| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20190408210947.150095-1-twawrzynczak@chromium.org>
Date: Mon, 8 Apr 2019 15:09:47 -0600
From: Tim Wawrzynczak <twawrzynczak@...omium.org>
To: linux-kernel@...r.kernel.org
Cc: Benson Leung <bleung@...omium.org>,
Enric Balletbo i Serra <enric.balletbo@...labora.com>,
Guenter Roeck <groeck@...omium.org>,
Tim Wawrzynczak <twawrzynczak@...omium.org>
Subject: [PATCH v4] platform/chrome: mfd/cros_ec_debugfs: Add debugfs entry to retrieve EC uptime.
The new debugfs entry 'uptime' is being made available to userspace so that
a userspace daemon can synchronize EC logs with host time.
Signed-off-by: Tim Wawrzynczak <twawrzynczak@...omium.org>
---
Enric, AFAIK only the cros_ec supports the 'uptime' command for now.
And yes, the file does need to be seekable; the userspace daemon that
consumes the file keeps the file open and seeks back to the beginning
to get the latest uptime value.
Based on your second response to v3, I kept the separate 'create_uptime'
function b/c of the logic for checking support for the uptime command.
Let me know if you'd like me to move all of that logic into _probe.
Changelist from v3:
1) Don't check return values of debugfs_* functions.
2) Only expose 'uptime' file if EC supports it.
---
Documentation/ABI/testing/debugfs-cros-ec | 10 +++
drivers/platform/chrome/cros_ec_debugfs.c | 78 +++++++++++++++++++++++
2 files changed, 88 insertions(+)
create mode 100644 Documentation/ABI/testing/debugfs-cros-ec
diff --git a/Documentation/ABI/testing/debugfs-cros-ec b/Documentation/ABI/testing/debugfs-cros-ec
new file mode 100644
index 000000000000..24b781c67a4c
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-cros-ec
@@ -0,0 +1,10 @@
+What: /sys/kernel/debug/cros_ec/uptime
+Date: March 2019
+KernelVersion: 5.1
+Description:
+ Read-only.
+ Reads the EC's current uptime information
+ (using EC_CMD_GET_UPTIME_INFO) and prints
+ time_since_ec_boot_ms into the file.
+ This is used for synchronizing AP host time
+ with the cros_ec log.
diff --git a/drivers/platform/chrome/cros_ec_debugfs.c b/drivers/platform/chrome/cros_ec_debugfs.c
index 71308766e891..226545a2150b 100644
--- a/drivers/platform/chrome/cros_ec_debugfs.c
+++ b/drivers/platform/chrome/cros_ec_debugfs.c
@@ -201,6 +201,50 @@ static int cros_ec_console_log_release(struct inode *inode, struct file *file)
return 0;
}
+static int cros_ec_get_uptime(struct cros_ec_device *ec_dev, u32 *uptime)
+{
+ struct {
+ struct cros_ec_command msg;
+ struct ec_response_uptime_info resp;
+ } __packed ec_buf;
+ struct ec_response_uptime_info *resp;
+ struct cros_ec_command *msg;
+
+ msg = &ec_buf.msg;
+ resp = (struct ec_response_uptime_info *)msg->data;
+
+ msg->command = EC_CMD_GET_UPTIME_INFO;
+ msg->version = 0;
+ msg->insize = sizeof(*resp);
+ msg->outsize = 0;
+
+ ret = cros_ec_cmd_xfer_status(ec_dev, msg);
+ if (ret < 0)
+ return ret;
+
+ *uptime = resp->time_since_ec_boot_ms;
+ return 0;
+}
+
+static ssize_t cros_ec_uptime_read(struct file *file,
+ char __user *user_buf,
+ size_t count,
+ loff_t *ppos)
+{
+ struct cros_ec_debugfs *debug_info = file->private_data;
+ struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
+ char read_buf[32];
+ int ret;
+ u32 uptime;
+
+ ret = cros_ec_get_uptime(ec_dev, &uptime);
+ if (ret < 0)
+ return ret;
+
+ ret = scnprintf(read_buf, sizeof(read_buf), "%u\n", uptime);
+ return simple_read_from_buffer(user_buf, count, ppos, read_buf, ret);
+}
+
static ssize_t cros_ec_pdinfo_read(struct file *file,
char __user *user_buf,
size_t count,
@@ -269,6 +313,13 @@ const struct file_operations cros_ec_pdinfo_fops = {
.llseek = default_llseek,
};
+const struct file_operations cros_ec_uptime_fops = {
+ .owner = THIS_MODULE,
+ .open = simple_open,
+ .read = cros_ec_uptime_read,
+ .llseek = default_llseek,
+};
+
static int ec_read_version_supported(struct cros_ec_dev *ec)
{
struct ec_params_get_cmd_versions_v1 *params;
@@ -413,6 +464,29 @@ static int cros_ec_create_pdinfo(struct cros_ec_debugfs *debug_info)
return 0;
}
+static int cros_ec_create_uptime(struct cros_ec_debugfs *debug_info)
+{
+ struct cros_ec_debugfs *debug_info = file->private_data;
+ struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
+ u32 uptime;
+ int ret;
+
+ /*
+ * If the EC does not support the uptime command, which is
+ * indicated by xfer_status() returning -EINVAL, then no
+ * debugfs entry will be created.
+ */
+ ret = cros_ec_get_uptime(ec_dev, &uptime);
+
+ if (ret == -EINVAL)
+ return supported;
+
+ debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
+ &cros_ec_uptime_fops);
+
+ return 0;
+}
+
static int cros_ec_debugfs_probe(struct platform_device *pd)
{
struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
@@ -442,6 +516,10 @@ static int cros_ec_debugfs_probe(struct platform_device *pd)
if (ret)
goto remove_log;
+ ret = cros_ec_create_uptime(debug_info);
+ if (ret)
+ goto remove_log;
+
ec->debug_info = debug_info;
dev_set_drvdata(&pd->dev, ec);
--
2.20.1
Powered by blists - more mailing lists