From: Jakub Kicinski <jakub.kicinski@netronome.com>
To: Jiong Wang <jiong.wang@netronome.com>
Cc: alexei.starovoitov@gmail.com, daniel@iogearbox.net,
bpf@vger.kernel.org, netdev@vger.kernel.org,
oss-drivers@netronome.com
Subject: Re: [PATCH/RFC v2 bpf-next 06/19] bpf: mark lo32 writes that should be zero extended into hi32
Date: Wed, 10 Apr 2019 20:13:12 -0700 [thread overview]
Message-ID: <20190410201302.4e67d48f@cakuba.netronome.com> (raw)
In-Reply-To: <1554925833-7333-7-git-send-email-jiong.wang@netronome.com>
On Wed, 10 Apr 2019 20:50:20 +0100, Jiong Wang wrote:
> @@ -2169,6 +2188,12 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
> value_regno);
> if (reg_type_may_be_null(reg_type))
> regs[value_regno].id = ++env->id_gen;
> + /* A load of ctx field could have different
> + * actual load size with the one encoded in the
> + * insn. When the dst is PTR, it is for sure not
> + * a sub-register.
> + */
> + regs[value_regno].subreg_def = DEF_NOT_SUBREG;
Can't the rewrite generate a 32bit load? E.g. reading skb->len will be
LDX | W, we still gotta clear the top bits in that case, no?
I can't find the explanation of this case with a quick scan of the code
and cover letter..
> }
> regs[value_regno].type = reg_type;
> }
next prev parent reply other threads:[~2019-04-11 3:13 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-10 19:50 [PATCH/RFC v2 bpf-next 00/19] bpf: eliminate zero extensions for sub-register writes Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 01/19] bpf: refactor propagate_liveness to eliminate duplicated for loop Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 02/19] bpf: refactor propagate_liveness to eliminate code redundance Jiong Wang
2019-04-11 2:39 ` [oss-drivers] " Jakub Kicinski
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 03/19] bpf: factor out reg and stack slot propagation into "propagate_liveness_reg" Jiong Wang
2019-04-11 2:39 ` [oss-drivers] " Jakub Kicinski
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 04/19] bpf: refactor "check_reg_arg" to eliminate code redundancy Jiong Wang
2019-04-11 2:40 ` Jakub Kicinski
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 05/19] bpf: split read liveness into REG_LIVE_READ64 and REG_LIVE_READ32 Jiong Wang
2019-04-11 2:52 ` Jakub Kicinski
2019-04-11 6:13 ` Jiong Wang
2019-04-11 16:44 ` [oss-drivers] " Jakub Kicinski
2019-04-11 16:53 ` Jiong Wang
2019-04-12 16:14 ` Jiong Wang
2019-04-11 17:22 ` Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 06/19] bpf: mark lo32 writes that should be zero extended into hi32 Jiong Wang
2019-04-11 3:13 ` Jakub Kicinski [this message]
2019-04-11 6:02 ` Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 07/19] bpf: reduce false alarm by refining helper call arg types Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 08/19] bpf: insert explicit zero extension insn when hardware doesn't do it implicitly Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 09/19] bpf: introduce new bpf prog load flags "BPF_F_TEST_RND_HI32" Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 10/19] bpf: randomize high 32-bit when BPF_F_TEST_RND_HI32 is set Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 11/19] libbpf: new global variable "libbpf_test_mode" Jiong Wang
2019-04-11 3:19 ` Jakub Kicinski
2019-04-11 14:32 ` Jiong Wang
2019-04-11 21:49 ` Jiong Wang
2019-04-12 22:08 ` Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 12/19] selftests: enable hi32 randomization for "test_progs" and "test_verifier" Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 13/19] arm: bpf: eliminate zero extension code-gen Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 14/19] powerpc: " Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 15/19] s390: " Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 16/19] sparc: " Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 17/19] x32: " Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 18/19] riscv: " Jiong Wang
2019-04-10 19:50 ` [PATCH/RFC v2 bpf-next 19/19] nfp: " Jiong Wang
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