Bartlomiej Zolnierkiewicz wrote:
Fix kernel oops due to machine check occuring in init_chipset_siimage() on PPC
44x platforms. These 32-bit CPUs have 36-bit physical address and PCI I/O and
memory spaces are mapped beyond 4 GB; arch/ppc/ code has a fixup in ioremap()
that creates an illusion of the PCI I/O and memory resources being mapped below
4 GB, while arch/powerpc/ code got rid of this fixup with PPC 44x having instead
CONFIG_RESOURCES_64BIT=y -- this causes the resources to be truncated to 32-bit
'unsigned long' type in this driver, and so non-existant memory being ioremap'ed
and then accessed...
Thanks to Valentine Barshak for providing an initial patch and explanations.
Signed-off-by: Sergei Shtylyov <sshtylyov@xxxxxxxxxxxxx>
applied and pushed to Linus, thanks!
I guess that it would be worth to audit the rest of IDE code for
Already done. Some drivers, like sgiioc4, scc_pata, and pmac are prone to
that at least in theory. Although I doubt that they ever get used in such
environments as PPC 44x platform kernels, i.e. 32-bit kernel and PCI mapped
beyond 4 GB.
pci_resource_{start,end}() vs 'unsigned long' occurences and fix them.
There are quite a lot of those overall but they only pose danger if the
resource in question is in memory space since the I/O space always uses
'unsigned long' addresses. So, IDE core and drivers using only I/O resources
should not be prone to that kind of issue.
[ Even if they work at the moment they are just bugs waiting to happened
when we add support for some new platforms or rewrite the code... ]
WBR, Sergei
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