arch: arc: set the right init status for user space

The fake exception return is used to jump to user mode.
So the init status of user thread is in exception mode.

Signed-off-by: Wayne Ren <[email protected]>

Author: Wayne Ren

arch/arc/core/thread.c

@@ -118,10 +118,14 @@ void _new_thread(struct k_thread *thread, k_thread_stack_t *stack,
 #if CONFIG_USERSPACE
 	if (options & K_USER) {
 		pInitCtx->pc = ((u32_t)_user_thread_entry_wrapper);
+		/* through exception return to user mode */
+		pInitCtx->status32 = _ARC_V2_STATUS32_AE;
 	} else {
+		pInitCtx->status32 = 0;
 		pInitCtx->pc = ((u32_t)_thread_entry_wrapper);
 	}
 #else
+	pInitCtx->status32 = 0;
 	pInitCtx->pc = ((u32_t)_thread_entry_wrapper);
 #endif
 
@@ -143,9 +147,9 @@ void _new_thread(struct k_thread *thread, k_thread_stack_t *stack,
 #ifdef CONFIG_ARC_STACK_CHECKING
 #ifdef CONFIG_ARC_HAS_SECURE
 	pInitCtx->sec_stat |= _ARC_V2_SEC_STAT_SSC;
-	pInitCtx->status32 = _ARC_V2_STATUS32_E(_ARC_V2_DEF_IRQ_LEVEL);
+	pInitCtx->status32 |= _ARC_V2_STATUS32_E(_ARC_V2_DEF_IRQ_LEVEL);
 #else
-	pInitCtx->status32 = _ARC_V2_STATUS32_SC |
+	pInitCtx->status32 |= _ARC_V2_STATUS32_SC |
 		 _ARC_V2_STATUS32_E(_ARC_V2_DEF_IRQ_LEVEL);
 #endif
 #ifdef CONFIG_USERSPACE
@@ -196,7 +200,7 @@ void _new_thread(struct k_thread *thread, k_thread_stack_t *stack,
 	 * dst[31:6] dst[5] dst[4]       dst[3:0]
 	 *    26'd0    1    STATUS32.IE  STATUS32.E[3:0]
 	 */
-	thread->arch.intlock_key = 0x3F;
+	thread->arch.intlock_key = 0x30 | (_ARC_V2_DEF_IRQ_LEVEL & 0xf);
 	thread->arch.relinquish_cause = _CAUSE_COOP;
 	thread->callee_saved.sp =
 		(u32_t)pInitCtx - ___callee_saved_stack_t_SIZEOF;

arch/arc/core/userspace.S

@@ -62,11 +62,6 @@ SECTION_FUNC(TEXT, _user_thread_entry_wrapper)
 	/* start of privilege stack */
 	add blink, r5, CONFIG_PRIVILEGED_STACK_SIZE+STACK_GUARD_SIZE+16
 
-	/* r4<- start  of user stack region */
-	mov r0, _kernel
-	ld_s r1, [r0, _kernel_offset_to_current]
-	ld r4, [r1, ___thread_stack_info_t_start_OFFSET]
-
 /*
  * when CONFIG_INIT_STACKS is enable, stack will be initialized
  * in _new_thread_init.
@@ -145,6 +140,7 @@ _clear_user_stack:
 _arc_go_to_user_space:
 	lr r0, [_ARC_V2_STATUS32]
 	bset r0, r0, _ARC_V2_STATUS32_U_BIT
+	bclr r0, r0, _ARC_V2_STATUS32_AE_BIT
 
 	mov r1, _thread_entry_wrapper