2 * Copyright (C) 2000-2003, Axis Communications AB.
5 #include <linux/kernel.h>
6 #include <linux/sched.h>
9 #include <linux/smp_lock.h>
10 #include <linux/errno.h>
11 #include <linux/ptrace.h>
12 #include <linux/user.h>
14 #include <asm/uaccess.h>
16 #include <asm/pgtable.h>
17 #include <asm/system.h>
18 #include <asm/processor.h>
21 * Determines which bits in DCCR the user has access to.
22 * 1 = access, 0 = no access.
24 #define DCCR_MASK 0x0000001f /* XNZVC */
27 * Get contents of register REGNO in task TASK.
29 inline long get_reg(struct task_struct *task, unsigned int regno)
31 /* USP is a special case, it's not in the pt_regs struct but
32 * in the tasks thread struct
36 return task->thread.usp;
37 else if (regno < PT_MAX)
38 return ((unsigned long *)user_regs(task->thread_info))[regno];
44 * Write contents of register REGNO in task TASK.
46 inline int put_reg(struct task_struct *task, unsigned int regno,
50 task->thread.usp = data;
51 else if (regno < PT_MAX)
52 ((unsigned long *)user_regs(task->thread_info))[regno] = data;
59 * Called by kernel/ptrace.c when detaching.
61 * Make sure the single step bit is not set.
64 ptrace_disable(struct task_struct *child)
66 /* Todo - pending singlesteps? */
70 * Note that this implementation of ptrace behaves differently from vanilla
71 * ptrace. Contrary to what the man page says, in the PTRACE_PEEKTEXT,
72 * PTRACE_PEEKDATA, and PTRACE_PEEKUSER requests the data variable is not
73 * ignored. Instead, the data variable is expected to point at a location
74 * (in user space) where the result of the ptrace call is written (instead of
78 sys_ptrace(long request, long pid, long addr, long data)
80 struct task_struct *child;
82 unsigned long __user *datap = (unsigned long __user *)data;
87 if (request == PTRACE_TRACEME) {
88 if (current->ptrace & PT_PTRACED)
91 current->ptrace |= PT_PTRACED;
97 read_lock(&tasklist_lock);
98 child = find_task_by_pid(pid);
101 get_task_struct(child);
103 read_unlock(&tasklist_lock);
110 if (pid == 1) /* Leave the init process alone! */
113 if (request == PTRACE_ATTACH) {
114 ret = ptrace_attach(child);
118 ret = ptrace_check_attach(child, request == PTRACE_KILL);
123 /* Read word at location address. */
124 case PTRACE_PEEKTEXT:
125 case PTRACE_PEEKDATA: {
129 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
132 if (copied != sizeof(tmp))
135 ret = put_user(tmp,datap);
139 /* Read the word at location address in the USER area. */
140 case PTRACE_PEEKUSR: {
144 if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
147 tmp = get_reg(child, addr >> 2);
148 ret = put_user(tmp, datap);
152 /* Write the word at location address. */
153 case PTRACE_POKETEXT:
154 case PTRACE_POKEDATA:
157 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
163 /* Write the word at location address in the USER area. */
166 if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
171 if (addr == PT_DCCR) {
172 /* don't allow the tracing process to change stuff like
173 * interrupt enable, kernel/user bit, dma enables etc.
176 data |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
178 if (put_reg(child, addr, data))
187 if ((unsigned long) data > _NSIG)
190 if (request == PTRACE_SYSCALL) {
191 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
194 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
197 child->exit_code = data;
199 /* TODO: make sure any pending breakpoint is killed */
200 wake_up_process(child);
205 /* Make the child exit by sending it a sigkill. */
209 if (child->state == TASK_ZOMBIE)
212 child->exit_code = SIGKILL;
214 /* TODO: make sure any pending breakpoint is killed */
215 wake_up_process(child);
218 /* Set the trap flag. */
219 case PTRACE_SINGLESTEP:
222 if ((unsigned long) data > _NSIG)
225 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
227 /* TODO: set some clever breakpoint mechanism... */
229 child->exit_code = data;
230 wake_up_process(child);
235 ret = ptrace_detach(child, data);
238 /* Get all GP registers from the child. */
239 case PTRACE_GETREGS: {
243 for (i = 0; i <= PT_MAX; i++) {
244 tmp = get_reg(child, i);
246 if (put_user(tmp, datap)) {
251 data += sizeof(long);
258 /* Set all GP registers in the child. */
259 case PTRACE_SETREGS: {
263 for (i = 0; i <= PT_MAX; i++) {
264 if (get_user(tmp, datap)) {
271 tmp |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
274 put_reg(child, i, tmp);
275 data += sizeof(long);
283 ret = ptrace_request(child, request, addr, data);
287 put_task_struct(child);
293 void do_syscall_trace(void)
295 if (!test_thread_flag(TIF_SYSCALL_TRACE))
298 if (!(current->ptrace & PT_PTRACED))
301 /* the 0x80 provides a way for the tracing parent to distinguish
302 between a syscall stop and SIGTRAP delivery */
303 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
307 * This isn't the same as continuing with a signal, but it will do for
310 if (current->exit_code) {
311 send_sig(current->exit_code, current, 1);
312 current->exit_code = 0;