From: Vineet Gupta <vgupta@synopsys.com>
Date: Sat, 6 Apr 2013 11:41:58 +0000 (+0530)
Subject: ARC: unaligned access emulation broken if callee-reg dest of LD/ST
X-Git-Tag: v3.10-rc1~25^2~16
X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=ce147c7445c28fcf38813f62b2a2bb1266db9ef4;p=~emulex%2Finfiniband.git

ARC: unaligned access emulation broken if callee-reg dest of LD/ST

The fixup code correctly updates the callee-regs on stack, but
fails to unwind it into actual register file. Thus userspace won't see
the update.

Reported-by: Noam Camus <noamc@ezchip.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---

diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S
index 666a486f1e7..0c6d664d4a8 100644
--- a/arch/arc/kernel/entry.S
+++ b/arch/arc/kernel/entry.S
@@ -396,7 +396,9 @@ ARC_ENTRY EV_TLBProtV
 
 	bl  do_misaligned_access
 
-	DISCARD_CALLEE_SAVED_USER
+	; TBD: optimize - do this only if a callee reg was involved
+	; either a dst of emulated LD/ST or src with address-writeback
+	RESTORE_CALLEE_SAVED_USER
 #else
 	bl  do_misaligned_error
 #endif