diff --git a/arch/x86/core/intel64/locore.S b/arch/x86/core/intel64/locore.S
index c685c4347bb..c0c0cab393d 100644
--- a/arch/x86/core/intel64/locore.S
+++ b/arch/x86/core/intel64/locore.S
@@ -175,7 +175,7 @@ __swap:
 	movq $_kernel, %rsi
 	movq _kernel_offset_to_current(%rsi), %rsi
 
-	orb $_THREAD_SWAPPED, _thread_offset_to_thread_state(%rsi)
+	andb $~X86_THREAD_FLAG_ALL, _thread_offset_to_flags(%rsi)
 
 	movl _k_neg_eagain, %eax
 	movl %eax, _thread_offset_to_rax(%rsi)
@@ -219,8 +219,8 @@ __resume:
 	movq _thread_offset_to_r15(%rsi), %r15
 	movq _thread_offset_to_rax(%rsi), %rax
 
-	testb $_THREAD_SWAPPED, _thread_offset_to_thread_state(%rsi)
-	jnz 1f
+	testb $X86_THREAD_FLAG_ALL, _thread_offset_to_flags(%rsi)
+	jz 1f
 
 	fxrstor _thread_offset_to_sse(%rsi)
 	movq _thread_offset_to_rcx(%rsi), %rcx
@@ -466,7 +466,7 @@ irq_enter_nested: /* Nested IRQ: dump register state to stack. */
 
 irq_enter_unnested: /* Not nested: dump state to thread struct for __resume */
 	movq _kernel_offset_to_current(%rsi), %rsi
-	andb $(~_THREAD_SWAPPED), _thread_offset_to_thread_state(%rsi)
+	orb $X86_THREAD_FLAG_ALL, _thread_offset_to_flags(%rsi)
 	fxsave _thread_offset_to_sse(%rsi)
 	movq %rbx, _thread_offset_to_rbx(%rsi)
 	movq %rbp, _thread_offset_to_rbp(%rsi)
diff --git a/arch/x86/core/intel64/thread.c b/arch/x86/core/intel64/thread.c
index 9a222bb45b4..e84ecfbac4c 100644
--- a/arch/x86/core/intel64/thread.c
+++ b/arch/x86/core/intel64/thread.c
@@ -30,4 +30,6 @@ void z_new_thread(struct k_thread *thread, k_thread_stack_t *stack,
 	thread->arch.rcx = (long) parameter3;
 
 	x86_sse_init(thread);
+
+	thread->arch.flags = X86_THREAD_FLAG_ALL;
 }
diff --git a/arch/x86/core/offsets/intel64_offsets.c b/arch/x86/core/offsets/intel64_offsets.c
index 74d864d6fc4..81a25d711f0 100644
--- a/arch/x86/core/offsets/intel64_offsets.c
+++ b/arch/x86/core/offsets/intel64_offsets.c
@@ -18,6 +18,7 @@ GEN_OFFSET_SYM(_callee_saved_t, rip);
 GEN_OFFSET_SYM(_callee_saved_t, rflags);
 GEN_OFFSET_SYM(_callee_saved_t, rax);
 
+GEN_OFFSET_SYM(_thread_arch_t, flags);
 GEN_OFFSET_SYM(_thread_arch_t, rcx);
 GEN_OFFSET_SYM(_thread_arch_t, rdx);
 GEN_OFFSET_SYM(_thread_arch_t, rsi);
diff --git a/arch/x86/include/intel64/kernel_arch_data.h b/arch/x86/include/intel64/kernel_arch_data.h
index c551cd32cf3..18c6ae5ea5b 100644
--- a/arch/x86/include/intel64/kernel_arch_data.h
+++ b/arch/x86/include/intel64/kernel_arch_data.h
@@ -14,14 +14,6 @@
 #define X86_FXSAVE_ALIGN	16	/* ... for FXSAVE/FXRSTOR ops */
 #define X86_MXCSR_SANE		0x1dc0	/* enable division-by-zero exception */
 
-/*
- * A flag for k_thread.thread_state to tell __resume that the thread
- * voluntarily switched itself out, so only a portion of the register
- * state needs to be restored. See kernel_arch_thread.h and locore.S.
- */
-
-#define _THREAD_SWAPPED BIT(7)
-
 /*
  * GDT selectors - these must agree with the GDT layout in locore.S.
  */
diff --git a/arch/x86/include/intel64/kernel_arch_thread.h b/arch/x86/include/intel64/kernel_arch_thread.h
index 07d47a5faad..fae7d26716e 100644
--- a/arch/x86/include/intel64/kernel_arch_thread.h
+++ b/arch/x86/include/intel64/kernel_arch_thread.h
@@ -6,6 +6,8 @@
 #ifndef ZEPHYR_ARCH_X86_INCLUDE_INTEL64_KERNEL_ARCH_THREAD_H_
 #define ZEPHYR_ARCH_X86_INCLUDE_INTEL64_KERNEL_ARCH_THREAD_H_
 
+#define X86_THREAD_FLAG_ALL 0x01 /* _thread_arch.flags: entire state saved */
+
 #ifndef _ASMLANGUAGE
 
 #include <zephyr/types.h>
@@ -14,7 +16,7 @@
 /*
  * The _callee_saved registers are unconditionally saved/restored across
  * context switches; the _thread_arch registers are only preserved when
- * the thread is interrupted. _THREAD_SWAPPED tells __resume when it can
+ * the thread is interrupted. _arch_thread.flags tells __resume when to
  * cheat and only restore the first set. For more details see locore.S.
  */
 
@@ -34,6 +36,8 @@ struct _callee_saved {
 typedef struct _callee_saved _callee_saved_t;
 
 struct _thread_arch {
+	u8_t flags;
+
 	u64_t rcx;
 	u64_t rdx;
 	u64_t rsi;
diff --git a/arch/x86/include/intel64/offsets_short_arch.h b/arch/x86/include/intel64/offsets_short_arch.h
index 24b97c8ba37..5da0e111bf8 100644
--- a/arch/x86/include/intel64/offsets_short_arch.h
+++ b/arch/x86/include/intel64/offsets_short_arch.h
@@ -38,6 +38,9 @@
 #define _thread_offset_to_rax \
 	(___thread_t_callee_saved_OFFSET + ___callee_saved_t_rax_OFFSET)
 
+#define _thread_offset_to_flags \
+	(___thread_t_arch_OFFSET + ___thread_arch_t_flags_OFFSET)
+
 #define _thread_offset_to_rcx \
 	(___thread_t_arch_OFFSET + ___thread_arch_t_rcx_OFFSET)