1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Traceprobe fetch helper inlines
4 */
5
6 static nokprobe_inline void
fetch_store_raw(unsigned long val,struct fetch_insn * code,void * buf)7 fetch_store_raw(unsigned long val, struct fetch_insn *code, void *buf)
8 {
9 switch (code->size) {
10 case 1:
11 *(u8 *)buf = (u8)val;
12 break;
13 case 2:
14 *(u16 *)buf = (u16)val;
15 break;
16 case 4:
17 *(u32 *)buf = (u32)val;
18 break;
19 case 8:
20 //TBD: 32bit signed
21 *(u64 *)buf = (u64)val;
22 break;
23 default:
24 *(unsigned long *)buf = val;
25 }
26 }
27
28 static nokprobe_inline void
fetch_apply_bitfield(struct fetch_insn * code,void * buf)29 fetch_apply_bitfield(struct fetch_insn *code, void *buf)
30 {
31 switch (code->basesize) {
32 case 1:
33 *(u8 *)buf <<= code->lshift;
34 *(u8 *)buf >>= code->rshift;
35 break;
36 case 2:
37 *(u16 *)buf <<= code->lshift;
38 *(u16 *)buf >>= code->rshift;
39 break;
40 case 4:
41 *(u32 *)buf <<= code->lshift;
42 *(u32 *)buf >>= code->rshift;
43 break;
44 case 8:
45 *(u64 *)buf <<= code->lshift;
46 *(u64 *)buf >>= code->rshift;
47 break;
48 }
49 }
50
51 /*
52 * These functions must be defined for each callsite.
53 * Return consumed dynamic data size (>= 0), or error (< 0).
54 * If dest is NULL, don't store result and return required dynamic data size.
55 */
56 static int
57 process_fetch_insn(struct fetch_insn *code, void *rec,
58 void *dest, void *base);
59 static nokprobe_inline int fetch_store_strlen(unsigned long addr);
60 static nokprobe_inline int
61 fetch_store_string(unsigned long addr, void *dest, void *base);
62 static nokprobe_inline int fetch_store_strlen_user(unsigned long addr);
63 static nokprobe_inline int
64 fetch_store_string_user(unsigned long addr, void *dest, void *base);
65 static nokprobe_inline int
66 probe_mem_read(void *dest, void *src, size_t size);
67 static nokprobe_inline int
68 probe_mem_read_user(void *dest, void *src, size_t size);
69
70 static nokprobe_inline int
fetch_store_symstrlen(unsigned long addr)71 fetch_store_symstrlen(unsigned long addr)
72 {
73 char namebuf[KSYM_SYMBOL_LEN];
74 int ret;
75
76 ret = sprint_symbol(namebuf, addr);
77 if (ret < 0)
78 return 0;
79
80 return ret + 1;
81 }
82
83 /*
84 * Fetch a null-terminated symbol string + offset. Caller MUST set *(u32 *)buf
85 * with max length and relative data location.
86 */
87 static nokprobe_inline int
fetch_store_symstring(unsigned long addr,void * dest,void * base)88 fetch_store_symstring(unsigned long addr, void *dest, void *base)
89 {
90 int maxlen = get_loc_len(*(u32 *)dest);
91 void *__dest;
92
93 if (unlikely(!maxlen))
94 return -ENOMEM;
95
96 __dest = get_loc_data(dest, base);
97
98 return sprint_symbol(__dest, addr);
99 }
100
101 /* From the 2nd stage, routine is same */
102 static nokprobe_inline int
process_fetch_insn_bottom(struct fetch_insn * code,unsigned long val,void * dest,void * base)103 process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val,
104 void *dest, void *base)
105 {
106 struct fetch_insn *s3 = NULL;
107 int total = 0, ret = 0, i = 0;
108 u32 loc = 0;
109 unsigned long lval = val;
110
111 stage2:
112 /* 2nd stage: dereference memory if needed */
113 do {
114 if (code->op == FETCH_OP_DEREF) {
115 lval = val;
116 ret = probe_mem_read(&val, (void *)val + code->offset,
117 sizeof(val));
118 } else if (code->op == FETCH_OP_UDEREF) {
119 lval = val;
120 ret = probe_mem_read_user(&val,
121 (void *)val + code->offset, sizeof(val));
122 } else
123 break;
124 if (ret)
125 return ret;
126 code++;
127 } while (1);
128
129 s3 = code;
130 stage3:
131 /* 3rd stage: store value to buffer */
132 if (unlikely(!dest)) {
133 switch (code->op) {
134 case FETCH_OP_ST_STRING:
135 ret = fetch_store_strlen(val + code->offset);
136 code++;
137 goto array;
138 case FETCH_OP_ST_USTRING:
139 ret = fetch_store_strlen_user(val + code->offset);
140 code++;
141 goto array;
142 case FETCH_OP_ST_SYMSTR:
143 ret = fetch_store_symstrlen(val + code->offset);
144 code++;
145 goto array;
146 default:
147 return -EILSEQ;
148 }
149 }
150
151 switch (code->op) {
152 case FETCH_OP_ST_RAW:
153 fetch_store_raw(val, code, dest);
154 break;
155 case FETCH_OP_ST_MEM:
156 probe_mem_read(dest, (void *)val + code->offset, code->size);
157 break;
158 case FETCH_OP_ST_UMEM:
159 probe_mem_read_user(dest, (void *)val + code->offset, code->size);
160 break;
161 case FETCH_OP_ST_STRING:
162 loc = *(u32 *)dest;
163 ret = fetch_store_string(val + code->offset, dest, base);
164 break;
165 case FETCH_OP_ST_USTRING:
166 loc = *(u32 *)dest;
167 ret = fetch_store_string_user(val + code->offset, dest, base);
168 break;
169 case FETCH_OP_ST_SYMSTR:
170 loc = *(u32 *)dest;
171 ret = fetch_store_symstring(val + code->offset, dest, base);
172 break;
173 default:
174 return -EILSEQ;
175 }
176 code++;
177
178 /* 4th stage: modify stored value if needed */
179 if (code->op == FETCH_OP_MOD_BF) {
180 fetch_apply_bitfield(code, dest);
181 code++;
182 }
183
184 array:
185 /* the last stage: Loop on array */
186 if (code->op == FETCH_OP_LP_ARRAY) {
187 if (ret < 0)
188 ret = 0;
189 total += ret;
190 if (++i < code->param) {
191 code = s3;
192 if (s3->op != FETCH_OP_ST_STRING &&
193 s3->op != FETCH_OP_ST_USTRING) {
194 dest += s3->size;
195 val += s3->size;
196 goto stage3;
197 }
198 code--;
199 val = lval + sizeof(char *);
200 if (dest) {
201 dest += sizeof(u32);
202 *(u32 *)dest = update_data_loc(loc, ret);
203 }
204 goto stage2;
205 }
206 code++;
207 ret = total;
208 }
209
210 return code->op == FETCH_OP_END ? ret : -EILSEQ;
211 }
212
213 /* Sum up total data length for dynamic arrays (strings) */
214 static nokprobe_inline int
__get_data_size(struct trace_probe * tp,struct pt_regs * regs)215 __get_data_size(struct trace_probe *tp, struct pt_regs *regs)
216 {
217 struct probe_arg *arg;
218 int i, len, ret = 0;
219
220 for (i = 0; i < tp->nr_args; i++) {
221 arg = tp->args + i;
222 if (unlikely(arg->dynamic)) {
223 len = process_fetch_insn(arg->code, regs, NULL, NULL);
224 if (len > 0)
225 ret += len;
226 }
227 }
228
229 return ret;
230 }
231
232 /* Store the value of each argument */
233 static nokprobe_inline void
store_trace_args(void * data,struct trace_probe * tp,void * rec,int header_size,int maxlen)234 store_trace_args(void *data, struct trace_probe *tp, void *rec,
235 int header_size, int maxlen)
236 {
237 struct probe_arg *arg;
238 void *base = data - header_size;
239 void *dyndata = data + tp->size;
240 u32 *dl; /* Data location */
241 int ret, i;
242
243 for (i = 0; i < tp->nr_args; i++) {
244 arg = tp->args + i;
245 dl = data + arg->offset;
246 /* Point the dynamic data area if needed */
247 if (unlikely(arg->dynamic))
248 *dl = make_data_loc(maxlen, dyndata - base);
249 ret = process_fetch_insn(arg->code, rec, dl, base);
250 if (arg->dynamic && likely(ret > 0)) {
251 dyndata += ret;
252 maxlen -= ret;
253 }
254 }
255 }
256
257 static inline int
print_probe_args(struct trace_seq * s,struct probe_arg * args,int nr_args,u8 * data,void * field)258 print_probe_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
259 u8 *data, void *field)
260 {
261 void *p;
262 int i, j;
263
264 for (i = 0; i < nr_args; i++) {
265 struct probe_arg *a = args + i;
266
267 trace_seq_printf(s, " %s=", a->name);
268 if (likely(!a->count)) {
269 if (!a->type->print(s, data + a->offset, field))
270 return -ENOMEM;
271 continue;
272 }
273 trace_seq_putc(s, '{');
274 p = data + a->offset;
275 for (j = 0; j < a->count; j++) {
276 if (!a->type->print(s, p, field))
277 return -ENOMEM;
278 trace_seq_putc(s, j == a->count - 1 ? '}' : ',');
279 p += a->type->size;
280 }
281 }
282 return 0;
283 }
284