xref: /kernel/linux/linux-6.6/arch/m68k/kernel/ptrace.c (revision 62306a36) 
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). */
50static 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 */
75static 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 */
99static 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 */
127static 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 */
137void ptrace_disable(struct task_struct *child)
138{
139	singlestep_disable(child);
140}
141
142void 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
150void 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
157void user_disable_single_step(struct task_struct *child)
158{
159	singlestep_disable(child);
160}
161
162long 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;
271out_eio:
272	return -EIO;
273}
274
275asmlinkage 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
288asmlinkage 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 */
300static 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
311enum m68k_regset {
312	REGSET_GPR,
313#ifdef CONFIG_FPU
314	REGSET_FPU,
315#endif
316};
317
318static 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
336static 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
344const 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