1 /*
2  *  linux/arch/m68k/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/sched/task_stack.h>
16 #include <linux/mm.h>
17 #include <linux/smp.h>
18 #include <linux/errno.h>
19 #include <linux/ptrace.h>
20 #include <linux/user.h>
21 #include <linux/signal.h>
22 #include <linux/tracehook.h>
23 
24 #include <linux/uaccess.h>
25 #include <asm/page.h>
26 #include <asm/processor.h>
27 
28 /*
29  * does not yet catch signals sent when the child dies.
30  * in exit.c or in signal.c.
31  */
32 
33 /* determines which bits in the SR the user has access to. */
34 /* 1 = access 0 = no access */
35 #define SR_MASK 0x001f
36 
37 /* sets the trace bits. */
38 #define TRACE_BITS 0xC000
39 #define T1_BIT 0x8000
40 #define T0_BIT 0x4000
41 
42 /* Find the stack offset for a register, relative to thread.esp0. */
43 #define PT_REG(reg)	((long)&((struct pt_regs *)0)->reg)
44 #define SW_REG(reg)	((long)&((struct switch_stack *)0)->reg \
45 			 - sizeof(struct switch_stack))
46 /* Mapping from PT_xxx to the stack offset at which the register is
47    saved.  Notice that usp has no stack-slot and needs to be treated
48    specially (see get_reg/put_reg below). */
49 static const int regoff[] = {
50 	[0]	= PT_REG(d1),
51 	[1]	= PT_REG(d2),
52 	[2]	= PT_REG(d3),
53 	[3]	= PT_REG(d4),
54 	[4]	= PT_REG(d5),
55 	[5]	= SW_REG(d6),
56 	[6]	= SW_REG(d7),
57 	[7]	= PT_REG(a0),
58 	[8]	= PT_REG(a1),
59 	[9]	= PT_REG(a2),
60 	[10]	= SW_REG(a3),
61 	[11]	= SW_REG(a4),
62 	[12]	= SW_REG(a5),
63 	[13]	= SW_REG(a6),
64 	[14]	= PT_REG(d0),
65 	[15]	= -1,
66 	[16]	= PT_REG(orig_d0),
67 	[17]	= PT_REG(sr),
68 	[18]	= PT_REG(pc),
69 };
70 
71 /*
72  * Get contents of register REGNO in task TASK.
73  */
get_reg(struct task_struct * task,int regno)74 static inline long get_reg(struct task_struct *task, int regno)
75 {
76 	unsigned long *addr;
77 
78 	if (regno == PT_USP)
79 		addr = &task->thread.usp;
80 	else if (regno < ARRAY_SIZE(regoff))
81 		addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
82 	else
83 		return 0;
84 	/* Need to take stkadj into account. */
85 	if (regno == PT_SR || regno == PT_PC) {
86 		long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj));
87 		addr = (unsigned long *) ((unsigned long)addr + stkadj);
88 		/* The sr is actually a 16 bit register.  */
89 		if (regno == PT_SR)
90 			return *(unsigned short *)addr;
91 	}
92 	return *addr;
93 }
94 
95 /*
96  * Write contents of register REGNO in task TASK.
97  */
put_reg(struct task_struct * task,int regno,unsigned long data)98 static inline int put_reg(struct task_struct *task, int regno,
99 			  unsigned long data)
100 {
101 	unsigned long *addr;
102 
103 	if (regno == PT_USP)
104 		addr = &task->thread.usp;
105 	else if (regno < ARRAY_SIZE(regoff))
106 		addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
107 	else
108 		return -1;
109 	/* Need to take stkadj into account. */
110 	if (regno == PT_SR || regno == PT_PC) {
111 		long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj));
112 		addr = (unsigned long *) ((unsigned long)addr + stkadj);
113 		/* The sr is actually a 16 bit register.  */
114 		if (regno == PT_SR) {
115 			*(unsigned short *)addr = data;
116 			return 0;
117 		}
118 	}
119 	*addr = data;
120 	return 0;
121 }
122 
123 /*
124  * Make sure the single step bit is not set.
125  */
singlestep_disable(struct task_struct * child)126 static inline void singlestep_disable(struct task_struct *child)
127 {
128 	unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
129 	put_reg(child, PT_SR, tmp);
130 	clear_tsk_thread_flag(child, TIF_DELAYED_TRACE);
131 }
132 
133 /*
134  * Called by kernel/ptrace.c when detaching..
135  */
ptrace_disable(struct task_struct * child)136 void ptrace_disable(struct task_struct *child)
137 {
138 	singlestep_disable(child);
139 }
140 
user_enable_single_step(struct task_struct * child)141 void user_enable_single_step(struct task_struct *child)
142 {
143 	unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
144 	put_reg(child, PT_SR, tmp | T1_BIT);
145 	set_tsk_thread_flag(child, TIF_DELAYED_TRACE);
146 }
147 
148 #ifdef CONFIG_MMU
user_enable_block_step(struct task_struct * child)149 void user_enable_block_step(struct task_struct *child)
150 {
151 	unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
152 	put_reg(child, PT_SR, tmp | T0_BIT);
153 }
154 #endif
155 
user_disable_single_step(struct task_struct * child)156 void user_disable_single_step(struct task_struct *child)
157 {
158 	singlestep_disable(child);
159 }
160 
arch_ptrace(struct task_struct * child,long request,unsigned long addr,unsigned long data)161 long arch_ptrace(struct task_struct *child, long request,
162 		 unsigned long addr, unsigned long data)
163 {
164 	unsigned long tmp;
165 	int i, ret = 0;
166 	int regno = addr >> 2; /* temporary hack. */
167 	unsigned long __user *datap = (unsigned long __user *) data;
168 
169 	switch (request) {
170 	/* read the word at location addr in the USER area. */
171 	case PTRACE_PEEKUSR:
172 		if (addr & 3)
173 			goto out_eio;
174 
175 		if (regno >= 0 && regno < 19) {
176 			tmp = get_reg(child, regno);
177 		} else if (regno >= 21 && regno < 49) {
178 			tmp = child->thread.fp[regno - 21];
179 			/* Convert internal fpu reg representation
180 			 * into long double format
181 			 */
182 			if (FPU_IS_EMU && (regno < 45) && !(regno % 3))
183 				tmp = ((tmp & 0xffff0000) << 15) |
184 				      ((tmp & 0x0000ffff) << 16);
185 #ifndef CONFIG_MMU
186 		} else if (regno == 49) {
187 			tmp = child->mm->start_code;
188 		} else if (regno == 50) {
189 			tmp = child->mm->start_data;
190 		} else if (regno == 51) {
191 			tmp = child->mm->end_code;
192 #endif
193 		} else
194 			goto out_eio;
195 		ret = put_user(tmp, datap);
196 		break;
197 
198 	case PTRACE_POKEUSR:
199 	/* write the word at location addr in the USER area */
200 		if (addr & 3)
201 			goto out_eio;
202 
203 		if (regno == PT_SR) {
204 			data &= SR_MASK;
205 			data |= get_reg(child, PT_SR) & ~SR_MASK;
206 		}
207 		if (regno >= 0 && regno < 19) {
208 			if (put_reg(child, regno, data))
209 				goto out_eio;
210 		} else if (regno >= 21 && regno < 48) {
211 			/* Convert long double format
212 			 * into internal fpu reg representation
213 			 */
214 			if (FPU_IS_EMU && (regno < 45) && !(regno % 3)) {
215 				data <<= 15;
216 				data = (data & 0xffff0000) |
217 				       ((data & 0x0000ffff) >> 1);
218 			}
219 			child->thread.fp[regno - 21] = data;
220 		} else
221 			goto out_eio;
222 		break;
223 
224 	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
225 		for (i = 0; i < 19; i++) {
226 			tmp = get_reg(child, i);
227 			ret = put_user(tmp, datap);
228 			if (ret)
229 				break;
230 			datap++;
231 		}
232 		break;
233 
234 	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
235 		for (i = 0; i < 19; i++) {
236 			ret = get_user(tmp, datap);
237 			if (ret)
238 				break;
239 			if (i == PT_SR) {
240 				tmp &= SR_MASK;
241 				tmp |= get_reg(child, PT_SR) & ~SR_MASK;
242 			}
243 			put_reg(child, i, tmp);
244 			datap++;
245 		}
246 		break;
247 
248 	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
249 		if (copy_to_user(datap, &child->thread.fp,
250 				 sizeof(struct user_m68kfp_struct)))
251 			ret = -EFAULT;
252 		break;
253 
254 	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
255 		if (copy_from_user(&child->thread.fp, datap,
256 				   sizeof(struct user_m68kfp_struct)))
257 			ret = -EFAULT;
258 		break;
259 
260 	case PTRACE_GET_THREAD_AREA:
261 		ret = put_user(task_thread_info(child)->tp_value, datap);
262 		break;
263 
264 	default:
265 		ret = ptrace_request(child, request, addr, data);
266 		break;
267 	}
268 
269 	return ret;
270 out_eio:
271 	return -EIO;
272 }
273 
syscall_trace(void)274 asmlinkage void syscall_trace(void)
275 {
276 	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
277 				 ? 0x80 : 0));
278 	/*
279 	 * this isn't the same as continuing with a signal, but it will do
280 	 * for normal use.  strace only continues with a signal if the
281 	 * stopping signal is not SIGTRAP.  -brl
282 	 */
283 	if (current->exit_code) {
284 		send_sig(current->exit_code, current, 1);
285 		current->exit_code = 0;
286 	}
287 }
288 
289 #if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU)
syscall_trace_enter(void)290 asmlinkage int syscall_trace_enter(void)
291 {
292 	int ret = 0;
293 
294 	if (test_thread_flag(TIF_SYSCALL_TRACE))
295 		ret = tracehook_report_syscall_entry(task_pt_regs(current));
296 	return ret;
297 }
298 
syscall_trace_leave(void)299 asmlinkage void syscall_trace_leave(void)
300 {
301 	if (test_thread_flag(TIF_SYSCALL_TRACE))
302 		tracehook_report_syscall_exit(task_pt_regs(current), 0);
303 }
304 #endif /* CONFIG_COLDFIRE */
305