Hi!
This set starts with adding functional tests for JSET instruction.
Next verifier's understanding of JSET is improved and relevant tests
follow. These changes allow for better dead code elimination.
Dead code removal is the next part. For root user only all code deemed
dead by the verifier path walk is removed. Conditional branches which
land on dead code are converted to unconditional jumps, and unconditional
jumps by 0 are removed (these most likely result from earlier dead code
elimination).
Advanced JITs need to be informed about those optimizations, as they
build up their state prior to verification.
First nfp patch is a slight clarification to the code, to avoid
confusion. Next skip marking is split per reason. We use skip flag
to mark BPF instructions which won't be reflected in NFP machine code.
There are safety checks which should only apply to some types of skips
so we need a way to express the reason instruction is skipped. Next
JSET code gen is improved. And finally we take advantage of the dead
code elimination added to the verifier.
Jakub Kicinski (19):
selftests: bpf: add trivial JSET tests
bpf: verifier: teach the verifier to reason about the BPF_JSET
instruction
selftests: bpf: verifier: add tests for JSET interpretation
bpf: verifier: reorder stack size check with dead code sanitization
bpf: change parameters of call/branch offset adjustment
bpf: verifier: hard wire branches to dead code
bpf: verifier: remove dead code
bpf: verifier: remove unconditional branches by 0
selftests: bpf: add tests for dead code removal
selftests: bpf: add missing executables to .gitignore
bpf: verifier: record original instruction index
bpf: notify offload JITs about optimizations
nfp: bpf: don't use instruction number for jump target
nfp: bpf: split up the skip flag
nfp: bpf: remove the trivial JSET optimization
nfp: bpf: optimize codegen for JSET with a constant
nfp: bpf: save original program length
nfp: bpf: support optimizing dead branches
nfp: bpf: support removing dead code
drivers/net/ethernet/netronome/nfp/bpf/jit.c | 69 ++-
drivers/net/ethernet/netronome/nfp/bpf/main.h | 33 +-
.../net/ethernet/netronome/nfp/bpf/offload.c | 5 +-
.../net/ethernet/netronome/nfp/bpf/verifier.c | 63 ++-
include/linux/bpf.h | 7 +
include/linux/bpf_verifier.h | 6 +
include/linux/filter.h | 1 +
kernel/bpf/core.c | 52 +-
kernel/bpf/offload.c | 35 ++
kernel/bpf/verifier.c | 241 ++++++++-
tools/testing/selftests/bpf/.gitignore | 1 +
tools/testing/selftests/bpf/test_btf.c | 138 +++++-
tools/testing/selftests/bpf/test_verifier.c | 465 ++++++++++++++++--
13 files changed, 1006 insertions(+), 110 deletions(-)
--
2.19.2
