[00/30] 64-bit LoongArch port of QEMU TCG

Message

WANG Xuerui Sept. 20, 2021, 8:04 a.m. UTC

Hi all,

This is a port of QEMU TCG to the brand-new CPU architecture LoongArch,
introduced by Loongson with their 3A5000 chips. Test suite all passed
except one timeout that is test-crypto-tlssession, but this particular
case runs well when relatively few targets are enabled, so it may be
just a case of low performance (4C4T 2.5GHz). I also boot-tested x86_64
(Debian and Gentoo installation CDs) and aarch64 (Debian netboot
installer), and ran riscv64 linux-user emulation with a chroot;
everything seems fine so far.

## About the series

Only the LP64 ABI is supported, as this is the only one fully
implemented and supported by Loongson. 32-bit support is incomplete from
outset, and removed from the very latest upstream submissions, so you
can't even configure for that.

The architecture's documentation is already translated into English;
it can be browsed at https://loongson.github.io/LoongArch-Documentation/.

In this series I made use of generated instruction encodings and
emitters from https://github.com/loongson-community/loongarch-opcodes
(a community project started by myself, something I must admit), as the
LoongArch encoding is highly irregular even for a fixed 32-bit ISA, and
I want to minimize the maintenance burden for future collaboration. This
is something not seen in any of the other TCG ports out there, so I'd
like to see if this is acceptable practice (and also maybe bikeshed the
file name).

Also, I'm not quite familiar with the DWARF spec, so maybe the debug
frame information is not supplied correctly; beware (though all my tests
run fine).

This series touches some of the same files as Song Gao's previous
submission of LoongArch *target* support, which is a bit unfortunate;
one of us will have to rebase after either series gets in. Actual
conflict should only happen on build system bits and include/elf.h,
though, as we're working on entirely different areas.

## How to build and test this

Upstream support for LoongArch is largely WIP for now, which means you
must apply a lot of patches if you want to even cross-build for this arch.
The main sources I used are as follows:

* binutils: https://github.com/xen0n/binutils-gdb/tree/for-gentoo-2.37-v2
  based on https://github.com/loongson/binutils-gdb/tree/loongarch/upstream_v6_a1d65b3
* gcc: https://github.com/xen0n/gcc/tree/for-gentoo-gcc-12-v2
  based on https://github.com/loongson/gcc/tree/loongarch_upstream
* glibc: https://github.com/xen0n/glibc/tree/for-gentoo-glibc-2.34
  based on https://github.com/loongson/glibc/tree/loongarch_2_34_for_upstream
* Linux: https://github.com/xen0n/linux/tree/loongarch-playground
  based on https://github.com/loongson/linux/tree/loongarch-next
* Gentoo overlay: https://github.com/xen0n/loongson-overlay

I have made ready-to-use Gentoo stage3 tarballs, but they're served with
CDN off my personal cloud account, and I don't want the link to be
exposed so that my bills skyrocket; you can reach me off-list to get the
links if you're interested.

As for the hardware availability, the boards can already be bought in
China on Taobao, and I think some people at Loongson might be able to
arrange for testing environments, if testing on real hardware other than
mine is required before merging; they have their in-house Debian spin-off
from the early days of this architecture. Their kernel is
ABI-incompatible with the version being upstreamed and used by me, but
QEMU should work there regardless.

Lastly, I'm new to QEMU development and this is my first patch series
here; apologizes if I get anything wrong, and any help or suggestion is
certainly appreciated!

WANG Xuerui (30):
  elf: Add machine type value for LoongArch
  MAINTAINERS: Add tcg/loongarch entry with myself as maintainer
  tcg/loongarch: Add the tcg-target.h file
  tcg/loongarch: Add generated instruction opcodes and encoding helpers
  tcg/loongarch: Add register names, allocation order and input/output
    sets
  tcg/loongarch: Define the operand constraints
  tcg/loongarch: Implement necessary relocation operations
  tcg/loongarch: Implement the memory barrier op
  tcg/loongarch: Implement tcg_out_mov and tcg_out_movi
  tcg/loongarch: Implement goto_ptr
  tcg/loongarch: Implement sign-/zero-extension ops
  tcg/loongarch: Implement not/and/or/xor/nor/andc/orc ops
  tcg/loongarch: Implement deposit/extract ops
  tcg/loongarch: Implement bswap32_i32/bswap64_i64
  tcg/loongarch: Implement clz/ctz ops
  tcg/loongarch: Implement shl/shr/sar/rotl/rotr ops
  tcg/loongarch: Implement neg/add/sub ops
  tcg/loongarch: Implement mul/mulsh/muluh/div/divu/rem/remu ops
  tcg/loongarch: Implement br/brcond ops
  tcg/loongarch: Implement setcond ops
  tcg/loongarch: Implement tcg_out_call
  tcg/loongarch: Implement simple load/store ops
  tcg/loongarch: Add softmmu load/store helpers, implement
    qemu_ld/qemu_st ops
  tcg/loongarch: Implement tcg_target_qemu_prologue
  tcg/loongarch: Implement exit_tb/goto_tb
  tcg/loongarch: Implement tcg_target_init
  tcg/loongarch: Register the JIT
  configure, meson.build: Mark support for 64-bit LoongArch hosts
  linux-user: Add host dependency for 64-bit LoongArch
  accel/tcg/user-exec: Implement CPU-specific signal handler for
    LoongArch hosts

 MAINTAINERS                           |    5 +
 accel/tcg/user-exec.c                 |   83 ++
 configure                             |    4 +-
 include/elf.h                         |    2 +
 linux-user/host/loongarch64/hostdep.h |   11 +
 meson.build                           |    4 +-
 tcg/loongarch/tcg-insn-defs.c.inc     | 1080 +++++++++++++++++
 tcg/loongarch/tcg-target-con-set.h    |   30 +
 tcg/loongarch/tcg-target-con-str.h    |   26 +
 tcg/loongarch/tcg-target.c.inc        | 1561 +++++++++++++++++++++++++
 tcg/loongarch/tcg-target.h            |  183 +++
 11 files changed, 2987 insertions(+), 2 deletions(-)
 create mode 100644 linux-user/host/loongarch64/hostdep.h
 create mode 100644 tcg/loongarch/tcg-insn-defs.c.inc
 create mode 100644 tcg/loongarch/tcg-target-con-set.h
 create mode 100644 tcg/loongarch/tcg-target-con-str.h
 create mode 100644 tcg/loongarch/tcg-target.c.inc
 create mode 100644 tcg/loongarch/tcg-target.h