The 'max' parameter of ida_alloc_max() and ida_alloc_range() is not interpreted as it was in the deprecated ida_simple_get(). The 'max' value in the new functions is inclusive but it was exclusive before. So, in older code, this parameter was often a power of 2, such as 1 << 16, so that the maximum possible value was 0xffff. Now a power of 2 value is spurious. Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx> --- Most of the code is stolen from smatch_power_of_two.c --- check_ida_alloc.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++ check_list.h | 1 + 2 files changed, 84 insertions(+) create mode 100644 check_ida_alloc.c diff --git a/check_ida_alloc.c b/check_ida_alloc.c new file mode 100644 index 000000000000..7f1f7463d404 --- /dev/null +++ b/check_ida_alloc.c @@ -0,0 +1,83 @@ +/* + * Copyright (C) 2022 Christophe Jaillet. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt + */ + +/* + * The 'max' parameter of ida_alloc_max() and ida_alloc_range() is not interpreted + * as it was in the deprecated ida_simple_get(). + * + * The 'max' value in the new functions is inclusive but it was exclusive before. + * So, in older code, this parameter was often a power of 2, such as 1 << 16, so + * that the maximum possible value was 0xffff. + * + * Now a power of 2 value is spurious. + */ +#include <fcntl.h> +#include <unistd.h> +#include "parse.h" +#include "smatch.h" + +static int my_id; + +static bool implied_power_of_two(struct expression *expr) +{ + sval_t sval; + + if (!get_implied_value(expr, &sval)) + return false; + if (!(sval.uvalue & (sval.uvalue - 1))) + return true; + return false; +} + +static bool is_power_of_two(struct expression *expr) +{ + expr = strip_expr(expr); + + if (expr->type == EXPR_BINOP && + expr->op == SPECIAL_LEFTSHIFT && + is_power_of_two(expr->left)) + return true; + + if (implied_power_of_two(expr)) + return true; + + return false; +} + +static void match_ida_alloc(const char *fn, struct expression *expr, void *_arg_nr) +{ + int arg_nr = PTR_INT(_arg_nr); + struct expression *arg_expr; + + arg_expr = get_argument_from_call_expr(expr->args, arg_nr); + arg_expr = strip_expr(arg_expr); + + if (is_power_of_two(arg_expr)) + sm_error("Calling %s() with a 'max' argument which is a power of 2. -1 missing?", + fn); +} + +void check_ida_alloc(int id) +{ + if (option_project != PROJ_KERNEL) + return; + + my_id = id; + + add_function_hook("ida_alloc_max", &match_ida_alloc, INT_PTR(1)); + add_function_hook("ida_alloc_range", &match_ida_alloc, INT_PTR(2)); +} diff --git a/check_list.h b/check_list.h index fc6bce42656a..3f8e35d34a8b 100644 --- a/check_list.h +++ b/check_list.h @@ -183,6 +183,7 @@ CK(check_trinity_generator) CK(register_param_bits_set) CK(register_param_bits_clear) CK(check_do_while_loop_limit) +CK(check_ida_alloc) /* <- your test goes here */ /* CK(register_template) */ -- 2.34.1
