Port the BPF stack argument feature (BPF_REG_PARAMS / r11) to the RV64 JIT, matching what x86 and arm64 already do.
BPF-to-BPF calls keep all extra arguments on the stack. For kfunc calls, the JIT loads arguments 6-8 into A5-A7 at the call site to satisfy the RISC-V C calling convention. Tested on riscv64 QEMU with LLVM main [1]; BPF-to-BPF and kfunc selftests pass. [1] https://github.com/llvm/llvm-project/pull/189060 Signed-off-by: Feng Jiang <[email protected]> --- Changes in v3: - Drop the exceptions.c guard change: the guarded programs use bpf_throw(), unsupported by the RV64 JIT, so the test is denylisted on riscv64 and the guard has no effect. (BPF CI) - Link to v2: https://lore.kernel.org/r/[email protected] Changes in v2: - Sign-extend 32-bit kfunc arguments passed on the stack (args 9+), matching the register path and the RISC-V psABI. (Sashiko) - Restrict the riscv selftest guard to __riscv_xlen == 64 so the tests are not enabled on RV32. (Sashiko) - Link to v1: https://lore.kernel.org/r/[email protected] --- Feng Jiang (2): bpf, riscv: Add BPF stack arguments support for RV64 JIT selftests/bpf: Enable stack argument tests for RV64 arch/riscv/net/bpf_jit.h | 1 + arch/riscv/net/bpf_jit_comp64.c | 79 +++++++++++++++++++++- arch/riscv/net/bpf_jit_core.c | 4 ++ .../selftests/bpf/progs/btf__stack_arg_precision.c | 3 +- .../bpf/progs/btf__verifier_stack_arg_order.c | 3 +- tools/testing/selftests/bpf/progs/stack_arg.c | 3 +- .../testing/selftests/bpf/progs/stack_arg_kfunc.c | 3 +- .../selftests/bpf/progs/stack_arg_precision.c | 3 +- .../selftests/bpf/progs/verifier_stack_arg.c | 3 +- .../selftests/bpf/progs/verifier_stack_arg_order.c | 3 +- 10 files changed, 95 insertions(+), 10 deletions(-) --- base-commit: d114bb98936770c501c958bf2bc5fb6b7c0bad7b change-id: 20260728-bpf-riscv-stack-args-6350d066a1e9 Best regards, -- Feng Jiang <[email protected]>
