/* * Copyright (C) 2008 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 * 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 #include #include #include #include #include #include #include #include #include /** 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 ); }