Fix the DTrace pid return trap interrupt vector. Previously we were using

31, but that vector is reserved.

Without this fix, running dtrace -p <pid> would either cause the target
process to crash or the kernel to page fault.

Obtained from:	rpaulo
MFC after:	3days

6 files changed, 25 insertions, 21 deletions

diff --git a/sys/amd64/amd64/trap.c b/sys/amd64/amd64/trap.c
index 9c72a69..c5f0a71 100644
--- a/sys/amd64/amd64/trap.c
+++ b/sys/amd64/amd64/trap.c
@@ -125,7 +125,7 @@ void dblfault_handler(struct trapframe *frame);
 static int trap_pfault(struct trapframe *, int);
 static void trap_fatal(struct trapframe *, vm_offset_t);
 
-#define MAX_TRAP_MSG		30
+#define MAX_TRAP_MSG		33
 static char *trap_msg[] = {
 	"",					/*  0 unused */
 	"privileged instruction fault",		/*  1 T_PRIVINFLT */
@@ -158,6 +158,9 @@ static char *trap_msg[] = {
 	"machine check trap",			/* 28 T_MCHK */
 	"SIMD floating-point exception",	/* 29 T_XMMFLT */
 	"reserved (unknown) fault",		/* 30 T_RESERVED */
+	"",					/* 31 unused (reserved) */
+	"DTrace pid return trap",		/* 32 T_DTRACE_RET */
+	"DTrace fasttrap probe trap",		/* 33 T_DTRACE_PROBE */
 };
 
 #ifdef KDB
@@ -245,28 +248,26 @@ trap(struct trapframe *frame)
 	 * handled the trap and modified the trap frame so that this
 	 * function can return normally.
 	 */
-	if (dtrace_trap_func != NULL)
-		if ((*dtrace_trap_func)(frame, type))
-			goto out;
 	if (type == T_DTRACE_PROBE || type == T_DTRACE_RET ||
 	    type == T_BPTFLT) {
 		struct reg regs;
-		
+
 		fill_frame_regs(frame, &regs);
 		if (type == T_DTRACE_PROBE &&
 		    dtrace_fasttrap_probe_ptr != NULL &&
 		    dtrace_fasttrap_probe_ptr(&regs) == 0)
-				goto out;
-		if (type == T_BPTFLT &&
+			goto out;
+		else if (type == T_BPTFLT &&
 		    dtrace_pid_probe_ptr != NULL &&
 		    dtrace_pid_probe_ptr(&regs) == 0)
-				goto out;
-		if (type == T_DTRACE_RET &&
+			goto out;
+		else if (type == T_DTRACE_RET &&
 		    dtrace_return_probe_ptr != NULL &&
 		    dtrace_return_probe_ptr(&regs) == 0)
 			goto out;
-
 	}
+	if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type))
+		goto out;
 #endif
 
 	if ((frame->tf_rflags & PSL_I) == 0) {
diff --git a/sys/amd64/include/segments.h b/sys/amd64/include/segments.h
index 22dc95a..2796511 100644
--- a/sys/amd64/include/segments.h
+++ b/sys/amd64/include/segments.h
@@ -214,7 +214,7 @@ struct region_descriptor {
 #define	IDT_XF		19	/* #XF: SIMD Floating-Point Exception */
 #define	IDT_IO_INTS	NRSVIDT	/* Base of IDT entries for I/O interrupts. */
 #define	IDT_SYSCALL	0x80	/* System Call Interrupt Vector */
-#define	IDT_DTRACE_RET	0x92	/* DTrace pid provider Interrupt Vector */
+#define	IDT_DTRACE_RET	0x20	/* DTrace pid provider Interrupt Vector */
 
 /*
  * Entries in the Global Descriptor Table (GDT)
diff --git a/sys/amd64/include/trap.h b/sys/amd64/include/trap.h
index d8e36b5..a395d62 100644
--- a/sys/amd64/include/trap.h
+++ b/sys/amd64/include/trap.h
@@ -62,8 +62,8 @@
 #define	T_MCHK		28	/* machine check trap */
 #define	T_XMMFLT	29	/* SIMD floating-point exception */
 #define	T_RESERVED	30	/* reserved (unknown) */
-#define	T_DTRACE_RET	31	/* DTrace pid return */
-#define	T_DTRACE_PROBE	32	/* DTrace fasttrap probe */
+#define	T_DTRACE_RET	32	/* DTrace pid return */
+#define	T_DTRACE_PROBE	33	/* DTrace fasttrap probe */
 
 /* XXX most of the following codes aren't used, but could be. */
 
diff --git a/sys/i386/i386/trap.c b/sys/i386/i386/trap.c
index 5006f41..b241757 100644
--- a/sys/i386/i386/trap.c
+++ b/sys/i386/i386/trap.c
@@ -136,7 +136,7 @@ void dblfault_handler(void);
 
 extern inthand_t IDTVEC(lcall_syscall);
 
-#define MAX_TRAP_MSG		30
+#define MAX_TRAP_MSG		33
 static char *trap_msg[] = {
 	"",					/*  0 unused */
 	"privileged instruction fault",		/*  1 T_PRIVINFLT */
@@ -169,6 +169,10 @@ static char *trap_msg[] = {
 	"machine check trap",			/* 28 T_MCHK */
 	"SIMD floating-point exception",	/* 29 T_XMMFLT */
 	"reserved (unknown) fault",		/* 30 T_RESERVED */
+	"",					/* 31 unused (reserved) */
+	"DTrace pid return trap",               /* 32 T_DTRACE_RET */
+	"DTrace fasttrap probe trap",           /* 33 T_DTRACE_PROBE */
+
 };
 
 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
@@ -265,10 +269,6 @@ trap(struct trapframe *frame)
 	 * handled the trap and modified the trap frame so that this
 	 * function can return normally.
 	 */
-	if ((type == T_PROTFLT || type == T_PAGEFLT) &&
-	    dtrace_trap_func != NULL)
-		if ((*dtrace_trap_func)(frame, type))
-			goto out;
 	if (type == T_DTRACE_PROBE || type == T_DTRACE_RET ||
 	    type == T_BPTFLT) {
 		struct reg regs;
@@ -287,6 +287,9 @@ trap(struct trapframe *frame)
 		    dtrace_return_probe_ptr(&regs) == 0)
 			goto out;
 	}
+	if ((type == T_PROTFLT || type == T_PAGEFLT) &&
+	    dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type))
+		goto out;
 #endif
 
 	if ((frame->tf_eflags & PSL_I) == 0) {
diff --git a/sys/i386/include/segments.h b/sys/i386/include/segments.h
index 1c1ddee..9e65c3c 100644
--- a/sys/i386/include/segments.h
+++ b/sys/i386/include/segments.h
@@ -207,7 +207,7 @@ struct region_descriptor {
 #define	IDT_XF		19	/* #XF: SIMD Floating-Point Exception */
 #define	IDT_IO_INTS	NRSVIDT	/* Base of IDT entries for I/O interrupts. */
 #define	IDT_SYSCALL	0x80	/* System Call Interrupt Vector */
-#define	IDT_DTRACE_RET	0x92	/* DTrace pid provider Interrupt Vector */
+#define	IDT_DTRACE_RET	0x20	/* DTrace pid provider Interrupt Vector */
 
 /*
  * Entries in the Global Descriptor Table (GDT)
diff --git a/sys/i386/include/trap.h b/sys/i386/include/trap.h
index d8e36b5..a395d62 100644
--- a/sys/i386/include/trap.h
+++ b/sys/i386/include/trap.h
@@ -62,8 +62,8 @@
 #define	T_MCHK		28	/* machine check trap */
 #define	T_XMMFLT	29	/* SIMD floating-point exception */
 #define	T_RESERVED	30	/* reserved (unknown) */
-#define	T_DTRACE_RET	31	/* DTrace pid return */
-#define	T_DTRACE_PROBE	32	/* DTrace fasttrap probe */
+#define	T_DTRACE_RET	32	/* DTrace pid return */
+#define	T_DTRACE_PROBE	33	/* DTrace fasttrap probe */
 
 /* XXX most of the following codes aren't used, but could be. */