tools/testing/selftests/user_events/abi_test.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * User Events ABI Test Program
   4  *
   5  * Copyright (c) 2022 Beau Belgrave <beaub@linux.microsoft.com>
   6  */
   7
   8 #define _GNU_SOURCE
   9 #include <sched.h>
  10
  11 #include <errno.h>
  12 #include <linux/user_events.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <fcntl.h>
  16 #include <sys/ioctl.h>
  17 #include <sys/stat.h>
  18 #include <unistd.h>
  19 #include <asm/unistd.h>
  20
  21 #include "../kselftest_harness.h"
  22 #include "user_events_selftests.h"
  23
  24 const char *data_file = "/sys/kernel/tracing/user_events_data";
  25 const char *enable_file = "/sys/kernel/tracing/events/user_events/__abi_event/enable";
  26
  27 static int change_event(bool enable)
  28 {
  29         int fd = open(enable_file, O_RDWR);
  30         int ret;
  31
  32         if (fd < 0)
  33                 return -1;
  34
  35         if (enable)
  36                 ret = write(fd, "1", 1);
  37         else
  38                 ret = write(fd, "0", 1);
  39
  40         close(fd);
  41
  42         if (ret == 1)
  43                 ret = 0;
  44         else
  45                 ret = -1;
  46
  47         return ret;
  48 }
  49
  50 static int reg_enable(long *enable, int size, int bit)
  51 {
  52         struct user_reg reg = {0};
  53         int fd = open(data_file, O_RDWR);
  54         int ret;
  55
  56         if (fd < 0)
  57                 return -1;
  58
  59         reg.size = sizeof(reg);
  60         reg.name_args = (__u64)"__abi_event";
  61         reg.enable_bit = bit;
  62         reg.enable_addr = (__u64)enable;
  63         reg.enable_size = size;
  64
  65         ret = ioctl(fd, DIAG_IOCSREG, &reg);
  66
  67         close(fd);
  68
  69         return ret;
  70 }
  71
  72 static int reg_disable(long *enable, int bit)
  73 {
  74         struct user_unreg reg = {0};
  75         int fd = open(data_file, O_RDWR);
  76         int ret;
  77
  78         if (fd < 0)
  79                 return -1;
  80
  81         reg.size = sizeof(reg);
  82         reg.disable_bit = bit;
  83         reg.disable_addr = (__u64)enable;
  84
  85         ret = ioctl(fd, DIAG_IOCSUNREG, &reg);
  86
  87         close(fd);
  88
  89         return ret;
  90 }
  91
  92 FIXTURE(user) {
  93         long check;
  94 };
  95
  96 FIXTURE_SETUP(user) {
  97         USER_EVENT_FIXTURE_SETUP(return);
  98
  99         change_event(false);
 100         self->check = 0;
 101 }
 102
 103 FIXTURE_TEARDOWN(user) {
 104 }
 105
 106 TEST_F(user, enablement) {
 107         /* Changes should be reflected immediately */
 108         ASSERT_EQ(0, self->check);
 109         ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0));
 110         ASSERT_EQ(0, change_event(true));
 111         ASSERT_EQ(1, self->check);
 112         ASSERT_EQ(0, change_event(false));
 113         ASSERT_EQ(0, self->check);
 114
 115         /* Ensure kernel clears bit after disable */
 116         ASSERT_EQ(0, change_event(true));
 117         ASSERT_EQ(1, self->check);
 118         ASSERT_EQ(0, reg_disable(&self->check, 0));
 119         ASSERT_EQ(0, self->check);
 120
 121         /* Ensure doesn't change after unreg */
 122         ASSERT_EQ(0, change_event(true));
 123         ASSERT_EQ(0, self->check);
 124         ASSERT_EQ(0, change_event(false));
 125 }
 126
 127 TEST_F(user, bit_sizes) {
 128         /* Allow 0-31 bits for 32-bit */
 129         ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0));
 130         ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 31));
 131         ASSERT_NE(0, reg_enable(&self->check, sizeof(int), 32));
 132         ASSERT_EQ(0, reg_disable(&self->check, 0));
 133         ASSERT_EQ(0, reg_disable(&self->check, 31));
 134
 135 #if BITS_PER_LONG == 8
 136         /* Allow 0-64 bits for 64-bit */
 137         ASSERT_EQ(0, reg_enable(&self->check, sizeof(long), 63));
 138         ASSERT_NE(0, reg_enable(&self->check, sizeof(long), 64));
 139         ASSERT_EQ(0, reg_disable(&self->check, 63));
 140 #endif
 141
 142         /* Disallowed sizes (everything beside 4 and 8) */
 143         ASSERT_NE(0, reg_enable(&self->check, 1, 0));
 144         ASSERT_NE(0, reg_enable(&self->check, 2, 0));
 145         ASSERT_NE(0, reg_enable(&self->check, 3, 0));
 146         ASSERT_NE(0, reg_enable(&self->check, 5, 0));
 147         ASSERT_NE(0, reg_enable(&self->check, 6, 0));
 148         ASSERT_NE(0, reg_enable(&self->check, 7, 0));
 149         ASSERT_NE(0, reg_enable(&self->check, 9, 0));
 150         ASSERT_NE(0, reg_enable(&self->check, 128, 0));
 151 }
 152
 153 TEST_F(user, forks) {
 154         int i;
 155
 156         /* Ensure COW pages get updated after fork */
 157         ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0));
 158         ASSERT_EQ(0, self->check);
 159
 160         if (fork() == 0) {
 161                 /* Force COW */
 162                 self->check = 0;
 163
 164                 /* Up to 1 sec for enablement */
 165                 for (i = 0; i < 10; ++i) {
 166                         usleep(100000);
 167
 168                         if (self->check)
 169                                 exit(0);
 170                 }
 171
 172                 exit(1);
 173         }
 174
 175         /* Allow generous time for COW, then enable */
 176         usleep(100000);
 177         ASSERT_EQ(0, change_event(true));
 178
 179         ASSERT_NE(-1, wait(&i));
 180         ASSERT_EQ(0, WEXITSTATUS(i));
 181
 182         /* Ensure child doesn't disable parent */
 183         if (fork() == 0)
 184                 exit(reg_disable(&self->check, 0));
 185
 186         ASSERT_NE(-1, wait(&i));
 187         ASSERT_EQ(0, WEXITSTATUS(i));
 188         ASSERT_EQ(1, self->check);
 189         ASSERT_EQ(0, change_event(false));
 190         ASSERT_EQ(0, self->check);
 191 }
 192
 193 /* Waits up to 1 sec for enablement */
 194 static int clone_check(void *check)
 195 {
 196         int i;
 197
 198         for (i = 0; i < 10; ++i) {
 199                 usleep(100000);
 200
 201                 if (*(long *)check)
 202                         return 0;
 203         }
 204
 205         return 1;
 206 }
 207
 208 TEST_F(user, clones) {
 209         int i, stack_size = 4096;
 210         void *stack = mmap(NULL, stack_size, PROT_READ | PROT_WRITE,
 211                            MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK,
 212                            -1, 0);
 213
 214         ASSERT_NE(MAP_FAILED, stack);
 215         ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0));
 216         ASSERT_EQ(0, self->check);
 217
 218         /* Shared VM should see enablements */
 219         ASSERT_NE(-1, clone(&clone_check, stack + stack_size,
 220                             CLONE_VM | SIGCHLD, &self->check));
 221
 222         ASSERT_EQ(0, change_event(true));
 223         ASSERT_NE(-1, wait(&i));
 224         ASSERT_EQ(0, WEXITSTATUS(i));
 225         munmap(stack, stack_size);
 226         ASSERT_EQ(0, change_event(false));
 227 }
 228
 229 int main(int argc, char **argv)
 230 {
 231         return test_harness_run(argc, argv);
 232 }