path: root/arch/m32r/kernel/ptrace.c

/*
 * linux/arch/m32r/kernel/ptrace.c
 *
 * Copyright (C) 2002  Hirokazu Takata, Takeo Takahashi
 * Copyright (C) 2004  Hirokazu Takata, Kei Sakamoto
 *
 * Original x86 implementation:
 *	By Ross Biro 1/23/92
 *	edited by Linus Torvalds
 *
 * Some code taken from sh version:
 *   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
 * Some code taken from arm version:
 *   Copyright (C) 2000 Russell King
 */

#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/string.h>
#include <linux/signal.h>

#include <asm/cacheflush.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>

/*
 * This routine will get a word off of the process kernel stack.
 */
static inline unsigned long int
get_stack_long(struct task_struct *task, int offset)
{
	unsigned long *stack;

	stack = (unsigned long *)task_pt_regs(task);

	return stack[offset];
}

/*
 * This routine will put a word on the process kernel stack.
 */
static inline int
put_stack_long(struct task_struct *task, int offset, unsigned long data)
{
	unsigned long *stack;

	stack = (unsigned long *)task_pt_regs(task);
	stack[offset] = data;

	return 0;
}

static int reg_offset[] = {
	PT_R0, PT_R1, PT_R2, PT_R3, PT_R4, PT_R5, PT_R6, PT_R7,
	PT_R8, PT_R9, PT_R10, PT_R11, PT_R12, PT_FP, PT_LR, PT_SPU,
};

/*
 * Read the word at offset "off" into the "struct user".  We
 * actually access the pt_regs stored on the kernel stack.
 */
static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
			    unsigned long __user *data)
{
	unsigned long tmp;
#ifndef NO_FPU
	struct user * dummy = NULL;
#endif

	if ((off & 3) || (off < 0) || (off > sizeof(struct user) - 3))
		return -EIO;

	off >>= 2;
	switch (off) {
	case PT_EVB:
		__asm__ __volatile__ (
			"mvfc	%0, cr5 \n\t"
	 		: "=r" (tmp)
		);
		break;
	case PT_CBR: {
			unsigned long psw;
			psw = get_stack_long(tsk, PT_PSW);
			tmp = ((psw >> 8) & 1);
		}
		break;
	case PT_PSW: {
			unsigned long psw, bbpsw;
			psw = get_stack_long(tsk, PT_PSW);
			bbpsw = get_stack_long(tsk, PT_BBPSW);
			tmp = ((psw >> 8) & 0xff) | ((bbpsw & 0xff) << 8);
		}
		break;
	case PT_PC:
		tmp = get_stack_long(tsk, PT_BPC);
		break;
	case PT_BPC:
		off = PT_BBPC;
		/* fall through */
	default:
		if (off < (sizeof(struct pt_regs) >> 2))
			tmp = get_stack_long(tsk, off);
#ifndef NO_FPU
		else if (off >= (long)(&dummy->fpu >> 2) &&
			 off < (long)(&dummy->u_fpvalid >> 2)) {
			if (!tsk_used_math(tsk)) {
				if (off == (long)(&dummy->fpu.fpscr >> 2))
					tmp = FPSCR_INIT;
				else
					tmp = 0;
			} else
				tmp = ((long *)(&tsk->thread.fpu >> 2))
					[off - (long)&dummy->fpu];
		} else if (off == (long)(&dummy->u_fpvalid >> 2))
			tmp = !!tsk_used_math(tsk);
#endif /* not NO_FPU */
		else
			tmp = 0;
	}

	return put_user(tmp, data);
}

static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
			     unsigned long data)
{
	int ret = -EIO;
#ifndef NO_FPU
	struct user * dummy = NULL;
#endif

	if ((off & 3) || off < 0 ||
	    off > sizeof(struct user) - 3)
		return -EIO;

	off >>= 2;
	switch (off) {
	case PT_EVB:
	case PT_BPC:
	case PT_SPI:
		/* We don't allow to modify evb. */
		ret = 0;
		break;
	case PT_PSW:
	case PT_CBR: {
			/* We allow to modify only cbr in psw */
			unsigned long psw;
			psw = get_stack_long(tsk, PT_PSW);
			psw = (psw & ~0x100) | ((data & 1) << 8);
			ret = put_stack_long(tsk, PT_PSW, psw);
		}
		break;
	case PT_PC:
		off = PT_BPC;
		data &= ~1;
		/* fall through */
	default:
		if (off < (sizeof(struct pt_regs) >> 2))
			ret = put_stack_long(tsk, off, data);
#ifndef NO_FPU
		else if (off >= (long)(&dummy->fpu >> 2) &&
			 off < (long)(&dummy->u_fpvalid >>