path: root/arch/powerpc/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@samba.org).
 *
 * 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/errno.h>
#include <linux/ptrace.h>
#include <linux/regset.h>
#include <linux/tracehook.h>
#include <linux/elf.h>
#include <linux/user.h>
#include <linux/security.h>
#include <linux/signal.h>
#include <linux/seccomp.h>
#include <linux/audit.h>
#ifdef CONFIG_PPC32
#include <linux/module.h>
#endif

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

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

/*
 * 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

/*
 * Max register writeable via put_reg
 */
#ifdef CONFIG_PPC32
#define PT_MAX_PUT_REG	PT_MQ
#else
#define PT_MAX_PUT_REG	PT_CCR
#endif

static unsigned long get_user_msr(struct task_struct *task)
{
	return task->thread.regs->msr | task->thread.fpexc_mode;
}

static int set_user_msr(struct task_struct *task, unsigned long msr)
{
	task->thread.regs->msr &= ~MSR_DEBUGCHANGE;
	task->thread.regs->msr |= msr & MSR_DEBUGCHANGE;
	return 0;
}

/*
 * We prevent mucking around with the reserved area of trap
 * which are used internally by the kernel.
 */
static int set_user_trap(struct task_struct *task, unsigned long trap)
{
	task->thread.regs->trap = trap & 0xfff0;
	return 0;
}

/*
 * Get contents of register REGNO in task TASK.
 */
unsigned long ptrace_get_reg(struct task_struct *task, int regno)
{
	if (task->thread.regs == NULL)
		return -EIO;

	if (regno == PT_MSR)
		return get_user_msr(task);

	if (regno < (sizeof(struct pt_regs) / sizeof(unsigned long)))
		return ((unsigned long *)task->thread.regs)[regno];

	return -EIO;
}

/*
 * Write contents of register REGNO in task TASK.
 */
int ptrace_put_reg(struct task_struct *task, int regno, unsigned long data)
{
	if (task->thread.regs == NULL)
		return -EIO;

	if (regno == PT_MSR)
		return set_user_msr(task, data);
	if (regno == PT_TRAP)
		return set_user_trap(task, data);

	if (regno <= PT_MAX_PUT_REG) {
		((unsigned long *)task->thread.regs)[regno] = data;
		return 0;
	}
	return -EIO;
}

static int gpr_get(struct task_struct *target, const struct user_regset *regset,
		   unsigned int pos, unsigned int count,
		   void *kbuf, void __user *ubuf)
{
	int ret;

	if (target->thread.regs == NULL)
		return -EIO;

	CHECK_FULL_REGS(target->thread.regs);

	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
				  target->thread.regs,
				  0, offsetof(struct pt_regs, msr));
	if (!ret) {
		unsigned long msr = get_user_msr(target);
		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &msr,
					  offsetof(struct pt_regs, msr),
					  offsetof(struct pt_regs, msr) +
					  sizeof(msr));
	}

	BUILD_BUG_ON(offsetof(struct pt_regs,