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/sched/task_stack.h>
16 #include <linux/mm.h>
17 #include <linux/smp.h>
18 #include <linux/errno.h>
19 #include <linux/ptrace.h>
20 #include <linux/user.h>
21 #include <linux/signal.h>
22 #include <linux/regset.h>
23 #include <linux/elf.h>
24 #include <linux/seccomp.h>
25 #include <linux/uaccess.h>
26 #include <asm/page.h>
27 #include <asm/processor.h>
28
29 #include "ptrace.h"
30
31 /*
32 * does not yet catch signals sent when the child dies.
33 * in exit.c or in signal.c.
34 */
35
36 /* determines which bits in the SR the user has access to. */
37 /* 1 = access 0 = no access */
38 #define SR_MASK 0x001f
39
40 /* sets the trace bits. */
41 #define TRACE_BITS 0xC000
42 #define T1_BIT 0x8000
43 #define T0_BIT 0x4000
44
45 /* Find the stack offset for a register, relative to thread.esp0. */
46 #define PT_REG(reg) ((long)&((struct pt_regs *)0)->reg)
47 #define SW_REG(reg) ((long)&((struct switch_stack *)0)->reg \
48 - sizeof(struct switch_stack))
49 /* Mapping from PT_xxx to the stack offset at which the register is
50 saved. Notice that usp has no stack-slot and needs to be treated
51 specially (see get_reg/put_reg below). */
52 static const int regoff[] = {
53 [0] = PT_REG(d1),
54 [1] = PT_REG(d2),
55 [2] = PT_REG(d3),
56 [3] = PT_REG(d4),
57 [4] = PT_REG(d5),
58 [5] = SW_REG(d6),
59 [6] = SW_REG(d7),
60 [7] = PT_REG(a0),
61 [8] = PT_REG(a1),
62 [9] = PT_REG(a2),
63 [10] = SW_REG(a3),
64 [11] = SW_REG(a4),
65 [12] = SW_REG(a5),
66 [13] = SW_REG(a6),
67 [14] = PT_REG(d0),
68 [15] = -1,
69 [16] = PT_REG(orig_d0),
70 [17] = PT_REG(sr),
71 [18] = PT_REG(pc),
72 };
73
74 /*
75 * Get contents of register REGNO in task TASK.
76 */
get_reg(struct task_struct * task,int regno)77 static inline long get_reg(struct task_struct *task, int regno)
78 {
79 unsigned long *addr;
80
81 if (regno == PT_USP)
82 addr = &task->thread.usp;
83 else if (regno < ARRAY_SIZE(regoff))
84 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
85 else
86 return 0;
87 /* Need to take stkadj into account. */
88 if (regno == PT_SR || regno == PT_PC) {
89 long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj));
90 addr = (unsigned long *) ((unsigned long)addr + stkadj);
91 /* The sr is actually a 16 bit register. */
92 if (regno == PT_SR)
93 return *(unsigned short *)addr;
94 }
95 return *addr;
96 }
97
98 /*
99 * Write contents of register REGNO in task TASK.
100 */
put_reg(struct task_struct * task,int regno,unsigned long data)101 static inline int put_reg(struct task_struct *task, int regno,
102 unsigned long data)
103 {
104 unsigned long *addr;
105
106 if (regno == PT_USP)
107 addr = &task->thread.usp;
108 else if (regno < ARRAY_SIZE(regoff))
109 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
110 else
111 return -1;
112 /* Need to take stkadj into account. */
113 if (regno == PT_SR || regno == PT_PC) {
114 long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj));
115 addr = (unsigned long *) ((unsigned long)addr + stkadj);
116 /* The sr is actually a 16 bit register. */
117 if (regno == PT_SR) {
118 *(unsigned short *)addr = data;
119 return 0;
120 }
121 }
122 *addr = data;
123 return 0;
124 }
125
126 /*
127 * Make sure the single step bit is not set.
128 */
singlestep_disable(struct task_struct * child)129 static inline void singlestep_disable(struct task_struct *child)
130 {
131 unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
132 put_reg(child, PT_SR, tmp);
133 clear_tsk_thread_flag(child, TIF_DELAYED_TRACE);
134 }
135
136 /*
137 * Called by kernel/ptrace.c when detaching..
138 */
ptrace_disable(struct task_struct * child)139 void ptrace_disable(struct task_struct *child)
140 {
141 singlestep_disable(child);
142 }
143
user_enable_single_step(struct task_struct * child)144 void user_enable_single_step(struct task_struct *child)
145 {
146 unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
147 put_reg(child, PT_SR, tmp | T1_BIT);
148 set_tsk_thread_flag(child, TIF_DELAYED_TRACE);
149 }
150
151 #ifdef CONFIG_MMU
user_enable_block_step(struct task_struct * child)152 void user_enable_block_step(struct task_struct *child)
153 {
154 unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
155 put_reg(child, PT_SR, tmp | T0_BIT);
156 }
157 #endif
158
user_disable_single_step(struct task_struct * child)159 void user_disable_single_step(struct task_struct *child)
160 {
161 singlestep_disable(child);
162 }
163
arch_ptrace(struct task_struct * child,long request,unsigned long addr,unsigned long data)164 long arch_ptrace(struct task_struct *child, long request,
165 unsigned long addr, unsigned long data)
166 {
167 unsigned long tmp;
168 int i, ret = 0;
169 int regno = addr >> 2; /* temporary hack. */
170 unsigned long __user *datap = (unsigned long __user *) data;
171
172 switch (request) {
173 /* read the word at location addr in the USER area. */
174 case PTRACE_PEEKUSR:
175 if (addr & 3)
176 goto out_eio;
177
178 if (regno >= 0 && regno < 19) {
179 tmp = get_reg(child, regno);
180 } else if (regno >= 21 && regno < 49) {
181 tmp = child->thread.fp[regno - 21];
182 /* Convert internal fpu reg representation
183 * into long double format
184 */
185 if (FPU_IS_EMU && (regno < 45) && !(regno % 3))
186 tmp = ((tmp & 0xffff0000) << 15) |
187 ((tmp & 0x0000ffff) << 16);
188 #ifndef CONFIG_MMU
189 } else if (regno == 49) {
190 tmp = child->mm->start_code;
191 } else if (regno == 50) {
192 tmp = child->mm->start_data;
193 } else if (regno == 51) {
194 tmp = child->mm->end_code;
195 #endif
196 } else
197 goto out_eio;
198 ret = put_user(tmp, datap);
199 break;
200
201 case PTRACE_POKEUSR:
202 /* write the word at location addr in the USER area */
203 if (addr & 3)
204 goto out_eio;
205
206 if (regno == PT_SR) {
207 data &= SR_MASK;
208 data |= get_reg(child, PT_SR) & ~SR_MASK;
209 }
210 if (regno >= 0 && regno < 19) {
211 if (put_reg(child, regno, data))
212 goto out_eio;
213 } else if (regno >= 21 && regno < 48) {
214 /* Convert long double format
215 * into internal fpu reg representation
216 */
217 if (FPU_IS_EMU && (regno < 45) && !(regno % 3)) {
218 data <<= 15;
219 data = (data & 0xffff0000) |
220 ((data & 0x0000ffff) >> 1);
221 }
222 child->thread.fp[regno - 21] = data;
223 } else
224 goto out_eio;
225 break;
226
227 case PTRACE_GETREGS: /* Get all gp regs from the child. */
228 for (i = 0; i < 19; i++) {
229 tmp = get_reg(child, i);
230 ret = put_user(tmp, datap);
231 if (ret)
232 break;
233 datap++;
234 }
235 break;
236
237 case PTRACE_SETREGS: /* Set all gp regs in the child. */
238 for (i = 0; i < 19; i++) {
239 ret = get_user(tmp, datap);
240 if (ret)
241 break;
242 if (i == PT_SR) {
243 tmp &= SR_MASK;
244 tmp |= get_reg(child, PT_SR) & ~SR_MASK;
245 }
246 put_reg(child, i, tmp);
247 datap++;
248 }
249 break;
250
251 case PTRACE_GETFPREGS: /* Get the child FPU state. */
252 if (copy_to_user(datap, &child->thread.fp,
253 sizeof(struct user_m68kfp_struct)))
254 ret = -EFAULT;
255 break;
256
257 case PTRACE_SETFPREGS: /* Set the child FPU state. */
258 if (copy_from_user(&child->thread.fp, datap,
259 sizeof(struct user_m68kfp_struct)))
260 ret = -EFAULT;
261 break;
262
263 case PTRACE_GET_THREAD_AREA:
264 ret = put_user(task_thread_info(child)->tp_value, datap);
265 break;
266
267 default:
268 ret = ptrace_request(child, request, addr, data);
269 break;
270 }
271
272 return ret;
273 out_eio:
274 return -EIO;
275 }
276
syscall_trace_enter(void)277 asmlinkage int syscall_trace_enter(void)
278 {
279 int ret = 0;
280
281 if (test_thread_flag(TIF_SYSCALL_TRACE))
282 ret = ptrace_report_syscall_entry(task_pt_regs(current));
283
284 if (secure_computing() == -1)
285 return -1;
286
287 return ret;
288 }
289
syscall_trace_leave(void)290 asmlinkage void syscall_trace_leave(void)
291 {
292 if (test_thread_flag(TIF_SYSCALL_TRACE))
293 ptrace_report_syscall_exit(task_pt_regs(current), 0);
294 }
295
296 #if defined(CONFIG_BINFMT_ELF_FDPIC) && defined(CONFIG_ELF_CORE)
297 /*
298 * Currently the only thing that needs to use regsets for m68k is the
299 * coredump support of the elf_fdpic loader. Implement the minimum
300 * definitions required for that.
301 */
m68k_regset_get(struct task_struct * target,const struct user_regset * regset,struct membuf to)302 static int m68k_regset_get(struct task_struct *target,
303 const struct user_regset *regset,
304 struct membuf to)
305 {
306 struct pt_regs *ptregs = task_pt_regs(target);
307 u32 uregs[ELF_NGREG];
308
309 ELF_CORE_COPY_REGS(uregs, ptregs);
310 return membuf_write(&to, uregs, sizeof(uregs));
311 }
312
313 enum m68k_regset {
314 REGSET_GPR,
315 #ifdef CONFIG_FPU
316 REGSET_FPU,
317 #endif
318 };
319
320 static const struct user_regset m68k_user_regsets[] = {
321 [REGSET_GPR] = {
322 .core_note_type = NT_PRSTATUS,
323 .n = ELF_NGREG,
324 .size = sizeof(u32),
325 .align = sizeof(u16),
326 .regset_get = m68k_regset_get,
327 },
328 #ifdef CONFIG_FPU
329 [REGSET_FPU] = {
330 .core_note_type = NT_PRFPREG,
331 .n = sizeof(struct user_m68kfp_struct) / sizeof(u32),
332 .size = sizeof(u32),
333 .align = sizeof(u32),
334 }
335 #endif /* CONFIG_FPU */
336 };
337
338 static const struct user_regset_view user_m68k_view = {
339 .name = "m68k",
340 .e_machine = EM_68K,
341 .ei_osabi = ELF_OSABI,
342 .regsets = m68k_user_regsets,
343 .n = ARRAY_SIZE(m68k_user_regsets)
344 };
345
task_user_regset_view(struct task_struct * task)346 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
347 {
348 return &user_m68k_view;
349 }
350 #endif /* CONFIG_BINFMT_ELF_FDPIC && CONFIG_ELF_CORE */
351