target/arm/translate-a64: Don't underdecode system instructions

The "system instructions" and "system register move" subcategories
of "branches, exception generating and system instructions" for A64
only apply if bits [23:22] are zero; other values are currently
unallocated. Correctly UNDEF these unallocated encodings.

Reported-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Message-id: 20190125182626.9221-2-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2019-02-01 14:55:44 +00:00
parent 23f9242332
commit 08d5e3bde6

View file

@ -2144,7 +2144,11 @@ static void disas_b_exc_sys(DisasContext *s, uint32_t insn)
break;
case 0x6a: /* Exception generation / System */
if (insn & (1 << 24)) {
disas_system(s, insn);
if (extract32(insn, 22, 2) == 0) {
disas_system(s, insn);
} else {
unallocated_encoding(s);
}
} else {
disas_exc(s, insn);
}