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 1.51.2.1
retrieving revision 1.58
diff -u -p -r1.51.2.1 -r1.58
--- src/sys/arch/i386/i386/locore.S	2007/10/25 22:35:50	1.51.2.1
+++ src/sys/arch/i386/i386/locore.S	2007/12/03 19:06:36	1.58
@@ -1,4 +1,4 @@
-/*	$NetBSD: locore.S,v 1.51.2.1 2007/10/25 22:35:50 bouyer Exp $	*/
+/*	$NetBSD: locore.S,v 1.58 2007/12/03 19:06:36 ad Exp $	*/
 
 /*
  * Copyright-o-rama!
@@ -111,7 +111,6 @@
  */
 
 #include "opt_compat_oldboot.h"
-#include "opt_cputype.h"
 #include "opt_ddb.h"
 #include "opt_realmem.h"
 #include "opt_vm86.h"
@@ -723,7 +722,8 @@ ENTRY(longjmp)
 	ret
 
 /*
- * struct lwp *cpu_switchto(struct lwp *oldlwp, struct newlwp)
+ * struct lwp *cpu_switchto(struct lwp *oldlwp, struct newlwp,
+ *			    bool returning)
  *
  *	1. if (oldlwp != NULL), save its context.
  *	2. then, restore context of newlwp.
@@ -739,6 +739,7 @@ ENTRY(cpu_switchto)
 
 	movl	16(%esp),%esi		# oldlwp
 	movl	20(%esp),%edi		# newlwp
+	movl	24(%esp),%edx		# returning
 	testl	%esi,%esi
 	jz	1f
 
@@ -752,21 +753,35 @@ ENTRY(cpu_switchto)
 	movl	PCB_EBP(%ebx),%ebp
 	movl	PCB_ESP(%ebx),%esp
 
+	/* Set curlwp. */
+	movl	%edi,CPUVAR(CURLWP)
+
+	/* Skip the rest if returning to a pinned LWP. */
+	testl	%edx,%edx
+	jnz	4f
+
 	/* Switch TSS.  Reset "task busy" flag before loading. */
 	movl	%cr3,%eax
 	movl	%eax,PCB_CR3(%ebx)	# for TSS gates
-	movl	CPUVAR(GDT),%eax
+	movl	CPUVAR(GDT),%ecx
 	movl	L_MD_TSS_SEL(%edi),%edx
-	andl	$~0x0200,4(%eax,%edx, 1)
+	andl	$~0x0200,4(%ecx,%edx, 1)
 	ltr	%dx
 
-	/* Set curlwp. */
-	movl	%edi,CPUVAR(CURLWP)
-
 	/* Don't bother with the rest if switching to a system process. */
 	testl	$LW_SYSTEM,L_FLAG(%edi)
 	jnz	4f
 
+	/* Restore thread-private %fs/%gs descriptors. */
+	movl	PCB_FSD(%ebx), %eax
+	movl	PCB_FSD+4(%ebx), %edx
+	movl	%eax, (GUFS_SEL*8)(%ecx)
+	movl	%edx, (GUFS_SEL*8+4)(%ecx)
+	movl	PCB_GSD(%ebx), %eax
+	movl	PCB_GSD+4(%ebx), %edx
+	movl	%eax, (GUGS_SEL*8)(%ecx)
+	movl	%edx, (GUGS_SEL*8+4)(%ecx)
+
 	/* Is this process using RAS (restartable atomic sequences)? */
 	movl	L_PROC(%edi),%eax
 	cmpl	$0,P_RASLIST(%eax)
@@ -896,10 +911,9 @@ syscall1:
 	pushl	$4f
 	call	_C_LABEL(printf)
 	addl	$4,%esp
-#ifdef DDB
-	int	$3
-#endif /* DDB */
-	movl	$IPL_NONE,CPUVAR(ILEVEL)
+	pushl	$IPL_NONE
+	call	_C_LABEL(spllower)
+	addl	$4,%esp
 	jmp	.Lsyscall_checkast
 4:	.asciz	"WARNING: SPL NOT LOWERED ON SYSCALL EXIT\n"
 5:	.asciz	"WARNING: SPL NOT ZERO ON SYSCALL ENTRY\n"