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). */
49 static 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 */
get_reg(struct task_struct * task,int regno)74 static 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 */
put_reg(struct task_struct * task,int regno,unsigned long data)98 static 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 */
singlestep_disable(struct task_struct * child)126 static 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 */
ptrace_disable(struct task_struct * child)136 void ptrace_disable(struct task_struct *child)
137 {
138 singlestep_disable(child);
139 }
140
user_enable_single_step(struct task_struct * child)141 void 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
user_enable_block_step(struct task_struct * child)148 void 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
user_disable_single_step(struct task_struct * child)154 void user_disable_single_step(struct task_struct *child)
155 {
156 singlestep_disable(child);
157 }
158
arch_ptrace(struct task_struct * child,long request,unsigned long addr,unsigned long data)159 long 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;
260 out_eio:
261 return -EIO;
262 }
263
syscall_trace(void)264 asmlinkage 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 }
278