From fa62213231a882eb6bbcefa7ad1106bdb9aaeae2 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Fri, 29 Dec 2023 19:38:12 +0000 Subject: [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 --- src/arch/x86/interface/pcbios/bios_smbios.c | 55 +++++++++++++++++++- src/include/ipxe/smbios.h | 2 + src/interface/smbios/smbios.c | 78 ++++++++++++++++++++++++----- 3 files changed, 120 insertions(+), 15 deletions(-) diff --git a/src/arch/x86/interface/pcbios/bios_smbios.c b/src/arch/x86/interface/pcbios/bios_smbios.c index a8c0fc32..366679d3 100644 --- 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 42278fb2..077a67a8 100644 --- 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 12a080da..fdd14499 100644 --- 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 * -- cgit v1.2.3-55-g7522