FAKE_RET_FROM_EXCEPTION drops down to pure kernel mode. It currently has
an 8 byte instruction which can be replaced with 4 byte BSET
This is applicable to both ARCv2 and ARCv3 entr code.
ARCv2 current
------------
00000804 <EV_Trap>:
...
874: 216a 1280 lr r9,[status32]
878: 2146 1809 bic r9,r9,0x20
87c: 2105 1f89 8000 0000 or r9,r9,0x80000000
^^^^^^^^^
884: 2029 8240 kflag r9
ARCv2 after
----------
000007e0 <EV_Trap>:
...
850: 216a 1280 lr r9,[status32]
854: 2150 1149 bclr r9,r9,0x5
858: 214f 17c9 bset r9,r9,0x1f
85c: 2029 8240 kflag r9
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
.macro FAKE_RET_FROM_EXCPN
lr r9, [status32]
- bic r9, r9, STATUS_AE_MASK
- or r9, r9, STATUS_IE_MASK
+ bclr r9, r9, STATUS_AE_BIT
+ bset r9, r9, STATUS_IE_BIT
kflag r9
.endm