1 /* $Id: ptrace.c,v 1.1.1.1.2.3 2003/10/23 22:11:08 yoshii Exp $
2 *
3 * linux/arch/sh/kernel/ptrace.c
4 *
5 * Original x86 implementation:
6 * By Ross Biro 1/23/92
7 * edited by Linus Torvalds
8 *
9 * SuperH version: Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka
10 *
11 */
12
13 #include <linux/config.h>
14 #include <linux/kernel.h>
15 #include <linux/sched.h>
16 #include <linux/mm.h>
17 #include <linux/smp.h>
18 #include <linux/smp_lock.h>
19 #include <linux/errno.h>
20 #include <linux/ptrace.h>
21 #include <linux/user.h>
22
23 #include <asm/io.h>
24 #include <asm/uaccess.h>
25 #include <asm/pgtable.h>
26 #include <asm/system.h>
27 #include <asm/processor.h>
28 #include <asm/mmu_context.h>
29
30 /*
31 * does not yet catch signals sent when the child dies.
32 * in exit.c or in signal.c.
33 */
34
35 /*
36 * This routine will get a word off of the process kernel stack.
37 */
get_stack_long(struct task_struct * task,int offset)38 static inline int get_stack_long(struct task_struct *task, int offset)
39 {
40 unsigned char *stack;
41
42 stack = (unsigned char *)task + THREAD_SIZE - sizeof(struct pt_regs);
43 stack += offset;
44 return (*((int *)stack));
45 }
46
47 /*
48 * This routine will put a word on the process kernel stack.
49 */
put_stack_long(struct task_struct * task,int offset,unsigned long data)50 static inline int put_stack_long(struct task_struct *task, int offset,
51 unsigned long data)
52 {
53 unsigned char *stack;
54
55 stack = (unsigned char *)task + THREAD_SIZE - sizeof(struct pt_regs);
56 stack += offset;
57 *(unsigned long *) stack = data;
58 return 0;
59 }
60
61 static void
compute_next_pc(struct pt_regs * regs,unsigned short inst,unsigned long * pc1,unsigned long * pc2)62 compute_next_pc(struct pt_regs *regs, unsigned short inst,
63 unsigned long *pc1, unsigned long *pc2)
64 {
65 int nib[4]
66 = { (inst >> 12) & 0xf,
67 (inst >> 8) & 0xf,
68 (inst >> 4) & 0xf,
69 inst & 0xf};
70
71 /* bra & bsr */
72 if (nib[0] == 0xa || nib[0] == 0xb) {
73 *pc1 = regs->pc + 4 + ((short) ((inst & 0xfff) << 4) >> 3);
74 if(*pc1 == regs->pc + 2)
75 *pc1 = regs->pc + 4;
76 *pc2 = (unsigned long) -1;
77 return;
78 }
79
80 /* bt & bf */
81 if (nib[0] == 0x8 && (nib[1] == 0x9 || nib[1] == 0xb)) {
82 *pc1 = regs->pc + 4 + ((char) (inst & 0xff) << 1);
83 *pc2 = regs->pc + 2;
84 return;
85 }
86
87 /* bt/s & bf/s */
88 if (nib[0] == 0x8 && (nib[1] == 0xd || nib[1] == 0xf)) {
89 *pc1 = regs->pc + 4 + ((char) (inst & 0xff) << 1);
90 if(*pc1 == regs->pc + 2) {
91 *pc1 = regs->pc + 4;
92 *pc2 = (unsigned long) -1;
93 }
94 else
95 *pc2 = regs->pc + 4;
96 return;
97 }
98
99 /* jmp & jsr */
100 if (nib[0] == 0x4 && nib[3] == 0xb
101 && (nib[2] == 0x0 || nib[2] == 0x2)) {
102 *pc1 = regs->regs[nib[1]];
103 if(*pc1 == regs->pc + 2)
104 *pc1 = regs->pc + 4;
105 *pc2 = (unsigned long) -1;
106 return;
107 }
108
109 /* braf & bsrf */
110 if (nib[0] == 0x0 && nib[3] == 0x3
111 && (nib[2] == 0x0 || nib[2] == 0x2)) {
112 *pc1 = regs->pc + 4 + regs->regs[nib[1]];
113 if(*pc1 == regs->pc + 2)
114 *pc1 = regs->pc + 4;
115 *pc2 = (unsigned long) -1;
116 return;
117 }
118
119 if (inst == 0x000b) {
120 *pc1 = regs->pr;
121 if(*pc1 == regs->pc + 2)
122 *pc1 = regs->pc + 4;
123 *pc2 = (unsigned long) -1;
124 return;
125 }
126
127 *pc1 = regs->pc + 2;
128 *pc2 = (unsigned long) -1;
129 return;
130 }
131
132 /*
133 * Called by kernel/ptrace.c when detaching..
134 *
135 * Make sure single step bits etc are not set.
136 */
ptrace_disable(struct task_struct * child)137 void ptrace_disable(struct task_struct *child)
138 {
139 /* nothing to do.. */
140 }
141
sys_ptrace(long request,long pid,long addr,long data)142 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
143 {
144 struct task_struct *child, *tsk = current;
145 struct user * dummy = NULL;
146 int ret;
147
148 lock_kernel();
149 ret = -EPERM;
150 if (request == PTRACE_TRACEME) {
151 /* are we already being traced? */
152 if (current->ptrace & PT_PTRACED)
153 goto out;
154 /* set the ptrace bit in the process flags. */
155 current->ptrace |= PT_PTRACED;
156 ret = 0;
157 goto out;
158 }
159 ret = -ESRCH;
160 read_lock(&tasklist_lock);
161 child = find_task_by_pid(pid);
162 if (child)
163 get_task_struct(child);
164 read_unlock(&tasklist_lock);
165 if (!child)
166 goto out;
167
168 ret = -EPERM;
169 if (pid == 1) /* you may not mess with init */
170 goto out_tsk;
171
172 if (request == PTRACE_ATTACH) {
173 ret = ptrace_attach(child);
174 goto out_tsk;
175 }
176 ret = -ESRCH;
177 if (!(child->ptrace & PT_PTRACED))
178 goto out_tsk;
179 if (child->state != TASK_STOPPED) {
180 if (request != PTRACE_KILL)
181 goto out_tsk;
182 }
183 if (child->p_pptr != tsk)
184 goto out_tsk;
185 switch (request) {
186 /* when I and D space are separate, these will need to be fixed. */
187 case PTRACE_PEEKTEXT: /* read word at location addr. */
188 case PTRACE_PEEKDATA: {
189 unsigned long tmp;
190 int copied;
191
192 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
193 ret = -EIO;
194 if (copied != sizeof(tmp))
195 break;
196 ret = put_user(tmp,(unsigned long *) data);
197 break;
198 }
199
200 /* read the word at location addr in the USER area. */
201 case PTRACE_PEEKUSR: {
202 unsigned long tmp;
203
204 ret = -EIO;
205 if ((addr & 3) || addr < 0 ||
206 addr > sizeof(struct user) - 3)
207 break;
208
209 if (addr < sizeof(struct pt_regs))
210 tmp = get_stack_long(child, addr);
211 else if (addr >= (long) &dummy->fpu &&
212 addr < (long) &dummy->u_fpvalid) {
213 if (!child->used_math) {
214 if (addr == (long)&dummy->fpu.fpscr)
215 tmp = FPSCR_INIT;
216 else
217 tmp = 0;
218 } else
219 tmp = ((long *)&child->thread.fpu)
220 [(addr - (long)&dummy->fpu) >> 2];
221 } else if (addr == (long) &dummy->u_fpvalid)
222 tmp = child->used_math;
223 else
224 tmp = 0;
225 ret = put_user(tmp, (unsigned long *)data);
226 break;
227 }
228
229 /* when I and D space are separate, this will have to be fixed. */
230 case PTRACE_POKETEXT: /* write the word at location addr. */
231 case PTRACE_POKEDATA:
232 ret = 0;
233 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
234 break;
235 ret = -EIO;
236 break;
237
238 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
239 ret = -EIO;
240 if ((addr & 3) || addr < 0 ||
241 addr > sizeof(struct user) - 3)
242 break;
243
244 if (addr < sizeof(struct pt_regs))
245 ret = put_stack_long(child, addr, data);
246 else if (addr >= (long) &dummy->fpu &&
247 addr < (long) &dummy->u_fpvalid) {
248 child->used_math = 1;
249 ((long *)&child->thread.fpu)
250 [(addr - (long)&dummy->fpu) >> 2] = data;
251 ret = 0;
252 } else if (addr == (long) &dummy->u_fpvalid) {
253 child->used_math = data?1:0;
254 ret = 0;
255 }
256 break;
257
258 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
259 case PTRACE_CONT: { /* restart after signal. */
260 ret = -EIO;
261 if ((unsigned long) data > _NSIG)
262 break;
263 if (request == PTRACE_SYSCALL)
264 child->ptrace |= PT_TRACESYS;
265 else
266 child->ptrace &= ~PT_TRACESYS;
267 child->exit_code = data;
268 wake_up_process(child);
269 ret = 0;
270 break;
271 }
272
273 /*
274 * make the child exit. Best I can do is send it a sigkill.
275 * perhaps it should be put in the status that it wants to
276 * exit.
277 */
278 case PTRACE_KILL: {
279 ret = 0;
280 if (child->state == TASK_ZOMBIE) /* already dead */
281 break;
282 child->exit_code = SIGKILL;
283 wake_up_process(child);
284 break;
285 }
286
287 case PTRACE_SINGLESTEP: { /* set the trap flag. */
288 long tmp, pc;
289 struct pt_regs *dummy = NULL;
290 struct pt_regs *regs;
291 unsigned long nextpc1, nextpc2;
292 unsigned short insn;
293
294 ret = -EIO;
295 if ((unsigned long) data > _NSIG)
296 break;
297 child->ptrace &= ~PT_TRACESYS;
298 if ((child->ptrace & PT_DTRACE) == 0) {
299 /* Spurious delayed TF traps may occur */
300 child->ptrace |= PT_DTRACE;
301 }
302
303 /* Compute next pc. */
304 pc = get_stack_long(child, (long)&dummy->pc);
305 regs = (struct pt_regs *)((unsigned long)child + THREAD_SIZE - sizeof(struct pt_regs));
306 if (access_process_vm(child, pc&~3, &tmp, sizeof(tmp), 0) != sizeof(tmp))
307 break;
308
309 #ifdef __LITTLE_ENDIAN__
310 if (pc & 3)
311 insn = tmp >> 16;
312 else
313 insn = tmp & 0xffff;
314 #else
315 if (pc & 3)
316 insn = tmp & 0xffff;
317 else
318 insn = tmp >> 16;
319 #endif
320 compute_next_pc (regs, insn, &nextpc1, &nextpc2);
321
322 if (nextpc1 & 0x80000000)
323 break;
324 if (nextpc2 != (unsigned long) -1 && (nextpc2 & 0x80000000))
325 break;
326
327 /* Next scheduling will set up UBC */
328 if (child->thread.ubc_pc1 == 0)
329 ubc_usercnt += 1;
330 child->thread.ubc_pc1 = nextpc1;
331 child->thread.ubc_pc2 = nextpc2;
332
333 child->exit_code = data;
334 /* give it a chance to run. */
335 wake_up_process(child);
336 ret = 0;
337 break;
338 }
339
340 case PTRACE_DETACH: /* detach a process that was attached. */
341 ret = ptrace_detach(child, data);
342 break;
343
344 case PTRACE_SETOPTIONS: {
345 if (data & PTRACE_O_TRACESYSGOOD)
346 child->ptrace |= PT_TRACESYSGOOD;
347 else
348 child->ptrace &= ~PT_TRACESYSGOOD;
349 ret = 0;
350 break;
351 }
352
353 #ifdef CONFIG_SH_DSP
354 case PTRACE_GETDSPREGS: {
355 unsigned long dp;
356
357 ret = -EIO;
358 dp = ((unsigned long) child) + THREAD_SIZE -
359 sizeof(struct pt_dspregs);
360 if (*((int *) (dp - 4)) == SR_DSP) {
361 copy_to_user(addr, (void *) dp,
362 sizeof(struct pt_dspregs));
363 ret = 0;
364 }
365 break;
366 }
367
368 case PTRACE_SETDSPREGS: {
369 unsigned long dp;
370 int i;
371
372 ret = -EIO;
373 dp = ((unsigned long) child) + THREAD_SIZE -
374 sizeof(struct pt_dspregs);
375 if (*((int *) (dp - 4)) == SR_DSP) {
376 copy_from_user((void *) dp, addr,
377 sizeof(struct pt_dspregs));
378 ret = 0;
379 }
380 break;
381 }
382 #endif
383
384 default:
385 ret = -EIO;
386 break;
387 }
388 out_tsk:
389 free_task_struct(child);
390 out:
391 unlock_kernel();
392 return ret;
393 }
394
syscall_trace(void)395 asmlinkage void syscall_trace(void)
396 {
397 struct task_struct *tsk = current;
398
399 if ((tsk->ptrace & (PT_PTRACED|PT_TRACESYS))
400 != (PT_PTRACED|PT_TRACESYS))
401 return;
402 /* the 0x80 provides a way for the tracing parent to distinguish
403 between a syscall stop and SIGTRAP delivery */
404 tsk->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
405 ? 0x80 : 0);
406 tsk->state = TASK_STOPPED;
407 notify_parent(tsk, SIGCHLD);
408 schedule();
409 /*
410 * this isn't the same as continuing with a signal, but it will do
411 * for normal use. strace only continues with a signal if the
412 * stopping signal is not SIGTRAP. -brl
413 */
414 if (tsk->exit_code) {
415 send_sig(tsk->exit_code, tsk, 1);
416 tsk->exit_code = 0;
417 }
418 }
419