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[linux] Provide access to SMBIOS via /dev/mem 

Signed-off-by: Michael Brown <mcb30@ipxe.org>
pull/17/head
Michael Brown 2013-12-05 03:15:53 +00:00
parent 2f1c7e386b
commit 03957bcb47
4 changed files with 149 additions and 49 deletions
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48
src/arch/i386/interface/pcbios/bios_smbios.c
View File

@ -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;
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;
}
PROVIDE_SMBIOS ( pcbios, find_smbios, bios_find_smbios );

2
src/include/ipxe/smbios.h
View File

@ -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,

92
src/interface/linux/linux_smbios.c
View File

@ -1,5 +1,5 @@
/*
* Copyright (C) 2010 Piotr Jaroszyński <p.jaroszynski@gmail.com>
* Copyright (C) 2013 Michael Brown <mbrown@fensystems.co.uk>.
*
* 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 );
#include <errno.h>
#include <linux_api.h>
#include <ipxe/linux.h>
#include <ipxe/smbios.h>
/** 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 );

48
src/interface/smbios/smbios.c
View File

@ -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
*