复现问题
发现rva22s64出现hang，复现脚本
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$QEMU -machine virt -nographic -m 2G -smp 2 \
-cpu rva22s64 \
-bios $d/fw_jump.elf \
-kernel $d/kernel-latest &> log &
只要看到最后停在哪里就可以知道有没有问题
bisect脚本
稍微改造一下上面的测试用例
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$ cat check-qemu
#!/bin/bash
QEMU_SRC=~/qemu
QEMU=$QEMU_SRC/install/bin/qemu-system-riscv64
pushd $QEMU_SRC
make -j 64 install
popd
$d=~/wufei/rvsp
tm=$(date +%s)
log=$d/log-$tm
$QEMU -machine virt -nographic -m 2G -smp 2 \
-cpu rva22s64 \
-bios $d/fw_jump.elf \
-kernel $d/kernel-latest &> log &
pid=$!
sleep 5
kill -9 $pid
if tail -1 $log | grep MEDELEG; then
exit 1
else
exit 0
fi
执行bisect
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$ git bisect start master dfa3c4c57e
$ git bisect run check-qemu
d06f28db60c536b9d7f159adedca397979f6e5ca is the first bad commit
commit d06f28db60c536b9d7f159adedca397979f6e5ca
Author: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Date: Fri Jan 5 20:05:33 2024 -0300
target/riscv: move 'mmu' to riscv_cpu_properties[]
bisect特别适合这类任务，总共不到一小时内定位问题，直接上去调试代码肯定需要更多时间。