Building steps on WSL2/Win11 (Ubuntu 22.04)

[inkydragon]

经过一些尝试可以在 qemu 上运行 hello。
记录一下对应的修改。
待整理并优化、去除不必要的步骤后，可以添加到现有的文档中。

安装 riscv 工具链

参考文档：编译工具链 toolchains - XiangShan 官方文档

• 按照文档中的说明安装工具链，这里选择 riscv32-elf-ubuntu-22.04-gcc-nightly-2024.12.16-nightly.tar.xz
  • 这里选择最新的版本 2024.12.16
  • 需要 riscv64 或其他 ubuntu 版本注意自行选择

下载并安装

## 新建工具链所在文件夹
mkdir ~/riscv/
cd ~/riscv/

## 下载工具链
wget https://mirror.iscas.ac.cn/riscv-toolchains/release/riscv-collab/riscv-gnu-toolchain/Nightly%3A%20December%2016%2C%202024/riscv32-elf-ubuntu-22.04-gcc-nightly-2024.12.16-nightly.tar.xz
# wget https://mirror.iscas.ac.cn/riscv-toolchains/release/riscv-collab/riscv-gnu-toolchain/Nightly%3A%20December%2016%2C%202024/riscv64-elf-ubuntu-22.04-gcc-nightly-2024.12.16-nightly.tar.xz

## 解压
tar xvf riscv32-elf-ubuntu-22.04-gcc-nightly-2024.12.16-nightly.tar.xz -C riscv/
# tar xvf riscv64-elf-ubuntu-22.04-gcc-nightly-2024.12.16-nightly.tar.xz -C riscv/

## 重命名工具链名称。可以实现 rv32/64 共存
mv riscv riscv32
# mv riscv riscv64

验证工具链安装

~$ cd ~/riscv/riscv32/
~/riscv/riscv32$ ls
bin  include  lib  libexec  riscv32-unknown-elf  share
~/riscv/riscv32$ pwd
/home/cyhan/riscv/riscv32
# 记下 pwd 的输出，稍后使用

添加到环境变量中

修改 ~/.bashrc
如使用 vim: vim ~/.bashrc
在末尾或合适的地方添加以下行：

# riscv
export PATH=:/home/cyhan/riscv/riscv32/bin:${PATH}
# export PATH=:/home/cyhan/riscv/riscv64/bin:${PATH}

:wq 保存并退出；
source ~/.bashrc 加载修改

验证工具链安装

~$ riscv32-unknown-elf-  # 按 TAB 键补全可选项
riscv32-unknown-elf-addr2line      riscv32-unknown-elf-g++            riscv32-unknown-elf-gcov-dump      riscv32-unknown-elf-lto-dump       riscv32-unknown-elf-size
riscv32-unknown-elf-ar             riscv32-unknown-elf-gcc            riscv32-unknown-elf-gcov-tool      riscv32-unknown-elf-nm             riscv32-unknown-elf-strings
riscv32-unknown-elf-as             riscv32-unknown-elf-gcc-14.2.0     riscv32-unknown-elf-gdb            riscv32-unknown-elf-objcopy        riscv32-unknown-elf-strip
riscv32-unknown-elf-c++            riscv32-unknown-elf-gcc-ar         riscv32-unknown-elf-gdb-add-index  riscv32-unknown-elf-objdump
riscv32-unknown-elf-c++filt        riscv32-unknown-elf-gcc-nm         riscv32-unknown-elf-gprof          riscv32-unknown-elf-ranlib
riscv32-unknown-elf-cpp            riscv32-unknown-elf-gcc-ranlib     riscv32-unknown-elf-ld             riscv32-unknown-elf-readelf
riscv32-unknown-elf-elfedit        riscv32-unknown-elf-gcov           riscv32-unknown-elf-ld.bfd         riscv32-unknown-elf-run
~$ riscv32-unknown-elf-gcc --version
riscv32-unknown-elf-gcc () 14.2.0
Copyright (C) 2024 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

安装 qemu

使用系统自带的 qemu （版本较老，但够用）

sudo apt update
sudo apt install qemu-system-riscv32

验证安装：

~$ qemu-system-riscv32 --version
QEMU emulator version 6.2.0 (Debian 1:6.2+dfsg-2ubuntu6.24)
Copyright (c) 2003-2021 Fabrice Bellard and the QEMU Project developers

编译项目

patchs

toolchains/riscv32-unknown-elf.lua

diff --git a/toolchains/riscv32-unknown-elf.lua b/toolchains/riscv32-unknown-elf.lua
index b5ef32a..3a00b1a 100644
--- a/toolchains/riscv32-unknown-elf.lua
+++ b/toolchains/riscv32-unknown-elf.lua
@@ -1,5 +1,5 @@
-PATH = "D:\\My\\plugin\\riscv32-gnu-toolchain-win"
-BINDIR =PATH.."\\bin"
+PATH = "/home/cyhan/riscv/riscv32"
+BINDIR =PATH.."/bin"
 PREFIX = "riscv32-unknown-elf-"
 
 TOOLCHAIN_NAME = "riscv32-unknown-elf"

xscript/qemu-board-config.lua

• 这里加入 -mfloat-abi=softfp:
  是为了解决报错：libgcc.a(_ffssi2.o): can't link double-float modules with soft-float modules
  参考：linux - can't link double-float modules with soft-float modules riscv compiler - Stack Overflow

diff --git a/xscript/qemu-board-config.lua b/xscript/qemu-board-config.lua
index 326f3ea..4965f0e 100644
--- a/xscript/qemu-board-config.lua
+++ b/xscript/qemu-board-config.lua
@@ -74,7 +74,7 @@ local testcase_config = {
         crt = "riscv", 
         envs = {
             DEFINE = " ",
-            DEVICE = " -mcmodel=medany -mstrict-align -march=rv32imac -mabi=ilp32",
+            DEVICE = " -mcmodel=medany -mstrict-align -march=rv32imac -mabi=ilp32 -mfloat-abi=softfp",
             DEBUG  = " -gdwarf-2 "
         },
         flags = {

xscript/mlibc-config.lua

• 这里如果指定 -mfloat-abi 会报错

diff --git a/xscript/mlibc-config.lua b/xscript/mlibc-config.lua
index 878d292..2a9616a 100644
--- a/xscript/mlibc-config.lua
+++ b/xscript/mlibc-config.lua
@@ -30,7 +30,7 @@ local mlibc_config = {
     ["riscv32"] = {
         target = "riscv32",
         toolchain = "riscv32-unknown-elf",
-        arch_flags = " -mcmodel=medany -march=rv32imac ",
+        arch_flags = " -mcmodel=medany -march=rv32imac -mabi=ilp32",
         define_flags = " "
     }
 }

编译

# 配置工具链
# 注意这里不能省略后面的 config 选项，不然默认使用 arm 工具链，然后提示找不到工具链
xmake f -p cross --toolchain=riscv32-unknown-elf --crt-arch=riscv32 --mlibc-arch=riscv32 --qemu-board=qemu-virt-riscv32
# 编译
xmake

xmake build mlibc
xmake build crt0

运行 hello

# 进入文件夹
cd helloworld/qemu/qemu-virt-riscv32

新建 qemu.sh (实际上是复制了 qemu.bat)

qemu-system-riscv32 -machine virt -nographic -m 256M \
    -kernel qemu-virt-riscv32.elf -device virtio-serial-device

直接运行提示缺少固件（有点怀疑是 qemu 的问题）

$ ./qemu.sh
qemu-system-riscv32: Unable to load the RISC-V firmware "opensbi-riscv32-generic-fw_dynamic.bin"

下载固件

参考：Getting Started | OS in 1,000 Lines

$ curl -LO https://github.com/qemu/qemu/raw/v6.2.0/pc-bios/opensbi-riscv32-generic-fw_dynamic.bin

再次运行成功。这里最后是个死循环，会一直卡着（按 Ctrl + a；然后按 x 键，退出 qemu）。

$ ./qemu.sh

OpenSBI v0.9
   ____                    _____ ____ _____
  / __ \                  / ____|  _ \_   _|
 | |  | |_ __   ___ _ __ | (___ | |_) || |
 | |  | | '_ \ / _ \ '_ \ \___ \|  _ < | |
 | |__| | |_) |  __/ | | |____) | |_) || |_
  \____/| .__/ \___|_| |_|_____/|____/_____|
        | |
        |_|

Platform Name             : riscv-virtio,qemu
Platform Features         : timer,mfdeleg
Platform HART Count       : 1
Firmware Base             : 0x80000000
Firmware Size             : 100 KB
Runtime SBI Version       : 0.2

Domain0 Name              : root
Domain0 Boot HART         : 0
Domain0 HARTs             : 0*
Domain0 Region00          : 0x80000000-0x8001ffff ()
Domain0 Region01          : 0x00000000-0xffffffff (R,W,X)
Domain0 Next Address      : 0x80200000
Domain0 Next Arg1         : 0x8f000000
Domain0 Next Mode         : S-mode
Domain0 SysReset          : yes

Boot HART ID              : 0
Boot HART Domain          : root
Boot HART ISA             : rv32imafdcsu
Boot HART Features        : scounteren,mcounteren,time
Boot HART PMP Count       : 16
Boot HART PMP Granularity : 4
Boot HART PMP Address Bits: 32
Boot HART MHPM Count      : 0
Boot HART MHPM Count      : 0
Boot HART MIDELEG         : 0x00000222
Boot HART MEDELEG         : 0x0000b109
Uart Test
Hello mlibc