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Date:      Mon, 17 Mar 2003 00:58:44 -0500 (EST)
From:      Robert Watson <rwatson@FreeBSD.org>
To:        arch@FreeBSD.org
Subject:   sizeof(void *)!=sizeof(vm_paddr_t)
Message-ID:  <Pine.NEB.3.96L.1030317005448.57214A-100000@fledge.watson.org>

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I just committed a new column to our increasingly complicated driver
status table on the web site.  This column is intended to capture whether
or not drivers are able to handle (both compile and run properly in) an
environment where the assumption that a physical memory address can be
stored in a variable of a pointer type.  Intel PAE support will operate
only with drivers that meet this assumption.  If driver developers could
review the table at

  http://www.FreeBSD.org/projects/busdma/

to make sure their driver is accurately characterized from the perspective
of the current criteria: busdma, INTR_MPSAFE, SMPng locked, and p!=a
safety.  In addition, if your driver is not safe on one or more of these
counts, fixing it prior to 5.1-RELEASE would be a very good idea.  Drivers
not adapted for these requirements will perform less well than drivers
that are adapted, run on few hardware architectures, and may not run with
large memory systems.  I've set the "default" for p!=a safety to "New",
but I suspect a moderate number of drivers are already safe from this
regard (including syscons, ata, ...)

Thanks,

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert@fledge.watson.org      Network Associates Laboratories

---------- Forwarded message ----------
Date: Sun, 16 Mar 2003 21:44:30 -0800 (PST)
From: Robert Watson <rwatson@FreeBSD.org>
To: doc-committers@FreeBSD.org, cvs-doc@FreeBSD.org, cvs-all@FreeBSD.org
Subject: cvs commit: www/en/projects/busdma index.sgml

rwatson     2003/03/16 21:44:30 PST

  FreeBSD doc repository

  Modified files:
    en/projects/busdma   index.sgml 
  Log:
  Add a new driver status column to indicate whether the driver can
  safely handle sizeof(void *) != sizeof(vm_paddr_t) or !=
  sizeof(bus_addr_t).  In order for drivers to be supported with PAE,
  they must be able to handle this, including avoiding casting of
  physical addresses to pointers for printfs, pointer arithmetic,
  etc.
  
  Thought reasonable by:  jake
  
  Revision  Changes    Path
  1.50      +88 -0     www/en/projects/busdma/index.sgml


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