On 27 November 2013 18:27, Wookey wookey@wookware.org wrote:
+++ Christopher Covington [2013-11-27 11:17 -0500]:
In my opinion, the nicer solution is to port the semihosting boot wrapper to 64-bit. We've done that internally, but don't currently have approval to share that work. It's not too difficult though--basically just drop the AArch64 boot.S into the 32-bit bootwrapper code with semihosting support and you're most of the way there. A simulator with instruction tracing or stepping is probably necessary for debugging.
I didn't understand a lot of those words, but it really doesn't sound easier than 'a little shell script that lets me change the command line in a working .axf kernel'. Turns out said shell script was actually written wearing a linaro hat so I'll stick it somewhere and add a wiki page.
Christopher is advocating that somebody should fix the boot wrapper, so you have a single trivial .axf file which doesn't include the kernel at all, and you then pass on the command line to the model (a) the kernel you actually want to boot and (b) the command line to be passed to the kernel. This is how the boot wrapper for 32 bit models works (because I did that because I was fed up with rerolling .axf files for new kernels). It's much nicer to use and means you don't have to mess around with altering .axf files at all. I entirely agree that it would be a good idea if somebody wanted to do this work :-)
-- PMM