linux-kernel - Re: [PATCH 1/5] resources: add arch hook for preventing allocation in reserved areas

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Message-ID: <20101210123008.7fed582d@jbarnes-desktop>
Date:	Fri, 10 Dec 2010 12:30:08 -0800
From:	Jesse Barnes <jbarnes@...tuousgeek.org>
To:	Bjorn Helgaas <bjorn.helgaas@...com>
Cc:	Len Brown <lenb@...nel.org>, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Ingo Molnar <mingo@...e.hu>, Adam Belay <abelay@....edu>
Subject: Re: [PATCH 1/5] resources: add arch hook for preventing allocation
 in reserved areas

On Wed, 08 Dec 2010 14:36:06 -0700
Bjorn Helgaas <bjorn.helgaas@...com> wrote:

> 
> This adds arch_remove_reservations(), which an arch can implement if it
> needs to protect part of the address space from allocation.
> 
> Sometimes that can be done by just requesting a resource.  This hook is to
> cover cases where protected area doesn't fit well in the hierarchical
> resource tree.  For example, x86 BIOS E820 reservations are not related
> to devices, so they may overlap part of, all of, or more than a device
> resource.
> 
> Signed-off-by: Bjorn Helgaas <bjorn.helgaas@...com>
> ---

Hm, this is bigger than the simple change of just avoiding the high 2M;
Linus have you checked it out yet?  It's nicer than simply adjusting
PCIBIOS_MAX_MEM since it will affect all resource callers rather than
just PCI, but it's definitely bigger.

If you want just the simple change for 2.6.37 I can push that, but
we'll need to get a tested-by from Matthew:

  diff --git a/arch/x86/include/asm/pci.h b/arch/x86/include/asm/pci.h
  index ca0437c..aef9f77 100644
  --- a/arch/x86/include/asm/pci.h
  +++ b/arch/x86/include/asm/pci.h
  @@ -141,7 +141,7 @@ void dma32_reserve_bootmem(void);

   /* generic pci stuff */
   #include <asm-generic/pci.h>
  -#define PCIBIOS_MAX_MEM_32 0xffffffff
  +#define PCIBIOS_MAX_MEM_32 0xfff00000

   #ifdef CONFIG_NUMA
   /* Returns the node based on pci bus */

and I'll queue up this set for 2.6.38.

Thanks,
-- 
Jesse Barnes, Intel Open Source Technology Center
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