Module Name: src
Committed By: simonb
Date: Wed Apr 7 02:59:01 UTC 2021
Modified Files:
src/sys/arch/mips/mips: trap.c
Log Message:
Basic dtrace trap support.
Mostly from FreeBSD.
To generate a diff of this commit:
cvs rdiff -u -r1.260 -r1.261 src/sys/arch/mips/mips/trap.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/mips/mips/trap.c
diff -u src/sys/arch/mips/mips/trap.c:1.260 src/sys/arch/mips/mips/trap.c:1.261
--- src/sys/arch/mips/mips/trap.c:1.260 Mon Mar 29 03:22:17 2021
+++ src/sys/arch/mips/mips/trap.c Wed Apr 7 02:59:01 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: trap.c,v 1.260 2021/03/29 03:22:17 simonb Exp $ */
+/* $NetBSD: trap.c,v 1.261 2021/04/07 02:59:01 simonb Exp $ */
/*
* Copyright (c) 1988 University of Utah.
@@ -39,7 +39,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.260 2021/03/29 03:22:17 simonb Exp $");
+__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.261 2021/04/07 02:59:01 simonb Exp $");
#include "opt_cputype.h" /* which mips CPU levels do we support? */
#include "opt_ddb.h"
@@ -83,6 +83,16 @@ __KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.2
#include <sys/kgdb.h>
#endif
+#ifdef KDTRACE_HOOKS
+#include <sys/dtrace_bsd.h>
+
+/* Not used for now, but needed for dtrace/fbt modules */
+dtrace_doubletrap_func_t dtrace_doubletrap_func = NULL;
+dtrace_trap_func_t dtrace_trap_func = NULL;
+
+int (* dtrace_invop_jump_addr)(struct trapframe *);
+#endif /* KDTRACE_HOOKS */
+
const char * const trap_names[] = {
"external interrupt",
"TLB modification",
@@ -187,6 +197,30 @@ trap(uint32_t status, uint32_t cause, va
LWP_CACHE_CREDS(l, p);
}
+#ifdef KDTRACE_HOOKS
+ /*
+ * A trap can occur while DTrace executes a probe. Before
+ * executing the probe, DTrace blocks re-scheduling and sets
+ * a flag in its per-cpu flags to indicate that it doesn't
+ * want to fault. On returning from the probe, the no-fault
+ * flag is cleared and finally re-scheduling is enabled.
+ *
+ * If the DTrace kernel module has registered a trap handler,
+ * call it and if it returns non-zero, assume that it has
+ * handled the trap and modified the trap frame so that this
+ * function can return normally.
+ */
+ /*
+ * XXXDTRACE: add pid probe handler here (if ever)
+ */
+ if (!USERMODE(status)) {
+ if ((dtrace_trap_func != NULL) &&
+ ((*dtrace_trap_func)(tf, type) != 0)) {
+ return;
+ }
+ }
+#endif /* KDTRACE_HOOKS */
+
switch (type) {
default:
dopanic:
@@ -518,8 +552,15 @@ trap(uint32_t status, uint32_t cause, va
}
break; /* SIGNAL */
- case T_WATCH:
case T_BREAK:
+#ifdef KDTRACE_HOOKS
+ if ((dtrace_invop_jump_addr != NULL) &&
+ (dtrace_invop_jump_addr(tf) == 0)) {
+ return;
+ }
+#endif /* KDTRACE_HOOKS */
+ /* FALLTHROUGH */
+ case T_WATCH:
#if defined(DDB)
kdb_trap(type, &tf->tf_registers);
return; /* KERN */
@@ -805,16 +846,6 @@ mips_singlestep(struct lwp *l)
return 0;
}
-#ifdef KDTRACE_HOOKS
-#include <sys/dtrace_bsd.h>
-
-/* Not used for now, but needed for dtrace/fbt modules */
-dtrace_doubletrap_func_t dtrace_doubletrap_func = NULL;
-dtrace_trap_func_t dtrace_trap_func = NULL;
-
-int (* dtrace_invop_jump_addr)(struct trapframe *);
-#endif /* KDTRACE_HOOKS */
-
#ifdef TRAP_SIGDEBUG
static void
frame_dump(const struct trapframe *tf, struct pcb *pcb)
