lib/test_bitops.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2020 Intel Corporation
   4  */
   5
   6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   7
   8 #include <linux/init.h>
   9 #include <linux/module.h>
  10 #include <linux/printk.h>
  11
  12 /* a tiny module only meant to test
  13  *
  14  *   set/clear_bit
  15  *   get_count_order/long
  16  */
  17
  18 /* use an enum because thats the most common BITMAP usage */
  19 enum bitops_fun {
  20         BITOPS_4 = 4,
  21         BITOPS_7 = 7,
  22         BITOPS_11 = 11,
  23         BITOPS_31 = 31,
  24         BITOPS_88 = 88,
  25         BITOPS_LAST = 255,
  26         BITOPS_LENGTH = 256
  27 };
  28
  29 static DECLARE_BITMAP(g_bitmap, BITOPS_LENGTH);
  30
  31 static unsigned int order_comb[][2] = {
  32         {0x00000003,  2},
  33         {0x00000004,  2},
  34         {0x00001fff, 13},
  35         {0x00002000, 13},
  36         {0x50000000, 31},
  37         {0x80000000, 31},
  38         {0x80003000, 32},
  39 };
  40
  41 #ifdef CONFIG_64BIT
  42 static unsigned long order_comb_long[][2] = {
  43         {0x0000000300000000, 34},
  44         {0x0000000400000000, 34},
  45         {0x00001fff00000000, 45},
  46         {0x0000200000000000, 45},
  47         {0x5000000000000000, 63},
  48         {0x8000000000000000, 63},
  49         {0x8000300000000000, 64},
  50 };
  51 #endif
  52
  53 static int __init test_bitops_startup(void)
  54 {
  55         int i;
  56
  57         pr_warn("Loaded test module\n");
  58         set_bit(BITOPS_4, g_bitmap);
  59         set_bit(BITOPS_7, g_bitmap);
  60         set_bit(BITOPS_11, g_bitmap);
  61         set_bit(BITOPS_31, g_bitmap);
  62         set_bit(BITOPS_88, g_bitmap);
  63
  64         for (i = 0; i < ARRAY_SIZE(order_comb); i++) {
  65                 if (order_comb[i][1] != get_count_order(order_comb[i][0]))
  66                         pr_warn("get_count_order wrong for %x\n",
  67                                        order_comb[i][0]);
  68         }
  69
  70         for (i = 0; i < ARRAY_SIZE(order_comb); i++) {
  71                 if (order_comb[i][1] != get_count_order_long(order_comb[i][0]))
  72                         pr_warn("get_count_order_long wrong for %x\n",
  73                                        order_comb[i][0]);
  74         }
  75
  76 #ifdef CONFIG_64BIT
  77         for (i = 0; i < ARRAY_SIZE(order_comb_long); i++) {
  78                 if (order_comb_long[i][1] !=
  79                                get_count_order_long(order_comb_long[i][0]))
  80                         pr_warn("get_count_order_long wrong for %lx\n",
  81                                        order_comb_long[i][0]);
  82         }
  83 #endif
  84         return 0;
  85 }
  86
  87 static void __exit test_bitops_unstartup(void)
  88 {
  89         int bit_set;
  90
  91         clear_bit(BITOPS_4, g_bitmap);
  92         clear_bit(BITOPS_7, g_bitmap);
  93         clear_bit(BITOPS_11, g_bitmap);
  94         clear_bit(BITOPS_31, g_bitmap);
  95         clear_bit(BITOPS_88, g_bitmap);
  96
  97         bit_set = find_first_bit(g_bitmap, BITOPS_LAST);
  98         if (bit_set != BITOPS_LAST)
  99                 pr_err("ERROR: FOUND SET BIT %d\n", bit_set);
 100
 101         pr_warn("Unloaded test module\n");
 102 }
 103
 104 module_init(test_bitops_startup);
 105 module_exit(test_bitops_unstartup);
 106
 107 MODULE_AUTHOR("Jesse Brandeburg <jesse.brandeburg@intel.com>, Wei Yang <richard.weiyang@gmail.com>");
 108 MODULE_LICENSE("GPL");
 109 MODULE_DESCRIPTION("Bit testing module");