Add scripts that enable vmlinux.h generation from scratch

* download-latest-linux-release.sh finds and fetches latest linux
  release from kernel.org
* install-bpftool.sh builds and installs bpftool from source in the
  provided Linux tree
* install-pahole.sh downloads and builds pahole from source
* install-dependencies.sh assumes a clean ubuntu/debian environment
  and set ups packages necessary to build the kernel

All these can be used to run vmlinux.h gen on Github Actions.

Signed-off-by: Ihor Solodrai <[email protected]>

Author: theihor

scripts/download-latest-linux-release.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+set -eux
+
+sudo apt install -y curl jq tar xz-utils
+
+url=$(curl -s https://www.kernel.org/releases.json \
+        | jq -r '.releases[] | select(.moniker == "mainline") | .source')
+
+curl -LO "$url"
+tar -xf $(basename "$url")
+
+dir=$(basename "$url" | sed 's/\.tar\.[gx]z$//')
+mv $dir linux
+
+rm $(basename "$url")

scripts/install-bpftool.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+set -eux
+
+LINUX_REPO=${1:-"./linux"}
+
+if [ ! -d "${LINUX_REPO}" ]; then
+	echo "Error: Linux repo path is not found, LINUX_REPO=$LINUX_REPO"
+	exit 1
+fi
+
+sudo apt install -y llvm libcap-dev libbfd-dev zlib1g-dev
+
+cd "$LINUX_REPO/tools/bpf/bpftool"
+make -j$(nproc)
+sudo make install

scripts/install-dependencies.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+set -eu
+
+# Assume Ubuntu/Debian x86_64
+
+sudo apt update -y
+DEBIAN_FRONTEND=noninteractive sudo -E apt install -y tzdata
+sudo apt install -y bc bison build-essential elfutils flex libdw-dev libelf-dev make ncurses-dev python3-docutils zstd
+

scripts/install-pahole.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+
+set -eux
+
+PAHOLE_ORIGIN=${PAHOLE_ORIGIN:-https://git.kernel.org/pub/scm/devel/pahole/pahole.git}
+PAHOLE_REVISION=${PAHOLE_REVISION:-next}
+
+sudo apt -y install cmake git libdw-dev libelf-dev
+
+WORKSPACE=$(mktemp -d -t pahole.XXXXXX)
+pushd "$WORKSPACE"
+git clone ${PAHOLE_ORIGIN}            \
+        --branch "${PAHOLE_REVISION}" \
+        --depth=1                     \
+        --single-branch
+cd pahole
+mkdir -p build
+cmake -B=build -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr
+make -C build -j$(nproc)
+sudo make -C build install
+popd
+rm -rf "$WORKSPACE"