2 * Copyright (C) 2004-2006 Atmel Corporation
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.
9 #include <linux/kernel.h>
10 #include <linux/sched.h>
12 #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>
19 #include <asm/traps.h>
20 #include <asm/uaccess.h>
22 #include <asm/mmu_context.h>
23 #include <linux/kdebug.h>
25 static struct pt_regs *get_user_regs(struct task_struct *tsk)
27 return (struct pt_regs *)((unsigned long)task_stack_page(tsk) +
28 THREAD_SIZE - sizeof(struct pt_regs));
31 static void ptrace_single_step(struct task_struct *tsk)
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)) {
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.
42 pr_debug("ptrace_single_step: Setting TIF_BREAKPOINT\n");
43 set_tsk_thread_flag(tsk, TIF_BREAKPOINT);
46 /* The monitor code will do the actual step for us */
47 set_tsk_thread_flag(tsk, TIF_SINGLE_STEP);
51 * Called by kernel/ptrace.c when detaching
53 * Make sure any single step bits, etc. are not set
55 void ptrace_disable(struct task_struct *child)
57 clear_tsk_thread_flag(child, TIF_SINGLE_STEP);
61 * Handle hitting a breakpoint
63 static void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
67 info.si_signo = SIGTRAP;
69 info.si_code = TRAP_BRKPT;
70 info.si_addr = (void __user *)instruction_pointer(regs);
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);
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.
81 static int ptrace_read_user(struct task_struct *tsk, unsigned long offset,
82 unsigned long __user *data)
87 pr_debug("ptrace_read_user(%p, %#lx, %p)\n",
90 if (offset & 3 || offset >= sizeof(struct user)) {
91 printk("ptrace_read_user: invalid offset 0x%08lx\n", offset);
95 regs = (unsigned long *)get_user_regs(tsk);
98 if (offset < sizeof(struct pt_regs))
99 value = regs[offset / sizeof(regs[0])];
101 return put_user(value, data);
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
109 static int ptrace_write_user(struct task_struct *tsk, unsigned long offset,
114 if (offset & 3 || offset >= sizeof(struct user)) {
115 printk("ptrace_write_user: invalid offset 0x%08lx\n", offset);
119 if (offset >= sizeof(struct pt_regs))
122 regs = (unsigned long *)get_user_regs(tsk);
123 regs[offset / sizeof(regs[0])] = value;
128 static int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
130 struct pt_regs *regs = get_user_regs(tsk);
132 return copy_to_user(uregs, regs, sizeof(*regs)) ? -EFAULT : 0;
135 static int ptrace_setregs(struct task_struct *tsk, const void __user *uregs)
137 struct pt_regs newregs;
141 if (copy_from_user(&newregs, uregs, sizeof(newregs)) == 0) {
142 struct pt_regs *regs = get_user_regs(tsk);
145 if (valid_user_regs(&newregs)) {
154 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
158 pr_debug("arch_ptrace(%ld, %d, %#lx, %#lx)\n",
159 request, child->pid, addr, data);
161 pr_debug("ptrace: Enabling monitor mode...\n");
162 __mtdr(DBGREG_DC, __mfdr(DBGREG_DC) | DC_MM | DC_DBE);
165 /* Read the word at location addr in the child process */
166 case PTRACE_PEEKTEXT:
167 case PTRACE_PEEKDATA:
168 ret = generic_ptrace_peekdata(child, addr, data);
172 ret = ptrace_read_user(child, addr,
173 (unsigned long __user *)data);
176 /* Write the word in data at location addr */
177 case PTRACE_POKETEXT:
178 case PTRACE_POKEDATA:
179 ret = generic_ptrace_pokedata(child, addr, data);
183 ret = ptrace_write_user(child, addr, data);
186 /* continue and stop at next (return from) syscall */
188 /* restart after signal */
191 if (!valid_signal(data))
193 if (request == PTRACE_SYSCALL)
194 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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);
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
210 if (child->exit_state == EXIT_ZOMBIE)
212 child->exit_code = SIGKILL;
213 wake_up_process(child);
217 * execute single instruction.
219 case PTRACE_SINGLESTEP:
221 if (!valid_signal(data))
223 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
224 ptrace_single_step(child);
225 child->exit_code = data;
226 wake_up_process(child);
231 ret = ptrace_getregs(child, (void __user *)data);
235 ret = ptrace_setregs(child, (const void __user *)data);
239 ret = ptrace_request(child, request, addr, data);
243 pr_debug("sys_ptrace returning %d (DC = 0x%08lx)\n", ret, __mfdr(DBGREG_DC));
247 asmlinkage void syscall_trace(void)
249 pr_debug("syscall_trace called\n");
250 if (!test_thread_flag(TIF_SYSCALL_TRACE))
252 if (!(current->ptrace & PT_PTRACED))
255 pr_debug("syscall_trace: notifying parent\n");
256 /* The 0x80 provides a way for the tracing parent to
257 * distinguish between a syscall stop and SIGTRAP delivery */
258 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
262 * this isn't the same as continuing with a signal, but it
263 * will do for normal use. strace only continues with a
264 * signal if the stopping signal is not SIGTRAP. -brl
266 if (current->exit_code) {
267 pr_debug("syscall_trace: sending signal %d to PID %u\n",
268 current->exit_code, current->pid);
269 send_sig(current->exit_code, current, 1);
270 current->exit_code = 0;
274 asmlinkage void do_debug_priv(struct pt_regs *regs)
276 unsigned long dc, ds;
277 unsigned long die_val;
279 ds = __mfdr(DBGREG_DS);
281 pr_debug("do_debug_priv: pc = %08lx, ds = %08lx\n", regs->pc, ds);
286 die_val = DIE_BREAKPOINT;
288 if (notify_die(die_val, "ptrace", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
291 if (likely(ds & DS_SSS)) {
292 extern void itlb_miss(void);
293 extern void tlb_miss_common(void);
294 struct thread_info *ti;
296 dc = __mfdr(DBGREG_DC);
298 __mtdr(DBGREG_DC, dc);
300 ti = current_thread_info();
301 set_ti_thread_flag(ti, TIF_BREAKPOINT);
303 /* The TLB miss handlers don't check thread flags */
304 if ((regs->pc >= (unsigned long)&itlb_miss)
305 && (regs->pc <= (unsigned long)&tlb_miss_common)) {
306 __mtdr(DBGREG_BWA2A, sysreg_read(RAR_EX));
307 __mtdr(DBGREG_BWC2A, 0x40000001 | (get_asid() << 1));
311 * If we're running in supervisor mode, the breakpoint
312 * will take us where we want directly, no need to
315 if ((regs->sr & MODE_MASK) != MODE_SUPERVISOR)
316 set_ti_thread_flag(ti, TIF_SINGLE_STEP);
318 panic("Unable to handle debug trap at pc = %08lx\n",
324 * Handle breakpoints, single steps and other debuggy things. To keep
325 * things simple initially, we run with interrupts and exceptions
326 * disabled all the time.
328 asmlinkage void do_debug(struct pt_regs *regs)
330 unsigned long dc, ds;
332 ds = __mfdr(DBGREG_DS);
333 pr_debug("do_debug: pc = %08lx, ds = %08lx\n", regs->pc, ds);
335 if (test_thread_flag(TIF_BREAKPOINT)) {
336 pr_debug("TIF_BREAKPOINT set\n");
337 /* We're taking care of it */
338 clear_thread_flag(TIF_BREAKPOINT);
339 __mtdr(DBGREG_BWC2A, 0);
342 if (test_thread_flag(TIF_SINGLE_STEP)) {
343 pr_debug("TIF_SINGLE_STEP set, ds = 0x%08lx\n", ds);
345 dc = __mfdr(DBGREG_DC);
347 __mtdr(DBGREG_DC, dc);
349 clear_thread_flag(TIF_SINGLE_STEP);
350 ptrace_break(current, regs);
353 /* regular breakpoint */
354 ptrace_break(current, regs);