in net/bpf_jit.h [806:814]
static inline void emit_jalr(u8 rd, u8 rs, s32 imm, struct rv_jit_context *ctx)
{
if (rvc_enabled() && rd == RV_REG_RA && rs && !imm)
emitc(rvc_jalr(rs), ctx);
else if (rvc_enabled() && !rd && rs && !imm)
emitc(rvc_jr(rs), ctx);
else
emit(rv_jalr(rd, rs, imm), ctx);
}