Re: [Qemu-devel] [PATCH 4/5] gdbstub: support for gdb "detach/kill/quit"

["Edgar E. Iglesias" <edgar.iglesias@axis.com>]

On Thu, May 15, 2008 at 09:11:32AM -0500, Jason Wessel wrote:
> Implement the 'k' gdbserial packet which kills the qemu instance via
> the debugger stub.
> 
> Implement the 'D' detach packet for the gdb stub such that you can
> disconnect gdb with the "detach" command.  This required implementing
> a cpu_breakpoint_remove_all() and a cpu_watchpoint_remove_all()
> function to cleanup all the breakpoints and watchpoints prior to
> leaving the gdb stub else simulation can stop with no debugger
> attached.
> 
> On a '?' packet remove all the breakpoints and watchpoints.  This is
> considered more of a safety net in case you force killed gdb or it
> crashed and you are reconnecting.  The identical behavior exists for
> kgdb in the linux kernel.
>
> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>


Thanks Jason, this one looks good to me.



> ---
>  cpu-all.h |    2 ++
>  exec.c    |   21 +++++++++++++++++++++
>  gdbstub.c |   17 +++++++++++++++++
>  3 files changed, 40 insertions(+), 0 deletions(-)
> 
> diff --git a/cpu-all.h b/cpu-all.h
> index 7e77f76..d71166c 100644
> --- a/cpu-all.h
> +++ b/cpu-all.h
> @@ -760,8 +760,10 @@ void cpu_reset_interrupt(CPUState *env, int mask);
>  
>  int cpu_watchpoint_insert(CPUState *env, target_ulong addr);
>  int cpu_watchpoint_remove(CPUState *env, target_ulong addr);
> +void cpu_watchpoint_remove_all(CPUState *env);
>  int cpu_breakpoint_insert(CPUState *env, target_ulong pc);
>  int cpu_breakpoint_remove(CPUState *env, target_ulong pc);
> +void cpu_breakpoint_remove_all(CPUState *env);
>  
>  #define SSTEP_ENABLE  0x1  /* Enable simulated HW single stepping */
>  #define SSTEP_NOIRQ   0x2  /* Do not use IRQ while single stepping */
> diff --git a/exec.c b/exec.c
> index 2fd0078..8f5c868 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -1139,6 +1139,16 @@ int cpu_watchpoint_remove(CPUState *env, target_ulong addr)
>      return -1;
>  }
>  
> +/* Remove all watchpoints. */
> +void cpu_watchpoint_remove_all(CPUState *env) {
> +    int i;
> +
> +    for (i = 0; i < env->nb_watchpoints; i++) {
> +        tlb_flush_page(env, env->watchpoint[i].vaddr);
> +    }
> +    env->nb_watchpoints = 0;
> +}
> +
>  /* add a breakpoint. EXCP_DEBUG is returned by the CPU loop if a
>     breakpoint is reached */
>  int cpu_breakpoint_insert(CPUState *env, target_ulong pc)
> @@ -1162,6 +1172,17 @@ int cpu_breakpoint_insert(CPUState *env, target_ulong pc)
>  #endif
>  }
>  
> +/* remove all breakpoints */
> +void cpu_breakpoint_remove_all(CPUState *env) {
> +#if defined(TARGET_HAS_ICE)
> +    int i;
> +    for(i = 0; i < env->nb_breakpoints; i++) {
> +        breakpoint_invalidate(env, env->breakpoints[i]);
> +    }
> +    env->nb_breakpoints = 0;
> +#endif
> +}
> +
>  /* remove a breakpoint */
>  int cpu_breakpoint_remove(CPUState *env, target_ulong pc)
>  {
> diff --git a/gdbstub.c b/gdbstub.c
> index 833cdd9..fb2d948 100644
> --- a/gdbstub.c
> +++ b/gdbstub.c
> @@ -1035,6 +1035,12 @@ static int gdb_handle_packet(GDBState *s, CPUState *env, const char *line_buf)
>          /* TODO: Make this return the correct value for user-mode.  */
>          snprintf(buf, sizeof(buf), "S%02x", SIGTRAP);
>          put_packet(s, buf);
> +        /* Remove all the breakpoints when this query is issued,
> +         * because gdb is doing and initial connect and the state
> +         * should be cleaned up.
> +         */
> +        cpu_breakpoint_remove_all(env);
> +        cpu_watchpoint_remove_all(env);
>          break;
>      case 'c':
>          if (*p != '\0') {
> @@ -1058,6 +1064,17 @@ static int gdb_handle_packet(GDBState *s, CPUState *env, const char *line_buf)
>          }
>          gdb_continue(s);
>  	return RS_IDLE;
> +    case 'k':
> +        /* Kill the target */
> +        fprintf(stderr, "\nQEMU: Terminated via GDBstub\n");
> +        exit(0);
> +    case 'D':
> +        /* Detach packet */
> +        cpu_breakpoint_remove_all(env);
> +        cpu_watchpoint_remove_all(env);
> +        gdb_continue(s);
> +        put_packet(s, "OK");
> +        break;
>      case 's':
>          if (*p != '\0') {
>              addr = strtoull(p, (char **)&p, 16);
> -- 
> 1.5.5.1
> 
> 

-- 
Edgar E. Iglesias
Axis Communications AB