xref: /linux/arch/mips/kernel/ptrace32.c (revision 858259cf7d1c443c836a2022b78cb281f0a9b95e)
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/compiler.h>
18 #include <linux/kernel.h>
19 #include <linux/sched.h>
20 #include <linux/mm.h>
21 #include <linux/errno.h>
22 #include <linux/ptrace.h>
23 #include <linux/smp.h>
24 #include <linux/smp_lock.h>
25 #include <linux/user.h>
26 #include <linux/security.h>
27 
28 #include <asm/cpu.h>
29 #include <asm/dsp.h>
30 #include <asm/fpu.h>
31 #include <asm/mipsregs.h>
32 #include <asm/mipsmtregs.h>
33 #include <asm/pgtable.h>
34 #include <asm/page.h>
35 #include <asm/system.h>
36 #include <asm/uaccess.h>
37 #include <asm/bootinfo.h>
38 
39 int ptrace_getregs (struct task_struct *child, __s64 __user *data);
40 int ptrace_setregs (struct task_struct *child, __s64 __user *data);
41 
42 int ptrace_getfpregs (struct task_struct *child, __u32 __user *data);
43 int ptrace_setfpregs (struct task_struct *child, __u32 __user *data);
44 
45 /*
46  * Tracing a 32-bit process with a 64-bit strace and vice versa will not
47  * work.  I don't know how to fix this.
48  */
49 asmlinkage int sys32_ptrace(int request, int pid, int addr, int data)
50 {
51 	struct task_struct *child;
52 	int ret;
53 
54 #if 0
55 	printk("ptrace(r=%d,pid=%d,addr=%08lx,data=%08lx)\n",
56 	       (int) request, (int) pid, (unsigned long) addr,
57 	       (unsigned long) data);
58 #endif
59 	lock_kernel();
60 	ret = -EPERM;
61 	if (request == PTRACE_TRACEME) {
62 		/* are we already being traced? */
63 		if (current->ptrace & PT_PTRACED)
64 			goto out;
65 		if ((ret = security_ptrace(current->parent, current)))
66 			goto out;
67 		/* set the ptrace bit in the process flags. */
68 		current->ptrace |= PT_PTRACED;
69 		ret = 0;
70 		goto out;
71 	}
72 	ret = -ESRCH;
73 	read_lock(&tasklist_lock);
74 	child = find_task_by_pid(pid);
75 	if (child)
76 		get_task_struct(child);
77 	read_unlock(&tasklist_lock);
78 	if (!child)
79 		goto out;
80 
81 	ret = -EPERM;
82 	if (pid == 1)		/* you may not mess with init */
83 		goto out_tsk;
84 
85 	if (request == PTRACE_ATTACH) {
86 		ret = ptrace_attach(child);
87 		goto out_tsk;
88 	}
89 
90 	ret = ptrace_check_attach(child, request == PTRACE_KILL);
91 	if (ret < 0)
92 		goto out_tsk;
93 
94 	switch (request) {
95 	/* when I and D space are separate, these will need to be fixed. */
96 	case PTRACE_PEEKTEXT: /* read word at location addr. */
97 	case PTRACE_PEEKDATA: {
98 		unsigned int tmp;
99 		int copied;
100 
101 		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
102 		ret = -EIO;
103 		if (copied != sizeof(tmp))
104 			break;
105 		ret = put_user(tmp, (unsigned int *) (unsigned long) data);
106 		break;
107 	}
108 
109 	/*
110 	 * Read 4 bytes of the other process' storage
111 	 *  data is a pointer specifying where the user wants the
112 	 *	4 bytes copied into
113 	 *  addr is a pointer in the user's storage that contains an 8 byte
114 	 *	address in the other process of the 4 bytes that is to be read
115 	 * (this is run in a 32-bit process looking at a 64-bit process)
116 	 * when I and D space are separate, these will need to be fixed.
117 	 */
118 	case PTRACE_PEEKTEXT_3264:
119 	case PTRACE_PEEKDATA_3264: {
120 		u32 tmp;
121 		int copied;
122 		u32 __user * addrOthers;
123 
124 		ret = -EIO;
125 
126 		/* Get the addr in the other process that we want to read */
127 		if (get_user(addrOthers, (u32 __user * __user *) (unsigned long) addr) != 0)
128 			break;
129 
130 		copied = access_process_vm(child, (u64)addrOthers, &tmp,
131 				sizeof(tmp), 0);
132 		if (copied != sizeof(tmp))
133 			break;
134 		ret = put_user(tmp, (u32 __user *) (unsigned long) data);
135 		break;
136 	}
137 
138 	/* Read the word at location addr in the USER area. */
139 	case PTRACE_PEEKUSR: {
140 		struct pt_regs *regs;
141 		unsigned int tmp;
142 
143 		regs = (struct pt_regs *) ((unsigned long) child->thread_info +
144 		       THREAD_SIZE - 32 - sizeof(struct pt_regs));
145 		ret = 0;  /* Default return value. */
146 
147 		switch (addr) {
148 		case 0 ... 31:
149 			tmp = regs->regs[addr];
150 			break;
151 		case FPR_BASE ... FPR_BASE + 31:
152 			if (tsk_used_math(child)) {
153 				fpureg_t *fregs = get_fpu_regs(child);
154 
155 				/*
156 				 * The odd registers are actually the high
157 				 * order bits of the values stored in the even
158 				 * registers - unless we're using r2k_switch.S.
159 				 */
160 				if (addr & 1)
161 					tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32);
162 				else
163 					tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff);
164 			} else {
165 				tmp = -1;	/* FP not yet used  */
166 			}
167 			break;
168 		case PC:
169 			tmp = regs->cp0_epc;
170 			break;
171 		case CAUSE:
172 			tmp = regs->cp0_cause;
173 			break;
174 		case BADVADDR:
175 			tmp = regs->cp0_badvaddr;
176 			break;
177 		case MMHI:
178 			tmp = regs->hi;
179 			break;
180 		case MMLO:
181 			tmp = regs->lo;
182 			break;
183 		case FPC_CSR:
184 			if (cpu_has_fpu)
185 				tmp = child->thread.fpu.hard.fcr31;
186 			else
187 				tmp = child->thread.fpu.soft.fcr31;
188 			break;
189 		case FPC_EIR: {	/* implementation / version register */
190 			unsigned int flags;
191 
192 			if (!cpu_has_fpu)
193 				break;
194 
195 			preempt_disable();
196 			if (cpu_has_mipsmt) {
197 				unsigned int vpflags = dvpe();
198 				flags = read_c0_status();
199 				__enable_fpu();
200 				__asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
201 				write_c0_status(flags);
202 				evpe(vpflags);
203 			} else {
204 				flags = read_c0_status();
205 				__enable_fpu();
206 				__asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
207 				write_c0_status(flags);
208 			}
209 			preempt_enable();
210 			break;
211 		}
212 		case DSP_BASE ... DSP_BASE + 5:
213 			if (!cpu_has_dsp) {
214 				tmp = 0;
215 				ret = -EIO;
216 				goto out_tsk;
217 			}
218 			if (child->thread.dsp.used_dsp) {
219 				dspreg_t *dregs = __get_dsp_regs(child);
220 				tmp = (unsigned long) (dregs[addr - DSP_BASE]);
221 			} else {
222 				tmp = -1;	/* DSP registers yet used  */
223 			}
224 			break;
225 		case DSP_CONTROL:
226 			if (!cpu_has_dsp) {
227 				tmp = 0;
228 				ret = -EIO;
229 				goto out_tsk;
230 			}
231 			tmp = child->thread.dsp.dspcontrol;
232 			break;
233 		default:
234 			tmp = 0;
235 			ret = -EIO;
236 			goto out_tsk;
237 		}
238 		ret = put_user(tmp, (unsigned *) (unsigned long) data);
239 		break;
240 	}
241 
242 	/* when I and D space are separate, this will have to be fixed. */
243 	case PTRACE_POKETEXT: /* write the word at location addr. */
244 	case PTRACE_POKEDATA:
245 		ret = 0;
246 		if (access_process_vm(child, addr, &data, sizeof(data), 1)
247 		    == sizeof(data))
248 			break;
249 		ret = -EIO;
250 		break;
251 
252 	/*
253 	 * Write 4 bytes into the other process' storage
254 	 *  data is the 4 bytes that the user wants written
255 	 *  addr is a pointer in the user's storage that contains an
256 	 *	8 byte address in the other process where the 4 bytes
257 	 *	that is to be written
258 	 * (this is run in a 32-bit process looking at a 64-bit process)
259 	 * when I and D space are separate, these will need to be fixed.
260 	 */
261 	case PTRACE_POKETEXT_3264:
262 	case PTRACE_POKEDATA_3264: {
263 		u32 __user * addrOthers;
264 
265 		/* Get the addr in the other process that we want to write into */
266 		ret = -EIO;
267 		if (get_user(addrOthers, (u32 __user * __user *) (unsigned long) addr) != 0)
268 			break;
269 		ret = 0;
270 		if (access_process_vm(child, (u64)addrOthers, &data,
271 					sizeof(data), 1) == sizeof(data))
272 			break;
273 		ret = -EIO;
274 		break;
275 	}
276 
277 	case PTRACE_POKEUSR: {
278 		struct pt_regs *regs;
279 		ret = 0;
280 		regs = (struct pt_regs *) ((unsigned long) child->thread_info +
281 		       THREAD_SIZE - 32 - sizeof(struct pt_regs));
282 
283 		switch (addr) {
284 		case 0 ... 31:
285 			regs->regs[addr] = data;
286 			break;
287 		case FPR_BASE ... FPR_BASE + 31: {
288 			fpureg_t *fregs = get_fpu_regs(child);
289 
290 			if (!tsk_used_math(child)) {
291 				/* FP not yet used  */
292 				memset(&child->thread.fpu.hard, ~0,
293 				       sizeof(child->thread.fpu.hard));
294 				child->thread.fpu.hard.fcr31 = 0;
295 			}
296 			/*
297 			 * The odd registers are actually the high order bits
298 			 * of the values stored in the even registers - unless
299 			 * we're using r2k_switch.S.
300 			 */
301 			if (addr & 1) {
302 				fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff;
303 				fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32;
304 			} else {
305 				fregs[addr - FPR_BASE] &= ~0xffffffffLL;
306 				/* Must cast, lest sign extension fill upper
307 				   bits!  */
308 				fregs[addr - FPR_BASE] |= (unsigned int)data;
309 			}
310 			break;
311 		}
312 		case PC:
313 			regs->cp0_epc = data;
314 			break;
315 		case MMHI:
316 			regs->hi = data;
317 			break;
318 		case MMLO:
319 			regs->lo = data;
320 			break;
321 		case FPC_CSR:
322 			if (cpu_has_fpu)
323 				child->thread.fpu.hard.fcr31 = data;
324 			else
325 				child->thread.fpu.soft.fcr31 = data;
326 			break;
327 		case DSP_BASE ... DSP_BASE + 5:
328 			if (!cpu_has_dsp) {
329 				ret = -EIO;
330 				break;
331 			}
332 
333 			dspreg_t *dregs = __get_dsp_regs(child);
334 			dregs[addr - DSP_BASE] = data;
335 			break;
336 		case DSP_CONTROL:
337 			if (!cpu_has_dsp) {
338 				ret = -EIO;
339 				break;
340 			}
341 			child->thread.dsp.dspcontrol = data;
342 			break;
343 		default:
344 			/* The rest are not allowed. */
345 			ret = -EIO;
346 			break;
347 		}
348 		break;
349 		}
350 
351 	case PTRACE_GETREGS:
352 		ret = ptrace_getregs (child, (__u64 __user *) (__u64) data);
353 		break;
354 
355 	case PTRACE_SETREGS:
356 		ret = ptrace_setregs (child, (__u64 __user *) (__u64) data);
357 		break;
358 
359 	case PTRACE_GETFPREGS:
360 		ret = ptrace_getfpregs (child, (__u32 __user *) (__u64) data);
361 		break;
362 
363 	case PTRACE_SETFPREGS:
364 		ret = ptrace_setfpregs (child, (__u32 __user *) (__u64) data);
365 		break;
366 
367 	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
368 	case PTRACE_CONT: { /* restart after signal. */
369 		ret = -EIO;
370 		if (!valid_signal(data))
371 			break;
372 		if (request == PTRACE_SYSCALL) {
373 			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
374 		}
375 		else {
376 			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
377 		}
378 		child->exit_code = data;
379 		wake_up_process(child);
380 		ret = 0;
381 		break;
382 	}
383 
384 	/*
385 	 * make the child exit.  Best I can do is send it a sigkill.
386 	 * perhaps it should be put in the status that it wants to
387 	 * exit.
388 	 */
389 	case PTRACE_KILL:
390 		ret = 0;
391 		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
392 			break;
393 		child->exit_code = SIGKILL;
394 		wake_up_process(child);
395 		break;
396 
397 	case PTRACE_GET_THREAD_AREA:
398 		ret = put_user(child->thread_info->tp_value,
399 				(unsigned int __user *) (unsigned long) data);
400 		break;
401 
402 	case PTRACE_DETACH: /* detach a process that was attached. */
403 		ret = ptrace_detach(child, data);
404 		break;
405 
406 	case PTRACE_GETEVENTMSG:
407 		ret = put_user(child->ptrace_message,
408 			       (unsigned int __user *) (unsigned long) data);
409 		break;
410 
411 	case PTRACE_GET_THREAD_AREA_3264:
412 		ret = put_user(child->thread_info->tp_value,
413 				(unsigned long __user *) (unsigned long) data);
414 		break;
415 
416 	default:
417 		ret = ptrace_request(child, request, addr, data);
418 		break;
419 	}
420 
421 out_tsk:
422 	put_task_struct(child);
423 out:
424 	unlock_kernel();
425 	return ret;
426 }
427