linux-kernel - Re: [PATCH 1/2] tools, perf: Add a precise event qualifier v2

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: <20130912173617.GI18242@two.firstfloor.org>
Date:	Thu, 12 Sep 2013 19:36:17 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	Andi Kleen <andi@...stfloor.org>, Vince Weaver <vince@...ter.net>,
	Andi Kleen <ak@...ux.intel.com>, acme@...radead.org,
	linux-kernel@...r.kernel.org,
	Peter Zijlstra <peterz@...radead.org>,
	Stephane Eranian <eranian@...gle.com>,
	torvalds@...ux-foundation.org, trinity@...r.kernel.org,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Thomas Gleixner <tglx@...utronix.de>,
	Frédéric Weisbecker <fweisbec@...il.com>,
	Jiri Olsa <jolsa@...hat.com>, Namhyung Kim <namhyung@...il.com>
Subject: Re: [PATCH 1/2] tools, perf: Add a precise event qualifier v2

> Your feature to export 'precise' requirements on events looks useful to 
> me. We could implement it not by special casing it implicitly but by 
> saying that if ../format/precise contains something like:
> 
>    attr:240-241
> 
> then that's a natural extension of the config:X-Y format and should be 
> interpreted to mean mean 2 bits in the perf attr field. I.e. we could go 
> beyond the config bitfield.
> 
> Basically the whole perf_event_attr can be thought of as a 'giant 
> bitfield', in which we can specify values to export an enumerated list of 
> events from the kernel to tooling.
> 
> (Using attr:X-Y the config and config1 variants can be expressed as well, 
> as the config fields are inside the attr structure.)
> 
> The positions within the perf_attr are an ABI, so this would work pretty 
> well.

Wouldn't we need different bits for each architecture then?
32bit/64bit, some archs with weird alignment rules, maybe different for
BE/LE too?

Ok I suppose it could be somehow auto generated in asm-offsets.c,
although I'm not sure how to get a bitfield offset there.

-Andi


-- 
ak@...ux.intel.com -- Speaking for myself only.
--
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/