resource: Add System RAM resource type

The IORESOURCE_MEM I/O resource type is used for all types of
memory-mapped ranges, ex. System RAM, System ROM, Video RAM,
Persistent Memory, PCI Bus, PCI MMCONFIG, ACPI Tables, IOAPIC,
reserved, and so on.

This requires walk_system_ram_range(), walk_system_ram_res(),
and region_intersects() to use strcmp() against string "System
RAM" to search for System RAM ranges in the iomem table, which
is inefficient. __ioremap_caller() and reserve_memtype() on x86,
for instance, call walk_system_ram_range() for every request to
check if a given range is in System RAM ranges.

However, adding a new I/O resource type for System RAM is not a
viable option, see [1]. There are approx. 3800 references to
IORESOURCE_MEM in the kernel/drivers, which makes it very
difficult to distinguish their usages between new type and
IORESOURCE_MEM.

The I/O resource types are also used by the PNP subsystem.
Therefore, introduce an extended I/O resource type,
IORESOURCE_SYSTEM_RAM, which consists of IORESOURCE_MEM and a
new modifier flag IORESOURCE_SYSRAM, see [2].

To keep the code 'if (resource_type(r) == IORESOURCE_MEM)' still
working for System RAM, resource_ext_type() is added for
extracting extended type bits.

Link[1]: http://lkml.kernel.org/r/[email protected]
Link[2]: http://lkml.kernel.org/r/CA+55aFy4WQrWexC4u2LxX9Mw2NVoznw7p3Yh=iF4Xtf7zKWnRw@mail.gmail.com

Signed-off-by: Toshi Kani <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Hanjun Guo <[email protected]>
Cc: Jakub Sitnicki <[email protected]>
Cc: Jiang Liu <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Luis R. Rodriguez <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Toshi Kani <[email protected]>
Cc: [email protected]
Cc: linux-mm <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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