[PATCH bpf-next v2 0/9] Enable cpumasks to be used as kptrs

[David Vernet <void@manifault.com>]

This is part 2 of https://lore.kernel.org/all/20230119235833.2948341-1-void@manifault.com/

Changelog:
----------
v1 -> v2:
- Put back 'static' keyword in bpf_find_btf_id()
  (kernel test robot <lkp@intel.com>)
- Surround cpumask kfuncs in __diag() blocks to avoid no-prototype build
  warnings (kernel test robot <lkp@intel.com>)
- Enable ___init suffixes to a type definition to signal that a type is
  a nocast alias of another type. That is, that when passed to a kfunc
  that expects one of the two types, the verifier will reject the other
  even if they're equivalent according to the C standard (Kumar and
  Alexei)
- Reject NULL for all trusted args, not just PTR_TO_MEM (Kumar)
- Reject both NULL and PTR_MAYBE_NULL for all trusted args (Kumar and
  Alexei )
- Improve examples given in cpumask documentation (Alexei)
- Use __success macro for nested_trust test (Alexei)
- Fix comment typo in struct bpf_cpumask comment header.
- Fix another example in the bpf_cpumask doc examples.
- Add documentation for ___init suffix change mentioned above.

David Vernet (9):
  bpf: Enable annotating trusted nested pointers
  bpf: Allow trusted args to walk struct when checking BTF IDs
  bpf: Disallow NULLable pointers for trusted kfuncs
  bpf: Enable cpumasks to be queried and used as kptrs
  selftests/bpf: Add nested trust selftests suite
  selftests/bpf: Add selftest suite for cpumask kfuncs
  bpf/docs: Document cpumask kfuncs in a new file
  bpf/docs: Document how nested trusted fields may be defined
  bpf/docs: Document the nocast aliasing behavior of ___init

 Documentation/bpf/cpumasks.rst                | 396 +++++++++++++++
 Documentation/bpf/index.rst                   |   1 +
 Documentation/bpf/kfuncs.rst                  |  76 ++-
 include/linux/bpf.h                           |   8 +
 kernel/bpf/Makefile                           |   1 +
 kernel/bpf/btf.c                              | 122 +++++
 kernel/bpf/cpumask.c                          | 477 ++++++++++++++++++
 kernel/bpf/verifier.c                         |  67 ++-
 tools/testing/selftests/bpf/DENYLIST.s390x    |   2 +
 .../selftests/bpf/prog_tests/cgrp_kfunc.c     |   4 +-
 .../selftests/bpf/prog_tests/cpumask.c        |  74 +++
 .../selftests/bpf/prog_tests/nested_trust.c   |  12 +
 .../selftests/bpf/prog_tests/task_kfunc.c     |   4 +-
 .../selftests/bpf/progs/cpumask_common.h      | 114 +++++
 .../selftests/bpf/progs/cpumask_failure.c     | 125 +++++
 .../selftests/bpf/progs/cpumask_success.c     | 426 ++++++++++++++++
 .../selftests/bpf/progs/nested_trust_common.h |  12 +
 .../bpf/progs/nested_trust_failure.c          |  33 ++
 .../bpf/progs/nested_trust_success.c          |  31 ++
 19 files changed, 1976 insertions(+), 9 deletions(-)
 create mode 100644 Documentation/bpf/cpumasks.rst
 create mode 100644 kernel/bpf/cpumask.c
 create mode 100644 tools/testing/selftests/bpf/prog_tests/cpumask.c
 create mode 100644 tools/testing/selftests/bpf/prog_tests/nested_trust.c
 create mode 100644 tools/testing/selftests/bpf/progs/cpumask_common.h
 create mode 100644 tools/testing/selftests/bpf/progs/cpumask_failure.c
 create mode 100644 tools/testing/selftests/bpf/progs/cpumask_success.c
 create mode 100644 tools/testing/selftests/bpf/progs/nested_trust_common.h
 create mode 100644 tools/testing/selftests/bpf/progs/nested_trust_failure.c
 create mode 100644 tools/testing/selftests/bpf/progs/nested_trust_success.c

-- 
2.39.0