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         clear_irq_context();
  54 }
  55
  56 static void match_sleep(const char *fn, struct expression *expr, void *unused)
  57 {
  58         do_sleep(expr);
  59 }
  60
  61 static void match_might_sleep_fn(const char *fn, struct expression *expr, void *unused)
  62 {
  63         struct range_list *rl;
  64         sval_t sval;
  65
  66         if (!get_implied_rl_from_call_str(expr, "$0", &rl))
  67                 return;
  68         if (!rl_to_sval(rl, &sval) || sval.value != 0)
  69                 return;
  70
  71         do_sleep(expr);
  72 }
  73
  74 static void match_might_sleep_macro(struct statement *stmt)
  75 {
  76         const char *macro;
  77
  78         macro = get_macro_name(stmt->pos);
  79         if (!macro ||
  80             strcmp(macro, "might_sleep") != 0)
  81                 return;
  82
  83         do_sleep(NULL);
  84 }
  85
  86 static void select_sleep(struct expression *call, struct expression *arg, char *key, char *unused)
  87 {
  88         do_sleep(call);
  89 }
  90
  91 static bool is_strange_GFP_function(struct expression *expr)
  92 {
  93         char *name;
  94         bool ret = false;
  95
  96         if (!expr || expr->type != EXPR_CALL)
  97                 return false;
  98
  99         name = expr_to_str(expr->fn);
 100         if (!name)
 101                 return false;
 102
 103         if (strncmp(name, "__xa_", 5) == 0 ||
 104             strncmp(name, "xa_", 3) == 0 ||
 105             strcmp(name, "ttm_bo_swapout") == 0 ||
 106             strcmp(name, "mas_store_gfp") == 0)
 107                 ret = true;
 108
 109         free_string(name);
 110         return ret;
 111 }
 112
 113 static void match_gfp_t(struct expression *expr)
 114 {
 115         struct expression *arg;
 116         sval_t sval;
 117         int param;
 118
 119         param = get_gfp_param(expr);
 120         if (param < 0)
 121                 return;
 122         arg = get_argument_from_call_expr(expr->args, param);
 123         if (!get_implied_value(arg, &sval))
 124                 return;
 125
 126         if (!(sval.value & GFP_DIRECT_RECLAIM()))
 127                 return;
 128
 129         if (is_strange_GFP_function(expr))
 130                 return;
 131
 132         do_sleep(expr);
 133 }
 134
 135 static void insert_sleep(void)
 136 {
 137         if (get_state(my_id, "sleep", NULL) != &sleep)
 138                 return;
 139         sql_insert_return_implies(SLEEP, -2, "", "");
 140 }
 141
 142 void add_sleep_callback(expr_func *fn)
 143 {
 144         add_ptr_list(&hooks, fn);
 145 }
 146
 147 void check_sleep_info(int id)
 148 {
 149         my_id = id;
 150
 151         if (option_project != PROJ_KERNEL)
 152                 return;
 153
 154         add_function_hook("schedule", &match_sleep, NULL);
 155         add_function_hook("msleep", &match_sleep, NULL);
 156         add_function_hook("might_resched", &match_sleep, NULL);
 157         add_function_hook("vfree", &match_sleep, NULL);
 158         add_function_hook("__might_sleep", &match_might_sleep_fn, NULL);
 159         add_function_hook("___might_sleep", &match_might_sleep_fn, NULL);
 160         add_hook(&match_might_sleep_macro, STMT_HOOK);
 161
 162         add_hook(&match_gfp_t, FUNCTION_CALL_HOOK);
 163
 164         all_return_states_hook(&insert_sleep);
 165         select_return_implies_hook_early(SLEEP, &select_sleep);
 166 }