From 8e69ce0726eacc9d39d7fc4519b23892a5440443 Mon Sep 17 00:00:00 2001
From: yamt <yamt@NetBSD.org>
Date: Fri, 25 May 2007 15:09:50 +0000
Subject: [PATCH] dumpsys: build a fake switchframe for postmortem debugging.
 reviewed by Frank van der Linden.

---
 sys/arch/amd64/amd64/locore.S  | 22 +++++++++++++++++++++-
 sys/arch/amd64/amd64/machdep.c | 10 ++++------
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/sys/arch/amd64/amd64/locore.S b/sys/arch/amd64/amd64/locore.S
index 2409371f68f0..3d84ee1a2d36 100644
--- a/sys/arch/amd64/amd64/locore.S
+++ b/sys/arch/amd64/amd64/locore.S
@@ -1,4 +1,4 @@
-/*	$NetBSD: locore.S,v 1.24 2007/05/21 08:10:38 fvdl Exp $	*/
+/*	$NetBSD: locore.S,v 1.25 2007/05/25 15:09:50 yamt Exp $	*/
 
 /*
  * Copyright-o-rama!
@@ -709,6 +709,26 @@ ENTRY(longjmp)
 	movl	$1,%eax
 	ret
 
+ENTRY(dumpsys)
+	# mimic cpu_switchto() for postmortem debugging.
+
+	# build a fake switch frame.
+	pushq	%rbx
+	pushq	%r12
+	pushq	%r13
+	pushq	%r14
+	pushq	%r15
+	
+	# save a context.
+	movq	$dumppcb, %rax
+	movq	%rsp, PCB_RSP(%rax)
+	movq	%rbp, PCB_RBP(%rax)
+
+	call	_C_LABEL(dodumpsys)
+
+	addq	$(5*8), %rsp	# sizeof(switchframe) - sizeof(%rip)
+	ret
+
 /*
  * struct lwp *cpu_switchto(struct lwp *, struct lwp *)
  *
diff --git a/sys/arch/amd64/amd64/machdep.c b/sys/arch/amd64/amd64/machdep.c
index b174c704de1a..128485ad3d82 100644
--- a/sys/arch/amd64/amd64/machdep.c
+++ b/sys/arch/amd64/amd64/machdep.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: machdep.c,v 1.58 2007/05/21 08:10:38 fvdl Exp $	*/
+/*	$NetBSD: machdep.c,v 1.59 2007/05/25 15:09:50 yamt Exp $	*/
 
 /*-
  * Copyright (c) 1996, 1997, 1998, 2000, 2006, 2007
@@ -73,7 +73,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.58 2007/05/21 08:10:38 fvdl Exp $");
+__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.59 2007/05/25 15:09:50 yamt Exp $");
 
 #include "opt_user_ldt.h"
 #include "opt_ddb.h"
@@ -230,6 +230,7 @@ int	cpu_dump(void);
 int	cpu_dumpsize(void);
 u_long	cpu_dump_mempagecnt(void);
 void	dumpsys(void);
+void	dodumpsys(void);
 void	init_x86_64(paddr_t);
 
 /*
@@ -724,7 +725,7 @@ reserve_dumppages(vaddr_t p)
 }
 
 void
-dumpsys(void)
+dodumpsys(void)
 {
 	const struct bdevsw *bdev;
 	u_long totalbytesleft, bytes, i, n, memseg;
@@ -734,9 +735,6 @@ dumpsys(void)
 	int (*dump)(dev_t, daddr_t, void *, size_t);
 	int error;
 
-	/* Save registers. */
-	savectx(&dumppcb);
-
 	if (dumpdev == NODEV)
 		return;
 	bdev = bdevsw_lookup(dumpdev);