1/*
  2 *  linux/arch/m68knommu/kernel/ptrace.c
  3 *
  4 *  Copyright (C) 1994 by Hamish Macdonald
  5 *  Taken from linux/kernel/ptrace.c and modified for M680x0.
  6 *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
  7 *
  8 * This file is subject to the terms and conditions of the GNU General
  9 * Public License.  See the file COPYING in the main directory of
 10 * this archive for more details.
 11 */
 12
 13#include <linux/kernel.h>
 14#include <linux/sched.h>
 15#include <linux/mm.h>
 16#include <linux/smp.h>
 17#include <linux/errno.h>
 18#include <linux/ptrace.h>
 19#include <linux/user.h>
 20#include <linux/signal.h>
 21#include <linux/tracehook.h>
 22
 23#include <asm/uaccess.h>
 24#include <asm/page.h>
 25#include <asm/pgtable.h>
 26#include <asm/system.h>
 27#include <asm/processor.h>
 28
 29/*
 30 * does not yet catch signals sent when the child dies.
 31 * in exit.c or in signal.c.
 32 */
 33
 34/* determines which bits in the SR the user has access to. */
 35/* 1 = access 0 = no access */
 36#define SR_MASK 0x001f
 37
 38/* sets the trace bits. */
 39#define TRACE_BITS 0x8000
 40
 41/* Find the stack offset for a register, relative to thread.esp0. */
 42#define PT_REG(reg)	((long)&((struct pt_regs *)0)->reg)
 43#define SW_REG(reg)	((long)&((struct switch_stack *)0)->reg \
 44			 - sizeof(struct switch_stack))
 45/* Mapping from PT_xxx to the stack offset at which the register is
 46   saved.  Notice that usp has no stack-slot and needs to be treated
 47   specially (see get_reg/put_reg below). */
 48static int regoff[] = {
 49	PT_REG(d1), PT_REG(d2), PT_REG(d3), PT_REG(d4),
 50	PT_REG(d5), SW_REG(d6), SW_REG(d7), PT_REG(a0),
 51	PT_REG(a1), PT_REG(a2), SW_REG(a3), SW_REG(a4),
 52	SW_REG(a5), SW_REG(a6), PT_REG(d0), -1,
 53	PT_REG(orig_d0), PT_REG(sr), PT_REG(pc),
 54};
 55
 56/*
 57 * Get contents of register REGNO in task TASK.
 58 */
 59static inline long get_reg(struct task_struct *task, int regno)
 60{
 61	unsigned long *addr;
 62
 63	if (regno == PT_USP)
 64		addr = &task->thread.usp;
 65	else if (regno < ARRAY_SIZE(regoff))
 66		addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
 67	else
 68		return 0;
 69	return *addr;
 70}
 71
 72/*
 73 * Write contents of register REGNO in task TASK.
 74 */
 75static inline int put_reg(struct task_struct *task, int regno,
 76			  unsigned long data)
 77{
 78	unsigned long *addr;
 79
 80	if (regno == PT_USP)
 81		addr = &task->thread.usp;
 82	else if (regno < ARRAY_SIZE(regoff))
 83		addr = (unsigned long *) (task->thread.esp0 + regoff[regno]);
 84	else
 85		return -1;
 86	*addr = data;
 87	return 0;
 88}
 89
 90void user_enable_single_step(struct task_struct *task)
 91{
 92	unsigned long srflags;
 93	srflags = get_reg(task, PT_SR) | (TRACE_BITS << 16);
 94	put_reg(task, PT_SR, srflags);
 95}
 96
 97void user_disable_single_step(struct task_struct *task)
 98{
 99	unsigned long srflags;
100	srflags = get_reg(task, PT_SR) & ~(TRACE_BITS << 16);
101	put_reg(task, PT_SR, srflags);
102}
103
104/*
105 * Called by kernel/ptrace.c when detaching..
106 *
107 * Make sure the single step bit is not set.
108 */
109void ptrace_disable(struct task_struct *child)
110{
111	/* make sure the single step bit is not set. */
112	user_disable_single_step(child);
113}
114
115long arch_ptrace(struct task_struct *child, long request,
116		 unsigned long addr, unsigned long data)
117{
118	int ret;
119	int regno = addr >> 2;
120	unsigned long __user *datap = (unsigned long __user *) data;
121
122	switch (request) {
123		/* read the word at location addr in the USER area. */
124		case PTRACE_PEEKUSR: {
125			unsigned long tmp;
126			
127			ret = -EIO;
128			if ((addr & 3) || addr > sizeof(struct user) - 3)
129				break;
130			
131			tmp = 0;  /* Default return condition */
132			ret = -EIO;
133			if (regno < 19) {
134				tmp = get_reg(child, regno);
135				if (regno == PT_SR)
136					tmp >>= 16;
137			} else if (regno >= 21 && regno < 49) {
138				tmp = child->thread.fp[regno - 21];
139			} else if (regno == 49) {
140				tmp = child->mm->start_code;
141			} else if (regno == 50) {
142				tmp = child->mm->start_data;
143			} else if (regno == 51) {
144				tmp = child->mm->end_code;
145			} else
146				break;
147			ret = put_user(tmp, datap);
148			break;
149		}
150
151		case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
152			ret = -EIO;
153			if ((addr & 3) || addr > sizeof(struct user) - 3)
154				break;
155
156			if (regno == PT_SR) {
157				data &= SR_MASK;
158				data <<= 16;
159				data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
160			}
161			if (regno < 19) {
162				if (put_reg(child, regno, data))
163					break;
164				ret = 0;
165				break;
166			}
167			if (regno >= 21 && regno < 48)
168			{
169				child->thread.fp[regno - 21] = data;
170				ret = 0;
171			}
172			break;
173
174		case PTRACE_GETREGS: { /* Get all gp regs from the child. */
175		  	int i;
176			unsigned long tmp;
177			for (i = 0; i < 19; i++) {
178			    tmp = get_reg(child, i);
179			    if (i == PT_SR)
180				tmp >>= 16;
181			    if (put_user(tmp, datap)) {
182				ret = -EFAULT;
183				break;
184			    }
185			    datap++;
186			}
187			ret = 0;
188			break;
189		}
190
191		case PTRACE_SETREGS: { /* Set all gp regs in the child. */
192			int i;
193			unsigned long tmp;
194			for (i = 0; i < 19; i++) {
195			    if (get_user(tmp, datap)) {
196				ret = -EFAULT;
197				break;
198			    }
199			    if (i == PT_SR) {
200				tmp &= SR_MASK;
201				tmp <<= 16;
202				tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
203			    }
204			    put_reg(child, i, tmp);
205			    datap++;
206			}
207			ret = 0;
208			break;
209		}
210
211#ifdef PTRACE_GETFPREGS
212		case PTRACE_GETFPREGS: { /* Get the child FPU state. */
213			ret = 0;
214			if (copy_to_user(datap, &child->thread.fp,
215					 sizeof(struct user_m68kfp_struct)))
216				ret = -EFAULT;
217			break;
218		}
219#endif
220
221#ifdef PTRACE_SETFPREGS
222		case PTRACE_SETFPREGS: { /* Set the child FPU state. */
223			ret = 0;
224			if (copy_from_user(&child->thread.fp, datap,
225					   sizeof(struct user_m68kfp_struct)))
226				ret = -EFAULT;
227			break;
228		}
229#endif
230
231	case PTRACE_GET_THREAD_AREA:
232		ret = put_user(task_thread_info(child)->tp_value, datap);
233		break;
234
235		default:
236			ret = ptrace_request(child, request, addr, data);
237			break;
238	}
239	return ret;
240}
241
242asmlinkage int syscall_trace_enter(void)
243{
244	int ret = 0;
245
246	if (test_thread_flag(TIF_SYSCALL_TRACE))
247		ret = tracehook_report_syscall_entry(task_pt_regs(current));
248	return ret;
249}
250
251asmlinkage void syscall_trace_leave(void)
252{
253	if (test_thread_flag(TIF_SYSCALL_TRACE))
254		tracehook_report_syscall_exit(task_pt_regs(current), 0);
255}