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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149// SPDX-License-Identifier: GPL-2.0-only#include <linux/limits.h>#include <linux/module.h>
/* validate @native and @pcp counter values match @expected */#define CHECK(native, pcp, expected) \ do { \ WARN((native) != (expected), \ "raw %ld (0x%lx) != expected %lld (0x%llx)", \ (native), (native), \ (long long)(expected), (long long)(expected)); \ WARN(__this_cpu_read(pcp) != (expected), \ "pcp %ld (0x%lx) != expected %lld (0x%llx)", \ __this_cpu_read(pcp), __this_cpu_read(pcp), \ (long long)(expected), (long long)(expected)); \ } while (0)
static DEFINE_PER_CPU(long, long_counter);static DEFINE_PER_CPU(unsigned long, ulong_counter);
static int __init percpu_test_init(void){ /* * volatile prevents compiler from optimizing it uses, otherwise the * +ul_one/-ul_one below would replace with inc/dec instructions. */ volatile unsigned int ui_one = 1; unsigned long long ull = 0; unsigned long ul = 0; long l = 0;
pr_info("percpu test start\n");
preempt_disable();
l += -1; __this_cpu_add(long_counter, -1); CHECK(l, long_counter, -1);
l += 1; __this_cpu_add(long_counter, 1); CHECK(l, long_counter, 0);
ul = 0; __this_cpu_write(ulong_counter, 0);
ul += 1UL; __this_cpu_add(ulong_counter, 1UL); CHECK(ul, ulong_counter, 1);
ul += -1UL; __this_cpu_add(ulong_counter, -1UL); CHECK(ul, ulong_counter, 0);
ul += -(unsigned long)1; __this_cpu_add(ulong_counter, -(unsigned long)1); CHECK(ul, ulong_counter, -1);
ul = 0; __this_cpu_write(ulong_counter, 0);
ul -= 1; __this_cpu_dec(ulong_counter); CHECK(ul, ulong_counter, -1); CHECK(ul, ulong_counter, ULONG_MAX);
l += -ui_one; __this_cpu_add(long_counter, -ui_one); CHECK(l, long_counter, 0xffffffff);
l += ui_one; __this_cpu_add(long_counter, ui_one); CHECK(l, long_counter, (long)0x100000000LL);
l = 0; __this_cpu_write(long_counter, 0);
l -= ui_one; __this_cpu_sub(long_counter, ui_one); CHECK(l, long_counter, -1);
l = 0; __this_cpu_write(long_counter, 0);
l += ui_one; __this_cpu_add(long_counter, ui_one); CHECK(l, long_counter, 1);
l += -ui_one; __this_cpu_add(long_counter, -ui_one); CHECK(l, long_counter, (long)0x100000000LL);
l = 0; __this_cpu_write(long_counter, 0);
l -= ui_one; this_cpu_sub(long_counter, ui_one); CHECK(l, long_counter, -1); CHECK(l, long_counter, ULONG_MAX);
ul = 0; __this_cpu_write(ulong_counter, 0);
ul += ui_one; __this_cpu_add(ulong_counter, ui_one); CHECK(ul, ulong_counter, 1);
ul = 0; __this_cpu_write(ulong_counter, 0);
ul -= ui_one; __this_cpu_sub(ulong_counter, ui_one); CHECK(ul, ulong_counter, -1); CHECK(ul, ulong_counter, ULONG_MAX);
ul = ull = 0; __this_cpu_write(ulong_counter, 0);
ul = ull += UINT_MAX; __this_cpu_add(ulong_counter, ull); CHECK(ul, ulong_counter, UINT_MAX);
ul = 3; __this_cpu_write(ulong_counter, 3);
ul = this_cpu_sub_return(ulong_counter, ui_one); CHECK(ul, ulong_counter, 2);
ul = __this_cpu_sub_return(ulong_counter, ui_one); CHECK(ul, ulong_counter, 1);
preempt_enable();
pr_info("percpu test done\n"); return -EAGAIN; /* Fail will directly unload the module */}
static void __exit percpu_test_exit(void){}
module_init(percpu_test_init)module_exit(percpu_test_exit)
MODULE_LICENSE("GPL");MODULE_AUTHOR("Greg Thelen");MODULE_DESCRIPTION("percpu operations test");