Re: [PATCH RFC] function probe_roms accessing improper addresses

2012-10-23 Thread Matthew Garrett
On Tue, Oct 23, 2012 at 10:05:01AM -0600, Randy Wright wrote: > On the first: one way to be compliant with such a requirement would be > to design systems that implement softfail in this particular region. > What about a system that hardfails, but on which the resulting machine > check can be

Re: [PATCH RFC] function probe_roms accessing improper addresses

2012-10-23 Thread Randy Wright
Hi Matthew, You made some interesting suggestions: > 1) Declare that any x86 hardware supported by Linux *must* support > probing in this address region On the first: one way to be compliant with such a requirement would be to design systems that implement softfail in this particular region.

Re: [PATCH RFC] function probe_roms accessing improper addresses

2012-10-23 Thread Randy Wright
Hi Matthew, You made some interesting suggestions: 1) Declare that any x86 hardware supported by Linux *must* support probing in this address region On the first: one way to be compliant with such a requirement would be to design systems that implement softfail in this particular region.

Re: [PATCH RFC] function probe_roms accessing improper addresses

2012-10-23 Thread Matthew Garrett
On Tue, Oct 23, 2012 at 10:05:01AM -0600, Randy Wright wrote: On the first: one way to be compliant with such a requirement would be to design systems that implement softfail in this particular region. What about a system that hardfails, but on which the resulting machine check can be

Re: [PATCH RFC] function probe_roms accessing improper addresses

2012-10-19 Thread H. Peter Anvin
On 10/19/2012 08:30 AM, Matthew Garrett wrote: I don't think DMI checking is going to work, since (a) as you say, there's a risk that the ID will inadvertantly change over the lifecycle of the machine, and (b) there may be other machines. So if it's not possible to handle this by catching the

Re: [PATCH RFC] function probe_roms accessing improper addresses

2012-10-19 Thread Matthew Garrett
I don't think DMI checking is going to work, since (a) as you say, there's a risk that the ID will inadvertantly change over the lifecycle of the machine, and (b) there may be other machines. So if it's not possible to handle this by catching the MCE, I think we have two options: 1) Declare

Re: [PATCH RFC] function probe_roms accessing improper addresses

2012-10-19 Thread Randy Wright
I would like to summarize progress I have made on this issue in the past few days, and then appeal for help in evaluating the options. Matthew and H. Peter Anvin, I would appreciate your additional input especially. The general idea under consideration here is to avoid access to the legacy

Re: [PATCH RFC] function probe_roms accessing improper addresses

2012-10-19 Thread Randy Wright
I would like to summarize progress I have made on this issue in the past few days, and then appeal for help in evaluating the options. Matthew and H. Peter Anvin, I would appreciate your additional input especially. The general idea under consideration here is to avoid access to the legacy

Re: [PATCH RFC] function probe_roms accessing improper addresses

2012-10-19 Thread Matthew Garrett
I don't think DMI checking is going to work, since (a) as you say, there's a risk that the ID will inadvertantly change over the lifecycle of the machine, and (b) there may be other machines. So if it's not possible to handle this by catching the MCE, I think we have two options: 1) Declare

Re: [PATCH RFC] function probe_roms accessing improper addresses

2012-10-19 Thread H. Peter Anvin
On 10/19/2012 08:30 AM, Matthew Garrett wrote: I don't think DMI checking is going to work, since (a) as you say, there's a risk that the ID will inadvertantly change over the lifecycle of the machine, and (b) there may be other machines. So if it's not possible to handle this by catching the

Re: [PATCH RFC] function probe_roms accessing improper addresses

2012-10-09 Thread Randy Wright
> Date: Thu, 4 Oct 2012 20:22:56 +0100 > From: Matthew Garrett > To: rwri...@hp.com > Cc: linux-kernel@vger.kernel.org > Subject: Re: [PATCH RFC] function probe_roms accessing improper addresses > on UEFI systems > Message-ID: <20121004192256.ga6...@srcf.ucam.org>

Re: [PATCH RFC] function probe_roms accessing improper addresses

2012-10-09 Thread Randy Wright
Date: Thu, 4 Oct 2012 20:22:56 +0100 From: Matthew Garrett mj...@srcf.ucam.org To: rwri...@hp.com Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC] function probe_roms accessing improper addresses on UEFI systems Message-ID: 20121004192256.ga6...@srcf.ucam.org References

Re: [PATCH RFC] function probe_roms accessing improper addresses on UEFI systems

2012-10-04 Thread Matthew Garrett
On Wed, Oct 03, 2012 at 05:53:46PM -0600, Randy Wright wrote: > The following proposed patch takes advantage of the fact that on EFI > systems, the memory map provides a better description of the physical > space than on pre-EFI legacy systems. If the efi_enabled state variable > indicates the

Re: [PATCH RFC] function probe_roms accessing improper addresses on UEFI systems

2012-10-04 Thread Matthew Garrett
On Wed, Oct 03, 2012 at 05:53:46PM -0600, Randy Wright wrote: The following proposed patch takes advantage of the fact that on EFI systems, the memory map provides a better description of the physical space than on pre-EFI legacy systems. If the efi_enabled state variable indicates the kernel

[PATCH RFC] function probe_roms accessing improper addresses on UEFI systems

2012-10-03 Thread Randy Wright
The code in function probe_roms accesses the legacy adapter space (in the physical address range 640k-1mb) without regard to how this range is described in the memory map. The assumption in the code is that the result of an access to unpopulated space is a soft fail, returning -1. This assumption

[PATCH RFC] function probe_roms accessing improper addresses on UEFI systems

2012-10-03 Thread Randy Wright
The code in function probe_roms accesses the legacy adapter space (in the physical address range 640k-1mb) without regard to how this range is described in the memory map. The assumption in the code is that the result of an access to unpopulated space is a soft fail, returning -1. This assumption