linux-kernel - Re: llvm bpf debug info. Re: [RFC PATCH v4 3/3] bpf: Introduce function for outputing data to perf event

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <55B951A0.5040607@plumgrid.com>
Date:	Wed, 29 Jul 2015 15:20:16 -0700
From:	Alexei Starovoitov <ast@...mgrid.com>
To:	pi3orama <pi3orama@....com>
Cc:	He Kuang <hekuang@...wei.com>, "Wangnan (F)" <wangnan0@...wei.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: llvm bpf debug info. Re: [RFC PATCH v4 3/3] bpf: Introduce
 function for outputing data to perf event

On 7/29/15 1:00 PM, pi3orama wrote:
> I was wondering if you could give us a hint on adding BPF specific builtins?
>
> Doesn't like other machines, currently there's no Builtins.def for BPF to hold
> builtins for that specific target. If we start creating such builtins, we can bring
> more there. One builtins I want to see should be __builtin_bpf_strcmp(char*, char*),
> with that we can filter events base on name of a task. What I really need is filtering
> events based on comm of the main thread, which should be useful on Android
> since in Android name of working threads are always something like "Binder_?",
> only the main threads names are meaningful. But let's work on strcmp first.

Currently there are 4 of them in IntrinsicsBPF.td
but I don't see how strcmp can work with current no-loops restriction.
As an alternative to filter binder threads you can use
memcmp(ptr, "Binder_", 6) since it will get unrolled fully.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/