Hi all! This patchset adds kernel support for BPF load-acquire and store-release instructions (for background, please see [1]), including core/verifier, arm64 JIT compiler, and Documentation/ changes. x86-64 and riscv64 are also planned to be supported. The corresponding LLVM changes can be found at: https://github.com/llvm/llvm-project/pull/108636 Following RFC 9669, 7.3. Adding Instructions [2], this patchset adds two conformance groups for the new instructions: * atomic32v2: includes "atomic32", plus the new 8-, 16- and 32-bit atomic load-acquire and store-release instructions * atomic64v2: includes "atomic64" and "atomic32v2", plus the new 64-bit atomic load-acquire and store-release instructions See patch 8/8 for details; please suggest if you believe the new instructions should be grouped differently. RFC v1: https://lore.kernel.org/all/cover.1734742802.git.yepeilin@xxxxxxxxxx This patchset has been reorganized based on comments and suggestions from Xu and Eduard. Notable changes since RFC v1: o 1-2/8: minor verifier.c refactoring patches o 3/8: core/verifier changes * (Eduard) handle load-acquire properly in backtrack_insn() * (Eduard) avoid skipping checks (e.g., bpf_jit_supports_insn()) for load-acquires * track the value stored by store-releases, just like how non-atomic STX instructions are handled [3] * (Eduard) add missing link in commit message * (Eduard) always print 'r' for disasm.c changes o 4/8: arm64/insn: avoid treating load_acq/store_rel as load_ex/store_ex o 5/8: arm64/insn: add load_acq/store_rel * (Xu) include Should-Be-One (SBO) bits in "mask" and "value", to avoid setting fixed bits during runtime (JIT-compile time) o 6/8: arm64 JIT compiler changes * (Xu) use emit_a64_add_i() for "pointer + offset" to optimize code emission o 7/8: selftests * (Eduard) avoid adding new tests to the 'test_verifier' runner * add more tests, e.g., checking mark_precise logic o 8/8: instruction-set.rst changes Please refer to individual kernel patches (and LLVM commits) for details. Any feedback would be much appreciated! [1] https://lore.kernel.org/all/20240729183246.4110549-1-yepeilin@xxxxxxxxxx/ [2] https://www.rfc-editor.org/rfc/rfc9669.html#section-7.3 [3] Specifically, for store-releases, make sure we do that check_mem_access(..., BPF_WRITE, ...) call with @value_regno equals 'src_reg' instead of -1. Thanks, Peilin Ye (8): bpf/verifier: Factor out atomic_ptr_type_ok() bpf/verifier: Factor out check_atomic_rmw() bpf: Introduce load-acquire and store-release instructions arm64: insn: Add BIT(23) to {load,store}_ex's mask arm64: insn: Add load-acquire and store-release instructions bpf, arm64: Support load-acquire and store-release instructions selftests/bpf: Add selftests for load-acquire and store-release instructions bpf, docs: Update instruction-set.rst for load-acquire and store-release instructions .../bpf/standardization/instruction-set.rst | 114 ++++++++++-- arch/arm64/include/asm/insn.h | 12 +- arch/arm64/lib/insn.c | 28 +++ arch/arm64/net/bpf_jit.h | 20 +++ arch/arm64/net/bpf_jit_comp.c | 92 +++++++++- include/linux/filter.h | 2 + include/uapi/linux/bpf.h | 13 ++ kernel/bpf/core.c | 41 ++++- kernel/bpf/disasm.c | 12 ++ kernel/bpf/verifier.c | 165 +++++++++++++++--- tools/include/uapi/linux/bpf.h | 13 ++ .../selftests/bpf/prog_tests/arena_atomics.c | 61 ++++++- .../selftests/bpf/prog_tests/atomics.c | 57 +++++- .../selftests/bpf/prog_tests/verifier.c | 4 + .../selftests/bpf/progs/arena_atomics.c | 62 ++++++- tools/testing/selftests/bpf/progs/atomics.c | 62 ++++++- .../bpf/progs/verifier_load_acquire.c | 92 ++++++++++ .../selftests/bpf/progs/verifier_precision.c | 39 +++++ .../bpf/progs/verifier_store_release.c | 153 ++++++++++++++++ 19 files changed, 988 insertions(+), 54 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/verifier_load_acquire.c create mode 100644 tools/testing/selftests/bpf/progs/verifier_store_release.c -- 2.48.1.262.g85cc9f2d1e-goog