Re: [PATCH v4 bpf-next 15/15] nfp: bpf: eliminate zero extension code-gen

From: kbuild test robot <lkp@intel.com>
To: Jiong Wang <jiong.wang@netronome.com>
Cc: kbuild-all@01.org, alexei.starovoitov@gmail.com,
	daniel@iogearbox.net, bpf@vger.kernel.org,
	netdev@vger.kernel.org, oss-drivers@netronome.com,
	Jiong Wang <jiong.wang@netronome.com>
Subject: Re: [PATCH v4 bpf-next 15/15] nfp: bpf: eliminate zero extension code-gen
Date: Thu, 25 Apr 2019 00:31:01 +0800	[thread overview]
Message-ID: <201904250050.Z0Q6veLQ%lkp@intel.com> (raw)
In-Reply-To: <1555349185-12508-16-git-send-email-jiong.wang@netronome.com>

Hi Jiong,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/0day-ci/linux/commits/Jiong-Wang/bpf-eliminate-zero-extensions-for-sub-register-writes/20190416-191711
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
reproduce:
        # apt-get install sparse
        make ARCH=x86_64 allmodconfig
        make C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

sparse warnings: (new ones prefixed by >>)

>> drivers/net/ethernet/netronome/nfp/bpf/jit.c:2654:34: sparse: sparse: incorrect type in argument 3 (different base types) @@    expected unsigned char [usertype] dst @@    got resunsigned char [usertype] dst @@
>> drivers/net/ethernet/netronome/nfp/bpf/jit.c:2654:34: sparse:    expected unsigned char [usertype] dst
>> drivers/net/ethernet/netronome/nfp/bpf/jit.c:2654:34: sparse:    got restricted swreg [usertype] dst
   drivers/net/ethernet/netronome/nfp/bpf/jit.c:2680:34: sparse: sparse: incorrect type in argument 3 (different base types) @@    expected unsigned char [usertype] dst @@    got resunsigned char [usertype] dst @@
   drivers/net/ethernet/netronome/nfp/bpf/jit.c:2680:34: sparse:    expected unsigned char [usertype] dst
   drivers/net/ethernet/netronome/nfp/bpf/jit.c:2680:34: sparse:    got restricted swreg [usertype] dst

vim +2654 drivers/net/ethernet/netronome/nfp/bpf/jit.c

  2627	
  2628	static int mem_ldx_skb(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
  2629			       u8 size)
  2630	{
  2631		swreg dst = reg_both(meta->insn.dst_reg * 2);
  2632	
  2633		switch (meta->insn.off) {
  2634		case offsetof(struct __sk_buff, len):
  2635			if (size != FIELD_SIZEOF(struct __sk_buff, len))
  2636				return -EOPNOTSUPP;
  2637			wrp_mov(nfp_prog, dst, plen_reg(nfp_prog));
  2638			break;
  2639		case offsetof(struct __sk_buff, data):
  2640			if (size != FIELD_SIZEOF(struct __sk_buff, data))
  2641				return -EOPNOTSUPP;
  2642			wrp_mov(nfp_prog, dst, pptr_reg(nfp_prog));
  2643			break;
  2644		case offsetof(struct __sk_buff, data_end):
  2645			if (size != FIELD_SIZEOF(struct __sk_buff, data_end))
  2646				return -EOPNOTSUPP;
  2647			emit_alu(nfp_prog, dst,
  2648				 plen_reg(nfp_prog), ALU_OP_ADD, pptr_reg(nfp_prog));
  2649			break;
  2650		default:
  2651			return -EOPNOTSUPP;
  2652		}
  2653	
> 2654		wrp_zext(nfp_prog, meta, dst);
  2655	
  2656		return 0;
  2657	}
  2658	

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