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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>
This commit is contained in:
Aurelien Jarno 2012-01-07 15:20:12 +01:00
parent 05b922dd0a
commit 0cdb95549f
1 changed files with 3 additions and 11 deletions
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14
target-sh4/translate.c
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@ -1652,18 +1652,10 @@ static void _decode_opc(DisasContext * ctx)
} }
return; return;
case 0x00a3: /* ocbp @Rn */ 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 */ case 0x00b3: /* ocbwb @Rn */
{ /* These instructions are supposed to do nothing in case of
TCGv dummy = tcg_temp_new(); a cache miss. Given that we only partially emulate caches
tcg_gen_qemu_ld32s(dummy, REG(B11_8), ctx->memidx); it is safe to simply ignore them. */
tcg_temp_free(dummy);
}
return; return;
case 0x0083: /* pref @Rn */ case 0x0083: /* pref @Rn */
return; return;