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 #include <sys/ioctl.h>
  19
  20 #include "tests.h"
  21 #include "debug.h"
  22 #include "perf.h"
  23 #include "cloexec.h"
  24
  25 volatile long the_var;
  26
  27 static noinline int test_function(void)
  28 {
  29         return 0;
  30 }
  31
  32 static int __event(bool is_x, void *addr, struct perf_event_attr *attr)
  33 {
  34         int fd;
  35
  36         memset(attr, 0, sizeof(struct perf_event_attr));
  37         attr->type = PERF_TYPE_BREAKPOINT;
  38         attr->size = sizeof(struct perf_event_attr);
  39
  40         attr->config = 0;
  41         attr->bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
  42         attr->bp_addr = (unsigned long) addr;
  43         attr->bp_len = sizeof(long);
  44
  45         attr->sample_period = 1;
  46         attr->sample_type = PERF_SAMPLE_IP;
  47
  48         attr->exclude_kernel = 1;
  49         attr->exclude_hv = 1;
  50
  51         fd = sys_perf_event_open(attr, -1, 0, -1,
  52                                  perf_event_open_cloexec_flag());
  53         if (fd < 0) {
  54                 pr_debug("failed opening event %llx\n", attr->config);
  55                 return TEST_FAIL;
  56         }
  57
  58         return fd;
  59 }
  60
  61 static int wp_event(void *addr, struct perf_event_attr *attr)
  62 {
  63         return __event(false, addr, attr);
  64 }
  65
  66 static int bp_event(void *addr, struct perf_event_attr *attr)
  67 {
  68         return __event(true, addr, attr);
  69 }
  70
  71 static int bp_accounting(int wp_cnt, int share)
  72 {
  73         struct perf_event_attr attr, attr_mod, attr_new;
  74         int i, fd[wp_cnt], fd_wp, ret;
  75
  76         for (i = 0; i < wp_cnt; i++) {
  77                 fd[i] = wp_event((void *)&the_var, &attr);
  78                 TEST_ASSERT_VAL("failed to create wp\n", fd[i] != -1);
  79                 pr_debug("wp %d created\n", i);
  80         }
  81
  82         attr_mod = attr;
  83         attr_mod.bp_type = HW_BREAKPOINT_X;
  84         attr_mod.bp_addr = (unsigned long) test_function;
  85
  86         ret = ioctl(fd[0], PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr_mod);
  87         TEST_ASSERT_VAL("failed to modify wp\n", ret == 0);
  88
  89         pr_debug("wp 0 modified to bp\n");
  90
  91         if (!share) {
  92                 fd_wp = wp_event((void *)&the_var, &attr_new);
  93                 TEST_ASSERT_VAL("failed to create max wp\n", fd_wp != -1);
  94                 pr_debug("wp max created\n");
  95         }
  96
  97         for (i = 0; i < wp_cnt; i++)
  98                 close(fd[i]);
  99
 100         return 0;
 101 }
 102
 103 static int detect_cnt(bool is_x)
 104 {
 105         struct perf_event_attr attr;
 106         void *addr = is_x ? (void *)test_function : (void *)&the_var;
 107         int fd[100], cnt = 0, i;
 108
 109         while (1) {
 110                 if (cnt == 100) {
 111                         pr_debug("way too many debug registers, fix the test\n");
 112                         return 0;
 113                 }
 114                 fd[cnt] = __event(is_x, addr, &attr);
 115
 116                 if (fd[cnt] < 0)
 117                         break;
 118                 cnt++;
 119         }
 120
 121         for (i = 0; i < cnt; i++)
 122                 close(fd[i]);
 123
 124         return cnt;
 125 }
 126
 127 static int detect_ioctl(void)
 128 {
 129         struct perf_event_attr attr;
 130         int fd, ret = 1;
 131
 132         fd = wp_event((void *) &the_var, &attr);
 133         if (fd > 0) {
 134                 ret = ioctl(fd, PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr);
 135                 close(fd);
 136         }
 137
 138         return ret ? 0 : 1;
 139 }
 140
 141 static int detect_share(int wp_cnt, int bp_cnt)
 142 {
 143         struct perf_event_attr attr;
 144         int i, fd[wp_cnt + bp_cnt], ret;
 145
 146         for (i = 0; i < wp_cnt; i++) {
 147                 fd[i] = wp_event((void *)&the_var, &attr);
 148                 TEST_ASSERT_VAL("failed to create wp\n", fd[i] != -1);
 149         }
 150
 151         for (; i < (bp_cnt + wp_cnt); i++) {
 152                 fd[i] = bp_event((void *)test_function, &attr);
 153                 if (fd[i] == -1)
 154                         break;
 155         }
 156
 157         ret = i != (bp_cnt + wp_cnt);
 158
 159         while (i--)
 160                 close(fd[i]);
 161
 162         return ret;
 163 }
 164
 165 /*
 166  * This test does following:
 167  *   - detects the number of watch/break-points,
 168  *     skip test if any is missing
 169  *   - detects PERF_EVENT_IOC_MODIFY_ATTRIBUTES ioctl,
 170  *     skip test if it's missing
 171  *   - detects if watchpoints and breakpoints share
 172  *     same slots
 173  *   - create all possible watchpoints on cpu 0
 174  *   - change one of it to breakpoint
 175  *   - in case wp and bp do not share slots,
 176  *     we create another watchpoint to ensure
 177  *     the slot accounting is correct
 178  */
 179 int test__bp_accounting(struct test *test __maybe_unused, int subtest __maybe_unused)
 180 {
 181         int has_ioctl = detect_ioctl();
 182         int wp_cnt = detect_cnt(false);
 183         int bp_cnt = detect_cnt(true);
 184         int share  = detect_share(wp_cnt, bp_cnt);
 185
 186         pr_debug("watchpoints count %d, breakpoints count %d, has_ioctl %d, share %d\n",
 187                  wp_cnt, bp_cnt, has_ioctl, share);
 188
 189         if (!wp_cnt || !bp_cnt || !has_ioctl)
 190                 return TEST_SKIP;
 191
 192         return bp_accounting(wp_cnt, share);
 193 }