Re: [BUG][PATCH 0/2 (v.3)] x86: ioremap() problem in X86_32 PAE

[Kenji Kaneshige]

Hi,

I don't know what version of kernel you're using. But I guess you
might also need 4302e0fb7fa5b071e30f3cfb68e85155b3d69d9b (PCI: fix
wrong memory address handling in MSI-X).

Regards,
Kenji Kaneshige

(2011/02/10 23:11), TAKADA Yoshihito wrote:
> Hi.
> I faced same probrem, too. I use x86_64 kernel.
> Your patch fix it. it's very effective.
> Thanks!
>
> 2010å6æ18æ12:21 Kenji Kaneshige<kaneshige.kenji@xxxxxxxxxxxxxx>:
> > Hi,
> >
> > Here is a updated version (v.3) of patchset to fix ioremap() related
> > problem found in x86 32-bit mode. The problem is that ioremap() maps
> > wrong address for the device to which phisical addres higer than
> > 32-bit is assigned (ioat device in my case).
> >
> > The v.3 patches are:
> >
> > - [PATCH 1/2] x86: ioremap: fix wrong physical address handling
> > - [PATCH 2/2] x86: ioremap: fix normal ram range check
> >
> > Changelog
> > ---------
> > v.2=>v.3:
> > - Matthew Wilcox suggested changing PAGE_MASK definition. But I think
> >   it is a little risky. Instead of changing PAGE_MASK, v.3 patch uses
> >   PHYSICAL_PAGE_MASK(*) to mask physical address again, as v.1 patch
> >   did. The PHYSICAL_PAGE_MASK doesn't work for higher than 2^44
> >   physical address because __PHYSICAL_MASK_SHIFT is 44 in x86_32
> >   PAE(*). But this time, I focus on making 2^44 work correctly.
> >
> > (*) Current X86_32 PAE kernel would not work with physical address
> >     higher than 2^44, because PFNs are handled using 32-bit variable
> >     (unsigned long) probably in many places. This seems the reason why
> >     __PHYSICAL_MASK_SHIFT is limited to 44 (=32+12 is the limit we can
> >     fit into an unsigned long pfn). When x86 PAE linux becomes above
> >     2^44 physical address capable in someday, __PHYSICAL_MASK_SHIFT
> >     should become greater value than 44.
> >
> >
> > v.1=>v.2:
> > The v.1 patchset was based on my misunderstanding about architectural
> > limit and linux memory management limit of physical address. So some
> > patches in v.1 were totally wrong fixes and they are removed. Thanks
> > to the feedbacks for v.1 patchset, it turned out that phsical address
> > is handled improperly (higher 32-bits are cleared unexpectedly) also
> > in the other places than where v.1 patchset fixed. Here are summary of
> > changes.
> >
> > - Stop using PHYSICAL_PAGE_MASK to align physical address because
> >   PHYSICAL_PAGE_MASK would not work if physical address is higher than
> >   44-bit.
> > - Fix remaining bugs of physical address handling in ioremap() code
> >   path according to the feedbacks.
> > - Fix s_show() in vmalloc.c to show high physical address properly.
> > - Removed changes against phys_addr_valid() ([PATCH 2/4] in v.1).
> > - Removed changes against warning message in ioremap() ([PATCH 3/4] in
> >   v.1).
> >
> > Thanks,
> > Kenji Kaneshige
> >
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