From c0316386fecd0633b08ed87fb707eb42dc900dfe Mon Sep 17 00:00:00 2001 From: Chen Pei Date: Mon, 28 Sep 2026 15:18:42 +0800 Subject: [PATCH 1/4] bpf, riscv: Add support for indirect jumps MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Implement JIT support for the indirect jump instruction (BPF_JMP | BPF_JA | BPF_X), a.k.a. gotox, which lets a BPF program jump through a BPF_MAP_TYPE_INSN_ARRAY jump table. Emit "jalr zero, rd, 0" and hand the xlated to jitted offsets to bpf_prog_update_insn_ptrs(), which is what fills in the jump table entries; without that call the load fails with -EFAULT in bpf_insn_array_ready(). ctx->offset[] holds the offset of the insn *following* insn i, as bpf_prog_fill_jited_linfo() expects, so it is shifted by one and offset[0] comes from the prologue length. build_body() now records both halves of a multi-insn record, so no slot keeps a fabricated offset. Only the RV64 JIT is covered; RV32 keeps failing to load as before. Signed-off-by: Chen Pei Signed-off-by: Alexei Starovoitov Reviewed-by: Björn Töpel Reviewed-by: Pu Lehui Acked-by: Björn Töpel Link: https://patch.msgid.link/20260928071845.2432-2-cp0613@linux.alibaba.com --- arch/riscv/net/bpf_jit_comp64.c | 5 +++++ arch/riscv/net/bpf_jit_core.c | 16 ++++++++++++++-- 2 files changed, 19 insertions(+), 2 deletions(-) diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index 016994aef94d..788fcc21fd5b 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -1719,6 +1719,11 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx, emit_zextw(rd, rd, ctx); break; + /* JUMP reg */ + case BPF_JMP | BPF_JA | BPF_X: + emit_jalr(RV_REG_ZERO, rd, 0, ctx); + break; + /* JUMP off */ case BPF_JMP | BPF_JA: case BPF_JMP32 | BPF_JA: diff --git a/arch/riscv/net/bpf_jit_core.c b/arch/riscv/net/bpf_jit_core.c index 470a6ace5662..5265dd5bd39e 100644 --- a/arch/riscv/net/bpf_jit_core.c +++ b/arch/riscv/net/bpf_jit_core.c @@ -26,10 +26,13 @@ static int build_body(struct rv_jit_context *ctx, bool extra_pass, int *offset) int ret; ret = bpf_jit_emit_insn(insn, ctx, extra_pass); - if (ret > 0) - i++; /* skip the next instruction */ if (offset) offset[i] = ctx->ninsns; + if (ret > 0) { + i++; /* skip the next instruction */ + if (offset) + offset[i] = ctx->ninsns; + } if (ret < 0) return ret; } @@ -176,6 +179,15 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_verifier_env *env, struct bpf_pr for (i = 0; i < prog->len; i++) ctx->offset[i] = ninsns_rvoff(ctx->offset[i]); bpf_prog_fill_jited_linfo(prog, ctx->offset); + + /* + * bpf_prog_update_insn_ptrs() wants the start of each insn, so + * shift ctx->offset[] by one and get insn 0 from the prologue. + */ + for (i = prog->len - 1; i > 0; i--) + ctx->offset[i] = ctx->offset[i - 1]; + ctx->offset[0] = ninsns_rvoff(ctx->prologue_len); + bpf_prog_update_insn_ptrs(prog, ctx->offset, jit_data->ro_image); out_offset: kvfree(ctx->offset); kfree(jit_data); From 5f750ad6d67508d83d0aadaae674f4d768814c12 Mon Sep 17 00:00:00 2001 From: Chen Pei Date: Mon, 28 Sep 2026 15:18:43 +0800 Subject: [PATCH 2/4] selftests/bpf: Enable gotox tests for riscv64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The riscv64 JIT now supports the gotox instruction and jump tables, so run the tests in verifier_gotox.c on riscv64 too, mirroring what was done for arm64 and powerpc. The guard is 64-bit only because the RV32 JIT does not implement gotox. Signed-off-by: Chen Pei Signed-off-by: Alexei Starovoitov Reviewed-by: Björn Töpel Acked-by: Björn Töpel Link: https://patch.msgid.link/20260928071845.2432-3-cp0613@linux.alibaba.com --- tools/testing/selftests/bpf/progs/verifier_gotox.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/progs/verifier_gotox.c b/tools/testing/selftests/bpf/progs/verifier_gotox.c index 84302a122ccf..3d1ff7078a72 100644 --- a/tools/testing/selftests/bpf/progs/verifier_gotox.c +++ b/tools/testing/selftests/bpf/progs/verifier_gotox.c @@ -6,7 +6,9 @@ #include "bpf_misc.h" #include "../../../include/linux/filter.h" -#if defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_powerpc) +#if defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || \ + defined(__TARGET_ARCH_powerpc) || \ + (defined(__TARGET_ARCH_riscv) && __riscv_xlen == 64) #define DEFINE_SIMPLE_JUMP_TABLE_PROG(NAME, SRC_REG, OFF, IMM, OUTCOME) \ \ @@ -586,6 +588,6 @@ nop_%=: \ : __clobber_all); } -#endif /* __TARGET_ARCH_x86 || __TARGET_ARCH_arm64 || __TARGET_ARCH_powerpc*/ +#endif /* gotox: x86, arm64, powerpc, riscv64 */ char _license[] SEC("license") = "GPL"; From 6ce75af4f59eb7065859cba7f6a563dfb1b7ab75 Mon Sep 17 00:00:00 2001 From: Chen Pei Date: Mon, 28 Sep 2026 15:18:44 +0800 Subject: [PATCH 3/4] selftests/bpf: Enable gotox liveness test for riscv64 The riscv64 JIT now supports gotox, so enable the gotox liveness test in compute_live_registers.c on riscv64 as well. The guard is 64-bit only because the RV32 JIT does not implement gotox. Signed-off-by: Chen Pei Signed-off-by: Alexei Starovoitov Link: https://patch.msgid.link/20260928071845.2432-4-cp0613@linux.alibaba.com --- tools/testing/selftests/bpf/progs/compute_live_registers.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/progs/compute_live_registers.c b/tools/testing/selftests/bpf/progs/compute_live_registers.c index b0aaf5961ac9..1ff24bbc7beb 100644 --- a/tools/testing/selftests/bpf/progs/compute_live_registers.c +++ b/tools/testing/selftests/bpf/progs/compute_live_registers.c @@ -496,7 +496,8 @@ __naked void subprog_ret_reg_pair(void) ::: __clobber_all); } -#if defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) +#if defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || \ + (defined(__TARGET_ARCH_riscv) && __riscv_xlen == 64) SEC("socket") __log_level(2) @@ -535,7 +536,7 @@ void gotox(void) : __clobber_all); } -#endif /* __TARGET_ARCH_x86 || __TARGET_ARCH_arm64 */ +#endif /* gotox: x86, arm64, riscv64 */ /* to retain debug info for BTF generation */ void kfunc_root(void) From eec2444d9b9d8cd2bf5e7f54d830325c9b2a1c7d Mon Sep 17 00:00:00 2001 From: Chen Pei Date: Mon, 28 Sep 2026 15:18:45 +0800 Subject: [PATCH 4/4] selftests/bpf: Enable instruction array test for riscv64 As the riscv64 JIT now supports instruction array (gotox jump tables), enable the corresponding bpf selftest for riscv64. The guard is 64-bit only because the RV32 JIT does not implement gotox. Signed-off-by: Chen Pei Signed-off-by: Alexei Starovoitov Link: https://patch.msgid.link/20260928071845.2432-5-cp0613@linux.alibaba.com --- tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c b/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c index bfedeed24ac5..4ffe4fe6b78e 100644 --- a/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c +++ b/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c @@ -4,7 +4,8 @@ #include #include -#if defined(__x86_64__) || defined(__powerpc__) || defined(__aarch64__) +#if defined(__x86_64__) || defined(__powerpc__) || defined(__aarch64__) || \ + (defined(__riscv) && __riscv_xlen == 64) static int map_create(__u32 map_type, __u32 max_entries) { const char *map_name = "insn_array";