vhaudiquet
64e19c213a
Minimal freestanding arm64 binary that depthcharge boots as a kernel: parses depthcharge's /firmware/coreboot DTB node, walks the coreboot table, finds LB_TAG_FRAMEBUFFER, and paints red/yellow/green/blue checkpoints (~2s each) into the live boot-splash framebuffer. Verified against coreboot tables header, Linux arm64 booting.rst, and depthcharge's fit.c/boot64.c. Host parser tests pass against the live /sys/firmware/fdt; full red->yellow->green->blue sequence verified end-to-end under qemu-system-aarch64; packed image verifies with the ChromeOS devkeys.
51 lines
1.7 KiB
Bash
Executable File
51 lines
1.7 KiB
Bash
Executable File
#!/bin/sh
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# build.sh — build krane-fb-stub raw arm64 binary.
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# Output: krane-fb-stub.bin (arm64 Linux Image with 64-byte header).
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set -e
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cd "$(dirname "$0")"
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CC=aarch64-linux-gnu-gcc
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OBJCOPY=aarch64-linux-gnu-objcopy
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READELF=aarch64-linux-gnu-readelf
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OBJDUMP=aarch64-linux-gnu-objdump
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CFLAGS="-O2 -ffreestanding -fPIC -fno-builtin -fno-stack-protector \
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-fno-unwind-tables -fno-asynchronous-unwind-tables -mstrict-align \
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-mgeneral-regs-only -Wall -Wextra -Werror"
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${CC} -c stub.S -o stub_head.o
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${CC} -c main.c -o main.o ${CFLAGS}
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${CC} -nostdlib -nostartfiles -static -no-pie -Wl,-T,linker.ld,-n,-z,max-page-size=4096 \
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-o krane-fb-stub.elf stub_head.o main.o
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# The payload is copied to an arbitrary 2MiB-aligned slot with no relocation
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# processing: any dynamic relocation in the linked image is a build failure.
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if ${READELF} -r krane-fb-stub.elf | grep -q R_AARCH64; then
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echo "FATAL: dynamic relocations present:" >&2
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${READELF} -r krane-fb-stub.elf
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exit 1
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fi
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# .bss is not copied by depthcharge; everything we use must be in the file.
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BSS=$(${OBJDUMP} -h krane-fb-stub.elf | awk '$3==".bss" {print $3}')
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if [ -n "$BSS" ]; then
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echo "FATAL: .bss is non-empty; image_size must cover all state" >&2
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exit 1
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fi
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${OBJCOPY} -O binary krane-fb-stub.elf krane-fb-stub.bin
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# Patch image_size (offset 0x10, LE u64) to the final file size.
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python3 - "$PWD/krane-fb-stub.bin" <<'EOF'
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import os, struct, sys
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path = sys.argv[1]
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size = os.path.getsize(path)
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with open(path, "r+b") as f:
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f.seek(0x10)
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f.write(struct.pack("<Q", size))
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print(f"image_size patched: {size} (0x{size:x}) bytes")
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EOF
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echo "OK: krane-fb-stub.bin built."
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${OBJDUMP} -h krane-fb-stub.elf | sed -n '4,12p'
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