[i386] Change semantics of __from_data16 and __from_text16

__from_data16 and __from_text16 now take a pointer to a
.data16/.text16 variable, and return the real-mode offset within the
appropriate segment.  This matches the use case for every occurrence
of these macros, and prevents potential future bugs such as that fixed
in commit d51d80f.  (The bug arose essentially because "&pointer" is
still syntactically valid.)

6 files changed, 19 insertions, 22 deletions

diff --git a/src/arch/i386/drivers/net/undiload.c b/src/arch/i386/drivers/net/undiload.c
index a3284f802..dbd9e7c20 100644
--- a/src/arch/i386/drivers/net/undiload.c
+++ b/src/arch/i386/drivers/net/undiload.c
@@ -93,8 +93,8 @@ int undi_load ( struct undi_device *undi, struct undi_rom *undirom ) {
 					   "lcall *%c2\n\t"
 					   "addw $4, %%sp\n\t" )
 			       : "=a" ( exit )
-			       : "a" ( & __from_data16 ( undi_loader ) ),
-			         "p" ( & __from_data16 ( undi_loader_entry ) )
+			       : "a" ( __from_data16 ( &undi_loader ) ),
+			         "p" ( __from_data16 ( &undi_loader_entry ) )
 			       : "ebx", "ecx", "edx", "esi", "edi", "ebp" );
 
 	/* UNDI API calls may rudely change the status of A20 and not
diff --git a/src/arch/i386/drivers/net/undinet.c b/src/arch/i386/drivers/net/undinet.c
index 09c29abae..12b954c07 100644
--- a/src/arch/i386/drivers/net/undinet.c
+++ b/src/arch/i386/drivers/net/undinet.c
@@ -176,9 +176,9 @@ static int undinet_call ( struct undi_nic *undinic, unsigned int function,
 					   "addw $6, %%sp\n\t" )
 			       : "=a" ( exit ), "=b" ( discard_b ),
 			         "=D" ( discard_D )
-			       : "p" ( &__from_data16 ( undinet_entry_point )),
+			       : "p" ( __from_data16 ( &undinet_entry_point )),
 			         "b" ( function ),
-			         "D" ( &__from_data16 ( undinet_params ) )
+			         "D" ( __from_data16 ( &undinet_params ) )
 			       : "ecx", "edx", "esi", "ebp" );
 
 	/* UNDI API calls may rudely change the status of A20 and not
@@ -211,7 +211,7 @@ static int undinet_call ( struct undi_nic *undinic, unsigned int function,
 	if ( rc != 0 ) {
 		SEGOFF16_t rm_params = {
 			.segment = rm_ds,
-			.offset = (intptr_t) &__from_data16 ( undinet_params ),
+			.offset = __from_data16 ( &undinet_params ),
 		};
 
 		DBGC ( undinic, "UNDINIC %p %s failed: %s\n", undinic,
@@ -357,17 +357,14 @@ static int undinet_transmit ( struct net_device *netdev,
 	/* Create PXENV_UNDI_TRANSMIT data structure */
 	memset ( &undi_transmit, 0, sizeof ( undi_transmit ) );
 	undi_transmit.DestAddr.segment = rm_ds;
-	undi_transmit.DestAddr.offset
-		= ( ( unsigned ) & __from_data16 ( undinet_tbd ) );
+	undi_transmit.DestAddr.offset = __from_data16 ( &undinet_tbd );
 	undi_transmit.TBD.segment = rm_ds;
-	undi_transmit.TBD.offset
-		= ( ( unsigned ) & __from_data16 ( undinet_tbd ) );
+	undi_transmit.TBD.offset = __from_data16 ( &undinet_tbd );
 
 	/* Create PXENV_UNDI_TBD data structure */
 	undinet_tbd.ImmedLength = len;
 	undinet_tbd.Xmit.segment = rm_ds;
-	undinet_tbd.Xmit.offset 
-		= ( ( unsigned ) & __from_data16 ( basemem_packet ) );
+	undinet_tbd.Xmit.offset = __from_data16 ( basemem_packet );
 
 	/* Issue PXE API call */
 	if ( ( rc = undinet_call ( undinic, PXENV_UNDI_TRANSMIT,
diff --git a/src/arch/i386/firmware/pcbios/memmap.c b/src/arch/i386/firmware/pcbios/memmap.c
index b6a8ca3c7..97d4861dc 100644
--- a/src/arch/i386/firmware/pcbios/memmap.c
+++ b/src/arch/i386/firmware/pcbios/memmap.c
@@ -147,7 +147,7 @@ static int meme820 ( struct memory_map *memmap ) {
 					 "=b" ( next ), "=D" ( discard_D ),
 					 "=c" ( discard_c ), "=d" ( discard_d )
 				       : "a" ( 0xe820 ), "b" ( next ),
-					 "D" ( &__from_data16 ( e820buf ) ),
+					 "D" ( __from_data16 ( &e820buf ) ),
 					 "c" ( sizeof ( e820buf ) ),
 					 "d" ( SMAP )
 				       : "memory" );
diff --git a/src/arch/i386/include/libkir.h b/src/arch/i386/include/libkir.h
index 5f67a56d8..1f5b13504 100644
--- a/src/arch/i386/include/libkir.h
+++ b/src/arch/i386/include/libkir.h
@@ -19,8 +19,8 @@
 #define __text16_array( variable,array ) variable array
 #define __use_data16( variable ) variable
 #define __use_text16( variable ) variable
-#define __from_data16( variable ) variable
-#define __from_text16( variable ) variable
+#define __from_data16( pointer ) pointer
+#define __from_text16( pointer ) pointer
 
 /* Real-mode data and code segments */
 static inline __attribute__ (( always_inline )) unsigned int _rm_cs ( void ) {
diff --git a/src/arch/i386/include/librm.h b/src/arch/i386/include/librm.h
index 31b509793..413f0362e 100644
--- a/src/arch/i386/include/librm.h
+++ b/src/arch/i386/include/librm.h
@@ -51,13 +51,13 @@ extern char *text16;
 	( * ( ( typeof ( _text16_ ## variable ) * )			\
 	      & ( text16 [ ( size_t ) & ( _text16_ ## variable ) ] ) ) )
 
-#define __from_data16( variable )					\
-	( * ( ( typeof ( variable ) * )					\
-	      ( ( ( void * ) &(variable) ) - ( ( void * ) data16 ) ) ) )
+#define __from_data16( pointer )					\
+	( ( unsigned int )						\
+	  ( ( ( void * ) (pointer) ) - ( ( void * ) data16 ) ) )
 
-#define __from_text16( variable )					\
-	( * ( ( typeof ( variable ) * )					\
-	      ( ( ( void * ) &(variable) ) - ( ( void * ) text16 ) ) ) )
+#define __from_text16( pointer )					\
+	( ( unsigned int )						\
+	  ( ( ( void * ) (pointer) ) - ( ( void * ) text16 ) ) )
 
 /* Variables in librm.S, present in the normal data segment */
 extern uint16_t __data16 ( rm_cs );
diff --git a/src/arch/i386/interface/pxe/pxe_call.c b/src/arch/i386/interface/pxe/pxe_call.c
index 5b307d409..3a5f4c751 100644
--- a/src/arch/i386/interface/pxe/pxe_call.c
+++ b/src/arch/i386/interface/pxe/pxe_call.c
@@ -441,8 +441,8 @@ int pxe_start_nbp ( void ) {
 					   "addw $4, %%sp\n\t" )
 			       : "=a" ( rc ), "=b" ( discard_b ),
 			         "=c" ( discard_c )
-			       :  "a" ( & __from_text16 ( ppxe ) ),
-			          "b" ( & __from_text16 ( pxenv ) ),
+			       :  "a" ( __from_text16 ( &ppxe ) ),
+			          "b" ( __from_text16 ( &pxenv ) ),
 			          "c" ( rm_cs )
 			       : "edx", "esi", "edi", "ebp", "memory" );