linux-kernel - Re: [Patch 0/1] HW-BKPT: Allow per-cpu kernel-space Hardware Breakpoint requests

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: <20090826091642.GB7743@elte.hu>
Date:	Wed, 26 Aug 2009 11:16:42 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Frederic Weisbecker <fweisbec@...il.com>
Cc:	"K.Prasad" <prasad@...ux.vnet.ibm.com>,
	Peter Zijlstra <peterz@...radead.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Lai Jiangshan <laijs@...fujitsu.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>,
	Alan Stern <stern@...land.harvard.edu>
Subject: Re: [Patch 0/1] HW-BKPT: Allow per-cpu kernel-space Hardware
	Breakpoint requests


* Frederic Weisbecker <fweisbec@...il.com> wrote:

> On Fri, Aug 21, 2009 at 04:28:11PM +0200, Ingo Molnar wrote:
> > 
> > * K.Prasad <prasad@...ux.vnet.ibm.com> wrote:
> > 
> > > > Providing those would let us build a pmu struct on top of this 
> > > > high level API, hopefully.
> > 
> > Note that there's a PMU struct already in 
> > arch/x86/kernel/cpu/perf_counter.c. Could debug-register ops be 
> > tacked on to it?
> 
> No, we don't need to build an arch level pmu since the BP api 
> already handles the arch abstraction (or well, it is planned to).
> 
> Instead, what we need is a core pmu that relies on the BP api. 
> Such pmu will be allocated dynamically while creating a hardware 
> breakpoint counter.

i'm not convinced at all we need all that layering of 
perfcounters->pmu->BP. Why not add BP support to the PMU abstraction 
and be done with it?

That way we get hardware breakpoints via 'pinned, exclusive, per cpu 
hw-breakpoint counters' for example and kernel/hw-breakpoint.c can 
go away altogether.

kernel/perf_counter.c already handles scheduling, conflict 
resolution, enumeration, syscall exposure and more.

Hm?

	Ingo
--
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/