xref: /illumos-gate/usr/src/tools/smatch/src/check_nospec.c (revision 1f5207b7604fb44407eb4342aff613f7c4508508)
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 }
262