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 subsystem 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 were proposed by Jean Delvare. Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxxxxxxx> --- This patch is logical continuation of "[dmidecode] [Patch v4] firmware: dmi-sysfs: add SMBIOS entry point area attribute" https://lkml.org/lkml/2015/2/4/475 Pay attention that this includes /sys/firmware/dmi for holding tables instead of /sys/firmware/dmi/table as were proposed. Documentation/ABI/testing/sysfs-firmware-dmi | 122 +++------------------ .../ABI/testing/sysfs-firmware-dmi-entries | 110 +++++++++++++++++++ drivers/firmware/dmi-sysfs.c | 12 +- drivers/firmware/dmi_scan.c | 115 +++++++++++++++++-- include/linux/dmi.h | 2 + 5 files changed, 238 insertions(+), 123 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-firmware-dmi-entries diff --git a/Documentation/ABI/testing/sysfs-firmware-dmi b/Documentation/ABI/testing/sysfs-firmware-dmi index c78f9ab..6413128 100644 --- a/Documentation/ABI/testing/sysfs-firmware-dmi +++ b/Documentation/ABI/testing/sysfs-firmware-dmi @@ -1,110 +1,16 @@ What: /sys/firmware/dmi/ -Date: February 2011 -Contact: Mike Waychison <mikew@xxxxxxxxxx> +Date: March 2015 +Contact: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxxxxxxx> Description: - Many machines' firmware (x86 and ia64) export DMI / - SMBIOS tables to the operating system. Getting at this - information is often valuable to userland, especially in - cases where there are OEM extensions used. - - The kernel itself does not rely on the majority of the - information in these tables being correct. It equally - cannot ensure that the data as exported to userland is - without error either. - - DMI is structured as a large table of entries, where - each entry has a common header indicating the type and - length of the entry, as well as a firmware-provided - 'handle' that is supposed to be unique amongst all - entries. - - Some entries are required by the specification, but many - others are optional. In general though, users should - never expect to find a specific entry type on their - system unless they know for certain what their firmware - is doing. Machine to machine experiences will vary. - - Multiple entries of the same type are allowed. In order - to handle these duplicate entry types, each entry is - assigned by the operating system an 'instance', which is - derived from an entry type's ordinal position. That is - to say, if there are 'N' multiple entries with the same type - 'T' in the DMI tables (adjacent or spread apart, it - doesn't matter), they will be represented in sysfs as - entries "T-0" through "T-(N-1)": - - Example entry directories: - - /sys/firmware/dmi/entries/17-0 - /sys/firmware/dmi/entries/17-1 - /sys/firmware/dmi/entries/17-2 - /sys/firmware/dmi/entries/17-3 - ... - - Instance numbers are used in lieu of the firmware - assigned entry handles as the kernel itself makes no - guarantees that handles as exported are unique, and - there are likely firmware images that get this wrong in - the wild. - - Each DMI entry in sysfs has the common header values - exported as attributes: - - handle : The 16bit 'handle' that is assigned to this - entry by the firmware. This handle may be - referred to by other entries. - length : The length of the entry, as presented in the - entry itself. Note that this is _not the - total count of bytes associated with the - entry_. This value represents the length of - the "formatted" portion of the entry. This - "formatted" region is sometimes followed by - the "unformatted" region composed of nul - terminated strings, with termination signalled - by a two nul characters in series. - raw : The raw bytes of the entry. This includes the - "formatted" portion of the entry, the - "unformatted" strings portion of the entry, - and the two terminating nul characters. - type : The type of the entry. This value is the same - as found in the directory name. It indicates - how the rest of the entry should be interpreted. - instance: The instance ordinal of the entry for the - given type. This value is the same as found - in the parent directory name. - position: The ordinal position (zero-based) of the entry - within the entirety of the DMI entry table. - - === Entry Specialization === - - Some entry types may have other information available in - sysfs. Not all types are specialized. - - --- Type 15 - System Event Log --- - - This entry allows the firmware to export a log of - events the system has taken. This information is - typically backed by nvram, but the implementation - details are abstracted by this table. This entry's data - is exported in the directory: - - /sys/firmware/dmi/entries/15-0/system_event_log - - and has the following attributes (documented in the - SMBIOS / DMI specification under "System Event Log (Type 15)": - - area_length - header_start_offset - data_start_offset - access_method - status - change_token - access_method_address - header_format - per_log_type_descriptor_length - type_descriptors_supported_count - - As well, the kernel exports the binary attribute: - - raw_event_log : The raw binary bits of the event log - as described by the DMI entry. + 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. + That's why SMBIOS entry point is represented in dmi sysfs + like a raw attribute and is accessible via + /sys/firmware/dmi/smbios_entry_point. The format of SMBIOS + entry point header can be read in SMBIOS specification. + To simplify access and processing delay in user space, + subsystem provides also raw dmi table under + /sys/firmware/dmi/dmi_table. diff --git a/Documentation/ABI/testing/sysfs-firmware-dmi-entries b/Documentation/ABI/testing/sysfs-firmware-dmi-entries new file mode 100644 index 0000000..c3b4d4c --- /dev/null +++ b/Documentation/ABI/testing/sysfs-firmware-dmi-entries @@ -0,0 +1,110 @@ +What: /sys/firmware/dmi/entries +Date: February 2011 +Contact: Mike Waychison <mikew@xxxxxxxxxx> +Description: + Many machines' firmware (x86 and ia64) export DMI / + SMBIOS tables to the operating system. Getting at this + information is often valuable to userland, especially in + cases where there are OEM extensions used. + + The kernel itself does not rely on the majority of the + information in these tables being correct. It equally + cannot ensure that the data as exported to userland is + without error either. + + DMI is structured as a large table of entries, where + each entry has a common header indicating the type and + length of the entry, as well as a firmware-provided + 'handle' that is supposed to be unique amongst all + entries. + + Some entries are required by the specification, but many + others are optional. In general though, users should + never expect to find a specific entry type on their + system unless they know for certain what their firmware + is doing. Machine to machine experiences will vary. + + Multiple entries of the same type are allowed. In order + to handle these duplicate entry types, each entry is + assigned by the operating system an 'instance', which is + derived from an entry type's ordinal position. That is + to say, if there are 'N' multiple entries with the same type + 'T' in the DMI tables (adjacent or spread apart, it + doesn't matter), they will be represented in sysfs as + entries "T-0" through "T-(N-1)": + + Example entry directories: + + /sys/firmware/dmi/entries/17-0 + /sys/firmware/dmi/entries/17-1 + /sys/firmware/dmi/entries/17-2 + /sys/firmware/dmi/entries/17-3 + ... + + Instance numbers are used in lieu of the firmware + assigned entry handles as the kernel itself makes no + guarantees that handles as exported are unique, and + there are likely firmware images that get this wrong in + the wild. + + Each DMI entry in sysfs has the common header values + exported as attributes: + + handle : The 16bit 'handle' that is assigned to this + entry by the firmware. This handle may be + referred to by other entries. + length : The length of the entry, as presented in the + entry itself. Note that this is _not the + total count of bytes associated with the + entry_. This value represents the length of + the "formatted" portion of the entry. This + "formatted" region is sometimes followed by + the "unformatted" region composed of nul + terminated strings, with termination signalled + by a two nul characters in series. + raw : The raw bytes of the entry. This includes the + "formatted" portion of the entry, the + "unformatted" strings portion of the entry, + and the two terminating nul characters. + type : The type of the entry. This value is the same + as found in the directory name. It indicates + how the rest of the entry should be interpreted. + instance: The instance ordinal of the entry for the + given type. This value is the same as found + in the parent directory name. + position: The ordinal position (zero-based) of the entry + within the entirety of the DMI entry table. + + === Entry Specialization === + + Some entry types may have other information available in + sysfs. Not all types are specialized. + + --- Type 15 - System Event Log --- + + This entry allows the firmware to export a log of + events the system has taken. This information is + typically backed by nvram, but the implementation + details are abstracted by this table. This entry's data + is exported in the directory: + + /sys/firmware/dmi/entries/15-0/system_event_log + + and has the following attributes (documented in the + SMBIOS / DMI specification under "System Event Log (Type 15)": + + area_length + header_start_offset + data_start_offset + access_method + status + change_token + access_method_address + header_format + per_log_type_descriptor_length + type_descriptors_supported_count + + As well, the kernel exports the binary attribute: + + raw_event_log : The raw binary bits of the event log + as described by the DMI entry. diff --git a/drivers/firmware/dmi-sysfs.c b/drivers/firmware/dmi-sysfs.c index e0f1cb3..390067d 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 */ @@ -651,10 +650,10 @@ static int __init dmi_sysfs_init(void) int error = -ENOMEM; int val; - /* Set up our directory */ - dmi_kobj = kobject_create_and_add("dmi", firmware_kobj); - if (!dmi_kobj) - goto err; + if (!dmi_kobj) { + pr_err("dmi-sysfs: dmi subsysterm is absent.\n"); + return -EINVAL; + } dmi_kset = kset_create_and_add("entries", NULL, dmi_kobj); if (!dmi_kset) @@ -675,7 +674,6 @@ static int __init dmi_sysfs_init(void) err: cleanup_entry_list(); kset_unregister(dmi_kset); - kobject_put(dmi_kobj); return error; } @@ -685,8 +683,6 @@ 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 c9cb725..3fca52a 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(): */ @@ -118,6 +124,7 @@ static void dmi_table(u8 *buf, } static phys_addr_t dmi_base; +static u8 *dmi_tb; static int __init dmi_walk_early(void (*decode)(const struct dmi_header *, void *)) @@ -476,6 +483,8 @@ 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) { @@ -508,6 +517,8 @@ static int __init dmi_present(const u8 *buf) dmi_ver >> 8, dmi_ver & 0xFF, (dmi_ver < 0x0300) ? "" : ".x"); } else { + smbios_entry_point_size = 15; + memcpy(smbios_entry_point, buf, 15); dmi_ver = (buf[14] & 0xF0) << 4 | (buf[14] & 0x0F); pr_info("Legacy DMI %d.%d present.\n", @@ -535,6 +546,8 @@ static int __init dmi_smbios3_present(const u8 *buf) dmi_ver &= 0xFFFFFF; 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); /* * The 64-bit SMBIOS 3.0 entry point no longer has a field @@ -638,6 +651,95 @@ void __init dmi_scan_machine(void) dmi_initialized = 1; } +static ssize_t smbios_entry_point_read(struct file *filp, + struct kobject *kobj, + struct bin_attribute *bin_attr, + char *buf, loff_t pos, size_t count) +{ + ssize_t size; + + size = bin_attr->size; + + if (size > pos) + size -= pos; + else + return 0; + + if (count < size) + size = count; + + memcpy(buf, &smbios_entry_point[pos], size); + + return size; +} + +static ssize_t dmi_table_read(struct file *filp, + struct kobject *kobj, + struct bin_attribute *bin_attr, + char *buf, loff_t pos, size_t count) +{ + ssize_t size; + + size = bin_attr->size; + + if (size > pos) + size -= pos; + else + return 0; + + if (count < size) + size = count; + + memcpy(buf, &dmi_tb[pos], size); + + return size; +} + +BIN_ATTR_RO(dmi_table, 0); +BIN_ATTR_RO(smbios_entry_point, 0); + +/* + * Register the dmi subsystem under the firmware subsysterm + */ +static int __init dmisubsys_init(void) +{ + int ret = -ENOMEM; + + if (!smbios_entry_point_size || !dmi_available) { + ret = -EINVAL; + goto err; + } + + /* Set up dmi directory at /sys/firmware/dmi */ + dmi_kobj = kobject_create_and_add("dmi", firmware_kobj); + if (!dmi_kobj) + goto err; + + bin_attr_smbios_entry_point.size = smbios_entry_point_size; + ret = sysfs_create_bin_file(dmi_kobj, &bin_attr_smbios_entry_point); + if (ret) + goto err; + + if (!dmi_tb) { + dmi_tb = dmi_remap(dmi_base, dmi_len); + if (!dmi_tb) + goto err; + } + + bin_attr_dmi_table.size = dmi_len; + ret = sysfs_create_bin_file(dmi_kobj, &bin_attr_dmi_table); + if (ret) + goto err; + + return 0; +err: + pr_err("dmi: Firmware registration failed.\n"); + kobject_del(dmi_kobj); + kobject_put(dmi_kobj); + return ret; +} +subsys_initcall(dmisubsys_init); + /** * dmi_set_dump_stack_arch_desc - set arch description for dump_stack() * @@ -897,18 +999,17 @@ EXPORT_SYMBOL(dmi_get_date); int dmi_walk(void (*decode)(const struct dmi_header *, void *), void *private_data) { - u8 *buf; - if (!dmi_available) return -1; - buf = dmi_remap(dmi_base, dmi_len); - if (buf == NULL) - return -1; + if (!dmi_tb) { + dmi_tb = dmi_remap(dmi_base, dmi_len); + if (!dmi_tb) + return -1; + } - dmi_table(buf, decode, private_data); + dmi_table(dmi_tb, decode, private_data); - dmi_unmap(buf); return 0; } EXPORT_SYMBOL_GPL(dmi_walk); diff --git a/include/linux/dmi.h b/include/linux/dmi.h index f820f0a..316293e 100644 --- a/include/linux/dmi.h +++ b/include/linux/dmi.h @@ -93,6 +93,7 @@ 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); @@ -112,6 +113,7 @@ extern void dmi_memdev_name(u16 handle, const char **bank, const char **device); #else +extern struct kobject *dmi_kobj; static inline int dmi_check_system(const struct dmi_system_id *list) { return 0; } static inline const char * dmi_get_system_info(int field) { return NULL; } static inline const struct dmi_device * dmi_find_device(int type, const char *name, -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
