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ptrace.c
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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 - 2007 Tensilica Inc.
8  *
9  * Joe Taylor <[email protected], [email protected]>
10  * Chris Zankel <[email protected]>
11  * Scott Foehner<[email protected]>,
12  * Kevin Chea
13  * Marc Gauthier<[email protected]> <[email protected]>
14  */
15 
16 #include <linux/kernel.h>
17 #include <linux/sched.h>
18 #include <linux/mm.h>
19 #include <linux/errno.h>
20 #include <linux/ptrace.h>
21 #include <linux/smp.h>
22 #include <linux/security.h>
23 #include <linux/signal.h>
24 
25 #include <asm/pgtable.h>
26 #include <asm/page.h>
27 #include <asm/uaccess.h>
28 #include <asm/ptrace.h>
29 #include <asm/elf.h>
30 #include <asm/coprocessor.h>
31 
32 
33 void user_enable_single_step(struct task_struct *child)
34 {
35  child->ptrace |= PT_SINGLESTEP;
36 }
37 
38 void user_disable_single_step(struct task_struct *child)
39 {
40  child->ptrace &= ~PT_SINGLESTEP;
41 }
42 
43 /*
44  * Called by kernel/ptrace.c when detaching to disable single stepping.
45  */
46 
47 void ptrace_disable(struct task_struct *child)
48 {
49  /* Nothing to do.. */
50 }
51 
52 int ptrace_getregs(struct task_struct *child, void __user *uregs)
53 {
54  struct pt_regs *regs = task_pt_regs(child);
55  xtensa_gregset_t __user *gregset = uregs;
56  unsigned long wm = regs->wmask;
57  unsigned long wb = regs->windowbase;
58  int live, i;
59 
60  if (!access_ok(VERIFY_WRITE, uregs, sizeof(xtensa_gregset_t)))
61  return -EIO;
62 
63  __put_user(regs->pc, &gregset->pc);
64  __put_user(regs->ps & ~(1 << PS_EXCM_BIT), &gregset->ps);
65  __put_user(regs->lbeg, &gregset->lbeg);
66  __put_user(regs->lend, &gregset->lend);
67  __put_user(regs->lcount, &gregset->lcount);
68  __put_user(regs->windowstart, &gregset->windowstart);
69  __put_user(regs->windowbase, &gregset->windowbase);
70 
71  live = (wm & 2) ? 4 : (wm & 4) ? 8 : (wm & 8) ? 12 : 16;
72 
73  for (i = 0; i < live; i++)
74  __put_user(regs->areg[i],gregset->a+((wb*4+i)%XCHAL_NUM_AREGS));
75  for (i = XCHAL_NUM_AREGS - (wm >> 4) * 4; i < XCHAL_NUM_AREGS; i++)
76  __put_user(regs->areg[i],gregset->a+((wb*4+i)%XCHAL_NUM_AREGS));
77 
78  return 0;
79 }
80 
81 int ptrace_setregs(struct task_struct *child, void __user *uregs)
82 {
83  struct pt_regs *regs = task_pt_regs(child);
84  xtensa_gregset_t *gregset = uregs;
85  const unsigned long ps_mask = PS_CALLINC_MASK | PS_OWB_MASK;
86  unsigned long ps;
87  unsigned long wb;
88 
89  if (!access_ok(VERIFY_WRITE, uregs, sizeof(xtensa_gregset_t)))
90  return -EIO;
91 
92  __get_user(regs->pc, &gregset->pc);
93  __get_user(ps, &gregset->ps);
94  __get_user(regs->lbeg, &gregset->lbeg);
95  __get_user(regs->lend, &gregset->lend);
96  __get_user(regs->lcount, &gregset->lcount);
97  __get_user(regs->windowstart, &gregset->windowstart);
98  __get_user(wb, &gregset->windowbase);
99 
100  regs->ps = (regs->ps & ~ps_mask) | (ps & ps_mask) | (1 << PS_EXCM_BIT);
101 
102  if (wb >= XCHAL_NUM_AREGS / 4)
103  return -EFAULT;
104 
105  regs->windowbase = wb;
106 
107  if (wb != 0 && __copy_from_user(regs->areg + XCHAL_NUM_AREGS - wb * 4,
108  gregset->a, wb * 16))
109  return -EFAULT;
110 
111  if (__copy_from_user(regs->areg, gregset->a + wb*4, (WSBITS-wb) * 16))
112  return -EFAULT;
113 
114  return 0;
115 }
116 
117 
118 int ptrace_getxregs(struct task_struct *child, void __user *uregs)
119 {
120  struct pt_regs *regs = task_pt_regs(child);
121  struct thread_info *ti = task_thread_info(child);
122  elf_xtregs_t __user *xtregs = uregs;
123  int ret = 0;
124 
125  if (!access_ok(VERIFY_WRITE, uregs, sizeof(elf_xtregs_t)))
126  return -EIO;
127 
128 #if XTENSA_HAVE_COPROCESSORS
129  /* Flush all coprocessor registers to memory. */
130  coprocessor_flush_all(ti);
131  ret |= __copy_to_user(&xtregs->cp0, &ti->xtregs_cp,
132  sizeof(xtregs_coprocessor_t));
133 #endif
134  ret |= __copy_to_user(&xtregs->opt, &regs->xtregs_opt,
135  sizeof(xtregs->opt));
136  ret |= __copy_to_user(&xtregs->user,&ti->xtregs_user,
137  sizeof(xtregs->user));
138 
139  return ret ? -EFAULT : 0;
140 }
141 
142 int ptrace_setxregs(struct task_struct *child, void __user *uregs)
143 {
144  struct thread_info *ti = task_thread_info(child);
145  struct pt_regs *regs = task_pt_regs(child);
146  elf_xtregs_t *xtregs = uregs;
147  int ret = 0;
148 
149  if (!access_ok(VERIFY_READ, uregs, sizeof(elf_xtregs_t)))
150  return -EFAULT;
151 
152 #if XTENSA_HAVE_COPROCESSORS
153  /* Flush all coprocessors before we overwrite them. */
154  coprocessor_flush_all(ti);
155  coprocessor_release_all(ti);
156 
157  ret |= __copy_from_user(&ti->xtregs_cp, &xtregs->cp0,
158  sizeof(xtregs_coprocessor_t));
159 #endif
160  ret |= __copy_from_user(&regs->xtregs_opt, &xtregs->opt,
161  sizeof(xtregs->opt));
162  ret |= __copy_from_user(&ti->xtregs_user, &xtregs->user,
163  sizeof(xtregs->user));
164 
165  return ret ? -EFAULT : 0;
166 }
167 
168 int ptrace_peekusr(struct task_struct *child, long regno, long __user *ret)
169 {
170  struct pt_regs *regs;
171  unsigned long tmp;
172 
173  regs = task_pt_regs(child);
174  tmp = 0; /* Default return value. */
175 
176  switch(regno) {
177 
178  case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
179  tmp = regs->areg[regno - REG_AR_BASE];
180  break;
181 
182  case REG_A_BASE ... REG_A_BASE + 15:
183  tmp = regs->areg[regno - REG_A_BASE];
184  break;
185 
186  case REG_PC:
187  tmp = regs->pc;
188  break;
189 
190  case REG_PS:
191  /* Note: PS.EXCM is not set while user task is running;
192  * its being set in regs is for exception handling
193  * convenience. */
194  tmp = (regs->ps & ~(1 << PS_EXCM_BIT));
195  break;
196 
197  case REG_WB:
198  break; /* tmp = 0 */
199 
200  case REG_WS:
201  {
202  unsigned long wb = regs->windowbase;
203  unsigned long ws = regs->windowstart;
204  tmp = ((ws>>wb) | (ws<<(WSBITS-wb))) & ((1<<WSBITS)-1);
205  break;
206  }
207  case REG_LBEG:
208  tmp = regs->lbeg;
209  break;
210 
211  case REG_LEND:
212  tmp = regs->lend;
213  break;
214 
215  case REG_LCOUNT:
216  tmp = regs->lcount;
217  break;
218 
219  case REG_SAR:
220  tmp = regs->sar;
221  break;
222 
223  case SYSCALL_NR:
224  tmp = regs->syscall;
225  break;
226 
227  default:
228  return -EIO;
229  }
230  return put_user(tmp, ret);
231 }
232 
233 int ptrace_pokeusr(struct task_struct *child, long regno, long val)
234 {
235  struct pt_regs *regs;
236  regs = task_pt_regs(child);
237 
238  switch (regno) {
239  case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
240  regs->areg[regno - REG_AR_BASE] = val;
241  break;
242 
243  case REG_A_BASE ... REG_A_BASE + 15:
244  regs->areg[regno - REG_A_BASE] = val;
245  break;
246 
247  case REG_PC:
248  regs->pc = val;
249  break;
250 
251  case SYSCALL_NR:
252  regs->syscall = val;
253  break;
254 
255  default:
256  return -EIO;
257  }
258  return 0;
259 }
260 
261 long arch_ptrace(struct task_struct *child, long request,
262  unsigned long addr, unsigned long data)
263 {
264  int ret = -EPERM;
265  void __user *datap = (void __user *) data;
266 
267  switch (request) {
268  case PTRACE_PEEKTEXT: /* read word at location addr. */
269  case PTRACE_PEEKDATA:
270  ret = generic_ptrace_peekdata(child, addr, data);
271  break;
272 
273  case PTRACE_PEEKUSR: /* read register specified by addr. */
274  ret = ptrace_peekusr(child, addr, datap);
275  break;
276 
277  case PTRACE_POKETEXT: /* write the word at location addr. */
278  case PTRACE_POKEDATA:
279  ret = generic_ptrace_pokedata(child, addr, data);
280  break;
281 
282  case PTRACE_POKEUSR: /* write register specified by addr. */
283  ret = ptrace_pokeusr(child, addr, data);
284  break;
285 
286  case PTRACE_GETREGS:
287  ret = ptrace_getregs(child, datap);
288  break;
289 
290  case PTRACE_SETREGS:
291  ret = ptrace_setregs(child, datap);
292  break;
293 
294  case PTRACE_GETXTREGS:
295  ret = ptrace_getxregs(child, datap);
296  break;
297 
298  case PTRACE_SETXTREGS:
299  ret = ptrace_setxregs(child, datap);
300  break;
301 
302  default:
303  ret = ptrace_request(child, request, addr, data);
304  break;
305  }
306 
307  return ret;
308 }
309 
310 void do_syscall_trace(void)
311 {
312  /*
313  * The 0x80 provides a way for the tracing parent to distinguish
314  * between a syscall stop and SIGTRAP delivery
315  */
316  ptrace_notify(SIGTRAP|((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
317 
318  /*
319  * this isn't the same as continuing with a signal, but it will do
320  * for normal use. strace only continues with a signal if the
321  * stopping signal is not SIGTRAP. -brl
322  */
323  if (current->exit_code) {
324  send_sig(current->exit_code, current, 1);
325  current->exit_code = 0;
326  }
327 }
328 
329 void do_syscall_trace_enter(struct pt_regs *regs)
330 {
331  if (test_thread_flag(TIF_SYSCALL_TRACE)
332  && (current->ptrace & PT_PTRACED))
333  do_syscall_trace();
334 
335 #if 0
336  audit_syscall_entry(current, AUDIT_ARCH_XTENSA..);
337 #endif
338 }
339 
340 void do_syscall_trace_leave(struct pt_regs *regs)
341 {
342  if ((test_thread_flag(TIF_SYSCALL_TRACE))
343  && (current->ptrace & PT_PTRACED))
344  do_syscall_trace();
345 }
346 
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