[PATCH bpf-next 5/7] bpf, arm64: Support 32-bit offset jmp instruction

[Xu Kuohai]

From: Xu Kuohai <xukuohai at huawei.com>

Add support for 32-bit offset jmp instructions. Given the arm64
direct jump range is +-128MB, which is large enough for BPF prog,
jumps beyond this range are not supported.

Signed-off-by: Xu Kuohai <xukuohai at huawei.com>
---
 arch/arm64/net/bpf_jit_comp.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 1d35acb880dc..924b8ef2e46a 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -982,7 +982,11 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
 
 	/* JUMP off */
 	case BPF_JMP | BPF_JA:
-		jmp_offset = bpf2a64_offset(i, off, ctx);
+	case BPF_JMP32 | BPF_JA:
+		if (BPF_CLASS(code) == BPF_JMP)
+			jmp_offset = bpf2a64_offset(i, off, ctx);
+		else
+			jmp_offset = bpf2a64_offset(i, imm, ctx);
 		check_imm26(jmp_offset);
 		emit(A64_B(jmp_offset), ctx);
 		break;
-- 
2.30.2