tools/perf/tests/bp_account.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Powerpc needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select
   4  * 'int-ll64.h' and avoid compile warnings when printing __u64 with %llu.
   5  */
   6 #define __SANE_USERSPACE_TYPES__
   7
   8 #include <stdlib.h>
   9 #include <stdio.h>
  10 #include <unistd.h>
  11 #include <string.h>
  12 #include <sys/ioctl.h>
  13 #include <fcntl.h>
  14 #include <linux/hw_breakpoint.h>
  15
  16 #include "tests.h"
  17 #include "debug.h"
  18 #include "event.h"
  19 #include "parse-events.h"
  20 #include "../perf-sys.h"
  21 #include "cloexec.h"
  22
  23 /*
  24  * PowerPC and S390 do not support creation of instruction breakpoints using the
  25  * perf_event interface.
  26  *
  27  * Just disable the test for these architectures until these issues are
  28  * resolved.
  29  */
  30 #if defined(__powerpc__) || defined(__s390x__)
  31 #define BP_ACCOUNT_IS_SUPPORTED 0
  32 #else
  33 #define BP_ACCOUNT_IS_SUPPORTED 1
  34 #endif
  35
  36 static volatile long the_var;
  37
  38 static noinline int test_function(void)
  39 {
  40         return 0;
  41 }
  42
  43 static int __event(bool is_x, void *addr, struct perf_event_attr *attr)
  44 {
  45         int fd;
  46
  47         memset(attr, 0, sizeof(struct perf_event_attr));
  48         attr->type = PERF_TYPE_BREAKPOINT;
  49         attr->size = sizeof(struct perf_event_attr);
  50
  51         attr->config = 0;
  52         attr->bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
  53         attr->bp_addr = (unsigned long) addr;
  54         attr->bp_len = is_x ? default_breakpoint_len() : sizeof(long);
  55
  56         attr->sample_period = 1;
  57         attr->sample_type = PERF_SAMPLE_IP;
  58
  59         attr->exclude_kernel = 1;
  60         attr->exclude_hv = 1;
  61
  62         fd = sys_perf_event_open(attr, -1, 0, -1,
  63                                  perf_event_open_cloexec_flag());
  64         if (fd < 0) {
  65                 pr_debug("failed opening event %llx\n", attr->config);
  66                 return TEST_FAIL;
  67         }
  68
  69         return fd;
  70 }
  71
  72 static int wp_event(void *addr, struct perf_event_attr *attr)
  73 {
  74         return __event(false, addr, attr);
  75 }
  76
  77 static int bp_event(void *addr, struct perf_event_attr *attr)
  78 {
  79         return __event(true, addr, attr);
  80 }
  81
  82 static int bp_accounting(int wp_cnt, int share)
  83 {
  84         struct perf_event_attr attr, attr_mod, attr_new;
  85         int i, fd[wp_cnt], fd_wp, ret;
  86
  87         for (i = 0; i < wp_cnt; i++) {
  88                 fd[i] = wp_event((void *)&the_var, &attr);
  89                 TEST_ASSERT_VAL("failed to create wp\n", fd[i] != -1);
  90                 pr_debug("wp %d created\n", i);
  91         }
  92
  93         attr_mod = attr;
  94         attr_mod.bp_type = HW_BREAKPOINT_X;
  95         attr_mod.bp_addr = (unsigned long) test_function;
  96         attr_mod.bp_len = default_breakpoint_len();
  97
  98         ret = ioctl(fd[0], PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr_mod);
  99         TEST_ASSERT_VAL("failed to modify wp\n", ret == 0);
 100
 101         pr_debug("wp 0 modified to bp\n");
 102
 103         if (!share) {
 104                 fd_wp = wp_event((void *)&the_var, &attr_new);
 105                 TEST_ASSERT_VAL("failed to create max wp\n", fd_wp != -1);
 106                 pr_debug("wp max created\n");
 107         }
 108
 109         for (i = 0; i < wp_cnt; i++)
 110                 close(fd[i]);
 111
 112         return 0;
 113 }
 114
 115 static int detect_cnt(bool is_x)
 116 {
 117         struct perf_event_attr attr;
 118         void *addr = is_x ? (void *)test_function : (void *)&the_var;
 119         int fd[100], cnt = 0, i;
 120
 121         while (1) {
 122                 if (cnt == 100) {
 123                         pr_debug("way too many debug registers, fix the test\n");
 124                         return 0;
 125                 }
 126                 fd[cnt] = __event(is_x, addr, &attr);
 127
 128                 if (fd[cnt] < 0)
 129                         break;
 130                 cnt++;
 131         }
 132
 133         for (i = 0; i < cnt; i++)
 134                 close(fd[i]);
 135
 136         return cnt;
 137 }
 138
 139 static int detect_ioctl(void)
 140 {
 141         struct perf_event_attr attr;
 142         int fd, ret = 1;
 143
 144         fd = wp_event((void *) &the_var, &attr);
 145         if (fd > 0) {
 146                 ret = ioctl(fd, PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr);
 147                 close(fd);
 148         }
 149
 150         return ret ? 0 : 1;
 151 }
 152
 153 static int detect_share(int wp_cnt, int bp_cnt)
 154 {
 155         struct perf_event_attr attr;
 156         int i, *fd = NULL, ret = -1;
 157
 158         if (wp_cnt + bp_cnt == 0)
 159                 return 0;
 160
 161         fd = malloc(sizeof(int) * (wp_cnt + bp_cnt));
 162         if (!fd)
 163                 return -1;
 164
 165         for (i = 0; i < wp_cnt; i++) {
 166                 fd[i] = wp_event((void *)&the_var, &attr);
 167                 if (fd[i] == -1) {
 168                         pr_err("failed to create wp\n");
 169                         goto out;
 170                 }
 171         }
 172
 173         for (; i < (bp_cnt + wp_cnt); i++) {
 174                 fd[i] = bp_event((void *)test_function, &attr);
 175                 if (fd[i] == -1)
 176                         break;
 177         }
 178
 179         ret = i != (bp_cnt + wp_cnt);
 180
 181 out:
 182         while (i--)
 183                 close(fd[i]);
 184
 185         free(fd);
 186         return ret;
 187 }
 188
 189 /*
 190  * This test does following:
 191  *   - detects the number of watch/break-points,
 192  *     skip test if any is missing
 193  *   - detects PERF_EVENT_IOC_MODIFY_ATTRIBUTES ioctl,
 194  *     skip test if it's missing
 195  *   - detects if watchpoints and breakpoints share
 196  *     same slots
 197  *   - create all possible watchpoints on cpu 0
 198  *   - change one of it to breakpoint
 199  *   - in case wp and bp do not share slots,
 200  *     we create another watchpoint to ensure
 201  *     the slot accounting is correct
 202  */
 203 static int test__bp_accounting(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
 204 {
 205         int has_ioctl = detect_ioctl();
 206         int wp_cnt = detect_cnt(false);
 207         int bp_cnt = detect_cnt(true);
 208         int share  = detect_share(wp_cnt, bp_cnt);
 209
 210         if (!BP_ACCOUNT_IS_SUPPORTED) {
 211                 pr_debug("Test not supported on this architecture");
 212                 return TEST_SKIP;
 213         }
 214
 215         pr_debug("watchpoints count %d, breakpoints count %d, has_ioctl %d, share %d\n",
 216                  wp_cnt, bp_cnt, has_ioctl, share);
 217
 218         if (!wp_cnt || !bp_cnt || !has_ioctl)
 219                 return TEST_SKIP;
 220
 221         return bp_accounting(wp_cnt, share);
 222 }
 223
 224 DEFINE_SUITE("Breakpoint accounting", bp_accounting);