[PATCH v6 00/21] Add LoongArch linux-user emulation support

Song Gao posted 21 patches 1 year, 2 months ago
Test checkpatch failed
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/1631866380-31017-1-git-send-email-gaosong@loongson.cn
There is a newer version of this series
Maintainers: Richard Henderson <richard.henderson@linaro.org>, Riku Voipio <riku.voipio@iki.fi>, Laurent Vivier <laurent@vivier.eu>, Song Gao <gaosong@loongson.cn>, Paolo Bonzini <pbonzini@redhat.com>
MAINTAINERS                                 |    6 +
accel/tcg/user-exec.c                       |   15 +
configs/targets/loongarch64-linux-user.mak  |    3 +
configure                                   |    5 +
disas/loongarch.c                           | 2511 +++++++++++++++++++++++++++
disas/meson.build                           |    1 +
include/disas/dis-asm.h                     |    2 +
include/elf.h                               |    2 +
linux-user/elfload.c                        |   58 +
linux-user/host/loongarch/hostdep.h         |   11 +
linux-user/loongarch64/cpu_loop.c           |   97 ++
linux-user/loongarch64/signal.c             |  162 ++
linux-user/loongarch64/sockbits.h           |    1 +
linux-user/loongarch64/syscall_nr.h         |  312 ++++
linux-user/loongarch64/target_cpu.h         |   35 +
linux-user/loongarch64/target_elf.h         |   14 +
linux-user/loongarch64/target_errno_defs.h  |    7 +
linux-user/loongarch64/target_fcntl.h       |   12 +
linux-user/loongarch64/target_signal.h      |   30 +
linux-user/loongarch64/target_structs.h     |   49 +
linux-user/loongarch64/target_syscall.h     |   46 +
linux-user/loongarch64/termbits.h           |    1 +
linux-user/syscall_defs.h                   |   10 +-
meson.build                                 |    3 +-
scripts/qemu-binfmt-conf.sh                 |    6 +-
target/loongarch/README                     |   76 +
target/loongarch/cpu-param.h                |   19 +
target/loongarch/cpu.c                      |  286 +++
target/loongarch/cpu.h                      |  151 ++
target/loongarch/fpu_helper.c               |  865 +++++++++
target/loongarch/helper.h                   |   97 ++
target/loongarch/insn_trans/trans_arith.c   |  322 ++++
target/loongarch/insn_trans/trans_atomic.c  |  133 ++
target/loongarch/insn_trans/trans_bit.c     |  255 +++
target/loongarch/insn_trans/trans_branch.c  |   85 +
target/loongarch/insn_trans/trans_extra.c   |   87 +
target/loongarch/insn_trans/trans_farith.c  |  108 ++
target/loongarch/insn_trans/trans_fcmp.c    |   59 +
target/loongarch/insn_trans/trans_fcnv.c    |   36 +
target/loongarch/insn_trans/trans_fmemory.c |  187 ++
target/loongarch/insn_trans/trans_fmov.c    |  153 ++
target/loongarch/insn_trans/trans_memory.c  |  235 +++
target/loongarch/insn_trans/trans_shift.c   |  131 ++
target/loongarch/insns.decode               |  480 +++++
target/loongarch/internals.h                |   29 +
target/loongarch/meson.build                |   18 +
target/loongarch/op_helper.c                |   85 +
target/loongarch/translate.c                |  288 +++
target/loongarch/translate.h                |   46 +
target/meson.build                          |    1 +
tests/tcg/configure.sh                      |    1 +
51 files changed, 7626 insertions(+), 6 deletions(-)
create mode 100644 configs/targets/loongarch64-linux-user.mak
create mode 100644 disas/loongarch.c
create mode 100644 linux-user/host/loongarch/hostdep.h
create mode 100644 linux-user/loongarch64/cpu_loop.c
create mode 100644 linux-user/loongarch64/signal.c
create mode 100644 linux-user/loongarch64/sockbits.h
create mode 100644 linux-user/loongarch64/syscall_nr.h
create mode 100644 linux-user/loongarch64/target_cpu.h
create mode 100644 linux-user/loongarch64/target_elf.h
create mode 100644 linux-user/loongarch64/target_errno_defs.h
create mode 100644 linux-user/loongarch64/target_fcntl.h
create mode 100644 linux-user/loongarch64/target_signal.h
create mode 100644 linux-user/loongarch64/target_structs.h
create mode 100644 linux-user/loongarch64/target_syscall.h
create mode 100644 linux-user/loongarch64/termbits.h
create mode 100644 target/loongarch/README
create mode 100644 target/loongarch/cpu-param.h
create mode 100644 target/loongarch/cpu.c
create mode 100644 target/loongarch/cpu.h
create mode 100644 target/loongarch/fpu_helper.c
create mode 100644 target/loongarch/helper.h
create mode 100644 target/loongarch/insn_trans/trans_arith.c
create mode 100644 target/loongarch/insn_trans/trans_atomic.c
create mode 100644 target/loongarch/insn_trans/trans_bit.c
create mode 100644 target/loongarch/insn_trans/trans_branch.c
create mode 100644 target/loongarch/insn_trans/trans_extra.c
create mode 100644 target/loongarch/insn_trans/trans_farith.c
create mode 100644 target/loongarch/insn_trans/trans_fcmp.c
create mode 100644 target/loongarch/insn_trans/trans_fcnv.c
create mode 100644 target/loongarch/insn_trans/trans_fmemory.c
create mode 100644 target/loongarch/insn_trans/trans_fmov.c
create mode 100644 target/loongarch/insn_trans/trans_memory.c
create mode 100644 target/loongarch/insn_trans/trans_shift.c
create mode 100644 target/loongarch/insns.decode
create mode 100644 target/loongarch/internals.h
create mode 100644 target/loongarch/meson.build
create mode 100644 target/loongarch/op_helper.c
create mode 100644 target/loongarch/translate.c
create mode 100644 target/loongarch/translate.h
[PATCH v6 00/21] Add LoongArch linux-user emulation support
Posted by Song Gao 1 year, 2 months ago
Based-on: <20210822035537.283193-6-richard.henderson@linaro.org>
Based-on: <20210618192951.125651-2-richard.henderson@linaro.org>

Hi,

The 'o32' code has been deleted at the latest kernel [1]. This series only support 
linux-user emulation. More about LoongArch at: https://github.com/loongson/

  [1] https://github.com/loongson/linux/tree/loongarch-next

Missing review:
  * 0001-target-loongarch-Add-README.patch
  * 0002-target-loongarch-Add-core-definition.patch
  * 0017-LoongArch-Linux-User-Emulation.patch 

Changes for v6:
  * Resolve patch10 and patch6 code issues. 

Changes for v5:
  * Follow Richard's code review comments [1].
  * Use force_sig_fault().
  * Implement setup_sigtramp.

    [1]: https://patchew.org/QEMU/1630586467-22463-1-git-send-email-gaosong@loongson.cn/


Changes for v4:
  * Update README,add LoongArch linux-user emulation Introduction.
  * Add 'make check-tcg' support(patch 20).
  * Add binfmt config(patch 21).
  * Fix bugs when running loongarch basic commands.


Changes for v3:
  * Split trans.inc.c.
  * Remove csr registers.
  * Delete patchs 2, 4, 5.
  * Follow Richard's code review comments [1].
  * Follow Richard's riscv patches [2].

    [1]: https://patchew.org/QEMU/1626861198-6133-1-git-send-email-gaosong@loongson.cn/
    [2]: https://patchew.org/QEMU/20210823195529.560295-1-richard.henderson@linaro.org/


Changes for v2:
  * Patch 1, remove unnecessary introduction;
  * Patch 3, follow the ARM/AVR pattern to add new CPU features;
  * Patch 6, remove decode_lsx();
  * Patches 7-18, delete opcode definition, modify translation function;
  * Patches 20-22, split V1 patch20 to V2 patch20-22.

V5: https://patchew.org/QEMU/1631624431-30658-1-git-send-email-gaosong@loongson.cn/
V4: https://patchew.org/QEMU/1630586467-22463-1-git-send-email-gaosong@loongson.cn/
V3: https://patchew.org/QEMU/1630048494-2143-1-git-send-email-gaosong@loongson.cn/
V2: https://patchew.org/QEMU/1626861198-6133-1-git-send-email-gaosong@loongson.cn/
V1: https://patchew.org/QEMU/1624881885-31692-1-git-send-email-gaosong@loongson.cn/

Please review!

Thanks.

Song Gao (21):
  target/loongarch: Add README
  target/loongarch: Add core definition
  target/loongarch: Add main translation routines
  target/loongarch: Add fixed point arithmetic instruction translation
  target/loongarch: Add fixed point shift instruction translation
  target/loongarch: Add fixed point bit instruction translation
  target/loongarch: Add fixed point load/store instruction translation
  target/loongarch: Add fixed point atomic instruction translation
  target/loongarch: Add fixed point extra instruction translation
  target/loongarch: Add floating point arithmetic instruction
    translation
  target/loongarch: Add floating point comparison instruction
    translation
  target/loongarch: Add floating point conversion instruction
    translation
  target/loongarch: Add floating point move instruction translation
  target/loongarch: Add floating point load/store instruction
    translation
  target/loongarch: Add branch instruction translation
  target/loongarch: Add disassembler
  LoongArch Linux User Emulation
  default-configs: Add loongarch linux-user support
  target/loongarch: Add target build suport
  target/loongarch: 'make check-tcg' support
  scripts: add loongarch64 binfmt config

 MAINTAINERS                                 |    6 +
 accel/tcg/user-exec.c                       |   15 +
 configs/targets/loongarch64-linux-user.mak  |    3 +
 configure                                   |    5 +
 disas/loongarch.c                           | 2511 +++++++++++++++++++++++++++
 disas/meson.build                           |    1 +
 include/disas/dis-asm.h                     |    2 +
 include/elf.h                               |    2 +
 linux-user/elfload.c                        |   58 +
 linux-user/host/loongarch/hostdep.h         |   11 +
 linux-user/loongarch64/cpu_loop.c           |   97 ++
 linux-user/loongarch64/signal.c             |  162 ++
 linux-user/loongarch64/sockbits.h           |    1 +
 linux-user/loongarch64/syscall_nr.h         |  312 ++++
 linux-user/loongarch64/target_cpu.h         |   35 +
 linux-user/loongarch64/target_elf.h         |   14 +
 linux-user/loongarch64/target_errno_defs.h  |    7 +
 linux-user/loongarch64/target_fcntl.h       |   12 +
 linux-user/loongarch64/target_signal.h      |   30 +
 linux-user/loongarch64/target_structs.h     |   49 +
 linux-user/loongarch64/target_syscall.h     |   46 +
 linux-user/loongarch64/termbits.h           |    1 +
 linux-user/syscall_defs.h                   |   10 +-
 meson.build                                 |    3 +-
 scripts/qemu-binfmt-conf.sh                 |    6 +-
 target/loongarch/README                     |   76 +
 target/loongarch/cpu-param.h                |   19 +
 target/loongarch/cpu.c                      |  286 +++
 target/loongarch/cpu.h                      |  151 ++
 target/loongarch/fpu_helper.c               |  865 +++++++++
 target/loongarch/helper.h                   |   97 ++
 target/loongarch/insn_trans/trans_arith.c   |  322 ++++
 target/loongarch/insn_trans/trans_atomic.c  |  133 ++
 target/loongarch/insn_trans/trans_bit.c     |  255 +++
 target/loongarch/insn_trans/trans_branch.c  |   85 +
 target/loongarch/insn_trans/trans_extra.c   |   87 +
 target/loongarch/insn_trans/trans_farith.c  |  108 ++
 target/loongarch/insn_trans/trans_fcmp.c    |   59 +
 target/loongarch/insn_trans/trans_fcnv.c    |   36 +
 target/loongarch/insn_trans/trans_fmemory.c |  187 ++
 target/loongarch/insn_trans/trans_fmov.c    |  153 ++
 target/loongarch/insn_trans/trans_memory.c  |  235 +++
 target/loongarch/insn_trans/trans_shift.c   |  131 ++
 target/loongarch/insns.decode               |  480 +++++
 target/loongarch/internals.h                |   29 +
 target/loongarch/meson.build                |   18 +
 target/loongarch/op_helper.c                |   85 +
 target/loongarch/translate.c                |  288 +++
 target/loongarch/translate.h                |   46 +
 target/meson.build                          |    1 +
 tests/tcg/configure.sh                      |    1 +
 51 files changed, 7626 insertions(+), 6 deletions(-)
 create mode 100644 configs/targets/loongarch64-linux-user.mak
 create mode 100644 disas/loongarch.c
 create mode 100644 linux-user/host/loongarch/hostdep.h
 create mode 100644 linux-user/loongarch64/cpu_loop.c
 create mode 100644 linux-user/loongarch64/signal.c
 create mode 100644 linux-user/loongarch64/sockbits.h
 create mode 100644 linux-user/loongarch64/syscall_nr.h
 create mode 100644 linux-user/loongarch64/target_cpu.h
 create mode 100644 linux-user/loongarch64/target_elf.h
 create mode 100644 linux-user/loongarch64/target_errno_defs.h
 create mode 100644 linux-user/loongarch64/target_fcntl.h
 create mode 100644 linux-user/loongarch64/target_signal.h
 create mode 100644 linux-user/loongarch64/target_structs.h
 create mode 100644 linux-user/loongarch64/target_syscall.h
 create mode 100644 linux-user/loongarch64/termbits.h
 create mode 100644 target/loongarch/README
 create mode 100644 target/loongarch/cpu-param.h
 create mode 100644 target/loongarch/cpu.c
 create mode 100644 target/loongarch/cpu.h
 create mode 100644 target/loongarch/fpu_helper.c
 create mode 100644 target/loongarch/helper.h
 create mode 100644 target/loongarch/insn_trans/trans_arith.c
 create mode 100644 target/loongarch/insn_trans/trans_atomic.c
 create mode 100644 target/loongarch/insn_trans/trans_bit.c
 create mode 100644 target/loongarch/insn_trans/trans_branch.c
 create mode 100644 target/loongarch/insn_trans/trans_extra.c
 create mode 100644 target/loongarch/insn_trans/trans_farith.c
 create mode 100644 target/loongarch/insn_trans/trans_fcmp.c
 create mode 100644 target/loongarch/insn_trans/trans_fcnv.c
 create mode 100644 target/loongarch/insn_trans/trans_fmemory.c
 create mode 100644 target/loongarch/insn_trans/trans_fmov.c
 create mode 100644 target/loongarch/insn_trans/trans_memory.c
 create mode 100644 target/loongarch/insn_trans/trans_shift.c
 create mode 100644 target/loongarch/insns.decode
 create mode 100644 target/loongarch/internals.h
 create mode 100644 target/loongarch/meson.build
 create mode 100644 target/loongarch/op_helper.c
 create mode 100644 target/loongarch/translate.c
 create mode 100644 target/loongarch/translate.h

-- 
1.8.3.1


Re: [PATCH v6 00/21] Add LoongArch linux-user emulation support
Posted by Song Gao 1 year, 2 months ago
Hi, Richard.

On 09/17/2021 04:12 PM, Song Gao wrote:
> Based-on: <20210822035537.283193-6-richard.henderson@linaro.org>

This patch failed in applying to current master. I am not sure how to use it ...  


Thanks.
Song Gao 


Re: [PATCH v6 00/21] Add LoongArch linux-user emulation support
Posted by Richard Henderson 1 year, 2 months ago
On 9/17/21 1:12 AM, Song Gao wrote:
> The 'o32' code has been deleted at the latest kernel [1]. This series only support
> linux-user emulation.

I have now reviewed all but the linux-user/ portion.

I see that kernel upstreaming is in progress,

https://lore.kernel.org/linux-kernel/20210917035736.3934017-1-chenhuacai@loongson.cn/

so hopefully this will be resolved soon.

Have you started working on system mode support for LoongArch, so that one may run that 
kernel?


r~

Re: [PATCH v6 00/21] Add LoongArch linux-user emulation support
Posted by Song Gao 1 year, 2 months ago
Hi, Richard.

On 09/21/2021 05:17 AM, Richard Henderson wrote:
> On 9/17/21 1:12 AM, Song Gao wrote:
>> The 'o32' code has been deleted at the latest kernel [1]. This series only support
>> linux-user emulation.
> 
> I have now reviewed all but the linux-user/ portion.
> 
Thank you!
> I see that kernel upstreaming is in progress,
> 
> https://lore.kernel.org/linux-kernel/20210917035736.3934017-1-chenhuacai@loongson.cn/
> 
> so hopefully this will be resolved soon.
> 
> Have you started working on system mode support for LoongArch, so that one may run that kernel?
> Yes. We already support running the old kernel, but we don't support running the latest kernel yet.

Song Gao
thanks
> 
> r~


Re: [PATCH v6 00/21] Add LoongArch linux-user emulation support
Posted by WANG Xuerui 1 year, 2 months ago
Hi Song,

On 9/22/21 14:22, Song Gao wrote:
> Hi, Richard.
>
> On 09/21/2021 05:17 AM, Richard Henderson wrote:
>> On 9/17/21 1:12 AM, Song Gao wrote:
>>> The 'o32' code has been deleted at the latest kernel [1]. This series only support
>>> linux-user emulation.
>> I have now reviewed all but the linux-user/ portion.
>>
> Thank you!
>> I see that kernel upstreaming is in progress,
>>
>> https://lore.kernel.org/linux-kernel/20210917035736.3934017-1-chenhuacai@loongson.cn/
>>
>> so hopefully this will be resolved soon.
>>
>> Have you started working on system mode support for LoongArch, so that one may run that kernel?
>> Yes. We already support running the old kernel, but we don't support running the latest kernel yet.

(the reply was at the wrong quotation level, never mind though)

First of all, thanks for your contribution and continued engagement with 
the wider development community! That's what it takes to unlock the 
3A5000 and future products' so many possibilities.

As for the system emulation part, I have some questions though:

- How would you provide the necessary firmware bits? Ideally that would 
be some open-source reference implementation so people would be able to 
collaborate on that front, and to maybe customize for specialized needs 
(e.g. ultra-dense cloud use cases like with Firecracker).

- How is old/new kernel ABI affecting your system-level emulation 
compatibility? IIUC the underlying ISA and chip behavior should be the 
same, only difference would be the firmware-kernel ABI, but again it 
should be just a matter of substituting the right image.

- Would the resulting work support emulating both old-world and 
new-world systems? AFAIK those commercial distros who're VERY early 
adopters of LoongArch are given similarly early toolchains/kernels. They 
belong to the old-world as a result, and are very likely to be stuck on 
the old-world ABI for whole major versions before migrating, if at all 
possible. Closed-source/commercial software also risk being available 
only for the old-world, and it would be extremely important to provide 
some degree of interoperability so that we don't split the ecosystem.

Questions aside, you did a nice work so far; looking forward to your 
system emulation work!


Re: [PATCH v6 00/21] Add LoongArch linux-user emulation support
Posted by gaosong 1 year, 2 months ago
Hi, Xuerui.

&gt; -----Original Messages-----
&gt; From: "WANG Xuerui" <i.qemu@xen0n.name>
&gt; Sent Time: 2021-09-22 17:49:56 (Wednesday)
&gt; To: "Song Gao" <gaosong@loongson.cn>, "Richard Henderson" <richard.henderson@linaro.org>, qemu-devel@nongnu.org
&gt; Cc: peter.maydell@linaro.org, thuth@redhat.com, philmd@redhat.com, yangxiaojuan@loongson.cn, laurent@vivier.eu, peterx@redhat.com, f4bug@amsat.org, alistair.francis@wdc.com, maobibo@loongson.cn, pbonzini@redhat.com, bmeng.cn@gmail.com, alex.bennee@linaro.org, chenhuacai@loongson.cn
&gt; Subject: Re: [PATCH v6 00/21] Add LoongArch linux-user emulation support
&gt; 
&gt; Hi Song,
&gt; 
&gt; On 9/22/21 14:22, Song Gao wrote:
&gt; &gt; Hi, Richard.
&gt; &gt;
&gt; &gt; On 09/21/2021 05:17 AM, Richard Henderson wrote:
&gt; &gt;&gt; On 9/17/21 1:12 AM, Song Gao wrote:
&gt; &gt;&gt;&gt; The 'o32' code has been deleted at the latest kernel [1]. This series only support
&gt; &gt;&gt;&gt; linux-user emulation.
&gt; &gt;&gt; I have now reviewed all but the linux-user/ portion.
&gt; &gt;&gt;
&gt; &gt; Thank you!
&gt; &gt;&gt; I see that kernel upstreaming is in progress,
&gt; &gt;&gt;
&gt; &gt;&gt; https://lore.kernel.org/linux-kernel/20210917035736.3934017-1-chenhuacai@loongson.cn/
&gt; &gt;&gt;
&gt; &gt;&gt; so hopefully this will be resolved soon.
&gt; &gt;&gt;
&gt; &gt;&gt; Have you started working on system mode support for LoongArch, so that one may run that kernel?
&gt; &gt;&gt; Yes. We already support running the old kernel, but we don't support running the latest kernel yet.
&gt; 
&gt; (the reply was at the wrong quotation level, never mind though)
&gt; 
&gt; First of all, thanks for your contribution and continued engagement with 
&gt; the wider development community! That's what it takes to unlock the 
&gt; 3A5000 and future products' so many possibilities.
&gt; 
&gt; As for the system emulation part, I have some questions though:
&gt; 
&gt; - How would you provide the necessary firmware bits? Ideally that would 
&gt; be some open-source reference implementation so people would be able to 
&gt; collaborate on that front, and to maybe customize for specialized needs 
&gt; (e.g. ultra-dense cloud use cases like with Firecracker).
&gt; 

On QEMU, we only support 64 bit, So far, we have no plan to support 32 bit.

As far as I know, LoongArch BIOS is planning to open source.

&gt; - How is old/new kernel ABI affecting your system-level emulation 
&gt; compatibility? IIUC the underlying ISA and chip behavior should be the 
&gt; same, only difference would be the firmware-kernel ABI, but again it 
&gt; should be just a matter of substituting the right image.
&gt;

We only supoort the lastet kernel [1].

[1] https://github.com/loongson/linux/tree/loongarch-next

&gt; - Would the resulting work support emulating both old-world and 
&gt; new-world systems? AFAIK those commercial distros who're VERY early 
&gt; adopters of LoongArch are given similarly early toolchains/kernels. They 
&gt; belong to the old-world as a result, and are very likely to be stuck on 
&gt; the old-world ABI for whole major versions before migrating, if at all 
&gt; possible. Closed-source/commercial software also risk being available 
&gt; only for the old-world, and it would be extremely important to provide 
&gt; some degree of interoperability so that we don't split the ecosystem.

On the basis of supporting the latest kernel, we will try to be compatible with the old version of LoongArch. 
But the result may be incompatible。

Song Gao
thanks.

&gt; Questions aside, you did a nice work so far; looking forward to your 
&gt; system emulation work!
</richard.henderson@linaro.org></gaosong@loongson.cn></i.qemu@xen0n.name>

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Re: [PATCH v6 00/21] Add LoongArch linux-user emulation support
Posted by WANG Xuerui 1 year, 2 months ago
Hi Song,

On 9/23/21 11:09, gaosong wrote:
> > 
> > - How would you provide the necessary firmware bits? Ideally that would 
> > be some open-source reference implementation so people would be able to 
> > collaborate on that front, and to maybe customize for specialized needs 
> > (e.g. ultra-dense cloud use cases like with Firecracker).
> > 
>
> On QEMU, we only support 64 bit, So far, we have no plan to support 32 bit.
IMO it's fine to not support 32-bit for now.
> As far as I know, LoongArch BIOS is planning to open source.
And that's exciting to hear! Really looking forward to that.
> > - How is old/new kernel ABI affecting your system-level emulation 
> > compatibility? IIUC the underlying ISA and chip behavior should be the 
> > same, only difference would be the firmware-kernel ABI, but again it 
> > should be just a matter of substituting the right image.
> >
>
> We only supoort the lastet kernel [1].
>
> [1] https://github.com/loongson/linux/tree/loongarch-next
I may formed the question ambiguously; I'm actually interested in what 
kernel flavor qemu will support emulating, not what qemu runs on. IIUC 
qemu will compile and run fine on both old-world and new-world systems. 
But anyway, we'll find out when your code is out for review.
> > - Would the resulting work support emulating both old-world and 
> > new-world systems? AFAIK those commercial distros who're VERY early 
> > adopters of LoongArch are given similarly early toolchains/kernels. They 
> > belong to the old-world as a result, and are very likely to be stuck on 
> > the old-world ABI for whole major versions before migrating, if at all 
> > possible. Closed-source/commercial software also risk being available 
> > only for the old-world, and it would be extremely important to provide 
> > some degree of interoperability so that we don't split the ecosystem.
>
> On the basis of supporting the latest kernel, we will try to be compatible with the old version of LoongArch.
> But the result may be incompatible。
Thanks for the clarification. Indeed focusing on new-world should be the 
right way to go, adding old-world compatibility later if possible. I 
fear adding compatibility too early would result in a franken-port not 
serving either world well nor maintainable.