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ptrace.c
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1 /*
2  * arch/score/kernel/ptrace.c
3  *
4  * Score Processor version.
5  *
6  * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
7  * Chen Liqin <[email protected]>
8  * Lennox Wu <[email protected]>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, see the file COPYING, or write
22  * to the Free Software Foundation, Inc.,
23  * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
24  */
25 
26 #include <linux/elf.h>
27 #include <linux/kernel.h>
28 #include <linux/mm.h>
29 #include <linux/ptrace.h>
30 #include <linux/regset.h>
31 
32 #include <asm/uaccess.h>
33 
34 /*
35  * retrieve the contents of SCORE userspace general registers
36  */
37 static int genregs_get(struct task_struct *target,
38  const struct user_regset *regset,
39  unsigned int pos, unsigned int count,
40  void *kbuf, void __user *ubuf)
41 {
42  const struct pt_regs *regs = task_pt_regs(target);
43  int ret;
44 
45  /* skip 9 * sizeof(unsigned long) not use for pt_regs */
46  ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
47  0, offsetof(struct pt_regs, regs));
48 
49  /* r0 - r31, cel, ceh, sr0, sr1, sr2, epc, ema, psr, ecr, condition */
50  ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
51  regs->regs,
52  offsetof(struct pt_regs, regs),
53  offsetof(struct pt_regs, cp0_condition));
54 
55  if (!ret)
56  ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
57  sizeof(struct pt_regs), -1);
58 
59  return ret;
60 }
61 
62 /*
63  * update the contents of the SCORE userspace general registers
64  */
65 static int genregs_set(struct task_struct *target,
66  const struct user_regset *regset,
67  unsigned int pos, unsigned int count,
68  const void *kbuf, const void __user *ubuf)
69 {
70  struct pt_regs *regs = task_pt_regs(target);
71  int ret;
72 
73  /* skip 9 * sizeof(unsigned long) */
74  ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
75  0, offsetof(struct pt_regs, regs));
76 
77  /* r0 - r31, cel, ceh, sr0, sr1, sr2, epc, ema, psr, ecr, condition */
78  ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
79  regs->regs,
80  offsetof(struct pt_regs, regs),
81  offsetof(struct pt_regs, cp0_condition));
82 
83  if (!ret)
84  ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
85  sizeof(struct pt_regs), -1);
86 
87  return ret;
88 }
89 
90 /*
91  * Define the register sets available on the score7 under Linux
92  */
93 enum score7_regset {
94  REGSET_GENERAL,
95 };
96 
97 static const struct user_regset score7_regsets[] = {
98  [REGSET_GENERAL] = {
99  .core_note_type = NT_PRSTATUS,
100  .n = ELF_NGREG,
101  .size = sizeof(long),
102  .align = sizeof(long),
103  .get = genregs_get,
104  .set = genregs_set,
105  },
106 };
107 
108 static const struct user_regset_view user_score_native_view = {
109  .name = "score7",
110  .e_machine = EM_SCORE7,
111  .regsets = score7_regsets,
112  .n = ARRAY_SIZE(score7_regsets),
113 };
114 
115 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
116 {
117  return &user_score_native_view;
118 }
119 
120 static int is_16bitinsn(unsigned long insn)
121 {
122  if ((insn & INSN32_MASK) == INSN32_MASK)
123  return 0;
124  else
125  return 1;
126 }
127 
128 int
129 read_tsk_long(struct task_struct *child,
130  unsigned long addr, unsigned long *res)
131 {
132  int copied;
133 
134  copied = access_process_vm(child, addr, res, sizeof(*res), 0);
135 
136  return copied != sizeof(*res) ? -EIO : 0;
137 }
138 
139 int
140 read_tsk_short(struct task_struct *child,
141  unsigned long addr, unsigned short *res)
142 {
143  int copied;
144 
145  copied = access_process_vm(child, addr, res, sizeof(*res), 0);
146 
147  return copied != sizeof(*res) ? -EIO : 0;
148 }
149 
150 static int
151 write_tsk_short(struct task_struct *child,
152  unsigned long addr, unsigned short val)
153 {
154  int copied;
155 
156  copied = access_process_vm(child, addr, &val, sizeof(val), 1);
157 
158  return copied != sizeof(val) ? -EIO : 0;
159 }
160 
161 static int
162 write_tsk_long(struct task_struct *child,
163  unsigned long addr, unsigned long val)
164 {
165  int copied;
166 
167  copied = access_process_vm(child, addr, &val, sizeof(val), 1);
168 
169  return copied != sizeof(val) ? -EIO : 0;
170 }
171 
172 void user_enable_single_step(struct task_struct *child)
173 {
174  /* far_epc is the target of branch */
175  unsigned int epc, far_epc = 0;
176  unsigned long epc_insn, far_epc_insn;
177  int ninsn_type; /* next insn type 0=16b, 1=32b */
178  unsigned int tmp, tmp2;
179  struct pt_regs *regs = task_pt_regs(child);
180  child->thread.single_step = 1;
181  child->thread.ss_nextcnt = 1;
182  epc = regs->cp0_epc;
183 
184  read_tsk_long(child, epc, &epc_insn);
185 
186  if (is_16bitinsn(epc_insn)) {
187  if ((epc_insn & J16M) == J16) {
188  tmp = epc_insn & 0xFFE;
189  epc = (epc & 0xFFFFF000) | tmp;
190  } else if ((epc_insn & B16M) == B16) {
191  child->thread.ss_nextcnt = 2;
192  tmp = (epc_insn & 0xFF) << 1;
193  tmp = tmp << 23;
194  tmp = (unsigned int)((int) tmp >> 23);
195  far_epc = epc + tmp;
196  epc += 2;
197  } else if ((epc_insn & BR16M) == BR16) {
198  child->thread.ss_nextcnt = 2;
199  tmp = (epc_insn >> 4) & 0xF;
200  far_epc = regs->regs[tmp];
201  epc += 2;
202  } else
203  epc += 2;
204  } else {
205  if ((epc_insn & J32M) == J32) {
206  tmp = epc_insn & 0x03FFFFFE;
207  tmp2 = tmp & 0x7FFF;
208  tmp = (((tmp >> 16) & 0x3FF) << 15) | tmp2;
209  epc = (epc & 0xFFC00000) | tmp;
210  } else if ((epc_insn & B32M) == B32) {
211  child->thread.ss_nextcnt = 2;
212  tmp = epc_insn & 0x03FFFFFE; /* discard LK bit */
213  tmp2 = tmp & 0x3FF;
214  tmp = (((tmp >> 16) & 0x3FF) << 10) | tmp2; /* 20bit */
215  tmp = tmp << 12;
216  tmp = (unsigned int)((int) tmp >> 12);
217  far_epc = epc + tmp;
218  epc += 4;
219  } else if ((epc_insn & BR32M) == BR32) {
220  child->thread.ss_nextcnt = 2;
221  tmp = (epc_insn >> 16) & 0x1F;
222  far_epc = regs->regs[tmp];
223  epc += 4;
224  } else
225  epc += 4;
226  }
227 
228  if (child->thread.ss_nextcnt == 1) {
229  read_tsk_long(child, epc, &epc_insn);
230 
231  if (is_16bitinsn(epc_insn)) {
232  write_tsk_short(child, epc, SINGLESTEP16_INSN);
233  ninsn_type = 0;
234  } else {
235  write_tsk_long(child, epc, SINGLESTEP32_INSN);
236  ninsn_type = 1;
237  }
238 
239  if (ninsn_type == 0) { /* 16bits */
240  child->thread.insn1_type = 0;
241  child->thread.addr1 = epc;
242  /* the insn may have 32bit data */
243  child->thread.insn1 = (short)epc_insn;
244  } else {
245  child->thread.insn1_type = 1;
246  child->thread.addr1 = epc;
247  child->thread.insn1 = epc_insn;
248  }
249  } else {
250  /* branch! have two target child->thread.ss_nextcnt=2 */
251  read_tsk_long(child, epc, &epc_insn);
252  read_tsk_long(child, far_epc, &far_epc_insn);
253  if (is_16bitinsn(epc_insn)) {
254  write_tsk_short(child, epc, SINGLESTEP16_INSN);
255  ninsn_type = 0;
256  } else {
257  write_tsk_long(child, epc, SINGLESTEP32_INSN);
258  ninsn_type = 1;
259  }
260 
261  if (ninsn_type == 0) { /* 16bits */
262  child->thread.insn1_type = 0;
263  child->thread.addr1 = epc;
264  /* the insn may have 32bit data */
265  child->thread.insn1 = (short)epc_insn;
266  } else {
267  child->thread.insn1_type = 1;
268  child->thread.addr1 = epc;
269  child->thread.insn1 = epc_insn;
270  }
271 
272  if (is_16bitinsn(far_epc_insn)) {
273  write_tsk_short(child, far_epc, SINGLESTEP16_INSN);
274  ninsn_type = 0;
275  } else {
276  write_tsk_long(child, far_epc, SINGLESTEP32_INSN);
277  ninsn_type = 1;
278  }
279 
280  if (ninsn_type == 0) { /* 16bits */
281  child->thread.insn2_type = 0;
282  child->thread.addr2 = far_epc;
283  /* the insn may have 32bit data */
284  child->thread.insn2 = (short)far_epc_insn;
285  } else {
286  child->thread.insn2_type = 1;
287  child->thread.addr2 = far_epc;
288  child->thread.insn2 = far_epc_insn;
289  }
290  }
291 }
292 
293 void user_disable_single_step(struct task_struct *child)
294 {
295  if (child->thread.insn1_type == 0)
296  write_tsk_short(child, child->thread.addr1,
297  child->thread.insn1);
298 
299  if (child->thread.insn1_type == 1)
300  write_tsk_long(child, child->thread.addr1,
301  child->thread.insn1);
302 
303  if (child->thread.ss_nextcnt == 2) { /* branch */
304  if (child->thread.insn1_type == 0)
305  write_tsk_short(child, child->thread.addr1,
306  child->thread.insn1);
307  if (child->thread.insn1_type == 1)
308  write_tsk_long(child, child->thread.addr1,
309  child->thread.insn1);
310  if (child->thread.insn2_type == 0)
311  write_tsk_short(child, child->thread.addr2,
312  child->thread.insn2);
313  if (child->thread.insn2_type == 1)
314  write_tsk_long(child, child->thread.addr2,
315  child->thread.insn2);
316  }
317 
318  child->thread.single_step = 0;
319  child->thread.ss_nextcnt = 0;
320 }
321 
322 void ptrace_disable(struct task_struct *child)
323 {
324  user_disable_single_step(child);
325 }
326 
327 long
328 arch_ptrace(struct task_struct *child, long request,
329  unsigned long addr, unsigned long data)
330 {
331  int ret;
332  unsigned long __user *datap = (void __user *)data;
333 
334  switch (request) {
335  case PTRACE_GETREGS:
336  ret = copy_regset_to_user(child, &user_score_native_view,
337  REGSET_GENERAL,
338  0, sizeof(struct pt_regs),
339  datap);
340  break;
341 
342  case PTRACE_SETREGS:
343  ret = copy_regset_from_user(child, &user_score_native_view,
344  REGSET_GENERAL,
345  0, sizeof(struct pt_regs),
346  datap);
347  break;
348 
349  default:
350  ret = ptrace_request(child, request, addr, data);
351  break;
352  }
353 
354  return ret;
355 }
356 
357 /*
358  * Notification of system call entry/exit
359  * - triggered by current->work.syscall_trace
360  */
361 asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
362 {
363  if (!(current->ptrace & PT_PTRACED))
364  return;
365 
366  if (!test_thread_flag(TIF_SYSCALL_TRACE))
367  return;
368 
369  /* The 0x80 provides a way for the tracing parent to distinguish
370  between a syscall stop and SIGTRAP delivery. */
371  ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ?
372  0x80 : 0));
373 
374  /*
375  * this isn't the same as continuing with a signal, but it will do
376  * for normal use. strace only continues with a signal if the
377  * stopping signal is not SIGTRAP. -brl
378  */
379  if (current->exit_code) {
380  send_sig(current->exit_code, current, 1);
381  current->exit_code = 0;
382  }
383 }
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