/*
* Copyright (C) 2008 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
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* 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 Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <string.h>
#include <errno.h>
#include <endian.h>
#include <ipxe/init.h>
#include <ipxe/rotate.h>
#include <ipxe/efi/efi.h>
#include <ipxe/efi/efi_driver.h>
#include <ipxe/efi/efi_path.h>
#include <ipxe/efi/efi_cmdline.h>
#include <ipxe/efi/Protocol/LoadedImage.h>
/** Image handle passed to entry point */
EFI_HANDLE efi_image_handle;
/** Loaded image protocol for this image */
EFI_LOADED_IMAGE_PROTOCOL *efi_loaded_image;
/** Device path for the loaded image's device handle */
EFI_DEVICE_PATH_PROTOCOL *efi_loaded_image_path;
/** System table passed to entry point
*
* We construct the symbol name efi_systab via the PLATFORM macro.
* This ensures that the symbol is defined only in EFI builds, and so
* prevents EFI code from being incorrectly linked in to a non-EFI
* build.
*/
EFI_SYSTEM_TABLE * _C2 ( PLATFORM, _systab );
/** Internal task priority level */
EFI_TPL efi_internal_tpl = TPL_CALLBACK;
/** External task priority level */
EFI_TPL efi_external_tpl = TPL_APPLICATION;
/** EFI shutdown is in progress */
int efi_shutdown_in_progress;
/** Event used to signal shutdown */
static EFI_EVENT efi_shutdown_event;
/** Stack cookie */
unsigned long __stack_chk_guard;
/** Exit function
*
* Cached to minimise external dependencies when a stack check
* failure is triggered.
*/
static EFI_EXIT efi_exit;
/* Forward declarations */
static EFI_STATUS EFIAPI efi_unload ( EFI_HANDLE image_handle );
/**
* Shut down in preparation for booting an OS.
*
* This hook gets called at ExitBootServices time in order to make
* sure that everything is properly shut down before the OS takes
* over.
*/
static EFIAPI void efi_shutdown_hook ( EFI_EVENT event __unused,
void *context __unused ) {
/* This callback is invoked at TPL_NOTIFY in order to ensure
* that we have an opportunity to shut down cleanly before
* other shutdown hooks perform destructive operations such as
* disabling the IOMMU.
*
* Modify the internal task priority level so that no code
* attempts to raise from TPL_NOTIFY to TPL_CALLBACK (which
* would trigger a fatal exception).
*/
efi_internal_tpl = TPL_NOTIFY;
/* Mark shutdown as being in progress, to indicate that large
* parts of the system (e.g. timers) are no longer functional.
*/
efi_shutdown_in_progress = 1;
/* Shut down iPXE */
shutdown_boot();
}
/**
* Look up EFI configuration table
*
* @v guid Configuration table GUID
* @ret table Configuration table, or NULL
*/
static void * efi_find_table ( EFI_GUID *guid ) {
unsigned int i;
for ( i = 0 ; i < efi_systab->NumberOfTableEntries ; i++ ) {
if ( memcmp ( &efi_systab->ConfigurationTable[i].VendorGuid,
guid, sizeof ( *guid ) ) == 0 )
return efi_systab->ConfigurationTable[i].VendorTable;
}
return NULL;
}
/**
* Construct a stack cookie value
*
* @v handle Image handle
* @ret cookie Stack cookie
*/
__attribute__ (( noinline )) unsigned long
efi_stack_cookie ( EFI_HANDLE handle ) {
unsigned long cookie = 0;
unsigned int rotation = ( 8 * sizeof ( cookie ) / 4 );
/* There is no viable source of entropy available at this
* point. Construct a value that is at least likely to vary
* between platforms and invocations.
*/
cookie ^= ( ( unsigned long ) handle );
cookie = roll ( cookie, rotation );
cookie ^= ( ( unsigned long ) &handle );
cookie = roll ( cookie, rotation );
cookie ^= profile_timestamp();
cookie = roll ( cookie, rotation );
cookie ^= build_id;
/* Ensure that the value contains a NUL byte, to act as a
* runaway string terminator. Construct the NUL using a shift
* rather than a mask, to avoid losing valuable entropy in the
* lower-order bits.
*/
cookie <<= 8;
/* Ensure that the NUL byte is placed at the bottom of the
* stack cookie, to avoid potential disclosure via an
* unterminated string.
*/
if ( __BYTE_ORDER == __BIG_ENDIAN )
cookie >>= 8;
return cookie;
}
/**
* Initialise EFI environment
*
* @v image_handle Image handle
* @v systab System table
* @ret efirc EFI return status code
*/
EFI_STATUS efi_init ( EFI_HANDLE image_handle,
EFI_SYSTEM_TABLE *systab ) {
EFI_BOOT_SERVICES *bs;
struct efi_protocol *prot;
struct efi_config_table *tab;
void *loaded_image;
void *device_path;
void *device_path_copy;
size_t device_path_len;
EFI_STATUS efirc;
int rc;
/* Store image handle and system table pointer for future use */
efi_image_handle = image_handle;
efi_systab = systab;
/* Sanity checks */
if ( ! systab ) {
efirc = EFI_NOT_AVAILABLE_YET;
goto err_sanity;
}
if ( ! systab->ConOut ) {
efirc = EFI_NOT_AVAILABLE_YET;
goto err_sanity;
}
if ( ! systab->BootServices ) {
DBGC ( systab, "EFI provided no BootServices entry point\n" );
efirc = EFI_NOT_AVAILABLE_YET;
goto err_sanity;
}
if ( ! systab->RuntimeServices ) {
DBGC ( systab, "EFI provided no RuntimeServices entry "
"point\n" );
efirc = EFI_NOT_AVAILABLE_YET;
goto err_sanity;
}
DBGC ( systab, "EFI handle %p systab %p\n", image_handle, systab );
bs = systab->BootServices;
/* Store abort function pointer */
efi_exit = bs->Exit;
/* Look up used protocols */
for_each_table_entry ( prot, EFI_PROTOCOLS ) {
if ( ( efirc = bs->LocateProtocol ( &prot->guid, NULL,
prot->protocol ) ) == 0 ) {
DBGC ( systab, "EFI protocol %s is at %p\n",
efi_guid_ntoa ( &prot->guid ),
*(prot->protocol) );
} else {
DBGC ( systab, "EFI does not provide protocol %s\n",
efi_guid_ntoa ( &prot->guid ) );
/* Fail if protocol is required */
if ( prot->required )
goto err_missing_protocol;
}
}
/* Look up used configuration tables */
for_each_table_entry ( tab, EFI_CONFIG_TABLES ) {
if ( ( *(tab->table) = efi_find_table ( &tab->guid ) ) ) {
DBGC ( systab, "EFI configuration table %s is at %p\n",
efi_guid_ntoa ( &tab->guid ), *(tab->table) );
} else {
DBGC ( systab, "EFI does not provide configuration "
"table %s\n", efi_guid_ntoa ( &tab->guid ) );
if ( tab->required ) {
efirc = EFI_NOT_AVAILABLE_YET;
goto err_missing_table;
}
}
}
/* Get loaded image protocol */
if ( ( efirc = bs->OpenProtocol ( image_handle,
&efi_loaded_image_protocol_guid,
&loaded_image, image_handle, NULL,
EFI_OPEN_PROTOCOL_GET_PROTOCOL ) ) != 0 ) {
rc = -EEFI ( efirc );
DBGC ( systab, "EFI could not get loaded image protocol: %s",
strerror ( rc ) );
goto err_no_loaded_image;
}
efi_loaded_image = loaded_image;
DBGC ( systab, "EFI image base address %p\n",
efi_loaded_image->ImageBase );
/* Record command line */
efi_cmdline = efi_loaded_image->LoadOptions;
efi_cmdline_len = efi_loaded_image->LoadOptionsSize;
/* Get loaded image's device handle's device path */
if ( ( efirc = bs->OpenProtocol ( efi_loaded_image->DeviceHandle,
&efi_device_path_protocol_guid,
&device_path, image_handle, NULL,
EFI_OPEN_PROTOCOL_GET_PROTOCOL ) ) != 0 ) {
rc = -EEFI ( efirc );
DBGC ( systab, "EFI could not get loaded image's device path: "
"%s", strerror ( rc ) );
goto err_no_device_path;
}
/* Make a copy of the loaded image's device handle's device
* path, since the device handle itself may become invalidated
* when we load our own drivers.
*/
device_path_len = ( efi_path_len ( device_path ) +
sizeof ( EFI_DEVICE_PATH_PROTOCOL ) );
if ( ( efirc = bs->AllocatePool ( EfiBootServicesData, device_path_len,
&device_path_copy ) ) != 0 ) {
rc = -EEFI ( efirc );
goto err_alloc_device_path;
}
memcpy ( device_path_copy, device_path, device_path_len );
efi_loaded_image_path = device_path_copy;
DBGC ( systab, "EFI image device path %s\n",
efi_devpath_text ( efi_loaded_image_path ) );
/* EFI is perfectly capable of gracefully shutting down any
* loaded devices if it decides to fall back to a legacy boot.
* For no particularly comprehensible reason, it doesn't
* bother doing so when ExitBootServices() is called.
*/
if ( ( efirc = bs->CreateEvent ( EVT_SIGNAL_EXIT_BOOT_SERVICES,
TPL_NOTIFY, efi_shutdown_hook,
NULL, &efi_shutdown_event ) ) != 0 ) {
rc = -EEFI ( efirc );
DBGC ( systab, "EFI could not create ExitBootServices event: "
"%s\n", strerror ( rc ) );
goto err_create_event;
}
/* Install driver binding protocol */
if ( ( rc = efi_driver_install() ) != 0 ) {
DBGC ( systab, "EFI could not install driver: %s\n",
strerror ( rc ) );
efirc = EFIRC ( rc );
goto err_driver_install;
}
/* Install image unload method */
efi_loaded_image->Unload = efi_unload;
return 0;
efi_driver_uninstall();
err_driver_install:
bs->CloseEvent ( efi_shutdown_event );
err_create_event:
bs->FreePool ( efi_loaded_image_path );
err_alloc_device_path:
err_no_device_path:
err_no_loaded_image:
err_missing_table:
err_missing_protocol:
err_sanity:
return efirc;
}
/**
* Shut down EFI environment
*
* @v image_handle Image handle
*/
static EFI_STATUS EFIAPI efi_unload ( EFI_HANDLE image_handle __unused ) {
EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
EFI_SYSTEM_TABLE *systab = efi_systab;
struct efi_saved_tpl tpl;
DBGC ( systab, "EFI image unloading\n" );
/* Raise TPL */
efi_raise_tpl ( &tpl );
/* Shut down */
shutdown_exit();
/* Disconnect any remaining devices */
efi_driver_disconnect_all();
/* Uninstall driver binding protocol */
efi_driver_uninstall();
/* Uninstall exit boot services event */
bs->CloseEvent ( efi_shutdown_event );
/* Free copy of loaded image's device handle's device path */
bs->FreePool ( efi_loaded_image_path );
DBGC ( systab, "EFI image unloaded\n" );
/* Restore TPL */
efi_restore_tpl ( &tpl );
return 0;
}
/**
* Abort on stack check failure
*
*/
__attribute__ (( noreturn )) void __stack_chk_fail ( void ) {
EFI_STATUS efirc;
int rc;
/* Report failure (when debugging) */
DBGC ( efi_systab, "EFI stack check failed (cookie %#lx); aborting\n",
__stack_chk_guard );
/* Attempt to exit cleanly with an error status */
if ( efi_exit ) {
efirc = efi_exit ( efi_image_handle, EFI_COMPROMISED_DATA,
0, NULL );
rc = -EEFI ( efirc );
DBGC ( efi_systab, "EFI stack check exit failed: %s\n",
strerror ( rc ) );
}
/* If the exit fails for any reason, lock the system */
while ( 1 ) {}
}
/**
* Raise task priority level to internal level
*
* @v tpl Saved TPL
*/
void efi_raise_tpl ( struct efi_saved_tpl *tpl ) {
EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
/* Record current external TPL */
tpl->previous = efi_external_tpl;
/* Raise TPL and record previous TPL as new external TPL */
tpl->current = bs->RaiseTPL ( efi_internal_tpl );
efi_external_tpl = tpl->current;
}
/**
* Restore task priority level
*
* @v tpl Saved TPL
*/
void efi_restore_tpl ( struct efi_saved_tpl *tpl ) {
EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
/* Restore external TPL */
efi_external_tpl = tpl->previous;
/* Restore TPL */
bs->RestoreTPL ( tpl->current );
}
