1/*
  2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
  3 *
  4 *   This program is free software; you can redistribute it and/or
  5 *   modify it under the terms of the GNU General Public License
  6 *   as published by the Free Software Foundation, version 2.
  7 *
  8 *   This program is distributed in the hope that it will be useful, but
  9 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 10 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 11 *   NON INFRINGEMENT.  See the GNU General Public License for
 12 *   more details.
 13 *
 14 * Copied from i386: Ross Biro 1/23/92
 15 */
 16
 17#include <linux/kernel.h>
 18#include <linux/ptrace.h>
 19#include <linux/kprobes.h>
 20#include <linux/compat.h>
 21#include <linux/uaccess.h>
 22#include <asm/traps.h>
 23
 24void user_enable_single_step(struct task_struct *child)
 25{
 26	set_tsk_thread_flag(child, TIF_SINGLESTEP);
 27}
 28
 29void user_disable_single_step(struct task_struct *child)
 30{
 31	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
 32}
 33
 34/*
 35 * Called by kernel/ptrace.c when detaching..
 36 */
 37void ptrace_disable(struct task_struct *child)
 38{
 39	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
 40
 41	/*
 42	 * These two are currently unused, but will be set by arch_ptrace()
 43	 * and used in the syscall assembly when we do support them.
 44	 */
 45	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 46}
 47
 48long arch_ptrace(struct task_struct *child, long request,
 49		 unsigned long addr, unsigned long data)
 50{
 51	unsigned long __user *datap = (long __user __force *)data;
 52	unsigned long tmp;
 53	long ret = -EIO;
 54	char *childreg;
 55	struct pt_regs copyregs;
 56	int ex1_offset;
 57
 58	switch (request) {
 59
 60	case PTRACE_PEEKUSR:  /* Read register from pt_regs. */
 61		if (addr >= PTREGS_SIZE)
 62			break;
 63		childreg = (char *)task_pt_regs(child) + addr;
 64#ifdef CONFIG_COMPAT
 65		if (is_compat_task()) {
 66			if (addr & (sizeof(compat_long_t)-1))
 67				break;
 68			ret = put_user(*(compat_long_t *)childreg,
 69				       (compat_long_t __user *)datap);
 70		} else
 71#endif
 72		{
 73			if (addr & (sizeof(long)-1))
 74				break;
 75			ret = put_user(*(long *)childreg, datap);
 76		}
 77		break;
 78
 79	case PTRACE_POKEUSR:  /* Write register in pt_regs. */
 80		if (addr >= PTREGS_SIZE)
 81			break;
 82		childreg = (char *)task_pt_regs(child) + addr;
 83
 84		/* Guard against overwrites of the privilege level. */
 85		ex1_offset = PTREGS_OFFSET_EX1;
 86#if defined(CONFIG_COMPAT) && defined(__BIG_ENDIAN)
 87		if (is_compat_task())   /* point at low word */
 88			ex1_offset += sizeof(compat_long_t);
 89#endif
 90		if (addr == ex1_offset)
 91			data = PL_ICS_EX1(USER_PL, EX1_ICS(data));
 92
 93#ifdef CONFIG_COMPAT
 94		if (is_compat_task()) {
 95			if (addr & (sizeof(compat_long_t)-1))
 96				break;
 97			*(compat_long_t *)childreg = data;
 98		} else
 99#endif
100		{
101			if (addr & (sizeof(long)-1))
102				break;
103			*(long *)childreg = data;
104		}
105		ret = 0;
106		break;
107
108	case PTRACE_GETREGS:  /* Get all registers from the child. */
109		if (copy_to_user(datap, task_pt_regs(child),
110				 sizeof(struct pt_regs)) == 0) {
111			ret = 0;
112		}
113		break;
114
115	case PTRACE_SETREGS:  /* Set all registers in the child. */
116		if (copy_from_user(&copyregs, datap,
117				   sizeof(struct pt_regs)) == 0) {
118			copyregs.ex1 =
119				PL_ICS_EX1(USER_PL, EX1_ICS(copyregs.ex1));
120			*task_pt_regs(child) = copyregs;
121			ret = 0;
122		}
123		break;
124
125	case PTRACE_GETFPREGS:  /* Get the child FPU state. */
126	case PTRACE_SETFPREGS:  /* Set the child FPU state. */
127		break;
128
129	case PTRACE_SETOPTIONS:
130		/* Support TILE-specific ptrace options. */
131		child->ptrace &= ~PT_TRACE_MASK_TILE;
132		tmp = data & PTRACE_O_MASK_TILE;
133		data &= ~PTRACE_O_MASK_TILE;
134		ret = ptrace_request(child, request, addr, data);
135		if (tmp & PTRACE_O_TRACEMIGRATE)
136			child->ptrace |= PT_TRACE_MIGRATE;
137		break;
138
139	default:
140#ifdef CONFIG_COMPAT
141		if (task_thread_info(current)->status & TS_COMPAT) {
142			ret = compat_ptrace_request(child, request,
143						    addr, data);
144			break;
145		}
146#endif
147		ret = ptrace_request(child, request, addr, data);
148		break;
149	}
150
151	return ret;
152}
153
154#ifdef CONFIG_COMPAT
155/* Not used; we handle compat issues in arch_ptrace() directly. */
156long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
157			       compat_ulong_t addr, compat_ulong_t data)
158{
159	BUG();
160}
161#endif
162
163void do_syscall_trace(void)
164{
165	if (!test_thread_flag(TIF_SYSCALL_TRACE))
166		return;
167
168	if (!(current->ptrace & PT_PTRACED))
169		return;
170
171	/*
172	 * The 0x80 provides a way for the tracing parent to distinguish
173	 * between a syscall stop and SIGTRAP delivery
174	 */
175	ptrace_notify(SIGTRAP|((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
176
177	/*
178	 * this isn't the same as continuing with a signal, but it will do
179	 * for normal use.  strace only continues with a signal if the
180	 * stopping signal is not SIGTRAP.  -brl
181	 */
182	if (current->exit_code) {
183		send_sig(current->exit_code, current, 1);
184		current->exit_code = 0;
185	}
186}
187
188void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)
189{
190	struct siginfo info;
191
192	memset(&info, 0, sizeof(info));
193	info.si_signo = SIGTRAP;
194	info.si_code  = TRAP_BRKPT;
195	info.si_addr  = (void __user *) regs->pc;
196
197	/* Send us the fakey SIGTRAP */
198	force_sig_info(SIGTRAP, &info, tsk);
199}
200
201/* Handle synthetic interrupt delivered only by the simulator. */
202void __kprobes do_breakpoint(struct pt_regs* regs, int fault_num)
203{
204	send_sigtrap(current, regs, fault_num);
205}