On 12/11/18 9:40 AM, Peter Maydell wrote:
> On Fri, 7 Dec 2018 at 10:36, Richard Henderson
> <richard.hender...@linaro.org> wrote:
>>
>> This will enable PAuth decode in a subsequent patch.
>>
>> Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
>> ---
>> target/arm/translate-a64.c | 34 +++++++++++++++++++++++-----------
>> 1 file changed, 23 insertions(+), 11 deletions(-)
>>
>> diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
>> index c84c2dbb66..5fa2647771 100644
>> --- a/target/arm/translate-a64.c
>> +++ b/target/arm/translate-a64.c
>> @@ -1989,32 +1989,41 @@ static void disas_uncond_b_reg(DisasContext *s,
>> uint32_t insn)
>> rn = extract32(insn, 5, 5);
>> op4 = extract32(insn, 0, 5);
>>
>> - if (op4 != 0x0 || op3 != 0x0 || op2 != 0x1f) {
>> - unallocated_encoding(s);
>> - return;
>> + if (op2 != 0x1f) {
>> + goto do_unallocated;
>> }
>>
>> switch (opc) {
>> case 0: /* BR */
>> case 1: /* BLR */
>> case 2: /* RET */
>> - gen_a64_set_pc(s, cpu_reg(s, rn));
>> + if (op3 == 0 && op4 == 0) {
>> + dst = cpu_reg(s, rn);
>> + } else {
>> + goto do_unallocated;
>> + }
>> + gen_a64_set_pc(s, dst);
>> /* BLR also needs to load return address */
>> if (opc == 1) {
>> tcg_gen_movi_i64(cpu_reg(s, 30), s->pc);
>> }
>> break;
>> +
>> case 4: /* ERET */
>> if (s->current_el == 0) {
>> - unallocated_encoding(s);
>> - return;
>> - }
>> - if (tb_cflags(s->base.tb) & CF_USE_ICOUNT) {
>> - gen_io_start();
>> + goto do_unallocated;
>> }
>> dst = tcg_temp_new_i64();
>> tcg_gen_ld_i64(dst, cpu_env,
>> offsetof(CPUARMState, elr_el[s->current_el]));
>> + if (op3 == 0 && op4 == 0) {
>> + ;
>> + } else {
>> + goto do_unallocated;
>
>
> This decode check should go before any code has been
> emittede (ie before the tcg_gen_ld_i64 above it).
Well, it could, but only if we duplicate the ld_i64 in the various branches
that require it. E.g.
if (op3 == 0 && op4 == 0) {
tcg_gen_ld_i64(...);
} else if (dc_ir_feature(aa64_pauth, s) && ...) {
tcg_gen_ld_i64(...);
if (s->pauth_active) {
gen_helper_auti*(...);
}
} else {
goto do_unallocated;
}
which I suppose isn't so bad.
What I have isn't an error because the ld_i64 will simply be deleted as dead
code by the tcg optimizer. But I'll rearrange anyway.
r~
