--- /dev/null
+/*
+ * perf events self profiling example test case for hw breakpoints.
+ *
+ * This tests perf PERF_TYPE_BREAKPOINT parameters
+ * 1) tests all variants of the break on read/write flags
+ * 2) tests exclude_user == 0 and 1
+ * 3) test array matches (if DAWR is supported))
+ * 4) test different numbers of breakpoints matches
+ *
+ * Configure this breakpoint, then read and write the data a number of
+ * times. Then check the output count from perf is as expected.
+ *
+ * Based on:
+ * http://ozlabs.org/~anton/junkcode/perf_events_example1.c
+ *
+ * Copyright (C) 2018 Michael Neuling, IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <unistd.h>
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <elf.h>
+#include <pthread.h>
+#include <sys/syscall.h>
+#include <linux/perf_event.h>
+#include <linux/hw_breakpoint.h>
+#include "utils.h"
+
+#define MAX_LOOPS 10000
+
+#define DAWR_LENGTH_MAX ((0x3f + 1) * 8)
+
+static inline int sys_perf_event_open(struct perf_event_attr *attr, pid_t pid,
+ int cpu, int group_fd,
+ unsigned long flags)
+{
+ attr->size = sizeof(*attr);
+ return syscall(__NR_perf_event_open, attr, pid, cpu, group_fd, flags);
+}
+
+static inline bool breakpoint_test(int len)
+{
+ struct perf_event_attr attr;
+ int fd;
+
+ /* setup counters */
+ memset(&attr, 0, sizeof(attr));
+ attr.disabled = 1;
+ attr.type = PERF_TYPE_BREAKPOINT;
+ attr.bp_type = HW_BREAKPOINT_R;
+ /* bp_addr can point anywhere but needs to be aligned */
+ attr.bp_addr = (__u64)(&attr) & 0xfffffffffffff800;
+ attr.bp_len = len;
+ fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
+ if (fd < 0)
+ return false;
+ close(fd);
+ return true;
+}
+
+static inline bool perf_breakpoint_supported(void)
+{
+ return breakpoint_test(4);
+}
+
+static inline bool dawr_supported(void)
+{
+ return breakpoint_test(DAWR_LENGTH_MAX);
+}
+
+static int runtestsingle(int readwriteflag, int exclude_user, int arraytest)
+{
+ int i,j;
+ struct perf_event_attr attr;
+ size_t res;
+ unsigned long long breaks, needed;
+ int readint;
+ int readintarraybig[2*DAWR_LENGTH_MAX/sizeof(int)];
+ int *readintalign;
+ volatile int *ptr;
+ int break_fd;
+ int loop_num = MAX_LOOPS - (rand() % 100); /* provide some variability */
+ volatile int *k;
+
+ /* align to 0x400 boundary as required by DAWR */
+ readintalign = (int *)(((unsigned long)readintarraybig + 0x7ff) &
+ 0xfffffffffffff800);
+
+ ptr = &readint;
+ if (arraytest)
+ ptr = &readintalign[0];
+
+ /* setup counters */
+ memset(&attr, 0, sizeof(attr));
+ attr.disabled = 1;
+ attr.type = PERF_TYPE_BREAKPOINT;
+ attr.bp_type = readwriteflag;
+ attr.bp_addr = (__u64)ptr;
+ attr.bp_len = sizeof(int);
+ if (arraytest)
+ attr.bp_len = DAWR_LENGTH_MAX;
+ attr.exclude_user = exclude_user;
+ break_fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
+ if (break_fd < 0) {
+ perror("sys_perf_event_open");
+ exit(1);
+ }
+
+ /* start counters */
+ ioctl(break_fd, PERF_EVENT_IOC_ENABLE);
+
+ /* Test a bunch of reads and writes */
+ k = &readint;
+ for (i = 0; i < loop_num; i++) {
+ if (arraytest)
+ k = &(readintalign[i % (DAWR_LENGTH_MAX/sizeof(int))]);
+
+ j = *k;
+ *k = j;
+ }
+
+ /* stop counters */
+ ioctl(break_fd, PERF_EVENT_IOC_DISABLE);
+
+ /* read and check counters */
+ res = read(break_fd, &breaks, sizeof(unsigned long long));
+ assert(res == sizeof(unsigned long long));
+ /* we read and write each loop, so subtract the ones we are counting */
+ needed = 0;
+ if (readwriteflag & HW_BREAKPOINT_R)
+ needed += loop_num;
+ if (readwriteflag & HW_BREAKPOINT_W)
+ needed += loop_num;
+ needed = needed * (1 - exclude_user);
+ printf("TESTED: addr:0x%lx brks:% 8lld loops:% 8i rw:%i !user:%i array:%i\n",
+ (unsigned long int)ptr, breaks, loop_num, readwriteflag, exclude_user, arraytest);
+ if (breaks != needed) {
+ printf("FAILED: 0x%lx brks:%lld needed:%lli %i %i %i\n\n",
+ (unsigned long int)ptr, breaks, needed, loop_num, readwriteflag, exclude_user);
+ return 1;
+ }
+ close(break_fd);
+
+ return 0;
+}
+
+static int runtest(void)
+{
+ int rwflag;
+ int exclude_user;
+ int ret;
+
+ /*
+ * perf defines rwflag as two bits read and write and at least
+ * one must be set. So range 1-3.
+ */
+ for (rwflag = 1 ; rwflag < 4; rwflag++) {
+ for (exclude_user = 0 ; exclude_user < 2; exclude_user++) {
+ ret = runtestsingle(rwflag, exclude_user, 0);
+ if (ret)
+ return ret;
+
+ /* if we have the dawr, we can do an array test */
+ if (!dawr_supported())
+ continue;
+ ret = runtestsingle(rwflag, exclude_user, 1);
+ if (ret)
+ return ret;
+ }
+ }
+ return 0;
+}
+
+
+static int perf_hwbreak(void)
+{
+ srand ( time(NULL) );
+
+ SKIP_IF(!perf_breakpoint_supported());
+
+ return runtest();
+}
+
+int main(int argc, char *argv[], char **envp)
+{
+ return test_harness(perf_hwbreak, "perf_hwbreak");
+}
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