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 */
26 extern inline long get_reg(struct task_struct *, unsigned int);
27 extern inline long put_reg(struct task_struct *, unsigned int, unsigned long);
30 * Called by kernel/ptrace.c when detaching.
32 * Make sure the single step bit is not set.
35 ptrace_disable(struct task_struct *child)
37 /* Todo - pending singlesteps? */
41 * Note that this implementation of ptrace behaves differently from vanilla
42 * ptrace. Contrary to what the man page says, in the PTRACE_PEEKTEXT,
43 * PTRACE_PEEKDATA, and PTRACE_PEEKUSER requests the data variable is not
44 * ignored. Instead, the data variable is expected to point at a location
45 * (in user space) where the result of the ptrace call is written (instead of
49 sys_ptrace(long request, long pid, long addr, long data)
51 struct task_struct *child;
57 if (request == PTRACE_TRACEME) {
58 if (current->ptrace & PT_PTRACED)
61 current->ptrace |= PT_PTRACED;
67 read_lock(&tasklist_lock);
68 child = find_task_by_pid(pid);
71 get_task_struct(child);
73 read_unlock(&tasklist_lock);
80 if (pid == 1) /* Leave the init process alone! */
83 if (request == PTRACE_ATTACH) {
84 ret = ptrace_attach(child);
90 if (!(child->ptrace & PT_PTRACED))
93 if (child->state != TASK_STOPPED) {
94 if (request != PTRACE_KILL)
98 if (child->parent != current)
102 /* Read word at location address. */
103 case PTRACE_PEEKTEXT:
104 case PTRACE_PEEKDATA: {
108 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
111 if (copied != sizeof(tmp))
114 ret = put_user(tmp,(unsigned long *) data);
118 /* Read the word at location address in the USER area. */
119 case PTRACE_PEEKUSR: {
123 if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
126 tmp = get_reg(child, addr >> 2);
127 ret = put_user(tmp, (unsigned long *)data);
131 /* Write the word at location address. */
132 case PTRACE_POKETEXT:
133 case PTRACE_POKEDATA:
136 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
142 /* Write the word at location address in the USER area. */
145 if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
150 if (addr == PT_DCCR) {
151 /* don't allow the tracing process to change stuff like
152 * interrupt enable, kernel/user bit, dma enables etc.
155 data |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
157 if (put_reg(child, addr, data))
166 if ((unsigned long) data > _NSIG)
169 if (request == PTRACE_SYSCALL) {
170 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
173 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
176 child->exit_code = data;
178 /* TODO: make sure any pending breakpoint is killed */
179 wake_up_process(child);
184 /* Make the child exit by sending it a sigkill. */
188 if (child->state == TASK_ZOMBIE)
191 child->exit_code = SIGKILL;
193 /* TODO: make sure any pending breakpoint is killed */
194 wake_up_process(child);
197 /* Set the trap flag. */
198 case PTRACE_SINGLESTEP:
201 if ((unsigned long) data > _NSIG)
204 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
206 /* TODO: set some clever breakpoint mechanism... */
208 child->exit_code = data;
209 wake_up_process(child);
214 ret = ptrace_detach(child, data);
217 /* Get all GP registers from the child. */
218 case PTRACE_GETREGS: {
222 for (i = 0; i <= PT_MAX; i++) {
223 tmp = get_reg(child, i);
225 if (put_user(tmp, (unsigned long *) data)) {
230 data += sizeof(long);
237 /* Set all GP registers in the child. */
238 case PTRACE_SETREGS: {
242 for (i = 0; i <= PT_MAX; i++) {
243 if (get_user(tmp, (unsigned long *) data)) {
250 tmp |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
253 put_reg(child, i, tmp);
254 data += sizeof(long);
262 ret = ptrace_request(child, request, addr, data);
266 put_task_struct(child);
272 void do_syscall_trace(void)
274 if (!test_thread_flag(TIF_SYSCALL_TRACE))
277 if (!(current->ptrace & PT_PTRACED))
280 /* the 0x80 provides a way for the tracing parent to distinguish
281 between a syscall stop and SIGTRAP delivery */
282 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
286 * This isn't the same as continuing with a signal, but it will do for
289 if (current->exit_code) {
290 send_sig(current->exit_code, current, 1);
291 current->exit_code = 0;