xref: /openbmc/linux/arch/m68k/kernel/ptrace.c (revision 6baaade1)
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 /*
30  * does not yet catch signals sent when the child dies.
31  * in exit.c or in signal.c.
32  */
33 
34 /* determines which bits in the SR the user has access to. */
35 /* 1 = access 0 = no access */
36 #define SR_MASK 0x001f
37 
38 /* sets the trace bits. */
39 #define TRACE_BITS 0xC000
40 #define T1_BIT 0x8000
41 #define T0_BIT 0x4000
42 
43 /* Find the stack offset for a register, relative to thread.esp0. */
44 #define PT_REG(reg)	((long)&((struct pt_regs *)0)->reg)
45 #define SW_REG(reg)	((long)&((struct switch_stack *)0)->reg \
46 			 - sizeof(struct switch_stack))
47 /* Mapping from PT_xxx to the stack offset at which the register is
48    saved.  Notice that usp has no stack-slot and needs to be treated
49    specially (see get_reg/put_reg below). */
50 static const int regoff[] = {
51 	[0]	= PT_REG(d1),
52 	[1]	= PT_REG(d2),
53 	[2]	= PT_REG(d3),
54 	[3]	= PT_REG(d4),
55 	[4]	= PT_REG(d5),
56 	[5]	= SW_REG(d6),
57 	[6]	= SW_REG(d7),
58 	[7]	= PT_REG(a0),
59 	[8]	= PT_REG(a1),
60 	[9]	= PT_REG(a2),
61 	[10]	= SW_REG(a3),
62 	[11]	= SW_REG(a4),
63 	[12]	= SW_REG(a5),
64 	[13]	= SW_REG(a6),
65 	[14]	= PT_REG(d0),
66 	[15]	= -1,
67 	[16]	= PT_REG(orig_d0),
68 	[17]	= PT_REG(sr),
69 	[18]	= PT_REG(pc),
70 };
71 
72 /*
73  * Get contents of register REGNO in task TASK.
74  */
get_reg(struct task_struct * task,int regno)75 static inline long get_reg(struct task_struct *task, int regno)
76 {
77 	unsigned long *addr;
78 
79 	if (regno == PT_USP)
80 		addr = &task->thread.usp;
81 	else if (regno < ARRAY_SIZE(regoff))
82 		addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
83 	else
84 		return 0;
85 	/* Need to take stkadj into account. */
86 	if (regno == PT_SR || regno == PT_PC) {
87 		long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj));
88 		addr = (unsigned long *) ((unsigned long)addr + stkadj);
89 		/* The sr is actually a 16 bit register.  */
90 		if (regno == PT_SR)
91 			return *(unsigned short *)addr;
92 	}
93 	return *addr;
94 }
95 
96 /*
97  * Write contents of register REGNO in task TASK.
98  */
put_reg(struct task_struct * task,int regno,unsigned long data)99 static inline int put_reg(struct task_struct *task, int regno,
100 			  unsigned long data)
101 {
102 	unsigned long *addr;
103 
104 	if (regno == PT_USP)
105 		addr = &task->thread.usp;
106 	else if (regno < ARRAY_SIZE(regoff))
107 		addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
108 	else
109 		return -1;
110 	/* Need to take stkadj into account. */
111 	if (regno == PT_SR || regno == PT_PC) {
112 		long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj));
113 		addr = (unsigned long *) ((unsigned long)addr + stkadj);
114 		/* The sr is actually a 16 bit register.  */
115 		if (regno == PT_SR) {
116 			*(unsigned short *)addr = data;
117 			return 0;
118 		}
119 	}
120 	*addr = data;
121 	return 0;
122 }
123 
124 /*
125  * Make sure the single step bit is not set.
126  */
singlestep_disable(struct task_struct * child)127 static inline void singlestep_disable(struct task_struct *child)
128 {
129 	unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
130 	put_reg(child, PT_SR, tmp);
131 	clear_tsk_thread_flag(child, TIF_DELAYED_TRACE);
132 }
133 
134 /*
135  * Called by kernel/ptrace.c when detaching..
136  */
ptrace_disable(struct task_struct * child)137 void ptrace_disable(struct task_struct *child)
138 {
139 	singlestep_disable(child);
140 }
141 
user_enable_single_step(struct task_struct * child)142 void user_enable_single_step(struct task_struct *child)
143 {
144 	unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
145 	put_reg(child, PT_SR, tmp | T1_BIT);
146 	set_tsk_thread_flag(child, TIF_DELAYED_TRACE);
147 }
148 
149 #ifdef CONFIG_MMU
user_enable_block_step(struct task_struct * child)150 void user_enable_block_step(struct task_struct *child)
151 {
152 	unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
153 	put_reg(child, PT_SR, tmp | T0_BIT);
154 }
155 #endif
156 
user_disable_single_step(struct task_struct * child)157 void user_disable_single_step(struct task_struct *child)
158 {
159 	singlestep_disable(child);
160 }
161 
arch_ptrace(struct task_struct * child,long request,unsigned long addr,unsigned long data)162 long arch_ptrace(struct task_struct *child, long request,
163 		 unsigned long addr, unsigned long data)
164 {
165 	unsigned long tmp;
166 	int i, ret = 0;
167 	int regno = addr >> 2; /* temporary hack. */
168 	unsigned long __user *datap = (unsigned long __user *) data;
169 
170 	switch (request) {
171 	/* read the word at location addr in the USER area. */
172 	case PTRACE_PEEKUSR:
173 		if (addr & 3)
174 			goto out_eio;
175 
176 		if (regno >= 0 && regno < 19) {
177 			tmp = get_reg(child, regno);
178 		} else if (regno >= 21 && regno < 49) {
179 			tmp = child->thread.fp[regno - 21];
180 			/* Convert internal fpu reg representation
181 			 * into long double format
182 			 */
183 			if (FPU_IS_EMU && (regno < 45) && !(regno % 3))
184 				tmp = ((tmp & 0xffff0000) << 15) |
185 				      ((tmp & 0x0000ffff) << 16);
186 #ifndef CONFIG_MMU
187 		} else if (regno == 49) {
188 			tmp = child->mm->start_code;
189 		} else if (regno == 50) {
190 			tmp = child->mm->start_data;
191 		} else if (regno == 51) {
192 			tmp = child->mm->end_code;
193 #endif
194 		} else
195 			goto out_eio;
196 		ret = put_user(tmp, datap);
197 		break;
198 
199 	case PTRACE_POKEUSR:
200 	/* write the word at location addr in the USER area */
201 		if (addr & 3)
202 			goto out_eio;
203 
204 		if (regno == PT_SR) {
205 			data &= SR_MASK;
206 			data |= get_reg(child, PT_SR) & ~SR_MASK;
207 		}
208 		if (regno >= 0 && regno < 19) {
209 			if (put_reg(child, regno, data))
210 				goto out_eio;
211 		} else if (regno >= 21 && regno < 48) {
212 			/* Convert long double format
213 			 * into internal fpu reg representation
214 			 */
215 			if (FPU_IS_EMU && (regno < 45) && !(regno % 3)) {
216 				data <<= 15;
217 				data = (data & 0xffff0000) |
218 				       ((data & 0x0000ffff) >> 1);
219 			}
220 			child->thread.fp[regno - 21] = data;
221 		} else
222 			goto out_eio;
223 		break;
224 
225 	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
226 		for (i = 0; i < 19; i++) {
227 			tmp = get_reg(child, i);
228 			ret = put_user(tmp, datap);
229 			if (ret)
230 				break;
231 			datap++;
232 		}
233 		break;
234 
235 	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
236 		for (i = 0; i < 19; i++) {
237 			ret = get_user(tmp, datap);
238 			if (ret)
239 				break;
240 			if (i == PT_SR) {
241 				tmp &= SR_MASK;
242 				tmp |= get_reg(child, PT_SR) & ~SR_MASK;
243 			}
244 			put_reg(child, i, tmp);
245 			datap++;
246 		}
247 		break;
248 
249 	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
250 		if (copy_to_user(datap, &child->thread.fp,
251 				 sizeof(struct user_m68kfp_struct)))
252 			ret = -EFAULT;
253 		break;
254 
255 	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
256 		if (copy_from_user(&child->thread.fp, datap,
257 				   sizeof(struct user_m68kfp_struct)))
258 			ret = -EFAULT;
259 		break;
260 
261 	case PTRACE_GET_THREAD_AREA:
262 		ret = put_user(task_thread_info(child)->tp_value, datap);
263 		break;
264 
265 	default:
266 		ret = ptrace_request(child, request, addr, data);
267 		break;
268 	}
269 
270 	return ret;
271 out_eio:
272 	return -EIO;
273 }
274 
syscall_trace_enter(void)275 asmlinkage int syscall_trace_enter(void)
276 {
277 	int ret = 0;
278 
279 	if (test_thread_flag(TIF_SYSCALL_TRACE))
280 		ret = ptrace_report_syscall_entry(task_pt_regs(current));
281 
282 	if (secure_computing() == -1)
283 		return -1;
284 
285 	return ret;
286 }
287 
syscall_trace_leave(void)288 asmlinkage void syscall_trace_leave(void)
289 {
290 	if (test_thread_flag(TIF_SYSCALL_TRACE))
291 		ptrace_report_syscall_exit(task_pt_regs(current), 0);
292 }
293 
294 #if defined(CONFIG_BINFMT_ELF_FDPIC) && defined(CONFIG_ELF_CORE)
295 /*
296  * Currently the only thing that needs to use regsets for m68k is the
297  * coredump support of the elf_fdpic loader. Implement the minimum
298  * definitions required for that.
299  */
m68k_regset_get(struct task_struct * target,const struct user_regset * regset,struct membuf to)300 static int m68k_regset_get(struct task_struct *target,
301 			   const struct user_regset *regset,
302 			   struct membuf to)
303 {
304 	struct pt_regs *ptregs = task_pt_regs(target);
305 	u32 uregs[ELF_NGREG];
306 
307 	ELF_CORE_COPY_REGS(uregs, ptregs);
308 	return membuf_write(&to, uregs, sizeof(uregs));
309 }
310 
311 enum m68k_regset {
312 	REGSET_GPR,
313 #ifdef CONFIG_FPU
314 	REGSET_FPU,
315 #endif
316 };
317 
318 static const struct user_regset m68k_user_regsets[] = {
319 	[REGSET_GPR] = {
320 		.core_note_type = NT_PRSTATUS,
321 		.n = ELF_NGREG,
322 		.size = sizeof(u32),
323 		.align = sizeof(u16),
324 		.regset_get = m68k_regset_get,
325 	},
326 #ifdef CONFIG_FPU
327 	[REGSET_FPU] = {
328 		.core_note_type = NT_PRFPREG,
329 		.n = sizeof(struct user_m68kfp_struct) / sizeof(u32),
330 		.size = sizeof(u32),
331 		.align = sizeof(u32),
332 	}
333 #endif /* CONFIG_FPU */
334 };
335 
336 static const struct user_regset_view user_m68k_view = {
337 	.name = "m68k",
338 	.e_machine = EM_68K,
339 	.ei_osabi = ELF_OSABI,
340 	.regsets = m68k_user_regsets,
341 	.n = ARRAY_SIZE(m68k_user_regsets)
342 };
343 
task_user_regset_view(struct task_struct * task)344 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
345 {
346 	return &user_m68k_view;
347 }
348 #endif /* CONFIG_BINFMT_ELF_FDPIC && CONFIG_ELF_CORE */
349