path: root/arch/arm26/kernel/ptrace.c

/*
 *  linux/arch/arm26/kernel/ptrace.c
 *
 *  By Ross Biro 1/23/92
 * edited by Linus Torvalds
 * ARM modifications Copyright (C) 2000 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#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/ptrace.h>
#include <linux/user.h>
#include <linux/security.h>
#include <linux/signal.h>

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

#include "ptrace.h"

#define REG_PC	15
#define REG_PSR 15
/*
 * does not yet catch signals sent when the child dies.
 * in exit.c or in signal.c.
 */

/*
 * Breakpoint SWI instruction: SWI &9F0001
 */
#define BREAKINST_ARM	0xef9f0001

/*
 * Get the address of the live pt_regs for the specified task.
 * These are saved onto the top kernel stack when the process
 * is not running.
 *
 * Note: if a user thread is execve'd from kernel space, the
 * kernel stack will not be empty on entry to the kernel, so
 * ptracing these tasks will fail.
 */
static inline struct pt_regs *
get_user_regs(struct task_struct *task)
{
	return __get_user_regs(task->thread_info);
}

/*
 * this routine will get a word off of the processes privileged stack.
 * the offset is how far from the base addr as stored in the THREAD.
 * this routine assumes that all the privileged stacks are in our
 * data space.
 */
static inline long get_user_reg(struct task_struct *task, int offset)
{
	return get_user_regs(task)->uregs[offset];
}

/*
 * this routine will put a word on the processes privileged stack.
 * the offset is how far from the base addr as stored in the THREAD.
 * this routine assumes that all the privileged stacks are in our
 * data space.
 */
static inline int
put_user_reg(struct task_struct *task, int offset, long data)
{
	struct pt_regs newregs, *regs = get_user_regs(task);
	int ret = -EINVAL;

	newregs = *regs;
	newregs.uregs[offset] = data;

	if (valid_user_regs(&newregs)) {
		regs->uregs[offset] = data;
		ret = 0;
	}

	return ret;
}

static inline int
read_u32(struct task_struct *task, unsigned long addr, u32 *res)
{
	int ret;

	ret = access_process_vm(task, addr, res, sizeof(*res), 0);

	return ret == sizeof(*res) ? 0 : -EIO;
}

static inline int
read_instr(struct task_struct *task, unsigned long addr, u32 *res)
{
	int ret;
	u32 val;
	ret = access_process_vm(task, addr & ~3, &val, sizeof(val), 0);
	ret = ret == sizeof(val) ? 0 : -EIO;
	*res = val;
	return ret;
}

/*
 * Get value of register `rn' (in the instruction)
 */
static unsigned long
ptrace_getrn(struct task_struct *child, unsigned long insn)
{
	unsigned int reg = (insn >> 16) & 15;
	unsigned long val;

	val = get_user_reg(child, reg);
	if (reg == 15)
		val = pc_pointer(val + 8); //FIXME - correct for arm26?

	return val;
}

/*
 * Get value of operand 2 (in an ALU instruction)
 */
static unsigned long
ptrace_getaluop2(struct task_struct *child, unsigned long insn)
{
	unsigned long val;
	int shift;
	int type;

	if (insn & 1 << 25) {
		val = insn & 255;
		shift = (insn >> 8) & 15;
		type = 3;
	} else {
		val = get_user_reg (child, insn & 15);

		if (insn & (1 << 4))
			shift = (int)get_user_reg (child, (insn >> 8) & 15);
		else
			shift = (insn >> 7) & 31;

		type = (insn >> 5) & 3;
	}

	switch (type) {
	case 0:	val <<= shift;	break;
	case 1:	val >>= shift;	break;
	case 2:
		val = (((signed long)val) >> shift);
		break;
	case 3:
 		val = (val >> shift) | (val << (32 - shift));
		break;
	}
	return val;
}

/*
 * Get value of operand 2 (in a LDR instruction)
 */
static unsigned long
ptrace_getldrop2(struct task_struct *child, unsigned long insn)
{
	unsigned long val;
	int shift;
	int type;

	val = get_user_reg(child, insn & 15);
	shift = (insn >> 7) & 31;
	type = (insn >> 5) & 3;

	switch (type) {
	case 0:	val <<= shift;	break;
	case 1:	val >>= shift;	break;
	case 2:
		val = (((signed long)val) >> shift);
		break;
	case 3:
 		val = (val >> shift) | (val << (32 - shift));
		break;
	}
	return val;
}

#define OP_MASK	0x01e00000
#define OP_AND	0x00000000
#define OP_EOR	0x00200000
#define OP_SUB	0x00400000
#define OP_RSB	0x00600000
#define OP_ADD	0x00800000
#define OP_ADC	0x00a00000
#define OP_SBC	0x00c00000
#define OP_RSC	0x00e00000
#define OP_ORR	0x01800000
#define OP_MOV	0x01a00000
#define OP_BIC	0x01c00000
#define OP_MVN	0x01e00000

static unsigned long
get_branch_address(struct task_struct *child, unsigned long pc, unsigned long insn)
{
	u32 alt = 0;

	switch (insn & 0x0e000000) {
	case 0x00000000:
	case 0x02000000: {
		/*
		 * data processing
		 */
		long aluop1, aluop2, ccbit;

		if ((insn & 0xf000) != 0xf000)
			break;

		aluop1 = ptrace_getrn(child, insn);
		aluop2 = ptrace_getaluop2(child, insn);
		ccbit  = get_user_reg(child, REG_PSR) & PSR_C_BIT ? 1 : 0;

		switch (insn & OP_MASK)