15db45a03b04560fc177e799db6d591c56501c5e
[releases.git] / ptrace_h.c
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 */
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
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
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
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
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
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 }