kernel-selftest: Fix building the net selftests

The net selftests generate their netlink code with tools/net/ynl, which
needs the netlink specs from Documentation/netlink, python3 with pyyaml
and jsonschema, and the top-level MAINTAINERS file: ynl_gen_c.py finds
the kernel root by walking up until it sees MAINTAINERS and loops
forever when it is not there. libbpf needs elfutils and zlib,
reuseport_bpf_numa numactl and tcp_mmap openssl.

net/lib installs the whole ynl tree, so drop its build artifacts and
bytecode, which trip the staticdev and buildpaths QA checks, and pass
the prefix maps to clang so the BPF objects don't carry build paths
either.

The python tests load the netlink specs at runtime, so add pyyaml there
as well.

AI-Generated: Uses Claude Code
Signed-off-by: Khem Raj <khem.raj@oss.qualcomm.com>

meta-oe/recipes-kernel/kernel-selftest/kernel-selftest.bb

@@ -5,6 +5,9 @@ LICENSE = "GPL-2.0-only"
 LIC_FILES_CHKSUM = "file://COPYING;md5=bbea815ee2795b2f4230826c0c6b8814"
 
 DEPENDS = "rsync-native llvm-native libcap"
+# net: libbpf (elfutils, zlib), YNL code generation (python3-pyyaml-native,
+# python3-jsonschema-native), reuseport_bpf_numa (numactl) and tcp_mmap (openssl)
+DEPENDS += "elfutils numactl openssl python3-jsonschema-native python3-pyyaml-native zlib"
 
 S = "${UNPACKDIR}"
 
@@ -49,7 +52,7 @@ PACKAGECONFIG[mm] = ",,libcap liburing numactl, libgcc bash"
 do_patch[depends] += "virtual/kernel:do_shared_workdir"
 do_compile[depends] += "virtual/kernel:do_install"
 
-inherit module-base kernel-arch ptest siteinfo
+inherit module-base kernel-arch ptest python3native siteinfo
 
 DEBUG_PREFIX_MAP:remove = "-fcanon-prefix-map"
 
@@ -123,7 +126,7 @@ EXTRA_OEMAKE = '\
     CC="${CC} ${DEBUG_PREFIX_MAP}" \
     AR="${AR}" \
     LD="${LD}" \
-    CLANG="clang -fno-stack-protector -target ${TARGET_ARCH} ${TOOLCHAIN_OPTIONS} -isystem ${S} -D__WORDSIZE=\'64\' -Wno-error=unused-command-line-argument" \
+    CLANG="clang -fno-stack-protector -target ${TARGET_ARCH} ${TOOLCHAIN_OPTIONS} ${DEBUG_PREFIX_MAP} -ffile-prefix-map=${STAGING_KERNEL_BUILDDIR}=/usr/src/kernel -isystem ${S} -D__WORDSIZE=\'64\' -Wno-error=unused-command-line-argument" \
     DESTDIR="${D}" \
     V=1 \
 '
@@ -136,6 +139,8 @@ EXTRA_OEMAKE:append:toolchain-clang = "\
 CLEANBROKEN = "1"
 
 KERNEL_SELFTEST_SRC ?= "Makefile \
+                        Documentation/netlink \
+                        MAINTAINERS \
                         include \
                         kernel \
                         lib \
@@ -187,6 +192,13 @@ do_install() {
     if [ -e ${D}/usr/kernel-selftest/bpf/test_offload.py ]; then
         sed -i -e '1s,#!.*python3,#! /usr/bin/env python3,' ${D}/usr/kernel-selftest/bpf/test_offload.py
     fi
+    # net/lib installs the whole tools/net/ynl tree, including its build
+    # artifacts and the bytecode from running it at build time; only the
+    # python library is used at runtime.
+    if [ -d ${D}/usr/kernel-selftest/net/lib/ynl ]; then
+        find ${D}/usr/kernel-selftest/net/lib/ynl \( -name '*.a' -o -name '*.o' -o -name '*.d' \) -delete
+        find ${D}/usr/kernel-selftest/net/lib/ynl -name __pycache__ -type d -prune -exec rm -rf {} +
+    fi
     chown root:root  -R ${D}/usr/kernel-selftest
 }
 
@@ -227,6 +239,8 @@ FILES:${PN} += "/usr/kernel-selftest"
 # needs to enforce per-test timeouts; busybox has no timeout applet by default.
 # mount_setattr_test creates an ext4 image with mkfs.ext4.
 RDEPENDS:${PN} += "python3 perl perl-module-io-handle bash libcap libgcc coreutils e2fsprogs-mke2fs"
+# The net python tests load netlink specs with the YNL library.
+RDEPENDS:${PN} += "python3-pyyaml"
 
 INSANE_SKIP:${PN} += "libdir"