1 /*
2 * File: arch/blackfin/kernel/ptrace.c
3 * Based on: Taken from linux/kernel/ptrace.c
4 * Author: linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
5 *
6 * Created: 1/23/92
7 * Description:
8 *
9 * Modified:
10 * Copyright 2004-2006 Analog Devices Inc.
11 *
12 * Bugs: Enter bugs at http://blackfin.uclinux.org/
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
18 *
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with this program; if not, see the file COPYING, or write
26 * to the Free Software Foundation, Inc.,
27 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
28 */
29
30 #include <linux/kernel.h>
31 #include <linux/sched.h>
32 #include <linux/mm.h>
33 #include <linux/smp.h>
34 #include <linux/smp_lock.h>
35 #include <linux/errno.h>
36 #include <linux/ptrace.h>
37 #include <linux/user.h>
38 #include <linux/signal.h>
39 #include <linux/uaccess.h>
40
41 #include <asm/page.h>
42 #include <asm/pgtable.h>
43 #include <asm/system.h>
44 #include <asm/processor.h>
45 #include <asm/asm-offsets.h>
46 #include <asm/dma.h>
47 #include <asm/fixed_code.h>
48 #include <asm/cacheflush.h>
49 #include <asm/mem_map.h>
50
51 #define TEXT_OFFSET 0
52 /*
53 * does not yet catch signals sent when the child dies.
54 * in exit.c or in signal.c.
55 */
56
57 /* determines which bits in the SYSCFG reg the user has access to. */
58 /* 1 = access 0 = no access */
59 #define SYSCFG_MASK 0x0007 /* SYSCFG reg */
60 /* sets the trace bits. */
61 #define TRACE_BITS 0x0001
62
63 /* Find the stack offset for a register, relative to thread.esp0. */
64 #define PT_REG(reg) ((long)&((struct pt_regs *)0)->reg)
65
66 /*
67 * Get the address of the live pt_regs for the specified task.
68 * These are saved onto the top kernel stack when the process
69 * is not running.
70 *
71 * Note: if a user thread is execve'd from kernel space, the
72 * kernel stack will not be empty on entry to the kernel, so
73 * ptracing these tasks will fail.
74 */
get_user_regs(struct task_struct * task)75 static inline struct pt_regs *get_user_regs(struct task_struct *task)
76 {
77 return (struct pt_regs *)
78 ((unsigned long)task_stack_page(task) +
79 (THREAD_SIZE - sizeof(struct pt_regs)));
80 }
81
82 /*
83 * Get all user integer registers.
84 */
ptrace_getregs(struct task_struct * tsk,void __user * uregs)85 static inline int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
86 {
87 struct pt_regs regs;
88 memcpy(®s, get_user_regs(tsk), sizeof(regs));
89 regs.usp = tsk->thread.usp;
90 return copy_to_user(uregs, ®s, sizeof(struct pt_regs)) ? -EFAULT : 0;
91 }
92
93 /* Mapping from PT_xxx to the stack offset at which the register is
94 * saved. Notice that usp has no stack-slot and needs to be treated
95 * specially (see get_reg/put_reg below).
96 */
97
98 /*
99 * Get contents of register REGNO in task TASK.
100 */
get_reg(struct task_struct * task,int regno)101 static inline long get_reg(struct task_struct *task, int regno)
102 {
103 unsigned char *reg_ptr;
104
105 struct pt_regs *regs =
106 (struct pt_regs *)((unsigned long)task_stack_page(task) +
107 (THREAD_SIZE - sizeof(struct pt_regs)));
108 reg_ptr = (char *)regs;
109
110 switch (regno) {
111 case PT_USP:
112 return task->thread.usp;
113 default:
114 if (regno <= 216)
115 return *(long *)(reg_ptr + regno);
116 }
117 /* slight mystery ... never seems to come here but kernel misbehaves without this code! */
118
119 printk(KERN_WARNING "Request to get for unknown register %d\n", regno);
120 return 0;
121 }
122
123 /*
124 * Write contents of register REGNO in task TASK.
125 */
126 static inline int
put_reg(struct task_struct * task,int regno,unsigned long data)127 put_reg(struct task_struct *task, int regno, unsigned long data)
128 {
129 char *reg_ptr;
130
131 struct pt_regs *regs =
132 (struct pt_regs *)((unsigned long)task_stack_page(task) +
133 (THREAD_SIZE - sizeof(struct pt_regs)));
134 reg_ptr = (char *)regs;
135
136 switch (regno) {
137 case PT_PC:
138 /*********************************************************************/
139 /* At this point the kernel is most likely in exception. */
140 /* The RETX register will be used to populate the pc of the process. */
141 /*********************************************************************/
142 regs->retx = data;
143 regs->pc = data;
144 break;
145 case PT_RETX:
146 break; /* regs->retx = data; break; */
147 case PT_USP:
148 regs->usp = data;
149 task->thread.usp = data;
150 break;
151 default:
152 if (regno <= 216)
153 *(long *)(reg_ptr + regno) = data;
154 }
155 return 0;
156 }
157
158 /*
159 * check that an address falls within the bounds of the target process's memory mappings
160 */
is_user_addr_valid(struct task_struct * child,unsigned long start,unsigned long len)161 static inline int is_user_addr_valid(struct task_struct *child,
162 unsigned long start, unsigned long len)
163 {
164 struct vm_area_struct *vma;
165 struct sram_list_struct *sraml;
166
167 /* overflow */
168 if (start + len < start)
169 return -EIO;
170
171 vma = find_vma(child->mm, start);
172 if (vma && start >= vma->vm_start && start + len <= vma->vm_end)
173 return 0;
174
175 for (sraml = child->mm->context.sram_list; sraml; sraml = sraml->next)
176 if (start >= (unsigned long)sraml->addr
177 && start + len < (unsigned long)sraml->addr + sraml->length)
178 return 0;
179
180 if (start >= FIXED_CODE_START && start + len < FIXED_CODE_END)
181 return 0;
182
183 return -EIO;
184 }
185
ptrace_enable(struct task_struct * child)186 void ptrace_enable(struct task_struct *child)
187 {
188 unsigned long tmp;
189 tmp = get_reg(child, PT_SYSCFG) | (TRACE_BITS);
190 put_reg(child, PT_SYSCFG, tmp);
191 }
192
193 /*
194 * Called by kernel/ptrace.c when detaching..
195 *
196 * Make sure the single step bit is not set.
197 */
ptrace_disable(struct task_struct * child)198 void ptrace_disable(struct task_struct *child)
199 {
200 unsigned long tmp;
201 /* make sure the single step bit is not set. */
202 tmp = get_reg(child, PT_SYSCFG) & ~TRACE_BITS;
203 put_reg(child, PT_SYSCFG, tmp);
204 }
205
arch_ptrace(struct task_struct * child,long request,long addr,long data)206 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
207 {
208 int ret;
209 unsigned long __user *datap = (unsigned long __user *)data;
210
211 switch (request) {
212 /* when I and D space are separate, these will need to be fixed. */
213 case PTRACE_PEEKDATA:
214 pr_debug("ptrace: PEEKDATA\n");
215 /* fall through */
216 case PTRACE_PEEKTEXT: /* read word at location addr. */
217 {
218 unsigned long tmp = 0;
219 int copied;
220
221 ret = -EIO;
222 pr_debug("ptrace: PEEKTEXT at addr 0x%08lx + %ld\n", addr, sizeof(data));
223 if (is_user_addr_valid(child, addr, sizeof(tmp)) < 0)
224 break;
225 pr_debug("ptrace: user address is valid\n");
226
227 if (L1_CODE_LENGTH != 0 && addr >= get_l1_code_start()
228 && addr + sizeof(tmp) <= get_l1_code_start() + L1_CODE_LENGTH) {
229 safe_dma_memcpy (&tmp, (const void *)(addr), sizeof(tmp));
230 copied = sizeof(tmp);
231
232 } else if (L1_DATA_A_LENGTH != 0 && addr >= L1_DATA_A_START
233 && addr + sizeof(tmp) <= L1_DATA_A_START + L1_DATA_A_LENGTH) {
234 memcpy(&tmp, (const void *)(addr), sizeof(tmp));
235 copied = sizeof(tmp);
236
237 } else if (L1_DATA_B_LENGTH != 0 && addr >= L1_DATA_B_START
238 && addr + sizeof(tmp) <= L1_DATA_B_START + L1_DATA_B_LENGTH) {
239 memcpy(&tmp, (const void *)(addr), sizeof(tmp));
240 copied = sizeof(tmp);
241
242 } else if (addr >= FIXED_CODE_START
243 && addr + sizeof(tmp) <= FIXED_CODE_END) {
244 copy_from_user_page(0, 0, 0, &tmp, (const void *)(addr), sizeof(tmp));
245 copied = sizeof(tmp);
246
247 } else
248 copied = access_process_vm(child, addr, &tmp,
249 sizeof(tmp), 0);
250
251 pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
252 if (copied != sizeof(tmp))
253 break;
254 ret = put_user(tmp, datap);
255 break;
256 }
257
258 /* read the word at location addr in the USER area. */
259 case PTRACE_PEEKUSR:
260 {
261 unsigned long tmp;
262 ret = -EIO;
263 tmp = 0;
264 if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
265 printk(KERN_WARNING "ptrace error : PEEKUSR : temporarily returning "
266 "0 - %x sizeof(pt_regs) is %lx\n",
267 (int)addr, sizeof(struct pt_regs));
268 break;
269 }
270 if (addr == sizeof(struct pt_regs)) {
271 /* PT_TEXT_ADDR */
272 tmp = child->mm->start_code + TEXT_OFFSET;
273 } else if (addr == (sizeof(struct pt_regs) + 4)) {
274 /* PT_TEXT_END_ADDR */
275 tmp = child->mm->end_code;
276 } else if (addr == (sizeof(struct pt_regs) + 8)) {
277 /* PT_DATA_ADDR */
278 tmp = child->mm->start_data;
279 #ifdef CONFIG_BINFMT_ELF_FDPIC
280 } else if (addr == (sizeof(struct pt_regs) + 12)) {
281 tmp = child->mm->context.exec_fdpic_loadmap;
282 } else if (addr == (sizeof(struct pt_regs) + 16)) {
283 tmp = child->mm->context.interp_fdpic_loadmap;
284 #endif
285 } else {
286 tmp = get_reg(child, addr);
287 }
288 ret = put_user(tmp, datap);
289 break;
290 }
291
292 /* when I and D space are separate, this will have to be fixed. */
293 case PTRACE_POKEDATA:
294 pr_debug("ptrace: PTRACE_PEEKDATA\n");
295 /* fall through */
296 case PTRACE_POKETEXT: /* write the word at location addr. */
297 {
298 int copied;
299
300 ret = -EIO;
301 pr_debug("ptrace: POKETEXT at addr 0x%08lx + %ld bytes %lx\n",
302 addr, sizeof(data), data);
303 if (is_user_addr_valid(child, addr, sizeof(data)) < 0)
304 break;
305 pr_debug("ptrace: user address is valid\n");
306
307 if (L1_CODE_LENGTH != 0 && addr >= get_l1_code_start()
308 && addr + sizeof(data) <= get_l1_code_start() + L1_CODE_LENGTH) {
309 safe_dma_memcpy ((void *)(addr), &data, sizeof(data));
310 copied = sizeof(data);
311
312 } else if (L1_DATA_A_LENGTH != 0 && addr >= L1_DATA_A_START
313 && addr + sizeof(data) <= L1_DATA_A_START + L1_DATA_A_LENGTH) {
314 memcpy((void *)(addr), &data, sizeof(data));
315 copied = sizeof(data);
316
317 } else if (L1_DATA_B_LENGTH != 0 && addr >= L1_DATA_B_START
318 && addr + sizeof(data) <= L1_DATA_B_START + L1_DATA_B_LENGTH) {
319 memcpy((void *)(addr), &data, sizeof(data));
320 copied = sizeof(data);
321
322 } else if (addr >= FIXED_CODE_START
323 && addr + sizeof(data) <= FIXED_CODE_END) {
324 copy_to_user_page(0, 0, 0, (void *)(addr), &data, sizeof(data));
325 copied = sizeof(data);
326
327 } else
328 copied = access_process_vm(child, addr, &data,
329 sizeof(data), 1);
330
331 pr_debug("ptrace: copied size %d\n", copied);
332 if (copied != sizeof(data))
333 break;
334 ret = 0;
335 break;
336 }
337
338 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
339 ret = -EIO;
340 if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
341 printk(KERN_WARNING "ptrace error : POKEUSR: temporarily returning 0\n");
342 break;
343 }
344
345 if (addr >= (sizeof(struct pt_regs))) {
346 ret = 0;
347 break;
348 }
349 if (addr == PT_SYSCFG) {
350 data &= SYSCFG_MASK;
351 data |= get_reg(child, PT_SYSCFG);
352 }
353 ret = put_reg(child, addr, data);
354 break;
355
356 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
357 case PTRACE_CONT: /* restart after signal. */
358 pr_debug("ptrace: syscall/cont\n");
359
360 ret = -EIO;
361 if (!valid_signal(data))
362 break;
363 if (request == PTRACE_SYSCALL)
364 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
365 else
366 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
367 child->exit_code = data;
368 ptrace_disable(child);
369 pr_debug("ptrace: before wake_up_process\n");
370 wake_up_process(child);
371 ret = 0;
372 break;
373
374 /*
375 * make the child exit. Best I can do is send it a sigkill.
376 * perhaps it should be put in the status that it wants to
377 * exit.
378 */
379 case PTRACE_KILL:
380 ret = 0;
381 if (child->exit_state == EXIT_ZOMBIE) /* already dead */
382 break;
383 child->exit_code = SIGKILL;
384 ptrace_disable(child);
385 wake_up_process(child);
386 break;
387
388 case PTRACE_SINGLESTEP: /* set the trap flag. */
389 pr_debug("ptrace: single step\n");
390 ret = -EIO;
391 if (!valid_signal(data))
392 break;
393 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
394 ptrace_enable(child);
395 child->exit_code = data;
396 wake_up_process(child);
397 ret = 0;
398 break;
399
400 case PTRACE_GETREGS:
401 /* Get all gp regs from the child. */
402 ret = ptrace_getregs(child, datap);
403 break;
404
405 case PTRACE_SETREGS:
406 printk(KERN_WARNING "ptrace: SETREGS: **** NOT IMPLEMENTED ***\n");
407 /* Set all gp regs in the child. */
408 ret = 0;
409 break;
410
411 default:
412 ret = ptrace_request(child, request, addr, data);
413 break;
414 }
415
416 return ret;
417 }
418
syscall_trace(void)419 asmlinkage void syscall_trace(void)
420 {
421 if (!test_thread_flag(TIF_SYSCALL_TRACE))
422 return;
423
424 if (!(current->ptrace & PT_PTRACED))
425 return;
426
427 /* the 0x80 provides a way for the tracing parent to distinguish
428 * between a syscall stop and SIGTRAP delivery
429 */
430 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
431 ? 0x80 : 0));
432
433 /*
434 * this isn't the same as continuing with a signal, but it will do
435 * for normal use. strace only continues with a signal if the
436 * stopping signal is not SIGTRAP. -brl
437 */
438 if (current->exit_code) {
439 send_sig(current->exit_code, current, 1);
440 current->exit_code = 0;
441 }
442 }
443