[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.)

9 files changed, 23 insertions, 30 deletions

diff --git a/src/arch/i386/drivers/net/undiload.c b/src/arch/i386/drivers/net/undiload.c
index a3284f80..dbd9e7c2 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 09c29aba..12b954c0 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 b6a8ca3c..97d4861d 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 5f67a56d..1f5b1350 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 31b50979..413f0362 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 5b307d40..3a5f4c75 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" );
 
diff --git a/src/interface/pxe/pxe_loader.c b/src/interface/pxe/pxe_loader.c
index 708d203a..f815bc25 100644
--- a/src/interface/pxe/pxe_loader.c
+++ b/src/interface/pxe/pxe_loader.c
@@ -42,11 +42,9 @@ PXENV_EXIT_t undi_loader ( struct s_UNDI_LOADER *undi_loader ) {
 
 	/* Fill in UNDI loader structure */
 	undi_loader->PXEptr.segment = rm_cs;
-	undi_loader->PXEptr.offset =
-		( ( unsigned ) & __from_text16 ( ppxe ) );
+	undi_loader->PXEptr.offset = __from_text16 ( &ppxe );
 	undi_loader->PXENVptr.segment = rm_cs;
-	undi_loader->PXENVptr.offset =
-		( ( unsigned ) & __from_text16 ( pxenv ) );
+	undi_loader->PXENVptr.offset = __from_text16 ( &pxenv );
 
 	undi_loader->Status = PXENV_STATUS_SUCCESS;
 	return PXENV_EXIT_SUCCESS;
diff --git a/src/interface/pxe/pxe_preboot.c b/src/interface/pxe/pxe_preboot.c
index 3574c7e3..b2914d36 100644
--- a/src/interface/pxe/pxe_preboot.c
+++ b/src/interface/pxe/pxe_preboot.c
@@ -196,8 +196,7 @@ PXENV_EXIT_t pxenv_get_cached_info ( struct s_PXENV_GET_CACHED_INFO
 		 * fill it in.
 		 */
 		get_cached_info->Buffer.segment = rm_ds;
-		get_cached_info->Buffer.offset =
-			( unsigned ) ( & __from_data16 ( *info ) );
+		get_cached_info->Buffer.offset = __from_data16 ( info );
 		get_cached_info->BufferSize = sizeof ( *info );
 		DBG ( " returning %04x:%04x+%04x['%x']",
 		      get_cached_info->Buffer.segment,
diff --git a/src/interface/pxe/pxe_undi.c b/src/interface/pxe/pxe_undi.c
index 76b55df9..26d1c7f5 100644
--- a/src/interface/pxe/pxe_undi.c
+++ b/src/interface/pxe/pxe_undi.c
@@ -597,8 +597,7 @@ PXENV_EXIT_t pxenv_undi_isr ( struct s_PXENV_UNDI_ISR *undi_isr ) {
 		undi_isr->FrameHeaderLength =
 			pxe_netdev->ll_protocol->ll_header_len;
 		undi_isr->Frame.segment = rm_ds;
-		undi_isr->Frame.offset =
-			( ( unsigned ) & __from_data16 ( basemem_packet ) );
+		undi_isr->Frame.offset = __from_data16 ( basemem_packet );
 		/* Probably ought to fill in packet type */
 		undi_isr->ProtType = P_UNKNOWN;
 		undi_isr->PktType = XMT_DESTADDR;