diff --git a/common/lib/libc/arch/mips/atomic/atomic_add.S b/common/lib/libc/arch/mips/atomic/atomic_add.S
index 886b6d54cf1b..1eac9a3c9c1e 100644
--- a/common/lib/libc/arch/mips/atomic/atomic_add.S
+++ b/common/lib/libc/arch/mips/atomic/atomic_add.S
@@ -49,6 +49,7 @@ LEAF(_atomic_add_32)
 #if defined(_MIPS_ARCH_OCTEONP) || defined(_MIPS_ARCH_OCTEON2)
 	saa		a1, (a0)
 #else
+	LLSCSYNC
 1:	INT_LL		t0, 0(a0)
 	 nop
 	INT_ADDU	t0, a1
@@ -62,6 +63,7 @@ END(_atomic_add_32)
 ATOMIC_OP_ALIAS(atomic_add_32, _atomic_add_32)
 
 LEAF(_atomic_add_32_nv)
+	LLSCSYNC
 1:	INT_LL		v0, 0(a0)
 	 nop
 	INT_ADDU	v0, a1
@@ -79,6 +81,7 @@ LEAF(_atomic_add_64)
 #if defined(_MIPS_ARCH_OCTEONP) || defined(_MIPS_ARCH_OCTEON2)
 	saad		a1, (a0)
 #else
+	LLSCSYNC
 1:	REG_LL		t0, 0(a0)
 	 nop
 	REG_ADDU	t0, a1
@@ -92,6 +95,7 @@ END(_atomic_add_64)
 ATOMIC_OP_ALIAS(atomic_add_64, _atomic_add_64)
 
 LEAF(_atomic_add_64_nv)
+	LLSCSYNC
 1:	REG_LL		v0, 0(a0)
 	 nop
 	REG_ADDU	v0, a1
diff --git a/common/lib/libc/arch/mips/atomic/atomic_and.S b/common/lib/libc/arch/mips/atomic/atomic_and.S
index cb1eb4848b23..e707f5f37cca 100644
--- a/common/lib/libc/arch/mips/atomic/atomic_and.S
+++ b/common/lib/libc/arch/mips/atomic/atomic_and.S
@@ -46,6 +46,7 @@ RCSID("$NetBSD: atomic_and.S,v 1.4 2012/03/14 16:50:34 christos Exp $")
 
 
 LEAF(_atomic_and_32)
+	LLSCSYNC
 1:	INT_LL		t0, 0(a0)
 	 nop
 	and		t0, a1
@@ -58,6 +59,7 @@ END(_atomic_and_32)
 ATOMIC_OP_ALIAS(atomic_and_32, _atomic_and_32)
 
 LEAF(_atomic_and_32_nv)
+	LLSCSYNC
 1:	INT_LL		v0, 0(a0)
 	 nop
 	and		v0, a1
@@ -72,6 +74,7 @@ ATOMIC_OP_ALIAS(atomic_and_32_nv, _atomic_and_32_nv)
 
 #if !defined(__mips_o32)
 LEAF(_atomic_and_64)
+	LLSCSYNC
 1:	REG_LL		t0, 0(a0)
 	 nop
 	and		t0, a1
@@ -84,6 +87,7 @@ END(_atomic_and_64)
 ATOMIC_OP_ALIAS(atomic_and_64, _atomic_and_64)
 
 LEAF(_atomic_and_64_nv)
+	LLSCSYNC
 1:	REG_LL		v0, 0(a0)
 	 nop
 	and		v0, a1
diff --git a/common/lib/libc/arch/mips/atomic/atomic_cas.S b/common/lib/libc/arch/mips/atomic/atomic_cas.S
index 5afcae13e48c..416d00e72907 100644
--- a/common/lib/libc/arch/mips/atomic/atomic_cas.S
+++ b/common/lib/libc/arch/mips/atomic/atomic_cas.S
@@ -37,6 +37,7 @@ RCSID("$NetBSD: atomic_cas.S,v 1.6 2019/02/20 05:25:12 rin Exp $")
 	.set	nomacro
 
 LEAF(_atomic_cas_32)
+	LLSCSYNC
 1:	INT_LL		v0, 0(a0)
 	 nop
 	bne		v0, a1, 2f
@@ -58,6 +59,7 @@ ATOMIC_OP_ALIAS(atomic_cas_32_ni, _atomic_cas_32)
 
 #if !defined(__mips_o32)
 LEAF(_atomic_cas_64)
+	LLSCSYNC
 1:	REG_LL		v0, 0(a0)
 	 nop
 	bne		v0, a1, 2f
diff --git a/common/lib/libc/arch/mips/atomic/atomic_dec.S b/common/lib/libc/arch/mips/atomic/atomic_dec.S
index 641ad9b3c73d..0dadebfc6d37 100644
--- a/common/lib/libc/arch/mips/atomic/atomic_dec.S
+++ b/common/lib/libc/arch/mips/atomic/atomic_dec.S
@@ -49,6 +49,7 @@ LEAF(_atomic_dec_32)
 	li		t0, -1
 	saa		t0, (a0)
 #else
+	LLSCSYNC
 1:	INT_LL		t0, 0(a0)
 	 nop
 	INT_ADDU	t0, -1
@@ -62,6 +63,7 @@ END(_atomic_dec_32)
 ATOMIC_OP_ALIAS(atomic_dec_32, _atomic_dec_32)
 
 LEAF(_atomic_dec_32_nv)
+	LLSCSYNC
 1:	INT_LL		v0, 0(a0)
 	 nop
 	INT_ADDU	v0, -1
@@ -80,6 +82,7 @@ LEAF(_atomic_dec_64)
 	li		t0, -1
 	saad		t0, (a0)
 #else
+	LLSCSYNC
 1:	REG_LL		t0, 0(a0)
 	 nop
 	REG_ADDU	t0, -1
@@ -93,6 +96,7 @@ END(_atomic_dec_64)
 ATOMIC_OP_ALIAS(atomic_dec_64, _atomic_dec_64)
 
 LEAF(_atomic_dec_64_nv)
+	LLSCSYNC
 1:	REG_LL		v0, 0(a0)
 	 nop
 	REG_ADDU	v0, -1
diff --git a/common/lib/libc/arch/mips/atomic/atomic_inc.S b/common/lib/libc/arch/mips/atomic/atomic_inc.S
index 40fadb8c45d1..6ef59d8c37bd 100644
--- a/common/lib/libc/arch/mips/atomic/atomic_inc.S
+++ b/common/lib/libc/arch/mips/atomic/atomic_inc.S
@@ -50,6 +50,7 @@ LEAF(_atomic_inc_32)
 	li		t0, 1
 	saa		t0, (a0)
 #else
+	LLSCSYNC
 1:	INT_LL		t0, 0(a0)
 	 nop
 	INT_ADDU	t0, 1
@@ -63,6 +64,7 @@ END(_atomic_inc_32)
 ATOMIC_OP_ALIAS(atomic_inc_32, _atomic_inc_32)
 
 LEAF(_atomic_inc_32_nv)
+	LLSCSYNC
 1:	INT_LL		v0, 0(a0)
 	 nop
 	INT_ADDU	v0, 1
@@ -81,6 +83,7 @@ LEAF(_atomic_inc_64)
 	li		t0, 1
 	saad		t0, (a0)
 #else
+	LLSCSYNC
 1:	REG_LL		t0, 0(a0)
 	 nop
 	REG_ADDU	t0, 1
@@ -94,6 +97,7 @@ END(_atomic_inc_64)
 ATOMIC_OP_ALIAS(atomic_inc_64, _atomic_inc_64)
 
 LEAF(_atomic_inc_64_nv)
+	LLSCSYNC
 1:	REG_LL		v0, 0(a0)
 	 nop
 	REG_ADDU	v0, 1
diff --git a/common/lib/libc/arch/mips/atomic/atomic_or.S b/common/lib/libc/arch/mips/atomic/atomic_or.S
index 595bc4ec7ce9..f891c71f3931 100644
--- a/common/lib/libc/arch/mips/atomic/atomic_or.S
+++ b/common/lib/libc/arch/mips/atomic/atomic_or.S
@@ -43,6 +43,7 @@
 #endif /* _KERNEL_OPT */
 
 LEAF(_atomic_or_32)
+	LLSCSYNC
 1:	INT_LL		t0, 0(a0)
 	 nop
 	or		t0, a1
@@ -55,6 +56,7 @@ END(_atomic_or_32)
 ATOMIC_OP_ALIAS(atomic_or_32, _atomic_or_32)
 
 LEAF(_atomic_or_32_nv)
+	LLSCSYNC
 1:	INT_LL		v0, 0(a0)
 	 nop
 	or		v0, a1
@@ -69,6 +71,7 @@ ATOMIC_OP_ALIAS(atomic_or_32_nv, _atomic_or_32_nv)
 
 #if !defined(__mips_o32)
 LEAF(_atomic_or_64)
+	LLSCSYNC
 1:	REG_LL		t0, 0(a0)
 	 nop
 	or		t0, a1
@@ -81,6 +84,7 @@ END(_atomic_or_64)
 ATOMIC_OP_ALIAS(atomic_or_64, _atomic_or_64)
 
 LEAF(_atomic_or_64_nv)
+	LLSCSYNC
 1:	REG_LL		v0, 0(a0)
 	 nop
 	or		v0, a1
diff --git a/common/lib/libc/arch/mips/atomic/atomic_swap.S b/common/lib/libc/arch/mips/atomic/atomic_swap.S
index 591665ff67ad..45a2782e85f4 100644
--- a/common/lib/libc/arch/mips/atomic/atomic_swap.S
+++ b/common/lib/libc/arch/mips/atomic/atomic_swap.S
@@ -44,8 +44,8 @@ RCSID("$NetBSD: atomic_swap.S,v 1.5 2015/06/01 23:16:54 matt Exp $")
 	.set	nomacro
 #endif /* _KERNEL_OPT */
 
-
 LEAF(_atomic_swap_32)
+	LLSCSYNC
 1:	INT_LL		v0, 0(a0)
 	 nop
 	move		t0, a1
@@ -60,6 +60,7 @@ ATOMIC_OP_ALIAS(atomic_swap_32, _atomic_swap_32)
 
 #if !defined(__mips_o32)
 LEAF(_atomic_swap_64)
+	LLSCSYNC
 1:	REG_LL		v0, 0(a0)
 	 nop
 	move		t0, a1
diff --git a/sys/arch/evbmips/conf/OCTEON.MP b/sys/arch/evbmips/conf/OCTEON.MP
index e5c24923ac56..33da849771ae 100644
--- a/sys/arch/evbmips/conf/OCTEON.MP
+++ b/sys/arch/evbmips/conf/OCTEON.MP
@@ -2,8 +2,8 @@
 
 include		"arch/evbmips/conf/OCTEON"
 
-options 	LOCKDEBUG
+#options 	LOCKDEBUG
 options 	DEBUG		# extra kernel debugging support
-
+options 	UVMHIST
 
 options 	MULTIPROCESSOR
diff --git a/sys/arch/mips/include/asm.h b/sys/arch/mips/include/asm.h
index c0bdfc5a8b50..53fe45639486 100644
--- a/sys/arch/mips/include/asm.h
+++ b/sys/arch/mips/include/asm.h
@@ -54,6 +54,10 @@
 #ifndef _MIPS_ASM_H
 #define	_MIPS_ASM_H
 
+#include "opt_cputype.h"
+#include "opt_lockdebug.h"
+#include "opt_multiprocessor.h"
+
 #include <sys/cdefs.h>		/* for API selection */
 #include <mips/regdef.h>
 
@@ -513,6 +517,23 @@ _C_LABEL(x):
 #define	NOP_L		/* nothing */
 #endif
 
+#if defined(MULTIPROCESSOR)
+#if defined(MIPS64_OCTEON)
+#define	LLSCSYNC	sync 4; sync 4
+#define	SYNC		sync 4		/* aka syncw */
+#define	BDSYNC		sync 4		/* aka syncw */
+#else
+#define	LLSCSYNC	/* nothing (something?) */
+#define	SYNC		sync
+#define	BDSYNC		sync
+#endif
+#else
+#define	LLSCSYNC	/* nothing */
+#define	SYNC		/* nothing */
+#define	BDSYNC		nop
+#endif /* defined(MULTIPROCESSOR) */
+
+
 /* CPU dependent hook for cp0 load delays */
 #if defined(MIPS1) || defined(MIPS2) || defined(MIPS3)
 #define	MFC0_HAZARD	sll $0,$0,1	/* super scalar nop */
diff --git a/sys/arch/mips/mips/db_disasm.c b/sys/arch/mips/mips/db_disasm.c
index cfee99054377..2ca7910d9a4b 100644
--- a/sys/arch/mips/mips/db_disasm.c
+++ b/sys/arch/mips/mips/db_disasm.c
@@ -59,7 +59,7 @@ static const char * const op_name[64] = {
 /*24 */ "daddi","daddiu","ldl", "ldr",	"op34", "op35", "op36", "op37",
 /*32 */ "lb",	"lh",	"lwl",	"lw",	"lbu",	"lhu",	"lwr",	"lwu",
 /*40 */ "sb",	"sh",	"swl",	"sw",	"sdl",	"sdr",	"swr",	"cache",
-#ifdef __OCTEON__
+#ifdef MIPS64_OCTEON
 /*48 */ "ll",	"lwc1", "bbit0", "lwc3", "lld",	"ldc1", "bbit032", "ld",
 /*56 */ "sc",	"swc1", "bbit1", "swc3", "scd",	"sdc1", "bbit132", "sd"
 #else
@@ -83,7 +83,7 @@ static const char * const spec2_name[64] = {	/* QED RM4650, R5000, etc. */
 	[OP_MADD] = "madd",
 	[OP_MADDU] = "maddu",
 	[OP_MUL] = "mul",
-#ifdef __OCTEON__
+#ifdef MIPS64_OCTEON
 	[OP_CVM_DMUL] = "baddu",
 #endif
 	[OP_MSUB] = "msub",
@@ -92,7 +92,7 @@ static const char * const spec2_name[64] = {	/* QED RM4650, R5000, etc. */
 	[OP_CLO] = "clo",
 	[OP_DCLZ] = "dclz",
 	[OP_DCLO] = "dclo",
-#ifdef __OCTEON__
+#ifdef MIPS64_OCTEON
 	[OP_CVM_BADDU] = "baddu",
 	[OP_CVM_POP] = "pop",
 	[OP_CVM_DPOP] = "dpop",
@@ -377,7 +377,7 @@ db_disasm_insn(int insn, db_addr_t loc, bool altfmt)
 			break;
 		}
 		if (i.RType.func == OP_MUL
-#ifdef __OCTEON__
+#ifdef MIPS64_OCTEON
 		    || i.RType.func == OP_CVM_DMUL
 		    || i.RType.func == OP_CVM_SEQ
 		    || i.RType.func == OP_CVM_SNE
@@ -390,7 +390,7 @@ db_disasm_insn(int insn, db_addr_t loc, bool altfmt)
 		    		reg_name[i.RType.rt]);
 			break;
 		}
-#ifdef __OCTEON__
+#ifdef MIPS64_OCTEON
 		if (i.RType.func == OP_CVM_CINS
 		    || i.RType.func == OP_CVM_CINS32
 		    || i.RType.func == OP_CVM_EXTS
@@ -423,7 +423,7 @@ db_disasm_insn(int insn, db_addr_t loc, bool altfmt)
 #endif
 		if (i.RType.func == OP_CLO
 		    || i.RType.func == OP_DCLO
-#ifdef __OCTEON__
+#ifdef MIPS64_OCTEON
 		    || i.RType.func == OP_CVM_POP
 		    || i.RType.func == OP_CVM_DPOP
 #endif
@@ -735,7 +735,7 @@ db_disasm_insn(int insn, db_addr_t loc, bool altfmt)
 		bdslot = true;
 		break;
 
-#ifdef __OCTEON__
+#ifdef MIPS64_OCTEON
 	case OP_CVM_BBIT0:
 	case OP_CVM_BBIT032:
 	case OP_CVM_BBIT1:
diff --git a/sys/arch/mips/mips/lock_stubs_llsc.S b/sys/arch/mips/mips/lock_stubs_llsc.S
index 12c99b01be0f..6704df7ef65f 100644
--- a/sys/arch/mips/mips/lock_stubs_llsc.S
+++ b/sys/arch/mips/mips/lock_stubs_llsc.S
@@ -46,14 +46,17 @@ RCSID("$NetBSD: lock_stubs_llsc.S,v 1.9 2019/04/06 03:06:26 thorpej Exp $")
 #endif
 
 #if defined(MULTIPROCESSOR)
-#if defined(__OCTEON__)
-#define	SYNC		sync 4
-#define	BDSYNC		sync 4
+#if defined(MIPS64_OCTEON)
+#define	LLSCSYNC	sync 4; sync 4
+#define	SYNC		sync 4		/* aka syncw */
+#define	BDSYNC		sync 4		/* aka syncw */
 #else
+#define	LLSCSYNC	/* nothing (something?) */
 #define	SYNC		sync
 #define	BDSYNC		sync
 #endif
 #else
+#define	LLSCSYNC	/* nothing */
 #define	SYNC		/* nothing */
 #define	BDSYNC		nop
 #endif /* defined(MULTIPROCESSOR) */
@@ -84,6 +87,7 @@ RCSID("$NetBSD: lock_stubs_llsc.S,v 1.9 2019/04/06 03:06:26 thorpej Exp $")
  *     unsigned long old, unsigned long new);
  */
 STATIC_LEAF(llsc_atomic_cas_ulong)
+	LLSCSYNC
 1:
 	LONG_LL	t0, (a0)
 	bne	t0, a1, 2f
@@ -104,6 +108,7 @@ END(llsc_atomic_cas_ulong)
  *    unsigned int old, unsigned int new);
  */
 STATIC_LEAF(llsc_atomic_cas_uint)
+	LLSCSYNC
 1:
 	INT_LL	t0, (a0)
 	bne	t0, a1, 2f
@@ -133,6 +138,7 @@ STATIC_LEAF(llsc_ucas_32)
 	 nop
 	move	v0, zero
 
+	LLSCSYNC
 1:	ll	t0, 0(a0)
 	bne	t0, a1, 2f
 	 move	t1, a2
@@ -161,6 +167,7 @@ STATIC_LEAF(llsc_ucas_64)
 	 nop
 	move	v0, zero
 
+	LLSCSYNC
 1:	lld	t0, 0(a0)
 	bne	t0, a1, 2f
 	 move	t1, a2
@@ -187,6 +194,7 @@ END(llsc_ucaserr)
  * void	mutex_enter(kmutex_t *mtx);
  */
 STATIC_LEAF(llsc_mutex_enter)
+	LLSCSYNC
 	PTR_LL	t0, MTX_OWNER(a0)
 1:
 	bnez	t0, 2f
@@ -205,6 +213,7 @@ END(llsc_mutex_enter)
  * void	mutex_exit(kmutex_t *mtx);
  */
 STATIC_LEAF(llsc_mutex_exit)
+	LLSCSYNC
 	PTR_LL	t0, MTX_OWNER(a0)
 	SYNC
 1:
@@ -268,6 +277,7 @@ STATIC_NESTED(llsc_mutex_spin_enter, CALLFRAME_SIZ, ra)
 	 nop
 #endif /* PARANOIA */
 #if defined(FULL)
+	LLSCSYNC
 	INT_LL	t3, MTX_LOCK(t0)
 3:
 	bnez	t3, 4f