This plugin generates a binary trace compatible with the excellent uftrace: https://github.com/namhyung/uftrace
In short, it tracks all function calls performed during execution, based on frame pointer analysis. A big advantage over "uftrace record" is that it works in system mode, allowing to trace a full system execution, which was the original goal. It works as well in user mode, but uftrace itself already does this. It's implemented for aarch64 and x86_64. Let's start with concrete examples of the result. First, in system mode, booting a stack using TF-A + U-boot + Linux: - Two first stages of boot sequence in Arm Trusted Firmware (EL3 and S-EL1) https://fileserver.linaro.org/s/kkxBS552W7nYESX/preview - Stat and open syscalls in kernel https://fileserver.linaro.org/s/dXe4MfraKg2F476/preview - Poweroff sequence (from kernel back to firmware, NS-EL2 to EL3) https://fileserver.linaro.org/s/oR2PtyGKJrqnfRf/preview Full trace is available here: https://fileserver.linaro.org/s/WsemLboPEzo24nw/download/aarch64_boot.json.gz You can download and open it on https://ui.perfetto.dev/ to explore it. Second, in user mode, tracing qemu-aarch64 (itself) running git --help: - Loading program and its interpreter https://fileserver.linaro.org/s/fie8JgX76yyL5cq/preview - TB creation https://fileserver.linaro.org/s/GXY6NKMw5EeRCew/preview Full trace is available here: https://fileserver.linaro.org/s/N8X8fnZ5yGRZLsT/download/qemu_aarch64_git_help.json.gz If you had curiosity and now you're ready to give some attention, most of the details you want to read are included in the documentation patch (final one). Overhead is around x5-x15, and long traces can be directly filtered with uftrace if needed. I hope this plugin can help people trying to understand what happens out of the user space, and get a better grasp of how firmwares, bootloader, and kernel interact behind the curtain. v6 -- - fix types and spelling mistakes - use _MAX for privilege level enums - uftrace info file: use empty strings - trace flush: assert we wrote all data - doc: added style for keyboard keys - added URL to document uftrace entry format - updated comment in vcpu_tb_trans to explain why we always instrument the first instruction in tb v5 -- - addressed Alex comments - split plugin implementation in several commits - removed instruction based timestamps (only use time based timestamps) - removed sampling implementation v4 -- - add support for x64 v3 -- - fix missing include unistd.h (build failed on MacOS only) v2 -- - trace active stacks on exit - do not erase map generated in system_emulation - add documentation to generate restricted visual traces around specific events of execution Pierrick Bouvier (9): contrib/plugins/uftrace: skeleton file contrib/plugins/uftrace: define cpu operations and implement aarch64 contrib/plugins/uftrace: track callstack contrib/plugins/uftrace: implement tracing contrib/plugins/uftrace: implement privilege level tracing contrib/plugins/uftrace: generate additional files for uftrace contrib/plugins/uftrace: implement x64 support contrib/plugins/uftrace_symbols.py contrib/plugins/uftrace: add documentation docs/about/emulation.rst | 199 +++++++ contrib/plugins/uftrace.c | 876 +++++++++++++++++++++++++++++ contrib/plugins/meson.build | 3 +- contrib/plugins/uftrace_symbols.py | 152 +++++ 4 files changed, 1229 insertions(+), 1 deletion(-) create mode 100644 contrib/plugins/uftrace.c create mode 100755 contrib/plugins/uftrace_symbols.py -- 2.47.2
