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/**
* Copyright (C) ARM Limited 2014-2015. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include "FtraceDriver.h"
#include <regex.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "Config.h"
#include "DriverSource.h"
#include "Logging.h"
#include "SessionData.h"
#include "Setup.h"
class FtraceCounter : public DriverCounter {
public:
FtraceCounter(DriverCounter *next, char *name, const char *enable);
~FtraceCounter();
void prepare();
void stop();
private:
char *const mEnable;
int mWasEnabled;
// Intentionally unimplemented
FtraceCounter(const FtraceCounter &);
FtraceCounter &operator=(const FtraceCounter &);
};
FtraceCounter::FtraceCounter(DriverCounter *next, char *name, const char *enable) : DriverCounter(next, name), mEnable(enable == NULL ? NULL : strdup(enable)) {
}
FtraceCounter::~FtraceCounter() {
if (mEnable != NULL) {
free(mEnable);
}
}
void FtraceCounter::prepare() {
if (mEnable == NULL) {
return;
}
char buf[1<<10];
snprintf(buf, sizeof(buf), EVENTS_PATH "/%s/enable", mEnable);
if ((DriverSource::readIntDriver(buf, &mWasEnabled) != 0) ||
(DriverSource::writeDriver(buf, 1) != 0)) {
logg->logError("Unable to read or write to %s", buf);
handleException();
}
}
void FtraceCounter::stop() {
if (mEnable == NULL) {
return;
}
char buf[1<<10];
snprintf(buf, sizeof(buf), EVENTS_PATH "/%s/enable", mEnable);
DriverSource::writeDriver(buf, mWasEnabled);
}
FtraceDriver::FtraceDriver() : mValues(NULL), mSupported(false), mTracingOn(0) {
}
FtraceDriver::~FtraceDriver() {
delete [] mValues;
}
void FtraceDriver::readEvents(mxml_node_t *const xml) {
// Check the kernel version
int release[3];
if (!getLinuxVersion(release)) {
logg->logError("getLinuxVersion failed");
handleException();
}
// The perf clock was added in 3.10
if (KERNEL_VERSION(release[0], release[1], release[2]) < KERNEL_VERSION(3, 10, 0)) {
mSupported = false;
logg->logMessage("Unsupported kernel version, to use ftrace please upgrade to Linux 3.10 or later");
return;
}
// Is debugfs or tracefs available?
if (access(TRACING_PATH, R_OK) != 0) {
mSupported = false;
logg->logMessage("Unable to locate the tracing directory, disabling ftrace");
return;
}
mSupported = true;
mxml_node_t *node = xml;
int count = 0;
while (true) {
node = mxmlFindElement(node, xml, "event", NULL, NULL, MXML_DESCEND);
if (node == NULL) {
break;
}
const char *counter = mxmlElementGetAttr(node, "counter");
if (counter == NULL) {
continue;
}
if (strncmp(counter, "ftrace_", 7) != 0) {
continue;
}
const char *regex = mxmlElementGetAttr(node, "regex");
if (regex == NULL) {
logg->logError("The regex counter %s is missing the required regex attribute", counter);
handleException();
}
const char *tracepoint = mxmlElementGetAttr(node, "tracepoint");
const char *enable = mxmlElementGetAttr(node, "enable");
if (enable == NULL) {
enable = tracepoint;
}
if (gSessionData->mPerf.isSetup() && tracepoint != NULL) {
logg->logMessage("Not using ftrace for counter %s", counter);
continue;
}
if (enable != NULL) {
char buf[1<<10];
snprintf(buf, sizeof(buf), EVENTS_PATH "/%s/enable", enable);
if (access(buf, W_OK) != 0) {
logg->logMessage("Disabling counter %s, %s not found", counter, buf);
continue;
}
}
logg->logMessage("Using ftrace for %s", counter);
setCounters(new FtraceCounter(getCounters(), strdup(counter), enable));
++count;
}
mValues = new int64_t[2*count];
}
void FtraceDriver::prepare() {
for (FtraceCounter *counter = static_cast<FtraceCounter *>(getCounters()); counter != NULL; counter = static_cast<FtraceCounter *>(counter->getNext())) {
if (!counter->isEnabled()) {
continue;
}
counter->prepare();
}
if (DriverSource::readIntDriver(TRACING_PATH "/tracing_on", &mTracingOn)) {
logg->logError("Unable to read if ftrace is enabled");
handleException();
}
if (DriverSource::writeDriver(TRACING_PATH "/tracing_on", "0") != 0) {
logg->logError("Unable to turn ftrace off before truncating the buffer");
handleException();
}
{
int fd;
fd = open(TRACING_PATH "/trace", O_WRONLY | O_TRUNC | O_CLOEXEC, 0666);
if (fd < 0) {
logg->logError("Unable truncate ftrace buffer: %s", strerror(errno));
handleException();
}
close(fd);
}
if (DriverSource::writeDriver(TRACING_PATH "/trace_clock", "perf") != 0) {
logg->logError("Unable to switch ftrace to the perf clock, please ensure you are running Linux 3.10 or later");
handleException();
}
}
void FtraceDriver::stop() {
DriverSource::writeDriver(TRACING_PATH "/tracing_on", mTracingOn);
DriverSource::writeDriver(TRACING_PATH "/trace_clock", "local");
for (FtraceCounter *counter = static_cast<FtraceCounter *>(getCounters()); counter != NULL; counter = static_cast<FtraceCounter *>(counter->getNext())) {
if (!counter->isEnabled()) {
continue;
}
counter->stop();
}
}
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