index passed in is based on this assumption.
			 */
			tmp = ((unsigned int *)child->thread.fpr)[index - PT_FPR0];
		}
		ret = put_user((unsigned int)tmp, (u32 __user *)data);
		break;
	}
  
	/*
	 * Read 4 bytes out of the other process' pt_regs area
	 *  data is a pointer specifying where the user wants the
	 *	4 bytes copied into
	 *  addr is the offset into the other process' pt_regs structure
	 *	that is to be read
	 * (this is run in a 32-bit process looking at a 64-bit process)
	 */
	case PPC_PTRACE_PEEKUSR_3264: {
		u32 index;
		u32 reg32bits;
		u64 tmp;
		u32 numReg;
		u32 part;

		ret = -EIO;
		/* Determine which register the user wants */
		index = (u64)addr >> 2;
		numReg = index / 2;
		/* Determine which part of the register the user wants */
		if (index % 2)
			part = 1;  /* want the 2nd half of the register (right-most). */
		else
			part = 0;  /* want the 1st half of the register (left-most). */

		/* Validate the input - check to see if address is on the wrong boundary or beyond the end of the user area */
		if ((addr & 3) || numReg > PT_FPSCR)
			break;

		if (numReg >= PT_FPR0) {
			flush_fp_to_thread(child);
			tmp = ((unsigned long int *)child->thread.fpr)[numReg - PT_FPR0];
		} else { /* register within PT_REGS struct */
			tmp = get_reg(child, numReg);
		} 
		reg32bits = ((u32*)&tmp)[part];
		ret = put_user(reg32bits, (u32 __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: {
		unsigned int tmp;
		tmp = data;
		ret = 0;
		if (access_process_vm(child, addr, &tmp, sizeof(tmp), 1)
				== sizeof(tmp))
			break;
		ret = -EIO;
		break;
	}

	/*
	 * Write 4 bytes into the other process' storage
	 *  data is the 4 bytes that the user wants written
	 *  addr is a pointer in the user's storage that contains an
	 *	8 byte address in the other process where the 4 bytes
	 *	that is to be written
	 * (this is run in a 32-bit process looking at a 64-bit process)
	 * when I and D space are separate, these will need to be fixed.
	 */
	case PPC_PTRACE_POKETEXT_3264:
	case PPC_PTRACE_POKEDATA_3264: {
		u32 tmp = data;
		u32 __user * addrOthers;

		/* Get the addr in the other process that we want to write into */
		ret = -EIO;
		if (get_user(addrOthers, (u32 __user * __user *)addr) != 0)
			break;
		ret = 0;
		if (access_process_vm(child, (u64)addrOthers, &tmp,
					sizeof(tmp), 1) == sizeof(tmp))
			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_FPSCR32))
			break;

		if (index == PT_ORIG_R3)
			break;
		if (index < PT_FPR0) {
			ret = put_reg(child, index, data);
		} else {
			flush_fp_to_thread(child);
			/*
			 * the user space code considers the floating point
			 * to be an array of unsigned int (32 bits) - the
			 * index passed in is based on this assumption.
			 */
			((unsigned int *)child->thread.fpr)[index - PT_FPR0] = data;
			ret = 0;
		}
		break;
	}

	/*
	 * Write 4 bytes into the other process' pt_regs area
	 *  data is the 4 bytes that the user wants written
	 *  addr is the offset into the other process' pt_regs structure
	 *	that is to be written into
	 * (this is run in a 32-bit process looking at a 64-bit process)
	 */
	case PPC_PTRACE_POKEUSR_3264: {
		u32 index;
		u32 numReg;

		ret = -EIO;
		/* Determine which register the user wants */
		index = (u64)addr >> 2;
		numReg = index / 2;
		/*
		 * Validate the input - check to see if address is on the
		 * wrong boundary or beyond the end of the user area
		 */
		if ((addr & 3) || (numReg > PT_FPSCR))
			break;
		/* Insure it is a register we let them change */
		if ((numReg == PT_ORIG_R3)
				|| ((numReg > PT_CCR) && (numReg < PT_FPR0)))
			break;
		if (numReg >= PT_FPR0) {
			flush_fp_to_thread(child);
		}
		if (numReg == PT_MSR)
			data = (data & MSR_DEBUGCHANGE)
				| (child->thread.regs->msr & ~MSR_DEBUGCHANGE);
		((u32*)child->thread.regs)[index] = data;
		ret = 0;
		break;
	}

	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
	case PTRACE_CONT: { /* restart after signal. */
		ret = -EIO;
		if (!valid_signal(data))
			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 (!valid_signal(data))
			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_GET_DEBUGREG: {
		ret = -EINVAL;
		/* We only support one DABR and no IABRS at the moment */
		if (addr > 0)
			break;
		ret = put_user(child->thread.dabr, (u32 __user *)data);
		break;
	}

	case PTRACE_SET_DEBUGREG:
		ret = ptrace_set_debugreg(child, addr, data);
		break;

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

	case PPC_PTRACE_GETREGS: { /* Get GPRs 0 - 31. */
		int i;
		unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
		unsigned int __user *tmp = (unsigned int __user *)addr;

		for (i = 0; i < 32; i++) {
			ret = put_user(*reg, tmp);
			if (ret)
				break;
			reg++;
			tmp++;
		}
		break;
	}

	case PPC_PTRACE_SETREGS: { /* Set GPRs 0 - 31. */
		int i;
		unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
		unsigned int __user *tmp = (unsigned int __user *)addr;

		for (i = 0; i < 32; i++) {
			ret = get_user(*reg, tmp);
			if (ret)
				break;
			reg++;
			tmp++;
		}
		break;
	}

	case PPC_PTRACE_GETFPREGS: { /* Get FPRs 0 - 31. */
		int i;
		unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
		unsigned int __user *tmp = (unsigned int __user *)addr;

		flush_fp_to_thread(child);

		for (i = 0; i < 32; i++) {
			ret = put_user(*reg, tmp);
			if (ret)
				break;
			reg++;
			tmp++;
		}
		break;
	}

	case PPC_PTRACE_SETFPREGS: { /* Get FPRs 0 - 31. */
		int i;
		unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
		unsigned int __user *tmp = (unsigned int __user *)addr;

		flush_fp_to_thread(child);

		for (i = 0; i < 32; i++) {
			ret = get_user(*reg, tmp);
			if (ret)
				break;
			reg++;
			tmp++;
		}
		break;
	}

	case PTRACE_GETEVENTMSG:
		ret = put_user(child->ptrace_message, (unsigned int __user *) data);
		break;

#ifdef CONFIG_ALTIVEC
	case PTRACE_GETVRREGS:
		/* Get the child altivec register state. */
		flush_altivec_to_thread(child);
		ret = get_vrregs((unsigned long __user *)data, child);
		break;

	case PTRACE_SETVRREGS:
		/* Set the child altivec register state. */
		flush_altivec_to_thread(child);
		ret = set_vrregs(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;
}