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 */
13 #include <linux/config.h>
14 #include <linux/kernel.h>
15 #include <linux/sched.h>
16 #include <linux/mm.h>
17 #include <linux/errno.h>
18 #include <linux/ptrace.h>
19 #include <linux/smp.h>
20 #include <linux/smp_lock.h>
21 #include <linux/user.h>
22
23 #include <asm/mipsregs.h>
24 #include <asm/pgtable.h>
25 #include <asm/page.h>
26 #include <asm/system.h>
27 #include <asm/uaccess.h>
28 #include <asm/bootinfo.h>
29 #include <asm/cpu.h>
30 #include <asm/fpu.h>
31
32 /*
33 * Called by kernel/ptrace.c when detaching..
34 *
35 * Make sure single step bits etc are not set.
36 */
ptrace_disable(struct task_struct * child)37 void ptrace_disable(struct task_struct *child)
38 {
39 /* Nothing to do.. */
40 }
41
sys_ptrace(long request,long pid,long addr,long data)42 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
43 {
44 struct task_struct *child;
45 int ret;
46
47 lock_kernel();
48 #if 0
49 printk("ptrace(r=%d,pid=%d,addr=%08lx,data=%08lx)\n",
50 (int) request, (int) pid, (unsigned long) addr,
51 (unsigned long) data);
52 #endif
53 if (request == PTRACE_TRACEME) {
54 /* are we already being traced? */
55 if (current->ptrace & PT_PTRACED) {
56 ret = -EPERM;
57 goto out;
58 }
59 /* set the ptrace bit in the process flags. */
60 current->ptrace |= PT_PTRACED;
61 ret = 0;
62 goto out;
63 }
64 ret = -ESRCH;
65 read_lock(&tasklist_lock);
66 child = find_task_by_pid(pid);
67 if (child)
68 get_task_struct(child);
69 read_unlock(&tasklist_lock);
70 if (!child)
71 goto out;
72
73 ret = -EPERM;
74 if (pid == 1) /* you may not mess with init */
75 goto out_tsk;
76
77 if (request == PTRACE_ATTACH) {
78 ret = ptrace_attach(child);
79 goto out_tsk;
80 }
81
82 ret = ptrace_check_attach(child, request == PTRACE_KILL);
83 if (ret < 0)
84 goto out_tsk;
85
86 switch (request) {
87 case PTRACE_PEEKTEXT: /* read word at location addr. */
88 case PTRACE_PEEKDATA: {
89 unsigned long tmp;
90 int copied;
91
92 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
93 ret = -EIO;
94 if (copied != sizeof(tmp))
95 break;
96 ret = put_user(tmp,(unsigned long *) data);
97 break;
98 }
99
100 /* Read the word at location addr in the USER area. */
101 case PTRACE_PEEKUSR: {
102 struct pt_regs *regs;
103 unsigned long tmp;
104
105 regs = (struct pt_regs *) ((unsigned long) child +
106 KERNEL_STACK_SIZE - 32 - sizeof(struct pt_regs));
107 tmp = 0; /* Default return value. */
108
109 switch(addr) {
110 case 0 ... 31:
111 tmp = regs->regs[addr];
112 break;
113 case FPR_BASE ... FPR_BASE + 31:
114 if (child->used_math) {
115 unsigned long long *fregs = get_fpu_regs(child);
116 /*
117 * The odd registers are actually the high
118 * order bits of the values stored in the even
119 * registers - unless we're using r2k_switch.S.
120 */
121 if (addr & 1)
122 tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32);
123 else
124 tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff);
125 } else {
126 tmp = -1; /* FP not yet used */
127 }
128 break;
129 case PC:
130 tmp = regs->cp0_epc;
131 break;
132 case CAUSE:
133 tmp = regs->cp0_cause;
134 break;
135 case BADVADDR:
136 tmp = regs->cp0_badvaddr;
137 break;
138 case MMHI:
139 tmp = regs->hi;
140 break;
141 case MMLO:
142 tmp = regs->lo;
143 break;
144 case FPC_CSR:
145 if (!cpu_has_fpu)
146 tmp = child->thread.fpu.soft.sr;
147 else
148 tmp = child->thread.fpu.hard.control;
149 break;
150 case FPC_EIR: { /* implementation / version register */
151 unsigned long flags;
152
153 if (!cpu_has_fpu)
154 break;
155
156 __save_flags(flags);
157 __enable_fpu();
158 __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
159 __restore_flags(flags);
160 break;
161 }
162 default:
163 tmp = 0;
164 ret = -EIO;
165 goto out_tsk;
166 }
167 ret = put_user(tmp, (unsigned long *) data);
168 break;
169 }
170
171 case PTRACE_POKETEXT: /* write the word at location addr. */
172 case PTRACE_POKEDATA:
173 ret = 0;
174 if (access_process_vm(child, addr, &data, sizeof(data), 1)
175 == sizeof(data))
176 break;
177 ret = -EIO;
178 break;
179
180 case PTRACE_POKEUSR: {
181 struct pt_regs *regs;
182 ret = 0;
183 regs = (struct pt_regs *) ((unsigned long) child +
184 KERNEL_STACK_SIZE - 32 - sizeof(struct pt_regs));
185
186 switch (addr) {
187 case 0 ... 31:
188 regs->regs[addr] = data;
189 break;
190 case FPR_BASE ... FPR_BASE + 31: {
191 unsigned long long *fregs;
192 fregs = (unsigned long long *)get_fpu_regs(child);
193 if (!child->used_math) {
194 /* FP not yet used */
195 memset(&child->thread.fpu.hard, ~0,
196 sizeof(child->thread.fpu.hard));
197 child->thread.fpu.hard.control = 0;
198 }
199 /*
200 * The odd registers are actually the high order bits
201 * of the values stored in the even registers - unless
202 * we're using r2k_switch.S.
203 */
204 if (addr & 1) {
205 fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff;
206 fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32;
207 } else {
208 fregs[addr - FPR_BASE] &= ~0xffffffffLL;
209 fregs[addr - FPR_BASE] |= data;
210 }
211 break;
212 }
213 case PC:
214 regs->cp0_epc = data;
215 break;
216 case MMHI:
217 regs->hi = data;
218 break;
219 case MMLO:
220 regs->lo = data;
221 break;
222 case FPC_CSR:
223 if (!cpu_has_fpu)
224 child->thread.fpu.soft.sr = data;
225 else
226 child->thread.fpu.hard.control = data;
227 break;
228 default:
229 /* The rest are not allowed. */
230 ret = -EIO;
231 break;
232 }
233 break;
234 }
235
236 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
237 case PTRACE_CONT: { /* restart after signal. */
238 ret = -EIO;
239 if ((unsigned long) data > _NSIG)
240 break;
241 if (request == PTRACE_SYSCALL)
242 child->ptrace |= PT_TRACESYS;
243 else
244 child->ptrace &= ~PT_TRACESYS;
245 child->exit_code = data;
246 wake_up_process(child);
247 ret = 0;
248 break;
249 }
250
251 /*
252 * make the child exit. Best I can do is send it a sigkill.
253 * perhaps it should be put in the status that it wants to
254 * exit.
255 */
256 case PTRACE_KILL:
257 ret = 0;
258 if (child->state == TASK_ZOMBIE) /* already dead */
259 break;
260 child->exit_code = SIGKILL;
261 wake_up_process(child);
262 break;
263
264 case PTRACE_DETACH: /* detach a process that was attached. */
265 ret = ptrace_detach(child, data);
266 break;
267
268 case PTRACE_SETOPTIONS:
269 if (data & PTRACE_O_TRACESYSGOOD)
270 child->ptrace |= PT_TRACESYSGOOD;
271 else
272 child->ptrace &= ~PT_TRACESYSGOOD;
273 ret = 0;
274 break;
275
276 default:
277 ret = -EIO;
278 break;
279 }
280 out_tsk:
281 free_task_struct(child);
282 out:
283 unlock_kernel();
284 return ret;
285 }
286
syscall_trace(void)287 asmlinkage void syscall_trace(void)
288 {
289 if ((current->ptrace & (PT_PTRACED|PT_TRACESYS))
290 != (PT_PTRACED|PT_TRACESYS))
291 return;
292 /* The 0x80 provides a way for the tracing parent to distinguish
293 between a syscall stop and SIGTRAP delivery */
294 current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
295 ? 0x80 : 0);
296 current->state = TASK_STOPPED;
297 notify_parent(current, SIGCHLD);
298 schedule();
299 /*
300 * this isn't the same as continuing with a signal, but it will do
301 * for normal use. strace only continues with a signal if the
302 * stopping signal is not SIGTRAP. -brl
303 */
304 if (current->exit_code) {
305 send_sig(current->exit_code, current, 1);
306 current->exit_code = 0;
307 }
308 }
309