linux-kernel - Re: [PATCH 14/29] memstick: remove the memstick_set_rw

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: <1288058912.4024.137.camel@maxim-laptop>
Date:	Tue, 26 Oct 2010 04:08:32 +0200
From:	Maxim Levitsky <maximlevitsky@...il.com>
To:	Alex Dubov <oakad@...oo.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 14/29] memstick: remove the memstick_set_rw_addr

On Mon, 2010-10-25 at 08:55 -0700, Alex Dubov wrote:
> 
> --- On Fri, 22/10/10, Maxim Levitsky <maximlevitsky@...il.com> wrote:
> 
> > From: Maxim Levitsky <maximlevitsky@...il.com>
> > Subject: [PATCH 14/29] memstick: remove the memstick_set_rw_addr
> > To: "Alex Dubov" <oakad@...oo.com>
> > Cc: "Andrew Morton" <akpm@...ux-foundation.org>, "LKML" <linux-kernel@...r.kernel.org>, "Maxim Levitsky" <maximlevitsky@...il.com>
> > Received: Friday, 22 October, 2010, 4:53 PM
> > Remove this function, what was
> > last user that did send the MS_TPC_SET_RW_REG_ADRS
> > directly.
> > 
> > Just invalidate the register window, and next register
> > read/write will send that tpc automaticly.
> > 
> > Signed-off-by: Maxim Levitsky <maximlevitsky@...il.com>
> > ---
> 
> How is an obscure invalidate_reg_window function is any better than
> explicit set_rw_addr? Total number of calls to either of them is exactly
> the same.
Nope.
I just set the reg window where it should be: in register read/write
functions.
Here we tampered with register window by using another card structure,
so we invalidate it. Simple.
The point is that I send the register window update just before register
read/write, and optionaly skip that if cached version matches the one I
need.


> 
> Sony state machine diagrams suggest that doing a precise set_rw_addr when
> necessary is a good thing. 
And that exactly what I am doing.
I am setting that window just before a register read/write.


> The feature was originally conceived because
> Sony intended to manufacture MSIO and hybrid devices, which might have very
> large number of registers (hundreds). It was also supposed to help with
> backward compatibility of devices, as well as with DRM functionality
> 
> We know, at this point of time, that Sony is sort of loosing the format
> war, so MSIO devices these days are very hard to come by. However, some
> hybrid (Transfer Jet) and DRM-secured devices still exist and it is wise
> to retain functionality which can help to operate those (I don't have full
> details on their operation, but it doesn't mean we should forget them
> outright).


Best regards,
	Maxim Levitsky


--
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/