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 void_fn_list *hooks;
  23 static int my_id;
  24
  25 STATE(sleep);
  26
  27 #define __GFP_ATOMIC 0x200u
  28 #define ___GFP_DIRECT_RECLAIM 0x400u
  29
  30 unsigned long GFP_DIRECT_RECLAIM(void)
  31 {
  32         static unsigned long saved_flags = -1;
  33         struct symbol *macro_sym;
  34
  35         if (saved_flags != -1)
  36                 return saved_flags;
  37
  38         macro_sym = lookup_macro_symbol("___GFP_DIRECT_RECLAIM");
  39         if (!macro_sym || !macro_sym->expansion)
  40                 return ___GFP_DIRECT_RECLAIM;
  41         if (token_type(macro_sym->expansion) != TOKEN_NUMBER)
  42                 return ___GFP_DIRECT_RECLAIM;
  43
  44         saved_flags = strtoul(macro_sym->expansion->number, NULL, 0);
  45         return saved_flags;
  46 }
  47
  48 unsigned long GFP_ATOMIC(void)
  49 {
  50         static unsigned long saved_flags = -1;
  51         struct symbol *macro_sym;
  52
  53         if (saved_flags != -1)
  54                 return saved_flags;
  55
  56         macro_sym = lookup_macro_symbol("___GFP_ATOMIC");
  57         if (!macro_sym || !macro_sym->expansion)
  58                 return __GFP_ATOMIC;
  59         if (token_type(macro_sym->expansion) != TOKEN_NUMBER)
  60                 return __GFP_ATOMIC;
  61
  62         saved_flags = strtoul(macro_sym->expansion->number, NULL, 0);
  63         return saved_flags;
  64 }
  65
  66 static void do_sleep(void)
  67 {
  68         void_fn *fn;
  69
  70         FOR_EACH_PTR(hooks, fn) {
  71                 fn();
  72         } END_FOR_EACH_PTR(fn);
  73
  74         set_state(my_id, "sleep", NULL, &sleep);
  75         clear_preempt_cnt();
  76 }
  77
  78 static void match_sleep(const char *fn, struct expression *expr, void *unused)
  79 {
  80         do_sleep();
  81 }
  82
  83 static void match_might_sleep_fn(const char *fn, struct expression *expr, void *unused)
  84 {
  85         struct range_list *rl;
  86         sval_t sval;
  87
  88         if (!get_implied_rl_from_call_str(expr, "$0", &rl))
  89                 return;
  90         if (!rl_to_sval(rl, &sval) || sval.value != 0)
  91                 return;
  92
  93         do_sleep();
  94 }
  95
  96 static void match_might_sleep_macro(struct statement *stmt)
  97 {
  98         const char *macro;
  99
 100         macro = get_macro_name(stmt->pos);
 101         if (!macro ||
 102             strcmp(macro, "might_sleep") != 0)
 103                 return;
 104
 105         do_sleep();
 106 }
 107
 108 static void select_sleep(struct expression *call, struct expression *arg, char *key, char *unused)
 109 {
 110         do_sleep();
 111 }
 112
 113 static void match_gfp_t(struct expression *expr)
 114 {
 115         struct expression *arg;
 116         char *name;
 117         sval_t sval;
 118         int param;
 119
 120         param = get_gfp_param(expr);
 121         if (param < 0)
 122                 return;
 123         arg = get_argument_from_call_expr(expr->args, param);
 124         if (!get_implied_value(arg, &sval))
 125                 return;
 126
 127         if (!(sval.value & GFP_DIRECT_RECLAIM()))
 128                 return;
 129         if (sval.uvalue & GFP_ATOMIC())
 130                 return;
 131
 132         name = expr_to_str(expr->fn);
 133         if (name &&
 134             (strncmp(name, "__xa_", 5) == 0 ||
 135              strncmp(name, "xa_", 3) == 0 ||
 136              strcmp(name, "ttm_bo_swapout") == 0)) {
 137                 free_string(name);
 138                 return;
 139         }
 140         free_string(name);
 141
 142         do_sleep();
 143 }
 144
 145 static void insert_sleep(void)
 146 {
 147         if (function_decrements_preempt())
 148                 return;
 149         if (get_state(my_id, "sleep", NULL) != &sleep)
 150                 return;
 151         sql_insert_return_implies(SLEEP, -1, "", "");
 152 }
 153
 154 void add_sleep_callback(void_fn *fn)
 155 {
 156         add_ptr_list(&hooks, fn);
 157 }
 158
 159 void check_sleep_info(int id)
 160 {
 161         my_id = id;
 162
 163         if (option_project != PROJ_KERNEL)
 164                 return;
 165
 166         add_function_hook("schedule", &match_sleep, NULL);
 167         add_function_hook("might_resched", &match_sleep, NULL);
 168         add_function_hook("__might_sleep", &match_might_sleep_fn, NULL);
 169         add_function_hook("___might_sleep", &match_might_sleep_fn, NULL);
 170         add_hook(&match_might_sleep_macro, STMT_HOOK);
 171
 172         add_hook(&match_gfp_t, FUNCTION_CALL_HOOK);
 173
 174         all_return_states_hook(&insert_sleep);
 175         select_return_implies_hook(SLEEP, &select_sleep);
 176 }