Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

===================================================================
RCS file: /ftp/cvs/cvsroot/src/sys/arch/i386/i386/locore.S,v
rcsdiff: /ftp/cvs/cvsroot/src/sys/arch/i386/i386/locore.S,v: warning: Unknown phrases like `commitid ...;' are present.
retrieving revision 1.95.4.4
retrieving revision 1.96
diff -u -p -r1.95.4.4 -r1.96
--- src/sys/arch/i386/i386/locore.S	2014/05/22 11:39:51	1.95.4.4
+++ src/sys/arch/i386/i386/locore.S	2012/02/24 08:06:07	1.96
@@ -1,4 +1,4 @@
-/*	$NetBSD: locore.S,v 1.95.4.4 2014/05/22 11:39:51 yamt Exp $	*/
+/*	$NetBSD: locore.S,v 1.96 2012/02/24 08:06:07 cherry Exp $	*/
 
 /*
  * Copyright-o-rama!
@@ -129,7 +129,7 @@
  */
 
 #include <machine/asm.h>
-__KERNEL_RCSID(0, "$NetBSD: locore.S,v 1.95.4.4 2014/05/22 11:39:51 yamt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: locore.S,v 1.96 2012/02/24 08:06:07 cherry Exp $");
 
 #include "opt_compat_oldboot.h"
 #include "opt_ddb.h"
@@ -139,6 +139,7 @@ __KERNEL_RCSID(0, "$NetBSD: locore.S,v 1
 #include "opt_vm86.h"
 #include "opt_xen.h"
 
+#include "npx.h"
 #include "assym.h"
 #include "lapic.h"
 #include "ioapic.h"
@@ -162,46 +163,45 @@ __KERNEL_RCSID(0, "$NetBSD: locore.S,v 1
 /* Get definitions for IOM_BEGIN, IOM_END, and IOM_SIZE */
 #include <dev/isa/isareg.h>
 
-#ifndef XEN
-#define	_RELOC(x)	((x) - KERNBASE)
-#else
-#define	_RELOC(x)	((x))
-#endif /* XEN */
-#define	RELOC(x)	_RELOC(_C_LABEL(x))
-
 #ifdef XEN
 /*
  * Xen guest identifier and loader selection
  */
 .section __xen_guest
 	.ascii	"GUEST_OS=netbsd,GUEST_VER=3.0,XEN_VER=xen-3.0"
-	.ascii	",VIRT_BASE=0xc0000000" /* KERNBASE */
-	.ascii	",ELF_PADDR_OFFSET=0xc0000000" /* KERNBASE */
-	.ascii	",VIRT_ENTRY=0xc0100000" /* KERNTEXTOFF */
-	.ascii	",HYPERCALL_PAGE=0x00000101"
+#if defined(DOM0OPS) || !defined(XEN_COMPAT_030001)
+	.ascii  ",VIRT_BASE=0xc0000000" /* KERNBASE */
+	.ascii  ",ELF_PADDR_OFFSET=0xc0000000" /* KERNBASE */
+#else
+	.ascii  ",VIRT_BASE=0xc0100000" /* KERNTEXTOFF */
+	.ascii  ",ELF_PADDR_OFFSET=0xc0100000" /* KERNTEXTOFF */
+#endif
+	.ascii  ",VIRT_ENTRY=0xc0100000" /* KERNTEXTOFF */
+#if !defined(XEN_COMPAT_030001)
+	.ascii  ",HYPERCALL_PAGE=0x00000101"
 		/* (???+HYPERCALL_PAGE_OFFSET)/PAGE_SIZE) */
+#endif
 #ifdef PAE
-	.ascii	",PAE=yes[extended-cr3]"
+	.ascii  ",PAE=yes[extended-cr3]"
 #endif
 	.ascii	",LOADER=generic"
 #if (NKSYMS || defined(DDB) || defined(MODULAR)) && !defined(SYMTAB_SPACE)
 	.ascii	",BSD_SYMTAB=yes"
 #endif
 	.byte	0
-#endif	/* XEN */
+#endif
 
 /*
  * Initialization
  */
 	.data
 
-	.globl	_C_LABEL(cputype)
+	.globl	_C_LABEL(cpu)
 	.globl	_C_LABEL(cpuid_level)
 	.globl	_C_LABEL(esym)
 	.globl	_C_LABEL(eblob)
 	.globl	_C_LABEL(atdevbase)
-	.globl	_C_LABEL(lwp0uarea)
-	.globl	_C_LABEL(PDPpaddr)
+	.globl	_C_LABEL(lwp0uarea),_C_LABEL(PDPpaddr)
 	.globl	_C_LABEL(gdt)
 	.globl	_C_LABEL(idt)
 	.globl	_C_LABEL(lapic_tpr)
@@ -213,68 +213,52 @@ __KERNEL_RCSID(0, "$NetBSD: locore.S,v 1
 	.align	12
 #endif
 	.globl _C_LABEL(local_apic), _C_LABEL(lapic_id)
-	.type	_C_LABEL(local_apic), @object
-LABEL(local_apic)
+_C_LABEL(local_apic):
 	.space	LAPIC_ID
-END(local_apic)
-	.type	_C_LABEL(lapic_id), @object
-LABEL(lapic_id)
+_C_LABEL(lapic_id):
 	.long	0x00000000
-	.space	LAPIC_TPRI-(LAPIC_ID+4)
-END(lapic_id)
-	.type	_C_LABEL(lapic_tpr), @object
-LABEL(lapic_tpr)
-	.space	LAPIC_PPRI-LAPIC_TPRI
-END(lapic_tpr)
-	.type	_C_LABEL(lapic_ppr), @object
+	.space  LAPIC_TPRI-(LAPIC_ID+4)
+_C_LABEL(lapic_tpr):
+	.space  LAPIC_PPRI-LAPIC_TPRI
 _C_LABEL(lapic_ppr):
 	.space	LAPIC_ISR-LAPIC_PPRI
-END(lapic_ppr)
-	.type	_C_LABEL(lapic_isr), @object
 _C_LABEL(lapic_isr):
 	.space	PAGE_SIZE-LAPIC_ISR
-END(lapic_isr)
 #else
-	.type	_C_LABEL(lapic_tpr), @object
-LABEL(lapic_tpr)
+_C_LABEL(lapic_tpr):
 	.long 0
-END(lapic_tpr)
 #endif
-	.type	_C_LABEL(cputype), @object
-LABEL(cputype)		.long	0	# are we 80486, Pentium, or..
-END(cputype)
-	.type	_C_LABEL(cpuid_level), @object
-LABEL(cpuid_level)	.long	0
-END(cpuid_level)
-	.type	_C_LABEL(atdevbase), @object
-LABEL(atdevbase)	.long	0	# location of start of iomem in virtual
-END(atdevbase)
-	.type	_C_LABEL(lwp0uarea), @object
-LABEL(lwp0uarea)	.long	0
-END(lwp0uarea)
-	.type	_C_LABEL(PDPpaddr), @object
-LABEL(PDPpaddr)		.long	0	# paddr of PDP, for libkvm
-END(PDPpaddr)
-	.type	_C_LABEL(tablesize), @object
+
+_C_LABEL(cpu):		.long	0	# are we 80486, Pentium, or..
+_C_LABEL(cpuid_level):	.long	0
+_C_LABEL(atdevbase):	.long	0	# location of start of iomem in virtual
+_C_LABEL(lwp0uarea):	.long	0
+_C_LABEL(PDPpaddr):	.long	0	# paddr of PDP, for libkvm
 _C_LABEL(tablesize):	.long	0
-END(tablesize)
-	.size	tmpstk, tmpstk - .
+
 	.space 512
 tmpstk:
 #ifdef XEN
 	.align 		PAGE_SIZE, 0x0	# Align on page boundary
-LABEL(tmpgdt)
+_C_LABEL(tmpgdt):
 	.space 		PAGE_SIZE	# Xen expects a page
-END(tmpgdt)
 #endif /* XEN */
+	.globl tmpgdt
+#ifndef XEN
+#define	_RELOC(x)	((x) - KERNBASE)
+#else
+#define	_RELOC(x)	((x))
+#endif /* XEN */
+#define	RELOC(x)	_RELOC(_C_LABEL(x))
 
 	.text
 	.globl	_C_LABEL(kernel_text)
 	.set	_C_LABEL(kernel_text),KERNTEXTOFF
 
-ENTRY(start)
+	.globl	start
 #ifndef XEN
-	movw	$0x1234,0x472			# warm boot
+start:	movw	$0x1234,0x472			# warm boot
+
 #if defined(MULTIBOOT)
 	jmp	1f
 
@@ -362,11 +346,11 @@ isnx586:
 	 * Don't try cpuid, as Nx586s reportedly don't support the
 	 * PSL_ID bit.
 	 */
-	movl	$CPU_NX586,RELOC(cputype)
+	movl	$CPU_NX586,RELOC(cpu)
 	jmp	2f
 
 is386:
-	movl	$CPU_386,RELOC(cputype)
+	movl	$CPU_386,RELOC(cpu)
 	jmp	2f
 
 try486:	/* Try to toggle identification flag; does not exist on early 486s. */
@@ -385,7 +369,7 @@ try486:	/* Try to toggle identification 
 
 	testl	%eax,%eax
 	jnz	try586
-is486:	movl	$CPU_486,RELOC(cputype)
+is486:	movl	$CPU_486,RELOC(cpu)
 	/*
 	 * Check Cyrix CPU
 	 * Cyrix CPUs do not change the undefined flags following
@@ -403,7 +387,7 @@ is486:	movl	$CPU_486,RELOC(cputype)
 	popfl
 	jmp 2f
 trycyrix486:
-	movl	$CPU_6x86,RELOC(cputype)	# set CPU type
+	movl	$CPU_6x86,RELOC(cpu) 	# set CPU type
 	/*
 	 * Check for Cyrix 486 CPU by seeing if the flags change during a
 	 * divide. This is documented in the Cx486SLC/e SMM Programmer's
@@ -421,7 +405,7 @@ trycyrix486:
 	xorl	%ecx,%eax		# are the flags different?
 	testl	$0x8d5,%eax		# only check C|PF|AF|Z|N|V
 	jne	2f			# yes; must be Cyrix 6x86 CPU
-	movl	$CPU_486DLC,RELOC(cputype) 	# set CPU type
+	movl	$CPU_486DLC,RELOC(cpu) 	# set CPU type
 
 #ifndef CYRIX_CACHE_WORKS
 	/* Disable caching of the ISA hole only. */
@@ -528,7 +512,7 @@ try586:	/* Use the `cpuid' instruction. 
  *	eax = pte (page frame | control | status)
  *	ebx = page table address
  *	ecx = number of pages to map
- *
+ * 
  * For PAE, each entry is 8 bytes long: we must set the 4 upper bytes to 0.
  * This is done by the first instruction of fillkpt. In the non-PAE case, this
  * instruction just clears the page table entry.
@@ -536,9 +520,9 @@ try586:	/* Use the `cpuid' instruction. 
 
 #define fillkpt	\
 1:	movl	$0,(PDE_SIZE-4)(%ebx)	;	/* clear bits */	\
-	movl	%eax,(%ebx)		;	/* store phys addr */	\
-	addl	$PDE_SIZE,%ebx		;	/* next pte/pde */	\
-	addl	$PAGE_SIZE,%eax		;	/* next phys page */	\
+	movl	%eax,(%ebx)		;	/* store phys addr */   \
+	addl	$PDE_SIZE,%ebx		;	/* next pte/pde */      \
+	addl	$PAGE_SIZE,%eax		;	/* next phys page */    \
 	loop	1b			;
 
 	/* Find end of kernel image. */
@@ -591,38 +575,38 @@ try586:	/* Use the `cpuid' instruction. 
 	cmpl	%eax,RELOC(nkptp)+1*4
 	jnz	1b
 
-	/* Clear tables */
-	movl	%esi,%edi
+ 	/* Clear tables */
+ 	movl	%esi,%edi
 	xorl	%eax,%eax
 	cld
-	movl	RELOC(tablesize),%ecx
-	shrl	$2,%ecx
+ 	movl	RELOC(tablesize),%ecx
+ 	shrl	$2,%ecx
 	rep
 	stosl
 
-	leal	(PROC0_PTP1_OFF)(%esi), %ebx
+ 	leal	(PROC0_PTP1_OFF)(%esi), %ebx
 
 /*
  * Build initial page tables.
  */
-	/*
-	 * Compute &__data_start - KERNBASE. This can't be > 4G,
+ 	/*
+ 	 * Compute &__data_start - KERNBASE. This can't be > 4G,
 	 * or we can't deal with it anyway, since we can't load it in
 	 * 32 bit mode. So use the bottom 32 bits.
-	 */
-	movl	$RELOC(__data_start),%edx
+ 	 */
+ 	movl	$RELOC(__data_start),%edx
 	andl	$~PGOFSET,%edx
 
-	/*
-	 * Skip the first MB.
-	 */
+ 	/*
+ 	 * Skip the first MB.
+ 	 */
 	movl	$_RELOC(KERNTEXTOFF),%eax
 	movl	%eax,%ecx
 	shrl	$(PGSHIFT-2),%ecx	/* ((n >> PGSHIFT) << 2) for # pdes */
 #ifdef PAE
-	shll	$1,%ecx			/* pdes are twice larger with PAE */
+ 	shll	$1,%ecx			/* pdes are twice larger with PAE */
 #endif
-	addl	%ecx,%ebx
+ 	addl	%ecx,%ebx
 
 	/* Map the kernel text read-only. */
 	movl	%edx,%ecx
@@ -647,24 +631,24 @@ try586:	/* Use the `cpuid' instruction. 
 /*
  * Construct a page table directory.
  */
-	/* Set up top level entries for identity mapping */
-	leal	(PROC0_PDIR_OFF)(%esi),%ebx
-	leal	(PROC0_PTP1_OFF)(%esi),%eax
-	orl	$(PG_V|PG_KW), %eax
-	movl	RELOC(nkptp)+1*4,%ecx
+ 	/* Set up top level entries for identity mapping */
+ 	leal	(PROC0_PDIR_OFF)(%esi),%ebx
+ 	leal	(PROC0_PTP1_OFF)(%esi),%eax
+ 	orl	$(PG_V|PG_KW), %eax
+ 	movl	RELOC(nkptp)+1*4,%ecx
 	fillkpt
 
-	/* Set up top level entries for actual kernel mapping */
-	leal	(PROC0_PDIR_OFF + L2_SLOT_KERNBASE*PDE_SIZE)(%esi),%ebx
-	leal	(PROC0_PTP1_OFF)(%esi),%eax
-	orl	$(PG_V|PG_KW), %eax
-	movl	RELOC(nkptp)+1*4,%ecx
+ 	/* Set up top level entries for actual kernel mapping */
+ 	leal	(PROC0_PDIR_OFF + L2_SLOT_KERNBASE*PDE_SIZE)(%esi),%ebx
+ 	leal	(PROC0_PTP1_OFF)(%esi),%eax
+ 	orl	$(PG_V|PG_KW), %eax
+ 	movl	RELOC(nkptp)+1*4,%ecx
 	fillkpt
 
 	/* Install a PDE recursively mapping page directory as a page table! */
-	leal	(PROC0_PDIR_OFF + PDIR_SLOT_PTE*PDE_SIZE)(%esi),%ebx
-	leal	(PROC0_PDIR_OFF)(%esi),%eax
-	orl	$(PG_V|PG_KW),%eax
+ 	leal	(PROC0_PDIR_OFF + PDIR_SLOT_PTE*PDE_SIZE)(%esi),%ebx
+ 	leal	(PROC0_PDIR_OFF)(%esi),%eax
+ 	orl	$(PG_V|PG_KW),%eax
 	movl	$PDP_SIZE,%ecx
 	fillkpt
 
@@ -693,29 +677,29 @@ try586:	/* Use the `cpuid' instruction. 
 	movl	%esi,%eax		# phys address of ptd in proc 0
 	movl	%eax,%cr3		# load ptd addr into mmu
 
-	/*
-	 * 2. Enable paging and the rest of it.
-	 */
+ 	/*
+ 	 * 2. Enable paging and the rest of it.
+ 	 */
 	movl	%cr0,%eax		# get control word
-					# enable paging & NPX
-	orl	$(CR0_PE|CR0_PG|CR0_NE|CR0_TS|CR0_MP|CR0_WP|CR0_AM),%eax
+					# enable paging & NPX emulation
+	orl	$(CR0_PE|CR0_PG|CR0_NE|CR0_TS|CR0_EM|CR0_MP),%eax
 	movl	%eax,%cr0		# and page NOW!
 
 	pushl	$begin			# jump to high mem
 	ret
 
 begin:
-	/*
-	 * We have arrived.
-	 * There's no need anymore for the identity mapping in low
-	 * memory, remove it.
-	 */
-	movl	_C_LABEL(nkptp)+1*4,%ecx
-	leal	(PROC0_PDIR_OFF)(%esi),%ebx	# old, phys address of PDIR
-	addl	$(KERNBASE), %ebx		# new, virtual address of PDIR
+ 	/*
+ 	 * We have arrived.
+ 	 * There's no need anymore for the identity mapping in low
+ 	 * memory, remove it.
+ 	 */
+ 	movl	_C_LABEL(nkptp)+1*4,%ecx
+ 	leal	(PROC0_PDIR_OFF)(%esi),%ebx	# old, phys address of PDIR
+ 	addl	$(KERNBASE), %ebx		# new, virtual address of PDIR
 1:	movl	$0,(PDE_SIZE-4)(%ebx)		# Upper bits (for PAE)
 	movl	$0,(%ebx)
-	addl	$PDE_SIZE,%ebx
+ 	addl	$PDE_SIZE,%ebx
 	loop	1b
 
 	/* Relocate atdevbase. */
@@ -725,11 +709,11 @@ begin:
 	movl	%edx,_C_LABEL(atdevbase)
 
 	/* Set up bootstrap stack. */
-	leal	(PROC0_STK_OFF+KERNBASE)(%esi),%eax
+ 	leal	(PROC0_STK_OFF+KERNBASE)(%esi),%eax
 	movl	%eax,_C_LABEL(lwp0uarea)
-	leal	(USPACE-FRAMESIZE)(%eax),%esp
-	movl	%esi,PCB_CR3(%eax)	# pcb->pcb_cr3
-	xorl	%ebp,%ebp		# mark end of frames
+	leal	(KSTACK_SIZE-FRAMESIZE)(%eax),%esp
+	movl	%esi,(KSTACK_SIZE+PCB_CR3)(%eax)	# pcb->pcb_cr3
+	xorl	%ebp,%ebp               # mark end of frames
 
 #if defined(MULTIBOOT)
 	/* It is now safe to parse the Multiboot information structure
@@ -744,7 +728,7 @@ begin:
 	call	_C_LABEL(initgdt)
 	addl	$4,%esp
 
-	movl	_C_LABEL(tablesize),%eax
+ 	movl	_C_LABEL(tablesize),%eax
 	addl	%esi,%eax		# skip past stack and page tables
 
 #ifdef PAE
@@ -775,6 +759,7 @@ begin:
 
 	call 	_C_LABEL(main)
 #else /* XEN */
+start:
 	/* First, reset the PSL. */
 	pushl	$PSL_MBO
 	popfl
@@ -783,7 +768,7 @@ begin:
 	movl	%esp, %ebx		# save start of available space
 	movl	$_RELOC(tmpstk),%esp	# bootstrap stack end location
 
-	/* Clear BSS. */
+        /* Clear BSS first so that there are no surprises... */
 	xorl	%eax,%eax
 	movl	$RELOC(__bss_start),%edi
 	movl	$RELOC(_end),%ecx
@@ -791,7 +776,7 @@ begin:
 	rep stosb
 
 	/* Copy the necessary stuff from start_info structure. */
-	/* We need to copy shared_info early, so that sti/cli work */
+        /* We need to copy shared_info early, so that sti/cli work */
 	movl	$RELOC(start_info_union),%edi
 	movl	$128,%ecx
 	rep movsl
@@ -825,8 +810,8 @@ begin:
 	movl	%esi, _C_LABEL(lwp0uarea)
 
 	/* Set up bootstrap stack. */
-	leal	(USPACE-FRAMESIZE)(%eax),%esp
-	xorl	%ebp,%ebp		# mark end of frames
+	leal	(KSTACK_SIZE-FRAMESIZE)(%eax),%esp
+	xorl	%ebp,%ebp               # mark end of frames
 
 	addl	$USPACE, %esi
 	subl	$KERNBASE, %esi		#init386 want a physical address
@@ -838,16 +823,14 @@ begin:
 	call	_C_LABEL(init386)	# wire 386 chip for unix operation
 	addl	$PDE_SIZE,%esp		# pop paddr_t
 	call 	_C_LABEL(main)
-#endif /* XEN */
-END(start)
 
-#if defined(XEN)
+#if defined(XEN) && !defined(XEN_COMPAT_030001)
 /* space for the hypercall call page */
 #define HYPERCALL_PAGE_OFFSET 0x1000
 .org HYPERCALL_PAGE_OFFSET
 ENTRY(hypercall_page)
 .skip 0x1000
-END(hypercall_page)
+#endif /* defined(XEN) && !defined(XEN_COMPAT_030001) */
 
 /*
  * void lgdt_finish(void);
@@ -880,9 +863,8 @@ END(lgdt_finish)
  *
  * This is a trampoline function pushed onto the stack of a newly created
  * process in order to do some additional setup.  The trampoline is entered by
- * cpu_switchto()ing to the process, so we abuse the callee-saved
- * registers used by cpu_switchto() to store the information about the
- * stub to call.
+ * cpu_switch()ing to the process, so we abuse the callee-saved registers used
+ * by cpu_switch() to store the information about the stub to call.
  * NOTE: This function does not have a normal calling sequence!
  */
 NENTRY(lwp_trampoline)
@@ -974,7 +956,7 @@ ENTRY(dumpsys)
 END(dumpsys)
 
 /*
- * struct lwp *cpu_switchto(struct lwp *oldlwp, struct lwp *newlwp,
+ * struct lwp *cpu_switchto(struct lwp *oldlwp, struct *newlwp,
  *			    bool returning)
  *
  *	1. if (oldlwp != NULL), save its context.
@@ -1031,17 +1013,15 @@ ENTRY(cpu_switchto)
 	pushl	%edi
 	call	_C_LABEL(i386_switch_context)
 	addl	$4,%esp
-#else /* !XEN */
+#else /* XEN */
 	/* Switch ring0 esp */
 	movl	PCB_ESP0(%ebx),%eax
 	movl	%eax,CPUVAR(ESP0)
-#endif /* !XEN */
 
 	/* Don't bother with the rest if switching to a system process. */
 	testl	$LW_SYSTEM,L_FLAG(%edi)
 	jnz	4f
 
-#ifndef XEN
 	/* Restore thread-private %fs/%gs descriptors. */
 	movl	CPUVAR(GDT),%ecx
 	movl	PCB_FSD(%ebx), %eax
@@ -1052,7 +1032,7 @@ ENTRY(cpu_switchto)
 	movl	PCB_GSD+4(%ebx), %edx
 	movl	%eax, (GUGS_SEL*8)(%ecx)
 	movl	%edx, (GUGS_SEL*8+4)(%ecx)
-#endif /* !XEN */
+#endif /* XEN */
 
 	/* Switch I/O bitmap */
 	movl	PCB_IOMAP(%ebx),%eax
@@ -1072,11 +1052,7 @@ ENTRY(cpu_switchto)
 	 * is deferred until mi_switch(), when cpu_switchto() returns.
 	 */
 2:
-#ifdef XEN
-	pushl	%edi
-	call	_C_LABEL(i386_tls_switch)
-	addl	$4,%esp
-#else /* !XEN */
+#ifndef XEN
 	movl	$IPL_HIGH,CPUVAR(ILEVEL)
 	movl	PCB_CR0(%ebx),%ecx		/* has CR0_TS clear */
 	movl	%cr0,%edx
@@ -1093,7 +1069,7 @@ ENTRY(cpu_switchto)
 3:	cmpl	%edx,%ecx
 	je	4f
 	movl	%ecx,%cr0
-#endif /* !XEN */
+#endif /* XEN */
 
 	/* Return to the new LWP, returning 'oldlwp' in %eax. */
 4:	movl	%esi,%eax
@@ -1155,7 +1131,7 @@ IDTVEC(osyscall)
 #endif
 	pushfl			# set eflags in trap frame
 	popl	8(%esp)
-	orl	$PSL_I,8(%esp)	# re-enable ints on return to user
+	orl	$PSL_I,(%esp)	# re-enable ints on return to user
 	pushl	$7		# size of instruction for restart
 	jmp	syscall1
 IDTVEC_END(osyscall)
@@ -1210,13 +1186,13 @@ syscall1:
 .Lsyscall_resume:
 	movl	%ebx,%eax	# get cpl
 	movl	CPUVAR(IUNMASK)(,%eax,4),%eax
-	andl	CPUVAR(IPENDING),%eax	# any non-masked bits left?
+	andl	CPUVAR(IPENDING),%eax   # any non-masked bits left?
 	jz	17f
 	bsrl	%eax,%eax
 	btrl	%eax,CPUVAR(IPENDING)
 	movl	CPUVAR(ISOURCES)(,%eax,4),%eax
 	jmp	*IS_RESUME(%eax)
-17:	movl	%ebx, CPUVAR(ILEVEL)	#restore cpl
+17:	movl	%ebx, CPUVAR(ILEVEL)    #restore cpl
 	jmp	.Lsyscall_checkast
 14:
 #endif /* XEN */
@@ -1287,10 +1263,41 @@ IDTVEC(svr4_fasttrap)
 	cli
 	jmp	2b
 
+#if NNPX > 0
+/*
+ * Special interrupt handlers.  Someday intr0-intr15 will be used to count
+ * interrupts.  We'll still need a special exception 16 handler.  The busy
+ * latch stuff in probintr() can be moved to npxprobe().
+ */
+
+/*
+ * void probeintr(void)
+ */
+NENTRY(probeintr)
+	ss
+	incl	_C_LABEL(npx_intrs_while_probing)
+	pushl	%eax
+	movb	$0x20,%al	# EOI (asm in strings loses cpp features)
+	outb	%al,$0xa0	# IO_ICU2
+	outb	%al,$0x20	# IO_ICU1
+	movb	$0,%al
+	outb	%al,$0xf0	# clear BUSY# latch
+	popl	%eax
+	iret
+END(probeintr)
+
+/*
+ * void probetrap(void)
+ */
+NENTRY(probetrap)
+	ss
+	incl	_C_LABEL(npx_traps_while_probing)
+	fnclex
+	iret
+END(probetrap)
+
 /*
  * int npx586bug1(int a, int b)
- * Used when checking for the FDIV bug on first generations pentiums.
- * Anything 120MHz or above is fine.
  */
 NENTRY(npx586bug1)
 	fildl	4(%esp)		# x
@@ -1304,6 +1311,7 @@ NENTRY(npx586bug1)
 	popl	%eax
 	ret
 END(npx586bug1)
+#endif /* NNPX > 0 */
 
 /*
  * void sse2_idlezero_page(void *pg)