Messages in this thread | | | Date | Mon, 7 Dec 2009 16:48:51 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [tip:x86/urgent] x86: Fix bogus warning in apic_noop.apic_write() |
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On Mon, 7 Dec 2009, Cyrill Gorcunov wrote: > On Mon, Dec 07, 2009 at 12:18:37PM +0000, tip-bot for Thomas Gleixner wrote: > > Commit-ID: a946d8f11f0da9cfc714248036fcfd3a794d1e27 > > Gitweb: http://git.kernel.org/tip/a946d8f11f0da9cfc714248036fcfd3a794d1e27 > > Author: Thomas Gleixner <tglx@linutronix.de> > > AuthorDate: Mon, 7 Dec 2009 12:59:46 +0100 > > Committer: Ingo Molnar <mingo@elte.hu> > > CommitDate: Mon, 7 Dec 2009 13:16:37 +0100 > > > > x86: Fix bogus warning in apic_noop.apic_write() > > > > apic_noop is used to provide dummy apic functions. It's installed > > when the CPU has no APIC or when the APIC is disabled on the kernel > > command line. > > > > The apic_noop implementation of apic_write() warns when the CPU has > > an APIC or when the APIC is not disabled. > > > > That's bogus. The warning should only happen when the CPU has an > > APIC _AND_ the APIC is not disabled. apic_noop.apic_read() has the > > correct check. > > > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > > Cc: Cyrill Gorcunov <gorcunov@openvz.org> > > Cc: <stable@kernel.org> # in <= .32 this typo resides in native_apic_write_dummy() > > LKML-Reference: <alpine.LFD.2.00.0912071255420.3089@localhost.localdomain> > > Signed-off-by: Ingo Molnar <mingo@elte.hu> > > --- > > arch/x86/kernel/apic/apic_noop.c | 2 +- > > 1 files changed, 1 insertions(+), 1 deletions(-) > ... > > Hi Thomas, Ingo, > > please do not change it. There are still machines without > cpu_has_apic bit support so with this patch any attempt > to write to 82489DX will success. So the former code has > been using "OR" by a purpose, there is no error.
Err, your warning has the following false positive:
cpu_has_apic == true and disable_apic == true
Which is crap, as it warns just because someone disabled the APIC on the command line and the kernel did the right thing of installing apic_noop.
And I have a hard time to see how this is related to 82489DX.
Thanks,
tglx
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