| Message ID | 20181213122910.24193-2-anders.roxell@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | Make allmodconfig boot in qemu-arm64 | expand |
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)?
On Thu, 13 Dec 2018 at 13:40, Mark Brown <broonie@kernel.org> 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
On Tue, Dec 18, 2018 at 9:45 AM Anders Roxell <anders.roxell@linaro.org> wrote: > > On Thu, 13 Dec 2018 at 13:40, Mark Brown <broonie@kernel.org> 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
On Tue, Dec 18, 2018 at 10:07:21AM +0100, Arnd Bergmann wrote: > On Tue, Dec 18, 2018 at 9:45 AM Anders Roxell <anders.roxell@linaro.org> wrote: > > On Thu, 13 Dec 2018 at 13:40, Mark Brown <broonie@kernel.org> 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.
diff --git a/kernel/configs/qemu-gdb.config b/kernel/configs/qemu-gdb.config new file mode 100644 index 000000000000..30465905ff93 --- /dev/null +++ b/kernel/configs/qemu-gdb.config @@ -0,0 +1,7 @@ +# Enable debug info for gdb +# CONFIG_COMPILE_TEST is not set +CONFIG_DEBUG_INFO=y +CONFIG_GDB_SCRIPTS=y + +# Easier to debug +# CONFIG_RANDOMIZE_BASE is not set
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. First you need to start qemu with flags '-s -S' and then connect with gdb like below: $ gdb \ ./obj-dir/vmlinux -iex 'add-auto-load-safe-path \ ./obj-dir' -ex 'target remote localhost:1234' Signed-off-by: Anders Roxell <anders.roxell@linaro.org> --- kernel/configs/qemu-gdb.config | 7 +++++++ 1 file changed, 7 insertions(+) create mode 100644 kernel/configs/qemu-gdb.config -- 2.19.2