check_kvmalloc_array_zero.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 /*
  19  * This check complains when we have a function used with __GFP_ZERO flag and
  20  * we can use a less verbose alternative.
  21  *
  22  * Example: kmalloc_array + __GPF_ZERO = kcalloc
  23  */
  24
  25 #include "smatch.h"
  26
  27 static int my_id;
  28
  29 struct match_alloc_struct {
  30         const char *function;
  31         const char *alternative;
  32         int flag_pos;
  33 };
  34
  35 struct match_alloc_struct match_alloc_functions[] = {
  36         { "kmalloc", "kzalloc", 1 },
  37         { "kmalloc_node", "kzalloc_node", 1 },
  38
  39         { "kmalloc_array", "kcalloc", 2 },
  40         { "kmalloc_array_node", "kcalloc_node", 2 },
  41
  42         { "kvmalloc", "kvzalloc", 1 },
  43         { "kvmalloc_node", "kvzalloc_node", 1 },
  44
  45         { "kvmalloc_array", "kvcalloc", 2 },
  46
  47         { "kmem_cache_alloc", "kmem_cache_zalloc", 1 },
  48         { NULL, NULL, 0 }
  49 };
  50
  51 static void match_alloc(const char *fn, struct expression *expr, void *_arg)
  52 {
  53         struct match_alloc_struct *entry = match_alloc_functions;
  54         unsigned long gfp;
  55         int arg_nr = PTR_INT(_arg);
  56         struct expression *arg_expr;
  57         sval_t sval;
  58
  59         arg_expr = get_argument_from_call_expr(expr->args, arg_nr);
  60         if (!get_value(arg_expr, &sval))
  61                 return;
  62
  63         if (!macro_to_ul("__GFP_ZERO", &gfp))
  64                 return;
  65
  66         if (sval.uvalue & gfp) {
  67                 while (entry->function) {
  68                         if (strcmp(fn, entry->function) == 0) {
  69                                 sm_warning("Please consider using %s instead of %s",
  70                                            entry->alternative, entry->function);
  71                                 break;
  72                         }
  73                         entry++;
  74                 }
  75         }
  76 }
  77
  78 void check_kvmalloc_array_zero(int id)
  79 {
  80         struct match_alloc_struct *entry = match_alloc_functions;
  81
  82         if (option_project != PROJ_KERNEL)
  83                 return;
  84
  85         my_id = id;
  86
  87         while (entry->function) {
  88                 add_function_hook(entry->function, &match_alloc, INT_PTR(entry->flag_pos));
  89                 entry++;
  90         }
  91 }