[PATCH v3 03/10] accel/tcg: Use one_insn_per_tb global instead of old singlestep global

[Richard Henderson]

On 4/17/23 18:40, Peter Maydell wrote:
> The only place left that looks at the old 'singlestep' global
> variable is the TCG curr_cflags() function.  Replace the old global
> with a new 'one_insn_per_tb' which is defined in tcg-all.c and
> declared in accel/tcg/internal.h.  This keeps it restricted to the
> TCG code, unlike 'singlestep' which was available to every file in
> the system and defined in multiple different places for softmmu vs
> linux-user vs bsd-user.
> 
> While we're making this change, use qatomic_read() and qatomic_set()
> on the accesses to the new global, because TCG will read it without
> holding a lock.
> 
> Signed-off-by: Peter Maydell<peter.maydell at linaro.org>
> ---
> In discussion on v2, we talked about combining this with the
> 'nochain' flag so as to have a single 'tcg_cflags_global' that
> held the flags for the current (one_insn_per_tb, nochain) state.
> I have not attempted that here, because it's a little tricky:
>   * util/log.c is built into some binaries that don't have an
>     accelerator at all (the tools), so it can't simply call
>     current_accel() to get the TCG accelerator

Ah ha, yes, tricky.

>   * the initial value of the logging flags is set before the
>     TCG accelerator is even created
> So I leave that to somebody else to have a go at if they like.
> ---
>   accel/tcg/internal.h      | 2 ++
>   include/exec/cpu-common.h | 2 --
>   accel/tcg/cpu-exec.c      | 2 +-
>   accel/tcg/tcg-all.c       | 6 ++++--
>   bsd-user/main.c           | 1 -
>   linux-user/main.c         | 1 -
>   softmmu/globals.c         | 1 -
>   7 files changed, 7 insertions(+), 8 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson at linaro.org>


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