[smbios] Add support for the 64-bit SMBIOS3 entry point

Support UEFI systems that provide only 64-bit versions of the SMBIOS
entry point.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/ipxe/smbios.h

@@ -31,15 +31,20 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 /* Include all architecture-dependent SMBIOS API headers */
 #include <bits/smbios.h>
 
-/** Signature for SMBIOS entry point */
+/** Signature for 32-bit SMBIOS entry point */
 #define SMBIOS_SIGNATURE \
         ( ( '_' << 0 ) + ( 'S' << 8 ) + ( 'M' << 16 ) + ( '_' << 24 ) )
 
+/** Signature for 64-bit SMBIOS entry point */
+#define SMBIOS3_SIGNATURE \
+        ( ( '_' << 0 ) + ( 'S' << 8 ) + ( 'M' << 16 ) + ( '3' << 24 ) )
+
 /**
- * SMBIOS entry point
+ * SMBIOS 32-bit entry point
  *
- * This is the single table which describes the list of SMBIOS
+ * This is the 32-bit version of the table which describes the list of
- * structures.  It is located by scanning through the BIOS segment.
+ * SMBIOS structures.  It may be located by scanning through the BIOS
+ * segment or via an EFI configuration table.
  */
 struct smbios_entry {
 	/** Signature
@@ -75,6 +80,41 @@ struct smbios_entry {
 	uint8_t bcd_revision;
 } __attribute__ (( packed ));
 
+/**
+ * SMBIOS 64-bit entry point
+ *
+ * This is the 64-bit version of the table which describes the list of
+ * SMBIOS structures.  It may be located by scanning through the BIOS
+ * segment or via an EFI configuration table.
+ */
+struct smbios3_entry {
+	/** Signature
+	 *
+	 * Must be equal to SMBIOS3_SIGNATURE
+	 */
+	uint32_t signature;
+	/** Signature extra byte */
+	uint8_t extra;
+	/** Checksum */
+	uint8_t checksum;
+	/** Length */
+	uint8_t len;
+	/** Major version */
+	uint8_t major;
+	/** Minor version */
+	uint8_t minor;
+	/** Documentation revision */
+	uint8_t docrev;
+	/** Entry point revision */
+	uint8_t revision;
+	/** Reserved */
+	uint8_t reserved;
+	/** Structure table length */
+	uint32_t smbios_len;
+	/** Structure table address */
+	uint64_t smbios_address;
+} __attribute__ (( packed ));
+
 /** An SMBIOS structure header */
 struct smbios_header {
 	/** Type */
@@ -155,6 +195,9 @@ struct smbios_enclosure_information {
 /** SMBIOS OEM strings structure type */
 #define SMBIOS_TYPE_OEM_STRINGS 11
 
+/** SMBIOS end of table type */
+#define SMBIOS_TYPE_END 127
+
 /**
  * SMBIOS entry point descriptor
  *

src/interface/efi/efi_smbios.c

@@ -34,6 +34,10 @@ FILE_LICENCE ( GPL2_OR_LATER );
 static struct smbios_entry *smbios_entry;
 EFI_USE_TABLE ( SMBIOS_TABLE, &smbios_entry, 0 );
 
+/** SMBIOS configuration table */
+static struct smbios3_entry *smbios3_entry;
+EFI_USE_TABLE ( SMBIOS3_TABLE, &smbios3_entry, 0 );
+
 /**
  * Find SMBIOS
  *
@@ -42,26 +46,34 @@ EFI_USE_TABLE ( SMBIOS_TABLE, &smbios_entry, 0 );
  */
 static int efi_find_smbios ( struct smbios *smbios ) {
 
-	if ( ! smbios_entry ) {
+	/* Use 64-bit table if present */
-		DBG ( "No SMBIOS table provided\n" );
+	if ( smbios3_entry && ( smbios3_entry->signature == SMBIOS3_SIGNATURE ) ) {
-		return -ENODEV;
+		smbios->address = phys_to_user ( smbios3_entry->smbios_address );
+		smbios->len = smbios3_entry->smbios_len;
+		smbios->count = 0;
+		smbios->version =
+			SMBIOS_VERSION ( smbios3_entry->major, smbios3_entry->minor );
+		DBG ( "Found 64-bit SMBIOS v%d.%d entry point at %p (%lx+%zx)\n",
+		      smbios3_entry->major, smbios3_entry->minor, smbios3_entry,
+		      user_to_phys ( smbios->address, 0 ), smbios->len );
+		return 0;
 	}
 
-	if ( smbios_entry->signature != SMBIOS_SIGNATURE ) {
+	/* Otherwise, use 32-bit table if present */
-		DBG ( "Invalid SMBIOS signature\n" );
+	if ( smbios_entry && ( smbios_entry->signature == SMBIOS_SIGNATURE ) ) {
-		return -ENODEV;
+		smbios->address = phys_to_user ( smbios_entry->smbios_address );
+		smbios->len = smbios_entry->smbios_len;
+		smbios->count = smbios_entry->smbios_count;
+		smbios->version =
+			SMBIOS_VERSION ( smbios_entry->major, smbios_entry->minor );
+		DBG ( "Found 32-bit SMBIOS v%d.%d entry point at %p (%lx+%zx)\n",
+		      smbios_entry->major, smbios_entry->minor, smbios_entry,
+		      user_to_phys ( smbios->address, 0 ), smbios->len );
+		return 0;
 	}
 
-	smbios->address = phys_to_user ( smbios_entry->smbios_address );
+	DBG ( "No SMBIOS table provided\n" );
-	smbios->len = smbios_entry->smbios_len;
+	return -ENODEV;
-	smbios->count = smbios_entry->smbios_count;
-	smbios->version =
-		SMBIOS_VERSION ( smbios_entry->major, smbios_entry->minor );
-	DBG ( "Found SMBIOS v%d.%d entry point at %p (%x+%zx)\n",
-	      smbios_entry->major, smbios_entry->minor, smbios_entry,
-	      smbios_entry->smbios_address, smbios->len );
-
-	return 0;
 }
 
 PROVIDE_SMBIOS ( efi, find_smbios, efi_find_smbios );

src/interface/smbios/smbios.c

@@ -130,8 +130,8 @@ int find_smbios_structure ( unsigned int type, unsigned int instance,
 	assert ( smbios.address != UNULL );
 
 	/* Scan through list of structures */
-	while ( ( ( offset + sizeof ( structure->header ) ) < smbios.len )
+	while ( ( ( offset + sizeof ( structure->header ) ) < smbios.len ) &&
-		&& ( count < smbios.count ) ) {
+		( ( smbios.count == 0 ) || ( count < smbios.count ) ) ) {
 
 		/* Read next SMBIOS structure header */
 		copy_from_user ( &structure->header, smbios.address, offset,
@@ -157,6 +157,11 @@ int find_smbios_structure ( unsigned int type, unsigned int instance,
 		      "strings length %zx\n", offset, structure->header.type,
 		      structure->header.len, structure->strings_len );
 
+		/* Stop if we have reached an end-of-table marker */
+		if ( ( smbios.count == 0 ) &&
+		     ( structure->header.type == SMBIOS_TYPE_END ) )
+			break;
+
 		/* If this is the structure we want, return */
 		if ( ( structure->header.type == type ) &&
 		     ( instance-- == 0 ) ) {