Some utils, like dmidecode and smbios, needs 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. So this patch series adds SMBIOS area to dmi sysfs in order to allow utils in question to work correctly with dmi sysfs.
v1: http://lists.linaro.org/pipermail/linaro-uefi/2015-January/000671.html
v2..v1: firmware: dmi_scan: add symbol to get SMBIOS entry area - used static array instead of remapping base address - removed extern attribute in header
firmware: dmi-sysfs: add SMBIOS entry point area attribute - got SMBIOS table and it's size at init time - moved smbios raw attribute creation after dmi_scan. - read internal array to get SMBIOS table in read funcion - renamed attribute to "smbios_raw_header" instead of smbios_raw
Ivan Khoronzhuk (2): firmware: dmi_scan: add symbol to get SMBIOS entry area firmware: dmi-sysfs: add SMBIOS entry point area attribute
drivers/firmware/dmi-sysfs.c | 42 ++++++++++++++++++++++++++++++++++++++++++ drivers/firmware/dmi_scan.c | 34 ++++++++++++++++++++++++++++++++++ include/linux/dmi.h | 2 ++ 3 files changed, 78 insertions(+)
There are situations when code needs to access SMBIOS entry table area. For example, to pass it via sysfs to userspace when it's not allowed to get SMBIOS info via /dev/mem.
Signed-off-by: Ivan Khoronzhuk ivan.khoronzhuk@linaro.org --- drivers/firmware/dmi_scan.c | 34 ++++++++++++++++++++++++++++++++++ include/linux/dmi.h | 2 ++ 2 files changed, 36 insertions(+)
diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c index 420c8d8..ae9204a 100644 --- a/drivers/firmware/dmi_scan.c +++ b/drivers/firmware/dmi_scan.c @@ -113,6 +113,7 @@ static void dmi_table(u8 *buf, int len, int num, } }
+static unsigned char smbios_header[32]; static phys_addr_t dmi_base; static u16 dmi_len; static u16 dmi_num; @@ -474,6 +475,7 @@ 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); + memcpy(smbios_header, buf, buf[5]);
/* Some BIOS report weird SMBIOS version, fix that up */ switch (smbios_ver) { @@ -505,6 +507,7 @@ static int __init dmi_present(const u8 *buf) pr_info("SMBIOS %d.%d present.\n", dmi_ver >> 8, dmi_ver & 0xFF); } else { + memcpy(smbios_header, buf, 15); dmi_ver = (buf[14] & 0xF0) << 4 | (buf[14] & 0x0F); pr_info("Legacy DMI %d.%d present.\n", @@ -531,6 +534,7 @@ 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); + memcpy(smbios_header, buf, buf[6]);
/* * The 64-bit SMBIOS 3.0 entry point no longer has a field @@ -944,3 +948,33 @@ void dmi_memdev_name(u16 handle, const char **bank, const char **device) } } EXPORT_SYMBOL_GPL(dmi_memdev_name); + +/** + * dmi_get_smbios_entry_area - copy SMBIOS entry point area to array. + * @entry - pointer on array to read area in, current max size is 32 bytes. + * + * returns -ENODATA if table is not available, otherwise returns actual + * size of SMBIOS entry point area. + */ +int dmi_get_smbios_entry_area(char *table) +{ + int size = 0; + + if (!dmi_available) + return -ENODATA; + + if (memcmp(smbios_header, "_SM3_", 5) == 0) + size = smbios_header[6]; + else if (memcmp(smbios_header, "_SM_", 4) == 0) + size = smbios_header[5]; + else if (memcmp(smbios_header, "_DMI_", 5) == 0) + size = 15; + + memcpy(table, smbios_header, size); + + if (!size) + return -ENODATA; + + return size; +} +EXPORT_SYMBOL_GPL(dmi_get_smbios_entry_area); diff --git a/include/linux/dmi.h b/include/linux/dmi.h index f820f0a..4b7f2a3 100644 --- a/include/linux/dmi.h +++ b/include/linux/dmi.h @@ -109,6 +109,7 @@ extern int dmi_walk(void (*decode)(const struct dmi_header *, void *), void *private_data); extern bool dmi_match(enum dmi_field f, const char *str); extern void dmi_memdev_name(u16 handle, const char **bank, const char **device); +int dmi_get_smbios_entry_area(char *table);
#else
@@ -140,6 +141,7 @@ static inline void dmi_memdev_name(u16 handle, const char **bank, const char **device) { } static inline const struct dmi_system_id * dmi_first_match(const struct dmi_system_id *list) { return NULL; } +static int dmi_get_smbios_entry_area(char *table) { return -ENODATA; }
#endif
There are situations when code needs to access SMBIOS entry table area, but cannot use /dev/mem for this. As the table format is consistent only for a version, and can be changed, use binary attribute to give access to raw SMBIOS entry table area.
Signed-off-by: Ivan Khoronzhuk ivan.khoronzhuk@linaro.org --- drivers/firmware/dmi-sysfs.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+)
diff --git a/drivers/firmware/dmi-sysfs.c b/drivers/firmware/dmi-sysfs.c index e0f1cb3..b5c0558 100644 --- a/drivers/firmware/dmi-sysfs.c +++ b/drivers/firmware/dmi-sysfs.c @@ -46,6 +46,8 @@ struct dmi_sysfs_entry { static LIST_HEAD(entry_list); static DEFINE_SPINLOCK(entry_list_lock);
+static unsigned char smbios_raw_header[32]; + /* dmi_sysfs_attribute - Top level attribute. used by all entries. */ struct dmi_sysfs_attribute { struct attribute attr; @@ -646,9 +648,37 @@ static void cleanup_entry_list(void) } }
+static ssize_t smbios_entry_area_raw_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_raw_header[pos], size); + + return size; +} + +static struct bin_attribute smbios_entry_area_raw_attr = { + .read = smbios_entry_area_raw_read, + .attr = {.name = "smbios_raw_header", .mode = 0400}, +}; + static int __init dmi_sysfs_init(void) { int error = -ENOMEM; + int size; int val;
/* Set up our directory */ @@ -669,6 +699,18 @@ static int __init dmi_sysfs_init(void) goto err; }
+ size = dmi_get_smbios_entry_area(smbios_raw_header); + if (size == -ENODATA) { + pr_debug("dmi-sysfs: SMBIOS raw data is not available.\n"); + error = size; + goto err; + } + + /* Create the raw binary file to access the entry area */ + smbios_entry_area_raw_attr.size = size; + if (sysfs_create_bin_file(dmi_kobj, &smbios_entry_area_raw_attr)) + goto err; + pr_debug("dmi-sysfs: loaded.\n");
return 0;
-
Ivan Khoronzhuk