File: /usr/src/linux/arch/m68k/kernel/ptrace.c
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/mm.h>
16 #include <linux/smp.h>
17 #include <linux/smp_lock.h>
18 #include <linux/errno.h>
19 #include <linux/ptrace.h>
20 #include <linux/user.h>
21 #include <linux/config.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). */
48 static 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 */
59 static 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 < sizeof(regoff)/sizeof(regoff[0]))
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 */
75 static 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 < sizeof(regoff)/sizeof(regoff[0]))
83 addr = (unsigned long *) (task->thread.esp0 + regoff[regno]);
84 else
85 return -1;
86 *addr = data;
87 return 0;
88 }
89
90 /*
91 * Called by kernel/ptrace.c when detaching..
92 *
93 * Make sure the single step bit is not set.
94 */
95 void ptrace_disable(struct task_struct *child)
96 {
97 unsigned long tmp;
98 /* make sure the single step bit is not set. */
99 tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
100 put_reg(child, PT_SR, tmp);
101 }
102
103 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
104 {
105 struct task_struct *child;
106 unsigned long flags;
107 int ret;
108
109 lock_kernel();
110 ret = -EPERM;
111 if (request == PTRACE_TRACEME) {
112 /* are we already being traced? */
113 if (current->ptrace & PT_PTRACED)
114 goto out;
115 /* set the ptrace bit in the process flags. */
116 current->ptrace |= PT_PTRACED;
117 ret = 0;
118 goto out;
119 }
120 ret = -ESRCH;
121 read_lock(&tasklist_lock);
122 child = find_task_by_pid(pid);
123 if (child)
124 get_task_struct(child);
125 read_unlock(&tasklist_lock);
126 if (!child)
127 goto out;
128
129 ret = -EPERM;
130 if (pid == 1) /* you may not mess with init */
131 goto out_tsk;
132
133 if (request == PTRACE_ATTACH) {
134 ret = ptrace_attach(child);
135 goto out_tsk;
136 }
137 ret = -ESRCH;
138 if (!(child->ptrace & PT_PTRACED))
139 goto out_tsk;
140 if (child->state != TASK_STOPPED) {
141 if (request != PTRACE_KILL)
142 goto out_tsk;
143 }
144 if (child->p_pptr != current)
145 goto out_tsk;
146
147 switch (request) {
148 /* when I and D space are separate, these will need to be fixed. */
149 case PTRACE_PEEKTEXT: /* read word at location addr. */
150 case PTRACE_PEEKDATA: {
151 unsigned long tmp;
152 int copied;
153
154 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
155 ret = -EIO;
156 if (copied != sizeof(tmp))
157 break;
158 ret = put_user(tmp,(unsigned long *) data);
159 break;
160 }
161
162 /* read the word at location addr in the USER area. */
163 case PTRACE_PEEKUSR: {
164 unsigned long tmp;
165
166 ret = -EIO;
167 if ((addr & 3) || addr < 0 ||
168 addr > sizeof(struct user) - 3)
169 break;
170
171 tmp = 0; /* Default return condition */
172 addr = addr >> 2; /* temporary hack. */
173 ret = -EIO;
174 if (addr < 19) {
175 tmp = get_reg(child, addr);
176 if (addr == PT_SR)
177 tmp >>= 16;
178 } else if (addr >= 21 && addr < 49) {
179 tmp = child->thread.fp[addr - 21];
180 #ifdef CONFIG_M68KFPU_EMU
181 /* Convert internal fpu reg representation
182 * into long double format
183 */
184 if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
185 tmp = ((tmp & 0xffff0000) << 15) |
186 ((tmp & 0x0000ffff) << 16);
187 #endif
188 } else
189 break;
190 ret = put_user(tmp,(unsigned long *) data);
191 break;
192 }
193
194 /* when I and D space are separate, this will have to be fixed. */
195 case PTRACE_POKETEXT: /* write the word at location addr. */
196 case PTRACE_POKEDATA:
197 ret = 0;
198 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
199 break;
200 ret = -EIO;
201 break;
202
203 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
204 ret = -EIO;
205 if ((addr & 3) || addr < 0 ||
206 addr > sizeof(struct user) - 3)
207 break;
208
209 addr = addr >> 2; /* temporary hack. */
210
211 if (addr == PT_SR) {
212 data &= SR_MASK;
213 data <<= 16;
214 data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
215 }
216 if (addr < 19) {
217 if (put_reg(child, addr, data))
218 break;
219 ret = 0;
220 break;
221 }
222 if (addr >= 21 && addr < 48)
223 {
224 #ifdef CONFIG_M68KFPU_EMU
225 /* Convert long double format
226 * into internal fpu reg representation
227 */
228 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
229 data = (unsigned long)data << 15;
230 data = (data & 0xffff0000) |
231 ((data & 0x0000ffff) >> 1);
232 }
233 #endif
234 child->thread.fp[addr - 21] = data;
235 ret = 0;
236 }
237 break;
238
239 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
240 case PTRACE_CONT: { /* restart after signal. */
241 long tmp;
242
243 ret = -EIO;
244 if ((unsigned long) data > _NSIG)
245 break;
246 if (request == PTRACE_SYSCALL)
247 child->ptrace |= PT_TRACESYS;
248 else
249 child->ptrace &= ~PT_TRACESYS;
250 child->exit_code = data;
251 /* make sure the single step bit is not set. */
252 tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
253 put_reg(child, PT_SR, tmp);
254 wake_up_process(child);
255 ret = 0;
256 break;
257 }
258
259 /*
260 * make the child exit. Best I can do is send it a sigkill.
261 * perhaps it should be put in the status that it wants to
262 * exit.
263 */
264 case PTRACE_KILL: {
265 long tmp;
266
267 ret = 0;
268 if (child->state == TASK_ZOMBIE) /* already dead */
269 break;
270 child->exit_code = SIGKILL;
271 /* make sure the single step bit is not set. */
272 tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
273 put_reg(child, PT_SR, tmp);
274 wake_up_process(child);
275 break;
276 }
277
278 case PTRACE_SINGLESTEP: { /* set the trap flag. */
279 long tmp;
280
281 ret = -EIO;
282 if ((unsigned long) data > _NSIG)
283 break;
284 child->ptrace &= ~PT_TRACESYS;
285 tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
286 put_reg(child, PT_SR, tmp);
287
288 child->exit_code = data;
289 /* give it a chance to run. */
290 wake_up_process(child);
291 ret = 0;
292 break;
293 }
294
295 case PTRACE_DETACH: /* detach a process that was attached. */
296 ret = ptrace_detach(child, data);
297 break;
298
299 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
300 int i;
301 unsigned long tmp;
302 for (i = 0; i < 19; i++) {
303 tmp = get_reg(child, i);
304 if (i == PT_SR)
305 tmp >>= 16;
306 if (put_user(tmp, (unsigned long *) data)) {
307 ret = -EFAULT;
308 break;
309 }
310 data += sizeof(long);
311 }
312 ret = 0;
313 break;
314 }
315
316 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
317 int i;
318 unsigned long tmp;
319 for (i = 0; i < 19; i++) {
320 if (get_user(tmp, (unsigned long *) data)) {
321 ret = -EFAULT;
322 break;
323 }
324 if (i == PT_SR) {
325 tmp &= SR_MASK;
326 tmp <<= 16;
327 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
328 }
329 put_reg(child, i, tmp);
330 data += sizeof(long);
331 }
332 ret = 0;
333 break;
334 }
335
336 case PTRACE_GETFPREGS: { /* Get the child FPU state. */
337 ret = 0;
338 if (copy_to_user((void *)data, &child->thread.fp,
339 sizeof(struct user_m68kfp_struct)))
340 ret = -EFAULT;
341 break;
342 }
343
344 case PTRACE_SETFPREGS: { /* Set the child FPU state. */
345 ret = 0;
346 if (copy_from_user(&child->thread.fp, (void *)data,
347 sizeof(struct user_m68kfp_struct)))
348 ret = -EFAULT;
349 break;
350 }
351
352 default:
353 ret = -EIO;
354 break;
355 }
356 out_tsk:
357 free_task_struct(child);
358 out:
359 unlock_kernel();
360 return ret;
361 }
362
363 asmlinkage void syscall_trace(void)
364 {
365 if ((current->ptrace & (PT_PTRACED|PT_TRACESYS))
366 != (PT_PTRACED|PT_TRACESYS))
367 return;
368 current->exit_code = SIGTRAP;
369 current->state = TASK_STOPPED;
370 notify_parent(current, SIGCHLD);
371 schedule();
372 /*
373 * this isn't the same as continuing with a signal, but it will do
374 * for normal use. strace only continues with a signal if the
375 * stopping signal is not SIGTRAP. -brl
376 */
377 if (current->exit_code) {
378 send_sig(current->exit_code, current, 1);
379 current->exit_code = 0;
380 }
381 }
382