This series replaces the single patch "LoongArch: bpf: Support kptr xchg
inline" with four logically separate changes as requested during review.
Patch 1 fixes BPF JIT atomic xchg to use amswap_db.{w,d}, which provide
the full barrier semantics required by LKMM for value-returning atomic RMW.
This is independent of kptr inlining.
Patch 2 advertises bpf_jit_supports_ptr_xchg() so the verifier may inline
bpf_kptr_xchg() to BPF_XCHG on LoongArch.
Patches 3 and 4 extend bpf selftests: functional coverage via
./bench -d 30 -w 5 -p 1 kptr-xchg --nr-loops 256
Chenguang Zhao (4):
LoongArch: bpf: Use amswap_db for BPF atomic xchg
LoongArch: bpf: Advertise JIT support for kptr xchg inline
selftests/bpf: Enable kptr_xchg_inline test on LoongArch
selftests/bpf: Add kptr-xchg benchmark
arch/loongarch/include/asm/inst.h | 2 +
arch/loongarch/net/bpf_jit.c | 9 +-
tools/testing/selftests/bpf/Makefile | 2 +
tools/testing/selftests/bpf/bench.c | 2 +
.../selftests/bpf/benchs/bench_kptr_xchg.c | 96 +++++++++++++++++++
.../bpf/prog_tests/kptr_xchg_inline.c | 3 +-
.../selftests/bpf/progs/kptr_xchg_bench.c | 48 ++++++++++
7 files changed, 159 insertions(+), 3 deletions(-)
create mode 100644 tools/testing/selftests/bpf/benchs/bench_kptr_xchg.c
create mode 100644 tools/testing/selftests/bpf/progs/kptr_xchg_bench.c
---
v2:
- Split the original single patch into four separate commits.
- Switch BPF_W/BPF_DW atomic xchg from plain amswap{w,d} to barrier-aware
amswapdbw/amswapdbd.
v1:
- https://lore.kernel.org/all/[email protected]/
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2.25.1
