[smbios] Support scanning for the 64-bit SMBIOS3 entry point

Support scanning for the 64-bit SMBIOS3 entry point in addition to the
32-bit SMBIOS2 entry point.

Prefer use of the 32-bit entry point if present, since this is
guaranteed to be within accessible memory.

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

diff --git a/src/arch/x86/interface/pcbios/bios_smbios.c b/src/arch/x86/interface/pcbios/bios_smbios.c
index a8c0fc325283334075381b05553fa80c02b83949..366679d3674a1986635045a92ff0d033ceaf668c 100644 (file)
--- a/src/arch/x86/interface/pcbios/bios_smbios.c
+++ b/src/arch/x86/interface/pcbios/bios_smbios.c
@@ -44,11 +44,11 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  * @v smbios           SMBIOS entry point descriptor structure to fill in
  * @ret rc             Return status code
  */
-static int bios_find_smbios ( struct smbios *smbios ) {
+static int bios_find_smbios2 ( struct smbios *smbios ) {
        struct smbios_entry entry;
        int rc;
 
-       /* Scan through BIOS segment to find SMBIOS entry point */
+       /* Scan through BIOS segment to find SMBIOS 32-bit entry point */
        if ( ( rc = find_smbios_entry ( real_to_user ( BIOS_SEG, 0 ), 0x10000,
                                        &entry ) ) != 0 )
                return rc;
@@ -62,4 +62,55 @@ static int bios_find_smbios ( struct smbios *smbios ) {
        return 0;
 }
 
+/**
+ * Find SMBIOS
+ *
+ * @v smbios           SMBIOS entry point descriptor structure to fill in
+ * @ret rc             Return status code
+ */
+static int bios_find_smbios3 ( struct smbios *smbios ) {
+       struct smbios3_entry entry;
+       int rc;
+
+       /* Scan through BIOS segment to find SMBIOS 64-bit entry point */
+       if ( ( rc = find_smbios3_entry ( real_to_user ( BIOS_SEG, 0 ), 0x10000,
+                                        &entry ) ) != 0 )
+               return rc;
+
+       /* Check that address is accessible */
+       if ( entry.smbios_address > ~( ( physaddr_t ) 0 ) ) {
+               DBG ( "SMBIOS3 at %08llx is inaccessible\n",
+                     ( ( unsigned long long ) entry.smbios_address ) );
+               return -ENOTSUP;
+       }
+
+       /* Fill in entry point descriptor structure */
+       smbios->address = phys_to_user ( entry.smbios_address );
+       smbios->len = entry.smbios_len;
+       smbios->count = 0;
+       smbios->version = SMBIOS_VERSION ( entry.major, entry.minor );
+
+       return 0;
+}
+
+/**
+ * Find SMBIOS
+ *
+ * @v smbios           SMBIOS entry point descriptor structure to fill in
+ * @ret rc             Return status code
+ */
+static int bios_find_smbios ( struct smbios *smbios ) {
+       int rc;
+
+       /* Use 32-bit table if present */
+       if ( ( rc = bios_find_smbios2 ( smbios ) ) == 0 )
+               return 0;
+
+       /* Otherwise, use 64-bit table if present and accessible */
+       if ( ( rc = bios_find_smbios3 ( smbios ) ) == 0 )
+               return 0;
+
+       return rc;
+}
+
 PROVIDE_SMBIOS ( pcbios, find_smbios, bios_find_smbios );

diff --git a/src/include/ipxe/smbios.h b/src/include/ipxe/smbios.h
index 42278fb245c54df4e07a4c492336c3d5280a3639..077a67a8502ad1da8a3d58599770036326b5033f 100644 (file)
--- a/src/include/ipxe/smbios.h
+++ b/src/include/ipxe/smbios.h
@@ -227,6 +227,8 @@ struct smbios {
 extern int find_smbios ( struct smbios *smbios );
 extern int find_smbios_entry ( userptr_t start, size_t len,
                               struct smbios_entry *entry );
+extern int find_smbios3_entry ( userptr_t start, size_t len,
+                               struct smbios3_entry *entry );
 extern int find_smbios_structure ( unsigned int type, unsigned int instance,
                                   struct smbios_structure *structure );
 extern int read_smbios_structure ( struct smbios_structure *structure,

diff --git a/src/interface/smbios/smbios.c b/src/interface/smbios/smbios.c
index 12a080da22ae427e2ede259f5d98d124d8597e6a..fdd14499f4f8bd79b8257e112362157453df6bc9 100644 (file)
--- a/src/interface/smbios/smbios.c
+++ b/src/interface/smbios/smbios.c
@@ -42,7 +42,27 @@ static struct smbios smbios = {
 };
 
 /**
- * Scan for SMBIOS entry point structure
+ * Calculate SMBIOS entry point structure checksum
+ *
+ * @v start            Start address of region
+ * @v offset           Offset of SMBIOS entry point structure
+ * @v len              Length of entry point structure
+ * @ret sum            Byte checksum
+ */
+static uint8_t smbios_checksum ( userptr_t start, size_t offset, size_t len ) {
+       size_t end = ( offset + len );
+       uint8_t sum;
+       uint8_t byte;
+
+       for ( sum = 0 ; offset < end ; offset++ ) {
+               copy_from_user ( &byte, start, offset, sizeof ( byte ) );
+               sum += byte;
+       }
+       return sum;
+}
+
+/**
+ * Scan for SMBIOS 32-bit entry point structure
  *
  * @v start            Start address of region to scan
  * @v len              Length of region to scan
@@ -51,28 +71,20 @@ static struct smbios smbios = {
  */
 int find_smbios_entry ( userptr_t start, size_t len,
                        struct smbios_entry *entry ) {
-       uint8_t buf[256]; /* 256 is maximum length possible */
        static size_t offset = 0; /* Avoid repeated attempts to locate SMBIOS */
-       size_t entry_len;
-       unsigned int i;
        uint8_t sum;
 
        /* Try to find SMBIOS */
-       for ( ; offset < len ; offset += 0x10 ) {
+       for ( ; ( offset + sizeof ( *entry ) ) <= len ; offset += 0x10 ) {
 
                /* Read start of header and verify signature */
                copy_from_user ( entry, start, offset, sizeof ( *entry ) );
                if ( entry->signature != SMBIOS_SIGNATURE )
                        continue;
 
-               /* Read whole header and verify checksum */
-               entry_len = entry->len;
-               assert ( entry_len <= sizeof ( buf ) );
-               copy_from_user ( buf, start, offset, entry_len );
-               for ( i = 0, sum = 0 ; i < entry_len ; i++ ) {
-                       sum += buf[i];
-               }
-               if ( sum != 0 ) {
+               /* Verify checksum */
+               if ( ( sum = smbios_checksum ( start, offset,
+                                              entry->len ) ) != 0 ) {
                        DBG ( "SMBIOS at %08lx has bad checksum %02x\n",
                              user_to_phys ( start, offset ), sum );
                        continue;
@@ -89,6 +101,46 @@ int find_smbios_entry ( userptr_t start, size_t len,
        return -ENODEV;
 }
 
+/**
+ * Scan for SMBIOS 64-bit entry point structure
+ *
+ * @v start            Start address of region to scan
+ * @v len              Length of region to scan
+ * @v entry            SMBIOS entry point structure to fill in
+ * @ret rc             Return status code
+ */
+int find_smbios3_entry ( userptr_t start, size_t len,
+                        struct smbios3_entry *entry ) {
+       static size_t offset = 0; /* Avoid repeated attempts to locate SMBIOS */
+       uint8_t sum;
+
+       /* Try to find SMBIOS */
+       for ( ; ( offset + sizeof ( *entry ) ) <= len ; offset += 0x10 ) {
+
+               /* Read start of header and verify signature */
+               copy_from_user ( entry, start, offset, sizeof ( *entry ) );
+               if ( entry->signature != SMBIOS3_SIGNATURE )
+                       continue;
+
+               /* Verify checksum */
+               if ( ( sum = smbios_checksum ( start, offset,
+                                              entry->len ) ) != 0 ) {
+                       DBG ( "SMBIOS3 at %08lx has bad checksum %02x\n",
+                             user_to_phys ( start, offset ), sum );
+                       continue;
+               }
+
+               /* Fill result structure */
+               DBG ( "Found SMBIOS3 v%d.%d entry point at %08lx\n",
+                     entry->major, entry->minor,
+                     user_to_phys ( start, offset ) );
+               return 0;
+       }
+
+       DBG ( "No SMBIOS3 found\n" );
+       return -ENODEV;
+}
+
 /**
  * Find SMBIOS strings terminator
  *