• Luis R. Rodriguez's avatar
    x86, drivers/pnpbios: Replace paravirt_enabled() check with legacy device check · 80dfd83d
    Luis R. Rodriguez authored
    Since we are removing paravirt_enabled() replace it with a
    logical equivalent. Even though PNPBIOS is x86 specific we
    add an arch-specific type call, which can be implemented by
    any architecture to show how other legacy attribute devices
    can later be also checked for with other ACPI legacy attribute
    flags.
    
    This implicates the first ACPI 5.2.9.3 IA-PC Boot Architecture
    ACPI_FADT_LEGACY_DEVICES flag device, and shows how to add more.
    
    The reason pnpbios gets a defined structure and as such uses
    a different approach than the RTC legacy quirk is that ACPI
    has a respective RTC flag, while pnpbios does not. We fold
    the pnpbios quirk under ACPI_FADT_LEGACY_DEVICES ACPI flag
    use case, and use a struct of possible devices to enable
    future extensions of this.
    
    As per 0-day, this bumps the vmlinux size using i386-tinyconfig as
    follows:
    
    TOTAL   TEXT   init.text   x86_early_init_platform_quirks()
    +32     +28    +28         +28
    
    That's 4 byte overhead total, the rest is cleared out on init
    as its all __init text.
    
    v2: split out subarch handlng on switch to make it easier
        later to add other subarchs. The 'fall-through' switch
        handling can be confusing and we'll remove it later
        when we add handling for X86_SUBARCH_CE4100.
    v3: document vmlinux size impact as per 0-day, and also
        explain why pnpbios is treated differently than the
        RTC legacy feature.
    Signed-off-by: 's avatarLuis R. Rodriguez <mcgrof@kernel.org>
    Cc: Andy Lutomirski <luto@amacapital.net>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Brian Gerst <brgerst@gmail.com>
    Cc: Denys Vlasenko <dvlasenk@redhat.com>
    Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: andrew.cooper3@citrix.com
    Cc: andriy.shevchenko@linux.intel.com
    Cc: bigeasy@linutronix.de
    Cc: boris.ostrovsky@oracle.com
    Cc: david.vrabel@citrix.com
    Cc: ffainelli@freebox.fr
    Cc: george.dunlap@citrix.com
    Cc: glin@suse.com
    Cc: jgross@suse.com
    Cc: jlee@suse.com
    Cc: josh@joshtriplett.org
    Cc: julien.grall@linaro.org
    Cc: konrad.wilk@oracle.com
    Cc: kozerkov@parallels.com
    Cc: lenb@kernel.org
    Cc: lguest@lists.ozlabs.org
    Cc: linux-acpi@vger.kernel.org
    Cc: lv.zheng@intel.com
    Cc: matt@codeblueprint.co.uk
    Cc: mbizon@freebox.fr
    Cc: rjw@rjwysocki.net
    Cc: robert.moore@intel.com
    Cc: rusty@rustcorp.com.au
    Cc: tiwai@suse.de
    Cc: toshi.kani@hp.com
    Cc: xen-devel@lists.xensource.com
    Link: http://lkml.kernel.org/r/1460592286-300-12-git-send-email-mcgrof@kernel.orgSigned-off-by: 's avatarIngo Molnar <mingo@kernel.org>
    80dfd83d
pnp.h 15.4 KB