arch: arc: fix the bug of IRQ_ACT.U bit sync up

This bug is brought in commit 3f88ddd54999.

The cleanup of IRQ_ACT.U bit before thread switch is not done.

The bug comes out at the case where interrupt comes in user mode,
then a thread switch happens, and the target thread is to run in kernel
mode. Because the U bit is not sync up correctly, the stack operation
is wrong.

Signed-off-by: Wayne Ren <wei.ren@synopsys.com>

arch/arc/include/swap_macros.h

@@ -407,12 +407,21 @@
 .macro _irq_store_old_thread_callee_regs
 #if defined(CONFIG_USERSPACE)
 /*
+ * when USERSPACE is enabled, according to ARCv2 ISA, SP will be switched
+ * if interrupt comes out in user mode, and will be recorded in bit 31
+ * (U bit) of IRQ_ACT. when interrupt exits, SP will be switched back
+ * according to U bit.
+ *
  * need to remember the user/kernel status of interrupted thread, will be
  * restored when thread switched back
+ *
  */
-	lr r3, [_ARC_V2_AUX_IRQ_ACT]
-	and r3, r3, 0x80000000
+	lr r1, [_ARC_V2_AUX_IRQ_ACT]
+	and r3, r1, 0x80000000
 	push_s r3
+
+	bclr r1, r1, 31
+	sr r1, [_ARC_V2_AUX_IRQ_ACT]
 #endif
 	_store_old_thread_callee_regs
 .endm
@@ -440,22 +449,6 @@
 
 /* when switch to thread caused by coop, some status regs need to set */
 .macro _set_misc_regs_irq_switch_from_coop
-#if defined(CONFIG_USERSPACE)
-/*
- * when USERSPACE is enabled, according to ARCv2 ISA, SP will be switched
- * if interrupt comes out in user mode, and will be recorded in bit 31
- * (U bit) of IRQ_ACT. when interrupt exits, SP will be switched back
- * according to U bit.
- *
- * For the case that context switches in interrupt, the target sp must be
- * thread's kernel stack, no need to do hardware sp switch. so, U bit should
- * be cleared.
- */
-	lr r0, [_ARC_V2_AUX_IRQ_ACT]
-	bclr r0, r0, 31
-	sr r0, [_ARC_V2_AUX_IRQ_ACT]
-#endif
-
 #ifdef CONFIG_ARC_SECURE_FIRMWARE
 	/* must return to secure mode, so set IRM bit to 1 */
 	lr r0, [_ARC_V2_SEC_STAT]