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). */
52static 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 */
77static 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 */
101static 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 */
129static 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 */
139void ptrace_disable(struct task_struct *child)
140{
141	singlestep_disable(child);
142}
143
144void 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
152void 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
159void user_disable_single_step(struct task_struct *child)
160{
161	singlestep_disable(child);
162}
163
164long 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;
273out_eio:
274	return -EIO;
275}
276
277asmlinkage 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
290asmlinkage 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 */
302static 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
313enum m68k_regset {
314	REGSET_GPR,
315#ifdef CONFIG_FPU
316	REGSET_FPU,
317#endif
318};
319
320static 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
338static 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
346const 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