[efi] Add the "snpnet" driver

Add a new network driver that consumes the EFI Simple Network
Protocol.  Also add a bus driver that can find the Simple Network
Protocol that iPXE was loaded from; the resulting behavior is similar
to the "undionly" driver for BIOS systems.

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

10 files changed, 724 insertions, 4 deletions

diff --git a/src/Makefile b/src/Makefile
index 5079f937..f81c4331 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -67,6 +67,7 @@ SRCDIRS		+= drivers/net/phantom
 SRCDIRS		+= drivers/net/rtl818x
 SRCDIRS		+= drivers/net/ath5k
 SRCDIRS		+= drivers/net/vxge
+SRCDIRS		+= drivers/net/efi
 SRCDIRS		+= drivers/block
 SRCDIRS		+= drivers/nvs
 SRCDIRS		+= drivers/bitbash
diff --git a/src/drivers/net/efi/snp.h b/src/drivers/net/efi/snp.h
new file mode 100644
index 00000000..4d6b1014
--- /dev/null
+++ b/src/drivers/net/efi/snp.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2010 VMware, Inc.  All Rights Reserved.
+ *
+ * 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 St, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef _SNP_H
+#define _SNP_H
+
+/** @file
+ *
+ * SNP driver
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <ipxe/device.h>
+#include <ipxe/netdevice.h>
+#include <ipxe/efi/Protocol/SimpleNetwork.h>
+
+/** A network device that consumes the EFI Simple Network Protocol */
+struct snp_device {
+	/** Underlying simple network protocol instance */
+	EFI_SIMPLE_NETWORK_PROTOCOL *snp;
+
+	/** Generic device */
+	struct device dev;
+
+	/** Network device */
+	struct net_device *netdev;
+
+	/** State to put the snp in when removing the device */
+	uint32 removal_state;
+};
+
+#endif /* _SNP_H */
diff --git a/src/drivers/net/efi/snpnet.c b/src/drivers/net/efi/snpnet.c
new file mode 100644
index 00000000..ba63a01d
--- /dev/null
+++ b/src/drivers/net/efi/snpnet.c
@@ -0,0 +1,362 @@
+/*
+ * Copyright (C) 2010 VMware, Inc.  All Rights Reserved.
+ *
+ * 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 St, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <errno.h>
+#include <string.h>
+#include <ipxe/io.h>
+#include <ipxe/iobuf.h>
+#include <ipxe/netdevice.h>
+#include <ipxe/if_ether.h>
+#include <ipxe/ethernet.h>
+#include <ipxe/efi/efi.h>
+#include <ipxe/efi/Protocol/SimpleNetwork.h>
+#include "snp.h"
+#include "snpnet.h"
+
+/** @file
+ *
+ * SNP network device driver
+ *
+ */
+
+/** SNP net device structure */
+struct snpnet_device {
+	/** The underlying simple network protocol */
+	EFI_SIMPLE_NETWORK_PROTOCOL *snp;
+
+	/** State that the SNP should be in after close */
+	UINT32 close_state;
+};
+
+/**
+ * Transmit packet
+ *
+ * @v netdev		Network device
+ * @v iobuf		I/O buffer
+ * @ret rc		Return status code
+ */
+static int snpnet_transmit ( struct net_device *netdev,
+			     struct io_buffer *iobuf ) {
+	struct snpnet_device *snpnetdev = netdev->priv;
+	EFI_SIMPLE_NETWORK_PROTOCOL *snp = snpnetdev->snp;
+	EFI_STATUS efirc;
+	size_t len = iob_len ( iobuf );
+
+	efirc = snp->Transmit ( snp, 0, len, iobuf->data, NULL, NULL, NULL );
+	return EFIRC_TO_RC ( efirc );
+}
+
+/**
+ * Find a I/O buffer on the list of outstanding Tx buffers and complete it.
+ *
+ * @v snpnetdev		SNP network device
+ * @v txbuf		Buffer address
+ */
+static void snpnet_complete ( struct net_device *netdev, void *txbuf ) {
+	struct io_buffer *tmp;
+	struct io_buffer *iobuf;
+
+	list_for_each_entry_safe ( iobuf, tmp, &netdev->tx_queue, list ) {
+		if ( iobuf->data == txbuf ) {
+			netdev_tx_complete ( netdev, iobuf );
+			break;
+		}
+	}
+}
+
+/**
+ * Poll for received packets
+ *
+ * @v netdev		Network device
+ */
+static void snpnet_poll ( struct net_device *netdev ) {
+	struct snpnet_device *snpnetdev = netdev->priv;
+	EFI_SIMPLE_NETWORK_PROTOCOL *snp = snpnetdev->snp;
+	EFI_STATUS efirc;
+	struct io_buffer *iobuf = NULL;
+	UINTN len;
+	void *txbuf;
+
+	/* Process Tx completions */
+	while ( 1 ) {
+		efirc = snp->GetStatus ( snp, NULL, &txbuf );
+		if ( efirc ) {
+			DBGC ( snp, "SNP %p could not get status %s\n", snp,
+			       efi_strerror ( efirc ) );
+			break;
+		}
+
+		if ( txbuf == NULL )
+			break;
+
+		snpnet_complete ( netdev, txbuf );
+	}
+
+	/* Process received packets */
+	while ( 1 ) {
+		/* The spec is not clear if the max packet size refers to the
+		 * payload or the entire packet including headers. The Receive
+		 * function needs a buffer large enough to contain the headers,
+		 * and potentially a 4-byte CRC and 4-byte VLAN tag (?), so add
+		 * some breathing room.
+		 */
+		len = snp->Mode->MaxPacketSize + ETH_HLEN + 8;
+		iobuf = alloc_iob ( len );
+		if ( iobuf == NULL ) {
+			netdev_rx_err ( netdev, NULL, -ENOMEM );
+			break;
+		}
+
+		efirc = snp->Receive ( snp, NULL, &len, iobuf->data,
+				       NULL, NULL, NULL );
+
+		/* No packets left? */
+		if ( efirc == EFI_NOT_READY ) {
+			free_iob ( iobuf );
+			break;
+		}
+
+		/* Other error? */
+		if ( efirc ) {
+			DBGC ( snp, "SNP %p receive packet error: %s "
+				    "(len was %zd, is now %zd)\n",
+			       snp, efi_strerror ( efirc ), iob_len(iobuf),
+			       (size_t)len );
+			netdev_rx_err ( netdev, iobuf, efirc );
+			break;
+		}
+
+		/* Packet is valid, deliver it */
+		iob_put ( iobuf, len );
+		netdev_rx ( netdev, iob_disown ( iobuf ) );
+	}
+}
+
+/**
+ * Open NIC
+ *
+ * @v netdev		Net device
+ * @ret rc		Return status code
+ */
+static int snpnet_open ( struct net_device *netdev ) {
+	struct snpnet_device *snpnetdev = netdev->priv;
+	EFI_SIMPLE_NETWORK_PROTOCOL *snp = snpnetdev->snp;
+	EFI_STATUS efirc;
+	UINT32 enableFlags, disableFlags;
+
+	snpnetdev->close_state = snp->Mode->State;
+	if ( snp->Mode->State != EfiSimpleNetworkInitialized ) {
+		efirc = snp->Initialize ( snp, 0, 0 );
+		if ( efirc ) {
+			DBGC ( snp, "SNP %p could not initialize: %s\n",
+			       snp, efi_strerror ( efirc ) );
+			return EFIRC_TO_RC ( efirc );
+		}
+	}
+
+        /* Use the default MAC address */
+	efirc = snp->StationAddress ( snp, FALSE,
+				      (EFI_MAC_ADDRESS *)netdev->ll_addr );
+	if ( efirc ) {
+		DBGC ( snp, "SNP %p could not reset station address: %s\n",
+		       snp, efi_strerror ( efirc ) );
+	}
+
+	/* Set up receive filters to receive unicast and broadcast packets
+	 * always. Also, enable either promiscuous multicast (if possible) or
+	 * promiscuous operation, in order to catch all multicast packets.
+	 */
+	enableFlags = snp->Mode->ReceiveFilterMask &
+		      ( EFI_SIMPLE_NETWORK_RECEIVE_UNICAST |
+			EFI_SIMPLE_NETWORK_RECEIVE_BROADCAST );
+	disableFlags = snp->Mode->ReceiveFilterMask &
+		       ( EFI_SIMPLE_NETWORK_RECEIVE_MULTICAST |
+			 EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS |
+			 EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS_MULTICAST );
+	if ( snp->Mode->ReceiveFilterMask &
+	     EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS_MULTICAST ) {
+		enableFlags |= EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS_MULTICAST;
+	} else if ( snp->Mode->ReceiveFilterMask &
+		    EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS ) {
+		enableFlags |= EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS;
+	}
+	disableFlags &= ~enableFlags;
+	efirc = snp->ReceiveFilters ( snp, enableFlags, disableFlags,
+				      FALSE, 0, NULL );
+	if ( efirc ) {
+		DBGC ( snp, "SNP %p could not set receive filters: %s\n",
+		       snp, efi_strerror ( efirc ) );
+	}
+
+	DBGC ( snp, "SNP %p opened\n", snp );
+	return 0;
+}
+
+/**
+ * Close NIC
+ *
+ * @v netdev		Net device
+ */
+static void snpnet_close ( struct net_device *netdev ) {
+	struct snpnet_device *snpnetdev = netdev->priv;
+	EFI_SIMPLE_NETWORK_PROTOCOL *snp = snpnetdev->snp;
+	EFI_STATUS efirc;
+
+	if ( snpnetdev->close_state != EfiSimpleNetworkInitialized ) {
+		efirc = snp->Shutdown ( snp );
+		if ( efirc ) {
+			DBGC ( snp, "SNP %p could not shut down: %s\n",
+			       snp, efi_strerror ( efirc ) );
+		}
+	}
+}
+
+/**
+ * Enable/disable interrupts
+ *
+ * @v netdev		Net device
+ * @v enable		Interrupts should be enabled
+ */
+static void snpnet_irq ( struct net_device *netdev, int enable ) {
+	struct snpnet_device *snpnetdev = netdev->priv;
+	EFI_SIMPLE_NETWORK_PROTOCOL *snp = snpnetdev->snp;
+
+	/* On EFI, interrupts are never necessary. (This function is only
+	 * required for BIOS PXE.) If interrupts were required, they could be
+	 * simulated using a fast timer.
+	 */
+	DBGC ( snp, "SNP %p cannot %s interrupts\n",
+	       snp, ( enable ? "enable" : "disable" ) );
+}
+
+/** SNP network device operations */
+static struct net_device_operations snpnet_operations = {
+	.open		= snpnet_open,
+	.close		= snpnet_close,
+	.transmit	= snpnet_transmit,
+	.poll		= snpnet_poll,
+	.irq   		= snpnet_irq,
+};
+
+/**
+ * Probe SNP device
+ *
+ * @v snpdev		SNP device
+ * @ret rc		Return status code
+ */
+int snpnet_probe ( struct snp_device *snpdev ) {
+	EFI_SIMPLE_NETWORK_PROTOCOL *snp = snpdev->snp;
+	EFI_STATUS efirc;
+	struct net_device *netdev;
+	struct snpnet_device *snpnetdev;
+	int rc;
+
+	DBGC ( snp, "SNP %p probing...\n", snp );
+
+	/* Allocate net device */
+	netdev = alloc_etherdev ( sizeof ( struct snpnet_device ) );
+	if ( ! netdev )
+		return -ENOMEM;
+	netdev_init ( netdev, &snpnet_operations );
+	netdev->dev = &snpdev->dev;
+	snpdev->netdev = netdev;
+	snpnetdev = netdev->priv;
+	snpnetdev->snp = snp;
+	snpdev->removal_state = snp->Mode->State;
+
+	/* Start the interface */
+	if ( snp->Mode->State == EfiSimpleNetworkStopped ) {
+		efirc = snp->Start ( snp );
+		if ( efirc ) {
+			DBGC ( snp, "SNP %p could not start: %s\n", snp,
+			       efi_strerror ( efirc ) );
+			rc = EFIRC_TO_RC ( efirc );
+			goto err_start;
+		}
+	}
+
+	if ( snp->Mode->HwAddressSize > sizeof ( netdev->hw_addr ) ) {
+		DBGC ( snp, "SNP %p hardware address is too large\n", snp );
+		rc = -EINVAL;
+		goto err_hwaddr;
+	}
+	memcpy ( netdev->hw_addr, snp->Mode->PermanentAddress.Addr,
+		 snp->Mode->HwAddressSize );
+
+	/* Mark as link up; we don't handle link state */
+	netdev_link_up ( netdev );
+
+	/* Register network device */
+	if ( ( rc = register_netdev ( netdev ) ) != 0 )
+		goto err_register;
+
+	DBGC ( snp, "SNP %p added\n", snp );
+	return 0;
+
+err_register:
+err_hwaddr:
+	if ( snpdev->removal_state == EfiSimpleNetworkStopped )
+		snp->Stop ( snp );
+
+err_start:
+	netdev_nullify ( netdev );
+	netdev_put ( netdev );
+	snpdev->netdev = NULL;
+	return rc;
+}
+
+/**
+ * Remove SNP device
+ *
+ * @v snpdev		SNP device
+ */
+void snpnet_remove ( struct snp_device *snpdev ) {
+	EFI_SIMPLE_NETWORK_PROTOCOL *snp = snpdev->snp;
+	EFI_STATUS efirc;
+	struct net_device *netdev = snpdev->netdev;
+
+	if ( snp->Mode->State == EfiSimpleNetworkInitialized &&
+	     snpdev->removal_state != EfiSimpleNetworkInitialized ) {
+		DBGC ( snp, "SNP %p shutting down\n", snp );
+		efirc = snp->Shutdown ( snp );
+		if ( efirc ) {
+			DBGC ( snp, "SNP %p could not shut down: %s\n",
+			       snp, efi_strerror ( efirc ) );
+		}
+	}
+
+	if ( snp->Mode->State == EfiSimpleNetworkStarted &&
+	     snpdev->removal_state == EfiSimpleNetworkStopped ) {
+		DBGC ( snp, "SNP %p stopping\n", snp );
+		efirc = snp->Stop ( snp );
+		if ( efirc ) {
+			DBGC ( snp, "SNP %p could not be stopped\n", snp );
+		}
+	}
+
+	/* Unregister net device */
+	unregister_netdev ( netdev );
+
+	/* Free network device */
+	netdev_nullify ( netdev );
+	netdev_put ( netdev );
+
+	DBGC ( snp, "SNP %p removed\n", snp );
+}
diff --git a/src/drivers/net/efi/snpnet.h b/src/drivers/net/efi/snpnet.h
new file mode 100644
index 00000000..72b4a7d6
--- /dev/null
+++ b/src/drivers/net/efi/snpnet.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2010 VMware, Inc.  All Rights Reserved.
+ *
+ * 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 St, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef _SNPNET_H
+#define _SNPNET_H
+
+/** @file
+ *
+ * EFI Simple Network Protocol network device driver
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+struct snp_device;
+
+extern int snpnet_probe ( struct snp_device *snpdev );
+extern void snpnet_remove ( struct snp_device *snpdev );
+
+#endif /* _SNPNET_H */
diff --git a/src/drivers/net/efi/snponly.c b/src/drivers/net/efi/snponly.c
new file mode 100644
index 00000000..435ed4fb
--- /dev/null
+++ b/src/drivers/net/efi/snponly.c
@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2010 VMware, Inc.  All Rights Reserved.
+ *
+ * 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 St, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <string.h>
+#include <errno.h>
+#include <ipxe/device.h>
+#include <ipxe/init.h>
+#include <ipxe/efi/efi.h>
+#include <ipxe/efi/Protocol/SimpleNetwork.h>
+#include "snp.h"
+#include "snpnet.h"
+
+/** @file
+ *
+ * Chain-loading Simple Network Protocol Bus Driver
+ *
+ * This bus driver allows iPXE to use the EFI Simple Network Protocol provided
+ * by the platform to transmit and receive packets. It attaches to only the
+ * device handle that iPXE was loaded from, that is, it will only use the
+ * Simple Network Protocol on the current loaded image's device handle.
+ *
+ * Eseentially, this driver provides the EFI equivalent of the "undionly"
+ * driver.
+ */
+
+/** The one and only SNP network device */
+static struct snp_device snponly_dev;
+
+/** EFI simple network protocol GUID */
+static EFI_GUID efi_simple_network_protocol_guid
+	= EFI_SIMPLE_NETWORK_PROTOCOL_GUID;
+
+/**
+ * Probe SNP root bus
+ *
+ * @v rootdev		SNP bus root device
+ *
+ * Look at the loaded image's device handle and see if the simple network
+ * protocol exists. If so, register a driver for it.
+ */
+static int snpbus_probe ( struct root_device *rootdev ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
+	EFI_STATUS efirc;
+	int rc;
+	void *snp;
+
+	efirc = bs->OpenProtocol ( efi_loaded_image->DeviceHandle,
+				   &efi_simple_network_protocol_guid,
+				   &snp, efi_image_handle, NULL,
+				   EFI_OPEN_PROTOCOL_GET_PROTOCOL );
+	if ( efirc ) {
+		DBG ( "Could not find Simple Network Protocol!\n" );
+		return -ENODEV;
+	}
+	snponly_dev.snp = snp;
+
+	/* Add to device hierarchy */
+	strncpy ( snponly_dev.dev.name, "EFI SNP",
+		  ( sizeof ( snponly_dev.dev.name ) - 1 ) );
+	snponly_dev.dev.parent = &rootdev->dev;
+	list_add ( &snponly_dev.dev.siblings, &rootdev->dev.children);
+	INIT_LIST_HEAD ( &snponly_dev.dev.children );
+
+	/* Create network device */
+	if ( ( rc = snpnet_probe ( &snponly_dev ) ) != 0 )
+		goto err;
+
+	return 0;
+
+err:
+	list_del ( &snponly_dev.dev.siblings );
+	return rc;
+}
+
+/**
+ * Remove SNP root bus
+ *
+ * @v rootdev		SNP bus root device
+ */
+static void snpbus_remove ( struct root_device *rootdev __unused ) {
+	snpnet_remove ( &snponly_dev );
+	list_del ( &snponly_dev.dev.siblings );
+}
+
+/** SNP bus root device driver */
+static struct root_driver snp_root_driver = {
+	.probe = snpbus_probe,
+	.remove = snpbus_remove,
+};
+
+/** SNP bus root device */
+struct root_device snp_root_device __root_device = {
+	.dev = { .name = "EFI SNP" },
+	.driver = &snp_root_driver,
+};
+
+/**
+ * Prepare for exit
+ *
+ * @v flags		Shutdown flags
+ */
+static void snponly_shutdown ( int flags ) {
+	/* If we are shutting down to boot an OS, make sure the SNP does not
+	 * stay active.
+	 */
+	if ( flags & SHUTDOWN_BOOT )
+		snponly_dev.removal_state = EfiSimpleNetworkStopped;
+}
+
+struct startup_fn startup_snponly __startup_fn ( STARTUP_LATE ) = {
+	.shutdown = snponly_shutdown,
+};
diff --git a/src/image/efi_image.c b/src/image/efi_image.c
index 6eb943b6..6b6600de 100644
--- a/src/image/efi_image.c
+++ b/src/image/efi_image.c
@@ -21,12 +21,27 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <errno.h>
 #include <ipxe/efi/efi.h>
 #include <ipxe/image.h>
+#include <ipxe/init.h>
 #include <ipxe/features.h>
 
 FEATURE ( FEATURE_IMAGE, "EFI", DHCP_EB_FEATURE_EFI, 1 );
 
 struct image_type efi_image_type __image_type ( PROBE_NORMAL );
 
+/** Event used to signal shutdown */
+static EFI_EVENT efi_shutdown_event;
+
+/**
+ * Shut down in preparation for booting an OS.
+ *
+ * This hook gets called at ExitBootServices time in order to make sure that
+ * the network cards are properly shut down before the OS takes over.
+ */
+static EFIAPI void efi_shutdown_hook ( EFI_EVENT event __unused,
+				       void *context __unused ) {
+	shutdown ( SHUTDOWN_BOOT );
+}
+
 /**
  * Execute EFI image
  *
@@ -39,6 +54,7 @@ static int efi_image_exec ( struct image *image ) {
 	UINTN exit_data_size;
 	CHAR16 *exit_data;
 	EFI_STATUS efirc;
+	int rc;
 
 	/* Attempt loading image */
 	if ( ( efirc = bs->LoadImage ( FALSE, efi_image_handle, NULL,
@@ -50,21 +66,36 @@ static int efi_image_exec ( struct image *image ) {
 		return -ENOEXEC;
 	}
 
+	/* Be sure to shut down the NIC at ExitBootServices time, or else
+	 * DMA from the card can corrupt the OS.
+	 */
+	efirc = bs->CreateEvent ( EVT_SIGNAL_EXIT_BOOT_SERVICES,
+				  TPL_CALLBACK, efi_shutdown_hook,
+				  NULL, &efi_shutdown_event );
+	if ( efirc ) {
+		rc = EFIRC_TO_RC ( efirc );
+		goto done;
+	}
+
 	/* Start the image */
 	if ( ( efirc = bs->StartImage ( handle, &exit_data_size,
 					&exit_data ) ) != 0 ) {
 		DBGC ( image, "EFIIMAGE %p returned with status %s\n",
 		       image, efi_strerror ( efirc ) );
-		goto done;
 	}
 
- done:
+	rc = EFIRC_TO_RC ( efirc );
+
+	/* Remove the shutdown hook */
+	bs->CloseEvent ( efi_shutdown_event );
+
+done:
 	/* Unload the image.  We can't leave it loaded, because we
 	 * have no "unload" operation.
 	 */
 	bs->UnloadImage ( handle );
 
-	return EFIRC_TO_RC ( efirc );
+	return rc;
 }
 
 /**
diff --git a/src/include/ipxe/efi/Protocol/LoadedImage.h b/src/include/ipxe/efi/Protocol/LoadedImage.h
new file mode 100755
index 00000000..12e5e2d7
--- /dev/null
+++ b/src/include/ipxe/efi/Protocol/LoadedImage.h
@@ -0,0 +1,88 @@
+/** @file
+  UEFI 2.0 Loaded image protocol definition.
+
+  Every EFI driver and application is passed an image handle when it is loaded.
+  This image handle will contain a Loaded Image Protocol.
+
+  Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
+  This program and the accompanying materials
+  are licensed and made available under the terms and conditions of the BSD License
+  which accompanies this distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#ifndef __LOADED_IMAGE_PROTOCOL_H__
+#define __LOADED_IMAGE_PROTOCOL_H__
+
+#define EFI_LOADED_IMAGE_PROTOCOL_GUID \
+  { \
+    0x5B1B31A1, 0x9562, 0x11d2, {0x8E, 0x3F, 0x00, 0xA0, 0xC9, 0x69, 0x72, 0x3B } \
+  }
+
+#define EFI_LOADED_IMAGE_DEVICE_PATH_PROTOCOL_GUID \
+  { \
+    0xbc62157e, 0x3e33, 0x4fec, {0x99, 0x20, 0x2d, 0x3b, 0x36, 0xd7, 0x50, 0xdf } \
+  }
+
+///
+/// Protocol GUID defined in EFI1.1.
+///
+#define LOADED_IMAGE_PROTOCOL   EFI_LOADED_IMAGE_PROTOCOL_GUID
+
+///
+/// EFI_SYSTEM_TABLE & EFI_IMAGE_UNLOAD are defined in EfiApi.h
+///
+#define EFI_LOADED_IMAGE_PROTOCOL_REVISION  0x1000
+
+///
+/// Revision defined in EFI1.1.
+///
+#define EFI_LOADED_IMAGE_INFORMATION_REVISION    EFI_LOADED_IMAGE_PROTOCOL_REVISION
+
+///
+/// Can be used on any image handle to obtain information about the loaded image.
+///
+typedef struct {
+  UINT32            Revision;       ///< Defines the revision of the EFI_LOADED_IMAGE_PROTOCOL structure.
+                                    ///< All future revisions will be backward compatible to the current revision.
+  EFI_HANDLE        ParentHandle;   ///< Parent image's image handle. NULL if the image is loaded directly from
+                                    ///< the firmware's boot manager.
+  EFI_SYSTEM_TABLE  *SystemTable;   ///< the image's EFI system table pointer.
+
+  //
+  // Source location of image
+  //
+  EFI_HANDLE        DeviceHandle;   ///< The device handle that the EFI Image was loaded from.
+  EFI_DEVICE_PATH_PROTOCOL  *FilePath;  ///< A pointer to the file path portion specific to DeviceHandle
+                                        ///< that the EFI Image was loaded from.
+  VOID              *Reserved;      ///< Reserved. DO NOT USE.
+
+  //
+  // Images load options
+  //
+  UINT32            LoadOptionsSize;///< The size in bytes of LoadOptions.
+  VOID              *LoadOptions;   ///< A pointer to the image's binary load options.
+
+  //
+  // Location of where image was loaded
+  //
+  VOID              *ImageBase;     ///< The base address at which the image was loaded.
+  UINT64            ImageSize;      ///< The size in bytes of the loaded image.
+  EFI_MEMORY_TYPE   ImageCodeType;  ///< The memory type that the code sections were loaded as.
+  EFI_MEMORY_TYPE   ImageDataType;  ///< The memory type that the data sections were loaded as.
+  EFI_IMAGE_UNLOAD  Unload;
+} EFI_LOADED_IMAGE_PROTOCOL;
+
+//
+// For backward-compatible with EFI1.1.
+//
+typedef EFI_LOADED_IMAGE_PROTOCOL EFI_LOADED_IMAGE;
+
+extern EFI_GUID gEfiLoadedImageProtocolGuid;
+extern EFI_GUID gEfiLoadedImageDevicePathProtocolGuid;
+
+#endif
diff --git a/src/include/ipxe/efi/efi.h b/src/include/ipxe/efi/efi.h
index 639d7990..6dca1324 100644
--- a/src/include/ipxe/efi/efi.h
+++ b/src/include/ipxe/efi/efi.h
@@ -42,6 +42,7 @@
 /* Include the top-level EFI header files */
 #include <ipxe/efi/Uefi.h>
 #include <ipxe/efi/PiDxe.h>
+#include <ipxe/efi/Protocol/LoadedImage.h>
 
 /* Reset any trailing #pragma pack directives */
 #pragma pack(1)
@@ -135,6 +136,7 @@ struct efi_config_table {
 #define EFIRC_TO_RC( efirc ) (efirc)
 
 extern EFI_HANDLE efi_image_handle;
+extern EFI_LOADED_IMAGE_PROTOCOL *efi_loaded_image;
 extern EFI_SYSTEM_TABLE *efi_systab;
 
 extern const char * efi_strerror ( EFI_STATUS efirc );
diff --git a/src/include/ipxe/errfile.h b/src/include/ipxe/errfile.h
index 2bb655fd..b8a8a8cc 100644
--- a/src/include/ipxe/errfile.h
+++ b/src/include/ipxe/errfile.h
@@ -123,6 +123,8 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #define ERRFILE_vxge_config	     ( ERRFILE_DRIVER | 0x00560000 )
 #define ERRFILE_vxge_traffic	     ( ERRFILE_DRIVER | 0x00570000 )
 #define ERRFILE_igb_main	     ( ERRFILE_DRIVER | 0x00580000 )
+#define ERRFILE_snpnet		     ( ERRFILE_DRIVER | 0x00590000 )
+#define ERRFILE_snponly		     ( ERRFILE_DRIVER | 0x005a0000 )
 
 #define ERRFILE_scsi		     ( ERRFILE_DRIVER | 0x00700000 )
 #define ERRFILE_arbel		     ( ERRFILE_DRIVER | 0x00710000 )
diff --git a/src/interface/efi/efi_init.c b/src/interface/efi/efi_init.c
index ed659932..029bc06f 100644
--- a/src/interface/efi/efi_init.c
+++ b/src/interface/efi/efi_init.c
@@ -20,14 +20,22 @@ FILE_LICENCE ( GPL2_OR_LATER );
 
 #include <string.h>
 #include <ipxe/efi/efi.h>
+#include <ipxe/efi/Protocol/LoadedImage.h>
 #include <ipxe/uuid.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;
+
 /** System table passed to entry point */
 EFI_SYSTEM_TABLE *efi_systab;
 
+/** EFI loaded image protocol GUID */
+static EFI_GUID efi_loaded_image_protocol_guid
+	= EFI_LOADED_IMAGE_PROTOCOL_GUID;
+
 /**
  * Look up EFI configuration table
  *
@@ -59,6 +67,7 @@ EFI_STATUS efi_init ( EFI_HANDLE image_handle,
 	struct efi_protocol *prot;
 	struct efi_config_table *tab;
 	EFI_STATUS efirc;
+	void *loaded_image;
 
 	/* Store image handle and system table pointer for future use */
 	efi_image_handle = image_handle;
@@ -80,8 +89,20 @@ EFI_STATUS efi_init ( EFI_HANDLE image_handle,
 	}
 	DBGC ( systab, "EFI handle %p systab %p\n", image_handle, systab );
 
-	/* Look up used protocols */
 	bs = systab->BootServices;
+	efirc = bs->OpenProtocol ( image_handle,
+				   &efi_loaded_image_protocol_guid,
+				   &loaded_image, image_handle, NULL,
+				   EFI_OPEN_PROTOCOL_GET_PROTOCOL );
+	if ( efirc ) {
+	   DBGC ( systab, "Could not get loaded image protocol" );
+	   return efirc;
+	}
+
+	efi_loaded_image = loaded_image;
+	DBG ( "Image base address = %p\n", efi_loaded_image->ImageBase );
+
+	/* Look up used protocols */
 	for_each_table_entry ( prot, EFI_PROTOCOLS ) {
 		if ( ( efirc = bs->LocateProtocol ( &prot->u.guid, NULL,
 						    prot->protocol ) ) == 0 ) {