[efi] Raise TPL within EFI_SIMPLE_NETWORK_PROTOCOL entry points

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/interface/efi/efi_snp.c

 static EFI_STATUS EFIAPI
 efi_snp_initialize ( EFI_SIMPLE_NETWORK_PROTOCOL *snp,
 		     UINTN extra_rx_bufsize, UINTN extra_tx_bufsize ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
 	struct efi_snp_device *snpdev =
 		container_of ( snp, struct efi_snp_device, snp );
+	EFI_TPL saved_tpl;
 	int rc;
 
 	DBGC ( snpdev, "SNPDEV %p INITIALIZE (%ld extra RX, %ld extra TX)\n",
 	       ( ( unsigned long ) extra_tx_bufsize ) );
 
 	/* Fail if net device is currently claimed for use by iPXE */
-	if ( efi_snp_claimed )
-		return EFI_NOT_READY;
+	if ( efi_snp_claimed ) {
+		rc = -EAGAIN;
+		goto err_claimed;
+	}
 
+	/* Raise TPL */
+	saved_tpl = bs->RaiseTPL ( TPL_CALLBACK );
+
+	/* Open network device */
 	if ( ( rc = netdev_open ( snpdev->netdev ) ) != 0 ) {
 		DBGC ( snpdev, "SNPDEV %p could not open %s: %s\n",
 		       snpdev, snpdev->netdev->name, strerror ( rc ) );
-		return EFIRC ( rc );
+		goto err_open;
 	}
 	efi_snp_set_state ( snpdev );
 
-	return 0;
+ err_open:
+	bs->RestoreTPL ( saved_tpl );
+ err_claimed:
+	return EFIRC ( rc );
 }
 
 /**
  */
 static EFI_STATUS EFIAPI
 efi_snp_reset ( EFI_SIMPLE_NETWORK_PROTOCOL *snp, BOOLEAN ext_verify ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
 	struct efi_snp_device *snpdev =
 		container_of ( snp, struct efi_snp_device, snp );
+	EFI_TPL saved_tpl;
 	int rc;
 
 	DBGC ( snpdev, "SNPDEV %p RESET (%s extended verification)\n",
 	       snpdev, ( ext_verify ? "with" : "without" ) );
 
 	/* Fail if net device is currently claimed for use by iPXE */
-	if ( efi_snp_claimed )
-		return EFI_NOT_READY;
+	if ( efi_snp_claimed ) {
+		rc = -EAGAIN;
+		goto err_claimed;
+	}
+
+	/* Raise TPL */
+	saved_tpl = bs->RaiseTPL ( TPL_CALLBACK );
 
+	/* Close network device */
 	netdev_close ( snpdev->netdev );
 	efi_snp_set_state ( snpdev );
 	efi_snp_flush ( snpdev );
 
+	/* Reopen network device */
 	if ( ( rc = netdev_open ( snpdev->netdev ) ) != 0 ) {
 		DBGC ( snpdev, "SNPDEV %p could not reopen %s: %s\n",
 		       snpdev, snpdev->netdev->name, strerror ( rc ) );
-		return EFIRC ( rc );
+		goto err_open;
 	}
 	efi_snp_set_state ( snpdev );
 
-	return 0;
+ err_open:
+	bs->RestoreTPL ( saved_tpl );
+ err_claimed:
+	return EFIRC ( rc );
 }
 
 /**
  */
 static EFI_STATUS EFIAPI
 efi_snp_shutdown ( EFI_SIMPLE_NETWORK_PROTOCOL *snp ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
 	struct efi_snp_device *snpdev =
 		container_of ( snp, struct efi_snp_device, snp );
+	EFI_TPL saved_tpl;
 
 	DBGC ( snpdev, "SNPDEV %p SHUTDOWN\n", snpdev );
 
 	if ( efi_snp_claimed )
 		return EFI_NOT_READY;
 
+	/* Raise TPL */
+	saved_tpl = bs->RaiseTPL ( TPL_CALLBACK );
+
+	/* Close network device */
 	netdev_close ( snpdev->netdev );
 	efi_snp_set_state ( snpdev );
 	efi_snp_flush ( snpdev );
 
+	/* Restore TPL */
+	bs->RestoreTPL ( saved_tpl );
+
 	return 0;
 }
 
 static EFI_STATUS EFIAPI
 efi_snp_get_status ( EFI_SIMPLE_NETWORK_PROTOCOL *snp,
 		     UINT32 *interrupts, VOID **txbuf ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
 	struct efi_snp_device *snpdev =
 		container_of ( snp, struct efi_snp_device, snp );
+	EFI_TPL saved_tpl;
 
 	DBGC2 ( snpdev, "SNPDEV %p GET_STATUS", snpdev );
 
 		return EFI_NOT_READY;
 	}
 
+	/* Raise TPL */
+	saved_tpl = bs->RaiseTPL ( TPL_CALLBACK );
+
 	/* Poll the network device */
 	efi_snp_poll ( snpdev );
 
 		DBGC2 ( snpdev, " TX:%p", *txbuf );
 	}
 
+	/* Restore TPL */
+	bs->RestoreTPL ( saved_tpl );
+
 	DBGC2 ( snpdev, "\n" );
 	return 0;
 }
 		   UINTN ll_header_len, UINTN len, VOID *data,
 		   EFI_MAC_ADDRESS *ll_src, EFI_MAC_ADDRESS *ll_dest,
 		   UINT16 *net_proto ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
 	struct efi_snp_device *snpdev =
 		container_of ( snp, struct efi_snp_device, snp );
 	struct ll_protocol *ll_protocol = snpdev->netdev->ll_protocol;
 	struct io_buffer *iobuf;
 	size_t payload_len;
 	unsigned int tx_fill;
+	EFI_TPL saved_tpl;
 	int rc;
 
 	DBGC2 ( snpdev, "SNPDEV %p TRANSMIT %p+%lx", snpdev, data,
 	DBGC2 ( snpdev, "\n" );
 
 	/* Fail if net device is currently claimed for use by iPXE */
-	if ( efi_snp_claimed )
-		return EFI_NOT_READY;
+	if ( efi_snp_claimed ) {
+		rc = -EAGAIN;
+		goto err_claimed;
+	}
+
+	/* Raise TPL */
+	saved_tpl = bs->RaiseTPL ( TPL_CALLBACK );
 
 	/* Sanity checks */
 	if ( ll_header_len ) {
 	snpdev->tx[ snpdev->tx_prod++ % EFI_SNP_NUM_TX ] = data;
 	snpdev->interrupts |= EFI_SIMPLE_NETWORK_TRANSMIT_INTERRUPT;
 
+	/* Restore TPL */
+	bs->RestoreTPL ( saved_tpl );
+
 	return 0;
 
  err_ring_full:
 	free_iob ( iobuf );
  err_alloc_iob:
  err_sanity:
+	bs->RestoreTPL ( saved_tpl );
+ err_claimed:
 	return EFIRC ( rc );
 }
 
 		  UINTN *ll_header_len, UINTN *len, VOID *data,
 		  EFI_MAC_ADDRESS *ll_src, EFI_MAC_ADDRESS *ll_dest,
 		  UINT16 *net_proto ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
 	struct efi_snp_device *snpdev =
 		container_of ( snp, struct efi_snp_device, snp );
 	struct ll_protocol *ll_protocol = snpdev->netdev->ll_protocol;
 	uint16_t iob_net_proto;
 	unsigned int iob_flags;
 	size_t copy_len;
+	EFI_TPL saved_tpl;
 	int rc;
 
 	DBGC2 ( snpdev, "SNPDEV %p RECEIVE %p(+%lx)", snpdev, data,
 		( ( unsigned long ) *len ) );
 
 	/* Fail if net device is currently claimed for use by iPXE */
-	if ( efi_snp_claimed )
-		return EFI_NOT_READY;
+	if ( efi_snp_claimed ) {
+		rc = -EAGAIN;
+		goto err_claimed;
+	}
+
+	/* Raise TPL */
+	saved_tpl = bs->RaiseTPL ( TPL_CALLBACK );
 
 	/* Poll the network device */
 	efi_snp_poll ( snpdev );
  out_bad_ll_header:
 	free_iob ( iobuf );
  out_no_packet:
+	bs->RestoreTPL ( saved_tpl );
+ err_claimed:
 	return EFIRC ( rc );
 }
 
  */
 static VOID EFIAPI efi_snp_wait_for_packet ( EFI_EVENT event __unused,
 					     VOID *context ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
 	struct efi_snp_device *snpdev = context;
+	EFI_TPL saved_tpl;
 
 	DBGCP ( snpdev, "SNPDEV %p WAIT_FOR_PACKET\n", snpdev );
 
 	if ( efi_snp_claimed )
 		return;
 
+	/* Raise TPL */
+	saved_tpl = bs->RaiseTPL ( TPL_CALLBACK );
+
 	/* Poll the network device */
 	efi_snp_poll ( snpdev );
+
+	/* Restore TPL */
+	bs->RestoreTPL ( saved_tpl );
 }
 
 /** SNP interface */