diff --git a/kernel/Makefile b/kernel/Makefile
index 7f0a316..0689fc6 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -8,7 +8,8 @@ SRCS	= kernel.asm \
 			klog.inc \
 			dev/vga_console.inc \
 			mm/mm.inc \
-			mm/pmm.inc
+			mm/pmm.inc \
+			lock.inc 
 
 .PHONY: all
 all: $(KERNEL)
diff --git a/kernel/isr.inc b/kernel/isr.inc
index 82c810e..e444ae5 100644
--- a/kernel/isr.inc
+++ b/kernel/isr.inc
@@ -1,13 +1,16 @@
-macro ISR_ERROR num {
-	cli
-
-	jmp isr_common
-}
-
-macro ISR_NOERROR num {
-	cli
-
-	jmp isr_common
+macro ISR [name,error] {
+isr_table:
+forward
+	dd isr_#name
+forward
+	isr_#name#:
+		cli
+		if error eq 0
+		push 0
+		end if
+		push error
+		jmp isr_common
+				 
 }
 
 isr_common:
@@ -32,3 +35,37 @@ isr_common:
 	add esp, 8
 	sti
 	iret
+
+ISR \
+	division_by_zero, 0, \
+	debug, 0, \
+	nmi, 0, \
+	breakpoint, 0, \
+	overflow, 0, \
+	bound_range_exceeded, 0, \
+	invalid_opcode, 0, \
+	device_not_available, 0, \
+	double_fault, 1, \
+	coproc_seg_overrun, 0, \
+	invalid_tss, 1, \
+	seg_not_present, 1, \
+	stack_seg_fault, 1, \
+	general_protection_fault, 1, \
+	page_fault, 1, \
+	reserved15, 0, \
+	x87_exception, 0, \
+	alignment_check, 0, \
+	machine_check, 0, \
+	simd_exception, 0, \
+	virt_exception, 0, \
+	reserved21, 0, \
+	reserved22, 0, \
+	reserved23, 0, \
+	reserved24, 0, \
+	reserved25, 0, \
+	reserved26, 0, \
+	reserved27, 0, \
+	reserved28, 0, \
+	reserved29, 0, \
+	security_exception, 0, \
+	reserved31, 0
diff --git a/kernel/kernel.asm b/kernel/kernel.asm
index 7b5d605..99690a9 100644
--- a/kernel/kernel.asm
+++ b/kernel/kernel.asm
@@ -68,6 +68,7 @@ kmain:
 	include 'klog.inc'
 	include 'dev/vga_console.inc'
 	include 'mm/mm.inc'
+	include 'lock.inc'
 
 szMsgKernelAlive db "Kernel is alive", 0
 szErrorBootProtocol db "Error: wrong magic number", 0
diff --git a/kernel/lock.inc b/kernel/lock.inc
index 5c632bb..fdd7b30 100644
--- a/kernel/lock.inc
+++ b/kernel/lock.inc
@@ -1,17 +1,13 @@
 
 	;; 
 lock_acquire:
-	lock bts [eax], 0
-	jnc .end
-@@:
-	pause
-	test [eax], 1
-	jne @b
-
-	lock bts [eax], 0
-	jc @b
-.end:
+	mov edx, 1	
+	xchg edx, [eax]
+	or edx, edx
+	jnz lock_acquire
 	ret
 
-release:
-	mov [eax], 0
+lock_release:
+	xor edx, edx
+	xchg [eax], edx
+	ret
diff --git a/kernel/mm/pmm.inc b/kernel/mm/pmm.inc
index b11a1fd..5111798 100644
--- a/kernel/mm/pmm.inc
+++ b/kernel/mm/pmm.inc
@@ -31,6 +31,10 @@ pmm_init:
 	;; Out:
 	;;    EAX - page address (return zero on error)
 pmm_alloc_page:
+	xchg bx, bx
+	mov eax, uPmmLock
+	call lock_acquire
+
 	cmp [pFreeList], 0
 	je .error
 	mov eax, [pFreeList]
@@ -40,11 +44,21 @@ pmm_alloc_page:
 	inc [cUsedPage]
 	dec [cFreePage]
 
+
+	push eax
+	mov eax, uPmmLock
+	call lock_release
+	pop eax
+
 	ret
 .error:
 	mov esi, szErrorNoMemLeft
 	call klog
+
+	mov eax, uPmmLock
+	call lock_release
 	xor eax, eax
+
 	ret
 
 	;; Function: pmm_free_page
@@ -53,6 +67,8 @@ pmm_alloc_page:
 	;; In:
 	;;    EAX - page to be freed
 pmm_free_page:
+	mov eax, uPmmLock
+	call lock_acquire
 	or eax, eax
 	jz @f
 	mov edx, [pFreeList]
@@ -62,6 +78,8 @@ pmm_free_page:
 	inc [cFreePage]
 	dec [cUsedPage]
 @@:
+	mov eax, uPmmLock
+	call lock_release
 	ret
 
 	;; Function: pmm_free_range
@@ -115,6 +133,7 @@ szMsgPmmInit      db "PMM: initialize", 0
 szMsgPmmFreeRange db "PMM: add free memory range %x - %x", 0
 szErrorNoMemLeft  db "Error: no free memory left", 0
 szMsgPmmStats     db "PMM: Total page: %x | Used page: %x | Free page: %x", 0
+uPmmLock          dd 0
 
 ; Some stats
 cFreePage  dd 0