[init] Remove concept of "shutdown exit flags"

Remove the concept of shutdown exit flags, and replace it with a
counter used to keep track of exposed interfaces that require devices
to remain active.

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

src/arch/i386/drivers/net/undionly.c

@@ -114,13 +114,13 @@ struct root_device undi_root_device __root_device = {
 /**
  * Prepare for exit
  *
- * @v flags		Shutdown flags
+ * @v booting		System is shutting down for OS boot
  */
-static void undionly_shutdown ( int flags ) {
+static void undionly_shutdown ( int booting ) {
 	/* If we are shutting down to boot an OS, clear the "keep PXE
 	 * stack" flag.
 	 */
-	if ( flags & SHUTDOWN_BOOT )
+	if ( booting )
 		preloaded_undi.flags &= ~UNDI_FL_KEEP_ALL;
 }
 

src/arch/i386/image/bzimage.c

@@ -477,7 +477,7 @@ static int bzimage_exec ( struct image *image ) {
 	bzimage_update_header ( image, &bzimg, bzimg.rm_kernel );
 
 	/* Prepare for exiting */
-	shutdown ( SHUTDOWN_BOOT );
+	shutdown_boot();
 
 	DBGC ( image, "bzImage %p jumping to RM kernel at %04x:0000 "
 	       "(stack %04x:%04zx)\n", image, ( bzimg.rm_kernel_seg + 0x20 ),

src/arch/i386/image/elfboot.c

@@ -48,7 +48,7 @@ static int elfboot_exec ( struct image *image ) {
 	/* An ELF image has no callback interface, so we need to shut
 	 * down before invoking it.
 	 */
-	shutdown ( SHUTDOWN_BOOT );
+	shutdown_boot();
 
 	/* Jump to OS with flat physical addressing */
 	DBGC ( image, "ELF %p starting execution at %lx\n", image, entry );

src/arch/i386/image/multiboot.c

@@ -278,7 +278,7 @@ static int multiboot_exec ( struct image *image ) {
 	/* Multiboot images may not return and have no callback
 	 * interface, so shut everything down prior to booting the OS.
 	 */
-	shutdown ( SHUTDOWN_BOOT );
+	shutdown_boot();
 
 	/* Build memory map after unhiding bootloader memory regions as part of
 	 * shutting everything down.

src/arch/i386/image/nbi.c

@@ -406,7 +406,7 @@ static int nbi_exec ( struct image *image ) {
 	/* Shut down now if NBI image will not return */
 	may_return = NBI_PROGRAM_RETURNS ( imgheader.flags );
 	if ( ! may_return )
-		shutdown ( SHUTDOWN_BOOT );
+		shutdown_boot();
 
 	/* Execute NBI image */
 	if ( NBI_LINEAR_EXEC_ADDR ( imgheader.flags ) ) {

src/arch/i386/interface/pcbios/int13.c

@@ -1209,8 +1209,10 @@ static int int13_hook ( struct uri *uri, unsigned int drive ) {
 	       int13->cylinders, int13->heads, int13->sectors_per_track );
 
 	/* Hook INT 13 vector if not already hooked */
-	if ( list_empty ( &int13s ) )
+	if ( list_empty ( &int13s ) ) {
 		int13_hook_vector();
+		devices_get();
+	}
 
 	/* Add to list of emulated drives */
 	list_add ( &int13->list, &int13s );
@@ -1277,8 +1279,10 @@ static void int13_unhook ( unsigned int drive ) {
 	DBGC ( int13, "INT13 drive %02x unregistered\n", int13->drive );
 
 	/* Unhook INT 13 vector if no more drives */
-	if ( list_empty ( &int13s ) )
+	if ( list_empty ( &int13s ) ) {
+		devices_put();
 		int13_unhook_vector();
+	}
 
 	/* Drop list's reference to drive */
 	ref_put ( &int13->refcnt );

src/arch/i386/interface/pxe/pxe_call.c

@@ -448,6 +448,7 @@ void pxe_activate ( struct net_device *netdev ) {
 	if ( ! int_1a_hooked ) {
 		hook_bios_interrupt ( 0x1a, ( unsigned int ) pxe_int_1a,
 				      &pxe_int_1a_vector );
+		devices_get();
 		int_1a_hooked = 1;
 	}
 
@@ -475,6 +476,7 @@ int pxe_deactivate ( void ) {
 			      strerror ( rc ) );
 			return rc;
 		}
+		devices_put();
 		int_1a_hooked = 0;
 	}
 

src/arch/i386/interface/pxe/pxe_preboot.c

@@ -290,7 +290,7 @@ PXENV_EXIT_t pxenv_stop_undi ( struct s_PXENV_STOP_UNDI *stop_undi ) {
 	pxe_deactivate();
 
 	/* Prepare for unload */
-	shutdown ( SHUTDOWN_BOOT );
+	shutdown_boot();
 
 	/* Check to see if we still have any hooked interrupts */
 	if ( hooked_bios_interrupts != 0 ) {

src/arch/i386/interface/syslinux/comboot_call.c

@@ -531,7 +531,7 @@ static __asmcall void int22 ( struct i386_all_regs *ix86 ) {
 			break;
 
 		/* Perform final cleanup */
-		shutdown ( SHUTDOWN_BOOT );
+		shutdown_boot();
 
 		/* Perform sequence of copies */
 		shuffle ( ix86->segs.es, ix86->regs.di, ix86->regs.cx );
@@ -608,7 +608,7 @@ static __asmcall void int22 ( struct i386_all_regs *ix86 ) {
 			break;
 
 		/* Perform final cleanup */
-		shutdown ( SHUTDOWN_BOOT );
+		shutdown_boot();
 
 		/* Perform sequence of copies */
 		shuffle ( ix86->segs.es, ix86->regs.di, ix86->regs.cx );