23.9.1. QEMU -d tracing
QEMU also has a second trace mechanism in addition to -trace, find out the events with:
./run -- -d help
Let’s pick the one that dumps executed instructions, in_asm:
./run --eval './linux/poweroff.out' -- -D out/trace.txt -d in_asm less out/trace.txt
Sample output excerpt:
---------------- IN: 0xfffffff0: ea 5b e0 00 f0 ljmpw $0xf000:$0xe05b ---------------- IN: 0x000fe05b: 2e 66 83 3e 88 61 00 cmpl $0, %cs:0x6188 0x000fe062: 0f 85 7b f0 jne 0xd0e1
TODO: after IN:, symbol names are meant to show, which is awesome, but I don’t get any. I do see them however when running a bare metal example from: https://github.com/cirosantilli/newlib-examples/tree/900a9725947b1f375323c7da54f69e8049158881
TODO: what is the point of having two mechanisms, -trace and -d? -d tracing is cool because it does not require a messy recompile, and it can also show symbols.