1/*
  2 *  linux/arch/m68k/kernel/ptrace.c
  3 *
  4 *  Copyright (C) 1994 by Hamish Macdonald
  5 *  Taken from linux/kernel/ptrace.c and modified for M680x0.
  6 *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
  7 *
  8 * This file is subject to the terms and conditions of the GNU General
  9 * Public License.  See the file COPYING in the main directory of
 10 * this archive for more details.
 11 */
 12
 13#include <linux/kernel.h>
 14#include <linux/sched.h>
 15#include <linux/mm.h>
 16#include <linux/smp.h>
 17#include <linux/errno.h>
 18#include <linux/ptrace.h>
 19#include <linux/user.h>
 20#include <linux/signal.h>
 21
 22#include <asm/uaccess.h>
 23#include <asm/page.h>
 24#include <asm/pgtable.h>
 25#include <asm/system.h>
 26#include <asm/processor.h>
 27
 28/*
 29 * does not yet catch signals sent when the child dies.
 30 * in exit.c or in signal.c.
 31 */
 32
 33/* determines which bits in the SR the user has access to. */
 34/* 1 = access 0 = no access */
 35#define SR_MASK 0x001f
 36
 37/* sets the trace bits. */
 38#define TRACE_BITS 0xC000
 39#define T1_BIT 0x8000
 40#define T0_BIT 0x4000
 41
 42/* Find the stack offset for a register, relative to thread.esp0. */
 43#define PT_REG(reg)	((long)&((struct pt_regs *)0)->reg)
 44#define SW_REG(reg)	((long)&((struct switch_stack *)0)->reg \
 45			 - sizeof(struct switch_stack))
 46/* Mapping from PT_xxx to the stack offset at which the register is
 47   saved.  Notice that usp has no stack-slot and needs to be treated
 48   specially (see get_reg/put_reg below). */
 49static const int regoff[] = {
 50	[0]	= PT_REG(d1),
 51	[1]	= PT_REG(d2),
 52	[2]	= PT_REG(d3),
 53	[3]	= PT_REG(d4),
 54	[4]	= PT_REG(d5),
 55	[5]	= SW_REG(d6),
 56	[6]	= SW_REG(d7),
 57	[7]	= PT_REG(a0),
 58	[8]	= PT_REG(a1),
 59	[9]	= PT_REG(a2),
 60	[10]	= SW_REG(a3),
 61	[11]	= SW_REG(a4),
 62	[12]	= SW_REG(a5),
 63	[13]	= SW_REG(a6),
 64	[14]	= PT_REG(d0),
 65	[15]	= -1,
 66	[16]	= PT_REG(orig_d0),
 67	[17]	= PT_REG(sr),
 68	[18]	= PT_REG(pc),
 69};
 70
 71/*
 72 * Get contents of register REGNO in task TASK.
 73 */
 74static inline long get_reg(struct task_struct *task, int regno)
 75{
 76	unsigned long *addr;
 77
 78	if (regno == PT_USP)
 79		addr = &task->thread.usp;
 80	else if (regno < ARRAY_SIZE(regoff))
 81		addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
 82	else
 83		return 0;
 84	/* Need to take stkadj into account. */
 85	if (regno == PT_SR || regno == PT_PC) {
 86		long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj));
 87		addr = (unsigned long *) ((unsigned long)addr + stkadj);
 88		/* The sr is actually a 16 bit register.  */
 89		if (regno == PT_SR)
 90			return *(unsigned short *)addr;
 91	}
 92	return *addr;
 93}
 94
 95/*
 96 * Write contents of register REGNO in task TASK.
 97 */
 98static inline int put_reg(struct task_struct *task, int regno,
 99			  unsigned long data)
100{
101	unsigned long *addr;
102
103	if (regno == PT_USP)
104		addr = &task->thread.usp;
105	else if (regno < ARRAY_SIZE(regoff))
106		addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
107	else
108		return -1;
109	/* Need to take stkadj into account. */
110	if (regno == PT_SR || regno == PT_PC) {
111		long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj));
112		addr = (unsigned long *) ((unsigned long)addr + stkadj);
113		/* The sr is actually a 16 bit register.  */
114		if (regno == PT_SR) {
115			*(unsigned short *)addr = data;
116			return 0;
117		}
118	}
119	*addr = data;
120	return 0;
121}
122
123/*
124 * Make sure the single step bit is not set.
125 */
126static inline void singlestep_disable(struct task_struct *child)
127{
128	unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
129	put_reg(child, PT_SR, tmp);
130	clear_tsk_thread_flag(child, TIF_DELAYED_TRACE);
131}
132
133/*
134 * Called by kernel/ptrace.c when detaching..
135 */
136void ptrace_disable(struct task_struct *child)
137{
138	singlestep_disable(child);
139}
140
141void user_enable_single_step(struct task_struct *child)
142{
143	unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
144	put_reg(child, PT_SR, tmp | T1_BIT);
145	set_tsk_thread_flag(child, TIF_DELAYED_TRACE);
146}
147
148void user_enable_block_step(struct task_struct *child)
149{
150	unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
151	put_reg(child, PT_SR, tmp | T0_BIT);
152}
153
154void user_disable_single_step(struct task_struct *child)
155{
156	singlestep_disable(child);
157}
158
159long arch_ptrace(struct task_struct *child, long request,
160		 unsigned long addr, unsigned long data)
161{
162	unsigned long tmp;
163	int i, ret = 0;
164	int regno = addr >> 2; /* temporary hack. */
165	unsigned long __user *datap = (unsigned long __user *) data;
166
167	switch (request) {
168	/* read the word at location addr in the USER area. */
169	case PTRACE_PEEKUSR:
170		if (addr & 3)
171			goto out_eio;
172
173		if (regno >= 0 && regno < 19) {
174			tmp = get_reg(child, regno);
175		} else if (regno >= 21 && regno < 49) {
176			tmp = child->thread.fp[regno - 21];
177			/* Convert internal fpu reg representation
178			 * into long double format
179			 */
180			if (FPU_IS_EMU && (regno < 45) && !(regno % 3))
181				tmp = ((tmp & 0xffff0000) << 15) |
182				      ((tmp & 0x0000ffff) << 16);
183		} else
184			goto out_eio;
185		ret = put_user(tmp, datap);
186		break;
187
188	case PTRACE_POKEUSR:
189	/* write the word at location addr in the USER area */
190		if (addr & 3)
191			goto out_eio;
192
193		if (regno == PT_SR) {
194			data &= SR_MASK;
195			data |= get_reg(child, PT_SR) & ~SR_MASK;
196		}
197		if (regno >= 0 && regno < 19) {
198			if (put_reg(child, regno, data))
199				goto out_eio;
200		} else if (regno >= 21 && regno < 48) {
201			/* Convert long double format
202			 * into internal fpu reg representation
203			 */
204			if (FPU_IS_EMU && (regno < 45) && !(regno % 3)) {
205				data <<= 15;
206				data = (data & 0xffff0000) |
207				       ((data & 0x0000ffff) >> 1);
208			}
209			child->thread.fp[regno - 21] = data;
210		} else
211			goto out_eio;
212		break;
213
214	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
215		for (i = 0; i < 19; i++) {
216			tmp = get_reg(child, i);
217			ret = put_user(tmp, datap);
218			if (ret)
219				break;
220			datap++;
221		}
222		break;
223
224	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
225		for (i = 0; i < 19; i++) {
226			ret = get_user(tmp, datap);
227			if (ret)
228				break;
229			if (i == PT_SR) {
230				tmp &= SR_MASK;
231				tmp |= get_reg(child, PT_SR) & ~SR_MASK;
232			}
233			put_reg(child, i, tmp);
234			datap++;
235		}
236		break;
237
238	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
239		if (copy_to_user(datap, &child->thread.fp,
240				 sizeof(struct user_m68kfp_struct)))
241			ret = -EFAULT;
242		break;
243
244	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
245		if (copy_from_user(&child->thread.fp, datap,
246				   sizeof(struct user_m68kfp_struct)))
247			ret = -EFAULT;
248		break;
249
250	case PTRACE_GET_THREAD_AREA:
251		ret = put_user(task_thread_info(child)->tp_value, datap);
252		break;
253
254	default:
255		ret = ptrace_request(child, request, addr, data);
256		break;
257	}
258
259	return ret;
260out_eio:
261	return -EIO;
262}
263
264asmlinkage void syscall_trace(void)
265{
266	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
267				 ? 0x80 : 0));
268	/*
269	 * this isn't the same as continuing with a signal, but it will do
270	 * for normal use.  strace only continues with a signal if the
271	 * stopping signal is not SIGTRAP.  -brl
272	 */
273	if (current->exit_code) {
274		send_sig(current->exit_code, current, 1);
275		current->exit_code = 0;
276	}
277}