Apple

On Jun 29, 2016, at 1:54 PM, Brian Bechtel <email@hidden> wrote:
You need "sudo" to modify nvram.  You must reboot after setting nvram, to let the changes take effect. On the target:
sudo nvram boot-args="debug=0x146 kdp_match_name=firewire fwkdp=0x8000"
sudo shutdown -r now
The host needs no boot-args. You do not invoke fwkdp as root; invoke it normally. Open a terminal window and type
fwkdp
fwkdp has a bug in the status message it outputs. It mentions gdb, which is obsolete. Please file a bug report via http://bugreporter.apple.com.
Leave the terminal window with fwkdp open. Open another terminal window, and type
lldb
(lldb) kdp-remote localhost
fwkdp acts as a redirector of packets, making it appear as if your host has panicked, then sending all the packets via firewire to the target.
debug=0x8146 changes the NMI key from Left-⌘ + Right-⌘ + Power to the Power button alone.  That's the 0x8000 bit
debug=0x145 halts at early boot. That's the 0x1 bit.
If those aren't working, you haven't properly set boot-args on the target machine.
On Tue, Jun 28, 2016 at 2:53 PM, Prokash Sinha <email@hidden> wrote:
Hi All,

For 10.11 onward, I’m trying to set up a kernel debug configuration using two machines.

I’ve followed quite a few online blog and mailing list archive from here. But I was not able to connect the target from the host.

I used one or the other boot-args on 10.11 MacBook Air as a target.

nvram boot-args="debug=0x8146 kdp_match_name=firewire fwkdp=0x8000”

nvram boot-args="debug=0x144 kdp_match_name=firewire -v”
nvram boot-args="debug=0x145 kdp_match_name=firewire -v” //halt at boo-time 0x01

So it never halted. Why ???.

Now, on the host side -

$ sudo fwkdp

It gets me messages like this -

KDP Proxy and CoreDump-Receive dual mode active.
Use ‘localhos’ as the KDP target in gdb. — We don’t even have gdb by default right??????

Ready.

On another terminal

$lldb
(lldb) kdp-remote localhost
(lldb) kip-REATTACH failed

Even if I try to issue an NMI by hitting power button on the target, and managed to freeze the system after many many tries, I can not connect to the target.

The configuration (PHY wiring ) is thunderbolt - firewire - thunderbolt.

Any help would be appreciated, specially a proven way to halt, get control, run type scenario on 10.11+

Thank you.
Prokash.

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References:
	>fwkdp setup (From: Prokash Sinha <email@hidden>)
	>Re: fwkdp setup (From: Brian Bechtel <email@hidden>)