On Wed, Oct 09, 2019 at 01:14:56PM -0700, Andrii Nakryiko wrote: > With BPF maps supporting direct map access (currently, array_map w/ single > element, used for global data) that are read-only both from system call and > BPF side, it's possible for BPF verifier to track its contents as known > constants. > > Now it's possible for user-space control app to pre-initialize read-only map > (e.g., for .rodata section) with user-provided flags and parameters and rely > on BPF verifier to detect and eliminate dead code resulting from specific > combination of input parameters. > > v1->v2: > - BPF_F_RDONLY means nothing, stick to just map->frozen (Daniel); > - stick to passing just offset into map_direct_value_addr (Martin). > > Andrii Nakryiko (2): > bpf: track contents of read-only maps as scalars > selftests/bpf: add read-only map values propagation tests > > kernel/bpf/verifier.c | 57 ++++++++++- > .../selftests/bpf/prog_tests/rdonly_maps.c | 99 +++++++++++++++++++ > .../selftests/bpf/progs/test_rdonly_maps.c | 83 ++++++++++++++++ > 3 files changed, 237 insertions(+), 2 deletions(-) > create mode 100644 tools/testing/selftests/bpf/prog_tests/rdonly_maps.c > create mode 100644 tools/testing/selftests/bpf/progs/test_rdonly_maps.c Applied, thanks!
