ARC: [arcompact] entry.S: Improve early return from exception
The requirement is to
- Reenable Exceptions (AE cleared)
- Reenable Interrupts (E1/E2 set)
We need to do wiggle these bits into ERSTATUS and call RTIE.
Prev version used the pre-exception STATUS32 as starting point for what
goes into ERSTATUS. This required explicit fixups of U/DE/L bits.
Instead, use the current (in-exception) STATUS32 as starting point.
Being in exception handler U/DE/L can be safely assumed to be correct.
Only AE/E1/E2 need to be fixed.
So the new implementation is slightly better
-Avoids read form memory
-Is 4 bytes smaller for the typical 1 level of intr configuration
-Depicts the semantics more clearly
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
diff --git a/arch/arc/include/asm/entry-compact.h b/arch/arc/include/asm/entry-compact.h
index 415443c..1aff3be 100644
--- a/arch/arc/include/asm/entry-compact.h
+++ b/arch/arc/include/asm/entry-compact.h
@@ -110,13 +110,12 @@
.macro FAKE_RET_FROM_EXCPN
- ld r9, [sp, PT_status32]
- bic r9, r9, (STATUS_U_MASK|STATUS_DE_MASK)
- bset r9, r9, STATUS_L_BIT
- sr r9, [erstatus]
- mov r9, 55f
- sr r9, [eret]
-
+ lr r9, [status32]
+ bclr r9, r9, STATUS_AE_BIT
+ or r9, r9, (STATUS_E1_MASK|STATUS_E2_MASK)
+ sr r9, [erstatus]
+ mov r9, 55f
+ sr r9, [eret]
rtie
55:
.endm