Re: [RFC PATCH 1/3] config: provide a fragment to enable gdb for qemu

2018-12-18 Thread Mark Brown
On Tue, Dec 18, 2018 at 10:07:21AM +0100, Arnd Bergmann wrote:
> On Tue, Dec 18, 2018 at 9:45 AM Anders Roxell  
> wrote:
> > On Thu, 13 Dec 2018 at 13:40, Mark Brown  wrote:

> > > Is this specifically for qemu or is this just good for debugging with
> > > GDB in general (eg, via JTAG)?

> > I haven't tried, and I don't have a JTAG so I could test it =/

> The DEBUG_INFO=y and (as a dependency for that) CONFIG_COMPILE_TEST
> are definitely needed for all GDB operation. I would assume that
> the scripts also work with any other gdb environment, but haven't tried 
> either.

I'm fairly sure the requirements are identical, though it has been quite
some time since I tried and I don't have relevant hardware any more so
can't confirm.

> For CONFIG_RANDOMIZE_BASE, I'm not actually sure if that helps or
> not. I think I originally suggested to Anders to turn that off when he
> was analyzing a bug, but I don't know if it helped or if it works just
> as well without that.

Yeah, I'd think it'd be helpful to turn that off.


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Re: [RFC PATCH 1/3] config: provide a fragment to enable gdb for qemu

2018-12-18 Thread Arnd Bergmann
On Tue, Dec 18, 2018 at 9:45 AM Anders Roxell  wrote:
>
> On Thu, 13 Dec 2018 at 13:40, Mark Brown  wrote:
> >
> > On Thu, Dec 13, 2018 at 01:29:08PM +0100, Anders Roxell wrote:
> > > Adding a fragment to make it easier to know what options is needed to
> > > build a kernel to get the that you can debug in qemu.
> >
> > > @@ -0,0 +1,7 @@
> > > +# Enable debug info for gdb
> > > +# CONFIG_COMPILE_TEST is not set
> > > +CONFIG_DEBUG_INFO=y
> > > +CONFIG_GDB_SCRIPTS=y
> >
> > Is this specifically for qemu or is this just good for debugging with
> > GDB in general (eg, via JTAG)?
>
> I haven't tried, and I don't have a JTAG so I could test it =/

The DEBUG_INFO=y and (as a dependency for that) CONFIG_COMPILE_TEST
are definitely needed for all GDB operation. I would assume that
the scripts also work with any other gdb environment, but haven't tried either.

For CONFIG_RANDOMIZE_BASE, I'm not actually sure if that helps or
not. I think I originally suggested to Anders to turn that off when he
was analyzing a bug, but I don't know if it helped or if it works just
as well without that.

Arnd


Re: [RFC PATCH 1/3] config: provide a fragment to enable gdb for qemu

2018-12-18 Thread Anders Roxell
On Thu, 13 Dec 2018 at 13:40, Mark Brown  wrote:
>
> On Thu, Dec 13, 2018 at 01:29:08PM +0100, Anders Roxell wrote:
> > Adding a fragment to make it easier to know what options is needed to
> > build a kernel to get the that you can debug in qemu.
>
> > @@ -0,0 +1,7 @@
> > +# Enable debug info for gdb
> > +# CONFIG_COMPILE_TEST is not set
> > +CONFIG_DEBUG_INFO=y
> > +CONFIG_GDB_SCRIPTS=y
>
> Is this specifically for qemu or is this just good for debugging with
> GDB in general (eg, via JTAG)?

I haven't tried, and I don't have a JTAG so I could test it =/

Cheers,
Anders


Re: [RFC PATCH 1/3] config: provide a fragment to enable gdb for qemu

2018-12-13 Thread Mark Brown
On Thu, Dec 13, 2018 at 01:29:08PM +0100, Anders Roxell wrote:
> Adding a fragment to make it easier to know what options is needed to
> build a kernel to get the that you can debug in qemu.

> @@ -0,0 +1,7 @@
> +# Enable debug info for gdb
> +# CONFIG_COMPILE_TEST is not set
> +CONFIG_DEBUG_INFO=y
> +CONFIG_GDB_SCRIPTS=y

Is this specifically for qemu or is this just good for debugging with
GDB in general (eg, via JTAG)?


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