[undi] Allocate base memory before calling UNDI loader entry point

Allocate base memory (by decreasing the free base memory counter)
before calling the UNDI loader entry point, to minimise surprises for
the UNDI loader code.

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

src/arch/x86/drivers/net/undiload.c

@@ -72,7 +72,8 @@ int undi_load ( struct undi_device *undi, struct undi_rom *undirom ) {
 	/* Only one UNDI instance may be loaded at any given time */
 	if ( undi_loader_entry.segment ) {
 		DBG ( "UNDI %p cannot load multiple instances\n", undi );
-		return -EBUSY;
+		rc = -EBUSY;
+		goto err_multiple;
 	}
 
 	/* Set up START_UNDI parameters */
@@ -90,10 +91,15 @@ int undi_load ( struct undi_device *undi, struct undi_rom *undirom ) {
 	undi_loader.UNDI_CS = fbms_seg;
 	fbms_seg -= ( ( undirom->data_size + 0x0f ) >> 4 );
 	undi_loader.UNDI_DS = fbms_seg;
+	undi->fbms = ( fbms_seg >> 6 );
+	set_fbms ( undi->fbms );
+	DBGC ( undi, "UNDI %p allocated [%d,%d) kB of base memory\n",
+	       undi, undi->fbms, undi->restore_fbms );
 
 	/* Debug info */
-	DBGC ( undi, "UNDI %p loading UNDI ROM %p to CS %04x DS %04x for ",
-	       undi, undirom, undi_loader.UNDI_CS, undi_loader.UNDI_DS );
+	DBGC ( undi, "UNDI %p loading ROM %p to CS %04x:%04zx DS %04x:%04zx "
+	       "for ", undi, undirom, undi_loader.UNDI_CS, undirom->code_size,
+	       undi_loader.UNDI_DS, undirom->data_size );
 	if ( undi->pci_busdevfn != UNDI_NO_PCI_BUSDEVFN ) {
 		unsigned int bus = ( undi->pci_busdevfn >> 8 );
 		unsigned int devfn = ( undi->pci_busdevfn & 0xff );
@@ -116,15 +122,11 @@ int undi_load ( struct undi_device *undi, struct undi_rom *undirom ) {
 			       : "=a" ( exit )
 			       : "a" ( __from_data16 ( &undi_loader ) )
 			       : "ebx", "ecx", "edx", "esi", "edi" );
-
 	if ( exit != PXENV_EXIT_SUCCESS ) {
-		/* Clear entry point */
-		memset ( &undi_loader_entry, 0, sizeof ( undi_loader_entry ) );
-
 		rc = -EUNDILOAD ( undi_loader.Status );
 		DBGC ( undi, "UNDI %p loader failed: %s\n",
 		       undi, strerror ( rc ) );
-		return rc;
+		goto err_loader;
 	}
 
 	/* Populate PXE device structure */
@@ -138,13 +140,13 @@ int undi_load ( struct undi_device *undi, struct undi_rom *undirom ) {
 	       undi->pxenv.offset, undi->ppxe.segment, undi->ppxe.offset,
 	       undi->entry.segment, undi->entry.offset );
 
-	/* Update free base memory counter */
-	undi->fbms = ( fbms_seg >> 6 );
-	set_fbms ( undi->fbms );
-	DBGC ( undi, "UNDI %p using [%d,%d) kB of base memory\n",
-	       undi, undi->fbms, undi->restore_fbms );
-
 	return 0;
+
+ err_loader:
+	set_fbms ( undi->restore_fbms );
+	memset ( &undi_loader_entry, 0, sizeof ( undi_loader_entry ) );
+ err_multiple:
+	return rc;
 }
 
 /**