On 08/05/2010 05:15 PM, tip-bot for Eric W. Biederman wrote: > Commit-ID: 5989cd6a1cbf86587edcc856791f960978087311 > Gitweb: http://git.kernel.org/tip/5989cd6a1cbf86587edcc856791f960978087311 > Author: Eric W. Biederman <ebiederm@xxxxxxxxxxxx> > AuthorDate: Wed, 4 Aug 2010 13:30:27 -0700 > Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx> > CommitDate: Thu, 5 Aug 2010 16:26:42 -0700 > > x86, apic: Map the local apic when parsing the MP table. > > This fixes a regression in 2.6.35 from 2.6.34, that is > present for select models of Intel cpus when people are > using an MP table. > > The commit cf7500c0ea133d66f8449d86392d83f840102632 > "x86, ioapic: In mpparse use mp_register_ioapic" started > calling mp_register_ioapic from MP_ioapic_info. An extremely > simple change that was obviously correct. Unfortunately > mp_register_ioapic did just a little more than the previous > hand crafted code and so we gained this call path. > > The problem call path is: > MP_ioapic_info() > mp_register_ioapic() > io_apic_unique_id() > io_apic_get_unique_id() > get_physical_broadcast() > modern_apic() > lapic_get_version() > apic_read(APIC_LVR) > > Which turned out to be a problem because the local apic > was not mapped, at that point, unlike the similar point > in the ACPI parsing code. > > This problem is fixed by mapping the local apic when > parsing the mptable as soon as we reasonably can. > > Looking at the number of places we setup the fixmap for > the local apic, I see some serious simplification opportunities. > For the moment except for not duplicating the setting up of the > fixmap in init_apic_mappings, I have not acted on them. > > The regression from 2.6.34 is tracked in bug > https://bugzilla.kernel.org/show_bug.cgi?id=16173 > > Cc: <stable@xxxxxxxxxx> 2.6.35 > Reported-by: David Hill <hilld@xxxxxxxxxxxxxxx> > Reported-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxx> > Tested-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxx> > Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx> > LKML-Reference: <m1eiee86jg.fsf_-_@xxxxxxxxxxxxxxxxx> > Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx> > --- > arch/x86/kernel/apic/apic.c | 2 +- > arch/x86/kernel/mpparse.c | 16 ++++++++++++++++ > 2 files changed, 17 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c > index a96489e..c07e513 100644 > --- a/arch/x86/kernel/apic/apic.c > +++ b/arch/x86/kernel/apic/apic.c > @@ -1606,7 +1606,7 @@ void __init init_apic_mappings(void) > * acpi lapic path already maps that address in > * acpi_register_lapic_address() > */ > - if (!acpi_lapic) > + if (!acpi_lapic && !smp_found_config) > set_fixmap_nocache(FIX_APIC_BASE, apic_phys); > > apic_printk(APIC_VERBOSE, "mapped APIC to %08lx (%08lx)\n", this change is not needed, it will break: 1. found mptable, but is using default contruct path. 2. visws path, found found mptable, but get_smp_conf is not called. YH -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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