target/arm: Don't corrupt insn_start arguments on 32-bit hostsicount-debug

For the Arm target, we have a 3-operand tcg_insn_start,
where the 3 arguments are the PC, condexec bits, and
a syndrome value. We set it up like this:

    tcg_gen_insn_start(dc->pc,
                       (dc->condexec_cond << 4) | (dc->condexec_mask >> 1),
                       0);
    dc->insn_start = tcg_last_op();

and then we patch in the 3rd operand later in disas_set_insn_syndrome():
    tcg_set_insn_param(s->insn_start, 2, syn);

Unfortunately, if we're running on a setup where
TARGET_LONG_BITS > TCG_TARGET_REG_BITS (ie 64 bit guest
on 32 bit host), tcg_gen_insn_start() has under the hood
split the 3 operands we gave it into 6, and so we end
up patching a syndrome value into the condexec bits.
This means we'll end up with corrupted guest condexec
state if we have to do a cpu_restore_state(), which happens
often when using icount and occasionally for load/store
instructions that fault.

Fix the bug by using the correct operand offset for the
64-on-32 case.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

0 files changed, 0 insertions, 0 deletions