Author: markj
Date: Fri Mar 10 18:52:37 2017
New Revision: 315012
URL: https://svnweb.freebsd.org/changeset/base/315012
Log:
MFC r313841, r313850:
Prevent CPU migration when checking the DTrace nofault flag on x86.
Modified:
stable/10/sys/cddl/dev/dtrace/amd64/dtrace_subr.c
stable/10/sys/cddl/dev/dtrace/i386/dtrace_subr.c
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sys/cddl/dev/dtrace/amd64/dtrace_subr.c
==============================================================================
--- stable/10/sys/cddl/dev/dtrace/amd64/dtrace_subr.c Fri Mar 10 18:51:47
2017 (r315011)
+++ stable/10/sys/cddl/dev/dtrace/amd64/dtrace_subr.c Fri Mar 10 18:52:37
2017 (r315012)
@@ -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 uintptr_t dtrace_in_probe_addr;
@@ -466,6 +468,8 @@ 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
@@ -476,7 +480,12 @@ 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/10/sys/cddl/dev/dtrace/i386/dtrace_subr.c
==============================================================================
--- stable/10/sys/cddl/dev/dtrace/i386/dtrace_subr.c Fri Mar 10 18:51:47
2017 (r315011)
+++ stable/10/sys/cddl/dev/dtrace/i386/dtrace_subr.c Fri Mar 10 18:52:37
2017 (r315012)
@@ -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;
@@ -475,6 +477,8 @@ 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
@@ -485,7 +489,12 @@ 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.
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