[PATCH bpf-next v3 0/4] bpf, riscv: Add support for indirect jumps

[Pu Lehui]

On 2026/9/28 15:18, Chen Pei wrote:
> The indirect jump instruction (BPF_JMP | BPF_JA | BPF_X, "gotox") and the
> BPF_MAP_TYPE_INSN_ARRAY jump tables it consumes are core features: the
> verifier accepts them on every architecture, and the x86-64, arm64 and
> powerpc JITs implement them. On riscv64 a program using gotox passes
> verification and then fails to load, because the JIT does not know the
> opcode and CONFIG_BPF_JIT_ALWAYS_ON leaves no interpreter to fall back
> onto.
> 
> This series adds the riscv64 support and turns the existing selftests on
> for that architecture.
> 
> Patch 1 emits "jalr zero, rd, 0" for gotox and publishes the xlated to
> jitted offsets through bpf_prog_update_insn_ptrs(), which is what fills
> in the jump table addresses. Patches 2 to 4 widen the arch guards in
> verifier_gotox.c, compute_live_registers.c and bpf_insn_array.c to
> riscv64, the same way the other architectures were enabled.
> 
> Changes since v2:
> - Pick up Pu Lehui's Reviewed-by on patch 1.
> - Enable two more gotox test files for riscv64: compute_live_registers.c
>    and bpf_insn_array.c.
> 
> Changes since v1:
> - Rebased onto bpf-next.
> - Patch 1: reword the code comment to say "shift ctx->offset[] by one".
> - Patch 2: collapse the multi-line #endif marker to a single line.
> - Added Reviewed-by/Acked-by from Björn Töpel.
> 
> Testing
> =======
> 
> Environment: QEMU virt rv64, with CONFIG_BPF_JIT=y,
> CONFIG_BPF_JIT_ALWAYS_ON=y, CONFIG_DEBUG_INFO_BTF=y; selftests
> cross-built with clang 23.
> 
> - test_progs -t verifier_gotox: 33/33 subtests pass.
> - test_progs -t bpf_insn_array: 20/20 subtests pass.
> - test_progs -t compute_live_registers: 20/20 subtests pass, including
>    the gotox liveness subtest.
> - test_progs-cpuv4 -t bpf_gotox: 14/14 subtests pass.
> 
> Chen Pei (4):
>    bpf, riscv: Add support for indirect jumps
>    selftests/bpf: Enable gotox tests for riscv64
>    selftests/bpf: Enable gotox liveness test for riscv64
>    selftests/bpf: Enable instruction array test for riscv64
> 
>   arch/riscv/net/bpf_jit_comp64.c                  |  5 +++++
>   arch/riscv/net/bpf_jit_core.c                    | 16 ++++++++++++++--
>   .../selftests/bpf/prog_tests/bpf_insn_array.c    |  3 ++-
>   .../selftests/bpf/progs/compute_live_registers.c |  5 +++--
>   .../testing/selftests/bpf/progs/verifier_gotox.c |  6 ++++--
>   5 files changed, 28 insertions(+), 7 deletions(-)
> 

For this series:

Tested-by: Pu Lehui <pulehui at huawei.com>