Version 3.0 of the DTMF SMBIOS reference spec defines a new entry point
type that supports a 64-bit address for the SMBIOS structure table. This
is needed by platforms whose system RAM resides above the 4 GB physical
address boundary, such as upcoming 64-bit ARM platforms.
This is a preliminary RFC implementation, as there is no definition available
yet for SMBIOS3_TABLE_GUID, which the (currently still in draft) SMBIOS v3.0
spec refers to.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
drivers/firmware/dmi_scan.c | 70 +++++++++++++++++++++++++++++++++++++++++++--
drivers/firmware/efi/efi.c | 4 +++
include/linux/efi.h | 6 +++-
3 files changed, 77 insertions(+), 3 deletions(-)
diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 17afc51f3054..6e33072c3ac3 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -93,6 +93,12 @@ static void dmi_table(u8 *buf, int len, int num,
const struct dmi_header *dm = (const struct dmi_header *)data;
/*
+ * 7.45 End-of-Table (Type 127) [SMBIOS reference spec v3.0.0]
+ */
+ if (dm->type == 127)
+ break;
+
+ /*
* We want to know the total length (formatted area and
* strings) before decoding to make sure we won't run off the
* table in dmi_decode or dmi_string
@@ -107,7 +113,7 @@ static void dmi_table(u8 *buf, int len, int num,
}
}
-static u32 dmi_base;
+static phys_addr_t dmi_base;
static u16 dmi_len;
static u16 dmi_num;
@@ -514,12 +520,72 @@ static int __init dmi_present(const u8 *buf)
return 1;
}
+/*
+ * Check for the SMBIOS 3.0 64-bit entry point signature. Unlike the legacy
+ * 32-bit entry point, there is no embedded DMI header (_DMI_) in here.
+ */
+static int __init dmi_smbios3_present(const u8 *buf)
+{
+ if (memcmp(buf, "_SM3_", 5) == 0 &&
+ buf[6] < 32 && dmi_checksum(buf, buf[6])) {
+ dmi_ver = get_unaligned_be16(buf + 7);
+ dmi_len = get_unaligned_le32(buf + 12);
+ dmi_base = get_unaligned_le64(buf + 16);
+
+ /*
+ * The 64-bit SMBIOS 3.0 entry point no longer has a field
+ * containing the number of structures present in the table.
+ * Instead, it defines the table size as a maximum size, and
+ * relies on the end-of-table structure type (#127) to be used
+ * to signal the end of the table.
+ * So let's define dmi_num as an upper bound as well: each
+ * structure has a 4 byte header, so dmi_len / 4 is an upper
+ * bound of the number of structures in the table.
+ */
+ dmi_num = dmi_len / 4;
+
+ if (dmi_walk_early(dmi_decode) == 0) {
+ pr_info("SMBIOS %d.%d present.\n",
+ dmi_ver >> 8, dmi_ver & 0xFF);
+ dmi_format_ids(dmi_ids_string, sizeof(dmi_ids_string));
+ printk(KERN_DEBUG "DMI: %s\n", dmi_ids_string);
+ return 0;
+ }
+ }
+ return 1;
+}
+
void __init dmi_scan_machine(void)
{
char __iomem *p, *q;
char buf[32];
if (efi_enabled(EFI_CONFIG_TABLES)) {
+ /*
+ * According to the DTMF SMBIOS reference spec v3.0.0, it is
+ * allowed to define both the 64-bit entry point (smbios3) and
+ * the 32-bit entry point (smbios), in which case they should
+ * either both point to the same SMBIOS structure table, or the
+ * table pointed to by the 64-bit entry point should contain a
+ * superset of the table contents pointed to by the 32-bit entry
+ * point (section 5.2)
+ * This implies that the 64-bit entry point should have
+ * precedence if it is defined and supported by the OS. If we
+ * have the 64-bit entry point, but fail to decode it, fall
+ * back to the legacy one (if available)
+ */
+ if (efi.smbios3 != EFI_INVALID_TABLE_ADDR) {
+ p = dmi_early_remap(efi.smbios3, 32);
+ if (p == NULL)
+ goto error;
+ memcpy_fromio(buf, p, 32);
+ dmi_early_unmap(p, 32);
+
+ if (!dmi_smbios3_present(buf)) {
+ dmi_available = 1;
+ goto out;
+ }
+ }
if (efi.smbios == EFI_INVALID_TABLE_ADDR)
goto error;
@@ -552,7 +618,7 @@ void __init dmi_scan_machine(void)
memset(buf, 0, 16);
for (q = p; q < p + 0x10000; q += 16) {
memcpy_fromio(buf + 16, q, 16);
- if (!dmi_present(buf)) {
+ if (!dmi_smbios3_present(buf) || !dmi_present(buf)) {
dmi_available = 1;
dmi_early_unmap(p, 0x10000);
goto out;
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 8590099ac148..9035c1b74d58 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -30,6 +30,7 @@ struct efi __read_mostly efi = {
.acpi = EFI_INVALID_TABLE_ADDR,
.acpi20 = EFI_INVALID_TABLE_ADDR,
.smbios = EFI_INVALID_TABLE_ADDR,
+ .smbios3 = EFI_INVALID_TABLE_ADDR,
.sal_systab = EFI_INVALID_TABLE_ADDR,
.boot_info = EFI_INVALID_TABLE_ADDR,
.hcdp = EFI_INVALID_TABLE_ADDR,
@@ -86,6 +87,8 @@ static ssize_t systab_show(struct kobject *kobj,
str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
if (efi.smbios != EFI_INVALID_TABLE_ADDR)
str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
+ if (efi.smbios3 != EFI_INVALID_TABLE_ADDR)
+ str += sprintf(str, "SMBIOS3=0x%lx\n", efi.smbios3);
if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
@@ -260,6 +263,7 @@ static __initdata efi_config_table_type_t common_tables[] = {
{MPS_TABLE_GUID, "MPS", &efi.mps},
{SAL_SYSTEM_TABLE_GUID, "SALsystab", &efi.sal_systab},
{SMBIOS_TABLE_GUID, "SMBIOS", &efi.smbios},
+ {SMBIOS3_TABLE_GUID, "SMBIOS 3.0", &efi.smbios3},
{UGA_IO_PROTOCOL_GUID, "UGA", &efi.uga},
{NULL_GUID, NULL, NULL},
};
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 0949f9c7e872..7704f587fc15 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -547,6 +547,9 @@ void efi_native_runtime_setup(void);
#define SMBIOS_TABLE_GUID \
EFI_GUID( 0xeb9d2d31, 0x2d88, 0x11d3, 0x9a, 0x16, 0x0, 0x90, 0x27, 0x3f, 0xc1, 0x4d )
+#define SMBIOS3_TABLE_GUID \
+ EFI_GUID( 0x00000000, 0x0000, 0x0000, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 )
+
#define SAL_SYSTEM_TABLE_GUID \
EFI_GUID( 0xeb9d2d32, 0x2d88, 0x11d3, 0x9a, 0x16, 0x0, 0x90, 0x27, 0x3f, 0xc1, 0x4d )
@@ -810,7 +813,8 @@ extern struct efi {
unsigned long mps; /* MPS table */
unsigned long acpi; /* ACPI table (IA64 ext 0.71) */
unsigned long acpi20; /* ACPI table (ACPI 2.0) */
- unsigned long smbios; /* SM BIOS table */
+ unsigned long smbios; /* SM BIOS table (32 bit entry point) */
+ unsigned long smbios3; /* SM BIOS table (64 bit entry point) */
unsigned long sal_systab; /* SAL system table */
unsigned long boot_info; /* boot info table */
unsigned long hcdp; /* HCDP table */
--
1.8.3.2
--
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