On 10/20/18 8:14 AM, Bastian Koppelmann wrote:
> Signed-off-by: Bastian Koppelmann <[email protected]>
> Signed-off-by: Peer Adelt <[email protected]>
> ---
> v1 -> v2:
> - simplified fence/fence_i as suggested by Richard
>
> target/riscv/insn32.decode | 6 ++++++
> target/riscv/insn_trans/trans_rvi.inc.c | 20 ++++++++++++++++++++
> target/riscv/translate.c | 14 --------------
> 3 files changed, 26 insertions(+), 14 deletions(-)
>
> diff --git a/target/riscv/insn32.decode b/target/riscv/insn32.decode
> index cb7622e223..00e30dbc71 100644
> --- a/target/riscv/insn32.decode
> +++ b/target/riscv/insn32.decode
> @@ -24,6 +24,9 @@
> %sh6 20:6
> %sh5 20:5
>
> +%pred 24:4
> +%succ 20:4
Unused.
> +static bool trans_fence(DisasContext *ctx, arg_fence *a, uint32_t insn)
> +{
> +#ifndef CONFIG_USER_ONLY
> + /* FENCE is a full memory barrier. */
> + tcg_gen_mb(TCG_MO_ALL | TCG_BAR_SC);
> +#endif
> + return true;
> +}
> +static bool trans_fence_i(DisasContext *ctx, arg_fence_i *a, uint32_t insn)
Spacing.
> +{
> +#ifndef CONFIG_USER_ONLY
> + /* FENCE_I is a no-op in QEMU,
> + * however we need to end the translation block */
> + tcg_gen_movi_tl(cpu_pc, ctx->pc_succ_insn);
> + tcg_gen_exit_tb(NULL, 0);
> + ctx->base.is_jmp = DISAS_NORETURN;
> +#endif
> + return true;
> +}
I will note that both of these should apply to user-only as well...
> - case OPC_RISC_FENCE:
> -#ifndef CONFIG_USER_ONLY
> - if (ctx->opcode & 0x1000) {
> - /* FENCE_I is a no-op in QEMU,
> - * however we need to end the translation block */
> - tcg_gen_movi_tl(cpu_pc, ctx->pc_succ_insn);
> - tcg_gen_exit_tb(NULL, 0);
> - ctx->base.is_jmp = DISAS_NORETURN;
> - } else {
> - /* FENCE is a full memory barrier. */
> - tcg_gen_mb(TCG_MO_ALL | TCG_BAR_SC);
> - }
> -#endif
... even though you're simply copying the bug.
I mentioned this twice during initial review of risc-v, but it seems to have
been missed during commit.
Also note that one can do better than TCG_MO_ALL by actually using the
pred/succ bits to select TCG_MO_{LD,ST}_{LD,ST}.
That said, no new bugs with this patch, so
Reviewed-by: Richard Henderson <[email protected]>
r~
