| Thomas Gleixner | 09c434b | 2019-05-19 13:08:20 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-only |
| Greg Thelen | 623fd80 | 2013-11-12 15:08:34 -0800 | [diff] [blame] | 2 | #include <linux/module.h> |
| 3 | |
| 4 | /* validate @native and @pcp counter values match @expected */ |
| 5 | #define CHECK(native, pcp, expected) \ |
| 6 | do { \ |
| 7 | WARN((native) != (expected), \ |
| 8 | "raw %ld (0x%lx) != expected %lld (0x%llx)", \ |
| 9 | (native), (native), \ |
| 10 | (long long)(expected), (long long)(expected)); \ |
| 11 | WARN(__this_cpu_read(pcp) != (expected), \ |
| 12 | "pcp %ld (0x%lx) != expected %lld (0x%llx)", \ |
| 13 | __this_cpu_read(pcp), __this_cpu_read(pcp), \ |
| 14 | (long long)(expected), (long long)(expected)); \ |
| 15 | } while (0) |
| 16 | |
| 17 | static DEFINE_PER_CPU(long, long_counter); |
| 18 | static DEFINE_PER_CPU(unsigned long, ulong_counter); |
| 19 | |
| 20 | static int __init percpu_test_init(void) |
| 21 | { |
| 22 | /* |
| 23 | * volatile prevents compiler from optimizing it uses, otherwise the |
| 24 | * +ul_one/-ul_one below would replace with inc/dec instructions. |
| 25 | */ |
| 26 | volatile unsigned int ui_one = 1; |
| 27 | long l = 0; |
| 28 | unsigned long ul = 0; |
| 29 | |
| 30 | pr_info("percpu test start\n"); |
| 31 | |
| 32 | preempt_disable(); |
| 33 | |
| 34 | l += -1; |
| 35 | __this_cpu_add(long_counter, -1); |
| 36 | CHECK(l, long_counter, -1); |
| 37 | |
| 38 | l += 1; |
| 39 | __this_cpu_add(long_counter, 1); |
| 40 | CHECK(l, long_counter, 0); |
| 41 | |
| 42 | ul = 0; |
| 43 | __this_cpu_write(ulong_counter, 0); |
| 44 | |
| 45 | ul += 1UL; |
| 46 | __this_cpu_add(ulong_counter, 1UL); |
| 47 | CHECK(ul, ulong_counter, 1); |
| 48 | |
| 49 | ul += -1UL; |
| 50 | __this_cpu_add(ulong_counter, -1UL); |
| 51 | CHECK(ul, ulong_counter, 0); |
| 52 | |
| 53 | ul += -(unsigned long)1; |
| 54 | __this_cpu_add(ulong_counter, -(unsigned long)1); |
| 55 | CHECK(ul, ulong_counter, -1); |
| 56 | |
| 57 | ul = 0; |
| 58 | __this_cpu_write(ulong_counter, 0); |
| 59 | |
| 60 | ul -= 1; |
| 61 | __this_cpu_dec(ulong_counter); |
| 62 | CHECK(ul, ulong_counter, -1); |
| 63 | CHECK(ul, ulong_counter, ULONG_MAX); |
| 64 | |
| 65 | l += -ui_one; |
| 66 | __this_cpu_add(long_counter, -ui_one); |
| 67 | CHECK(l, long_counter, 0xffffffff); |
| 68 | |
| 69 | l += ui_one; |
| 70 | __this_cpu_add(long_counter, ui_one); |
| 71 | CHECK(l, long_counter, (long)0x100000000LL); |
| 72 | |
| 73 | |
| 74 | l = 0; |
| 75 | __this_cpu_write(long_counter, 0); |
| 76 | |
| 77 | l -= ui_one; |
| 78 | __this_cpu_sub(long_counter, ui_one); |
| 79 | CHECK(l, long_counter, -1); |
| 80 | |
| 81 | l = 0; |
| 82 | __this_cpu_write(long_counter, 0); |
| 83 | |
| 84 | l += ui_one; |
| 85 | __this_cpu_add(long_counter, ui_one); |
| 86 | CHECK(l, long_counter, 1); |
| 87 | |
| 88 | l += -ui_one; |
| 89 | __this_cpu_add(long_counter, -ui_one); |
| 90 | CHECK(l, long_counter, (long)0x100000000LL); |
| 91 | |
| 92 | l = 0; |
| 93 | __this_cpu_write(long_counter, 0); |
| 94 | |
| 95 | l -= ui_one; |
| 96 | this_cpu_sub(long_counter, ui_one); |
| 97 | CHECK(l, long_counter, -1); |
| 98 | CHECK(l, long_counter, ULONG_MAX); |
| 99 | |
| 100 | ul = 0; |
| 101 | __this_cpu_write(ulong_counter, 0); |
| 102 | |
| 103 | ul += ui_one; |
| 104 | __this_cpu_add(ulong_counter, ui_one); |
| 105 | CHECK(ul, ulong_counter, 1); |
| 106 | |
| 107 | ul = 0; |
| 108 | __this_cpu_write(ulong_counter, 0); |
| 109 | |
| 110 | ul -= ui_one; |
| 111 | __this_cpu_sub(ulong_counter, ui_one); |
| 112 | CHECK(ul, ulong_counter, -1); |
| 113 | CHECK(ul, ulong_counter, ULONG_MAX); |
| 114 | |
| 115 | ul = 3; |
| 116 | __this_cpu_write(ulong_counter, 3); |
| 117 | |
| 118 | ul = this_cpu_sub_return(ulong_counter, ui_one); |
| 119 | CHECK(ul, ulong_counter, 2); |
| 120 | |
| 121 | ul = __this_cpu_sub_return(ulong_counter, ui_one); |
| 122 | CHECK(ul, ulong_counter, 1); |
| 123 | |
| 124 | preempt_enable(); |
| 125 | |
| 126 | pr_info("percpu test done\n"); |
| 127 | return -EAGAIN; /* Fail will directly unload the module */ |
| 128 | } |
| 129 | |
| 130 | static void __exit percpu_test_exit(void) |
| 131 | { |
| 132 | } |
| 133 | |
| 134 | module_init(percpu_test_init) |
| 135 | module_exit(percpu_test_exit) |
| 136 | |
| 137 | MODULE_LICENSE("GPL"); |
| 138 | MODULE_AUTHOR("Greg Thelen"); |
| 139 | MODULE_DESCRIPTION("percpu operations test"); |