efi_table.c File Reference

EFI configuration tables. More...

#include <assert.h>
#include <errno.h>
#include <string.h>
#include <ipxe/efi/efi.h>
#include <ipxe/efi/efi_table.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
	FILE_SECBOOT (PERMITTED)
void *	efi_find_table (EFI_GUID *guid)
	Look up EFI configuration table.
int	efi_install_table (struct efi_table *table, const void *data, void **backup)
	Install EFI configuration table.
int	efi_uninstall_table (struct efi_table *table, void **backup)
	Uninstall EFI configuration table.

Detailed Description

EFI configuration tables.

Definition in file efi_table.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

FILE_SECBOOT()

FILE_SECBOOT

(

PERMITTED

)

efi_find_table()

void * efi_find_table

(

EFI_GUID *

guid

)

Look up EFI configuration table.

Parameters

guid	Configuration table GUID

Return values

table

Configuration table, or NULL

Definition at line 45 of file efi_table.c.

                                         {
        void *table;
        unsigned int i;
 
        /* Scan for installed table */
        for ( i = 0 ; i < efi_systab->NumberOfTableEntries ; i++ ) {
                if ( memcmp ( &efi_systab->ConfigurationTable[i].VendorGuid,
                              guid, sizeof ( *guid ) ) == 0 ) {
                        table = efi_systab->ConfigurationTable[i].VendorTable;
                        DBGC ( guid, "EFITAB %s is at %p\n",
                               efi_guid_ntoa ( guid ), table );
                        return table;
                }
        }
 
        return NULL;
}

References DBGC, efi_guid_ntoa(), efi_systab, guid, memcmp(), and NULL.

Referenced by efi_init(), and efi_install_table().

efi_install_table()

int efi_install_table	(	struct efi_table *	table,
		const void *	data,
		void **	backup )

Install EFI configuration table.

Parameters

table	Configuration table type
data	Configuration table data, or NULL to uninstall
backup	Table backup, or NULL to not back up old table

Return values

rc	Return status code

Definition at line 71 of file efi_table.c.

                                        {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        EFI_GUID *guid = table->guid;
        void *copy;
        void *new;
        void *old;
        size_t old_len;
        size_t new_len;
        EFI_STATUS efirc;
        int rc;
 
        /* Get currently installed table, if any */
        old = efi_find_table ( guid );
        old_len = ( old ? table->len ( old ) : 0 );
 
        /* Create backup copy, if applicable */
        if ( old_len && backup ) {
                if ( ( efirc = bs->AllocatePool ( EfiBootServicesData, old_len,
                                                  &copy ) ) != 0 ) {
                        rc = -EEFI ( efirc );
                        goto err_backup;
                }
                memcpy ( copy, old, old_len );
                DBGC ( table, "EFITAB %s %p+%#zx backed up\n",
                       efi_guid_ntoa ( guid ), old, old_len );
        } else {
                copy = NULL;
        }
 
        /* Create installable runtime services data copy, if applicable */
        new_len = ( data ? table->len ( data ) : 0 );
        if ( new_len ) {
                if ( ( efirc = bs->AllocatePool ( EfiRuntimeServicesData,
                                                  new_len, &new ) ) != 0 ) {
                        rc = -EEFI ( efirc );
                        goto err_allocate;
                }
                memcpy ( new, data, new_len );
        } else {
                new = NULL;
        }
 
        /* (Un)install configuration table, if applicable */
        if ( new || old ) {
                if ( ( efirc = bs->InstallConfigurationTable ( guid,
                                                               new ) ) != 0 ) {
                        rc = -EEFI ( efirc );
                        DBGC ( table, "EFITAB %s could not install: %s\n",
                               efi_guid_ntoa ( guid ), strerror ( rc ) );
                        goto err_install;
                }
                if ( old ) {
                        DBGC ( table, "EFITAB %s %p+%#zx uninstalled\n",
                               efi_guid_ntoa ( guid ), old, old_len );
                }
                if ( new ) {
                        DBGC ( table, "EFITAB %s %p+%#zx installed\n",
                               efi_guid_ntoa ( guid ), new, new_len );
                }
        }
 
        /* Record backup copy, if applicable */
        if ( backup ) {
                if ( *backup )
                        bs->FreePool ( *backup );
                *backup = copy;
        }
 
        /* Sanity check */
        assert ( efi_find_table ( guid ) == new );
 
        return 0;
 
 err_install:
        if ( new )
                bs->FreePool ( new );
 err_allocate:
        if ( copy )
                bs->FreePool ( copy );
 err_backup:
        return rc;
}

References EFI_BOOT_SERVICES::AllocatePool, assert, data, DBGC, EEFI, efi_find_table(), efi_guid_ntoa(), efi_systab, EfiBootServicesData, EfiRuntimeServicesData, EFI_BOOT_SERVICES::FreePool, efi_table::guid, guid, EFI_BOOT_SERVICES::InstallConfigurationTable, efi_table::len, memcpy(), NULL, old, rc, and strerror().

Referenced by efi_fdt_install(), and efi_uninstall_table().

efi_uninstall_table()

int efi_uninstall_table	(	struct efi_table *	table,
		void **	backup )

Uninstall EFI configuration table.

Parameters

table	Configuration table type
backup	Table backup (or NULL to not restore old table)

Return values

rc	Return status code

Definition at line 162 of file efi_table.c.

                                                                   {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        void *old;
        int rc;
 
        /* Uninstall or reinstall as applicable */
        old = ( backup ? *backup : NULL );
        if ( ( rc = efi_install_table ( table, old, NULL ) ) != 0 )
                return rc;
 
        /* Free backup copy, if applicable */
        if ( backup && *backup ) {
                bs->FreePool ( *backup );
                *backup = NULL;
        }
 
        return 0;
}

References efi_install_table(), efi_systab, EFI_BOOT_SERVICES::FreePool, NULL, old, and rc.

Referenced by efi_fdt_install(), and efi_fdt_uninstall().