Allowed zero-cost enforced ordering of features in startup banner

list.

Added FEATURE() macros to most relevant (non-driver) files.

src/arch/i386/image/bzimage.c

 #include <gpxe/init.h>
 #include <gpxe/initrd.h>
 #include <gpxe/cpio.h>
+#include <gpxe/features.h>
+
+FEATURE ( FEATURE_IMAGE, "bzImage", DHCP_EB_FEATURE_BZIMAGE, 1 );
 
 struct image_type bzimage_image_type __image_type ( PROBE_NORMAL );
 

src/arch/i386/image/multiboot.c

 #include <gpxe/memmap.h>
 #include <gpxe/elf.h>
 #include <gpxe/init.h>
+#include <gpxe/features.h>
+
+FEATURE ( FEATURE_IMAGE, "Multiboot", DHCP_EB_FEATURE_MULTIBOOT, 1 );
 
 struct image_type multiboot_image_type __image_type ( PROBE_MULTIBOOT );
 

src/arch/i386/image/nbi.c

 #include <gpxe/netdevice.h>
 #include <gpxe/dhcp.h>
 #include <gpxe/image.h>
+#include <gpxe/features.h>
 
 /** @file
  *
  *
  */
 
+FEATURE ( FEATURE_IMAGE, "NBI", DHCP_EB_FEATURE_NBI, 1 );
+
 struct image_type nbi_image_type __image_type ( PROBE_NORMAL );
 
 /**

src/arch/i386/image/pxe_image.c

 #include <gpxe/image.h>
 #include <gpxe/segment.h>
 #include <gpxe/netdevice.h>
+#include <gpxe/features.h>
+
+FEATURE ( FEATURE_IMAGE, "PXE", DHCP_EB_FEATURE_PXE, 1 );
 
 struct image_type pxe_image_type __image_type ( PROBE_PXE );
 

src/hci/shell_banner.c

 #define BOLD	"\033[1m"
 #define CYAN	"\033[36m"
 
-static char * features[0] __table_start ( char *, features );
-static char * features_end[0] __table_end ( char *, features );
+static struct feature features[0] __table_start ( struct feature, features );
+static struct feature features_end[0] __table_end ( struct feature, features );
 
 /**
  * Print shell banner and prompt for shell entry
  */
 int shell_banner ( void ) {
 	unsigned long timeout = ( currticks() + BANNER_TIMEOUT );
-	char **feature;
+	struct feature *feature;
 	int key;
 	int enter_shell = 0;
 
 		 CYAN "http://etherboot.org" NORMAL "\n"
 		 "Features:" );
 	for ( feature = features ; feature < features_end ; feature++ ) {
-		printf ( " %s", *feature );
+		printf ( " %s", feature->name );
 	}
 	printf ( "\nPress Ctrl-B for the gPXE command line..." );
 

src/include/gpxe/features.h

  *
  */
 
+/**
+ * @defgroup featurecat Feature categories
+ * @{
+ */
+
+#define FEATURE_PROTOCOL		01 /**< Network protocols */
+#define FEATURE_IMAGE			02 /**< Image formats */
+#define FEATURE_MISC			03 /**< Miscellaneous */
+
+/** @} */
+
 /**
  * @defgroup dhcpfeatures DHCP feature option tags
  *
  * @{
  */
 
-/** PXE API extensions */
-#define DHCP_EB_FEATURE_PXE_EXT 0x10
-
-/** iSCSI */
-#define DHCP_EB_FEATURE_ISCSI 0x11
-
-/** AoE */
-#define DHCP_EB_FEATURE_AOE 0x12
-
-/** HTTP */
-#define DHCP_EB_FEATURE_HTTP 0x13
-
-/** HTTPS */
-#define DHCP_EB_FEATURE_HTTPS 0x14
+#define DHCP_EB_FEATURE_PXE_EXT		0x10 /**< PXE API extensions */
+#define DHCP_EB_FEATURE_ISCSI		0x11 /**< iSCSI protocol */
+#define DHCP_EB_FEATURE_AOE		0x12 /**< AoE protocol */
+#define DHCP_EB_FEATURE_HTTP		0x13 /**< HTTP protocol */
+#define DHCP_EB_FEATURE_HTTPS		0x14 /**< HTTPS protocol */
+#define DHCP_EB_FEATURE_TFTP		0x15 /**< TFTP protocol */
+#define DHCP_EB_FEATURE_FTP		0x16 /**< FTP protocol */
+#define DHCP_EB_FEATURE_DNS		0x17 /**< DNS protocol */
+#define DHCP_EB_FEATURE_BZIMAGE		0x18 /**< bzImage format */
+#define DHCP_EB_FEATURE_MULTIBOOT	0x19 /**< Multiboot format */
+#define DHCP_EB_FEATURE_NBI		0x20 /**< NBI format */
+#define DHCP_EB_FEATURE_PXE		0x21 /**< PXE format */
 
 /** @} */
 
 /** Declare a feature code for DHCP */
-#define __dhcp_feature __table ( uint8_t, dhcp_features, 01 )
+#define __dhcp_feature( category )					    \
+	 __table ( uint8_t, dhcp_features, category )
 
 /** Construct a DHCP feature table entry */
-#define DHCP_FEATURE( feature_opt, version ) \
-	_DHCP_FEATURE ( OBJECT, feature_opt, version )
-#define _DHCP_FEATURE( _name, feature_opt, version ) \
-	__DHCP_FEATURE ( _name, feature_opt, version )
-#define __DHCP_FEATURE( _name, feature_opt, version )		\
-	uint8_t __dhcp_feature_ ## _name [] __dhcp_feature = {	\
-		feature_opt, DHCP_BYTE ( version )		\
+#define DHCP_FEATURE( category, feature_opt, version )			    \
+	_DHCP_FEATURE ( category, OBJECT, feature_opt, version )
+#define _DHCP_FEATURE( category, _name, feature_opt, version )		    \
+	__DHCP_FEATURE ( category, _name, feature_opt, version )
+#define __DHCP_FEATURE( category, _name, feature_opt, version )		    \
+	uint8_t __dhcp_feature_ ## _name [] __dhcp_feature ( category ) = { \
+		feature_opt, DHCP_BYTE ( version )			    \
 	};
 
+/** A named feature */
+struct feature {
+	/** Feature name */
+	char *name;
+};
+
 /** Declare a named feature */
-#define __feature_name __table ( char *, features, 01 )
+#define __feature_name( category )					    \
+	__table ( struct feature, features, category )
 
 /** Construct a named feature */
-#define FEATURE_NAME( text ) \
-	_FEATURE_NAME ( OBJECT, text )
-#define _FEATURE_NAME( _name, text ) \
-	__FEATURE_NAME ( _name, text )
-#define __FEATURE_NAME( _name, text )				\
-	char * __feature_ ## _name __feature_name = text;
+#define FEATURE_NAME( category, text )					    \
+	_FEATURE_NAME ( category, OBJECT, text )
+#define _FEATURE_NAME( category, _name, text )				    \
+	__FEATURE_NAME ( category, _name, text )
+#define __FEATURE_NAME( category, _name, text )				    \
+	struct feature __feature_ ## _name __feature_name ( category ) = {  \
+		.name = text,						    \
+	};
 
 /** Declare a feature */
-#define FEATURE( text, feature_opt, version )			\
-	FEATURE_NAME ( text );					\
-	DHCP_FEATURE ( feature_opt, version );
+#define FEATURE( category, text, feature_opt, version )			    \
+	FEATURE_NAME ( category, text );				    \
+	DHCP_FEATURE ( category, feature_opt, version );
 
 #endif /* _GPXE_FEATURES_H */

src/net/aoe.c

  *
  */
 
-FEATURE ( "AoE", DHCP_EB_FEATURE_AOE, 1 );
+FEATURE ( FEATURE_PROTOCOL, "AoE", DHCP_EB_FEATURE_AOE, 1 );
 
 struct net_protocol aoe_protocol;
 

src/net/tcp/ftp.c

 #include <gpxe/xfer.h>
 #include <gpxe/open.h>
 #include <gpxe/uri.h>
+#include <gpxe/features.h>
 #include <gpxe/ftp.h>
 
 /** @file
  *
  */
 
+FEATURE ( FEATURE_PROTOCOL, "FTP", DHCP_EB_FEATURE_FTP, 1 );
+
 /**
  * FTP states
  *

src/net/tcp/http.c

 #include <gpxe/features.h>
 #include <gpxe/http.h>
 
-FEATURE ( "HTTP", DHCP_EB_FEATURE_HTTP, 1 );
+FEATURE ( FEATURE_PROTOCOL, "HTTP", DHCP_EB_FEATURE_HTTP, 1 );
 
 /** HTTP receive state */
 enum http_rx_state {

src/net/tcp/https.c

 #include <gpxe/http.h>
 #include <gpxe/features.h>
 
-FEATURE ( "HTTPS", DHCP_EB_FEATURE_HTTPS, 1 );
+FEATURE ( FEATURE_PROTOCOL, "HTTPS", DHCP_EB_FEATURE_HTTPS, 1 );
 
 /**
  * Initiate an HTTPS connection

src/net/tcp/iscsi.c

  *
  */
 
-FEATURE ( "iSCSI", DHCP_EB_FEATURE_ISCSI, 1 );
+FEATURE ( FEATURE_PROTOCOL, "iSCSI", DHCP_EB_FEATURE_ISCSI, 1 );
 
 /** iSCSI initiator name (explicitly specified) */
 static char *iscsi_explicit_initiator_iqn;

src/net/udp/dns.c

 #include <gpxe/retry.h>
 #include <gpxe/tcpip.h>
 #include <gpxe/dhcp.h>
+#include <gpxe/features.h>
 #include <gpxe/dns.h>
 
 /** @file
  *
  */
 
+FEATURE ( FEATURE_PROTOCOL, "DNS", DHCP_EB_FEATURE_DNS, 1 );
+
 /** The DNS server */
 static struct sockaddr_tcpip nameserver = {
 	.st_port = htons ( DNS_PORT ),

src/net/udp/tftp.c

 #include <gpxe/uri.h>
 #include <gpxe/tcpip.h>
 #include <gpxe/retry.h>
+#include <gpxe/features.h>
 #include <gpxe/tftp.h>
 
 /** @file
  *
  */
 
+FEATURE ( FEATURE_PROTOCOL, "TFTP", DHCP_EB_FEATURE_TFTP, 1 );
+
 /**
  * A TFTP request
  *