Re: [PATCH 20/20] target/loongarch: Add linux-user emulation support

["Alex Bennée" <alex.bennee@linaro.org>]

maobibo <maobibo@loongson.cn> writes:

> 在 2021年06月29日 21:42, Peter Maydell 写道:
>> On Mon, 28 Jun 2021 at 13:05, Song Gao <gaosong@loongson.cn> wrote:
>>>
>>> Add files to linux-user/loongarch64
>>> Add file to default-configs
>>> Add loongarch to target/meson.build
>>>
>>> Signed-off-by: Song Gao <gaosong@loongson.cn>
>>> ---
>>>  MAINTAINERS                                        |   1 +
>>>  default-configs/targets/loongarch64-linux-user.mak |   4 +
>>>  include/elf.h                                      |   2 +
>>>  linux-user/elfload.c                               |  58 ++++
>>>  linux-user/loongarch64/cpu_loop.c                  | 177 ++++++++++++
>>>  linux-user/loongarch64/signal.c                    | 193 +++++++++++++
>>>  linux-user/loongarch64/sockbits.h                  |   1 +
>>>  linux-user/loongarch64/syscall_nr.h                | 307 +++++++++++++++++++++
>>>  linux-user/loongarch64/target_cpu.h                |  36 +++
>>>  linux-user/loongarch64/target_elf.h                |  14 +
>>>  linux-user/loongarch64/target_fcntl.h              |  12 +
>>>  linux-user/loongarch64/target_signal.h             |  28 ++
>>>  linux-user/loongarch64/target_structs.h            |  49 ++++
>>>  linux-user/loongarch64/target_syscall.h            |  46 +++
>>>  linux-user/loongarch64/termbits.h                  | 229 +++++++++++++++
>>>  linux-user/syscall_defs.h                          |   8 +-
>>>  meson.build                                        |   2 +-
>>>  qapi/machine-target.json                           |   4 +-
>>>  target/loongarch/meson.build                       |  19 ++
>>>  target/meson.build                                 |   1 +
>>>  20 files changed, 1185 insertions(+), 6 deletions(-)
>> 
>> This is a massive patch that would benefit from being split up
>> into multiple smaller patches.
>> 
>> I'm told by a kernel developer that loongarch hasn't yet been
>> accepted into the Linux kernel mainline. Until it has been, the
>> syscall ABI for it is not yet stable, so we won't be able to take
>> the linux-user patches for it yet. (We have been burned in the
>> past by taking linux-user architecture support patches without
>> realizing they weren't for a stable ABI, and then being out of
>> sync with the eventual upstream kernel ABI that was accepted.)
>> 
>> We can certainly do code review in the meantime, though.
> Thanks for reviewing the big series patches. It is understandable that
> there should be linux kernel merged for one new architecture support
> firstly, and then there will be linux-user simulator later.
>
> We are planning to submit patch to linux kernel for LoongArch support,
> there is the link:
> https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson.git/log/?h=loongarch-next
>
> And we will continueto  submit softmmu support for LoongArch. And is there
> any extra requirements for softmmu simulation for new architecture,
> such as gcc/binutils/bios?

Ideally if there are some pre-built toolchains either as part of a
distro (we've used Debian Sid before for some) or easily to install in a
docker container as binary tarballs (like we do for tricore) then we can
enable basic check-tcg functionality.

Going forward having stable URLs for test images of distros means we can
also enable check-acceptance tests.

>
> regards
> bibo, mao
>
>
>> 
>> thanks
>> -- PMM
>> 


-- 
Alex Bennée