[Patch v3 0/3] firmware: dmi_scan: add SBMIOS entry point and DMI tables

[Patch v3 0/3] firmware: dmi_scan: add SBMIOS entry point and DMI tables

[Ivan Khoronzhuk]

This series adds SMBIOS entry point table and DMI table under
/sys/firmware/dmi/tables in order to use as an alternative to utilities
reading them from /dev/mem.

Based on linux next + 2 patches from Jean Delvare.
The patches can be obtained with links:

http://jdelvare.nerim.net/devel/linux-3/jdelvare-dmi/firmware-dmi-03-simplify-displayed-version.patch
http://jdelvare.nerim.net/devel/linux-3/jdelvare-dmi/firmware-dmi-04-fix-product-uuid.patch

Link on V2:
https://lkml.org/lkml/2015/4/20/218

Changes since V2
	- use more labels in error path

Changes since V1
	- correct error path in dmi-sysfs
	- don't use globally dmi_table var
	- use "DMI" in attribute name
	- correct error path in dmi_init
	- leave dmi_kobj even in case of error
	- include linux/kobject.h in header

Ivan Khoronzhuk (3):
  firmware: dmi_scan: rename dmi_table to dmi_decode_table
  firmware: dmi_scan: add SBMIOS entry and DMI tables
  Documentation: ABI: sysfs-firmware-dmi: add -entries suffix to file
    name

 ...sfs-firmware-dmi => sysfs-firmware-dmi-entries} |  2 +-
 .../ABI/testing/sysfs-firmware-dmi-tables          | 22 ++++++
 drivers/firmware/dmi-sysfs.c                       | 17 ++---
 drivers/firmware/dmi_scan.c                        | 88 ++++++++++++++++++++--
 include/linux/dmi.h                                |  2 +
 5 files changed, 116 insertions(+), 15 deletions(-)
 rename Documentation/ABI/testing/{sysfs-firmware-dmi => sysfs-firmware-dmi-entries} (99%)
 create mode 100644 Documentation/ABI/testing/sysfs-firmware-dmi-tables

-- 
1.9.1

[Patch v3 1/3] firmware: dmi_scan: rename dmi_table to dmi_decode_table

[Ivan Khoronzhuk]

The "dmi_table" function looks like data instance, but it does DMI
table decode. This patch renames it to "dmi_decode_table" name as
more appropriate. That allows us to use "dmi_table" name for correct
purposes.

Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@globallogic.com>
---
 drivers/firmware/dmi_scan.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 97b1616..a864a6b 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -80,9 +80,9 @@ static const char * __init dmi_string(const struct dmi_header *dm, u8 s)
  *	We have to be cautious here. We have seen BIOSes with DMI pointers
  *	pointing to completely the wrong place for example
  */
-static void dmi_table(u8 *buf,
-		      void (*decode)(const struct dmi_header *, void *),
-		      void *private_data)
+static void dmi_decode_table(u8 *buf,
+			     void (*decode)(const struct dmi_header *, void *),
+			     void *private_data)
 {
 	u8 *data = buf;
 	int i = 0;
@@ -130,7 +130,7 @@ static int __init dmi_walk_early(void (*decode)(const struct dmi_header *,
 	if (buf == NULL)
 		return -1;
 
-	dmi_table(buf, decode, NULL);
+	dmi_decode_table(buf, decode, NULL);
 
 	add_device_randomness(buf, dmi_len);
 
@@ -897,7 +897,7 @@ int dmi_walk(void (*decode)(const struct dmi_header *, void *),
 	if (buf == NULL)
 		return -1;
 
-	dmi_table(buf, decode, private_data);
+	dmi_decode_table(buf, decode, private_data);
 
 	dmi_unmap(buf);
 	return 0;
-- 
1.9.1

[Patch v3 1/3] firmware: dmi_scan: rename dmi_table to dmi_decode_table

[Ivan Khoronzhuk]

The "dmi_table" function looks like data instance, but it does DMI
table decode. This patch renames it to "dmi_decode_table" name as
more appropriate. That allows us to use "dmi_table" name for correct
purposes.

Reviewed-by: Jean Delvare <jdelvare-l3A5Bk7waGM@public.gmane.org>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk-hExfYMNmJl/Cnp4W7fqMDg@public.gmane.org>
---
 drivers/firmware/dmi_scan.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 97b1616..a864a6b 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -80,9 +80,9 @@ static const char * __init dmi_string(const struct dmi_header *dm, u8 s)
  *	We have to be cautious here. We have seen BIOSes with DMI pointers
  *	pointing to completely the wrong place for example
  */
-static void dmi_table(u8 *buf,
-		      void (*decode)(const struct dmi_header *, void *),
-		      void *private_data)
+static void dmi_decode_table(u8 *buf,
+			     void (*decode)(const struct dmi_header *, void *),
+			     void *private_data)
 {
 	u8 *data = buf;
 	int i = 0;
@@ -130,7 +130,7 @@ static int __init dmi_walk_early(void (*decode)(const struct dmi_header *,
 	if (buf == NULL)
 		return -1;
 
-	dmi_table(buf, decode, NULL);
+	dmi_decode_table(buf, decode, NULL);
 
 	add_device_randomness(buf, dmi_len);
 
@@ -897,7 +897,7 @@ int dmi_walk(void (*decode)(const struct dmi_header *, void *),
 	if (buf == NULL)
 		return -1;
 
-	dmi_table(buf, decode, private_data);
+	dmi_decode_table(buf, decode, private_data);
 
 	dmi_unmap(buf);
 	return 0;
-- 
1.9.1

[Patch v3 2/3] firmware: dmi_scan: add SBMIOS entry and DMI tables

[Ivan Khoronzhuk]

Some utils, like dmidecode and smbios, need to access SMBIOS entry
table area in order to get information like SMBIOS version, size, etc.
Currently it's done via /dev/mem. But for situation when /dev/mem
usage is disabled, the utils have to use dmi sysfs instead, which
doesn't represent SMBIOS entry and adds code/delay redundancy when direct
access for table is needed.

So this patch creates dmi/tables and adds SMBIOS entry point to allow
utils in question to work correctly without /dev/mem. Also patch adds
raw dmi table to simplify dmi table processing in user space, as
proposed by Jean Delvare.

Tested-by: Roy Franz <roy.franz@linaro.org>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@globallogic.com>
---
 .../ABI/testing/sysfs-firmware-dmi-tables          | 22 ++++++
 drivers/firmware/dmi-sysfs.c                       | 17 +++--
 drivers/firmware/dmi_scan.c                        | 78 ++++++++++++++++++++++
 include/linux/dmi.h                                |  2 +
 4 files changed, 110 insertions(+), 9 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-firmware-dmi-tables

diff --git a/Documentation/ABI/testing/sysfs-firmware-dmi-tables b/Documentation/ABI/testing/sysfs-firmware-dmi-tables
new file mode 100644
index 0000000..ff3cac8
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-firmware-dmi-tables
@@ -0,0 +1,22 @@
+What:		/sys/firmware/dmi/tables/
+Date:		April 2015
+Contact:	Ivan Khoronzhuk <ivan.khoronzhuk@globallogic.com>
+Description:
+		The firmware provides DMI structures as a packed list of
+		data referenced by a SMBIOS table entry point. The SMBIOS
+		entry point contains general information, like SMBIOS
+		version, DMI table size, etc. The structure, content and
+		size of SMBIOS entry point is dependent on SMBIOS version.
+		The format of SMBIOS entry point and DMI structures
+		can be read in SMBIOS specification.
+
+		The dmi/tables provides raw SMBIOS entry point and DMI tables
+		through sysfs as an alternative to utilities reading them
+		from /dev/mem. The raw SMBIOS entry point and DMI table are
+		presented as binary attributes and are accessible via:
+
+		/sys/firmware/dmi/tables/smbios_entry_point
+		/sys/firmware/dmi/tables/DMI
+
+		The complete DMI information can be obtained using these two
+		tables.
diff --git a/drivers/firmware/dmi-sysfs.c b/drivers/firmware/dmi-sysfs.c
index e0f1cb3..ef76e5e 100644
--- a/drivers/firmware/dmi-sysfs.c
+++ b/drivers/firmware/dmi-sysfs.c
@@ -566,7 +566,6 @@ static struct kobj_type dmi_sysfs_entry_ktype = {
 	.default_attrs = dmi_sysfs_entry_attrs,
 };
 
-static struct kobject *dmi_kobj;
 static struct kset *dmi_kset;
 
 /* Global count of all instances seen.  Only for setup */
@@ -648,17 +647,20 @@ static void cleanup_entry_list(void)
 
 static int __init dmi_sysfs_init(void)
 {
-	int error = -ENOMEM;
+	int error;
 	int val;
 
-	/* Set up our directory */
-	dmi_kobj = kobject_create_and_add("dmi", firmware_kobj);
-	if (!dmi_kobj)
+	if (!dmi_kobj) {
+		pr_err("dmi-sysfs: dmi entry is absent.\n");
+		error = -ENODATA;
 		goto err;
+	}
 
 	dmi_kset = kset_create_and_add("entries", NULL, dmi_kobj);
-	if (!dmi_kset)
+	if (!dmi_kset) {
+		error = -ENOMEM;
 		goto err;
+	}
 
 	val = 0;
 	error = dmi_walk(dmi_sysfs_register_handle, &val);
@@ -675,7 +677,6 @@ static int __init dmi_sysfs_init(void)
 err:
 	cleanup_entry_list();
 	kset_unregister(dmi_kset);
-	kobject_put(dmi_kobj);
 	return error;
 }
 
@@ -685,8 +686,6 @@ static void __exit dmi_sysfs_exit(void)
 	pr_debug("dmi-sysfs: unloading.\n");
 	cleanup_entry_list();
 	kset_unregister(dmi_kset);
-	kobject_del(dmi_kobj);
-	kobject_put(dmi_kobj);
 }
 
 module_init(dmi_sysfs_init);
diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index a864a6b..389f8e9 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -10,6 +10,9 @@
 #include <asm/dmi.h>
 #include <asm/unaligned.h>
 
+struct kobject *dmi_kobj;
+EXPORT_SYMBOL_GPL(dmi_kobj);
+
 /*
  * DMI stands for "Desktop Management Interface".  It is part
  * of and an antecedent to, SMBIOS, which stands for System
@@ -20,6 +23,9 @@ static const char dmi_empty_string[] = "        ";
 static u32 dmi_ver __initdata;
 static u32 dmi_len;
 static u16 dmi_num;
+static u8 smbios_entry_point[32];
+static int smbios_entry_point_size;
+
 /*
  * Catch too early calls to dmi_check_system():
  */
@@ -478,6 +484,8 @@ static int __init dmi_present(const u8 *buf)
 	if (memcmp(buf, "_SM_", 4) == 0 &&
 	    buf[5] < 32 && dmi_checksum(buf, buf[5])) {
 		smbios_ver = get_unaligned_be16(buf + 6);
+		smbios_entry_point_size = buf[5];
+		memcpy(smbios_entry_point, buf, smbios_entry_point_size);
 
 		/* Some BIOS report weird SMBIOS version, fix that up */
 		switch (smbios_ver) {
@@ -512,6 +520,9 @@ static int __init dmi_present(const u8 *buf)
 				pr_info("SMBIOS %d.%d present.\n",
 				       dmi_ver >> 8, dmi_ver & 0xFF);
 			} else {
+				smbios_entry_point_size = 15;
+				memcpy(smbios_entry_point, buf,
+				       smbios_entry_point_size);
 				pr_info("Legacy DMI %d.%d present.\n",
 				       dmi_ver >> 8, dmi_ver & 0xFF);
 			}
@@ -538,6 +549,8 @@ static int __init dmi_smbios3_present(const u8 *buf)
 		dmi_num = 0;			/* No longer specified */
 		dmi_len = get_unaligned_le32(buf + 12);
 		dmi_base = get_unaligned_le64(buf + 16);
+		smbios_entry_point_size = buf[6];
+		memcpy(smbios_entry_point, buf, smbios_entry_point_size);
 
 		if (dmi_walk_early(dmi_decode) == 0) {
 			pr_info("SMBIOS %d.%d.%d present.\n",
@@ -629,6 +642,71 @@ void __init dmi_scan_machine(void)
 	dmi_initialized = 1;
 }
 
+static ssize_t raw_table_read(struct file *file, struct kobject *kobj,
+			      struct bin_attribute *attr, char *buf,
+			      loff_t pos, size_t count)
+{
+	memcpy(buf, attr->private + pos, count);
+	return count;
+}
+
+static BIN_ATTR(smbios_entry_point, S_IRUSR, raw_table_read, NULL, 0);
+static BIN_ATTR(DMI, S_IRUSR, raw_table_read, NULL, 0);
+
+static int __init dmi_init(void)
+{
+	u8 *dmi_table;
+	int ret = -ENOMEM;
+	struct kobject *tables_kobj;
+
+	if (!dmi_available) {
+		ret = -ENODATA;
+		goto err;
+	}
+
+	/*
+	 * Set up dmi directory at /sys/firmware/dmi. This entry should stay
+	 * even after farther error, as it can be used by other modules like
+	 * dmi-sysfs.
+	 */
+	dmi_kobj = kobject_create_and_add("dmi", firmware_kobj);
+	if (!dmi_kobj)
+		goto err;
+
+	tables_kobj = kobject_create_and_add("tables", dmi_kobj);
+	if (!tables_kobj)
+		goto err;
+
+	dmi_table = dmi_remap(dmi_base, dmi_len);
+	if (!dmi_table)
+		goto err_tables;
+
+	bin_attr_smbios_entry_point.size = smbios_entry_point_size;
+	bin_attr_smbios_entry_point.private = smbios_entry_point;
+	ret = sysfs_create_bin_file(tables_kobj, &bin_attr_smbios_entry_point);
+	if (ret)
+		goto err_remap;
+
+	bin_attr_DMI.size = dmi_len;
+	bin_attr_DMI.private = dmi_table;
+	ret = sysfs_create_bin_file(tables_kobj, &bin_attr_DMI);
+	if (!ret)
+		return 0;
+
+	sysfs_remove_bin_file(tables_kobj,
+			      &bin_attr_smbios_entry_point);
+err_remap:
+	dmi_unmap(dmi_table);
+err_tables:
+	kobject_del(tables_kobj);
+	kobject_put(tables_kobj);
+err:
+	pr_err("dmi: Firmware registration failed.\n");
+
+	return ret;
+}
+subsys_initcall(dmi_init);
+
 /**
  * dmi_set_dump_stack_arch_desc - set arch description for dump_stack()
  *
diff --git a/include/linux/dmi.h b/include/linux/dmi.h
index f820f0a..2f9f988 100644
--- a/include/linux/dmi.h
+++ b/include/linux/dmi.h
@@ -2,6 +2,7 @@
 #define __DMI_H__
 
 #include <linux/list.h>
+#include <linux/kobject.h>
 #include <linux/mod_devicetable.h>
 
 /* enum dmi_field is in mod_devicetable.h */
@@ -93,6 +94,7 @@ struct dmi_dev_onboard {
 	int devfn;
 };
 
+extern struct kobject *dmi_kobj;
 extern int dmi_check_system(const struct dmi_system_id *list);
 const struct dmi_system_id *dmi_first_match(const struct dmi_system_id *list);
 extern const char * dmi_get_system_info(int field);
-- 
1.9.1

[Patch v3 3/3] Documentation: ABI: sysfs-firmware-dmi: add -entries suffix to file name

[Ivan Khoronzhuk]

The dmi-sysfs module adds DMI table structures entries under
/sys/firmware/dmi/entries only, so rename documentation file to
sysfs-firmware-dmi-entries as more appropriate. Without renaming it's
confusing to differ this from sysfs-firmware-dmi-tables that adds raw
DMI table and actually adds "dmi" kobject.

Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@globallogic.com>
---
 .../ABI/testing/{sysfs-firmware-dmi => sysfs-firmware-dmi-entries}      | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
 rename Documentation/ABI/testing/{sysfs-firmware-dmi => sysfs-firmware-dmi-entries} (99%)

diff --git a/Documentation/ABI/testing/sysfs-firmware-dmi b/Documentation/ABI/testing/sysfs-firmware-dmi-entries
similarity index 99%
rename from Documentation/ABI/testing/sysfs-firmware-dmi
rename to Documentation/ABI/testing/sysfs-firmware-dmi-entries
index c78f9ab..210ad44 100644
--- a/Documentation/ABI/testing/sysfs-firmware-dmi
+++ b/Documentation/ABI/testing/sysfs-firmware-dmi-entries
@@ -1,4 +1,4 @@
-What:		/sys/firmware/dmi/
+What:		/sys/firmware/dmi/entries/
 Date:		February 2011
 Contact:	Mike Waychison <mikew@google.com>
 Description:
-- 
1.9.1