[PATCH bpf-next v3 00/12] bpf: Support 64-bit pointers to kfuncs

[Ilya Leoshkevich <iii@linux.ibm.com>]

v2: https://lore.kernel.org/bpf/20230215235931.380197-1-iii@linux.ibm.com/
v2 -> v3: Drop BPF_HELPER_CALL (Alexei).
          Drop the merged check_subprogs() cleanup.
          Adjust arm, sparc and i386 JITs.
          Fix a few portability issues in test_verifier.
          Fix a few sparc64 issues.
          Trim s390x denylist.

v1: https://lore.kernel.org/bpf/20230214212809.242632-1-iii@linux.ibm.com/T/#t
v1 -> v2: Add BPF_HELPER_CALL (Stanislav).
          Add check_subprogs() cleanup - noticed while reviewing the
          code for BPF_HELPER_CALL.
          Drop WARN_ON_ONCE (Stanislav, Alexei).
          Add bpf_jit_get_func_addr() to x86_64 JIT.

Hi,

This series solves the problems outlined in [1, 2, 3]. The main problem
is that kfuncs in modules do not fit into bpf_insn.imm on s390x; the
secondary problem is that there is a conflict between "abstract" XDP
metadata function BTF ids and their "concrete" addresses.

The solution is to keep fkunc BTF ids in bpf_insn.imm, and put the
addresses into bpf_kfunc_desc, which does not have size restrictions.

Regtested with test_verifier and test_progs on x86_64 and s390x.
Regtested with test_verifier only on arm, sparc64 and i386.

[1] https://lore.kernel.org/bpf/Y9%2FyrKZkBK6yzXp+@krava/
[2] https://lore.kernel.org/bpf/20230128000650.1516334-1-iii@linux.ibm.com/
[3] https://lore.kernel.org/bpf/20230128000650.1516334-32-iii@linux.ibm.com/

Best regards,
Ilya

Ilya Leoshkevich (12):
  selftests/bpf: Finish folding after BPF_FUNC_csum_diff
  selftests/bpf: Fix test_verifier on 32-bit systems
  sparc: Update maximum errno
  bpf: sparc64: Emit fixed-length instructions for BPF_PSEUDO_FUNC
  bpf: sparc64: Fix jumping to the first insn
  bpf: sparc64: Use 32-bit tail call index
  bpf, arm: Use bpf_jit_get_func_addr()
  bpf: sparc64: Use bpf_jit_get_func_addr()
  bpf: x86: Use bpf_jit_get_func_addr()
  bpf, x86_32: Use bpf_jit_get_func_addr()
  bpf: Support 64-bit pointers to kfuncs
  selftests/bpf: Trim DENYLIST.s390x

 arch/arm/net/bpf_jit_32.c                     | 27 +++++--
 arch/sparc/include/asm/errno.h                | 10 +++
 arch/sparc/kernel/entry.S                     |  2 +-
 arch/sparc/kernel/process.c                   |  6 +-
 arch/sparc/kernel/syscalls.S                  |  2 +-
 arch/sparc/net/bpf_jit_comp_64.c              | 50 +++++++-----
 arch/x86/net/bpf_jit_comp.c                   | 15 +++-
 arch/x86/net/bpf_jit_comp32.c                 | 27 +++++--
 include/linux/bpf.h                           |  2 +
 kernel/bpf/core.c                             | 21 ++++-
 kernel/bpf/verifier.c                         | 79 ++++++-------------
 tools/testing/selftests/bpf/DENYLIST.s390x    | 20 -----
 tools/testing/selftests/bpf/test_verifier.c   |  5 ++
 .../selftests/bpf/verifier/array_access.c     | 10 ++-
 .../selftests/bpf/verifier/atomic_fetch_add.c |  2 +-
 .../selftests/bpf/verifier/bpf_get_stack.c    |  2 +-
 tools/testing/selftests/bpf/verifier/calls.c  |  4 +-
 .../testing/selftests/bpf/verifier/map_kptr.c |  2 +-
 .../testing/selftests/bpf/verifier/map_ptr.c  |  2 +-
 19 files changed, 164 insertions(+), 124 deletions(-)
 create mode 100644 arch/sparc/include/asm/errno.h

-- 
2.39.1