1 /*
2 * ptrace cpu depend helper functions
3 *
4 * Copyright 2003, 2015 Yoshinori Sato <ysato@users.sourceforge.jp>
5 *
6 * This file is subject to the terms and conditions of the GNU General
7 * Public License. See the file COPYING in the main directory of
8 * this archive for more details.
9 */
10
11 #include <linux/linkage.h>
12 #include <linux/sched/signal.h>
13 #include <asm/ptrace.h>
14
15 #define BREAKINST 0x5730 /* trapa #3 */
16
17 /* disable singlestep */
user_disable_single_step(struct task_struct * child)18 void user_disable_single_step(struct task_struct *child)
19 {
20 if ((long)child->thread.breakinfo.addr != -1L) {
21 *(child->thread.breakinfo.addr) = child->thread.breakinfo.inst;
22 child->thread.breakinfo.addr = (unsigned short *)-1L;
23 }
24 }
25
26 /* calculate next pc */
27 enum jump_type {none, /* normal instruction */
28 jabs, /* absolute address jump */
29 ind, /* indirect address jump */
30 ret, /* return to subrutine */
31 reg, /* register indexed jump */
32 relb, /* pc relative jump (byte offset) */
33 relw, /* pc relative jump (word offset) */
34 };
35
36 /* opcode decode table define
37 ptn: opcode pattern
38 msk: opcode bitmask
39 len: instruction length (<0 next table index)
40 jmp: jump operation mode */
41 struct optable {
42 unsigned char bitpattern;
43 unsigned char bitmask;
44 signed char length;
45 signed char type;
46 } __packed __aligned(1);
47
48 #define OPTABLE(ptn, msk, len, jmp) \
49 { \
50 .bitpattern = ptn, \
51 .bitmask = msk, \
52 .length = len, \
53 .type = jmp, \
54 }
55
56 static const struct optable optable_0[] = {
57 OPTABLE(0x00, 0xff, 1, none), /* 0x00 */
58 OPTABLE(0x01, 0xff, -1, none), /* 0x01 */
59 OPTABLE(0x02, 0xfe, 1, none), /* 0x02-0x03 */
60 OPTABLE(0x04, 0xee, 1, none), /* 0x04-0x05/0x14-0x15 */
61 OPTABLE(0x06, 0xfe, 1, none), /* 0x06-0x07 */
62 OPTABLE(0x08, 0xea, 1, none), /* 0x08-0x09/0x0c-0x0d/0x18-0x19/0x1c-0x1d */
63 OPTABLE(0x0a, 0xee, 1, none), /* 0x0a-0x0b/0x1a-0x1b */
64 OPTABLE(0x0e, 0xee, 1, none), /* 0x0e-0x0f/0x1e-0x1f */
65 OPTABLE(0x10, 0xfc, 1, none), /* 0x10-0x13 */
66 OPTABLE(0x16, 0xfe, 1, none), /* 0x16-0x17 */
67 OPTABLE(0x20, 0xe0, 1, none), /* 0x20-0x3f */
68 OPTABLE(0x40, 0xf0, 1, relb), /* 0x40-0x4f */
69 OPTABLE(0x50, 0xfc, 1, none), /* 0x50-0x53 */
70 OPTABLE(0x54, 0xfd, 1, ret), /* 0x54/0x56 */
71 OPTABLE(0x55, 0xff, 1, relb), /* 0x55 */
72 OPTABLE(0x57, 0xff, 1, none), /* 0x57 */
73 OPTABLE(0x58, 0xfb, 2, relw), /* 0x58/0x5c */
74 OPTABLE(0x59, 0xfb, 1, reg), /* 0x59/0x5b */
75 OPTABLE(0x5a, 0xfb, 2, jabs), /* 0x5a/0x5e */
76 OPTABLE(0x5b, 0xfb, 2, ind), /* 0x5b/0x5f */
77 OPTABLE(0x60, 0xe8, 1, none), /* 0x60-0x67/0x70-0x77 */
78 OPTABLE(0x68, 0xfa, 1, none), /* 0x68-0x69/0x6c-0x6d */
79 OPTABLE(0x6a, 0xfe, -2, none), /* 0x6a-0x6b */
80 OPTABLE(0x6e, 0xfe, 2, none), /* 0x6e-0x6f */
81 OPTABLE(0x78, 0xff, 4, none), /* 0x78 */
82 OPTABLE(0x79, 0xff, 2, none), /* 0x79 */
83 OPTABLE(0x7a, 0xff, 3, none), /* 0x7a */
84 OPTABLE(0x7b, 0xff, 2, none), /* 0x7b */
85 OPTABLE(0x7c, 0xfc, 2, none), /* 0x7c-0x7f */
86 OPTABLE(0x80, 0x80, 1, none), /* 0x80-0xff */
87 };
88
89 static const struct optable optable_1[] = {
90 OPTABLE(0x00, 0xff, -3, none), /* 0x0100 */
91 OPTABLE(0x40, 0xf0, -3, none), /* 0x0140-0x14f */
92 OPTABLE(0x80, 0xf0, 1, none), /* 0x0180-0x018f */
93 OPTABLE(0xc0, 0xc0, 2, none), /* 0x01c0-0x01ff */
94 };
95
96 static const struct optable optable_2[] = {
97 OPTABLE(0x00, 0x20, 2, none), /* 0x6a0?/0x6a8?/0x6b0?/0x6b8? */
98 OPTABLE(0x20, 0x20, 3, none), /* 0x6a2?/0x6aa?/0x6b2?/0x6ba? */
99 };
100
101 static const struct optable optable_3[] = {
102 OPTABLE(0x69, 0xfb, 2, none), /* 0x010069/0x01006d/014069/0x01406d */
103 OPTABLE(0x6b, 0xff, -4, none), /* 0x01006b/0x01406b */
104 OPTABLE(0x6f, 0xff, 3, none), /* 0x01006f/0x01406f */
105 OPTABLE(0x78, 0xff, 5, none), /* 0x010078/0x014078 */
106 };
107
108 static const struct optable optable_4[] = {
109 /* 0x0100690?/0x01006d0?/0140690?/0x01406d0?/
110 0x0100698?/0x01006d8?/0140698?/0x01406d8? */
111 OPTABLE(0x00, 0x78, 3, none),
112 /* 0x0100692?/0x01006d2?/0140692?/0x01406d2?/
113 0x010069a?/0x01006da?/014069a?/0x01406da? */
114 OPTABLE(0x20, 0x78, 4, none),
115 };
116
117 static const struct optables_list {
118 const struct optable *ptr;
119 int size;
120 } optables[] = {
121 #define OPTABLES(no) \
122 { \
123 .ptr = optable_##no, \
124 .size = sizeof(optable_##no) / sizeof(struct optable), \
125 }
126 OPTABLES(0),
127 OPTABLES(1),
128 OPTABLES(2),
129 OPTABLES(3),
130 OPTABLES(4),
131
132 };
133
134 const unsigned char condmask[] = {
135 0x00, 0x40, 0x01, 0x04, 0x02, 0x08, 0x10, 0x20
136 };
137
isbranch(struct task_struct * task,int reson)138 static int isbranch(struct task_struct *task, int reson)
139 {
140 unsigned char cond = h8300_get_reg(task, PT_CCR);
141
142 /* encode complex conditions */
143 /* B4: N^V
144 B5: Z|(N^V)
145 B6: C|Z */
146 __asm__("bld #3,%w0\n\t"
147 "bxor #1,%w0\n\t"
148 "bst #4,%w0\n\t"
149 "bor #2,%w0\n\t"
150 "bst #5,%w0\n\t"
151 "bld #2,%w0\n\t"
152 "bor #0,%w0\n\t"
153 "bst #6,%w0\n\t"
154 : "=&r"(cond) : "0"(cond) : "cc");
155 cond &= condmask[reson >> 1];
156 if (!(reson & 1))
157 return cond == 0;
158 else
159 return cond != 0;
160 }
161
decode(struct task_struct * child,const struct optable * op,char * fetch_p,unsigned short * pc,unsigned char inst)162 static unsigned short *decode(struct task_struct *child,
163 const struct optable *op,
164 char *fetch_p, unsigned short *pc,
165 unsigned char inst)
166 {
167 unsigned long addr;
168 unsigned long *sp;
169 int regno;
170
171 switch (op->type) {
172 case none:
173 return (unsigned short *)pc + op->length;
174 case jabs:
175 addr = *(unsigned long *)pc;
176 return (unsigned short *)(addr & 0x00ffffff);
177 case ind:
178 addr = *pc & 0xff;
179 return (unsigned short *)(*(unsigned long *)addr);
180 case ret:
181 sp = (unsigned long *)h8300_get_reg(child, PT_USP);
182 /* user stack frames
183 | er0 | temporary saved
184 +--------+
185 | exp | exception stack frames
186 +--------+
187 | ret pc | userspace return address
188 */
189 return (unsigned short *)(*(sp+2) & 0x00ffffff);
190 case reg:
191 regno = (*pc >> 4) & 0x07;
192 if (regno == 0)
193 addr = h8300_get_reg(child, PT_ER0);
194 else
195 addr = h8300_get_reg(child, regno-1 + PT_ER1);
196 return (unsigned short *)addr;
197 case relb:
198 if (inst == 0x55 || isbranch(child, inst & 0x0f))
199 pc = (unsigned short *)((unsigned long)pc +
200 ((signed char)(*fetch_p)));
201 return pc+1; /* skip myself */
202 case relw:
203 if (inst == 0x5c || isbranch(child, (*fetch_p & 0xf0) >> 4))
204 pc = (unsigned short *)((unsigned long)pc +
205 ((signed short)(*(pc+1))));
206 return pc+2; /* skip myself */
207 default:
208 return NULL;
209 }
210 }
211
nextpc(struct task_struct * child,unsigned short * pc)212 static unsigned short *nextpc(struct task_struct *child, unsigned short *pc)
213 {
214 const struct optable *op;
215 unsigned char *fetch_p;
216 int op_len;
217 unsigned char inst;
218
219 op = optables[0].ptr;
220 op_len = optables[0].size;
221 fetch_p = (unsigned char *)pc;
222 inst = *fetch_p++;
223 do {
224 if ((inst & op->bitmask) == op->bitpattern) {
225 if (op->length < 0) {
226 op = optables[-op->length].ptr;
227 op_len = optables[-op->length].size + 1;
228 inst = *fetch_p++;
229 } else
230 return decode(child, op, fetch_p, pc, inst);
231 } else
232 op++;
233 } while (--op_len > 0);
234 return NULL;
235 }
236
237 /* Set breakpoint(s) to simulate a single step from the current PC. */
238
user_enable_single_step(struct task_struct * child)239 void user_enable_single_step(struct task_struct *child)
240 {
241 unsigned short *next;
242
243 next = nextpc(child, (unsigned short *)h8300_get_reg(child, PT_PC));
244 child->thread.breakinfo.addr = next;
245 child->thread.breakinfo.inst = *next;
246 *next = BREAKINST;
247 }
248
trace_trap(unsigned long bp)249 asmlinkage void trace_trap(unsigned long bp)
250 {
251 if ((unsigned long)current->thread.breakinfo.addr == bp) {
252 user_disable_single_step(current);
253 force_sig(SIGTRAP);
254 } else
255 force_sig(SIGILL);
256 }
257
