From 37769d27270eff15d878a1c7df23407fc5f09b7f Mon Sep 17 00:00:00 2001
From: Aurelien Jarno <aurelien@aurel32.net>
Date: Sat, 7 Jan 2012 15:20:12 +0100
Subject: [PATCH 19/25] target-sh4: ignore ocbp and ocbwb instructions

ocbp and ocbwb controls the writeback of a cache line to memory. They
are supposed to do nothing in case of a cache miss. Given QEMU only
partially emulate caches, it is safe to ignore these instructions.

This fixes a kernel oops when trying to access an rtl8139 NIC with
recent versions.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
(cherry picked from commit 0cdb95549fedc73e13c147ab9dcabcc303426a07)
---
 target-sh4/translate.c |   14 +++-----------
 1 files changed, 3 insertions(+), 11 deletions(-)

diff --git a/target-sh4/translate.c b/target-sh4/translate.c
index bad3577..e04a6e0 100644
--- a/target-sh4/translate.c
+++ b/target-sh4/translate.c
@@ -1652,18 +1652,10 @@ static void _decode_opc(DisasContext * ctx)
 	}
 	return;
     case 0x00a3:		/* ocbp @Rn */
-	{
-	    TCGv dummy = tcg_temp_new();
-	    tcg_gen_qemu_ld32s(dummy, REG(B11_8), ctx->memidx);
-	    tcg_temp_free(dummy);
-	}
-	return;
     case 0x00b3:		/* ocbwb @Rn */
-	{
-	    TCGv dummy = tcg_temp_new();
-	    tcg_gen_qemu_ld32s(dummy, REG(B11_8), ctx->memidx);
-	    tcg_temp_free(dummy);
-	}
+        /* These instructions are supposed to do nothing in case of
+           a cache miss. Given that we only partially emulate caches
+           it is safe to simply ignore them. */
 	return;
     case 0x0083:		/* pref @Rn */
 	return;
-- 
1.7.7.5