blob: 39060cbeb2a3e2acc45509fe8ea8303222bd17e3 [file] [log] [blame]
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -07001/*
2 * Copyright (C) 2004-2006 Atmel Corporation
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8#undef DEBUG
9#include <linux/kernel.h>
10#include <linux/sched.h>
11#include <linux/mm.h>
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070012#include <linux/ptrace.h>
13#include <linux/errno.h>
14#include <linux/user.h>
15#include <linux/security.h>
16#include <linux/unistd.h>
17#include <linux/notifier.h>
18
19#include <asm/traps.h>
20#include <asm/uaccess.h>
21#include <asm/ocd.h>
22#include <asm/mmu_context.h>
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -070023#include <linux/kdebug.h>
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070024
25static struct pt_regs *get_user_regs(struct task_struct *tsk)
26{
Roman Zippelc9f4f062007-05-09 02:35:16 -070027 return (struct pt_regs *)((unsigned long)task_stack_page(tsk) +
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070028 THREAD_SIZE - sizeof(struct pt_regs));
29}
30
31static void ptrace_single_step(struct task_struct *tsk)
32{
33 pr_debug("ptrace_single_step: pid=%u, SR=0x%08lx\n",
34 tsk->pid, tsk->thread.cpu_context.sr);
35 if (!(tsk->thread.cpu_context.sr & SR_D)) {
36 /*
37 * Set a breakpoint at the current pc to force the
38 * process into debug mode. The syscall/exception
39 * exit code will set a breakpoint at the return
40 * address when this flag is set.
41 */
42 pr_debug("ptrace_single_step: Setting TIF_BREAKPOINT\n");
43 set_tsk_thread_flag(tsk, TIF_BREAKPOINT);
44 }
45
46 /* The monitor code will do the actual step for us */
47 set_tsk_thread_flag(tsk, TIF_SINGLE_STEP);
48}
49
50/*
51 * Called by kernel/ptrace.c when detaching
52 *
53 * Make sure any single step bits, etc. are not set
54 */
55void ptrace_disable(struct task_struct *child)
56{
57 clear_tsk_thread_flag(child, TIF_SINGLE_STEP);
58}
59
60/*
61 * Handle hitting a breakpoint
62 */
63static void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
64{
65 siginfo_t info;
66
67 info.si_signo = SIGTRAP;
68 info.si_errno = 0;
69 info.si_code = TRAP_BRKPT;
70 info.si_addr = (void __user *)instruction_pointer(regs);
71
72 pr_debug("ptrace_break: Sending SIGTRAP to PID %u (pc = 0x%p)\n",
73 tsk->pid, info.si_addr);
74 force_sig_info(SIGTRAP, &info, tsk);
75}
76
77/*
78 * Read the word at offset "offset" into the task's "struct user". We
79 * actually access the pt_regs struct stored on the kernel stack.
80 */
81static int ptrace_read_user(struct task_struct *tsk, unsigned long offset,
82 unsigned long __user *data)
83{
84 unsigned long *regs;
85 unsigned long value;
86
87 pr_debug("ptrace_read_user(%p, %#lx, %p)\n",
88 tsk, offset, data);
89
90 if (offset & 3 || offset >= sizeof(struct user)) {
91 printk("ptrace_read_user: invalid offset 0x%08lx\n", offset);
92 return -EIO;
93 }
94
95 regs = (unsigned long *)get_user_regs(tsk);
96
97 value = 0;
98 if (offset < sizeof(struct pt_regs))
99 value = regs[offset / sizeof(regs[0])];
100
101 return put_user(value, data);
102}
103
104/*
105 * Write the word "value" to offset "offset" into the task's "struct
106 * user". We actually access the pt_regs struct stored on the kernel
107 * stack.
108 */
109static int ptrace_write_user(struct task_struct *tsk, unsigned long offset,
110 unsigned long value)
111{
112 unsigned long *regs;
113
114 if (offset & 3 || offset >= sizeof(struct user)) {
115 printk("ptrace_write_user: invalid offset 0x%08lx\n", offset);
116 return -EIO;
117 }
118
119 if (offset >= sizeof(struct pt_regs))
120 return 0;
121
122 regs = (unsigned long *)get_user_regs(tsk);
123 regs[offset / sizeof(regs[0])] = value;
124
125 return 0;
126}
127
128static int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
129{
130 struct pt_regs *regs = get_user_regs(tsk);
131
132 return copy_to_user(uregs, regs, sizeof(*regs)) ? -EFAULT : 0;
133}
134
135static int ptrace_setregs(struct task_struct *tsk, const void __user *uregs)
136{
137 struct pt_regs newregs;
138 int ret;
139
140 ret = -EFAULT;
141 if (copy_from_user(&newregs, uregs, sizeof(newregs)) == 0) {
142 struct pt_regs *regs = get_user_regs(tsk);
143
144 ret = -EINVAL;
145 if (valid_user_regs(&newregs)) {
146 *regs = newregs;
147 ret = 0;
148 }
149 }
150
151 return ret;
152}
153
154long arch_ptrace(struct task_struct *child, long request, long addr, long data)
155{
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -0700156 int ret;
157
Haavard Skinnemoen6ea850b2006-10-24 10:12:40 +0200158 pr_debug("arch_ptrace(%ld, %d, %#lx, %#lx)\n",
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -0700159 request, child->pid, addr, data);
160
161 pr_debug("ptrace: Enabling monitor mode...\n");
162 __mtdr(DBGREG_DC, __mfdr(DBGREG_DC) | DC_MM | DC_DBE);
163
164 switch (request) {
165 /* Read the word at location addr in the child process */
166 case PTRACE_PEEKTEXT:
167 case PTRACE_PEEKDATA:
Alexey Dobriyan76647322007-07-17 04:03:43 -0700168 ret = generic_ptrace_peekdata(child, addr, data);
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -0700169 break;
170
171 case PTRACE_PEEKUSR:
172 ret = ptrace_read_user(child, addr,
173 (unsigned long __user *)data);
174 break;
175
176 /* Write the word in data at location addr */
177 case PTRACE_POKETEXT:
178 case PTRACE_POKEDATA:
Alexey Dobriyanf284ce72007-07-17 04:03:44 -0700179 ret = generic_ptrace_pokedata(child, addr, data);
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -0700180 break;
181
182 case PTRACE_POKEUSR:
183 ret = ptrace_write_user(child, addr, data);
184 break;
185
186 /* continue and stop at next (return from) syscall */
187 case PTRACE_SYSCALL:
188 /* restart after signal */
189 case PTRACE_CONT:
190 ret = -EIO;
191 if (!valid_signal(data))
192 break;
193 if (request == PTRACE_SYSCALL)
194 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
195 else
196 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
197 child->exit_code = data;
198 /* XXX: Are we sure no breakpoints are active here? */
199 wake_up_process(child);
200 ret = 0;
201 break;
202
203 /*
204 * Make the child exit. Best I can do is send it a
205 * SIGKILL. Perhaps it should be put in the status that it
206 * wants to exit.
207 */
208 case PTRACE_KILL:
209 ret = 0;
210 if (child->exit_state == EXIT_ZOMBIE)
211 break;
212 child->exit_code = SIGKILL;
213 wake_up_process(child);
214 break;
215
216 /*
217 * execute single instruction.
218 */
219 case PTRACE_SINGLESTEP:
220 ret = -EIO;
221 if (!valid_signal(data))
222 break;
223 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
224 ptrace_single_step(child);
225 child->exit_code = data;
226 wake_up_process(child);
227 ret = 0;
228 break;
229
230 /* Detach a process that was attached */
231 case PTRACE_DETACH:
232 ret = ptrace_detach(child, data);
233 break;
234
235 case PTRACE_GETREGS:
236 ret = ptrace_getregs(child, (void __user *)data);
237 break;
238
239 case PTRACE_SETREGS:
240 ret = ptrace_setregs(child, (const void __user *)data);
241 break;
242
243 default:
244 ret = ptrace_request(child, request, addr, data);
245 break;
246 }
247
248 pr_debug("sys_ptrace returning %d (DC = 0x%08lx)\n", ret, __mfdr(DBGREG_DC));
249 return ret;
250}
251
252asmlinkage void syscall_trace(void)
253{
254 pr_debug("syscall_trace called\n");
255 if (!test_thread_flag(TIF_SYSCALL_TRACE))
256 return;
257 if (!(current->ptrace & PT_PTRACED))
258 return;
259
260 pr_debug("syscall_trace: notifying parent\n");
261 /* The 0x80 provides a way for the tracing parent to
262 * distinguish between a syscall stop and SIGTRAP delivery */
263 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
264 ? 0x80 : 0));
265
266 /*
267 * this isn't the same as continuing with a signal, but it
268 * will do for normal use. strace only continues with a
269 * signal if the stopping signal is not SIGTRAP. -brl
270 */
271 if (current->exit_code) {
272 pr_debug("syscall_trace: sending signal %d to PID %u\n",
273 current->exit_code, current->pid);
274 send_sig(current->exit_code, current, 1);
275 current->exit_code = 0;
276 }
277}
278
279asmlinkage void do_debug_priv(struct pt_regs *regs)
280{
281 unsigned long dc, ds;
282 unsigned long die_val;
283
284 ds = __mfdr(DBGREG_DS);
285
286 pr_debug("do_debug_priv: pc = %08lx, ds = %08lx\n", regs->pc, ds);
287
288 if (ds & DS_SSS)
289 die_val = DIE_SSTEP;
290 else
291 die_val = DIE_BREAKPOINT;
292
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700293 if (notify_die(die_val, "ptrace", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -0700294 return;
295
296 if (likely(ds & DS_SSS)) {
297 extern void itlb_miss(void);
298 extern void tlb_miss_common(void);
299 struct thread_info *ti;
300
301 dc = __mfdr(DBGREG_DC);
302 dc &= ~DC_SS;
303 __mtdr(DBGREG_DC, dc);
304
305 ti = current_thread_info();
Haavard Skinnemoena19b4a12007-03-01 10:37:35 +0100306 set_ti_thread_flag(ti, TIF_BREAKPOINT);
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -0700307
308 /* The TLB miss handlers don't check thread flags */
309 if ((regs->pc >= (unsigned long)&itlb_miss)
310 && (regs->pc <= (unsigned long)&tlb_miss_common)) {
311 __mtdr(DBGREG_BWA2A, sysreg_read(RAR_EX));
312 __mtdr(DBGREG_BWC2A, 0x40000001 | (get_asid() << 1));
313 }
314
315 /*
316 * If we're running in supervisor mode, the breakpoint
317 * will take us where we want directly, no need to
318 * single step.
319 */
320 if ((regs->sr & MODE_MASK) != MODE_SUPERVISOR)
Haavard Skinnemoena19b4a12007-03-01 10:37:35 +0100321 set_ti_thread_flag(ti, TIF_SINGLE_STEP);
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -0700322 } else {
323 panic("Unable to handle debug trap at pc = %08lx\n",
324 regs->pc);
325 }
326}
327
328/*
329 * Handle breakpoints, single steps and other debuggy things. To keep
330 * things simple initially, we run with interrupts and exceptions
331 * disabled all the time.
332 */
333asmlinkage void do_debug(struct pt_regs *regs)
334{
335 unsigned long dc, ds;
336
337 ds = __mfdr(DBGREG_DS);
338 pr_debug("do_debug: pc = %08lx, ds = %08lx\n", regs->pc, ds);
339
340 if (test_thread_flag(TIF_BREAKPOINT)) {
341 pr_debug("TIF_BREAKPOINT set\n");
342 /* We're taking care of it */
343 clear_thread_flag(TIF_BREAKPOINT);
344 __mtdr(DBGREG_BWC2A, 0);
345 }
346
347 if (test_thread_flag(TIF_SINGLE_STEP)) {
348 pr_debug("TIF_SINGLE_STEP set, ds = 0x%08lx\n", ds);
349 if (ds & DS_SSS) {
350 dc = __mfdr(DBGREG_DC);
351 dc &= ~DC_SS;
352 __mtdr(DBGREG_DC, dc);
353
354 clear_thread_flag(TIF_SINGLE_STEP);
355 ptrace_break(current, regs);
356 }
357 } else {
358 /* regular breakpoint */
359 ptrace_break(current, regs);
360 }
361}