- 根目录:
- arch
- x86
- platform
- efi
- efi.c
/*
* Common EFI (Extensible Firmware Interface) support functions
* Based on Extensible Firmware Interface Specification version 1.0
*
* Copyright (C) 1999 VA Linux Systems
* Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
* Copyright (C) 1999-2002 Hewlett-Packard Co.
* David Mosberger-Tang <davidm@hpl.hp.com>
* Stephane Eranian <eranian@hpl.hp.com>
* Copyright (C) 2005-2008 Intel Co.
* Fenghua Yu <fenghua.yu@intel.com>
* Bibo Mao <bibo.mao@intel.com>
* Chandramouli Narayanan <mouli@linux.intel.com>
* Huang Ying <ying.huang@intel.com>
*
* Copied from efi_32.c to eliminate the duplicated code between EFI
* 32/64 support code. --ying 2007-10-26
*
* All EFI Runtime Services are not implemented yet as EFI only
* supports physical mode addressing on SoftSDV. This is to be fixed
* in a future version. --drummond 1999-07-20
*
* Implemented EFI runtime services and virtual mode calls. --davidm
*
* Goutham Rao: <goutham.rao@intel.com>
* Skip non-WB memory and ignore empty memory ranges.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/efi.h>
#include <linux/export.h>
#include <linux/bootmem.h>
#include <linux/memblock.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/time.h>
#include <linux/io.h>
#include <linux/reboot.h>
#include <linux/bcd.h>
#include <asm/setup.h>
#include <asm/efi.h>
#include <asm/time.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/x86_init.h>
#define EFI_DEBUG 1
#define PFX "EFI: "
int efi_enabled;
EXPORT_SYMBOL(efi_enabled);
struct efi __read_mostly efi = {
.mps = EFI_INVALID_TABLE_ADDR,
.acpi = EFI_INVALID_TABLE_ADDR,
.acpi20 = EFI_INVALID_TABLE_ADDR,
.smbios = EFI_INVALID_TABLE_ADDR,
.sal_systab = EFI_INVALID_TABLE_ADDR,
.boot_info = EFI_INVALID_TABLE_ADDR,
.hcdp = EFI_INVALID_TABLE_ADDR,
.uga = EFI_INVALID_TABLE_ADDR,
.uv_systab = EFI_INVALID_TABLE_ADDR,
};
EXPORT_SYMBOL(efi);
struct efi_memory_map memmap;
static struct efi efi_phys __initdata;
static efi_system_table_t efi_systab __initdata;
static int __init setup_noefi(char *arg)
{
efi_enabled = 0;
return 0;
}
early_param("noefi", setup_noefi);
int add_efi_memmap;
EXPORT_SYMBOL(add_efi_memmap);
static int __init setup_add_efi_memmap(char *arg)
{
add_efi_memmap = 1;
return 0;
}
early_param("add_efi_memmap", setup_add_efi_memmap);
static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)
{
unsigned long flags;
efi_status_t status;
spin_lock_irqsave(&rtc_lock, flags);
status = efi_call_virt2(get_time, tm, tc);
spin_unlock_irqrestore(&rtc_lock, flags);
return status;
}
static efi_status_t virt_efi_set_time(efi_time_t *tm)
{
unsigned long flags;
efi_status_t status;
spin_lock_irqsave(&rtc_lock, flags);
status = efi_call_virt1(set_time, tm);
spin_unlock_irqrestore(&rtc_lock, flags);
return status;
}
static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled,
efi_bool_t *pending,
efi_time_t *tm)
{
unsigned long flags;
efi_status_t status;
spin_lock_irqsave(&rtc_lock, flags);
status = efi_call_virt3(get_wakeup_time,
enabled, pending, tm);
spin_unlock_irqrestore(&rtc_lock, flags);
return status;
}
static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
{
unsigned long flags;
efi_status_t status;
spin_lock_irqsave(&rtc_lock, flags);
status = efi_call_virt2(set_wakeup_time,
enabled, tm);
spin_unlock_irqrestore(&rtc_lock, flags);
return status;
}
static efi_status_t virt_efi_get_variable(efi_char16_t *name,
efi_guid_t *vendor,
u32 *attr,
unsigned long *data_size,
void *data)
{
return efi_call_virt5(get_variable,
name, vendor, attr,
data_size, data);
}
static efi_status_t virt_efi_get_next_variable(unsigned long *name_size,
efi_char16_t *name,
efi_guid_t *vendor)
{
return efi_call_virt3(get_next_variable,
name_size, name, vendor);
}
static efi_status_t virt_efi_set_variable(efi_char16_t *name,
efi_guid_t *vendor,
u32 attr,
unsigned long data_size,
void *data)
{
return efi_call_virt5(set_variable,
name, vendor, attr,
data_size, data);
}
static efi_status_t virt_efi_query_variable_info(u32 attr,
u64 *storage_space,
u64 *remaining_space,
u64 *max_variable_size)
{
if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
return EFI_UNSUPPORTED;
return efi_call_virt4(query_variable_info, attr, storage_space,
remaining_space, max_variable_size);
}
static efi_status_t virt_efi_get_next_high_mono_count(u32 *count)
{
return efi_call_virt1(get_next_high_mono_count, count);
}
static void virt_efi_reset_system(int reset_type,
efi_status_t status,
unsigned long data_size,
efi_char16_t *data)
{
efi_call_virt4(reset_system, reset_type, status,
data_size, data);
}
static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules,
unsigned long count,
unsigned long sg_list)
{
if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
return EFI_UNSUPPORTED;
return efi_call_virt3(update_capsule, capsules, count, sg_list);
}
static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules,
unsigned long count,
u64 *max_size,
int *reset_type)
{
if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
return EFI_UNSUPPORTED;
return efi_call_virt4(query_capsule_caps, capsules, count, max_size,
reset_type);
}
static efi_status_t __init phys_efi_set_virtual_address_map(
unsigned long memory_map_size,
unsigned long descriptor_size,
u32 descriptor_version,
efi_memory_desc_t *virtual_map)
{
efi_status_t status;
efi_call_phys_prelog();
status = efi_call_phys4(efi_phys.set_virtual_address_map,
memory_map_size, descriptor_size,
descriptor_version, virtual_map);
efi_call_phys_epilog();
return status;
}
static efi_status_t __init phys_efi_get_time(efi_time_t *tm,
efi_time_cap_t *tc)
{
unsigned long flags;
efi_status_t status;
spin_lock_irqsave(&rtc_lock, flags);
efi_call_phys_prelog();
status = efi_call_phys2(efi_phys.get_time, virt_to_phys(tm),
virt_to_phys(tc));
efi_call_phys_epilog();
spin_unlock_irqrestore(&rtc_lock, flags);
return status;
}
int efi_set_rtc_mmss(unsigned long nowtime)
{
int real_seconds, real_minutes;
efi_status_t status;
efi_time_t eft;
efi_time_cap_t cap;
status = efi.get_time(&eft, &cap);
if (status != EFI_SUCCESS) {
printk(KERN_ERR "Oops: efitime: can't read time!\n");
return -1;
}
real_seconds = nowtime % 60;
real_minutes = nowtime / 60;
if (((abs(real_minutes - eft.minute) + 15)/30) & 1)
real_minutes += 30;
real_minutes %= 60;
eft.minute = real_minutes;
eft.second = real_seconds;
status = efi.set_time(&eft);
if (status != EFI_SUCCESS) {
printk(KERN_ERR "Oops: efitime: can't write time!\n");
return -1;
}
return 0;
}
unsigned long efi_get_time(void)
{
efi_status_t status;
efi_time_t eft;
efi_time_cap_t cap;
status = efi.get_time(&eft, &cap);
if (status != EFI_SUCCESS)
printk(KERN_ERR "Oops: efitime: can't read time!\n");
return mktime(eft.year, eft.month, eft.day, eft.hour,
eft.minute, eft.second);
}
/*
* Tell the kernel about the EFI memory map. This might include
* more than the max 128 entries that can fit in the e820 legacy
* (zeropage) memory map.
*/
static void __init do_add_efi_memmap(void)
{
void *p;
for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
efi_memory_desc_t *md = p;
unsigned long long start = md->phys_addr;
unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
int e820_type;
switch (md->type) {
case EFI_LOADER_CODE:
case EFI_LOADER_DATA:
case EFI_BOOT_SERVICES_CODE:
case EFI_BOOT_SERVICES_DATA:
case EFI_CONVENTIONAL_MEMORY:
if (md->attribute & EFI_MEMORY_WB)
e820_type = E820_RAM;
else
e820_type = E820_RESERVED;
break;
case EFI_ACPI_RECLAIM_MEMORY:
e820_type = E820_ACPI;
break;
case EFI_ACPI_MEMORY_NVS:
e820_type = E820_NVS;
break;
case EFI_UNUSABLE_MEMORY:
e820_type = E820_UNUSABLE;
break;
default:
/*
* EFI_RESERVED_TYPE EFI_RUNTIME_SERVICES_CODE
* EFI_RUNTIME_SERVICES_DATA EFI_MEMORY_MAPPED_IO
* EFI_MEMORY_MAPPED_IO_PORT_SPACE EFI_PAL_CODE
*/
e820_type = E820_RESERVED;
break;
}
e820_add_region(start, size, e820_type);
}
sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
}
void __init efi_memblock_x86_reserve_range(void)
{
unsigned long pmap;
#ifdef CONFIG_X86_32
pmap = boot_params.efi_info.efi_memmap;
#else
pmap = (boot_params.efi_info.efi_memmap |
((__u64)boot_params.efi_info.efi_memmap_hi<<32));
#endif
memmap.phys_map = (void *)pmap;
memmap.nr_map = boot_params.efi_info.efi_memmap_size /
boot_params.efi_info.efi_memdesc_size;
memmap.desc_version = boot_params.efi_info.efi_memdesc_version;
memmap.desc_size = boot_params.efi_info.efi_memdesc_size;
memblock_reserve(pmap, memmap.nr_map * memmap.desc_size);
}
#if EFI_DEBUG
static void __init print_efi_memmap(void)
{
efi_memory_desc_t *md;
void *p;
int i;
for (p = memmap.map, i = 0;
p < memmap.map_end;
p += memmap.desc_size, i++) {
md = p;
printk(KERN_INFO PFX "mem%02u: type=%u, attr=0x%llx, "
"range=[0x%016llx-0x%016llx) (%lluMB)\n",
i, md->type, md->attribute, md->phys_addr,
md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT),
(md->num_pages >> (20 - EFI_PAGE_SHIFT)));
}
}
#endif /* EFI_DEBUG */
void __init efi_reserve_boot_services(void)
{
void *p;
for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
efi_memory_desc_t *md = p;
u64 start = md->phys_addr;
u64 size = md->num_pages << EFI_PAGE_SHIFT;
if (md->type != EFI_BOOT_SERVICES_CODE &&
md->type != EFI_BOOT_SERVICES_DATA)
continue;
/* Only reserve where possible:
* - Not within any already allocated areas
* - Not over any memory area (really needed, if above?)
* - Not within any part of the kernel
* - Not the bios reserved area
*/
if ((start+size >= virt_to_phys(_text)
&& start <= virt_to_phys(_end)) ||
!e820_all_mapped(start, start+size, E820_RAM) ||
memblock_is_region_reserved(start, size)) {
/* Could not reserve, skip it */
md->num_pages = 0;
memblock_dbg(PFX "Could not reserve boot range "
"[0x%010llx-0x%010llx]\n",
start, start+size-1);
} else
memblock_reserve(start, size);
}
}
static void __init efi_free_boot_services(void)
{
void *p;
for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
efi_memory_desc_t *md = p;
unsigned long long start = md->phys_addr;
unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
if (md->type != EFI_BOOT_SERVICES_CODE &&
md->type != EFI_BOOT_SERVICES_DATA)
continue;
/* Could not reserve boot area */
if (!size)
continue;
free_bootmem_late(start, size);
}
}
void __init efi_init(void)
{
efi_config_table_t *config_tables;
efi_runtime_services_t *runtime;
efi_char16_t *c16;
char vendor[100] = "unknown";
int i = 0;
void *tmp;
#ifdef CONFIG_X86_32
efi_phys.systab = (efi_system_table_t *)boot_params.efi_info.efi_systab;
#else
efi_phys.systab = (efi_system_table_t *)
(boot_params.efi_info.efi_systab |
((__u64)boot_params.efi_info.efi_systab_hi<<32));
#endif
efi.systab = early_ioremap((unsigned long)efi_phys.systab,
sizeof(efi_system_table_t));
if (efi.systab == NULL)
printk(KERN_ERR "Couldn't map the EFI system table!\n");
memcpy(&efi_systab, efi.systab, sizeof(efi_system_table_t));
early_iounmap(efi.systab, sizeof(efi_system_table_t));
efi.systab = &efi_systab;
/*
* Verify the EFI Table
*/
if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
printk(KERN_ERR "EFI system table signature incorrect!\n");
if ((efi.systab->hdr.revision >> 16) == 0)
printk(KERN_ERR "Warning: EFI system table version "
"%d.%02d, expected 1.00 or greater!\n",
efi.systab->hdr.revision >> 16,
efi.systab->hdr.revision & 0xffff);
/*
* Show what we know for posterity
*/
c16 = tmp = early_ioremap(efi.systab->fw_vendor, 2);
if (c16) {
for (i = 0; i < sizeof(vendor) - 1 && *c16; ++i)
vendor[i] = *c16++;
vendor[i] = '\0';
} else
printk(KERN_ERR PFX "Could not map the firmware vendor!\n");
early_iounmap(tmp, 2);
printk(KERN_INFO "EFI v%u.%.02u by %s\n",
efi.systab->hdr.revision >> 16,
efi.systab->hdr.revision & 0xffff, vendor);
/*
* Let's see what config tables the firmware passed to us.
*/
config_tables = early_ioremap(
efi.systab->tables,
efi.systab->nr_tables * sizeof(efi_config_table_t));
if (config_tables == NULL)
printk(KERN_ERR "Could not map EFI Configuration Table!\n");
printk(KERN_INFO);
for (i = 0; i < efi.systab->nr_tables; i++) {
if (!efi_guidcmp(config_tables[i].guid, MPS_TABLE_GUID)) {
efi.mps = config_tables[i].table;
printk(" MPS=0x%lx ", config_tables[i].table);
} else if (!efi_guidcmp(config_tables[i].guid,
ACPI_20_TABLE_GUID)) {
efi.acpi20 = config_tables[i].table;
printk(" ACPI 2.0=0x%lx ", config_tables[i].table);
} else if (!efi_guidcmp(config_tables[i].guid,
ACPI_TABLE_GUID)) {
efi.acpi = config_tables[i].table;
printk(" ACPI=0x%lx ", config_tables[i].table);
} else if (!efi_guidcmp(config_tables[i].guid,
SMBIOS_TABLE_GUID)) {
efi.smbios = config_tables[i].table;
printk(" SMBIOS=0x%lx ", config_tables[i].table);
#ifdef CONFIG_X86_UV
} else if (!efi_guidcmp(config_tables[i].guid,
UV_SYSTEM_TABLE_GUID)) {
efi.uv_systab = config_tables[i].table;
printk(" UVsystab=0x%lx ", config_tables[i].table);
#endif
} else if (!efi_guidcmp(config_tables[i].guid,
HCDP_TABLE_GUID)) {
efi.hcdp = config_tables[i].table;
printk(" HCDP=0x%lx ", config_tables[i].table);
} else if (!efi_guidcmp(config_tables[i].guid,
UGA_IO_PROTOCOL_GUID)) {
efi.uga = config_tables[i].table;
printk(" UGA=0x%lx ", config_tables[i].table);
}
}
printk("\n");
early_iounmap(config_tables,
efi.systab->nr_tables * sizeof(efi_config_table_t));
/*
* Check out the runtime services table. We need to map
* the runtime services table so that we can grab the physical
* address of several of the EFI runtime functions, needed to
* set the firmware into virtual mode.
*/
runtime = early_ioremap((unsigned long)efi.systab->runtime,
sizeof(efi_runtime_services_t));
if (runtime != NULL) {
/*
* We will only need *early* access to the following
* two EFI runtime services before set_virtual_address_map
* is invoked.
*/
efi_phys.get_time = (efi_get_time_t *)runtime->get_time;
efi_phys.set_virtual_address_map =
(efi_set_virtual_address_map_t *)
runtime->set_virtual_address_map;
/*
* Make efi_get_time can be called before entering
* virtual mode.
*/
efi.get_time = phys_efi_get_time;
} else
printk(KERN_ERR "Could not map the EFI runtime service "
"table!\n");
early_iounmap(runtime, sizeof(efi_runtime_services_t));
/* Map the EFI memory map */
memmap.map = early_ioremap((unsigned long)memmap.phys_map,
memmap.nr_map * memmap.desc_size);
if (memmap.map == NULL)
printk(KERN_ERR "Could not map the EFI memory map!\n");
memmap.map_end = memmap.map + (memmap.nr_map * memmap.desc_size);
if (memmap.desc_size != sizeof(efi_memory_desc_t))
printk(KERN_WARNING
"Kernel-defined memdesc doesn't match the one from EFI!\n");
if (add_efi_memmap)
do_add_efi_memmap();
#ifdef CONFIG_X86_32
x86_platform.get_wallclock = efi_get_time;
x86_platform.set_wallclock = efi_set_rtc_mmss;
#endif
#if EFI_DEBUG
print_efi_memmap();
#endif
}
void __init efi_set_executable(efi_memory_desc_t *md, bool executable)
{
u64 addr, npages;
addr = md->virt_addr;
npages = md->num_pages;
memrange_efi_to_native(&addr, &npages);
if (executable)
set_memory_x(addr, npages);
else
set_memory_nx(addr, npages);
}
static void __init runtime_code_page_mkexec(void)
{
efi_memory_desc_t *md;
void *p;
/* Make EFI runtime service code area executable */
for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
md = p;
if (md->type != EFI_RUNTIME_SERVICES_CODE)
continue;
efi_set_executable(md, true);
}
}
/*
* This function will switch the EFI runtime services to virtual mode.
* Essentially, look through the EFI memmap and map every region that
* has the runtime attribute bit set in its memory descriptor and update
* that memory descriptor with the virtual address obtained from ioremap().
* This enables the runtime services to be called without having to
* thunk back into physical mode for every invocation.
*/
void __init efi_enter_virtual_mode(void)
{
efi_memory_desc_t *md, *prev_md = NULL;
efi_status_t status;
unsigned long size;
u64 end, systab, addr, npages, end_pfn;
void *p, *va, *new_memmap = NULL;
int count = 0;
efi.systab = NULL;
/* Merge contiguous regions of the same type and attribute */
for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
u64 prev_size;
md = p;
if (!prev_md) {
prev_md = md;
continue;
}
if (prev_md->type != md->type ||
prev_md->attribute != md->attribute) {
prev_md = md;
continue;
}
prev_size = prev_md->num_pages << EFI_PAGE_SHIFT;
if (md->phys_addr == (prev_md->phys_addr + prev_size)) {
prev_md->num_pages += md->num_pages;
md->type = EFI_RESERVED_TYPE;
md->attribute = 0;
continue;
}
prev_md = md;
}
for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
md = p;
if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
md->type != EFI_BOOT_SERVICES_CODE &&
md->type != EFI_BOOT_SERVICES_DATA)
continue;
size = md->num_pages << EFI_PAGE_SHIFT;
end = md->phys_addr + size;
end_pfn = PFN_UP(end);
if (end_pfn <= max_low_pfn_mapped
|| (end_pfn > (1UL << (32 - PAGE_SHIFT))
&& end_pfn <= max_pfn_mapped))
va = __va(md->phys_addr);
else
va = efi_ioremap(md->phys_addr, size, md->type);
md->virt_addr = (u64) (unsigned long) va;
if (!va) {
printk(KERN_ERR PFX "ioremap of 0x%llX failed!\n",
(unsigned long long)md->phys_addr);
continue;
}
if (!(md->attribute & EFI_MEMORY_WB)) {
addr = md->virt_addr;
npages = md->num_pages;
memrange_efi_to_native(&addr, &npages);
set_memory_uc(addr, npages);
}
systab = (u64) (unsigned long) efi_phys.systab;
if (md->phys_addr <= systab && systab < end) {
systab += md->virt_addr - md->phys_addr;
efi.systab = (efi_system_table_t *) (unsigned long) systab;
}
new_memmap = krealloc(new_memmap,
(count + 1) * memmap.desc_size,
GFP_KERNEL);
memcpy(new_memmap + (count * memmap.desc_size), md,
memmap.desc_size);
count++;
}
BUG_ON(!efi.systab);
status = phys_efi_set_virtual_address_map(
memmap.desc_size * count,
memmap.desc_size,
memmap.desc_version,
(efi_memory_desc_t *)__pa(new_memmap));
if (status != EFI_SUCCESS) {
printk(KERN_ALERT "Unable to switch EFI into virtual mode "
"(status=%lx)!\n", status);
panic("EFI call to SetVirtualAddressMap() failed!");
}
/*
* Thankfully, it does seem that no runtime services other than
* SetVirtualAddressMap() will touch boot services code, so we can
* get rid of it all at this point
*/
efi_free_boot_services();
/*
* Now that EFI is in virtual mode, update the function
* pointers in the runtime service table to the new virtual addresses.
*
* Call EFI services through wrapper functions.
*/
efi.get_time = virt_efi_get_time;
efi.set_time = virt_efi_set_time;
efi.get_wakeup_time = virt_efi_get_wakeup_time;
efi.set_wakeup_time = virt_efi_set_wakeup_time;
efi.get_variable = virt_efi_get_variable;
efi.get_next_variable = virt_efi_get_next_variable;
efi.set_variable = virt_efi_set_variable;
efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count;
efi.reset_system = virt_efi_reset_system;
efi.set_virtual_address_map = NULL;
efi.query_variable_info = virt_efi_query_variable_info;
efi.update_capsule = virt_efi_update_capsule;
efi.query_capsule_caps = virt_efi_query_capsule_caps;
if (__supported_pte_mask & _PAGE_NX)
runtime_code_page_mkexec();
early_iounmap(memmap.map, memmap.nr_map * memmap.desc_size);
memmap.map = NULL;
kfree(new_memmap);
}
/*
* Convenience functions to obtain memory types and attributes
*/
u32 efi_mem_type(unsigned long phys_addr)
{
efi_memory_desc_t *md;
void *p;
for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
md = p;
if ((md->phys_addr <= phys_addr) &&
(phys_addr < (md->phys_addr +
(md->num_pages << EFI_PAGE_SHIFT))))
return md->type;
}
return 0;
}
u64 efi_mem_attributes(unsigned long phys_addr)
{
efi_memory_desc_t *md;
void *p;
for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
md = p;
if ((md->phys_addr <= phys_addr) &&
(phys_addr < (md->phys_addr +
(md->num_pages << EFI_PAGE_SHIFT))))
return md->attribute;
}
return 0;
}