linux-kernel - Re: [PATCH 2/4] x86: ioremap: fix physical address check

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Date:	Mon, 14 Jun 2010 22:16:36 +0200
From:	Rolf Eike Beer <eike-kernel@...tec.de>
To:	Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>
Cc:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
	linux-pci@...r.kernel.org, jbarnes@...tuousgeek.org
Subject: Re: [PATCH 2/4] x86: ioremap: fix physical address check

Kenji Kaneshige wrote:
> (2010/06/14 18:13), Kenji Kaneshige wrote:
> > Thank you Hiroyuki.
> > 
> > So many bugs in ioremap()...
> > 
> > Will try with those bugs fixed.
> > 
> > Thanks,
> > Kenji Kaneshige
> 
> The problem seems to be fixed by the following patch. This is still
> under testing. I will post the patch as v2 after testing.
> 
> Thanks,
> Kenji Kaneshige
> 
> 
> Current x86 ioremap() doesn't handle physical address higher than
> 32-bit properly in X86_32 PAE mode. When physical address higher than
> 32-bit is passed to ioremap(), higher 32-bits in physical address is
> cleared wrongly. Due to this bug, ioremap() can map wrong address to
> linear address space.
> 
> In my case, 64-bit MMIO region was assigned to a PCI device (ioat
> device) on my system. Because of the ioremap()'s bug, wrong physical
> address (instead of MMIO region) was mapped to linear address space.
> Because of this, loading ioatdma driver caused unexpected behavior
> (kernel panic, kernel hangup, ...).
> 
> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>
> 
> ---
>  arch/x86/mm/ioremap.c   |   11 +++++------
>  include/linux/io.h      |    4 ++--
>  include/linux/vmalloc.h |    2 +-
>  lib/ioremap.c           |   10 +++++-----
>  4 files changed, 13 insertions(+), 14 deletions(-)
> 
> Index: linux-2.6.34/arch/x86/mm/ioremap.c
> ===================================================================
> --- linux-2.6.34.orig/arch/x86/mm/ioremap.c
> +++ linux-2.6.34/arch/x86/mm/ioremap.c
> @@ -62,7 +62,8 @@ int ioremap_change_attr(unsigned long va
>  static void __iomem *__ioremap_caller(resource_size_t phys_addr,
>  		unsigned long size, unsigned long prot_val, void *caller)
>  {
> -	unsigned long pfn, offset, vaddr;
> +	u64 pfn, last_pfn;
> +	unsigned long offset, vaddr;
>  	resource_size_t last_addr;
>  	const resource_size_t unaligned_phys_addr = phys_addr;
>  	const unsigned long unaligned_size = size;

Why do you use u64 and not resource_size_t for those? That way this would not 
be needlessly big for "real" 32 bit platforms.

Eike

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