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/cleanup.h>
   9 #include <linux/init.h>
  10 #include <linux/module.h>
  11 #include <linux/printk.h>
  12 #include <linux/slab.h>
  13
  14 /* a tiny module only meant to test
  15  *
  16  *   set/clear_bit
  17  *   get_count_order/long
  18  */
  19
  20 /* use an enum because that's the most common BITMAP usage */
  21 enum bitops_fun {
  22         BITOPS_4 = 4,
  23         BITOPS_7 = 7,
  24         BITOPS_11 = 11,
  25         BITOPS_31 = 31,
  26         BITOPS_88 = 88,
  27         BITOPS_LAST = 255,
  28         BITOPS_LENGTH = 256
  29 };
  30
  31 static DECLARE_BITMAP(g_bitmap, BITOPS_LENGTH);
  32
  33 static unsigned int order_comb[][2] = {
  34         {0x00000003,  2},
  35         {0x00000004,  2},
  36         {0x00001fff, 13},
  37         {0x00002000, 13},
  38         {0x50000000, 31},
  39         {0x80000000, 31},
  40         {0x80003000, 32},
  41 };
  42
  43 #ifdef CONFIG_64BIT
  44 static unsigned long order_comb_long[][2] = {
  45         {0x0000000300000000, 34},
  46         {0x0000000400000000, 34},
  47         {0x00001fff00000000, 45},
  48         {0x0000200000000000, 45},
  49         {0x5000000000000000, 63},
  50         {0x8000000000000000, 63},
  51         {0x8000300000000000, 64},
  52 };
  53 #endif
  54
  55 static int __init test_fns(void)
  56 {
  57         static volatile __always_used unsigned long tmp __initdata;
  58         unsigned long *buf __free(kfree) = NULL;
  59         unsigned int i, n;
  60         ktime_t time;
  61
  62         buf = kmalloc_array(10000, sizeof(unsigned long), GFP_KERNEL);
  63         if (!buf)
  64                 return -ENOMEM;
  65
  66         get_random_bytes(buf, 10000 * sizeof(unsigned long));
  67         time = ktime_get();
  68
  69         for (n = 0; n < BITS_PER_LONG; n++)
  70                 for (i = 0; i < 10000; i++)
  71                         tmp = fns(buf[i], n);
  72
  73         time = ktime_get() - time;
  74         pr_err("fns:  %18llu ns\n", time);
  75
  76         return 0;
  77 }
  78
  79 static int __init test_bitops_startup(void)
  80 {
  81         int i, bit_set;
  82
  83         pr_info("Starting bitops test\n");
  84         set_bit(BITOPS_4, g_bitmap);
  85         set_bit(BITOPS_7, g_bitmap);
  86         set_bit(BITOPS_11, g_bitmap);
  87         set_bit(BITOPS_31, g_bitmap);
  88         set_bit(BITOPS_88, g_bitmap);
  89
  90         for (i = 0; i < ARRAY_SIZE(order_comb); i++) {
  91                 if (order_comb[i][1] != get_count_order(order_comb[i][0]))
  92                         pr_warn("get_count_order wrong for %x\n",
  93                                        order_comb[i][0]);
  94         }
  95
  96         for (i = 0; i < ARRAY_SIZE(order_comb); i++) {
  97                 if (order_comb[i][1] != get_count_order_long(order_comb[i][0]))
  98                         pr_warn("get_count_order_long wrong for %x\n",
  99                                        order_comb[i][0]);
 100         }
 101
 102 #ifdef CONFIG_64BIT
 103         for (i = 0; i < ARRAY_SIZE(order_comb_long); i++) {
 104                 if (order_comb_long[i][1] !=
 105                                get_count_order_long(order_comb_long[i][0]))
 106                         pr_warn("get_count_order_long wrong for %lx\n",
 107                                        order_comb_long[i][0]);
 108         }
 109 #endif
 110
 111         barrier();
 112
 113         clear_bit(BITOPS_4, g_bitmap);
 114         clear_bit(BITOPS_7, g_bitmap);
 115         clear_bit(BITOPS_11, g_bitmap);
 116         clear_bit(BITOPS_31, g_bitmap);
 117         clear_bit(BITOPS_88, g_bitmap);
 118
 119         bit_set = find_first_bit(g_bitmap, BITOPS_LAST);
 120         if (bit_set != BITOPS_LAST)
 121                 pr_err("ERROR: FOUND SET BIT %d\n", bit_set);
 122
 123         test_fns();
 124
 125         pr_info("Completed bitops test\n");
 126
 127         return 0;
 128 }
 129
 130 static void __exit test_bitops_unstartup(void)
 131 {
 132 }
 133
 134 module_init(test_bitops_startup);
 135 module_exit(test_bitops_unstartup);
 136
 137 MODULE_AUTHOR("Jesse Brandeburg <[email protected]>, Wei Yang <[email protected]>");
 138 MODULE_LICENSE("GPL");
 139 MODULE_DESCRIPTION("Bit testing module");