Compiling Linux kernel with LLVM for mips64el

Hi LLVM and Kernel developers,

I am building Linux Kernel[1] with LLVM toolchain[2] for mips64el. It is just able to workaround[3] build, please teach me how to fix PR38063 and PR38128, thanks a lot!

1. Linux Kernel 4.9 branch GitHub - loongson-community/linux-stable at rebase-4.9

2. Loongson clang version 7.0.0 (git@github.com:Loong-Language/loong-clang.git c36069cffc57a30a20782bf327a87bed4e48a6c2) (git@github.com:Loong-Language/loong-llvm.git 59cb663e72874dda740aa2b18bf47ba65b32fe9b) (based on LLVM 7.0.0svn)
Target: mips64el-redhat-linux
Thread model: posix
InstalledDir: /opt/loong-llvm/bin
Found candidate GCC installation: /usr/lib/gcc/mips64el-redhat-linux/4.9.3
Selected GCC installation: /usr/lib/gcc/mips64el-redhat-linux/4.9.3
Candidate multilib: .;
Selected multilib: .;

3. Ugly workaround in Kernel and Compiler sides Issues · loongson-community/linux-stable · GitHub
$ readelf -h vmlinux
ELF Header:
   Magic: 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
   Class: ELF64
   Version: 1 (current)
   OS/ABI: UNIX - System V
   ABI Version: 0
   Type: EXEC (Executable file)
   Machine: MIPS R3000
   Version: 0x1
   Entry point address: 0xffffffff811c94e0
   Start of program headers: 64 (bytes into file)
   Start of section headers: 37391984 (bytes into file)
   Flags: 0x80000001, noreorder, mips64r2
   Size of this header: 64 (bytes)
   Size of program headers: 56 (bytes)
   Number of program headers: 2
   Size of section headers: 64 (bytes)
   Number of section headers: 27
   Section header string table index: 24

4. Failed Checking missing-syscalls for O32 https://bugs.llvm.org/show_bug.cgi?id=38063
5. Unsupported inline asm tying incompatible types https://bugs.llvm.org/show_bug.cgi?id=38128