root/tools/perf/tests/bp_account.c

DEFINITIONS

1. test_function
2. __event
3. wp_event
4. bp_event
5. bp_accounting
6. detect_cnt
7. detect_ioctl
8. detect_share
9. test__bp_accounting

   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 <time.h>
  14 #include <fcntl.h>
  15 #include <signal.h>
  16 #include <sys/mman.h>
  17 #include <linux/compiler.h>
  18 #include <linux/hw_breakpoint.h>
  19 
  20 #include "tests.h"
  21 #include "debug.h"
  22 #include "event.h"
  23 #include "../perf-sys.h"
  24 #include "cloexec.h"
  25 
  26 volatile long the_var;
  27 
  28 static noinline int test_function(void)
  29 {
  30         return 0;
  31 }
  32 
  33 static int __event(bool is_x, void *addr, struct perf_event_attr *attr)
  34 {
  35         int fd;
  36 
  37         memset(attr, 0, sizeof(struct perf_event_attr));
  38         attr->type = PERF_TYPE_BREAKPOINT;
  39         attr->size = sizeof(struct perf_event_attr);
  40 
  41         attr->config = 0;
  42         attr->bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
  43         attr->bp_addr = (unsigned long) addr;
  44         attr->bp_len = sizeof(long);
  45 
  46         attr->sample_period = 1;
  47         attr->sample_type = PERF_SAMPLE_IP;
  48 
  49         attr->exclude_kernel = 1;
  50         attr->exclude_hv = 1;
  51 
  52         fd = sys_perf_event_open(attr, -1, 0, -1,
  53                                  perf_event_open_cloexec_flag());
  54         if (fd < 0) {
  55                 pr_debug("failed opening event %llx\n", attr->config);
  56                 return TEST_FAIL;
  57         }
  58 
  59         return fd;
  60 }
  61 
  62 static int wp_event(void *addr, struct perf_event_attr *attr)
  63 {
  64         return __event(false, addr, attr);
  65 }
  66 
  67 static int bp_event(void *addr, struct perf_event_attr *attr)
  68 {
  69         return __event(true, addr, attr);
  70 }
  71 
  72 static int bp_accounting(int wp_cnt, int share)
  73 {
  74         struct perf_event_attr attr, attr_mod, attr_new;
  75         int i, fd[wp_cnt], fd_wp, ret;
  76 
  77         for (i = 0; i < wp_cnt; i++) {
  78                 fd[i] = wp_event((void *)&the_var, &attr);
  79                 TEST_ASSERT_VAL("failed to create wp\n", fd[i] != -1);
  80                 pr_debug("wp %d created\n", i);
  81         }
  82 
  83         attr_mod = attr;
  84         attr_mod.bp_type = HW_BREAKPOINT_X;
  85         attr_mod.bp_addr = (unsigned long) test_function;
  86 
  87         ret = ioctl(fd[0], PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr_mod);
  88         TEST_ASSERT_VAL("failed to modify wp\n", ret == 0);
  89 
  90         pr_debug("wp 0 modified to bp\n");
  91 
  92         if (!share) {
  93                 fd_wp = wp_event((void *)&the_var, &attr_new);
  94                 TEST_ASSERT_VAL("failed to create max wp\n", fd_wp != -1);
  95                 pr_debug("wp max created\n");
  96         }
  97 
  98         for (i = 0; i < wp_cnt; i++)
  99                 close(fd[i]);
 100 
 101         return 0;
 102 }
 103 
 104 static int detect_cnt(bool is_x)
 105 {
 106         struct perf_event_attr attr;
 107         void *addr = is_x ? (void *)test_function : (void *)&the_var;
 108         int fd[100], cnt = 0, i;
 109 
 110         while (1) {
 111                 if (cnt == 100) {
 112                         pr_debug("way too many debug registers, fix the test\n");
 113                         return 0;
 114                 }
 115                 fd[cnt] = __event(is_x, addr, &attr);
 116 
 117                 if (fd[cnt] < 0)
 118                         break;
 119                 cnt++;
 120         }
 121 
 122         for (i = 0; i < cnt; i++)
 123                 close(fd[i]);
 124 
 125         return cnt;
 126 }
 127 
 128 static int detect_ioctl(void)
 129 {
 130         struct perf_event_attr attr;
 131         int fd, ret = 1;
 132 
 133         fd = wp_event((void *) &the_var, &attr);
 134         if (fd > 0) {
 135                 ret = ioctl(fd, PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr);
 136                 close(fd);
 137         }
 138 
 139         return ret ? 0 : 1;
 140 }
 141 
 142 static int detect_share(int wp_cnt, int bp_cnt)
 143 {
 144         struct perf_event_attr attr;
 145         int i, fd[wp_cnt + bp_cnt], ret;
 146 
 147         for (i = 0; i < wp_cnt; i++) {
 148                 fd[i] = wp_event((void *)&the_var, &attr);
 149                 TEST_ASSERT_VAL("failed to create wp\n", fd[i] != -1);
 150         }
 151 
 152         for (; i < (bp_cnt + wp_cnt); i++) {
 153                 fd[i] = bp_event((void *)test_function, &attr);
 154                 if (fd[i] == -1)
 155                         break;
 156         }
 157 
 158         ret = i != (bp_cnt + wp_cnt);
 159 
 160         while (i--)
 161                 close(fd[i]);
 162 
 163         return ret;
 164 }
 165 
 166 /*
 167  * This test does following:
 168  *   - detects the number of watch/break-points,
 169  *     skip test if any is missing
 170  *   - detects PERF_EVENT_IOC_MODIFY_ATTRIBUTES ioctl,
 171  *     skip test if it's missing
 172  *   - detects if watchpoints and breakpoints share
 173  *     same slots
 174  *   - create all possible watchpoints on cpu 0
 175  *   - change one of it to breakpoint
 176  *   - in case wp and bp do not share slots,
 177  *     we create another watchpoint to ensure
 178  *     the slot accounting is correct
 179  */
 180 int test__bp_accounting(struct test *test __maybe_unused, int subtest __maybe_unused)
 181 {
 182         int has_ioctl = detect_ioctl();
 183         int wp_cnt = detect_cnt(false);
 184         int bp_cnt = detect_cnt(true);
 185         int share  = detect_share(wp_cnt, bp_cnt);
 186 
 187         pr_debug("watchpoints count %d, breakpoints count %d, has_ioctl %d, share %d\n",
 188                  wp_cnt, bp_cnt, has_ioctl, share);
 189 
 190         if (!wp_cnt || !bp_cnt || !has_ioctl)
 191                 return TEST_SKIP;
 192 
 193         return bp_accounting(wp_cnt, share);
 194 }