14.3. gem5 graphic mode
gem5 does not have a "text mode", since it cannot redirect the Linux terminal to same host terminal where the executable is running: you are always forced to connect to the terminal with gem-shell.
TODO could not get it working on x86_64, only ARM.
More concretely, first build the kernel with the gem5 arm Linux kernel patches, and then run:
./build-linux \ --arch arm \ --custom-config-file-gem5 \ --linux-build-id gem5-v4.15 \ ; ./run --arch arm --emulator gem5 --linux-build-id gem5-v4.15
and then on another shell:
vinagre localhost:5900
The CONFIG_LOGO penguin only appears after several seconds, together with kernel messages of type:
[ 0.152755] [drm] found ARM HDLCD version r0p0 [ 0.152790] hdlcd 2b000000.hdlcd: bound virt-encoder (ops 0x80935f94) [ 0.152795] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). [ 0.152799] [drm] No driver support for vblank timestamp query. [ 0.215179] Console: switching to colour frame buffer device 240x67 [ 0.230389] hdlcd 2b000000.hdlcd: fb0: frame buffer device [ 0.230509] [drm] Initialized hdlcd 1.0.0 20151021 for 2b000000.hdlcd on minor 0
The port 5900 is incremented by one if you already have something running on that port, gem5 stdout tells us the right port on stdout as:
system.vncserver: Listening for connections on port 5900
and when we connect it shows a message:
info: VNC client attached
Alternatively, you can also dump each new frame to an image file with --frame-capture:
./run \ --arch arm \ --emulator gem5 \ --linux-build-id gem5-v4.15 \ -- --frame-capture \ ;
This creates on compressed PNG whenever the screen image changes inside the m5out directory with filename of type:
frames_system.vncserver/fb.<frame-index>.<timestamp>.png.gz
It is fun to see how we get one new frame whenever the white underscore cursor appears and reappears under the penguin!
The last frame is always available uncompressed at: system.framebuffer.png.
TODO kmscube failed on aarch64 with:
kmscube[706]: unhandled level 2 translation fault (11) at 0x00000000, esr 0x92000006, in libgbm.so.1.0.0[7fbf6a6000+e000]
Tested on: 38fd6153d965ba20145f53dc1bb3ba34b336bde9