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1da177e4 LT |
1 | /* |
2 | * Kernel support for the ptrace() and syscall tracing interfaces. | |
3 | * | |
4 | * Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc. | |
5 | * Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx> | |
6 | * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org> | |
7 | */ | |
8 | ||
9 | #include <linux/kernel.h> | |
10 | #include <linux/sched.h> | |
11 | #include <linux/mm.h> | |
12 | #include <linux/smp.h> | |
13 | #include <linux/smp_lock.h> | |
14 | #include <linux/errno.h> | |
15 | #include <linux/ptrace.h> | |
16 | #include <linux/user.h> | |
17 | #include <linux/personality.h> | |
18 | #include <linux/security.h> | |
19 | #include <linux/compat.h> | |
7ed20e1a | 20 | #include <linux/signal.h> |
1da177e4 LT |
21 | |
22 | #include <asm/uaccess.h> | |
23 | #include <asm/pgtable.h> | |
24 | #include <asm/system.h> | |
25 | #include <asm/processor.h> | |
26 | #include <asm/offsets.h> | |
27 | ||
28 | /* PSW bits we allow the debugger to modify */ | |
29 | #define USER_PSW_BITS (PSW_N | PSW_V | PSW_CB) | |
30 | ||
31 | #undef DEBUG_PTRACE | |
32 | ||
33 | #ifdef DEBUG_PTRACE | |
34 | #define DBG(x...) printk(x) | |
35 | #else | |
36 | #define DBG(x...) | |
37 | #endif | |
38 | ||
39 | #ifdef __LP64__ | |
40 | ||
41 | /* This function is needed to translate 32 bit pt_regs offsets in to | |
42 | * 64 bit pt_regs offsets. For example, a 32 bit gdb under a 64 bit kernel | |
43 | * will request offset 12 if it wants gr3, but the lower 32 bits of | |
44 | * the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4). | |
45 | * This code relies on a 32 bit pt_regs being comprised of 32 bit values | |
46 | * except for the fp registers which (a) are 64 bits, and (b) follow | |
47 | * the gr registers at the start of pt_regs. The 32 bit pt_regs should | |
48 | * be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[] | |
49 | * being 64 bit in both cases. | |
50 | */ | |
51 | ||
52 | static long translate_usr_offset(long offset) | |
53 | { | |
54 | if (offset < 0) | |
55 | return -1; | |
56 | else if (offset <= 32*4) /* gr[0..31] */ | |
57 | return offset * 2 + 4; | |
58 | else if (offset <= 32*4+32*8) /* gr[0..31] + fr[0..31] */ | |
59 | return offset + 32*4; | |
60 | else if (offset < sizeof(struct pt_regs)/2 + 32*4) | |
61 | return offset * 2 + 4 - 32*8; | |
62 | else | |
63 | return -1; | |
64 | } | |
65 | #endif | |
66 | ||
67 | /* | |
68 | * Called by kernel/ptrace.c when detaching.. | |
69 | * | |
70 | * Make sure single step bits etc are not set. | |
71 | */ | |
72 | void ptrace_disable(struct task_struct *child) | |
73 | { | |
74 | /* make sure the trap bits are not set */ | |
75 | pa_psw(child)->r = 0; | |
76 | pa_psw(child)->t = 0; | |
77 | pa_psw(child)->h = 0; | |
78 | pa_psw(child)->l = 0; | |
79 | } | |
80 | ||
81 | long sys_ptrace(long request, pid_t pid, long addr, long data) | |
82 | { | |
83 | struct task_struct *child; | |
84 | long ret; | |
85 | #ifdef DEBUG_PTRACE | |
86 | long oaddr=addr, odata=data; | |
87 | #endif | |
88 | ||
89 | lock_kernel(); | |
90 | ret = -EPERM; | |
91 | if (request == PTRACE_TRACEME) { | |
92 | /* are we already being traced? */ | |
93 | if (current->ptrace & PT_PTRACED) | |
94 | goto out; | |
95 | ||
96 | ret = security_ptrace(current->parent, current); | |
97 | if (ret) | |
98 | goto out; | |
99 | ||
100 | /* set the ptrace bit in the process flags. */ | |
101 | current->ptrace |= PT_PTRACED; | |
102 | ret = 0; | |
103 | goto out; | |
104 | } | |
105 | ||
106 | ret = -ESRCH; | |
107 | read_lock(&tasklist_lock); | |
108 | child = find_task_by_pid(pid); | |
109 | if (child) | |
110 | get_task_struct(child); | |
111 | read_unlock(&tasklist_lock); | |
112 | if (!child) | |
113 | goto out; | |
114 | ret = -EPERM; | |
115 | if (pid == 1) /* no messing around with init! */ | |
116 | goto out_tsk; | |
117 | ||
118 | if (request == PTRACE_ATTACH) { | |
119 | ret = ptrace_attach(child); | |
120 | goto out_tsk; | |
121 | } | |
122 | ||
123 | ret = ptrace_check_attach(child, request == PTRACE_KILL); | |
124 | if (ret < 0) | |
125 | goto out_tsk; | |
126 | ||
127 | switch (request) { | |
128 | case PTRACE_PEEKTEXT: /* read word at location addr. */ | |
129 | case PTRACE_PEEKDATA: { | |
130 | int copied; | |
131 | ||
132 | #ifdef __LP64__ | |
133 | if (is_compat_task(child)) { | |
134 | unsigned int tmp; | |
135 | ||
136 | addr &= 0xffffffffL; | |
137 | copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); | |
138 | ret = -EIO; | |
139 | if (copied != sizeof(tmp)) | |
140 | goto out_tsk; | |
141 | ret = put_user(tmp,(unsigned int *) data); | |
142 | DBG("sys_ptrace(PEEK%s, %d, %lx, %lx) returning %ld, data %x\n", | |
143 | request == PTRACE_PEEKTEXT ? "TEXT" : "DATA", | |
144 | pid, oaddr, odata, ret, tmp); | |
145 | } | |
146 | else | |
147 | #endif | |
148 | { | |
149 | unsigned long tmp; | |
150 | ||
151 | copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); | |
152 | ret = -EIO; | |
153 | if (copied != sizeof(tmp)) | |
154 | goto out_tsk; | |
155 | ret = put_user(tmp,(unsigned long *) data); | |
156 | } | |
157 | goto out_tsk; | |
158 | } | |
159 | ||
160 | /* when I and D space are separate, this will have to be fixed. */ | |
161 | case PTRACE_POKETEXT: /* write the word at location addr. */ | |
162 | case PTRACE_POKEDATA: | |
163 | ret = 0; | |
164 | #ifdef __LP64__ | |
165 | if (is_compat_task(child)) { | |
166 | unsigned int tmp = (unsigned int)data; | |
167 | DBG("sys_ptrace(POKE%s, %d, %lx, %lx)\n", | |
168 | request == PTRACE_POKETEXT ? "TEXT" : "DATA", | |
169 | pid, oaddr, odata); | |
170 | addr &= 0xffffffffL; | |
171 | if (access_process_vm(child, addr, &tmp, sizeof(tmp), 1) == sizeof(tmp)) | |
172 | goto out_tsk; | |
173 | } | |
174 | else | |
175 | #endif | |
176 | { | |
177 | if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data)) | |
178 | goto out_tsk; | |
179 | } | |
180 | ret = -EIO; | |
181 | goto out_tsk; | |
182 | ||
183 | /* Read the word at location addr in the USER area. For ptraced | |
184 | processes, the kernel saves all regs on a syscall. */ | |
185 | case PTRACE_PEEKUSR: { | |
186 | ret = -EIO; | |
187 | #ifdef __LP64__ | |
188 | if (is_compat_task(child)) { | |
189 | unsigned int tmp; | |
190 | ||
191 | if (addr & (sizeof(int)-1)) | |
192 | goto out_tsk; | |
193 | if ((addr = translate_usr_offset(addr)) < 0) | |
194 | goto out_tsk; | |
195 | ||
196 | tmp = *(unsigned int *) ((char *) task_regs(child) + addr); | |
197 | ret = put_user(tmp, (unsigned int *) data); | |
198 | DBG("sys_ptrace(PEEKUSR, %d, %lx, %lx) returning %ld, addr %lx, data %x\n", | |
199 | pid, oaddr, odata, ret, addr, tmp); | |
200 | } | |
201 | else | |
202 | #endif | |
203 | { | |
204 | unsigned long tmp; | |
205 | ||
206 | if ((addr & (sizeof(long)-1)) || (unsigned long) addr >= sizeof(struct pt_regs)) | |
207 | goto out_tsk; | |
208 | tmp = *(unsigned long *) ((char *) task_regs(child) + addr); | |
209 | ret = put_user(tmp, (unsigned long *) data); | |
210 | } | |
211 | goto out_tsk; | |
212 | } | |
213 | ||
214 | /* Write the word at location addr in the USER area. This will need | |
215 | to change when the kernel no longer saves all regs on a syscall. | |
216 | FIXME. There is a problem at the moment in that r3-r18 are only | |
217 | saved if the process is ptraced on syscall entry, and even then | |
218 | those values are overwritten by actual register values on syscall | |
219 | exit. */ | |
220 | case PTRACE_POKEUSR: | |
221 | ret = -EIO; | |
222 | /* Some register values written here may be ignored in | |
223 | * entry.S:syscall_restore_rfi; e.g. iaoq is written with | |
224 | * r31/r31+4, and not with the values in pt_regs. | |
225 | */ | |
226 | /* PT_PSW=0, so this is valid for 32 bit processes under 64 | |
227 | * bit kernels. | |
228 | */ | |
229 | if (addr == PT_PSW) { | |
230 | /* PT_PSW=0, so this is valid for 32 bit processes | |
231 | * under 64 bit kernels. | |
232 | * | |
233 | * Allow writing to Nullify, Divide-step-correction, | |
234 | * and carry/borrow bits. | |
235 | * BEWARE, if you set N, and then single step, it won't | |
236 | * stop on the nullified instruction. | |
237 | */ | |
238 | DBG("sys_ptrace(POKEUSR, %d, %lx, %lx)\n", | |
239 | pid, oaddr, odata); | |
240 | data &= USER_PSW_BITS; | |
241 | task_regs(child)->gr[0] &= ~USER_PSW_BITS; | |
242 | task_regs(child)->gr[0] |= data; | |
243 | ret = 0; | |
244 | goto out_tsk; | |
245 | } | |
246 | #ifdef __LP64__ | |
247 | if (is_compat_task(child)) { | |
248 | if (addr & (sizeof(int)-1)) | |
249 | goto out_tsk; | |
250 | if ((addr = translate_usr_offset(addr)) < 0) | |
251 | goto out_tsk; | |
252 | DBG("sys_ptrace(POKEUSR, %d, %lx, %lx) addr %lx\n", | |
253 | pid, oaddr, odata, addr); | |
254 | if (addr >= PT_FR0 && addr <= PT_FR31 + 4) { | |
255 | /* Special case, fp regs are 64 bits anyway */ | |
256 | *(unsigned int *) ((char *) task_regs(child) + addr) = data; | |
257 | ret = 0; | |
258 | } | |
259 | else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) || | |
260 | addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 || | |
261 | addr == PT_SAR+4) { | |
262 | /* Zero the top 32 bits */ | |
263 | *(unsigned int *) ((char *) task_regs(child) + addr - 4) = 0; | |
264 | *(unsigned int *) ((char *) task_regs(child) + addr) = data; | |
265 | ret = 0; | |
266 | } | |
267 | goto out_tsk; | |
268 | } | |
269 | else | |
270 | #endif | |
271 | { | |
272 | if ((addr & (sizeof(long)-1)) || (unsigned long) addr >= sizeof(struct pt_regs)) | |
273 | goto out_tsk; | |
274 | if ((addr >= PT_GR1 && addr <= PT_GR31) || | |
275 | addr == PT_IAOQ0 || addr == PT_IAOQ1 || | |
276 | (addr >= PT_FR0 && addr <= PT_FR31 + 4) || | |
277 | addr == PT_SAR) { | |
278 | *(unsigned long *) ((char *) task_regs(child) + addr) = data; | |
279 | ret = 0; | |
280 | } | |
281 | goto out_tsk; | |
282 | } | |
283 | ||
284 | case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ | |
285 | case PTRACE_CONT: | |
286 | ret = -EIO; | |
287 | DBG("sys_ptrace(%s)\n", | |
288 | request == PTRACE_SYSCALL ? "SYSCALL" : "CONT"); | |
7ed20e1a | 289 | if (!valid_signal(data)) |
1da177e4 LT |
290 | goto out_tsk; |
291 | child->ptrace &= ~(PT_SINGLESTEP|PT_BLOCKSTEP); | |
292 | if (request == PTRACE_SYSCALL) { | |
293 | set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
294 | } else { | |
295 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
296 | } | |
297 | child->exit_code = data; | |
298 | goto out_wake_notrap; | |
299 | ||
300 | case PTRACE_KILL: | |
301 | /* | |
302 | * make the child exit. Best I can do is send it a | |
303 | * sigkill. perhaps it should be put in the status | |
304 | * that it wants to exit. | |
305 | */ | |
306 | DBG("sys_ptrace(KILL)\n"); | |
307 | if (child->exit_state == EXIT_ZOMBIE) /* already dead */ | |
308 | goto out_tsk; | |
309 | child->exit_code = SIGKILL; | |
310 | goto out_wake_notrap; | |
311 | ||
312 | case PTRACE_SINGLEBLOCK: | |
313 | DBG("sys_ptrace(SINGLEBLOCK)\n"); | |
314 | ret = -EIO; | |
7ed20e1a | 315 | if (!valid_signal(data)) |
1da177e4 LT |
316 | goto out_tsk; |
317 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
318 | child->ptrace &= ~PT_SINGLESTEP; | |
319 | child->ptrace |= PT_BLOCKSTEP; | |
320 | child->exit_code = data; | |
321 | ||
322 | /* Enable taken branch trap. */ | |
323 | pa_psw(child)->r = 0; | |
324 | pa_psw(child)->t = 1; | |
325 | pa_psw(child)->h = 0; | |
326 | pa_psw(child)->l = 0; | |
327 | goto out_wake; | |
328 | ||
329 | case PTRACE_SINGLESTEP: | |
330 | DBG("sys_ptrace(SINGLESTEP)\n"); | |
331 | ret = -EIO; | |
7ed20e1a | 332 | if (!valid_signal(data)) |
1da177e4 LT |
333 | goto out_tsk; |
334 | ||
335 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
336 | child->ptrace &= ~PT_BLOCKSTEP; | |
337 | child->ptrace |= PT_SINGLESTEP; | |
338 | child->exit_code = data; | |
339 | ||
340 | if (pa_psw(child)->n) { | |
341 | struct siginfo si; | |
342 | ||
343 | /* Nullified, just crank over the queue. */ | |
344 | task_regs(child)->iaoq[0] = task_regs(child)->iaoq[1]; | |
345 | task_regs(child)->iasq[0] = task_regs(child)->iasq[1]; | |
346 | task_regs(child)->iaoq[1] = task_regs(child)->iaoq[0] + 4; | |
347 | pa_psw(child)->n = 0; | |
348 | pa_psw(child)->x = 0; | |
349 | pa_psw(child)->y = 0; | |
350 | pa_psw(child)->z = 0; | |
351 | pa_psw(child)->b = 0; | |
352 | ptrace_disable(child); | |
353 | /* Don't wake up the child, but let the | |
354 | parent know something happened. */ | |
355 | si.si_code = TRAP_TRACE; | |
356 | si.si_addr = (void __user *) (task_regs(child)->iaoq[0] & ~3); | |
357 | si.si_signo = SIGTRAP; | |
358 | si.si_errno = 0; | |
359 | force_sig_info(SIGTRAP, &si, child); | |
360 | //notify_parent(child, SIGCHLD); | |
361 | //ret = 0; | |
362 | goto out_wake; | |
363 | } | |
364 | ||
365 | /* Enable recovery counter traps. The recovery counter | |
366 | * itself will be set to zero on a task switch. If the | |
367 | * task is suspended on a syscall then the syscall return | |
368 | * path will overwrite the recovery counter with a suitable | |
369 | * value such that it traps once back in user space. We | |
370 | * disable interrupts in the childs PSW here also, to avoid | |
371 | * interrupts while the recovery counter is decrementing. | |
372 | */ | |
373 | pa_psw(child)->r = 1; | |
374 | pa_psw(child)->t = 0; | |
375 | pa_psw(child)->h = 0; | |
376 | pa_psw(child)->l = 0; | |
377 | /* give it a chance to run. */ | |
378 | goto out_wake; | |
379 | ||
380 | case PTRACE_DETACH: | |
381 | ret = ptrace_detach(child, data); | |
382 | goto out_tsk; | |
383 | ||
384 | case PTRACE_GETEVENTMSG: | |
385 | ret = put_user(child->ptrace_message, (unsigned int __user *) data); | |
386 | goto out_tsk; | |
387 | ||
388 | default: | |
389 | ret = ptrace_request(child, request, addr, data); | |
390 | goto out_tsk; | |
391 | } | |
392 | ||
393 | out_wake_notrap: | |
394 | ptrace_disable(child); | |
395 | out_wake: | |
396 | wake_up_process(child); | |
397 | ret = 0; | |
398 | out_tsk: | |
399 | put_task_struct(child); | |
400 | out: | |
401 | unlock_kernel(); | |
402 | DBG("sys_ptrace(%ld, %d, %lx, %lx) returning %ld\n", | |
403 | request, pid, oaddr, odata, ret); | |
404 | return ret; | |
405 | } | |
406 | ||
407 | void syscall_trace(void) | |
408 | { | |
409 | if (!test_thread_flag(TIF_SYSCALL_TRACE)) | |
410 | return; | |
411 | if (!(current->ptrace & PT_PTRACED)) | |
412 | return; | |
413 | ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) | |
414 | ? 0x80 : 0)); | |
415 | /* | |
416 | * this isn't the same as continuing with a signal, but it will do | |
417 | * for normal use. strace only continues with a signal if the | |
418 | * stopping signal is not SIGTRAP. -brl | |
419 | */ | |
420 | if (current->exit_code) { | |
421 | send_sig(current->exit_code, current, 1); | |
422 | current->exit_code = 0; | |
423 | } | |
424 | } |