ARCv2: entry: early return from exception need not clear U & DE bits

Exception handlers call FAKE_RET_FROM_EXCPN to - clear AE bit: drop down from exception active to pure kernel mode allowing further excptions - set IE bit: re-enable interrupts It additionally also clears U bit (user mode) and DE bit (delay slot execution) which is redundant as hardware does that already on any taken exception. Morevoer the current software clearing is bogus anyways as the KFLAG instruction being used for purpose can't possibly write those bits anyways. So don't pretend to clear them. Signed-off-by: Alexey Brodkin <[email protected]> Signed-off-by: Vineet Gupta <[email protected]> [vgupta: rewrote changelog]
josf · Aug 5, 2019 · 97abfd5 · 97abfd5
1 parent 5f9e832
commit 97abfd5
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/arch/arc/include/asm/entry-arcv2.h b/arch/arc/include/asm/entry-arcv2.h
@@ -256,7 +256,7 @@
 
 .macro FAKE_RET_FROM_EXCPN
 	lr      r9, [status32]
-	bic     r9, r9, (STATUS_U_MASK|STATUS_DE_MASK|STATUS_AE_MASK)
+	bic     r9, r9, STATUS_AE_MASK
 	or      r9, r9, STATUS_IE_MASK
 	kflag   r9
 .endm