From: Mikael Pettersson <mikpe@it.uu.se>
To: Nathan Lynch <ntl@pobox.com>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org,
Paul Mackerras <paulus@samba.org>,
Roland McGrath <roland@redhat.com>
Subject: Re: [PATCH 1/2] elf loader support for auxvec base platform string
Date: Fri, 4 Jul 2008 04:35:54 +0200 [thread overview]
Message-ID: <18541.35978.437115.957054@harpo.it.uu.se> (raw)
In-Reply-To: <20080703234140.GC9594@localdomain>
Nathan Lynch writes:
> Some IBM POWER-based platforms have the ability to run in a
> mode which mostly appears to the OS as a different processor from the
> actual hardware. For example, a Power6 system may appear to be a
> Power5+, which makes the AT_PLATFORM value "power5+".
>
> However, some applications (virtual machines, optimized libraries) can
> benefit from knowledge of the underlying CPU model. A new aux vector
> entry, AT_BASE_PLATFORM, will denote the actual hardware. For
> example, on a Power6 system in Power5+ compatibility mode, AT_PLATFORM
> will be "power5+" and AT_BASE_PLATFORM will be "power6".
Why on earth would you ever want AT_PLATFORM to differ from AT_BASE_PLATFORM?
In cases that matter you admit that AT_BASE_PLATFORM takes precedence,
so why involve a fake lame not-quite-the-platform in the first place?
Workaround for buggy software?
next prev parent reply other threads:[~2008-07-04 2:37 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-03 23:41 Nathan Lynch
2008-07-04 2:19 ` Roland McGrath
2008-07-07 5:48 ` Benjamin Herrenschmidt
2008-07-07 6:18 ` Roland McGrath
2008-07-07 6:23 ` Benjamin Herrenschmidt
2008-07-07 6:35 ` Roland McGrath
2008-07-07 6:48 ` Benjamin Herrenschmidt
2008-07-07 7:49 ` Andreas Schwab
2008-07-07 9:31 ` Roland McGrath
2008-07-07 10:01 ` Andreas Schwab
2008-07-07 22:56 ` Benjamin Herrenschmidt
2008-07-08 0:31 ` Roland McGrath
2008-07-08 0:48 ` Benjamin Herrenschmidt
2008-07-08 18:35 ` Steven Munroe
2008-07-07 16:16 ` Nathan Lynch
2008-07-07 22:17 ` Nathan Lynch
2008-07-07 23:00 ` Benjamin Herrenschmidt
2008-07-04 2:35 ` Mikael Pettersson [this message]
2008-07-07 15:55 ` Nathan Lynch
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