• Robert Hancock's avatar
    x86: validate against acpi motherboard resources · 7752d5cf
    Robert Hancock authored
    This path adds validation of the MMCONFIG table against the ACPI reserved
    motherboard resources.  If the MMCONFIG table is found to be reserved in
    ACPI, we don't bother checking the E820 table.  The PCI Express firmware
    spec apparently tells BIOS developers that reservation in ACPI is required
    and E820 reservation is optional, so checking against ACPI first makes
    sense.  Many BIOSes don't reserve the MMCONFIG region in E820 even though
    it is perfectly functional, the existing check needlessly disables MMCONFIG
    in these cases.
    
    In order to do this, MMCONFIG setup has been split into two phases.  If PCI
    configuration type 1 is not available then MMCONFIG is enabled early as
    before.  Otherwise, it is enabled later after the ACPI interpreter is
    enabled, since we need to be able to execute control methods in order to
    check the ACPI reserved resources.  Presently this is just triggered off
    the end of ACPI interpreter initialization.
    
    There are a few other behavioral changes here:
    
    - Validate all MMCONFIG configurations provided, not just the first one.
    
    - Validate the entire required length of each configuration according to
      the provided ending bus number is reserved, not just the minimum required
      allocation.
    
    - Validate that the area is reserved even if we read it from the chipset
      directly and not from the MCFG table.  This catches the case where the
      BIOS didn't set the location properly in the chipset and has mapped it
      over other things it shouldn't have.
    
    This also cleans up the MMCONFIG initialization functions so that they
    simply do nothing if MMCONFIG is not compiled in.
    
    Based on an original patch by Rajesh Shah from Intel.
    
    [akpm@linux-foundation.org: many fixes and cleanups]
    Signed-off-by: default avatarRobert Hancock <hancockr@shaw.ca>
    Signed-off-by: default avatarAndi Kleen <ak@suse.de>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Greg KH <greg@kroah.com>
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Tested-by: default avatarAndi Kleen <ak@suse.de>
    Cc: Rajesh Shah <rajesh.shah@intel.com>
    Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
    Acked-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    Cc: Andi Kleen <ak@suse.de>
    Cc: Greg KH <greg@kroah.com>
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    7752d5cf
bus.c 19.2 KB