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