[edk2-devel] Help with debugging

[Ethin Probst]

Hey all,

So Leif and I have discussed this at length but I thought I'd reach
out to all of you for more help.

I'm having a lot of trouble debugging my UEFI app. Here's how I do things:

- I load the app using uefi-run
(https://github.com/Richard-W/uefi-run) like this (from the main EDK
II directory): uefi-run -b Build/OvmfX64/DEBUG_GCC5/FV/OVMF.fd
Build/OvmfX64/DEBUG_GCC5/X64/Shell.efi -- -M q35 -m 24G -usb -device
qemu-xhci -device usb-audio,audiodev=audio -audiodev alsa,id=audio -s
-debugcon file:../debug.log -global isa-debugcon.iobase=0x402
-nographic
Or:
uefi-run -b Build/OvmfX64/DEBUG_GCC5/FV/OVMF.fd
Build/OvmfX64/DEBUG_GCC5/X64/Shell.efi -- -M q35 -m 24G -usb -device
qemu-xhci -device usb-audio,audiodev=audio -audiodev alsa,id=audio -s
-debugcon stdio -global isa-debugcon.iobase=0x402
- I connect to the remote GDB stub (localhost:1234) and wait until
OVMF gives me the image base. Then I use:
add-symbol-file UsbAudio.debug <image base>
Here's where everything breaks down. One of two things happens at this point:
1. Either I get the wrong debug information (I get source code but the
image isn't loaded anymore), and resetting the system and placing a
breakpoint (either software or hardware) has no effect; or
2. If I use CpuBreakpoint(), the firmware gives me the registers and
the image base and entry point addresses, and then appears to just sit
there waiting for something. Once I load the symbols using the image
base it gives me, I can't actually do anything in the debugger; I
can't list code because I get "1 in <artificial>", I can't jump into
my code without triggering a general protection exception or not
actually causing anything to happen... You get the idea.

So I'm really, really confused on what's going wrong. Do you guys have
any advice?

-- 
Signed,
Ethin D. Probst


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