Re: [Qemu-devel] [PATCH for 4.1] gdbstub: revert to previous set_reg behaviour

[Mark Cave-Ayland]

On 05/07/2019 14:29, Alex Bennée wrote:

> The refactoring of handle_set_reg missed the fact we previously had
> responded with an empty packet when we were not using XML based
> protocols. This broke the fallback behaviour for architectures that
> don't have registers defined in QEMU's gdb-xml directory.
> 
> Revert to the previous behaviour and clean up the commentary for what
> is going on.
> 
> Fixes: 62b3320bddd
> Signed-off-by: Alex Bennée <address@hidden>
> Cc: Jon Doron <address@hidden>
> Cc: Mark Cave-Ayland <address@hidden>
> ---
>  gdbstub.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/gdbstub.c b/gdbstub.c
> index ea3349d1aa..b6df7ee25a 100644
> --- a/gdbstub.c
> +++ b/gdbstub.c
> @@ -1669,12 +1669,23 @@ static void handle_remove_bp(GdbCmdContext *gdb_ctx, 
> void *user_ctx)
>      put_packet(gdb_ctx->s, "E22");
>  }
>  
> +/*
> + * handle_set/get_reg
> + *
> + * Older gdb are really dumb, and don't use 'G/g' if 'P/p' is available.
> + * This works, but can be very slow. Anything new enough to understand
> + * XML also knows how to use this properly. However to use this we
> + * need to define a local XML file as well as be talking to a
> + * reasonably modern gdb. Responding with an empty packet will cause
> + * the remote gdb to fallback to older methods.
> + */
> +
>  static void handle_set_reg(GdbCmdContext *gdb_ctx, void *user_ctx)
>  {
>      int reg_size;
>  
>      if (!gdb_has_xml) {
> -        put_packet(gdb_ctx->s, "E00");
> +        put_packet(gdb_ctx->s, "");
>          return;
>      }
>  
> @@ -1694,11 +1705,6 @@ static void handle_get_reg(GdbCmdContext *gdb_ctx, 
> void *user_ctx)
>  {
>      int reg_size;
>  
> -    /*
> -     * Older gdb are really dumb, and don't use 'g' if 'p' is avaialable.
> -     * This works, but can be very slow.  Anything new enough to
> -     * understand XML also knows how to use this properly.
> -     */
>      if (!gdb_has_xml) {
>          put_packet(gdb_ctx->s, "");
>          return;
> 

Works for me - thanks for the quick response!

Tested-by: Mark Cave-Ayland <address@hidden>


ATB,

Mark.