Re: [Qemu-devel] [PATCH v3] target/xtensa: linux-user: add call0 ABI support

[Laurent Vivier <laurent@vivier.eu>]

Le 26/08/2019 à 21:58, Max Filippov a écrit :
> Xtensa binaries built for call0 ABI don't rotate register window on
> function calls and returns. Invocation of signal handlers from the
> kernel is therefore different in windowed and call0 ABIs.
> There's currently no way to determine xtensa ELF binary ABI from the
> binary itself. Add handler for the -xtensa-abi-call0 command line
> parameter/QEMU_XTENSA_ABI_CALL0 envitonment variable to the qemu-user
> and record ABI choice. Use it to initialize PS.WOE in xtensa_cpu_reset.
> Check PS.WOE in setup_rt_frame to determine how a signal should be
> delivered.
> 
> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
> ---
> Changes v2->v3:
> 
> - revert to checking PS.WOE in the setup_rt_frame
> 
> Changes v1->v2:
> 
> - move handling of QEMU_XTENSA_ABI_CALL0 to linux-user/main.c
> - check xtensa_abi_call0 instead of PS.WOE in the setup_rt_frame
> 
>  linux-user/main.c          | 17 +++++++++++++++++
>  linux-user/xtensa/signal.c | 25 +++++++++++++++++--------
>  target/xtensa/cpu.c        | 24 ++++++++++++++++++++----
>  target/xtensa/cpu.h        |  3 +++
>  4 files changed, 57 insertions(+), 12 deletions(-)
> 
> diff --git a/linux-user/main.c b/linux-user/main.c
> index 47917bbb20fc..9e50b2d2a92f 100644
> --- a/linux-user/main.c
> +++ b/linux-user/main.c
> @@ -393,6 +393,13 @@ static void handle_arg_trace(const char *arg)
>      trace_file = trace_opt_parse(arg);
>  }
>  
> +#if defined(TARGET_XTENSA)
> +static void handle_arg_abi_call0(const char *arg)
> +{
> +    xtensa_set_abi_call0();
> +}
> +#endif
> +
>  struct qemu_argument {
>      const char *argv;
>      const char *env;
> @@ -446,6 +453,10 @@ static const struct qemu_argument arg_table[] = {
>       "",           "[[enable=]<pattern>][,events=<file>][,file=<file>]"},
>      {"version",    "QEMU_VERSION",     false, handle_arg_version,
>       "",           "display version information and exit"},
> +#if defined(TARGET_XTENSA)
> +    {"xtensa-abi-call0", "QEMU_XTENSA_ABI_CALL0", false, handle_arg_abi_call0,
> +     "",           "assume CALL0 Xtensa ABI"},
> +#endif
>      {NULL, NULL, false, NULL, NULL, NULL}
>  };
>  
> @@ -710,6 +721,12 @@ int main(int argc, char **argv, char **envp)
>          }
>      }
>  
> +#if defined(TARGET_XTENSA)
> +    if (getenv("QEMU_XTENSA_ABI_CALL0")) {
> +        xtensa_set_abi_call0();
> +    }

Not needed, this is done by parse_args() that checks
getenv(arginfo->env) and calls arginfo->handle_opt()
(handle_arg_abi_call0()).

Except that, it looks good.

Reviewed-by: Laurent Vivier <laurent@vivier.eu>