mipigo: remove legacy startup.s in favor of minimal Go ELF loading

mipigo/.gitignore

-__pycache__
-go-ethereum
-sysroot
-test/test
-minigeth
-/minigeth.bin

mipigo/README

-Compiler for minigeth in MIPS
-
-`./build.sh` will build minigeth for MIPS.
-
-startup -- a startup stub which functions as an ELF loader
-test -- contains Go hello world for MIPS
-

mipigo/build.sh

-#!/usr/bin/env bash
-set -e
-
-cd ../minigeth
-export GOOS=linux
-export GOARCH=mips
-export GOMIPS=softfloat
-go build -o ../mipigo/minigeth
-
-cd ../mipigo
-file minigeth
-
-if [[ ! -d venv ]]; then
-    python3 -m venv venv
-fi
-
-source venv/bin/activate
-pip3 install -r requirements.txt
-./compile.py
-deactivate

mipigo/compile.py

-#!/usr/bin/env python3
-import os
-import sys
-import struct
-import hashlib
-from rangetree import RangeTree
-from elftools.elf.elffile import ELFFile
-
-def load_minigeth(fn="minigeth"):
-  elf = open(fn, "rb")
-  data = elf.read()
-  elf.seek(0)
-
-  elffile = ELFFile(elf)
-
-  end_addr = 0
-  for seg in elffile.iter_segments():
-    end_addr = max(end_addr, seg.header.p_vaddr + seg.header.p_memsz)
-
-  # program memory (16 MB)
-  prog_size = (end_addr+0xFFF) & ~0xFFF
-  prog_dat = bytearray(prog_size)
-  print("malloced 0x%x for program" % prog_size)
-
-  for seg in elffile.iter_segments():
-    print(seg.header, hex(seg.header.p_vaddr))
-    prog_dat[seg.header.p_vaddr:seg.header.p_vaddr+len(seg.data())] = seg.data()
-
-  entry = elffile.header.e_entry
-  print("entrypoint: 0x%x" % entry)
-
-  # moved to MIPS
-  sf = os.path.join(os.path.dirname(os.path.abspath(__file__)), "startup", "startup.bin")
-  start = open(sf, "rb").read() + struct.pack(">I", entry)
-  prog_dat[:len(start)] = start
-  entry = 0
-
-  r = RangeTree()
-  found = 0
-  for section in elffile.iter_sections():
-    try:
-      for nsym, symbol in enumerate(section.iter_symbols()):
-        ss = symbol['st_value']
-        se = ss+symbol['st_size']
-        if ss != se:
-          try:
-            r[ss:se] = symbol.name
-          except KeyError:
-            continue
-        #print(nsym, symbol.name, symbol['st_value'], symbol['st_size'])
-        if symbol.name == "runtime.gcenable":
-          print(nsym, symbol.name)
-          # nop gcenable
-          prog_dat[symbol['st_value']:symbol['st_value']+8] = b"\x03\xe0\x00\x08\x00\x00\x00\x00"
-          found += 1
-    except Exception:
-      #traceback.print_exc()
-      pass
-
-  #assert(found == 2)
-  return prog_dat, prog_size, r
-
-
-if __name__ == "__main__":
-  fn = "minigeth"
-  if len(sys.argv) > 1:
-    fn = sys.argv[1]
-
-  prog_dat, prog_size, _ = load_minigeth(fn)
-  print("compiled %d bytes with md5 %s" % (prog_size, hashlib.md5(prog_dat).hexdigest()))
-
-  with open(fn+".bin", "wb") as f:
-    f.write(prog_dat)
\ No newline at end of file

mipigo/requirements.txt

-pyelftools==0.27
-hexdump==3.3
-termcolor==1.1.0
-capstone==4.0.2
-rangetree==1.0
\ No newline at end of file

mipigo/startup/startup.s

-    .section .test, "x"
-    .balign 4
-    .set    noreorder
-    .global test
-    .ent    test
-test:
-
-lui     $sp, 0x7fff
-ori     $sp, 0xd000
-
-# http://articles.manugarg.com/aboutelfauxiliaryvectors.html
-# _AT_PAGESZ = 6
-ori $t0, $0, 6
-sw $t0, 0xC($sp)
-ori $t0, $0, 0x1000
-sw $t0, 0x10($sp)
-
-lw $ra, dat($0)
-jr $ra
-nop
-
-dat:
-
-.end test

mipigo/startup/startup.sh

-#!/usr/bin/env bash
-set -e
-
-../../mipsevm/maketests.py startup.s startup.bin

mipigo/test/test.go

-package main
-
-import (
-	"fmt"
-)
-
-func main() {
-	fmt.Println("hello world")
-	panic("test panic")
-}

mipigo/test/testbuild.sh

-#!/usr/bin/env bash
-set -e
-
-export GOOS=linux
-export GOARCH=mips
-export GOMIPS=softfloat
-go build test.go
-../compile.py test