Lack of TARGET_ARCH=powerpc support in kgdb from devel/gdb (e.g., -r440115 of /usr/ports): "ABI doesn't support a vmcore target"

[Mark Millard]

On:

# uname -apKU
FreeBSD FBSDG4S 12.0-CURRENT FreeBSD 12.0-CURRENT  r317820M  powerpc powerpc 1200030 1200030

When I attempt to use:

# which kgdb
/usr/local/bin/kgdb

that was from building devel/gdb for:

# svnlite info /usr/ports | grep "Re[plv]"
Relative URL: ^/head
Repository Root: https://svn.freebsd.org/ports
Repository UUID: 35697150-7ecd-e111-bb59-0022644237b5
Revision: 440115
Last Changed Rev: 440115

(built via gcc 4.2.1: not via clang: I
experiment with clang for powerpc and
powerpc64 so I'm being explicit)

I end up getting the following sort of result:

# kgdb /usr/lib/debug/boot/kernel/kernel.debug /var/crash/vmcore.4 
. . .
Reading symbols from /usr/lib/debug/boot/kernel/kernel.debug...done.
ABI doesn't support a vmcore target

That message is from: /usr/ports/devel/gdb/files/kgdb/fbsd-kvm.c . . .

static void
kgdb_trgt_open(const char *arg, int from_tty)
{
        struct fbsd_vmcore_ops *ops = (struct fbsd_vmcore_ops *)
            gdbarch_data (target_gdbarch(), fbsd_vmcore_data);
. . .
        if (ops == NULL || ops->supply_pcb == NULL || ops->cpu_pcb_addr == NULL)
                error ("ABI doesn't support a vmcore target");
. . .

It appears that there is no kernel debugging
supported for TARGET_ARCH=powerpc currently.
(The system no longer has its own gdb related
materials.)

===
Mark Millard
markmi at dsl-only.net