1 /*
2 * Copyright (C) 2018 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 #include <stdlib.h>
19 #include "parse.h"
20 #include "smatch.h"
21 #include "smatch_slist.h"
22 #include "smatch_extra.h"
23
24 static int my_id;
25 static int barrier_id;
26
27 STATE(nospec);
28
29 static bool in_nospec_stmt;
30
31 static struct smatch_state *unmatched_state(struct sm_state *sm)
32 {
33 struct range_list *rl;
34
35 if (__in_function_def && !get_user_rl_var_sym(sm->name, sm->sym, &rl))
36 return &nospec;
37 return &undefined;
38 }
39
40 bool is_nospec(struct expression *expr)
41 {
42 char *macro;
43
44 if (in_nospec_stmt)
45 return true;
46 if (!expr)
47 return false;
48 if (get_state_expr(my_id, expr) == &nospec)
49 return true;
50 macro = get_macro_name(expr->pos);
51 if (macro && strcmp(macro, "array_index_nospec") == 0)
52 return true;
53 return false;
54 }
55
56 static void nospec_assign(struct expression *expr)
57 {
58 if (is_nospec(expr->right))
59 set_state_expr(my_id, expr->left, &nospec);
60 }
61
62 static void set_param_nospec(const char *name, struct symbol *sym, char *key, char *value)
63 {
64 char fullname[256];
65
66 if (strcmp(key, "*$") == 0)
67 snprintf(fullname, sizeof(fullname), "*%s", name);
68 else if (strncmp(key, "$", 1) == 0)
69 snprintf(fullname, 256, "%s%s", name, key + 1);
70 else
71 return;
72
73 set_state(my_id, fullname, sym, &nospec);
74 }
75
76 static void match_call_info(struct expression *expr)
77 {
78 struct expression *arg;
79 int i = 0;
80
81 FOR_EACH_PTR(expr->args, arg) {
82 if (get_state_expr(my_id, arg) == &nospec)
83 sql_insert_caller_info(expr, NOSPEC, i, "$", "");
84 i++;
85 } END_FOR_EACH_PTR(arg);
86 }
87
88 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
89 {
90 struct range_list *rl;
91
92 if (!get_user_rl_var_sym(sm->name, sm->sym, &rl))
93 return;
94 sql_insert_caller_info(call, NOSPEC, param, printed_name, "");
95 }
96
97 static void returned_struct_members(int return_id, char *return_ranges, struct expression *expr)
98 {
99 struct symbol *returned_sym;
100 struct sm_state *sm;
101 const char *param_name;
102 struct range_list *rl;
103 int param;
104
105 returned_sym = expr_to_sym(expr);
106
107 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
108 param = get_param_num_from_sym(sm->sym);
109 if (param < 0) {
110 if (!returned_sym || returned_sym != sm->sym)
111 continue;
112 param = -1;
113 }
114
115 param_name = get_param_name(sm);
116 if (!param_name)
117 continue;
118 if (param != -1 && strcmp(param_name, "$") == 0)
119 continue;
120
121 if (!get_user_rl_var_sym(sm->name, sm->sym, &rl))
122 continue;
123
124 sql_insert_return_states(return_id, return_ranges, NOSPEC, param, param_name, "");
125 } END_FOR_EACH_SM(sm);
126
127 if (is_nospec(expr) && get_user_rl(expr, &rl))
128 sql_insert_return_states(return_id, return_ranges, NOSPEC, -1, "$", "");
129
130 if (get_state(barrier_id, "barrier", NULL) == &nospec)
131 sql_insert_return_states(return_id, return_ranges, NOSPEC_WB, -1, "", "");
132 }
133
134 static int is_return_statement(void)
135 {
136 if (__cur_stmt && __cur_stmt->type == STMT_RETURN)
137 return 1;
138 return 0;
139 }
140
141 static void db_returns_nospec(struct expression *expr, int param, char *key, char *value)
142 {
143 struct expression *call;
144 struct expression *arg;
145 char *name;
146 struct symbol *sym;
147
148 call = expr;
149 while (call->type == EXPR_ASSIGNMENT)
150 call = strip_expr(call->right);
151 if (call->type != EXPR_CALL)
152 return;
153
154 if (param == -1 && expr->type == EXPR_ASSIGNMENT) {
155 name = get_variable_from_key(expr->left, key, &sym);
156 } else if (param == -1 && is_return_statement()) {
157 in_nospec_stmt = true;
158 return;
159 } else {
160 arg = get_argument_from_call_expr(call->args, param);
161 if (!arg)
162 return;
163 name = get_variable_from_key(arg, key, &sym);
164 }
165 if (!name || !sym)
166 goto free;
167
168 set_state(my_id, name, sym, &nospec);
169 free:
170 free_string(name);
171 }
172
173 static int is_nospec_asm(struct statement *stmt)
174 {
175 char *macro;
176
177 if (!stmt || stmt->type != STMT_ASM)
178 return 0;
179 macro = get_macro_name(stmt->asm_string->pos);
180 if (!macro || strcmp(macro, "CALL_NOSPEC") != 0)
181 return 0;
182 return 1;
183 }
184
185 static void match_asm(struct statement *stmt)
186 {
187 if (is_nospec_asm(stmt))
188 in_nospec_stmt = true;
189 }
190
191 static void match_after_nospec_asm(struct statement *stmt)
192 {
193 in_nospec_stmt = false;
194 }
195
196 static void mark_user_data_as_nospec(void)
197 {
198 struct stree *stree;
199 struct symbol *type;
200 struct sm_state *sm;
201
202 stree = get_user_stree();
203 FOR_EACH_SM(stree, sm) {
204 if (is_whole_rl(estate_rl(sm->state)))
205 continue;
206 type = estate_type(sm->state);
207 if (!type || type->type != SYM_BASETYPE)
208 continue;
209 if (!is_capped_var_sym(sm->name, sm->sym))
210 continue;
211 set_state(my_id, sm->name, sm->sym, &nospec);
212 } END_FOR_EACH_SM(sm);
213 free_stree(&stree);
214 }
215
216 static void match_barrier(struct statement *stmt)
217 {
218 char *macro;
219
220 macro = get_macro_name(stmt->pos);
221 if (!macro)
222 return;
223 if (strcmp(macro, "rmb") != 0 &&
224 strcmp(macro, "smp_rmb") != 0 &&
225 strcmp(macro, "barrier_nospec") != 0)
226 return;
227
228 set_state(barrier_id, "barrier", NULL, &nospec);
229 mark_user_data_as_nospec();
230 }
231
232 static void db_returns_barrier(struct expression *expr, int param, char *key, char *value)
233 {
234 mark_user_data_as_nospec();
235 }
236
237 void check_nospec(int id)
238 {
239 my_id = id;
240
241 add_hook(&nospec_assign, ASSIGNMENT_HOOK);
242
243 select_caller_info_hook(set_param_nospec, NOSPEC);
244 add_unmatched_state_hook(my_id, &unmatched_state);
245
246 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
247 add_member_info_callback(my_id, struct_member_callback);
248 add_split_return_callback(&returned_struct_members);
249 select_return_states_hook(NOSPEC, &db_returns_nospec);
250 select_return_states_hook(NOSPEC_WB, &db_returns_barrier);
251
252 add_hook(&match_asm, ASM_HOOK);
253 add_hook(&match_after_nospec_asm, STMT_HOOK_AFTER);
254 }
255
256 void check_nospec_barrier(int id)
257 {
258 barrier_id = id;
259
260 add_hook(&match_barrier, ASM_HOOK);
261 }