* Jiang Liu <jiang....@linux.intel.com> wrote:
> Since commit 593669c2ac0f ("x86/PCI/ACPI: Use common ACPI resource interfaces
> to
> simplify implementation"), x86 PCI ACPI host bridge driver validates ACPI
> resources by first converting an ACPI resource to a 'struct resource'
> structure
> and then applying checks against the converted resource structure. The
> 'start'
> and 'end' fields in 'struct resource' are defined to be type of
> resource_size_t,
> which may be 32 bits or 64 bits depending on CONFIG_PHYS_ADDR_T_64BIT.
>
> This may cause incorrect resource validation results with 32 bit kernels
> because
> 64bit ACPI resource descriptors may get truncated when converting to 32bit
> 'start' and 'end' fields in 'struct resource'. And eventually affects PCI
> resource allocation subsystem and causes some PCI devices unusable.
s/causes some PCI devices unusuable.
makes some PCI devices unusuable.
Also, this description is still pretty vague. What exactly happened? Did some
PCI
devices not show up during bootup? Or did they hang? Or did something else
happen?
This is _by far_ the most important part of the changelog and determines
whether a
patch gets backported or not. Why does a usable regression description have to
be
coaxed out of you like pulling teeth??
> So enhance the ACPI resource parsing interfaces to ignore ACPI resource
> descriptors with address/offset observe 4G when running in 32bit mode. This
> reverts to the behavior before commit 593669c2ac0f.
>
> This issue was triggered on a platform running 32bit kernel with an ACPI
> resource descriptor with address range [0x400000000-0xfffffffff]. Please
> refer
> to https://lkml.org/lkml/2015/6/19/277 for more information.
s/32bit/32-bit
s/64bit/64-bit
s/32 bit/32-bit
s/64 bit/64-bit
Thanks,
Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
