Re: [PATCH] Add proper single-step support for arm-none-eabi

[Luis Machado <lgustavo at codesourcery dot com>]

On 04/05/2017 06:30 AM, Yao Qi wrote:
> Elouan Appere <elouan.appere@club-internet.fr> writes:
>
> > This commit adds proper support for single-stepping on arm-none-eabi.
> >
> > arm_software_single_step is now always registered in arm_gdbarch_init (arm-tdep.c) before calling gdbarch_osabi_init. Additionally, arm_software_single_step now checks whether or not the target supports single-stepping itself (which is the case for most simulators, emulators, etc.).
>
> This changes the arm-none-eabi gdb software single step behavior.
> Currently, arm-none-eabi gdb doesn't do software single step, and
> debugging stubs support hardware single step "silently".
> With your patch applied, arm-none-eabi gdb thinks existing debugging
> stubs don't support hardware single step, it changes to software single
> step, because they don't tell gdb they do support hardware single step.
>
> Why do you need software single step in bare-metal debugging?

We have bare-metal debugging for arm-eabi and it uses hardware/stub 
single-stepping, so i'd rather not have this change of defaults as Yao 
pointed out.

But i agree that a more reasonable mechanism to enable/disable 
hardware/stub single-stepping in an automatically way would be great.