check_platform_get_irq_return.c

   1 /*
   2  * Copyright (C) 2022 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_slist.h"
  20 #include "smatch_extra.h"
  21
  22 static int my_id;
  23
  24 STATE(get_irq);
  25
  26 static void match_platform_get_irq(struct expression *expr, const char *name, struct symbol *sym, void *data)
  27 {
  28         set_state(my_id, name, sym, &get_irq);
  29 }
  30
  31 static bool assigned_zero(struct expression *expr)
  32 {
  33         struct sm_state *sm, *tmp;
  34         struct expression *prev;
  35
  36         sm = get_assigned_sm(expr);
  37         if (!sm)
  38                 return false;
  39         FOR_EACH_PTR(sm->possible, tmp) {
  40                 prev = tmp->state->data;
  41                 if (expr_is_zero(prev))
  42                         return true;
  43         } END_FOR_EACH_PTR(tmp);
  44
  45         return false;
  46 }
  47
  48 static bool is_part_of_select(struct expression *expr)
  49 {
  50         struct expression *parent;
  51         sval_t sval;
  52
  53         /* Code like "return irq ?: -EINVAL;" is wrong but harmless */
  54
  55         parent = expr_get_parent_expr(expr);
  56         if (!parent)
  57                 return false;
  58         if (parent->type != EXPR_CONDITIONAL &&
  59             parent->type != EXPR_SELECT)
  60                 return false;
  61
  62         if (get_value(parent->cond_false, &sval) &&
  63             sval.value >= -4095 &&
  64             sval.value < 0)
  65                 return true;
  66
  67         return false;
  68 }
  69
  70 static void match_condition(struct expression *expr)
  71 {
  72         struct range_list *rl;
  73
  74         if (!expr_has_possible_state(my_id, expr, &get_irq))
  75                 return;
  76
  77         if (get_implied_rl(expr, &rl) && rl_min(rl).value == 0)
  78                 return;
  79
  80         if (assigned_zero(expr))
  81                 return;
  82
  83         if (is_part_of_select(expr))
  84                 return;
  85
  86         sm_msg("warn: platform_get_irq() does not return zero");
  87 }
  88
  89 void check_platform_get_irq_return(int id)
  90 {
  91         my_id = id;
  92
  93         add_function_param_key_hook_late("platform_get_irq", &match_platform_get_irq, -1, "$", NULL);
  94         add_function_param_key_hook_late("platform_get_irq_optional", &match_platform_get_irq, -1, "$", NULL);
  95         add_function_param_key_hook_late("platform_get_irq_byname", &match_platform_get_irq, -1, "$", NULL);
  96         add_function_param_key_hook_late("platform_get_irq_byname_optional", &match_platform_get_irq, -1, "$", NULL);
  97         add_modification_hook(my_id, &set_undefined);
  98         add_hook(&match_condition, CONDITION_HOOK);
  99 }