qemu-arm: Add support for TravisCI

.circleci/config.yml

@@ -147,7 +147,9 @@ workflows:
     jobs:
      - linux-linux
      - linux-netbsd
-     - qemu-arm-linux
-     - qemu-arm-netbsd
+     # FIXME: Forked version of QEMU is needed
+     # - qemu-arm-linux
+     # TODO: Investigate netbsd support for qemu-arm
+     # - qemu-arm-netbsd
      - freebsd-linux
      - freebsd-netbsd

.travis.yml

@@ -1,8 +1,59 @@
-language: c
+language: nix
 
-compiler:
-  - gcc
-  - clang
+env:
+  global:
+    # XXX: Nix on Travis uses the master branch of the nixpkgs repo, meaning we
+    # need to pin nixpkgs to a specific version if we want to avoid frequent
+    # rebuilds of dependant packages.
+    #
+    # TODO: <nixpkgs> should ideally point to the latest stable release.
+    # However, we currently use the unstable release (@ 2019-03-03) since we
+    # depend on NixOS/nixpkgs#52146, which hasn't been merged into stable yet.
+    # It should be possible to use stable once 19.09 is out.
+    - NIX_PATH=nixpkgs=https://github.com/NixOS/nixpkgs-channels/archive/34aa254f9ebf5899636a9927ceefbc9df80230f4.tar.gz
+
+matrix:
+  include:
+    # FIXME: Some of these are disabled for now; additional work is required
+    # for nix support. It didn't even work well without nix anyways because
+    # excessive log output caused Travis to terminate the build process.
+    #
+    # - name: "GCC"
+    #   env: BUILD_TARGET=frankenlibc-gcc
+    # - name: "Clang"
+    #   env: BUILD_TARGET=frankenlibc-clang
+    - name: "QEMU ARM"
+      env: BUILD_TARGET=frankenlibc-arm
+
+git:
+  # XXX: Submodules have to be fetched manually since it frequently times out.
+  submodules: false
+
+cache:
+  timeout: 1000
+  directories:
+    - $HOME/nix.store
+    # XXX: Beware. Desperate attempt to cache the lkl repository.
+    - $TRAVIS_BUILD_DIR/.git/modules
+
+before_cache:
+  - mkdir -p $HOME/nix.store
+  - |
+    nix copy --to file://$HOME/nix.store -f default.nix \
+      "$BUILD_TARGET".buildInputs \
+      "$BUILD_TARGET".nativeBuildInputs \
+      "$BUILD_TARGET".depsBuildBuild
+
+before_install:
+  - travis_wait 30 git submodule update --init --recursive
+  - mkdir -p $HOME/.config/nix
+  - |
+    # XXX: We write the configuration line-by-line, since Travis doesn't seem
+    # to recognize heredoc delimiters for some reason.
+    echo "substituters = file://$HOME/nix.store https://cache.nixos.org/" \
+      >> ~/.config/nix/nix.conf
+    echo "require-sigs = false" \
+      >> ~/.config/nix/nix.conf
 
 script:
-  - ./build.sh
+  - nix-build -A "$BUILD_TARGET"

default.nix

@@ -0,0 +1,26 @@
+{ pkgs ? import <nixpkgs> {} }:
+
+with pkgs;
+
+let
+  callPackage = lib.callPackageWith (pkgs // self);
+
+  self = {
+    frankenlibc-gcc = callPackage ./nix/frankenlibc.nix { };
+
+    frankenlibc-clang = callPackage ./nix/frankenlibc.nix {
+      stdenv = clangStdenv;
+    };
+
+    frankenlibc-arm = callPackage ./nix/frankenlibc.nix {
+      # XXX: We need newlib-nano instead of newlib to compile. See
+      #      NixOS/nixpkgs#51907 for details.
+      stdenv =
+        let armStdenv = mkStdenvNoLibs pkgsCross.arm-embedded.stdenv;
+        in overrideCC armStdenv gcc-arm-embedded;
+    };
+
+    qemu-circle = callPackage ./nix/qemu-circle.nix { };
+  };
+
+in self

nix/frankenlibc.nix

@@ -0,0 +1,25 @@
+{ stdenv, lib, buildPackages, bc, e2fsprogs, python, zlib, qemu-circle }:
+
+stdenv.mkDerivation ({
+  name = "frankenlibc";
+
+  src = lib.cleanSource ../.;
+
+  depsBuildBuild = [ buildPackages.stdenv.cc zlib ];
+  nativeBuildInputs =
+    [ bc e2fsprogs python ] ++ lib.optionals stdenv.isAarch32 [ qemu-circle ];
+
+  buildFlags = if stdenv.isAarch32 then [ "-k" "linux" "qemu-arm" ] else [];
+
+  # TODO: Separate checkPhase from buildPhase.
+  buildPhase = "./build.sh $buildFlags";
+
+  # FIXME: The copied output is not directly usable, since there are absolute
+  # paths everywhere.
+  installPhase = "cp -r . $out";
+}
+// lib.optionalAttrs stdenv.isAarch32 {
+  # XXX: Workaround to prevent Travis from terminating the build by suppressing
+  # log ouput. Travis terminates any build that produce logs exceeding 4MB.
+  fixupPhase = ":";
+})

nix/qemu-circle.nix

@@ -0,0 +1,41 @@
+{ stdenv, fetchurl, fetchFromGitHub, overrideCC, qemu, gcc6, SDL }:
+
+let
+  qemu-circle = qemu.override {
+    hostCpuTargets = [ "arm-softmmu" ];
+    pulseSupport = false;
+    sdlSupport = false; SDL2 = SDL;
+    gtkSupport = false;
+    vncSupport = false;
+    smartcardSupport = false;
+    spiceSupport = false;
+    xenSupport = false;
+    cephSupport = false;
+    openGLSupport = false;
+    virglSupport = false;
+    smbdSupport = false;
+  };
+
+  diffForCommit = commit: "https://github.com/qemu/qemu/commit/${commit}.diff";
+in
+  qemu-circle.overrideAttrs (old: rec {
+    name = "qemu-circle-${version}";
+    version = "2.4.1";
+    sha256 = "19936r6x7wal09zh0f1s5y32v4k4z5nmnfb2jf0padmff3808jl9";
+    src = fetchFromGitHub {
+      owner = "rsta2";
+      repo = "qemu";
+      rev = "7a24a5a051ea83529b057fd18c76ca40eb717392";
+      fetchSubmodules = true;
+      inherit sha256;
+    };
+
+    patches = builtins.tail old.patches ++ [
+      (fetchurl {
+        url = diffForCommit "75e5b70e6b5dcc4f2219992d7cffa462aa406af0";
+        sha256 = "0a9a09xy4iy6gnmhlbgj28pvzxwp7h165s3rvpc9n6b7lbm0dibj";
+      })
+    ];
+
+    stdenv = overrideCC stdenv gcc6;
+  })

tools/qemu-arm.sh

@@ -1,20 +1,31 @@
 #!/bin/bash
 
-LKL_TAP="${LKL_TAP:-tap0}"
+LKL_TAP="${LKL_TAP:-none}"
 LKL_DEBUG="${LKL_DEBUG:-1}"
 LKL_QEMU_CMDLINE=
 BIN_PATH="$1"
 
 main() {
-  sudo env PATH="$PATH" \
+  if [[ "$LKL_TAP" != "none" ]]; then
+    sudo env PATH="$PATH" \
+      qemu-system-arm \
+        $LKL_QEMU_ARGS \
+        -M raspi2 \
+        -nographic \
+        -device usb-net,vlan=0 \
+        -net tap,vlan=0,ifname="$LKL_TAP",script=no,downscript=no \
+        -append "$(build_qemu_cmdline "$@")" \
+        -semihosting -kernel "$BIN_PATH"
+  else
     qemu-system-arm \
       $LKL_QEMU_ARGS \
       -M raspi2 \
       -nographic \
       -device usb-net,vlan=0 \
-      -net tap,vlan=0,ifname="$LKL_TAP",script=no,downscript=no \
+      -net user,vlan=0 \
       -append "$(build_qemu_cmdline "$@")" \
       -semihosting -kernel "$BIN_PATH"
+  fi
 }
 
 build_qemu_cmdline() {