svn commit: r315011 - in stable/11/sys/cddl/dev/dtrace: amd64 i386

[Mark Johnston]

Author: markj
Date: Fri Mar 10 18:51:47 2017
New Revision: 315011
URL: https://svnweb.freebsd.org/changeset/base/315011

Log:
  MFC r313841, r313850:
  Prevent CPU migration when checking the DTrace nofault flag on x86.

Modified:
  stable/11/sys/cddl/dev/dtrace/amd64/dtrace_subr.c
  stable/11/sys/cddl/dev/dtrace/i386/dtrace_subr.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/cddl/dev/dtrace/amd64/dtrace_subr.c
==============================================================================
--- stable/11/sys/cddl/dev/dtrace/amd64/dtrace_subr.c	Fri Mar 10 17:37:55 2017	(r315010)
+++ stable/11/sys/cddl/dev/dtrace/amd64/dtrace_subr.c	Fri Mar 10 18:51:47 2017	(r315011)
@@ -41,7 +41,9 @@
 #include <sys/dtrace_impl.h>
 #include <sys/dtrace_bsd.h>
 #include <machine/clock.h>
+#include <machine/cpufunc.h>
 #include <machine/frame.h>
+#include <machine/psl.h>
 #include <vm/pmap.h>
 
 extern void dtrace_getnanotime(struct timespec *tsp);
@@ -384,6 +386,8 @@ dtrace_gethrestime(void)
 int
 dtrace_trap(struct trapframe *frame, u_int type)
 {
+	uint16_t nofault;
+
 	/*
 	 * A trap can occur while DTrace executes a probe. Before
 	 * executing the probe, DTrace blocks re-scheduling and sets
@@ -393,7 +397,12 @@ dtrace_trap(struct trapframe *frame, u_i
 	 *
 	 * Check if DTrace has enabled 'no-fault' mode:
 	 */
-	if ((cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT) != 0) {
+	sched_pin();
+	nofault = cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT;
+	sched_unpin();
+	if (nofault) {
+		KASSERT((read_rflags() & PSL_I) == 0, ("interrupts enabled"));
+
 		/*
 		 * There are only a couple of trap types that are expected.
 		 * All the rest will be handled in the usual way.

Modified: stable/11/sys/cddl/dev/dtrace/i386/dtrace_subr.c
==============================================================================
--- stable/11/sys/cddl/dev/dtrace/i386/dtrace_subr.c	Fri Mar 10 17:37:55 2017	(r315010)
+++ stable/11/sys/cddl/dev/dtrace/i386/dtrace_subr.c	Fri Mar 10 18:51:47 2017	(r315011)
@@ -42,7 +42,9 @@
 #include <sys/dtrace_impl.h>
 #include <sys/dtrace_bsd.h>
 #include <machine/clock.h>
+#include <machine/cpufunc.h>
 #include <machine/frame.h>
+#include <machine/psl.h>
 #include <vm/pmap.h>
 
 extern uintptr_t 	kernelbase;
@@ -386,6 +388,8 @@ dtrace_gethrestime(void)
 int
 dtrace_trap(struct trapframe *frame, u_int type)
 {
+	uint16_t nofault;
+
 	/*
 	 * A trap can occur while DTrace executes a probe. Before
 	 * executing the probe, DTrace blocks re-scheduling and sets
@@ -395,7 +399,12 @@ dtrace_trap(struct trapframe *frame, u_i
 	 *
 	 * Check if DTrace has enabled 'no-fault' mode:
 	 */
-	if ((cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT) != 0) {
+	sched_pin();
+	nofault = cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT;
+	sched_unpin();
+	if (nofault) {
+		KASSERT((read_eflags() & PSL_I) == 0, ("interrupts enabled"));
+
 		/*
 		 * There are only a couple of trap types that are expected.
 		 * All the rest will be handled in the usual way.