tools/perf/tests/bp_account.c

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