[PATCH 3/4] driver: provide sysfs interfaces to access TXT log

From: Qiaowei Ren
Date: Tue May 07 2013 - 03:06:14 EST


These interfaces are located in /sys/devices/platform/intel_txt/log/.

Signed-off-by: Qiaowei Ren <qiaowei.ren@xxxxxxxxx>
Signed-off-by: Xiaoyan Zhang <xiaoyan.zhang@xxxxxxxxx>
Signed-off-by: Gang Wei <gang.wei@xxxxxxxxx>
---
Documentation/ABI/testing/sysfs-platform-intel-txt | 28 +++++
drivers/platform/x86/intel_txt/Makefile | 2 +-
drivers/platform/x86/intel_txt/txt-log.c | 131 ++++++++++++++++++++
drivers/platform/x86/intel_txt/txt-log.h | 27 ++++
drivers/platform/x86/intel_txt/txt-sysfs.c | 5 +
5 files changed, 192 insertions(+), 1 deletion(-)
create mode 100644 drivers/platform/x86/intel_txt/txt-log.c
create mode 100644 drivers/platform/x86/intel_txt/txt-log.h

diff --git a/Documentation/ABI/testing/sysfs-platform-intel-txt b/Documentation/ABI/testing/sysfs-platform-intel-txt
index fa20a9f..ccacac3 100644
--- a/Documentation/ABI/testing/sysfs-platform-intel-txt
+++ b/Documentation/ABI/testing/sysfs-platform-intel-txt
@@ -307,3 +307,31 @@ Contact: "Qiaowei Ren" <qiaowei.ren@xxxxxxxxx>
Description: 0 = Chipset acknowledges that no secrets are in memory.
1 = Chipset believes that secrets are in memory and will
provide reset protection.
+
+What: /sys/devices/platform/intel_txt/log/
+Date: May 2013
+KernelVersion: 3.9
+Contact: "Qiaowei Ren" <qiaowei.ren@xxxxxxxxx>
+Description: The log/ directory exposes tboot log memory.
+
+What: /sys/devices/platform/intel_txt/log/log_header
+Date: May 2013
+KernelVersion: 3.9
+Contact: "Qiaowei Ren" <qiaowei.ren@xxxxxxxxx>
+Description: The "log_header" property will output log header, including
+ max_size and curr_pos.
+
+What: /sys/devices/platform/intel_txt/log/block
+Date: May 2013
+KernelVersion: 3.9
+Contact: "Qiaowei Ren" <qiaowei.ren@xxxxxxxxx>
+Description: The "block" property will dump pure log in block style,
+ 1 page size.
+
+What: /sys/devices/platform/intel_txt/log/block_index
+Date: May 2013
+KernelVersion: 3.9
+Contact: "Qiaowei Ren" <qiaowei.ren@xxxxxxxxx>
+Description: The "block_index" property allows you to set the block
+ index for output.
+
diff --git a/drivers/platform/x86/intel_txt/Makefile b/drivers/platform/x86/intel_txt/Makefile
index 8d5258e..2265370 100644
--- a/drivers/platform/x86/intel_txt/Makefile
+++ b/drivers/platform/x86/intel_txt/Makefile
@@ -2,4 +2,4 @@
# Makefile for the intel TXT drivers.
#
obj-$(CONFIG_INTEL_TXT_DRIVER) += intel_txt.o
-intel_txt-y := txt-sysfs.o txt-config.o
+intel_txt-y := txt-sysfs.o txt-config.o txt-log.o
diff --git a/drivers/platform/x86/intel_txt/txt-log.c b/drivers/platform/x86/intel_txt/txt-log.c
new file mode 100644
index 0000000..3f0f91d
--- /dev/null
+++ b/drivers/platform/x86/intel_txt/txt-log.c
@@ -0,0 +1,131 @@
+/*
+ * txt-log.c
+ *
+ * - log/
+ * log_header -r--r--r-- ; output log header, including max_size and
+ * curr_pos.
+ * block -r--r--r-- ; output pure log in block style, 1 page size.
+ * block_index -rw-rw-r-- ; the block index for output.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/sysfs.h>
+#include <linux/io.h>
+#include <linux/stat.h>
+
+#include "txt-log.h"
+
+static u32 log_block_index;
+
+static int are_uuids_equal(const struct uuid *uuid1,
+ const struct uuid *uuid2)
+{
+ return (memcmp(uuid1, uuid2, sizeof(*uuid1)) == 0) ? 1 : 0;
+}
+
+static struct tboot_log *get_log(void)
+{
+ struct tboot_log *log;
+
+ log = (struct tboot_log *)ioremap_nocache(TBOOT_SERIAL_LOG_ADDR,
+ TBOOT_SERIAL_LOG_SIZE);
+ if (!log)
+ return NULL;
+
+ if (!are_uuids_equal(&(log->uuid),
+ &((struct uuid)TBOOT_LOG_UUID))) {
+ iounmap(log);
+ return NULL;
+ }
+
+ return log;
+}
+
+ssize_t txt_show_log_header(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct tboot_log *log;
+ int ret;
+
+ log = get_log();
+ if (!log)
+ return -EFAULT;
+
+ ret = scnprintf(buf, PAGE_SIZE, "max_size: %x\ncurr_pos: %x\n",
+ log->max_size, log->curr_pos);
+
+ iounmap(log);
+ return ret;
+}
+static DEVICE_ATTR(log_header, S_IRUGO, txt_show_log_header, NULL);
+
+ssize_t txt_show_block(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct tboot_log *log;
+ char *block;
+ int ret;
+
+ log = get_log();
+ if (!log)
+ return -EFAULT;
+
+ block = log->buf + log_block_index * PAGE_SIZE;
+ ret = scnprintf(buf, PAGE_SIZE, "%s\n", block);
+
+ iounmap(log);
+ return ret;
+}
+static DEVICE_ATTR(block, S_IRUGO, txt_show_block, NULL);
+
+ssize_t txt_show_block_index(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ return scnprintf(buf, PAGE_SIZE, "%d\n", log_block_index);
+}
+
+ssize_t txt_store_block_index(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ u32 index;
+ struct tboot_log *log;
+
+ log = get_log();
+ if (!log)
+ return -EFAULT;
+
+ sscanf(buf, "%d", &index);
+ if (index > log->curr_pos / PAGE_SIZE)
+ return -EINVAL;
+ log_block_index = index;
+
+ iounmap(log);
+ return count;
+}
+static DEVICE_ATTR(block_index, S_IRUGO | S_IWUSR | S_IWGRP,
+ txt_show_block_index, txt_store_block_index);
+
+static struct attribute *log_attrs[] = {
+ &dev_attr_log_header.attr,
+ &dev_attr_block.attr,
+ &dev_attr_block_index.attr,
+ NULL,
+};
+
+static struct attribute_group log_attr_grp = {
+ .name = "log",
+ .attrs = log_attrs
+};
+
+int sysfs_create_log(struct kobject *parent)
+{
+ return sysfs_create_group(parent, &log_attr_grp);
+}
+EXPORT_SYMBOL_GPL(sysfs_create_log);
+
+MODULE_LICENSE("GPL");
+
diff --git a/drivers/platform/x86/intel_txt/txt-log.h b/drivers/platform/x86/intel_txt/txt-log.h
new file mode 100644
index 0000000..7eb835e
--- /dev/null
+++ b/drivers/platform/x86/intel_txt/txt-log.h
@@ -0,0 +1,27 @@
+#ifndef __LOG_H__
+#define __LOG_H__
+
+struct uuid {
+ uint32_t data1;
+ uint16_t data2;
+ uint16_t data3;
+ uint16_t data4;
+ uint8_t data5[6];
+} __packed;
+
+struct tboot_log {
+ struct uuid uuid;
+ uint32_t max_size;
+ uint32_t curr_pos;
+ char buf[];
+};
+
+#define TBOOT_LOG_UUID {0xc0192526, 0x6b30, 0x4db4, 0x844c, \
+ {0xa3, 0xe9, 0x53, 0xb8, 0x81, 0x74} }
+#define TBOOT_SERIAL_LOG_ADDR 0x60000
+#define TBOOT_SERIAL_LOG_SIZE 0x08000
+
+extern int sysfs_create_log(struct kobject *parent);
+
+#endif /* __LOG_H__ */
+
diff --git a/drivers/platform/x86/intel_txt/txt-sysfs.c b/drivers/platform/x86/intel_txt/txt-sysfs.c
index 28cc8a2..af556b6 100644
--- a/drivers/platform/x86/intel_txt/txt-sysfs.c
+++ b/drivers/platform/x86/intel_txt/txt-sysfs.c
@@ -16,6 +16,7 @@
#include <linux/sysfs.h>

#include "txt-config.h"
+#include "txt-log.h"

#define DEV_NAME "intel_txt"
static struct platform_device *txt_pdev;
@@ -32,6 +33,10 @@ static int __init txt_sysfs_init(void)
if (retval)
goto err;

+ retval = sysfs_create_log(&txt_pdev->dev.kobj);
+ if (retval)
+ goto err;
+
return 0;

err:
--
1.7.9.5

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