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 clear_state(struct sm_state *sm, struct expression *mod_expr)
  27 {
  28         set_state(my_id, sm->name, sm->sym, &undefined);
  29 }
  30
  31 static void match_platform_get_irq(struct expression *expr, const char *name, struct symbol *sym, void *data)
  32 {
  33         set_state(my_id, name, sym, &get_irq);
  34 }
  35
  36 static bool assigned_zero(struct expression *expr)
  37 {
  38         struct sm_state *sm, *tmp;
  39         struct expression *prev;
  40
  41         sm = get_assigned_sm(expr);
  42         if (!sm)
  43                 return false;
  44         FOR_EACH_PTR(sm->possible, tmp) {
  45                 prev = tmp->state->data;
  46                 if (expr_is_zero(prev))
  47                         return true;
  48         } END_FOR_EACH_PTR(tmp);
  49
  50         return false;
  51 }
  52
  53 static bool is_part_of_select(struct expression *expr)
  54 {
  55         struct expression *parent;
  56         sval_t sval;
  57
  58         /* Code like "return irq ?: -EINVAL;" is wrong but harmless */
  59
  60         parent = expr_get_parent_expr(expr);
  61         if (!parent)
  62                 return false;
  63         if (parent->type != EXPR_CONDITIONAL &&
  64             parent->type != EXPR_SELECT)
  65                 return false;
  66
  67         if (get_value(parent->cond_false, &sval) &&
  68             sval.value >= -4095 &&
  69             sval.value < 0)
  70                 return true;
  71
  72         return false;
  73 }
  74
  75 static void match_condition(struct expression *expr)
  76 {
  77         struct range_list *rl;
  78
  79         if (!expr_has_possible_state(my_id, expr, &get_irq))
  80                 return;
  81
  82         if (get_implied_rl(expr, &rl) && rl_min(rl).value == 0)
  83                 return;
  84
  85         if (assigned_zero(expr))
  86                 return;
  87
  88         if (is_part_of_select(expr))
  89                 return;
  90
  91         sm_msg("warn: platform_get_irq() does not return zero");
  92 }
  93
  94 void check_platform_get_irq_return(int id)
  95 {
  96         my_id = id;
  97
  98         add_function_param_key_hook_late("platform_get_irq", &match_platform_get_irq, -1, "$", NULL);
  99         add_function_param_key_hook_late("platform_get_irq_optional", &match_platform_get_irq, -1, "$", NULL);
 100         add_function_param_key_hook_late("platform_get_irq_byname", &match_platform_get_irq, -1, "$", NULL);
 101         add_function_param_key_hook_late("platform_get_irq_byname_optional", &match_platform_get_irq, -1, "$", NULL);
 102         add_modification_hook(my_id, &clear_state);
 103         add_hook(&match_condition, CONDITION_HOOK);
 104 }