diff --git a/sys/amd64/amd64/exception.S b/sys/amd64/amd64/exception.S
index ddfd38834b24..28579ac8e96a 100644
--- a/sys/amd64/amd64/exception.S
+++ b/sys/amd64/amd64/exception.S
@@ -76,18 +76,6 @@
  * must restore them prior to calling 'iret'.  The cpu adjusts the %cs and
  * %ss segment registers, but does not mess with %ds, %es, or %fs.  Thus we
  * must load them with appropriate values for supervisor mode operation.
- *
- * On entry to a trap or interrupt WE DO NOT OWN THE MP LOCK.  This means
- * that we must be careful in regards to accessing global variables.  We
- * save (push) the current cpl (our software interrupt disable mask), call
- * the trap function, then call doreti to restore the cpl and deal with
- * ASTs (software interrupts).  doreti will determine if the restoration
- * of the cpl unmasked any pending interrupts and will issue those interrupts
- * synchronously prior to doing the iret.
- *
- * At the moment we must own the MP lock to do any cpl manipulation, which
- * means we must own it prior to  calling doreti.  The syscall case attempts
- * to avoid this by handling a reduced set of cases itself and iret'ing.
  */
 #define	IDTVEC(name)	ALIGN_TEXT; .globl __CONCAT(X,name); \
 			.type __CONCAT(X,name),@function; __CONCAT(X,name):
@@ -197,9 +185,6 @@ calltrap:
  * final spot. It has to be done this way because esp can't be just
  * temporarily altered for the pushfl - an interrupt might come in
  * and clobber the saved cs/eip.
- *
- * We do not obtain the MP lock, but the call to syscall might.  If it
- * does it will release the lock prior to returning.
  */
 	SUPERALIGN_TEXT
 IDTVEC(lcall_syscall)
@@ -214,9 +199,6 @@ IDTVEC(lcall_syscall)
  * Even though the name says 'int0x80', this is actually a TGT (trap gate)
  * rather then an IGT (interrupt gate).  Thus interrupts are enabled on
  * entry just as they are for a normal syscall.
- *
- * We do not obtain the MP lock, but the call to syscall might.  If it
- * does it will release the lock prior to returning.
  */
 	SUPERALIGN_TEXT
 IDTVEC(int0x80_syscall)
diff --git a/sys/amd64/amd64/exception.s b/sys/amd64/amd64/exception.s
index ddfd38834b24..28579ac8e96a 100644
--- a/sys/amd64/amd64/exception.s
+++ b/sys/amd64/amd64/exception.s
@@ -76,18 +76,6 @@
  * must restore them prior to calling 'iret'.  The cpu adjusts the %cs and
  * %ss segment registers, but does not mess with %ds, %es, or %fs.  Thus we
  * must load them with appropriate values for supervisor mode operation.
- *
- * On entry to a trap or interrupt WE DO NOT OWN THE MP LOCK.  This means
- * that we must be careful in regards to accessing global variables.  We
- * save (push) the current cpl (our software interrupt disable mask), call
- * the trap function, then call doreti to restore the cpl and deal with
- * ASTs (software interrupts).  doreti will determine if the restoration
- * of the cpl unmasked any pending interrupts and will issue those interrupts
- * synchronously prior to doing the iret.
- *
- * At the moment we must own the MP lock to do any cpl manipulation, which
- * means we must own it prior to  calling doreti.  The syscall case attempts
- * to avoid this by handling a reduced set of cases itself and iret'ing.
  */
 #define	IDTVEC(name)	ALIGN_TEXT; .globl __CONCAT(X,name); \
 			.type __CONCAT(X,name),@function; __CONCAT(X,name):
@@ -197,9 +185,6 @@ calltrap:
  * final spot. It has to be done this way because esp can't be just
  * temporarily altered for the pushfl - an interrupt might come in
  * and clobber the saved cs/eip.
- *
- * We do not obtain the MP lock, but the call to syscall might.  If it
- * does it will release the lock prior to returning.
  */
 	SUPERALIGN_TEXT
 IDTVEC(lcall_syscall)
@@ -214,9 +199,6 @@ IDTVEC(lcall_syscall)
  * Even though the name says 'int0x80', this is actually a TGT (trap gate)
  * rather then an IGT (interrupt gate).  Thus interrupts are enabled on
  * entry just as they are for a normal syscall.
- *
- * We do not obtain the MP lock, but the call to syscall might.  If it
- * does it will release the lock prior to returning.
  */
 	SUPERALIGN_TEXT
 IDTVEC(int0x80_syscall)
diff --git a/sys/amd64/amd64/trap.c b/sys/amd64/amd64/trap.c
index a84a4f24302d..11effc39be57 100644
--- a/sys/amd64/amd64/trap.c
+++ b/sys/amd64/amd64/trap.c
@@ -1012,15 +1012,9 @@ int trapwrite(addr)
 }
 
 /*
- *	syscall -	MP aware system call request C handler
+ *	syscall -	system call request C handler
  *
- *	A system call is essentially treated as a trap except that the
- *	MP lock is not held on entry or return.  We are responsible for
- *	obtaining the MP lock if necessary and for handling ASTs
- *	(e.g. a task switch) prior to return.
- *
- *	In general, only simple access and manipulation of curproc and
- *	the current stack is allowed without having to hold MP lock.
+ *	A system call is essentially treated as a trap.
  */
 void
 syscall(frame)
@@ -1103,7 +1097,7 @@ syscall(frame)
 	}
 
 	/*
-	 * Try to run the syscall without the MP lock if the syscall
+	 * Try to run the syscall without Giant if the syscall
 	 * is MP safe.
 	 */
 	if ((callp->sy_narg & SYF_MPSAFE) == 0) {
@@ -1112,7 +1106,7 @@ syscall(frame)
 
 #ifdef KTRACE
 	/*
-	 * We have to obtain the MP lock no matter what if 
+	 * We have to obtain Giant no matter what if 
 	 * we are ktracing
 	 */
 	if (KTRPOINT(p, KTR_SYSCALL)) {
@@ -1124,13 +1118,10 @@ syscall(frame)
 	p->p_retval[0] = 0;
 	p->p_retval[1] = frame.tf_edx;
 
-	STOPEVENT(p, S_SCE, narg);	/* MP aware */
+	STOPEVENT(p, S_SCE, narg);
 
 	error = (*callp->sy_call)(p, args);
 
-	/*
-	 * MP SAFE (we may or may not have the MP lock at this point)
-	 */
 	switch (error) {
 	case 0:
 		frame.tf_eax = p->p_retval[0];
@@ -1163,7 +1154,7 @@ bad:
 	}
 
 	/*
-	 * Traced syscall.  trapsignal() is not MP aware.
+	 * Traced syscall.
 	 */
 	if ((frame.tf_eflags & PSL_T) && !(frame.tf_eflags & PSL_VM)) {
 		if (!mtx_owned(&Giant))
diff --git a/sys/i386/i386/exception.s b/sys/i386/i386/exception.s
index ddfd38834b24..28579ac8e96a 100644
--- a/sys/i386/i386/exception.s
+++ b/sys/i386/i386/exception.s
@@ -76,18 +76,6 @@
  * must restore them prior to calling 'iret'.  The cpu adjusts the %cs and
  * %ss segment registers, but does not mess with %ds, %es, or %fs.  Thus we
  * must load them with appropriate values for supervisor mode operation.
- *
- * On entry to a trap or interrupt WE DO NOT OWN THE MP LOCK.  This means
- * that we must be careful in regards to accessing global variables.  We
- * save (push) the current cpl (our software interrupt disable mask), call
- * the trap function, then call doreti to restore the cpl and deal with
- * ASTs (software interrupts).  doreti will determine if the restoration
- * of the cpl unmasked any pending interrupts and will issue those interrupts
- * synchronously prior to doing the iret.
- *
- * At the moment we must own the MP lock to do any cpl manipulation, which
- * means we must own it prior to  calling doreti.  The syscall case attempts
- * to avoid this by handling a reduced set of cases itself and iret'ing.
  */
 #define	IDTVEC(name)	ALIGN_TEXT; .globl __CONCAT(X,name); \
 			.type __CONCAT(X,name),@function; __CONCAT(X,name):
@@ -197,9 +185,6 @@ calltrap:
  * final spot. It has to be done this way because esp can't be just
  * temporarily altered for the pushfl - an interrupt might come in
  * and clobber the saved cs/eip.
- *
- * We do not obtain the MP lock, but the call to syscall might.  If it
- * does it will release the lock prior to returning.
  */
 	SUPERALIGN_TEXT
 IDTVEC(lcall_syscall)
@@ -214,9 +199,6 @@ IDTVEC(lcall_syscall)
  * Even though the name says 'int0x80', this is actually a TGT (trap gate)
  * rather then an IGT (interrupt gate).  Thus interrupts are enabled on
  * entry just as they are for a normal syscall.
- *
- * We do not obtain the MP lock, but the call to syscall might.  If it
- * does it will release the lock prior to returning.
  */
 	SUPERALIGN_TEXT
 IDTVEC(int0x80_syscall)
diff --git a/sys/i386/i386/trap.c b/sys/i386/i386/trap.c
index a84a4f24302d..11effc39be57 100644
--- a/sys/i386/i386/trap.c
+++ b/sys/i386/i386/trap.c
@@ -1012,15 +1012,9 @@ int trapwrite(addr)
 }
 
 /*
- *	syscall -	MP aware system call request C handler
+ *	syscall -	system call request C handler
  *
- *	A system call is essentially treated as a trap except that the
- *	MP lock is not held on entry or return.  We are responsible for
- *	obtaining the MP lock if necessary and for handling ASTs
- *	(e.g. a task switch) prior to return.
- *
- *	In general, only simple access and manipulation of curproc and
- *	the current stack is allowed without having to hold MP lock.
+ *	A system call is essentially treated as a trap.
  */
 void
 syscall(frame)
@@ -1103,7 +1097,7 @@ syscall(frame)
 	}
 
 	/*
-	 * Try to run the syscall without the MP lock if the syscall
+	 * Try to run the syscall without Giant if the syscall
 	 * is MP safe.
 	 */
 	if ((callp->sy_narg & SYF_MPSAFE) == 0) {
@@ -1112,7 +1106,7 @@ syscall(frame)
 
 #ifdef KTRACE
 	/*
-	 * We have to obtain the MP lock no matter what if 
+	 * We have to obtain Giant no matter what if 
 	 * we are ktracing
 	 */
 	if (KTRPOINT(p, KTR_SYSCALL)) {
@@ -1124,13 +1118,10 @@ syscall(frame)
 	p->p_retval[0] = 0;
 	p->p_retval[1] = frame.tf_edx;
 
-	STOPEVENT(p, S_SCE, narg);	/* MP aware */
+	STOPEVENT(p, S_SCE, narg);
 
 	error = (*callp->sy_call)(p, args);
 
-	/*
-	 * MP SAFE (we may or may not have the MP lock at this point)
-	 */
 	switch (error) {
 	case 0:
 		frame.tf_eax = p->p_retval[0];
@@ -1163,7 +1154,7 @@ bad:
 	}
 
 	/*
-	 * Traced syscall.  trapsignal() is not MP aware.
+	 * Traced syscall.
 	 */
 	if ((frame.tf_eflags & PSL_T) && !(frame.tf_eflags & PSL_VM)) {
 		if (!mtx_owned(&Giant))