From 03957bcb472e5065a46bd56e9b8b1f902fac4b3b Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Thu, 5 Dec 2013 03:15:53 +0000 Subject: [PATCH] [linux] Provide access to SMBIOS via /dev/mem Signed-off-by: Michael Brown --- src/arch/i386/interface/pcbios/bios_smbios.c | 52 +++-------- src/include/ipxe/smbios.h | 2 + src/interface/linux/linux_smbios.c | 96 ++++++++++++++++++-- src/interface/smbios/smbios.c | 48 ++++++++++ 4 files changed, 149 insertions(+), 49 deletions(-) diff --git a/src/arch/i386/interface/pcbios/bios_smbios.c b/src/arch/i386/interface/pcbios/bios_smbios.c index 76a32e93..dd7897e2 100644 --- a/src/arch/i386/interface/pcbios/bios_smbios.c +++ b/src/arch/i386/interface/pcbios/bios_smbios.c @@ -41,49 +41,21 @@ FILE_LICENCE ( GPL2_OR_LATER ); * @ret rc Return status code */ static int bios_find_smbios ( struct smbios *smbios ) { - union { - struct smbios_entry entry; - uint8_t bytes[256]; /* 256 is maximum length possible */ - } u; - static unsigned int offset = 0; - size_t len; - unsigned int i; - uint8_t sum; + struct smbios_entry entry; + int rc; - /* Try to find SMBIOS */ - for ( ; offset < 0x10000 ; offset += 0x10 ) { + /* Scan through BIOS segment to find SMBIOS entry point */ + if ( ( rc = find_smbios_entry ( real_to_user ( BIOS_SEG, 0 ), 0x10000, + &entry ) ) != 0 ) + return rc; - /* Read start of header and verify signature */ - copy_from_real ( &u.entry, BIOS_SEG, offset, - sizeof ( u.entry )); - if ( u.entry.signature != SMBIOS_SIGNATURE ) - continue; + /* Fill in entry point descriptor structure */ + smbios->address = phys_to_user ( entry.smbios_address ); + smbios->len = entry.smbios_len; + smbios->count = entry.smbios_count; + smbios->version = SMBIOS_VERSION ( entry.major, entry.minor ); - /* Read whole header and verify checksum */ - len = u.entry.len; - copy_from_real ( &u.bytes, BIOS_SEG, offset, len ); - for ( i = 0 , sum = 0 ; i < len ; i++ ) { - sum += u.bytes[i]; - } - if ( sum != 0 ) { - DBG ( "SMBIOS at %04x:%04x has bad checksum %02x\n", - BIOS_SEG, offset, sum ); - continue; - } - - /* Fill result structure */ - DBG ( "Found SMBIOS v%d.%d entry point at %04x:%04x\n", - u.entry.major, u.entry.minor, BIOS_SEG, offset ); - smbios->address = phys_to_user ( u.entry.smbios_address ); - smbios->len = u.entry.smbios_len; - smbios->count = u.entry.smbios_count; - smbios->version = - SMBIOS_VERSION ( u.entry.major, u.entry.minor ); - return 0; - } - - DBG ( "No SMBIOS found\n" ); - return -ENODEV; + return 0; } PROVIDE_SMBIOS ( pcbios, find_smbios, bios_find_smbios ); diff --git a/src/include/ipxe/smbios.h b/src/include/ipxe/smbios.h index aaba6cb1..1a34ac04 100644 --- a/src/include/ipxe/smbios.h +++ b/src/include/ipxe/smbios.h @@ -162,6 +162,8 @@ struct smbios { #define SMBIOS_VERSION( major, minor ) ( ( (major) << 8 ) | (minor) ) 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_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/linux/linux_smbios.c b/src/interface/linux/linux_smbios.c index f99120bf..6e5174d2 100644 --- a/src/interface/linux/linux_smbios.c +++ b/src/interface/linux/linux_smbios.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2010 Piotr Jaroszyński + * Copyright (C) 2013 Michael Brown . * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as @@ -13,25 +13,103 @@ * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software - * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. */ -FILE_LICENCE(GPL2_OR_LATER); +FILE_LICENCE ( GPL2_OR_LATER ); #include +#include +#include #include +/** SMBIOS filename */ +static const char smbios_filename[] = "/dev/mem"; + +/** SMBIOS entry point scan region start address */ +#define SMBIOS_ENTRY_START 0xf0000 + +/** SMBIOS entry point scan region length */ +#define SMBIOS_ENTRY_LEN 0x10000 + +/** SMBIOS mapping alignment */ +#define SMBIOS_ALIGN 0x1000 + /** * Find SMBIOS * - * Not implemented currently. - * * @v smbios SMBIOS entry point descriptor structure to fill in * @ret rc Return status code */ -static int linux_find_smbios(struct smbios *smbios __unused) -{ - return -ENODEV; +static int linux_find_smbios ( struct smbios *smbios ) { + struct smbios_entry entry; + void *entry_mem; + void *smbios_mem; + size_t smbios_offset; + size_t smbios_indent; + size_t smbios_len; + int fd; + int rc; + + /* Open SMBIOS file */ + fd = linux_open ( smbios_filename, O_RDONLY ); + if ( fd < 0 ) { + rc = -ELINUX ( linux_errno ); + DBGC ( smbios, "SMBIOS could not open %s: %s\n", + smbios_filename, linux_strerror ( linux_errno ) ); + goto err_open; + } + + /* Map the region potentially containing the SMBIOS entry point */ + entry_mem = linux_mmap ( NULL, SMBIOS_ENTRY_LEN, PROT_READ, MAP_SHARED, + fd, SMBIOS_ENTRY_START ); + if ( entry_mem == MAP_FAILED ) { + rc = -ELINUX ( linux_errno ); + DBGC ( smbios, "SMBIOS could not mmap %s (%#x+%#x): %s\n", + smbios_filename, SMBIOS_ENTRY_START, SMBIOS_ENTRY_LEN, + linux_strerror ( linux_errno ) ); + goto err_mmap_entry; + } + + /* Scan for the SMBIOS entry point */ + if ( ( rc = find_smbios_entry ( virt_to_user ( entry_mem ), + SMBIOS_ENTRY_LEN, &entry ) ) != 0 ) + goto err_find_entry; + + /* Map the region containing the SMBIOS structures */ + smbios_indent = ( entry.smbios_address & ( SMBIOS_ALIGN - 1 ) ); + smbios_offset = ( entry.smbios_address - smbios_indent ); + smbios_len = ( entry.smbios_len + smbios_indent ); + smbios_mem = linux_mmap ( NULL, smbios_len, PROT_READ, MAP_SHARED, + fd, smbios_offset ); + if ( smbios_mem == MAP_FAILED ) { + rc = -ELINUX ( linux_errno ); + DBGC ( smbios, "SMBIOS could not mmap %s (%#zx+%#zx): %s\n", + smbios_filename, smbios_offset, smbios_len, + linux_strerror ( linux_errno ) ); + goto err_mmap_smbios; + } + + /* Fill in entry point descriptor structure */ + smbios->address = virt_to_user ( smbios_mem + smbios_indent ); + smbios->len = entry.smbios_len; + smbios->count = entry.smbios_count; + smbios->version = SMBIOS_VERSION ( entry.major, entry.minor ); + + /* Unmap the entry point region (no longer required) */ + linux_munmap ( entry_mem, SMBIOS_ENTRY_LEN ); + + return 0; + + linux_munmap ( smbios_mem, smbios_len ); + err_mmap_smbios: + err_find_entry: + linux_munmap ( entry_mem, SMBIOS_ENTRY_LEN ); + err_mmap_entry: + linux_close ( fd ); + err_open: + return rc; } -PROVIDE_SMBIOS(linux, find_smbios, linux_find_smbios); +PROVIDE_SMBIOS ( linux, find_smbios, linux_find_smbios ); diff --git a/src/interface/smbios/smbios.c b/src/interface/smbios/smbios.c index 90907e18..85694342 100644 --- a/src/interface/smbios/smbios.c +++ b/src/interface/smbios/smbios.c @@ -37,6 +37,54 @@ static struct smbios smbios = { .address = UNULL, }; +/** + * Scan for SMBIOS 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_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 ) { + + /* 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 ) { + DBG ( "SMBIOS at %08lx has bad checksum %02x\n", + user_to_phys ( start, offset ), sum ); + continue; + } + + /* Fill result structure */ + DBG ( "Found SMBIOS v%d.%d entry point at %08lx\n", + entry->major, entry->minor, + user_to_phys ( start, offset ) ); + return 0; + } + + DBG ( "No SMBIOS found\n" ); + return -ENODEV; +} + /** * Find SMBIOS strings terminator *