[v3,bpf-next,0/4] Add support of pointer to struct in global functions

Message

Dmitrii Banshchikov Feb. 12, 2021, 8:56 p.m. UTC

This patchset adds support of pointers to type with known size among
global function arguments.

The motivation is to overcome the limit on the maximum number of allowed
arguments and avoid tricky and unoptimal ways of passing arguments.

A referenced type may contain pointers but access via such pointers
cannot be veirified currently.

v2 -> v3
 - Fix reg ID generation
 - Fix commit description
 - Fix typo
 - Fix tests

v1 -> v2:
 - Allow pointer to any type with known size rather than struct only
 - Allow pointer in global functions only
 - Add more tests
 - Fix wrapping and v1 comments

Dmitrii Banshchikov (4):
  bpf: Rename bpf_reg_state variables
  bpf: Extract nullable reg type conversion into a helper function
  bpf: Support pointers in global func args
  selftests/bpf: Add unit tests for pointers in global functions

 include/linux/bpf_verifier.h                  |   2 +
 kernel/bpf/btf.c                              |  71 +++++++---
 kernel/bpf/verifier.c                         | 113 +++++++++++----
 .../bpf/prog_tests/global_func_args.c         |  60 ++++++++
 .../bpf/prog_tests/test_global_funcs.c        |   8 ++
 .../selftests/bpf/progs/test_global_func10.c  |  29 ++++
 .../selftests/bpf/progs/test_global_func11.c  |  19 +++
 .../selftests/bpf/progs/test_global_func12.c  |  21 +++
 .../selftests/bpf/progs/test_global_func13.c  |  24 ++++
 .../selftests/bpf/progs/test_global_func14.c  |  21 +++
 .../selftests/bpf/progs/test_global_func15.c  |  22 +++
 .../selftests/bpf/progs/test_global_func16.c  |  22 +++
 .../selftests/bpf/progs/test_global_func9.c   | 132 ++++++++++++++++++
 .../bpf/progs/test_global_func_args.c         |  91 ++++++++++++
 14 files changed, 588 insertions(+), 47 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/global_func_args.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_global_func10.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_global_func11.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_global_func12.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_global_func13.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_global_func14.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_global_func15.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_global_func16.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_global_func9.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_global_func_args.c