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ptrace_64.c
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1 /*
2  * arch/sh/kernel/ptrace_64.c
3  *
4  * Copyright (C) 2000, 2001 Paolo Alberelli
5  * Copyright (C) 2003 - 2008 Paul Mundt
6  *
7  * Started from SH3/4 version:
8  * SuperH version: Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka
9  *
10  * Original x86 implementation:
11  * By Ross Biro 1/23/92
12  * edited by Linus Torvalds
13  *
14  * This file is subject to the terms and conditions of the GNU General Public
15  * License. See the file "COPYING" in the main directory of this archive
16  * for more details.
17  */
18 #include <linux/kernel.h>
19 #include <linux/rwsem.h>
20 #include <linux/sched.h>
21 #include <linux/mm.h>
22 #include <linux/smp.h>
23 #include <linux/bitops.h>
24 #include <linux/errno.h>
25 #include <linux/ptrace.h>
26 #include <linux/user.h>
27 #include <linux/signal.h>
28 #include <linux/syscalls.h>
29 #include <linux/audit.h>
30 #include <linux/seccomp.h>
31 #include <linux/tracehook.h>
32 #include <linux/elf.h>
33 #include <linux/regset.h>
34 #include <asm/io.h>
35 #include <asm/uaccess.h>
36 #include <asm/pgtable.h>
37 #include <asm/processor.h>
38 #include <asm/mmu_context.h>
39 #include <asm/syscalls.h>
40 #include <asm/fpu.h>
41 #include <asm/traps.h>
42 
43 #define CREATE_TRACE_POINTS
44 #include <trace/events/syscalls.h>
45 
46 /* This mask defines the bits of the SR which the user is not allowed to
47  change, which are everything except S, Q, M, PR, SZ, FR. */
48 #define SR_MASK (0xffff8cfd)
49 
50 /*
51  * does not yet catch signals sent when the child dies.
52  * in exit.c or in signal.c.
53  */
54 
55 /*
56  * This routine will get a word from the user area in the process kernel stack.
57  */
58 static inline int get_stack_long(struct task_struct *task, int offset)
59 {
60  unsigned char *stack;
61 
62  stack = (unsigned char *)(task->thread.uregs);
63  stack += offset;
64  return (*((int *)stack));
65 }
66 
67 static inline unsigned long
68 get_fpu_long(struct task_struct *task, unsigned long addr)
69 {
70  unsigned long tmp;
71  struct pt_regs *regs;
72  regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
73 
74  if (!tsk_used_math(task)) {
75  if (addr == offsetof(struct user_fpu_struct, fpscr)) {
76  tmp = FPSCR_INIT;
77  } else {
78  tmp = 0xffffffffUL; /* matches initial value in fpu.c */
79  }
80  return tmp;
81  }
82 
83  if (last_task_used_math == task) {
84  enable_fpu();
85  save_fpu(task);
86  disable_fpu();
87  last_task_used_math = 0;
88  regs->sr |= SR_FD;
89  }
90 
91  tmp = ((long *)task->thread.xstate)[addr / sizeof(unsigned long)];
92  return tmp;
93 }
94 
95 /*
96  * This routine will put a word into the user area in the process kernel stack.
97  */
98 static inline int put_stack_long(struct task_struct *task, int offset,
99  unsigned long data)
100 {
101  unsigned char *stack;
102 
103  stack = (unsigned char *)(task->thread.uregs);
104  stack += offset;
105  *(unsigned long *) stack = data;
106  return 0;
107 }
108 
109 static inline int
110 put_fpu_long(struct task_struct *task, unsigned long addr, unsigned long data)
111 {
112  struct pt_regs *regs;
113 
114  regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
115 
116  if (!tsk_used_math(task)) {
117  init_fpu(task);
118  } else if (last_task_used_math == task) {
119  enable_fpu();
120  save_fpu(task);
121  disable_fpu();
122  last_task_used_math = 0;
123  regs->sr |= SR_FD;
124  }
125 
126  ((long *)task->thread.xstate)[addr / sizeof(unsigned long)] = data;
127  return 0;
128 }
129 
130 void user_enable_single_step(struct task_struct *child)
131 {
132  struct pt_regs *regs = child->thread.uregs;
133 
134  regs->sr |= SR_SSTEP; /* auto-resetting upon exception */
135 
136  set_tsk_thread_flag(child, TIF_SINGLESTEP);
137 }
138 
139 void user_disable_single_step(struct task_struct *child)
140 {
141  struct pt_regs *regs = child->thread.uregs;
142 
143  regs->sr &= ~SR_SSTEP;
144 
145  clear_tsk_thread_flag(child, TIF_SINGLESTEP);
146 }
147 
148 static int genregs_get(struct task_struct *target,
149  const struct user_regset *regset,
150  unsigned int pos, unsigned int count,
151  void *kbuf, void __user *ubuf)
152 {
153  const struct pt_regs *regs = task_pt_regs(target);
154  int ret;
155 
156  /* PC, SR, SYSCALL */
157  ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
158  &regs->pc,
159  0, 3 * sizeof(unsigned long long));
160 
161  /* R1 -> R63 */
162  if (!ret)
163  ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
164  regs->regs,
165  offsetof(struct pt_regs, regs[0]),
166  63 * sizeof(unsigned long long));
167  /* TR0 -> TR7 */
168  if (!ret)
169  ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
170  regs->tregs,
171  offsetof(struct pt_regs, tregs[0]),
172  8 * sizeof(unsigned long long));
173 
174  if (!ret)
175  ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
176  sizeof(struct pt_regs), -1);
177 
178  return ret;
179 }
180 
181 static int genregs_set(struct task_struct *target,
182  const struct user_regset *regset,
183  unsigned int pos, unsigned int count,
184  const void *kbuf, const void __user *ubuf)
185 {
186  struct pt_regs *regs = task_pt_regs(target);
187  int ret;
188 
189  /* PC, SR, SYSCALL */
190  ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
191  &regs->pc,
192  0, 3 * sizeof(unsigned long long));
193 
194  /* R1 -> R63 */
195  if (!ret && count > 0)
196  ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
197  regs->regs,
198  offsetof(struct pt_regs, regs[0]),
199  63 * sizeof(unsigned long long));
200 
201  /* TR0 -> TR7 */
202  if (!ret && count > 0)
203  ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
204  regs->tregs,
205  offsetof(struct pt_regs, tregs[0]),
206  8 * sizeof(unsigned long long));
207 
208  if (!ret)
209  ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
210  sizeof(struct pt_regs), -1);
211 
212  return ret;
213 }
214 
215 #ifdef CONFIG_SH_FPU
216 int fpregs_get(struct task_struct *target,
217  const struct user_regset *regset,
218  unsigned int pos, unsigned int count,
219  void *kbuf, void __user *ubuf)
220 {
221  int ret;
222 
223  ret = init_fpu(target);
224  if (ret)
225  return ret;
226 
227  return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
228  &target->thread.xstate->hardfpu, 0, -1);
229 }
230 
231 static int fpregs_set(struct task_struct *target,
232  const struct user_regset *regset,
233  unsigned int pos, unsigned int count,
234  const void *kbuf, const void __user *ubuf)
235 {
236  int ret;
237 
238  ret = init_fpu(target);
239  if (ret)
240  return ret;
241 
242  set_stopped_child_used_math(target);
243 
244  return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
245  &target->thread.xstate->hardfpu, 0, -1);
246 }
247 
248 static int fpregs_active(struct task_struct *target,
249  const struct user_regset *regset)
250 {
251  return tsk_used_math(target) ? regset->n : 0;
252 }
253 #endif
254 
255 const struct pt_regs_offset regoffset_table[] = {
256  REG_OFFSET_NAME(pc),
257  REG_OFFSET_NAME(sr),
258  REG_OFFSET_NAME(syscall_nr),
259  REGS_OFFSET_NAME(0),
260  REGS_OFFSET_NAME(1),
261  REGS_OFFSET_NAME(2),
262  REGS_OFFSET_NAME(3),
263  REGS_OFFSET_NAME(4),
264  REGS_OFFSET_NAME(5),
265  REGS_OFFSET_NAME(6),
266  REGS_OFFSET_NAME(7),
267  REGS_OFFSET_NAME(8),
268  REGS_OFFSET_NAME(9),
269  REGS_OFFSET_NAME(10),
270  REGS_OFFSET_NAME(11),
271  REGS_OFFSET_NAME(12),
272  REGS_OFFSET_NAME(13),
273  REGS_OFFSET_NAME(14),
274  REGS_OFFSET_NAME(15),
275  REGS_OFFSET_NAME(16),
276  REGS_OFFSET_NAME(17),
277  REGS_OFFSET_NAME(18),
278  REGS_OFFSET_NAME(19),
279  REGS_OFFSET_NAME(20),
280  REGS_OFFSET_NAME(21),
281  REGS_OFFSET_NAME(22),
282  REGS_OFFSET_NAME(23),
283  REGS_OFFSET_NAME(24),
284  REGS_OFFSET_NAME(25),
285  REGS_OFFSET_NAME(26),
286  REGS_OFFSET_NAME(27),
287  REGS_OFFSET_NAME(28),
288  REGS_OFFSET_NAME(29),
289  REGS_OFFSET_NAME(30),
290  REGS_OFFSET_NAME(31),
291  REGS_OFFSET_NAME(32),
292  REGS_OFFSET_NAME(33),
293  REGS_OFFSET_NAME(34),
294  REGS_OFFSET_NAME(35),
295  REGS_OFFSET_NAME(36),
296  REGS_OFFSET_NAME(37),
297  REGS_OFFSET_NAME(38),
298  REGS_OFFSET_NAME(39),
299  REGS_OFFSET_NAME(40),
300  REGS_OFFSET_NAME(41),
301  REGS_OFFSET_NAME(42),
302  REGS_OFFSET_NAME(43),
303  REGS_OFFSET_NAME(44),
304  REGS_OFFSET_NAME(45),
305  REGS_OFFSET_NAME(46),
306  REGS_OFFSET_NAME(47),
307  REGS_OFFSET_NAME(48),
308  REGS_OFFSET_NAME(49),
309  REGS_OFFSET_NAME(50),
310  REGS_OFFSET_NAME(51),
311  REGS_OFFSET_NAME(52),
312  REGS_OFFSET_NAME(53),
313  REGS_OFFSET_NAME(54),
314  REGS_OFFSET_NAME(55),
315  REGS_OFFSET_NAME(56),
316  REGS_OFFSET_NAME(57),
317  REGS_OFFSET_NAME(58),
318  REGS_OFFSET_NAME(59),
319  REGS_OFFSET_NAME(60),
320  REGS_OFFSET_NAME(61),
321  REGS_OFFSET_NAME(62),
322  REGS_OFFSET_NAME(63),
323  TREGS_OFFSET_NAME(0),
324  TREGS_OFFSET_NAME(1),
325  TREGS_OFFSET_NAME(2),
326  TREGS_OFFSET_NAME(3),
327  TREGS_OFFSET_NAME(4),
328  TREGS_OFFSET_NAME(5),
329  TREGS_OFFSET_NAME(6),
330  TREGS_OFFSET_NAME(7),
331  REG_OFFSET_END,
332 };
333 
334 /*
335  * These are our native regset flavours.
336  */
337 enum sh_regset {
338  REGSET_GENERAL,
339 #ifdef CONFIG_SH_FPU
340  REGSET_FPU,
341 #endif
342 };
343 
344 static const struct user_regset sh_regsets[] = {
345  /*
346  * Format is:
347  * PC, SR, SYSCALL,
348  * R1 --> R63,
349  * TR0 --> TR7,
350  */
351  [REGSET_GENERAL] = {
352  .core_note_type = NT_PRSTATUS,
353  .n = ELF_NGREG,
354  .size = sizeof(long long),
355  .align = sizeof(long long),
356  .get = genregs_get,
357  .set = genregs_set,
358  },
359 
360 #ifdef CONFIG_SH_FPU
361  [REGSET_FPU] = {
362  .core_note_type = NT_PRFPREG,
363  .n = sizeof(struct user_fpu_struct) /
364  sizeof(long long),
365  .size = sizeof(long long),
366  .align = sizeof(long long),
367  .get = fpregs_get,
368  .set = fpregs_set,
369  .active = fpregs_active,
370  },
371 #endif
372 };
373 
374 static const struct user_regset_view user_sh64_native_view = {
375  .name = "sh64",
376  .e_machine = EM_SH,
377  .regsets = sh_regsets,
378  .n = ARRAY_SIZE(sh_regsets),
379 };
380 
381 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
382 {
383  return &user_sh64_native_view;
384 }
385 
386 long arch_ptrace(struct task_struct *child, long request,
387  unsigned long addr, unsigned long data)
388 {
389  int ret;
390  unsigned long __user *datap = (unsigned long __user *) data;
391 
392  switch (request) {
393  /* read the word at location addr in the USER area. */
394  case PTRACE_PEEKUSR: {
395  unsigned long tmp;
396 
397  ret = -EIO;
398  if ((addr & 3) || addr < 0)
399  break;
400 
401  if (addr < sizeof(struct pt_regs))
402  tmp = get_stack_long(child, addr);
403  else if ((addr >= offsetof(struct user, fpu)) &&
404  (addr < offsetof(struct user, u_fpvalid))) {
405  unsigned long index;
406  ret = init_fpu(child);
407  if (ret)
408  break;
409  index = addr - offsetof(struct user, fpu);
410  tmp = get_fpu_long(child, index);
411  } else if (addr == offsetof(struct user, u_fpvalid)) {
412  tmp = !!tsk_used_math(child);
413  } else {
414  break;
415  }
416  ret = put_user(tmp, datap);
417  break;
418  }
419 
420  case PTRACE_POKEUSR:
421  /* write the word at location addr in the USER area. We must
422  disallow any changes to certain SR bits or u_fpvalid, since
423  this could crash the kernel or result in a security
424  loophole. */
425  ret = -EIO;
426  if ((addr & 3) || addr < 0)
427  break;
428 
429  if (addr < sizeof(struct pt_regs)) {
430  /* Ignore change of top 32 bits of SR */
431  if (addr == offsetof (struct pt_regs, sr)+4)
432  {
433  ret = 0;
434  break;
435  }
436  /* If lower 32 bits of SR, ignore non-user bits */
437  if (addr == offsetof (struct pt_regs, sr))
438  {
439  long cursr = get_stack_long(child, addr);
440  data &= ~(SR_MASK);
441  data |= (cursr & SR_MASK);
442  }
443  ret = put_stack_long(child, addr, data);
444  }
445  else if ((addr >= offsetof(struct user, fpu)) &&
446  (addr < offsetof(struct user, u_fpvalid))) {
447  unsigned long index;
448  ret = init_fpu(child);
449  if (ret)
450  break;
451  index = addr - offsetof(struct user, fpu);
452  ret = put_fpu_long(child, index, data);
453  }
454  break;
455 
456  case PTRACE_GETREGS:
457  return copy_regset_to_user(child, &user_sh64_native_view,
458  REGSET_GENERAL,
459  0, sizeof(struct pt_regs),
460  datap);
461  case PTRACE_SETREGS:
462  return copy_regset_from_user(child, &user_sh64_native_view,
463  REGSET_GENERAL,
464  0, sizeof(struct pt_regs),
465  datap);
466 #ifdef CONFIG_SH_FPU
467  case PTRACE_GETFPREGS:
468  return copy_regset_to_user(child, &user_sh64_native_view,
469  REGSET_FPU,
470  0, sizeof(struct user_fpu_struct),
471  datap);
472  case PTRACE_SETFPREGS:
473  return copy_regset_from_user(child, &user_sh64_native_view,
474  REGSET_FPU,
475  0, sizeof(struct user_fpu_struct),
476  datap);
477 #endif
478  default:
479  ret = ptrace_request(child, request, addr, data);
480  break;
481  }
482 
483  return ret;
484 }
485 
486 asmlinkage int sh64_ptrace(long request, long pid,
487  unsigned long addr, unsigned long data)
488 {
489 #define WPC_DBRMODE 0x0d104008
490  static unsigned long first_call;
491 
492  if (!test_and_set_bit(0, &first_call)) {
493  /* Set WPC.DBRMODE to 0. This makes all debug events get
494  * delivered through RESVEC, i.e. into the handlers in entry.S.
495  * (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
496  * would normally be left set to 1, which makes debug events get
497  * delivered through DBRVEC, i.e. into the remote gdb's
498  * handlers. This prevents ptrace getting them, and confuses
499  * the remote gdb.) */
500  printk("DBRMODE set to 0 to permit native debugging\n");
501  poke_real_address_q(WPC_DBRMODE, 0);
502  }
503 
504  return sys_ptrace(request, pid, addr, data);
505 }
506 
507 static inline int audit_arch(void)
508 {
509  int arch = EM_SH;
510 
511 #ifdef CONFIG_64BIT
512  arch |= __AUDIT_ARCH_64BIT;
513 #endif
514 #ifdef CONFIG_CPU_LITTLE_ENDIAN
515  arch |= __AUDIT_ARCH_LE;
516 #endif
517 
518  return arch;
519 }
520 
521 asmlinkage long long do_syscall_trace_enter(struct pt_regs *regs)
522 {
523  long long ret = 0;
524 
525  secure_computing_strict(regs->regs[9]);
526 
527  if (test_thread_flag(TIF_SYSCALL_TRACE) &&
528  tracehook_report_syscall_entry(regs))
529  /*
530  * Tracing decided this syscall should not happen.
531  * We'll return a bogus call number to get an ENOSYS
532  * error, but leave the original number in regs->regs[0].
533  */
534  ret = -1LL;
535 
536  if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
537  trace_sys_enter(regs, regs->regs[9]);
538 
539  audit_syscall_entry(audit_arch(), regs->regs[1],
540  regs->regs[2], regs->regs[3],
541  regs->regs[4], regs->regs[5]);
542 
543  return ret ?: regs->regs[9];
544 }
545 
546 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
547 {
548  int step;
549 
550  audit_syscall_exit(regs);
551 
552  if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
553  trace_sys_exit(regs, regs->regs[9]);
554 
555  step = test_thread_flag(TIF_SINGLESTEP);
556  if (step || test_thread_flag(TIF_SYSCALL_TRACE))
557  tracehook_report_syscall_exit(regs, step);
558 }
559 
560 /* Called with interrupts disabled */
561 asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
562 {
563  /* This is called after a single step exception (DEBUGSS).
564  There is no need to change the PC, as it is a post-execution
565  exception, as entry.S does not do anything to the PC for DEBUGSS.
566  We need to clear the Single Step setting in SR to avoid
567  continually stepping. */
568  local_irq_enable();
569  regs->sr &= ~SR_SSTEP;
570  force_sig(SIGTRAP, current);
571 }
572 
573 /* Called with interrupts disabled */
574 BUILD_TRAP_HANDLER(breakpoint)
575 {
576  TRAP_HANDLER_DECL;
577 
578  /* We need to forward step the PC, to counteract the backstep done
579  in signal.c. */
580  local_irq_enable();
581  force_sig(SIGTRAP, current);
582  regs->pc += 4;
583 }
584 
585 /*
586  * Called by kernel/ptrace.c when detaching..
587  *
588  * Make sure single step bits etc are not set.
589  */
590 void ptrace_disable(struct task_struct *child)
591 {
592  user_disable_single_step(child);
593 }
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