Merge branch 'local-vmtest-enhancement-and-rv64-enabled'

Pu Lehui says:

====================
Local vmtest enhancement and RV64 enabled

Patch 1-3 fix some problem about bpf selftests. Patch 4 add local rootfs
image support for vmtest. Patch 5 enable cross-platform testing for
vmtest. Patch 6-10 enable vmtest on RV64.

We can now perform cross platform testing for riscv64 bpf using the
following command:

PLATFORM=riscv64 CROSS_COMPILE=riscv64-linux-gnu- \
  tools/testing/selftests/bpf/vmtest.sh \
  -l <path of local rootfs image> -- \
  ./test_progs -d \
      \"$(cat tools/testing/selftests/bpf/DENYLIST.riscv64 \
          | cut -d'#' -f1 \
          | sed -e 's/^[[:space:]]*//' \
                -e 's/[[:space:]]*$//' \
          | tr -s '\n' ',' \
      )\"

For better regression, we rely on commit [0]. And since the work of riscv
ftrace to remove stop_machine atomic replacement is in progress, we also
need to revert commit [1] [2].

The test platform is x86_64 architecture, and the versions of relevant
components are as follows:
    QEMU: 8.2.0
    CLANG: 17.0.6 (align to BPF CI)
    ROOTFS: ubuntu noble (generated by [3])

Link: https://lore.kernel.org/all/20240831071520.1630360-1-pulehui@huaweicloud.com/
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3308172276db
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7caa9765465f
Link: https://github.com/libbpf/ci/blob/main/rootfs/mkrootfs_debian.sh
v3:
- Use llvm static linking when detecting that feature-llvm is enabled
- Add Acked-by by Eduard

v2: https://lore.kernel.org/all/20240904141951.1139090-1-pulehui@huaweicloud.com/
- Drop patch about relaxing Zbb insns restrictions.
- Add local rootfs image support
- Add description about running vmtest on RV64
- Fix some problem about bpf selftests

v1: https://lore.kernel.org/all/20240328124916.293173-1-pulehui@huaweicloud.com/
====================

Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20240905081401.1894789-1-pulehui@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>