1 /*
2 * Copyright (C) 2017 Oracle.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
16 */
17
18 /*
19 * Take a look at request_threaded_irq(). It takes thread_fn and dev_id. Then
20 * it does:
21 *
22 * action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
23 * action->thread_fn = thread_fn;
24 * action->dev_id = dev_id;
25 *
26 * It doesn't ever pass action back to the higher levels, but instead registers
27 * it with the lower levels.
28 *
29 * The kzalloc() allocation creates a new mtag. We don't know at this point
30 * what "thread_fn" and "dev_id" are because they come from many different
31 * sources.
32 *
33 * So what we do is we pass the information back to the callers that thread_fn
34 * and dev_id are stored as a specific mtag data. Then when the callers *do*
35 * know what values are passed they create an mtag_alias. An mtag_alias is a
36 * many to one relationship. Then they store that in mtag_data using the
37 * mtag_alias.
38 *
39 */
40
41 #include "smatch.h"
42 #include "smatch_extra.h"
43 #include "smatch_slist.h"
44
45 static int my_id;
46
47 struct tag_assign_info {
48 mtag_t tag;
49 int offset;
50 };
51 ALLOCATOR(tag_assign_info, "tag name offset");
52
53 static struct smatch_state *alloc_tag_data_state(mtag_t tag, char *name, int offset)
54 {
55 struct smatch_state *state;
56 struct tag_assign_info *data;
57
58 data = __alloc_tag_assign_info(0);
59 data->tag = tag;
60 data->offset = offset;
61
62 state = __alloc_smatch_state(0);
63 state->name = alloc_sname(name);
64 state->data = data;
65 return state;
66 }
67
68 struct smatch_state *merge_tag_info(struct smatch_state *s1, struct smatch_state *s2)
69 {
70 /* Basically ignore undefined states */
71 if (s1 == &undefined)
72 return s2;
73 if (s2 == &undefined)
74 return s1;
75
76 return &merged;
77 }
78
79 static bool is_local_var(struct expression *expr)
80 {
81 struct symbol *sym;
82
83 if (!expr || expr->type != EXPR_SYMBOL)
84 return false;
85 sym = expr->symbol;
86 if (!(sym->ctype.modifiers & MOD_TOPLEVEL))
87 return true;
88 return false;
89 }
90
91 static void match_assign(struct expression *expr)
92 {
93 struct expression *left;
94 struct symbol *right_sym;
95 char *name;
96 mtag_t tag;
97 int offset;
98 int param;
99
100 if (expr->op != '=')
101 return;
102 left = strip_expr(expr->left);
103 if (is_local_var(left))
104 return;
105 right_sym = expr_to_sym(expr->right);
106 if (!right_sym)
107 return;
108
109 param = get_param_num_from_sym(right_sym);
110 if (param < 0)
111 return;
112 // FIXME: modify param_has_filter_data() to take a name/sym
113 if (!expr_to_mtag_offset(left, &tag, &offset))
114 return;
115 name = expr_to_str(left);
116 if (!name)
117 return;
118 set_state_expr(my_id, expr->right, alloc_tag_data_state(tag, name, offset));
119 free_string(name);
120 }
121
122 static void propogate_assignment(struct expression *expr, mtag_t tag, int offset, int param, char *key)
123 {
124 struct expression *arg;
125 int orig_param;
126 char buf[32];
127 char *name;
128 struct symbol *sym;
129
130 arg = get_argument_from_call_expr(expr->args, param);
131 if (!arg)
132 return;
133 name = get_variable_from_key(arg, key, &sym);
134 if (!name || !sym)
135 goto free;
136
137 orig_param = get_param_num_from_sym(sym);
138 if (orig_param < 0)
139 goto free;
140
141 snprintf(buf, sizeof(buf), "$->[%d]", offset);
142 set_state(my_id, name, sym, alloc_tag_data_state(tag, buf, offset));
143 free:
144 free_string(name);
145 }
146
147 static void assign_to_alias(struct expression *expr, int param, mtag_t tag, int offset, char *key)
148 {
149 struct expression *arg, *gen_expr;
150 struct range_list *rl;
151 mtag_t arg_tag;
152 mtag_t alias;
153 int arg_offset;
154
155 arg = get_argument_from_call_expr(expr->args, param);
156 if (!arg)
157 return;
158
159 gen_expr = gen_expression_from_key(arg, key);
160 if (!gen_expr)
161 return;
162
163 get_absolute_rl(gen_expr, &rl);
164
165 if (!create_mtag_alias(tag, expr, &alias))
166 return;
167
168 // insert_mtag_data(alias, offset, rl);
169
170 // FIXME: is arg_offset handled correctly?
171 if (expr_to_mtag_offset(gen_expr, &arg_tag, &arg_offset) && arg_offset == 0)
172 sql_insert_mtag_map(arg_tag, -offset, alias);
173 }
174
175 static void call_does_mtag_assign(struct expression *expr, int param, char *key, char *value)
176 {
177 char *p;
178 mtag_t tag;
179 int offset;
180
181 while (expr->type == EXPR_ASSIGNMENT)
182 expr = strip_expr(expr->right);
183 if (expr->type != EXPR_CALL)
184 return;
185
186 tag = strtoul(value, NULL, 10);
187 p = strchr(value, '+');
188 if (!p)
189 return;
190 offset = atoi(p + 1);
191
192 // save_mtag_to_map(expr, tag, offset, param, key, value);
193 propogate_assignment(expr, tag, offset, param, key);
194 assign_to_alias(expr, param, tag, offset, key);
195 }
196
197 static void print_stored_to_mtag(int return_id, char *return_ranges, struct expression *expr)
198 {
199 struct sm_state *sm;
200 struct tag_assign_info *data;
201 char buf[256];
202 const char *param_name;
203 int param;
204
205 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
206 if (!sm->state->data)
207 continue;
208
209 param = get_param_num_from_sym(sm->sym);
210 if (param < 0)
211 continue;
212 param_name = get_param_name(sm);
213 if (!param_name)
214 continue;
215
216 data = sm->state->data;
217 snprintf(buf, sizeof(buf), "%lld+%d", data->tag, data->offset);
218 sql_insert_return_states(return_id, return_ranges, MTAG_ASSIGN, param, param_name, buf);
219 } END_FOR_EACH_SM(sm);
220 }
221
222 void register_param_to_mtag_data(int id)
223 {
224 my_id = id;
225
226 set_dynamic_states(my_id);
227 add_hook(&match_assign, ASSIGNMENT_HOOK);
228 select_return_states_hook(MTAG_ASSIGN, &call_does_mtag_assign);
229 add_merge_hook(my_id, &merge_tag_info);
230 add_split_return_callback(&print_stored_to_mtag);
231 }
232