On Sun, Mar 16, 2025 at 7:41 PM Vincent Li <vincent.mc.li@xxxxxxxxx> wrote:
>
> On Sun, Mar 16, 2025 at 6:58 PM Hengqi Chen <hengqi.chen@xxxxxxxxx> wrote:
> >
> > Vincent reported that running XDP synproxy program on LoongArch
> > results in the following error:
> > JIT doesn't support bpf-to-bpf calls
> > With dmesg:
> > multi-func JIT bug 1391 != 1390
> >
> > The root cause is that verifier will refill the imm with the
> > correct addresses of bpf_calls for BPF_PSEUDO_FUNC instructions
> > and then run the last pass of JIT. So we generate different JIT
> > code for the same instruction in two passes (one for placeholder
> > and one for real address). Let's use move_addr() instead.
> >
> > See commit 64f50f657572 ("LoongArch, bpf: Use 4 instructions for
> > function address in JIT") for a similar fix.
> >
> > Fixes: 69c087ba6225 ("bpf: Add bpf_for_each_map_elem() helper")
> > Fixes: bb035ef0cc91 ("LoongArch: BPF: Support mixing bpf2bpf and tailcalls")
> > Reported-by: Vincent Li <vincent.mc.li@xxxxxxxxx>
> > Closes: https://lore.kernel.org/loongarch/CAK3+h2yfM9FTNiXvEQBkvtuoJrvzmN4c_NZsFXqEk4Cj1tsBNA@xxxxxxxxxxxxxx/T/#u
> > Signed-off-by: Hengqi Chen <hengqi.chen@xxxxxxxxx>
> > ---
> > arch/loongarch/net/bpf_jit.c | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c
> > index ea357a3edc09..b25b0bb43428 100644
> > --- a/arch/loongarch/net/bpf_jit.c
> > +++ b/arch/loongarch/net/bpf_jit.c
> > @@ -930,7 +930,10 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
> > {
> > const u64 imm64 = (u64)(insn + 1)->imm << 32 | (u32)insn->imm;
> >
> > - move_imm(ctx, dst, imm64, is32);
> > + if (bpf_pseudo_func(insn))
> > + move_addr(ctx, dst, imm64);
> > + else
> > + move_imm(ctx, dst, imm64, is32);
> > return 1;
> > }
> >
> > --
> > 2.43.5
> >
>
> Thanks Hengqi for the quick fix! tested and verified working now.
>
> [root@fedora xdp-tools]# uname -a
> Linux fedora 6.14.0-rc5 #2 SMP PREEMPT_DYNAMIC Sun Mar 16 17:16:21 PDT
> 2025 loongarch64 GNU/Linux
>
> [root@fedora xdp-tools]# ./xdp-loader/xdp-loader load -vvv lo -m skb
> -P 80 -p /sys/fs/bpf/xdp-synproxy-tailcall -n synproxy_tailcall
> ./xdp-synproxy-tailcall/xdp_synproxy_tailcall.bpf.o
> Current rlimit 8388608 already >= minimum 1048576
> Loading 1 files on interface 'lo'.
> libbpf: loading object from
> ./xdp-synproxy-tailcall/xdp_synproxy_tailcall.bpf.o
> ...
> libbpf: map 'tail_call_tbl': created successfully, fd=4
> libbpf: pinned map '/sys/fs/bpf/xdp-synproxy-tailcall/tail_call_tbl'
> libbpf: found no pinned map to reuse at
> '/sys/fs/bpf/xdp-synproxy-tailcall/values'
> libbpf: map 'values': created successfully, fd=5
> libbpf: pinned map '/sys/fs/bpf/xdp-synproxy-tailcall/values'
> libbpf: found no pinned map to reuse at
> '/sys/fs/bpf/xdp-synproxy-tailcall/allowed_ports'
> libbpf: map 'allowed_ports': created successfully, fd=6
> libbpf: pinned map '/sys/fs/bpf/xdp-synproxy-tailcall/allowed_ports'
> libbpf: map 'xdp_synp.rodata': created successfully, fd=7
> libbpf: map 'tail_call_tbl': slot [0] set to prog 'syncookie_xdp' fd=65
> libxdp: Loaded XDP program synproxy_tailcall, got fd 66
> libxdp: Duplicated fd 66 to 3 for prog synproxy_tailcall
> libxdp: Replacing XDP fd -1 with 3 on ifindex 1
>
> [root@fedora xdp-tools]# bpftool prog
> ...
> 55: xdp name syncookie_xdp tag 1426f5e6593da050 gpl
> loaded_at 2025-03-16T19:38:49-0700 uid 0
> xlated 8392B jited 6412B memlock 16384B map_ids 11,10,12
> btf_id 75
>
> 56: xdp name synproxy_tailcall tag 0433e599459b925f gpl
> loaded_at 2025-03-16T19:38:49-0700 uid 0
> xlated 192B jited 328B memlock 16384B map_ids 9,12
> btf_id 75
Sorry missed the Tested-by, you can add:
Tested-by: Vincent Li <vincent.mc.li@xxxxxxxxx>
