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
22 #include <asm/uaccess.h>
23 #include <asm/page.h>
24 #include <asm/pgtable.h>
25 #include <asm/system.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 0x8000
39
40 /* Find the stack offset for a register, relative to thread.esp0. */
41 #define PT_REG(reg) ((long)&((struct pt_regs *)0)->reg)
42 #define SW_REG(reg) ((long)&((struct switch_stack *)0)->reg \
43 - sizeof(struct switch_stack))
44 /* Mapping from PT_xxx to the stack offset at which the register is
45 saved. Notice that usp has no stack-slot and needs to be treated
46 specially (see get_reg/put_reg below). */
47 static int regoff[] = {
48 PT_REG(d1), PT_REG(d2), PT_REG(d3), PT_REG(d4),
49 PT_REG(d5), SW_REG(d6), SW_REG(d7), PT_REG(a0),
50 PT_REG(a1), PT_REG(a2), SW_REG(a3), SW_REG(a4),
51 SW_REG(a5), SW_REG(a6), PT_REG(d0), -1,
52 PT_REG(orig_d0), PT_REG(sr), PT_REG(pc),
53 };
54
55 /*
56 * Get contents of register REGNO in task TASK.
57 */
get_reg(struct task_struct * task,int regno)58 static inline long get_reg(struct task_struct *task, int regno)
59 {
60 unsigned long *addr;
61
62 if (regno == PT_USP)
63 addr = &task->thread.usp;
64 else if (regno < ARRAY_SIZE(regoff))
65 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
66 else
67 return 0;
68 return *addr;
69 }
70
71 /*
72 * Write contents of register REGNO in task TASK.
73 */
put_reg(struct task_struct * task,int regno,unsigned long data)74 static inline int put_reg(struct task_struct *task, int regno,
75 unsigned long data)
76 {
77 unsigned long *addr;
78
79 if (regno == PT_USP)
80 addr = &task->thread.usp;
81 else if (regno < ARRAY_SIZE(regoff))
82 addr = (unsigned long *) (task->thread.esp0 + regoff[regno]);
83 else
84 return -1;
85 *addr = data;
86 return 0;
87 }
88
89 /*
90 * Called by kernel/ptrace.c when detaching..
91 *
92 * Make sure the single step bit is not set.
93 */
ptrace_disable(struct task_struct * child)94 void ptrace_disable(struct task_struct *child)
95 {
96 unsigned long tmp;
97 /* make sure the single step bit is not set. */
98 tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
99 put_reg(child, PT_SR, tmp);
100 }
101
arch_ptrace(struct task_struct * child,long request,long addr,long data)102 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
103 {
104 int ret;
105
106 switch (request) {
107 /* when I and D space are separate, these will need to be fixed. */
108 case PTRACE_PEEKTEXT: /* read word at location addr. */
109 case PTRACE_PEEKDATA:
110 ret = generic_ptrace_peekdata(child, addr, data);
111 break;
112
113 /* read the word at location addr in the USER area. */
114 case PTRACE_PEEKUSR: {
115 unsigned long tmp;
116
117 ret = -EIO;
118 if ((addr & 3) || addr < 0 ||
119 addr > sizeof(struct user) - 3)
120 break;
121
122 tmp = 0; /* Default return condition */
123 addr = addr >> 2; /* temporary hack. */
124 ret = -EIO;
125 if (addr < 19) {
126 tmp = get_reg(child, addr);
127 if (addr == PT_SR)
128 tmp >>= 16;
129 } else if (addr >= 21 && addr < 49) {
130 tmp = child->thread.fp[addr - 21];
131 #ifdef CONFIG_M68KFPU_EMU
132 /* Convert internal fpu reg representation
133 * into long double format
134 */
135 if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
136 tmp = ((tmp & 0xffff0000) << 15) |
137 ((tmp & 0x0000ffff) << 16);
138 #endif
139 } else if (addr == 49) {
140 tmp = child->mm->start_code;
141 } else if (addr == 50) {
142 tmp = child->mm->start_data;
143 } else if (addr == 51) {
144 tmp = child->mm->end_code;
145 } else
146 break;
147 ret = put_user(tmp,(unsigned long *) data);
148 break;
149 }
150
151 /* when I and D space are separate, this will have to be fixed. */
152 case PTRACE_POKETEXT: /* write the word at location addr. */
153 case PTRACE_POKEDATA:
154 ret = generic_ptrace_pokedata(child, addr, data);
155 break;
156
157 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
158 ret = -EIO;
159 if ((addr & 3) || addr < 0 ||
160 addr > sizeof(struct user) - 3)
161 break;
162
163 addr = addr >> 2; /* temporary hack. */
164
165 if (addr == PT_SR) {
166 data &= SR_MASK;
167 data <<= 16;
168 data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
169 }
170 if (addr < 19) {
171 if (put_reg(child, addr, data))
172 break;
173 ret = 0;
174 break;
175 }
176 if (addr >= 21 && addr < 48)
177 {
178 #ifdef CONFIG_M68KFPU_EMU
179 /* Convert long double format
180 * into internal fpu reg representation
181 */
182 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
183 data = (unsigned long)data << 15;
184 data = (data & 0xffff0000) |
185 ((data & 0x0000ffff) >> 1);
186 }
187 #endif
188 child->thread.fp[addr - 21] = data;
189 ret = 0;
190 }
191 break;
192
193 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
194 case PTRACE_CONT: { /* restart after signal. */
195 long tmp;
196
197 ret = -EIO;
198 if (!valid_signal(data))
199 break;
200 if (request == PTRACE_SYSCALL)
201 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
202 else
203 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
204 child->exit_code = data;
205 /* make sure the single step bit is not set. */
206 tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
207 put_reg(child, PT_SR, tmp);
208 wake_up_process(child);
209 ret = 0;
210 break;
211 }
212
213 /*
214 * make the child exit. Best I can do is send it a sigkill.
215 * perhaps it should be put in the status that it wants to
216 * exit.
217 */
218 case PTRACE_KILL: {
219 long tmp;
220
221 ret = 0;
222 if (child->exit_state == EXIT_ZOMBIE) /* already dead */
223 break;
224 child->exit_code = SIGKILL;
225 /* make sure the single step bit is not set. */
226 tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
227 put_reg(child, PT_SR, tmp);
228 wake_up_process(child);
229 break;
230 }
231
232 case PTRACE_SINGLESTEP: { /* set the trap flag. */
233 long tmp;
234
235 ret = -EIO;
236 if (!valid_signal(data))
237 break;
238 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
239 tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
240 put_reg(child, PT_SR, tmp);
241
242 child->exit_code = data;
243 /* give it a chance to run. */
244 wake_up_process(child);
245 ret = 0;
246 break;
247 }
248
249 case PTRACE_DETACH: /* detach a process that was attached. */
250 ret = ptrace_detach(child, data);
251 break;
252
253 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
254 int i;
255 unsigned long tmp;
256 for (i = 0; i < 19; i++) {
257 tmp = get_reg(child, i);
258 if (i == PT_SR)
259 tmp >>= 16;
260 if (put_user(tmp, (unsigned long *) data)) {
261 ret = -EFAULT;
262 break;
263 }
264 data += sizeof(long);
265 }
266 ret = 0;
267 break;
268 }
269
270 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
271 int i;
272 unsigned long tmp;
273 for (i = 0; i < 19; i++) {
274 if (get_user(tmp, (unsigned long *) data)) {
275 ret = -EFAULT;
276 break;
277 }
278 if (i == PT_SR) {
279 tmp &= SR_MASK;
280 tmp <<= 16;
281 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
282 }
283 put_reg(child, i, tmp);
284 data += sizeof(long);
285 }
286 ret = 0;
287 break;
288 }
289
290 #ifdef PTRACE_GETFPREGS
291 case PTRACE_GETFPREGS: { /* Get the child FPU state. */
292 ret = 0;
293 if (copy_to_user((void *)data, &child->thread.fp,
294 sizeof(struct user_m68kfp_struct)))
295 ret = -EFAULT;
296 break;
297 }
298 #endif
299
300 #ifdef PTRACE_SETFPREGS
301 case PTRACE_SETFPREGS: { /* Set the child FPU state. */
302 ret = 0;
303 if (copy_from_user(&child->thread.fp, (void *)data,
304 sizeof(struct user_m68kfp_struct)))
305 ret = -EFAULT;
306 break;
307 }
308 #endif
309
310 default:
311 ret = -EIO;
312 break;
313 }
314 return ret;
315 }
316
syscall_trace(void)317 asmlinkage void syscall_trace(void)
318 {
319 if (!test_thread_flag(TIF_SYSCALL_TRACE))
320 return;
321 if (!(current->ptrace & PT_PTRACED))
322 return;
323 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
324 ? 0x80 : 0));
325 /*
326 * this isn't the same as continuing with a signal, but it will do
327 * for normal use. strace only continues with a signal if the
328 * stopping signal is not SIGTRAP. -brl
329 */
330 if (current->exit_code) {
331 send_sig(current->exit_code, current, 1);
332 current->exit_code = 0;
333 }
334 }
335