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From: "David S. Miller" <davem@davemloft.net>
To: sparclinux@vger.kernel.org
Subject: Re: PAGE_SIZE and native vs. emulated 32-bit SPARC ABI
Date: Tue, 04 Jan 2005 18:46:56 +0000	[thread overview]
Message-ID: <20050104104656.08e4564c.davem@davemloft.net> (raw)
In-Reply-To: <20041230110707.GC29332@holomorphy.com>

On Thu, 30 Dec 2004 03:07:07 -0800
William Lee Irwin III <wli@holomorphy.com> wrote:

> It seems that most/all 32-bit SPARC programs are written and compiled
> for emulated 32-bit on sun4u, which has an 8KB PAGE_SIZE, and returns
> 8KB for getpagesize(). This is unfortunately causing spectacular
> failures on some of my favorite regression tests for memory management,
> which are interpreters using memory protection-based garbage collectors.

The Sparc ABI states that one may make no assumptions about
the PAGE_SIZE in any way.  That's why 32-bit Sparc ELF binaries
compiled before sun4u even existed can execute properly on 8KB
PAGE_SIZE systems.

Not using getpagesize() is a pretty serious programming error.

There are even facilities in the Sparc ELF specification that allow
the binaries to work just fine for up to a 64KB page size.  A long
time ago, Kanoj Sarcar played around with changing the default PAGE_SIZE
of sparc64 to be 64K and all 32-bit binaries worked just fine.

  parent reply	other threads:[~2005-01-04 18:46 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-12-30 11:07 PAGE_SIZE and native vs. emulated 32-bit SPARC ABI William Lee Irwin III
2004-12-30 11:50 ` C.Newport
2004-12-30 12:13 ` William Lee Irwin III
2005-01-04 18:46 ` David S. Miller [this message]
2005-01-04 18:54 ` William Lee Irwin III

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