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1 | // TODO some minor issues |
2 | /* | |
3 | * This file is subject to the terms and conditions of the GNU General Public | |
4 | * License. See the file "COPYING" in the main directory of this archive | |
5 | * for more details. | |
6 | * | |
7 | * Copyright (C) 2001 - 2005 Tensilica Inc. | |
8 | * | |
9 | * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com> | |
10 | * Chris Zankel <chris@zankel.net> | |
11 | * Scott Foehner<sfoehner@yahoo.com>, | |
12 | * Kevin Chea | |
13 | * Marc Gauthier<marc@tensilica.com> <marc@alumni.uwaterloo.ca> | |
14 | */ | |
15 | ||
16 | #include <linux/config.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/sched.h> | |
19 | #include <linux/mm.h> | |
20 | #include <linux/errno.h> | |
21 | #include <linux/ptrace.h> | |
22 | #include <linux/smp.h> | |
23 | #include <linux/smp_lock.h> | |
24 | #include <linux/security.h> | |
25 | ||
26 | #include <asm/pgtable.h> | |
27 | #include <asm/page.h> | |
28 | #include <asm/system.h> | |
29 | #include <asm/uaccess.h> | |
30 | #include <asm/ptrace.h> | |
31 | #include <asm/elf.h> | |
32 | ||
33 | #define TEST_KERNEL // verify kernel operations FIXME: remove | |
34 | ||
35 | ||
36 | /* | |
37 | * Called by kernel/ptrace.c when detaching.. | |
38 | * | |
39 | * Make sure single step bits etc are not set. | |
40 | */ | |
41 | ||
42 | void ptrace_disable(struct task_struct *child) | |
43 | { | |
44 | /* Nothing to do.. */ | |
45 | } | |
46 | ||
47 | int sys_ptrace(long request, long pid, long addr, long data) | |
48 | { | |
49 | struct task_struct *child; | |
50 | int ret = -EPERM; | |
51 | ||
52 | lock_kernel(); | |
53 | ||
54 | #if 0 | |
55 | if ((int)request != 1) | |
56 | printk("ptrace(r=%d,pid=%d,addr=%08lx,data=%08lx)\n", | |
57 | (int) request, (int) pid, (unsigned long) addr, | |
58 | (unsigned long) data); | |
59 | #endif | |
60 | ||
61 | if (request == PTRACE_TRACEME) { | |
62 | ||
63 | /* Are we already being traced? */ | |
64 | ||
65 | if (current->ptrace & PT_PTRACED) | |
66 | goto out; | |
67 | ||
68 | if ((ret = security_ptrace(current->parent, current))) | |
69 | goto out; | |
70 | ||
71 | /* Set the ptrace bit in the process flags. */ | |
72 | ||
73 | current->ptrace |= PT_PTRACED; | |
74 | ret = 0; | |
75 | goto out; | |
76 | } | |
77 | ||
78 | ret = -ESRCH; | |
79 | read_lock(&tasklist_lock); | |
80 | child = find_task_by_pid(pid); | |
81 | if (child) | |
82 | get_task_struct(child); | |
83 | read_unlock(&tasklist_lock); | |
84 | if (!child) | |
85 | goto out; | |
86 | ||
87 | ret = -EPERM; | |
88 | if (pid == 1) /* you may not mess with init */ | |
89 | goto out; | |
90 | ||
91 | if (request == PTRACE_ATTACH) { | |
92 | ret = ptrace_attach(child); | |
93 | goto out_tsk; | |
94 | } | |
95 | ||
96 | if ((ret = ptrace_check_attach(child, request == PTRACE_KILL)) < 0) | |
97 | goto out_tsk; | |
98 | ||
99 | switch (request) { | |
100 | case PTRACE_PEEKTEXT: /* read word at location addr. */ | |
101 | case PTRACE_PEEKDATA: | |
102 | { | |
103 | unsigned long tmp; | |
104 | int copied; | |
105 | ||
106 | copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); | |
107 | ret = -EIO; | |
108 | if (copied != sizeof(tmp)) | |
109 | break; | |
110 | ret = put_user(tmp,(unsigned long *) data); | |
111 | ||
112 | goto out; | |
113 | } | |
114 | ||
115 | /* Read the word at location addr in the USER area. */ | |
116 | ||
117 | case PTRACE_PEEKUSR: | |
118 | { | |
119 | struct pt_regs *regs; | |
120 | unsigned long tmp; | |
121 | ||
122 | regs = xtensa_pt_regs(child); | |
123 | tmp = 0; /* Default return value. */ | |
124 | ||
125 | switch(addr) { | |
126 | ||
127 | case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1: | |
128 | { | |
129 | int ar = addr - REG_AR_BASE - regs->windowbase * 4; | |
130 | ar &= (XCHAL_NUM_AREGS - 1); | |
131 | if (ar < 16 && ar + (regs->wmask >> 4) * 4 >= 0) | |
132 | tmp = regs->areg[ar]; | |
133 | else | |
134 | ret = -EIO; | |
135 | break; | |
136 | } | |
137 | case REG_A_BASE ... REG_A_BASE + 15: | |
138 | tmp = regs->areg[addr - REG_A_BASE]; | |
139 | break; | |
140 | case REG_PC: | |
141 | tmp = regs->pc; | |
142 | break; | |
143 | case REG_PS: | |
144 | /* Note: PS.EXCM is not set while user task is running; | |
145 | * its being set in regs is for exception handling | |
146 | * convenience. */ | |
147 | tmp = (regs->ps & ~XCHAL_PS_EXCM_MASK); | |
148 | break; | |
149 | case REG_WB: | |
150 | tmp = regs->windowbase; | |
151 | break; | |
152 | case REG_WS: | |
153 | tmp = regs->windowstart; | |
154 | break; | |
155 | case REG_LBEG: | |
156 | tmp = regs->lbeg; | |
157 | break; | |
158 | case REG_LEND: | |
159 | tmp = regs->lend; | |
160 | break; | |
161 | case REG_LCOUNT: | |
162 | tmp = regs->lcount; | |
163 | break; | |
164 | case REG_SAR: | |
165 | tmp = regs->sar; | |
166 | break; | |
167 | case REG_DEPC: | |
168 | tmp = regs->depc; | |
169 | break; | |
170 | case REG_EXCCAUSE: | |
171 | tmp = regs->exccause; | |
172 | break; | |
173 | case REG_EXCVADDR: | |
174 | tmp = regs->excvaddr; | |
175 | break; | |
176 | case SYSCALL_NR: | |
177 | tmp = regs->syscall; | |
178 | break; | |
179 | default: | |
180 | tmp = 0; | |
181 | ret = -EIO; | |
182 | goto out; | |
183 | } | |
184 | ret = put_user(tmp, (unsigned long *) data); | |
185 | goto out; | |
186 | } | |
187 | ||
188 | case PTRACE_POKETEXT: /* write the word at location addr. */ | |
189 | case PTRACE_POKEDATA: | |
190 | if (access_process_vm(child, addr, &data, sizeof(data), 1) | |
191 | == sizeof(data)) | |
192 | break; | |
193 | ret = -EIO; | |
194 | goto out; | |
195 | ||
196 | case PTRACE_POKEUSR: | |
197 | { | |
198 | struct pt_regs *regs; | |
199 | regs = xtensa_pt_regs(child); | |
200 | ||
201 | switch (addr) { | |
202 | case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1: | |
203 | { | |
204 | int ar = addr - REG_AR_BASE - regs->windowbase * 4; | |
205 | if (ar < 16 && ar + (regs->wmask >> 4) * 4 >= 0) | |
206 | regs->areg[ar & (XCHAL_NUM_AREGS - 1)] = data; | |
207 | else | |
208 | ret = -EIO; | |
209 | break; | |
210 | } | |
211 | case REG_A_BASE ... REG_A_BASE + 15: | |
212 | regs->areg[addr - REG_A_BASE] = data; | |
213 | break; | |
214 | case REG_PC: | |
215 | regs->pc = data; | |
216 | break; | |
217 | case SYSCALL_NR: | |
218 | regs->syscall = data; | |
219 | break; | |
220 | #ifdef TEST_KERNEL | |
221 | case REG_WB: | |
222 | regs->windowbase = data; | |
223 | break; | |
224 | case REG_WS: | |
225 | regs->windowstart = data; | |
226 | break; | |
227 | #endif | |
228 | ||
229 | default: | |
230 | /* The rest are not allowed. */ | |
231 | ret = -EIO; | |
232 | break; | |
233 | } | |
234 | break; | |
235 | } | |
236 | ||
237 | /* continue and stop at next (return from) syscall */ | |
238 | case PTRACE_SYSCALL: | |
239 | case PTRACE_CONT: /* restart after signal. */ | |
240 | { | |
241 | ret = -EIO; | |
242 | if ((unsigned long) data > _NSIG) | |
243 | break; | |
244 | if (request == PTRACE_SYSCALL) | |
245 | set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
246 | else | |
247 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
248 | child->exit_code = data; | |
249 | /* Make sure the single step bit is not set. */ | |
250 | child->ptrace &= ~PT_SINGLESTEP; | |
251 | wake_up_process(child); | |
252 | ret = 0; | |
253 | break; | |
254 | } | |
255 | ||
256 | /* | |
257 | * make the child exit. Best I can do is send it a sigkill. | |
258 | * perhaps it should be put in the status that it wants to | |
259 | * exit. | |
260 | */ | |
261 | case PTRACE_KILL: | |
262 | ret = 0; | |
263 | if (child->state == EXIT_ZOMBIE) /* already dead */ | |
264 | break; | |
265 | child->exit_code = SIGKILL; | |
266 | child->ptrace &= ~PT_SINGLESTEP; | |
267 | wake_up_process(child); | |
268 | break; | |
269 | ||
270 | case PTRACE_SINGLESTEP: | |
271 | ret = -EIO; | |
272 | if ((unsigned long) data > _NSIG) | |
273 | break; | |
274 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
275 | child->ptrace |= PT_SINGLESTEP; | |
276 | child->exit_code = data; | |
277 | wake_up_process(child); | |
278 | ret = 0; | |
279 | break; | |
280 | ||
281 | case PTRACE_GETREGS: | |
282 | { | |
283 | /* 'data' points to user memory in which to write. | |
284 | * Mainly due to the non-live register values, we | |
285 | * reformat the register values into something more | |
286 | * standard. For convenience, we use the handy | |
287 | * elf_gregset_t format. */ | |
288 | ||
289 | xtensa_gregset_t format; | |
290 | struct pt_regs *regs = xtensa_pt_regs(child); | |
291 | ||
292 | do_copy_regs (&format, regs, child); | |
293 | ||
294 | /* Now, copy to user space nice and easy... */ | |
295 | ret = 0; | |
296 | if (copy_to_user((void *)data, &format, sizeof(elf_gregset_t))) | |
297 | ret = -EFAULT; | |
298 | break; | |
299 | } | |
300 | ||
301 | case PTRACE_SETREGS: | |
302 | { | |
303 | /* 'data' points to user memory that contains the new | |
304 | * values in the elf_gregset_t format. */ | |
305 | ||
306 | xtensa_gregset_t format; | |
307 | struct pt_regs *regs = xtensa_pt_regs(child); | |
308 | ||
309 | if (copy_from_user(&format,(void *)data,sizeof(elf_gregset_t))){ | |
310 | ret = -EFAULT; | |
311 | break; | |
312 | } | |
313 | ||
314 | /* FIXME: Perhaps we want some sanity checks on | |
315 | * these user-space values? See ARM version. Are | |
316 | * debuggers a security concern? */ | |
317 | ||
318 | do_restore_regs (&format, regs, child); | |
319 | ||
320 | ret = 0; | |
321 | break; | |
322 | } | |
323 | ||
324 | case PTRACE_GETFPREGS: | |
325 | { | |
326 | /* 'data' points to user memory in which to write. | |
327 | * For convenience, we use the handy | |
328 | * elf_fpregset_t format. */ | |
329 | ||
330 | elf_fpregset_t fpregs; | |
331 | struct pt_regs *regs = xtensa_pt_regs(child); | |
332 | ||
333 | do_save_fpregs (&fpregs, regs, child); | |
334 | ||
335 | /* Now, copy to user space nice and easy... */ | |
336 | ret = 0; | |
337 | if (copy_to_user((void *)data, &fpregs, sizeof(elf_fpregset_t))) | |
338 | ret = -EFAULT; | |
339 | ||
340 | break; | |
341 | } | |
342 | ||
343 | case PTRACE_SETFPREGS: | |
344 | { | |
345 | /* 'data' points to user memory that contains the new | |
346 | * values in the elf_fpregset_t format. | |
347 | */ | |
348 | elf_fpregset_t fpregs; | |
349 | struct pt_regs *regs = xtensa_pt_regs(child); | |
350 | ||
351 | ret = 0; | |
352 | if (copy_from_user(&fpregs, (void *)data, sizeof(elf_fpregset_t))) { | |
353 | ret = -EFAULT; | |
354 | break; | |
355 | } | |
356 | ||
357 | if (do_restore_fpregs (&fpregs, regs, child)) | |
358 | ret = -EIO; | |
359 | break; | |
360 | } | |
361 | ||
362 | case PTRACE_GETFPREGSIZE: | |
363 | /* 'data' points to 'unsigned long' set to the size | |
364 | * of elf_fpregset_t | |
365 | */ | |
366 | ret = put_user(sizeof(elf_fpregset_t), (unsigned long *) data); | |
367 | break; | |
368 | ||
369 | case PTRACE_DETACH: /* detach a process that was attached. */ | |
370 | ret = ptrace_detach(child, data); | |
371 | break; | |
372 | ||
373 | default: | |
374 | ret = ptrace_request(child, request, addr, data); | |
375 | goto out; | |
376 | } | |
377 | out_tsk: | |
378 | put_task_struct(child); | |
379 | out: | |
380 | unlock_kernel(); | |
381 | return ret; | |
382 | } | |
383 | ||
384 | void do_syscall_trace(void) | |
385 | { | |
386 | if (!test_thread_flag(TIF_SYSCALL_TRACE)) | |
387 | return; | |
388 | ||
389 | if (!(current->ptrace & PT_PTRACED)) | |
390 | return; | |
391 | ||
392 | /* | |
393 | * The 0x80 provides a way for the tracing parent to distinguish | |
394 | * between a syscall stop and SIGTRAP delivery | |
395 | */ | |
396 | ptrace_notify(SIGTRAP|((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0)); | |
397 | ||
398 | /* | |
399 | * this isn't the same as continuing with a signal, but it will do | |
400 | * for normal use. strace only continues with a signal if the | |
401 | * stopping signal is not SIGTRAP. -brl | |
402 | */ | |
403 | if (current->exit_code) { | |
404 | send_sig(current->exit_code, current, 1); | |
405 | current->exit_code = 0; | |
406 | } | |
407 | } |