Register an interrupt vector for DTrace return probes. There is some

code missing in lapic to make sure that we don't overwrite this entry,
but this will be done on a sequent commit.

Sponsored by:	The FreeBSD Foundation

6 files changed, 25 insertions, 1 deletions

diff --git a/sys/amd64/amd64/exception.S b/sys/amd64/amd64/exception.S
index c18f27f..37e89a00 100644
--- a/sys/amd64/amd64/exception.S
+++ b/sys/amd64/amd64/exception.S
@@ -108,6 +108,10 @@ IDTVEC(dbg)
 	TRAP_NOEN(T_TRCTRAP)
 IDTVEC(bpt)
 	TRAP_NOEN(T_BPTFLT)
+#ifdef KDTRACE_HOOKS
+IDTVEC(dtrace_ret)
+	TRAP_NOEN(T_DTRACE_RET)
+#endif
 
 /* Regular traps; The cpu does not supply tf_err for these. */
 #define	TRAP(a)	 \
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index 6bec71b..fe68600 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -54,6 +54,7 @@ __FBSDID("$FreeBSD$");
 #include "opt_msgbuf.h"
 #include "opt_perfmon.h"
 #include "opt_sched.h"
+#include "opt_kdtrace.h"
 
 #include <sys/param.h>
 #include <sys/proc.h>
@@ -1089,6 +1090,9 @@ extern inthand_t
 	IDTVEC(tss), IDTVEC(missing), IDTVEC(stk), IDTVEC(prot),
 	IDTVEC(page), IDTVEC(mchk), IDTVEC(rsvd), IDTVEC(fpu), IDTVEC(align),
 	IDTVEC(xmm), IDTVEC(dblfault),
+#ifdef KDTRACE_HOOKS
+	IDTVEC(dtrace_ret),
+#endif
 	IDTVEC(fast_syscall), IDTVEC(fast_syscall32);
 
 #ifdef DDB
@@ -1617,6 +1621,9 @@ hammer_time(u_int64_t modulep, u_int64_t physfree)
 	setidt(IDT_AC, &IDTVEC(align), SDT_SYSIGT, SEL_KPL, 0);
 	setidt(IDT_MC, &IDTVEC(mchk),  SDT_SYSIGT, SEL_KPL, 0);
 	setidt(IDT_XF, &IDTVEC(xmm), SDT_SYSIGT, SEL_KPL, 0);
+#ifdef KDTRACE_HOOKS
+	setidt(IDT_DTRACE_RET, &IDTVEC(dtrace_ret), SDT_SYSIGT, SEL_UPL, 0);
+#endif
 
 	r_idt.rd_limit = sizeof(idt0) - 1;
 	r_idt.rd_base = (long) idt;
diff --git a/sys/amd64/include/segments.h b/sys/amd64/include/segments.h
index 282c1ae..22dc95a 100644
--- a/sys/amd64/include/segments.h
+++ b/sys/amd64/include/segments.h
@@ -214,6 +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 */
 
 /*
  * Entries in the Global Descriptor Table (GDT)
diff --git a/sys/i386/i386/exception.s b/sys/i386/i386/exception.s
index 575b98d..13562fa 100644
--- a/sys/i386/i386/exception.s
+++ b/sys/i386/i386/exception.s
@@ -108,6 +108,8 @@ IDTVEC(nmi)
 	pushl $0; TRAP(T_NMI)
 IDTVEC(bpt)
 	pushl $0; TRAP(T_BPTFLT)
+IDTVEC(dtrace_ret)
+	pushl $0; TRAP(T_DTRACE_RET)
 IDTVEC(ofl)
 	pushl $0; TRAP(T_OFLOW)
 IDTVEC(bnd)
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index 872d09b..ef229ca 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -54,6 +54,7 @@ __FBSDID("$FreeBSD$");
 #include "opt_npx.h"
 #include "opt_perfmon.h"
 #include "opt_xbox.h"
+#include "opt_kdtrace.h"
 
 #include <sys/param.h>
 #include <sys/proc.h>
@@ -1876,7 +1877,11 @@ extern inthand_t
 	IDTVEC(bnd), IDTVEC(ill), IDTVEC(dna), IDTVEC(fpusegm),
 	IDTVEC(tss), IDTVEC(missing), IDTVEC(stk), IDTVEC(prot),
 	IDTVEC(page), IDTVEC(mchk), IDTVEC(rsvd), IDTVEC(fpu), IDTVEC(align),
-	IDTVEC(xmm), IDTVEC(lcall_syscall), IDTVEC(int0x80_syscall);
+	IDTVEC(xmm),
+#ifdef KDTRACE_HOOKS
+	IDTVEC(dtrace_ret),
+#endif
+	IDTVEC(lcall_syscall), IDTVEC(int0x80_syscall);
 
 #ifdef DDB
 /*
@@ -2825,6 +2830,10 @@ init386(first)
 	    GSEL(GCODE_SEL, SEL_KPL));
  	setidt(IDT_SYSCALL, &IDTVEC(int0x80_syscall), SDT_SYS386TGT, SEL_UPL,
 	    GSEL(GCODE_SEL, SEL_KPL));
+#ifdef KDTRACE_HOOKS
+	setidt(IDT_DTRACE_RET, &IDTVEC(dtrace_ret), SDT_SYS386TGT, SEL_UPL,
+	    GSEL(GCODE_SEL, SEL_KPL));
+#endif
 
 	r_idt.rd_limit = sizeof(idt0) - 1;
 	r_idt.rd_base = (int) idt;
diff --git a/sys/i386/include/segments.h b/sys/i386/include/segments.h
index 0b12f62..deeaf76 100644
--- a/sys/i386/include/segments.h
+++ b/sys/i386/include/segments.h
@@ -207,6 +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 */
 
 /*
  * Entries in the Global Descriptor Table (GDT)