1 /*
2 * Copyright (C) 2014 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 "smatch.h"
19 #include "smatch_extra.h"
20
21 static int my_id;
22
23 STATE(readl);
24 STATE(readl_ff);
25 STATE(readl_00);
26
27 DECLARE_PTR_LIST(state_stack, struct smatch_state);
28 struct state_stack *state_at_start;
29
30 static int readl_has_been_called;
31 static int returned;
32
is_readl_call(struct expression * expr)33 static int is_readl_call(struct expression *expr)
34 {
35 struct symbol *sym;
36
37 expr = strip_expr(expr);
38 if (expr->type != EXPR_CALL)
39 return 0;
40 if (expr->fn->type != EXPR_SYMBOL)
41 return 0;
42 sym = expr->fn->symbol;
43 if (!sym || !sym->ident)
44 return 0;
45 if (strcmp(sym->ident->name, "readl") != 0)
46 return 0;
47 return 1;
48 }
49
is_readl(struct expression * expr)50 static int is_readl(struct expression *expr)
51 {
52 if (is_readl_call(expr))
53 return 1;
54 if (get_state_expr(my_id, expr) == &readl)
55 return 1;
56 return 0;
57 }
58
match_assign(struct expression * expr)59 static void match_assign(struct expression *expr)
60 {
61 if (is_readl(expr->right))
62 set_state_expr(my_id, expr->left, &readl);
63 else if (get_state_expr(my_id, expr->left))
64 set_state_expr(my_id, expr->left, &undefined);
65 }
66
condition_depends_on_readl(struct expression * expr)67 static int condition_depends_on_readl(struct expression *expr)
68 {
69 if (expr->type == EXPR_BINOP) {
70 if (condition_depends_on_readl(expr->left))
71 return 1;
72 if (condition_depends_on_readl(expr->right))
73 return 1;
74 return 0;
75 }
76 if (is_readl(expr))
77 return 1;
78 return 0;
79 }
80
check_condition(struct expression * expr)81 static void check_condition(struct expression *expr)
82 {
83 if (expr->op != '&')
84 return;
85 if (!condition_depends_on_readl(expr))
86 return;
87 readl_has_been_called = 1;
88 set_true_false_states(my_id, "depends on", NULL, &readl_ff, &readl_00);
89 }
90
match_return(struct expression * expr)91 static void match_return(struct expression *expr)
92 {
93
94 if (__inline_fn)
95 return;
96 returned = 1;
97 #if 0
98 struct smatch_state *tmp;
99
100 if (!readl_has_been_called)
101 return;
102
103 FOR_EACH_PTR(state_at_start, tmp) {
104 REPLACE_CURRENT_PTR(tmp, NULL);
105 }
106 #endif
107 }
108
push_state_at_start(struct smatch_state * state)109 static void push_state_at_start(struct smatch_state *state)
110 {
111 add_ptr_list(&state_at_start, state);
112 }
113
pop_state_at_start(void)114 static struct smatch_state *pop_state_at_start(void)
115 {
116 struct smatch_state *state;
117
118 state = last_ptr_list((struct ptr_list *)state_at_start);
119 delete_ptr_list_last((struct ptr_list **)&state_at_start);
120 return state;
121 }
122
before_loop(struct statement * stmt)123 static void before_loop(struct statement *stmt)
124 {
125 struct smatch_state *state;
126
127 if (!stmt || stmt->type != STMT_ITERATOR)
128 return;
129 if (ptr_list_empty((struct ptr_list *)state_at_start))
130 returned = 0;
131 state = get_state(my_id, "depends on", NULL);
132 push_state_at_start(state);
133 }
134
after_loop(struct statement * stmt)135 static void after_loop(struct statement *stmt)
136 {
137 struct smatch_state *old_state;
138
139 if (!stmt || stmt->type != STMT_ITERATOR)
140 return;
141 old_state = pop_state_at_start();
142 if (old_state == &readl_00)
143 return;
144 if (returned)
145 return;
146 if (get_state(my_id, "depends on", NULL) != &readl_00)
147 return;
148 sm_warning("this loop depends on readl() succeeding");
149 }
150
check_readl_infinite_loops(int id)151 void check_readl_infinite_loops(int id)
152 {
153 if (option_project != PROJ_KERNEL)
154 return;
155
156 my_id = id;
157
158 add_hook(match_assign, ASSIGNMENT_HOOK);
159 add_hook(check_condition, CONDITION_HOOK);
160
161 add_hook(&match_return, RETURN_HOOK);
162
163 add_hook(before_loop, STMT_HOOK);
164 add_hook(after_loop, STMT_HOOK_AFTER);
165 }
166