[librm] Provide an abstraction wrapper for prot_call

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

src/arch/i386/include/bits/compiler.h

 #ifndef ASSEMBLY
 
 /** Declare a function with standard calling conventions */
-#define __asmcall __attribute__ (( cdecl, regparm(0) ))
+#define __asmcall __attribute__ (( used, cdecl, regparm(0) ))
 
 /**
  * Declare a function with libgcc implicit linkage

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

 
 	__asm__ __volatile__ (
 		TEXT16_CODE ( "\nint20_wrapper:\n\t"
-		              "pushl %0\n\t"
-		              "call prot_call\n\t"
+			      VIRT_CALL ( int20 )
 			      "clc\n\t"
 			      "call patch_cf\n\t"
-		              "iret\n\t" )
-		          : : "i" ( int20 ) );
+		              "iret\n\t" ) );
 
 	hook_bios_interrupt ( 0x20, ( intptr_t ) int20_wrapper, &int20_vector );
 
 	__asm__ __volatile__ (
 		TEXT16_CODE ( "\nint21_wrapper:\n\t"
-		              "pushl %0\n\t"
-		              "call prot_call\n\t"
+			      VIRT_CALL ( int21 )
 			      "clc\n\t"
 			      "call patch_cf\n\t"
-		              "iret\n\t" )
-		          : : "i" ( int21 ) );
+		              "iret\n\t" ) );
 
 	hook_bios_interrupt ( 0x21, ( intptr_t ) int21_wrapper, &int21_vector );
 
 	__asm__  __volatile__ (
 		TEXT16_CODE ( "\nint22_wrapper:\n\t"
-		              "pushl %0\n\t"
-		              "call prot_call\n\t"
+			      VIRT_CALL ( int22 )
 			      "clc\n\t"
 			      "call patch_cf\n\t"
-		              "iret\n\t" )
-		          : : "i" ( int22) );
+		              "iret\n\t" ) );
 
 	hook_bios_interrupt ( 0x22, ( intptr_t ) int22_wrapper, &int22_vector );
 }

src/arch/x86/core/dumpregs.c

 	__asm__ __volatile__ (
 		TEXT16_CODE ( ".globl dump_regs\n\t"
 			      "\ndump_regs:\n\t"
-			      "pushl $_dump_regs\n\t"
-			      "call prot_call\n\t"
-			      "ret\n\t" ) : : );
+			      VIRT_CALL ( _dump_regs )
+			      "ret\n\t" ) );
 
 	printf ( "EAX=%08x EBX=%08x ECX=%08x EDX=%08x\n"
 		 "ESI=%08x EDI=%08x EBP=%08x ESP=%08x\n"

src/arch/x86/include/librm.h

 #define LONG_DS 0x40
 #endif
 
-#ifndef ASSEMBLY
+#ifdef ASSEMBLY
+
+/**
+ * Call C function from real-mode code
+ *
+ * @v function		C function
+ */
+.macro virtcall function
+	pushl	$\function
+	call	prot_call
+.endm
+
+#else /* ASSEMBLY */
 
 #ifdef UACCESS_LIBRM
 #define UACCESS_PREFIX_librm
 #define UACCESS_PREFIX_librm __librm_
 #endif
 
+/**
+ * Call C function from real-mode code
+ *
+ * @v function		C function
+ */
+#define VIRT_CALL( function )						\
+	"pushl $( " #function " )\n\t"					\
+	"call prot_call\n\t"
+
 /* Variables in librm.S */
 extern unsigned long virt_offset;
 

src/arch/x86/interface/pcbios/bios_console.c

 	__asm__ __volatile__ (
 		TEXT16_CODE ( "\nint16_wrapper:\n\t"
 			      "pushfw\n\t"
-			      "cmpb $0, %%cs:bios_inject_lock\n\t"
+			      "cmpb $0, %cs:bios_inject_lock\n\t"
 			      "jnz 1f\n\t"
-			      "pushl %0\n\t"
-			      "call prot_call\n\t"
+			      VIRT_CALL ( bios_inject )
 			      "\n1:\n\t"
 			      "popfw\n\t"
-			      "ljmp *%%cs:int16_vector\n\t" )
-		: : "i" ( bios_inject ) );
+			      "ljmp *%cs:int16_vector\n\t" ) );
 
 	/* Hook INT 16 */
 	hook_bios_interrupt ( 0x16, ( ( intptr_t ) int16_wrapper ),

src/arch/x86/interface/pcbios/bios_reboot.c

 	put_real ( flag, BDA_SEG, BDA_REBOOT );
 
 	/* Jump to system reset vector */
-	__asm__ __volatile__ ( REAL_CODE ( "ljmp $0xf000, $0xfff0" ) : : );
+	__asm__ __volatile__ ( REAL_CODE ( "ljmp $0xf000, $0xfff0" ) );
 }
 
 PROVIDE_REBOOT ( pcbios, reboot, bios_reboot );

src/arch/x86/interface/pcbios/int13.c

 			     /* Clear OF, set CF, call int13() */
 			     "orb $0, %%al\n\t" 
 			     "stc\n\t"
-			     "pushl %0\n\t"
-			     "call prot_call\n\t"
+			     VIRT_CALL ( int13 )
 			     /* Chain if OF not set */
 			     "jo 1f\n\t"
 			     "pushfw\n\t"
 			     "\n3:\n\t"
 			     "movw %%bp, %%sp\n\t"
 			     "popw %%bp\n\t"
-			     "iret\n\t" )
-	       : : "i" ( int13 ) );
+			     "iret\n\t" ) : : );
 
 	hook_bios_interrupt ( 0x13, ( intptr_t ) int13_wrapper, &int13_vector );
 }

src/arch/x86/interface/pxe/pxe_entry.S

 
 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
 
+#include <librm.h>
+
 	.arch i386
 
 /****************************************************************************
 	.section ".text16", "ax", @progbits
 	.code16
 pxenv_entry:
-	pushl	$pxe_api_call
-	call	prot_call
+	virtcall pxe_api_call
 	lret
 	.size	pxenv_entry, . - pxenv_entry
 

src/arch/x86/prefix/dskprefix.S

 
 FILE_LICENCE ( GPL2_ONLY )
 
+#include <librm.h>
+
 .equ	BOOTSEG, 0x07C0			/* original address of boot-sector */
 
 .equ	SYSSEG, 0x1000			/* system loaded at SYSSEG<<4 */
 	lret
 	.section ".text16", "awx", @progbits
 1:
-	pushl	$main
-	call	prot_call
+	/* Run iPXE */
+	virtcall main
 
 	/* Uninstall iPXE */
 	call	uninstall

src/arch/x86/prefix/exeprefix.S

 
 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
 
+#include <librm.h>
+
 /* Initial temporary stack size */
 #define EXE_STACK_SIZE 0x400
 
 	movl	%esi, cmdline_phys
 
 	/* Run iPXE */
-	pushl	$main
-	call	prot_call
+	virtcall main
 
 	/* Uninstall iPXE */
 	call	uninstall

src/arch/x86/prefix/hdprefix.S

 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
 
+#include <librm.h>
+
 	.text
 	.arch i386
 	.section ".prefix", "awx", @progbits
 	lret
 	.section ".text16", "awx", @progbits
 1:
-	pushl	$main
-	call	prot_call
+	/* Run iPXE */
+	virtcall main
 
 	/* Uninstall iPXE */
 	call	uninstall

src/arch/x86/prefix/libprefix.S

 
 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
 
+#include <librm.h>
+
 	.arch i386
 
 /* Image compression enabled */
 	 * ready for the copy to the new location.
 	 */
 	progress "  relocate\n"
-	pushl	$relocate
-	call	prot_call
+	virtcall relocate
 
 	/* Jump back to .prefix segment */
 	pushw	$1f

src/arch/x86/prefix/lkrnprefix.S

 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
 
+#include <librm.h>
+
 #define BZI_LOAD_HIGH_ADDR 0x100000
 
 	.text
 	movl	%ecx, initrd_len
 
 	/* Run iPXE */
-	pushl	$main
-	call	prot_call
+	virtcall main
 
 	/* Uninstall iPXE */
 	call	uninstall

src/arch/x86/prefix/nbiprefix.S

 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
 
+#include <librm.h>
+
 	.text
 	.arch i386
 	.code16
 	lret
 	.section ".text16", "awx", @progbits
 1:
-	pushl	$main
-	call	prot_call
+	/* Run iPXE */
+	virtcall main
 
 	/* Uninstall iPXE */
 	call	uninstall

src/arch/x86/prefix/pxeprefix.S

 	.org 0
 	.code16
 
+#include <librm.h>
 #include <undi.h>
 
 #define STACK_MAGIC ( 'L' + ( 'R' << 8 ) + ( 'E' << 16 ) + ( 'T' << 24 ) )
 	movl	%ecx, cached_dhcpack_phys
 
 	/* Run main program */
-	pushl	$main
-	call	prot_call
+	virtcall main
 
 	/* Uninstall iPXE */
 	call	uninstall

src/arch/x86/prefix/romprefix.S

 
 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
 
+#include <librm.h>
 #include <config/general.h>
 #include <config/branding.h>
 
 #endif /* AUTOBOOT_ROM_FILTER */
 .endif
 
-	/* Call main() */
-	pushl	$main
-	call	prot_call
+	/* Run iPXE */
+	virtcall main
 
 	/* Set up flat real mode for return to BIOS */
 	call	flatten_real_mode

src/arch/x86/prefix/undiloader.S

 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
 
+#include <librm.h>
+
 	.text
 	.code16
 	.arch i386
 	.section ".text16", "ax", @progbits
 1:
 	/* Call UNDI loader C code */
-	pushl	$pxe_loader_call
-	call	prot_call
+	virtcall pxe_loader_call
 
 1:	/* Restore registers and return */
 	popw	%bx

src/arch/x86/transitions/librm.S

 	addl	$gdt, gdt_base
 
 	/* Initialise IDT */
-	pushl	$init_idt
-	call	prot_call
+	virtcall init_idt
 
 	/* Restore registers */
 	negl	%edi
 	movb	$0x8f, real_cs + 6
 	movb	$0x8f, real_ds + 6
 	/* Call dummy protected-mode function */
-	pushl	$flatten_dummy
-	call	prot_call
+	virtcall flatten_dummy
 	/* Restore GDT */
 	movb	$0x00, real_cs + 6
 	movb	$0x00, real_ds + 6

src/arch/x86/transitions/librm_test.c

 static struct profiler prot_call_profiler __profiler = { .name = "prot_call" };
 
 /**
- * Dummy protected-mode function
+ * Dummy function for profiling tests
  */
-static void librm_test_prot_call ( void ) {
+static __asmcall void librm_test_call ( struct i386_all_regs *ix86 __unused ) {
 	/* Do nothing */
 }
 
 	/* Profile complete real-mode call cycle */
 	for ( i = 0 ; i < PROFILE_COUNT ; i++ ) {
 		profile_start ( &real_call_profiler );
-		__asm__ __volatile__ ( REAL_CODE ( "" ) : : );
+		__asm__ __volatile__ ( REAL_CODE ( "" ) );
 		profile_stop ( &real_call_profiler );
 	}
 
 	for ( i = 0 ; i < PROFILE_COUNT ; i++ ) {
 		__asm__ __volatile__ ( REAL_CODE ( "rdtsc\n\t"
 						   "movl %k0, %k2\n\t"
-						   "pushl %k3\n\t"
-						   "call prot_call\n\t"
+						   VIRT_CALL ( librm_test_call )
 						   "rdtsc\n\t" )
 				       : "=a" ( stopped ), "=d" ( discard_d ),
-					 "=R" ( started )
-				       : "i" ( librm_test_prot_call ) );
+					 "=R" ( started ) : );
 		profile_start_at ( &prot_call_profiler, started );
 		profile_stop_at ( &prot_call_profiler, stopped );
 	}

src/arch/x86_64/include/bits/compiler.h

 #ifndef ASSEMBLY
 
 /** Declare a function with standard calling conventions */
-#define __asmcall __attribute__ (( regparm(0) ))
+#define __asmcall __attribute__ (( used, regparm(0) ))
 
 /** Declare a function with libgcc implicit linkage */
 #define __libgcc