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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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c348c16305
Test some bit clears/sets to make sure assembly doesn't change, and that the set_bit and clear_bit functions work and don't cause sparse warnings. Instruct Kbuild to build this file with extra warning level -Wextra, to catch new issues, and also doesn't hurt to build with C=1. This was used to test changes to arch/x86/include/asm/bitops.h. In particular, sparse (C=1) was very concerned when the last bit before a natural boundary, like 7, or 31, was being tested, as this causes sign extension (0xffffff7f) for instance when clearing bit 7. Recommended usage: make defconfig scripts/config -m CONFIG_TEST_BITOPS make modules_prepare make C=1 W=1 lib/test_bitops.ko objdump -S -d lib/test_bitops.ko insmod lib/test_bitops.ko rmmod lib/test_bitops.ko <check dmesg>, there should be no compiler/sparse warnings and no error messages in log. Link: http://lkml.kernel.org/r/20200310221747.2848474-2-jesse.brandeburg@intel.com Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> CcL Ingo Molnar <mingo@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
61 lines
1.3 KiB
C
61 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2020 Intel Corporation
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/printk.h>
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/* a tiny module only meant to test set/clear_bit */
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/* use an enum because thats the most common BITMAP usage */
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enum bitops_fun {
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BITOPS_4 = 4,
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BITOPS_7 = 7,
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BITOPS_11 = 11,
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BITOPS_31 = 31,
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BITOPS_88 = 88,
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BITOPS_LAST = 255,
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BITOPS_LENGTH = 256
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};
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static DECLARE_BITMAP(g_bitmap, BITOPS_LENGTH);
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static int __init test_bitops_startup(void)
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{
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pr_warn("Loaded test module\n");
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set_bit(BITOPS_4, g_bitmap);
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set_bit(BITOPS_7, g_bitmap);
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set_bit(BITOPS_11, g_bitmap);
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set_bit(BITOPS_31, g_bitmap);
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set_bit(BITOPS_88, g_bitmap);
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return 0;
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}
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static void __exit test_bitops_unstartup(void)
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{
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int bit_set;
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clear_bit(BITOPS_4, g_bitmap);
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clear_bit(BITOPS_7, g_bitmap);
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clear_bit(BITOPS_11, g_bitmap);
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clear_bit(BITOPS_31, g_bitmap);
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clear_bit(BITOPS_88, g_bitmap);
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bit_set = find_first_bit(g_bitmap, BITOPS_LAST);
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if (bit_set != BITOPS_LAST)
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pr_err("ERROR: FOUND SET BIT %d\n", bit_set);
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pr_warn("Unloaded test module\n");
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}
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module_init(test_bitops_startup);
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module_exit(test_bitops_unstartup);
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MODULE_AUTHOR("Jesse Brandeburg <jesse.brandeburg@intel.com>");
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Bit testing module");
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