Bootrom challenge #7
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Using this toolchain: riscv-collab/riscv-gnu-toolchain@c7fb153 SHA256 f9353bab5e826e937783c9ace7411375af9733c454d3d5f9f365509f2f7a4cdb. `make bootrom.bin` verifies the shasum.
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Using this toolchain:
riscv-collab/riscv-gnu-toolchain@c7fb153
SHA256 f9353bab5e826e937783c9ace7411375af9733c454d3d5f9f365509f2f7a4cdb.
make bootrom.binverifies the shasum.The toolchain given by @tmagik does seem to be close. The relaxation and general compilation is good, but there are a few differences in optimization and codegen. My goal was to make a few small patches that are easy to audit. I've almost succeeded with C tweaks and patching asm, but unfortunately
ux00boot_load_gpt_partition()comes out wildly different so I've just embedded asm. (I'm bummed to not have a better solution, but at ~20 hours it's starting to not be fun, and I have other responsibilities...)ux00boot_ordered.c is made so I can re-order the code to match the image, without actually moving text in a way that would be hard to understand and audit.
Thanks to @SirCmpwn for the dts file, @esmil for misc things like some disassembly and segment alignment, and @tmagik for the pointer to a similar toolchain.
Edit: riscvarchive/riscv-gcc@07b59d4 looks related to the code I see in the shipped image, but using its parent commit or it, I can't seem to get a gcc that compiles the switch() like the ROM does.