diff options
Diffstat (limited to 'src/interface/efi/efi_init.c')
| -rw-r--r-- | src/interface/efi/efi_init.c | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/src/interface/efi/efi_init.c b/src/interface/efi/efi_init.c index 1c6e9d440..5d98f9ff7 100644 --- a/src/interface/efi/efi_init.c +++ b/src/interface/efi/efi_init.c @@ -47,6 +47,9 @@ EFI_DEVICE_PATH_PROTOCOL *efi_loaded_image_path; */ 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; @@ -79,6 +82,17 @@ static EFI_STATUS EFIAPI efi_unload ( EFI_HANDLE image_handle ); 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. */ @@ -273,7 +287,7 @@ EFI_STATUS efi_init ( EFI_HANDLE image_handle, * bother doing so when ExitBootServices() is called. */ if ( ( efirc = bs->CreateEvent ( EVT_SIGNAL_EXIT_BOOT_SERVICES, - TPL_CALLBACK, efi_shutdown_hook, + TPL_NOTIFY, efi_shutdown_hook, NULL, &efi_shutdown_event ) ) != 0 ) { rc = -EEFI ( efirc ); DBGC ( systab, "EFI could not create ExitBootServices event: " @@ -373,7 +387,7 @@ __attribute__ (( noreturn )) void __stack_chk_fail ( void ) { } /** - * Raise task priority level to TPL_CALLBACK + * Raise task priority level to internal level * * @v tpl Saved TPL */ @@ -384,7 +398,7 @@ void efi_raise_tpl ( struct efi_saved_tpl *tpl ) { tpl->previous = efi_external_tpl; /* Raise TPL and record previous TPL as new external TPL */ - tpl->current = bs->RaiseTPL ( TPL_CALLBACK ); + tpl->current = bs->RaiseTPL ( efi_internal_tpl ); efi_external_tpl = tpl->current; } |