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test_bitops.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2020 Intel Corporation
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/cleanup.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/slab.h>
/* a tiny module only meant to test
*
* set/clear_bit
* get_count_order/long
*/
/* use an enum because that's the most common BITMAP usage */
enum bitops_fun {
BITOPS_4 = 4,
BITOPS_7 = 7,
BITOPS_11 = 11,
BITOPS_31 = 31,
BITOPS_88 = 88,
BITOPS_LAST = 255,
BITOPS_LENGTH = 256
};
static DECLARE_BITMAP(g_bitmap, BITOPS_LENGTH);
static unsigned int order_comb[][2] = {
{0x00000003, 2},
{0x00000004, 2},
{0x00001fff, 13},
{0x00002000, 13},
{0x50000000, 31},
{0x80000000, 31},
{0x80003000, 32},
};
#ifdef CONFIG_64BIT
static unsigned long order_comb_long[][2] = {
{0x0000000300000000, 34},
{0x0000000400000000, 34},
{0x00001fff00000000, 45},
{0x0000200000000000, 45},
{0x5000000000000000, 63},
{0x8000000000000000, 63},
{0x8000300000000000, 64},
};
#endif
static int __init test_fns(void)
{
static volatile __always_used unsigned long tmp __initdata;
unsigned long *buf __free(kfree) = NULL;
unsigned int i, n;
ktime_t time;
buf = kmalloc_array(10000, sizeof(unsigned long), GFP_KERNEL);
if (!buf)
return -ENOMEM;
get_random_bytes(buf, 10000 * sizeof(unsigned long));
time = ktime_get();
for (n = 0; n < BITS_PER_LONG; n++)
for (i = 0; i < 10000; i++)
tmp = fns(buf[i], n);
time = ktime_get() - time;
pr_err("fns: %18llu ns\n", time);
return 0;
}
static int __init test_bitops_startup(void)
{
int i, bit_set;
pr_info("Starting bitops test\n");
set_bit(BITOPS_4, g_bitmap);
set_bit(BITOPS_7, g_bitmap);
set_bit(BITOPS_11, g_bitmap);
set_bit(BITOPS_31, g_bitmap);
set_bit(BITOPS_88, g_bitmap);
for (i = 0; i < ARRAY_SIZE(order_comb); i++) {
if (order_comb[i][1] != get_count_order(order_comb[i][0]))
pr_warn("get_count_order wrong for %x\n",
order_comb[i][0]);
}
for (i = 0; i < ARRAY_SIZE(order_comb); i++) {
if (order_comb[i][1] != get_count_order_long(order_comb[i][0]))
pr_warn("get_count_order_long wrong for %x\n",
order_comb[i][0]);
}
#ifdef CONFIG_64BIT
for (i = 0; i < ARRAY_SIZE(order_comb_long); i++) {
if (order_comb_long[i][1] !=
get_count_order_long(order_comb_long[i][0]))
pr_warn("get_count_order_long wrong for %lx\n",
order_comb_long[i][0]);
}
#endif
barrier();
clear_bit(BITOPS_4, g_bitmap);
clear_bit(BITOPS_7, g_bitmap);
clear_bit(BITOPS_11, g_bitmap);
clear_bit(BITOPS_31, g_bitmap);
clear_bit(BITOPS_88, g_bitmap);
bit_set = find_first_bit(g_bitmap, BITOPS_LAST);
if (bit_set != BITOPS_LAST)
pr_err("ERROR: FOUND SET BIT %d\n", bit_set);
test_fns();
pr_info("Completed bitops test\n");
return 0;
}
static void __exit test_bitops_unstartup(void)
{
}
module_init(test_bitops_startup);
module_exit(test_bitops_unstartup);
MODULE_AUTHOR("Jesse Brandeburg <[email protected]>, Wei Yang <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Bit testing module");