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/*
* 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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