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 <aurel...@aurel32.net> --- 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 2ecb236..aacf96d 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; -- 1.7.7.3