Commit | Line | Data |
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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> | |
0013a854 | 26 | #include <asm/asm-offsets.h> |
1da177e4 LT |
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 | ||
481bed45 | 81 | long arch_ptrace(struct task_struct *child, long request, long addr, long data) |
1da177e4 | 82 | { |
1da177e4 LT |
83 | long ret; |
84 | #ifdef DEBUG_PTRACE | |
85 | long oaddr=addr, odata=data; | |
86 | #endif | |
87 | ||
1da177e4 LT |
88 | switch (request) { |
89 | case PTRACE_PEEKTEXT: /* read word at location addr. */ | |
90 | case PTRACE_PEEKDATA: { | |
91 | int copied; | |
92 | ||
93 | #ifdef __LP64__ | |
a3ea84fa | 94 | if (__is_compat_task(child)) { |
1da177e4 LT |
95 | unsigned int tmp; |
96 | ||
97 | addr &= 0xffffffffL; | |
98 | copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); | |
99 | ret = -EIO; | |
100 | if (copied != sizeof(tmp)) | |
101 | goto out_tsk; | |
102 | ret = put_user(tmp,(unsigned int *) data); | |
103 | DBG("sys_ptrace(PEEK%s, %d, %lx, %lx) returning %ld, data %x\n", | |
104 | request == PTRACE_PEEKTEXT ? "TEXT" : "DATA", | |
105 | pid, oaddr, odata, ret, tmp); | |
106 | } | |
107 | else | |
108 | #endif | |
109 | { | |
110 | unsigned long tmp; | |
111 | ||
112 | copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); | |
113 | ret = -EIO; | |
114 | if (copied != sizeof(tmp)) | |
115 | goto out_tsk; | |
116 | ret = put_user(tmp,(unsigned long *) data); | |
117 | } | |
118 | goto out_tsk; | |
119 | } | |
120 | ||
121 | /* when I and D space are separate, this will have to be fixed. */ | |
122 | case PTRACE_POKETEXT: /* write the word at location addr. */ | |
123 | case PTRACE_POKEDATA: | |
124 | ret = 0; | |
125 | #ifdef __LP64__ | |
a3ea84fa | 126 | if (__is_compat_task(child)) { |
1da177e4 LT |
127 | unsigned int tmp = (unsigned int)data; |
128 | DBG("sys_ptrace(POKE%s, %d, %lx, %lx)\n", | |
129 | request == PTRACE_POKETEXT ? "TEXT" : "DATA", | |
130 | pid, oaddr, odata); | |
131 | addr &= 0xffffffffL; | |
132 | if (access_process_vm(child, addr, &tmp, sizeof(tmp), 1) == sizeof(tmp)) | |
133 | goto out_tsk; | |
134 | } | |
135 | else | |
136 | #endif | |
137 | { | |
138 | if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data)) | |
139 | goto out_tsk; | |
140 | } | |
141 | ret = -EIO; | |
142 | goto out_tsk; | |
143 | ||
144 | /* Read the word at location addr in the USER area. For ptraced | |
145 | processes, the kernel saves all regs on a syscall. */ | |
146 | case PTRACE_PEEKUSR: { | |
147 | ret = -EIO; | |
148 | #ifdef __LP64__ | |
a3ea84fa | 149 | if (__is_compat_task(child)) { |
1da177e4 LT |
150 | unsigned int tmp; |
151 | ||
152 | if (addr & (sizeof(int)-1)) | |
153 | goto out_tsk; | |
154 | if ((addr = translate_usr_offset(addr)) < 0) | |
155 | goto out_tsk; | |
156 | ||
157 | tmp = *(unsigned int *) ((char *) task_regs(child) + addr); | |
158 | ret = put_user(tmp, (unsigned int *) data); | |
159 | DBG("sys_ptrace(PEEKUSR, %d, %lx, %lx) returning %ld, addr %lx, data %x\n", | |
160 | pid, oaddr, odata, ret, addr, tmp); | |
161 | } | |
162 | else | |
163 | #endif | |
164 | { | |
165 | unsigned long tmp; | |
166 | ||
167 | if ((addr & (sizeof(long)-1)) || (unsigned long) addr >= sizeof(struct pt_regs)) | |
168 | goto out_tsk; | |
169 | tmp = *(unsigned long *) ((char *) task_regs(child) + addr); | |
170 | ret = put_user(tmp, (unsigned long *) data); | |
171 | } | |
172 | goto out_tsk; | |
173 | } | |
174 | ||
175 | /* Write the word at location addr in the USER area. This will need | |
176 | to change when the kernel no longer saves all regs on a syscall. | |
177 | FIXME. There is a problem at the moment in that r3-r18 are only | |
178 | saved if the process is ptraced on syscall entry, and even then | |
179 | those values are overwritten by actual register values on syscall | |
180 | exit. */ | |
181 | case PTRACE_POKEUSR: | |
182 | ret = -EIO; | |
183 | /* Some register values written here may be ignored in | |
184 | * entry.S:syscall_restore_rfi; e.g. iaoq is written with | |
185 | * r31/r31+4, and not with the values in pt_regs. | |
186 | */ | |
187 | /* PT_PSW=0, so this is valid for 32 bit processes under 64 | |
188 | * bit kernels. | |
189 | */ | |
190 | if (addr == PT_PSW) { | |
191 | /* PT_PSW=0, so this is valid for 32 bit processes | |
192 | * under 64 bit kernels. | |
193 | * | |
194 | * Allow writing to Nullify, Divide-step-correction, | |
195 | * and carry/borrow bits. | |
196 | * BEWARE, if you set N, and then single step, it won't | |
197 | * stop on the nullified instruction. | |
198 | */ | |
199 | DBG("sys_ptrace(POKEUSR, %d, %lx, %lx)\n", | |
200 | pid, oaddr, odata); | |
201 | data &= USER_PSW_BITS; | |
202 | task_regs(child)->gr[0] &= ~USER_PSW_BITS; | |
203 | task_regs(child)->gr[0] |= data; | |
204 | ret = 0; | |
205 | goto out_tsk; | |
206 | } | |
207 | #ifdef __LP64__ | |
a3ea84fa | 208 | if (__is_compat_task(child)) { |
1da177e4 LT |
209 | if (addr & (sizeof(int)-1)) |
210 | goto out_tsk; | |
211 | if ((addr = translate_usr_offset(addr)) < 0) | |
212 | goto out_tsk; | |
213 | DBG("sys_ptrace(POKEUSR, %d, %lx, %lx) addr %lx\n", | |
214 | pid, oaddr, odata, addr); | |
215 | if (addr >= PT_FR0 && addr <= PT_FR31 + 4) { | |
216 | /* Special case, fp regs are 64 bits anyway */ | |
217 | *(unsigned int *) ((char *) task_regs(child) + addr) = data; | |
218 | ret = 0; | |
219 | } | |
220 | else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) || | |
221 | addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 || | |
222 | addr == PT_SAR+4) { | |
223 | /* Zero the top 32 bits */ | |
224 | *(unsigned int *) ((char *) task_regs(child) + addr - 4) = 0; | |
225 | *(unsigned int *) ((char *) task_regs(child) + addr) = data; | |
226 | ret = 0; | |
227 | } | |
228 | goto out_tsk; | |
229 | } | |
230 | else | |
231 | #endif | |
232 | { | |
233 | if ((addr & (sizeof(long)-1)) || (unsigned long) addr >= sizeof(struct pt_regs)) | |
234 | goto out_tsk; | |
235 | if ((addr >= PT_GR1 && addr <= PT_GR31) || | |
236 | addr == PT_IAOQ0 || addr == PT_IAOQ1 || | |
237 | (addr >= PT_FR0 && addr <= PT_FR31 + 4) || | |
238 | addr == PT_SAR) { | |
239 | *(unsigned long *) ((char *) task_regs(child) + addr) = data; | |
240 | ret = 0; | |
241 | } | |
242 | goto out_tsk; | |
243 | } | |
244 | ||
245 | case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ | |
246 | case PTRACE_CONT: | |
247 | ret = -EIO; | |
248 | DBG("sys_ptrace(%s)\n", | |
249 | request == PTRACE_SYSCALL ? "SYSCALL" : "CONT"); | |
7ed20e1a | 250 | if (!valid_signal(data)) |
1da177e4 LT |
251 | goto out_tsk; |
252 | child->ptrace &= ~(PT_SINGLESTEP|PT_BLOCKSTEP); | |
253 | if (request == PTRACE_SYSCALL) { | |
254 | set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
255 | } else { | |
256 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
257 | } | |
258 | child->exit_code = data; | |
259 | goto out_wake_notrap; | |
260 | ||
261 | case PTRACE_KILL: | |
262 | /* | |
263 | * make the child exit. Best I can do is send it a | |
264 | * sigkill. perhaps it should be put in the status | |
265 | * that it wants to exit. | |
266 | */ | |
83aceb5b | 267 | ret = 0; |
1da177e4 LT |
268 | DBG("sys_ptrace(KILL)\n"); |
269 | if (child->exit_state == EXIT_ZOMBIE) /* already dead */ | |
270 | goto out_tsk; | |
271 | child->exit_code = SIGKILL; | |
272 | goto out_wake_notrap; | |
273 | ||
274 | case PTRACE_SINGLEBLOCK: | |
275 | DBG("sys_ptrace(SINGLEBLOCK)\n"); | |
276 | ret = -EIO; | |
7ed20e1a | 277 | if (!valid_signal(data)) |
1da177e4 LT |
278 | goto out_tsk; |
279 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
280 | child->ptrace &= ~PT_SINGLESTEP; | |
281 | child->ptrace |= PT_BLOCKSTEP; | |
282 | child->exit_code = data; | |
283 | ||
284 | /* Enable taken branch trap. */ | |
285 | pa_psw(child)->r = 0; | |
286 | pa_psw(child)->t = 1; | |
287 | pa_psw(child)->h = 0; | |
288 | pa_psw(child)->l = 0; | |
289 | goto out_wake; | |
290 | ||
291 | case PTRACE_SINGLESTEP: | |
292 | DBG("sys_ptrace(SINGLESTEP)\n"); | |
293 | ret = -EIO; | |
7ed20e1a | 294 | if (!valid_signal(data)) |
1da177e4 LT |
295 | goto out_tsk; |
296 | ||
297 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
298 | child->ptrace &= ~PT_BLOCKSTEP; | |
299 | child->ptrace |= PT_SINGLESTEP; | |
300 | child->exit_code = data; | |
301 | ||
302 | if (pa_psw(child)->n) { | |
303 | struct siginfo si; | |
304 | ||
305 | /* Nullified, just crank over the queue. */ | |
306 | task_regs(child)->iaoq[0] = task_regs(child)->iaoq[1]; | |
307 | task_regs(child)->iasq[0] = task_regs(child)->iasq[1]; | |
308 | task_regs(child)->iaoq[1] = task_regs(child)->iaoq[0] + 4; | |
309 | pa_psw(child)->n = 0; | |
310 | pa_psw(child)->x = 0; | |
311 | pa_psw(child)->y = 0; | |
312 | pa_psw(child)->z = 0; | |
313 | pa_psw(child)->b = 0; | |
314 | ptrace_disable(child); | |
315 | /* Don't wake up the child, but let the | |
316 | parent know something happened. */ | |
317 | si.si_code = TRAP_TRACE; | |
318 | si.si_addr = (void __user *) (task_regs(child)->iaoq[0] & ~3); | |
319 | si.si_signo = SIGTRAP; | |
320 | si.si_errno = 0; | |
321 | force_sig_info(SIGTRAP, &si, child); | |
322 | //notify_parent(child, SIGCHLD); | |
323 | //ret = 0; | |
324 | goto out_wake; | |
325 | } | |
326 | ||
327 | /* Enable recovery counter traps. The recovery counter | |
328 | * itself will be set to zero on a task switch. If the | |
329 | * task is suspended on a syscall then the syscall return | |
330 | * path will overwrite the recovery counter with a suitable | |
331 | * value such that it traps once back in user space. We | |
332 | * disable interrupts in the childs PSW here also, to avoid | |
333 | * interrupts while the recovery counter is decrementing. | |
334 | */ | |
335 | pa_psw(child)->r = 1; | |
336 | pa_psw(child)->t = 0; | |
337 | pa_psw(child)->h = 0; | |
338 | pa_psw(child)->l = 0; | |
339 | /* give it a chance to run. */ | |
340 | goto out_wake; | |
341 | ||
342 | case PTRACE_DETACH: | |
343 | ret = ptrace_detach(child, data); | |
344 | goto out_tsk; | |
345 | ||
346 | case PTRACE_GETEVENTMSG: | |
347 | ret = put_user(child->ptrace_message, (unsigned int __user *) data); | |
83aceb5b | 348 | goto out_tsk; |
1da177e4 LT |
349 | |
350 | default: | |
351 | ret = ptrace_request(child, request, addr, data); | |
83aceb5b | 352 | goto out_tsk; |
1da177e4 LT |
353 | } |
354 | ||
355 | out_wake_notrap: | |
356 | ptrace_disable(child); | |
357 | out_wake: | |
358 | wake_up_process(child); | |
359 | ret = 0; | |
360 | out_tsk: | |
481bed45 | 361 | DBG("arch_ptrace(%ld, %d, %lx, %lx) returning %ld\n", |
1da177e4 LT |
362 | request, pid, oaddr, odata, ret); |
363 | return ret; | |
364 | } | |
365 | ||
366 | void syscall_trace(void) | |
367 | { | |
368 | if (!test_thread_flag(TIF_SYSCALL_TRACE)) | |
369 | return; | |
370 | if (!(current->ptrace & PT_PTRACED)) | |
371 | return; | |
372 | ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) | |
373 | ? 0x80 : 0)); | |
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 | } |