summaryrefslogtreecommitdiff
path: root/arch/h8300/kernel/ptrace_h.c
blob: f5ff3b794c8512ce430812fd07b5c85752294d79 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
/*
 *    ptrace cpu depend helper functions
 *
 *  Copyright 2003, 2015 Yoshinori Sato <ysato@users.sourceforge.jp>
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License.  See the file COPYING in the main directory of
 * this archive for more details.
 */

#include <linux/linkage.h>
#include <linux/sched/signal.h>
#include <asm/ptrace.h>

#define BREAKINST 0x5730 /* trapa #3 */

/* disable singlestep */
void user_disable_single_step(struct task_struct *child)
{
	if ((long)child->thread.breakinfo.addr != -1L) {
		*(child->thread.breakinfo.addr) = child->thread.breakinfo.inst;
		child->thread.breakinfo.addr = (unsigned short *)-1L;
	}
}

/* calculate next pc */
enum jump_type {none,	 /* normal instruction */
		jabs,	 /* absolute address jump */
		ind,	 /* indirect address jump */
		ret,	 /* return to subrutine */
		reg,	 /* register indexed jump */
		relb,	 /* pc relative jump (byte offset) */
		relw,	 /* pc relative jump (word offset) */
	       };

/* opcode decode table define
   ptn: opcode pattern
   msk: opcode bitmask
   len: instruction length (<0 next table index)
   jmp: jump operation mode */
struct optable {
	unsigned char bitpattern;
	unsigned char bitmask;
	signed char length;
	signed char type;
} __packed __aligned(1);

#define OPTABLE(ptn, msk, len, jmp)	\
	{				\
		.bitpattern = ptn,	\
		.bitmask    = msk,	\
		.length	    = len,	\
		.type	    = jmp,	\
	}

static const struct optable optable_0[] = {
	OPTABLE(0x00, 0xff,  1, none), /* 0x00 */
	OPTABLE(0x01, 0xff, -1, none), /* 0x01 */
	OPTABLE(0x02, 0xfe,  1, none), /* 0x02-0x03 */
	OPTABLE(0x04, 0xee,  1, none), /* 0x04-0x05/0x14-0x15 */
	OPTABLE(0x06, 0xfe,  1, none), /* 0x06-0x07 */
	OPTABLE(0x08, 0xea,  1, none), /* 0x08-0x09/0x0c-0x0d/0x18-0x19/0x1c-0x1d */
	OPTABLE(0x0a, 0xee,  1, none), /* 0x0a-0x0b/0x1a-0x1b */
	OPTABLE(0x0e, 0xee,  1, none), /* 0x0e-0x0f/0x1e-0x1f */
	OPTABLE(0x10, 0xfc,  1, none), /* 0x10-0x13 */
	OPTABLE(0x16, 0xfe,  1, none), /* 0x16-0x17 */
	OPTABLE(0x20, 0xe0,  1, none), /* 0x20-0x3f */
	OPTABLE(0x40, 0xf0,  1, relb), /* 0x40-0x4f */
	OPTABLE(0x50, 0xfc,  1, none), /* 0x50-0x53 */
	OPTABLE(0x54, 0xfd,  1, ret), /* 0x54/0x56 */
	OPTABLE(0x55, 0xff,  1, relb), /* 0x55 */
	OPTABLE(0x57, 0xff,  1, none), /* 0x57 */
	OPTABLE(0x58, 0xfb,  2, relw), /* 0x58/0x5c */
	OPTABLE(0x59, 0xfb,  1, reg), /* 0x59/0x5b */
	OPTABLE(0x5a, 0xfb,  2, jabs), /* 0x5a/0x5e */
	OPTABLE(0x5b, 0xfb,  2, ind), /* 0x5b/0x5f */
	OPTABLE(0x60, 0xe8,  1, none), /* 0x60-0x67/0x70-0x77 */
	OPTABLE(0x68, 0xfa,  1, none), /* 0x68-0x69/0x6c-0x6d */
	OPTABLE(0x6a, 0xfe, -2, none), /* 0x6a-0x6b */
	OPTABLE(0x6e, 0xfe,  2, none), /* 0x6e-0x6f */
	OPTABLE(0x78, 0xff,  4, none), /* 0x78 */
	OPTABLE(0x79, 0xff,  2, none), /* 0x79 */
	OPTABLE(0x7a, 0xff,  3, none), /* 0x7a */
	OPTABLE(0x7b, 0xff,  2, none), /* 0x7b */
	OPTABLE(0x7c, 0xfc,  2, none), /* 0x7c-0x7f */
	OPTABLE(0x80, 0x80,  1, none), /* 0x80-0xff */
};

static const struct optable optable_1[] = {
	OPTABLE(0x00, 0xff, -3, none), /* 0x0100 */
	OPTABLE(0x40, 0xf0, -3, none), /* 0x0140-0x14f */
	OPTABLE(0x80, 0xf0,  1, none), /* 0x0180-0x018f */
	OPTABLE(0xc0, 0xc0,  2, none), /* 0x01c0-0x01ff */
};

static const struct optable optable_2[] = {
	OPTABLE(0x00, 0x20,  2, none), /* 0x6a0?/0x6a8?/0x6b0?/0x6b8? */
	OPTABLE(0x20, 0x20,  3, none), /* 0x6a2?/0x6aa?/0x6b2?/0x6ba? */
};

static const struct optable optable_3[] = {
	OPTABLE(0x69, 0xfb,  2, none), /* 0x010069/0x01006d/014069/0x01406d */
	OPTABLE(0x6b, 0xff, -4, none), /* 0x01006b/0x01406b */
	OPTABLE(0x6f, 0xff,  3, none), /* 0x01006f/0x01406f */
	OPTABLE(0x78, 0xff,  5, none), /* 0x010078/0x014078 */
};

static const struct optable optable_4[] = {
/* 0x0100690?/0x01006d0?/0140690?/0x01406d0?/
   0x0100698?/0x01006d8?/0140698?/0x01406d8? */
	OPTABLE(0x00, 0x78, 3, none),
/* 0x0100692?/0x01006d2?/0140692?/0x01406d2?/
   0x010069a?/0x01006da?/014069a?/0x01406da? */
	OPTABLE(0x20, 0x78, 4, none),
};

static const struct optables_list {
	const struct optable *ptr;
	int size;
} optables[] = {
#define OPTABLES(no)                                                   \
	{                                                              \
		.ptr  = optable_##no,                                  \
		.size = sizeof(optable_##no) / sizeof(struct optable), \
	}
	OPTABLES(0),
	OPTABLES(1),
	OPTABLES(2),
	OPTABLES(3),
	OPTABLES(4),

};

const unsigned char condmask[] = {
	0x00, 0x40, 0x01, 0x04, 0x02, 0x08, 0x10, 0x20
};

static int isbranch(struct task_struct *task, int reson)
{
	unsigned char cond = h8300_get_reg(task, PT_CCR);

	/* encode complex conditions */
	/* B4: N^V
	   B5: Z|(N^V)
	   B6: C|Z */
	__asm__("bld #3,%w0\n\t"
		"bxor #1,%w0\n\t"
		"bst #4,%w0\n\t"
		"bor #2,%w0\n\t"
		"bst #5,%w0\n\t"
		"bld #2,%w0\n\t"
		"bor #0,%w0\n\t"
		"bst #6,%w0\n\t"
		: "=&r"(cond) : "0"(cond) : "cc");
	cond &= condmask[reson >> 1];
	if (!(reson & 1))
		return cond == 0;
	else
		return cond != 0;
}

static unsigned short *decode(struct task_struct *child,
			      const struct optable *op,
			      char *fetch_p, unsigned short *pc,
			      unsigned char inst)
{
	unsigned long addr;
	unsigned long *sp;
	int regno;

	switch (op->type) {
	case none:
		return (unsigned short *)pc + op->length;
	case jabs:
		addr = *(unsigned long *)pc;
		return (unsigned short *)(addr & 0x00ffffff);
	case ind:
		addr = *pc & 0xff;
		return (unsigned short *)(*(unsigned long *)addr);
	case ret:
		sp = (unsigned long *)h8300_get_reg(child, PT_USP);
		/* user stack frames
		   |   er0  | temporary saved
		   +--------+
		   |   exp  | exception stack frames
		   +--------+
		   | ret pc | userspace return address
		*/
		return (unsigned short *)(*(sp+2) & 0x00ffffff);
	case reg:
		regno = (*pc >> 4) & 0x07;
		if (regno == 0)
			addr = h8300_get_reg(child, PT_ER0);
		else
			addr = h8300_get_reg(child, regno-1 + PT_ER1);
		return (unsigned short *)addr;
	case relb:
		if (inst == 0x55 || isbranch(child, inst & 0x0f))
			pc = (unsigned short *)((unsigned long)pc +
						((signed char)(*fetch_p)));
		return pc+1; /* skip myself */
	case relw:
		if (inst == 0x5c || isbranch(child, (*fetch_p & 0xf0) >> 4))
			pc = (unsigned short *)((unsigned long)pc +
						((signed short)(*(pc+1))));
		return pc+2; /* skip myself */
	default:
		return NULL;
	}
}

static unsigned short *nextpc(struct task_struct *child, unsigned short *pc)
{
	const struct optable *op;
	unsigned char *fetch_p;
	int op_len;
	unsigned char inst;

	op = optables[0].ptr;
	op_len = optables[0].size;
	fetch_p = (unsigned char *)pc;
	inst = *fetch_p++;
	do {
		if ((inst & op->bitmask) == op->bitpattern) {
			if (op->length < 0) {
				op = optables[-op->length].ptr;
				op_len = optables[-op->length].size + 1;
				inst = *fetch_p++;
			} else
				return decode(child, op, fetch_p, pc, inst);
		} else
			op++;
	} while (--op_len > 0);
	return NULL;
}

/* Set breakpoint(s) to simulate a single step from the current PC.  */

void user_enable_single_step(struct task_struct *child)
{
	unsigned short *next;

	next = nextpc(child, (unsigned short *)h8300_get_reg(child, PT_PC));
	child->thread.breakinfo.addr = next;
	child->thread.breakinfo.inst = *next;
	*next = BREAKINST;
}

asmlinkage void trace_trap(unsigned long bp)
{
	if ((unsigned long)current->thread.breakinfo.addr == bp) {
		user_disable_single_step(current);
		force_sig(SIGTRAP, current);
	} else
		force_sig(SIGILL, current);
}