check_sleep_info.c

   1 /*
   2  * Copyright (C) 2021 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 #include "smatch_slist.h"
  21
  22 static struct expr_fn_list *hooks;
  23
  24 static int my_id;
  25
  26 STATE(sleep);
  27
  28 unsigned long GFP_DIRECT_RECLAIM(void)
  29 {
  30         static unsigned long saved_flags = -1;
  31         struct symbol *macro_sym;
  32
  33         if (saved_flags != -1)
  34                 return saved_flags;
  35
  36         macro_sym = lookup_macro_symbol("___GFP_DIRECT_RECLAIM");
  37         if (!macro_sym || !macro_sym->expansion)
  38                 return 0;
  39         if (token_type(macro_sym->expansion) != TOKEN_NUMBER)
  40                 return 0;
  41
  42         saved_flags = strtoul(macro_sym->expansion->number, NULL, 0);
  43         return saved_flags;
  44 }
  45
  46 static void do_sleep(struct expression *expr)
  47 {
  48         call_expr_fns(hooks, expr);
  49
  50         if (!function_decrements_preempt())
  51                 set_state(my_id, "sleep", NULL, &sleep);
  52         clear_preempt_cnt();
  53 }
  54
  55 static void match_sleep(const char *fn, struct expression *expr, void *unused)
  56 {
  57         do_sleep(expr);
  58 }
  59
  60 static void match_might_sleep_fn(const char *fn, struct expression *expr, void *unused)
  61 {
  62         struct range_list *rl;
  63         sval_t sval;
  64
  65         if (!get_implied_rl_from_call_str(expr, "$0", &rl))
  66                 return;
  67         if (!rl_to_sval(rl, &sval) || sval.value != 0)
  68                 return;
  69
  70         do_sleep(expr);
  71 }
  72
  73 static void match_might_sleep_macro(struct statement *stmt)
  74 {
  75         const char *macro;
  76
  77         macro = get_macro_name(stmt->pos);
  78         if (!macro ||
  79             strcmp(macro, "might_sleep") != 0)
  80                 return;
  81
  82         do_sleep(NULL);
  83 }
  84
  85 static void select_sleep(struct expression *call, struct expression *arg, char *key, char *unused)
  86 {
  87         do_sleep(call);
  88 }
  89
  90 static bool is_strange_GFP_function(struct expression *expr)
  91 {
  92         char *name;
  93         bool ret = false;
  94
  95         if (!expr || expr->type != EXPR_CALL)
  96                 return false;
  97
  98         name = expr_to_str(expr->fn);
  99         if (!name)
 100                 return false;
 101
 102         if (strncmp(name, "__xa_", 5) == 0 ||
 103             strncmp(name, "xa_", 3) == 0 ||
 104             strcmp(name, "ttm_bo_swapout") == 0 ||
 105             strcmp(name, "mas_store_gfp") == 0)
 106                 ret = true;
 107
 108         free_string(name);
 109         return ret;
 110 }
 111
 112 static void match_gfp_t(struct expression *expr)
 113 {
 114         struct expression *arg;
 115         sval_t sval;
 116         int param;
 117
 118         param = get_gfp_param(expr);
 119         if (param < 0)
 120                 return;
 121         arg = get_argument_from_call_expr(expr->args, param);
 122         if (!get_implied_value(arg, &sval))
 123                 return;
 124
 125         if (!(sval.value & GFP_DIRECT_RECLAIM()))
 126                 return;
 127
 128         if (is_strange_GFP_function(expr))
 129                 return;
 130
 131         do_sleep(expr);
 132 }
 133
 134 static void insert_sleep(void)
 135 {
 136         if (get_state(my_id, "sleep", NULL) != &sleep)
 137                 return;
 138         sql_insert_return_implies(SLEEP, -2, "", "");
 139 }
 140
 141 void add_sleep_callback(expr_func *fn)
 142 {
 143         add_ptr_list(&hooks, fn);
 144 }
 145
 146 void check_sleep_info(int id)
 147 {
 148         my_id = id;
 149
 150         if (option_project != PROJ_KERNEL)
 151                 return;
 152
 153         add_function_hook("schedule", &match_sleep, NULL);
 154         add_function_hook("msleep", &match_sleep, NULL);
 155         add_function_hook("might_resched", &match_sleep, NULL);
 156         add_function_hook("vfree", &match_sleep, NULL);
 157         add_function_hook("__might_sleep", &match_might_sleep_fn, NULL);
 158         add_function_hook("___might_sleep", &match_might_sleep_fn, NULL);
 159         add_hook(&match_might_sleep_macro, STMT_HOOK);
 160
 161         add_hook(&match_gfp_t, FUNCTION_CALL_HOOK);
 162
 163         all_return_states_hook(&insert_sleep);
 164         select_return_implies_hook_early(SLEEP, &select_sleep);
 165 }