x86/kernel/step.c

14 unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs)
38 		mutex_lock(&child->mm->context.lock);
39 		if (unlikely(!child->mm->context.ldt ||
40 			     seg >= child->mm->context.ldt->nr_entries))
43 			desc = &child->mm->context.ldt->entries[seg];
51 		mutex_unlock(&child->mm->context.lock);
58 static int is_setting_trap_flag(struct task_struct *child, struct pt_regs *regs)
62 	unsigned long addr = convert_ip_to_linear(child, regs);
64 	copied = access_process_vm(child, addr, opcode, sizeof(opcode),
113 static int enable_single_step(struct task_struct *child)
115 	struct pt_regs *regs = task_pt_regs(child);
128 	if (unlikely(test_tsk_thread_flag(child, TIF_SINGLESTEP)))
135 	set_tsk_thread_flag(child, TIF_SINGLESTEP);
141 	set_task_syscall_work(child, SYSCALL_EXIT_TRAP);
157 	if (is_setting_trap_flag(child, regs)) {
158 		clear_tsk_thread_flag(child, TIF_FORCED_TF);
167 		return test_tsk_thread_flag(child, TIF_FORCED_TF);
169 	set_tsk_thread_flag(child, TIF_FORCED_TF);
204 static void enable_step(struct task_struct *child, bool block)
213 	if (enable_single_step(child) && block)
214 		set_task_blockstep(child, true);
215 	else if (test_tsk_thread_flag(child, TIF_BLOCKSTEP))
216 		set_task_blockstep(child, false);
219 void user_enable_single_step(struct task_struct *child)
221 	enable_step(child, 0);
224 void user_enable_block_step(struct task_struct *child)
226 	enable_step(child, 1);
229 void user_disable_single_step(struct task_struct *child)
234 	if (test_tsk_thread_flag(child, TIF_BLOCKSTEP))
235 		set_task_blockstep(child, false);
238 	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
239 	clear_task_syscall_work(child, SYSCALL_EXIT_TRAP);
242 	if (test_and_clear_tsk_thread_flag(child, TIF_FORCED_TF))
243 		task_pt_regs(child)->flags &= ~X86_EFLAGS_TF;