[MIPS] N32: Make sure pointer is good before passing it to sys_waitid().
[linux-2.6] / arch / mips / kernel / ptrace.c
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (C) 1992 Ross Biro
7  * Copyright (C) Linus Torvalds
8  * Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle
9  * Copyright (C) 1996 David S. Miller
10  * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
11  * Copyright (C) 1999 MIPS Technologies, Inc.
12  * Copyright (C) 2000 Ulf Carlsson
13  *
14  * At this time Linux/MIPS64 only supports syscall tracing, even for 32-bit
15  * binaries.
16  */
17 #include <linux/config.h>
18 #include <linux/compiler.h>
19 #include <linux/kernel.h>
20 #include <linux/sched.h>
21 #include <linux/mm.h>
22 #include <linux/errno.h>
23 #include <linux/ptrace.h>
24 #include <linux/audit.h>
25 #include <linux/smp.h>
26 #include <linux/smp_lock.h>
27 #include <linux/user.h>
28 #include <linux/security.h>
29 #include <linux/signal.h>
30
31 #include <asm/byteorder.h>
32 #include <asm/cpu.h>
33 #include <asm/dsp.h>
34 #include <asm/fpu.h>
35 #include <asm/mipsregs.h>
36 #include <asm/mipsmtregs.h>
37 #include <asm/pgtable.h>
38 #include <asm/page.h>
39 #include <asm/system.h>
40 #include <asm/uaccess.h>
41 #include <asm/bootinfo.h>
42 #include <asm/reg.h>
43
44 /*
45  * Called by kernel/ptrace.c when detaching..
46  *
47  * Make sure single step bits etc are not set.
48  */
49 void ptrace_disable(struct task_struct *child)
50 {
51         /* Nothing to do.. */
52 }
53
54 /*
55  * Read a general register set.  We always use the 64-bit format, even
56  * for 32-bit kernels and for 32-bit processes on a 64-bit kernel.
57  * Registers are sign extended to fill the available space.
58  */
59 int ptrace_getregs (struct task_struct *child, __s64 __user *data)
60 {
61         struct pt_regs *regs;
62         int i;
63
64         if (!access_ok(VERIFY_WRITE, data, 38 * 8))
65                 return -EIO;
66
67         regs = task_pt_regs(child);
68
69         for (i = 0; i < 32; i++)
70                 __put_user (regs->regs[i], data + i);
71         __put_user (regs->lo, data + EF_LO - EF_R0);
72         __put_user (regs->hi, data + EF_HI - EF_R0);
73         __put_user (regs->cp0_epc, data + EF_CP0_EPC - EF_R0);
74         __put_user (regs->cp0_badvaddr, data + EF_CP0_BADVADDR - EF_R0);
75         __put_user (regs->cp0_status, data + EF_CP0_STATUS - EF_R0);
76         __put_user (regs->cp0_cause, data + EF_CP0_CAUSE - EF_R0);
77
78         return 0;
79 }
80
81 /*
82  * Write a general register set.  As for PTRACE_GETREGS, we always use
83  * the 64-bit format.  On a 32-bit kernel only the lower order half
84  * (according to endianness) will be used.
85  */
86 int ptrace_setregs (struct task_struct *child, __s64 __user *data)
87 {
88         struct pt_regs *regs;
89         int i;
90
91         if (!access_ok(VERIFY_READ, data, 38 * 8))
92                 return -EIO;
93
94         regs = task_pt_regs(child);
95
96         for (i = 0; i < 32; i++)
97                 __get_user (regs->regs[i], data + i);
98         __get_user (regs->lo, data + EF_LO - EF_R0);
99         __get_user (regs->hi, data + EF_HI - EF_R0);
100         __get_user (regs->cp0_epc, data + EF_CP0_EPC - EF_R0);
101
102         /* badvaddr, status, and cause may not be written.  */
103
104         return 0;
105 }
106
107 int ptrace_getfpregs (struct task_struct *child, __u32 __user *data)
108 {
109         int i;
110
111         if (!access_ok(VERIFY_WRITE, data, 33 * 8))
112                 return -EIO;
113
114         if (tsk_used_math(child)) {
115                 fpureg_t *fregs = get_fpu_regs(child);
116                 for (i = 0; i < 32; i++)
117                         __put_user (fregs[i], i + (__u64 __user *) data);
118         } else {
119                 for (i = 0; i < 32; i++)
120                         __put_user ((__u64) -1, i + (__u64 __user *) data);
121         }
122
123         if (cpu_has_fpu) {
124                 unsigned int flags, tmp;
125
126                 __put_user (child->thread.fpu.hard.fcr31, data + 64);
127
128                 preempt_disable();
129                 if (cpu_has_mipsmt) {
130                         unsigned int vpflags = dvpe();
131                         flags = read_c0_status();
132                         __enable_fpu();
133                         __asm__ __volatile__("cfc1\t%0,$0" : "=r" (tmp));
134                         write_c0_status(flags);
135                         evpe(vpflags);
136                 } else {
137                         flags = read_c0_status();
138                         __enable_fpu();
139                         __asm__ __volatile__("cfc1\t%0,$0" : "=r" (tmp));
140                         write_c0_status(flags);
141                 }
142                 preempt_enable();
143                 __put_user (tmp, data + 65);
144         } else {
145                 __put_user (child->thread.fpu.soft.fcr31, data + 64);
146                 __put_user ((__u32) 0, data + 65);
147         }
148
149         return 0;
150 }
151
152 int ptrace_setfpregs (struct task_struct *child, __u32 __user *data)
153 {
154         fpureg_t *fregs;
155         int i;
156
157         if (!access_ok(VERIFY_READ, data, 33 * 8))
158                 return -EIO;
159
160         fregs = get_fpu_regs(child);
161
162         for (i = 0; i < 32; i++)
163                 __get_user (fregs[i], i + (__u64 __user *) data);
164
165         if (cpu_has_fpu)
166                 __get_user (child->thread.fpu.hard.fcr31, data + 64);
167         else
168                 __get_user (child->thread.fpu.soft.fcr31, data + 64);
169
170         /* FIR may not be written.  */
171
172         return 0;
173 }
174
175 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
176 {
177         int ret;
178
179         switch (request) {
180         /* when I and D space are separate, these will need to be fixed. */
181         case PTRACE_PEEKTEXT: /* read word at location addr. */
182         case PTRACE_PEEKDATA: {
183                 unsigned long tmp;
184                 int copied;
185
186                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
187                 ret = -EIO;
188                 if (copied != sizeof(tmp))
189                         break;
190                 ret = put_user(tmp,(unsigned long __user *) data);
191                 break;
192         }
193
194         /* Read the word at location addr in the USER area. */
195         case PTRACE_PEEKUSR: {
196                 struct pt_regs *regs;
197                 unsigned long tmp = 0;
198
199                 regs = task_pt_regs(child);
200                 ret = 0;  /* Default return value. */
201
202                 switch (addr) {
203                 case 0 ... 31:
204                         tmp = regs->regs[addr];
205                         break;
206                 case FPR_BASE ... FPR_BASE + 31:
207                         if (tsk_used_math(child)) {
208                                 fpureg_t *fregs = get_fpu_regs(child);
209
210 #ifdef CONFIG_32BIT
211                                 /*
212                                  * The odd registers are actually the high
213                                  * order bits of the values stored in the even
214                                  * registers - unless we're using r2k_switch.S.
215                                  */
216                                 if (addr & 1)
217                                         tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32);
218                                 else
219                                         tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff);
220 #endif
221 #ifdef CONFIG_64BIT
222                                 tmp = fregs[addr - FPR_BASE];
223 #endif
224                         } else {
225                                 tmp = -1;       /* FP not yet used  */
226                         }
227                         break;
228                 case PC:
229                         tmp = regs->cp0_epc;
230                         break;
231                 case CAUSE:
232                         tmp = regs->cp0_cause;
233                         break;
234                 case BADVADDR:
235                         tmp = regs->cp0_badvaddr;
236                         break;
237                 case MMHI:
238                         tmp = regs->hi;
239                         break;
240                 case MMLO:
241                         tmp = regs->lo;
242                         break;
243                 case FPC_CSR:
244                         if (cpu_has_fpu)
245                                 tmp = child->thread.fpu.hard.fcr31;
246                         else
247                                 tmp = child->thread.fpu.soft.fcr31;
248                         break;
249                 case FPC_EIR: { /* implementation / version register */
250                         unsigned int flags;
251
252                         if (!cpu_has_fpu)
253                                 break;
254
255                         preempt_disable();
256                         if (cpu_has_mipsmt) {
257                                 unsigned int vpflags = dvpe();
258                                 flags = read_c0_status();
259                                 __enable_fpu();
260                                 __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
261                                 write_c0_status(flags);
262                                 evpe(vpflags);
263                         } else {
264                                 flags = read_c0_status();
265                                 __enable_fpu();
266                                 __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
267                                 write_c0_status(flags);
268                         }
269                         preempt_enable();
270                         break;
271                 }
272                 case DSP_BASE ... DSP_BASE + 5: {
273                         dspreg_t *dregs;
274
275                         if (!cpu_has_dsp) {
276                                 tmp = 0;
277                                 ret = -EIO;
278                                 goto out;
279                         }
280                         dregs = __get_dsp_regs(child);
281                         tmp = (unsigned long) (dregs[addr - DSP_BASE]);
282                         break;
283                 }
284                 case DSP_CONTROL:
285                         if (!cpu_has_dsp) {
286                                 tmp = 0;
287                                 ret = -EIO;
288                                 goto out;
289                         }
290                         tmp = child->thread.dsp.dspcontrol;
291                         break;
292                 default:
293                         tmp = 0;
294                         ret = -EIO;
295                         goto out;
296                 }
297                 ret = put_user(tmp, (unsigned long __user *) data);
298                 break;
299         }
300
301         /* when I and D space are separate, this will have to be fixed. */
302         case PTRACE_POKETEXT: /* write the word at location addr. */
303         case PTRACE_POKEDATA:
304                 ret = 0;
305                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
306                     == sizeof(data))
307                         break;
308                 ret = -EIO;
309                 break;
310
311         case PTRACE_POKEUSR: {
312                 struct pt_regs *regs;
313                 ret = 0;
314                 regs = task_pt_regs(child);
315
316                 switch (addr) {
317                 case 0 ... 31:
318                         regs->regs[addr] = data;
319                         break;
320                 case FPR_BASE ... FPR_BASE + 31: {
321                         fpureg_t *fregs = get_fpu_regs(child);
322
323                         if (!tsk_used_math(child)) {
324                                 /* FP not yet used  */
325                                 memset(&child->thread.fpu.hard, ~0,
326                                        sizeof(child->thread.fpu.hard));
327                                 child->thread.fpu.hard.fcr31 = 0;
328                         }
329 #ifdef CONFIG_32BIT
330                         /*
331                          * The odd registers are actually the high order bits
332                          * of the values stored in the even registers - unless
333                          * we're using r2k_switch.S.
334                          */
335                         if (addr & 1) {
336                                 fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff;
337                                 fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32;
338                         } else {
339                                 fregs[addr - FPR_BASE] &= ~0xffffffffLL;
340                                 fregs[addr - FPR_BASE] |= data;
341                         }
342 #endif
343 #ifdef CONFIG_64BIT
344                         fregs[addr - FPR_BASE] = data;
345 #endif
346                         break;
347                 }
348                 case PC:
349                         regs->cp0_epc = data;
350                         break;
351                 case MMHI:
352                         regs->hi = data;
353                         break;
354                 case MMLO:
355                         regs->lo = data;
356                         break;
357                 case FPC_CSR:
358                         if (cpu_has_fpu)
359                                 child->thread.fpu.hard.fcr31 = data;
360                         else
361                                 child->thread.fpu.soft.fcr31 = data;
362                         break;
363                 case DSP_BASE ... DSP_BASE + 5: {
364                         dspreg_t *dregs;
365
366                         if (!cpu_has_dsp) {
367                                 ret = -EIO;
368                                 break;
369                         }
370
371                         dregs = __get_dsp_regs(child);
372                         dregs[addr - DSP_BASE] = data;
373                         break;
374                 }
375                 case DSP_CONTROL:
376                         if (!cpu_has_dsp) {
377                                 ret = -EIO;
378                                 break;
379                         }
380                         child->thread.dsp.dspcontrol = data;
381                         break;
382                 default:
383                         /* The rest are not allowed. */
384                         ret = -EIO;
385                         break;
386                 }
387                 break;
388                 }
389
390         case PTRACE_GETREGS:
391                 ret = ptrace_getregs (child, (__u64 __user *) data);
392                 break;
393
394         case PTRACE_SETREGS:
395                 ret = ptrace_setregs (child, (__u64 __user *) data);
396                 break;
397
398         case PTRACE_GETFPREGS:
399                 ret = ptrace_getfpregs (child, (__u32 __user *) data);
400                 break;
401
402         case PTRACE_SETFPREGS:
403                 ret = ptrace_setfpregs (child, (__u32 __user *) data);
404                 break;
405
406         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
407         case PTRACE_CONT: { /* restart after signal. */
408                 ret = -EIO;
409                 if (!valid_signal(data))
410                         break;
411                 if (request == PTRACE_SYSCALL) {
412                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
413                 }
414                 else {
415                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
416                 }
417                 child->exit_code = data;
418                 wake_up_process(child);
419                 ret = 0;
420                 break;
421         }
422
423         /*
424          * make the child exit.  Best I can do is send it a sigkill.
425          * perhaps it should be put in the status that it wants to
426          * exit.
427          */
428         case PTRACE_KILL:
429                 ret = 0;
430                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
431                         break;
432                 child->exit_code = SIGKILL;
433                 wake_up_process(child);
434                 break;
435
436         case PTRACE_DETACH: /* detach a process that was attached. */
437                 ret = ptrace_detach(child, data);
438                 break;
439
440         case PTRACE_GET_THREAD_AREA:
441                 ret = put_user(task_thread_info(child)->tp_value,
442                                 (unsigned long __user *) data);
443                 break;
444
445         default:
446                 ret = ptrace_request(child, request, addr, data);
447                 break;
448         }
449  out:
450         return ret;
451 }
452
453 static inline int audit_arch(void)
454 {
455         int arch = EM_MIPS;
456 #ifdef CONFIG_64BIT
457         arch |=  __AUDIT_ARCH_64BIT;
458 #endif
459 #if defined(__LITTLE_ENDIAN)
460         arch |=  __AUDIT_ARCH_LE;
461 #endif
462         return arch;
463 }
464
465 /*
466  * Notification of system call entry/exit
467  * - triggered by current->work.syscall_trace
468  */
469 asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
470 {
471         if (unlikely(current->audit_context) && entryexit)
472                 audit_syscall_exit(current, AUDITSC_RESULT(regs->regs[2]),
473                                    regs->regs[2]);
474
475         if (!(current->ptrace & PT_PTRACED))
476                 goto out;
477         if (!test_thread_flag(TIF_SYSCALL_TRACE))
478                 goto out;
479
480         /* The 0x80 provides a way for the tracing parent to distinguish
481            between a syscall stop and SIGTRAP delivery */
482         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ?
483                                  0x80 : 0));
484
485         /*
486          * this isn't the same as continuing with a signal, but it will do
487          * for normal use.  strace only continues with a signal if the
488          * stopping signal is not SIGTRAP.  -brl
489          */
490         if (current->exit_code) {
491                 send_sig(current->exit_code, current, 1);
492                 current->exit_code = 0;
493         }
494  out:
495         if (unlikely(current->audit_context) && !entryexit)
496                 audit_syscall_entry(current, audit_arch(), regs->regs[2],
497                                     regs->regs[4], regs->regs[5],
498                                     regs->regs[6], regs->regs[7]);
499 }