Re: [Qemu-devel] [PATCH] gdb: Fix gdb error

[Andreas Färber]

Hi Aneesh,

Am 11.08.2013 20:14, schrieb Aneesh Kumar K.V:
> From: "Aneesh Kumar K.V" <address@hidden>
> 
> Don't update the global register count if not requested.
> Without this patch a remote gdb session gives
> 
> (gdb) target remote localhost:1234
> Remote debugging using localhost:1234
> Remote 'g' packet reply is too long:
> 0000000028000084c000000000ccba50c000000000c ...
> ....
> ...
> (gdb)
> 
> This is a regression introduce by a0e372f0c49ac01faeaeb73a6e8f50e8ac615f34
> 
> Signed-off-by: Aneesh Kumar K.V <address@hidden>

Thanks for tracking this down. I'm willing to include a variation in
today's pull to fix 1.6.0-rc3. However, did you find an explanation
*why* it needs to be like this? I understand it is a revert to using the
static variable, updated to using the CPUClass field rather than the
previous preprocessor constant.

> ---
>  gdbstub.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/gdbstub.c b/gdbstub.c
> index 1af25a6..4b58a1e 100644
> --- a/gdbstub.c
> +++ b/gdbstub.c
> @@ -598,6 +598,12 @@ void gdb_register_coprocessor(CPUState *cpu,
>  {
>      GDBRegisterState *s;
>      GDBRegisterState **p;
> +    static int last_reg;
> +    CPUClass *cc = CPU_GET_CLASS(cpu);
> +
> +    if (!last_reg) {
> +        last_reg = cc->gdb_num_core_regs;
> +    }
>  
>      p = &cpu->gdb_regs;
>      while (*p) {
> @@ -608,19 +614,21 @@ void gdb_register_coprocessor(CPUState *cpu,
>      }
>  
>      s = g_new0(GDBRegisterState, 1);
> -    s->base_reg = cpu->gdb_num_regs;
> +    s->base_reg = last_reg;
>      s->num_regs = num_regs;
>      s->get_reg = get_reg;
>      s->set_reg = set_reg;
>      s->xml = xml;
>  
>      /* Add to end of list.  */
> -    cpu->gdb_num_regs += num_regs;
> +    last_reg += num_regs;
>      *p = s;
>      if (g_pos) {
>          if (g_pos != s->base_reg) {
>              fprintf(stderr, "Error: Bad gdb register numbering for '%s'\n"
>                      "Expected %d got %d\n", xml, g_pos, s->base_reg);

> +        } else {
> +            cpu->gdb_num_regs = last_reg;

This bit looks wrong to me - it is updating the per-CPU count with the
global value. Could you retest without this please?

Regards,
Andreas

>          }
>      }
>  }
> 


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