[v14,01/26] target/loongarch: Add README

This patch gives an introduction to the LoongArch target.

Signed-off-by: Song Gao <gaosong@loongson.cn>
Signed-off-by: Xiaojuan Yang <yangxiaojuan@loongson.cn>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 MAINTAINERS             |  5 +++
 target/loongarch/README | 77 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+)
 create mode 100644 target/loongarch/README

On 1/6/22 17:41, Song Gao wrote:
> This patch gives an introduction to the LoongArch target.
>
> Signed-off-by: Song Gao<gaosong@loongson.cn>
> Signed-off-by: Xiaojuan Yang<yangxiaojuan@loongson.cn>
> Reviewed-by: Richard Henderson<richard.henderson@linaro.org>
> ---
>   MAINTAINERS             |  5 +++
>   target/loongarch/README | 77 +++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 82 insertions(+)
>   create mode 100644 target/loongarch/README
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index f871d759fd..2df0d4a7c2 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -213,6 +213,11 @@ S: Maintained
>   F: target/hppa/
>   F: disas/hppa.c
>   
> +LoongArch TCG CPUS
"TCG CPUs" -- notice the case for the plural "s".
> +M: Song Gao<gaosong@loongson.cn>
> +S: Maintained
> +F: target/loongarch/
> +
>   M68K TCG CPUs
>   M: Laurent Vivier<laurent@vivier.eu>
>   S: Maintained
> diff --git a/target/loongarch/README b/target/loongarch/README
> new file mode 100644
> index 0000000000..d5780c5918
> --- /dev/null
> +++ b/target/loongarch/README
> @@ -0,0 +1,77 @@
> +- Introduction
> +
> +  LoongArch is the general processor architecture of Loongson.
> +
> +  The following versions of the LoongArch core are supported
> +    core: 3A5000
> +https://github.com/loongson/LoongArch-Documentation/releases/download/2021.08.17/LoongArch-Vol1-v1.00-EN.pdf
> +
> +  We can get the latest loongarch documents athttps://github.com/loongson/LoongArch-Documentation/tags.
> +
> +
> +- Linux-user emulation
> +
> +  We already support Linux user emulation. We can use LoongArch cross-tools to build LoongArch executables on X86 machines,
> +  and We can also use qemu-loongarch64 to run LoongArch executables.
> +
> +  1. Install LoongArch cross-tools on X86 machines.
> +
> +    Download cross-tools.
> +
> +      wgethttps://github.com/loongson/build-tools/releases/latest/download/loongarch64-clfs-20211202-cross-tools.tar.xz
> +
> +      tar -vxf loongarch64-clfs-20211202-cross-tools.tar.xz -C /opt
> +
> +    Config cross-tools env.
> +
> +      . setenv.sh
> +
> +      setenv.sh:
> +
> +          #!/bin/sh
> +          set -x
> +          CC_PREFIX=/opt/cross-tools
> +
> +          export PATH=$CC_PREFIX/bin:$PATH
> +          export LD_LIBRARY_PATH=$CC_PREFIX/lib:$LD_LIBRARY_PATH
> +          export LD_LIBRARY_PATH=$CC_PREFIX/loongarch64-unknown-linux-gnu/lib/:$LD_LIBRARY_PATH
> +          set +x
> +
> +  2. Test tests/tcg/multiarch.
> +
> +    ./configure --disable-rdma --disable-pvrdma --prefix=/usr  \
> +            --target-list="loongarch64-linux-user"  \
> +            --disable-libiscsi --disable-libnfs --disable-libpmem \
> +            --disable-glusterfs --enable-libusb --enable-usb-redir \
> +            --disable-opengl --disable-xen --enable-spice --disable-werror \
> +            --enable-debug --disable-capstone --disable-kvm --enable-profiler
> +
> +    cd  build/
> +
> +    make && make check-tcg
> +
> +  3. Run LoongArch system basic command with loongarch-clfs-system.
> +
> +    Download clfs-system.
> +
> +      wgethttps://github.com/loongson/build-tools/releases/latest/download/loongarch64-clfs-system-2021-12-02.tar.bz2
> +
> +      tar -vxf loongarch64-clfs-system-2021-12-02.tar.bz2 -C /opt/clfs
> +      ln -s /opt/clfs/  /opt/clfs/tls
Command with dubious intention -- are you working around some kind of 
LIBPATH priority problem? TLS shouldn't be involved at this level, yet I 
remotely remember that library search paths similar to "/usr/lib/tls" 
were a thing long ago...
> +
> +    Config env.
> +
> +      cp /opt/clfs/lib64/ld-linux-loongarch64.so.1   /lib64
> +
> +      export LD_LIBRARY_PATH="/opt/clfs/lib64"
> +
> +    Run LoongArch system basic command.
> +
> +      ./qemu-loongarch64  /opt/clfs/usr/bin/bash
> +      ./qemu-loongarch64  /opt/clfs/usr/bin/ls
> +      ./qemu-loongarch64  /opt/clfs/usr/bin/pwd
> +      ...
> +
> +
> +- Note.
> +  We can get the latest LoongArch documents or LoongArch tools athttps://github.com/loongson/
I'm afraid this README would require some re-writing due to the amount 
of Chinglish involved, but that's possibly okay after merging. (I don't 
have the time to rewrite this for you currently, so just a mild rant for 
now.)