On 04/07/2018 04:19 AM, Emilio G. Cota wrote:
> Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org>
> Cc: Aurelien Jarno <aurel...@aurel32.net>
> Cc: Yongbok Kim <yongbok....@mips.com>
> Signed-off-by: Emilio G. Cota <c...@braap.org>
> ---
> target/mips/translate.c | 186
> +++++++++++++++++++++++-------------------------
> 1 file changed, 91 insertions(+), 95 deletions(-)
>
> diff --git a/target/mips/translate.c b/target/mips/translate.c
> index d05ee67..a133205 100644
> --- a/target/mips/translate.c
> +++ b/target/mips/translate.c
> @@ -36,6 +36,7 @@
>
> #include "target/mips/trace.h"
> #include "trace-tcg.h"
> +#include "exec/translator.h"
> #include "exec/log.h"
>
> #define MIPS_DEBUG_DISAS 0
> @@ -1439,7 +1440,7 @@ typedef struct DisasContext {
> int mem_idx;
> TCGMemOp default_tcg_memop_mask;
> uint32_t hflags, saved_hflags;
> - int bstate;
> + DisasJumpType is_jmp;
> target_ulong btarget;
> bool ulri;
> int kscrexist;
> @@ -1460,13 +1461,8 @@ typedef struct DisasContext {
> bool abs2008;
> } DisasContext;
>
> -enum {
> - BS_NONE = 0, /* We go out of the TB without reaching a branch or an
> - * exception condition */
> - BS_STOP = 1, /* We want to stop translation for any reason */
> - BS_BRANCH = 2, /* We reached a branch condition */
> - BS_EXCP = 3, /* We reached an exception condition */
> -};
> +#define DISAS_STOP DISAS_TARGET_0
> +#define DISAS_EXCP DISAS_TARGET_1
Ok, well, there are existing bugs within the MIPS translation here, and we
might as well fix them within this patch set.
(1) The description for BS_STOP says we want to stop, but (what will become)
mips_tr_tb_stop calls goto_tb.
That's not correct, since we use that after e.g. helper_mtc0_hwrena,
MIPS_HFLAG_HWRENA_ULR is included in tb->flags, and therefore the next TB is
not fixed but depends on the actual value stored into hwrena.
We should instead use lookup_and_goto_ptr, which does a full lookup of the
processor state every time through.
(2) The BS_EXCP in generate_exception_err should map to DISAS_NORETURN, because
we do not return after raising an exception.
(3) Otherwise, the use of BS_EXCP has nothing to do with an exception; e.g.
> case 0:
> save_cpu_state(ctx, 1);
> gen_helper_mtc0_status(cpu_env, arg);
> /* BS_STOP isn't good enough here, hflags may have changed. */
> gen_save_pc(ctx->pc + 4);
> ctx->bstate = BS_EXCP;
> rn = "Status";
> break;
where we are in fact relying on (what will become) mips_tr_tb_stop to emit
exit_tb. It would be better to name these uses DISAS_EXIT, which would match
e.g. target/arm.
r~
