From 85f1c223b39c92c49e8b7c6c7ad39d3e42a27574 Mon Sep 17 00:00:00 2001
From: bsd <bsd@FreeBSD.org>
Date: Sun, 20 Feb 2000 20:51:23 +0000
Subject: Don't forget to reset the hardware debug registers when a process
 that was using them exits.

Don't allow a user process to cause the kernel to take a TRCTRAP on a
user space address.

Reviewed by:	jlemon, sef
Approved by:	jkh
---
 sys/amd64/amd64/vm_machdep.c | 7 +++++++
 1 file changed, 7 insertions(+)

(limited to 'sys/amd64/amd64/vm_machdep.c')

diff --git a/sys/amd64/amd64/vm_machdep.c b/sys/amd64/amd64/vm_machdep.c
index d7fa73b1..cdcc278 100644
--- a/sys/amd64/amd64/vm_machdep.c
+++ b/sys/amd64/amd64/vm_machdep.c
@@ -246,6 +246,13 @@ cpu_exit(p)
 #ifdef USER_LDT
 	user_ldt_free(pcb);
 #endif
+        if (pcb->pcb_flags & PCB_DBREGS) {
+                /*
+                 * disable all hardware breakpoints
+                 */
+                reset_dbregs();
+                pcb->pcb_flags &= ~PCB_DBREGS;
+        }
 	cnt.v_swtch++;
 	cpu_switch(p);
 	panic("cpu_exit");
-- 
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