From: Alexander Shishkin alexander.shishkin@linux.intel.com
mainline inclusion from mainline-v5.2-rc1 commit 6cac7866c27418cd784fbb8041c2dddd6d966bc7 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I47H3V CVE: NA
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Now that we have the means to trigger a window switch for the MSU trace store, add a sysfs file to allow triggering it from userspace.
Signed-off-by: Alexander Shishkin alexander.shishkin@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Jackie Liu liuyun01@kylinos.cn Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Reviewed-by: Xie XiuQi xiexiuqi@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- .../testing/sysfs-bus-intel_th-devices-msc | 8 ++++++ drivers/hwtracing/intel_th/msu.c | 28 +++++++++++++++++++ 2 files changed, 36 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-bus-intel_th-devices-msc b/Documentation/ABI/testing/sysfs-bus-intel_th-devices-msc index b940c5d91cf7..f54ae244f3f1 100644 --- a/Documentation/ABI/testing/sysfs-bus-intel_th-devices-msc +++ b/Documentation/ABI/testing/sysfs-bus-intel_th-devices-msc @@ -30,4 +30,12 @@ Description: (RW) Configure MSC buffer size for "single" or "multi" modes. there are no active users and tracing is not enabled) and then allocates a new one.
+What: /sys/bus/intel_th/devices/<intel_th_id>-msc<msc-id>/win_switch +Date: May 2019 +KernelVersion: 5.2 +Contact: Alexander Shishkin alexander.shishkin@linux.intel.com +Description: (RW) Trigger window switch for the MSC's buffer, in + multi-window mode. In "multi" mode, accepts writes of "1", thereby + triggering a window switch for the buffer. Returns an error in any + other operating mode or attempts to write something other than "1".
diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c index bede06c3663a..94ff72cbf0cb 100644 --- a/drivers/hwtracing/intel_th/msu.c +++ b/drivers/hwtracing/intel_th/msu.c @@ -1572,10 +1572,38 @@ nr_pages_store(struct device *dev, struct device_attribute *attr,
static DEVICE_ATTR_RW(nr_pages);
+static ssize_t +win_switch_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t size) +{ + struct msc *msc = dev_get_drvdata(dev); + unsigned long val; + int ret; + + ret = kstrtoul(buf, 10, &val); + if (ret) + return ret; + + if (val != 1) + return -EINVAL; + + mutex_lock(&msc->buf_mutex); + if (msc->mode != MSC_MODE_MULTI) + ret = -ENOTSUPP; + else + ret = intel_th_trace_switch(msc->thdev); + mutex_unlock(&msc->buf_mutex); + + return ret ? ret : size; +} + +static DEVICE_ATTR_WO(win_switch); + static struct attribute *msc_output_attrs[] = { &dev_attr_wrap.attr, &dev_attr_mode.attr, &dev_attr_nr_pages.attr, + &dev_attr_win_switch.attr, NULL, };